Image forming apparatus

Abstract

To provide an image formation device which can sufficiently exercise control over temperatures of both front and rear surfaces while inhibiting increase in the number of components.SOLUTION: An image formation device includes a supply device, a temperature control mechanism, and a re-supply mechanism. The temperature control mechanism further includes a first portion which transports a recording medium supplied from the supply device while controlling a temperature; and a second portion which transports the recording medium supplied from the re-supply mechanism while controlling the temperature. The image formation device further includes a temperature control unit which may control the temperatures of the first portion and the second portion to different temperatures.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an image forming apparatus.

Background Art

[0002] In recent years, in order to form high-definition images with a relatively simple configuration for various recording media such as paper and cloth, an apparatus that ejects ink from nozzles of an inkjet head (hereinafter, also simply referred to as a "head") (hereinafter, simply referred to as an "image forming apparatus" in this specification) has been widely spread.

[0003] In order to ensure the quality of high-definition images, it is necessary to prevent defects and failures in advance, and for this purpose, temperature control is performed on various components in the image forming apparatus.

[0004] Examples of the above components include ink, a tank that stores the ink, a head, a recording medium, etc. However, since it is important to ensure the wet spread and uniformity of the ink ejected from the nozzles of the head onto the recording medium, temperature control of the recording medium is particularly important.

[0005] For example, when the ink ejected from the nozzles of the head lands on the recording medium and an image is recorded, if the temperature of the recording medium deviates from the optimal temperature (hereinafter, also simply referred to as the "target temperature") according to the purpose of use of the image, the wet spread of the ink dots deteriorates, and the quality of the recorded image may decrease.

[0006] In particular, when forming images on both sides (front and back) of the recording medium, not only temperature control at the time of ink landing on one side of the recording medium but also sufficient temperature control of the other side, that is, sufficient temperature control on both the front and back sides is required.

[0007] For example, in Patent Document 1, when forming an image on both sides of a recording medium, a temperature control cylinder for the front surface of the recording medium and a temperature control cylinder for the back surface are provided, and temperature control is performed on both the front and back surfaces.

[0008] However, there was still room for improvement in terms of controlling the increase in the number of parts. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2021-94773 [Overview of the project] [Problems that the invention aims to solve]

[0010] This invention has been made in view of the above-mentioned problems and circumstances, and its objective is to provide an image forming apparatus that can suppress the increase in the number of components and adequately control the temperature on both the front and back surfaces of the recording medium. [Means for solving the problem]

[0011] In order to solve the above problems, the inventors investigated the causes of the above problems and found that the above problems could be solved by using a common mechanism for the temperature adjustment mechanism on the surface and the temperature adjustment mechanism on the back of the recording medium, and by separating the temperature adjustment parts within this common mechanism into parts for temperature adjustment on the surface and parts for temperature adjustment on the back, thus leading to the present invention. In other words, the above-mentioned problems according to the present invention are solved by the following means.

[0012] 1. A transport unit that carries and transports the recording medium, An image forming unit that forms an image on the recording medium transported by the transport unit, A temperature control mechanism that supplies the recording medium to the transport unit while adjusting its temperature, A supply device for supplying the recording medium to the temperature control mechanism, A discharge device for discharging the recording medium that has been transported from the transport unit and on which an image has been formed in the image forming unit, A resupply mechanism that supplies the recording medium, which has been transported from the transport unit and on which an image has been formed in the image forming unit, to the temperature control mechanism, An image forming apparatus comprising means for switching whether to transport the recording medium, which has been transported from the transport unit and on which an image has been formed in the image forming unit, to the discharge device or to the resupply mechanism, The temperature control mechanism includes a first part that transports the recording medium supplied from the supply device, It has a second part for transporting the recording medium supplied from the resupply mechanism, The system further comprises a temperature control unit capable of adjusting the temperature of the first part and the second part to different temperatures. An image forming apparatus characterized by the following features.

[0013] 2. The image forming apparatus according to paragraph 1, characterized in that the temperature control unit includes means for heating at least one of the first portion and the second portion.

[0014] 3. The image forming apparatus according to paragraph 2, characterized in that the heating means is a means of heating by supplying a heat transfer medium having different materials for the first part and the second part.

[0015] 4. The image forming apparatus according to paragraph 2, characterized in that the heating means is a means for heating by supplying a heat transfer medium having different temperatures in the first part and the second part.

[0016] 5. The image forming apparatus according to paragraph 2, characterized in that the heating means is a means for heating by supplying different amounts of a heat transfer medium to the first part and the second part.

[0017] 6. The image forming apparatus according to paragraph 2, characterized in that the heating means is a means for heating by supplying radiant heat.

[0018] 7. The image forming apparatus according to claim 2, wherein the heating means is a means for heating by supplying radiant heat of different intensities to the first part and the second part.

[0019] 8. The image forming apparatus according to claim 2, wherein the heating means is a means for heating by supplying radiant heat to the first part and the second part for different times.

[0020] 9. The image forming apparatus according to claim 1, wherein the temperature adjusting unit includes a means for cooling at least one of the first part and the second part.

[0021] 10. The image forming apparatus according to claim 9, wherein the cooling means is a means for cooling by supplying a refrigerant to at least one of the first part and the second part.

[0022] 11. The image forming apparatus according to claim 9, wherein the cooling means is a means for cooling by supplying refrigerants of different temperatures to the first part and the second part.

[0023] 12. The image forming apparatus according to claim 9, wherein the cooling means is a means for cooling by supplying different amounts of refrigerant to the first part and the second part.

[0024] 13. The image forming apparatus according to claim 1, wherein the re-supply mechanism is a mechanism for directly delivering the recording medium to the second part.

[0025] 14. The image forming apparatus according to claim 1, wherein the temperature adjusting mechanism has a temperature adjusting supply cylinder that carries and rotates the recording medium and supplies it to the conveying unit, and the first part and the second part are parts of the temperature adjusting supply cylinder.

Advantages of the Invention

[0026] The above-described means of the present invention make it possible to provide an image forming apparatus that can prevent the apparatus from becoming bulky, suppress the increase in the number of parts, and reduce heater power consumption.

[0027] Although the mechanism by which the effects of this invention manifest or the mechanism of action are not yet clear, we speculate as follows.

[0028] The image forming apparatus of the present invention includes a temperature control mechanism for supplying a recording medium to a transport section while adjusting its temperature, wherein the temperature control mechanism has a first section for transporting the recording medium and a second section for transporting the recording medium supplied from the resupply mechanism, and further includes a temperature adjustment section capable of adjusting the first section and the second section to different temperatures.

[0029] Furthermore, "temperature control mechanism" refers to a structure or system that includes means for adjusting the temperature.

[0030] As mentioned above, in conventional technology, various measures were taken to prevent the temperature of the recording medium from deviating from the target temperature, especially when recording images on both sides of the recording medium.

[0031] As one of the innovations, when forming images on both sides of the recording medium, separate cylinders were provided for temperature control on the front and back surfaces of the recording medium, thereby controlling the temperature on both sides.

[0032] In this invention, the temperature control mechanism is configured to control the temperature of both the front and back surfaces by having a first part of the mechanism adjust the temperature of the recording medium surface and a second part adjust the temperature of the back surface, thereby enabling a single temperature control mechanism to handle temperature control for both surfaces.

[0033] This eliminates the need for separate bodies for temperature control on the front and back surfaces, thus reducing the number of components and enabling sufficient temperature control on both sides. [Brief explanation of the drawing]

[0034] [Figure 1] A side view showing a schematic configuration of an example of the image forming apparatus of the present invention. [Figure 2] Side view showing a schematic configuration of an example of a temperature control mechanism. [Figure 3] A magnified view showing how the recording medium is supplied from the temperature control mechanism to the transport unit during surface printing. [Figure 4] Enlarged section showing the transport path where the recording medium is supplied from the temperature control mechanism to the transport unit during surface printing. [Figure 5] Perspective view of a printing cylinder, which is an example of a transport unit according to the present invention. [Figure 6] A partially enlarged view showing how a recording medium is supplied from the resupply mechanism according to the present invention to the temperature control mechanism. [Figure 7] A partially enlarged diagram showing the transport path through which a recording medium is supplied from the resupply mechanism according to the present invention to the temperature control mechanism. [Figure 8] Block diagram showing the main functional configuration of the image forming apparatus of the present invention. [Figure 9] Flowchart of the processing overview during the execution of an image formation job [Modes for carrying out the invention]

[0035] The present invention provides an image forming apparatus comprising: a transport unit for transporting a recording medium while supporting it; an image forming unit for forming an image on the recording medium transported by the transport unit; a temperature control mechanism for supplying the recording medium to the transport unit while adjusting its temperature; a supply device for supplying the recording medium to the temperature control mechanism; a discharge device for discharging the recording medium that has been transported from the transport unit and on which an image has been formed in the image forming unit; a resupply mechanism for supplying the recording medium that has been transported from the transport unit and on which an image has been formed in the image forming unit to the temperature control mechanism; and means for switching whether to transport the recording medium that has been transported from the transport unit and on which an image has been formed in the image forming unit to the discharge device or to the resupply mechanism, wherein the temperature control mechanism has a first part for transporting the recording medium supplied from the supply device and a second part for transporting the recording medium supplied from the resupply mechanism, and further comprises a temperature adjustment unit capable of adjusting the first part and the second part to different temperatures. This feature is a technical feature common to or corresponding to each of the embodiments (appearances) described below.

[0036] In an embodiment of the present invention, it is preferable from the viewpoint of raising the temperature of the temperature control supply cylinder that the temperature control unit includes means for heating at least one of the first part and the second part.

[0037] It is preferable that the heating means is a means of supplying a heat transfer medium with different materials to the first part and the second part to heat them, from the viewpoint of being able to make the degree of temperature rise different between the first part and the second part.

[0038] It is preferable that the heating means is a means of supplying a heat transfer medium having different temperatures in the first and second parts to heat the recording medium, from the viewpoint that the first and second parts can be heated to different temperatures.

[0039] It is preferable that the heating means is a means of supplying different amounts of heat transfer medium to the first part and the second part to heat them, from the viewpoint of being able to differentiate the thermal efficiency to the recording medium between the first part and the second part.

[0040] From the viewpoint of efficiently raising the temperature of the temperature control supply cylinder, it is preferable that the heating means is a means of supplying radiant heat.

[0041] It is preferable that the heating means is a means that heats the first part and the second part by supplying radiant heat of different intensities to each part, from the viewpoint of being able to make the degree of temperature rise different between the first part and the second part.

[0042] It is preferable that the heating means is a means that heats the first portion and the second portion by supplying radiant heat for different periods of time, from the viewpoint that the temperature rise time of the recording medium can be different between the first portion and the second portion.

[0043] It is preferable that the temperature control unit includes means for cooling at least one of the first part and the second part, from the viewpoint of creating a temperature difference between the first part and the second part.

[0044] It is more preferable, from the viewpoint of creating a temperature difference between the first and second parts, that the cooling means is a means of supplying a refrigerant to at least one of the first and second parts to cool them.

[0045] From the viewpoint of enabling the recording medium to be cooled at different temperatures in the first and second parts, it is preferable that the cooling means is a means of supplying a refrigerant at different temperatures in the first and second parts.

[0046] It is preferable that the cooling means is a means of supplying different amounts of refrigerant to the first part and the second part for cooling, from the viewpoint of being able to make the cooling efficiency of the recording medium different between the first part and the second part.

