Image forming system

Abstract

To suppress color variation in an image transferred onto an intermediate transfer body, compared with a configuration in which a surface forming member is disposed to stabilize surface formation of the intermediate transfer body so that the pressure of a transfer portion formed by an image bearing member and a transfer member via the intermediate transfer body becomes equal between the transfer portion located on the uppermost stream and the transfer portion located on the lowermost stream in the rotation direction of the intermediate transfer body.SOLUTION: An image forming system comprises a plurality of image bearing members, an intermediate transfer body, a plurality of transfer members, a first surface forming member disposed upstream of the plurality of image bearing members in the rotation direction of the intermediate transfer body, and a second surface forming member disposed downstream of the plurality of image bearing members in the rotation direction and stabilizing surface formation of the intermediate transfer body together with the first surface forming member. The first surface forming member and the second surface forming member are arranged such that the pressure of a transfer portion formed by the image bearing member and the transfer member via the intermediate transfer body becomes higher at the transfer portion located on the lowermost stream in comparison to the transfer portion located on the uppermost stream in the rotation direction.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to imaging systems. [Background technology]

[0002] Patent Document 1 discloses an image forming apparatus having an image carrier that carries a developer image, a belt for transferring the developer image on the image carrier, and a transfer member that contacts the back surface of the belt, wherein the image carrier contacts the surface of the belt, and wherein, in the contact area between the image carrier and the belt in the direction of movement of the belt, the belt and the transfer member are in contact in the area downstream in the direction of movement of the belt, and are not in contact with each other in the area upstream in the direction of movement of the belt. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-18177 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure aims to suppress color variation in the image transferred to the intermediate transfer body compared to a configuration in which a surface forming member is arranged to stabilize the surface formation of the intermediate transfer body so that the pressure of the transfer section formed by the image carrier and the transfer member via the intermediate transfer body is the same between the transfer section located most upstream and the transfer section located most downstream in the rotation direction of the intermediate transfer body. [Means for solving the problem]

[0005] A first aspect of the present disclosure is an image forming system comprising: a plurality of image carriers that carry images; an intermediate transfer member that rotates and onto which images formed on the plurality of image carriers are transferred; a plurality of transfer members that transfer the images formed on the plurality of image carriers to the intermediate transfer member; a first surface forming member that is arranged upstream of the plurality of image carriers in the direction of rotation of the intermediate transfer member; and a second surface forming member that is arranged downstream of the plurality of image carriers in the direction of rotation and that, together with the first surface forming member, stabilizes the surface formation of the intermediate transfer member, wherein the first surface forming member and the second surface forming member are arranged so that the pressure of the transfer section formed by the image carriers and the transfer members via the intermediate transfer members is higher at the transfer section located furthest downstream in the direction of rotation than at the transfer section located furthest upstream.

[0006] A second aspect of the present disclosure is an image forming system in which, in the image forming system of the first aspect, the first surface forming member and the second surface forming member are arranged so that the tangent surfaces tangent to the vertices of the first surface forming member and the second surface forming member are inclined with respect to a virtual plane tangent to the vertex of the image carrier.

[0007] A third aspect of the present disclosure is an image forming system in which, in the image forming system of the second aspect, the contact portion of the first surface forming member with the intermediate transfer body is arranged on the transfer member side of the virtual surface.

[0008] A fourth aspect of the present disclosure is the image forming system of the third aspect, further comprising a first moving mechanism that moves the first surface forming member toward the transfer member with respect to the virtual surface.

[0009] A fifth aspect of the present disclosure is an image forming system according to the second aspect, further comprising a suppression mechanism that is disposed downstream of the second surface forming member in the rotation direction and that suppresses skewing of the intermediate transfer body, and the contact portion of the second surface forming member with the intermediate transfer body is disposed on the opposite side of the virtual plane from the transfer member side.

[0010] A sixth aspect of the present disclosure is the image forming system of the fifth aspect, further comprising a second movement mechanism that moves the second surface forming member to the opposite side of the transfer member with respect to the virtual surface.

[0011] A seventh aspect of the present disclosure is an image forming system in which, in the image forming system of the first aspect, the first surface forming member and the second surface forming member are arranged so that the pressure at the transfer section is higher at the transfer section located downstream in the rotation direction than at the transfer section located upstream.

[0012] An eighth aspect of the present disclosure is an image forming system according to the first aspect, wherein the nip width between the image carrier located at the most downstream position in the rotation direction and the intermediate transfer member is wider than the nip width between the image carrier located at the most upstream position and the intermediate transfer member, and the nip width between the transfer member located at the most downstream position in the rotation direction and the intermediate transfer member is narrower than the nip width between the transfer member located at the most upstream position and the intermediate transfer member.

[0013] A ninth aspect of the present disclosure is an image forming system according to the eighth aspect, wherein, among the image carriers adjacent to each other in the rotation direction, the nip width between the image carrier located downstream and the intermediate transfer member is wider than the nip width between the image carrier located upstream and the intermediate transfer member, and among the transfer members adjacent to each other in the rotation direction, the nip width between the transfer member located downstream and the intermediate transfer member is narrower than the nip width between the transfer member located upstream and the intermediate transfer member.

[0014] A tenth aspect of the present disclosure is an image forming system according to the second aspect, further comprising a first moving mechanism that moves the first surface forming member toward the transfer member relative to the virtual surface, a second moving mechanism that moves the second surface forming member to the opposite side of the transfer member relative to the virtual surface, and a processor that controls the operation of each of the first moving mechanism and the second moving mechanism, wherein the processor determines the positions of the first surface forming member and the second surface forming member relative to the virtual surface based on information regarding the particle size of the toner that forms the image, and operates the first moving mechanism and the second moving mechanism to move the first surface forming member and the second surface forming member to the determined positions, respectively.

[0015] An eleventh aspect of the present disclosure is an image forming system in which, in the image forming system of the tenth aspect, the processor increases the distance between the first surface forming member and the second surface forming member in the direction perpendicular to the virtual plane depending on the particle size of the toner.

[0016] A twelfth aspect of the present disclosure is an image forming system of the second aspect, further comprising a first moving mechanism that moves the first surface forming member toward the transfer member relative to the virtual surface, a second moving mechanism that moves the second surface forming member to the opposite side of the transfer member relative to the virtual surface, and a processor that controls the operation of each of the first moving mechanism and the second moving mechanism, wherein the processor determines the positions of the first surface forming member and the second surface forming member relative to the virtual surface based on information regarding the thickness of the recording medium to which the image is transferred, and operates the first moving mechanism and the second moving mechanism to move the first surface forming member and the second surface forming member to the determined positions, respectively.

[0017] A thirteenth aspect of the present disclosure is an image forming system in which, in the image forming system of the twelfth aspect, the processor increases the distance between the first surface forming member and the second surface forming member in the direction perpendicular to the virtual plane depending on the thickness of the recording medium.

[0018] A fourteenth aspect of the present disclosure is an image forming system of the second aspect, further comprising a first moving mechanism that moves the first surface forming member toward the transfer member relative to the virtual surface, a second moving mechanism that moves the second surface forming member to the opposite side of the transfer member relative to the virtual surface, and a processor that controls the operation of each of the first moving mechanism and the second moving mechanism, wherein the processor determines the positions of the first surface forming member and the second surface forming member relative to the virtual surface based on information regarding the unevenness of the recording medium to which the image is transferred, and operates the first moving mechanism and the second moving mechanism to move the first surface forming member and the second surface forming member to the determined positions, respectively.

[0019] A fifteenth aspect of the present disclosure is an image forming system in which, in the image forming system of the fourteenth aspect, the processor increases the distance between the first surface forming member and the second surface forming member in the direction perpendicular to the virtual surface depending on the size of the unevenness of the recording medium. [Effects of the Invention]

[0020] In the image forming system of the first embodiment, color variation of the image transferred to the intermediate transfer body can be suppressed compared to a configuration in which a surface forming member is arranged to stabilize the surface formation of the intermediate transfer body so that the pressure of the transfer section formed by the image carrier and the transfer member via the intermediate transfer body is the same between the transfer section located most upstream and the transfer section located most downstream in the rotation direction of the intermediate transfer body.

