Cleaning body, unit, charging device, assembly, and image forming apparatus

Abstract

To provide a cleaning body that prevents dirt from adhering to the surface of the object to be cleaned, and that maintains its ability to adhere to the object to be cleaned for a long period of time. [Solution] The cleaning body 100 has a core body 102, a foamed elastic layer 104, and an adhesive layer 106, wherein the 25% compressive load of the foamed elastic layer 104 in the high-action region is 1 / 2 or less of the 25% compressive load of the foamed elastic layer 104 in the low-action region.

Description

[Technical Field]

[0001] This disclosure relates to cleaning bodies, units, charging devices, assemblies, and image forming apparatuses. [Background technology]

[0002] Patent Document 1 discloses an image forming apparatus comprising a rotating image carrier, a charging roll that presses against the image carrier and rotates with it to charge the image carrier, and a cleaning roll that presses against the charging roll and rotates with it to clean the charging roll, wherein the cleaning roll has a core material whose ends are rotatably supported and a cleaning member made of a roll-shaped porous elastic material provided on the circumferential surface of the core material, and the axial end of the cleaning member is thicker than the central part. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2007-334246 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] The present disclosure aims to provide a cleaning body that, compared to a cleaning body where there is no difference between the 25% compressive load of the foamed elastic layer in the high-action region and the 25% compressive load of the foamed elastic layer in the low-action region, is less likely to cause dirt to adhere to the surface of the object to be cleaned, and maintains its adherence to the object to be cleaned for a long period of time. [Means for solving the problem]

[0005] The following embodiments are included as specific means for solving the aforementioned problems. <1> The core body, On the outer circumferential surface of the core, a foamed elastic layer is arranged, wound in a spiral shape from one end to the other of the core. It has an adhesive layer that bonds the core body and the foamed elastic layer, The 25% compressive load of the foamed elastic layer in the high-action region is less than or equal to half the 25% compressive load of the foamed elastic layer in the low-action region. Cleaning unit. <2> The 25% compressive load of the foamed elastic layer in the high-action region is 1 / 3 or less of the 25% compressive load of the foamed elastic layer in the low-action region. <1> The cleaning body described above. <3> The 25% compressive load of the foamed elastic layer in the high-action region is 0.5 kPa or more and 1.5 kPa or less. <1> or <2> The cleaning body described above. <4> The 25% compressive load of the foamed elastic layer in the low-acting region is 1.5 kPa or more and 4.5 kPa or less. <1> ~ <3> A cleaning body as described in any one of the following. <5> The object to be cleaned and, <1> ~ <4> A cleaning body according to any one of the above, comprising a cleaning body that rotates in contact with the rotating object to be cleaned and cleans the object to be cleaned, unit. <6> A charged body and <1> ~ <4> A cleaning body according to any one of the above, comprising a cleaning body that rotates in contact with the rotating charged body and cleans the charged body, A charging device. <7> The charged object and, A charged body that charges the object to be charged, <1> ~ <4> A cleaning body according to any one of the above, comprising a cleaning body that rotates in contact with the rotating charged body and cleans the charged body, The charged object, the charged object, and the cleaning object are assembled to be detachably attached to the main body of the device. assembly. <8> Photoreceptor and A charging body for charging the photoreceptor, An exposure apparatus that exposes the charged photoreceptor to form an electrostatic image, A developing apparatus for developing the electrostatic charge image formed on the photoreceptor, <1> ~ <4> A cleaning body according to any one of the above, comprising a cleaning body that rotates in contact with the rotating charged body and cleans the charged body, Image forming apparatus. [Effects of the Invention]

[0006] <1> According to this, compared to a cleaning body where there is no difference between the 25% compressive load of the foamed elastic layer in the high-action region and the 25% compressive load of the foamed elastic layer in the low-action region, a cleaning body is provided in which dirt is less likely to adhere to the surface of the object to be cleaned, and in which the ability to adhere to the object to be cleaned is maintained for a long period of time. <2> According to this, compared to a cleaning body in which the 25% compressive load of the foamed elastic layer in the high-action region is more than 1 / 3 of the 25% compressive load of the foamed elastic layer in the low-action region, a cleaning body is provided in which dirt is less likely to adhere to the surface of the object to be cleaned, and in which the ability to follow the object to be cleaned is maintained for a long period of time. <3> According to the report, compared to cleaning bodies in which the 25% compressive load of the foamed elastic layer in the high-action region is less than 0.5 kPa or greater than 1.5 kPa, a cleaning body is provided in which dirt is less likely to adhere to the surface of the object to be cleaned, and in which the ability to follow the object to be cleaned is maintained for a long period of time. <4> According to the report, compared to cleaning bodies in which the 25% compressive load of the foamed elastic layer in the low-acting region is less than 1.5 kPa or greater than 4.5 kPa, a cleaning body is provided in which dirt is less likely to adhere to the surface of the object to be cleaned, and in which the ability to follow the object to be cleaned is maintained for a long period of time. <5> According to this, compared to a unit having a cleaning body where there is no difference between the 25% compressive load of the foamed elastic layer in the high-action region and the 25% compressive load of the foamed elastic layer in the low-action region, a unit is provided in which dirt is less likely to adhere to the surface of the object to be cleaned, and in which the obedience of the cleaning body to the object to be cleaned is maintained for a long period of time. <6> According to the findings, compared to a charging device having a cleaning body where there is no difference between the 25% compressive load of the foamed elastic layer in the high-action region and the 25% compressive load of the foamed elastic layer in the low-action region, a charging device is provided in which dirt is less likely to adhere to the surface of the charging body, and the obedience of the cleaning body to the charging body is maintained for a long period of time. According to <7>, compared with an assembly having a cleaning body in which there is no difference between the 25% compression load of the foamed elastic layer in the high-action region and the 25% compression load of the foamed elastic layer in the low-action region, dirt adheres less firmly to the surface of the charging body, and an assembly is provided in which the followability of the cleaning body to the charging body is maintained for a long period of time. According to <8>, compared with an image forming apparatus having a cleaning body in which there is no difference between the 25% compression load of the foamed elastic layer in the high-action region and the 25% compression load of the foamed elastic layer in the low-action region, dirt adheres less firmly to the surface of the charging body, and an image forming apparatus is provided in which the followability of the cleaning body to the charging body is maintained for a long period of time.

Brief Description of the Drawings

[0007] [Figure 1] It is a schematic perspective view showing an example of the cleaning body according to the present embodiment. [Figure 2] It is a schematic plan view showing an example of the cleaning body according to the present embodiment. [Figure 3] It is a schematic cross-sectional view obtained by cutting an example of the cleaning body according to the present embodiment parallel to the radial direction of the core body. [Figure 4A] It is a process diagram showing an example of the manufacturing method of the cleaning body according to the present embodiment. [Figure 4B] It is a process diagram showing an example of the manufacturing method of the cleaning body according to the present embodiment. [Figure 4C] It is a process diagram showing an example of the manufacturing method of the cleaning body according to the present embodiment. [Figure 5] It is a schematic configuration diagram showing an example of the image forming apparatus according to the present embodiment. [Figure 6] It is a schematic configuration diagram showing an example of the assembly according to the present embodiment. [Figure 7] It is a schematic configuration diagram obtained by enlarging the peripheral portion of the charging device in FIGS. 5 and 6.

Modes for Carrying Out the Invention

[0008] Hereinafter, embodiments of the present disclosure will be described. These descriptions and examples are illustrative of the embodiments and do not limit the scope of the embodiments.

[0009] In this disclosure, the numerical range indicated using "~" represents a range that includes the numbers before and after "~" as the minimum and maximum values, respectively. In numerical ranges described in stages within this disclosure, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Furthermore, in numerical ranges described within this disclosure, the upper or lower limit of that range may be replaced with the values ​​shown in the examples.

