JP2013160922A - Image forming apparatus - Google Patents

Abstract

Performance that emphasizes image quality and paper transportability can be improved.
An image forming apparatus includes an intermediate transfer belt, a secondary transfer unit, and a peeling member. The intermediate transfer belt 31 is rotatable in a predetermined direction, and a toner image is primarily transferred. The secondary transfer unit 40 secondarily transfers the toner image to the sheet conveyed through the secondary transfer area 92. The peeling member 71 peels the sheet from the intermediate transfer belt 31. In the rotational direction 91 of the intermediate transfer belt 31, the peeling member 71 is intermediate between a predetermined first peeling position in pressure contact with the intermediate transfer belt 31 on the downstream side of the secondary transfer region 92 and downstream of the first peeling position. It is configured to be movable between a predetermined second peeling position in pressure contact with the transfer belt 31.
[Selection] Figure 3

Description

  The present invention relates to an image forming apparatus including a peeling member that peels a sheet from an intermediate transfer belt.

  The intermediate transfer type image forming apparatus is configured to primarily transfer a toner image formed on the surface of an image carrier to an intermediate transfer belt, and secondarily transfer the toner image from the intermediate transfer belt to a sheet. Some intermediate transfer type image forming apparatuses include a peeling member for peeling the paper from the intermediate transfer belt in order to prevent paper conveyance failure due to the paper being wound around the intermediate transfer belt after the secondary transfer. (For example, refer to Patent Document 1).

  In the image forming apparatus described in Patent Document 1, the peeling member is configured to be movable in a direction perpendicular to the paper according to the thickness of the paper. The peeling member of the image forming apparatus described in Patent Document 1 is configured to reduce the electrostatic attraction force of the paper to the intermediate transfer belt by discharging the paper, but is in pressure contact with the intermediate transfer belt. Also in the conventional image forming apparatus provided with the above-described peeling member, the peeling member is disposed in the vicinity of the downstream side of the secondary transfer region in the paper transport direction. As a result, even if the paper is wound around the intermediate transfer belt, the peeling member peels off the paper from the intermediate transfer belt immediately after the secondary transfer, so that the paper is conveyed to the fixing device without causing paper conveyance failure. For this reason, the paper transportability is improved.

JP 2006-251664 A

  However, in the conventional image forming apparatus, the toner remaining on the intermediate transfer belt after the secondary transfer is scraped off by the peeling member, and the paper may be soiled by the toner. For this reason, the image quality may deteriorate.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus capable of improving performance, which is more important among image quality and paper transportability.

  The image forming apparatus of the present invention includes an image forming unit, an intermediate transfer belt, a secondary transfer unit, and a peeling member. The image forming unit includes an image carrier on which a toner image is formed. The intermediate transfer belt is stretched by a plurality of stretching rollers and is rotatable in a predetermined direction, and a toner image formed on the image carrier is primarily transferred. The secondary transfer unit is disposed in pressure contact with the intermediate transfer belt, and secondarily transfers the toner image transferred to the intermediate transfer belt onto a sheet conveyed through a pressure contact portion between the secondary transfer unit and the intermediate transfer belt. The peeling member peels the sheet from the intermediate transfer belt. The peeling member has a predetermined first peeling position in pressure contact with the intermediate transfer belt on the downstream side of the press contact portion in the rotation direction of the intermediate transfer belt, and a predetermined pressure contact with the intermediate transfer belt in the downstream side with respect to the first peeling position. It is configured to be movable between the second peeling position.

  In this configuration, when importance is attached to the sheet transportability, the peeling member is disposed at the first peeling position manually or by a control system. By disposing the peeling member at the first peeling position, even if the paper is wound around the intermediate transfer belt, the peeling member peels off the paper from the intermediate transfer belt immediately after the secondary transfer, so that the paper conveyance failure does not occur. The paper is conveyed. For this reason, paper conveyance property can be improved. On the other hand, when importance is attached to the image quality, the peeling member is disposed at the second peeling position manually or by a control system. By disposing the peeling member at the second peeling position, even if the toner remaining on the intermediate transfer belt after the secondary transfer is scraped off by the peeling member, the second peeling position is closer to the pressure contact portion than the first peeling position. Since they are separated from each other, the possibility that toner adheres to the paper is reduced. For this reason, the image quality can be improved.