[0021] In the image forming system of the second embodiment, color variation of the image transferred to the intermediate transfer body can be suppressed compared to a configuration in which the first surface forming member and the second surface forming member are arranged so that the tangent surface and the virtual surface are parallel.

[0022] In the image forming system of the third embodiment, color variation of the image transferred to the intermediate transfer body can be suppressed compared to a configuration in which the contact portion of the first surface forming member with the intermediate transfer body is positioned closer to the transfer member than the virtual surface.

[0023] In the fourth embodiment of the image forming system, color variation in the image transferred to the intermediate transfer body can be suppressed regardless of the image forming conditions, compared to a configuration in which the positional relationship of the first surface forming member with respect to the virtual surface is fixed.

[0024] In the image forming system of the fifth embodiment, color variation in the image transferred to the intermediate transfer body can be suppressed compared to a configuration in which the contact portion of the second surface forming member with the intermediate transfer body is positioned closer to the transfer member than the virtual surface.

[0025] In the sixth embodiment of the image forming system, color variation in the image transferred to the intermediate transfer body can be suppressed regardless of the image forming conditions, compared to a configuration in which the positional relationship of the second surface forming member with respect to the virtual surface is fixed.

[0026] In the seventh embodiment of the image forming system, color variation in the image transferred to the intermediate transfer body can be suppressed compared to a configuration in which the surface forming member is arranged so that the pressure at the transfer section is the same at the transfer section located most upstream and the transfer section located most downstream in the rotation direction of the intermediate transfer body.

[0027] In the image forming system of the eighth embodiment, the nip width between the image carrier located at the most downstream position and the intermediate transfer member in the rotation direction of the intermediate transfer member is the same as the nip width between the image carrier located at the most upstream position and the intermediate transfer member, and the nip width between the transfer member located at the most downstream position and the intermediate transfer member is the same as the nip width between the transfer member located at the most upstream position and the intermediate transfer member, and color variation in the image transferred to the intermediate transfer member can be suppressed compared to a configuration in which the nip width between the image carrier located at the most downstream position and the intermediate transfer member is the same as the nip width between the transfer member located at the most upstream position and the intermediate transfer member.

[0028] In the image forming system of the ninth aspect, it is possible to prevent the image from being transferred back to the most downstream image carrier due to the pressure pressing the intermediate transfer body against the most downstream image carrier.

[0029] In the image forming system of the 10th embodiment, color variation of the image transferred to the intermediate transfer body can be suppressed compared to a configuration in which the positions of the first surface forming member and the second surface forming member are fixed regardless of the particle size of the toner.

[0030] In the image forming system of the 11th embodiment, color variation in the image transferred to the intermediate transfer body can be suppressed compared to a configuration in which the distance perpendicular to the virtual plane between the first surface forming member and the second surface forming member is constant regardless of the particle size of the toner.

[0031] In the image forming system of the 12th embodiment, color variation of the image transferred to the intermediate transfer body can be suppressed compared to a configuration in which the positions of the first surface forming member and the second surface forming member are fixed regardless of the thickness of the recording medium.

[0032] In the image forming system of the thirteenth aspect, color variation in the image transferred to the intermediate transfer body can be suppressed compared to a configuration in which the distance perpendicular to the virtual plane between the first surface forming member and the second surface forming member is constant regardless of the thickness of the recording medium.

[0033] In the image forming system of the 14th embodiment, color variation in the image transferred to the intermediate transfer body can be suppressed compared to a configuration in which the positions of the first surface forming member and the second surface forming member are fixed regardless of the unevenness of the recording medium.

[0034] In the image forming system of the 15th embodiment, color variation in the image transferred to the intermediate transfer body can be suppressed compared to a configuration in which the distance perpendicular to the virtual plane between the first surface forming member and the second surface forming member is constant regardless of the size of the unevenness of the recording medium. [Brief explanation of the drawings]

[0035] [Figure 1] 1 is a schematic diagram illustrating an image forming apparatus according to an embodiment of the present disclosure. [Figure 2] 1 is a block diagram showing a hardware configuration of an image forming apparatus according to an embodiment of the present disclosure. [Figure 3] FIG. 2 is a schematic diagram illustrating a relationship between a virtual surface and a contact surface of an image forming apparatus according to an embodiment of the present disclosure. [Figure 4] 2 is an enlarged view of the periphery of a first surface forming member of the image forming apparatus shown in FIG. [Figure 5]2 is an enlarged view of the periphery of a second surface forming member of the image forming apparatus shown in FIG. 1. [Figure 6] 2 is an enlarged view of a transfer portion (nip portion) located at the most downstream side of the image forming apparatus shown in FIG. [Figure 7] 2 is an enlarged view of a transfer portion (nip portion) located at the most upstream side of the image forming apparatus shown in FIG. [Figure 8] 10 is a flowchart for explaining an operation when adjusting the positions of a first surface forming member and a second surface forming member of an image forming apparatus according to an embodiment of the present disclosure. [Figure 9] 10 is a graph showing an improvement in the primary transfer rate when an image forming apparatus according to an embodiment of the present disclosure is used. [Figure 10] 10 is a graph showing an improvement in the toner charge amount when an image forming apparatus according to an embodiment of the present disclosure is used. [Figure 11] 10 is a graph showing the position of a second surface forming member relative to a virtual surface of an image forming apparatus according to an embodiment of the present disclosure and the improvement status of the primary transfer rate in the Δ axis direction. [Figure 12] 10 is a graph showing the relationship between toner particle size and nip pressure in a primary transfer roll when an image forming apparatus according to an embodiment of the present disclosure is used. [Figure 13] 10 is a graph showing the relationship between the type of paper or the thickness of paper and the nip pressure in the primary transfer roll when an image forming apparatus according to an embodiment of the present disclosure is used. [Figure 14] 10 is a flowchart illustrating an operation when adjusting the positions of a first surface forming member and a second surface forming member of an image forming apparatus according to another embodiment of the present disclosure. [Figure 15] 10 is a flowchart illustrating an operation when adjusting the positions of a first surface forming member and a second surface forming member of an image forming apparatus according to another embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0036] An image forming apparatus 20 as an example of an image forming system according to an embodiment of the present disclosure will be described with reference to FIGS.

[0037] Arrow H shown in each figure indicates the up-down direction of image forming apparatus 20 (specifically, the vertical direction). Arrow W indicates the width direction of image forming apparatus 20 (specifically, the horizontal direction). Arrow D indicates the depth direction of image forming apparatus 20 (specifically, the horizontal direction). The up-down direction, width direction, and depth direction of image forming apparatus 20 intersect with each other (specifically, perpendicular to each other). Note that the present disclosure is not limited to this configuration, and the width direction may be the depth direction of the apparatus, and the depth direction may be the width direction of the apparatus.

[0038] Furthermore, components indicated by the same reference numerals in each drawing are the same or similar components. Note that duplicated explanations and reference numerals may be omitted in the embodiments described below. Furthermore, all drawings used in the following description are schematic, and the dimensional relationships, ratios, etc. of the elements shown in the drawings do not necessarily match those in reality. Furthermore, the dimensional relationships, ratios, etc. of the elements do not necessarily match between multiple drawings.

[0039] 1, the image forming apparatus 20 according to this embodiment is an apparatus that forms an image on a recording medium P. Specifically, the image forming apparatus 20 is an electrophotographic image forming apparatus that forms a toner image (an example of an image) on the recording medium P. Note that, in this embodiment, paper is used as an example of the recording medium P, but the present invention is not limited to this.

[0040] The image forming apparatus 20 includes an image forming section 22 and a fixing section 24. Each section of the image forming apparatus 20 (the image forming section 22 and the fixing section 24) will be described below.

[0041] (Image forming unit 22) 1, the image forming section 22 has a function of forming a toner image (also referred to as a toner image) on a recording medium P. Specifically, the image forming section 22 has a plurality of image forming units 30 and a transfer section 40.