[0047] It is preferable, from the viewpoint of suppressing temperature loss and stably adjusting the temperature of the recording medium, that the resupply mechanism is a mechanism that directly transfers the recording medium to the second part.

[0048] From the viewpoint of suppressing the increase in parts, it is preferable that the temperature control mechanism has a temperature-controlled supply cylinder that supports and rotates the recording medium to supply it to the transport section, and that the first part and the second part are parts of the temperature-controlled supply cylinder.

[0049] The present invention, its components, and embodiments and models for carrying out the present invention will be described in detail below. In this application, "~" is used to mean that the numerical values ​​before and after it are included as the lower limit and upper limit.

[0050] [Image forming apparatus] Figure 1 is a side view showing a schematic configuration of an example of the image forming apparatus of the present invention. The image forming apparatus of the present invention is not limited to the configuration shown in Figure 1.

[0051] The image forming apparatus (100) of the present invention is A transport unit that carries and transports a recording medium (P), An image forming unit (322) that forms an image on the recording medium (P) transported by the transport unit, A temperature control mechanism that supplies the recording medium (P) to the transport unit while adjusting its temperature, A supply device (221, 223, 231, 311, 312) that supplies the recording medium (P) to the temperature control mechanism, Discharge devices (411, 412, 413, 414, 415, 416, 420, 431) that discharge the recording medium (P) that has been transported from the transport unit and on which an image has been formed in the image forming unit (322), A resupply mechanism (331, 332, 333) supplies the recording medium (P), which has been transported from the transport unit and has had an image formed on it in the image forming unit (322), to the temperature control mechanism, The image forming apparatus (100) is equipped with means for switching whether to transport the recording medium (P), which has been transported from the transport unit and on which an image has been formed in the image forming unit (322), to the ejection device (411, 412, 413, 414, 415, 416, 420, 431) or to the resupply mechanism (331, 332, 333), The temperature control mechanism includes a first part (313a) that transports the recording medium (P) supplied from the supply device (221, 223, 231, 311, 312), It has a second part (313b) for transporting the recording medium (P) supplied from the resupply mechanism (331, 332, 333), The system further includes a temperature control unit capable of adjusting the temperature of the first part (313a) and the second part (313b) to different temperatures. It is characterized by the following:

[0052] In the following description, the temperature control mechanism, which is the main component of the present invention, will be described first, and the other parts will be described afterward.

[0053] 1.Temperature control mechanism The temperature control mechanism according to the present invention includes, for example, a temperature control supply cylinder (313) described later, and transports the recording medium (P) supplied from the supply device (221, 223, 231, 311, 312) to the transport unit.

[0054] In one specific example, the temperature control mechanism may be a temperature control supply cylinder (313), as shown in Figure 1.

[0055] Furthermore, the above-mentioned temperature control mechanism may have a configuration in which the first part (313a) and the second part (313b) are arranged in a belt shape, as shown in Figure 2.

[0056] As shown in Figure 1, the temperature control mechanism may consist only of a temperature-controlled supply cylinder (313), and is a mechanism that transports a recording medium (P) supplied from a supply device (221, 223, 231, 311, 312) while adjusting its temperature using a first part (313a) of the temperature-controlled supply cylinder (313), and then supplies it to the transport section.

[0057] The "transport unit" mentioned above may be, for example, the printing cylinder (321) in Figure 1, but the transport unit according to the present invention is not limited to the shape of the "cylinder".

[0058] Alternatively, the recording medium (P) supplied from the resupply mechanism (331, 332, 333) described later is received by a second part (313b) of the temperature control mechanism, transported while adjusting the temperature, and supplied to the transport section.

[0059] Figure 3 is a magnified view of a portion of the diagram showing how the recording medium is supplied from the temperature control mechanism to the transport unit during surface printing.

[0060] Figure 4 is a partially enlarged view showing the transport path through which the recording medium is supplied from the temperature control mechanism to the transport unit during surface printing.

[0061] In Figures 3 and 4, the temperature control mechanism is shown only as a temperature control supply cylinder as an example, but the present invention is not limited to this.

[0062] In Figure 3, the leading edge of the recording medium (P) supported by the second supply cylinder (312) is transferred at position A to the first part (313a) of the temperature-controlled supply cylinder (313).

[0063] Subsequently, the temperature control supply cylinder (313) rotates in the direction of F1, and the rear end of the recording medium (P) is then transferred at position A to the first part (313a) of the temperature control supply cylinder (313).

[0064] As a result, the recording medium (P) is supported only on the first part (313a) of the temperature control supply cylinder (313).

[0065] The recording medium (P) supported on the first part (313a) of the temperature-controlled supply cylinder (313) is transported in the direction of F1 while its temperature is adjusted on the first part (313a) of the temperature-controlled supply cylinder (313).

[0066] The leading edge of the recording medium (P) supported by the first part (313a) of the temperature-controlled supply cylinder (313) is transferred to the printing cylinder (321) at position C, and then the rear end of the recording medium (P) is transferred to the printing cylinder (321) at position C.

[0067] The arrows in Figure 4 represent part of the transport path when the recording medium (P) is supplied from the supply device to the temperature-controlled supply cylinder and then from the temperature-controlled supply cylinder to the transport unit.

[0068] Furthermore, during surface printing, the recording medium (P) is not transported in the second part (313b) by the temperature-controlled supply cylinder.

[0069] The first supply cylinder (311) and the second supply cylinder (312) are part of the supply device (221, 223, 231, 311, 312) and are responsible for transporting the recording medium (P) to the temperature-controlled supply cylinder (313).

[0070] At this time, for example, the recording medium (P) is transferred from the second supply cylinder (312) to the first part (313a) of the temperature-controlled supply cylinder at position A, and is transported to position C while its temperature is adjusted. Subsequently, the recording medium (P) is supplied to the printing cylinder (321) at position C.

[0071] Position A is the location where the recording medium is directly transferred from the supply device to the temperature-controlled supply cylinder.

[0072] Furthermore, position C is the point where the recording medium is directly transferred and supplied from the temperature-controlled supply cylinder to the transport unit.

[0073] Furthermore, the above-mentioned supply devices (221, 223, 231, 311, 312) do not necessarily have to include a first supply cylinder (311) and a second supply cylinder (312).

[0074] At this time, the recording medium (P) is directly transferred from the supply device (221, 223, 231) to the first part (313a) of the temperature-controlled supply cylinder (313) at position A.

[0075] In an embodiment of the present invention, the supply device (221, 223, 231, 311, 312) is provided with one or more bodies, thereby increasing the design flexibility of the transport path.

[0076] Furthermore, the various mechanisms and other bodies of the image forming apparatus (100) of the present invention are provided with a plurality of openable and closable claw devices (not shown) that hold the front end of the recording medium (P) in the transport direction when closed, and when the recording medium (P) is transported along the following three transport paths from the time ink is applied to one side of the recording medium (P) by the image forming unit (322) until ink is applied to the other side, it is preferable from the viewpoint of improving the accuracy of alignment when forming an image on both sides of the recording medium (P) that the front end of the recording medium (P) in the transport direction is sequentially transferred from the upstream side to the downstream side of the transport direction as the claw device provided on the upstream side of the transport direction opens and the claw device provided on the downstream side of the transport direction closes.

[0077] Transport route (1) A route for transporting recording media from the transport unit to the resupply mechanism. Transport route (2) Route for supplying recording media from the resupply mechanism to the temperature control mechanism Transport route (3) Route for supplying recording media from the temperature control mechanism to the transport unit

[0078] (1.1) Temperature control supply unit In the present invention, the "temperature-controlled supply cylinder" included in the temperature control mechanism is a cylinder that carries a recording medium (P) along a cylindrical outer curved surface (hereinafter, the "cylindrical outer curved surface" is also simply referred to as the "outer surface"), adjusts its temperature, and transports it, and supplies it to the transport section.

[0079] Furthermore, the term "cylindrical surface" as described above includes elliptical surfaces as well.

[0080] Furthermore, the temperature-controlled supply cylinder (313) has a first section (313a) that transports the recording medium (P) supplied from the supply devices (221, 223, 231, 311, 312) to the temperature-controlled supply cylinder (313) while adjusting its temperature, and a second section (313b) that transports the recording medium (P) supplied from the resupply mechanisms (331, 332, 333) while adjusting its temperature, and further comprises a temperature adjustment unit that can adjust the temperature of the first section (313a) and the second section (313b) to different temperatures.

[0081] The temperature-controlled supply cylinder (313) according to the present invention is provided with a first portion (313a) and a second portion (313b) as temperature-adjusting members, as shown in Figures 3 and 4.

[0082] The first part (313a) is a part of the temperature-controlled supply cylinder (313) in the temperature control mechanism that transports the recording medium (P) while adjusting its temperature and supplies it to the transport section.

[0083] The second part is responsible for transporting the recording medium (P) supplied from the resupply mechanism (331, 332, 333), which will be described later, to the temperature control mechanism while adjusting its temperature.

[0084] The first portion (313a) and the second portion (313b) are provided with multiple holes (313ah, 313bh) for circulating fluids such as cold water or hot water. However, the configuration of the temperature control supply cylinder (313) according to the present invention is not limited thereto.

[0085] (1.1.1) Temperature adjustment section The "temperature control unit" according to the present invention refers to a temperature control member or the like provided in a part of the entire image forming apparatus, including the control unit (40).

[0086] The above-mentioned temperature control section includes, for example, an infrared heater that directly heats the temperature control supply unit with radiant heat, and is structurally located on the surface of the temperature control supply unit.

[0087] Furthermore, means such as placing an external heating device outside the image forming apparatus and transferring heat from the external heating device to the temperature control supply cylinder via a hose or the like using a heat transfer medium are also included in the definition of "temperature control members, etc., provided as part of the entire image forming apparatus."

[0088] This then allows for temperature control of the temperature-controlled supply cylinder (313) and the conveying section, etc.

[0089] Details of the control unit (40) will be described later, and the temperature adjustment section near the temperature control supply unit will be described below.

[0090] (Heating means) When ink is applied to a recording medium (P) to form an image, there is a predetermined temperature that is set for each recording medium (P).

[0091] To ensure this, for example, a recording medium (P) at room temperature supplied from a supply device (221, 223, 231, 311, 312) is heated to near a predetermined temperature in a first part (313a) of the temperature-controlled supply cylinder (313) and supplied to the printing cylinder (321), which is the transport path.

[0092] In this case, especially when cardboard is used as the recording medium (P), heat from the surface of the recording medium (P) in contact with the first part (313a) is transferred to the back side.

[0093] The temperature control supply cylinder (313) determines the heating conditions, taking into account the heat transfer described above.

[0094] Furthermore, since the printing cylinder (321), which is the transport path, needs to be kept warm so that the heat transferred to the back side does not decrease further, the surface of the printing cylinder (321), which is the transport path, is heated around its outer circumference by a heater (hereinafter, such a heater will also be simply referred to as "heater H2").

[0095] In an embodiment of the present invention, it is preferable from the viewpoint of the temperature rise of the temperature control mechanism that the temperature control unit includes means for heating at least one of the first part (313a) and the second part (313b).

[0096] It is preferable that the heating means is a means of supplying a heat transfer medium with different materials to the first part (313a) and the second part (313b) to heat them, from the viewpoint of being able to make the degree of temperature rise different between the first part (313a) and the second part (313b).

