Image forming system

Abstract

An image forming system includes: a plurality of image holding bodies that hold an image; an intermediate transfer body that rotates and transfers the image formed on the plurality of image holding bodies; a plurality of transfer members that transfer images formed on the plurality of image holding bodies to the intermediate transfer body; a first surface forming member disposed upstream of the plurality of image holding bodies in a rotational direction of the intermediate transfer body; and a second surface forming member that is disposed downstream of the plurality of image holding bodies in the rotation direction and stabilizes the 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 section formed by the image holding body and the transfer member via the intermediate transfer body is higher in the transfer section located at the most downstream in the rotation direction than in the transfer section located at the most upstream in the rotation direction.

Description

Technical Field

[0001] The present invention relates to an image forming system. Background Art

[0002] Patent document 1 discloses an image forming device, characterized in that it comprises: an image carrier that carries a developer image; a belt that is used to transfer the developer image on the image carrier; and a transfer component that contacts the back side of the belt. In the image forming device in which the image carrier contacts the surface of the belt, in the contact area between the image carrier and the belt in the moving direction of the belt, the belt contacts the transfer component in the downstream area in the moving direction of the belt, and does not contact the transfer component in the upstream area in the moving direction of the belt.

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2006-18177 Summary of the Invention

[0004] An object of the present invention is to suppress color variations of an image transferred to an intermediate transfer body, compared to a structure in which a surface forming component for stabilizing surface formation of an intermediate transfer body is configured in such a manner that the pressure of a transfer portion formed by an image retaining body and a transfer component via an intermediate transfer body is the same between a transfer portion located most upstream and a transfer portion located most downstream in the rotation direction of the intermediate transfer body.

[0005] The image forming system of the first embodiment of the present invention comprises: a plurality of image holders for holding images; an intermediate transfer body for rotating and transferring the images formed on the plurality of image holders; a plurality of transfer components for transferring the images formed on the plurality of image holders to the intermediate transfer body; a first surface forming component for being arranged at a position upstream of the intermediate transfer body in the direction of rotation of the plurality of image holders; and a second surface forming component for being arranged at a position downstream of the plurality of image holders in the direction of rotation and stabilizing the surface formation of the intermediate transfer body together with the first surface forming component, and the first surface forming component and the second surface forming component are arranged in such a manner that the pressure of the transfer portion formed by the image holder and the transfer component via the intermediate transfer body is higher at the transfer portion located most downstream in the direction of rotation than at the transfer portion located most upstream.

[0006] According to a second embodiment of the present invention, in the image forming system of the first embodiment, the first surface forming member and the second surface forming member are arranged so that the contact surfaces contacting the respective vertices of the first surface forming member and the second surface forming member are inclined relative to the virtual surface contacting the vertices of the image holding body.

[0007] According to a third aspect of the present invention, in the image forming system according to the second aspect, the contact portion of the first surface forming member with the intermediate transfer body is arranged closer to the transfer member than the virtual surface.

[0008] A fourth aspect of the present invention provides the image forming system according to the third aspect, further comprising a first moving mechanism that moves the first surface forming member toward the transfer member relative to the virtual surface.

[0009] The fifth mode of the present invention is further provided with, in the image forming system of the second mode, a suppression mechanism, which is arranged at a position further downstream in the rotation direction than the second surface forming component, to suppress the oblique movement of the intermediate transfer body, and the contact portion of the second surface forming component with the intermediate transfer body is arranged at a position further to the side opposite to the transfer component side than the virtual surface.

[0010] A sixth aspect of the present invention provides the image forming system according to the fifth aspect, further comprising a second moving mechanism for moving the second surface forming member toward a side opposite to the transfer member with respect to the virtual surface.

[0011] According to a seventh aspect of the present invention, in the image forming system of the first or second aspect, the first surface forming member and the second surface forming member are arranged so that the pressure of the transfer section is higher at the transfer section on the downstream side in the rotation direction than at the transfer section on the upstream side.

[0012] The 8th mode of the present invention is an image forming system of any one of the 1st to 7th modes, wherein the bite width between the image retaining body located most downstream in the rotation direction and the intermediate transfer body is wider than the bite width between the image retaining body located most upstream and the intermediate transfer body, and the bite width between the transfer component located most downstream in the rotation direction and the intermediate transfer body is narrower than the bite width between the transfer component located most upstream and the intermediate transfer body.

[0013] The 9th mode of the present invention is an image forming system of the 8th mode, wherein the bite width of the image retaining body located downstream among the image retaining bodies adjacent to each other in the rotation direction and the intermediate transfer body is wider than the bite width of the image retaining body located upstream and the intermediate transfer body, and the bite width of the transfer component located downstream among the transfer components adjacent to each other in the rotation direction and the intermediate transfer body is narrower than the bite width of the transfer component located upstream and the intermediate transfer body.

[0014] The tenth mode of the present invention is further provided with, in the image forming system of the second mode: a first moving mechanism for moving the first surface forming component relative to the virtual surface toward the transfer component side; a second moving mechanism for moving the second surface forming component relative to the virtual surface toward the side opposite to the transfer component; and a processor for controlling the respective actions of the first moving mechanism and the second moving mechanism, the processor performing the following processing: based on information related to the particle size of the toner forming the image, respectively calculating the positions of the first surface forming component and the second surface forming component relative to the virtual surface, driving the first moving mechanism and the second moving mechanism to move the first surface forming component and the second surface forming component to the respectively calculated positions.

[0015] According to an eleventh aspect of the present invention, in the image forming system according to the tenth aspect, the processor increases the distance between the first surface forming member and the second surface forming member in a perpendicular direction relative to the virtual surface according to a particle size of the toner.

[0016] The 12th mode of the present invention is further provided with, in the image forming system of the 2nd mode: a first moving mechanism for moving the first surface forming component relative to the virtual surface toward the transfer component side; a second moving mechanism for moving the second surface forming component relative to the virtual surface toward the side opposite to the transfer component; and a processor for controlling the respective actions of the first moving mechanism and the second moving mechanism, the processor performing the following processing: based on information related to the thickness of the recording medium to which the image is transferred, respectively calculating the positions of the first surface forming component and the second surface forming component relative to the virtual surface, driving the first moving mechanism and the second moving mechanism to move the first surface forming component and the second surface forming component to the respectively calculated positions.

[0017] According to a thirteenth aspect of the present invention, in the image forming system according to the twelfth aspect, the processor increases the distance between the first surface forming member and the second surface forming member in a perpendicular direction relative to the virtual surface according to the thickness of the recording medium.

[0018] The 14th mode of the present invention is further provided with, in the image forming system of the 2nd mode: a first moving mechanism for moving the first surface forming component relative to the virtual surface toward the transfer component side; a second moving mechanism for moving the second surface forming component relative to the virtual surface toward the side opposite to the transfer component; and a processor for controlling the respective actions of the first moving mechanism and the second moving mechanism, the processor performing the following processing: based on information related to the convexity and concavity of the recording medium to which the image is transferred, respectively calculating the positions of the first surface forming component and the second surface forming component relative to the virtual surface, and driving the first moving mechanism and the second moving mechanism to move the first surface forming component and the second surface forming component to the respectively calculated positions.

[0019] According to a fifteenth aspect of the present invention, in the image forming system according to the fourteenth aspect, the processor increases the distance between the first surface forming member and the second surface forming member in a perpendicular direction relative to the virtual surface according to the size of the unevenness of the recording medium.

[0020] Effects of the Invention

[0021] In the image forming system of the first mode, compared with a structure in which a surface forming member for stabilizing the surface formation of the intermediate transfer body is arranged in such a manner that the pressure of the transfer portion formed by the image retaining body and the transfer member via the intermediate transfer body is the same between the transfer portion located most upstream and the transfer portion located most downstream in the rotation direction of the intermediate transfer body, color fluctuations of the image transferred to the intermediate transfer body can be suppressed.

