Image forming system

Abstract

An image forming system has: a ring-shaped intermediate transfer body wound around a plurality of rollers and moving along a circumferential direction to transfer a toner image once transferred to an outer peripheral surface; a transfer rotary body in contact with the intermediate transfer body while rotating and transferring the toner image of the intermediate transfer body to a medium at a secondary transfer position opposite to the intermediate transfer body; an opposite rotary body in contact with the intermediate transfer body while rotating and opposite to the transfer rotary body and forming a potential difference between the transfer rotary body; a guide portion provided at a position upstream of the medium in a conveyance direction from the secondary transfer position and guiding the medium to the secondary transfer position; and a moving portion moving the entire medium contact portion in the guide portion in a direction approaching or away from the intermediate transfer body while maintaining a posture in a direction intersecting a line connecting a center of the transfer rotary body and a center of the opposite rotary body, according to a kind of the medium.

Description

Technical Field

[0001] This invention relates to an image forming system. Background Technology

[0002] Patent Document 1 discloses an image forming apparatus comprising an intermediate transfer belt, a secondary transfer member, an annular secondary transfer belt, a counter member, and a contact width changing mechanism. The intermediate transfer belt is tensioned on multiple rollers and conveys a toner image through its outer peripheral surface. The secondary transfer member transfers the toner image from the intermediate transfer belt onto a recording medium at a secondary transfer position opposite to the intermediate transfer belt. The secondary transfer belt is wound around the secondary transfer member, rotating through the member and being clamped by both the member and the intermediate transfer belt. The counter member abuts against the inner peripheral surface of the intermediate transfer belt and is positioned opposite the secondary transfer member at the secondary transfer position, clamping the secondary transfer belt. The contact width changing mechanism changes the contact width of the contact area formed by the contact between a portion of the peripheral surface of the intermediate transfer belt and a portion of the peripheral surface of the secondary transfer belt at the secondary transfer position, based on the paper properties of the recording medium. Specifically, the contact width changing mechanism changes the contact width of the contact area between a predetermined first contact width and a second contact width that increases the contact width on the upstream side in the paper conveying direction by a large amount.

[0003] Patent Document 2 discloses an image forming apparatus comprising an image carrier, a transfer mechanism, a recording material conveying mechanism, and a recording material guiding mechanism. The image carrier carries a visible image formed by a charged pigment. The transfer mechanism transfers the visible image from the image carrier onto a recording material. The recording material conveying mechanism conveys the recording material to a transfer section between the transfer mechanism and the image carrier. The recording material guiding mechanism is disposed in the conveying path between the recording material conveying mechanism and the transfer section, and restricts the entry posture of the recording material into the transfer section. The recording material guiding mechanism includes a movable guiding member disposed on the image carrier side, at least downstream of the recording material conveying direction, which is movable along the image carrier direction.

[0004] Patent Document 3 discloses an image forming apparatus comprising one or more image holders, a thin-walled intermediate transfer body, a primary transfer member, a secondary transfer member, a surface adjustment member, and a tension adjustment member. The one or more image holders form and hold images of various color components based on various color component toners. The intermediate transfer body is opposed to the image holders and is cyclically conveyed by multiple tensioning members, and is temporarily held before the images of various color components formed by the image holders are transferred to recording material. The primary transfer member is disposed on the back side of the intermediate transfer body opposite the image holders, and forms a transfer electric field in the primary transfer area between the primary transfer member and the image holders, thereby transferring the images of various color components held on the image holders to the intermediate transfer body. A secondary transfer component is positioned opposite and in contact with a tensioning component disposed on the back side of the intermediate transfer body, forming a transfer electric field in the secondary transfer zone between the component and the tensioning component. This transfers the color component images transferred to the intermediate transfer body by the primary transfer component onto the recording material. A surface adjustment component is positioned upstream of the intermediate transfer body in the transport direction, closer to the secondary transfer component, and is configured to move back and forth in a direction intersecting the surface direction of the intermediate transfer body to form a transport trajectory surface of the intermediate transfer body reaching the secondary transfer zone. A tension adjustment component adjusts the tension of the intermediate transfer body in a manner that counteracts the slack in the intermediate transfer body caused by the movement of the surface adjustment component from a predetermined position.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2014-134614

[0006] Patent Document 2: Japanese Patent Application Publication No. 11-143254

[0007] Patent Document 3: Japanese Patent Application Publication No. 2014-191100 Summary of the Invention

[0008] The object of the present invention is to obtain an image forming system that can suppress the generation of image quality defects compared to a case where only one end of the guide portion of the medium is moved laterally toward or away from the intermediate transfer body in the direction of transmission.

[0009] The image forming system according to the first method comprises: an annular intermediate transfer body wound on multiple rollers and moving along the circumferential direction to convey a toner image transferred once onto the outer peripheral surface; a transfer rotating body that rotates while contacting the intermediate transfer body and transfers the toner image of the intermediate transfer body onto a medium at a secondary transfer position opposite to the intermediate transfer body; a counter rotating body that rotates while clamping the intermediate transfer body and opposing the transfer rotating body, and forms a potential difference between the two bodies; a guide section disposed at an upstream position relative to the secondary transfer position in the transport direction of the medium, and guides the medium to the secondary transfer position; and a moving section that, depending on the type of medium, moves the entire media contact portion in the guide section toward or away from the intermediate transfer body while maintaining an orientation that intersects the line connecting the center of the transfer rotating body and the center of the counter rotating body.

[0010] In the image forming system of the second method, when the medium is a medium or film medium that is thicker than a predetermined thickness, the moving part moves the entire medium contact portion in the guide part toward the intermediate transfer body relative to the predetermined thickness of the medium.

[0011] In the image forming system described in the first or second embodiment, when the medium is a medium with a surface smoother than a specified smoothness, the moving part causes the entire medium contact portion in the guide part to move away from the intermediate transfer body compared to a medium with the specified smoothness.

[0012] In the image forming system described in any of the first to third embodiments, the moving part moves the entire media contact portion in the guide part toward or away from the intermediate transfer body according to the secondary transfer voltage applied to the transfer rotating body or the opposing rotating body.

[0013] In the image forming system of the fifth method, when the secondary transfer voltage is higher than the reference voltage, compared to when the secondary transfer voltage is lower than the reference voltage, the moving part moves the entire media contact portion in the guide part toward the intermediate transfer body.

[0014] The image forming system according to the sixth embodiment, in any one of the first to fifth embodiments, includes: a rotating member that contacts the inner side of the intermediate transfer body at a position further downstream of the intermediate transfer body in the circumferential direction than the primary transfer position where the toner image is transferred to the intermediate transfer body and further upstream of the intermediate transfer body in the circumferential direction than the opposing rotating member; and the contact point where the medium guided by the guide portion contacts the intermediate transfer body is located at a position further downstream of the intermediate transfer body in the circumferential direction than the rotating member.

[0015] In the image forming system described in any of the first to sixth embodiments, the transmission direction of the medium guided by the guide is along a virtual tangent of the transfer rotating body that is orthogonal to the line connecting the center of the transfer rotating body and the center of the opposing rotating body.

[0016] The image forming system involved in the eighth method is the same as that in the image forming system described in the seventh method, wherein the media contact portion in the guide portion is planar when viewed from the side.

[0017] The image forming system involved in the 9th method is configured in any of the image forming systems described in the 1st to 8th methods as follows: when the guide moves toward the intermediate transfer body and away from the intermediate transfer body via the moving part, the angle between the virtual tangent of the transfer rotation body, which is orthogonal to the line connecting the center of the transfer rotation body and the center of the opposing rotation body, and the media contact portion in the guide is kept within ±4 degrees of the angle before the movement.

[0018] The image forming system according to the 10th embodiment, in any one of the 1st to 9th embodiments, includes: an adjustment roller, positioned upstream of the guide portion in the media transport direction, for adjusting the transport timing of the media; and a second moving portion, which moves the adjustment roller toward or away from the intermediate transfer body according to the moving position of the guide portion.

[0019] Invention Effects

[0020] According to the image forming system of the first method, compared with the case where only one end of the guide portion of the medium is moved laterally toward or away from the intermediate transfer body, the generation of image quality defects can be suppressed.