[0097] Furthermore, the term "material" of the heat transfer medium as used above encompasses a concept that includes the type of substance (material) of the heat transfer medium (e.g., water, oil, air, etc.), its composition, state (e.g., solid, liquid, gas), etc.

[0098] It is preferable that the heating means is a means of supplying a heat transfer medium having different temperatures in the first portion (313a) and the second portion (313b) to heat the recording medium (P) at different temperatures in the first portion (313a) and the second portion (313b).

[0099] It is preferable that the heating means is a means of supplying different amounts of heat transfer medium to the first portion (313a) and the second portion (313b) to heat them, from the viewpoint of being able to differentiate the thermal efficiency to the recording medium (P) between the first portion (313a) and the second portion (313b).

[0100] (Heat transfer method) Methods of heat transfer to the temperature control supply unit include conduction, which involves direct contact with the unit; convection, which involves transfer via wind or air; and radiation, which involves transfer via infrared rays.

[0101] Conduction-based methods include, for example, providing a Peltier roller or belt with a built-in temperature control device, i.e., a sheet-like element.

[0102] The temperature control device described above is suitable because it can switch between cooling and heating operations by switching the polarity (+ and -) of the voltage applied to the sheet-like element.

[0103] Alternatively, for example, a system may be used in which a fluid such as hot water for temperature control is circulated through holes (313ah, 313bh) provided in the first part (313a) and the second part (313b) of the temperature control supply cylinder (313) shown in Figures 3 and 4, and the temperature of the fluid is transferred to the recording medium (P) through which it passes.

[0104] Convection-based methods include, for example, using a fan to blow hot air.

[0105] Radiation methods include, for example, irradiating with infrared rays using a non-contact heater (such as a halogen lamp).

[0106] Although Figure 1 shows an example in which a non-contact type heater is used as a temperature control element installed near the temperature control supply cylinder (313), the present invention is not limited to this (hereinafter, the "non-contact type heater installed near the temperature control supply cylinder" will simply be referred to as "heater H1").

[0107] The heater H1 operates under the control of the control unit (40) and radiates heat to preheat the temperature-controlled supply cylinder (313), thereby heating the temperature-controlled supply cylinder (313) and, consequently, the recording medium (P) to a predetermined temperature.

[0108] Here, in the rotational direction (F1 direction, clockwise) of the temperature control supply cylinder (313), the portion along the outer circumferential surface from position C to position A (see Figure 1) is not through which the recording medium (P) passes. By installing the heater H1 to heat this portion, the heat generated from the heater H1 can be directly radiated to the temperature control supply cylinder (313).

[0109] From the viewpoint of efficiently raising the temperature of the temperature control supply cylinder (313), it is preferable that the heating means is a means of supplying radiant heat.

[0110] It is preferable that the heating means is a means that heats the first part (313a) and the second part (313b) by supplying radiant heat of different intensities to each of them, from the viewpoint of being able to make the degree of temperature rise different between the first part (313a) and the second part (313b).

[0111] It is preferable that the heating means is a means that heats the first portion (313a) and the second portion (313b) by supplying radiant heat for different periods of time, from the viewpoint that the temperature rise time of the recording medium (P) can be different between the first portion (313a) and the second portion (313b).

[0112] (cooling means) It is preferable that the temperature control unit includes means for cooling at least one of the first portion (313a) and the second portion (313b) of the temperature control supply cylinder (313) from the viewpoint of creating a temperature difference between the first portion and the second portion.

[0113] It is more preferable, from the viewpoint of creating a temperature difference between the first and second parts of the temperature control supply cylinder (313), that the cooling means is a means of supplying a refrigerant to at least one of the first part and the second part to cool it.

[0114] (Cooling method) Methods for cooling the temperature control supply cylinder (313) include directly touching and cooling the temperature control supply cylinder (313), and cooling via wind or air.

[0115] Methods for cooling by directly touching the temperature control supply cylinder (313) include, for example, providing a Peltier roller or belt with a built-in temperature control device, i.e., a sheet-like element.

[0116] The temperature control device described above is suitable because it can switch between cooling and heating operations by switching the polarity (+ and -) of the voltage applied to the sheet-like element.

[0117] Alternatively, the system may be configured to lower the temperature of the recording medium (P) passing through it by circulating a fluid such as chilled water through holes (313ah, 313bh) provided in the first part (313a) and the second part (313b).

[0118] Methods of cooling using wind or air include, for example, using a fan to blow cool air onto the surface.

[0119] It is preferable that the cooling means is a means of supplying a refrigerant at different temperatures to the first part (313a) and the second part (313b) to cool them, from the viewpoint that the recording medium (P) can be cooled at different temperatures in the first part (313a) and the second part (313b).

[0120] It is preferable that the cooling means is a means of supplying different amounts of refrigerant to the first part (313a) and the second part (313b) to cool them, from the viewpoint of being able to make the cooling efficiency of the recording medium (P) different between the first part (313a) and the second part (313b).

[0121] (1.1.2) Perimeter In an embodiment of the present invention, the circumference of the temperature control supply cylinder (313) is at least twice the maximum length of the single-wafer recording medium (P) in the transport direction. This increases the length over which the recording medium (P) is in contact with the temperature control supply cylinder (313), allowing sufficient time for temperature adjustment and enabling stable temperature control.

[0122] Furthermore, "maximum length in the transport direction of a single-wafer recording medium" refers to the maximum length in the transport direction of a single recording medium that has been cut (cut) into individual sheets.

[0123] (1.1.3) Thermal conductivity From the viewpoint of enhancing the heat transfer effect to the recording medium (P) and suppressing heat dissipation from the recording medium (P) to the resupply mechanism (331, 332, 333), it is preferable that the material used in the part of the temperature-controlled supply cylinder (313) that comes into contact with the recording medium (P) has excellent thermal conductivity, and it is preferable that the thermal conductivity of the material used in the part of the cylinder (331, 332) of the resupply mechanism (331, 332, 333) that comes into contact with the recording medium (P) is smaller than the thermal conductivity of the material used in the part of the temperature-controlled supply cylinder (313) that comes into contact with the recording medium (P).

[0124] Examples of the above include cases where the material used in the part of the temperature-controlled supply cylinder (313) that comes into contact with the recording medium (P) is aluminum (thermal conductivity 236 [W / m·K]), and the material used in the part of the cylinder (331, 332) of the resupply mechanism that comes into contact with the recording medium (P) is iron (thermal conductivity 83.5 [W / m·K]). In this case, it is possible to suppress the loss of temperature (thermal energy) of the recording medium (P) to the resupply mechanism (331, 332, 333).

[0125] (1.2) Temperature sensor A temperature sensor is installed near the heater H1, opposite to the portion along the outer circumferential surface of the temperature control supply cylinder (313) from position C to position A in the rotational direction (F1 direction, clockwise direction) of the temperature control supply cylinder (313) (hereinafter, such a temperature sensor will be referred to as "temperature sensor (m1)"; not shown), and the temperature sensor (m1) directly detects the temperature of the temperature control supply cylinder (313) and outputs it to the control unit (40).

[0126] Furthermore, the reason why the above-mentioned temperature sensor (m1) can directly detect the temperature of the temperature control supply cylinder (313) is that the recording medium (P) does not pass through the portion of the outer surface of the temperature control supply cylinder (313) from position C to position A in the direction of rotation (F1 direction, clockwise direction).

[0127] For the temperature sensing element of the above temperature sensor (m1), a contact type such as a thermocouple or thermistor may be used, but a non-contact type such as a thermopile is more preferable.

[0128] The control unit (40) controls the heating or cooling operation of the heater H1 and other temperature control components so that the outer surface of the temperature control supply cylinder (313) reaches a predetermined temperature, based on the temperature detected by the temperature sensor (m1).

[0129] (1.3) Transfer of recording media The temperature-controlled supply cylinder (313) is equipped with an openable and closable claw portion (313c, not shown) that holds the front end of the recording medium (P) in the transport direction when closed, thereby transferring the recording medium (P). A cam mechanism is provided that opens and closes each of the multiple claws constituting the claw portion (313c) to transfer the recording medium (P).

[0130] The transfer locations for the recording medium (P) related to the temperature control supply cylinder (313) are the following three locations (see Figures 1, 3, and 4).

[0131] (Position A) The location where the recording medium is directly transferred from the supply device to the temperature control supply cylinder.

[0132] (Position B) The point at which the recording medium is directly transferred from the resupply mechanism to the temperature control mechanism during transport, specifically from the resupply mechanism's body (for example, the second reversing body described later) to the temperature control mechanism.

[0133] (Position C) This is the point where the recording medium is directly transferred and supplied from the temperature-controlled supply cylinder to the transport section.

[0134] The aforementioned cam mechanism closes the open claws of the temperature-controlled supply cylinder (313) when the recording medium (P) is transferred from the second supply cylinder (312) to the temperature-controlled supply cylinder (313), or when it is transferred from the second reversing cylinder (332) of the resupply mechanism (331, 332, 333) to the temperature-controlled supply cylinder (313), thereby causing the temperature-controlled supply cylinder (313) to receive the recording medium (P) from the second supply cylinder (312) or the second reversing cylinder (332) of the resupply mechanism (331, 332, 333).

[0135] Furthermore, when the recording medium (P) is supplied and transferred from the temperature-controlled supply cylinder (313) to the printing cylinder (321), the closed claw portion (313c) opens to perform the operation of transferring the recording medium (P).

[0136] In this case, for example, if the diameter of the second reversing cylinder (332) is 1, the diameter of the temperature control supply cylinder (313) is 2, and the diameter of the printing cylinder (321) is 3, the second reversing cylinder (332) has one claw portion (332a, not shown), the temperature control supply cylinder (313) has two claw portions (313c) at 180° intervals, and the printing cylinder (321) has three claw portions (321a, not shown) at 120° intervals. When the printing cylinder (321) rotates 120° in the counterclockwise direction (F2 direction) of Figure 1, the second reversing cylinder (332) rotates once in the same direction, and the temperature control supply cylinder (313) rotates 180° in the clockwise direction (F1 direction), and the claw portions of each cylinder open and close at opposing positions so that the recording medium (P) is transferred.

[0137] In this specification, when the resupply mechanism (331, 332, 333) comprises two bodies, the body that supplies and transfers the recording medium (P) to the temperature control mechanism, and does not receive the recording medium (P) from the transport unit, is referred to as the "second reversing body."

[0138] 2. Printing cylinder The "transport unit" according to the present invention may be, for example, the printing cylinder shown in Figures 1, 3 to 7.

[0139] In this specification, "printing cylinder" means a cylinder that has the function of carrying a recording medium (P) on its outer surface while controlling its temperature and transporting it, and has the function of transporting the recording medium (P) to the discharge device (411, 412, 413, 414, 415, 416, 420, 431) or the resupply mechanism (331, 332, 333) by switching the transport path, and receiving the recording medium (P) supplied from the temperature control mechanism.

[0140] Figure 5 is a perspective view of a printing cylinder, which is an example of a transport unit according to the present invention.

[0141] The printing cylinder (321) is provided with claws (321a) and an air intake (321s) for supporting the recording medium (P) on its outer surface.

[0142] In this embodiment, the diameters of the printing cylinder (321), temperature control supply cylinder (313), first discharge cylinder (411), and first reversing cylinder (331) are in a ratio of 3:2:2:2, and the printing cylinder (321) has three claw portions (321a) arranged at equal intervals on its outer surface.

[0143] Furthermore, if the resupply mechanism (331, 332, 333) has two cylinders, the cylinder that has the function of receiving the recording medium (P) from the printing cylinder (321) is called the "first reversing cylinder".

