JP5618249B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus.

  Patent Document 1 has a transfer belt for transferring a toner image on a photosensitive member and a secondary transfer unit for transferring the toner image on the transfer belt to a recording medium, and detects a reference toner image on the transfer belt. A configuration is disclosed in which a shutter for protecting the detection surface of the optical sensor is provided in the optical sensor, and the shutter is separated from the transfer belt when the secondary transfer unit is pulled out from the apparatus main body.

JP 2009-168888 A

  An object of the present invention is to provide an image forming apparatus capable of preventing the transfer belt from being damaged.

  In order to achieve the above object, the present invention according to claim 1 includes an image forming apparatus main body and a belt-shaped conveying member for conveying a developer image, and is detachably provided to the image forming apparatus main body. The image forming apparatus includes: a transport device; and a pressing unit that presses the transport member when the transport device is detached from the image forming apparatus main body.

  The present invention according to claim 2 is the image forming apparatus according to claim 1, wherein the pressing means presses at least both end portions orthogonal to the moving direction of the conveying member.

  The present invention according to claim 3 further includes transfer means for transferring the developer image conveyed by the conveying member to a recording medium, and guide means for guiding the recording medium to the transfer means, and the pressing means. The image forming apparatus according to claim 1, wherein the image forming apparatus includes a part of the guide unit.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect, the guide unit includes two guide plates opposed to each other, and the pressing unit includes one of the two guide plates. It is.

  According to a fifth aspect of the present invention, the guide unit further includes a biasing unit that biases the pressing unit in a direction of pressing the transporting member when the transporting device is detached from the image forming apparatus main body. The image forming apparatus according to 3 or 4.

  According to the first aspect of the present invention, an image forming apparatus capable of preventing the transfer belt from being damaged can be provided.

  According to the second aspect of the present invention, in addition to the effect of the first aspect of the present invention, a simple configuration can be achieved as compared with the case where the present configuration is not provided.

  According to the third aspect of the present invention, in addition to the effect of the present invention according to the first or second aspect, the number of parts can be reduced as compared with the case where the present configuration is not provided.

  According to the fourth aspect of the present invention, in addition to the effect of the present invention according to the third aspect, the recording medium can be rapidly conveyed as compared with the case where the present configuration is not provided.

  According to the fifth aspect of the present invention, in addition to the effect of the present invention according to the third or fourth aspect, a simpler configuration can be achieved as compared with the case where the present configuration is not provided.

1 is a side view illustrating an image forming apparatus 10 according to an embodiment of the present invention. It is the figure which looked at the upper chute periphery used for embodiment which concerns on this invention from the side. FIG. 6 is a view of the periphery of the upper chute used in the embodiment according to the present invention as viewed from the inside of the intermediate transfer belt. It is a perspective view of the upper chute used for the embodiment concerning the present invention. (A) of the upper chute used for the embodiment concerning the present invention is a side view, and (b) is a top view. It is a figure explaining operation | movement of each unit of the image forming apparatus 10 of one Embodiment of this invention. It is a figure which shows operation | movement of the top chute | shoot used for embodiment of this invention. FIG. 4 is a diagram illustrating a state of an intermediate transfer belt around a backup roll.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an outline of an image forming apparatus 10 according to an embodiment of the present invention. The image forming apparatus 10 includes an image forming apparatus main body 12, an image forming unit 14 is mounted in the image forming apparatus main body 12, and a transport unit 16 is provided below the image forming unit 14. For example, two-stage sheet feeding devices 18 and 18 are disposed below the image forming apparatus main body 12.

  Each sheet feeding device 18 includes a sheet feeding cassette 22 in which sheets S are stacked and stored. Here, the sheet S may be in any form as long as it is sheet-shaped, and the material is not limited. In the embodiment of the present invention, a sheet which is a recording medium will be described as an example of a typical aspect of a sheet. A pickup roll 24 is disposed in the upper part near the rear end of the paper feed cassette 22, and a pinch roll 26 and a conveyance roll 28 are disposed downstream of the pickup roll 24 in the sheet conveyance direction. The pickup roll 24, the pinch roll 26, and the transport roll 28 may be provided in the image forming apparatus main body 12 or in the paper feed cassette 22.