[0042] The multiple image forming units 30 are provided on a surface 42A of a transfer belt 42 (described later) at intervals in the rotation direction A of the transfer belt 42. The multiple image forming units 30 form toner images of different colors on the surface 42A of the transfer belt 42. The image forming units 30 are arranged in the order of V (spot color), Y (yellow), M (magenta), C (cyan), and K (black) from upstream in the rotation direction A.

[0043] As shown in Fig. 1, each image forming unit 30 is configured similarly except for the toner used. For this reason, in Fig. 1, the components of image forming unit 30(V) are assigned reference numerals to represent each image forming unit 30.

[0044] Each image forming unit 30 includes a photosensitive drum 32 as an example of an image carrier that has the function of holding a toner image (image). The photosensitive drum 32 rotates in one direction (for example, the clockwise direction in FIG. 1).

[0045] Furthermore, each image forming unit 30 has a charger 34 , an exposure device 36 , and a developing device 38 .

[0046] In each image forming unit 30, a charger 34 charges a photosensitive drum 32. An exposure device 36 exposes the photosensitive drum 32 charged by the charger 34 to light to form an electrostatic latent image on the photosensitive drum 32. A developing device 38 develops the electrostatic latent image formed on the photosensitive drum 32 by the exposure device 36 to form a toner image.

[0047] The photosensitive drum 32 rotates while holding the electrostatic latent image formed as described above on its outer periphery, and the electrostatic latent image is transported to the developing device 38 .

[0048] 1, the transfer unit 40 has a function of transferring the toner image formed by the image forming unit 30 onto a recording medium P. Specifically, the transfer unit 40 performs primary transfer of the toner image on each photosensitive drum 32 onto a transfer belt 42, which is an example of an intermediate transfer body, and then performs secondary transfer of the superposed toner image onto the recording medium P. Specifically, as shown in FIG. 1, the transfer unit 40 includes the transfer belt 42, a primary transfer roll 44, and a secondary transfer roll 46.

[0049] The primary transfer roll 44 is a roll that transfers the toner image on each photosensitive drum 32 to the transfer belt 42 at a nip portion N1 between the photosensitive drum 32 and the primary transfer roll 44. In this embodiment, a primary transfer electric field is applied between the primary transfer roll 44 and the photosensitive drum 32, so that the toner image formed on the photosensitive drum 32 is transferred to the transfer belt 42 at the nip portion N1. The primary transfer roll 44 is an example of a transfer member.

[0050] The toner images are transferred from each photosensitive drum 32 to a surface 42A, which serves as the outer peripheral surface, of the transfer belt 42. As shown in Fig. 1, the transfer belt 42 is an endless band having a circular shape, and its position is determined by being wound around a plurality of rolls 48.

[0051] The transfer belt 42 rotates in the direction of arrow A when, for example, a drive roll 48D among the multiple rolls 48 is rotationally driven by a driving force from a drive source (not shown). Among the multiple rolls 48, roll 48S shown in FIG. 1 is a steering roll 48S as an example of a suppression mechanism that suppresses skew of the transfer belt 42 (movement in the width direction of the transfer belt 42, in other words, movement in the axial direction of the roll 48). This steering roll 48S is located downstream in the rotation direction A from a second-surface forming roll 70, which will be described later. Among the multiple rolls 48, roll 48B shown in FIG. 1 is an opposing roll 48B that faces the secondary transfer roll 46.

[0052] The secondary transfer roll 46 is a roll that transfers the toner image transferred to the transfer belt 42 to the recording medium P at the nip portion N2 between the opposing roll 48B and the secondary transfer roll 46. In this embodiment, a secondary transfer electric field is applied between the opposing roll 48B and the secondary transfer roll 46, so that the toner image transferred to the transfer belt 42 is transferred to the recording medium P at the nip portion N2.

[0053] 1, the transfer unit 40 includes a first-surface forming roll 60 and a second-surface forming roll 70. The first-surface forming roll 60 is an example of a first-surface forming member. The second-surface forming roll 70 is an example of a second-surface forming member.

[0054] The first-surface forming roll 60 is disposed upstream of each image forming unit 30 in the rotation direction A. Specifically, as shown in Fig. 4, the first-surface forming roll 60 is disposed between the image forming unit 30(V) located at the most upstream position in the rotation direction A among the image forming units 30 and the drive roll 48D.

[0055] The second-side forming roll 70 is disposed downstream of each image forming unit 30 in the rotation direction A. Specifically, as shown in Fig. 5, the second-side forming roll 70 is disposed between the image forming unit 30(K) located at the most downstream position in the rotation direction A among the image forming units 30 and the steering roll 48S.

[0056] The first surface forming roll 60 and the second surface forming roll 70 have the function of supporting the transfer belt 42 from the inner surface side and stabilizing the surface formation of the transfer belt 42 .

[0057] The first surface forming roll 60 and the second surface forming roll 70 are arranged so that the pressure of the nip portion N1, which serves as a transfer portion formed by the photosensitive drum 32 and the primary transfer roll 44 via the transfer belt 42, is higher at the nip portion N1 located at the most downstream side in the circumferential direction A than at the nip portion N1 located at the most upstream side.

[0058] Specifically, as shown in FIGS. 3 to 5 , the first-surface forming roll 60 and the second-surface forming roll 70 are disposed so that contact surfaces TP2 contacting the vertices 60P and 70P, respectively, are inclined with respect to an imaginary plane TP1 contacting the vertex 32P of the photosensitive drum 32. The vertex 60P of the first-surface forming roll 60 is the vertex opposite the primary transfer roll 44, and in this embodiment, is the upper vertex in the vertical direction of the device. The vertex 70P of the second-surface forming roll 70 is the vertex opposite the primary transfer roll 44, and in this embodiment, is the upper vertex in the vertical direction of the device. The vertex 32P of the photosensitive drum 32 is the vertex on the primary transfer roll 44 side, and is the lower vertex in the vertical direction of the device.

[0059] More specifically, the contact portion of the first-surface forming roll 60 with the transfer belt 42 is located closer to the primary transfer roll 44 than the virtual plane TP1 (see FIG. 4). The contact portion of the second-surface forming roll 70 with the transfer belt 42 is located on the opposite side of the virtual plane TP1 from the primary transfer roll 44 (see FIG. 5).

[0060] In this embodiment, as described above, the first surface forming roll 60 and the second surface forming roll 70 are arranged so that the pressure at the nip portion N1 is higher at the nip portion N1 located downstream in the circumferential direction A than at the nip portion N1 located upstream, but the present disclosure is not limited to this configuration.

[0061] As shown in FIGS. 4 and 5, the transfer unit 40 includes a first moving mechanism 62 and a second moving mechanism 72.

[0062] The first movement mechanism 62 has a function of moving the first surface forming roll 60 toward the primary transfer roll 44 with respect to the imaginary plane TP1. As the first movement mechanism 62, for example, a ball screw mechanism, a cam mechanism, a rack and pinion mechanism, a belt and pulley mechanism, a sprocket and chain mechanism, a gear mechanism, or the like, using an electric motor, an electric actuator, or the like as a drive source may be used.

[0063] As an example, the first moving mechanism 62 of the present embodiment includes a main body 64 that is directly or indirectly attached to the main body of the image forming apparatus 20, and a moving part 66 that moves relative to the main body 64. More specifically, as shown in Fig. 4, the first moving mechanism 62 has the main body 64 that is fixed directly or indirectly to the main body of the image forming apparatus 20, and the moving part 66 that moves in the vertical direction of the apparatus relative to the main body 64.

[0064] A drive source (not shown) is provided inside the main body 64 for moving the moving unit 66 relative to the main body 64. The drive source of the main body 64 is controlled by a processor 100, which will be described later. As a result, the amount of movement of the moving unit 66 relative to the main body 64 is controlled by the processor 100.

[0065] A pair of bearings 68 that rotatably support the first-surface forming roll 60 are provided at the tip of the moving portion 66 .