[0144] Furthermore, the temperature-controlled supply cylinder (313), the first discharge cylinder (411), and the first reversing cylinder (331) each have claw portions (313c, 411a, 331a, not shown) arranged at equal intervals on two locations on their outer circumferential surfaces.

[0145] The claw portion (321a) of the printing cylinder is operated by a cam mechanism (not shown) that moves in conjunction with the rotation of the printing cylinder (321) and opens and closes at positions facing the temperature control supply cylinder (313), the first discharge cylinder (411), and the first reversing cylinder (331), respectively.

[0146] Specifically, for example, the claw portion (321a) closes when one end of the recording medium (P) is handed over from the temperature control supply cylinder (313), thereby holding one end of the recording medium (P).

[0147] Furthermore, the claw portion (321a) opens at the timing when one end of the recording medium (P) is handed over to the first discharge cylinder (411) or the first reversing cylinder (331), thereby handing over one end of the recording medium (P) to the claw portion (411a, not shown) of the first discharge cylinder (411) or the claw portion (331a, not shown) of the first reversing cylinder (331).

[0148] Furthermore, the printing cylinder (321) has three recording medium (P) holding areas formed by dividing its outer surface into three equal parts, and the printing cylinder (321) is capable of holding up to three recording media (P).

[0149] A cylinder rotation motor (not shown) is connected to the printing cylinder (321), and under the control of the control unit (40), the cylinder rotation motor is driven to hold the recording medium (P) on the outer surface of the printing cylinder (321), and the recording medium (P) is transported by rotating it in the transport direction (counterclockwise direction in Figure 1, direction F2) by an angle proportional to the amount of rotation of the cylinder rotation motor around a rotation axis extending perpendicular to the plane of the paper in Figure 1.

[0150] The printing cylinder (321) and the cylinder rotation motor are responsible for transporting the recording medium (P) so that it faces the nozzle surface of the head (322a, 322b, 322c, 322d).

[0151] (2.1) Temperature control member Temperature control members other than the printing cylinder (321) may be installed near the printing cylinder (321), and the same type as the temperature control supply cylinder (313) can be used.

[0152] Although Figure 1 shows an example in which a non-contact type heater is used as a temperature control element installed near the printing cylinder (321), the present invention is not limited to this.

[0153] Furthermore, in Figure 1, the heater installed at a position opposite to the portion along the outer periphery from position E to position C in the rotational direction of the printing cylinder (321) (the direction in which the recording medium is transported, F2 direction) is simply referred to as "heater H2".

[0154] Here, position E is the point where the recording medium is directly transferred from the printing cylinder to the first reversing cylinder of the resupply mechanism.

[0155] In the printing cylinder (321) shown in Figure 1, the portion along the outer circumferential surface from position E to position C in the rotational direction (the direction in which the recording medium is transported, F2 direction) (see Figure 1) is not a portion over which the recording medium (P) passes. Therefore, it is preferable to install a heater H2 in this portion so that it can be directly heated, as this allows for efficient heat to be radiated to the printing cylinder (321) without going through the recording medium (P), and thus the temperature can be adjusted.

[0156] The heater H2 operates under the control of the control unit (40) and radiates heat to preheat the printing cylinder (321), thereby heating the printing cylinder (321) and, consequently, the recording medium (P) to a predetermined temperature prior to the image formation process on the back surface of the recording medium (P).

[0157] Therefore, since the recording medium (P) is not used, the printing cylinder (321) can be heated more efficiently, which is preferable from the viewpoint of suppressing heater power consumption.

[0158] (2.2) Temperature sensor A temperature sensor is installed near the heater H2, opposite to the portion along the outer circumferential surface from position E to position C in the rotational direction of the printing cylinder (321) (the direction in which the recording medium is transported, F2 direction, counterclockwise direction) (hereinafter, such a temperature sensor will be referred to as "temperature sensor (m2)"; not shown), which directly detects the temperature of the printing cylinder (321) and outputs it to the control unit (40).

[0159] Furthermore, the reason why the above-mentioned temperature sensor (m2) can directly detect the temperature of the printing cylinder (321) is that the recording medium (P) does not pass through the portion of the outer surface of the printing cylinder (321) from position E to position C in the direction of rotation (F2 direction, counterclockwise direction).

[0160] The temperature sensing element of the above-mentioned temperature sensor (m2) can be the same as that of the aforementioned temperature sensor (m1).

[0161] The control unit (40) controls the heating or cooling operation of the temperature adjustment member so that the outer surface of the printing cylinder (321) reaches a predetermined temperature based on the temperature detected by the temperature sensor (m2).

[0162] A temperature sensor (hereinafter referred to as "temperature sensor (m3)" and not shown) is installed near the upstream side of the image forming unit and downstream of position C, to detect the temperature of the recording medium (P) and output it to the control unit (40).

[0163] The temperature detection element of the above-mentioned temperature sensor (m3) can be the same as that of the previously mentioned temperature sensor (m1).

[0164] Furthermore, the temperature sensor (m3) can also detect the temperature of the printing cylinder (321) when the recording medium (P) is not passing through.

[0165] (2.3) Intake section As shown in Figure 5, the intake section (321s) includes a plurality of intake holes provided on the outer circumferential surface of the printing cylinder (321) along which the recording medium (P), whose one end is supported by the claw portion (321a), is placed, and a suction force generating section (not shown) that generates a suction force to draw gas into the printing cylinder (321) through the intake holes.

[0166] Examples of components used in the suction force generating section include blowers and fans.

[0167] In other words, the intake section (321s) uses the suction force generated by the intake of air from the intake hole to draw the recording medium (P) towards the outer surface of the printing cylinder (321).

[0168] As a specific example, the printing cylinder (321) has three sections inside its hollow body corresponding to the holding areas of the three recording media (P), and is equipped with an intake circuit (not shown) that allows for the application of suction force to each intake section (321s) of each holding area by individually selecting the appropriate setting.

[0169] This allows the device to operate in a way that prevents suction force from being applied to holding areas that do not hold a recording medium (P), thus preventing a decrease in suction force by the intake section (321s) in holding areas that do not hold a recording medium (P), as would be the case if the interior were not partitioned.

[0170] In Figure 5, a portion of the recording medium (P) is shown peeling up from the outer surface of the printing cylinder (321). This is for the purpose of illustrating the air intake holes, and when the image forming unit (322) records an image, the entire recording medium (P) is supported so as to lie along the outer surface of the printing cylinder (321).

[0171] (2.4) Transfer of recording media The printing cylinder (321) is provided with openable and closable claw portions (321a) that hold the front end of the recording medium (P) in the transport direction when closed (see Figure 5). These claw portions (321a) are provided at the boundary positions of the three holding areas of the recording medium (P), i.e., at 120° intervals around the rotation axis of the printing cylinder (321). Each of these three claw portions (321a) consists of a plurality of claws arranged in a line along the rotation axis direction of the printing cylinder (X direction in Figure 5) on the outer circumferential surface of the printing cylinder (321).

[0172] Furthermore, the recording medium (P) is transferred in this manner, and a cam mechanism is provided that opens and closes multiple claws constituting the claw portion (321a) to transfer the recording medium (P).

[0173] The transfer points for the recording medium (P) related to the printing cylinder (321) are positions C, D, and E (see Figure 1).

[0174] Position E is the point where the recording medium (P) is directly transferred from the printing cylinder (321) to the cylinders of the resupply mechanism (331, 332, 333).

[0175] The aforementioned cam mechanism causes the recording medium (P) to be transferred from the printing cylinder (321) to the first discharge cylinder (411) of the discharge device (411, 412, 413, 414, 415, 416, 420, 431), or to the first reversing cylinder (331) of the resupply mechanism (331, 332, 333), by opening the claws of the closed claw portion (321a) of the printing cylinder (321) and performing the operation of transferring the recording medium (P) to the first discharge cylinder (411) or the first reversing cylinder (331).

[0176] Furthermore, when the recording medium (P) is transferred from the temperature-controlled supply cylinder (313) to the printing cylinder (321), the open claw portion (321a) of the printing cylinder (321) is closed to receive the recording medium (P) from the temperature-controlled supply cylinder (313).

[0177] In this case, for example, if the diameters of the first discharge cylinder (411) and the temperature control supply cylinder (313) are 2, and the diameter of the printing cylinder (321) is 3, then when the printing cylinder (321) rotates 120° in the counterclockwise direction (F2 direction) as shown in Figure 1, the first discharge cylinder (411) and the temperature control supply cylinder (313) are linked to rotate 180° in the clockwise direction (F1 direction).

[0178] 3. Image forming unit In the present invention, the "image forming unit" refers to a portion of the recording medium (P) where ink is applied to one surface to form an image, and includes an inkjet recording unit (a portion comprising the heads, including the spacing between them) which comprises a plurality of heads that eject ink of different colors and a head drive unit (30) that drives these heads.

[0179] In Figure 1, the print heads (322a, 322b, 322c, 322d) eject ink onto the recording medium (P) from nozzle openings located on the ink ejection surface facing the transport surface of the print cylinder (321) at an appropriate timing corresponding to the rotation of the print cylinder (321) holding the recording medium (P), thereby coating the recording medium (P) with ink and forming an image.

[0180] (Inkjet head) In Figure 1, for example, the print heads (322a, 322b, 322c, 322d) are arranged such that their ink ejection surfaces are separated by a predetermined distance from the transport surface of the printing cylinder (321), and a plurality of nozzles for individually ejecting ink onto the recording medium (P) being transported on the printing cylinder (321) are provided perpendicular to the transport direction of the recording medium (P).

[0181] The print head is equipped with an ink tank (not shown) for storing ink and supplying ink to each print head. It may also be equipped with an ink heater or the like (not shown) as a means of heating the ink before ejection. This makes it possible to optimize the temperature of the ink before ejection, allowing the ink to be ejected with the appropriate viscosity, and further enabling stable image recording.

[0182] The ink path from the ink tank to each print head (322a, 322b, 322c, 322d) is equipped with a supply pressure adjustment mechanism, which adjusts the supply pressure to a pressure slightly lower than atmospheric pressure to prevent ink from spilling out of the nozzles of each print head (322a, 322b, 322c, 322d).

[0183] Furthermore, a head drive unit (30) is provided to drive each head (322a, 322b, 322c, 322d). Based on the control of the control unit (40), a drive signal is supplied to each head at an appropriate timing to deform a piezoelectric element according to the image data, thereby causing an amount of ink corresponding to the pixel value of the image data to be ejected from the nozzle of the corresponding head (322a, 322b, 322c, 322d).

[0184] In the example shown in Figure 1, four print heads (322a, 322b, 322c, 322d) corresponding to yellow (Y), magenta (M), cyan (C), and black (K) inks are arranged from the upstream side in the transport direction of the recording medium (P) in the order of yellow (Y), magenta (M), cyan (C), and black (K) at predetermined intervals.

[0185] Although not shown in the diagram, in one specific example, each head (322a, 322b, 322c, 322d) is provided with multiple recording elements, each having a pressure chamber for storing ink, a piezoelectric element provided on the wall of the pressure chamber, and a nozzle.

[0186] When a drive signal is input to deform the piezoelectric element, this recording element deforms the pressure chamber, changing the pressure inside the chamber, and ejects ink from a nozzle that communicates with the pressure chamber.