[0010] In this disclosure, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes, provided that their objectives are achieved.

[0011] When embodiments are described in this disclosure with reference to the drawings, the configuration of such embodiments is not limited to the configuration shown in the drawings. The sizes of the components in each figure are conceptual, and the relative relationships between the components are not limited thereto. Components having the same function and operation may be given the same reference numerals throughout the drawings, and their descriptions may be omitted.

[0012] In this disclosure, each component may contain multiple types of the corresponding substance. When referring to the amount of each component in a composition in this disclosure, if there are multiple types of the substance corresponding to each component in the composition, it means the total amount of those multiple types of substances present in the composition unless otherwise specified. In this disclosure, each component may contain multiple types of particles. If multiple types of particles corresponding to each component are present in the composition, the particle size of each component refers to the value for a mixture of such multiple types of particles present in the composition, unless otherwise specified.

[0013] <Cleaning> The structure of the cleaning body according to this embodiment will be described with reference to the drawings. Figure 1 is a schematic perspective view showing an example of a cleaning body according to this embodiment. Figure 2 is a schematic plan view showing an example of a cleaning body according to this embodiment. Figure 2 is a plan view of Figure 1.

[0014] The cleaning body 100 shown in Figures 1 and 2 is a component comprising a core body 102, a foamed elastic layer 104, and an adhesive layer 106. Figure 3 is a cross-sectional view of the cleaning body 100 cut parallel to the radial direction of the core body 102 (i.e., a cross-sectional view in the AA direction of Figure 2).

[0015] The cleaning body 100 is a component that contacts the object to be cleaned and rotates in accordance with the object to be cleaned. The cleaning body 100 may be either a component that is always in contact with the object to be cleaned and rotates in accordance with the object to be cleaned, or a component that is only in contact with the object to be cleaned and rotates in accordance with the object to be cleaned.

[0016] The core body 102 is a rod-shaped or cylindrical member.

[0017] The foamed elastic layer 104 is a layer formed by spirally winding a strip-shaped foamed elastic member, and is arranged spirally at intervals on the outer surface of the core body 102 from one end to the other. The foamed elastic layer 104 spirally wound around the core body 102 may be right-handed or left-handed.

[0018] The core body 102 and the foamed elastic layer 104 are bonded together by an adhesive layer 106. The adhesive layer 106 has, for example, approximately the same width and length as the foamed elastic layer 104.

[0019] The foamed elastic layer 104 of the cleaning body 100 comes into contact with the surface of the object to be cleaned. The foamed elastic layer 104 exhibits cleaning performance with respect to the object to be cleaned.

[0020] In this disclosure, the high-performance region of the cleaning body means the region in which the foamed elastic layer is in contact with the object to be cleaned and in which the foamed elastic layer is required to exhibit cleaning performance toward the object to be cleaned. The high-performance region of the cleaning body is usually a continuous area including the central part in the axial direction of the cleaning body. In this disclosure, the low-action region of the cleaning body means a region in which the foamed elastic layer is in contact with the object to be cleaned, but where the foamed elastic layer does not need to exhibit cleaning performance toward the object to be cleaned, or where the need to exhibit cleaning performance is lower compared to the high-action region. The low-action region of the cleaning body is usually a part of one or both ends of the cleaning body in the axial direction. In this disclosure, the term "low-action region" means a region where it is not necessary or not necessary to demonstrate performance, and does not mean a region with no performance or low performance. The low-action region of the cleaning body may or may not demonstrate cleaning performance toward the object to be cleaned.

[0021] The high-action region and low-action region of the cleaning body 100 will be explained using the example of a configuration where the object to be cleaned is a charged body in an electrophotographic image forming apparatus. In this explanation, the central part, one end, and both ends refer to the parts in the axial direction of the cleaning body, the charged body, and the photoreceptor. Contamination originating from toner particles, toner additives, and discharge products accumulates on the surface of the charged body. When this contamination adheres to the discharge area of ​​the charged body, uneven charging occurs on the photoreceptor, resulting in uneven density in the image formed on the recording medium. Therefore, the discharge area of ​​the charged body needs to be cleaned by the cleaning body 100. However, the axial length of the discharge region of the charged element may be longer than the axial length of the image-forming region of the photoreceptor (the region where the toner image is formed by the developer). Furthermore, a non-discharge region may exist outside the discharge region of the charged element, continuous with the discharge region. Therefore, at one or both ends of the outer surface of the charged body, there are discharge areas facing the non-image-forming area of ​​the photoreceptor (the area where a toner image is not formed), or non-discharge areas. Of the outer surface of the charged body, the discharge areas facing the non-image-forming area of ​​the photoreceptor and the non-discharge areas do not need to be cleaned by the cleaning body 100, or the need to be cleaned is lower compared to the discharge area in the center. In the above configuration, the highly effective region of the cleaning body 100 is the region that contacts the outer surface of the charged body, and specifically the region that contacts the outer surface of the charged body that faces the image-forming region of the photoreceptor. In other words, the highly effective region of the cleaning body 100 is the region that faces the image-forming region of the photoreceptor with the charged body in between. The low-operating region of the cleaning body 100 is the region that contacts the outer surface of the charged body, specifically the outer surface of the charged body that faces the non-image-forming region of the photoreceptor, and / or the outer surface of the charged body that is a non-discharge region. In other words, the low-operating region of the cleaning body 100 is the region that faces the non-image-forming region of the photoreceptor with the charged body in between, and / or the region that faces the non-discharge region of the outer surface of the charged body.

[0022] Examples of objects to be cleaned by the cleaning body 100 in an electrophotographic image forming apparatus include charged bodies, photoreceptors, transfer members, paper transport belts, secondary transfer members in an intermediate transfer system, and intermediate transfer bodies in an intermediate transfer system. The axial lengths of the high-working region and low-working region of the cleaning body 100 are determined according to the overall axial length of the object to be cleaned and the axial length of the region in which the function is performed. For example, if the object to be cleaned by the cleaning body 100 is a charged object in an electrophotographic image forming apparatus for office use, the cleaning body 100 has a high working area in the center and low working areas at both ends. An example of each area of ​​the cleaning body 100 in this configuration is the low working area / high working area / low working area = 0mm~25mm / 25mm~325mm / 325mm~350mm, starting from one end.

[0023] The cleaning body 100 has a 25% compressive load of the foamed elastic layer 104 in the high-action region that is less than or equal to half the 25% compressive load of the foamed elastic layer 104 in the low-action region. With the cleaning body 100, dirt is less likely to adhere to the surface of the object to be cleaned, and its adherence to the object to be cleaned is maintained for a long period of time. The mechanism is presumed to be as follows.

[0024] The adhesion of dirt to the surface of the object to be cleaned occurs when the cleaning body 100 rubs dirt that it cannot completely remove onto the object to be cleaned. From the viewpoint of suppressing the adhesion of dirt to the surface of the object to be cleaned, it is preferable that the foamed elastic layer 104 of the cleaning body 100 be relatively soft. However, if the foamed elastic layer 104 is soft, the mechanical strength of the foamed elastic layer 104 will decrease over time, and its ability to adhere to the object to be cleaned will not be maintained. Therefore, the foamed elastic layer 104 in the high-action region of the cleaning body 100 is made relatively soft, and the foamed elastic layer 104 in the low-action region is made relatively hard. Because the foamed elastic layer 104 in the high-action region is softer, dirt is less likely to adhere to the surface of the area of ​​the object being cleaned where it performs its function. On the other hand, because the foamed elastic layer 104 in the low-action region is harder, that region maintains its mechanical strength, and the mobility of the cleaning body 100 to the object being cleaned is maintained for a long period of time.