  In the above configuration, when the peeling member moving mechanism unit that moves the peeling member between the first peeling position and the second peeling position, the operation unit that receives the setting operation of the image quality mode, and the high image quality mode are set. And a controller that places the peeling member at the second peeling position.

  In this configuration, when the high image quality mode is set, the separation member is arranged at the second separation position by the control unit controlling the separation member moving mechanism unit without manually moving the separation member. For this reason, it is possible to improve the performance that is more important among image quality and paper transportability with better operability.

  In addition, when the normal image quality mode is set, the control unit places the peeling member at the second peeling position when the paper is thick paper, and the first peeling member when the paper is plain paper. It can be configured to be placed in position.

  In this configuration, when the paper is a thick paper, the paper can be peeled off from the intermediate transfer belt due to the rigidity of the paper, so that the paper conveyance failure does not occur even when the peeling member is disposed at the second peeling position. For this reason, even when high image quality is not required, when the paper is thick paper, the performance of both the image quality and the paper transportability can be improved by disposing the peeling member at the second peeling position. When high image quality is not required and the paper is plain paper, paper conveyance performance is emphasized, and the peeling member is disposed at the first peeling position. As a result, even if the paper is wound around the intermediate transfer belt, the peeling member peels off the paper from the intermediate transfer belt immediately after the secondary transfer, so that the paper is conveyed without causing paper conveyance failure.

  Further, a peeling member moving mechanism that moves the peeling member between the first peeling position and the second peeling position, and a control unit that places the peeling member at the second peeling position when the paper is cardboard, It can comprise so that it may be provided.

  In this configuration, regardless of the image quality mode, when the paper is a thick paper, the control unit controls the peeling member moving mechanism to place the peeling member at the second peeling position. When the paper is a thick paper, it can be peeled off from the intermediate transfer belt due to the rigidity of the paper, so that both the image quality and the paper transportability can be improved.

  In addition, a thickness detection unit that detects the thickness of the paper and outputs the thickness information to the control unit is further provided, and the control unit is configured to determine an arrangement position of the peeling member based on the thickness information. Can do.

  In this configuration, since the thickness of the paper is detected by the thickness detection unit, the user does not need to perform an input operation and the operability is improved. Further, it is not necessary to perform an input operation, and the thickness detection unit detects the thickness of the sheet, so that the thickness information can be accurately acquired.

  Furthermore, it can comprise so that the position detection part which detects the position of a peeling member and outputs positional information and the notification part which notifies the position of a peeling member based on position information can be provided.

  In this configuration, since the position of the peeling member is notified by the position detection unit, workability is improved when the peeling member is moved manually. In addition, when the movement of the peeling member is performed by the control system, it can be confirmed whether or not the movement of the peeling member has been accurately performed.

  Moreover, the position detection part which detects the position of a peeling member and outputs position information is further provided, and a control part can be comprised so that the peeling member moving mechanism part may be controlled based on position information.

  In this configuration, the movement control of the peeling member can be accurately executed based on the position information output from the position detection unit.

  According to the present invention, it is possible to improve performance that places more importance on image quality and paper transportability.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. FIG. 6 is an enlarged view of a peripheral portion of a secondary transfer region showing a state where a peeling member is disposed at a first peeling position. It is an enlarged view of the peripheral part of the secondary transfer area showing the state where the peeling member is arranged at the second peeling position. It is a figure which shows the relationship between the position of a peeling member, and various performance. 1 is a block diagram showing a schematic electrical configuration of an image forming apparatus. It is a flowchart which shows 1st Example of the process sequence of a control part. It is a flowchart which shows 2nd Example of the process sequence of a control part. It is a flowchart which shows 3rd Example of the process sequence of a control part. It is a flowchart which shows 4th Example of the process sequence of a control part. It is a flowchart which shows 5th Example of the process sequence of a control part. It is a figure which shows the position of the peeling member on various conditions in 5th Example.