[0187] (ink) There are no particular restrictions on the ink, but it is preferable that the ink is an active-ray curing type ink, and that the ink curing and drying device (323) is provided downstream of the image forming unit (322) in the transport unit in the transport unit in the transport direction of the recording medium (P), from the viewpoint that the ink can be cured in a short time by irradiation with active rays.

[0188] Since the curing characteristics of the aforementioned active-wire curing ink are often susceptible to temperature changes, optimizing the temperature control of the transport unit when using the ink makes it possible to form images with better and more stable quality.

[0189] Active-ray curing inks may, for example, be those that harden upon irradiation with ultraviolet light.

[0190] Furthermore, the light source is not limited to ultraviolet rays as described above; any energy ray that has the property of curing ink, such as infrared rays, electron beams, and other energy rays, is acceptable, and the light source is also replaced according to the energy ray.

[0191] Furthermore, the above-mentioned active-ray curing ink may optionally contain a gelling agent, polymerization initiator, polymerization inhibitor, colorants such as dyes and pigments, a dispersant for dispersing pigments, a fixing resin for fixing pigments to a substrate, a surfactant, a pH adjuster, a humectant, a UV absorber, and the like.

[0192] The above-mentioned other components may be present in the above composition as one or more of each type.

[0193] Furthermore, it is preferable, from the viewpoint of achieving good and stable image formation, that the ink is a phase-changing ink, and that the phase change occurs before and after the ink is recorded on the recording medium (P).

[0194] When the ink has the characteristic of undergoing a phase change with temperature, optimizing the temperature control of the transport section controls the viscosity of the ink, prevents mixing of ink droplets ejected from each nozzle of the inkjet head (322a, 322b, 322c, 322d), and enables the formation of a better and more stable image.

[0195] When using inks other than those mentioned above for image formation, for example, inks that do not have the property of undergoing a phase change with temperature, inks that do not have the property of hardening when irradiated with energy rays, or inks that do not have either of these properties, temperature control by the temperature-controlled supply cylinder (313), printing cylinder (321), and other temperature control components is meaningful as long as inks that require image formation at an appropriate temperature are used.

[0196] (Hereafter, the "temperature control supply cylinder, printing cylinder, each heater, the first part (313a) and the second part (313b), and other temperature control components" will be collectively referred to simply as "temperature control components, etc.")

[0197] If the ink contains a solid component containing a colorant and a solvent component, the ink curing and drying apparatus (323) may also be a drying apparatus for evaporating the solvent component.

[0198] Examples of drying equipment include non-contact drying devices such as infrared heaters and hot air blowers.

[0199] Either pigments or dyes can be used as the colorants for the ink, but from the viewpoint of forming images with high weather resistance, pigments are preferred as the colorants.

[0200] Furthermore, conventionally known materials can be used without particular restriction, and for example, organic pigments such as insoluble pigments and lake pigments, and inorganic pigments such as titanium dioxide can be preferably used.

[0201] In image forming processes that eject ink, proper temperature control of the ink is often required to optimize ink viscosity and ensure drying and fixing after image formation.

[0202] To optimize the ink temperature before ejection, the ink can be heated at the print head to maintain the appropriate temperature. However, to optimize the temperature of the ink after ejection, i.e., the ink droplets ejected onto the recording medium (P), temperature control of the recording medium (P) upon which the ink lands is crucial. This requires heating the recording medium (P) or the printing cylinder (321) in contact with it to maintain the appropriate temperature.

[0203] When a recording medium (P) that is particularly thin and has a small heat capacity is transported on the printing cylinder (321), it is easier to maintain the appropriate temperature of the recording medium (P) by heating the surface of the printing cylinder (321) and transferring thermal energy, rather than heating the recording medium (P) itself.

[0204] Furthermore, heating the surface of the printing cylinder (321) when the recording medium (P) is not covering the surface of the printing cylinder (321) is more effective in maintaining a more appropriate temperature.

[0205] To achieve this, as mentioned above, it is effective to install heater H2 so that the portion along the outer surface from position E to position C in the rotation direction (F2 direction, counterclockwise direction) of the printing cylinder (321) is heated, in a direction over which the recording medium (P) does not pass.

[0206] (Ink curing and drying equipment) It is preferable that the ink curing and drying device (323) is provided at a position facing the conveyed recording medium (P) on the downstream side of the image forming unit in the conveying unit in the conveying unit, and that the curing and drying of the ink by the ink curing and drying device (323) is performed at a position upstream in the conveying direction from the position where the conveying of the recording medium (P) is switched between conveying it to the discharge device (411, 412, 413, 414, 415, 416, 420, 431) and conveying it to the temperature control mechanism, in order to prevent the ink-coated surface on the recording medium (P) from coming into contact with the first discharge cylinder (411) or the first reversing cylinder (331) of the resupply mechanism (331, 332, 333) and the ink from transferring to them.

[0207] When ultraviolet-curable ink is used, the ink curing and drying apparatus (323) uses, for example, LEDs or high-pressure mercury lamps, and irradiates the recording medium (P) supported in the transport section with active rays such as ultraviolet light from light-emitting parts arranged over a width perpendicular to the paper surface in Figure 1 using the light emitted by the LEDs or lamps, causing a polymerization reaction of the ink by irradiating the ink dispensed onto the recording medium (P) with ultraviolet light of a wavelength corresponding to the properties of, for example, the polymerization initiator contained in the ink, thereby curing and fixing the ink on the recording medium (P).

[0208] The ink curing and drying device (323) described above is provided, for example, near the outer surface of the printing cylinder (321), downstream of the image forming unit (322) and upstream of the discharge devices (411, 412, 413, 414, 415, 416, 420, 431) with respect to the transport direction of the recording medium (P) due to the rotation of the printing cylinder (321).

[0209] When an active-ray curing type ink is used, the ink curing and drying device (323) irradiates the recording medium (P), which is supported on a printing cylinder (321) and from which the ink has been ejected, with an active ray to cure the ink on the recording medium (P).

[0210] Examples of active rays include ultraviolet rays, but any energy ray that has the property of curing ink, depending on the properties of the ink, such as infrared rays, electron beams, and other energy rays, will suffice.

[0211] In addition to LEDs and high-pressure mercury lamps, other light sources include mercury lamps with operating pressures of several hundred Pa to 1 megapa, light sources usable as germicidal lamps, cold cathode tubes, ultraviolet laser light sources, and metal halide lamps. However, it is desirable to use a light source that can emit ultraviolet light at a higher intensity and is energy-efficient.

[0212] When an ink containing a solid component containing a colorant and a solvent component is used, the ink curing and drying apparatus (323) may also be a drying apparatus for evaporating the solvent component.

[0213] Examples of drying equipment include non-contact drying devices such as infrared heaters and hot air blowers.

[0214] 4.Resupply mechanism The resupply mechanism (331, 332, 333) according to the present invention changes the image target surface by inverting the front and back sides of the recording medium (P) on which an image is formed on one side, and then guides it to the temperature control mechanism.

[0215] Under normal circumstances, the recording medium (P) supplied to the temperature control mechanism from the supply devices (221, 223, 231, 311, 312) is at a higher temperature than the recording medium (P) supplied to the temperature control mechanism from the supply devices (221, 223, 231, 311, 312) that has had its temperature adjusted and ink applied to one side, and which is also heated by the ink curing and drying device (323), resulting in a higher temperature for the recording medium (P) supplied to the temperature control mechanism from the supply devices (221, 223, 231, 311, 312) that has had its temperature adjusted and ink applied to one side, and which is also heated by the ink curing and drying device (323), when it is supplied to the temperature control mechanism from the supply devices (221, 223, 231, 311, 312).

[0216] Therefore, in the present invention, the temperature control function for the supply from the resupply mechanism (331, 332, 333) to the second part (313b) of the temperature control mechanism, and for the temperature control function during transport in the second part (313b), needs to be separate from the aforementioned first part (313a).

[0217] Figure 6 is a partially enlarged view showing how a recording medium is supplied from the resupply mechanism according to the present invention to the temperature control mechanism.

[0218] Figure 7 is a partially enlarged view showing the transport path through which the recording medium is supplied from the resupply mechanism according to the present invention to the temperature control mechanism.

[0219] In Figure 6, the leading edge of the recording medium (P) supported by the second reversing cylinder (332) is transferred at position B to a second part (313b) of the temperature control supply cylinder (313).

[0220] Subsequently, the temperature control supply cylinder (313) rotates in the direction of F1, and the rear end of the recording medium (P) is then transferred at position B to a second part (313b) of the temperature control supply cylinder (313).

[0221] As a result, the recording medium (P) is supported only on the second part (313b) of the temperature control supply cylinder (313).

[0222] The recording medium (P) supported by the second part (313b) of the temperature-controlled supply cylinder (313) is transported in the direction of F1 while its temperature is adjusted by the second part (313b) of the temperature-controlled supply cylinder (313).

[0223] The leading edge of the recording medium (P), supported by the second part (313b) of the temperature-controlled supply cylinder (313), is transferred to the printing cylinder (321) at position C, and then the rear end of the recording medium (P) is transferred to the printing cylinder (321) at position C.

[0224] The arrows in Figure 7 represent parts of the transport path in the recording medium resupply mechanism and the supply path to the temperature control mechanism.

[0225] Furthermore, the recording medium does not pass between position E and position C in the rotational direction of the printing cylinder.

[0226] For example, in Figure 7, the resupply mechanism (331, 332, 333) comprises a first reversing cylinder (331), a reversing swing device (333), and a second reversing cylinder (332). The first reversing cylinder (331), which has the function of receiving the recording medium (P) from the printing cylinder (321), has a diameter approximately twice that of the second reversing cylinder (332), which hands over the recording medium (P) to the temperature-controlled supply cylinder (313). The first reversing cylinder (331) rotates using a motor (hereinafter referred to as the "independent drive motor") (not shown), which is an independent drive source described later.

[0227] The above-mentioned resupply mechanism and temperature control mechanism are not limited to the configurations shown in Figures 1 and 7.

[0228] From the viewpoint of inverting recording media (P) of different lengths, it is preferable that the resupply mechanism (331, 332, 333) includes a cylinder that rotates at the same speed as the linear velocity of the recording medium (P) loading surface of the first supply cylinder (311), second supply cylinder (312), temperature-controlled supply cylinder (313), and printing cylinder (321), as well as a cylinder that rotates at a different speed.

[0229] It is preferable from the viewpoint of suppressing temperature loss and stably adjusting the temperature of the recording medium (P) that the resupply mechanism (331, 332, 333) is a mechanism that directly transfers the recording medium (P) to a second part (313b) of the temperature-controlled supply cylinder (313).

[0230] The resupply mechanism (331, 332, 333) includes a reversing swing device (333) that reverses the surface of the recording medium (P) on which the ink is applied to one side, and then supplies and hands it over to the temperature control mechanism, and the resupply mechanism (331, 332, 333) is provided downstream of the first discharge cylinder (411) of the discharge device (411, 412, 413, 414, 415, 416, 420, 431) in the transport direction of the recording medium (P).

[0231] (4.1) First reversible drum The first reversing cylinder (331) according to the present invention is equipped with a claw portion (331a, not shown) that grips one end of a recording medium (P) with the same structure as the claw portion (321a) of the printing cylinder (321), and has a diameter approximately twice that of the second reversing cylinder (332). It rotates using an independent drive motor, which is an independent drive source from the aforementioned printing cylinder (321) and the second reversing cylinder (332) described below.

