Printed material and method for manufacturing printed material

Abstract

To provide a printed material in which edge breakage that occurs when crimp surfaces of the printed material are peeled is suppressed.SOLUTION: There is provided a printed material in which a recording medium is folded and crimped with a surface where an image portion and a pressure phase transition layer are formed as a crimp surface or a recording medium and another recording medium are superimposed on each other and crimped with a surface where the image portion and the pressure phase transition layer are formed as a crimp surface. When the crimp surfaces of the printed matter are peeled and a surface equivalent to the crimp surface of the printed material in an unfolded material obtained by unfolding the printed material is observed, an exposed area ratio EA of the pressure phase transition layer in a region at a distance up to 0.5 mm to the inner side from the edge of the crimp surface in an outer edge portion E located in a location corresponding to at least one of edges of the crimp surface is smaller than an exposed area ratio IA of the pressure phase transition layer in a center portion I of the crimp surface.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to printed matter and a method for manufacturing the same.

Background Art

[0002] Patent Document 1 discloses "a method for manufacturing a printed matter, comprising: a first step of forming an image on a recording medium; a second step of applying pressure-responsive particles onto the surface of the recording medium on which the image is formed; a third step of heating the pressure-responsive particles applied to the recording medium; and a fourth step of pressing, in the thickness direction, a laminate formed by folding the recording medium with the heated pressure-responsive particles interposed therebetween, or a laminate formed by overlapping the recording medium and another medium with the heated pressure-responsive particles interposed therebetween."

[0003] Patent Document 2 discloses "an adhesive application method, characterized in that when two surfaces of a pressure-bonding object are pressure-bonded, the amount of an adhesive applied to a portion corresponding to an image portion sandwiched between the two surfaces is increased, and the adhesive applied outside the portion corresponding to the image portion is decreased, and the adhesive is applied to the pressure-bonding surface of the pressure-bonding object."

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The object of the present invention is to provide a printed material in which, when the pressed surfaces of the printed material are peeled apart and the surface corresponding to the pressed surface of the printed material is observed, compared to the case where the exposure area ratio EA of the pressure-transition layer in the region at a distance of 0.5 mm inward from the edge of the pressed surface at the outer edge E corresponding to at least one edge of the edge of the pressed surface is the same as the exposure area ratio IA of the pressure-transition layer in the central part I of the pressed surface, when the pressed surfaces of the printed material are peeled apart and the surface corresponding to the pressed surface of the printed material in the unfolded material is observed, edge tearing that occurs when the pressed surface of the printed material is peeled off is suppressed. [Means for solving the problem]

[0006] The following embodiments are included as specific means for solving the aforementioned problems. <1> The recording medium is folded and pressed together using the surface on which the image portion and the pressure-transition layer are formed as the bonding surface, or the recording medium and another recording medium are stacked and pressed together using the surface on which the image portion and the pressure-transition layer are formed as the bonding surface. A printed material in which, when the pressure-bonded surfaces of the printed material are separated and the surface corresponding to the pressure-bonded surface of the printed material is observed, the exposed area ratio EA of the pressure-phase transition layer in the region at a distance of 0.5 mm inward from the edge of the pressure-bonded surface at the outer edge E corresponding to at least one edge of the edge of the pressure-bonded surface is smaller than the exposed area ratio IA of the pressure-phase transition layer in the central part I of the pressure-bonded surface. <2> The ratio (EA / IA) of the exposed area ratio EA of the pressure phase transition layer to the exposed area ratio IA of the pressure phase transition layer is 0 or greater and 0.95 or less. <1> The printed material described above. <3> The exposure area ratio EA of the pressure phase transition layer is 5% or more and 95% or less. <2> The printed material described above. <4> In the outer edge portion E, the width of the region where the exposed area ratio of the pressure phase transition layer is smaller than the exposed area ratio IA of the pressure phase transition layer in the central portion I of the bonding surface is 1 mm or more and 5 mm or less. <1> ~ <3> Any printed material described in any one of the items. <5> The outer edge portion E has a region where the pressure phase transition layer is not formed. <1> ~ <4> Any printed material described in any one of the items. <6> In the outer edge portion E, at least a portion of the upper layer of the pressure phase transition layer has a non-pressure phase transition layer. <1> ~ <5> Any printed material described in any one of the items. <7> In the outer edge portion E, the linear or strip-shaped pressure phase transition layers are arranged. <1> ~ <6> Any printed material described in any one of the items. <8> The pressure-transition-resistant layer comprises a styrene-based resin containing styrene and other vinyl monomers as polymerization components, and a (meth)acrylic acid ester-based resin containing at least two types of (meth)acrylic acid esters as polymerization components, wherein the mass ratio of (meth)acrylic acid esters to the total polymerization components is 90% by mass or more, and has at least two glass transition temperatures, wherein the difference between the lowest and highest glass transition temperatures exhibited by the pressure-transition-resistant layer is 30°C or more. <1> ~ <7> Any printed material described in any one of the items. <9> The mass percentage of styrene in the total polymerization components of the styrene-based resin is 60% by mass or more and 95% by mass or less. <8> The printed material described above. <10> The mass ratio of the two most abundant of the at least two (meth)acrylic acid esters contained as polymerization components in the (meth)acrylic acid ester resin is 80:20 to 20:80. <8> or <9> The printed material described above. <11> A pressure phase transition particle application step in which pressure phase transition particles are applied to a recording medium on which an image portion is formed, A fixing step of fixing at least the pressure-phase-transition particles onto the recording medium to form a pressure-phase-transition layer, A crimping step in which the recording medium is folded and crimped with the surface on which the image portion and the pressure phase transition layer are formed serving as the crimping surface, or the recording medium is stacked and crimped with another recording medium with the surface on which the image portion and the pressure phase transition layer are formed serving as the crimping surface, It has, In the pressure-phase-transition particle application step, when a region to which the pressure-phase-transition particles are applied is selected on the recording medium, the pressed surfaces of the resulting printed material are separated, and the surface corresponding to the pressed surface of the printed material in the unfolded material is observed, at the outer edge E corresponding to at least one of the edges of the pressed surface, the exposed area ratio EA of the pressure-phase-transition layer in the region at a distance of 0.5 mm inward from the edge of the pressed surface is smaller than the exposed area ratio IA of the pressure-phase-transition layer in the central part I of the pressed surface. <1> ~ <10> A method for manufacturing printed materials as described in any one of the items. <12> A pressure phase transition particle application step in which pressure phase transition particles are applied to a recording medium on which an image portion is formed, A fixing step of fixing at least the pressure-phase-transition particles onto the recording medium to form a pressure-phase-transition layer, A crimping step in which the recording medium is folded and crimped with the surface on which the image portion and the pressure phase transition layer are formed serving as the crimping surface, or the recording medium is stacked and crimped with another recording medium with the surface on which the image portion and the pressure phase transition layer are formed serving as the crimping surface, It has, When a non-pressure phase transition layer is formed on top of at least a portion of the pressure phase transition layer, and the resulting printed materials are separated and the surfaces corresponding to the pressed surfaces of the printed materials are observed in the unfolded material, the exposed area ratio EA of the pressure phase transition layer in the region at a distance of 0.5 mm inward from the edge of the pressed surface, at the outer edge E corresponding to at least one of the edges of the edge of the pressed surface, reduces the exposed area ratio IA of the pressure phase transition layer in the central part I of the pressed surface. <1> ~ <10> A method for manufacturing printed materials as described in any one of the items. <13> In the pressing step, with the end side where the outer edge portion E is located in a laminate obtained by stacking the recording media or in a laminate obtained by stacking the recording media and another recording media as the rear end, the laminate is passed through a pressing device and pressed according to <11> or <12>. [Advantages of the Invention]

[0007] According to the invention according to <1>, <5> or <6>, in a printed matter in which the recording media are stacked and pressed with the surface on which the image portion and the pressure transferable layer are formed as the pressing surface, or in a printed matter in which the recording media and another recording media are stacked and pressed with the surface on which the image portion and the pressure transferable layer are formed as the pressing surface, when the pressing surfaces of the printed matter are peeled off and the surface corresponding to the pressing surface of the printed matter in the unfolded matter obtained by unfolding the printed matter is observed, the exposed area ratio EA of the pressure transferable layer in the region at a distance of up to 0.5 mm from the end of the pressing surface at the outer edge portion E at a position corresponding to at least one side of the central portion I side of the pressing surface and the exposed area ratio IA of the pressure transferable layer in the central portion I of the pressing surface are the same. Compared with the case, a printed matter in which edge breakage that occurs when the pressing surface of the printed matter is peeled off is suppressed is provided.

[0008] According to the invention according to <2>, compared with the case where the ratio (EA / IA) of the exposed area ratio EA of the pressure transferable layer and the exposed area ratio IA of the pressure transferable layer is less than 0.05, edge peeling of the printed matter is suppressed, and compared with the case where the ratio (EA / IA) exceeds 0.95, a printed matter in which edge breakage that occurs when the pressing surface of the printed matter is peeled off is suppressed is provided. According to the invention according to <3>, compared with the case where the exposed area ratio EA of the pressure transferable layer is less than 5%, edge peeling of the printed matter is suppressed, and compared with the case where the exposed area ratio EA of the pressure transferable layer exceeds 95%, a printed matter in which edge breakage that occurs when the pressing surface of the printed matter is peeled off is suppressed is provided.

[0009] According to the invention according to <4>, compared with the case where the width of the outer edge portion E is less than 0.5 mm, end breakage that occurs when the pressure-bonding surface of the printed matter is peeled off is suppressed, and compared with the case where the width of the outer edge portion exceeds 5.0 mm, a printed matter in which end peeling of the printed matter is suppressed is provided.

[0010] According to the invention according to <7>, in the outer edge portion E, compared with the case where the linear or strip-shaped pressure-transferable layer is arranged in a dot pattern, end peeling of the printed matter is suppressed.

[0011] According to the invention according to <10> or <11>, in a method for manufacturing a printed matter in which a recording medium is folded and pressure-bonded with the surface on which the image portion and the pressure-transferable layer are formed as the pressure-bonding surface, or the recording medium and another recording medium are overlapped and pressure-bonded with the surface on which the image portion and the pressure-transferable layer are formed as the pressure-bonding surface, when the pressure-bonding surfaces of the obtained printed matter are peeled off and the surface corresponding to the pressure-bonding surface of the printed matter in the unfolded product obtained by unfolding the printed matter is observed, compared with the case where the exposed area ratio EA of the pressure-transferable layer in the region at a distance of 0.5 mm from the end of the pressure-bonding surface to the inside in the outer edge portion E at a position corresponding to at least one side of the end side of the pressure-bonding surface is the same as the exposed area ratio IA of the pressure-transferable layer in the central portion I of the pressure-bonding surface, a method for manufacturing a printed matter in which end breakage that occurs when the pressure-bonding surface of the printed matter is peeled off is suppressed is provided.

[0012] According to the invention according to <12>, in the pressure-bonding step, compared with the case where the laminate in which the recording media are folded or the laminate in which the recording medium and another recording medium are overlapped is passed through a pressure-applying device and pressure-bonded with the end side where the outer edge portion E is located as the tip, a method for manufacturing a printed matter in which end breakage that occurs when the pressure-bonding surface of the printed matter is peeled off is suppressed is provided.

Brief Description of Drawings

[0013] [Figure 1] It is a schematic plan view showing an example of an unfolded product obtained by unfolding the printed matter according to the present embodiment. [Figure 2] It is a schematic plan view showing another example of an unfolded product obtained by unfolding the printed matter according to the present embodiment. [Figure 3] This is a schematic partial plan view showing an example of the arrangement pattern of the pressure phase transition layer at the outer edge E of a printed material unfolded according to this embodiment. [Figure 4A] This is a schematic partial plan view showing an example of the arrangement pattern of the non-pressure phase transition layer at the outer edge E of a printed material unfolded according to this embodiment. [Figure 4B] This is a cross-sectional view taken along line A1-A1 in Figure 4A. [Figure 5] This is a schematic diagram showing an example of a printing system according to this embodiment. [Figure 6] This is a schematic diagram showing another example of the printing manufacturing system according to this embodiment. [Modes for carrying out the invention]

[0014] Embodiments of the present invention are described below. These descriptions and examples are illustrative and do not limit the scope of the embodiments.

[0015] In numerical ranges described stepwise within this specification, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described stepwise. Furthermore, in numerical ranges described within this specification, the upper or lower limit of that range may be replaced with the values ​​shown in the examples.

[0016] In this specification, the term "process" includes not only independent processes but also processes that are not clearly distinguishable from other processes, provided that their intended purpose is achieved.

[0017] When embodiments are described herein with reference to the drawings, the configuration of such embodiments is not limited to that shown in the drawings. Furthermore, the sizes of the components in each figure are conceptual, and the relative relationships between the components are not limited thereto.

[0018] In this specification, each component may contain multiple types of the corresponding substance. When referring to the amount of each component in a composition in this specification, if there are multiple types of the substance corresponding to that component in the composition, unless otherwise specified, it means the total amount of those multiple types of substances present in the composition.

[0019] In this specification, each component may contain multiple types of particles. When multiple types of particles corresponding to each component are present in a composition, the particle size of each component refers to the value for a mixture of such multiple types of particles present in the composition, unless otherwise specified.

[0020] In this specification, the term "(meth)acrylic" means that either "acrylic" or "methacrylic" is acceptable.

[0021] In this specification, "peel strength" is an index indicating the degree of peeling between opposing surfaces (i.e., bonding surfaces) of the above recording medium, and is substantially synonymous with "adhesion," which indicates the degree of bonding. Hereafter, when simply referred to as "peel strength," it refers to the peel strength between opposing surfaces (i.e., bonding surfaces) of the above recording medium, and when simply referred to as "adhesion," it refers to the adhesion between opposing surfaces (i.e., bonding surfaces) of the above recording medium.

[0022] [Printed material] The printed material according to this embodiment is a printed material in which a recording medium is folded and pressed together with the surface on which the image portion and the pressure-transitionable layer are formed serving as the pressing surface, or a recording medium is stacked and pressed together with another recording medium with the surface on which the image portion and the pressure-transitionable layer are formed serving as the pressing surface. Furthermore, when the pressed surfaces of the printed materials are separated and the surface corresponding to the pressed surface in the unfolded material is observed, the exposed area ratio EA of the pressure phase transition layer in the region at a distance of 0.5 mm inward from the edge of the pressed surface, at the outer edge E corresponding to at least one of the edges of the edge of the pressed surface, is smaller than the exposed area ratio IA of the pressure phase transition layer in the central part I of the pressed surface.

[0023] Here, "another recording medium" refers to a recording medium whose surface has at least a pressure-transition-resistant layer formed on it as the bonding surface. Printed materials that are folded and pressed together on a recording medium, and printed materials that are pressed together on top of another recording medium, are also called "pressure-sealed printed materials." "Outer edge E" refers to the outer edge of the surface corresponding to the pressure-bonding surface in the unfolded printed material, and indicates the region within a distance of 5.0 mm inward from the edge of the pressure-bonding surface. "Central area I" refers to the central part of the surface corresponding to the pressure-bonding surface in the unfolded printed material, and the area located at a distance greater than 5.0 mm inward from the edge of the pressure-bonding surface.

[0024] In this embodiment, the above configuration suppresses tearing at the edges of the printed material when the pressure-bonded surface is peeled off. The reason for this is presumed to be as follows.

[0025] Printed materials are known in which a recording medium is folded and pressed together with a surface coated with UV varnish or water-based varnish as the pressing surface, or in which a recording medium is stacked and pressed together with another recording medium with a surface coated with UV varnish or water-based varnish as the pressing surface. Furthermore, there are also known printed materials in which a recording medium is folded and pressed together using the surface on which the image portion and the pressure-transition layer are formed as the pressing surface, or in which a recording medium is stacked and pressed together using the surface on which the image portion and the pressure-transition layer are formed as the pressing surface.

[0026] However, when the pressed surfaces of printed materials are separated and the printed materials are unfolded, tearing of the edges may occur. This is thought to be because, when a laminate made by folding recording media, or a laminate made by stacking one recording media and another recording media, is passed through a pressurizing device and pressed, pressure is more easily applied to the outer edges of the laminate than to the center, and the pressing force on the outer edges of the pressed surface of the printed material increases. In particular, pressure is more easily applied to the rear end of the laminate when it is passed through the pressurizing device, and the pressing force on the outer edges located at that rear end of the pressed surface of the printed material tends to increase, making tearing of the edges more likely.

[0027] In contrast, in the printed material according to this embodiment, when observing the surface corresponding to the crimping surface in the unfolded material, the exposure area ratio EA of the pressure phase transition layer in the region at a distance of 0.5 mm inward from the edge of the crimping surface at the outer edge E corresponding to at least one of the edges of the edge of the crimping surface is made smaller than the exposure area ratio IA of the pressure phase transition layer in the central part I of the crimping surface. As a result, when the laminate is passed through a pressurizing device and pressed, even if excessive pressure is applied to the outer edge of the laminate, the increase in the pressing force on the outer edge of the pressed surface of the printed material is suppressed.

[0028] Therefore, it is presumed that in the printed material according to this embodiment, edge tearing that occurs when the pressure-bonded surface of the printed material is peeled off is suppressed.

[0029] The details of the printed material according to this embodiment will be described below.

[0030] (Image section, pressure phase transition layer, and recording medium) The image portion may include a toner image portion formed on a recording medium using an electrophotographic method, an ink image portion formed using an inkjet method, and so on. A pressure-phase-transition layer is a layer formed by impregnating and fixing pressure-phase-transition particles onto a recording medium. Examples of recording media include paper, coated paper (paper with a resin coating on its surface), cloth, nonwoven fabric, resin film, and resin sheet. Details of the image section and the pressure phase transition layer will be explained in detail in the printing method described later.

[0031] (Percentage of exposed area of ​​the pressure phase transition layer) In the printed material according to this embodiment, when the pressed surfaces of the printed material are separated and the unfolded material is observed, the exposed area ratio EA of the pressure phase transition layer in the region at a distance of 0.5 mm inward from the edge of the pressed surface, at the outer edge E corresponding to at least one of the edges of the edge of the pressed surface, is smaller than the exposed area ratio IA of the pressure phase transition layer in the central part I of the pressed surface.

[0032] Specifically, it is as follows: First, as an example, Figure 1 shows an example of an unfolded printed material that has been heat-pressed in a V-fold. The unfolded material shown in Figure 1 has outer edges E11, E12, E21, E22, E31, and E32 on its surface, which are located at the edges of the crimping surface on the surface corresponding to the crimping surface. In at least one of the outer edges E11, E12, E21, E22, E31, and E32, the exposed area ratio EA of the pressure phase transition layer in the region at a distance of 0.5 mm inward from the edge of the crimping surface is smaller than the exposed area ratio IA of the pressure phase transition layer in the central part C10 of the crimping surface. In Figure 1, the area enclosed by the thick border corresponds to the crimped surface in the unfolded material, and the dotted lines indicate the parts that were folded during the printing process.

[0033] As another example, Figure 2 shows an example of an unfolded printed material that has been compressed using a Z-fold. The unfolded material shown in Figure 2 has outer edges E11, E12, E21, E22, E31, and E32, which are located at the edges of the crimping surface on the surface corresponding to the crimping surface of the printed material. In at least one of the outer edges E11, E12, E21, E22, E31, and E32, the exposed area ratio EA of the pressure phase transition layer in the region at a distance of 0.5 mm inward from the edge of the crimping surface is smaller than the exposed area ratio IA of the pressure phase transition layer in the central part C10 of the crimping surface. The unfolded material shown in Figure 1 is a printed material that has been pressed together using a Z-fold; therefore, the reverse side of the unfolded material should be in a similar state. In Figure 2, the area enclosed by the thick border corresponds to the pressure-sealed surface of the printed material in the unfolded document, the dotted line indicates the part that was folded during the printing process, and the dashed line indicates the part that was folded during the printing process.