[0025] Based on the above technical concept, this embodiment uses the 25% compression load, which is widely used as an indicator of hardness, cushioning, and shock absorption of foamed elastic materials, as an indicator, and sets the 25% compression load of the foamed elastic layer 104 in the high-action region to half or less (i.e., 1 / 2 or less) of the 25% compression load of the foamed elastic layer 104 in the low-action region. If the 25% compressive load of the foamed elastic layer 104 in the high-action region of the cleaning body 100 is greater than half the 25% compressive load of the foamed elastic layer 104 in the low-action region, then the foamed elastic layer 104 in the high-action region is not soft enough, or the foamed elastic layer 104 in the low-action region is not hard enough, so dirt adheres to the surface of the object to be cleaned, or the ability to follow the object to be cleaned is not maintained. In order for dirt to adhere less to the surface of the object to be cleaned and for the ability to follow the object to be cleaned to be maintained for a long period of time, the cleaning body 100 has a 25% compressive load of the foamed elastic layer 104 in the high-action region that is half or less the 25% compressive load of the foamed elastic layer 104 in the low-action region.

[0026] The method for measuring the 25% compressive load of the foamed elastic layer 104 is as follows. Remove the foamed elastic layer 104 from the core 102, flatten it as much as possible to remove any curl, and obtain a strip-shaped member. If the adhesive layer 106 is attached to the strip-shaped member, remove the adhesive layer 106. Alternatively, prepare a strip-shaped member to be used for forming the foamed elastic layer 104. A test specimen for the high-action region is cut from the center of the strip-shaped member, and a test specimen for the low-action region is cut from the end of the strip-shaped member. The size of the test specimen is 10 mm in length, and its width and thickness are the width and thickness of the strip-shaped member itself. Before testing, the test specimens are placed in an environment with a temperature of 23°C and a relative humidity of 55% for at least one day. A compression test is performed in the same environment, and the load (Pa) at 25% compression is measured. Specifically, the thickness direction of the test specimen is aligned with the compression direction, the test specimen is placed between the compression fixture (two parallel plates) of a universal testing machine, the Strograph (Toyo Seiki Seisakusho Co., Ltd.), and compressed at a speed of 0.5 mm / min, and the load (Pa) at 25% compression is measured.

[0027] The 25% compressive load of the foamed elastic layer 104 in the high-action region is less than or equal to half, and preferably less than or equal to one-third, of the 25% compressive load of the foamed elastic layer 104 in the low-action region. The 25% compressive load of the foamed elastic layer 104 in the high-action region is preferably 1 / 5 to 1 / 2, more preferably 1 / 5 to 1 / 3, and even more preferably 1 / 4 to 1 / 3, from the viewpoint of achieving a good balance between suppressing the adhesion of dirt to the surface of the object to be cleaned and maintaining the mobility of the cleaning body 100 to the object to be cleaned.

[0028] The 25% compressive load of the foamed elastic layer 104 in the high-action region is preferably 1.5 kPa or less, more preferably 1.4 kPa or less, and even more preferably 1.2 kPa or less, from the viewpoint of preventing dirt from adhering to the surface of the object to be cleaned. The 25% compressive load of the foamed elastic layer 104 in the high-action region is preferably 0.5 kPa or more, more preferably 0.6 kPa or more, and even more preferably 0.8 kPa or more, from the viewpoint of maintaining the obedience of the cleaning body 100 to the object to be cleaned for a long period of time.

[0029] The 25% compressive load of the foamed elastic layer 104 in the low-acting region is preferably 1.5 kPa or more, more preferably 2.0 kPa or more, and even more preferably 2.5 kPa or more, from the viewpoint of maintaining the obedience of the cleaning body 100 to the object to be cleaned for a long period of time. The 25% compressive load of the foamed elastic layer 104 in the low-acting region is preferably 4.5 kPa or less, more preferably 4.0 kPa or less, and even more preferably 3.5 kPa or less, from the viewpoint of preventing dirt from adhering to the surface of the object to be cleaned.

[0030] To control the 25% compressive load of the foamed elastic layer 104 in the high-action region to less than half of the 25% compressive load of the foamed elastic layer 104 in the low-action region, for example, a relatively soft foamed elastic material is used as the base material for the foamed elastic layer 104, while reinforcing the low-action region. Details of the reinforcing process will be described later.

[0031] The specific forms of the core body 102, the foamed elastic layer 104, and the adhesive layer 106 will be described below.

[0032] The diameter of the core body 102 is preferably 2 mm or more and 12 mm or less, more preferably 3 mm or more and 10 mm or less, and even more preferably 4 mm or more and 8 mm or less.

[0033] The helical angle θ of the foamed elastic layer 104 is preferably greater than 15° and less than or equal to 45°, from the viewpoint of preventing the foamed elastic layer 104 from peeling off the adhesive layer 106 and from the viewpoint of providing excellent cleaning performance for the object to be cleaned. The helical angle θ refers to the angle (acute angle) at which the longitudinal direction P (helical direction) of the foamed elastic layer 104 and the axial direction Q of the core body 102 intersect, as shown in Figure 2. When the helical angle θ is greater than 15°, resistance is less likely to be encountered when in contact with the object to be cleaned, and peeling of the foamed elastic layer 104 is suppressed. Also, when the helical angle θ is greater than 15°, the number of turns of the foamed elastic layer 104 is relatively large, resulting in excellent cleaning performance of the object to be cleaned. From these viewpoints, a helical angle θ of 18° or more is more preferable, and 20° or more is even more preferable. When the helical angle θ is 45° or less, the deformation and restoring force of the foamed elastic layer 104 are suppressed, and peeling of the foamed elastic layer 104 is inhibited. From this viewpoint, the helical angle θ is more preferably 40° or less, and even more preferably 35° or less.

[0034] The number of turns of the foamed elastic layer 104 around the core 102 is preferably 3 or more, more preferably 4 or more, and even more preferably 5 or more, from the viewpoint of excellent cleaning performance of the object to be cleaned and from the viewpoint of the cleaning body 100 being easily driven to rotate by the object to be cleaned. The upper limit of the number of turns of the foamed elastic layer 104 is not particularly limited as it depends on the length of the core 102.

[0035] From the viewpoint of excellent cleaning performance of the object to be cleaned, the coverage rate of the foamed elastic layer 104 on the core body 102 is preferably 30% or more, more preferably 35% or more, and even more preferably 40% or more. The coverage rate of the foamed elastic layer 104 on the core body 102 is preferably 70% or less, more preferably 65% ​​or less, and even more preferably 55% or less, from the viewpoint of suppressing the re-migration of deposits adhering to the surface of the foamed elastic layer 104 to the object to be cleaned. The coverage ratio is defined as {width W1 of the foamed elastic layer 104 ÷ (width W1 of the foamed elastic layer 104 + spacing W2 of the foamed elastic layer 104)}. The width W1 and spacing W2 of the foamed elastic layer 104 refer to the length of the foamed elastic layer 104 and the distance between the foamed elastic layers 104 along the axial direction Q of the core body 102, as shown in Figure 2.

[0036] The width W1 of the foamed elastic layer 104 is preferably 5 mm or more and 25 mm or less, more preferably 6 mm or more and 20 mm or less, and even more preferably 8 mm or more and 15 mm or less.

[0037] The cleaning body 100 may have multiple (e.g., two) foamed elastic layers 104. Multiple (e.g., two) foamed elastic layers 104 are independent layers formed by multiple (e.g., two) strip-shaped foamed elastic members spirally wound around the outer surface of the core body 102. The multiple foamed elastic layers 104 may be spaced apart from each other, or their longitudinal edges may be in contact with each other. By providing multiple independent foamed elastic layers 104, the cleaning performance of the cleaning body 100 is improved.