[0022] In the image forming system of the second aspect, color variation of the image transferred to the intermediate transfer body can be suppressed compared to a configuration in which the first and second surface forming members are arranged so that the contact surfaces are parallel to the virtual surface.

[0023] In the image forming system of the third aspect, 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 arranged closer to the transfer member than the virtual surface.

[0024] In the image forming system of the fourth aspect, compared with a configuration in which the positional relationship of the first surface forming member with respect to the virtual surface is fixed, color variation of the image transferred to the intermediate transfer member can be suppressed regardless of image forming conditions.

[0025] In the image forming system of the fifth aspect, 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 arranged closer to the transfer member than the virtual surface.

[0026] In the image forming system of the sixth aspect, compared with a configuration in which the positional relationship of the second surface forming member with respect to the virtual surface is fixed, color variation of the image transferred to the intermediate transfer body can be suppressed regardless of image forming conditions.

[0027] In the image forming system of the seventh mode, compared with a structure in which the surface forming component is arranged in such a manner that the pressure of the transfer section located most upstream and the transfer section located most downstream in the rotation direction of the intermediate transfer section is the same, the color variation of the image transferred to the intermediate transfer body can be suppressed.

[0028] In the image forming system of the 8th mode, compared with a structure in which the bite width of the image retaining body located at the most downstream and the intermediate transfer body in the rotation direction of the intermediate transfer body is the same as the bite width of the image retaining body located at the most upstream and the intermediate transfer body, and the bite width of the transfer component located at the most downstream and the intermediate transfer body is the same as the bite width of the transfer component located at the most upstream and the intermediate transfer body, the color change of the image transferred to the intermediate transfer body can be suppressed.

[0029] In the image forming system of the ninth aspect, it is possible to suppress reverse transfer of the image to the most downstream image holding member due to the pressure pressing the intermediate transfer member against the most downstream image holding member.

[0030] In the image forming system of the tenth aspect, 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 toner particle size.

[0031] In the image forming system of the eleventh aspect, color variation of the image transferred to the intermediate transfer body can be suppressed compared to a configuration in which the vertical distance between the first and second surface forming members relative to the virtual surface is constant regardless of the toner particle size.

[0032] In the image forming system of the twelfth aspect, 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.

[0033] In the image forming system of the thirteenth aspect, color variation of the image transferred to the intermediate transfer body can be suppressed compared to a structure in which the vertical distance between the first and second surface forming members relative to the virtual surface is fixed regardless of the thickness of the recording medium.

[0034] In the image forming system of the fourteenth aspect, color variation of the image transferred to the intermediate transfer member can be suppressed compared to a structure in which the vertical distances of the first and second surface forming members relative to the virtual surface are fixed regardless of the unevenness of the recording medium.

[0035] In the image forming system of the fifteenth aspect, color variation of the image transferred to the intermediate transfer member can be suppressed compared to a structure in which the vertical distance between the first and second surface forming members relative to the virtual surface is fixed regardless of the size of the concave and convex portions of the recording medium. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Embodiments of the present invention will be described in detail with reference to the following drawings.

[0037] Figure 1 is a schematic diagram showing an image forming apparatus according to one embodiment of the present invention;

[0038] Figure 2 is a block diagram showing a hardware configuration of an image forming apparatus according to one embodiment of the present invention;

[0039] Figure 3 is a schematic diagram showing a relationship between a virtual surface and a contact surface of an image forming apparatus according to one embodiment of the present invention;

[0040] Figure 4 yes Figure 1 An enlarged view of the periphery of the first surface forming member of the image forming apparatus shown;

[0041] Figure 5 yes Figure 1 An enlarged view of the periphery of the second surface forming member of the image forming apparatus shown;

[0042] Figure 6 yes Figure 1 An enlarged view of a transfer portion (nip portion) located at the most downstream side of the image forming apparatus shown;

[0043] Figure 7 yes Figure 1 An enlarged view of a transfer portion (nip portion) located at the most upstream side of the image forming apparatus shown;

[0044] Figure 8 This is a flowchart for explaining the operation when adjusting the positions of the first surface forming member and the second surface forming member of the image forming apparatus according to one embodiment of the present invention;

[0045] Figure 9 is a graph showing an improvement in the primary transfer rate when the image forming apparatus according to one embodiment of the present invention is used;

[0046] Figure 10 1 is a graph showing improvement in toner charge amount when the image forming apparatus according to one embodiment of the present invention is used;

[0047] Figure 11Graphs showing the position of the second surface forming member relative to the virtual surface and the improvement of the primary transfer rate in the Δ-axis direction in the image forming apparatus according to one embodiment of the present invention;

[0048] Figure 12 is a graph showing the relationship between the toner particle size and the nip pressure on the primary transfer roller when the image forming apparatus according to one embodiment of the present invention is used;

[0049] Figure 13 is a diagram showing the relationship between the type or thickness of paper and the nip pressure on the primary transfer roller when the image forming apparatus according to one embodiment of the present invention is used;

[0050] Figure 14 This is a flowchart for explaining the operation of adjusting the positions of the first surface forming member and the second surface forming member of the image forming apparatus according to another embodiment of the present invention.

[0051] Figure 15 This is a flowchart for explaining the operation when adjusting the positions of the first surface forming member and the second surface forming member of the image forming apparatus according to another embodiment of the present invention.

[0052] Explanation of symbols

[0053] 20-Image forming device, 22-Image forming unit, 24-Fixing unit, 24A-Heating roller, 24B-Pressure roller, 26-Image reading unit, 30-Image forming unit, 32-Photosensitive drum, 34-Charger, 36-Exposure device, 38-Developing device, 40-Transfer unit, 42-Transfer belt, 42A-Surface, 44-Primary transfer roller, 46-Secondary transfer roller, 48-Roller, 48B-Opposing roller, 48D-Drive roller, 48S-Steering roller, 60-First surface forming roller, 62-First moving mechanism, 64-Main Body, 66-moving portion, 68-bearing portion, 70-second surface forming roller, 72-second moving mechanism, 74-main body, 76-moving portion, 78-bearing portion, 90-image forming device, 100-processor, 102-storage portion, 104-operating portion, 106-display portion, 108-communication portion, 110-color measurement portion, A-circular direction, B-transmission direction, N1-biting portion, N2-biting portion, P-recording medium, TP1-virtual surface, TP2-contact surface, W1-biting width, W2-biting width. DETAILED DESCRIPTION

[0054] according to Figures 1 to 7 , an image forming apparatus 20 as an example of an image forming system according to an embodiment of the present invention will be described.

[0055] The arrow H shown in each figure indicates the vertical direction of the image forming apparatus 20 (specifically, the vertical direction). The arrow W indicates the width direction of the image forming apparatus 20 (specifically, the horizontal direction). The arrow D indicates the depth direction of the image forming apparatus 20 (specifically, the horizontal direction). The vertical direction, width direction, and depth direction of the image forming apparatus 20 intersect with each other (specifically, are orthogonal). The present invention is not limited to this structure; the width direction may be set as the depth direction, and the depth direction may be set as the width direction.

[0056] Furthermore, components denoted by the same reference numerals in the various drawings represent identical or similar components. Furthermore, in the embodiments described below, duplicate descriptions and reference numerals may be omitted. Furthermore, the drawings used in the following description are schematic, and the dimensional relationships and ratios of the components shown in the drawings may not necessarily correspond to reality. Furthermore, the dimensional relationships and ratios of the components may not necessarily correspond to reality across multiple drawings.

[0057] like Figure 1 As shown, 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. In this embodiment, paper is used as an example of the recording medium P, but the present invention is not limited to this.