[0034] The outer edges E, where the exposed area ratio EA of the pressure phase transition layer is smaller than the exposed area ratio IA of the pressure phase transition layer in the central part C10 of the crimping surface, are preferably all of the outer edges E11, E12, E21, E22, E31, and E32. However, it is more preferable that, at least during the manufacturing process of printed materials, the outer edge portion located at the rear end of the laminate when the laminate, which is formed by folding recording media or by stacking the recording media and another recording media, passes through a pressurizing device, has an outer edge portion E with an exposed area ratio EA of the pressure phase transition layer that is smaller than the exposed area ratio IA of the pressure phase transition layer in the central portion C10 of the crimping surface. Specifically, in Figures 1 and 2, when the direction indicated by the arrow is the direction in which the laminate passes through the pressurizing device, the outer edge E, which has an exposed area ratio EA of the pressure phase transition layer that is smaller than the exposed area ratio IA of the pressure phase transition layer in the central part C10 of the crimping surface, is preferably at least outer edge E11 and outer edge 21. More preferably, the outer edge E is the opposing outer edge E11 and outer edge E12, and outer edge E21 and outer edge E22. As a result, when passing through the pressurizing device, the tearing of the edges of the printed material that occurs when the pressed surface of the printed material is peeled off is suppressed at the rear end of the laminate, where the pressure is most easily applied and the bonding force is most likely to increase.

[0035] The ratio (EA / IA) of the exposed area ratio EA of the pressure phase transition layer to the exposed area ratio IA of the pressure phase transition layer is preferably 0 to 0.95, more preferably 0.05 to 0.95, even more preferably 0.15 to 0.85, and particularly preferably 0.25 to 0.75. By setting the ratio (EA / IA) to 0 or greater, excessive pressure reduction is suppressed at the edges of the printed material located in the corresponding outer edge, thereby preventing edge peeling. Here, a ratio (EA / IA) of "0" indicates that the exposed area ratio EA of the pressure phase transition layer is 0%. By setting the ratio (EA / IA) to 0.95 or less, edge tearing that occurs when the pressure-bonded surface of the printed material is peeled off is further suppressed.

[0036] The exposure area ratio EA of the pressure phase transition layer is preferably 0% to 95%, more preferably 5% to 95%, even more preferably 25% to 85%, and particularly preferably 35% to 75%. However, among the outer edges E11, E12, E21, E22, E31, and E32 located at the edges of the crimping surface, the exposed area ratio EA of the pressure phase transition layer in the region at a distance of 0.5 mm inward from the edge of the crimping surface in at least one of the outer edges E11 and E12, at least one of the outer edges E21 and E22, or at least one of the outer edges E31 and E32 that face each other when crimped is preferably 5% to 95%, more preferably 25% to 85%, and even more preferably 35% to 75%. By setting the exposed area ratio EA of the pressure-phase transition layer to 5% or more, excessive reduction in adhesive force is suppressed at the edges of the printed material located in the corresponding outer edge, thereby preventing edge peeling. By setting the exposed area ratio EA of the pressure-transition layer to 95 or less, edge tearing that occurs when the pressure-bonded surface of the printed material is peeled off is further suppressed.

[0037] The measurement of the exposed area ratio of the pressure phase transition layer is as follows: The pressure-transition layer is observed using a laser microscope or scanning electron microscope (SEM), the exposed portion of the pressure-transition layer is calculated by image analysis, and the area ratio of the exposed portion of the pressure-transition layer to the area of ​​the observation field (0.5 mm × 0.5 mm) is calculated. In this way, the percentage of exposed pressure-phase transition layer per unit area (0.5 mm × 0.5 mm) in the target region is determined. This operation is performed at 10 locations in the target region, and the average value is calculated.

[0038] (Width of outer edge E) In the printed material according to this embodiment, the width of the outer edge E is 5.0 mm. In the outer edge E, the width of the region where the exposure area ratio of the pressure phase transition layer is smaller than the exposure area ratio IA of the pressure phase transition layer in the central part I of the bonding surface (see "D" in Figures 1 and 2) is preferably 0.5 mm or more and 5.0 mm or less, more preferably 1.0 mm or more and 5.0 mm or less, and even more preferably 2.0 mm or more and 4.0 mm or less. By making the width of the region where the exposed area ratio of the pressure phase transition layer is smaller than the exposed area ratio IA of the pressure phase transition layer in the central part I of the bonding surface 0.5 mm or more (especially 1.0 mm or more), a region that suppresses the increase in bonding force is secured, and furthermore, edge tearing that occurs when the bonding surface of the printed material is peeled off is suppressed. By limiting the width of the region where the exposed area ratio of the pressure-phase transition layer is smaller than the exposed area ratio IA of the pressure-phase transition layer in the central part I of the bonding surface to 5 mm or less, the occurrence of areas where the bonding force is excessively reduced is suppressed, and peeling of the edges of the printed material is inhibited. Here, the width of the outer edge E is the length along the direction perpendicular to the unfolded object.

[0039] (Formation of the pressure-phase transition layer at the outer edge E) In the printed material according to this embodiment, when observing the surface corresponding to the crimped surface of the printed material in the unfolded material, examples of the formation of the pressure phase transition layer at the outer edge E (i.e., the pressure phase transition layer in the region where the exposed area ratio of the pressure phase transition layer is smaller than the exposed area ratio IA of the pressure phase transition layer in the central part I of the crimped surface) include embodiments (1) and (2). In these configurations, the exposed area ratio of the pressure-phase-transition layer at the outer edge E is smaller than the exposed area ratio IA of the pressure-phase-transition layer. As a result, the pressure at the edges of the printed material can be reduced, and tearing at the edges of the printed material can be suppressed. Furthermore, embodiments combining embodiments (1) and (2) are also acceptable.

[0040] -Approach (1)- Embodiment (1): An embodiment having a non-formed region of the pressure phase transition layer at the outer edge E (i.e., an embodiment in which the pressure phase transition layer is patterned and formed at the outer edge B). According to embodiment (1), by providing a region where the pressure-transition layer is not formed, the area to be pressed by the pressure-transition layer is reduced, the pressing force at the edges of the printed material is suppressed, and tearing at the edges of the printed material can be prevented.

[0041] Specifically, embodiment (1) includes, for example, an embodiment in which linear or strip-shaped pressure phase transition layers are arranged (see Figure 3). Examples of arrangement patterns for linear or strip-shaped pressure phase transition layers include the following patterns. (1) A diagonal stripe pattern in which linear or strip-shaped pressure phase transition layers are inclined with respect to the edges of the unfolded object and arranged at intervals along the edges (see Figure 3). (2) A pattern in which linear or strip-shaped pressure phase transition layers are arranged in a grid.

[0042] In Figure 3, PL10 represents the pressure phase transition layer, PL12 represents the region where the pressure phase transition layer is not formed, and E represents the outer edge E.

[0043] Furthermore, embodiment (1) is not limited to an embodiment in which linear or strip-shaped pressure phase transition layers are arranged, but may also be an embodiment in which point-shaped pressure phase transition layers such as circular, elliptical, polygonal, or star-shaped layers are arranged. However, an arrangement of linear or strip-shaped pressure-phase-transition layers is preferable to an arrangement of point-shaped pressure-phase-transition layers in that it suppresses peeling at the edges of the printed material. This is because, in the printed material, the pressure-phase-transition layers are more likely to come into contact with each other on opposing bonding surfaces, thereby suppressing excessive reduction in bonding force.

[0044] -Appearance (2)- Embodiment (2): An embodiment in which, at least a portion of the pressure-phase-transition layer is superimposed on a non-pressure-phase-transition layer in the outer edge E. According to embodiment (2), by providing a non-pressure phase transition layer on top of at least a portion of the pressure phase transition layer, the area of ​​pressure applied by the pressure phase transition layer is reduced, the pressure at the edges of the printed material is suppressed, and tearing at the edges of the printed material can be prevented. The "non-pressure phase transition layer" will be explained in detail later in the section on the printing method.

[0045] Specifically, embodiment (2) includes, for example, an embodiment in which linear or strip-shaped non-pressure phase transition layers are arranged on a uniformly formed pressure phase transition layer (see Figures 4A and 4B). Examples of arrangement patterns for linear or strip-shaped non-pressure phase transition layers include the following patterns. (1) A diagonal stripe pattern in which linear or strip-shaped non-pressure phase transition layers are arranged at an angle to the edges of the unfolded object and spaced apart along the edges (see Figure 4A). (2) A pattern in which linear or strip-shaped non-pressure phase transition layers are arranged in a grid.

[0046] Furthermore, embodiment (2) is not limited to an embodiment in which linear or strip-shaped non-pressure phase transition layers are arranged, but may also be an embodiment in which point-shaped non-pressure phase transition layers such as circular, elliptical, polygonal, or star-shaped layers are arranged.

[0047] In Figures 4A and 4B, PL10 represents the pressure-transition layer, T10 represents the non-pressure-transition layer, E represents the outer edge E, and P represents the recording medium.

[0048] As shown in embodiments (1) and (2), the outer edge E is, for example, a region in which planar pressure-phase-transition layers such as linear, stripe, or dot shapes are arranged, a region in which planar non-pressure-phase-transition layers such as linear, stripe, or dot shapes are arranged on a part of the pressure-phase-transition layer, or a region that is a combination of both, in which the exposed area ratio of the pressure-phase-transition layer is lower than that of the region other than the outer edge E.

[0049] (Format of printed material) The printed materials according to this embodiment include printed materials in which a recording medium is folded and pressed together with the surface on which the image portion and the pressure-transition layer are formed serving as the pressing surface (printed materials that are folded in three ways, such as a Z-fold, and printed materials that are folded in two ways, such as a V-fold), and printed materials in which a recording medium is stacked and pressed together with the surface on which the image portion and the pressure-transition layer are formed serving as the pressing surface. A typical example of a printed material according to this embodiment is a pressure-sensitive postcard.

[0050] [Manufacturing methods and systems for manufacturing printed materials] The method for manufacturing printed materials according to this embodiment is: A pressure phase transition particle application step in which pressure phase transition particles are applied to a recording medium on which an image portion is formed, A fixing step of fixing at least pressure-transition-prone particles onto the recording medium to form a pressure-transition-prone layer, A crimping process in which a recording medium is folded and crimped with the surface on which the image portion and the pressure-transition layer are formed serving as the crimping surface, or a recording medium is stacked and crimped with another recording medium with the surface on which the image portion and the pressure-transition layer are formed serving as the crimping surface, It holds.

[0051] In a first aspect of the method for manufacturing a printed material according to this embodiment, in order to manufacture the printed material according to this embodiment, in the pressure phase transition particle application step, a region to which the pressure phase transition particles are applied is selected on the recording medium, the crimped surfaces of the resulting printed material are separated from each other, and when the surface corresponding to the crimped surface of the printed material in the unfolded material is observed, the exposure area ratio EA of the pressure phase transition layer in the region at a distance of 0.5 mm inward from the edge of the crimped surface at the outer edge E of the position corresponding to at least one of the edges of the edge of the crimped surface reduces the exposure area ratio IA of the pressure phase transition layer in the central part I of the crimped surface.

[0052] On the other hand, a second aspect of the method for manufacturing a printed material according to the present embodiment involves forming a non-pressure phase transition layer on top of at least a portion of the pressure phase transition layer in order to manufacture the printed material according to the present embodiment, and when the crimped surfaces of the resulting printed material are separated and the crimped surface of the printed material is observed in the unfolded material, the exposed area ratio EA of the pressure phase transition layer in the region at a distance of 0.5 mm inward from the edge of the crimped surface at the outer edge of the position corresponding to at least one of the edges of the edge of the crimped surface reduces the exposed area ratio IA of the pressure phase transition layer in the central part I of the crimped surface. In this case, the formation of the non-pressure phase transition layer is preferably carried out using non-pressure phase transition particles.

[0053] Furthermore, the first and second embodiments of the method for manufacturing printed materials according to this embodiment may be combined.

[0054] The method for manufacturing printed materials according to this embodiment is carried out by the printed material manufacturing system according to this embodiment, as shown below. The printing system according to this embodiment is A pressure phase transition particle application unit that contains pressure phase transition particles and applies pressure phase transition particles to a recording medium on which an image area is formed, A fixing unit that fixes at least pressure-transition-prone particles onto a recording medium and forms a pressure-transition-prone layer, A crimping section that uses the surface on which the image portion and the pressure-transition layer are formed as the crimping surface to fold and crimp recording media, or uses the surface on which the image portion and the pressure-transition layer are formed as the crimping surface to crimp one recording media onto another recording media, It is equipped with.

[0055] The image area is the region in which a chromatic image is formed, and is not particularly limited as long as it is an image containing colorants. An example of an image in the visible region (400 nm to 700 nm) is an image in which the average transmittance of light is less than 90%. The average transmittance of light in the chromatic image is preferably less than 50%, more preferably less than 50%, and even more preferably less than 10%. The average transmittance is measured using a spectrophotometer V700 (manufactured by JASCO Corporation).

[0056] "Pressure-induced phase transition layer" and "pressure-induced phase transition particle" refer to a layer and a particle that undergo a phase transition due to pressure, and specifically mean a layer and a particle that satisfy the following equation 1. Formula 1...10℃≦T1-T2 In Equation 1, T1 is the temperature at which the viscosity is 10,000 Pa·s at a pressure of 1 MPa, and T2 is the temperature at which the viscosity is 10,000 Pa·s at a pressure of 10 MPa. The methods for determining temperatures T1 and T2 will be described later.

[0057] The "pressure phase transition layer" and "pressure phase transition particles" preferably contain a styrene-based resin containing styrene and other vinyl monomers as polymerization components, and a (meth)acrylic acid ester-based resin containing at least two types of (meth)acrylic acid esters as polymerization components, wherein the mass ratio of (meth)acrylic acid esters to the total polymerization components is 90% by mass or more, and have at least two glass transition temperatures, and preferably the difference between the lowest and highest glass transition temperatures exhibited by the "pressure phase transition layer" and "pressure phase transition particles" is 30°C or more. The reason is as follows.

[0058] Generally, styrene resins and (meth)acrylic acid ester resins have low compatibility with each other, so it is thought that both resins are contained in the particles in a phase-separated state. Furthermore, when the layer and particles are pressurized, it is thought that the (meth)acrylic acid ester resin, which has a relatively low glass transition temperature, will first fluidize, and this fluidization will spread to the styrene resin, causing both resins to fluidize. In addition, it is thought that when the resins in the layer and particles solidify under reduced pressure after fluidization due to pressurization, they will once again form a phase-separated state due to their low compatibility. (Meth)acrylic acid ester resins containing at least two types of (meth)acrylic acid esters as polymerization components are presumed to have a lower degree of molecular alignment in the solid state compared to (meth)acrylic acid ester homopolymers, because at least two types of ester groups are bonded to the main chain, and therefore are more easily fluidized under pressure. Furthermore, if the mass percentage of (meth)acrylic acid esters in the total polymerization components is 90% by mass or more, at least two types of ester groups will be present at a high density, resulting in an even lower degree of molecular alignment in the solid state, and therefore is presumed to be even more easily fluidized under pressure. Therefore, it is presumed that the "pressure-induced phase transition layer" and "pressure-induced phase transition particles" in the above configuration are easily fluidized by pressure, that is, they are prone to phase transitions due to pressure. Furthermore, (meth)acrylic acid ester resins containing at least two types of (meth)acrylic acid esters as polymerization components, with the mass ratio of (meth)acrylic acid esters to the total polymerization components being 90% by mass or more, are presumed to exhibit a low degree of molecular alignment even when solidified again, resulting in minimal phase separation with styrene-based resins. The smaller the phase separation between styrene-based resins and (meth)acrylic acid ester resins, the more uniform the state of the fixing surface on the object to be fixed, and the better the adhesion properties when compressed. Therefore, it is presumed that the "pressure phase transition layer" and "pressure phase transition particles" exhibit excellent adhesion properties through compression.

[0059] The following describes each step of the printing method according to this embodiment, along with each means of the printing system according to this embodiment.

[0060] <Pressure-induced phase transition particle impregnation process and pressure-induced phase transition particle impregnation unit> In the application process, pressure phase transition particles are applied to the recording medium on which the image portion is formed in the pressure phase transition particle application unit (hereinafter also referred to as the "application unit"). There are no particular restrictions on the means for applying pressure-phase transition particles in the application section; any means capable of applying pressure-phase transition particles to the surface of the recording medium in a desired amount and at a desired application position is acceptable. Specifically, methods for imparting pressure-phase-transition particles include a spraying method in which pressure-phase-transition particles are sprayed, a coating method in which pressure-phase-transition particles are applied, and an electrophotographic method using pressure-phase-transition particles as toner.

[0061] (Position for imparting pressure-induced phase transition particles) The pressure-transition-prone particles may be placed over the entire recording medium or in a portion of it. The pressure-transition-prone particles are applied to the recording medium in two locations: the image portion and the non-image portion of the pressure-sensitive surface of the recording medium. However, when observing the surface corresponding to the crimped surface in the unfolded printed material, the placement of the pressure-transition particles is selected such that the exposure area ratio EA of the pressure-transition layer in the region at a distance of 0.5 mm inward from the edge of the crimped surface, at the outer edge E corresponding to at least one of the edges of the crimped surface, is smaller than the exposure area ratio IA of the pressure-transition layer in the central part I of the crimped surface. Furthermore, if a subsequent process involves forming a non-pressure phase transition layer to impart pressure phase transition particles, it is not necessary to select the position where the pressure phase transition particles are imparted.

[0062] Here, the pressure-transition particles are preferably transparent, as will be described later. Because the pressure-phase-transition particles are transparent, even when the pressure-phase-transition particles are applied to the image portion of the recording medium and a pressure-phase-transition layer is formed, the visibility of the image portion is ensured. Furthermore, "transparent" means that the average light transmittance in the visible region (400 nm to 700 nm) of the region where the pressure-phase-transition particles are fixed is 10% or more, preferably 50% or more, more preferably 80% or more, and even more preferably 90% or more. The above average transmittance is measured using a V700 spectrophotometer (manufactured by JASCO Corporation).

[0063] (State of pressure-induced phase transition particles) The pressure-transition-prone particles may be in a state where their shape is retained, or they may be aggregated into layers. From the viewpoint of obtaining sufficient peel strength (or adhesion due to compression), it is preferable that they be in layers. The layer made of pressure-transition particles may be a continuous layer or a discontinuous layer.

[0064] The amount of pressure-transition-promoting particles to be added is 0.5 g / m², from the viewpoint of obtaining sufficient adhesion through compression. 2 More than 8.0g / m 2 Preferably, it is 1.0 g / m 2 More than 6.0g / m 2 It is more preferable that the following conditions be met: 1.5 g / m 2 More than 5.0g / m 2 The following is even more preferable:

[0065] (Imposition of pressure-induced phase transition particles) As mentioned above, there are no particular restrictions on the application of pressure-transition particles, as long as the pressure-transition particles are applied to the desired location. Specifically, methods such as spraying the pressure-transition particles, coating the pressure-transition particles, and electrophotography using pressure-transition particles as toner can be used. The pressure-transition particles may also be applied by direct dropping onto the recording medium or by roll coating. As long as the pressure-transition particles are applied to the recording medium, the method of application is not particularly limited. Examples of application units for applying pressure-transition-sensitive particles onto a recording medium include, as mentioned above, an application unit that uses a spraying method to spray pressure-transition-sensitive particles, an application unit that uses a coating method to coat pressure-transition-sensitive particles, and an application unit that uses an electrophotographic method to use pressure-transition-sensitive particles as toner.

[0066] The application process by spraying includes, for example, the steps of preparing a dispersion in which pressure-phase-transition particles are dispersed, spraying the dispersion onto a recording medium, and drying the dispersion sprayed onto the recording medium. Furthermore, the application unit using a spraying method includes, for example, a spraying means for spraying a dispersion containing pressure-phase-transition particles onto a recording medium, and a drying means for drying the dispersion sprayed onto the recording medium. Examples of spraying methods include sprayers. Examples of drying methods include hot air blowers, near-infrared heaters, laser irradiation devices, etc.

[0067] The coating method application process includes, for example, a step of coating a recording medium with pressure-transition-sensitive particles. In the coating method, a coating solution in which the pressure-transition-sensitive particles are dispersed may be used. The coating method application process using a coating solution may include, for example, a step of preparing a coating solution in which the pressure-transition-sensitive particles are dispersed, a step of coating the coating solution onto a recording medium, and a step of drying the coating solution applied on the recording medium. Furthermore, the application unit using a coating method includes, for example, a coating means for coating pressure-phase-transition particles onto a recording medium. The application unit using a coating method with a coating liquid may include, for example, a coating means for coating the coating liquid onto a recording medium and a drying means for drying the coating liquid applied on the recording medium. Examples of application methods include rollers.