[0038] When the cleaning body 100 has multiple foamed elastic layers 104, for each of the multiple foamed elastic layers 104, the 25% compressive load of the foamed elastic layer 104 in the high-action region is 1 / 2 or less of the 25% compressive load of the foamed elastic layer 104 in the low-action region, preferably 1 / 5 or more and 1 / 2 or less, more preferably 1 / 5 or more and 1 / 3 or less, and even more preferably 1 / 4 or more and 1 / 3 or less.

[0039] When the cleaning body 100 has multiple foamed elastic layers 104, the 25% compressive load of the foamed elastic layer 104 in the high-action region for each of the multiple foamed elastic layers 104 is preferably 0.5 kPa or more and 1.5 kPa or less, more preferably 0.6 kPa or more and 1.4 kPa or less, and even more preferably 0.8 kPa or more and 1.2 kPa or less. When the cleaning body 100 has multiple foamed elastic layers 104, the 25% compressive load of the foamed elastic layer 104 in the low-action region for each of the multiple foamed elastic layers 104 is preferably 1.5 kPa or more and 4.5 kPa or less, more preferably 2.0 kPa or more and 4.0 kPa or less, and even more preferably 2.5 kPa or more and 3.5 kPa or less.

[0040] If the cleaning body 100 has multiple foamed elastic layers 104, the adhesive layer 106 may be a separate layer for each of the multiple foamed elastic layers 104, or it may be a single layer on which the multiple foamed elastic layers 104 are placed.

[0041] The cleaning body 100 may have an area at its axial end that does not need to come into contact with the object to be cleaned. In that case, the foamed elastic layer 104 does not need to be placed at the end of the cleaning body 100.

[0042] The materials of the core 102, the foamed elastic layer 104, and the adhesive layer 106 are described below.

[0043] [Core body 102] The core body 102 can be made of metal, alloy, or resin. Examples of metals or alloys include iron (free-cutting steel, etc.), copper, brass, aluminum, nickel, and other metals; and stainless steel and other alloys. Examples of resins include polyacetal resin and polycarbonate resin. One type of resin may be used alone, or two or more types may be used in combination.

[0044] The core body 102 may have a surface treatment. If the core body 102 is made of metal, plating is desirable. If the core body 102 is made of a non-conductive material (e.g., resin), a conductive treatment such as plating may be performed.

[0045] [Foam elastic layer 104] The foamed elastic layer 104 is preferably a layer that returns to its original shape even when deformed by an external force of 100 Pa.

[0046] Examples of materials for the foamed elastic layer 104 include foaming resins such as polyurethane, polyethylene, polyamide, and polypropylene; and rubber materials such as silicone rubber, fluororubber, urethane rubber, EPDM (ethylene propylene diene rubber), NBR (acrylonitrile-butadiene rubber), CR (chloroprene rubber), chlorinated polyisoprene, isoprene, styrene-butadiene rubber, hydrogenated polybutadiene, and butyl rubber. These materials may be used individually or in combination of two or more. These materials may also contain foaming agents, foaming aids, foam stabilizers, catalysts, curing agents, plasticizers, vulcanizing agents, vulcanizing aids, and vulcanization accelerators.

[0047] From the viewpoint of preventing scratches on the surface of the object to be cleaned due to friction, and from the viewpoint of suppressing tearing and damage over a long period of time, it is desirable that the foamed elastic layer 104 be made of foamed polyurethane that is resistant to tension.

[0048] Examples of foamed polyurethanes include reaction products of polyols (e.g., polyester polyols, polyether polyols, acrylic polyols, etc.) and isocyanates (e.g., 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4-diphenylmethane diisocyanate, tolidine diisocyanate, 1,6-hexamethylene diisocyanate, etc.), and may also be reaction products obtained by further reacting with chain extenders (1,4-butanediol, trimethylolpropane). Foaming of polyurethanes is generally carried out using foaming agents such as water or azo compounds (e.g., azodicarbonamide, azobisisobutyronitrile, etc.). Foaming aids, foam stabilizers, catalysts, etc. may be added to the foamed polyurethane.

[0049] The density of the foamed elastic layer 104 is 60 kg / m³ 3More than 100kg / m 3 The following is preferable: 65 kg / m 3 More than 95kg / m 3 The following is more preferable: 70 kg / m 3 More than 90kg / m 3 The following is even more preferable.

[0050] The number of cells in the foamed elastic layer 104 is preferably 80 cells / 25 mm or more and 105 cells / 25 mm or less, more preferably 85 cells / 25 mm or more and 100 cells / 25 mm or less, and even more preferably 90 cells / 25 mm or more and 95 cells / 25 mm or less. The number of cells in the foamed elastic layer 104 is determined in accordance with JIS K 6400-1:2004 (Annex 1).

[0051] [Adhesive layer 106] The material of the adhesive layer 106 is not particularly limited as long as it can bond the core body 102 and the foamed elastic layer 104. Examples of adhesive layers 106 include double-sided tape and adhesives.

[0052] [Method for manufacturing the cleaning unit 100] Figures 4A, 4B, and 4C are process diagrams showing an example of a manufacturing method for the cleaning body 100.

[0053] First, a foamed elastic material (e.g., foamed polyurethane) is sliced ​​to the desired thickness to obtain a rectangular foamed elastic sheet (e.g., a foamed polyurethane sheet). A UV-curable resin is impregnated into the vicinity of one of the two pairs of opposite sides of the foamed elastic sheet. The region impregnated with the UV-curable resin is the region that will be at both ends in the axial direction when the cleaning body 100 is manufactured, and corresponds to the low-activity region of the foamed elastic layer 104. Next, the foamed elastic sheet is irradiated with ultraviolet light to cure the ultraviolet-curing resin. In this way, reinforcement processing is performed on the region of the foamed elastic layer 104 that corresponds to the low-action region.

[0054] The degree of reinforcement is adjusted so that the 25% compressive load in the reinforced area is at least twice (preferably three times or more) the 25% compressive load in the unreinforced area. The degree of reinforcement can be adjusted by the type and amount of UV-curing resin used for impregnation. The 25% compressive load in the area without reinforcement (i.e., the 25% compressive load of the foamed elastic sheet itself) is preferably between 0.5 kPa and 1.5 kPa. The 25% compressive load in the reinforced area is preferably between 1.5 kPa and 4.5 kPa. The 25% compressive load in each region here is the value measured according to the aforementioned sample and measurement method related to the 25% compressive load of the foamed elastic layer 104.

[0055] Next, double-sided tape is attached to one side of the foamed elastic sheet. A strip-shaped foamed elastic member having the desired length and width is cut from the foamed elastic sheet with the double-sided tape attached. The double-sided tape may also be attached to one side after the strip-shaped foamed elastic member has been cut from the foamed elastic sheet. Through the above process, a strip-shaped member (see Figure 4A) is obtained in which double-sided tape 100D is attached to one side of the strip-shaped foamed elastic member 100C.

[0056] Prepare a rod-shaped core 100A. The core 100A will come into contact with the core 102 of the cleaning body 100.

[0057] The length of the foamed elastic member 100C is determined by the axial length of the core body 100A, the winding angle of the foamed elastic member 100C (the spiral angle θ in the cleaning body 100), and the tension applied when winding the foamed elastic member 100C.

[0058] Next, place the foamed elastic member 100C on the table with the side with the double-sided tape 100D facing upwards, and peel off one end of the release paper from the double-sided tape 100D. Then, as shown in Figure 4B, place one end of the core body 100A on the double-sided tape 100D from which the release paper has been peeled off. At this time, determine the positions of the core body 100A and the foamed elastic member 100C so that the helical angle θ in the cleaning body 100 is achieved.