[0058] The image forming apparatus 20 includes an image forming section 22 and a fixing section 24. Hereinafter, each section of the image forming apparatus 20 (the image forming section 22 and the fixing section 24) will be described.

[0059] (Image Forming Unit 22)

[0060] like Figure 1 As shown, 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 includes a plurality of image forming units 30 and a transfer section 40 .

[0061] On a surface 42A of a transfer belt 42, described later, a plurality of image forming units 30 are provided at intervals along the circumferential direction A of the transfer belt 42. The plurality of image forming units 30 form toner images of different colors on the surface 42A of the transfer belt 42. Furthermore, the image forming units 30 are arranged in order from upstream in the circumferential direction A: V (special color), Y (yellow), M (magenta), C (cyan), and K (black).

[0062] like Figure 1As shown in FIG. 1 , each image forming unit 30 is constructed in the same manner except for the toner used. Figure 1 , each image forming unit 30 is represented, and each part of the image forming unit 30 (V) is denoted by a reference numeral.

[0063] Each image forming unit 30 includes a photosensitive drum 32 as an example of an image holding member having a function of holding a toner image (image). The photosensitive drum 32 is oriented in one direction (eg, Figure 1 (clockwise in the direction of rotation).

[0064] Furthermore, each image forming unit 30 includes a charger 34 , an exposure device 36 , and a developing device 38 .

[0065] In each image forming unit 30, a charger 34 charges the photosensitive drum 32. Furthermore, an exposure device 36 exposes the photosensitive drum 32 charged by the charger 34 to light, thereby forming an electrostatic latent image on the photosensitive drum 32. Furthermore, a developing device 38 develops the electrostatic latent image formed on the photosensitive drum 32 by the exposure device 36, thereby forming a toner image.

[0066] The photoconductive drum 32 rotates while holding the electrostatic latent image formed as described above on its outer periphery, and the electrostatic latent image is transferred to the developing device 38 .

[0067] like Figure 1 As shown, the transfer unit 40 has a function of transferring the toner image formed by the image forming unit 30 to the recording medium P. Specifically, the transfer unit 40 performs primary transfer by overlapping the toner image of each photosensitive drum 32 with a transfer belt 42 as an example of an intermediate transfer body, and performs secondary transfer of the overlapped toner image to the recording medium P. Specifically, as shown in FIG. Figure 1 As shown, the transfer section 40 includes a transfer belt 42 , a primary transfer roller 44 , and a secondary transfer roller 46 .

[0068] The primary transfer rollers 44 are rollers that transfer the toner images on the photosensitive drums 32 onto the transfer belt 42 via the nip N1 between the photosensitive drums 32 and the primary transfer rollers 44. In this embodiment, a primary transfer electric field is applied between the primary transfer rollers 44 and the photosensitive drums 32, so that the toner images formed on the photosensitive drums 32 are transferred onto the transfer belt 42 via the nip N1. The primary transfer rollers 44 are one example of a transfer member.

[0069] The transfer belt 42 transfers the toner image from each photosensitive drum 32 to the surface 42A as the outer peripheral surface. Figure 1 As shown, the transfer belt 42 is an endless belt body, which is wound around a plurality of rollers 48 to determine its posture.

[0070] The transfer belt 42 is rotated in the direction of arrow A by the driving force from a driving source (not shown) among the plurality of rollers 48, such as the driving roller 48D. Figure 1 The roller 48S shown is a steering roller 48S as an example of a mechanism for suppressing the oblique movement of the transfer belt 42 (the width direction movement of the transfer belt 42, in other words, the axial movement of the roller 48). The steering roller 48S is located further downstream in the winding direction A than the second surface forming roller 70 described later. Figure 1 The roller 48B shown is the opposing roller 48B that opposes the secondary transfer roller 46 .

[0071] The secondary transfer roller 46 is a roller that transfers the toner image transferred onto the transfer belt 42 onto the recording medium P via the nip N2 between the opposing roller 48B and the secondary transfer roller 46. In this embodiment, a secondary transfer electric field is applied between the opposing roller 48B and the secondary transfer roller 46, thereby transferring the toner image transferred onto the transfer belt 42 onto the recording medium P via the nip N2.

[0072] And, as Figure 1 As shown, the transfer unit 40 includes a first surface forming roller 60 and a second surface forming roller 70. The first surface forming roller 60 is an example of a first surface forming member, and the second surface forming roller 70 is an example of a second surface forming member.

[0073] The first surface forming roller 60 is arranged at a position upstream of each image forming unit 30 in the circling direction A. Specifically, Figure 4 As shown, the first surface forming roller 60 is arranged between the image forming unit 30 (V) located most upstream in the circling direction A among the image forming units 30 and the driving roller 48D.

[0074] The second surface forming roller 70 is arranged at a position downstream of each image forming unit 30 in the circling direction A. Specifically, Figure 5 As shown, the second surface forming roller 70 is arranged between the image forming unit 30 (K) located most downstream in the circling direction A among the image forming units 30 and the switchback roller 48S.

[0075] The first surface forming roller 60 and the second surface forming roller 70 have a function of supporting the transfer belt 42 from the inner surface side to stabilize the surface formation of the transfer belt 42 .

[0076] The first surface forming roller 60 and the second surface forming roller 70 are arranged so that the pressure of the nip portion N1 as the transfer portion formed by the photosensitive drum 32 and the primary transfer roller 44 via the transfer belt 42 is higher at the nip portion N1 located most downstream in the circumferential direction A than at the nip portion N1 located most upstream.

[0077] Specifically, if Figures 3 to 5 As shown, the contact surface TP2 that contacts the vertices 60P and 70P of the first-surface forming roller 60 and the second-surface forming roller 70 is arranged in a state inclined relative to the virtual surface TP1 that contacts the vertex 32P of the photosensitive drum 32. In addition, the vertex 60P of the first-surface forming roller 60 is the vertex on the side opposite to the primary transfer roller 44, and in the present embodiment, it is the upper vertex in the vertical direction of the device. Furthermore, the vertex 70P of the second-surface forming roller 70 is the vertex on the side opposite to the primary transfer roller 44, and in the present embodiment, it is the upper vertex in the vertical direction of the device. Furthermore, the vertex 32P of the photosensitive drum 32 is the vertex on the primary transfer roller 44 side, and is the lower vertex in the vertical direction of the device.

[0078] More specifically, the contact portion of the first surface forming roller 60 with the transfer belt 42 is arranged closer to the primary transfer roller 44 than the virtual plane TP1 (see FIG. Figure 4 Then, the contact portion of the second surface forming roller 70 with the transfer belt 42 is arranged at a position on the side opposite to the primary transfer roller 44 side relative to the virtual surface TP1 (refer to Figure 5 ).

[0079] In the present embodiment, as described above, the first surface forming roller 60 and the second surface forming roller 70 are arranged so that the pressure of the nip portion N1 is higher at the downstream nip portion N1 than at the upstream nip portion N1 in the circumferential direction A. However, the present invention is not limited to this configuration.

[0080] And, as Figure 4 and Figure 5 As shown, the transfer unit 40 includes a first moving mechanism 62 and a second moving mechanism 72 .

[0081] The first moving mechanism 62 has a function of moving the first surface forming roller 60 relative to the virtual surface TP1 toward the primary transfer roller 44. As the first moving mechanism 62, for example, a ball screw mechanism, a cam mechanism, a rack and pinion mechanism, a pulley mechanism, a sprocket and chain mechanism, a gear mechanism, or the like, driven by an electric motor or an electric actuator, or the like, can be used.

[0082] As an example, the first moving mechanism 62 of this embodiment includes a main body portion 64 directly or indirectly attached to the main body of the image forming apparatus 20 and a moving portion 66 that moves relative to the main body portion 64. More specifically, Figure 4 As shown, in the first moving mechanism 62 , the main body 64 is directly or indirectly fixed to the main body of the image forming apparatus 20 , and the moving portion 66 moves relative to the main body 64 in the vertical direction of the apparatus.

