JP4848791B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine or a printer that employs an electrophotographic method, and in particular, when an image carrier such as a photosensitive drum is replaced, the image carrier such as the photosensitive drum is accurately positioned. The present invention relates to an image forming apparatus capable of doing so.

JP 2004-258893 A Japanese Patent Application No. 2005-278925

  Conventionally, as an image forming apparatus such as a copying machine or a printer that employs this type of electrophotographic system, for example, a single photosensitive drum is provided, and yellow (Y), magenta is provided on the single photosensitive drum. By sequentially performing image exposure corresponding to each color such as (M), cyan (C), and black (K), yellow (Y), magenta (M), cyan (C), black on the surface of the photosensitive drum. An electrostatic latent image of an image corresponding to each color such as (K) is sequentially formed, and yellow (Y), magenta (M), cyan (C), black (K) are sequentially formed on the surface of the photosensitive drum. ) And the like, the electrostatic latent image of the image corresponding to each color is developed by a developing device of the corresponding color to form a toner image, and yellow (Y) and magenta (M) sequentially formed on the photosensitive drum. ), Cyan (C), and black (K) toner images The so-called “4-cycle method” is configured to form a full-color image by performing multiple primary transfer onto an intermediate transfer belt, then performing secondary transfer from the intermediate transfer belt onto a recording sheet, and fixing. Various image forming apparatuses have been proposed, and are actually commercialized.

  In addition, as the image forming apparatus, image forming units corresponding to respective colors such as yellow (Y), magenta (M), cyan (C), and black (K) are arranged in series and arranged in each image forming unit. By performing image exposure corresponding to each color such as yellow (Y), magenta (M), cyan (C), and black (K) on the photosensitive drum thus formed, the photosensitive drum of each image forming unit An electrostatic latent image of an image corresponding to each color such as yellow (Y), magenta (M), cyan (C), and black (K) is formed on the surface, and the surface of the photosensitive drum of each image forming unit is formed. The electrostatic latent image of the image corresponding to each color such as yellow (Y), magenta (M), cyan (C), black (K) and the like is developed by a developer of the corresponding color to form a toner image. Formed on the photosensitive drum of the image forming unit of each color ), Magenta (M), cyan (C), and black (K) toner images are multiple-primary transferred onto the intermediate transfer belt and then secondarily transferred collectively onto the recording paper from the intermediate transfer belt. Various so-called “tandem-type” image forming apparatuses configured to form full-color images by fixing have been proposed and actually commercialized.

  By the way, in the “4-cycle type” or “tandem-type” image forming apparatus configured as described above, in particular, in the “4-cycle type” image forming apparatus, when the photosensitive drum has reached the end of its service life, etc. In order to improve the performance, the photosensitive drum is integrated with the image forming member such as a charging roll and a cleaning device to form a photosensitive unit, and the user performs an operation of replacing the photosensitive unit from the image forming apparatus main body. It is configured to be

  In that case, in the image forming apparatus, the photosensitive drum of the photosensitive unit is in contact with the intermediate transfer belt by the primary transfer roll. Therefore, when replacing the photosensitive unit, the primary transfer roll and the intermediate transfer belt After the contact state with respect to the photosensitive drum is released, the photosensitive unit is removed from the image forming apparatus main body.

  Therefore, in the image forming apparatus, the user accidentally performs an operation of removing the photosensitive unit from the main body of the image forming apparatus without releasing the contact state of the primary transfer roll and the intermediate transfer belt with the photosensitive drum. It is necessary to prevent the surface of the body drum and the intermediate transfer belt from being damaged.

  Therefore, the present applicant has disclosed Japanese Patent Application Laid-Open No. 2004-258893 and Japanese Patent Application No. 2005-278925 as techniques for preventing the surface of the photosensitive drum and the intermediate transfer belt from being damaged when replacing the photosensitive unit. Has already been proposed.

The image forming apparatus according to Japanese Patent Application Laid-Open No. 2004-258893 transfers an image formed on a photosensitive member to an intermediate transfer member at a primary transfer position, and the image formed on the intermediate transfer member at a secondary transfer position. An image forming apparatus for forming an image on a recording medium by transferring it to the recording medium,
A photoconductor unit that includes the photoconductor and is removable in the direction of the rotation axis of the photoconductor;
A transfer member for transferring an image on the photosensitive member to the intermediate transfer member in contact with the photosensitive member at the primary transfer position;
A plurality of stretching and conveying means for stretching and conveying the intermediate transfer member with a predetermined tension applied thereto;
Tension adjusting means movable in a direction to impart or relieve tension of the intermediate transfer member;
The photosensitive unit can be removed, the transfer member is retracted in the circumferential direction of the intermediate transfer body, the tension of the intermediate transfer body is relaxed by the tension adjusting means, and the photosensitive body and the intermediate transfer body are separated. One-action operation means,
It is comprised so that it may have.

The image forming apparatus according to Japanese Patent Application No. 2005-278925 includes a photoconductor unit including at least a photoconductor on which a toner image is formed, and the photoconductor unit can be pulled out and inserted in the rotation axis direction of the photoconductor. Image forming apparatus,
A regulating member capable of moving the photosensitive unit to a regulating position for regulating movement in the rotation axis direction and a release position for releasing the regulation;
An intermediate transfer belt on which the toner image formed on the photoreceptor is transferred and stretched by a stretching mechanism;
A tension adjusting member provided in the tension mechanism and movable between a tension applying position for applying tension to the intermediate transfer belt and a tension relaxing position for relaxing tension;
A contact member that is movable between a contact position for contacting the intermediate transfer belt with the photosensitive member and a separated position separated from the photoreceptor;
An interlocking mechanism that interlocks the movement of the regulating member, the movement of the contact member, and the movement of the tension adjusting member;
With
The interlocking mechanism is
When the operation lever provided in the interlocking mechanism is moved to one position, the restriction member moves to the restriction position, the contact member moves to the contact position, and the tension adjustment member moves to the tension applying position. With
When the operation lever is moved to the other position, the restriction member is moved to the release position, the contact member is moved to the separation position, and the tension adjusting member is moved to the tension relaxation position.
It is comprised as follows.

  However, the conventional technique has the following problems. That is, in the case of the image forming apparatus according to Japanese Patent Application Laid-Open No. 2004-258893 and Japanese Patent Application No. 2005-278925, particularly in the case of the image forming apparatus according to Japanese Patent Application No. 2005-278925, as shown in FIGS. In addition, the photosensitive member unit 200 is configured to be provided with an operation lever 201 as a restricting member that can be moved between a restricting position for restricting movement in the rotation axis direction and a release position for releasing the restriction. If the operation lever 201 is used only to restrict the movement of the photosensitive unit 200 in the rotation axis direction, the photosensitive drum 202 cannot be fixed against the disturbance F acting on the photosensitive drum 202. The positions of the photoconductive drum 202 are yellow (Y), magenta (M), cyan (C), black (K) on the near side and the far side along the axial direction. Of fluctuates for each color, the color registration is deteriorated an image forming position of each color, image quality has been a problem of a decrease.