[0021] According to the image forming system of the second method, compared with the case where the position of the guide remains unchanged when the medium is a medium or film medium that is thicker than the specified thickness, the generation of image quality defects can be suppressed.

[0022] According to the image forming system involved in the third method, compared with the case where the position of the guide remains unchanged when the medium is a medium with a surface smoother than the specified smoothness, the generation of image quality defects caused by toner scattering can be suppressed.

[0023] According to the image forming system involved in the fourth method, compared with the case where the position of the guide remains unchanged by changing the secondary transfer voltage, the generation of image quality defects can be suppressed.

[0024] According to the image forming system involved in the fifth method, compared with the case where the position of the guide remains unchanged when the secondary transfer voltage is higher than the reference voltage, the generation of image quality defects can be suppressed.

[0025] According to the image forming system of the sixth method, compared with the case where the contact point between the medium guided by the guide and the intermediate transfer body is located in the circumferential direction of the intermediate transfer body, it is more downstream than the first transfer position and more upstream than the rotating component, scratches on the medium can be suppressed.

[0026] According to the image forming system of the seventh method, compared with the case where the transmission direction of the medium guided by the guide is the direction intersecting with the virtual tangent of the transfer rotating body, scratches on the medium can be suppressed, wherein the virtual tangent of the transfer rotating body is orthogonal to the line connecting the center of the transfer rotating body and the center of the opposing rotating body.

[0027] According to the image forming system involved in the eighth method, scratches on the media can be suppressed compared to the case where the media contact part in the guide is bent or folded.

[0028] According to the image forming system of the ninth method, compared with the case where the angle between the virtual tangent and the part of the guide that contacts the media changes when the guide moves toward the intermediate transfer body and away from the intermediate transfer body, scratches on the media can be suppressed.

[0029] According to the image forming system of the 10th method, compared with the case where the position of the position adjusting roller is fixed when the guide moves, scratches on the media can be suppressed. Attached Figure Description

[0030] The embodiments of the present invention will be described in detail with reference to the following figures.

[0031] Figure 1 This is a schematic diagram showing the structure of the image forming system according to the first embodiment as viewed from the front side;

[0032] Figure 2 This is a structural diagram showing the moving direction of the guide portion in the secondary transfer section of the image forming system according to the first embodiment;

[0033] Figure 3 This is a structural diagram showing the state in which the guide portion in the secondary transfer section of the image forming system according to the first embodiment is moved to a second position close to the intermediate transfer belt;

[0034] Figure 4 This is a structural diagram showing the moving direction of the guide portion in the secondary transfer section of the image forming system according to the second embodiment;

[0035] Figure 5 This is a structural diagram illustrating the positional relationship between the guide portion and the positioning roller in the secondary transfer section of the image forming system according to the second embodiment;

[0036] Figure 6 This is a structural diagram showing the moving direction of the guide portion in the secondary transfer section of the image forming system according to the third embodiment;

[0037] Figure 7 This is a structural diagram showing the state in which the guide portion in the secondary transfer section of the image forming system according to the third embodiment is moved to a second position close to the intermediate transfer belt;

[0038] Figure 8 It is a graph showing the relationship between the height of the guide section into which the paper enters and the white spot condition caused by pre-discharge in the image forming system according to the third embodiment;

[0039] Figure 9 This is a structural diagram showing the moving direction of the guide portion in the secondary transfer section of the image forming system according to the fourth embodiment;

[0040] Figure 10 This is a structural diagram showing the state in which the guide portion in the secondary transfer section of the image forming system according to the fourth embodiment is moved to a second position close to the intermediate transfer belt.

[0041] Symbol Explanation

[0042] 10 - Image forming system; 31 - Intermediate transfer belt (an example of an intermediate transfer body); 32B - Inner roller (an example of a transfer rotating body); 34 - Secondary transfer section; 54 - Positioning roller (an example of an adjusting roller); 56 - Guide section; 60 - Secondary transfer roller (an example of an opposing rotating body); 70 - Pre-roll roller (an example of a rotating component); 80 - Moving section; 102 - Plate-shaped section (an example of a guide section); 102A - Planar portion (an example of a media contact area); 10 2C - Upstream end, 104 - Plate-shaped part (an example of a guide part), 150 - Image forming system, 152 - Moving part, 200 - Image forming system, 202 - Guide part, 300 - Image forming system, 302 - Positioning roller (an example of an adjusting roller), 310 - Moving part (an example of a second moving part), CP1 - Contact point, CP2 - Contact point, L1 - Line, L2 - Virtual tangent, NT - Secondary transfer position, P - Paper (an example of a media). Detailed Implementation

[0043] The following describes a method for implementing the present invention. In the following description, the direction indicated by arrow H in the drawings is defined as the vertical direction, and the direction indicated by arrow W is defined as the horizontal direction and the width direction of the device.

[0044] [First Implementation]

[0045] The image forming system according to the first embodiment will be described below.

[0046] <Overall Structure of Image Forming System>

[0047] Figure 1 This is a schematic diagram showing the structure of the image forming system 10 according to the first embodiment, viewed from the front side. (See diagram below.) Figure 1 As shown, the image forming system 10 includes an image forming unit 12 that forms an image on paper P by electrophotography, a conveying device 50 for conveying paper P, and a control unit 90 that controls the operation of each part of the image forming system 10. Paper P is an example of a medium.

[0048] (Transmission device)

[0049] like Figure 1As shown, the conveying device 50 includes: a receiving section 51 for receiving paper P; and multiple conveying rollers 52 and 53 for conveying paper P from the receiving section 51 toward the secondary transfer position NT. Furthermore, the conveying device 50 has a guide section 56 disposed upstream of the secondary transfer position NT in the conveying direction of paper P, and a positioning roller 54 disposed further upstream of the guide section 56 in the conveying direction of paper P. The positioning roller 54 adjusts the timing of the conveying of paper P to the secondary transfer position NT. The guide section 56 guides paper P toward the secondary transfer position NT downstream of the positioning roller 54 in the conveying direction. Moreover, the conveying device 50 has a conveyor belt 58 for conveying paper P from the secondary transfer position NT to the fixing device 40 (described later).

[0050] (Image forming unit)

[0051] The image forming unit 12 includes: a toner image forming unit 20 for forming a toner image; a transfer device 30 for transferring the toner image formed by the toner image forming unit 20 onto a paper P; and a fixing device 40 for fixing the toner image transferred onto the paper P by heating and pressurizing it.

[0052] The system includes multiple toner image forming units 20 to form toner images for each color. For example, four toner image forming units 20 are provided for yellow (Y), magenta (M), cyan (C), and black (K). These toner image forming units 20 for each color are arranged in the order of yellow (Y), magenta (M), cyan (C), and black (K), from upstream to downstream in the transport direction of the intermediate transfer belt 31 (described later).

[0053] Figure 1 The (Y), (M), (C), and (K) symbols represent the constituent parts corresponding to the aforementioned colors. Additionally, in this specification, the parentheses around (Y), (M), (C), and (K) are sometimes omitted, and the symbols are simply written as Y, M, C, and K.

[0054] [Toner Image Forming Section]

[0055] Except for the toner used, the toner image forming units 20 for each color are basically constructed similarly. Specifically, each color toner image forming unit 20 includes a photosensitive drum 21, a charging device 22, an exposure device 23, a developing device 24, and a cleaning device 25. The photosensitive drum 21 has a photosensitive layer on its surface and rotates clockwise as indicated by the arrow. The charging device 22 charges the photosensitive drum 21. The exposure device 23 exposes the photosensitive drum 21, which is charged by the charging device 22, thereby forming an electrostatic latent image on the photosensitive drum 21. Furthermore, the developing device 24 develops the electrostatic latent image formed on the photosensitive drum 21 by the exposure device 23 to form a toner image. The cleaning device 25 includes a scraper 25A, which removes the toner remaining on the surface of the photosensitive drum 21 after the toner image is transferred to the transfer device 30. In addition, in Figure 1 In the toner image forming section 20 for each color, all the constituent parts are the same except for the toner, so the illustrations of (Y), (M), (C), and (K) are omitted.