[0232] (4.2) Reversing swing device The reversing swing device (333) is provided at positions equidistant from the outer surface of the first reversing drum (331) and the outer surface of the second reversing drum (332).

[0233] When forming an image on both sides of a recording medium (P) (hereinafter, "both sides" will also be simply referred to as "both sides"), in order to perform the function of reversing the front and back sides of the recording medium (P), for example, by receiving the recording medium (P) from the printing cylinder (321) at position E in Figure 7, the recording medium (P) is separated from the printing cylinder (321), and then the recording medium (P) is reversed by the reversing swing device (333) provided in the resupply mechanism (331, 332, 333).

[0234] When the rear end of the recording medium (P) on the first reversing cylinder (331) reaches a position where it faces the other end, the reversing swing device (333) grips the rear end and guides it along the outer surface of the second reversing cylinder (332).

[0235] Subsequently, the recording medium (P) is transported to the second reversing cylinder (332).

[0236] At this time, the trailing end of the transport direction of the recording medium (P) in the first image forming operation becomes the leading end in the transport direction of the second image forming operation.

[0237] (4.3) Second reversible drum The second reversing cylinder (332) supplies and transfers the recording medium (P) to the second part (313b) of the temperature control mechanism, for example, at position B in Figure 7.

[0238] If the resupply mechanism (331, 332, 333) includes a second reversing cylinder (332) as shown in Figure 1, the second reversing cylinder (332) is provided with an openable and closable claw portion (332a) that holds the front end of the recording medium (P) in the transport direction when closed, and the second reversing cylinder (332) is provided with a cam mechanism that opens and closes each of the multiple claws constituting the claw portion (332a) to transfer the recording medium (P).

[0239] (4.4) Transfer of recording media In Figure 1, the first reversing cylinder (331) is provided with an openable and closable claw portion (331a) that holds the front end of the recording medium (P) in the transport direction when closed, and the position where the recording medium (P) is transferred from the printing cylinder (321) to the first reversing cylinder (331) is the aforementioned position E.

[0240] Furthermore, the transfer of the recording medium (P) from the second reversing cylinder (332) to the temperature control supply cylinder (313) is performed when the claw portion (332a) of the second reversing cylinder grips the end of the recording medium (P) and rotates to position B, which is a close opposing position to the temperature control supply cylinder (313). At the same time, the claw portion (332a) of the second reversing cylinder opens by a cam mechanism (not shown) to release the end of the recording medium (P), and the claw of the claw portion (313c) of the temperature control supply cylinder (313), which has reached position B, closes by a cam mechanism (not shown).

[0241] As described above, the first reversing cylinder (331), the reversing swing device (333), and the second reversing cylinder (332) constitute a resupply mechanism (331, 332, 333) that swaps the leading and trailing ends of the recording medium (P) in the transport direction and resupplies it to the temperature-controlled supply cylinder (313). However, the resupply mechanism (331, 332, 333) according to the present invention is not limited to this.

[0242] 5. Feeding device The supply device (221, 223, 231, 311, 312) according to the present invention comprises, for example, a supply tray (231) for storing a recording medium (P), and a supply unit (220) for supplying the recording medium (P) from the supply tray (231) to a temperature control mechanism or a body provided by the supply device (221, 223, 231, 311, 312) (see Figure 1).

[0243] (Supply tray) The supply tray (231) is a plate-shaped member provided on which multiple recording media (P) cut to a predetermined size can be placed in a stacked state with their surface facing upwards.

[0244] Furthermore, it is designed to move up and down according to the amount of recording medium (P) placed on it, and in the direction of this vertical movement, the uppermost recording medium (P) is maintained in a position where it is supplied by the supply unit (220) to the body of the temperature control mechanism or supply device (221, 223, 231, 311, 312).

[0245] The top layer of the recording medium (P) is sucked up by a movable arm equipped with a suction unit (not shown) and transported to a supply belt (223) and rollers (221).

[0246] (Supply Department) The supply unit drives a ring-shaped supply belt (223) supported on the inside by multiple (for example, two) rollers (221) to rotate the rollers (221) with the recording medium (P) placed on it, and transports the recording medium (P) along the supply belt (223) to the body of the temperature control mechanism or supply device (221, 223, 231, 311, 312).

[0247] (Recording medium) The recording medium (P) placed on the supply tray (231) is not particularly limited and can include, but is not limited to, various types of ordinary paper from thin to thick, fine paper, coated printing paper such as art paper or coated paper, water-soluble paper, commercially available Japanese paper or postcard paper, plastic film, cloth, leather, etc., and the color of the recording medium (P) is also not particularly limited.

[0248] 6. Discharge device After the recording medium (P) on which an image has been formed in the image forming unit (322) is transported to the discharge device (411, 412, 413, 414, 415, 416, 420, 431) or to the resupply mechanism (331, 332, 333), it is decided by means of switching whether to transport to the discharge device (411, 412, 413, 414, 415, 416, 420, 431) and the recording medium (P) on which the ink has been applied is transported to the discharge device (411, 412, 413, 414, 415, 416, 420, 431).

[0249] For example, as shown in Figure 1, the discharge device includes a first discharge cylinder (411) that receives the recording medium (P) from the printing cylinder (321), a second discharge cylinder (412) that receives the recording medium (P) from the first discharge cylinder (411), a pair of discharge chains (415) that receive the recording medium (P) from the second discharge cylinder (412) and transport it to the discharge section (420), a pair of sprockets (413) on the second discharge cylinder (412) side that drive the discharge chains (415), a pair of sprockets (414) installed in the discharge section (420), and a plurality of guide rollers (416) that guide the discharge chains (415). The discharge device transports the recording medium (P) received from the printing cylinder (321) and discharges it at the discharge section (420) via the discharge chains (415).

[0250] The first discharge cylinder (411) of the discharge device (411, 412, 413, 414, 415, 416, 420, 431) is equipped with two sets of claws (411a, not shown) that grip one end of the recording medium (P) with the same structure as the claws (321a) of the printing cylinder (321).

[0251] A cam mechanism is provided that, when the claw portion (321a) of the printing cylinder (321) and the claw portion (411a) of the first discharge cylinder (411) are in the transfer position D from the printing cylinder (321) to the discharge device (411, 412, 413, 414, 415, 416, 420, 431), opens and closes the multiple claws constituting the claw portion (321a) of the printing cylinder (321) and the claw portion (411a) of the first discharge cylinder (411) to transfer the recording medium (P).

[0252] Furthermore, the control unit (40) can switch the decision of whether to transport the recording medium (P) to the discharge device (411, 412, 413, 414, 415, 416, 420, 431) or to the resupply mechanism (331, 332, 333) using this cam mechanism.

[0253] (Discharge section) Similar to the first discharge cylinder (411), the second discharge cylinder (412) is also provided with two sets of claw portions (412a, not shown), and the discharge chain (415) is also provided with multiple claw portions (415a, not shown) at intervals of half the circumference of the first discharge cylinder (411) and the second discharge cylinder (412).

[0254] Furthermore, the first discharge cylinder (411) and the second discharge cylinder (412), and the second discharge cylinder (412) and the discharge chain (415) are each provided with cam mechanisms that open and close multiple claws constituting their respective claw sections at opposing positions. The recording medium (P) is passed from the first discharge cylinder (411) through the second discharge cylinder (412) to the discharge chain (415), and at the discharge section (420), the claws of the claw section (not shown) of the discharge chain (415) are opened by the cam mechanism, and the recording medium (P) is placed on a plate-shaped discharge tray (431).

[0255] The discharge unit (420) stores the recording medium (P) on the discharge tray (431) until the recording medium (P) is removed by the user after image formation.

[0256] 7. Interlocking movement of each torso For example, as shown in Figure 1, the first feed cylinder (311), the second feed cylinder (312), the temperature-controlled feed cylinder (313), the first discharge cylinder (411), the second discharge cylinder (412), and several sprockets (413, 414) are each connected by gear trains (not shown) and rotate in conjunction with the printing cylinder (321) by a single cylinder rotation motor, and the second reversing cylinder (332) of the refeeding mechanism (331, 332, 333) rotates in conjunction with the printing cylinder (321) by a gear train (not shown).

[0257] However, of the fuselages (331, 332) of the resupply mechanism (331, 332), only the first reversing fuselage (331) is designed to rotate using an independent drive motor separate from the rotational movement described above.

[0258] In other words, when the reversing swing device (333) reaches position F to receive the recording medium (P) from the first reversing cylinder (331) at a timing linked to the rotation of the printing cylinder (321), rotational speed control according to the size of the recording medium (P) is necessary so that the end of the recording medium (P) that is not supported by the claw portion reaches a position close to and facing the reversing swing device (333). Therefore, the drive source of the first reversing cylinder (331) controls the rotational speed of the reversing motor independently of the rotation of the printing cylinder (321).

[0259] 8. Control Unit Based on the detection signals output from each temperature sensor, the control unit (40) adjusts the set temperature of temperature control members and other components, and performs various controls on the supply devices (221, 223, 231, 311, 312), printing cylinder (321), discharge devices (411, 412, 413, 414, 415, 416, 420, 431), and resupply mechanisms (331, 332, 333), etc., according to the desired image formation conditions.

[0260] Figure 8 is a block diagram showing the main functional configuration of the image forming apparatus of the present invention.

[0261] As mentioned above, in this specification, the temperature control supply cylinder, printing cylinder, heaters, and other temperature control components are collectively referred to simply as "temperature control components, etc."

[0262] The above "image formation conditions" can include various conditions such as the amount of ink (also referred to as the "surface ink amount") that constitutes the image (ink image) recorded on the surface of the recording medium (hereinafter, for the sake of convenience, the "recording medium" is simply referred to as "paper"), the size of the paper (also referred to as the "paper size"), the size of the image formed on the surface of the paper (also referred to as the "surface image size"), the type of ink used, the type of paper (material, basis weight, etc.), the temperature and humidity around the apparatus, and the like.

[0263] (8.1) Surface ink amount, etc. In one specific example, the control unit (40) determines the set temperature in the temperature control member or the like according to these values (in other words, the state of the image recorded on the surface of the paper), including the surface ink amount, the paper size, and the surface image size, as the image formation conditions.

[0264] These values, particularly the surface ink amount, are important factors for estimating the energy of the curing heat generated when the ink irradiated with the active ray cures.

[0265] (8.2) Basis weight, etc. In another specific example, the control unit (40) determines the set temperature in the temperature control supply cylinder (313) according to these values, including the basis weight of the paper and the temperature change amount [°C] of the printing cylinder (321) or the paper, as the image formation conditions.

[0266] (When the basis weight is small: When it is thin paper) Considering the heat capacity or heat retention property based on the above paper conveyance mode and the basis weight of the paper, in the case of thin paper with low heat retention (heat capacity), since the influence of the heat propagated from the printing cylinder (321) to the entire paper is large, it is considered better to determine the set temperature in the temperature control supply cylinder (313) according to the temperature change amount of the printing cylinder (321) rather than the temperature change amount of the paper.

[0267] More specifically, the control unit (40) determines the set temperature in the temperature control supply cylinder (313) according to the temperature change [°C] of the printing cylinder (321) when the basis weight of the paper is small, in other words, when it is thin paper with low heat retention.

[0268] In addition, when using thin paper, it is desirable to set the temperature setting value in the temperature control supply cylinder (313) to the temperature used for temperature adjustment (cooling, etc.) of the printing cylinder (321).