  More specifically, in the case of the image forming apparatus according to Japanese Patent Application No. 2005-278925, as shown in FIG. 19, the photosensitive drum 202 of the photosensitive unit 200 is positioned on the near side along the rotation axis direction. The support member 204 is rotatably supported by the support member 204, and the position of the support member 204 along the axial direction of the photosensitive drum 202 is restricted by an operation lever 201 as a restriction member.

  On the surface of the photosensitive drum 202 of the photosensitive unit 200, as shown in FIG. 20, developing units 205 for yellow (Y), magenta (M), cyan (C), and black (K) are provided. The developing roller 206 of the developing device 205 of the color to be developed is rotatably arranged at both end portions along the axial direction of the developing roller 206 by rotating the rotary developing device mounted along the circumferential direction. It is configured to abut via the tracking roll 207.

  Further, in the rotary type developing device in which the developing devices 205 of the respective colors of yellow (Y), magenta (M), cyan (C), and black (K) are mounted along the circumferential direction, the weight of the developing device 205 of each color. Depending on the amount of toner consumed, the toner cartridge of the developing device 205 of black (K) color, which is particularly large in use amount, may be configured larger than the developing device 205 of other colors. The developing devices 205 for each color of Y), magenta (M), cyan (C), and black (K) have different weights.

  Therefore, in the rotating type developing device, among the developing devices of each color of yellow (Y), magenta (M), cyan (C), and black (K), the developing device 205 of the color to be developed is included in the photosensitive unit 200. When moved to the developing position facing the surface of the photosensitive drum 202, the photosensitive drum 202 of the photosensitive unit 200 is moved to the developing position via the tracking roll 207 according to the weight of the developing unit moved to the developing position. The reaction force F acts as a disturbance.

  As a result, as shown in FIG. 20, the photosensitive drum 202 of the photosensitive unit 200 is larger than the developing unit 205 having a toner cartridge with a large amount of remaining toner and other color developing units. When the black developing device 205 having the configured toner cartridge moves to the developing position, a large reaction force F is received as a disturbance from the developing device 205 moved to the developing position. Therefore, in the position restriction along the axial direction of the photosensitive drum 202 by the operation lever 201, the position along the axial direction of the photosensitive drum 202 cannot be sufficiently restricted, and the position along the axial direction of the photosensitive drum 202 is not satisfied. The tracking pressure by the tracking roll 207 fluctuates between the front side and the back side, and the rotation shaft of the photosensitive drum 202 is inclined between the front side and the back side, or the photosensitive drum 202 moves along the axial direction. When the yellow (Y), magenta (M), cyan (C), and black (K) toner images formed on the photosensitive drum 202 are transferred onto the intermediate transfer belt 208, skew is generated. Or a misregistration along the axial direction of the photosensitive drum, resulting in a problem that color image registration deteriorates and image quality deteriorates.

  Accordingly, the present invention has been made to solve the above-described problems of the prior art, and the object of the present invention is that the work of exchanging an image carrier such as a photosensitive drum can be easily performed. Of course, an object of the present invention is to provide an image forming apparatus capable of preventing deterioration of image registration due to image registration deterioration even when an image carrier such as a photosensitive drum is replaced. .

That is, the invention described in claim 1 includes an image carrier unit including at least an image carrier on which a toner image is formed, and an intermediate transfer belt on which the toner image formed on the image carrier is transferred. The image carrier unit is configured to be detachable from the image forming apparatus main body along the axial direction of the image carrier.
A tensioning mechanism that can be switched between a tension applying position where tension is applied to the intermediate transfer belt, and a tension relaxation position where tension is relaxed;
A contact member that moves the intermediate transfer belt to a contact position that contacts the image carrier and a spaced position that is separated from the image carrier in conjunction with the switching operation of the stretching mechanism;
An operation member for performing an operation of switching the tension mechanism between a tension applying position and a tension relaxation position;
An image forming system comprising: a preload applying member that applies a preload that stops movement along the axial direction to the image carrier unit in conjunction with an operation of switching the operation member to a tension applying position. Device.

  According to a second aspect of the present invention, the stretching mechanism moves a tension adjusting roll among a plurality of rolls stretching the intermediate transfer belt to a tension applying position and a tension relaxing position. The image forming apparatus according to claim 1, comprising a mechanism.

  Furthermore, the invention described in claim 3 is provided with a second preload applying member that applies preload to the image carrier unit in a direction orthogonal to the axial direction. This is an image forming apparatus.

  According to the present invention, the image bearing member such as the photosensitive drum can be easily replaced, and even when the image bearing member such as the photosensitive drum is replaced, the resist for the image can be obtained. It is possible to provide an image forming apparatus capable of preventing the image quality from being deteriorated due to deterioration of the image quality.

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

Embodiment 1
FIG. 2 is a block diagram showing a "4-cycle" type color multifunction peripheral as an image forming apparatus according to Embodiment 1 of the present invention. This color multifunction machine also has a function as a copying machine, a printer, or a facsimile.

  As shown in FIG. 2, the color multifunction peripheral includes a scanner 2 as an image reading device on the upper portion of the multifunction peripheral body 1 and is connected to a personal computer (not shown) via a network (not shown). . Further, the color multi-function peripheral is equipped with a post-processing device 3 on the right side of the multi-function main body 1 for performing post-processing such as perforation processing and binding processing on paper on which an image is formed by the color multi-function peripheral. Has been.

  The color multifunction device functions as a fax machine that copies an image of a document read by the scanner 2, prints it based on image data sent from a personal computer, and transmits / receives image data via a telephone line. It is supposed to be.

  In FIG. 2, reference numeral 1 denotes a main body of a color multifunction peripheral. An automatic document feeder (ADF) that automatically conveys unshown originals one by one is provided on the upper portion of the color multifunction peripheral main body 1. 4) and a scanner 2 for reading an image of a document conveyed by the automatic document conveying device 4. The automatic document feeder 4 also functions as a platen cover. The scanner 2 illuminates a document placed on a platen glass (not shown) with a light source 5, and reduces the reflected light image from the document by a full-rate mirror 6, half-rate mirrors 7 and 8, and an imaging lens 9. Scanning exposure is performed on an image reading element 10 composed of a CCD or the like via a system 11, and the color material reflected light image of the original is read by the image reading element 10 at a predetermined dot density (for example, 16 dots / mm). It has become.