[0068] The electrophotographic imparting process includes, for example, a charging step of charging the surface of an image holder; an electrostatic image formation step of forming an electrostatic image on the charged surface of the image holder; a developing step of developing the electrostatic image formed on the surface of the image holder as a pressure phase transition particle region using an electrostatic image developer containing pressure phase transition particles; and a transfer step of transferring the pressure phase transition particle region formed on the surface of the image holder to the surface of a recording medium. Furthermore, the electrophotographic imparting unit includes, for example, an image holder, a charging means for charging the surface of the image holder, an electrostatic image forming means for forming an electrostatic image on the charged surface of the image holder, a developing means containing an electrostatic image developer containing pressure phase transition particles, and developing the electrostatic image formed on the surface of the image holder as a pressure phase transition particle region using the electrostatic image developer, and a transfer means for transferring the pressure phase transition particle region formed on the surface of the image holder to the surface of a recording medium.

[0069] The particle application unit using the electrophotographic method may have a cartridge structure (a so-called process cartridge) that is attached to and detached from the particle application device, including the developing means. As a process cartridge, for example, a process cartridge that includes a developing means containing an electrostatic image developer containing pressure phase transition particles and is attached to and detached from the particle application device is preferably used. The electrophotographic application method and application unit may both utilize an electrophotographic image forming method and image forming apparatus, or they may utilize known processes and means employed in electrophotographic image forming methods and image forming apparatuses. Furthermore, the electrophotographic method and application unit may employ an intermediate transfer method. In the intermediate transfer method, for example, the pressure phase transition particle region formed on the surface of the image holder is first transferred to the surface of the intermediate transfer body, and then finally transferred from the surface of the intermediate transfer body to the surface of the recording medium. Furthermore, the electrophotographic method and application unit may include means and processes other than those described above, such as a step and means for cleaning the surface of the image holder, or an apparatus equipped with a means for removing static electricity by irradiating the surface of the image holder with static electricity removal light.

[0070] When using a recording medium with an image portion already formed, pressure-phase-transition particles may be added to the recording medium with the image portion already formed, or the image formation step of forming the image portion on the recording medium and the addition step may be performed continuously. Methods for performing the image formation process and the application process consecutively include, for example, a method in which the application process is performed after the image formation process using an inkjet recording method, and a method in which both the image formation process and the application process are performed using an electrophotographic method. Specifically, for example, a method can be used to form a composite image on the surface of a recording medium using both a colorant for image formation in the image formation process (preferably a colored ink) and pressure-transition particles in the application process.

[0071] <Fixing process and fixing section> In the fixing process, at least pressure-transition-resistant particles are fixed to the recording medium to form a pressure-transition-resistant layer. Specifically, in the fixing process, for example, pressure-transition particles applied to the recording medium are heated in the fixing section. Furthermore, if an unfixed toner image area is formed on the recording medium as the image area, the fixing process may also be a process of fixing the unfixed toner image area together with pressure phase transition particles.

[0072] There are no particular limitations on the means for heating the pressure-transition particles (hereinafter also referred to as "particle heating means"), as any means capable of heating the pressure-transition particles applied to a recording medium formed on a recording medium is acceptable. The means for heating the pressure-phase-transition particles (particle heating means) may be a contact method or a non-contact method. Contact-type particle heating means include, for example, a method in which components such as rolls, belts, and pads are heated and then brought into contact with pressure-transition-prone particles. Non-contact particle heating methods include, for example, passing a recording medium on which a chromatic image has been formed and on which pressure-phase-transition particles have been added through a region heated by a heater, oven, etc., and heating the pressure-phase-transition particles with light irradiated from a halogen lamp, xenon lamp, etc.

[0073] In particular, the fixing process preferably uses a contact-type particle heating means, from the viewpoint of heating the pressure-phase-transition particles while suppressing their movement, detachment, etc. In other words, the particle heating means is preferably a contact-type particle heating means.

[0074] (Heating of pressure-transition particles using a contact method) When heating pressure-transition particles using a contact method, the set temperature of the component that comes into contact with the pressure-transition particles (also called the contact component) should be any temperature that can plasticize the pressure-transition particles. However, from the viewpoint of heating efficiency of the pressure-transition particles, it is preferable that the temperature be between 120°C and 250°C, more preferably between 130°C and 200°C, and even more preferably between 150°C and 180°C. Here, the set temperature of the contact member refers to the target value of the surface temperature of the contact member that comes into contact with the pressure-phase-transition particles. The contact member is not particularly limited as long as it is a member having a surface heated to the above-mentioned set temperature, and examples include rolls, belts, pads, etc.

[0075] The fixing process is preferably a process of heating and pressurizing the pressure-phase-transition particles. By heating and pressurizing pressure-transition-prone particles, smoothness can be imparted to the surface of the pressure-transition-prone particles (for example, the surface of the pressure-transition-prone particle layer). The pressure applied to the pressure-transition-sensitive particles during the fixing process can be, for example, the pressure applied by an electrophotographic fixing method.

[0076] The following are examples of means (also called heating and pressurizing members) for heating and pressurizing pressure-transition-sensitive particles. Specifically, examples include: a heated and pressurized roll pair consisting of two contacting roll pairs, where heat is applied from at least one of the rolls, and a recording medium on which a chromatic image is formed and pressure-transition-prone particles are applied is inserted between the roll pair to apply heat and pressure; a heated and pressurized member consisting of a roll and a belt in contact, where heat is applied from at least one of the roll and the belt, and a recording medium on which a chromatic image is formed and pressure-transition-prone particles are applied is inserted between these members to apply heat and pressure; and a heated and pressurized belt pair consisting of two contacting belt pairs, where heat is applied from at least one of the belts, and a recording medium on which a chromatic image is formed and pressure-transition-prone particles are applied is inserted between the belt pair to apply heat and pressure.

[0077] <Crimping process and crimping section> In the crimping process, the recording medium is folded and crimped with the surface on which the image portion and the pressure-transitionable layer are formed serving as the crimping surface, or another recording medium is placed on top of the recording medium and crimped with the surface on which the image portion and the pressure-transitionable layer are formed serving as the crimping surface. Hereinafter, the recording medium on which the image portion and the pressure-transitionable layer are formed will also be referred to as the "post-application recording medium."

[0078] Specifically, in the crimping process, a laminate formed by folding a recording medium on which the image portion and the pressure-transition granular layer are formed (i.e., the post-processing recording medium) with a pressure-transition layer interposed therebetween, or a laminate formed by stacking the post-processing recording medium on which the image portion and the pressure-transition layer are formed with another recording medium with a pressure-transition layer interposed therebetween, is pressed in the thickness direction. The folded form of the recording medium after application can be, for example, a bi-fold, a tri-fold, or a quad-fold, and it may also be a form in which only a part of the recording medium is folded. In this case, the pressure phase transition layer fixed in the fixing process is positioned on two opposing surfaces of the recording medium after application. The form in which the applied recording medium and the other recording medium overlap can be, for example, a form in which one other recording medium is placed on top of the applied recording medium, or a form in which one other recording medium is placed on multiple locations on the applied recording medium. Here, the other recording medium may be a recording medium on which an image has been formed in advance on one or both sides, a recording medium on which no image has been formed, or a pre-made pressure-sensitive printed material. In this case, the pressure-phase-transition particles fixed in the fixing process are arranged on the two opposing surfaces of the applied recording medium and the other recording medium.

[0079] There are no particular restrictions on the means for pressurizing the laminate (laminated laminate pressurizing means). Any means capable of pressurizing the laminate in the thickness direction is acceptable. This may include means for passing the laminate between spaced-apart pairs of rolls, or means for pressurizing the laminate using a press machine or the like.

[0080] In particular, the crimping process is preferably a process in which the laminate is inserted between a pair of rolls spaced apart by an interval C, and the laminate is pressed in the thickness direction. In other words, the laminate pressing means is preferably a means of inserting the laminate between a pair of rolls spaced apart by an interval C and pressing the laminate in the thickness direction. Here, the spacing C can be appropriately determined based on the thickness of the laminate being pressed, from the viewpoint of obtaining the desired peel strength (or adhesive properties due to compression). For example, 0.01 mm or more and 0.40 mm or less is preferred, 0.05 mm or more and 0.30 mm or less is more preferred, and 0.10 mm or more and 0.25 mm or less is even more preferred.

[0081] (Conditions for pressurization) The pressure applied in the thickness direction of the laminate (hereinafter also referred to as "compression pressure") is preferably 48 MPa to 120 MPa at maximum pressure, more preferably 60 MPa to 110 MPa, and even more preferably 80 MPa to 100 MPa. A crimping pressure of 48 MPa or higher makes it easier to achieve sufficient crimping performance. Conversely, a crimping pressure of 120 MPa or lower helps to suppress tearing, deformation, and other damage to the recording medium during pressurization. The compression pressure is measured using a commercially available pressure measuring film. Specifically, Fujifilm Corporation's pressure measuring film, Prescale, is a suitable example. The maximum pressure mentioned above represents the maximum value of the pressure change while pressure is applied to the laminate by the laminate pressurizing means.

[0082] Commercially available equipment may be used as the means for pressurizing the laminate. Specifically, examples include PRESSLE LEADA, PRESSLE CORE, and PRESSLE Bee from Toppan Forms Co., Ltd., and PS-500H, PS-500, EX-4100WI, EX-4100W, EX-4100 / 4150, and PS-100 from Duplo Seiki Co., Ltd.

[0083] The crimping process may be performed without heating, or with heating. In other words, the laminate pressurizing means may not include a heating means and may pressurize the laminate without heating, or it may include a heating means and pressurize the laminate while heating.

[0084] The method for manufacturing printed materials according to this embodiment may include other steps besides the application step, fixing step, and pressure application step. Other processes include forming an image portion on the recording medium before applying pressure-transition particles, and cutting the recording medium after the fixing process or the laminate after the crimping process to the desired size.

[0085] When forming a non-pressure phase transition layer on at least a portion of the pressure phase transition layer, for example, after the pressure phase transition particle application step and before the fixing step, non-pressure phase transition particles are applied to at least a portion of the pressure phase transition particle application location, and then the fixing step and the crimping step are carried out. As a result, during the fixing step, a non-pressure phase transition layer is formed on at least a portion of the pressure phase transition layer. Alternatively, after the fixing process but before the crimping process, non-pressure phase-transition particles may be applied to at least a portion of the pressure phase-transition layer, and then the non-pressure phase-transition particles may be fixed. In this way, a non-pressure phase-transition layer is formed on at least a portion of the pressure phase-transition layer.

[0086] Here, "non-pressure phase transition layer" and "non-pressure phase transition particle" refer to layers and particles that do not undergo a phase transition due to pressure, and specifically, layers and particles that do not satisfy the above equation 1. Furthermore, the "non-pressure phase transition layer" and the "non-pressure phase transition particles" are preferably thermoplastic.

[0087] Specifically, non-pressure phase transition particles are used, such as electrostatic image developing toner (so-called thermal fixing toner) that can be fixed by heating and pressurizing. Furthermore, it is preferable that the toner used as the non-pressure phase transition particle be a transparent electrostatic image developing toner. In other words, the non-pressure phase transition layer can be used, for example, toner for electrostatic image development (specifically, transparent toner for electrostatic image development). The definition of "transparent" is the same as that of pressure-phase-transition particles.

[0088] One method for imparting non-pressure phase transition particles is electrophotography.

[0089] <Examples of manufacturing systems and methods> The following describes an example of a printing system according to this embodiment and explains the method for manufacturing printed materials according to this embodiment, but this embodiment is not limited thereto.

[0090] Figure 5 is a schematic diagram showing an example of a printing system according to this embodiment. The printing system shown in Figure 5 comprises a printing means 500 that simultaneously performs the formation of an image portion on a recording medium using an inkjet method and the application of pressure-phase-transition particles, and a pressing means 200 located downstream of the printing means 500. The arrows indicate the transport direction of the recording medium.

[0091] The printing means 500 includes, as an example of an image forming unit, an inkjet recording head 520 that ejects ink droplets onto the recording medium P to form an image. Downstream from the inkjet recording head 520 in the transport direction of the recording medium P (in the direction of the arrow in the figure), a particle application device 518 is arranged to apply pressure phase transition particles 516 to the surface of the recording medium P, as an example of an application unit that applies pressure phase transition particles to the recording medium by coating.

[0092] Furthermore, the printing means 500 includes a recording medium storage unit (not shown) for storing the recording medium P, a transport unit (not shown) for transporting the recording medium P stored in the recording medium storage unit, a fixing device 564 for fixing ink droplets and pressure phase transition particles 516 applied to the recording medium P onto the recording medium P, and a recording medium discharge unit (not shown) from which the recording medium P on which the ink droplets and pressure phase transition particles 516 have been fixed by the fixing device 564 is discharged.

[0093] The fixing device 564 includes a heating roll 564A that incorporates a heating source, and a pressure roll 564B that is provided opposite to the heating roll 564A.

[0094] The particle application device 518 is a device that supplies pressure-phase-transition particles 516 to the surface of the recording medium P, thereby forming a pressure-phase-transition particle region 516A on the surface of the recording medium P. The particle application device 518 is provided with a supply roll 518A in the portion facing the recording medium P, and applies pressure-phase-transition particles 516 to the corresponding coating area. In the particle application device 518, pressure-transition particles 516 are supplied to the supply roll 518A (conductive roll), and the amount of pressure-transition particles 516 applied to the recording medium P (i.e., the thickness of the layer of pressure-transition particle region 516A applied in layers on the recording medium P) is adjusted.

[0095] The inkjet recording head 520 consists of an inkjet recording head 520Y that ejects yellow ink droplets from its nozzles, an inkjet recording head 520M that ejects magenta ink droplets from its nozzles, an inkjet recording head 520C that ejects cyan ink droplets from its nozzles, and an inkjet recording head 520K that ejects black ink droplets from its nozzles. These inkjet recording heads 520 are driven by piezoelectric (piezo) or thermal methods. The inkjet recording head 520 may be a recording head that records an image by ejecting droplets onto the recording medium P without moving in a direction intersecting the transport direction of the recording medium P, while having a recording width greater than or equal to the recording area, or it may be a recording head that records an image by ejecting droplets onto the recording medium P while moving in a direction intersecting the transport direction of the recording medium P. Furthermore, while both water-based and oil-based inks can be used for the ink ejected by the inkjet recording head 520, water-based inks are preferred for environmental reasons. Water-based inks contain recording materials such as colorants, as well as an ink solvent (e.g., water, water-soluble organic solvent). In addition, other additives may be included as needed.

[0096] In the printing means 500, first the recording medium P is transported from the recording medium storage unit by the transport unit to the position of the inkjet recording head 520, where ink droplets of each color are applied to the recording medium P by the inkjet recording head 520, forming an image. Subsequently, the recording medium P with the image formed is transported by the transport unit to the position of the particle application device 518, where pressure phase transition particles 516 are applied to the recording medium P by the particle application device 518, forming a pressure phase transition particle region 516A. The recording medium P, on which the image area and the pressure-phase-transition particle region 516A are formed, is subsequently transported to a fixing device 564 (an example of a fixing unit). The pressure applied to the recording medium P by the fixing device 564 may be lower than the pressure applied to the recording medium P by the pressurizing device 230, and is preferably 0.2 MPa to 1 MPa. The surface temperature of the recording medium P when heated by the heating roll 564A of the fixing device 564 is preferably 150°C to 220°C, more preferably 155°C to 210°C, and even more preferably 160°C to 200°C.

[0097] As described above, the recording medium P becomes a post-processing recording medium P1 in which an image portion is formed and pressure-phase-transition-sensitive particles are applied, by passing through the printing means 500. Next, the recording medium P1 after the data has been added is transported toward the crimping means 200.

[0098] In the printing system according to this embodiment, the printing means 500 and the pressing means 200 may be in close proximity or separated from each other. If the printing means 500 and the crimping means 200 are separated, they are connected, for example, by a transport means (e.g., a belt conveyor) that transports the recording medium P1 after application.

[0099] The crimping means 200 comprises a folding device 220 and a pressing device 230, and is a means for folding and crimping the recording medium P1 after application.

[0100] The folding device 220 folds the post-processing medium P1 that passes through the device to produce a stacked recording medium, i.e., a laminate P2. Furthermore, in the stacked recording media (i.e., laminate), pressure-phase-transition particles applied by the printing means 500 are arranged on at least a portion of at least one of the two opposing surfaces of the recording media.

[0101] The crimping means 200 may include a stacking device for stacking the recording medium after application with another recording medium, instead of a folding device 220. In the recording medium obtained by the stacking device, i.e., the laminate, pressure-phase-transition particles applied by the printing means 500 are arranged on at least a portion of at least one of the two opposing surfaces of the applied recording medium and another recording medium.

[0102] The laminated body P2, having exited the folding device 220 (or stacking device), is transported toward the pressurizing device 230.

[0103] The pressurizing device 230 comprises, for example, a pair of pressurizing members (i.e., pressurizing rolls 231 and 232). The pressurizing rolls 231 and 232 are spaced apart, for example, by a gap C, and pressure is applied to the thickness direction of the laminate P2 by passing the laminate P2 between the pair of rolls. The pair of pressurizing members provided in the pressurizing device 230 is not limited to a combination of pressurizing rolls, but may also be a combination of pressurizing rolls and pressurizing belts, or a combination of pressurizing belts.

[0104] The pressurizing device 230 may or may not have a heat source (e.g., a halogen heater) inside for heating the laminate P2. If the pressurizing device 230 has a heat source inside, the surface temperature of the laminate P2 when heated by the heat source is preferably 30°C to 120°C, more preferably 40°C to 100°C, and even more preferably 50°C to 90°C. Note that if the pressurizing device 230 does not have a heat source inside, it is not ruled out that the temperature inside the pressurizing device 230 may exceed the ambient temperature due to heat generated by the motor or other components of the pressurizing device 230.

[0105] When pressure is applied to the laminate P2 as it passes through the pressurizing device 230, the overlapping surfaces are fixed together by fluidized pressure-transition particles, and a crimped printed material P3 is produced. The resulting pressure-sensitive printed material P3 has its opposing surfaces partially or completely fixed to each other.

[0106] The completed pressure-pressed printed material P3 is discharged from the pressure device 230.

[0107] The first form of the pressure-sensitive printed material P3 is a pressure-sensitive printed material in which folded recording media are pressed together on opposing surfaces by pressure-transition particles. The pressure-sensitive printed material P3 is produced by a printed material manufacturing system equipped with a folding device 220.

[0108] The second form of the pressure-sensitive printed material P3 is a pressure-sensitive printed material in which multiple overlapping recording media are pressed together on opposing surfaces by pressure-transition-sensitive particles. The pressure-sensitive printed material P3 is manufactured by a pressure-sensitive printed material manufacturing system equipped with a stacking device.

[0109] The printing manufacturing system according to this embodiment is not limited to a system that continuously transports the laminate P2 from the folding device 220 (or stacking device) to the pressurizing device 230. The printing production system according to this embodiment may also be a device that stores the laminate P2 after it exits the folding device 220 (or stacking device), and after the amount of stored laminate P2 reaches a predetermined amount, transports the laminate P2 to the pressurizing device 230.

[0110] In the printing manufacturing system according to this embodiment, the folding device 220 (or stacking device) and the pressing device 230 may be located in close proximity or at a distance from each other. When the folding device 220 (or stacking device) and the pressing device 230 are at a distance from each other, they may be connected by, for example, a conveying means (e.g., a belt conveyor) that transports the laminate P2.

[0111] Furthermore, the printing system according to this embodiment may include cutting means for cutting the recording medium to predetermined dimensions. Examples of cutting means include: cutting means positioned between the printing means 300 and the crimping means 200 to cut off a portion of the recording medium P1 after application where pressure-transition particles are not present; cutting means positioned between the folding device 220 and the pressurizing device 230 to cut off a portion of the laminate P2 where pressure-transition particles are not present; cutting means positioned downstream of the crimping means 200 to cut off a portion of the crimped print P3 where pressure-transition particles have not been fixed; and so on. Furthermore, depending on the cutting method, a portion of the region where the pressure-phase-transition particles are located may be cut off.

[0112] The printing production system according to this embodiment is not limited to a sheet-fed apparatus. The printing production system according to this embodiment may be an apparatus that performs a placement process and a pressing process on a long recording medium to form a long pressed printed material, and then cuts the long pressed printed material to predetermined dimensions.