[0083] The main body 64 includes a drive source (not shown) for moving the movable portion 66 relative to the main body 64. The drive source of the main body 64 is controlled by the processor 100, which will be described later. The processor 100 controls the relative movement of the movable portion 66 relative to the main body 64.

[0084] A pair of bearings 68 that rotatably support the first surface forming roller 60 are provided at the front end portion of the moving portion 66 .

[0085] The second moving mechanism 72 has a function of moving the second surface forming roller 70 relative to the virtual surface TP1 toward the side opposite to the primary transfer roller 44. As the second moving mechanism 72, for example, a ball screw mechanism, a cam mechanism, a rack and pinion mechanism, a pulley mechanism, a sprocket and chain mechanism, a gear mechanism, or the like, which uses an electric motor or an electric actuator as a driving source, can be used.

[0086] As an example, the second moving mechanism 72 of this embodiment includes a main body portion 74 directly or indirectly attached to the main body of the image forming apparatus 20 and a moving portion 76 that moves relative to the main body portion 74. More specifically, Figure 5 As shown, in the second moving mechanism 72 , a main body portion 74 is directly or indirectly fixed to the main body of the image forming apparatus 20 , and a moving portion 76 moves relative to the main body portion 74 in the apparatus vertical direction.

[0087] The main body 74 includes a drive source (not shown) for moving the moving portion 76 relative to the main body 74. The drive source of the main body 74 is controlled by the processor 100, which will be described later. The processor 100 controls the relative movement of the moving portion 66 relative to the main body 74.

[0088] A pair of bearings 78 that rotatably support the second surface forming roller 70 are provided at the front end portion of the moving portion 76 .

[0089] Furthermore, the positions of the first and second surface forming rollers 60 and 70 relative to the virtual surface TP1 are adjusted by the first moving mechanism 62 and the second moving mechanism 72, thereby changing the inclination of the contact surface TP2 relative to the virtual surface TP1. By changing the inclination of the contact surface TP2 relative to the virtual surface TP1, the contact pressure of the transfer belt 42 relative to the photosensitive drum 32 changes. In other words, by adjusting the inclination of the contact surface TP2 relative to the virtual surface TP1, the contact pressure of the transfer belt 42 relative to the photosensitive drum 32 can be adjusted.

[0090] And, as Figure 3As shown, in this embodiment, the contact portion of the first surface forming roller 60 with the transfer belt 42 is arranged at a position higher than the virtual surface TP1 in the vertical direction of the device, and the contact portion of the second surface forming roller 70 with the transfer belt 42 is arranged at a position lower than the virtual surface TP1 in the vertical direction of the device. Figure 3 As can be seen in FIG, the contact surface TP2 is inclined toward the circumferential direction A from the lower right toward the upper left.

[0091] In this embodiment, the contact surface TP2 is inclined relative to the virtual surface TP1 as described above, so Figure 6 and Figure 7 As shown, in the circling direction A, the nip width W1 between the photosensitive drum 32 located farthest downstream and the transfer belt 42 is wider than the nip width W1 between the photosensitive drum 32 located farthest upstream and the transfer belt 42. Specifically, the nip width W1(K) is wider than the nip width W1(V). Furthermore, in the circling direction A, the nip width W2 between the primary transfer roller 44 located farthest downstream and the transfer belt 42 is narrower than the nip width W2 between the primary transfer roller 44 located farthest upstream and the transfer belt 42. Specifically, the nip width W2(K) is narrower than the nip width W2(V).

[0092] Furthermore, in this embodiment, among the photosensitive drums 32 adjacent to each other in the circumferential direction A, the nip width W1 between the downstream photosensitive drum 32 and the transfer belt 42 can 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) can be wider than the nip width W1(C). Furthermore, among the primary transfer rollers 44 adjacent to each other in the circumferential direction A, the nip width W2 between the downstream primary transfer roller 44 and the transfer belt 42 can be narrower than the nip width W2 between the upstream primary transfer roller 44 and the transfer belt 42. For example, the nip width W2(Y) can be narrower than the nip width W2(V).

[0093] (Fixing section 24)

[0094] like Figure 1 As shown, the fixing unit 24 has the function of fixing the toner image transferred to the recording medium P by the secondary transfer roller 46 onto the recording medium P. Specifically, the fixing unit 24 includes a heating roller 24A as a heating member and a pressure roller 24B as a pressure member. In the fixing unit 24, the heating roller 24A and the pressure roller 24B heat and pressurize the recording medium P, thereby fixing the toner image formed on the recording medium P onto the recording medium P.

[0095] And, as Figure 2 As shown, 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.

[0096] (Processor 100)

[0097] 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 (I / O) interface 100D. The processor 100 controls the overall operation of the image forming apparatus 20. For example, the ROM 100B pre-stores various control programs and parameters. The RAM 100C is used as a workspace for the CPU 100A to execute various programs.

[0098] The storage unit 102 stores various programs, various data, application programs, and the like for executing print processing.

[0099] The operation unit 104 is used to input various information.

[0100] The display unit 106 is used to display various information.

[0101] The communication unit 108 is an interface for transmitting and receiving various data to and from external devices such as a server. The communication unit 108 can be configured to directly communicate with various devices using short-range wireless communication such as Wi-Fi (registered trademark) or Bluetooth (registered trademark).

[0102] 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 this embodiment includes the image reading unit 26 as an example, but the present invention is not limited to this configuration and the image reading unit 26 may not be included.

[0103] Moreover, if Figure 2 As shown, the components of the image forming apparatus 20 are electrically connected to each other via a system bus.

[0104] Next, the operation control of the first moving mechanism 62 and the second moving mechanism 72 by the processor 100 of this embodiment will be described.

[0105] The processor 100 can also calculate the positions of the first surface forming roller 60 and the second surface forming roller 70 relative to the virtual surface TP1 based on information related to the colorant particle size forming the image, and drive the first moving mechanism 62 and the second moving mechanism 72 to move the first surface forming roller 60 and the second surface forming roller 70 to the respectively calculated positions.

[0106] Specifically, processor 100 first acquires information on the particle size of toner forming the image. For example, the information on the particle size of the toner is read from ROM 100B, RAM 100C, or storage unit 102. Alternatively, the information on the particle size of the toner can be acquired from a network or the like via communication unit 108.

[0107] Next, the processor 100 calculates the positions of the first and second surface forming rollers 60 and 70 relative to the virtual plane TP1 based on the information regarding the toner particle size. Specifically, the information regarding the toner particle size is associated with the positions of the first and second surface forming rollers 60 and 70 relative to the virtual plane TP1. The processor 100 obtains the associated positional information of the first and second surface forming rollers 60 and 70 based on the information regarding the toner particle size.

[0108] In this embodiment, as an example, the processor 100 increases the vertical distance L between the first and second surface forming rollers 60 and 70 relative to the virtual surface TP1 based on the toner particle size. Specifically, the vertical distance L between the first and second surface forming rollers 60 and 70 is increased. In other words, the larger the toner particle size, the more inclined the contact surface TP2 is relative to the virtual surface TP1.

[0109] Next, use Figure 8 The flowchart shown here describes the operation when the positions of the first surface forming roller 60 and the second surface forming roller 70 of the image forming apparatus 20 of this embodiment are adjusted.

[0110] First, the processor 100 acquires information on the particle size of toner forming an image (step S200 ).

[0111] Next, the processor 100 obtains the positions of the first surface forming roller 60 and the second surface forming roller 70 relative to the virtual plane TP1 based on information on the toner particle diameter (step S202 ).