  Embodiments of the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, the image forming apparatus 10 operates in an image forming mode of either a monochrome image forming mode or a full color image forming mode, and forms a single color or a multicolor image on a sheet based on image data. Examples of paper include plain paper and cardboard. The image forming apparatus 10 includes a plurality of image forming units 20A, 20B, 20C, and 20D, an intermediate transfer unit 30, a secondary transfer unit 40, a fixing device 51, a paper transport path 52, a paper feed cassette 53, a manual feed tray 54, and paper discharge. A tray 55 and a control unit 60 are provided. The control unit 60 comprehensively controls each unit of the image forming apparatus 10.

  The image forming apparatus 10 uses an image data corresponding to four hues of black, cyan, magenta, and yellow, which are three subtractive primary colors obtained by color separation of a color image. The image forming process is performed. In the image forming units 20A to 20D, toner images of respective hues are formed. The image forming units 20 </ b> A to 20 </ b> D are arranged in a row in the horizontal direction along the intermediate transfer unit 30.

  Hereinafter, the image forming unit 20A will be mainly described. The image forming units 20B to 20D are configured in substantially the same manner as the image forming unit 20A. The black image forming unit 20A includes a photosensitive drum 21A, a charging device 22A, an exposure device 23A, a developing device 24A, and a cleaning unit 25A, and forms a black toner image through an electrophotographic image forming process.

  The photosensitive drums 21B, 21C, and 21D provided in the photosensitive drum 21A and the image forming units 20B to 20D rotate in one direction when a driving force is transmitted from a driving motor (not shown). The photosensitive drum 21A is a monochrome image carrier, and the photosensitive drums 21B to 21D are color image carriers.

  The charging device 22A is disposed so as to face the peripheral surface of the photosensitive drum 21A, and charges the peripheral surface of the photosensitive drum 21A to a predetermined potential.

  The exposure device 23A irradiates the peripheral surface of the photosensitive drum 21A with a laser beam modulated by the image data for black. As a result, an electrostatic latent image based on the image data for black is formed on the peripheral surface of the photosensitive drum 21A.

  The developing device 24A contains black toner. The developing device 24A develops the electrostatic latent image into a toner image by supplying toner to the peripheral surface of the photosensitive drum 21A.

  The image forming units 20B to 20D form toner images of hues of cyan, magenta, and yellow on the peripheral surfaces of the respective photosensitive drums 21B to 21D.

  The intermediate transfer unit 30 includes an intermediate transfer belt 31, an intermediate transfer drive roller 32, an intermediate transfer driven roller 33, primary transfer rollers 34A to 34D, and an intermediate transfer belt cleaning unit 35.

  The intermediate transfer belt 31 has an endless belt shape, is stretched between an intermediate transfer driving roller 32 and an intermediate transfer driven roller 33, and rotates in a predetermined direction. The intermediate transfer driving roller 32 and the intermediate transfer driven roller 33 are tension rollers that stretch the intermediate transfer belt 31. The outer peripheral surface of the intermediate transfer belt 31 faces the peripheral surfaces of the respective photosensitive drums 21A to 21D of the image forming units 20A to 20D.

  The primary transfer rollers 34A to 34D are arranged so as to face the photosensitive drums 21A to 21D with the intermediate transfer belt 31 interposed therebetween. Regions where the outer peripheral surface of the intermediate transfer belt 31 and the photosensitive drums 21A to 21D are opposed to each other are primary transfer regions.

  A primary transfer bias is applied to the primary transfer rollers 34 </ b> A to 34 </ b> D by constant voltage control with a toner charging polarity (for example, minus) and a reverse polarity (for example, plus). As a result, the toner images of the respective hues formed on the peripheral surfaces of the photosensitive drums 21 </ b> A to 21 </ b> D are primarily transferred in sequence on the outer peripheral surface of the intermediate transfer belt 31, and a full-color toner image is formed on the outer peripheral surface of the intermediate transfer belt 31. It is formed.

  However, when image data of only a part of the hues of yellow, magenta, cyan, and black is input, a part of the four photosensitive drums 21A to 21D corresponding to the hue of the input image data. Only by this, an electrostatic latent image and a toner image are formed. For example, in the monochrome image forming mode, an electrostatic latent image and a toner image are formed only on the photosensitive drum 21A corresponding to the black hue, and only the black toner image is transferred to the outer peripheral surface of the intermediate transfer belt 31.

