JP4547217B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus having a unit that is detachably mounted in an apparatus main body.

  In copiers, printers, facsimiles, and image forming apparatuses having at least two of these functions, one or more of the members that perform image formation are unitized into the apparatus main body for jam paper processing, maintenance, and member replacement. Many of them are detachably attached. There are various members that can be attached and detached as a unit, and an image carrier belt unit such as an intermediate transfer belt of a color image forming apparatus is one of them.

Japanese Patent Laid-Open No. 2001-134096 JP 2000-275987 A

  In general, when attaching and detaching a belt unit, many are guided from a guide rail and operated from the front-rear direction of the apparatus main body, which is disclosed in Patent Document 1, for example. Further, Patent Document 2 discloses an image forming apparatus in which when the belt unit to be pulled out is an intermediate transfer belt, the belt unit is pulled out while being moved away from the image forming unit of each color.

  As described above, in the image forming apparatus in which the belt unit can be pulled out and taken out, it is necessary to prevent the belt unit from being accidentally pulled by a large force when being pulled out and falling from the guide portion.

  An object of the present invention is to provide an image forming apparatus capable of preventing a unit from dropping and easily taking out the unit from the apparatus main body.

In order to achieve the above object, according to the present invention, in an image forming apparatus having a unit that can be removed from the apparatus main body , the image forming apparatus includes a guide member that guides movement of the unit in the removal direction. In the apparatus main body, an apparatus main body guide section for guiding the unit when the apparatus is in the apparatus main body, an inclined section for shifting the unit upward, and a horizontal section for guiding the shifted unit are sequentially provided in the unit take-out direction. The unit is provided with a blocking member that, when the unit is taken out to the position guided by the horizontal portion, blocks the movement of the picking-up direction by striking the apparatus main body, It is possible to release the blocking from the state of striking the device main body to the state of not striking the device, and the horizontal part hits the device main body. It is characterized by being at least provided in a position of the unit the take-out direction front side than the position of the blocking member.

The present invention is effective when image formation is possible in a state where the unit is in the apparatus main body and is guided by the guide portion in the apparatus main body .

Further, according to the present invention, the unit is provided with a second blocking member that is capable of releasing the blocking from a state in which it hits the apparatus main body to a state in which it does not hit, on the near side of the unit removal direction from the blocking member. The second blocking member abuts against the apparatus main body when the unit is moved toward the apparatus main body to block the movement into the apparatus main body, and the second blocking member is configured to block the second blocking member when the blocking member is in the blocking state. It is effective to take the blocking release state and the blocking state when the blocking member is in the blocking release state .

Furthermore, the present invention is effective when it has a support shaft that rotatably supports the blocking member and the second blocking member .
Furthermore, the present invention is effective when the second blocking member has a handle .

Furthermore, the present invention is effective when the blocking member and the second blocking member are provided on the upper surface of the unit .
Furthermore, the present invention is effective when the support shaft is provided in parallel with the unit removal direction .

Furthermore, the present invention is effective when the support shaft is a square axis having a square cross section with rounded corners.
Furthermore, the present invention is effective when the set of the blocking member and the second blocking member is provided one by one at different positions in the direction orthogonal to the unit removal direction.
Furthermore, the present invention is effective when the unit has a belt stretched around a plurality of rollers.

Furthermore, the present invention is effective when the unit has an image carrier that carries a toner image .
Furthermore, the present invention is effective when the unit includes an intermediate transfer belt that carries the toner image transferred from the image carrier, and the image carrier is disposed below the intermediate transfer belt .

According to the present invention , it is possible to prevent the unit from dropping due to excessive movement, and when the movement is blocked by the blocking member, the unit is in a horizontal state, so that the unit can be prevented from returning backward along the inclined portion. It is possible to easily move the member between the blocking position and the blocking release position.

  According to the configuration of the second aspect, the blocking member is movable between the blocking position where the blocking member stands up and hits the frame of the apparatus main body and the blocking release position where the blocking member does not hit the frame body. And the blocking release position can be easily performed.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic view showing a color laser printer which is an example of an image forming apparatus according to the present invention.

  In FIG. 1, an intermediate transfer belt 11 stretched between support rollers 12 and 13 is disposed in the lateral direction at substantially the center of the apparatus main body. Four image forming units SU are juxtaposed along the lower running side of the intermediate transfer belt 11. The image forming unit SU is a unit in which equipment necessary for an electrophotographic process, such as a cleaning unit 2, a neutralizing unit 3, a charging unit 4, and a developing unit 5, are arranged around the photosensitive drum 1 as a center. Each image forming unit SU (a, b, c, d) has the same configuration, except that the toner colors handled by the developing unit 5 are magenta, cyan, yellow, and black, respectively.

  An exposure device 6 is disposed below the image forming unit SU. The exposure apparatus 6 of this example is a known laser system, and forms a latent image by irradiating the surface of the photoreceptor with writing light corresponding to each color image information. An exposure apparatus comprising an LED array and an image forming means can also be employed.

  The intermediate transfer belt 11 is a belt based on a resin film or rubber having a thickness of 50 to 600 μm, and has a resistance value capable of transferring toner from the photoreceptor 1. The intermediate transfer belt 11 is rotated counterclockwise in the drawing by a driving roller 11 connected to a driving means (not shown). On the back side of the surface of the intermediate transfer belt 11 that is in contact with the photoreceptor 1, a transfer roller 14 that is a primary transfer unit is disposed to face the photoreceptor 1. These intermediate transfer belt 11, support rollers 12, 13 and transfer roller 14 can be detachably attached to the image forming apparatus main body as an intermediate transfer unit 10.