[0112] Then, the processor 100 drives the first moving mechanism 62 and the second moving mechanism 72 to move the first surface forming roller 60 and the second surface forming roller 70 to the positions respectively obtained in step S202 (step S204 ).

[0113] When the first and second surface forming rollers 60 and 70 move to their respective determined positions, the position adjustment of the first and second surface forming rollers 60 and 70 is completed.

[0114] Next, the effects of this embodiment will be described.

[0115] In the image forming apparatus 20, which serves as the image forming system of the present embodiment, the first surface forming roller 60 and the second surface forming roller 70 are arranged so that the pressure (nip pressure) on the nip portion N1 is higher at the nip portion N1 located most downstream (nip portion N1(K) in the present embodiment) than at the nip portion N1 located most upstream (nip portion N1(V) in the present embodiment). In the image forming apparatus 20, the color variation of the image transferred to the transfer belt 42 can be suppressed compared to a configuration in which the first surface forming roller 60 and the second surface forming roller 70 are arranged so that the pressure on the nip portion N1 is the same at the nip portion N1 located most upstream and at the nip portion N1 located most downstream.

[0116] The image forming apparatus 20 of this embodiment arranges the first plane forming roller 60 and the second plane forming roller 70 so that the contact surface TP2 is inclined relative to the virtual plane TP1. Therefore, in the image forming apparatus 20, compared with a configuration in which the first plane forming roller 60 and the second plane forming roller 70 are arranged so that the contact surface TP2 is parallel to the virtual plane TP1, it is possible to suppress color variation of the image transferred to the transfer belt 42.

[0117] like Figure 7 As shown, the contact portion of the first surface forming roller 60 of the image forming apparatus 20 of this embodiment with the transfer belt 42 is arranged at a position closer to the primary transfer roller 44 side than the virtual surface TP1 (the lower side in the vertical direction of the apparatus). Here, in the image forming apparatus 20, compared with the structure in which the contact portion of the first surface forming roller 60 with the transfer belt 42 is arranged at a position closer to the primary transfer roller 44 side than the virtual surface TP1, the discharge starting point P1 between the photosensitive drum 32 and the transfer belt 42 is separated from the discharge starting point P2 between the transfer belt 42 and the primary transfer roller 44, so the discharge amount between the transfer belt 42 and the primary transfer roller 44 is reduced, that is, the charge amount of the toner becomes higher, and the reverse transfer amount to the most downstream photosensitive drum 32 is reduced. As a result, in the image forming apparatus 20, color variations of the image transferred to the transfer belt 42 can be suppressed. In addition, since the discharge starting point P1 is separated from the discharge starting point P2, as shown in FIG. Figure 9 and Figure 10 As shown, the primary transfer rate and the toner charge amount are improved. In the figure, "after the application" refers to an example to which the technology of the present invention is applied, and "before the application" refers to a comparative example to which the technology of the present invention is not applied.

[0118] The image forming apparatus 20 of this embodiment includes a first moving mechanism 62 that moves the first surface forming roller 60 toward the primary transfer roller 44 (the lower side in the vertical direction of the apparatus) relative to the virtual surface TP1. Therefore, in the image forming apparatus 20, compared to a configuration in which the positional relationship of the first surface forming roller 60 relative to the virtual surface TP1 is fixed, it is possible to suppress color variations in the image transferred to the transfer belt 42 regardless of image forming conditions (such as the thickness of the recording medium P, the unevenness of the recording medium P, and the toner particle size).

[0119] The image forming apparatus 20 of this embodiment includes a steering roller 48S that suppresses skew movement of the transfer belt 42. The contact portion of the second surface forming roller 70 with the transfer belt 42 is located on the side of the image forming apparatus 20 that is opposite the primary transfer roller 44 side relative to the imaginary plane TP1 (upper in the vertical direction of the apparatus). Therefore, in the image forming apparatus 20, compared to a configuration in which the contact portion of the second surface forming roller 70 with the transfer belt 42 is located closer to the primary transfer roller 44 side relative to the imaginary plane TP1, the pressure pressing the transfer belt 42 against the photosensitive drum 32 located farthest downstream is increased. This suppresses the reduction in the contact width of the transfer belt 42 in the axial direction (width direction) of the rotational axis (width direction) caused by tension wrinkles in the transfer belt 42 formed when suppressing skew movement, thereby reducing transfer rate differences. Consequently, in the image forming apparatus 20, color variations in the image transferred to the transfer belt 42 can be suppressed. In addition, it can be seen that the contact portion of the second surface forming roller 70 with the transfer belt 42 is arranged at a position on the side opposite to the primary transfer roller 44 side (upper side in the vertical direction of the device) relative to the virtual surface TP1. Figure 11 As shown, the primary transfer ratio in the Δ-axis direction is improved.

[0120] The image forming apparatus 20 of this embodiment includes a second moving mechanism 72 that moves the second surface forming roller 70 relative to the virtual surface TP1 toward the side opposite to the primary transfer roller 44 (the upper side in the vertical direction of the apparatus). Therefore, in the image forming apparatus 20, compared to a configuration in which the positional relationship of the second surface forming roller 70 relative to the virtual surface TP1 is fixed, it is possible to suppress color variations in the image transferred to the transfer belt 42 regardless of image forming conditions (such as the thickness of the recording medium P, the unevenness of the recording medium P, and the toner particle size).

[0121] In the image forming apparatus 20 of this embodiment, the first surface forming roller 60 and the second surface forming roller 70 are arranged so that the pressure of the nip N1 is higher at the nip N1 located on the downstream side in the circling direction A than at the nip N1 located on the upstream side. Therefore, in the image forming apparatus 20, compared with a configuration in which the first surface forming roller 60 and the second surface forming roller 70 are arranged so that the pressure of the nip N1 is the same at the nip N1 located most upstream and at the nip N1 located most downstream in the circling direction A, color variation of the image transferred to the transfer belt 42 can be suppressed.

[0122] In the image forming apparatus 20 of this embodiment, the nip width W1 at the most downstream position (W1(K) in this embodiment) is wider than the nip width W1 at the most upstream position (W1(V) in this embodiment), and the nip width W2 at the most downstream position (W2(K) in this embodiment) is narrower than the nip width W2 at the most upstream position (W2(V) in this embodiment) in the circumferential direction A. Therefore, in the image forming apparatus 20, color variation of the image transferred to the transfer belt 42 can be suppressed compared to a configuration in which the nip width W1 at the most downstream position is the same as the nip width W1 at the most upstream position, and the nip width W2 at the most downstream position is the same as the nip width W2 at the most upstream position in the circumferential direction A.

[0123] In the image forming apparatus 20 of this embodiment, between adjacent photosensitive drums 32 in the circumferential direction A, the nip width W1 located downstream is wider than the nip width W1 located upstream, and the nip width W2 located downstream is narrower than the nip width W2 located upstream. Therefore, in the image forming apparatus 20, it is possible to suppress reverse transfer of the image to the downstreammost photosensitive drum 32 due to the pressure of the transfer belt 42 pressing against the downstreammost photosensitive drum 32.

[0124] In the image forming apparatus 20 of this embodiment, the processor 100 calculates the positions of the first and second surface forming rollers 60 and 70 relative to the virtual plane TP1 based on information regarding the particle size of the toner forming the image, and drives the first and second moving mechanisms 62 and 72 to move the first and second surface forming rollers 60 and 70 to the calculated positions. Therefore, in the image forming apparatus 20, color variation of the image transferred to the transfer belt 42 can be suppressed compared to a configuration in which the positions of the first and second surface forming rollers 60 and 70 are fixed regardless of the toner particle size.