[0066] The second movement mechanism 72 has a function of moving the second surface forming roll 70 to the opposite side of the virtual plane TP1 from the primary transfer roll 44. As the second movement mechanism 72, for example, a ball screw mechanism, a cam mechanism, a rack and pinion mechanism, a belt and pulley mechanism, a sprocket and chain mechanism, a gear mechanism, or the like, using an electric motor, an electric actuator, or the like as a drive source may be used.

[0067] As an example, the second movement mechanism 72 of the present embodiment includes a main body 74 that is directly or indirectly attached to the main body of the image forming apparatus 20, and a movement unit 76 that moves relative to the main body 74. More specifically, as shown in Fig. 5 , the second movement mechanism 72 has the main body 74 that is fixed directly or indirectly to the main body of the image forming apparatus 20, and the movement unit 76 that moves in the vertical direction of the apparatus relative to the main body 74.

[0068] A drive source (not shown) is provided inside the main body 74 for moving the moving unit 76 relative to the main body 74. The drive source of the main body 74 is controlled by a processor 100, which will be described later. As a result, the amount of movement of the moving unit 66 relative to the main body 74 is controlled by the processor 100.

[0069] A pair of bearings 78 that rotatably support the second surface forming roll 70 are provided at the tip of the moving portion 76 .

[0070] The inclination of the contact surface TP2 with respect to the imaginary plane TP1 changes when the positions of the first-surface forming roll 60 and the second-surface forming roll 70 with respect to the imaginary plane TP1 are adjusted by the first moving mechanism 62 and the second moving mechanism 72. The contact pressure of the transfer belt 42 with respect to the photosensitive drum 32 changes when the inclination of the contact surface TP2 with respect to the imaginary plane TP1 changes. In other words, the contact pressure of the transfer belt 42 with respect to the photosensitive drum 32 can be adjusted by adjusting the inclination of the contact surface TP2 with respect to the imaginary plane TP1.

[0071] 3, in this embodiment, the contact portion of the first-side forming roll 60 with the transfer belt 42 is located above the imaginary plane TP1 in the vertical direction of the device, and the contact portion of the second-side forming roll 70 with the transfer belt 42 is located below the imaginary plane TP1 in the vertical direction of the device. Therefore, the contact surface TP2 is inclined from the lower right to the upper left in the rotation direction A as viewed in FIG.

[0072] In this embodiment, since the contact surface TP2 is inclined with respect to the imaginary plane TP1 as described above, as shown in FIGS. 6 and 7 , the nip width W1 between the photosensitive drum 32 located at the most downstream position and the transfer belt 42 in the rotation direction A is wider than the nip width W1 between the photosensitive drum 32 located at the most upstream position and the transfer belt 42. Specifically, the nip width W1(K) is wider than the nip width W1(V). Furthermore, the nip width W2 between the primary transfer roll 44 located at the most downstream position and the transfer belt 42 in the rotation direction A is narrower than the nip width W2 between the primary transfer roll 44 located at the most upstream position and the transfer belt 42. Specifically, the nip width W2(K) is narrower than the nip width W2(V).

[0073] In this embodiment, among the photosensitive drums 32 adjacent to each other in the rotation direction A, the nip width W1 between the downstream photosensitive drum 32 and the transfer belt 42 may be wider than the nip width W1 between the upstream photosensitive drum 32 and the transfer belt 42. For example, the nip width W1(K) may be wider than the nip width W1(C). Furthermore, among the primary transfer rolls 44 adjacent to each other in the rotation direction A, the nip width W2 between the downstream primary transfer roll 44 and the transfer belt 42 may be narrower than the nip width W2 between the upstream primary transfer roll 44 and the transfer belt 42. For example, the nip width W2(Y) may be narrower than the nip width W2(V).

[0074] (Fixing unit 24) 1, the fixing unit 24 has a function of fixing the toner image transferred to the recording medium P by the secondary transfer roll 46 to the recording medium P. Specifically, the fixing unit 24 has a heating roll 24A as a heating member and a pressure roll 24B as a pressure member. In the fixing unit 24, the toner image formed on the recording medium P is fixed to the recording medium P by heating and pressurizing the recording medium P with the heating roll 24A and the pressure roll 24B.

[0075] As shown in FIG. 2, the image forming apparatus 20 further includes a processor 100, a storage unit 102, an operation unit 104, a display unit 106, a communication unit 108, and the like.

[0076] (Processor 100) The processor 100 includes a CPU (Central Processing Unit) 100A, a ROM (Read Only Memory) 100B, a RAM (Random Access Memory) 100C, and an input / output interface (I / O) 100D. The processor 100 controls the overall operation of the image forming apparatus 20. For example, various control programs and various parameters are stored in advance in the ROM 100B. The RAM 100C is used as a work area when the CPU 100A executes various programs.

[0077] The storage unit 102 stores various programs and data for executing print processing, application programs, and the like.

[0078] The operation unit 104 is used to input various types of information.

[0079] The display unit 106 is used to display various types of information.

[0080] The communication unit 108 is an interface for transmitting and receiving various data to and from an external device such as a server, etc. The communication unit 108 may be configured to be capable of directly communicating with each device using short-range wireless communication such as Wi-Fi (registered trademark) or Bluetooth (registered trademark).

[0081] The image reading unit 26 has a function of reading an image of a document set in the image forming apparatus 20. The image forming apparatus 20 of the present embodiment includes the image reading unit 26 as an example, but the present disclosure is not limited to this configuration, and the image reading unit 26 may not be included.

[0082] As shown in FIG. 2, the components of the image forming apparatus 20 are electrically connected to one another via a system bus.

[0083] Next, the control of the operations of the first moving mechanism 62 and the second moving mechanism 72 by the processor 100 of this embodiment will be described.

[0084] The processor 100 may determine the positions of the first surface forming roll 60 and the second surface forming roll 70 relative to the virtual plane TP1 based on information regarding the particle size of the toner that forms the image, and operate the first moving mechanism 62 and the second moving mechanism 72 to move the first surface forming roll 60 and the second surface forming roll 70 to the determined positions, respectively.

[0085] Specifically, first, processor 100 acquires information about the particle size of toner that forms an image. As an example, the information about the particle size of toner is read from ROM 100B, RAM 100C, or storage unit 102. Note that the information about the particle size of toner may also be acquired from a network or the like via communication unit 108.

[0086] Next, the processor 100 determines the positions of the first-surface forming roll 60 and the second-surface forming roll 70 relative to the virtual plane TP1 based on the information about the particle size of the toner. Specifically, the information about the particle size of the toner is linked to the positions of the first-surface forming roll 60 and the second-surface forming roll 70 relative to the virtual plane TP1, and the processor 100 obtains the linked position information of the first-surface forming roll 60 and the second-surface forming roll 70 based on the information about the particle size of the toner.

[0087] In this embodiment, as an example, the processor 100 increases the distance L between the first-side forming roll 60 and the second-side forming roll 70 in the direction perpendicular to the imaginary plane TP1 in accordance with the particle size of the toner. Specifically, the processor 100 increases the distance L between the first-side forming roll 60 and the second-side forming roll 70 in the vertical direction of the device. In other words, the larger the particle size of the toner, the more the processor 100 inclines the contact plane TP2 with respect to the imaginary plane TP1.

[0088] Next, the operation of adjusting the positions of the first-side forming roll 60 and the second-side forming roll 70 of the image forming apparatus 20 of this embodiment will be described with reference to the flowchart shown in FIG.

[0089] First, the processor 100 obtains information about the particle size of the toner that forms the image (step S200).

[0090] Next, the processor 100 determines the positions of the first-side forming roll 60 and the second-side forming roll 70 relative to the virtual plane TP1 based on the information about the particle size of the toner (step S202).

[0091] Then, the processor 100 operates the first movement mechanism 62 and the second movement mechanism 72 so that the first surface forming roll 60 and the second surface forming roll 70 move to the positions determined in step S202 (step S204).

[0092] When the first-side forming roll 60 and the second-side forming roll 70 move to their respective desired positions, the position adjustment of the first-side forming roll 60 and the second-side forming roll 70 is completed. Thereafter, the image forming device 20 operates to form an image on the recording medium P.