[0113] Figure 6 is a schematic diagram showing an example of a printing system according to this embodiment. The printing system shown in Figure 6 comprises a printing means 300 that performs the formation of an image portion on a recording medium and the application of pressure-phase-transition particles in a single operation, and a crimping means 200 located downstream of the printing means 300.

[0114] The printing means 300 is a five-tandem and intermediate transfer printing method. The printing means 300 includes a unit 10S that applies transparent toner (S) as non-pressure phase transition particles (S) to form a transparent image on a portion of the pressure phase transition layer, a unit 10T that applies pressure phase transition particles (T), and units 10Y, 10M, 10C, and 10K that form yellow (Y), magenta (M), cyan (C), and black (K) color images, respectively. Unit 10S is a means for forming a transparent image (non-pressure phase transition layer) on a recording medium P (specifically, on a part of the pressure phase transition layer to be formed) using a developer containing transparent toner. Unit 10T is a particle application means (i.e., application unit) that applies pressure phase transition particles onto the recording medium P using a developer containing pressure phase transition particles. Units 10Y, 10M, 10C, and 10K are means for forming a colored image (i.e., an image portion) on the recording medium P using a developer containing colored toner. Units 10S, 10T, 10Y, 10M, 10C, and 10K employ an electrophotographic method.

[0115] Units 10S, 10T, 10Y, 10M, 10C, and 10K are arranged side by side, spaced apart from each other in the horizontal direction. Units 10S, 10T, 10Y, 10M, 10C, and 10K may also be process cartridges that can be attached to and detached from the printing means 300.

[0116] Below units 10S, 10T, 10Y, 10M, 10C, and 10K, an intermediate transfer belt (an example of an intermediate transfer body) 20 extends through each unit. The intermediate transfer belt 20 is wound around a drive roll 22, a support roll 23, and an opposing roll 24 that are in contact with the inner surface of the intermediate transfer belt 20, and is configured to travel in the direction from unit 10S to unit 10K. On the image holding surface side of the intermediate transfer belt 20, an intermediate transfer body cleaning device 21 is provided opposite the drive roll 22.

[0117] Units 10S, 10T, 10Y, 10M, 10C, and 10K are each equipped with a developing device (an example of a developing means) 4S, 4T, 4Y, 4M, 4C, and 4K, respectively. Each of the developing devices 4S, 4T, 4Y, 4M, 4C, and 4K is supplied with transparent toner, pressure-transition particles, yellow toner, magenta toner, cyan toner, and black toner, which are contained in cartridges 8S, 8T, 8Y, 8M, 8C, and 8K.

[0118] Since units 10S, 10T, 10Y, 10M, 10C, and 10K have equivalent configurations and operations, unit 10T, which imparts pressure-phase-transition particles to the recording medium, will be described as a representative example.

[0119] Unit 10T has a photoreceptor (an example of an image holder) 1T. Around the photoreceptor 1T are, in order, a charging roll (an example of a charging means) 2T for charging the surface of the photoreceptor 1T, an exposure device (an example of a static charge image forming means) 3T for exposing the charged surface of the photoreceptor 1T with a laser beam to form a static charge image, a developing device (an example of a developing means) 4T for developing the static charge image by supplying pressure phase transition particles to the static charge image to form a pressure phase transition particle region, a primary transfer roll (an example of a primary transfer means) 5T for transferring the pressure phase transition particle region formed by development onto the intermediate transfer belt 20, and a photoreceptor cleaning device (an example of a cleaning means) 6T for removing pressure phase transition particles remaining on the surface of the photoreceptor 1T after primary transfer. The primary transfer roll 5T is located inside the intermediate transfer belt 20 and is positioned opposite the photoreceptor 1T.

[0120] The following describes the operation of applying pressure-transition particles and forming an image on the recording medium P, using the operation of unit 10T as an example. First, the surface of the photoreceptor 1T is charged by the charging roll 2T. The exposure apparatus 3T irradiates the charged surface of the photoreceptor 1T with a laser beam according to image data sent from a control unit (not shown). As a result, an electrostatic charge image, which will be the region for imparting pressure-phase-transition particles, is formed on the surface of the photoreceptor 1T.

[0121] The electrostatic charge image formed on the photoreceptor 1T rotates as the photoreceptor 1T moves to the development position. At the development position, the electrostatic charge image on the photoreceptor 1T is developed by the development device 4T and becomes a pressure phase transition particle region.

[0122] The developing unit 4T contains a developer containing at least pressure-transition particles and a carrier. The pressure-transition particles are triboelectrically charged by being agitated together with the carrier inside the developing unit 4T and are held on the developer roll. As the surface of the photoreceptor 1T passes through the developing unit 4T, the pressure-transition particles electrostatically adhere to the electrostatic charge image on the surface of the photoreceptor 1T, and the electrostatic charge image is developed by the pressure-transition particles, forming a pressure-transition particle region. The photoreceptor 1T, on which the pressure-transition particle region has been formed, continues to move, and the pressure-transition particle region formed on the photoreceptor 1T is transported to the primary transfer position.

[0123] When the pressure-transition particle region on the photoreceptor 1T is transported to the primary transfer position, a primary transfer bias is applied to the primary transfer roll 5T, and an electrostatic force from the photoreceptor 1T toward the primary transfer roll 5T acts on the pressure-transition particle region, transferring the pressure-transition particle region on the photoreceptor 1T onto the intermediate transfer belt 20. The pressure-transition particles remaining on the photoreceptor 1T are removed and recovered by the photoreceptor cleaning device 6T. The photoreceptor cleaning device 6T is, for example, a cleaning blade, a cleaning brush, etc., and is preferably a cleaning brush.

[0124] In units 10S, 10Y, 10M, 10C, and 10K, the same operation as in unit 10T is performed using a developer containing colored toner. The intermediate transfer belt 20, on which the pressure phase transition particle region was transferred in unit 10T, passes through units 10Y, 10M, 10C, and 10K in sequence, and the toner images of each color are superimposed onto the intermediate transfer belt 20. Furthermore, when forming a transparent image on a portion of the pressure phase transition layer, the intermediate transfer body 20, onto which the transparent toner image has been transferred in unit 10S, passes sequentially through units 10T, 10Y, 10M, 10C, and 10K, and the pressure phase transition particle region and toner images of each color are multiple times transferred onto the intermediate transfer belt 20.

[0125] Through units 10S, 10T, 10Y, 10M, 10C, and 10K, the intermediate transfer belt 20, on which the transparent toner image, the pressure-transition particle region, and the toner images of each of the four colors have been multiple-transferred, proceeds to a secondary transfer section consisting of the intermediate transfer belt 20, a counter roll 24 in contact with the inner surface of the intermediate transfer belt, and a secondary transfer roll (an example of a secondary transfer means) 26 positioned on the image-holding side of the intermediate transfer belt 20. Meanwhile, the recording medium P is fed through a supply mechanism into the gap where the secondary transfer roll 26 and the intermediate transfer belt 20 are in contact, and a secondary transfer bias is applied to the counter roll 24. At this time, an electrostatic force from the intermediate transfer belt 20 toward the recording medium P acts on the transparent toner image, the pressure-transition particle region, and the colored toner image, and the transparent toner image, the pressure-transition particle region, and the colored toner image on the intermediate transfer belt 20 are transferred onto the recording medium P.

[0126] The recording medium P onto which the transparent toner image, the pressure-phase-transition particle region, and the colored toner image have been transferred is transported to a heating device (an example of a particle heating means) 28, which is an example of a fixing unit. When heated by the heating device 28, the transparent toner image and the colored toner image are thermally fixed onto the recording medium P, and the pressure-phase-transition particle region is heated, promoting the plasticization of the pressure-phase-transition particles. The heating device 28 is preferably a device that applies pressure along with heating (also called a heating and pressurizing device) from the viewpoint of suppressing the detachment of pressure-transition-prone particles from the recording medium P, improving the fixation of colored toner to the recording medium P, and promoting the plasticization of pressure-transition-prone particles. If the heating device 28 is a heating and pressurizing device, it is preferable to include a pair of rolls that are equipped with a heating source such as a halogen heater and that come into contact with the pressure-transition particle region and the toner image on the recording medium P to heat the pressure-transition particle region and the toner image. As the recording medium having the transparent toner image, the pressure-transition particle region and the colored toner image passes between these two rolls, the transparent toner image and the colored toner image are thermally fixed onto the recording medium P, and the pressure-transition particle region is heated, promoting the plasticization of the pressure-transition particles.

[0127] As described above, the recording medium P becomes a post-processing recording medium P4 after passing through the printing means 300, in which an image area is formed and pressure-transition-sensitive particles (i.e., a pressure-transition-sensitive layer) is applied. Furthermore, if a transparent toner image is formed in unit 10S, the post-processing recording medium P4 becomes one in which an image area is formed, pressure-transition-sensitive particles (i.e., a pressure-transition-sensitive layer) is applied, and a transparent image is formed on a portion of the pressure-transition-sensitive particles (i.e., the pressure-transition-sensitive layer). Next, the recording medium P4 after the data has been added is transported toward the crimping means 200.

[0128] In the printing system according to this embodiment, the printing means 300 and the pressing means 200 may be located in close proximity or separated from each other. If the printing means 300 and the crimping means 200 are separated, they are connected, for example, by a transport means (e.g., a belt conveyor) that transports the recording medium P4 after application.

[0129] The crimping means 200 shown in Figure 6, similar to the crimping means 200 shown in Figure 5, comprises a folding device 220 and a pressing device 230, and is a means for crimping a laminate P5 obtained by folding the post-applied recording medium P4 to obtain a crimped printed material P6. In the printing manufacturing system shown in Figure 6, the same type of crimping means 200 as the crimping means 200 in the printing manufacturing system shown in Figure 5 is used.

[0130] <Pressure phase transition layer and pressure phase transition particles> The details of the pressure-phase-transition layer and pressure-phase-transition particles according to this embodiment will be described below. Since the pressure-transition layer according to this embodiment is formed by the pressure-transition particles according to this embodiment, only the pressure-transition particles according to this embodiment will be described below.

[0131] The pressure-phase-transition particles according to this embodiment include at least a mother particle and optionally an external additive. The parent particles included in the pressure-phase-transition particles are preferably particles that have at least two glass transition temperatures, and the difference between the lowest and highest glass transition temperatures is 30°C or more.

[0132] [Mother particle] (Binding resin) The mother particles preferably contain a styrene-based resin and a meth)acrylic acid ester-based resin as the binder resin. In particular, the mother particles preferably contain, as a binder resin, a styrene-based resin containing styrene and other vinyl monomers as polymerization components, and a (meth)acrylic acid ester-based resin containing at least two types of (meth)acrylic acid esters as polymerization components, wherein the mass ratio of (meth)acrylic acid esters to the total polymerization components is 90% by mass or more. Hereinafter, "styrene-based resins containing styrene and other vinyl monomers as polymerization components" will also be referred to as "specific styrene-based resins," and "(meth)acrylic acid ester-based resins containing at least two types of (meth)acrylic acid esters as polymerization components, with the mass ratio of (meth)acrylic acid esters to the total polymerization components being 90% by mass or more" will also be referred to as "specific (meth)acrylic acid ester-based resins."

[0133] From the viewpoint of maintaining adhesion through compression, it is preferable that the mother particles contain a higher amount of specific styrene-based resin than the amount of specific (meth)acrylic acid ester resin. The amount of specific styrene-based resin is preferably 55% to 80% by mass, more preferably 60% to 75% by mass, and even more preferably 65% ​​to 70% by mass, relative to the total amount of specific styrene-based resin and specific (meth)acrylic acid ester resin.

[0134] -Specific styrene-based resins- The mother particles constituting the pressure-phase-transition particles contain a specific styrene-based resin that includes styrene and other vinyl monomers as polymerization components.

[0135] The mass percentage of styrene in the total polymerization components of a specific styrene-based resin is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 75% by mass or more, from the viewpoint of suppressing the fluidization of pressure-transition-sensitive particles in the unpressurized state. The mass percentage of styrene in the total polymerization components of a specific styrene-based resin is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less, from the viewpoint of forming pressure-transition-resistant particles that are prone to phase transition under pressure. In other words, the mass percentage of styrene in the total polymerization components of the specific styrene-based resin is preferably 60% by mass or more and 95% by mass or less.

[0136] Examples of vinyl monomers other than styrene (hereinafter also referred to as "other vinyl monomers") contained in the polymerization components of specific styrene-based resins include styrene monomers, acrylic monomers, and the like.

[0137] Other styrene monomers in vinyl monomers include, for example, vinylnaphthalene; alkyl-substituted styrenes such as α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, and pn-dodecylstyrene; aryl-substituted styrenes such as p-phenylstyrene; alkoxy-substituted styrenes such as p-methoxystyrene; halogen-substituted styrenes such as p-chlorostyrene, 3,4-dichlorostyrene, p-fluorostyrene, and 2,5-difluorostyrene; and nitro-substituted styrenes such as m-nitrostyrene, o-nitrostyrene, and p-nitrostyrene. These styrene monomers may be used individually or in combination of two or more.

[0138] As for other vinyl monomers, at least one acrylic monomer selected from the group consisting of (meth)acrylic acid and (meth)acrylic acid esters is preferred. Examples of (meth)acrylic acid esters include alkyl (meth)acrylates, carboxylated alkyl (meth)acrylates, hydroxylated alkyl (meth)acrylates, alkoxylated alkyl (meth)acrylates, and di(meth)acrylic acid esters. These acrylic monomers may be used individually or in combination of two or more.

[0139] Examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)methacrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and isobornyl (meth)acrylate. Examples of carboxylated alkyl esters of (meth)acrylate include 2-carboxyethyl (meth)acrylate. Examples of hydroxysubstituted alkyl esters of (meth)acrylate include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Examples of alkoxy-substituted alkyl esters of (meth)acrylate include 2-methoxyethyl (meth)acrylate. Examples of di(meth)acrylic acid esters include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, butanediol di(meth)acrylate, pentanediol di(meth)acrylate, hexanediol di(meth)acrylate, nonanediol di(meth)acrylate, and decanediol di(meth)acrylate.

[0140] Examples of (meth)acrylic acid esters include 2-(diethylamino)ethyl (meth)acrylate, benzyl (meth)acrylate, and methoxypolyethylene glycol (meth)acrylate.

[0141] Other vinyl monomers included in the polymerization components of specific styrene-based resins include, in addition to styrene-based monomers and acrylic-based monomers, (meth)acrylonitrile; vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isopropenyl ketone; and olefins such as isoprene, butene, and butadiene.

[0142] In particular styrene-based resins, from the viewpoint of forming pressure-transition particles that are prone to phase transition under pressure, it is preferable that the other vinyl monomers included as polymerization components include (meth)acrylic acid esters, more preferably (meth)acrylate alkyl esters, even more preferably (meth)acrylate alkyl esters having 2 to 10 carbon atoms in the alkyl group, and even more preferably (meth)acrylate alkyl esters having 4 to 8 carbon atoms in the alkyl group. From the viewpoint of forming pressure-transition-resistant particles that readily undergo phase transitions under pressure, it is particularly preferable that the other vinyl monomers included as polymerization components in the specific styrene-based resin include at least one of n-butyl acrylate and 2-ethylhexyl acrylate. From the viewpoint of forming pressure-transition-resistant particles that readily undergo phase transitions under pressure, it is preferable that the specific styrene-based resin and the specific (meth)acrylic acid ester-based resin described later contain the same type of (meth)acrylic acid ester as a polymerization component.

[0143] The mass percentage of (meth)acrylic acid ester in the total polymerization components of the specific styrene-based resin is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less, from the viewpoint of suppressing the fluidization of pressure-transition-prone particles in the unpressurized state. From the viewpoint of forming pressure-transition-prone particles that readily undergo phase transition under pressure, it is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more. The (meth)acrylic acid ester here is preferably an alkyl (meth)acrylic acid ester, more preferably an alkyl (meth)acrylic acid ester with 2 to 10 carbon atoms in the alkyl group, and even more preferably an alkyl (meth)acrylic acid ester with 4 to 8 carbon atoms in the alkyl group.

[0144] The specific styrene-based resin is particularly preferably composed of at least one of n-butyl acrylate and 2-ethylhexyl acrylate as polymerization components. The total amount of n-butyl acrylate and 2-ethylhexyl acrylate in the total polymerization components of the styrene-based resin is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less, from the viewpoint of suppressing the fluidization of particles in the unpressurized state. From the viewpoint of forming pressure-transitionable particles that are prone to phase transition under pressure, it is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more.

[0145] The weight-average molecular weight of the specific styrene-based resin is preferably 3000 or more, more preferably 4000 or more, and even more preferably 5000 or more, from the viewpoint of suppressing the fluidization of pressure-phase-transition-sensitive particles in the unpressurized state. From the viewpoint of forming pressure-phase-transition-sensitive particles that are easily subjected to phase transition by pressure, it is preferably 60000 or less, more preferably 55000 or less, and even more preferably 50000 or less.

[0146] The weight-average molecular weight of the resin is measured by gel permeation chromatography (GPC). GPC molecular weight measurement is performed using a Tosoh HLC-8120GPC instrument, a Tosoh TSKgel SuperHM-M (15 cm) column, and tetrahydrofuran as the solvent. The weight-average molecular weight of the resin is calculated using a molecular weight calibration curve prepared from monodisperse polystyrene standard samples.

[0147] The glass transition temperature of a specific styrene-based resin is preferably 30°C or higher, more preferably 40°C or higher, and even more preferably 50°C or higher, from the viewpoint of suppressing the fluidization of pressure-transition-prone particles in the unpressurized state. From the viewpoint of forming pressure-transition-prone particles that readily undergo phase transition under pressure, it is preferably 110°C or lower, more preferably 100°C or lower, and even more preferably 90°C or lower.

[0148] The glass transition temperature of a resin is determined from the differential scanning calorimetry (DSC) curve obtained by performing differential scanning calorimetry. More specifically, it is determined according to the "extracorporeal glass transition onset temperature" described in JIS K7121:1987 "Method for Measuring Transition Temperatures of Plastics".

[0149] The glass transition temperature of a resin is controlled by the type and polymerization ratio of the polymer components. The glass transition temperature tends to be lower when the density of flexible units such as methylene groups, ethylene groups, and oxyethylene groups in the main chain is high, and higher when the density of rigid units such as aromatic rings and cyclohexane rings in the main chain is high. Furthermore, the glass transition temperature tends to be lower when the density of aliphatic groups in the side chains is high.

[0150] The mass percentage of the specific styrene-based resin in the total number of parent particles is preferably 55% by mass or more, more preferably 60% by mass or more, and even more preferably 65% ​​by mass or more, from the viewpoint of suppressing the fluidization of pressure-transition-prone particles in the unpressurized state, and preferably 80% by mass or less, more preferably 75% by mass or less, and even more preferably 70% by mass or less, from the viewpoint of forming pressure-transition-prone particles that undergo phase transition under pressure.

[0151] -Specific (meth)acrylic acid ester resin- Preferably, the mother particles constituting the pressure-phase-transition particles contain a (meth)acrylic acid ester resin in which at least two types of (meth)acrylic acid esters are included as polymerization components, and the mass ratio of (meth)acrylic acid esters to the total polymerization components is 90% by mass or more.

[0152] The mass percentage of (meth)acrylic acid ester in the total polymerization components of the (meth)acrylic acid ester resin is 90% by mass or more, more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 100% by mass.

[0153] Examples of (meth)acrylic acid esters include alkyl (meth)acrylates, carboxylated alkyl (meth)acrylates, hydroxylated alkyl (meth)acrylates, alkoxylated alkyl (meth)acrylates, and di(meth)acrylic acid esters.

[0154] Examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)methacrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and isobornyl (meth)acrylate. Examples of carboxylated alkyl esters of (meth)acrylate include 2-carboxyethyl (meth)acrylate. Examples of hydroxysubstituted alkyl esters of (meth)acrylate include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Examples of alkoxy-substituted alkyl esters of (meth)acrylate include 2-methoxyethyl (meth)acrylate. Examples of di(meth)acrylic acid esters include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, butanediol di(meth)acrylate, pentanediol di(meth)acrylate, hexanediol di(meth)acrylate, nonanediol di(meth)acrylate, and decanediol di(meth)acrylate.

[0155] Examples of (meth)acrylic acid esters include 2-(diethylamino)ethyl (meth)acrylate, benzyl (meth)acrylate, and methoxypolyethylene glycol (meth)acrylate.

[0156] (Meth)acrylic acid esters may be used individually or in combination of two or more types.