[0056] The charge carrier 22, for example, causes the surface (photosensitive layer) of the photosensitive drum 21 to become negatively charged. The portion of the negatively charged surface of the photosensitive drum 21 exposed to exposure light L by the exposure device 23 becomes positively charged, thereby forming an electrostatic latent image on the surface of the photosensitive drum 21. Then, in the developing device 24, negatively charged toner is rubbed onto the positively charged electrostatic latent image, thereby developing the electrostatic latent image. Thus, a toner image is formed on the surface (outer peripheral surface) of the photosensitive drum 21. A scraper 25A contacts the surface of the photosensitive drum 21 and scrapes away the toner remaining on the surface of the photosensitive drum 21.

[0057] [Transfer device]

[0058] The transfer apparatus 30 includes an intermediate transfer belt 31, a primary transfer roller 33, and a secondary transfer section 34. The intermediate transfer belt 31 is an example of an intermediate transfer body. The transfer apparatus 30 overlays the toner images of each color photosensitive drum 21 onto the intermediate transfer belt 31 and performs a primary transfer. At the secondary transfer position NT, the overlaid toner images are then transferred a second time onto the paper P. The secondary transfer section 34 includes a secondary transfer belt 36.

[0059] like Figure 1 As shown, the intermediate transfer belt 31 is in a ring shape and its posture is determined by winding it around the drive roller 32D, tension application roller 32T, pre-roller 70, and inner roller 32B. The drive roller 32D, tension application roller 32T, pre-roller 70, and inner roller 32B are examples of multiple rollers and are in contact with the inner side of the ring-shaped intermediate transfer belt 31. The inner roller 32B is an example of a transfer rotating body. The pre-roller 70 is an example of a rotating component. As an example, the intermediate transfer belt 31 is positioned as a reverse obtuse-angled triangle that is longer in the width direction of the device when viewed from the front. In addition, other rollers for winding the intermediate transfer belt 31 may be provided.

[0060] Drive roller 32D, powered by a motor (not shown), causes intermediate transfer belt 31 to wrap in the direction of arrow A. By wrapping in the direction of arrow A, intermediate transfer belt 31 conveys the toner image transferred from the first transfer to the outer peripheral surface to the secondary transfer position NT. As an example, drive roller 32D is positioned upstream of the four primary transfer rollers 33 in the wrapping direction of intermediate transfer belt 31. Tension application roller 32T applies tension to intermediate transfer belt 31.

[0061] The pre-roller 70 is positioned downstream of the tension application roller 32T and upstream of the inner roller 32B in the circumferential direction of the intermediate transfer belt 31 at the primary transfer position T. The pre-roller 70 contacts the inner side of the intermediate transfer belt 31 upstream of the secondary transfer position NT. The pre-roller 70 contacts the intermediate transfer belt 31 outward in a straight line (not shown) relative to the tangent of the connecting tension application roller 32T and the tangent of the inner roller 32B (see reference). Figure 2 Therefore, at the position of the intermediate transfer belt 31 toward the secondary transfer position NT, the pre-roller 70 applies tension to the intermediate transfer belt 31, thereby stabilizing the circumferential movement of the intermediate transfer belt 31.

[0062] Furthermore, the inner roller 32B is the opposing roller to the secondary transfer roller 60 described later. As described above, the top of the obtuse angle side of the lower end of the intermediate transfer belt 31, which is formed in an obtuse triangular shape, is wound on the inner roller 32B. The upper edge of this intermediate transfer belt 31, which extends in the width direction of the device in the aforementioned manner, contacts the photosensitive drums 21 of each color from below.

[0063] A cleaning device 35 for removing residual toner from the intermediate transfer belt 31 is provided downstream of the secondary transfer position NT and upstream of the primary transfer position T(K) in the circumferential direction of the intermediate transfer belt 31. As an example, the cleaning device 35 includes a cleaning brush 35A, a scraper 35B, and a scraper blade 35C. The cleaning brush 35A removes toner from the surface of the intermediate transfer belt 31 by rotating while in contact with the surface. The scraper 35B contacts the intermediate transfer belt 31 and scrapes off the toner from its surface. The scraper blade 35C contacts the intermediate transfer belt 31 and scrapes off any toner from its surface that was not removed by the cleaning brush 35A and the scraper 35B.

[0064] like Figure 1As shown, the primary transfer roller 33 is a roller that transfers the toner image of each photosensitive drum 21 onto the intermediate transfer belt 31, and is disposed inside the intermediate transfer belt 31. Each primary transfer roller 33 is arranged opposite the photosensitive drum 21 of the corresponding color, sandwiching the intermediate transfer belt 31. Furthermore, a primary transfer voltage of opposite polarity to the toner is applied to the primary transfer roller 33 via a power supply unit (not shown). With the application of this primary transfer voltage, the toner image formed on the photosensitive drum 21 is transferred onto the intermediate transfer belt 31 at the primary transfer position T between the photosensitive drum 21 and the primary transfer roller 33.

[0065] like Figure 1 and Figure 2 As shown, the secondary transfer section 34 includes a secondary transfer belt 36, a secondary transfer roller 60 that can support the secondary transfer belt 36 in a surrounding manner, and a driven roller 61. The secondary transfer roller 60 is an example of an opposing rotating body. Furthermore, the secondary transfer section 34 includes an inner roller 32B that is opposed to the secondary transfer roller 60 via the intermediate transfer belt 31 and the secondary transfer belt 36, and a contact roller 64 that supplies power to the inner roller 32B by contacting the inner roller 32B (see reference). Figure 2 The power supply unit 66 is connected to the contact roller 64 (reference). Figure 2 As an example, the contact roller 64 rotates driven by the rotation of the inner roller 32B. Although not shown in the figure, the secondary transfer roller 60 is grounded. Furthermore, the secondary transfer section 34 is equipped with a cleaning device 62 for removing toner from the surface of the secondary transfer belt 36 (see reference). Figure 1 In the secondary transfer section 34, a secondary transfer voltage is applied to the inner roller 32B from the power supply device 66 via the contact roller 64, thereby forming a transfer electric field. Through this transfer electric field, the toner superimposed on the intermediate transfer belt 31 is transferred onto the paper P conveyed between the intermediate transfer belt 31 and the secondary transfer belt 36.

[0066] The secondary transfer belt 36 is in a loop and is wound around the secondary transfer roller 60 and the driven roller 61. The secondary transfer roller 60 is driven to rotate by a motor (not shown). The driven roller 61 is driven as the secondary transfer belt 36 moves around.

[0067] The secondary transfer roller 60 is configured to sandwich the intermediate transfer belt 31 and the secondary transfer belt 36 between itself and the inner roller 32B, with the secondary transfer belt 36 and the intermediate transfer belt 31 in contact with a predetermined load. This contact between the secondary transfer belt 36 and the intermediate transfer belt 31 constitutes the secondary transfer position NT. Paper P is supplied from the receiving section 51 to this secondary transfer position NT at a predetermined time. The secondary transfer belt 36 is rotated and driven by the secondary transfer roller 60 to move in the direction of arrow B.

[0068] As an example, the secondary transfer roller 60 is composed of a foaming roller that disperses conductive resin. As an example, the driven roller 61 is composed of a metal roller. As an example, the inner roller 32B has a structure that disperses conductive materials such as carbon on the foaming roller.

[0069] For example, when transferring the toner image from the surface of the intermediate transfer belt 31 onto the paper P, a negative voltage is applied to the inner roller 32B via the contact roller 64 through the power supply device 66. This creates a potential difference between the inner roller 32B and the secondary transfer roller 60. That is, by applying a negative voltage to the inner roller 32B, a secondary transfer voltage (a positive voltage) of opposite polarity to the toner is indirectly applied to the secondary transfer roller 60, which forms the opposing electrode of the inner roller 32B. Thus, a negative toner image is transferred from the intermediate transfer belt 31 to the paper P passing through the secondary transfer position NT. As an example, the secondary transfer voltage is determined based on the type of paper P and the width of the direction orthogonal to the transport direction of the paper P.