[0093] Next, the effects of this embodiment will be described. In image forming apparatus 20 as the image forming system of this embodiment, first-side forming roll 60 and second-side forming roll 70 are arranged so that the pressure (nip pressure) at nip portion N1 is higher at nip portion N1 located at the most downstream side (nip portion N1(K) in this embodiment) than at nip portion N1 located at the most upstream side (nip portion N1(V) in this embodiment). Here, image forming apparatus 20 can suppress color variation in the image transferred to transfer belt 42 compared to a configuration in which first-side forming roll 60 and second-side forming roll 70 are arranged so that the pressure at nip portion N1 is the same at nip portion N1 located at the most upstream side and nip portion N1 located at the most downstream side.

[0094] In the image forming apparatus 20 of this embodiment, the first-side forming roll 60 and the second-side forming roll 70 are arranged so that the contact surface TP2 is inclined with respect to the virtual plane TP1. Therefore, in the image forming apparatus 20, color variation in the image transferred to the transfer belt 42 can be suppressed compared to a configuration in which the first-side forming roll 60 and the second-side forming roll 70 are arranged so that the contact surface TP2 and the virtual plane TP1 are parallel.

[0095] As shown in FIG. 7 , in the image forming apparatus 20 of this embodiment, the contact portion of the first-side forming roll 60 with the transfer belt 42 is positioned closer to the primary transfer roll 44 than the virtual plane TP1 (i.e., lower in the vertical direction of the apparatus). Here, in the image forming apparatus 20, compared to a configuration in which the contact portion of the first-side forming roll 60 with the transfer belt 42 is positioned closer to the primary transfer roll 44 than the virtual plane TP1, the discharge initiation point P1 between the photosensitive drum 32 and the transfer belt 42 and the discharge initiation point P2 between the transfer belt 42 and the primary transfer roll 44 are spaced apart. This reduces the amount of discharge between the transfer belt 42 and the primary transfer roll 44, i.e., increases the toner charge, and reduces the amount of back-transfer to the most downstream photosensitive drum 32. This suppresses color variation in the image transferred to the transfer belt 42 in the image forming apparatus 20. It can be seen that the distance between the discharge initiation points P1 and P2 improves the primary transfer rate and the toner charge, as shown in FIGS. 9 and 10 . In the figure, "after measures" refers to an example in which the technology of the present disclosure is applied, and "before measures" refers to a comparative example in which the technology of the present disclosure is not suitable.

[0096] The image forming apparatus 20 of this embodiment is equipped with a first movement mechanism 62 that moves the first-side forming roll 60 toward the primary transfer roll 44 (downward in the device's vertical direction) relative to the virtual plane TP1. Therefore, in the image forming apparatus 20, color variation of the image transferred to the transfer belt 42 can be suppressed regardless of the image formation conditions (conditions such as the thickness of the recording medium P, the unevenness of the recording medium P, and the toner particle size) compared to a configuration in which the positional relationship of the first-side forming roll 60 relative to the virtual plane TP1 is fixed.

[0097] The image forming apparatus 20 of this embodiment includes a steering roll 48S that suppresses skew of the transfer belt 42. The contact portion of the second-side forming roll 70 with the transfer belt 42 is positioned on the opposite side of the virtual plane TP1 from the primary transfer roll 44 (upper side in the vertical direction of the apparatus). Therefore, in the image forming apparatus 20, the pressure pressing the transfer belt 42 against the photoreceptor drum 32 located at the most downstream position is higher than in a configuration in which the contact portion of the second-side forming roll 70 with the transfer belt 42 is positioned closer to the primary transfer roll 44 than the virtual plane TP1. This suppresses a decrease in the contact width in the rotational axis direction (width direction) of the transfer belt 42 due to tension wrinkles formed in the transfer belt 42 when suppressing skew of the transfer belt 42, thereby reducing the transfer rate difference. This suppresses color variation in the image transferred to the transfer belt 42 in the image forming apparatus 20. Note that, as shown in FIG. 11 , the primary transfer rate in the Δ-axis direction is improved by positioning the contact portion of the second-side forming roll 70 with the transfer belt 42 on the opposite side of the virtual plane TP1 from the primary transfer roll 44 (upper side in the vertical direction of the apparatus).

[0098] The image forming apparatus 20 of this embodiment is equipped with a second movement mechanism 72 that moves the second-side forming roll 70 to the side opposite the primary transfer roll 44 with respect to the virtual plane TP1 (to the upper side in the vertical direction of the apparatus). Therefore, in the image forming apparatus 20, color variation of the image transferred to the transfer belt 42 can be suppressed regardless of the image formation conditions (conditions such as the thickness of the recording medium P, the unevenness of the recording medium P, and the toner particle size), compared to a configuration in which the positional relationship of the second-side forming roll 70 with respect to the virtual plane TP1 is fixed.

[0099] In the image forming apparatus 20 of this embodiment, the first-side forming roll 60 and the second-side forming roll 70 are arranged so that the pressure in the nip portion N1 is higher at the nip portion N1 located downstream than at the nip portion N1 located upstream in the circumferential direction A. Therefore, in the image forming apparatus 20, color variation in the image transferred to the transfer belt 42 can be suppressed more effectively than in a configuration in which the first-side forming roll 60 and the second-side forming roll 70 are arranged so that the pressure in the nip portion N1 is the same at the nip portion N1 located most upstream and the nip portion N1 located most downstream in the circumferential direction A.

[0100] In image forming apparatus 20 of this embodiment, nip width W1 (W1(K) in this embodiment) located at the most downstream position in rotation direction A is wider than nip width W1 (W1(V) in this embodiment) located at the most upstream position, and nip width W2 (W2(K) in this embodiment) located at the most downstream position is narrower than nip width W2 (W2(V) in this embodiment) located at the most upstream position. Therefore, in image forming apparatus 20, color variation of the image transferred to transfer belt 42 can be suppressed compared to a configuration in which nip width W1 located at the most downstream position is the same as nip width W1 located at the most upstream position and nip width W2 located at the most downstream position is the same as nip width W2 located at the most upstream position in rotation direction A.

[0101] In image forming apparatus 20 of this embodiment, among photosensitive drums 32 adjacent to each other in circumferential direction A, nip width W1 located downstream is wider than nip width W1 located upstream, and nip width W2 located downstream is narrower than nip width W2 located upstream. Therefore, in image forming apparatus 20, it is possible to prevent an image from being transferred back to the most downstream photosensitive drum 32 due to the pressure pressing transfer belt 42 against the most downstream photosensitive drum 32.

[0102] In the image forming apparatus 20 of this embodiment, the processor 100 determines the positions of the first-side forming roll 60 and the second-side forming roll 70 relative to the virtual plane TP1 based on information about the particle size of the toner that forms the image, and operates the first movement mechanism 62 and the second movement mechanism 72 to move the first-side forming roll 60 and the second-side forming roll 70 to the determined positions, respectively. Therefore, in the image forming apparatus 20, color variation in the image transferred to the transfer belt 42 can be suppressed compared to a configuration in which the positions of the first-side forming roll 60 and the second-side forming roll 70 are fixed regardless of the particle size of the toner.

[0103] In the image forming apparatus 20 of this embodiment, the processor 100 increases the distance L between the first-side forming roll 60 and the second-side forming roll 70 in accordance with the particle size of the toner. In the image forming apparatus 20, the distance L between the first-side forming roll 60 and the second-side forming roll 70 is increased in accordance with the particle size of the toner. In other words, the inclination of the line connecting the vertices 60P, 70P of the first-side forming roll 60 and the second-side forming roll 70 with respect to the imaginary plane TP1 increases. Therefore, the image forming apparatus 20 can suppress color variation in the image transferred to the transfer belt 42 compared to a configuration in which the distance L between the first-side forming roll 60 and the second-side forming roll 70 is constant regardless of the particle size of the toner. By increasing the distance L between the first-side forming roll 60 and the second-side forming roll 70 in accordance with the particle size of the toner, the primary transfer pressure is improved, as shown in FIG. 12 . In FIG. 12 , plain paper is used as the paper.