  The cleaning unit 25A collects toner remaining on the peripheral surface of the photosensitive drum 21A after development and primary transfer.

  The secondary transfer unit 40 is in pressure contact with the intermediate transfer driving roller 32 with the intermediate transfer belt 31 interposed therebetween. A pressure contact portion between the intermediate transfer belt 31 and the secondary transfer unit 40 is a secondary transfer region 92.

  The photosensitive drums 21A to 21D are arranged in order from the side closer to the secondary transfer region 92, the photosensitive drum 21A for black, the photosensitive drum 21B for cyan, the photosensitive drum 21C for magenta, and the photosensitive drum 21D for yellow. Arranged in order. The toner image carried on the outer peripheral surface of the intermediate transfer belt 31 is conveyed to the secondary transfer region 92 as the intermediate transfer belt 31 rotates.

  The paper feed cassette 53 accommodates frequently used size and shape paper. On the manual feed tray 54, paper of a size and shape that is relatively infrequently used is placed. The paper transport path 52 is configured to guide the paper fed from the paper feed cassette 53 or the manual feed tray 54 to the paper discharge tray 55 via the secondary transfer area 92 and the fixing device 51. In this embodiment, at least between the secondary transfer region 92 and the fixing device 51, the paper transport path 52 is arranged in the vertical direction, and the paper is transported upward.

  A registration roller 56 is disposed in the vicinity of the upstream side of the secondary transfer region 92 in the sheet conveyance direction. The registration roller 56 conveys the sheet to the secondary transfer area 92 at a predetermined timing.

  By forming a predetermined secondary transfer electric field in the secondary transfer region 92, the toner image carried on the intermediate transfer belt 31 is secondarily transferred to the sheet.

  Of the toner carried on the intermediate transfer belt 31, the toner remaining on the intermediate transfer belt 31 without being transferred to the paper is collected by the intermediate transfer belt cleaning unit 35. This prevents color mixing in the next step.

  The fixing device 51 includes a heating roller 511 and a pressure roller 512. The heating roller 511 and the pressure roller 512 are in pressure contact with each other. The fixing device 51 heats and presses the sheet by conveying the sheet while sandwiching the sheet at the nip portion between the heating roller 511 and the pressure roller 512, thereby firmly fixing the toner image on the sheet. The sheet on which the toner image is fixed is discharged onto the discharge tray 55 by the discharge roller pair 57.

  As shown in FIG. 2, the secondary transfer unit 40 includes a secondary transfer belt 41, a secondary transfer roller 42, a secondary transfer drive roller 43, a secondary transfer driven roller 44, and a secondary transfer tension roller 45. ing.

  The secondary transfer belt 41 is configured as an endless belt. The secondary transfer belt 41 is stretched by a secondary transfer roller 42, a secondary transfer drive roller 43, a secondary transfer driven roller 44, and a secondary transfer tension roller 45.

  The secondary transfer roller 42 is in pressure contact with the intermediate transfer driving roller 32 with the intermediate transfer belt 31 and the secondary transfer belt 41 interposed therebetween. As a result, the outer peripheral surface of the secondary transfer belt 41 is in pressure contact with the outer peripheral surface of the intermediate transfer belt 31. More specifically, the secondary transfer region 92 is a pressure contact portion between the intermediate transfer belt 31 and the secondary transfer belt 41. The sheet is conveyed to the secondary transfer area 92 to be in close contact with the intermediate transfer belt 31, and the toner image is secondarily transferred by the secondary transfer electric field.

  The image forming apparatus 10 further includes a peeling unit 70. The peeling unit 70 includes a peeling member 71 and a peeling member mounting base 72. The distal end portion of the peeling member 70 has a wedge shape. The peeling member mounting base 72 supports the peeling member 71 so that the front end portion of the peeling member 70 is in pressure contact with the intermediate transfer belt 31 on the downstream side of the secondary transfer region 92 in the rotation direction 91 of the intermediate transfer belt 31. Yes. The peeling member 70 peels the paper wound around the intermediate transfer belt 31 after passing through the secondary transfer region 92 from the intermediate transfer belt 31.