[0157] As for the (meth)acrylic acid ester, alkyl (meth)acrylic acid esters are preferred from the viewpoint of forming pressure-transitionable particles that readily undergo phase transition under pressure and have excellent adhesion under compression, alkyl (meth)acrylic acid esters having 2 to 10 carbon atoms in the alkyl group are more preferred, alkyl (meth)acrylic acid esters having 4 to 8 carbon atoms in the alkyl group are even more preferred, and n-butyl acrylate and 2-ethylhexyl acrylate are particularly preferred. As previously described, it is preferable that the specific (meth)acrylic acid ester resin and the specific styrene resin contain the same type of (meth)acrylic acid ester as a polymerization component, from the viewpoint of forming pressure-transitionable particles that are prone to phase transition under pressure.

[0158] The mass percentage of alkyl (meth)acrylate in the total polymerization components of a specific (meth)acrylic acid ester resin is preferably 90% by mass or more, more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 100% by mass, from the viewpoint of forming pressure-transitionable particles that readily undergo phase transition under pressure and have excellent adhesion properties when compressed. Here, alkyl (meth)acrylate is preferably an alkyl (meth)acrylate having 2 to 10 carbon atoms in the alkyl group, and more preferably an alkyl (meth)acrylate having 4 to 8 carbon atoms in the alkyl group.

[0159] Of the at least two (meth)acrylic acid esters included as polymerization components in a specific (meth)acrylic acid ester resin, the mass ratio of the two most abundant esters is preferably 80:20 to 20:80, more preferably 70:30 to 30:70, and even more preferably 60:40 to 40:60, from the viewpoint of forming pressure-transitionable particles that readily undergo phase transition under pressure and have excellent adhesion properties when compressed.

[0160] In a specific (meth)acrylic acid ester resin, it is preferable that the two (meth)acrylic acid esters that make up the largest mass proportion of at least two (meth)acrylic acid esters included as polymerization components are alkyl (meth)acrylic acid esters. Here, alkyl (meth)acrylic acid esters with 2 to 10 carbon atoms in the alkyl group are preferred, and alkyl (meth)acrylic acid esters with 4 to 8 carbon atoms in the alkyl group are more preferred.

[0161] When the two most abundant of the at least two (meth)acrylic acid esters included as polymerization components in a specific (meth)acrylic acid ester resin are alkyl (meth)acrylic acid esters, the difference in the number of carbon atoms in the alkyl groups of the two alkyl (meth)acrylic acid esters is preferably 1 to 4, more preferably 2 to 4, and even more preferably 3 or 4, from the viewpoint of forming pressure-transitionable particles that are easily transitioned by pressure and have excellent adhesion properties by compression.

[0162] From the viewpoint of forming pressure-transitionable particles that readily undergo phase transition under pressure and exhibit excellent adhesion by compression, the specific (meth)acrylic acid ester resin preferably contains n-butyl acrylate and 2-ethylhexyl acrylate as polymerization components. It is particularly preferable that the two types of (meth)acrylic acid esters that make up the largest mass proportions among the at least two types of (meth)acrylic acid esters included as polymerization components in the (meth)acrylic acid ester resin are n-butyl acrylate and 2-ethylhexyl acrylate. The total amount of n-butyl acrylate and 2-ethylhexyl acrylate in the total polymerization components of the (meth)acrylic acid ester resin is preferably 90% by mass or more, more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 100% by mass.

[0163] The specified (meth)acrylic acid ester resin may contain vinyl monomers other than (meth)acrylic acid esters as polymerization components. Examples of vinyl monomers other than (meth)acrylic acid esters include (meth)acrylic acid; styrene; styrene monomers other than styrene; (meth)acrylonitrile; vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isopropenyl ketone; and olefins such as isoprene, butene, and butadiene. These vinyl monomers may be used individually or in combination of two or more.

[0164] When a specific (meth)acrylic acid ester resin contains a vinyl monomer other than (meth)acrylic acid ester as a polymerization component, at least one of acrylic acid and methacrylic acid is preferred as the vinyl monomer other than (meth)acrylic acid ester, with acrylic acid being more preferred.

[0165] The weight-average molecular weight of the specific (meth)acrylic acid ester resin is preferably 100,000 or more, more preferably 120,000 or more, and even more preferably 150,000 or more, from the viewpoint of suppressing the fluidization of particles in the unpressurized state, and preferably 250,000 or less, more preferably 220,000 or less, and even more preferably 200,000 or less, from the viewpoint of forming particles that are prone to phase transition under pressure.

[0166] The glass transition temperature of a specific (meth)acrylic acid ester resin is preferably 10°C or lower, more preferably 0°C or lower, and even more preferably -10°C or lower, from the viewpoint of forming particles that are easily subjected to phase transition by pressure. From the viewpoint of suppressing the fluidization of particles in the unpressurized state, it is preferably -90°C or higher, more preferably -80°C or higher, and even more preferably -70°C or higher.

[0167] The mass percentage of the specific (meth)acrylic acid ester resin in the total number of parent particles is preferably 20% by mass or more, more preferably 25% by mass or more, and even more preferably 30% by mass or more, from the viewpoint of forming pressure-transitionable particles that are prone to phase transition under pressure. From the viewpoint of suppressing the fluidization of particles in the unpressurized state, it is preferably 45% by mass or less, more preferably 40% by mass or less, and even more preferably 35% by mass or less.

[0168] In this embodiment, the total amount of the specific styrene resin and the specific (meth)acrylic acid ester resin contained in the mother particles is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and even more preferably 100% by mass, relative to the total amount of the mother particles.

[0169] The mother particles may, if necessary, contain, for example, polystyrene; non-vinyl resins such as epoxy resin, polyester resin, polyurethane resin, polyamide resin, cellulose resin, polyether resin, and modified rosin. These resins may be used individually or in combination of two or more types.

[0170] (Other ingredients) The mother particles may contain other components as needed. Other components include colorants (e.g., pigments, dyes), mold release agents (e.g., hydrocarbon waxes; natural waxes such as carnauba wax, rice wax, and candelilla wax; synthetic or mineral / petroleum-based waxes such as montan wax; ester waxes such as fatty acid esters and montanic acid esters), and static charge control agents.

[0171] The pressure-phase-transition particles may contain a coloring agent, to the extent that it does not impair the visibility of the image. From the viewpoint of improving the transparency of the pressure phase transition particles, the less coloring agent content in the mother particles, the better. Specifically, the coloring agent content is preferably 1.0% by mass or less, more preferably 0.1% by mass or less, even more preferably 0.01% by mass or less, and particularly preferably none, relative to the total amount of mother particles.

[0172] Furthermore, the pressure-phase-transition particles may be transparent. In this embodiment, "transparent" means that the average transmittance of light in the visible region (400 nm to 700 nm) of the region to which the pressure phase transition particles are attached is 10% or more, preferably 50% or more, more preferably 80% or more, and even more preferably 90% or more. The above average transmittance is measured using a V700 spectrophotometer (manufactured by JASCO Corporation).

[0173] (Structure of parent particles) The internal structure of the parent particles is preferably a sea-island structure. As for the sea-island structure, a sea-island structure having a sea phase containing one of two or more binding resins and an island phase containing the other resin dispersed in the sea phase is preferred. More specifically, from the viewpoint of being easily subjected to phase transition by pressure, a sea-island structure having a sea phase containing a specific styrene-based resin and an island phase containing a specific (meth)acrylic acid ester resin dispersed in the sea phase is preferred. Details of the specific styrene-based resin contained in the sea phase and the (meth)acrylic acid ester resin contained in the island phase are as previously described. Note that the sea phase may also contain an island phase that does not contain (meth)acrylic acid ester resin.

[0174] When the parent particles have a sea-island structure, the average diameter of the island phase is preferably between 200 nm and 500 nm. If the average diameter of the island phase is 500 nm or less, the parent particles are more likely to undergo a phase transition under pressure, and if the average diameter of the island phase is 200 nm or more, the parent particles have excellent mechanical strength (for example, strength that resists deformation when stirred in a developing chamber). From these viewpoints, the average diameter of the island phase is more preferably between 220 nm and 450 nm, and even more preferably between 250 nm and 400 nm.

[0175] Methods for controlling the average diameter of the island phase in a sea-island structure to the above range include, for example, increasing or decreasing the amount of a specific (meth)acrylic acid ester resin relative to the amount of a specific styrene resin in the mother particle manufacturing method described later, and increasing or decreasing the time of maintaining a high temperature in the process of fusing and uniting aggregated resin particles.

[0176] The confirmation of the sea-island structure and the measurement of the average diameter of the island formation will be carried out by the following method. Pressure-transition particles are embedded in epoxy resin, sections are prepared using a diamond knife, and the prepared sections are stained with osmium tetroxide or ruthenium tetroxide in a desiccator. The stained sections are observed using a scanning electron microscope (SEM). The sea phase and island phase of a sea-island structure are distinguished by the degree of staining of the resin with osmium tetroxide or ruthenium tetroxide, and this is used to confirm the presence or absence of a sea-island structure. 100 island phases are randomly selected from the SEM images, the major axis of each island phase is measured, and the average of the major axes of the 100 is taken as the average diameter.

[0177] The parent particles may be single-layered or core-shell particles having a core and a shell layer covering the core. From the viewpoint of suppressing the fluidization of pressure-transitionable particles in the unpressurized state, the parent particles are preferably core-shell structures.

[0178] When the parent particles have a core-shell structure, it is preferable that the core portion contains a specific styrene-based resin and a specific (meth)acrylic acid ester-based resin, from the viewpoint of being easily subjected to phase transition by pressure. Furthermore, from the viewpoint of suppressing the fluidization of pressure-transition-prone particles in the absence of pressure, it is preferable that the shell layer contains a specific styrene-based resin.

[0179] When the parent particles have a core-shell structure, it is preferable that the core portion has a sea phase containing a specific styrene-based resin and island phases containing a specific (meth)acrylic acid ester resin dispersed in the sea phase. The average diameter of the island phase is preferably within the range described above. Furthermore, in addition to the above configuration of the core portion, it is preferable that the shell layer contains a specific styrene-based resin. In this case, the sea phase and shell layer of the core portion have a continuous structure, and the parent particles are prone to phase transitions under pressure.

[0180] Examples of resins included in the shell layer include polystyrene; epoxy resin, polyester resin, polyurethane resin, polyamide resin, cellulose resin, polyether resin, and non-vinyl resins such as modified rosin. These resins may be used individually or in combination of two or more types.

[0181] The average thickness of the shell layer is preferably 120 nm or more, more preferably 130 nm or more, and even more preferably 140 nm or more, from the viewpoint of suppressing deformation of the parent grains. From the viewpoint of the parent grains being more susceptible to phase transitions under pressure, it is preferably 550 nm or less, more preferably 500 nm or less, and even more preferably 400 nm or less.

[0182] The average thickness of the shell layer is measured by the following method. The particles are embedded in epoxy resin, sections are prepared using a diamond knife or similar tool, and the prepared sections are stained with osmium tetroxide or ruthenium tetroxide in a desiccator. The stained sections are observed using a scanning electron microscope (SEM). Ten parent particle cross-sections are randomly selected from the SEM images, and the thickness of the shell layer is measured at 20 locations for each parent particle. The average value is calculated, and the average value of the 10 parent particles is taken as the average thickness.

[0183] The volume-average particle size (D50v) of the mother particles is preferably 4 μm or larger, more preferably 5 μm or larger, and even more preferably 6 μm or larger, from the viewpoint of ease of handling the mother particles. Furthermore, the volume-average particle size of the mother particles is preferably 15 μm or smaller, more preferably 12 μm or smaller, and even more preferably 10 μm or smaller.

[0184] The volume-average particle size (D50v) of the parent particles is measured using a Coulter Multisizer II (Beckman Coulter) and an aperture with a diameter of 100 μm. 0.5 mg to 50 mg of parent particles are added to 2 mL of a 5% by mass aqueous solution of sodium alkylbenzenesulfonate and dispersed. Then, 100 mL to 150 mL of electrolyte (ISOTON-II, Beckman Coulter) is added, and the mixture is dispersed in an ultrasonic disperser for 1 minute. The resulting dispersion is used as the sample. The particle sizes of 50,000 particles with a diameter of 2 μm to 60 μm in the sample are measured. The volume-average particle size (D50v) is defined as the particle size that accounts for 50% of the cumulative volume-based particle size distribution calculated from the smallest diameter side.

[0185] [External additives] Examples of external additives include inorganic particles. Examples of inorganic particles include SiO2, TiO2, Al2O3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, K2O, Na2O, ZrO2, CaO·SiO2, K2O·(TiO2)n, Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, MgSO4, etc.

[0186] The surface of the inorganic particles used as an external additive should preferably be subjected to a hydrophobic treatment. The hydrophobic treatment can be carried out, for example, by immersing the inorganic particles in a hydrophobic treatment agent. The hydrophobic treatment agent is not particularly limited, but examples include silane-based coupling agents, silicone oil, titanate-based coupling agents, and aluminum-based coupling agents. These may be used individually or in combination of two or more. The amount of the hydrophobic treatment agent is, for example, 1 to 10 parts by mass per 100 parts by mass of inorganic particles.

[0187] Examples of external additives include resin particles (such as polystyrene, polymethyl methacrylate, and melamine resin) and cleaning activators (for example, metal salts of higher fatty acids represented by zinc stearate, and fluorine-based high molecular weight particles).

[0188] The amount of external additive added is preferably 0.01% by mass or more and 5% by mass or less relative to the mother particles, and more preferably 0.01% by mass or more and 2.0% by mass or less.

[0189] [Characteristics of pressure-phase-transition particles] Pressure-transition-sensitive particles have at least two glass transition temperatures, one of which is presumed to be derived from one of the two or more binder resins, and the other from the other of the two or more binder resins. As previously mentioned, when the binder resin includes a specific styrene-based resin and a specific (meth)acrylic acid ester-based resin, one of the glass transition temperatures is presumed to be the glass transition temperature of the specific styrene-based resin, and the other is presumed to be the glass transition temperature of the specific (meth)acrylic acid ester-based resin.

[0190] Pressure-transition particles may have three or more glass transition temperatures, but it is preferable that the number of glass transition temperatures be two. Forms in which the number of glass transition temperatures is two include: a form in which the resin contained in the pressure-transition particles consists only of a specific styrene-based resin and a specific (meth)acrylic acid ester-based resin; and a form in which the content of other resins other than the specific styrene-based resin and the specific (meth)acrylic acid ester-based resin is low (for example, a form in which the content of other resins is 5% by mass or less relative to the total pressure-transition particles).

[0191] Pressure-transition-resistant particles have at least two glass transition temperatures, with the difference between the lowest and highest glass transition temperatures being 30°C or more. From the viewpoint of making the particles more susceptible to phase transition under pressure, the difference between the lowest and highest glass transition temperatures is more preferably 40°C or more, even more preferably 50°C or more, and even more preferably 60°C or more. The upper limit of the difference between the lowest and highest glass transition temperatures is, for example, 140°C or less, 130°C or less, and 120°C or less.

[0192] The lowest glass transition temperature exhibited by pressure-transition-resistant particles is preferably 10°C or lower, more preferably 0°C or lower, and even more preferably -10°C or lower, from the viewpoint of the particles being easily subjected to a phase transition by pressure. From the viewpoint of suppressing the fluidization of particles in the unpressurized state, it is preferably -90°C or higher, more preferably -80°C or higher, and even more preferably -70°C or higher.

[0193] The highest glass transition temperature exhibited by pressure-transition-resistant particles is preferably 30°C or higher, more preferably 40°C or higher, and even more preferably 50°C or higher, from the viewpoint of suppressing fluidization of the particles when not pressurized. From the viewpoint of the particles being more susceptible to phase transition under pressure, it is preferably 70°C or lower, more preferably 65°C or lower, and even more preferably 60°C or lower.

[0194] The glass transition temperature of pressure-transition-sensitive particles is determined by compressing the pressure-transition-sensitive particles to create a plate-shaped sample and obtaining a differential scanning calorimetry (DSC) curve from the resulting differential scanning calorimetry curve. More specifically, it is determined according to the "extracorporeal glass transition onset temperature" described in JIS K7121:1987 "Method for Measuring Transition Temperatures of Plastics".

[0195] Pressure-transition particles are particles that undergo a phase transition due to pressure and satisfy the following equation 1. Formula 1...10℃≦T1-T2 In Equation 1, T1 is the temperature at which the viscosity is 10,000 Pa·s at a pressure of 1 MPa, and T2 is the temperature at which the viscosity is 10,000 Pa·s at a pressure of 10 MPa. The methods for determining T1 and T2 will be described later.

[0196] The temperature difference (T1-T2) is preferably 10°C or more, more preferably 15°C or more, and more preferably 20°C or more, from the viewpoint of making the particles more susceptible to phase transition under pressure. From the viewpoint of suppressing the fluidization of pressure-transition-prone particles in the unpressurized state, it is preferably 120°C or less, more preferably 100°C or less, and even more preferably 80°C or less.

[0197] The value of T1 is preferably 140°C or lower, more preferably 130°C or lower, even more preferably 120°C or lower, and even more preferably 115°C or lower. The lower limit of temperature T1 is preferably 80°C or higher, and more preferably 85°C or higher. The value of T2 is preferably 40°C or higher, more preferably 50°C or higher, and even more preferably 60°C or higher. The upper limit of temperature T2 is preferably 85°C or lower.

[0198] As an indicator of how easily pressure-induced phase transitions occur in pressure-dependent particles, the temperature difference (T1-T3) between the temperature T1 at which viscosity is 10,000 Pa·s at a pressure of 1 MPa and the temperature T3 at which viscosity is 10,000 Pa·s at a pressure of 4 MPa is used. Preferably, the temperature difference (T1-T3) is 5°C or more. The temperature difference (T1-T2) is generally 25°C or less. From the viewpoint of the pressure-induced phase transition of the particles, it is preferable that the temperature difference (T1-T2) is 5°C or more, and more preferably 10°C or more. The temperature difference (T1-T3) generally has an upper limit of 25°C or less.

[0199] From the viewpoint of ensuring a temperature difference (T1-T3) of 5°C or more, the pressure-phase-transition particles preferably have a temperature T3 of 90°C or less at which they exhibit a viscosity of 10,000 Pa·s under a pressure of 4 MPa, more preferably 85°C or less, and even more preferably 80°C or less. The lower limit of temperature T3 is preferably 60°C or higher.

[0200] The method for determining temperatures T1, T2, and T3 is as follows: Pressure-transition particles are compressed to create pellet-shaped samples. The pellet-shaped samples are placed in a flow tester (Shimadzu Corporation, CFT-500), the applied pressure is fixed at 1 MPa, and the viscosity as a function of temperature at 1 MPa is measured. From the obtained viscosity graph, it is determined that the viscosity at an applied pressure of 1 MPa is 10 4 Determine the temperature T1 when the temperature reaches Pa·s. Determine the temperature T2 in the same manner as the method for temperature T1, except that the applied pressure is changed from 1 MPa to 10 MPa. Determine the temperature T3 in the same manner as the method for temperature T1, except that the applied pressure is changed from 1 MPa to 4 MPa. Calculate the temperature difference (T1-T2) from temperatures T1 and T2. Calculate the temperature difference (T1-T3) from temperatures T1 and T3.

[0201] [Method for producing pressure-phase transition particles] Pressure-transition particles are obtained by adding an external additive to the mother particles after they have been manufactured.

[0202] The mother particles may be produced by either a dry method (e.g., kneading and grinding method) or a wet method (e.g., agglomeration, suspension polymerization, dissolution and suspension method). There are no particular restrictions on these methods, and known methods can be used. Among these, it is preferable to obtain the mother particles by the agglomeration method.

[0203] The following describes, as an example, a method for producing parent particles using the aggregation and coalescence method. When producing parent particles by an aggregation and coalescence method, for example, The process involves preparing a styrene resin particle dispersion in which styrene resin particles containing a specific styrene resin are dispersed (styrene resin particle dispersion preparation process), A step of polymerizing a specific (meth)acrylic acid ester resin in a styrene resin particle dispersion to form composite resin particles containing the specific styrene resin and the specific (meth)acrylic acid ester resin (composite resin particle formation step), The process involves agglomerating composite resin particles in a composite resin particle dispersion to form aggregated particles (aggregated particle formation process), The process involves heating a dispersion of aggregated particles to fuse and combine the aggregated particles, thereby forming mother particles (fusion and combination process), and then producing mother particles.