[0125] Furthermore, in the image forming apparatus 20 of the present embodiment, the processor 100 lengthens the distance L between the first surface forming roller 60 and the second surface forming roller 70 according to the particle size of the toner. In the image forming apparatus 20, the distance L between the first surface forming roller 60 and the second surface forming roller 70 is lengthened according to the particle size of the toner, that is, the inclination angle of the straight line connecting the vertices 60P and 70P of the first surface forming roller 60 and the second surface forming roller 70 relative to the virtual plane TP1 becomes larger. Therefore, in the image forming apparatus 20, the color variation of the image transferred to the transfer belt 42 can be suppressed compared with the structure in which the distance L between the first surface forming roller 60 and the second surface forming roller 70 is fixed regardless of the particle size of the toner. In addition, by lengthening the distance L between the first surface forming roller 60 and the second surface forming roller 70 according to the particle size of the toner by the processor 100, as shown in FIG. Figure 12As shown in FIG, the primary transfer pressure is improved. Figure 12 In the , use plain paper as the paper.

[0126] (Other embodiments)

[0127] In the above embodiment, the processor 100 is configured to lengthen the distance L between the first surface forming roller 60 and the second surface forming roller 70 according to the particle size of the toner, but the present invention is not limited to this configuration. Figure 14 and Figure 15 As shown in the flowchart, the processor 100 can lengthen the distance L between the first-side forming roller 60 and the second-side forming roller 70 based on information about the thickness of the recording medium P to which the image is transferred and information about the concave-convexity of the recording medium P. Figure 14 and Figure 15 The flowchart shown in FIG. 1 illustrates the operation of the processor 100 .

[0128] The processor 100 can also calculate the positions of the first surface forming roller 60 and the second surface forming roller 70 relative to the virtual surface TP1 based on information related to the thickness of the recording medium P to which the image is transferred, and drive the first moving mechanism 62 and the second moving mechanism 72 to move the first surface forming roller 60 and the second surface forming roller 70 to the respectively calculated positions.

[0129] Specifically, the processor 100 first obtains information regarding the thickness of the recording medium P to which the image is transferred. For example, the information regarding the thickness of the recording medium P is read from the ROM 100B, RAM 100C, or storage unit 102. Alternatively, the information regarding the thickness of the recording medium P can be obtained from a network or the like via the communication unit 108.

[0130] Next, the processor 100 calculates the positions of the first and second surface forming rollers 60 and 70 relative to the virtual plane TP1 based on the information regarding the thickness of the recording medium P. Specifically, the information regarding the thickness of the recording medium P is associated with the positions of the first and second surface forming rollers 60 and 70 relative to the virtual plane TP1, and the processor 100 obtains the associated positional information of the first and second surface forming rollers 60 and 70 based on the information regarding the thickness of the recording medium P.

[0131] In this embodiment, as an example, the processor 100 increases the vertical distance L between the first and second surface forming rollers 60 and 70 relative to the virtual plane TP1 according to the thickness of the recording medium P. Specifically, the vertical distance L between the first and second surface forming rollers 60 and 70 is increased. In other words, the thicker the recording medium, the more inclined the contact surface TP2 is relative to the virtual plane TP1.

[0132] Next, use Figure 14 The flowchart shown here describes the operation of adjusting the positions of the first and second surface forming rollers 60 and 70 based on the information on the thickness of the recording medium P to which the image is transferred using the image forming apparatus 20 of this embodiment.

[0133] First, the processor 100 acquires information about the thickness of the recording medium P to which the image is transferred (step S210 ).

[0134] Next, the processor 100 obtains the positions of the first surface forming roller 60 and the second surface forming roller 70 relative to the virtual plane TP1 based on the thickness of the recording medium P (step S212 ).

[0135] Then, the processor 100 drives the first moving mechanism 62 and the second moving mechanism 72 to move the first surface forming roller 60 and the second surface forming roller 70 to the positions respectively obtained in step S212 (step S214 ).

[0136] When the first and second surface forming rollers 60 and 70 move to their respective determined positions, the position adjustment of the first and second surface forming rollers 60 and 70 is completed.

[0137] Since the processor 100 of the image forming apparatus 20 adjusts the positions of the first-side forming roller 60 and the second-side forming roller 70 based on information related to the thickness of the recording medium P, color variations of the image transferred to the transfer belt 42 can be suppressed compared to a structure in which the positions of the first-side forming roller 60 and the second-side forming roller 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 roller 60 and the second-side forming roller 70 based on the thickness of the recording medium P, that is, the inclination angle of the contact surface TP2 relative to the virtual surface TP1 becomes larger, thereby suppressing color variations of the image transferred to the transfer belt 42 compared to a structure in which the distance L between the first-side forming roller 60 and the second-side forming roller 70 is fixed regardless of the thickness of the recording medium P. In addition, by lengthening the distance L between the first-side forming roller 60 and the second-side forming roller 70 based on the thickness of the recording medium P, as shown in FIG. Figure 13 As shown in FIG, the primary transfer pressure is improved. Figure 13 In the example, thick paper is used as the paper.

[0138] The processor 100 can also calculate the positions of the first surface forming roller 60 and the second surface forming roller 70 relative to the virtual surface TP1 based on information related to the convexity and concavity of the recording medium P to which the image is transferred, and drive the first moving mechanism 62 and the second moving mechanism 72 to move the first surface forming roller 60 and the second surface forming roller 70 to the respectively calculated positions.

[0139] Specifically, the processor 100 first acquires information regarding the concavity and convexity of the recording medium P to which the image is transferred. For example, the information regarding the concavity and convexity of the recording medium P is read from the ROM 100B, RAM 100C, or storage unit 102. Alternatively, the information regarding the concavity and convexity of the recording medium P can be acquired from a network or the like via the communication unit 108.

[0140] Next, the processor 100 calculates the positions of the first and second surface forming rollers 60 and 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 associated with the positions of the first and second surface forming rollers 60 and 70 relative to the virtual plane TP1. The processor 100 obtains the associated positional information of the first and second surface forming rollers 60 and 70 based on the information regarding the unevenness of the recording medium P.

[0141] Furthermore, in this embodiment, as an example, the processor 100 increases the vertical distance L between the first and second surface forming rollers 60 and 70 relative to the virtual plane TP1 based on the size of the unevenness of the recording medium P. Specifically, the vertical distance L between the first and second surface forming rollers 60 and 70 is increased. In other words, the greater the unevenness of the recording medium P, the more inclined the contact surface TP2 is relative to the virtual plane TP1.

[0142] Next, use Figure 15 The flowchart shown here describes the operation of adjusting the positions of the first and second surface forming rollers 60 and 70 based on information on the concavity and convexity of the recording medium P to which the image is transferred using the image forming apparatus 20 of this embodiment.

[0143] First, the processor 100 acquires information on the concavity and convexity of the recording medium P to which the image is transferred (step S220 ).

[0144] Next, the processor 100 obtains the positions of the first surface forming roller 60 and the second surface forming roller 70 relative to the virtual plane TP1 based on the unevenness of the recording medium P (step S222 ).

[0145] Then, the processor 100 drives the first moving mechanism 62 and the second moving mechanism 72 to move the first surface forming roller 60 and the second surface forming roller 70 to the positions respectively obtained in step S222 (step S224 ).

[0146] When the first and second surface forming rollers 60 and 70 move to their respective determined positions, the position adjustment of the first and second surface forming rollers 60 and 70 is completed.