  The reflected light image of the document read by the scanner 2 is transmitted to the image processing apparatus 12 (IPS) as reflectance data of three colors of red (R), green (G), and blue (B) (8 bits each), for example. The image processing apparatus 12 performs processing such as shading correction, position shift correction, brightness / color space conversion, gamma correction, frame deletion, color / moving editing, and the like on the image data of the document as necessary. In addition, predetermined image processing is performed as will be described later. The image processing apparatus 12 also performs predetermined image processing on image data sent from a personal computer (not shown) or the like.

  The image data that has been subjected to the predetermined image processing by the image processing device 12 is similarly processed by the image processing device 12 to yellow (Y), magenta (M), cyan (C), black (K) (each 8 bits). ) Image data of four colors and sent to a ROS (LaserOutputScanner) 13 as an image exposure apparatus. In the ROS 13 as the image exposure apparatus, yellow (Y), magenta (M), cyan (C), black (K) Image exposure with the laser beam LB is sequentially performed at a predetermined timing in accordance with image data of four colors (8 bits each). Of course, in a color complex machine, not only a color image but also a monochrome image may be formed.

  By the way, a photosensitive drum 14 serving as an image carrier is disposed in the color MFP main body 1 at a position slightly to the left of the center so as to be rotatable along the direction of the arrow. As this photosensitive drum 14, for example, a photosensitive cylinder having a surface coated with a photosensitive layer such as OPC is used, and is rotated at a predetermined process speed in the direction of the arrow by a driving means (not shown). Driven.

  This color multi-function peripheral has a process speed of about 160 mm / sec, which is set to be relatively high in similar models, and has high productivity. It should be noted that the process speed of the color multifunction device may be set to be faster than 160 mm / sec in the monochrome mode, for example.

  The surface of the photosensitive drum 14 is charged to a predetermined potential by a charging roll 15 serving as a charging unit disposed immediately below the photosensitive drum 14, and is then positioned obliquely below the photosensitive drum 14. Image exposure by a laser beam (LB) is performed by a ROS 13 (Raster Output Scanner) as an arranged image exposure apparatus, and an electrostatic latent image corresponding to image information is formed. In the ROS 13, for example, image exposure based on image data corresponding to each color of yellow (Y), magenta (M), cyan (C), and black (K) is sequentially performed at a predetermined timing. The electrostatic latent image sequentially formed on the photosensitive drum 13 passes through the developing devices 16Y, 16M, 16C, and 16K for each color of yellow (Y), magenta (M), cyan (C), and black (K). The toner is developed by the rotary developing device 16 arranged along the direction, and becomes a toner image of a corresponding color.

  As shown in FIGS. 2 and 3, the rotary developing device 16 includes four developing devices 16Y, 16M, 16C, yellow (Y), magenta (M), cyan (C), and black (K). 16K is mounted so as to form a predetermined angle along the circumferential direction of the rotating frame that rotates about the rotation axis. The four developing devices 16Y, 16M, 16C, and 16K of yellow (Y), magenta (M), cyan (C), and black (K) are provided with the rotation position of the rotation frame on the rotation frame. By detecting and controlling according to the position of the slit (not shown), the developing roll 17 provided in the opening of each developing device 16Y, 16M, 16C, 16K is placed at the developing position facing the photosensitive drum 14. The electrostatic latent image formed on the photosensitive drum 14 is stopped and developed with the corresponding color toner.

  Further, the yellow (Y), magenta (M), cyan (C), and black (K) developing devices 16Y, 16M, 16C, and 16K are adjacent to the developing devices 16Y, 16M, 16C, and 16K. As described above, the toner cartridges 18Y, 18M, 18C, and 18K are mounted, and the toner of the corresponding color from the toner cartridges 18Y, 18M, 18C, and 18K is supplied to the developing units 16Y, 16M, 16C, and 16K at a predetermined timing. By supplying the toner, it is possible to adjust the toner density in each of the developing devices 16Y, 16M, 16C, and 16K.

  In this embodiment, as shown in FIGS. 2 and 3, of the four toner cartridges 18Y, 18M, 18C, and 18K of yellow (Y), magenta (M), cyan (C), and black (K), The black (K) toner cartridge 18K that consumes the largest amount of toner is formed larger than the toner cartridges 18Y, 18M, and 18C of other colors, and the black (K) toner cartridge 18K includes It is configured so that a large amount of toner can be accommodated. Therefore, the black (K) toner cartridge 18K is the heaviest.

  On the surface of the photosensitive drum 14, the charging, exposure, and development processes are repeated a predetermined number of times according to the color of the image to be formed. In the rotary developing device 16, the developing rollers 17 of the corresponding color developing devices 16 </ b> Y, 16 </ b> M, 16 </ b> C, and 16 </ b> K move to the developing position facing the photosensitive drum 14. For example, when a full-color image is formed, the charging, exposure, and development processes are performed on the surface of the photosensitive drum 14 in yellow (Y), magenta (M), cyan (C), and black (K) colors. The toner image corresponding to each color of yellow (Y), magenta (M), cyan (C), and black (K) is sequentially formed on the surface of the photosensitive drum 14. .

  When a black and white image is formed, the charging, exposure, and development processes are performed only once on the surface of the photosensitive drum 14 corresponding to the black (K) color. Only the toner image corresponding to the black (K) color is formed on the surface.

  The yellow (Y), magenta (M), cyan (C), and black (K) toner images sequentially formed on the photosensitive drum 14 are formed on the outer periphery of the photosensitive drum 14 as intermediate transfer members. At the primary transfer position where the intermediate transfer belt 19 comes into contact, primary transfer is performed by the primary transfer roll 20 while being superimposed on the intermediate transfer belt 19. When a black and white image is formed, a black (K) toner image is primarily transferred to the surface of the photosensitive drum 14 only once by the primary transfer roll 20.

  The yellow (Y), magenta (M), cyan (C), and black (K) toner images transferred in multiple onto the intermediate transfer belt 19 are fed by the secondary transfer roll 21 at a predetermined timing. Secondary transfer is collectively performed on a recording sheet 22 as a recording medium at a secondary transfer position.

  As shown in FIG. 2, the recording paper 22 is fed with a predetermined size and a desired material from any one of a plurality of paper feed trays 23, 24, and 25 arranged at the lower part of the color MFP main body 1. In a state where the sheets are separated one by one by the roll 26, the separation roll 27, and the retard roll 28, the paper is fed through a paper conveyance path 30 provided with a conveyance roll 29. Then, the recording paper 22 fed from one of the paper feed trays 23, 24, and 25 is temporarily stopped by the registration roll 31, and is intermediated by the registration roll 31 in synchronization with the image on the intermediate transfer belt 19. The transfer belt 19 is conveyed to the secondary transfer position. Note that when the toner image is secondarily transferred from the intermediate transfer belt 19 onto the recording paper 22, toner as a developer, an external additive of the toner, or the like remains on the intermediate transfer belt 19 due to adhesion. There is a case.