[0059] Next, while peeling off the release paper of the double-sided tape 100D, rotate the core body 100A and spirally wrap the foamed elastic member 100C around the outer surface of the core body 100A (see Figure 4C), thereby arranging the foamed elastic layer 100B (foamed elastic layer 104 in the cleaning body 100) spirally on the outer surface of the core body 100A.

[0060] From the viewpoint of reducing the restoring force of the foamed elastic layer 104 in the cleaning body 100 and suppressing the peeling of the longitudinal end of the foamed elastic layer 104 from the core body 102, it is preferable to wrap the foamed elastic member 100C around the core body 100A while suppressing the degree of elastic deformation (change in the thickness of the member) of the foamed elastic member 100C. Specifically, it is desirable to control the angle at which the foamed elastic member 100C is wrapped and the tension when wrapping the foamed elastic member 100C according to the thickness of the foamed elastic member 100C.

[0061] When applying tension when wrapping the foamed elastic member 100C around the core body 100A, the tension should be such that no gap is created between the foamed elastic member 100C and the double-sided tape 100D. Specifically, a tension that extends the length of the foamed elastic member 100C by more than 100% but less than or equal to 105% is desirable. Applying too much tension makes it difficult to suppress the restorative force of the foamed elastic layer 104 in the cleaning body 100, increases the permanent elongation under tension, and tends to reduce the elastic force of the foamed elastic layer 104 necessary for cleaning.

[0062] When the foamed elastic member 100C is wrapped around the core body 100A, the foamed elastic member 100C tends to stretch. This stretch differs in the thickness direction of the foamed elastic member 100C, with the outermost edge stretching the most. This stretch is controlled by the radius of curvature at which the foamed elastic member 100C wraps around the core body 100A and the thickness of the foamed elastic member 100C. The radius of curvature at which the foamed elastic member 100C wraps around the core body 100A is controlled by the outer diameter of the core body 100A and the wrapping angle of the foamed elastic member 100C. Specifically, for example, it is desirable that the stretch is such that the outermost edge of the foamed elastic layer 104 in the cleaning body 100 is approximately 105% of the outermost edge of the foamed elastic member 100C. If it stretches too much, the elastic force of the foamed elastic layer 104 in the cleaning body 100 may decrease.

[0063] The radius of curvature at which the foamed elastic member 100C wraps around the core body 100A is preferably {(core body outer diameter / 2) + 0.2 mm} or more and {(core body outer diameter / 2) + 8.5 mm} or less, and more preferably {(core body outer diameter / 2) + 0.5 mm} or more and {(core body outer diameter / 2) + 7.0 mm} or less.

[0064] <Unit> The unit according to this embodiment comprises a cleaning body and an object to be cleaned. The object to be cleaned is a rotating member, and the cleaning body is a member that cleans the object to be cleaned while rotating in contact with the rotating object to be cleaned. The cleaning body according to this embodiment is used as the cleaning body.

[0065] The unit according to this embodiment is, for example, a cartridge-type unit that can be attached to and detached from an electrophotographic image forming apparatus. Examples of objects to be cleaned include a charged body, a transfer roll, a transfer belt, and a conveyor belt. Toner, paper dust, and other materials adhering to the surface of these objects to be cleaned are removed by the cleaning unit.

[0066] <Image forming apparatus, assembly, charging apparatus> Figure 5 is a schematic diagram showing an example of an image forming apparatus according to this embodiment. Figure 6 is a schematic diagram showing an example of an assembly according to this embodiment. Figure 7 is a schematic diagram showing an enlarged view of the peripheral portion of the charging device in Figures 5 and 6.

[0067] The image forming apparatus 10 shown in Figure 5 is a tandem and direct transfer color image forming apparatus. Inside the main body 10A of the image forming apparatus 10, there are process cartridges 18Y, 18M, 18C, and 18K for each color: yellow (Y), magenta (M), cyan (C), and black (K).

[0068] The process cartridges 18Y, 18M, 18C, and 18K are assemblies that can be attached to and detached from the image forming apparatus 10, and are examples of assemblies according to this embodiment. The process cartridges 18Y, 18M, 18C, and 18K include a photoreceptor 12, a charger 14, and a developing device 19, as shown in Figures 5 and 6, for example.

[0069] The photoreceptor 12 is driven to rotate by a motor (not shown). The surface of the photoreceptor 12 is charged by a charger 14 placed on its surface. After being charged, the photoreceptor 12 is exposed by a laser beam emitted from the exposure device 16 downstream in the direction of rotation of the photoreceptor 12, and an electrostatic charge image is formed on the photoreceptor 12. The electrostatic charge image formed on the photoreceptor 12 is developed by the developing device 19 to become a toner image. The charging, exposure, and development processes are performed on the surface of each color of photoreceptor 12, and a toner image corresponding to the respective color is formed on the surface of each color of photoreceptor 12.

[0070] The toner image formed on the photoreceptor 12 is transferred to the recording medium 24 being transported on the transport belt 20 at the point where the photoreceptor 12 and the transfer member 22 come into contact via the transport belt 20. The transfer member 22 is, for example, a roll having a conductive elastic layer on the outer surface of a conductive support, and the conductive support is rotatably supported within the image forming apparatus 10. The transport belt 20 is supported from its inner surface while tension is applied by support rolls 40 and 42, and transports the recording medium 24. The recording medium 24 is removed from the storage container 28 by the removal roller 30 and transported to the transport belt 20 by transport rolls 32 and 34.

[0071] The toner images of each color are transferred to the recording medium 24 in the order of the four process cartridges, namely, black (K), cyan (C), magenta (M), and yellow (Y).

[0072] The recording medium 24 onto which the toner image has been transferred is transported to the fuser 64, where it is heated and pressurized to fix the toner image onto the recording medium 24. Then, in the case of single-sided printing, the recording medium 24 with the fixed toner image is discharged by the discharge roll 66 onto the discharge section 68 located at the top of the image forming apparatus 10. In the case of double-sided printing, the recording medium 24 with the toner image fixed to the first side (front) is transported to the transport path 70 for double-sided printing by the reverse rotation of the discharge roll 66. Then, the recording medium 24 is transported again onto the transport belt 20 by the transport roll 72 located on the transport path 70, with the front and back sides of the recording medium 24 reversed, and the toner image is transferred from the photoreceptor 12 to the second side (back) of the recording medium 24. Finally, the recording medium 24 with the toner image transferred to the second side (back) is transported to the fuser 64, where the toner image is fixed onto the recording medium 24 by the fuser 64. Subsequently, the recording medium 24, on which the toner image has been fixed to both sides, is discharged onto the discharge section 68 by the discharge roll 66.

[0073] After the transfer of the toner image is complete, the photoreceptor 12 is cleaned by the cleaning blade 80 to remove any remaining toner or paper dust from its surface each time it rotates, preparing it for the next image formation.

[0074] The charged body 14 is a roll member having a conductive elastic layer 14B on the outer circumferential surface of a support 14A, as shown in Figure 7, for example. The support 14A is a conductive cylindrical or columnar body. The support 14A is rotatably supported within the image forming apparatus. The conductive elastic layer 14B is cylindrically laminated on the outer circumferential surface of the support 14A. The conductive elastic layer 14B is, for example, a layer in which a conductive agent is dispersed in foamed or non-foamed rubber material.

[0075] On the side of the charged body 14 opposite the photoreceptor 12, a cleaning body 100 for the charged body 14 is positioned in contact with the charged body 14. In other words, the charged body 14 and the cleaning body 100 constitute a charging device (unit) (see Figures 6 and 7). The cleaning body 100 used in this embodiment is the cleaning body used. The cleaning body 100 may be, for example, a member that is always in contact with the charged body 14 and rotates in accordance with the charged body 14, or a member that is in contact with the charged body 14 only during cleaning and rotates in accordance with the charged body 14.