  The peeling member 70 is configured to be movable between a predetermined first peeling position shown in FIG. 2 and a predetermined second peeling position shown in FIG. 3 along a guide member (not shown). In this embodiment, the peeling member 71 is moved manually.

  The first peeling position is a position that is relatively close to the secondary transfer area 92 and is a position that is in pressure contact with the intermediate transfer belt 31 on the downstream side of the secondary transfer area 92 in the rotation direction 91 of the intermediate transfer belt 31. . The second peeling position is relatively far from the first peeling position with respect to the secondary transfer region 92, and the intermediate transfer belt 31 is downstream of the first peeling position in the rotational direction 91 of the intermediate transfer belt 31. This is the position where it presses against.

  The peeling member 71 is preferably disposed so as to be in pressure contact with the intermediate transfer driving roller 32 with the intermediate transfer belt 31 interposed therebetween. As an example, the first peeling position is a position in pressure contact with the peripheral surface of the intermediate transfer driving roller 32 at 30 degrees upward from the horizontal direction around the rotation axis of the intermediate transfer driving roller 32, and the second peeling position is The position is in pressure contact with the peripheral surface of the intermediate transfer drive roller 32 at 90 degrees from the horizontal direction about the rotation axis of the intermediate transfer drive roller 32.

  In FIG. 4, a relatively high performance is indicated by “◯”, and a relatively low performance is indicated by “X”. Further, the paper transportability shown in FIG. 4 indicates the performance of whether or not the paper transport is continued without causing paper jam after the paper hits the peeling member.

  As shown in FIG. 4, when the peeling member 71 is disposed at the first peeling position, the peeling member 71 is in pressure contact with the intermediate transfer belt 31, so that the sheet peelability from the intermediate transfer belt 31 is high.

  Further, since the first peeling position is in the vicinity of the secondary transfer area 92, even if the paper is wound around the intermediate transfer belt 31, the peeling member 71 peels the paper from the intermediate transfer belt 31 immediately after the secondary transfer. For this reason, the leading edge of the sheet does not greatly deviate from the ideal sheet conveyance path when the sheet is not wound around the intermediate transfer belt 31, and the sheet is conveyed toward the fixing device 51 without causing a sheet conveyance defect. Is done. Therefore, the paper transportability is improved.

  However, since the first peeling position is a position in the vicinity of the secondary transfer region 92, the toner remaining on the intermediate transfer belt 31 after the secondary transfer is scraped off by the peeling member 71, and the toner stain on the paper is relatively easy to occur.

  On the other hand, when the peeling member 71 is disposed at the second peeling position, the sheet peelability from the intermediate transfer belt 31 is high as in the case where the peeling member 71 is disposed at the first peeling position. For this reason, it is possible to prevent the sheet from entering deeper than the peeling member 71 when viewed from the secondary transfer region 92 side. Accordingly, even when the peeling member 71 is disposed at the second peeling position, the entry of the paper into the intermediate transfer unit 30 is prevented.

  However, since the second peeling position is farther from the secondary transfer region 92 than the first peeling position, when the paper is wound around the intermediate transfer belt 31, the paper is not ideally wound around the intermediate transfer belt 31. The leading edge of the paper is greatly deviated from the typical paper transport path. For this reason, compared with the case where the peeling member 71 is arrange | positioned in the 1st peeling position, a paper jam is easy to generate | occur | produce and paper conveyance property falls.

  Further, since the second peeling position is farther from the secondary transfer region 92 than the first peeling position, even if the toner remaining on the intermediate transfer belt 31 after the secondary transfer is scraped off by the peeling member 71, the toner Is less likely to adhere to the paper. For this reason, image quality can be improved. In particular, the second peeling position is a position where the second transfer position presses against the peripheral surface of the intermediate transfer drive roller 32 90 degrees upward from the horizontal direction around the rotation axis of the intermediate transfer drive roller 32, that is, the rotation axis of the intermediate transfer drive roller 32 When set on the downstream side in the rotational direction 91 of the intermediate transfer belt 31 from the directly above position including the directly above position, the toner stain on the sheet is further suppressed.