  As shown in FIGS. 2 and 3, the intermediate transfer belt 19 is stretched by a plurality of rolls and is brought into contact with the surface of the photosensitive drum 14 at the primary transfer position, so that a predetermined process speed ( It is configured to be driven to rotate at about 160 mm / sec). The intermediate transfer belt 19 is formed in an endless belt shape by synthetic resin such as polyimide resin, for example. The intermediate transfer belt 19 includes a drive roll 32, a primary transfer roll 20 that transfers a toner image formed on the photosensitive drum 14 onto the intermediate transfer belt 19, a sensor roll 33, a tension adjustment roll 34, The secondary transfer roll 21 is stretched with a predetermined tension by a backup roll 35 that is in contact with the intermediate transfer belt 19 via the intermediate transfer belt 19.

  Further, as described above, the intermediate transfer belt 19 is stretched by a plurality of rolls 20, 32 to 35. In this embodiment, in order to reduce the size of the color MFP main body 1, the intermediate transfer belt 19 is used. The cross-sectional shape over which 19 is stretched is configured to be a flat, elongated, approximately isosceles triangle.

  Further, at a position facing the sensor roll 33 of the intermediate transfer belt 19, a density detection means comprising a reflection type photosensor for detecting the density of a toner test patch as a density detection pattern formed on the intermediate transfer belt 6. An automatic density detection (ADC) sensor 36 is provided.

  Then, the recording paper 22 on which the toner images of the respective colors are transferred is fixed with heat and pressure by a heating roll 38 and a pressure belt (or pressure roll) 39 of a fixing device 37 as shown in FIGS. After receiving the processing, the first sheet is conveyed by the conveyance roll 40 via the first sheet conveyance path 42 for discharging the image forming surface downward to the face-down tray 41 as the first discharge tray. The paper is discharged onto a face-down tray 41 provided at the top of the multi-function device body 1 by a discharge roll 43 provided at the exit of the conveyance path 42.

  Further, when the recording paper 22 on which an image is formed as described above is discharged with the image forming surface facing upward, as shown in FIG. 2, the face as a second discharge tray with the image forming surface facing upward. A discharge roller 46 provided at the outlet of the second paper transport path 45 through the second paper transport path 45 for discharging to the up tray 44 causes a side portion (left side in the drawing) The sheet is discharged onto a face-up tray 44 provided on the surface).

  As described above, the post-processing device 3 is mounted on the right side surface of the color MFP main body 1, and punching processing, binding processing, and the like are performed on the recording paper 22 on which an image is formed by the color MFP. When post-processing is performed, the recording paper 22 on which the toner image has been fixed by the fixing device 37 is discharged by the discharge roll 47, and the paper is transported inside the transport unit 48 constituting the face-down tray 41. It is configured to be conveyed to the post-processing device 3 through the path 49 and to perform post-processing by the post-processing device 3.

  Further, in the above-mentioned color multi-function machine, when making full-color double-sided copying, as shown in FIG. 2, the recording paper 22 having an image fixed on one side is directly placed on the face-down tray 41 by a discharge roll 43 or the like. Without discharging, the transfer direction is switched by the switching gate and guided to the discharge roll 47. While the rear end of the recording paper 22 is sandwiched by the discharge roll 47, the discharge roll 47 is temporarily stopped and then reversely rotated. Then, the paper is transported to the double-sided paper transport path 50 by the discharge roll 47. In this double-sided paper conveyance path 50, the recording roller 22 provided along the conveyance path 50 is conveyed again to the registration roll 31 with the recording paper 22 turned upside down. After the image is transferred and fixed on the back surface of the recording paper 22, it is discharged to either the face-down tray 41 or the face-up tray 44 via the first paper transport path 42 or the second paper transport path 45. Is done.

  In FIG. 2, 52 is a manual feed tray for feeding a desired recording paper 22, 53 is a cleaning device for cleaning the surface of the photosensitive drum 14, 54 is a cleaning device for cleaning the surface of the intermediate transfer belt 19, and 55. Indicates a collection box for collecting the toner removed by the cleaning device 54.

  The cleaning device 54 is separated from the surface of the intermediate transfer belt 19 until the final color toner image passes, and contacts the surface of the intermediate transfer belt 19 after the final color toner image passes. It is configured as follows.

By the way, this embodiment includes an image carrier unit including at least an image carrier on which a toner image is formed, and an intermediate transfer belt to which the toner image formed on the image carrier is transferred. In the image forming apparatus configured to be detachable from the image forming apparatus main body along the axial direction of the image carrier,
A tensioning mechanism that can be switched between a tension applying position where tension is applied to the intermediate transfer belt, and a tension relaxation position where tension is relaxed;
A contact member that moves the intermediate transfer belt to a contact position that contacts the image carrier and a spaced position that is separated from the image carrier in conjunction with the switching operation of the stretching mechanism;
An operation member for performing an operation of switching the tension function between a tension application position and a tension relaxation position;
In conjunction with the operation of switching the operation member to the tension applying position, a preload applying member is provided that applies a preload that stops movement along the axial direction to the image carrier unit.

  That is, in this embodiment, as shown in FIG. 3, the photosensitive drum 14 as an image carrier constitutes a photosensitive unit 60 that is unitized together with the charging roll 15 and the cleaning device 53. The photoconductor unit 60 is detachable from the color MFP main body 1. As shown in FIG. 4, the photosensitive unit 60 has the photosensitive drum 14, the charging roll 15, and the like with the front cover 61 of the color MFP main body 1 opened, such as when the photosensitive drum 14 reaches the end of its life. Can be replaced with a new one by detaching from the main body 1 of the color multifunction device or attaching it.

  As shown in FIG. 5, the photosensitive unit 60 includes a housing 62 positioned on the side surface of the photosensitive drum 14 on the cleaning device 53 side, and extends along the axial direction of the photosensitive drum 14 of the housing 62. At both ends, side panels 63 and 64 on the front side (front side) and the back side (rear side) for rotatably holding the photosensitive drum 14 are integrally provided. Further, a cleaning device 53 and a charging roll 15 are disposed inside the housing 62 so as to contact the surface of the photosensitive drum 14. Further, as shown in FIG. 1, a shaft member 65 that rotatably supports the photosensitive drum 14 is fixed to the front side panel 63, and a rear side panel 64 is attached. As shown in FIG. 5, the rear side of the photosensitive drum 14 is temporarily held. The photoconductor drum 14 is separated from the rear side panel 64 in a state where the photoconductor unit 60 is mounted on the color multifunction machine main body 1.