[0076] The charged body 14 is pressed against the photoreceptor 12 by applying a load F to both ends of the support 14A, as shown in Figure 7, for example. As a result, the conductive elastic layer 14B elastically deforms to form a nip portion along the outer surface of the photoreceptor 12. As shown in Figure 7, for example, the cleaning body 100 is pressed against the charged body 14 by applying a load F' to both ends of the core body 102. As a result, the foamed elastic layer 104 elastically deforms to form a nip portion along the outer surface of the charged body 14.

[0077] In the configuration example shown in Figure 7, the photoreceptor 12 is driven to rotate in the direction of arrow X by a motor (not shown), and the charged body 14 rotates in the direction of arrow Y due to the rotation of the photoreceptor 12. In addition, the cleaning body 100 rotates in the direction of arrow Z due to the rotation of the charged body 14.

[0078] Although examples of the image forming apparatus and process cartridge according to this embodiment have been described above with reference to Figures 5, 6, and 7, this embodiment is not limited thereto. The image forming apparatus according to this embodiment is not limited to the tandem and direct transfer method shown in Figure 5, but can also be a well-known image forming apparatus such as an intermediate transfer method. Furthermore, the image forming apparatus according to this embodiment may not have its internal devices and components packaged in cartridges, but rather in a configuration where each component is directly arranged. A process cartridge equipped with a charging device may be a process cartridge that includes a charging device (a unit of a charged body and a cleaning body) and at least one other selected from a photoreceptor, an exposure device, a developing device, and a transfer device.

[0079] The object to be cleaned by the cleaning body according to this embodiment is not limited to an electrically charged object. Other examples of objects to be cleaned include a photoreceptor, a transfer member, a paper transport belt, a secondary transfer member in an intermediate transfer system (e.g., a secondary transfer roll), and an intermediate transfer body in an intermediate transfer system (e.g., an intermediate transfer belt). These objects to be cleaned and the cleaning body positioned in contact with them may be unitized to form a process cartridge that can be attached to and detached from an image forming apparatus.

[0080] Hereinafter, an example of an object to be cleaned by the cleaning body according to this embodiment will be described in detail, specifically an embodiment of a charged body (i.e., a charged body provided by the charging device according to this embodiment).

[0081] The charged body comprises, for example, a support and a conductive elastic layer. The conductive elastic layer may be a single layer or a laminate of multiple layers. The conductive elastic layer may be a layer whose surface is surface-treated, and a surface layer containing a polymer material may be further laminated on the outer surface of the conductive elastic layer.

[0082] Examples of materials for the support include free-cutting steel and stainless steel, and the surface may be plated. If the material does not have conductivity, a conductive treatment such as plating may be performed.

[0083] The conductive elastic layer comprises an elastic material such as rubber and a conductive agent such as carbon black or an ionic conductive agent, for example, the conductive agent being dispersed in the elastic material. The conductive elastic layer may further contain softeners, plasticizers, hardening agents, vulcanizing agents, vulcanizing aids, vulcanizing accelerators, anti-aging agents, lubricants, fillers (silica, calcium carbonate, etc.), etc. The conductive elastic layer is formed by coating the outer surface of a conductive support with a mixture of the above materials. The elastic material may be a foam, in which case the conductive elastic layer becomes a conductive foamed elastic layer.

[0084] Examples of elastic materials constituting the conductive elastic layer include silicone rubber, ethylene propylene rubber, epichlorohydrin rubber, epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber, acrylonitrile-butadiene copolymer rubber, and mixtures thereof. The elastic material may be used individually or in combination of two or more types.

[0085] Examples of conductive agents include electronic conductive agents and ionic conductive agents. Examples of electronic conductive agents include particles or powders of carbon black such as Ketjenblack and acetylene black; pyrolytic carbon and graphite; conductive metals or alloys such as aluminum, copper, nickel, and stainless steel; conductive metal oxides such as tin oxide, indium oxide, titanium oxide, tin oxide-antimony oxide solid solution, and tin oxide-indium oxide solid solution; and insulating materials whose surfaces have been treated to become conductive. Examples of ionic conductive agents include perchlorates or chlorates of onium compounds such as tetraethylammonium and lauryltrimethylammonium; perchlorates or chlorates of alkali metals or alkaline earth metals such as lithium and magnesium; and so on.

[0086] The conductive agent may be used alone or in combination of two or more types. There are no particular restrictions on the amount of conductive agent to be blended, but in the case of an electronic conductive agent, it is desirable to be in the range of 1 part by mass or more and 60 parts by mass or less per 100 parts by mass of elastic material, and in the case of an ionic conductive agent, it is desirable to be in the range of 0.1 parts by mass or more and 5.0 parts by mass or less per 100 parts by mass of elastic material.

[0087] A surface layer containing a polymer material may be provided on the surface of the charged body. Examples of polymer materials included in the surface layer include polyvinylidene fluoride, tetrafluoroethylene copolymer, polyester, polyimide, copolymerized nylon, and silicone resin. One of the above polymer materials may be used alone, or two or more may be used in combination.

[0088] The surface layer may contain a conductive material to adjust the resistance. Examples of conductive materials include carbon black, conductive metal oxide particles, and ionic conductive agents. One type of conductive material may be used alone, or two or more types may be used in combination. The surface layer may also contain insulating particles such as alumina and silica. [Examples]

[0089] The embodiments of the invention will be described in detail below with reference to examples, but the embodiments of the invention are not limited to these examples. In the following description, unless otherwise specified, "parts" and "%" are based on mass. In the following description, synthesis, processing, manufacturing, etc., were carried out at room temperature (25℃±3℃) unless otherwise specified.

[0090] <Fabrication of electrostatic rolls> A charged roll, which is an example of an embodiment of a charged material, was fabricated.

[0091] -Formation of a conductive elastic layer- • Epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber (GECHRON3106, Zeon Corporation) 100 units • Carbon black (Asahi Thermal, Asahi Carbon Co., Ltd.) 25 units • Ketjenblack EC (Lion Specialty Chemicals Co., Ltd.) Division 8 • Ionic conductive agent (lithium perchlorate) 1 part • Sulfur (200 mesh, Tsurumi Chemical Industry Co., Ltd.) 1 part • Vulcanization accelerator (Noxellar DM, Ouchi Shinko Chemical Industry Co., Ltd.) Part 2 • Vulcanization accelerator (Noxellar TT, Ouchi Shinko Chemical Industry Co., Ltd.) 0.5 parts The above materials were kneaded in an open roll to obtain an elastic layer-forming composition. The outer surface of a support made of SUS416, with a diameter of 9 mm and a total length of 370 mm, was coated with the elastic layer-forming composition to a thickness of 1.5 mm, placed in a cylindrical mold with an inner diameter of 12.0 mm, and vulcanized at 170°C for 30 minutes. After being removed from the mold, the outer surface of the conductive elastic layer was polished to obtain an elastic roll.

[0092] -Formation of the surface layer- • First resin: Polyamide resin (N-methoxymethylated nylon, F30K / Nagase ChemteX Corporation) 90 units • Second resin: Polyvinyl butyral resin (S-Rec BM-1 / Sekisui Chemical Co., Ltd.) 10 copies • Conductive agent: Carbon black (MONARCH1000 / Cabot Corporation) 13 parts • Porous polyamide filler (Orgasol2001UDNAT1 / Arkema Corporation) 10 units • Acid catalyst (NACURE4167 / King Industries) 1.0 part • Polyether-modified polydimethylsiloxane (BYK307 / BYK) 0.1 part The above materials were mixed to prepare a composition. 15 parts of the composition were diluted with 85 parts of methanol and dispersed in a bead mill. The resulting dispersion was immersed and coated onto the outer surface of the conductive elastic layer of an elastic roll, and heated at 140°C for 30 minutes to crosslink and dry. In this way, a surface layer with a thickness of 10 μm was formed, and a charged roll was obtained.