  A conveyance path 32, which is the conveyance unit 16, is a sheet path from the conveyance roll 28 to the discharge port 34, and the conveyance path 32 is in the vicinity of the side portion (left side surface in FIG. 1) of the image forming apparatus main body 12. A portion is formed substantially horizontally from the lowermost sheet feeding device 18 to a fixing device 36 described later. For example, three conveyance belts 37 are disposed on the upstream side of the conveyance path 32 in the sheet conveyance direction of the fixing device 36, and a secondary transfer device 42 serving as a transfer unit is disposed on the upstream side of the conveyance belt 37, and further secondary transfer is performed. An upper chute 88 and a lower chute 90, which will be described later, are arranged on the upstream side of the apparatus 42, and a resist roll 38 is arranged on the further upstream side. The registration roll 38 is a temporary stop member that temporarily stops the sheet conveyed by the paper supply device 18. Further, a discharge roll 40 is disposed in the vicinity of the discharge port 34 of the conveyance path 32.

  Therefore, the sheet S sent out from the paper feed cassette 22 of the paper feeding device 18 by the pickup roll 24 is turned by the cooperation of the pinch roll 26 and the transport roll 28, and only the uppermost sheet is guided to the transport path 32. The developer image is temporarily stopped by the roll 38 and passes between the upper chute 88 and the lower chute 90 with timing, and the developer image passes between the secondary transfer roll 80 and the backup roll 76 which are the secondary transfer device 42. The transferred developer image is transferred and transported by a transport belt 37, and is fixed by a fixing device 36, and is discharged from a discharge port 34 by a discharge roll 40.

  The image forming unit 14 is, for example, of an electrophotographic system, and includes four image holding bodies 44a to 44d made of a photosensitive member, and charging devices 56a to 56d made of, for example, charging rolls that charge the image holding bodies 44a to 44d, Exposure devices 58a to 58d for writing a latent image on the image holding members 44a to 44d charged by the charging devices 56a to 56d, and latent images of the image holding members 44a to 44d formed by the exposure devices 58a to 58d. Developing devices 60a to 60d that are visualized by a developer, primary transfer devices (primary transfer rolls) 61a to 61d that primarily transfer a developer image by the developing devices 60a to 60d to the sheet S, and image carriers 44a to 44d. The secondary transfer is performed by the secondary transfer device 42 and the cleaning devices 62a to 62d made of, for example, blades for cleaning the developer to be cleaned. The developer image on the sheet S and a fixing device 36. for fixing on the sheet S has.

  An intermediate transfer belt 70 that is a belt-shaped conveying member is stretched around tension rolls 72 a to 72 c, a drive roll 74, and a backup roll 76, and intermediate transfer is performed by the tension rolls 72 a to 72 c, the drive roll 74, and the backup roll 76. The belt 70 can move in the direction of arrow A between the image carriers 44a to 44d and the primary transfer rollers 61a to 61d while being in contact with the surfaces of the image carriers 44a to 44d. A portion where the primary transfer rolls 61a to 61d come into contact with the image holding bodies 44a to 44d via the intermediate transfer belt 70 becomes a primary transfer portion, and a primary contact portion between the image holding bodies 44a to 44d and the primary transfer rolls 61a to 61d is a primary transfer portion. A transfer voltage is applied.

  Further, as the secondary transfer device 42, a backup roll 76 and a secondary transfer roll 80 are disposed to face each other with an intermediate transfer belt 70 and a secondary transfer belt 78 interposed therebetween. The sheet S moves in the direction of arrow B between the intermediate transfer belt 70 and the secondary transfer roll 80 while contacting the surface of the intermediate transfer belt 70, and then passes through the fixing device 36. A portion where the secondary transfer roll 80 comes into contact with the backup roll 76 via the intermediate transfer belt 70 and the secondary transfer belt 78 becomes a secondary transfer portion. A transfer voltage is applied. Further, an intermediate transfer belt cleaning device 82 is disposed so as to come into contact with the intermediate transfer belt 70 after transfer.

  In the full-color image forming apparatus 10 having such a configuration, the image carrier 44a rotates in the direction of the arrow, and the surface thereof is uniformly charged by the charging device 56a, and then the first color is applied by the exposure device 58a such as laser light. Electrostatic latent image is formed. The formed electrostatic latent image is developed with toner by a developing device 60a containing toner corresponding to the color to form a toner image. The developing devices 60a to 60d contain toners (for example, yellow, magenta, cyan, and black) corresponding to the electrostatic latent images of the respective colors.