  Further, as shown in FIG. 6, the photosensitive unit 60 is mounted on the front side panel 63 when the photosensitive unit 60 is mounted at a predetermined position on the main unit 1 of the color complex machine. The positioning holes 68 and 69 for fitting with the positioning pins 66 and 67 are formed at positions different from each other by approximately 180 degrees, and the side panel 64 on the rear side thereof positions the positioning of the color multifunction peripheral body 1. A positioning hole 71 for fitting with the pin 70 is formed at a position corresponding to the positioning hole 69 of the front side panel 63.

  As shown in FIG. 1, the positioning pins 66 and 67 are the frame 101 on the front side of the color multifunction machine main body 1 and in a position close to the opening where the photoconductor unit 60 is attached and detached. It is planted so as to protrude toward the front side.

  As shown in FIGS. 1 and 6, the photosensitive unit 60 has three positioning pins protruding from a predetermined position of the color MFP main body 1 when mounted on the color MFP main body 1. 66, 67, and 70 are fitted into positioning holes 68, 69, and 71 formed in the front and rear side panels, and are also projected at predetermined positions on the color MFP main body 1. By engaging the rotating shaft 72 of the photoconductive drum 14 with the engaging hole 73 exposed on the rear side of the photoconductive drum 14 of the photoconductive unit 60, the photoconductive drum 14 is brought into a predetermined position of the color multifunction machine main body 1. It is configured to be rotatably mounted.

  As shown in FIG. 1, the rotating shaft 72 is implanted in the frame 102 on the rear side of the color multifunction peripheral body 1.

  When forming a color or monochrome image with the photosensitive drum 14 rotatably mounted at a predetermined position of the color MFP main body 1 as described above, yellow (Y) and magenta (M) of the rotary developing device 16 are formed. , Cyan (C), and black (K) of the four developing devices 16Y, 16M, 16C, and 16K, the developing device of a predetermined color is located at the developing position facing the photosensitive drum 14, as shown in FIG. The electrostatic latent image formed on the photosensitive drum 14 is developed by moving and stopping.

  At this time, the four developing devices 16Y, 16M, 16C, and 16K of yellow (Y), magenta (M), cyan (C), and black (K) of the rotary developing device 16 have their developing rolls 17 exposed to light. When moved to the developing position facing the body drum 14, the tracking rollers 73 and 74 rotatably provided at both ends in the axial direction of the developing roller 17 of the developing units 16Y, 16M, 16C, and 16K are photosensitive members. The distance (DRS) between the developing roll 17 and the surface of the photosensitive drum 14 is maintained at a predetermined value by contacting the surfaces of the flange portions 14a and 14b located at both ends in the axial direction of the drum 14. Has been.

  Further, in the color composite machine configured as described above, as shown in FIGS. 2 and 3, the intermediate transfer belt 19 is in contact with the surface of the photosensitive drum 14 by the primary transfer roll 20, so that it remains as it is. Then, the photosensitive drum 14 cannot be replaced.

  Therefore, in the color multifunction peripheral, as shown in FIG. 1, when the photosensitive drum 14 is replaced by the photosensitive unit 60, the primary transfer roll 20 is moved to the transfer position by operating the operating lever 75 as an operating member. At the same time, the tension of the intermediate transfer belt 19 is relaxed and separated from the surface of the photosensitive drum 14.

  Next, a tension mechanism for stretching the intermediate transfer belt 19 will be described.

  As shown in FIG. 7, the intermediate transfer belt 19 is stretched by a drive roll 32, a primary transfer roll 20, a sensor roll 33, a tension adjusting roll 34, and a backup roll 35. By being rotationally driven, it is configured to circulate along the direction of the arrow M.

  As shown in FIG. 7, the tension adjusting roll 34 is rotatably attached to the tip of the first arm 76, and the first arm 76 is attached in a state where the position is fixed to the color multifunction peripheral body 1. The swing shaft 77 is swingable about the center. The first arm 76 is connected to the cam 80 via a connecting arm 79 having a tension spring 78. As shown in FIG. 8, the connecting arm 79 is configured by winding a tension spring 78 around the outer periphery of the connecting shaft 81. In the connecting portion between the connecting arm 79 and the cam 80, the connecting shaft 81 is inserted into the first arm 76 and the cam 80 so as not to come off. Therefore, as shown in FIG. 7, the restoring force of the tension spring 78 generates a force for rotating the first arm 76 in the direction of the arrow R <b> 1, and the tension adjusting roll 34 is applied to the intermediate transfer belt 19 by this force. A predetermined tension is applied.

  As shown in FIG. 8, the primary transfer roll 20 is rotatably attached to a second arm 82 that swings around the rotation shaft 77 described above. The primary transfer roll 20 is configured to abut on the inner peripheral surface of the intermediate transfer belt 19 and press the intermediate transfer belt 19 against the surface of the photosensitive drum 14.

  4, the user opens the front cover 61 of the color MFP main body 1 and rotates the operation lever 75 approximately 90 degrees along the clockwise direction as shown in FIG. From the state, the state becomes the state shown in FIG.

  Next, the drawer and insertion (detachment) of the photoreceptor unit 60 will be described in detail.

  In a state where the photoconductor unit 60 is inserted and mounted inside the color MFP main body 1, the operation lever 75 is on the front side of the side panel 63 on the front side of the photoconductor unit 60 as shown in FIG. And in contact with the front side panel 63, the movement of the photosensitive unit 60 in the direction of the rotation axis X is restricted. Further, the operation lever 75 overlaps and covers a part of the side panel 63 on the front side of the photoreceptor unit 60 when viewed in the rotation axis X direction. The position of the operation lever 75 shown in FIG.

  By the way, in this embodiment, it is provided with a preload applying member that applies a preload for stopping movement along the axial direction to the image carrier unit in conjunction with the operation of switching the operation member to the tension applying state. It is configured.

  That is, the front side panel 63 of the photoconductor unit 60 is attached to a position corresponding to the restriction position of the operation lever 75 in a direction protruding by the coil spring 110 as an urging member, as shown in FIG. A stopper 111 as a biased preload applying member is disposed so as to be able to appear and retract. As shown in FIG. 1, the stopper 111 is composed of an annular flange member 112 and a protruding portion 113 protruding in a convex shape on the front side. The inner surface of the protruding portion 113 and the side on the front side are formed. A compressed coil spring 110 is interposed between the inner surface 63 a on the back side of the panel 63. The protrusion 113 of the stopper 111 is normally brought into contact with the inner surface 63b of the front side panel 63 by the annular flange member 112 by the biasing force of the coil spring 110 as shown in FIG. It protrudes in the state.

  The protrusion amount of the protrusion 113 of the stopper 111 is determined by the amount of preload applied to the photoconductor unit 60, etc. The amount of preload is only the protrusion amount (displacement amount) of the protrusion 113. In addition, since it depends on the spring constant of the coil spring 110, if the spring constant of the coil spring 110 is set large, the protrusion amount of the protrusion 113 may be small.