  As described above, it is preferable to dispose the peeling member 71 at the first peeling position when emphasizing paper transportability, and it is preferable to arrange the peeling member 71 at the second peeling position when emphasizing image quality. If the image quality is more important, it may be desirable to avoid even small scratches on the paper that may be caused by the paper hitting the peeling member 71. In some cases, it is more convenient to detect a transport error than transport.

  As shown in FIG. 5, the image forming apparatus 10 includes an operation unit 61 and a display unit 62. The operation unit 61 accepts various input operations such as an image quality mode setting operation. As the image quality mode, a high image quality mode and a normal image quality mode can be set.

  When the image data is input from the image input unit 65, the control unit 60 controls the paper conveyance unit 66 that drives the paper feed roller, the conveyance roller, the registration roller 56, and the load devices of the image forming units 20 </ b> A to 20 </ b> D. Then, an image is formed on the paper.

  The image forming apparatus 10 preferably further includes a position detection unit 63 that detects the position of the peeling member 71 and outputs position information to the control unit 60.

  Next, a first embodiment of the processing procedure of the control unit 60 will be described.

  As shown in FIG. 6, the control unit 60 waits for a print job to be input from the image input unit 65 (S1), and when a print condition is input from the operation unit 61 (S2), the image quality mode is set to high. It is determined whether the image quality mode has been set (S3).

  When the high image quality mode is set, the control unit 60 determines whether or not the peeling member 71 is arranged at the second peeling position based on the position information (S4), and is not arranged at the second peeling position. In this case, the user is notified by displaying, for example, on the display unit 62 that the peeling member 71 should be moved to the second peeling position (S5). In this embodiment, the display unit 62 constitutes a notification unit. In addition, it can also comprise so that a speaker may be provided as a notification part and an audio | voice notification may be performed.

  When the peeling member 71 is disposed at the second peeling position, the control unit 60 repeatedly executes the image forming process until the print job is finished (S6, S7).

  Further, when the normal image quality mode is set, the control unit 60 determines whether or not the peeling member 71 is disposed at the first peeling position based on the position information (S8), and is disposed at the first peeling position. If not, the user is notified by displaying, for example, on the display unit 62 that the peeling member 71 should be moved to the first peeling position (S9). When the peeling member 71 is disposed at the first peeling position, the control unit 60 repeatedly executes the image forming process until the print job is completed.

  According to the image forming apparatus 10 according to the first embodiment, when the high image quality mode is set, since the peeling member 71 is disposed at the second peeling position, it is possible to suppress toner stains on the paper and to improve the image quality. Can be improved. Further, when the normal image quality mode is set, since the peeling member 71 is disposed at the first peeling position, the sheet transportability is improved. Therefore, it is possible to improve performance that places more importance on image quality and paper transportability.

  Next, a second embodiment of the processing procedure of the control unit 60 will be described. In addition, the same code | symbol is attached | subjected to the process similar to the process of 1st Example, and description is abbreviate | omitted.

  The image forming apparatus 10 can further include a peeling member moving mechanism unit 67. The peeling member moving mechanism 67 is configured to move the peeling member 71 between the first peeling position and the second peeling position. As an example, the peeling member moving mechanism unit 67 includes a solenoid or a cam.

  As shown in FIG. 7, when the high image quality mode is set, the control unit 60 controls the peeling member moving mechanism 67 to place the peeling member 71 at the second peeling position (S11).

  Further, when the normal image quality mode is set, the control unit 60 controls the peeling member moving mechanism 67 to place the peeling member 71 at the first peeling position (S12).

  According to the image forming apparatus 10 according to the second embodiment, when the high image quality mode is set, the control unit 60 controls the peeling member moving mechanism portion 67 without moving the peeling member 71 manually. The peeling member 71 is disposed at the second peeling position. For this reason, it is possible to improve the performance that is more important among image quality and paper transportability with better operability.

  Next, a third embodiment of the processing procedure of the control unit 60 will be described. In addition, the same code | symbol is attached | subjected to the process similar to the process of 1st Example, and description is abbreviate | omitted.

  The image forming apparatus 10 can further include a thickness detection unit 64 that detects the thickness of the paper and outputs the thickness information to the control unit 60. For example, a photo sensor is used as the thickness detection unit 64.