[0204] The details of each step are explained below. The following description explains a method for obtaining mother particles without mold release agents. Mold release agents and other additives may be used as needed. If the mother particles contain a coloring agent and / or a release agent, in the aggregated particle formation step, the composite resin particle dispersion is mixed with the coloring agent particle dispersion and / or release agent particle dispersion to aggregate the composite resin particles and the coloring agent and / or release agent, thereby forming aggregated particles. The colorant particle dispersion and the release agent particle dispersion are prepared, for example, by mixing the colorant or release agent with a dispersion medium and then performing a dispersion treatment using a known disperser.

[0205] -Preparation process for styrene resin particle dispersion- In the styrene resin particle dispersion preparation step, a styrene resin particle dispersion containing styrene resin particles with a specific styrene resin is prepared. A styrene-based resin particle dispersion is, for example, a dispersion in which styrene-based resin particles are dispersed in a dispersion medium using a surfactant.

[0206] Examples of the dispersion medium include aqueous media such as water and alcohols. These may be used alone or in combination of two or more.

[0207] Examples of the surfactant include anionic surfactants such as sulfate ester salts, sulfonate salts, phosphate esters, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; nonionic surfactants such as polyethylene glycols, alkylphenol ethylene oxide adducts, and polyhydric alcohols. The nonionic surfactant may be used in combination with an anionic surfactant or a cationic surfactant. Among these, anionic surfactants are preferred. The surfactant may be used alone or in combination of two or more.

[0208] Examples of the method for dispersing styrene resin particles in a dispersion medium include a method in which a specific styrene resin and a dispersion medium are mixed and stirred and dispersed using a rotary shear homogenizer, a ball mill having media, a sand mill, a dynomill, or the like.

[0209] Another method for dispersing styrene resin particles in a dispersion medium is an emulsion polymerization method. Specifically, after mixing the polymerization components of a specific styrene resin with a chain transfer agent or a polymerization initiator, an aqueous medium containing a surfactant is further mixed and stirred to prepare an emulsion, and the styrene resin is polymerized in the emulsion. At this time, it is preferable to use dodecanethiol as the chain transfer agent.

[0210] The volume average particle diameter of the styrene resin particles dispersed in the styrene resin particle dispersion is preferably 100 nm or more and 250 nm or less, more preferably 120 nm or more and 220 nm or less, and still more preferably 150 nm or more and 200 nm or less. The volume average particle diameter of the resin particles contained in the resin particle dispersion is measured with a laser diffraction particle size distribution measuring device (for example, LA-700 manufactured by Horiba, Ltd.), and the particle diameter at which the cumulative percentage becomes 50% in the volume-based particle size distribution starting from the smaller diameter side is defined as the volume average particle diameter (D50v). <​ The content of styrene-based resin particles in the styrene-based resin particle dispersion is preferably 30% to 60% by mass, and more preferably 40% to 50% by mass, based on the total mass of the styrene-based resin particle dispersion.

[0212] -Composite resin particle formation process- In the composite resin particle formation process, a specific (meth)acrylic acid ester resin is polymerized in a styrene-based resin particle dispersion to form composite resin particles containing the specific styrene-based resin and the specific (meth)acrylic acid ester resin. In the composite resin particle formation process, a styrene-based resin particle dispersion is mixed with a polymerization component of a specific (meth)acrylic acid ester resin. The specific (meth)acrylic acid ester resin is polymerized in the styrene-based resin particle dispersion to form composite resin particles containing the specific styrene-based resin and the specific (meth)acrylic acid ester resin.

[0213] The composite resin particles are preferably resin particles containing a specific styrene-based resin and a specific (meth)acrylic acid ester-based resin in a state of microphase separation. These resin particles are manufactured, for example, by the following method.

[0214] A polymerization component of a specific (meth)acrylic acid ester resin (a group of monomers containing at least two (meth)acrylic acid esters) is added to a dispersion of styrene resin particles, and an aqueous medium is added as needed. Then, while slowly stirring the dispersion, the temperature of the dispersion is heated to a temperature above the glass transition temperature of the specific styrene resin (for example, 10°C to 30°C higher than the glass transition temperature of the specific styrene resin). Then, while maintaining the temperature, an aqueous medium containing a polymerization initiator is slowly added dropwise, and stirring is continued for a long period of time, ranging from 1 hour to 15 hours. In this case, it is preferable to use ammonium persulfate as the polymerization initiator.

[0215] Although the detailed mechanism is not entirely clear, it is presumed that when the above method is employed, monomers and polymerization initiators are impregnated into the styrene resin particles, and specific (meth)acrylic acid esters polymerize inside the styrene resin particles. As a result, it is presumed that composite resin particles are obtained in which specific (meth)acrylic acid ester resin is contained inside the styrene resin particles, and the specific styrene resin and specific (meth)acrylic acid ester resin form a state of microphase separation inside the particles.

[0216] The volume-average particle size of the composite resin particles dispersed in the composite resin particle dispersion is preferably 140 nm to 300 nm, more preferably 150 nm to 280 nm, and even more preferably 160 nm to 250 nm.

[0217] The content of composite resin particles in the composite resin particle dispersion is preferably 20% by mass or more and 50% by mass or less, and more preferably 30% by mass or more and 40% by mass or less, relative to the total mass of the composite resin particle dispersion.

[0218] -Agglomerated particle formation process- In the aggregated particle formation process, the composite resin particles in the composite resin particle dispersion are aggregated to form aggregated particles. In the aggregated particle formation process, composite resin particles are aggregated to form aggregated particles with a diameter close to that of the target parent particles.

[0219] Specifically, in the aggregated particle formation process, for example, a flocculant is added to a composite resin particle dispersion, the pH of the composite resin particle dispersion is adjusted to be acidic (for example, pH 2 to 5), a dispersion stabilizer is added as needed, and then the mixture is heated to a temperature close to the glass transition temperature of the specific styrene resin (specifically, for example, between the glass transition temperature of the specific styrene resin -30°C and below the glass transition temperature -10°C) to aggregate the composite resin particles and form aggregated particles.

[0220] In the aggregated particle formation process, the composite resin particle dispersion is stirred in a rotary shear homogenizer, a flocculant is added at room temperature (e.g., 25°C), the pH of the composite resin particle dispersion is adjusted to acidic (e.g., pH 2 to 5), a dispersion stabilizer is added as needed, and then heating may be performed.

[0221] Examples of flocculants include surfactants with opposite polarity to the surfactant contained in the composite resin particle dispersion, inorganic metal salts, and metal complexes with a valency of 2 or higher. When a metal complex is used as a flocculant, the amount of surfactant used is reduced and the electrostatic properties are improved. Along with the flocculant, an additive that forms a complex or similar bond with the metal ions of the flocculant may be used as needed. A chelating agent is preferably used as this additive.

[0222] Examples of inorganic metal salts include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate; and inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. As a chelating agent, a water-soluble chelating agent may be used. Examples of chelating agents include oxycarboxylic acids such as tartaric acid, citric acid, and gluconic acid; and aminocarboxylic acids such as iminodiacid acetic acid (IDA), nitrilotriacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA). The amount of chelating agent added is preferably 0.01 parts by mass or more and 5.0 parts by mass or less per 100 parts by mass of resin particles, and more preferably 0.1 parts by mass or more and less than 3.0 parts by mass.

[0223] -Fusion / unification process- In the fusion and coalescence process, the dispersed aggregated particle solution is heated to fuse and coalesce the aggregated particles, forming mother particles. In the fusion and coalescence process, the agglomerated particle dispersion, in which the agglomerated particles are dispersed, is heated to a temperature above, for example, the glass transition temperature of a specific styrene-based resin (for example, 10°C to 30°C higher than the glass transition temperature of a specific styrene-based resin) to fuse and coalesce the agglomerated particles and form mother particles.

[0224] The mother particles obtained through the above processes usually have a sea-island structure having a sea phase containing a specific styrene-based resin and an island phase containing a specific (meth)acrylate-based resin dispersed in the sea phase. In the composite resin particles, when the specific styrene-based resin and the specific (meth)acrylate-based resin were in a state of microphase separation, it is presumed that in the fusion and coalescence process, the specific styrene-based resins gather together to form the sea phase, and the specific (meth)acrylate-based resins gather together to form the island phase.

[0225] The average diameter of the island phase of the sea-island structure is controlled, for example, by increasing or decreasing the amount of the styrene-based resin particle dispersion liquid or at least two kinds of (meth)acrylates used in the composite resin particle formation process, increasing or decreasing the time maintained at a high temperature in the fusion and coalescence process, and the like.

[0226] The mother particles of the core-shell structure are, for example, After obtaining an aggregated particle dispersion liquid (hereinafter, also referred to as a first aggregated particle dispersion liquid in which first aggregated particles are dispersed) in the above-described aggregated particle formation process, the aggregated particle dispersion liquid and the styrene-based resin particle dispersion liquid are further mixed, and aggregated so that styrene-based resin particles further adhere to the surface of the aggregated particles to form second aggregated particles (second aggregated particle formation process); Heating the second aggregated particle dispersion liquid in which the second aggregated particles are dispersed to fuse and coalesce the second aggregated particles to form mother particles of a core-shell structure (core-shell structure formation process); and are manufactured through. The mother particles of the core-shell structure obtained through the above processes have a shell layer containing a specific styrene-based resin. Instead of the styrene-based resin particle dispersion liquid, a resin particle dispersion liquid in which other types of resin particles are dispersed may be used to form a shell layer containing other types of resin.

[0227] After the completion of the fusion and coalescence process, the mother particles formed in the liquid are subjected to a known washing process, solid-liquid separation process, and drying process to obtain the mother particles in a dried state. From the viewpoint of electrostatic charge, the washing process should be thoroughly performed by displacement washing with ion-exchanged water. From the viewpoint of productivity, the solid-liquid separation process should be performed by suction filtration, pressure filtration, etc. From the viewpoint of productivity, the drying process should be performed by freeze-drying, air-flow drying, fluidized bed drying, vibratory fluidized bed drying, etc.

[0228] Pressure-transition-resistant particles are then produced, for example, by adding an external additive to the obtained dried mother particles and mixing them. Mixing can be done using, for example, a V-blender, Henschel mixer, or Lödige mixer. Furthermore, if necessary, coarse particles may be removed using a vibrating screen separator, wind screen separator, or the like.

[0229] The pressure-transition particles may be used as is by coating, or they may be used as an electrostatic image developer. The electrostatic image developer may be a one-component developer containing only the pressure-transition particles, or a two-component developer containing a mixture of pressure-transition particles and a carrier.

[0230] There are no particular restrictions on the carriers, and known carriers can be used. Examples of carriers include coated carriers in which a resin is coated on the surface of a core material made of magnetic powder; magnetic powder dispersed carriers in which magnetic powder is dispersed in a matrix resin; and resin-impregnated carriers in which resin is impregnated into porous magnetic powder. In the case of magnetic powder dispersed carriers and resin-impregnated carriers, the constituent particles of the carrier may be used as the core material, and the surface of this core material may be coated with resin.

[0231] Examples of magnetic powders include magnetic metals such as iron, nickel, and cobalt; and magnetic oxides such as ferrite and magnetite.

[0232] Examples of coating resins and matrix resins include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic acid ester copolymer, straight silicone resin or modified thereof containing organosiloxane bonds, fluororesin, polyester, polycarbonate, phenolic resin, epoxy resin, etc. The coating resin and matrix resin may also contain conductive particles and other additives. Examples of conductive particles include metals such as gold, silver, and copper, carbon black, titanium dioxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate.

[0233] To coat the surface of the core material with resin, one method is to coat it with a coating layer-forming solution prepared by dissolving the coating resin and various additives (used as needed) in a suitable solvent. The solvent is not particularly limited and should be selected considering the type of resin used and its suitability for coating. Specific resin coating methods include the immersion method, in which the core material is immersed in a coating layer forming solution; the spray method, in which the coating layer forming solution is sprayed onto the surface of the core material; the fluidized bed method, in which the coating layer forming solution is sprayed onto the core material while it is suspended by fluidized air; and the kneader coater method, in which the carrier core material and the coating layer forming solution are mixed in a kneader coater, and then the solvent is removed.

[0234] In a two-component developer, the mixing ratio (mass ratio) of pressure-phase-transition particles and carriers is preferably particles:carrier = 1:100 to 30:100, and more preferably 3:100 to 20:100. [Examples]

[0235] The embodiments of the invention will be described in detail below with reference to examples, but the embodiments of the invention are not limited to these examples. In the following description, unless otherwise specified, "parts" and "%" are based on mass.

[0236] Example A <Fabrication of pressure-induced phase-transition particles> [Preparation of styrene-based resin particle dispersion (A1) and composite resin particle dispersion (A1)] • Styrene: 450 copies n-butyl acrylate: 140 parts • Acrylic acid: 20 parts Dodecanethiol: 10 parts A monomer solution was prepared by mixing and dissolving the aforementioned components. Ten parts of anionic surfactant (Dow Chemical Company, DOWFAX2A1) were dissolved in 250 parts of deionized water, and the monomer solution was added and dispersed in a flask to emulsify and obtain an emulsion. One part of an anionic surfactant (DOWFAX2A1, manufactured by Dow Chemical) was dissolved in 555 parts of deionized water. This mixture was then placed in a polymerization flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube. The polymerization flask was heated in a water bath to 75°C while slowly stirring and injecting nitrogen, and the temperature was maintained there. Dissolve 9 parts ammonium persulfate in 43 parts deionized water and pour into a polymerization flask using a quantitative pump. After being dispensed dropwise through a pump over 20 minutes, the emulsified solution was dispensed dropwise through a metering pump over 200 minutes. Afterward, the polymerization flask was kept at 75°C for 3 hours while continuing to stir, and then returned to room temperature (25°C) to complete the first stage of polymerization. This resulted in a styrene-based resin particle dispersion (A1) containing styrene-based resin particles, with a volume-average particle size (D50v) of 195 nm, a glass transition temperature of 53°C, and a weight-average molecular weight of 32,000 determined by GPC (UV detection).

[0237] Next, 240 parts of 2-ethylhexyl acrylate, 160 parts of n-butyl acrylate, and 1200 parts of deionized water were added to a polymerization flask containing a styrene-based resin particle dispersion (A1) whose temperature had cooled to room temperature (25°C), and the mixture was slowly stirred for 2 hours. Subsequently, the temperature was raised to 70°C while stirring continued, and 4.5 parts of ammonium persulfate and 100 parts of deionized water were added dropwise over 20 minutes using a metering pump. After that, the mixture was held for 3 hours while stirring continued to complete the polymerization. After the above steps, a composite resin particle dispersion (A1) was obtained with a volume-average particle size (D50v) of 240 nm, a weight-average molecular weight of 133,000 determined by GPC (UV detection), a number-average molecular weight of 18,000, and a solid content of 30% by mass after adjustment with deionized water.

[0238] The composite resin particles from the obtained composite resin particle dispersion (A1) were dried, and a sample was prepared by embedding the dried composite resin particles in epoxy resin. The sample was then cut with a diamond knife to prepare cross-sectional sections of the composite resin particles. The cut surfaces of the samples were stained with ruthenium tetroxide vapor and then examined by transmission electron microscopy. The cross-sectional observation of the composite resin particles confirmed that the composite resin particles consist of multiple domains of low-Tg (meth)acrylic acid ester resin dispersed in a high-Tg styrene resin that serves as the matrix material. Furthermore, when the glass transition temperature (Tg) behavior of dried composite resin particles was analyzed from -150°C using a differential scanning calorimeter (DSC) manufactured by Shimadzu Corporation, a glass transition due to low Tg (meth)acrylic acid ester resin was observed at -60°C. In addition, a glass transition due to high Tg styrene resin was observed at 53°C (glass transition temperature difference: 113°C).

[0239] [Preparation of Styrene Resin Particle Dispersion (B1)] • Styrene: 450 copies n-butyl acrylate: 135 parts • Acrylic acid: 12 parts Dodecanethiol: Part 9 A monomer solution was prepared by mixing and dissolving the aforementioned components. On the other hand, 10 parts of an anionic surfactant (Dow Chemical Company, DOWFAX2A1) were dissolved in 250 parts of deionized water, the monomer solution was added and dispersed in a flask, and an emulsion was obtained. One part of an anionic surfactant (DOWFAX2A1, manufactured by Dow Chemical) was dissolved in 555 parts of deionized water. This mixture was then placed in a polymerization flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube. The polymerization flask was heated in a water bath to 75°C while slowly stirring and injecting nitrogen, and the temperature was maintained there. Dissolve 9 parts ammonium persulfate in 43 parts deionized water and pour into a polymerization flask using a quantitative pump. After being dispensed dropwise over 20 minutes via a pump, the emulsified solution was dispensed dropwise over 200 minutes via a metering pump. Afterward, the polymerization flask was kept at 75°C for 3 hours while continuing to stir, and then returned to room temperature (25°C) to complete the first stage of polymerization. This results in a styrene-based resin particle with a volume-average particle size (D50v) of 190 nm, a glass transition temperature of 53°C, and a weight-average particle size. A styrene-based resin particle dispersion (B1) with a molecular weight of 33,000, a weight-average molecular weight of 15,000 determined by GPC (UV detection), and a solid content of 40% by mass was obtained by adding deionized water.

[0240] [Preparation of mold release agent dispersion (A1)] Fischer-Tropsch wax: 270 copies (Manufactured by Nippon Seiro Co., Ltd., Product name: FNP-0090, Melting temperature = 90℃) • Anionic surfactant: 1.0 part (Manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK) • Ion-exchanged water: 400 copies The above components were mixed and heated to 95°C, dispersed using a homogenizer (IKA, Ultra-Turrax T50), and then subjected to dispersion treatment for 360 minutes in a Manton-Gorin high-pressure homogenizer (Gorin) to prepare a release agent dispersion (A1) (solid content concentration: 20% by mass) in which a release agent with a volume-average particle size of 0.23 μm was dispersed.

[0241] [Preparation of pressure-transition particles (A1) and developer (A1)] ·Composite resin particle dispersion (A1): 600 parts • Release agent dispersion (A1): 8 parts • Colloidal silica aqueous solution: 13 parts (Manufactured by Nissan Chemical Corporation, Snowtex OS) • Ion-exchanged water: 1000 copies • Anionic surfactants: Part 1 (Dowfax 2A1, manufactured by Dow Chemical Co., Ltd.)

[0242] The above components were placed in a 3-liter reaction vessel equipped with a thermometer, pH meter, and stirrer. At a temperature of 25°C, a 1.0% by mass aqueous solution of nitric acid was added to adjust the pH to 3.0. Then, while dispersing at 5,000 rpm using a homogenizer (IKA Japan Co., Ltd., Ultra-Turrax T50), four parts of the prepared 10% by mass aqueous solution of polyaluminum chloride were added and dispersed for 6 minutes.

[0243] Subsequently, a mantle heater was installed in the reaction vessel, and the temperature was increased at a rate of 0.2°C / min up to 40°C, and then at a rate of 0.05°C / min above 40°C, while adjusting the stirrer speed to ensure sufficient mixing of the slurry. The particle size was measured every 10 minutes using a Multisizer II (aperture diameter: 50 μm, Coulter). When the volume-average particle size reached 7.5 μm, the temperature was maintained, and 115 parts of styrene resin particle dispersion (B1) were added over 5 minutes. After holding for 30 minutes following the addition, the pH of the slurry was adjusted to 6.0 using a 1.0% by mass sodium hydroxide aqueous solution. Subsequently, the temperature was increased to 96°C at a rate of 1°C / min while adjusting the pH to 6.0 every 5°C, and the temperature was maintained at 96°C. Particle shape and surface properties were observed using an optical microscope and a field emission scanning electron microscope (FE-SEM), and particle coalescence was confirmed at 2.0 hours, so the container was cooled to 30°C over 5 minutes with cooling water.

[0244] After cooling, the slurry was passed through a 30 μm nylon mesh to remove coarse particles, and the slurry that passed through the mesh was filtered under reduced pressure using an aspirator. The solids remaining on the filter paper were crushed as finely as possible by hand and added to 10 times the volume of deionized water at 30°C, and stirred for 30 minutes. Subsequently, the mixture was filtered under reduced pressure using an aspirator, the solids remaining on the filter paper were crushed as finely as possible by hand and added to 10 times the volume of deionized water at 30°C, stirred for 30 minutes, and then filtered under reduced pressure again using an aspirator, and the electrical conductivity of the filtrate was measured. This procedure was repeated until the electrical conductivity of the filtrate was 10 μS / cm or less, and the solids were washed away. The washed solids were finely crushed using a wet-dry granulator (Cormill), and then vacuum-dried in a 25°C oven for 36 hours to obtain mother particles (A1). The obtained mother particles (A1) had a volume-average particle size of 8.1 μm, a weight-average molecular weight of 126,000, and a number-average molecular weight of 17,000.