  The stopper 111 is in a state of being pushed and pushed by the operation lever 75 as shown in FIG. 1 in a state where the operation lever 75 is rotated to the restriction position, and due to the repulsive force of the coil spring 110, A preload is applied to the photoconductor unit 60 to stop the movement toward the front side in the axial direction.

  Further, the stopper 111 is provided with an inclined surface on the back surface of the operation lever 75 so that the operation lever 75 is smoothly pushed by the operation lever 75 to the restriction position. It is desirable to form the protruding portion 113 of the stopper 111 into a curved shape.

  Further, as shown in FIG. 5, when the roller 83 is provided on the downstream side of the rotation direction of the operation lever 75 of the stopper 111 in the photosensitive unit 60, the load when the stopper is pushed, the operation lever In order to avoid an excessive operation force (rotational power) of the operation lever 75 due to an overlap with the load when the 75 comes into contact with the roller 83, the stopper 111 and the roller are moved along the rotation direction of the operation lever 75. Alternatively, the position of 83 may be shifted, or as shown in FIG. 11, only the roller 83 may be provided instead of the stopper 111, and the roller 83 may be urged by the coil spring 110.

  Further, as shown in FIG. 1 and FIG. 12, stop members 114 and 115 for stopping the position of the photoconductor unit 60 when preload is applied to the photoconductor unit 60 by the stopper 111. It is mounted in a state of being inserted into positioning pins 66 and 67 that pass through positioning holes 68 and 69 provided in the side panel 63 on the front side. The restriction members 114 and 115 are formed in a cylindrical shape by a synthetic resin, metal, or elastic member. FIG. 12 shows a state in which the photosensitive unit 60 is removed from the color multifunction peripheral main body 1.

  As described above, when the operation lever 75 is in the restricting position as shown in FIG. 1, the photoconductor unit 60 cannot be pulled out to the front side.

  As shown in FIG. 9, when the user rotates the operation lever 75 approximately 90 degrees along the clockwise direction and moves it to a retracted position that does not overlap the photoreceptor unit 60, the rotation axis of the photoreceptor unit 60 is rotated. The restriction on the movement in the X direction is released, and the photosensitive unit 60 can be pulled out to the front side. The position of the operation lever 75 shown in FIG.

  As described above, when the operation lever 75 is located at the release position, the photoreceptor unit 60 can be attached to the color multifunction device main body 1 by inserting the photoreceptor unit 60 into the back side. Yes.

  Now, as shown in FIG. 9, the side panel 63 on the front side of the photoconductor unit 60 is provided with a roller 83 on the front side of the restriction position.

  On the other hand, as shown in FIG. 13, a substantially grid-like rib 84 is formed on the back surface 75 a of the operation lever 75, and the rib 84 of the back surface 75 a has a recess at a position corresponding to the roller 83. 85 is formed. When the operation lever 75 moves to the restriction position, the roller 83 of the side panel 63 on the front side of the photoreceptor unit 60 is engaged with the recess 85 on the back surface 75a of the operation lever 75. .

  As described above, when the operation lever 75 is rotated from the release position to the restriction position, the operation lever 75 can be smoothly rotated by rotating the roller 83 in contact with the back side surface 75a of the operation lever 75. It can be done. Further, the roller 83 of the photoconductor unit 60 is engaged with the recess 85 of the operation lever 75 so that a click feeling is generated. Further, the concave portion 85 of the operation lever 75 and the roller 83 of the photosensitive unit 60 serve as a guide for positioning reference in the rotation axis direction X, respectively.

  By the way, when the photoreceptor unit 60 is pulled out and inserted, if the photoreceptor drum 14 and the intermediate transfer belt 19 are rubbed with each other, the photoreceptor drum 14 and the intermediate transfer belt 19 are damaged. Accordingly, in conjunction with the operation lever 75 being rotated to move from the restriction position to the release position, the second arm 82 is rotated as shown in FIG. 9, and the primary transfer roll 20 is moved to the photosensitive drum 14. The first arm 76 swings and the tension adjusting roll 34 moves toward the inner peripheral side (in the direction of arrow R2) of the intermediate transfer belt 19 and retracts in the direction of the arrow R3 that is separated from the tension. It has an interlocking mechanism that relaxes the problem.

  This interlocking mechanism is configured as follows.

  8 shows a state when the operation lever 75 shown in FIG. 7 is in the restricting position, FIG. 14 shows a state when the operation lever 75 shown in FIG. 9 is in the release position, and FIG. Shows a state in which is at an intermediate position between the restriction position and the release position (intermediate between FIGS. 8 and 14). In FIG. 14, the intermediate transfer belt 19 is pushed up from the outside by a roll (not shown) of the second arm 82, and the intermediate transfer belt 19 is separated from the photosensitive drum 14 together with the primary transfer roll 20. Yes.

  Further, a position where the tension adjusting roll 34 applies tension to the intermediate transfer belt 19 is set as a tension applying position, and a position where tension is relaxed is set as a tension relaxing position. Further, the position at which the primary transfer roll 20 contacts the intermediate transfer belt 19 with the photosensitive drum 14 is defined as a contact position, and the separated position is defined as a separation position.

  As shown in FIGS. 7 and 8, the operation lever 75 is attached to the front end portion of the rotation shaft 86, and a cam 87 is provided near the front end portion of the rotation shaft 86. It is attached. The cam 87 is provided with a convex portion 88, and the convex portion 88 is engaged with a concave portion 89 formed at the tip portion of the second arm 82 to which the primary transfer roll 20 is attached. ing. The cam 87 is also provided with a contact portion 90 at an angle different from that of the convex portion 88, and the side surface 90A of the contact portion 90 is attached with a tension adjusting roll 34 as shown in FIG. The side surface 80A of the cam 80 connected to the first arm 76 via the connecting arm 79 is brought into contact.

  The cam 80 is rotatable about a rotation shaft 91. The rotation shaft 91 of the cam 80 is disposed in the vicinity of a line connecting the rotation shaft 86 of the operation lever 75 and the common rotation shaft 77 of the arm 76 and the arm 82.

  When the operation lever 75 is in the restricting position, as shown in FIG. 8, the convex portion 88 of the cam 87 engages with the concave portion 89 of the arm 81, and the primary transfer roll 20 attached to the arm 82 is brought into the contact position. The intermediate transfer belt 19 is pressed against the photosensitive drum 14.

  Further, when the operation lever 75 is in the restricting position, the side surface 80A of the cam 80 abuts against the side surface 90A of the abutting portion 90, so that the rotation of the cam 80 is restricted, and the tension adjusting roll 34 is moved to the tension applying position. Become. Further, tension is applied to the intermediate transfer belt 19 by the urging force of the tension spring 78.