[0093] <Creating a cleaning roll> A cleaning roll for an electrostatic roller was fabricated as an example of an embodiment of a cleaning body.

[0094] [Example 1] As the core, a metal core made of SUM24EZ material with a diameter of 5.0 mm and a total length of 360 mm was prepared. As the material for the foamed elastic layer, foamed urethane (EP-70S, density 70 kg / m³) is used. 3 (Inoac Corporation) prepared it.

[0095] The polyurethane foam was thinned to the desired thickness to obtain a rectangular polyurethane foam sheet. In the vicinity of one set of sides among two sets of opposite sides of the foamed urethane sheet (the regions that become both axial ends when the cleaning roll is manufactured and correspond to the low-action regions of the foamed elastic layer), it was impregnated with an ultraviolet-curable urethane acrylate-based resin. Subsequently, the foamed urethane sheet was irradiated with ultraviolet rays to cure the ultraviolet-curable resin, and reinforcement processing of the low-action regions was performed.

[0096] On the entire one side of the foamed urethane sheet after the reinforcement processing, a double-sided tape (No. 501L, Nitto Denko Corporation) with a thickness of 0.15 mm was pasted. The foamed urethane sheet with the double-sided tape was cut out to the target length and width to obtain a strip-shaped member with the double-sided tape.

[0097] The strip-shaped member with the double-sided tape was placed on a horizontal table such that the release paper of the double-sided tape faced upward. While removing the release paper, tension was applied to the strip-shaped member with the double-sided tape so that the entire length of the strip-shaped member extended by about 0% to 5%. While rolling the metal core on the table, the strip-shaped member with the double-sided tape was wound around the metal core to obtain a cleaning roll.

[0098] [[ID=(12)]] [Comparative Example 1] A cleaning roll was manufactured in the same manner as in Example 1, except that the impregnation treatment of the ultraviolet-curable urethane acrylate-based resin at both axial ends was not performed.

[0099] [Comparative Example 2] A cleaning roll was manufactured in the same manner as in Example 1, except that the density of the foamed urethane, which is the material of the foamed elastic layer, was changed to 100 kg / m 3 and the impregnation treatment of the ultraviolet-curable urethane acrylate-based resin at both axial ends was not performed.

[0100] [Comparative Example 3] A cleaning roll was manufactured in the same manner as in Example 1, except that the density of the foamed urethane, which is the material of the foamed elastic layer, was changed to 25 kg / m 3 and the impregnation treatment of the ultraviolet-curable urethane acrylate-based resin at both axial ends was not performed.

[0101] [Example 2] The same procedure as in Example 1, except that the density of the polyurethane foam, which is the material for the foamed elastic layer, is 35 kg / m³. 3 We made the change and created a cleaning roll.

[0102] [Example 3] The same procedure as in Example 1, except that the density of the polyurethane foam, which is the material for the foamed elastic layer, is 40 kg / m³. 3 We made the change and created a cleaning roll.

[0103] [Example 4] The same procedure as in Example 1, except that the density of the polyurethane foam, which is the material for the foamed elastic layer, is 80 kg / m³. 3 We made the change and created a cleaning roll.

[0104] [Example 5] The same procedure as in Example 1, except that the density of the polyurethane foam, which is the material for the foamed elastic layer, is 90 kg / m³. 3 We made the change and created a cleaning roll.

[0105] <Fabrication of charging devices and image forming devices> A charging device was assembled by combining a charging roll with a cleaning roll from either the example or comparative example. This charging device was placed in the drum cartridge of an electrophotographic image forming apparatus, DocuCentre-V C7775 (Fujifilm Business Innovation Co., Ltd.).

[0106] Using the image forming apparatus described above, the following image formation procedures (1) and (2) were performed in an environment with a temperature of 22°C and a relative humidity of 55%. (1) 250,000 consecutive prints (250kPV) of a 50% black halftone image were printed on the entire surface of one side of an A3 size plain paper. Then, one print of a 30% black halftone image was printed on the entire surface of one side of an A3 size plain paper. (2) 500,000 black halftone images with a density of 50% were printed on the entire surface of one side of A3 size plain paper (500kPV). Then, one black halftone image with a density of 30% was printed on the entire surface of one side of A3 size plain paper. Since part of the performance evaluation test involves destroying the charged roll, multiple equivalent charging devices were manufactured and (1) and (2) were performed on them, respectively.

[0107] <Performance Evaluation> [Increase in volume resistivity] When a filming phenomenon occurs where dirt adheres to the surface of the charged roll, the volume resistivity (Ω·cm) of the charged roll increases. It is desirable that the volume resistivity of the charged roll does not fluctuate much before and after image formation. The volume resistivity (Ω·cm) of the charged roll was measured before and after image formation in each of the above (1) and (2) using the measurement method described below. A sheet-like sample (conductive elastic layer and surface layer) was taken from the central part of the charging roll from the support, and this was used as a sample for measuring volume resistivity. In accordance with JIS K6911:1995 "General Test Methods for Thermosetting Plastics," a measuring jig (R12702A / B Resistivity Chamber: Advantest) and a high-resistance meter (R8340A Digital High-Resistance / Micro-Ammeter: Advantest) were used to apply a voltage adjusted to produce an electric field (applied voltage / sample thickness) of 1000 V / cm to the sample for 30 seconds. The current value was read, and the volume resistivity was calculated using the following formula. Volume resistivity (Ω·cm) = (19.63 × applied voltage (V)) / (current (A) × sample thickness (cm)) Table 1 shows the value obtained by subtracting the volume resistivity before image formation from the volume resistivity after image formation (common logarithm).

[0108] [Image density unevenness] Image density variations caused by the filming phenomenon, where dirt adheres to the surface of the charged roll, were evaluated as follows. For both (1) and (2) above, the image density was measured at one location in the center and four locations at the edges of a 30% black halftone image using a spectrophotometer X-Rite938 (X-Rite Corporation). The difference between the maximum and minimum image density values ​​was calculated and classified as follows. The results are shown in Table 1.

[0109] A: The difference in image density is 0.2 or less. It is not visible. B: Image density difference is greater than 0.2 but less than or equal to 0.3. Within acceptable limits. C: The difference in image density is greater than 0.3. Unacceptable.

[0110] [Followability] The cleaning roll rotates in response to the rotation of the electrostatic roll. Therefore, the peripheral speed ratio = peripheral speed of the cleaning roll / peripheral speed of the electrostatic roll is 1 or less. The closer the peripheral speed ratio is to 1, the better the cleaning roll's ability to follow the rotation. The obedience of the cleaning roll to the electrostatic roll was evaluated as follows. A 5mm square visible light reflective tape was attached to the edges of both the charging roll and the cleaning roll, ensuring that it did not interfere with image formation. During the output of the last 100 sheets of the 250,000 continuous prints in (1) above, and during the output of the last 100 sheets of the 500,000 continuous prints in (2) above, the rotational speed per unit time of both the charging roll and the cleaning roll was measured using a non-contact tachometer (Tachometer 3403, HIOKI E.E. CORPORATION). The peripheral speed was calculated from the rotational speed per unit time and the outer circumference. Furthermore, the peripheral speed ratio = peripheral speed of the cleaning roll / peripheral speed of the charging roll was calculated, and the peripheral speed ratios were classified as follows. The results are shown in Table 1.