[0104] (Other embodiments) In the embodiment described above, the processor 100 is configured to increase the distance L between the first-side forming roll 60 and the second-side forming roll 70 in accordance with the particle size of the toner, but the present disclosure is not limited to this configuration. For example, as shown in the flowcharts in Figures 14 and 15, the processor 100 may increase the distance L between the first-side forming roll 60 and the second-side forming roll 70 based on information regarding the thickness of the recording medium P to which the image is transferred and information regarding the unevenness of the recording medium P. The operation of the processor 100 will be described below using the flowcharts in Figures 14 and 15.

[0105] The processor 100 may determine the positions of the first surface forming roll 60 and the second surface forming roll 70 relative to the virtual plane TP1 based on information regarding the thickness of the recording medium P to which the image is transferred, and may operate the first moving mechanism 62 and the second moving mechanism 72 to move the first surface forming roll 60 and the second surface forming roll 70 to the determined positions, respectively.

[0106] Specifically, first, the processor 100 acquires information regarding the thickness of the recording medium P onto which the image is to be transferred. As an example, the processor 100 reads the information regarding the thickness of the recording medium P from the ROM 100B, the RAM 100C, or the storage unit 102. Note that the information regarding the thickness of the recording medium P may be acquired from a network or the like via the communication unit 108.

[0107] Next, the processor 100 determines the positions of the first-side forming roll 60 and the second-side forming roll 70 relative to the virtual plane TP1 based on the information about the thickness of the recording medium P. Specifically, the information about the thickness of the recording medium P is linked to the positions of the first-side forming roll 60 and the second-side forming roll 70 relative to the virtual plane TP1, and the processor 100 acquires the linked position information of the first-side forming roll 60 and the second-side forming roll 70 based on the information about the thickness of the recording medium P.

[0108] In this embodiment, as an example, the processor 100 increases the distance L between the first-side forming roll 60 and the second-side forming roll 70 in the direction perpendicular to the imaginary plane TP1 in accordance with the thickness of the recording medium P. Specifically, the processor 100 increases the distance L between the first-side forming roll 60 and the second-side forming roll 70 in the vertical direction of the device. In other words, the thicker the recording medium is, the more the processor 100 inclines the contact surface TP2 with respect to the imaginary plane TP1.

[0109] Next, the operation of adjusting the positions of the first surface forming roll 60 and the second surface forming roll 70 based on information regarding the thickness of the recording medium P to which the image is transferred using the image forming apparatus 20 of this embodiment will be explained using the flowchart shown in Figure 14.

[0110] First, the processor 100 obtains information about the thickness of the recording medium P onto which the image is to be transferred (step S210).

[0111] Next, the processor 100 determines the positions of the first-side forming roll 60 and the second-side forming roll 70 relative to the virtual plane TP1 based on the thickness of the recording medium P (step S212).

[0112] Then, the processor 100 operates the first movement mechanism 62 and the second movement mechanism 72 so that the first surface forming roll 60 and the second surface forming roll 70 move to the positions determined in step S212 (step S214).

[0113] When the first-side forming roll 60 and the second-side forming roll 70 move to their respective desired positions, the position adjustment of the first-side forming roll 60 and the second-side forming roll 70 is completed. Thereafter, the image forming device 20 operates to form an image on the recording medium P.

[0114] The processor 100 of the image forming apparatus 20 adjusts the positions of the first-side forming roll 60 and the second-side forming roll 70 based on information regarding the thickness of the recording medium P. This reduces color variation in the image transferred to the transfer belt 42 compared to a configuration in which the positions of the first-side forming roll 60 and the second-side forming roll 70 are fixed regardless of the thickness of the recording medium P. Furthermore, the processor 100 of the image forming apparatus 20 increases the distance L between the first-side forming roll 60 and the second-side forming roll 70 depending on the thickness of the recording medium P. This increases the inclination of the contact surface TP2 relative to the virtual plane TP1. This reduces color variation in the image transferred to the transfer belt 42 compared to a configuration in which the distance L between the first-side forming roll 60 and the second-side forming roll 70 is constant regardless of the thickness of the recording medium P. Increasing the distance L between the first-side forming roll 60 and the second-side forming roll 70 depending on the thickness of the recording medium P improves the primary transfer pressure, as shown in FIG. 13 . In the example of FIG. 13 , cardboard is used as the paper.

[0115] The processor 100 may determine the positions of the first surface forming roll 60 and the second surface forming roll 70 relative to the virtual plane TP1 based on information regarding the unevenness of the recording medium P to which the image is transferred, and operate the first moving mechanism 62 and the second moving mechanism 72 to move the first surface forming roll 60 and the second surface forming roll 70 to the determined positions, respectively.

[0116] Specifically, first, the processor 100 acquires information relating to the unevenness of the recording medium P onto which the image is to be transferred. As an example, the processor 100 reads the information relating to the unevenness of the recording medium P from the ROM 100B, the RAM 100C, or the storage unit 102. Note that the information relating to the unevenness of the recording medium P may be acquired from a network or the like via the communication unit 108.

[0117] Next, the processor 100 determines the positions of the first-surface forming roll 60 and the second-surface forming roll 70 relative to the virtual plane TP1 based on the information regarding the unevenness of the recording medium P. Specifically, the information regarding the unevenness of the recording medium P is linked to the positions of the first-surface forming roll 60 and the second-surface forming roll 70 relative to the virtual plane TP1, and the processor 100 acquires the linked position information of the first-surface forming roll 60 and the second-surface forming roll 70 based on the information regarding the unevenness of the recording medium P.

[0118] In this embodiment, as an example, the processor 100 increases the distance L between the first-surface forming roll 60 and the second-surface forming roll 70 in the direction perpendicular to the imaginary plane TP1 in accordance with the magnitude of the unevenness of the recording medium P. Specifically, the processor 100 increases the distance L between the first-surface forming roll 60 and the second-surface forming roll 70 in the vertical direction of the device. In other words, the greater the magnitude of the unevenness of the recording medium P, the more the processor 100 inclines the contact surface TP2 with respect to the imaginary plane TP1.

[0119] Next, the operation of adjusting the positions of the first surface forming roll 60 and the second surface forming roll 70 based on information regarding the unevenness of the recording medium P to which the image is transferred using the image forming apparatus 20 of this embodiment will be explained using the flowchart shown in Figure 15.

[0120] First, the processor 100 obtains information about the unevenness of the recording medium P onto which the image is to be transferred (step S220).

[0121] Next, the processor 100 determines the positions of the first-side forming roll 60 and the second-side forming roll 70 relative to the virtual plane TP1 based on the unevenness of the recording medium P (step S222).

[0122] Then, the processor 100 operates the first movement mechanism 62 and the second movement mechanism 72 so that the first surface forming roll 60 and the second surface forming roll 70 move to the positions determined in step S222 (step S224).

[0123] When the first-side forming roll 60 and the second-side forming roll 70 move to their respective desired positions, the position adjustment of the first-side forming roll 60 and the second-side forming roll 70 is completed. Thereafter, the image forming device 20 operates to form an image on the recording medium P.

[0124] The processor 100 of the image forming apparatus 20 adjusts the positions of the first-side forming roll 60 and the second-side forming roll 70 based on information about the unevenness of the recording medium P. This reduces color variation in the image transferred to the transfer belt 42 compared to a configuration in which the positions of the first-side forming roll 60 and the second-side forming roll 70 are fixed regardless of the unevenness of the recording medium P. Furthermore, the processor 100 of the image forming apparatus 20 increases the distance L between the first-side forming roll 60 and the second-side forming roll 70 depending on the size of the unevenness of the recording medium P (e.g., width or height difference), i.e., the inclination of the contact surface TP2 with respect to the virtual plane TP1 increases. This reduces color variation in the image transferred to the transfer belt 42 compared to a configuration in which the distance L between the first-side forming roll 60 and the second-side forming roll 70 is constant regardless of the size of the unevenness of the recording medium P. Note that by the processor 100 increasing the distance L between the first-side forming roll 60 and the second-side forming roll 70 depending on the unevenness of the recording medium P, the primary transfer pressure is improved, as shown in FIG. 13 . In the example of FIG. 13, embossed paper is used as the paper.