  The toner image formed on the image carrier 44a is electrostatically transferred (primary transfer) onto the intermediate transfer belt 70 by the primary transfer roll 61a when passing through the primary transfer portion. Thereafter, the first, second, third, and fourth color toner images are primarily transferred onto the intermediate transfer belt 70 holding the first color toner image by the primary transfer rolls 61b to 61d so that the toner images of the second color, the third color, and the fourth color are sequentially superimposed. Thus, a full color multiple toner image can be obtained.

  The multiple toner images formed on the intermediate transfer belt 70 are electrostatically collectively transferred onto the sheet S when passing through the secondary transfer portion. The sheet S on which the laminated toner image is transferred is conveyed to the fixing device 36 by the conveying belt 37, subjected to fixing processing by heating and pressing, and then discharged outside the apparatus.

  The residual toner is removed from the image carriers 44a to 44d after the primary transfer by the cleaning devices 62a to 62d. On the other hand, the residual toner is removed from the intermediate transfer belt 70 after the secondary transfer by the cleaning device 82 to prepare for the next image forming process.

  The control unit 30 is disposed in the image forming apparatus main body 12 and controls each part constituting the image forming apparatus 10.

2 is a view of the periphery of the upper chute 88 as viewed from the side, and FIG. 3 is a view of the periphery of the upper chute 88 as viewed from the inside of the intermediate transfer belt 70.
The upper chute 88 is an upper guide plate that guides the sheet S between the backup roll 76 serving as a transfer unit and the secondary transfer roll 80.
Further, below the upper chute 88, a lower chute 90 as a lower guide plate that guides the sheet S between the backup roll 76 serving as transfer means and the secondary transfer roll 80 is disposed so as to face. Accordingly, a secondary transfer roll 80 and a backup roll 76 as transfer means are arranged on the downstream side of the upper chute 88 and the lower chute 90 in the sheet conveying direction, and a registration roll 38 is arranged on the upstream side. Further, the upper chute 88 and the lower chute 90 are arranged such that the gap between the chute is wide on the upstream side in the sheet conveying direction and the gap between the chute becomes narrower as it is conveyed between the backup roll 76 and the secondary transfer roll 80. The upper chute 88 is longer than the width of the intermediate transfer belt 70 and extends in a direction orthogonal to the sheet conveying direction.
That is, the sheet S conveyed from the sheet feeding device 18 is conveyed to a plurality of conveyance rolls, temporarily stopped by the registration roll 38, passes between the upper chute 88 and the lower chute 90, and the secondary roll and the secondary roll 76. It is conveyed between the transfer rolls 80.

Next, the upper chute 88 used in this embodiment will be described.
4 shows a perspective view of the upper chute 88, FIG. 5 shows a side view and (b) a top view of the upper chute 88. FIG.
The upper chute 88 is formed of a first guide surface 88a on the upstream side in the sheet conveying direction and a second guide surface 88b connected to the downstream side of the first guide surface 88a in the sheet conveying direction. The first guide surface 88a is inclined and connected to the second guide surface 88b.
A semicircular protection portion 88c is formed at the tip of both side surfaces of the first guide surface 88a. In addition, a pressing member 92 that is a pressing means is provided in the vicinity of the protective portion 88c on the upper surface of the first guide surface 88a. The pressing member 92 is disposed outside the image forming area of the intermediate transfer belt 70.
The pressing member 92 has a curved upper surface (a surface in contact with the intermediate transfer belt 70). That is, even if the pressing member 92 presses the intermediate transfer belt 70, the intermediate transfer belt 70 is not damaged.
The second guide surface 88b has an end opposite to the first guide surface 88a formed in an oblique shape with respect to the sheet conveying direction. As a result, the sheet S is gradually pulled out from between the chutes to reduce the rebound of the sheet S. A protrusion 88d is formed at the end of the second guide surface 88b opposite to the first guide surface 88a and on the shortest side in the sheet conveying direction. Further, support portions 88f are formed substantially perpendicularly from the second guide surface 88b on both side surfaces of the second guide surface 88b in the vicinity of the joint surface with the first guide surface 88a. A hole 88e is formed in the support portion 88f, and the upper chute 88 is rotated by a support shaft inserted into the holes 88e and 88e. In addition, for example, a spring 94 as an urging means is provided on the support shaft inserted into the hole 88e. The spring 94 is compressed by bringing both ends of the spring 94 close to each other.