  As shown in FIG. 8, the control unit 60 determines whether the paper is thick paper or plain paper based on the thickness information output by the thickness detecting unit 64 detecting the thickness of the paper (S21). Determine (S22). The control unit 60 determines that the paper is thick when the paper thickness is equal to or greater than a predetermined value, and determines that the paper is plain paper when the thickness is less than the predetermined value.

  When the paper is a thick paper, the control unit 60 determines whether or not the peeling member 71 is arranged at the second peeling position based on the position information (S4), and when the paper is not arranged at the second peeling position. The user is notified by displaying, for example, on the display unit 62 that the peeling member 71 should be moved to the second peeling position (S5).

  When the paper is plain paper, the control unit 60 determines whether or not the peeling member 71 is arranged at the first peeling position based on the position information (S8), and when the paper is not arranged at the first peeling position. Notifies the user that the peeling member 71 should be moved to the first peeling position by, for example, displaying it on the display unit 62 (S9).

  When the paper is a thick paper, it can be peeled off from the intermediate transfer belt 31 due to the rigidity of the paper, so that even if the peeling member 71 is disposed at the second peeling position, no paper conveyance failure occurs. For this reason, when the paper is thick paper, the performance of both the image quality and the paper transportability can be improved by disposing the peeling member 71 at the second peeling position. When the paper is plain paper, the paper conveying performance is important and the peeling member 71 is disposed at the first peeling position. As a result, even if the sheet is wound around the intermediate transfer belt 31, the separation member 71 separates the sheet from the intermediate transfer belt 31 immediately after the secondary transfer, so that the sheet is conveyed without causing a sheet conveyance failure. Therefore, it is possible to improve performance that places more importance on image quality and paper transportability.

  In addition, since the thickness of the sheet is detected by the thickness detection unit 64, the user does not need to input whether the sheet is thick paper or plain paper, and the operability is improved. Further, since it is not necessary to perform an input operation and the thickness of the paper is detected by the thickness detection unit 64, there is no possibility of erroneous input, and thickness information can be accurately acquired.

  Next, a fourth embodiment of the processing procedure of the control unit 60 will be described. In addition, the same code | symbol is attached | subjected to the process similar to the process of 1st-3rd Example, and description is abbreviate | omitted.

  As shown in FIG. 9, when the control unit 60 determines that the paper is a thick paper based on the thickness information (S 21) (S 22), the control unit 60 controls the peeling member moving mechanism unit 67 to control the peeling member 71. Is disposed at the second peeling position (S4, S11), and when it is determined that the paper is plain paper, the peeling member moving mechanism 67 is controlled to place the peeling member 71 at the first peeling position (S8). , S12).

  Regardless of the image quality mode, when the paper is thick paper, the controller 60 controls the peeling member moving mechanism 67 to place the peeling member 71 at the second peeling position. When the paper is a thick paper, the paper can be peeled off from the intermediate transfer belt 31 due to the rigidity of the paper, so that both performances of image quality and paper transportability can be improved.

  Further, since the thickness of the sheet is detected by the thickness detection unit 64, it is possible to prevent the possibility of erroneous input of thickness information, and the peeling member moving mechanism unit 67 does not need to move the peeling member 71 manually. Since the member 71 is disposed, the operability is further improved.

  Next, a fifth embodiment of the processing procedure of the control unit 60 will be described. In addition, the same code | symbol is attached | subjected to the process similar to the process of 1st-4th Example, and description is abbreviate | omitted.

  As shown in FIG. 10, the control unit 60 acquires thickness information (S21), and controls the peeling member moving mechanism unit 67 based on the position information when the high image quality mode is set as the image quality mode (S3). By doing so, the peeling member 71 is arranged at the second peeling position (S4, S11).

  When the normal image quality mode is set and the sheet is thick paper (S22), the control unit 60 places the peeling member 71 at the second peeling position. When the normal image quality mode is set and the paper is plain paper, the control unit 60 places the peeling member 71 at the first peeling position (S8, S12).

  Thus, as shown in FIG. 11, when the high image quality mode is set, the peeling member 71 is arranged at the second peeling position regardless of the thickness of the paper. For this reason, it is possible to improve the performance of both image quality and paper transportability.