[0070] The cleaning device 62 is a scraper that contacts the secondary transfer belt 36 and removes the toner adhering to the secondary transfer belt 36.

[0071] [Fixing device]

[0072] like Figure 1 As shown, the fixing device 40 includes a heating roller 40A and a pressure roller 40B pressed against the heating roller 40A. Paper P with a toner image transferred onto it passes through the clamping part between the heating roller 40A and the pressure roller 40B, thereby fixing the toner image onto the paper P.

[0073] <The Actions of the Image Forming System>

[0074] Next, the operation of the image forming system 10 will be explained.

[0075] When the image forming system 10 begins operation, toner images of each color (Y), (M), (C), and (K) are formed on the surface of the photosensitive drum 21 through charging, exposure, and development processes in the toner image forming units 20. Specifically, the photosensitive drum 21 is charged by the charger 22 and exposed by the exposure device 23, thereby forming a latent image on the surface of the photosensitive drum 21. Furthermore, the latent image of the photosensitive drum 21 is developed by the toner through the development device 24. Thus, toner images of each color are formed on the surface of the photosensitive drum 21 in the toner image forming units 20.

[0076] In the image forming system 10, a transfer voltage is applied to the primary transfer rollers 33 of each color. Meanwhile, the drive roller 32D causes the intermediate transfer belt 31 to wrap around in the direction of arrow A. Thus, the toner images of each color formed on the photosensitive drums 21 of each color are superimposed on the intermediate transfer belt 31 for a single transfer.

[0077] On the other hand, the paper P contained in the receiving section 51 is conveyed to the secondary transfer position NT by the conveying device 50 in a manner that coincides with the arrival time of the areas in the intermediate transfer belt 31 where the toner images of each color have been transferred in the first stage. Then, by applying a secondary transfer voltage to the inner roller 32B, a transfer electric field is formed between the inner roller 32B and the secondary transfer roller 60, and the toner images of each color in the intermediate transfer belt 31 are retained and transferred onto the paper P.

[0078] Furthermore, the paper P, on which the toner images of each color are transferred, is conveyed toward the fixing device 40 via the conveying device 50. Then, via the fixing device 40, the toner images of each color are fixed on the paper P passing between the heating roller 40A and the pressure roller 40B, forming an image on the paper P. Thus, the image forming operation ends.

[0079] <Structure that moves the guide section of the image forming system>

[0080] Next, the structure that moves the guide section 56, which is the main part of the image forming system 10, will be described.

[0081] like Figure 2 and Figure 3 As shown, the image forming system 10 includes: a guide 56 that guides the paper P to the secondary transfer position NT; and a moving part 80 that moves the guide 56 toward or away from the intermediate transfer belt 31.

[0082] (Guidance Department)

[0083] like Figure 2 and Figure 3 As shown, the guide portion 56 includes a pair of plate-shaped portions 102 and 104 arranged at a distance from each other on both sides of the paper P through which it passes. One plate-shaped portion 102 is disposed on the side away from the intermediate transfer belt 31, and the other plate-shaped portion 104 is disposed on the side closer to the intermediate transfer belt 31. In the first embodiment, one plate-shaped portion 102 is disposed on the lower side in the vertical direction, and the other plate-shaped portion 104 is disposed on the upper side in the vertical direction. The paper P is guided to the secondary transfer position NT through the pair of plate-shaped portions 102 and 104.

[0084] As an example, the plate-shaped portion 102 includes a planar portion 102A and a bent portion 102B that bends away from the downstream end of the planar portion 102A in a direction away from the plate-shaped portion 104. The lower surface of the paper P can contact the planar portion 102A of the plate-shaped portion 102. The planar portion 102A of the plate-shaped portion 102 is an example of a media contact portion (i.e., a paper contact portion) in contact with the paper P. As an example, the plate-shaped portion 104 is planar, and the upper surface of the paper P can contact the plate-shaped portion 104. As an example, the planar portion 102A and the plate-shaped portion 104 of the plate-shaped portion 102 are arranged parallel to each other.

[0085] The planar portion 102A of the guide section 56, which serves as the paper contact area, is positioned in a direction intersecting the line L1 connecting the center of the inner roller 32B and the center of the secondary transfer roller 60. As an example, the planar portion 102A and the plate-shaped portion 104 of the plate-shaped portion 102 are inclined at an upward slope toward the secondary transfer position NT. For instance, the angle θ between the virtual tangent L2 of the inner roller 32B, which is orthogonal to line L1, and the planar portion 102A of the plate-shaped portion 102 and the virtual extension line L3 along the middle of the plate-shaped portion 104 is [not specified].

[0086] (Mobility Department)

[0087] like Figure 2 and Figure 3 As shown, the moving part 80 includes: a cam 82 that contacts the lower surface (the side opposite to the plate-shaped part 104) of the planar portion 102A of the plate-shaped part 102; and a motor 84 that rotates the shaft portion 83 of the cam 82. The drive of the motor 84 is controlled by the control part 90.

[0088] Depending on the type of paper P, the moving part 80 moves the entire planar portion 102A of the guide portion 56 relative to the intermediate transfer belt 31 while maintaining its orientation intersecting with line L1. As an example, a pair of plate-shaped portions 102, 104 are integrally supported by a frame (not shown). The moving part 80 moves the pair of plate-shaped portions 102, 104 integrally in the vertical direction (arrow D direction) by rotating the cam 82. Specifically, by rotating the cam 82, the smaller diameter portion of the cam 82 contacts the plate-shaped portion 102, thereby moving the guide portion 56 to a first position P1 (see reference) away from the intermediate transfer belt 31. Figure 2 Furthermore, by rotating the cam 82, the larger diameter portion of the cam 82 contacts the plate-shaped portion 102, thereby moving the guide portion 56 to a second position P2 near the intermediate transfer belt 31 (see reference). Figure 3 In the first embodiment, the moving part 80 moves the guide part 56 to a first position P1 on the lower side in the vertical direction and a second position P2 on the upper side in the vertical direction.

[0089] The type of paper P includes variations in paper thickness and smoothness. For example, when paper P is thicker than a specified thickness, the moving part 80 moves the entire planar portion 102A of the guide portion 56 closer to the intermediate transfer belt 31 compared to paper of the specified thickness. Furthermore, when a film medium replaces paper P, the moving part 80 can move the entire planar portion 102A of the guide portion 56 closer to the intermediate transfer belt 31 compared to paper of the specified thickness.

[0090] As an example, when the paper P is a paper P with a surface smoother than the specified smoothness, compared to the paper with the specified smoothness, the moving part 80 moves the entire planar portion 102A in the guide part 56 in a direction away from the intermediate transfer belt 31.

[0091] Furthermore, the moving part 80 moves the entire planar portion 102A in the guide part 56 toward or away from the intermediate transfer belt 31 according to the secondary transfer voltage.

[0092] As an example, when the secondary transfer voltage is higher than the reference voltage, compared to when the secondary transfer voltage is lower than the reference voltage, the moving part 80 moves the entire planar portion 102A in the guide part 56 towards the intermediate transfer belt 31. The reference voltage is preset, for example, according to the thickness of the paper P.

[0093] As an example, the moving part 80 moves the guide part 56 relative to the intermediate transfer belt 31 while maintaining an angle θ between the virtual tangent L2 of the inner roller 32B orthogonal to line L1 and the planar portion 102A of the plate-shaped portion 102 and the virtual extension line L3 along the middle of the plate-shaped portion 104. For example, when the guide part 56 moves towards the intermediate transfer belt 31 and away from the intermediate transfer belt 31, the angle between the virtual tangent L2 of the inner roller 32B orthogonal to line L1 and the planar portion 102A in the guide part 56 is the same. For example, it moves in a manner that keeps the angle between the virtual tangent L2 of the inner roller 32B orthogonal to line L1 and the planar portion 102A in the guide part 56 within ±4 degrees of the angle before the movement. That is, the same angle means moving in a manner that keeps the angle within ±4 degrees of the angle before the movement. The angle between the virtual tangent L2 of the inner roller 32B orthogonal to line L1 and the planar portion 102A of the guide portion 56 is preferably maintained within ±4 degrees of the angle before movement, more preferably within ±3 degrees, and even more preferably within ±2 degrees. In the first embodiment, the angle θ between the virtual tangent L2 of the inner roller 32B orthogonal to line L1 and the planar portion 102A of the plate-shaped portion 102 and the virtual extension line L3 along the middle of the plate-shaped portion 104 is set to be maintained within ±4 degrees of the angle before movement.