[0269] In this example, the temperature change of the printing cylinder (321) is the difference [°C] between the surface temperature of the printing cylinder (321) immediately before the uppermost part of the inkjet recording unit (the head (322a) in this example) and the surface temperature of the printing cylinder (321) near the upstream side of the location of the ink curing and drying device (323).

[0270] Furthermore, the temperature sensor used to detect the surface temperature of the recording medium or printing cylinder immediately before the uppermost part of the inkjet recording section is referred to as the temperature sensor (m3).

[0271] Furthermore, a temperature sensor used to detect the surface temperature of the recording medium or printing cylinder near the upstream side of the ink curing and drying device is referred to as a temperature sensor (m4).

[0272] [Creation of a correspondence table between the image formation conditions for thin paper and the set temperature of the temperature-controlled supply cylinder] In this embodiment, it is preferable to experimentally determine the temperature difference under various image forming conditions (such as surface ink amount or energy amount of active rays output from the ink curing / drying device (323), various thin paper sizes, etc.), and to create a correspondence table between the image forming conditions (including the temperature difference and the set temperature in the temperature control supply cylinder (313)) and the set temperature of the printing cylinder (321).

[0273] (If the basis weight is high: if it is thick cardboard) In the case of thick paper with high heat retention (heat capacity), the effect of heat transmitted from the printing cylinder (321) to the entire sheet of paper is reduced. Therefore, it is desirable to measure the actual temperature change of the paper (thick paper) and set the temperature value in the temperature control supply cylinder (313) to the temperature for temperature adjustment (cooling, etc.) on the back of the paper (thick paper).

[0274] More specifically, the control unit (40) determines the set temperature in the temperature control supply cylinder (313) according to the temperature change [°C] of the paper (cardboard) when the basis weight of the paper is large, in other words, when it is thick cardboard with a large heat capacity and good heat retention.

[0275] Here, the change in paper temperature is the difference [°C] between the paper temperature measured by the temperature sensor (m3) before image formation and the paper temperature measured by the temperature sensor (m4) after image formation (after active ray irradiation).

[0276] Furthermore, even with the cardboard described above, it is preferable to create a correspondence table between the image formation conditions (including the difference temperature and the set temperature in the temperature control supply cylinder (313)) and the set temperature of the printing cylinder (321).

[0277] (8.3) Temperature control member Although not shown in Figures 1 to 7, in order to control the temperature of the paper on which double-sided images are formed, temperature control members other than the printing cylinder (321) and the temperature control supply cylinder (313) can also be used, such as a non-contact heater that emits infrared rays (e.g., a halogen lamp), a blower fan for heating or cooling, rollers and belts with built-in thermoelectric conversion devices, etc.

[0278] Furthermore, the aforementioned printing cylinder (321) and temperature-controlled supply cylinder (313) can have thermoelectric conversion devices built into them, and by installing the above-mentioned temperature control member nearby, the printing cylinder (321) and temperature-controlled supply cylinder (313) themselves, or the paper, can be heated or cooled.

[0279] When a fan is used as a temperature control element, for example, a known Peltier fan can be used, and the control unit (40) can adjust the temperature of the paper by changing the wind speed of the fan or the temperature of the air being blown (wind temperature).

[0280] However, if the fan speed is increased too much, problems such as paper misalignment may occur, so it is desirable for the control unit (40) to primarily control the air temperature (i.e., the set temperature of the temperature control device).

[0281] (8.4) Functions of various elements constituting an image forming apparatus The image forming apparatus (100) of the present invention, as shown in Figure 1 for example, is broadly composed of a supply device (221, 223, 231, 311, 312), a printing cylinder (321), an ejection device (411, 412, 413, 414, 415, 416, 420, 431), and a resupply mechanism (331, 332, 333), and has an image forming unit (322) and a transport path switching process unit (20). The image forming apparatus (100) will be described below in terms of its functional configuration.

[0282] Referring to Figure 8, the image forming apparatus includes a control unit (40) that controls the entire apparatus, a data input unit (10) into which various data related to the image forming job are input and stored, an inkjet recording unit including a head drive unit (30), an ink curing and drying device (323), and a temperature detection unit (80), etc.

[0283] (Data entry section) The data input unit (10) includes an input interface and memory that can be connected to an external device such as a PC (personal computer) (not shown).

[0284] For memory, for example, an HDD (Hard Disk Drive) can be used, and DRAM (Dynamic Random Access Memory) may also be used in combination.

[0285] The data input unit (10) acquires (inputs and stores) data related to an image forming job (such as job commands, image data of the image to be printed, and various setting data) from an external device under the control of the control unit (40), and outputs the image data to the head driving unit (30) when executing the image forming job.

[0286] (Inkjet recording unit) The "inkjet recording unit" is provided in the image forming unit, and is a location where ink is applied to one side of the paper to form an image, and includes a plurality of heads (322a, 322b, 322c, 322d) that eject inks of different colors, and a head driving unit (30) that drives these heads.

[0287] In FIG. 1, the heads (322a, 322b, 322c, 322d) eject ink onto the paper from nozzle openings provided on the ink ejection surface facing the conveyance surface of the printing cylinder (321) at an appropriate timing according to the rotation of the printing cylinder (321) holding the paper, apply the ink to the paper, and form an image.

[0288] [Head driving unit] The head driving unit (30) supplies a driving signal that causes the piezoelectric element to deform according to the image data at an appropriate timing to each head (322a, 322b, 322c, 322d) based on the control of the control unit (40), thereby ejecting an amount of ink corresponding to the pixel value of the image data from the nozzles of the corresponding heads (322a, 322b, 322c, 322d).

[0289] (Ink curing / drying device) The ink curing / drying device (323) has a light emitting unit arranged over the width of the printing cylinder (321) in the direction perpendicular to the paper surface of FIG. 1.

[0290] The ink curing / drying device (323) irradiates the paper carried on the printing cylinder (321) with energy rays corresponding to the properties of the ink from the light emitting unit, and cures or dries the ink ejected onto the paper to fix it.

[0291] The example shown in Figure 1 assumes that ultraviolet (UV) curable ink is ejected from the print heads (322a, 322b, 322c, 322d).

[0292] The ink used in the inkjet recording unit is not limited to this, and may also be an ink that hardens or dries upon irradiation with other energy rays such as infrared rays or electron beams.

[0293] Downstream of the ink curing and drying device (323) in the transport direction, a first discharge cylinder (411) is provided that faces the printing cylinder (321).

[0294] Furthermore, a first reversing drum (331) and a temperature-controlled supply drum (313) are provided downstream of the first discharge drum (411).

[0295] Of the above, the first discharge cylinder (411) is responsible for transferring the paper to the discharge devices (411, 412, 413, 414, 415, 416, 420, 431) when the image forming job is completed, and the first reversing cylinder (331) transfers the paper to the resupply mechanisms (331, 332, 333) when forming the back image after the front image has been formed.

[0296] After the paper is inverted in the above-mentioned resupply mechanism (331, 332, 333), it is supplied to the temperature control mechanism, which is responsible for transferring the paper received from the resupply mechanism (331, 332, 333) to the printing cylinder (321) while adjusting the temperature using the second part (313b).

[0297] Furthermore, the first discharge cylinder (411) and the first reversing cylinder (331) are each equipped with a claw portion (411a) and a claw portion (331a) that can be switched open or closed by control of the control unit (40).

[0298] The aforementioned claws, such as the first discharge cylinder (411) and the first reversing cylinder (331), form part of the transport path switching process section (20) (see Figure 8) for switching the destination of the paper transport.

[0299] (Temperature detection unit) Each temperature sensor provided in the image forming apparatus (100) of the present invention detects the temperature of the paper, the printing cylinder (321), and the temperature control supply cylinder (313) respectively (hereinafter, each part detected by the above temperature sensor will also be simply referred to as the "temperature detection unit"), and outputs the detection result (detection signal) to the control unit (40).

[0300] The temperature sensor (m1) is installed near the heater H1 and opposite to the portion along the outer surface from position C to position A in the rotational direction (F1 direction, clockwise direction) of the temperature control supply cylinder (313), and detects the temperature of the printing cylinder (321).

[0301] The temperature sensor (m2) is installed near the heater H2 and opposite to the portion along the outer surface from position E to position C in the rotational direction of the printing cylinder (321) (paper transport direction, F2 direction, counterclockwise direction), and detects the temperature of the printing cylinder (321).

[0302] The temperature sensor (m3) detects the surface temperature of the paper or printing cylinder immediately before the upstream end of the inkjet recording unit and outputs it to the control unit (40).

[0303] The temperature sensor (m4) detects the surface temperature of the paper or printing cylinder near the upstream side of the ink curing and drying device.

[0304] In addition, another temperature sensor, which detects the temperature of the paper before it is supplied to the feeding unit, is referred to as temperature sensor (m5).

[0305] While contact-type elements such as thermocouples and thermistors may be used as temperature detection elements for each temperature sensor provided in the image forming apparatus of the present invention, non-contact-type elements such as thermopiles are more preferred.

[0306] The control unit (40) then performs various temperature control processes based on the detection signals output from each of the temperature sensors arranged as described above.

[0307] (others) The control unit (40) includes a CPU (Central Processing Unit), RAM (Random Access Memory), and ROM (Read Only Uses Memory.

[0308] (CPU) Of the above, the CPU reads various control programs and setting data stored in ROM, stores them in RAM, and executes those programs to perform various calculations. Furthermore, the CPU provides overall control over the operation of the inkjet recording system.

[0309] (RAM) RAM provides the CPU with working memory space and stores temporary data. Furthermore, RAM may include non-volatile memory.

[0310] (ROM) ROM stores various control programs and configuration data executed by the CPU. Note that instead of ROM, EEPROM (Electrically Erasable Rewritable non-volatile memory such as programmable read-only memory or flash memory may be used.

[0311] (8.5) Procedure for controlling the image formation job In the image forming apparatus of the present invention, the following image forming jobs are controlled under the functional configuration of the control unit (40) described above.

[0312] Figure 9 is a flowchart illustrating the overview of the processing during the execution of an image formation job. The overview of the processing during the execution of an image formation job will be explained below with reference to this flowchart.

[0313] <Start> When an image forming job is executed, the control unit (40) drives and controls the cylinder rotation motor to start the rotation of the printing cylinder (321).

[0314] <Step S1> The control unit (40) refers to a correspondence table between the image formation conditions for thin or thick paper and the set temperature of the temperature-controlled supply cylinder (313), which has been prepared in advance as described above, to determine the target temperatures of the first part (313a), the second part (313b) of the temperature-controlled supply cylinder (313) and the printing cylinder (321) corresponding to the current image formation conditions, and changes the set temperature of the temperature control members, etc.

[0315] <Step S2> Next, the control unit (40) operates temperature control components at a predetermined timing to adjust the surface temperature of the first part (313a), the second part (313b) of the temperature control supply cylinder (313) and predetermined areas of the printing cylinder (321), and then proceeds to step S3.

[0316] Here, the "predetermined area" refers to the area from when the paper (thin or thick paper) is transported to the temperature-controlled supply cylinder (313) before and after the front-to-back inversion operation until it is transported to the printing cylinder (321).

[0317] <Step S3> The control unit (40) starts monitoring the output (detection signal) of each temperature sensor used for temperature detection of the printing cylinder (321) and the temperature control supply cylinder (313), and stores the detected temperature.

[0318] <Step S4> Next, the control unit (40) estimates the temperature at the image formation position of the paper before inversion, based on the value stored in step S3 and the various image formation conditions described above (such as surface ink amount).