  When the normal image quality mode is set and the paper is thick paper, the peeling member 71 is disposed at the second peeling position, and when the paper is plain paper, the peeling member 71 is at the first peeling position. Be placed.

  When the paper is a thick paper, it can be peeled off from the intermediate transfer belt 31 due to the rigidity of the paper, so that even if the peeling member 71 is disposed at the second peeling position, no paper conveyance failure occurs. For this reason, even when high image quality is not required, when the paper is thick, the performance of both the image quality and the paper transportability can be improved by disposing the peeling member 71 at the second peeling position. . When high image quality is not required and the paper is plain paper, the peeling member 71 is disposed at the first peeling position with an emphasis on paper transportability. As a result, even if the sheet is wound around the intermediate transfer belt 31, the separation member 71 separates the sheet from the intermediate transfer belt 31 immediately after the secondary transfer, so that the sheet is conveyed without causing a sheet conveyance failure. For this reason, paper conveyance property can be improved. Therefore, it is possible to improve performance that places more importance on image quality and paper transportability.

  Even when the present invention is applied to an image forming apparatus in which the paper conveyance path is arranged in the horizontal direction, the peeling member 71 is moved between the first peeling position and the second peeling position according to the image quality mode or the paper thickness. As a result, it is possible to improve the performance that is more important among the image quality and the paper transportability.

  The above description of the embodiment is to be considered in all respects as illustrative and not restrictive. The scope of the present invention is shown not by the above embodiments but by the claims. Furthermore, the scope of the present invention is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 20A-20D Image forming part 30 Intermediate transfer unit 31 Intermediate transfer belt 32 Intermediate transfer drive roller (stretching roller)
33 Intermediate transfer driven roller (stretching roller)
40 Secondary transfer unit 41 Secondary transfer roller 60 Control unit 61 Operation unit 62 Display unit (notification unit)
63 Position detector 64 Thickness detector 67 Peeling member moving mechanism 71 Peeling member 91 Rotation direction

Claims (7)

An image forming section including an image carrier on which a toner image is formed on the surface;
An intermediate transfer belt that is stretched by a plurality of stretching rollers and is rotatable in a predetermined direction, and onto which a toner image formed on the image carrier is primarily transferred;
A secondary transfer unit that is disposed in pressure contact with the intermediate transfer belt and secondarily transfers the toner image transferred to the intermediate transfer belt to a sheet conveyed through a pressure contact portion between the intermediate transfer belt;
A peeling member for peeling paper from the intermediate transfer belt,
The peeling member includes a predetermined first peeling position that is in pressure contact with the intermediate transfer belt at a downstream side of the press contact portion in the rotation direction of the intermediate transfer belt, and the intermediate transfer at a downstream side of the first peeling position. An image forming apparatus configured to be movable between a predetermined second peeling position in pressure contact with the belt. A peeling member moving mechanism for moving the peeling member between the first peeling position and the second peeling position;
An operation unit for accepting an image quality mode setting operation;
The image forming apparatus according to claim 1, further comprising: a control unit that places the peeling member at the second peeling position when the high image quality mode is set.   When the normal image quality mode is set, the control unit places the peeling member at the second peeling position when the paper is thick paper, and when the paper is plain paper, The image forming apparatus according to claim 2, wherein the image forming apparatus is disposed at a first peeling position. A peeling member moving mechanism for moving the peeling member between the first peeling position and the second peeling position;
The image forming apparatus according to claim 1, further comprising: a control unit configured to dispose the peeling member at the second peeling position when the paper is a thick paper. A thickness detection unit that detects the thickness of the paper and outputs thickness information to the control unit;
The image forming apparatus according to claim 3, wherein the control unit determines an arrangement position of the peeling member based on the thickness information. A position detector that detects the position of the peeling member and outputs position information;
The image forming apparatus according to claim 1, further comprising a notification unit that notifies the position of the peeling member based on the position information. A position detection unit that detects the position of the peeling member and outputs position information;
The image forming apparatus according to claim 2, wherein the control unit controls the peeling member moving mechanism unit based on the position information.

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