[0245] Next, 1.5 parts of hydrophobic silica (RY50, manufactured by Nippon Aerosil Co., Ltd.) were added to 100 parts of the obtained mother particles (A1), and the mixture was mixed for 30 seconds at a rotation speed of 13,000 rpm using a sample mill. After that, the mixture was sieved using a vibrating sieve with a mesh size of 45 μm to prepare pressure phase transition particles (A1). The volume-average particle size of the obtained pressure phase transition particles (A1) was 8.4 μm.

[0246] Using pressure-transition-resistant particles (A1) as a sample, the thermal behavior was analyzed using a differential scanning calorimeter (Shimadzu Corporation, DSC-60A) in the temperature range of -150°C to 100°C. Glass transition temperatures were observed at -60°C and 53°C.

[0247] When the temperatures T1 and T2 of the pressure-phase-transition particle (A1) were determined using the measurement method described above, the pressure-phase-transition particle (A1) satisfied equation 1, "10°C ≤ T1 - T2".

[0248] A scanning electron microscope (SEM) observation of a cross-section of a pressure-phase-transition particle (A1) revealed a sea-island structure. The pressure-phase-transition particle (A1) had a core containing island phases and a shell layer without island phases. The sea phase contained a styrene-based resin, and the island phase contained a (meth)acrylic acid ester-based resin. The average diameter of the island phase was determined to be 250 nm using the previously described measurement method.

[0249] For pressure-induced phase-transition particles (A1), the temperature difference (T1-T3), an indicator of the particle's susceptibility to phase transition under pressure, was determined. Specifically, temperatures T1 and T3 were measured using a flow tester (Shimadzu Corporation, CFT-500). The result showed that temperature T3 was 76°C and the temperature difference (T1-T3) was 17°C.

[0250] Eight parts of pressure-phase-transition particles (A1) and 100 parts of the resin-coated carrier described below were placed in a V-type blender and stirred for 20 minutes. Then, the mixture was sieved using a vibrating sieve with a mesh size of 212 μm to obtain the developer (A1).

[0251] A solution for forming a coating layer in which zinc oxide was dispersed was prepared by mixing 14 parts of toluene, 2 parts of styrene-methyl methacrylate copolymer (mass ratio: 80 / 20, weight-average molecular weight: 70000), and 0.6 parts of MZ500 (zinc oxide, titanium industry), and stirring with a stirrer for 10 minutes. Next, the coating layer forming solution and 100 parts of ferrite particles (volume average particle size: 38 μm) were placed in a vacuum-degassing kneader, stirred at 60°C for 30 minutes, and then degassed by reducing the pressure while heating, followed by drying to produce a resin-coated carrier.

[0252] <Preparation of toner and developer for image formation> [Crystalline polyester resin dispersion (A2)] A monomer component consisting of 100 mol% dimethyl sebacate and 100 mol% nonanediol, along with 0.3 parts of dibutyltin oxide per 100 parts of the monomer component as a catalyst, was placed in a heated and dried three-necked flask. The air inside the container was then removed by vacuum to create an inert atmosphere with nitrogen gas, and the mixture was stirred and refluxed at 180°C for 4 hours using mechanical stirring.

[0253] Subsequently, the temperature was gradually increased to 230°C under reduced pressure and stirred for 2 hours. Once a viscous state was reached, the mixture was air-cooled to stop the reaction, and crystalline polyester resin (A2) was synthesized. Molecular weight measurement (polystyrene equivalent) by gel permeation chromatography revealed that the obtained crystalline polyester resin (A2) had a weight-average molecular weight (Mw) of 15300, a number-average molecular weight (Mn) of 3800, and an acid value of 13.5 mgKOH / g. Furthermore, when the melting point (Tm) of the crystalline polyester resin (A2) was measured using a differential scanning calorimeter (DSC), it showed a clear endothermic peak, with the endothermic peak temperature being 77.2°C.

[0254] Next, a resin particle dispersion was prepared using crystalline polyester resin (A2) as follows. • Crystalline polyester resin (A2): 90 parts • Ionic surfactant (Neogen RK, Daiichi Kogyo Seiyaku): 1.8 parts • Ion-exchanged water: 210 parts The above ingredients were mixed and heated to 100°C, dispersed in a homogenizer (IKA Ultra-Turrax T50), and then heated to 110°C in a pressure-discharge type Gorin homogenizer for 1 hour to obtain a crystalline polyester resin dispersion (A2) with a volume-average particle size of 210 nm and a solid content of 30% by mass.

[0255] [Amorphous polyester resin dispersion (A2)] • Bisphenol A propylene oxide adduct: 80 mol% • Bisphenol A ethylene oxide 2 molar adduct: 20 mol% Terephthalic acid: 60 mol% Fumaric acid: 20 mol% Dodecenyl succinic anhydride: 20 mol% The monomer components in the above ratio were charged into a 5-liter flask equipped with a stirrer, nitrogen inlet tube, temperature sensor, and rectification column. The temperature was raised to 190°C over 1 hour, and after confirming that the reaction system was being stirred evenly, 1.2 parts of dibutyltin oxide were added to 100 parts of the monomer components. The temperature was further raised to 240°C over 6 hours while distilling off the generated water, and the dehydration condensation reaction was continued at 240°C for another 2 hours to obtain amorphous polyester resin (A2), which is an amorphous polyester resin with a glass transition temperature of 63°C, an acid value of 10.5 mg KOH / g, a weight-average molecular weight of 17000, and a number-average molecular weight of 4200.

[0256] Next, using the obtained amorphous polyester resin (A2), a resin particle dispersion was prepared as follows. • Amorphous polyester resin (A2): 100 units • Ethyl acetate: 50 parts Ethyl acetate was added to a 5-liter separable flask, and then the above resin components were gradually added. The mixture was stirred with a three-in-one motor and completely dissolved to obtain an oil phase. To this stirred oil phase, a total of 2 parts of 10% by mass aqueous ammonia was gradually added dropwise using a dropper. Then, 230 parts of deionized water were gradually added dropwise at a rate of 10 ml / min to induce phase inversion emulsification. Finally, desolvation was carried out under reduced pressure using an evaporator to obtain an amorphous polyester resin dispersion (A2). The volume-average particle size of the amorphous polyester resin particles in this dispersion was 120 nm, and the solid content concentration was 30% by mass.

[0257] [Coloring agent particle dispersion (A1)] • Carbon black (Cabot, Regal 330): 50 copies • Anionic surfactant (manufactured by NOF Corporation, Newlex®): 2 parts • Ion-exchanged water: 198 parts The above components were mixed and pre-dispersed for 10 minutes using a homogenizer (IKA, Ultra-Turrax). Then, dispersion treatment was performed for 15 minutes at a pressure of 245 MPa using an ultimateizer (opposite impact type wet pulverizer, Sugino Machine) to obtain a colorant particle dispersion (A1) with a volume-average particle size of 354 nm and a solid content of 20.0 mass%.

[0258] [Colorant particle dispersion (A2)] • Blue pigment (copper phthalocyanine, CIPigment blue 15:3, manufactured by Dainichi Seika): 50 units • Ionic surfactants (Neogen RK, Daiichi Kogyo Seiyaku): 5 parts • Ion-exchanged water: 195 parts The above components were mixed and dispersed for 10 minutes using a homogenizer (IKA, Ultra-Turrax). Then, the dispersion was performed for 15 minutes at a pressure of 245 MPa using an ultimateizer (opposite impact type wet pulverizer, Sugino Machine) to obtain a colorant particle dispersion (A2) with a volume-average particle size of 462 nm and a solid content of 20.0 mass%.

[0259] [Coloring agent particle dispersion (A3)] • Magenta pigment (CIPigment Red 122): 80 parts • Anionic surfactant (Neogen SC, manufactured by Daiichi Kogyo Seiyaku): 8 parts • Ion-exchanged water: 200 bottles The above components were mixed and dissolved, dispersed for 10 minutes using a homogenizer (Ultra-Turrax T50, IKA Corporation), and then irradiated with 28 kHz ultrasound for 10 minutes using an ultrasonic disperser to obtain a colorant particle dispersion (A3) with a volume-average particle size of 132 nm and a solid content of 29.0 mass%.

[0260] [Coloring agent particle dispersion (A4)] • Yellow pigment (5GX03, manufactured by Clariant): 80 units • Anionic surfactant (Neogen SC, manufactured by Daiichi Kogyo Seiyaku): 8 parts • Ion-exchanged water: 200 bottles The above components were mixed and dissolved, dispersed for 10 minutes using a homogenizer (Ultra-Turrax T50, IKA Corporation), and then irradiated with 28 kHz ultrasound for 20 minutes using an ultrasonic disperser to obtain a colorant particle dispersion (A4) with a volume-average particle size of 108 nm and a solid content of 29.0 mass%.

[0261] [Release agent particle dispersion (A2)] • Olefin wax (melting point: 88°C): 90 parts • Ionic surfactant (Neogen RK, Daiichi Kogyo Seiyaku): 1.8 parts • Ion-exchanged water: 210 parts The above ingredients were mixed and heated to 100°C, dispersed in a homogenizer (IKA Ultra-Turrax T50), and then heated to 110°C in a pressure-discharge type Gorin homogenizer for 1 hour to obtain a release agent particle dispersion (A2) with a volume-average particle size of 180 nm and a solid content of 30% by mass.

[0262] [Production of black toner particles (A1)] • Amorphous polyester resin dispersion (A2): 166 parts • Crystalline polyester resin dispersion (A2): 50 parts • Coloring agent particle dispersion (A1): 25 parts • Release agent particle dispersion (A2): 40 parts The above components were mixed and dispersed in a round stainless steel flask using a homogenizer (Ultra-Turrax T50). Next, 0.20 parts of aluminum chloride were added, and the dispersion process was continued with the Ultra-Turrax T50. The flask was heated to 48°C in a heating oil bath while stirring. After holding at 48°C for 60 minutes, 60 parts of amorphous polyester resin dispersion (A2) were gradually added. Subsequently, the pH of the system was adjusted to 8.0 with a 0.5 mol / l sodium hydroxide aqueous solution, the stainless steel flask was sealed, and the mixture was heated to 90°C while continuing to stir using a magnetic seal, and held for 3 hours.

[0263] After the reaction was complete, the mixture was cooled, filtered, washed with deionized water, and then solid-liquid separated by Nutsche suction filtration. This mixture was then redispersed in 1 liter of deionized water at 40°C and stirred and washed at 300 rpm for 15 minutes. This process was repeated five more times until the filtrate's pH reached 7.5 and its electrical conductivity reached 7.0 μS / cm. Solid-liquid separation was then performed using No. 5A filter paper via Nutsche suction filtration. Subsequently, vacuum drying was continued for 12 hours to obtain black toner particles (A1). When the particle size of these black toner particles (A1) was measured using a Multisizer II, the volume-average particle size D50 was 6.4 μm and the volume particle size distribution index GSDv was 1.21.

[0264] [Creating black toner (A1)] 100 parts of black toner particles (A1), 0.8 parts of decylsilane-treated hydrophobic titania with an average particle size of 15 nm, and 1.3 parts of hydrophobic silica (NY50, manufactured by Nippon Aerosil Co., Ltd.) with an average particle size of 30 nm were mixed together. The mixture was then mixed for 10 minutes at a peripheral speed of 32 m / s using a Henschel mixer, and coarse particles were removed using a sieve with a 45 μm mesh to obtain black toner (A1).

[0265] [Preparation of developer (C1)] • Ferrite particles (volume-average particle size: 50 μm, volume resistivity: 10⁸ Ωcm): 100 parts • Toluene: 14 parts Perfluorooctyl ethyl acrylate / methyl methacrylate copolymer (copolymerization ratio 40 / 60, Mw: 50,000): 1.6 parts • Carbon black (VXC-72, manufactured by Cabot): 0.12 parts • Cross-linked melamine resin particles (number-average particle size: 0.3 μm): 0.3 parts Of the above components, all components except the ferrite particles were mixed and dispersed in a stirrer for 10 minutes to prepare a film-forming solution. This film-forming solution and the ferrite particles were placed in a vacuum-degassed kneader and stirred at 60°C for 30 minutes. Then, the pressure was reduced and toluene was removed by distillation to form a resin film on the surface of the ferrite particles, thereby producing carrier (A2).

[0266] 94 parts of carrier (A2) and 6 parts of black toner (A1) were mixed, stirred at 40 rpm for 20 minutes using a V-blender, and sieved through a sieve with a mesh size of 177 μm to prepare developer (C1).

[0267] [Preparation of cyan toner particles (A2), cyan toner (A2), and developer (C2)] Cyan toner particles (A2) were obtained in the same manner as the black toner particles (A1), except that 20 parts of colorant particle dispersion (A2) were used instead of colorant particle dispersion (A1) in the preparation of black toner particles (A1). The volume-average particle size D50 of the obtained toner particles was 7.2 μm, and the volume particle size distribution index was 1.19. Cyan toner (A2) was obtained in the same manner as black toner (A1), except that cyan toner particles (A2) were used instead of black toner particles (A1). Developer (C2) was obtained in the same manner as developer (C1), except that cyan toner (A2) was used instead of black toner (A1).

[0268] [Preparation of magenta toner particles (A3), magenta toner (A3), and developer (C3)] Magenta toner particles (A3) were obtained in the same manner as the preparation of black toner particles (A1), except that 25 parts of colorant particle dispersion (A3) were used instead of colorant particle dispersion (A1) in the preparation of black toner particles (A1). The volume-average particle size D50 of the obtained toner particles was 6.8 μm, and the volume particle size distribution index was 1.22. Magenta toner (A3) was obtained in the same manner as black toner (A1), except that magenta toner particles (A3) were used instead of black toner particles (A1). Developer (C3) was obtained in the same manner as developer (C1), except that magenta toner (A3) was used instead of black toner (A1).

[0269] [Preparation of yellow toner particles (A4), yellow toner (A4), and developer (C4)] Yellow toner particles (A4) were obtained in the same manner as the black toner particles (A1), except that 25 parts of colorant particle dispersion (A4) were used instead of colorant particle dispersion (A1) in the preparation of black toner particles (A1). The volume-average particle size D50 of the obtained toner particles was 7.4 μm, and the volume particle size distribution index was 1.19. Yellow toner (A4) was obtained in the same manner as black toner (A1), except that yellow toner particles (A4) were used instead of black toner particles (A1). Developer (C4) was obtained in the same manner as developer (C1), except that yellow toner (A4) was used instead of black toner (A1).

[0270] [Preparation of transparent toner particles (A5), transparent toner (A5), and transparent developer (C5)] Transparent toner particles (A5) were obtained in the same manner as the black toner particles (A1), except that a colorant particle dispersion (A1) was not used in the preparation of black toner particles (A1). The volume-average particle size D50 of the obtained toner particles was 7.4 μm, and the volume particle size distribution index was 1.19. Transparent toner (A5) was obtained in the same manner as black toner (A1), except that transparent toner particles (A5) were used instead of black toner particles (A1). A transparent developer (C5) was obtained in the same manner as the developer (C1), except that a transparent toner (A5) was used instead of a black toner (A1).

[0271] <Production of pressure-sensitive printed materials> [Pressure-sensitive printed material (A1)] Developer (A1) containing pressure-phase-transition particles was supplied to the developer unit of a modified Fuji Xerox Color1000 Press machine, which was filled with black, cyan, magenta, and yellow image-forming developers (C1) to (C4).

[0272] Recording paper (OK Prince high-quality paper, manufactured by Oji Paper Co., Ltd.) was set as the recording medium, and recording paper with one side as the lamination surface was prepared so that printed materials could be produced by overlapping and laminating the sheets in a V-fold as follows.

[0273] The image section was formed by applying each of the YMCK colors at a density of 10% across the entire surface. The pressure phase transition layer was formed as follows: On the recording paper, the pressure phase transition layer was formed in the regions corresponding to the outer edges E11, E12, E21, E22, E31, E32, and region C10 of the unfolded object shown in Figure 1 (denoted as outer edge E11, outer edge E12, outer edge E21, outer edge E22, outer edge E31, outer edge E32, and region C10 in Table 1) with the arrangement pattern shown in Table 1, such that the exposed area ratios of the pressure phase transition layer were EA and IA as shown in Table 1. The arrangement patterns for the pressure-induced phase transition layer were "diagonal stripes with a line width of 300 μm," "a dot pattern with a circular diameter of 100 μm," and "a solid layer." The exposure area ratio of the pressure-induced phase transition layer was adjusted by the spacing of the diagonal stripes or the dots in the dot pattern. The width of the region where the exposed area ratio of the pressure phase transition layer is EA (i.e., the width of the region at the outer edge E where the exposed area ratio of the pressure phase transition layer is smaller than the exposed area ratio IA at the central part I of the bonding surface, denoted as "width D" in the table) is as shown in Table 1.

[0274] Furthermore, the exposure area ratio of the pressure-phase transition layer exposed on the recording paper before crimping corresponds to the exposure area ratio of the pressure-phase transition layer in the unfolded material after the printed material has been unfolded. The outer edges E11 and E21 correspond to the outer edges on the rear end of the laminate when the V-folded laminate is passed through a sealer and pressed. In Table 1, the exposed area ratios of the pressure phase transition layer at outer edges E11, E12, E21, E22, E31, and E32 (i.e., the exposed area ratios of the pressure phase transition layer in the region where the exposed area ratio of the pressure phase transition layer at the outer edge E is smaller than the exposed area ratio IA of the pressure phase transition layer at the central part I of the bonding surface) are denoted as EA11, EA12, E21, E22, E31, and E32, respectively.

[0275] Next, using the surface where the image area and the pressure-transition layer were formed as the bonding surface, the recording paper was folded in a V-fold and bonded using a modified PRESSELE LEADA (manufactured by Toppan Forms Co., Ltd.) to produce a pressure-sealed printed material (A1).

[0276] [Pressure-sensitive printed materials (A2) to (A20), (A22), (B1) to (B6)] Except for the changes shown in Table 1, pressure-sensitive printed materials (A2) to (A20), (A22), and (B1) to (B6) were prepared in the same manner as pressure-sensitive printed material (A1).

[0277] [Pressure-sensitive printed material (A21)] Each YMCK color was applied at a density of 10% to form an unfixed image across the entire surface. Pressure-transition particles were then formed on the entire surface of this image, followed by the formation of a pressure-transition layer across the entire surface. A transparent toner image was then formed using a transparent developer (C5) so that the pressure-transition layer remained as a "diagonal line pattern with a line width of 300 μm". Fixation was then performed. The resulting print was then used as the pressed print (A21).

[0278] <Rating> (Tear at the edge of the printed material) After crimping, a small portion of the corner on the opposite side of the folded edge of the printed material was peeled off, and the material was opened using both hands at a speed of approximately 300 mm / sec. The tearing of the edges of the printed material was then evaluated according to the following criteria. ◎: No tearing occurred at the edges when peeled off. ○: No tearing occurred at the edges when peeled off, but paper fiber lifting occurred. △: When peeled off, very minor tearing may occur at the edges, but the tearing will not spread. ×: Tearing occurs at the edges when peeled off.

[0279] (Peeling at the edges of printed materials) The peeling of the edges of the printed material was evaluated as follows: The degree of peeling of the edges of the printed material other than the fold after crimping is evaluated using the following method. ◎: Even when the heat-pressed printed material is bent while under pressure, the edges will not peel off. ○: When bent while compressed, it lifts slightly. △: The edges are slightly peeled and lifted while the bond is still in a crimped state. ×: When the edges are pressed together, they peel off and lift up, and if bent, the peeling propagates to the inside.

[0280] [Table 1-1]

[0281] [Table 1-2]

[0282] From the above results, it can be seen that in this embodiment, compared to the comparative example, the difference in pressure between the front and back pressure surfaces of each pressure-pressed printed material that is pressure-pressed by Z-fold is smaller, and the variation in pressure on the pressure surfaces is reduced.