[0319] In one specific example, in step S4, the control unit (40) estimates the paper temperature at the image formation position on the paper, that is, the paper temperature at the position on the temperature-controlled supply cylinder (313) facing the inkjet recording section, based on the temperature of the temperature-controlled supply cylinder (313) detected by the temperature sensor (m1), the temperature of the printing cylinder (321) detected by the temperature sensor (m2), and the paper thickness and specific heat.

[0320] <Step S5> Next, the control unit (40) determines whether the estimated paper temperature before flipping the paper over falls within the range of the target temperature (e.g., 40-50°C).

[0321] Here, the control unit (40) changes the set temperatures of the temperature control supply cylinder, printing cylinder, each heater, the first part (313a) and the second part (313b), and other temperature control members, etc. (as mentioned above, but hereinafter simply referred to as "temperature control members, etc.") based on the difference between the estimated paper temperature and the target temperature, so that the estimated paper temperature before flipping is within the range of the target temperature.

[0322] Then, if it is determined that the estimated paper temperature falls within the target temperature range, the process proceeds to step S6.

[0323] Furthermore, when the paper is transported by the printing cylinder (321) before being flipped over, the control unit (40) can estimate whether the paper temperature at the image formation position is actually within the target temperature range based on the detection results of the temperature sensors (m3) and (m4).

[0324] Therefore, the control unit (40) may feed back the detection results of the temperature sensor (m3) and temperature sensor (m4) to the temperature adjustment of the paper on which the image will be formed.

[0325] <Step S6> The control unit (40) starts monitoring the output (detection signal) of each temperature sensor used for temperature detection of the printing cylinder (321) and the temperature control supply cylinder (313), and stores the detected temperature.

[0326] <Step S7> Next, the control unit (40) estimates the paper temperature at the image formation position after inversion, that is, the position on the printing cylinder (321) facing the inkjet recording unit, based on the value stored in step S6 and the various image formation conditions described above (such as surface ink amount).

[0327] In one specific example, the control unit (40) determines the amount of curing heat energy generated and the rise in the surface temperature of the paper [°C] based on the amount of surface ink ejected (landed) on the paper and the characteristics of the image (such as the position where it is recorded).

[0328] The control unit (40) then adds the amount of temperature rise to the paper temperature at the image formation position before inversion, which was estimated in step S4, in order to estimate the paper temperature immediately after the active rays were irradiated by the ink curing and drying device (323) and before inversion.

[0329] Next, the control unit (40) estimates the paper temperature at the image formation position after inversion, based on the estimated paper temperature immediately after irradiation with the active rays and before flipping, the temperatures of the temperature control supply cylinder (313) and printing cylinder (321) detected by each temperature sensor, the basis weight of the paper which is an indicator of heat retention, and the temperature detected by temperature sensors (not shown) inside the machine.

[0330] <Step S8> The control unit (40) changes the set temperature of the temperature control member, etc., so that the estimated paper temperature after flipping the paper over is within the range of the target temperature.

[0331] More specifically, if the estimated paper temperature at the image formation position after inversion exceeds the upper limit of the target temperature, the control unit (40) will lower the set temperature of the temperature control components, etc., using the method described above. This will involve increasing the airflow of the blower fan to blow cool air onto the rollers with built-in temperature control devices, or lowering the set temperature of the thermoelectric conversion device.

[0332] Conversely, if the estimated paper temperature at the image formation position after inversion exceeds the lower limit of the target temperature, the control unit (40) will lower the airflow of the blower fan and apply warm air, or raise the set temperature of the thermoelectric conversion device, in order to lower the cooling capacity of the blower fan, roller with a built-in temperature control device, etc.

[0333] Furthermore, when the paper is transported by the printing cylinder (321) after being flipped over, the control unit (40) can estimate whether the paper temperature at the image formation position is actually within the target temperature range based on the detection results of the temperature sensors (m3) and (m4).

[0334] Therefore, the control unit (40) may feed back the detection results of the temperature sensors (m3) and (m4) to the temperature adjustment of the paper on which the double-sided image will be formed.

[0335] <Step S9> Next, the control unit (40) controls the supply devices (221, 223, 231, 311, 312), etc., to start the paper supply operation to the temperature control mechanism.

[0336] Through the control described above, the paper supplied from the supply device passes through the first part (313a) of the temperature control mechanism.

[0337] At this time, the paper is transported by the first part (313a) and its temperature is adjusted to the desired temperature by the method described above.

[0338] Furthermore, the leading edge in the transport direction is supported and transported by one of the claw portions (321a) of the printing cylinder (321) which is rotating counterclockwise (direction F2) in Figure 1.

[0339] <Step S10> The control unit (40) sets the transport path to the side of the resupply mechanism (331, 332, 333).

[0340] <Step S11> Next, the control unit (40) sequentially drives the Y, M, C, and K heads (322a, 322b, 322c, 322d) to eject ink from the corresponding heads and perform the process of forming an image on the paper.

[0341] <Step S12> Next, the control unit (40) drives and controls the ink curing and drying device (323) to irradiate the paper on which the image has been formed with active rays.

[0342] <Step S13> Subsequently, the control unit (40) irradiates the paper with an active light and then performs the process of inverting the paper.

[0343] In other words, the control unit (40) controls the transfer of one end (the leading edge in the transport direction) of the paper carried on the printing cylinder (321) from one of the claw portions (321a) of the printing cylinder (321) to the claw portion (331a) of the first reversing cylinder (331).

[0344] The control unit (40) then controls the independent drive motor at a predetermined speed corresponding to the length of the recording medium (P) in the transport direction, so that after the leading end of the paper carried on the claw portion (331a) of the first reversing cylinder (331) of the resupply mechanism (331, 332, 333) in Figure 1 passes position F where it contacts the reversing swing device (333), the rear end of the paper reaches position F at the same time that the reversing swing device (333) reaches position F.

[0345] As the reversing swing device (333) passes through position F, it grasps the rear end of the recording medium (P) with a cam mechanism (not shown), swings, and hands it over to the second reversing cylinder (332). This action causes the paper to be flipped over.

[0346] <Step S14> The control unit (40) controls the temperature of the temperature-controlled supply cylinder (313) by referring to the temperature detected by each temperature sensor and adjusting it with a temperature control component, and supplies paper from the second reversing cylinder (332) of the resupply mechanism (331, 332, 333) to the temperature control mechanism.

[0347] In step S16, the paper transport direction is reversed, and thereafter, the paper is transferred from the second reversing cylinder (332) of the resupply mechanism to the second part (313b) of the temperature control mechanism, with the front and back sides and the leading and trailing ends of the transport direction reversed compared to when the front side was printed.

[0348] <Step S15> Next, the control unit (40) controls the temperature of the printing cylinder (321) by referring to the temperature detected by each temperature sensor and adjusting it using a temperature control component, and supplies paper from the temperature control mechanism to the printing cylinder (321).

[0349] At this time, the paper is transported by the second part (313b) and its temperature is adjusted to the desired temperature by the method described above.

[0350] The paper is then transported by the printing cylinder (321) toward the image forming unit (322).

[0351] <Steps S16, S17 and S18> Next, the control unit (40) performs a process to set the transport path (the open / closed state of each claw as described above) to the discharge device side, and after performing control of image formation and active ray irradiation on the back side of the paper, proceeds to step S22.

[0352] <Step S19> Subsequently, the control unit (40) controls the transport of the paper, which has undergone the above-mentioned active ray irradiation treatment and is supported on the printing cylinder (321), to the first discharge cylinder (411), and then to the second discharge cylinder (412), and from the second discharge cylinder (412) to the discharge chain (415) driven by a plurality of gears (413).

[0353] <End> Through this control, the paper on which a full-color image has been formed using Y, M, C, and K inks is transported to the output unit (420) and placed on the output tray (431). Then, after the torso rotation stops, the process ends. [Explanation of Symbols]

[0354] 10. Data Input Section 20 Conveyor Route Switching Process Section 30 Head drive unit 40 Control Unit 80 Temperature detection unit 100 Image forming apparatus 220 Supply section 221 Roller 223 Supply belt 231 Supply Tray 311 No. 1 supply shell 312 Second supply shell 313 Temperature-controlled supply unit 313a First part 313ah hole 313b Second part 313bh hole 313c Claw part 314 Body, which is part of the temperature control mechanism 321 Printing Cylinder 321a Claw part 322 Image forming unit 322a, 322b, 322c, 322d heads 323 Ink curing and drying equipment 331 First Reversible Torso 331a Claw part 332 Second Reversible Torso 332a Claw part 333 Reversing Swing Device 411 First ejection drum 411a Claw part 412 Second ejection drum 412a Claw part 413, 414 sprockets 415 Exhaust chain 415a Claw part 416 Guide Roller 420 Discharge section 431 Discharge Tray P recording medium H1, H2 heaters

Claims

1. A transport unit that carries and transports the recording medium, An image forming unit that forms an image on the recording medium transported by the transport unit, A temperature control mechanism that supplies the recording medium to the transport unit while adjusting its temperature, A supply device for supplying the recording medium to the temperature control mechanism, A discharge device for discharging the recording medium that has been transported from the transport unit and on which an image has been formed in the image forming unit, A resupply mechanism that supplies the recording medium, which has been transported from the transport unit and on which an image has been formed in the image forming unit, to the temperature control mechanism, An image forming apparatus comprising means for switching whether to transport the recording medium, which has been transported from the transport unit and on which an image has been formed in the image forming unit, to the discharge device or to the resupply mechanism, The temperature control mechanism includes a first part that transports the recording medium supplied from the supply device, It has a second part for transporting the recording medium supplied from the resupply mechanism, The system further comprises a temperature control unit capable of adjusting the first and second parts to different temperatures. An image forming apparatus characterized by the following features.

2. The temperature control unit includes means for heating at least one of the first portion and the second portion. The image forming apparatus according to feature 1.

3. The heating means is a means of heating by supplying a heat transfer medium having different materials for the first part and the second part. The image forming apparatus according to feature 2.

4. The heating means is a means of heating by supplying a heat transfer medium having different temperatures in the first part and the second part. The image forming apparatus according to feature 2.

5. The heating means is a means of heating by supplying different amounts of a heat transfer medium to the first part and the second part. The image forming apparatus according to feature 2.

6. The heating means is a means of heating by supplying radiant heat. The image forming apparatus according to feature 2.

7. The heating means is a means of heating by supplying radiant heat of different intensities to the first part and the second part. The image forming apparatus according to feature 2.

8. The heating means is a means of heating by supplying radiant heat to the first part and the second part at different times. The image forming apparatus according to feature 2.

9. The temperature control unit includes means for cooling at least one of the first portion and the second portion. The image forming apparatus according to feature 1.

10. The means for cooling is a means for supplying a refrigerant to at least one of the first part and the second part to cool it. The image forming apparatus according to feature 9.

11. The cooling means is a means of supplying a refrigerant at different temperatures to the first part and the second part for cooling. The image forming apparatus according to feature 9.

12. The cooling means is a means of supplying different amounts of refrigerant to the first part and the second part for cooling. The image forming apparatus according to feature 9.

13. The resupply mechanism is a mechanism that directly transfers the recording medium to the second part. The image forming apparatus according to feature 1.

14. The temperature control mechanism has a temperature control supply cylinder that supports and rotates the recording medium to supply it to the transport section, and the first part and the second part are parts of the temperature control supply cylinder. The image forming apparatus according to feature 1.

Images