  Further, the second arm 82 to which the primary transfer roll 20 is attached is formed with a cylindrical stud 92 that abuts against the slope 80B on the side surface of the cam 80, as shown in an enlarged view in FIG. ing.

  When the operation lever 75 is turned as shown by the arrow W1, the cam 87 is rotated as shown by the arrow W2, as shown in FIG. When the cam 87 rotates, the contact portion 90 moves. That is, the contact surface 90A with which the side surface 80A of the cam 80 abuts slides. For this reason, the cam 80 rotates about the rotation shaft 91 as shown by the arrow W3 by the urging force of the tension spring 78.

  As the cam 80 rotates, the first arm 76 connected via the connecting arm 79 rotates, and the tension adjusting roll 34 also moves in the direction of the arrow R2.

  On the other hand, the rotation of the cam 87 releases the engagement between the convex portion 90 of the cam 87 and the concave portion 89 of the second arm 82, and the side surface of the convex portion 90 comes into contact with the upper end portion of the concave portion 89. The second arm 82 is rotated in the direction of arrow W5. Further, the stud 92 of the second arm 82 moves along the slope 80 </ b> B on the side surface of the cam 80. Therefore, the primary transfer roll 20 moves in the arrow R3 direction.

  As shown in FIGS. 9 and 14, when the operation lever 75 is in the release position, the stud 92 gets over the corner 80D at the end of the slope 80B as shown in an enlarged view in FIG. Move to the upper surface 80C. For this reason, a click feeling is generated and the entire interlocking mechanism is locked.

  That is, the operation lever 75 is fixed at the release position, the tension adjusting roll 34 is fixed at the tension relaxation position, and the primary transfer roll 20 is fixed at the separated position. In other words, even when the user releases the operation lever 75, the states of FIGS. 9 and 12 are maintained.

  Thus, as shown in the order of FIGS. 8, 14, and 15, when the operation lever 75 is turned to move from the restriction position to the release position, the primary transfer roll 20 is moved away from the photosensitive drum 14 in conjunction with the operation lever 75. The tension adjusting roll 34 moves to the inner side of the intermediate transfer belt 19 and moves to the tension relaxation position where the tension applied to the intermediate transfer belt 19 is relaxed. And it fixes in this position.

  Then, when fixed in the state of FIG. 14, the intermediate transfer belt 19 is separated from the photosensitive drum 14 as indicated by a dotted line in the drawing. Therefore, even if the photosensitive unit 60 is pulled out and inserted (detached), the photosensitive drum 14 and the intermediate transfer belt 19 are not rubbed, so that the photosensitive drum 14 and the intermediate transfer belt 19 are not damaged.

  When the operation lever 75 is turned to move from the release position to the restriction position, the primary transfer roll 20 moves to a contact position where the intermediate transfer belt 19 contacts the photosensitive drum 14 and the tension adjustment roll 34 is interlocked. The movement to move to the tension applying position for applying tension to the intermediate transfer bell 19 is the reverse of the above-described movement.

  Then, as described above and as shown in FIG. 16, the roller 82 of the photosensitive unit 60 is engaged with the recess 85 of the operation lever 75, and the operation lever 75 is locked at the restriction position, so that the entire interlocking mechanism is locked. To do.

  In the above-described configuration, in the color multifunction peripheral according to this embodiment, it is possible to easily replace the image carrier such as the photosensitive drum as follows, as well as the photosensitive drum and the like. Even when the image carrier is replaced, it is possible to prevent image registration from deteriorating and image quality from deteriorating.

  That is, in the color multifunction peripheral according to this embodiment, as shown in FIGS. 2 and 3, when the image forming operation is executed for a long time and the photosensitive drum 14 reaches the end of its life, as shown in FIG. In addition, the user performs an operation of removing the photoconductor unit 60 from the color MFP main body 1 and replacing it with a new photoconductor unit 60.

  At that time, as shown in FIG. 7, the user rotates the operating lever 75 from the restricting position to the releasing position shown in FIG. The tension is relieved and the intermediate transfer belt 19 is separated from the surface of the photosensitive drum 14 together with the primary transfer roll 20.

  Thereafter, as shown in FIG. 4, the user holds the front side panel 63 of the photoconductor unit 60 by hand and pulls it out toward the front, and also holds the handle H provided on the photoconductor unit 60 by hand. The color MFP body 1 is taken out.

  Similarly, as shown in FIG. 4, the user holds the handle H of the new photoconductor unit 60 with his hand and inserts it into a predetermined position of the color MFP main body 1 as shown in FIG. Then, the operating lever 75 is rotated from the release position shown in FIG. 14 to the restricting position as shown in FIGS. 7 and 8, thereby applying tension to the intermediate transfer belt 19 and moving the primary transfer roll 20 to the intermediate position. The surface of the photosensitive drum 14 is brought into contact with the transfer belt 19.

  At this time, when the operation lever 75 is rotated from the release position shown in FIG. 14 to the restriction position as shown in FIGS. 7 and 8, the rotating shaft 86 to which the operation lever 75 is attached rotates counterclockwise. Then, the cam 87 and the contact portion 90 attached to the rotating shaft 86 rotate. Then, as shown in FIG. 8, the convex portion 88 of the cam 87 engages with the concave portion 89 of the second arm 82 to push down the second arm 82 and is attached to the second arm 82. The primary transfer roll 20 is brought into contact with the surface of the photosensitive drum 14 via the intermediate transfer belt 19.

  At the same time, as shown in FIG. 8, the contact portion 90 attached to the rotating shaft 86 pushes the cam 80 so that the stud 92 attached to the second arm 82 While moving over the corner 80D from 80C and moving to the slope 80B, the first arm 76 is rotated in the direction of the arrow R1 by the cam portion 80 via the connecting arm 79. The tension is applied to the intermediate transfer belt 19 by the attached tension adjusting roll 34.

  Further, the operation lever 75 is rotated from the release position shown in FIG. 17 (a) to the regulation position shown in FIG. 17 (c) through the state shown in FIG. 17 (b), as shown in FIG. In this manner, the protrusion 113 of the stopper 111 provided on the side panel 63 on the front side of the photoreceptor unit 60 is stopped in a pressed state, and the photoreceptor spring 60 has a coil spring 110 built in the stopper 111. Preload is applied by the repulsive force.