[0111] A: The peripheral speed ratio is 0.98 or higher. B: Peripheral speed ratio is less than 0.98 and 0.90 or greater. C: Peripheral speed ratio is less than 0.90.

[0112] [Table 1]

[0113] The cleaning bodies, units, charging devices, assemblies, and image forming apparatuses of this disclosure include the following embodiments:

[0114] (Note) (((1))) The core body, On the outer circumferential surface of the core, a foamed elastic layer is arranged, wound in a spiral shape from one end to the other of the core. It has an adhesive layer that bonds the core body and the foamed elastic layer, The 25% compressive load of the foamed elastic layer in the high-action region is less than or equal to half the 25% compressive load of the foamed elastic layer in the low-action region. Cleaning unit. (((2))) The cleaning body according to (((1))), wherein the 25% compressive load of the foamed elastic layer in the high-action region is 1 / 3 or less of the 25% compressive load of the foamed elastic layer in the low-action region. (((3))) The cleaning body according to (((1))) or (((2))), wherein the 25% compressive load of the foamed elastic layer in the high-action region is 0.5 kPa or more and 1.5 kPa or less. (((4))) A cleaning body according to any one of (((1))) to (((3))), wherein the 25% compressive load of the foamed elastic layer in the low-acting region is 1.5 kPa or more and 4.5 kPa or less. (((5))) The object to be cleaned and, A cleaning body described in any one of (((1))) to (((4))), comprising a cleaning body that rotates in contact with the rotating object to be cleaned and cleans the object to be cleaned, unit. (((6))) A charged body and A cleaning body described in any one of (((1))) to (((4))), comprising a cleaning body that rotates in contact with the rotating charged body and cleans the charged body, A charging device. (((7))) The charged object and, A charged body that charges the object to be charged, A cleaning body described in any one of (((1))) to (((4))) comprises a cleaning body that rotates in contact with the rotating charged body and cleans the charged body, The charged object, the charged object, and the cleaning object are assembled to be detachably attached to the main body of the device. assembly. (((8))) Photoreceptor and A charging body for charging the photoreceptor, An exposure apparatus that exposes the charged photoreceptor to form an electrostatic image, A developing apparatus for developing the electrostatic charge image formed on the photoreceptor, A cleaning body described in any one of (((1))) to (((4))), comprising a cleaning body that rotates in contact with the rotating charged body and cleans the charged body, Image forming apparatus.

[0115] According to (((1))), compared to a cleaning body where there is no difference between the 25% compressive load of the foamed elastic layer in the high-action region and the 25% compressive load of the foamed elastic layer in the low-action region, a cleaning body is provided in which dirt is less likely to adhere to the surface of the object to be cleaned, and in which the ability to adhere to the object to be cleaned is maintained for a long period of time. According to (((2))), compared to a cleaning body in which the 25% compressive load of the foamed elastic layer in the high-action region is more than 1 / 3 of the 25% compressive load of the foamed elastic layer in the low-action region, a cleaning body is provided in which dirt is less likely to adhere to the surface of the object to be cleaned, and in which the ability to follow the object to be cleaned is maintained for a long period of time. According to (((3))), compared to a cleaning body in which the 25% compressive load of the foamed elastic layer in the high-action region is less than 0.5 kPa or greater than 1.5 kPa, a cleaning body is provided in which dirt is less likely to adhere to the surface of the object to be cleaned, and in which the ability to follow the object to be cleaned is maintained for a long period of time. According to (((4))), compared to cleaning bodies in which the 25% compressive load of the foamed elastic layer in the low-acting region is less than 1.5 kPa or greater than 4.5 kPa, a cleaning body is provided in which dirt is less likely to adhere to the surface of the object to be cleaned, and in which the ability to follow the object to be cleaned is maintained for a long period of time. According to (((5))), compared to a unit having a cleaning body in which there is no difference between the 25% compressive load of the foamed elastic layer in the high-action region and the 25% compressive load of the foamed elastic layer in the low-action region, a unit is provided in which dirt is less likely to adhere to the surface of the object to be cleaned, and in which the obedience of the cleaning body to the object to be cleaned is maintained for a long period of time. According to (((6))), compared to a charging device having a cleaning body where there is no difference between the 25% compressive load of the foamed elastic layer in the high-action region and the 25% compressive load of the foamed elastic layer in the low-action region, a charging device is provided in which dirt is less likely to adhere to the surface of the charging body and the dependence of the cleaning body on the charging body is maintained for a long period of time. According to (((7))), compared to an assembly having a cleaning body in which there is no difference between the 25% compressive load of the foamed elastic layer in the high-action region and the 25% compressive load of the foamed elastic layer in the low-action region, an assembly is provided in which dirt is less likely to adhere to the surface of the charged body and in which the dependence of the cleaning body on the charged body is maintained for a long period of time. According to (((8))), compared to an image forming apparatus having a cleaning body in which there is no difference between the 25% compressive load of the foamed elastic layer in the high-action region and the 25% compressive load of the foamed elastic layer in the low-action region, an image forming apparatus is provided in which dirt is less likely to adhere to the surface of the charged body and the obedience of the cleaning body to the charged body is maintained for a long period of time. [Explanation of Symbols]

[0116] 100 Cleaning body, 102 Core body, 104 Foamed elastic layer, 106 Adhesive layer

[0117] 100A Core, 100B Foamed elastic layer, 100C Foamed elastic component, 100D Double-sided tape

[0118] 10 Image forming apparatus, 10A Apparatus body, 12 Photoreceptor, 14 Charged body, 14A Support, 14B Conductive elastic layer, 16 Exposure apparatus, 19 Developing apparatus, 20 Conveyor belt, 22 Transfer member, 24 Recording medium, 64 Fixing apparatus, 66 Discharge roll, 68 Discharge section, 70 Conveyor path, 72 Conveyor roll, 80 Cleaning blade

Claims

1. The core body, On the outer circumferential surface of the core, a foamed elastic layer is arranged, wound in a spiral shape from one end to the other of the core. It has an adhesive layer that bonds the core body and the foamed elastic layer, The 25% compressive load of the foamed elastic layer in the high-action region is 1 / 2 or less of the 25% compressive load of the foamed elastic layer in the low-action region. Cleaning unit.

2. The cleaning body according to claim 1, wherein the 25% compressive load of the foamed elastic layer in the high-action region is 1 / 3 or less of the 25% compressive load of the foamed elastic layer in the low-action region.

3. The cleaning body according to claim 1, wherein the 25% compressive load of the foamed elastic layer in the high-action region is 0.5 kPa or more and 1.5 kPa or less.

4. The cleaning body according to claim 1, wherein the 25% compressive load of the foamed elastic layer in the low-acting region is 1.5 kPa or more and 4.5 kPa or less.

5. The object to be cleaned and, A cleaning body according to any one of claims 1 to 4, comprising a cleaning body that rotates in contact with the rotating object to be cleaned and cleans the object to be cleaned, unit.

6. A charged body and A cleaning body according to any one of claims 1 to 4, comprising a cleaning body that rotates in contact with the rotating charged body and cleans the charged body, A charging device.

7. The charged object and, A charged body that charges the object to be charged, A cleaning body according to any one of claims 1 to 4, comprising a cleaning body that rotates in contact with the rotating charged body and cleans the charged body, The charged object, the charged object, and the cleaning object are assembled to be detachably attached to the main body of the device. assembly.

8. Photoreceptor and A charging body for charging the photoreceptor, An exposure apparatus that exposes the charged photoreceptor to form an electrostatic image, A developing apparatus for developing the electrostatic charge image formed on the photoreceptor, A cleaning body according to any one of claims 1 to 4, comprising a cleaning body that rotates in contact with the rotating charged body and cleans the charged body, Image forming apparatus.

Images