[0094] As an example, when the guide section 56 is moved to the first position P1, the paper P guided by the guide section 56 contacts the intermediate transfer belt 31 at the contact point CP1 (see reference). Figure 2 Furthermore, as an example, when the guide section 56 is moved to the second position P2, the paper P guided by the guide section 56 contacts the intermediate transfer belt 31 at the contact point CP2 (see reference). Figure 3 The contact points CP1 and CP2 between the paper P guided by the guide portion 56 and the intermediate transfer belt 31 are located downstream of the pre-roller 70 in the circumferential direction of the intermediate transfer belt 31. In the first embodiment, the contact points CP1 and CP2 between the paper P guided by the guide portion 56 and the intermediate transfer belt 31 are located between the contact portion of the pre-roller 70 and the inner roller 32B in the circumferential direction of the intermediate transfer belt 31.

[0095] <Problems with the Image Forming System in the Comparative Example>

[0096] Here, the problems with the image forming system of the comparative example will be explained.

[0097] Although the illustration is omitted, in the image forming system of the first comparative example, the toner image on the intermediate transfer belt is transferred onto the paper P at the secondary transfer position formed by the secondary transfer roller and the inner roller. In this method, if a gap occurs between the intermediate transfer belt and the paper P immediately before the secondary transfer position, a discharge occurs, resulting in image quality defects such as white spots. In particular, as the secondary transfer requires a high voltage medium, discharge is more likely to occur when using a medium such as paper or film that is thicker than the specified thickness.

[0098] In contrast, although the illustration is omitted, in the image forming system of the second comparative example, the guide portion is rotated about its upstream end in the secondary transfer position along the transport direction of the paper P. For example, by rotating the guide portion about its upstream end, the downstream end of the guide portion is rotated away from the intermediate transfer belt. As a result, the entry angle of the paper P towards the intermediate transfer belt is increased relative to before the guide portion is rotated, thereby suppressing discharge.

[0099] However, in the image forming system of the second comparative example, sometimes by rotating the guide section, the transportability of the thick paper P changes, and scratches are generated on the paper P by increasing the entry angle of the paper P towards the central transfer belt. Sometimes, the generation of scratches on the paper P becomes the cause of poor image quality (image quality defects).

[0100] Furthermore, sometimes by rotating the guide section around its upstream end, the downstream end of the guide section is rotated toward the intermediate transfer belt, and the gap between the paper P and the intermediate transfer belt becomes smaller, thereby causing the toner on the smooth paper to scatter.

[0101] Therefore, in the image forming system of the second comparative example, there is room for improvement in suppressing the generation of poor image quality (image quality defects).

[0102] <Functions and Effects>

[0103] Next, the function of the first embodiment will be explained.

[0104] The image forming system 10 of the first embodiment includes an annular intermediate transfer belt 31, an inner roller 32B, a secondary transfer roller 60, a guide section 56, and a moving section 80. The intermediate transfer belt 31 moves in the circumferential direction, conveying a toner image that has been transferred to the outer peripheral surface in the first transfer. While rotating, the inner roller 32B contacts the intermediate transfer belt 31, and at the secondary transfer position NT opposite to the intermediate transfer belt 31, the toner image of the intermediate transfer belt 31 is transferred onto the paper P. While rotating, the secondary transfer roller 60 clamps the intermediate transfer belt 31 and faces the inner roller 32B, forming a potential difference between the roller and the inner roller 32B. The guide section 56 is disposed upstream of the paper P in the conveying direction relative to the secondary transfer position NT, guiding the paper P to the secondary transfer position NT. Depending on the type of paper P, the moving part 80 moves the entire planar portion 102A in the guide part 56 towards or away from the intermediate transfer belt 31 while maintaining an orientation that intersects the line L1 connecting the center of the inner roller 32B and the center of the secondary transfer roller 60.

[0105] As described above, in the image forming system 10, depending on the type of paper P, the entire planar portion 102A in the guide portion 56 is moved towards or away from the intermediate transfer belt 31, thereby suppressing the generation of discharge. Furthermore, the entire planar portion 102A in the guide portion 56 is moved towards or away from the intermediate transfer belt 31 while maintaining its orientation intersecting with line L1. Therefore, compared to cases where the entry angle of paper P towards the intermediate transfer belt changes, the transport properties of thicker paper P are less likely to change, and scratches on the paper P are less likely to occur.

[0106] Therefore, in the image forming system 10, compared to the case where only one end of the guide portion of the medium is moved laterally toward or away from the intermediate transfer body, the generation of image quality defects can be suppressed.

[0107] Furthermore, in the image forming system 10, when the paper P is thicker than a predetermined thickness, the moving part 80 moves the entire planar portion 102A of the guide part 56 towards the intermediate transfer belt 31, compared to the predetermined thickness of the paper. Also, when a film medium is used instead of the paper P, the moving part 80 moves the entire planar portion 102A of the guide part 56 towards the intermediate transfer belt 31, compared to the predetermined thickness of the paper. Therefore, in the image forming system 10, compared to the case where the position of the guide part remains unchanged when the paper P is thicker than the predetermined thickness or when the film medium is used, the generation of image quality defects can be suppressed.

[0108] Furthermore, in the image forming system 10, when the paper P has a surface smoother than a specified smoothness, the moving part 80 moves the entire planar portion 102A in the guide part 56 away from the intermediate transfer belt 31, compared to paper with a specified smoothness. For example, in paper P with a smooth surface, if the distance between the paper P and the intermediate transfer belt 31 is small, the toner image of the intermediate transfer belt 31 rubs against the paper P, causing toner scattering. By increasing the distance between the paper P and the intermediate transfer belt 31, the toner image of the intermediate transfer belt 31 becomes less likely to rub against the paper P. Therefore, in the image forming system 10, compared to the case where the position of the guide part remains unchanged when the paper P has a surface smoother than a specified smoothness, the generation of image quality defects caused by toner scattering can be suppressed.

[0109] Furthermore, in the image forming system 10, the moving part 80 moves the entire planar portion 102A in the guide part 56 toward or away from the intermediate transfer belt according to the secondary transfer voltage applied to the inner roller 32B. Thus, the interval between the intermediate transfer belt 31 and the paper P can be adjusted according to the secondary transfer voltage applied to the inner roller 32B. Therefore, in the image forming system 10, compared to the case where the position of the guide part remains unchanged by changing the secondary transfer voltage, the generation of image quality defects can be suppressed.

[0110] Furthermore, in the image forming system 10, when the secondary transfer voltage is higher than the reference voltage, the moving part 80 moves the entire planar portion 102A in the guide part 56 towards the intermediate transfer belt 31, compared to when the secondary transfer voltage is lower than the reference voltage. For example, when the secondary transfer voltage is higher than the reference voltage, the gap between the intermediate transfer belt 31 and the paper P is reduced. Conversely, when the secondary transfer voltage is lower than the reference voltage, the gap between the intermediate transfer belt 31 and the paper P is increased. For example, when the thickness of the paper P or the film medium is thicker than a predetermined thickness, the secondary transfer voltage is usually higher than the reference voltage. When the secondary transfer voltage is higher than the reference voltage, pre-discharge is easily generated between the intermediate transfer belt 31 and the paper P. By reducing the gap between the intermediate transfer belt 31 and the paper P, pre-discharge becomes less likely to occur. Therefore, in the image forming system 10, compared to the case where the position of the guide part remains unchanged when the secondary transfer voltage is higher than the reference voltage, the generation of image quality defects can be suppressed.