[0125] In the image forming apparatus of the above-described embodiment, the processor 100 can automatically adjust the tilt of the transfer belt 42 by controlling the first movement mechanism 62 and the second movement mechanism 72, but the present disclosure is not limited to this configuration. For example, the first movement mechanism 62 and the second movement mechanism 72 may be mechanisms that allow manual height adjustment. Also, two (or three) of information regarding the particle size of the toner, information regarding the thickness of the recording medium P, and information regarding the unevenness of the recording medium P may be combined, and the positions of the first-side forming roll 60 and the second-side forming roll 70 may be adjusted based on the combined conditions.

[0126] The present disclosure is not limited to the above-described embodiment, and various modifications, changes, and improvements are possible without departing from the spirit of the present disclosure. For example, the above-described modified examples may be appropriately combined to form a configuration.

[0127] The following additional notes are provided regarding the above-described embodiments.

[0128] (((1))) a plurality of image carriers for holding images; an intermediate transfer member that rotates and onto which images formed on the plurality of image carriers are transferred; a plurality of transfer members for transferring images formed on the plurality of image carriers to the intermediate transfer member; a first surface forming member disposed upstream of the plurality of image carriers in a rotation direction of the intermediate transfer member; a second surface forming member that is disposed downstream of the plurality of image carriers in the rotation direction and that stabilizes surface formation of the intermediate transfer body together with the first surface forming member; and The first surface forming member and the second surface forming member are disposed so that the pressure of a transfer portion formed by the image carrier and the transfer member via the intermediate transfer member is higher at a transfer portion located at the most downstream side in the rotation direction than at a transfer portion located at the most upstream side. Imaging system.

[0129] (((2))) The first surface forming member and the second surface forming member are arranged such that tangent surfaces that contact the vertices of the first surface forming member and the second surface forming member are inclined with respect to an imaginary plane that contacts the vertices of the image carrier. The image forming system according to (((1))).

[0130] (((3))) The image forming system according to (((2))), wherein a contact portion of the first surface forming member with the intermediate transfer body is disposed closer to the transfer member than the virtual surface.

[0131] (((4))) The image forming system according to (((3))), further comprising a first moving mechanism that moves the first surface forming member toward the transfer member relative to the virtual surface.

[0132] (((5))) a suppression mechanism that is provided downstream of the second surface forming member in the rotation direction and that suppresses skew of the intermediate transfer body, The image forming system according to (((2))), wherein a contact portion of the second surface forming member with the intermediate transfer body is disposed on the opposite side of the imaginary surface from the transfer member side.

[0133] (((6))) The image forming system according to (((5))), further comprising a second movement mechanism that moves the second surface forming member to the opposite side of the transfer member with respect to the virtual surface.

[0134] (((7))) The image forming system described in (((1))) or (((2))), wherein the first surface forming member and the second surface forming member are arranged so that the pressure of the transfer portion is higher at the transfer portion located downstream in the rotation direction than at the transfer portion located upstream.

[0135] (((8))) a nip width between the image carrier positioned at the most downstream side and the intermediate transfer body in the rotation direction is wider than a nip width between the image carrier positioned at the most upstream side and the intermediate transfer body; The image forming system according to any one of (((1))) to (((7))), wherein in the rotation direction, a nip width between the transfer member located at the most downstream position and the intermediate transfer body is narrower than a nip width between the transfer member located at the most upstream position and the intermediate transfer body.

[0136] (((9))) the image carriers adjacent to each other in the rotation direction have a nip width between the image carrier located downstream and the intermediate transfer body wider than a nip width between the image carrier located upstream and the intermediate transfer body; the nip width between the transfer member located downstream and the intermediate transfer body is narrower than the nip width between the transfer member located upstream and the intermediate transfer body, The image forming system according to (((8))).

[0137] (((10))) a first moving mechanism that moves the first surface forming member toward the transfer member with respect to the virtual surface; a second moving mechanism that moves the second surface forming member to an opposite side to the transfer member with respect to the virtual surface; a processor for controlling the operation of each of the first movement mechanism and the second movement mechanism; Further provided with The processor: determining the positions of the first surface forming member and the second surface forming member relative to the virtual surface based on information about the particle diameter of the toner that forms the image; operating the first moving mechanism and the second moving mechanism to move the first surface forming member and the second surface forming member to the determined positions, respectively; The image forming system according to (((2))).

[0138] (((11))) The image forming system described in (((10))), wherein the processor increases the distance between the first surface forming member and the second surface forming member in the direction perpendicular to the virtual plane depending on the particle size of the toner.

[0139] (((12))) a first moving mechanism that moves the first surface forming member toward the transfer member with respect to the virtual surface; a second moving mechanism that moves the second surface forming member to an opposite side to the transfer member with respect to the virtual surface; a processor for controlling the operation of each of the first movement mechanism and the second movement mechanism; Further provided with The processor: determining the positions of the first surface forming member and the second surface forming member relative to the virtual surface based on information about the thickness of the recording medium onto which the image is to be transferred; operating the first moving mechanism and the second moving mechanism to move the first surface forming member and the second surface forming member to the determined positions, respectively; The image forming system according to (((2))).

[0140] (((13))) The image forming system described in (((12))), wherein the processor increases the distance between the first surface forming member and the second surface forming member in the direction perpendicular to the virtual plane depending on the thickness of the recording medium.

[0141] (((14))) a first moving mechanism that moves the first surface forming member toward the transfer member with respect to the virtual surface; a second moving mechanism that moves the second surface forming member to an opposite side to the transfer member with respect to the virtual surface; a processor for controlling the operation of each of the first movement mechanism and the second movement mechanism; Further provided with The processor: determining the positions of the first surface forming member and the second surface forming member relative to the virtual surface based on information about the unevenness of the recording medium onto which the image is to be transferred; operating the first moving mechanism and the second moving mechanism to move the first surface forming member and the second surface forming member to the determined positions, respectively; The image forming system according to (((2))).

[0142] (((15))) The image forming system described in (((14)))), wherein the processor increases the distance between the first surface forming member and the second surface forming member in the direction perpendicular to the virtual surface depending on the size of the unevenness of the recording medium.

[0143] In the image forming system (((1))), color variation in the image transferred to the intermediate transfer body can be suppressed compared to a configuration in which a surface forming member is arranged to stabilize the surface formation of the intermediate transfer body so that the pressure of the transfer section formed by the image carrier and the transfer member via the intermediate transfer body is the same between the transfer section located most upstream and the transfer section located most downstream in the rotation direction of the intermediate transfer body.

[0144] In the image forming system (((2))), color variation of the image transferred to the intermediate transfer body can be suppressed compared to a configuration in which the first surface forming member and the second surface forming member are arranged so that the tangent surface and the virtual surface are parallel.

[0145] In the image forming system (((3))), color variation of the image transferred to the intermediate transfer body can be suppressed compared to a configuration in which the contact portion of the first surface forming member with the intermediate transfer body is positioned closer to the transfer member than the virtual surface.

[0146] In the image forming system (((4))), color variation of the image transferred to the intermediate transfer body can be suppressed regardless of the image forming conditions, compared to a configuration in which the positional relationship of the first surface forming member with respect to the virtual surface is fixed.

[0147] In the image forming system (((5))), color variation of the image transferred to the intermediate transfer body can be suppressed compared to a configuration in which the contact portion of the second surface forming member with the intermediate transfer body is positioned closer to the transfer member than the virtual surface.

[0148] In the image forming system (((6))), color variation of the image transferred to the intermediate transfer body can be suppressed regardless of the image forming conditions, compared to a configuration in which the positional relationship of the second surface forming member with respect to the virtual surface is fixed.

[0149] In the image forming system (((7))), color variation in the image transferred to the intermediate transfer body can be suppressed compared to a configuration in which the surface forming member is arranged so that the pressure at the transfer section is the same at the transfer section located most upstream and the transfer section located most downstream in the rotation direction of the intermediate transfer body.