[0283] Example B <Preparation of a dispersion containing styrene-based resin particles> [Preparation of Styrene Resin Particle Dispersion (St1)] • Styrene: 390 units n-butyl acrylate: 100 parts • Acrylic acid: 10 parts Dodecanethiol: 7.5 parts The above materials were mixed and dissolved to prepare a monomer solution. Eight parts of anionic surfactant (Dowfax 2A1, manufactured by Dow Chemical) were dissolved in 205 parts of deionized water, and the monomer solution was added to disperse and emulsify it to obtain an emulsion. 2.2 parts of anionic surfactant (Dowfax 2A1, manufactured by Dow Chemical) were dissolved in 462 parts of deionized water. This mixture was then placed in a polymerization flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, and heated to 73°C while stirring, and the temperature was maintained there. Three parts of ammonium persulfate were dissolved in 21 parts of deionized water and added dropwise to the polymerization flask via a metering pump over 15 minutes. The emulsion was then added dropwise via a metering pump over 160 minutes. Next, the polymerization flask was kept at 75°C for 3 hours while continuing to stir slowly, and then returned to room temperature (25°C). This resulted in a styrene-based resin particle dispersion (St1) containing styrene-based resin particles, with a volume-average particle size (D50v) of 174 nm, a weight-average molecular weight determined by GPC (UV detection) of 49 k, a glass transition temperature of 54 °C, and a solid content of 42 mass%.

[0284] The styrene resin particle dispersion (St1) was dried to extract the styrene resin particles, and their thermal behavior in the temperature range of -100°C to 100°C was analyzed using a differential scanning calorimeter (Shimadzu Corporation, DSC-60A). One glass transition temperature was observed. Table 2 shows the glass transition temperature.

[0285] [Preparation of styrene resin particle dispersions (St2) to (St13)] Styrene resin particle dispersions (St2) to (St13) were prepared in the same manner as the preparation of styrene resin particle dispersion (St1), except that the monomer was changed as shown in Table 2.

[0286] In Table 2, monomers are abbreviated using the following symbols. Styrene: St, n-butyl acrylate: BA, 2-ethylhexyl acrylate: 2EHA, ethyl acrylate: EA, 4-hydroxybutyl acrylate: 4HBA, acrylic acid: AA, methacrylic acid: MAA, 2-carboxyethyl acrylate: CEA

[0287] [Table 2]

[0288] <Preparation of a dispersion containing composite resin particles> [Preparation of composite resin particle dispersion (M1)] • Styrene resin particle dispersion (St1): 1190 parts (500 parts solids) • 2-Ethylhexyl Acrylate: 250 parts • n-butyl acrylate: 250 units • Ion-exchanged water: 982 units The above materials were placed in a polymerization flask, stirred at 25°C for 1 hour, and then heated to 70°C. 2.5 parts of ammonium persulfate were dissolved in 75 parts of deionized water and added dropwise to the polymerization flask via a metering pump over a period of 60 minutes. Next, the polymerization flask was kept at 70°C for 3 hours while continuing to stir slowly, and then returned to room temperature (25°C). This resulted in a composite resin particle dispersion (M1) containing composite resin particles, with a volume-average particle size (D50v) of 219 nm, a weight-average molecular weight of 219 kJ determined by GPC (UV detection), and a solid content of 32% by mass.

[0289] The composite resin particle dispersion (M1) was dried to extract the composite resin particles, and their thermal behavior was analyzed using a differential scanning calorimeter (Shimadzu Corporation, DSC-60A) in the temperature range of -150°C to 100°C. Two glass transition temperatures were observed. Table 3 shows the glass transition temperatures.

[0290] [Preparation of composite resin particle dispersions (M2) to (M21)] Composite resin particle dispersions (M2) to (M21) were prepared in the same manner as the preparation of composite resin particle dispersion (M1), except that the styrene-based resin particle dispersion (St1) was changed as shown in Table 3, or the polymerization component of the (meth)acrylic acid ester resin was changed as shown in Table 3.

[0291] [Preparation of composite resin particle dispersions (M22) to (M27)] Composite resin particle dispersions (M22) to (M27) were prepared in the same manner as the preparation of composite resin particle dispersion (M1), except that the amounts of 2-ethylhexyl acrylate and n-butyl acrylate used were adjusted.

[0292] In Table 3, monomers are abbreviated using the following symbols. Styrene: St, n-butyl acrylate: BA, 2-ethylhexyl acrylate: 2EHA, ethyl acrylate: EA, 4-hydroxybutyl acrylate: 4HBA, acrylic acid: AA, methacrylic acid: MAA, 2-carboxyethyl acrylate: CEA, hexyl acrylate: HA, propyl acrylate: PA

[0293] [Table 3]

[0294] <Preparation of pressure-induced phase-transition particles> [Preparation of pressure-transition particles (1) and developer (1)] ·Composite resin particle dispersion (M1): 504 parts • Ion-exchanged water: 710 units • Anionic surfactant (Dow Chemical Company, Dowfax 2A1): 1 part

[0295] The above materials were placed in a reaction vessel equipped with a thermometer and a pH meter. A 1.0% by mass aqueous solution of nitric acid was added at a temperature of 25°C to adjust the pH to 3.0. Then, 23 parts of a 2.0% by mass aqueous solution of aluminum sulfate were added while dispersing in a homogenizer (IKA, Ultra-Turrax T50) at a rotation speed of 5000 rpm. Next, a stirrer and a mantle heater were installed in the reaction vessel, and the temperature was increased at a rate of 0.2°C / min up to 40°C, and then at a rate of 0.05°C / min thereafter. The particle size was measured every 10 minutes using a Multisizer II (aperture diameter 50 μm, Beckman-Coulter). When the volume-average particle size reached 5.0 μm, the temperature was maintained, and 170 parts of a styrene resin particle dispersion (St1) were added over 5 minutes. After the addition was complete, the temperature was maintained at 50°C for 30 minutes, and then a 1.0% by mass aqueous solution of sodium hydroxide was added to adjust the pH of the slurry to 6.0. Next, the temperature was increased to 90°C at a rate of 1°C / min while adjusting the pH to 6.0 every 5°C, and the temperature was maintained at 90°C. Particle shape and surface properties were observed using an optical microscope and a field emission scanning electron microscope (FE-SEM), and particle coalescence was confirmed at 10 hours, so the container was cooled to 30°C with cooling water over 5 minutes.

[0296] After cooling, the slurry was passed through a 15 μm nylon mesh to remove coarse particles, and the slurry that passed through the mesh was filtered under reduced pressure using an aspirator. The solids remaining on the filter paper were crushed as finely as possible by hand and added to 10 times the volume of deionized water (at 30°C), and stirred for 30 minutes. Next, the mixture was filtered under reduced pressure using an aspirator, the solids remaining on the filter paper were crushed as finely as possible by hand and added to 10 times the volume of deionized water (at 30°C), stirred for 30 minutes, and then filtered under reduced pressure again using an aspirator, and the electrical conductivity of the filtrate was measured. This procedure was repeated until the electrical conductivity of the filtrate was 10 μS / cm or less, and the solids were washed away.

[0297] The washed solids were finely crushed using a wet-dry granulator (Cormill) and vacuum-dried in an oven at 25°C for 36 hours to obtain mother particles (1). Mother particles (1) had a volume-average particle size of 8.0 μm.

[0298] 100 parts of mother particle (1) and 1.5 parts of hydrophobic silica (manufactured by Nippon Aerosil Co., Ltd., RY50) were mixed and mixed for 30 seconds at a rotation speed of 13,000 rpm using a sample mill. The mixture was sieved using a vibrating sieve with a mesh size of 45 μm to obtain pressure phase transition particles (1).

[0299] Using pressure-transition-sensitive particles (1) as a sample, the thermal behavior was analyzed using a differential scanning calorimeter (Shimadzu Corporation, DSC-60A) in the temperature range of -150°C to 100°C, and two glass transition temperatures were observed. The glass transition temperatures are shown in Table 4.

[0300] When the temperatures T1 and T2 of the pressure phase transition particle (1) were determined by the measurement method described above, the pressure phase transition particle (1) satisfied equation 1, "10°C ≤ T1 - T2".

[0301] A cross-section of the pressure-phase-transition particle (1) was observed using a scanning electron microscope (SEM), revealing a sea-island structure. The pressure-phase-transition particle (1) consisted of a core containing island phases and a shell layer without island phases. The sea phase contained styrene-based resin, while the island phase contained (meth)acrylic acid ester-based resin. The average diameter of the island phases was determined using the previously described measurement method. Table 4 shows the average diameters of the island phases.

[0302] Ten parts of pressure-phase-transition particles (1) and 100 parts of the resin-coated carrier described below were placed in a V-type blender and stirred for 20 minutes. Then, the mixture was sieved using a vibrating sieve with a mesh size of 212 μm to obtain the developer (1).

[0303] Mn-Mg-Sr ferrite particles (average particle size 40 μm): 100 parts • Toluene: 14 parts • Polymethyl methacrylate: 2 parts • Carbon Black (VXC72: Cabot): 0.12 parts The above materials, excluding the ferrite particles, were mixed with glass beads (1 mm in diameter, in the same amount as toluene), and stirred for 30 minutes at a rotation speed of 1200 rpm using a sand mill manufactured by Kansai Paint Co., Ltd. to obtain a dispersion. This dispersion and the ferrite particles were placed in a vacuum-degassed kneader, and dried under reduced pressure while stirring to obtain a resin-coated carrier.

[0304] [Preparation of pressure-phase-transition particles (2) to (27) and developers (2) to (27)] Pressure phase transition particles (2) to (27) and developers (2) to (27) were prepared in the same manner as the preparation of pressure phase transition particles (1), except that the composite resin particle dispersion and styrene-based resin particle dispersion were changed as shown in Table 4.

[0305] When the temperatures T1 and T2 of pressure-phase-transition particles (2) to (27) were determined by the measurement method described above, all of the pressure-phase-transition particles (2) to (27) satisfied equation 1, "10℃ ≤ T1 - T2".

[0306] [Evaluation of pressure-responsive phase transitions] The temperature difference (T1-T3), an indicator of how easily particles undergo a phase transition under pressure, was determined. Each particle was used as a sample, and temperatures T1 and T3 were measured using a flow tester (Shimadzu Corporation, CFT-500). The temperature difference (T1-T3) was then calculated. Table 4 shows the temperature difference (T1-T3).

[0307] [Evaluation of crimping properties] As a printing apparatus, we prepared an apparatus with the configuration shown in Figure 3. Specifically, we prepared a printing apparatus that includes a five-series tandem and intermediate transfer printing means that performs the formation of an image portion on a recording medium and the application of pressure-transitionable particles in a single operation, and a crimping means that has a folding device and a pressing device. Each of the five developing units in the printing system was loaded with pressure-transition particles (or comparative particles), yellow toner, magenta toner, cyan toner, and black toner, respectively. The yellow, magenta, cyan, and black toners were commercially available products manufactured by Fuji Xerox. Fuji Xerox V424 postcard paper was used as the recording medium. The image portion formed on the postcard paper consisted of a mixture of black text and a full-color photographic image with an area density of 30%, and was formed on one side of the postcard paper. The amount of pressure-phase-transition particles (or comparative particles) applied is 3 g / m² to the image-forming area of ​​the image-forming surface of the postcard paper. 2 That's what I decided. The folding device was designed to fold a postcard in half so that the image-forming surface was on the inside. The pressurizing device was set to a pressure of 90 MPa. Under the above apparatus and conditions, ten postcards were continuously produced, each folded in half with the image-forming surface facing inward, and with the image-forming surfaces fixed together. The 10th postcard was cut along its longest side to create rectangular test pieces with a width of 15 mm, and a 90-degree peel test was performed. The peeling speed for the 90-degree peel test was set to 20 mm / min, and the load (N) was measured at 0.4 mm intervals from 10 mm to 50 mm after the start of measurement. The average of these measurements was calculated, and then the load (N) of three test pieces was averaged. The load (N) required for peeling was classified as follows. The results are shown in Table 4.

[0308] A: 0.8N or higher B: 0.6N or higher, less than 0.8N C: 0.4N or higher, less than 0.6N D: 0.2N or higher, less than 0.4N E: Less than 0.2N

[0309] [Table 4] [Explanation of Symbols]

[0310] 500 Printing means 516 Pressure-induced phase transition particles 516A Pressure phase transition particle region 518 Particle dispensing device 518A Supply Roll 520, 520Y, 520M, 520C, 520K inkjet recording heads 564 Fixing device 564A Heated Roll 564B Pressure Roll 200 Crimping means 220 folding device 230 Pressurizing device 231, 232 Pressure Roll P recording medium Recording media after P1 assignment P2 laminate P3 Printed materials

[0311] 300 Printing means 1T, 1Y, 1M, 1C, 1K photoconductor 2T, 2Y, 2M, 2C, 2K Charging Rolls (Example of Charging Method) 3T, 3Y, 3M, 3C, 3K exposure equipment (an example of electrostatic image forming means) 4T, 4Y, 4M, 4C, 4K developing equipment (an example of a developing method) 5T, 5Y, 5M, 5C, 5K Primary Transfer Rolls (Example of Primary Transfer Method) 6T, 6Y, 6M, 6C, 6K Photoconductor Cleaning Device (Example of Cleaning Method) 8T, 8Y, 8M, 8C, 8K cartridges 10T, 10Y, 10M, 10C, 10K units 20. Intermediate transfer belt (an example of an intermediate transfer material) 21 Intermediate Transfer Body Cleaning Apparatus 22 Drive Roll 23 Support Roll 24 Opposing Roll 26. Secondary transfer roll (an example of a secondary transfer means) 28 Heating device (an example of a particle heating means) P recording medium P4 After granting storage medium P5 laminate P6 Printed matter

Claims

1. The recording medium is folded and pressed together using the surface on which the image portion and the pressure-transition layer are formed as the bonding surface, or the recording medium is stacked and pressed together using the surface on which the image portion and the pressure-transition layer are formed as the bonding surface. When the pressure-bonded surfaces of printed materials are separated and the unfolded material is observed, the exposed area ratio EA of the pressure-phase transition layer in the region at a distance of 0.5 mm inward from the edge of the pressure-bonded surface, at the outer edge E corresponding to at least one of the edges of the edge of the pressure-bonded surface, is smaller than the exposed area ratio IA of the pressure-phase transition layer in the central part I of the pressure-bonded surface. A printed material having a non-pressure phase transition layer in the outer edge portion E, and having a non-pressure phase transition layer on top of at least a portion of the pressure phase transition layer.

2. The printed material according to claim 1, wherein the ratio (EA / IA) of the exposed area ratio EA of the pressure phase transition layer to the exposed area ratio IA of the pressure phase transition layer is 0 or more and 0.95 or less.

3. The printed material according to claim 2, wherein the exposure area ratio EA of the pressure phase transition layer is 5% or more and 95% or less.

4. The printed material according to any one of claims 1 to 3, wherein in the outer edge portion E, the width of the region where the exposed area ratio of the pressure phase transition layer is smaller than the exposed area ratio IA of the pressure phase transition layer in the central portion I of the bonding surface is 1 mm or more and 5 mm or less.

5. The printed material according to any one of claims 1 to 4, wherein linear or strip-shaped pressure phase transition layers are arranged in the outer edge portion E.

6. The printed article according to any one of claims 1 to 5, wherein the pressure-phase transition layer comprises a styrene-based resin containing styrene and other vinyl monomers as polymerization components, and a (meth)acrylic acid ester-based resin containing at least two types of (meth)acrylic acid esters as polymerization components, wherein the mass ratio of (meth)acrylic acid esters to the total polymerization components is 90% by mass or more, and has at least two glass transition temperatures, and the difference between the lowest glass transition temperature and the highest glass transition temperature among the glass transition temperatures exhibited by the pressure-phase transition layer is 30°C or more.

7. The printed article according to claim 6, wherein the mass ratio of styrene to the total polymerization components of the styrene-based resin is 60% by mass or more and 95% by mass or less.

8. The printed article according to claim 6 or claim 7, wherein the mass ratio of the two most abundant of the at least two (meth)acrylic acid esters contained as polymerization components in the (meth)acrylic acid ester resin is 80:20 to 20:

80.

9. A pressure phase transition particle application step is performed to apply pressure phase transition particles to a recording medium on which an image portion is formed, A fixing step of fixing at least the pressure-phase-transition particles onto the recording medium to form a pressure-phase-transition layer, The recording medium is folded and pressed together, with the surface on which the image portion and the pressure-transition layer are formed serving as the pressing surface, or the surface on which the image portion and the pressure-transition layer are formed serving as the pressing surface Then, a crimping step is performed in which the recording medium and another recording medium are stacked and crimped together, It has, A method for manufacturing a printed material according to any one of claims 1 to 8, wherein in the step of imparting pressure-transition particles, a region is selected on the recording medium to be imparted with the pressure-transition particles, the pressure-bonded surfaces of the resulting printed material are separated, and when the surface corresponding to the pressure-bonded surface of the printed material in the unfolded material is observed, the exposure area ratio EA of the pressure-transition layer in the region at a distance of 0.5 mm inward from the edge of the pressure-bonded surface at the outer edge E corresponding to at least one of the edges of the edge of the pressure-bonded surface is smaller than the exposure area ratio IA of the pressure-transition layer in the central part I of the pressure-bonded surface.

10. A pressure phase transition particle application step is performed to apply pressure phase transition particles to a recording medium on which an image portion is formed, A fixing step of fixing at least the pressure-phase-transition particles onto the recording medium to form a pressure-phase-transition layer, A crimping step in which the recording medium is folded and crimped with the surface on which the image portion and the pressure phase transition layer are formed serving as the crimping surface, or the recording medium is stacked and crimped with another recording medium with the surface on which the image portion and the pressure phase transition layer are formed serving as the crimping surface, It has, A method for manufacturing a printed material according to any one of claims 1 to 8, wherein a non-pressure phase transition layer is formed on top of at least a portion of the pressure phase transition layer, the pressure-bonded surfaces of the resulting printed material are separated, and when the surface corresponding to the pressure-bonded surface of the printed material in the unfolded material is observed, the exposure area ratio EA of the pressure phase transition layer in the region at a distance of 0.5 mm inward from the edge of the pressure-bonded surface at the outer edge E corresponding to at least one of the edges of the edge of the pressure-bonded surface is smaller than the exposure area ratio IA of the pressure phase transition layer in the central part I of the pressure-bonded surface.

11. A method for manufacturing a printed material according to claim 9 or 10, wherein in the crimping process, the laminate formed by folding the recording medium, or the laminate formed by stacking the recording medium and another recording medium, is passed through a pressurizing device and crimped, with the end where the outer edge E is located being the rear end.

12. A recording medium is folded and pressed together with the surface on which the image portion and the pressure-transition layer are formed serving as the pressing surface, or a recording medium is stacked and pressed together with another recording medium with the surface on which the image portion and the pressure-transition layer are formed serving as the pressing surface. When the pressure-bonded surfaces of printed materials are separated and the unfolded material is observed, the exposed area ratio EA of the pressure-phase transition layer in the region at a distance of 0.5 mm inward from the edge of the pressure-bonded surface, at the outer edge E corresponding to at least one of the edges of the edge of the pressure-bonded surface, is smaller than the exposed area ratio IA of the pressure-phase transition layer in the central part I of the pressure-bonded surface. A method for manufacturing a printed material having a non-formed region of the pressure phase transition layer in the outer edge portion E, A pressure phase transition particle application step is performed to apply pressure phase transition particles to a recording medium on which an image portion is formed, A fixing step of fixing at least the pressure-phase-transition particles onto the recording medium to form a pressure-phase-transition layer, A crimping step in which the recording medium is folded and crimped with the surface on which the image portion and the pressure phase transition layer are formed serving as the crimping surface, or the recording medium is stacked and crimped with another recording medium with the surface on which the image portion and the pressure phase transition layer are formed serving as the crimping surface, It has, A method for manufacturing a printed material, wherein a non-pressure phase transition layer is formed on top of at least a portion of the pressure phase transition layer, the pressure-bonded surfaces of the resulting printed material are separated, and when the surface corresponding to the pressure-bonded surface of the printed material is observed in the unfolded material, the exposed area ratio EA of the pressure phase transition layer in the region at a distance of 0.5 mm inward from the edge of the pressure-bonded surface at the outer edge E corresponding to at least one of the edges of the edge of the pressure-bonded surface is smaller than the exposed area ratio IA of the pressure phase transition layer in the central part I of the pressure-bonded surface.

Images