[0111] Furthermore, the image forming system 10 includes a pre-roller 70, which contacts the inner side of the intermediate transfer belt 31 on a downstream side in the circumferential direction of the intermediate transfer belt 31 than the primary transfer position T and on an upstream side in the circumferential direction of the intermediate transfer belt 31 than the secondary transfer roller 60. Moreover, the contact points CP1 and CP2 between the paper P guided by the guide 56 and the intermediate transfer belt are located on a downstream side of the pre-roller 70 in the circumferential direction of the intermediate transfer belt 31. Therefore, at the upstream side of the secondary transfer position NT, the paper P can be conveyed without bending as much as possible, thus reducing the likelihood of bending of the paper P. Therefore, in the image forming system 10, compared to the case where the contact points between the paper P guided by the guide and the intermediate transfer belt are located on a downstream side in the circumferential direction of the intermediate transfer belt and on an upstream side of the pre-roller, scratches on the paper P can be suppressed.

[0112] Furthermore, in the image forming system 10, when the guide portion 56 moves towards and away from the intermediate transfer belt 31, it moves in such a manner that the angle between the virtual tangent L2 of the inner roller 32B, which is orthogonal to line L1, and the planar portion 102A in the guide portion 56 remains within ±4 degrees of the angle before the movement. As a result, the entry angle of the paper P towards the intermediate transfer belt 31 does not change significantly, the conveying properties of the paper P are less likely to change, and the paper P is less likely to bend. Therefore, in the image forming system 10, compared to the case where the angle between the virtual tangent and the contact portion of the paper in the guide portion changes when the guide portion moves towards and away from the intermediate transfer belt, scratches on the paper P can be suppressed.

[0113] [Second Implementation]

[0114] Next, the image forming system of the second embodiment will be described. Furthermore, components identical to those in the first embodiment described above will be labeled with the same numbers, and their descriptions will be omitted.

[0115] like Figure 4 As shown, in the image forming system 150 of the second embodiment, the range of movement of the guide portion 56, which is moved by the moving portion 152, is different from that of the image forming system 10 of the first embodiment.

[0116] The moving part 152 includes: a cam 154 that contacts the lower surface (the side opposite to the plate-shaped portion 104) of the planar portion 102A of the plate-shaped portion 102; and a motor 156 that rotates the shaft portion 155 of the cam 154. The moving part 152 moves the guide portion 56 toward or away from the intermediate transfer belt 31 by the rotation of the cam 154.

[0117] Depending on the type of paper P, the moving part 152 moves the entire planar portion 102A of the guide portion 56 towards or away from the intermediate transfer belt 31 while maintaining its orientation intersecting with line L1. As an example, the moving part 152 moves the guide portion 56 in the vertical direction (arrow E direction) by rotating the cam 154, thereby moving it to position 1 P161, position 2 P162, and position 3 P163. Position 1 P161 is a reference position in the vertical direction. Position 2 P162 is a position higher (in the +H direction) than position 1 P161 and closer to the intermediate transfer belt 31. Position 3 P163 is a position lower (in the -H direction) than position 1 P161 and farther away from the intermediate transfer belt 31.

[0118] like Figure 5 As shown, at position P161, the upstream end 102C of the planar portion 102A of the plate-shaped portion 102 in the guide portion 56 is positioned on a line L5 orthogonal to the line L4 connecting the centers of the upper and lower positioning rollers 54. The planar portion 102A is the portion that contacts the paper P. The line L4 connecting the centers of the upper and lower positioning rollers 54 is a tangent to the contact portion of the upper and lower positioning rollers 54.

[0119] In addition, Figure 5 In the diagram, double-dotted lines indicate undesirable positions of the guide portion 56 in the vertical direction. If the guide portion 56 moves too far upwards and downwards, the paper P guided by the guide portion 56 will contact the intermediate transfer belt 31 on the pre-roller 70, which is not preferable. Furthermore, if the guide portion 56 moves too far downwards and downwards, the paper P guided by the guide portion 56 will contact the secondary transfer belt 36 on the secondary transfer roller 60, which is also not preferable. The other structures of the image forming system 150 are the same as those of the image forming system 10 in the first embodiment.

[0120] In the image forming system 150 of the second embodiment, the same function and effect can be obtained by using the same structure as the image forming system 10 of the first embodiment.

[0121] [Third Implementation]

[0122] Next, the image forming system of the third embodiment will be described. Furthermore, components identical to those in the first and second embodiments described above will be labeled with the same numbers, and their descriptions will be omitted.

[0123] like Figure 6 As shown, in the image forming system 200 of the third embodiment, the tilt angle of the guide portion 202 relative to the horizontal direction is different from that of the image forming system 10 of the first embodiment.

[0124] The guide section 202 includes a pair of plate-shaped portions 102 and 104. The planar portion 102A of the plate-shaped portion 102 in the guide section 202 is arranged in a direction (e.g., a 90-degree direction) that intersects the line L1 connecting the center of the inner roller 32B and the center of the secondary transfer roller 60. That is, the planar portion 102A of the plate-shaped portion 102 in the guide section 202 is arranged along the virtual tangent L2 of the inner roller 32B, which is orthogonal to the line L1 connecting the center of the inner roller 32B and the center of the secondary transfer roller 60.

[0125] The moving part 80 includes: a cam 82 that contacts the lower surface (the side opposite to the plate-shaped part 104) of the planar portion 102A of the plate-shaped part 102; and a motor 84 that rotates the shaft 83 of the cam 82. Depending on the type of paper P, the moving part 80 moves the entire planar portion 102A in the guide part 56 relative to the intermediate transfer belt 31 while maintaining an orientation that intersects (for example, at a 90-degree angle) with the line L1 connecting the center of the inner roller 32B and the center of the secondary transfer roller 60. In other words, the moving part 80 moves the entire planar portion 102A in the guide part 56 relative to the intermediate transfer belt 31 while maintaining an orientation along the direction of the virtual tangent L2 of the inner roller 32B, which is orthogonal to the line L1 connecting the center of the inner roller 32B and the center of the secondary transfer roller 60.

[0126] As an example, the paper P guided by the guide section 202 is conveyed in a direction along the virtual tangent L2 of the inner roller 32B, which is orthogonal to the line L1 connecting the center of the inner roller 32B and the center of the secondary transfer roller 60. The planar portion 102A, which is an example of the media contact portion of the plate-shaped portion 102 in the guide section 202, is planar when viewed from the side.

[0127] As an example, the moving part 80 moves the guide part 202 in the vertical direction (arrow F direction) by rotating the cam 82. The moving part 80 moves the guide part 202 to a first position P211 (reference) away from the intermediate transfer belt 31 by contacting the smaller diameter portion of the cam 82 with the plate-shaped part 102. Figure 6 The moving part 80 moves the guide part 202 to a second position P212 (reference) closer to the intermediate transfer belt 31 by bringing the larger diameter portion of the cam 82 into contact with the plate-shaped part 102. Figure 7 The image forming system 200 moves to a first position P211 on the lower side in the vertical direction and a second position P212 on the upper side in the vertical direction. Furthermore, the other structures of the image forming system 200 are the same as those of the image forming system 10 in the first embodiment.

[0128] In the image forming system 200 of the third embodiment, in addition to the functions and effects based on the same structure as the image forming system 10 of the first embodiment, the following functions and effects can also be obtained.

[0129] In the image forming system 200, the paper P guided by the guide 202 is conveyed in a direction along the virtual tangent L2 of the secondary transfer roller 60, which is orthogonal to the line L1 connecting the center of the inner roller 32B and the center of the secondary transfer roller 60. Therefore, when the paper P guided by the guide 202 is conveyed to the secondary transfer position NT, the paper P is conveyed in a nearly straight shape with almost no bending. Thus, the paper P is less prone to bending. Therefore, in the image forming system 200, compared to the case where the conveying direction of the paper P guided by the guide intersects with the virtual tangent of the secondary transfer roller, which is orthogonal to the line connecting the center of the opposing roller and the center of the secondary transfer roller, scratches on the paper P can be suppressed.

[0130] Furthermore, in the image forming system 200, the planar portion 102A of the plate-shaped portion 102 that the paper P contacts in the guide portion 202 is planar when viewed from the side. Therefore, in the image forming system 200, compared to the case where the media contact portion in the guide portion is bent or folded, scratches on the paper P can be suppressed.