Next, the operation of each unit of the image forming apparatus 10 according to the present embodiment will be described with reference to FIG.
The image forming apparatus 10 includes an image forming apparatus main body 12 to which a resist roll 38 and the like are mounted, image holders 44a to 44d, charging devices 56a to 56d, exposure devices 58a to 58d, developing devices 60a to 60d, and a primary transfer device 61a. ˜61d and the intermediate transfer belt 70, etc., a transport unit 84 as a transport device for transporting the developer image, and a transfer unit 86, as a transfer device, including the secondary transfer roll 80, the secondary transfer belt 78, the transport belt 37, and the like. It is composed of
When performing maintenance, first, the transfer unit 86 is lowered downward in the direction of gravity (see FIG. 6B). The transport unit 84 can be pulled out of the apparatus main body 12 and the transfer unit 86 can be pulled out of the apparatus main body 12 (see FIG. 6C), and maintenance such as replacement of the apparatus of each unit can be performed.
Here, the upper chute 88 is disposed in the transport unit 84, and the lower chute 90 is disposed in the transfer unit 86.

The operation of the upper chute 88 according to the operation of each unit of the image forming apparatus 10 according to the present embodiment will be described with reference to FIG.
FIG. 7A shows the state of the upper chute 88 when the apparatus is movable (when the intermediate transfer belt is running), and FIG. 7B shows the state of the upper chute 88 during maintenance (when the intermediate transfer belt is stopped).
As the intermediate transfer belt 70 continues to be used, as shown in FIG. 8, when the tension of the intermediate transfer belt acts, scratches 95 are formed near both ends. Thereby, both ends will warp. This warping is not an image problem, but when the transport unit 84 is taken out during the above-mentioned maintenance, both ends of the warped intermediate transfer belt 70 interfere with the frame or the like, leading to damage to the intermediate transfer belt.
In this embodiment, as shown in FIGS. 6A and 7A, when the apparatus is movable, the second guide surface 88b and the protrusion 88d of the upper chute 88 are forced in the direction in which they are pushed up from the transfer unit 86. In response, the spring 94 acts in a compressing direction against the urging force, and the tip of the upper chute 88 is lowered. That is, the pressing member 92 is separated from the intermediate transfer belt 70.
Then, as shown in FIGS. 6B, 6C, and 7B, at the time of maintenance, the transfer unit 86 is lowered and the conveying unit 84 is separated from the transfer unit 86. A force acts in a direction in which the urging force is released (a direction in which both ends of the spring 94 are opened), and the tip of the upper chute 88 is raised. That is, the pressing member 92 contacts the intermediate transfer belt 70 and presses both ends of the intermediate transfer belt 70 in the direction of arrow C in FIG. This prevents the end of the warped intermediate transfer belt from being damaged due to interference with the frame or the like.

  In the present embodiment, the example in which the pressing member that presses the transfer belt at the time of maintenance is provided on the upper chute 88 has been described. However, the present invention is not limited to this and may be provided on another member.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Apparatus main body 36 Fixing apparatus 38 Registration roll 42 Secondary transfer apparatus 44a-44d Image holding body 56a-56d Charging apparatus 58a-58d Exposure apparatus 60a-60d Development apparatus 61a-61d Primary transfer apparatus (primary transfer roll)
70 Intermediate transfer belt 76 Backup roll 80 Secondary transfer roll 84 Conveyance unit 86 Transfer unit 88 Upper chute (upper guide plate)
90 Lower chute (lower guide plate)
92 Holding member 94 Spring (biasing member)

Claims (5)

An image forming apparatus main body;
A transport device having a belt- shaped transfer belt for transporting a developer image;
If the carrying device is removed from the image forming apparatus main body, have a, a pressing portion that presses at two different places at least axially the transfer belt,
The pressing portion is an image forming apparatus in which a surface in contact with the transfer belt is a curved surface convex toward the transfer belt . The image forming apparatus according to claim 1, wherein the pressing portion presses at least both end portions orthogonal to the moving direction of the transfer belt . The image forming apparatus further includes: a transfer portion that transfers the developer image conveyed by the transfer belt to a recording medium; and a guide member that guides the recording medium to the transfer portion , and the pressing portion is provided in the guide member. Item 3. The image forming apparatus according to Item 1 or 2. The image forming apparatus according to claim 3, wherein the guide member is configured by two guide plates facing each other, and the pressing portion is configured by one of the two guide plates. The image forming apparatus according to claim 3, wherein the guide member further includes a biasing member that biases the pressing unit in a direction of pressing the transfer belt when the transport device is detached from the image forming apparatus main body.

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