  Therefore, in the above-described color multifunction peripheral, as shown in FIG. 1, four developments of yellow (Y), magenta (M), cyan (C), and black (K) of the rotary developing device 16 are performed in the image forming state. Among the developing devices 16Y, 16M, 16C and 16K, as shown in FIG. 1, the developing device of a predetermined color moves to the developing position facing the photosensitive drum 14 and stops, and the developing roller 17 of the developing device 17 Even when a force F acts as a disturbance on the photosensitive drum 14 via the tracking rolls 73 and 74 provided at both ends, the photosensitive drum unit 60 has a coil spring 110 built in the stopper 111. Preload is applied, and the front side panel 63 of the photoconductor unit 60 is provided with the regulating members 114, 1 provided on the front side panel 101 of the color MFP main body 1. Since contact with a 5 is restricted, it is not the photosensitive drum 14 moves along the axial direction.

  Therefore, when developing electrostatic latent images of yellow (Y), magenta (M), cyan (C), and black (K) that are sequentially formed on the surface of the photosensitive drum 14, the photosensitive drum 14 is developed. Since the position of the photosensitive drum 14 is always constant, there is no occurrence of skew or displacement, and the photosensitive drum 14 can be easily replaced. However, it is possible to prevent deterioration in image registration due to image registration deterioration.

Embodiment 2
FIG. 18 shows a second embodiment of the present invention. The same parts as those in the first embodiment will be described with the same reference numerals. In the second embodiment, the image carrier unit will be described. And a second preload applying member that applies preload in a direction orthogonal to the axial direction.

That is, in the second embodiment, as shown in FIG. 18, when the operation lever 75 is rotated to the restricting position, a preload is applied to the photosensitive drum 14 in a direction orthogonal to the axial direction, that is, on the developing device side. The second preload applying member 120 to be applied is provided.
The second preload applying member 120 is composed of eccentric cams 121 and 122 attached to the rotation shaft 86 of the operation lever 75. When the operation lever 75 is rotated to the restriction position, the cam 121, A preload is applied by 122 to urge the photosensitive unit 60 toward the developing device.

  With this configuration, when developing an electrostatic latent image of each color of yellow (Y), magenta (M), cyan (C), and black (K) sequentially formed on the surface of the photosensitive drum 14. In addition, the position of the photoconductive drum 14 is always constant, and the photoconductive drum 14 can be easily replaced without causing any skew or misalignment. Even in the case of replacement, it is possible to more reliably prevent image registration from deteriorating and image quality from deteriorating.

  Since other configurations and operations are the same as those of the above-described embodiment, description thereof is omitted.

  In the first embodiment, the case where the stopper 111 biased in the direction protruding by the coil spring 110 as the biasing member is used as the preload imparting member has been described. However, the present invention is not limited to this, and a projection projecting toward the operation lever 75 is provided on the photoconductor unit 60, and when the operation lever 75 is rotated to the restriction position, the operation lever 75 is elastically deformed into a bent state. Thus, a preload may be applied to the photoconductor unit 60. In this case, the coil spring 110 becomes unnecessary, the number of parts can be reduced, and the cost can be reduced.

FIG. 1 is a cross-sectional view showing the main part of a “4-cycle” type color multifunction peripheral as an image forming apparatus according to Embodiment 1 of the present invention. FIG. 2 is a block diagram showing a “4-cycle” type color multifunction peripheral as an image forming apparatus according to Embodiment 1 of the present invention. FIG. 3 is a block diagram showing an image forming unit of a “4-cycle” type color multifunction peripheral as an image forming apparatus according to Embodiment 1 of the present invention. FIG. 4 is a perspective configuration diagram showing an operation of attaching / detaching the photosensitive unit to / from the color multifunction device main body. FIG. 5 is a perspective configuration diagram showing the photosensitive unit. FIG. 6 is a rear perspective view showing a structure for mounting the photosensitive unit to the main body of the color MFP. FIG. 7 is a perspective configuration diagram showing a mechanism for attaching and detaching the intermediate transfer belt to and from the color multifunction printer main body. FIG. 8 is a front configuration diagram showing a mechanism for attaching and detaching the intermediate transfer belt to and from the color multifunction machine main body. FIG. 9 is a perspective configuration diagram showing a mechanism for attaching and detaching the intermediate transfer belt to and from the color multifunction peripheral body. FIG. 10 is a cross-sectional configuration diagram illustrating a configuration in which the intermediate transfer belt is attached to and detached from the color MFP main body. FIG. 11 is a schematic configuration diagram showing a mechanism for applying a preload to the roller. FIG. 12 is a cross-sectional configuration diagram illustrating a state in which the intermediate transfer belt is detached from the color MFP main body. FIG. 13 is a rear perspective view showing the operation lever. FIG. 14 is a front structural view showing a mechanism for attaching / detaching the intermediate transfer belt to / from the color multifunction machine main body. FIG. 15 is a front configuration diagram showing a mechanism for attaching and detaching the intermediate transfer belt to and from the color multifunction printer main body. FIG. 16 is a cross-sectional view showing the main part of a “4-cycle” type color multifunction peripheral as an image forming apparatus according to Embodiment 1 of the present invention. FIG. 17 is an explanatory diagram showing an operation for mounting the photosensitive unit to the color multifunction printer main body. FIG. 18 is a cross-sectional configuration diagram showing a main part of a “4-cycle” type color multifunction peripheral as an image forming apparatus according to Embodiment 2 of the present invention. FIG. 19 is an explanatory view showing the operation of attaching and detaching the photosensitive unit in the conventional image forming apparatus. FIG. 20 is a cross-sectional configuration diagram illustrating a structure for attaching and detaching a photosensitive unit in a conventional image forming apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1: Color compound machine main body, 14: Photoconductor drum, 19: Intermediate transfer belt, 60: Photoconductor unit, 75: Operation lever, 110: Coil spring, 111: Stopper (preload application member).

Claims (3)

An image carrier unit including at least an image carrier on which a toner image is formed, and an intermediate transfer belt to which a toner image formed on the image carrier is transferred, the image carrier unit comprising: In the image forming apparatus configured to be detachable from the image forming apparatus main body along the axial direction of
A tensioning mechanism that can be switched between a tension applying position where tension is applied to the intermediate transfer belt, and a tension relaxation position where tension is relaxed;
A contact member that moves the intermediate transfer belt to a contact position that contacts the image carrier and a spaced position that is separated from the image carrier in conjunction with the switching operation of the stretching mechanism;
An operation member for performing an operation of switching the tension mechanism between a tension applying position and a tension relaxation position;
An image forming system comprising: a preload applying member that applies a preload that stops movement along the axial direction to the image carrier unit in conjunction with an operation of switching the operation member to a tension applying position. apparatus. 2. The tension mechanism includes a mechanism for moving a tension adjusting roll among a plurality of rolls that stretch the intermediate transfer belt to a tension applying position and a tension relaxation position. The image forming apparatus described. The image forming apparatus according to claim 1, further comprising a second preload applying member that applies a preload to the image carrier unit in a direction orthogonal to the axial direction.

Images