[0131] Figure 8 This is a graph showing the relationship between the height of the guide section 202 when the paper P enters the secondary transfer position NT and the white spot formation caused by pre-discharge immediately preceding the secondary transfer position NT. Figure 8 The horizontal axis of the graph shows how much the height of the guide section 202 has increased from its reference height "0". Furthermore, Figure 8The vertical axis of the graph shown represents the staged formation of white spots caused by pre-discharge, with numerical values ​​indicating that the formation of white spots worsens as the value increases. Furthermore, the incident angle of the intermediate transfer belt 31 relative to the secondary transfer position NT in the horizontal direction is 6 degrees, and the processing speed is 1000 mm / s. Also, the paper P uses paper with a specified basis weight (500 gsm). Figure 8 As shown, it can be seen that by increasing the height of the guide section 202 in the vertical direction, the formation of white spots caused by pre-discharge is being improved. Therefore, it can be seen that by reducing the gap between the paper P and the intermediate transfer belt 31, the formation of white spots caused by pre-discharge is being improved.

[0132] [Fourth Implementation]

[0133] Next, the image forming system of the fourth embodiment will be described. Furthermore, components identical to those in the first to third embodiments described above will be labeled with the same numbers, and their descriptions will be omitted.

[0134] Image forming system 150 in contrast to the second embodiment (reference) Figure 4 The position of the positioning roller 54 is fixed, but the difference is that, for example... Figure 9 and Figure 10 As shown, in the image forming system 300 of the fourth embodiment, the position of the positioning roller 302 is moved. The positioning roller 302 is an example of an adjusting roller. The positioning roller 302 is positioned upstream of the guide portion 56 in the conveying direction of the paper P, and adjusts the conveying time of the paper P conveyed to the secondary transfer position NT. The positioning roller 302 consists of a pair of upper and lower rollers.

[0135] The image forming system 300 includes a moving part 310 that moves the guide part 56 and the positioning roller 302 as a unit towards or away from the intermediate transfer belt 31. Although not shown in the figure, the image forming system 300 includes a support frame that integrally supports the guide part 56 and the positioning roller 302. The positioning roller 302 is rotatably supported on the support frame. The moving part 310 includes a cam 312 that contacts the support frame near the lower surface of the planar portion 102A of the plate-shaped portion 102; and a motor 156 that rotates the shaft portion 313 of the cam 312. As an example, the moving part 310 moves the support frame by rotating the cam 312, thereby moving the guide part 56 and the positioning roller 302 as a unit in the vertical direction (arrow E direction). Thus, the moving part 310 moves the positioning roller 302 towards or away from the intermediate transfer belt 31 according to the moving position of the guide part 56. As an example, the moving part 310 moves the positioning roller 302 in the vertical direction (arrow E direction) by the same distance as the guide part 56. The moving part 310 is an example of a second moving part that also acts as a moving part for moving the guide part 56.

[0136] Specifically, the moving part 310 moves the guide part 56 to three positions in the vertical direction (arrow E direction): position 1 P161, position 2 P162, and position 3 P163. Position 1 P161 is the middle reference position in the vertical direction. Position 2 P162 is higher (in the +H direction) than position 1 P161 and closer to the middle transfer belt 31. Position 3 P163 is lower (in the -H direction) than position 1 P161 and farther away from the middle transfer belt 31.

[0137] At this time, the moving part 310, corresponding to the moving position of the guide part 56, moves the positioning roller 302 to the first position P321, the second position P322, and the third position P323 in the vertical direction (arrow E direction). The first position P321 is the middle reference position in the vertical direction. The second position P322 is a position that is higher (in the +H direction) than the first position P321 and closer to the intermediate transfer belt 31. The third position P323 is a position that is lower (in the -H direction) than the first position P321 and farther away from the intermediate transfer belt 31. In addition, the other structures of the image forming system 300 are the same as those of the image forming system 150 of the second embodiment.

[0138] In the image forming system 300 of the fourth embodiment, in addition to the functions and effects based on the same structure as the image forming system 10 of the first embodiment, the following functions and effects can also be obtained.

[0139] The image forming system 300 includes a positioning roller 302 and a moving part 310. The moving part 310 moves the positioning roller 302 closer to or further away from the intermediate transfer belt 31 according to the moving position of the guide part 56. Therefore, when the paper P conveyed by the positioning roller 302 is guided by the guide part 56 to the secondary transfer position NT, the paper P becomes less prone to bending, and folding or other damage to the paper P is less likely to occur. Thus, in the image forming system 300, compared to the case where the position of the adjusting roller is fixed while the guide part moves, scratches on the paper P can be suppressed.

[0140] [Additional Explanation]

[0141] In the image forming systems 10, 150, 200, and 300 of the first to fourth embodiments, the guide portions 56 and 202 are composed of a pair of plate-shaped portions 102 and 104, where the plate-shaped portion 104 is planar and the main portion of the plate-shaped portion 102 is planar. However, the present invention is not limited to this structure. For example, the guide portion may be composed of a plate-shaped portion bent at the middle portion in the paper transport direction. Furthermore, for example, the guide portion may not be a pair of plate-shaped portions, but may be composed of a single plate-shaped portion.

[0142] Furthermore, in the image forming systems 10, 150, 200, and 300 of the first to fourth embodiments, a secondary transfer voltage is applied to the inner roller 32B, but the present invention is not limited to this structure. For example, it may be a structure in which the secondary transfer voltage is applied to the secondary transfer roller 60.

[0143] Furthermore, in the image forming system 300 of the fourth embodiment, the moving part 310 moves the guide part 56 and the positioning roller 302 as a single unit, but the present invention is not limited to this structure. For example, a moving part that moves the guide part 56 and a second moving part that moves the positioning roller 302 may be provided separately.

[0144] In the image forming systems 10, 150, 200, and 300 of the first to fourth embodiments, the paper P is conveyed horizontally at the secondary transfer position NT, causing the toner image of the intermediate transfer belt 31 to be transferred onto the paper P. However, the present invention is not limited to this structure. For example, in the image forming system, the structure could be such that the paper P is conveyed vertically at the secondary transfer position NT, and the toner image of the intermediate transfer belt 31 is transferred onto the paper P. In this case, any structure with a moving part is acceptable, which, depending on the type of paper P, moves the entire media contact portion in the guide portion towards or away from the intermediate transfer belt while maintaining an orientation that intersects the line connecting the center of the transfer rotating body and the center of the opposing rotating body.

[0145] In the image forming systems 10, 150, 200, and 300 of the first to fourth embodiments, paper P is used, but a medium such as a film can also be used instead of paper P.

[0146] Furthermore, while specific embodiments of the present invention have been described in detail, the present invention is not limited to these embodiments. Various other embodiments can be adopted within the scope of the present invention, which will be apparent to those skilled in the art.

[0147] [Postscript] (1)

[0149] An image forming system having:

[0150] An annular intermediate transfer body, wound on multiple rollers and moving along the circumferential direction, transfers the toner image onto the outer peripheral surface in one transfer.

[0151] The transfer rotating body rotates while contacting the intermediate transfer body, and at the secondary transfer position opposite to the intermediate transfer body, it transfers the toner image of the intermediate transfer body onto the media.

[0152] The rotating body is positioned opposite the intermediate transfer body while rotating, and a potential difference is formed between the intermediate transfer body and the transfer rotating body.