[0147] Since the processor 100 of the image forming apparatus 20 adjusts the positions of the first-side forming roller 60 and the second-side forming roller 70 based on information related to the concavity and convexity of the recording medium P, color variations of the image transferred to the transfer belt 42 can be suppressed compared to a structure in which the positions of the first-side forming roller 60 and the second-side forming roller 70 are fixed regardless of the concavity and convexity of the recording medium P. Furthermore, the processor 100 of the image forming apparatus 20 lengthens the distance L between the first-side forming roller 60 and the second-side forming roller 70 based on the size of the concavity and convexity of the recording medium P (for example, width, height difference), that is, the inclination angle of the contact surface TP2 relative to the virtual surface TP1 becomes larger, thereby making the distance L between the first-side forming roller 60 and the second-side forming roller 70 fixed regardless of the size of the concavity and convexity of the recording medium P, color variations of the image transferred to the transfer belt 42 can be suppressed compared to a structure in which the distance L between the first-side forming roller 60 and the second-side forming roller 70 is fixed regardless of the size of the concavity and convexity of the recording medium P. In addition, by lengthening the distance L between the first-side forming roller 60 and the second-side forming roller 70 based on the concavity and convexity of the recording medium P, as shown in FIG. Figure 13 As shown in FIG, the primary transfer pressure is improved. Figure 13 In this example, embossed paper is used as the paper.

[0148] In the image forming apparatus of the aforementioned embodiment, the inclination angle of the transfer belt 42 can be automatically adjusted by controlling the first and second moving mechanisms 62 and 72 via the processor 100. However, the present invention is not limited to this configuration. For example, the first and second moving mechanisms 62 and 72 may also be manually adjustable in height. Furthermore, any two (or three) of information related to toner particle size, information related to the thickness of the recording medium P, and information related to the unevenness of the recording medium P can be combined to adjust the positions of the first and second forming rollers 60 and 70 based on the combined conditions.

[0149] The present invention is not limited to the above-described embodiment, and various modifications, changes, and improvements can be made without departing from the spirit of the present invention. For example, the above-described modified examples can be appropriately combined in multiple configurations.

[0150] Regarding the above embodiment, the following supplementary notes are further disclosed. (1)

[0152] An image forming system comprising:

[0153] A plurality of image holding bodies for holding images;

[0154] an intermediate transfer body that rotates and transfers the images formed on the plurality of image holding bodies;

[0155] a plurality of transfer members for transferring the images formed on the plurality of image holding members to the intermediate transfer member;

[0156] a first surface forming member disposed upstream of the plurality of image holding members in the rotational direction of the intermediate transfer member; and

[0157] The second surface forming member is arranged at a position downstream of the plurality of image holding members in the rotation direction and stabilizes the surface formation of the intermediate transfer member together with the first surface forming member.

[0158] The first and second surface forming members are arranged so that the pressure of the transfer portion formed by the image holding member and the transfer member via the intermediate transfer member is higher at the transfer portion located most downstream in the rotational direction than at the transfer portion located most upstream. (2)

[0160] The image forming system according to (1), wherein

[0161] The first and second surface forming members are arranged so that their contact surfaces with respective vertices are inclined relative to a virtual surface with vertices of the image holder. (3)

[0163] The image forming system according to (2), wherein

[0164] A portion of the first surface forming member that contacts the intermediate transfer body is disposed closer to the transfer member than the virtual surface. (4)

[0166] The image forming system according to (3), further comprising:

[0167] The first moving mechanism moves the first surface forming member toward the transfer member relative to the virtual surface. (5)

[0169] The image forming system according to claim (2), further comprising:

[0170] The suppressing mechanism is provided at a position downstream of the second surface forming member in the rotation direction and suppresses the oblique movement of the intermediate transfer body.

[0171] The contact portion of the second surface forming member with the intermediate transfer body is arranged on a side opposite to the transfer member side relative to the virtual surface. (6)

[0173] The image forming system according to (5), further comprising:

[0174] The second moving mechanism moves the second surface forming member toward a side opposite to the transfer member with respect to the virtual surface. (7)

[0176] The image forming system according to (1) or (2), wherein:

[0177] The first surface forming member and the second surface forming member are arranged so that the pressure of the transfer section is higher in the transfer section located downstream in the rotation direction than in the transfer section located upstream. (8)

[0179] The image forming system according to any one of (1) to (7), wherein

[0180] The nip width between the image holding member located most downstream and the intermediate transfer member in the rotation direction is wider than the nip width between the image holding member located most upstream and the intermediate transfer member.

[0181] The nip width between the transfer member located most downstream in the rotational direction and the intermediate transfer body is narrower than the nip width between the transfer member located most upstream and the intermediate transfer body. (9)

[0183] The image forming system according to (8), wherein

[0184] The width of engagement between the image holding body located downstream and the intermediate transfer body among the image holding bodies adjacent to each other in the rotational direction is wider than the width of engagement between the image holding body located upstream and the intermediate transfer body.

[0185] The nip width between the transfer member located downstream and the intermediate transfer body among the transfer members adjacent to each other in the rotation direction is narrower than the nip width between the transfer member located upstream and the intermediate transfer body. (10)

[0187] The image forming system according to (2), further comprising:

[0188] a first moving mechanism for moving the first surface forming member toward the transfer member relative to the virtual surface;

[0189] a second moving mechanism for moving the second surface forming member relative to the virtual surface toward a side opposite to the transfer member; and

[0190] a processor to control the respective actions of the first moving mechanism and the second moving mechanism;

[0191] The processor performs the following processing:

[0192] The positions of the first surface forming member and the second surface forming member relative to the virtual surface are respectively determined based on information on the particle diameter of the toner forming the image.

[0193] The first moving mechanism and the second moving mechanism are driven to move the first surface forming member and the second surface forming member to the respectively obtained positions. (11)

[0195] The image forming system according to (10), wherein

[0196] The processor increases a distance between the first surface forming member and the second surface forming member in a perpendicular direction relative to the virtual surface according to a particle size of the toner. (12)

[0198] The image forming system according to claim (2), further comprising:

[0199] a first moving mechanism for moving the first surface forming member toward the transfer member relative to the virtual surface;

[0200] a second moving mechanism for moving the second surface forming member relative to the virtual surface toward a side opposite to the transfer member; and

[0201] a processor to control the respective actions of the first moving mechanism and the second moving mechanism;

[0202] The processor performs the following processing:

[0203] The positions of the first surface forming member and the second surface forming member relative to the virtual surface are respectively determined based on information on the thickness of the recording medium to which the image is transferred.

[0204] The first moving mechanism and the second moving mechanism are driven to move the first surface forming member and the second surface forming member to the respectively obtained positions. (13)

[0206] The image forming system according to (12), wherein

[0207] The processor increases the distance between the first surface forming member and the second surface forming member in a perpendicular direction relative to the virtual surface according to the thickness of the recording medium. (14)

[0209] The image forming system according to (2), further comprising:

[0210] a first moving mechanism for moving the first surface forming member toward the transfer member relative to the virtual surface;

[0211] a second moving mechanism for moving the second surface forming member relative to the virtual surface toward a side opposite to the transfer member; and

[0212] a processor to control the respective actions of the first moving mechanism and the second moving mechanism;

[0213] The processor performs the following processing:

[0214] The positions of the first surface forming member and the second surface forming member relative to the virtual surface are respectively determined based on information on the concavity and convexity of the recording medium to which the image is transferred.

[0215] The first moving mechanism and the second moving mechanism are driven to move the first surface forming member and the second surface forming member to the respectively obtained positions. (15)

[0217] The image forming system according to (14), wherein

[0218] The processor increases the distance between the first surface forming member and the second surface forming member in a perpendicular direction relative to the virtual surface according to the size of the unevenness of the recording medium.

[0219] In the image forming system of (1), compared with a structure in which a surface forming member for stabilizing the surface formation of the intermediate transfer body is configured in such a manner that the pressure of the transfer portion formed by the image retaining body and the transfer member via the intermediate transfer body is the same between the transfer portion located most upstream and the transfer portion located most downstream in the rotation direction of the intermediate transfer body, color variation of the image transferred to the intermediate transfer body can be suppressed.

[0220] In the image forming system of (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 contact surface is parallel to the virtual surface.

[0221] In the image forming system of (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 arranged closer to the transfer member than the virtual surface.