[0150] In the image forming system (((8))), the nip width between the image carrier located at the most downstream position and the intermediate transfer member in the rotation direction of the intermediate transfer member is the same as the nip width between the image carrier located at the most upstream position and the intermediate transfer member, and the nip width between the transfer member located at the most downstream position and the intermediate transfer member is the same as the nip width between the transfer member located at the most upstream position and the intermediate transfer member, and this makes it possible to suppress color variation in the image transferred to the intermediate transfer member.

[0151] In the image forming system (((9))), the pressure of pressing the intermediate transfer body against the most downstream image carrier can prevent the image from being transferred back to the most downstream image carrier.

[0152] In the image forming system (((10))), color variation of the image transferred to the intermediate transfer body can be suppressed compared to a configuration in which the positions of the first surface forming member and the second surface forming member are fixed regardless of the particle size of the toner.

[0153] In the image forming system (((11))), color variation in the image transferred to the intermediate transfer body can be suppressed compared to a configuration in which the distance perpendicular to the virtual plane between the first surface forming member and the second surface forming member is constant regardless of the particle size of the toner.

[0154] In the image forming system (((12))), color variation of the image transferred to the intermediate transfer body can be suppressed compared to a configuration in which the positions of the first surface forming member and the second surface forming member are fixed regardless of the thickness of the recording medium.

[0155] In the image forming system (((13))), color variation in the image transferred to the intermediate transfer body can be suppressed compared to a configuration in which the distance perpendicular to the virtual plane between the first surface forming member and the second surface forming member is constant regardless of the thickness of the recording medium.

[0156] In the image forming system (((14))), color variation in the image transferred to the intermediate transfer body can be suppressed compared to a configuration in which the distance perpendicular to the virtual plane between the first surface forming member and the second surface forming member is constant regardless of the unevenness of the recording medium.

[0157] In the image forming system (((15))), color variation in the image transferred to the intermediate transfer body can be suppressed compared to a configuration in which the distance perpendicular to the virtual plane between the first surface forming member and the second surface forming member is constant regardless of the size of the unevenness of the recording medium. [Explanation of symbols]

[0158] 20 Image forming device 22 Image forming unit 24 Fixing section 24A heating roll 24B pressure roll 26 Image reading unit 30 Image forming unit 32 Photosensitive drum 34 Charger 36 Exposure equipment 38 Developing device 40 Transfer unit 42 Transfer belt 42A surface 44 Primary transfer roll 46 Secondary transfer roll 48 rolls 48B Opposed Roll 48D driving roll 48S steering roll 60 First surface forming roll 62 First movement mechanism 64 Main body 66 Mobile Unit 68 Bearing section 70 Second surface forming roll 72 Second movement mechanism 74 Main body 76 Mobile Unit 78 Bearing section 90 Image forming device 100 processors 102 Storage section 104 Operation section 106 Display section 108 Communications Department 110 Color measurement section A Circulation direction B Conveying direction N1 Nip section N2 nip P Recording medium TP1 Virtual Surface TP2 contact surface W1 Nip width W2 nip width

Claims

1. a plurality of image carriers for holding images; an intermediate transfer member that rotates and onto which images formed on the plurality of image carriers are transferred; a plurality of transfer members for transferring images formed on the plurality of image carriers to the intermediate transfer member; a first surface forming member disposed upstream of the plurality of image carriers in a rotation direction of the intermediate transfer member; a second surface forming member that is disposed downstream of the plurality of image carriers in the rotation direction and that stabilizes surface formation of the intermediate transfer body together with the first surface forming member; and The first surface forming member and the second surface forming member are disposed so that the pressure of a transfer portion formed by the image carrier and the transfer member via the intermediate transfer member is higher at a transfer portion located at the most downstream side in the rotation direction than at a transfer portion located at the most upstream side. Imaging system.

2. The first surface forming member and the second surface forming member are arranged such that tangent surfaces that contact the vertices of the first surface forming member and the second surface forming member are inclined with respect to an imaginary plane that contacts the vertices of the image carrier. The image forming system according to claim 1 .

3. The image forming system according to claim 2 , wherein a contact portion of the first surface forming member with the intermediate transfer body is disposed closer to the transfer member than the virtual surface.

4. The image forming system according to claim 3 , further comprising a first moving mechanism that moves the first surface forming member toward the transfer member with respect to the virtual surface.

5. a suppression mechanism that is provided downstream of the second surface forming member in the rotation direction and that suppresses skew of the intermediate transfer body, The image forming system according to claim 2 , wherein a contact portion of the second surface forming member with the intermediate transfer body is disposed on the side opposite to the transfer member side with respect to the virtual surface.

6. The image forming system according to claim 5 , further comprising a second movement mechanism that moves the second surface forming member to an opposite side of the transfer member with respect to the virtual surface.

7. 2. The image forming system according to claim 1, wherein the first surface forming member and the second surface forming member are arranged so that the pressure of the transfer portion is higher at the transfer portion located downstream in the rotation direction than at the transfer portion located upstream.

8. a nip width between the image carrier positioned at the most downstream side and the intermediate transfer body in the rotation direction is wider than a nip width between the image carrier positioned at the most upstream side and the intermediate transfer body; 2. The image forming system according to claim 1, wherein a nip width between the transfer member located at the most downstream position in the rotation direction and the intermediate transfer body is narrower than a nip width between the transfer member located at the most upstream position and the intermediate transfer body.

9. the image carriers adjacent to each other in the rotation direction have a nip width between the image carrier located downstream and the intermediate transfer body wider than a nip width between the image carrier located upstream and the intermediate transfer body; the nip width between the transfer member located downstream and the intermediate transfer body is narrower than the nip width between the transfer member located upstream and the intermediate transfer body, The image forming system according to claim 8 .

10. a first moving mechanism that moves the first surface forming member toward the transfer member with respect to the virtual surface; a second moving mechanism that moves the second surface forming member to an opposite side to the transfer member with respect to the virtual surface; a processor for controlling the operation of each of the first movement mechanism and the second movement mechanism; Further provided with The processor: determining the positions of the first surface forming member and the second surface forming member relative to the virtual surface based on information about the particle diameter of the toner that forms the image; operating the first moving mechanism and the second moving mechanism to move the first surface forming member and the second surface forming member to the determined positions, respectively; The image forming system according to claim 2 .

11. The image forming system according to claim 10 , wherein the processor increases the distance between the first surface forming member and the second surface forming member in the direction perpendicular to the imaginary plane in accordance with the particle size of the toner.

12. a first moving mechanism that moves the first surface forming member toward the transfer member with respect to the virtual surface; a second moving mechanism that moves the second surface forming member to an opposite side to the transfer member with respect to the virtual surface; a processor for controlling the operation of each of the first movement mechanism and the second movement mechanism; Further provided with The processor: determining the positions of the first surface forming member and the second surface forming member relative to the virtual surface based on information about the thickness of the recording medium onto which the image is to be transferred; operating the first moving mechanism and the second moving mechanism to move the first surface forming member and the second surface forming member to the determined positions, respectively; The image forming system according to claim 2 .

13. The image forming system according to claim 12 , wherein the processor increases the distance between the first surface forming member and the second surface forming member in the direction perpendicular to the virtual plane in accordance with the thickness of the recording medium.

14. a first moving mechanism that moves the first surface forming member toward the transfer member with respect to the virtual surface; a second moving mechanism that moves the second surface forming member to an opposite side to the transfer member with respect to the virtual surface; a processor for controlling the operation of each of the first movement mechanism and the second movement mechanism; Further provided with The processor: determining the positions of the first surface forming member and the second surface forming member relative to the virtual surface based on information about the unevenness of the recording medium onto which the image is to be transferred; operating the first moving mechanism and the second moving mechanism to move the first surface forming member and the second surface forming member to the determined positions, respectively; The image forming system according to claim 2 .

15. The image forming system according to claim 14 , wherein the processor increases the distance between the first surface forming member and the second surface forming member in the direction perpendicular to the virtual surface in accordance with the magnitude of the unevenness of the recording medium.

Images