[0153] The guide unit is positioned upstream of the media transport direction relative to the secondary transfer position, and guides the media to the secondary transfer position; and

[0154] The moving part, depending on the type of media, moves the entire media contact portion in the guide part towards or away from the intermediate transfer body while maintaining an orientation that intersects the line connecting the center of the transfer rotating body and the center of the opposing rotating body. (2)

[0156] According to the image forming system described in (1), wherein,

[0157] When the medium is a medium or film medium that is thicker than the specified thickness, the moving part moves the entire medium contact portion in the guide part toward the intermediate transfer body, relative to the specified thickness of the medium. (3)

[0159] According to the image forming system described in (1) or (2), wherein,

[0160] When the medium is a medium with a surface smoother than a specified smoothness, compared to a medium with a specified smoothness, the moving part causes the entire medium contact portion in the guide part to move away from the intermediate transfer body. (4)

[0162] The image forming system according to any one of (1) to (3), wherein,

[0163] The moving part moves the entire media contact portion in the guide part toward or away from the intermediate transfer body according to the secondary transfer voltage applied to the transfer rotating body or the opposing rotating body. (5)

[0165] According to the image forming system described in (4), wherein,

[0166] When the secondary transfer voltage is higher than the reference voltage, compared to when the secondary transfer voltage is lower than the reference voltage, the moving part causes the entire media contact portion in the guide part to move closer to the intermediate transfer body. (6)

[0168] The image forming system according to any one of (1) to (5) comprises:

[0169] The rotating component contacts the inner side of the intermediate transfer body at a position further downstream in the circumferential direction than the primary transfer position where the toner image is transferred onto the intermediate transfer body, and further upstream in the circumferential direction than the opposing rotating component.

[0170] The contact point between the medium guided by the guide and the intermediate transfer body is located on the downstream side of the intermediate transfer body in the circumferential direction, compared to the rotating component. (7)

[0172] The image forming system according to any one of (1) to (6), wherein,

[0173] The transmission direction of the medium guided by the guide is along the virtual tangent of the transfer rotating body, which is orthogonal to the line connecting the center of the transfer rotating body and the center of the opposing rotating body. (8)

[0175] According to the image forming system described in (7), wherein,

[0176] The media contact portion in the guide section is planar when viewed from the side. (9)

[0178] The image forming system according to any one of (1) to (8) is configured as follows:

[0179] When the guide moves toward the intermediate transfer body and away from the intermediate transfer body via the moving part, it moves in such a way that the angle between the virtual tangent of the transfer rotation body, which is orthogonal to the line connecting the center of the transfer rotation body and the center of the opposing rotation body, and the media contact portion in the guide remains within ±4 degrees of the angle before the movement. (10)

[0181] The image forming system according to any one of (1) to (9) has:

[0182] An adjusting roller, positioned upstream of the guide section in the media conveying direction, adjusts the media conveying timing; and

[0183] The second moving part moves the adjusting roller toward or away from the intermediate transfer body according to the moving position of the guide part.

[0184] According to the image forming system involved in (1), compared with the case where only one end of the guide portion of the medium is moved laterally toward or away from the intermediate transfer body, the generation of image quality defects can be suppressed.

[0185] According to the image forming system involved in (2), compared with the case where the position of the guide remains unchanged when the medium is a medium or film medium that is thicker than the specified thickness, the generation of image quality defects can be suppressed.

[0186] According to the image forming system involved in (3), compared with the case where the position of the guide remains unchanged when the medium is a medium with a surface smoother than the specified smoothness, the generation of image quality defects caused by toner scattering can be suppressed.

[0187] According to the image forming system involved in (4), compared with the case where the position of the guide remains unchanged by changing the secondary transfer voltage, the generation of image quality defects can be suppressed.

[0188] According to the image forming system involved in (5), compared with the case where the position of the guide remains unchanged when the secondary transfer voltage is higher than the reference voltage, the generation of image quality defects can be suppressed.

[0189] According to the image forming system involved in (6), compared with the case where the contact point between the medium guided by the guide and the intermediate transfer body is located in the circumferential direction of the intermediate transfer body, it is more downstream than the first transfer position and more upstream than the rotating component, scratches on the medium can be suppressed.

[0190] According to the image forming system involved in (7), compared with the case where the transmission direction of the medium guided by the guide is the direction that intersects with the virtual tangent of the transfer rotating body, scratches on the medium can be suppressed, wherein the virtual tangent of the transfer rotating body is orthogonal to the line connecting the center of the transfer rotating body and the center of the opposing rotating body.

[0191] According to the image forming system involved in (8), scratches on the media can be suppressed compared to the case where the media contact part in the guide is bent or folded.

[0192] According to the image forming system involved in (9), compared with the case where the angle between the virtual tangent and the part in the guide that contacts the media changes when the guide moves toward the intermediate transfer body and away from the intermediate transfer body, scratches on the media can be suppressed.

[0193] According to the image forming system involved in (10), compared with the case where the position of the position adjustment roller is fixed when the guide moves, scratches on the media can be suppressed.

[0194] The embodiments of the present invention described above are provided for illustrative purposes. Furthermore, these embodiments do not encompass the entirety of the invention, nor do they limit the invention to the disclosed methods. It will be apparent to those skilled in the art that various modifications and variations will be readily understood. These embodiments were chosen and described to most readily explain the principles and applications of the invention. Thus, those skilled in the art can understand the invention through various modifications that are assumed to be optimized for specific uses of various embodiments. The scope of the invention is defined by the foregoing claims and their equivalents.

Claims

1. An image forming system, comprising: An annular intermediate transfer body, wound on multiple rollers and moving along the circumferential direction, transfers the toner image onto the outer peripheral surface in one transfer. The transfer rotating body rotates while contacting the intermediate transfer body, and at the secondary transfer position opposite to the intermediate transfer body, it transfers the toner image of the intermediate transfer body onto the media. The rotating body is positioned opposite the intermediate transfer body while rotating, and a potential difference is formed between the intermediate transfer body and the transfer rotating body. The guide unit is positioned upstream of the media transport direction relative to the secondary transfer position, and guides the media to the secondary transfer position; and The moving part, depending on the type of media, moves the entire media contact portion in the guide part towards or away from the intermediate transfer body while maintaining an orientation that intersects the line connecting the center of the transfer rotating body and the center of the opposing rotating body.

2. The image forming system according to claim 1, wherein, When the medium is a medium or film medium that is thicker than the specified thickness, the moving part moves the entire medium contact portion in the guide part toward the intermediate transfer body, relative to the specified thickness of the medium.

3. The image forming system according to claim 1 or 2, wherein, When the medium is a medium with a surface smoother than a specified smoothness, compared to a medium with a specified smoothness, the moving part causes the entire medium contact portion in the guide part to move away from the intermediate transfer body.

4. The image forming system according to any one of claims 1 to 3, wherein, The moving part moves the entire media contact portion in the guide part toward or away from the intermediate transfer body according to the secondary transfer voltage applied to the transfer rotating body or the opposing rotating body.

5. The image forming system according to claim 4, wherein, When the secondary transfer voltage is higher than the reference voltage, compared to when the secondary transfer voltage is lower than the reference voltage, the moving part causes the entire media contact portion in the guide part to move closer to the intermediate transfer body.

6. The image forming system according to any one of claims 1 to 5, comprising: The rotating component contacts the inner side of the intermediate transfer body at a position further downstream in the circumferential direction than the primary transfer position where the toner image is transferred onto the intermediate transfer body, and further upstream in the circumferential direction than the opposing rotating component. The contact point between the medium guided by the guide and the intermediate transfer body is located on the downstream side of the intermediate transfer body in the circumferential direction, compared to the rotating component.

7. The image forming system according to any one of claims 1 to 6, wherein, The transmission direction of the medium guided by the guide is along the virtual tangent of the transfer rotating body, which is orthogonal to the line connecting the center of the transfer rotating body and the center of the opposing rotating body.

8. The image forming system according to claim 7, wherein, The media contact portion in the guide section is planar when viewed from the side.

9. The image forming system according to any one of claims 1 to 8, wherein it is configured as follows: When the guide moves toward the intermediate transfer body and away from the intermediate transfer body via the moving part, it moves in such a way that the angle between the virtual tangent of the transfer rotation body, which is orthogonal to the line connecting the center of the transfer rotation body and the center of the opposing rotation body, and the media contact portion in the guide remains within ±4 degrees of the angle before the movement.

10. The image forming system according to any one of claims 1 to 9, comprising: An adjusting roller, positioned upstream of the guide section in the media conveying direction, adjusts the media conveying timing; and The second moving part moves the adjusting roller toward or away from the intermediate transfer body according to the moving position of the guide part.

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