[0222] In the image forming system of (4), compared with a configuration in which the positional relationship of the first surface forming member with respect to the virtual surface is fixed, color variation of the image transferred to the intermediate transfer body can be suppressed regardless of image forming conditions.

[0223] In the image forming system of (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 arranged closer to the transfer member than the virtual surface.

[0224] In the image forming system of (6), compared with a configuration in which the positional relationship of the second surface forming member with respect to the virtual surface is fixed, color variation of the image transferred to the intermediate transfer body can be suppressed regardless of image forming conditions.

[0225] In the image forming system of (7), compared with a structure in which the surface forming member is arranged in such a manner that the pressure of the transfer portion located most upstream and the transfer portion located most downstream in the rotation direction of the intermediate transfer body is the same, the color variation of the image transferred to the intermediate transfer body can be suppressed.

[0226] In the image forming system of (8), the color variation of the image transferred to the intermediate transfer body can be suppressed compared with a structure in which the bite width of the image retaining body located at the most downstream and the intermediate transfer body in the rotation direction of the intermediate transfer body is the same as the bite width of the image retaining body located at the most upstream and the intermediate transfer body, and the bite width of the transfer component located at the most downstream and the intermediate transfer body is the same as the bite width of the transfer component located at the most upstream and the intermediate transfer body.

[0227] In the image forming system of (9), it is possible to suppress the reverse transfer of the image to the most downstream image holding member due to the pressure of pressing the intermediate transfer member against the most downstream image holding member.

[0228] In the image forming system of (10), color variation of the image transferred to the intermediate transfer body can be suppressed compared to a structure 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.

[0229] In the image forming system of (11), color variation of the image transferred to the intermediate transfer body can be suppressed compared to a structure in which the vertical distance between the first surface forming member and the second surface forming member relative to the virtual surface is fixed regardless of the particle size of the toner.

[0230] In the image forming system of (12), color variation of the image transferred to the intermediate transfer member can be suppressed compared to a structure 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.

[0231] In the image forming system of (13), color variation of the image transferred to the intermediate transfer body can be suppressed compared to a structure in which the vertical distance between the first surface forming member and the second surface forming member relative to the virtual surface is fixed regardless of the thickness of the recording medium.

[0232] In the image forming system of (14), color variation of the image transferred to the intermediate transfer body can be suppressed compared to a structure in which the vertical distance between the first surface forming member and the second surface forming member relative to the virtual surface is fixed regardless of the concavity and convexity of the recording medium.

[0233] In the image forming system of (15), color variation of the image transferred to the intermediate transfer body can be suppressed compared to a structure in which the vertical distance between the first surface forming member and the second surface forming member relative to the virtual surface is fixed regardless of the size of the concave and convex portions of the recording medium.

[0234] The above-described embodiments of the present invention are provided for the purpose of illustration and explanation. In addition, the embodiments of the present invention do not fully and exhaustively include the present invention, and do not limit the present invention to the disclosed embodiments. It is obvious that various modifications and variations are self-evident to those skilled in the art to which the present invention belongs. The present embodiment is selected and described in order to most easily explain the principles of the present invention and its application. Thus, other technical personnel in this field can understand the present invention through various modifications optimized for specific uses of the assumed various embodiments. The scope of the present invention is defined by the above claims and their equivalents.

Claims

1. An image forming system comprising: A plurality of image holding bodies for holding images; an intermediate transfer body that rotates and transfers the images formed on the plurality of image holding bodies; a plurality of transfer members for transferring the images formed on the plurality of image holding members to the intermediate transfer member; a first surface forming member disposed upstream of the plurality of image holding members in the rotational direction of the intermediate transfer member; and The second surface forming member is arranged at a position downstream of the plurality of image holding members in the rotation direction and stabilizes the surface formation of the intermediate transfer member together with the first surface forming member. The first and second surface forming members are arranged so that the pressure of the transfer portion formed by the image holding member and the transfer member via the intermediate transfer member is higher at the transfer portion located most downstream in the rotational direction than at the transfer portion located most upstream.

2. The image forming system according to claim 1, wherein The first and second surface forming members are arranged so that their contact surfaces with respective vertices are inclined relative to a virtual surface with vertices of the image holder.

3. The image forming system according to claim 2, wherein: A portion of the first surface forming member that contacts 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: The first moving mechanism moves the first surface forming member toward the transfer member relative to the virtual surface.

5. The image forming system according to claim 2, further comprising: The suppressing mechanism is provided at a position downstream of the second surface forming member in the rotation direction and suppresses the oblique movement of the intermediate transfer body. The contact portion of the second surface forming member with the intermediate transfer body is arranged on a side opposite to the transfer member side relative to the virtual surface.

6. The image forming system according to claim 5, further comprising: The second moving mechanism moves the second surface forming member toward a side opposite to the transfer member with respect to the virtual surface.

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

8. The image forming system according to any one of claims 1 to 7, wherein: The nip width between the image holding member located most downstream and the intermediate transfer member in the rotation direction is wider than the nip width between the image holding member located most upstream and the intermediate transfer member. The nip width between the transfer member located most downstream in the rotational direction and the intermediate transfer body is narrower than the nip width between the transfer member located most upstream and the intermediate transfer body.

9. The image forming system according to claim 8, wherein: The width of engagement between the image holding body located downstream and the intermediate transfer body among the image holding bodies adjacent to each other in the rotation direction is wider than the width of engagement between the image holding body located upstream and the intermediate transfer body. The nip width between the transfer member located downstream and the intermediate transfer body among the transfer members adjacent to each other in the rotation direction is narrower than the nip width between the transfer member located upstream and the intermediate transfer body.

10. The image forming system according to claim 2, further comprising: a first moving mechanism for moving the first surface forming member toward the transfer member relative to the virtual surface; a second moving mechanism for moving the second surface forming member relative to the virtual surface toward a side opposite to the transfer member; and a processor to control the respective actions of the first moving mechanism and the second moving mechanism; The processor performs the following processing: The positions of the first surface forming member and the second surface forming member relative to the virtual surface are respectively determined based on information on the particle diameter of the toner forming the image. The first moving mechanism and the second moving mechanism are driven to move the first surface forming member and the second surface forming member to the respectively obtained positions.

11. The image forming system according to claim 10, wherein: The processor increases a distance between the first surface forming member and the second surface forming member in a perpendicular direction relative to the virtual surface according to a particle size of the toner.

12. The image forming system according to claim 2, further comprising: a first moving mechanism for moving the first surface forming member toward the transfer member relative to the virtual surface; a second moving mechanism for moving the second surface forming member relative to the virtual surface toward a side opposite to the transfer member; and a processor to control the respective actions of the first moving mechanism and the second moving mechanism; The processor performs the following processing: The positions of the first surface forming member and the second surface forming member relative to the virtual surface are respectively determined based on information on the thickness of the recording medium to which the image is transferred. The first moving mechanism and the second moving mechanism are driven to move the first surface forming member and the second surface forming member to the respectively obtained positions.

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 a perpendicular direction relative to the virtual surface according to the thickness of the recording medium.

14. The image forming system according to claim 2, further comprising: a first moving mechanism for moving the first surface forming member toward the transfer member relative to the virtual surface; a second moving mechanism for moving the second surface forming member relative to the virtual surface toward a side opposite to the transfer member; and a processor to control the respective actions of the first moving mechanism and the second moving mechanism; The processor performs the following processing: The positions of the first surface forming member and the second surface forming member relative to the virtual surface are respectively determined based on information on the concavity and convexity of the recording medium to which the image is transferred. The first moving mechanism and the second moving mechanism are driven to move the first surface forming member and the second surface forming member to the respectively obtained positions.

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 a perpendicular direction relative to the virtual surface according to the size of the unevenness of the recording medium.

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