  A cleaning device 15 having a cleaning blade 16 as a cleaning member is disposed outside the belt loop and facing the support roller 13, and wipes unnecessary toner and paper dust remaining on the surface of the intermediate transfer belt 11. leave. The cleaning device 25 can also be configured to be detachable from the image forming apparatus main body integrally with the intermediate transfer unit 10. The mechanism and method for attaching / detaching the intermediate transfer unit 10 will be described in detail later.

  In FIG. 1, a conveyance belt 30 is stretched in the vertical direction on the right side of the intermediate transfer belt 11. The conveyor belt 30 is wound around support rollers 31 and 32, and the support roller 31 is driven by a driving means (not shown) to be rotated clockwise in the drawing. On the back side (inside the loop) of the conveyance belt 30, a transfer roller 33 as a secondary transfer unit that transfers a toner image carried on the intermediate transfer belt 11 to a recording medium is opposed to the roller 12 that supports the intermediate transfer belt 11. Has been deployed. In addition, a cleaning device 35 for the conveyor belt 30 is disposed outside the loop of the conveyor belt 30. The cleaning device 35 includes a collection unit 34, removes unnecessary toner remaining on the transfer / conveyance belt device 100 after the toner is transferred to the paper, and sends the removed toner and the like to the collection unit 34. At a position where the conveyance belt 30 contacts the intermediate transfer belt 11, a predetermined transfer nip is formed by the secondary transfer roller 333 and the support roller 12.

  The two-stage sheet cassettes 26-1 and 26-2 provided in the sheet feeding unit store sheets P as recording media, and the uppermost sheet is fed by a feeding unit including a sheet feeding roller 27. The fed paper is guided by a plurality of guide members 29 and 25 and conveyed to the registration roller pair 28.

  A fixing device 36 having a built-in heat source such as a heater is provided above the conveyance belt 30, and a paper discharge guide 37 and a paper discharge roller pair 38 are arranged following the fixing device 36. A part of the frame 40 of the main body on which the conveying belt 30 is disposed has a structure that can be rotated and opened around the opening / closing support shaft 24. When the paper P is jammed, the paper conveying path is greatly opened. , Making it easier to handle jammed paper.

  The upper surface of the image forming apparatus main body is configured as a paper discharge stack unit 39. A storage unit TS in which four toner cartridges TC storing replenishment toner can be set is provided below the paper discharge stack unit 39 and above the intermediate transfer belt 11. The toner cartridge TC has four toner colors, magenta, cyan, yellow, and black, and is supplied to the corresponding developing device 5 by a powder pump (not shown).

An image forming operation in the image forming apparatus configured as described above will be described.
The image forming apparatus of this example is a so-called printer, and a signal for writing is sent from a host machine, for example, a computer. The exposure device 6 is driven based on the received image signal, and light from a laser light source (not shown) of the exposure device is scanned by a polygon mirror that is rotationally driven by a motor. The uniformly charged photosensitive drum 1 is irradiated, and a latent image corresponding to writing information (color-separated color image information) is formed on the photosensitive member 1.

  The latent image formed on the photosensitive drum 1 is developed by the developing device 5 and is formed and held on the surface of the photosensitive drum 1 as a toner image. This toner image is transferred by the primary transfer roller 14 onto the surface of the intermediate transfer belt 11 that moves in synchronization with the photosensitive drum 1. The toner remaining on the surface of the photosensitive drum 1 after the transfer of the toner image is cleaned by the cleaning unit 2, and then the photosensitive drum 1 is discharged by the discharging device 3 to prepare for the next image forming cycle.

  The intermediate transfer belt 11 carries the toner image transferred from the photosensitive drum 5 of the image forming unit a on the surface and moves in the direction of the arrow. A latent image corresponding to another color is written on the photosensitive drum 1 of the image forming unit b, and developed with a toner of the corresponding color to become a toner image. This image is superimposed on the previous color toner image already on the intermediate transfer belt 11, and finally the four color toner images formed by the image forming portions a, b, c, and d are superimposed to obtain a full color. An image is formed. The transport belt 30 also moves in the direction of the arrow so as to be synchronized with the intermediate transfer belt 11.

  When the toner image on the intermediate transfer belt 11 moves to a predetermined position, paper feeding is started. That is, the paper feed roller 27 rotates in the direction of the arrow, and the uppermost paper P in the paper feed cassette 26-1 or 26-2 is pulled out and conveyed to the registration roller pair 28. Then, the sheet is sent out from the registration roller pair 28 at a timing so that the position of the image becomes normal. The toner images superimposed on the four colors on the intermediate transfer belt 11 are transferred onto the one side surface of the paper P sent between the intermediate transfer belt 11 and the conveyance belt 30 at once by the secondary transfer roller 34.

  In this example, the polarity of the electrostatic latent image formed on the surface of the photoconductor drum 1 is positive, and the polarity of the toner formed on the photoconductor is negative. By applying a positive charge larger than the charge of the latent image on the photoconductor 1 to the primary transfer roller 14, the toner held on the photoconductor 1 is transferred to the intermediate transfer belt 11. Further, by applying a positive charge to the secondary transfer roller 34, the toner carried on the intermediate transfer belt 11 is transferred onto the paper P.

The sheet P having the toner image transferred to the surface as described above is sent to the fixing unit 36, where the toner image on the sheet P is fixed, and the sheet P is discharged to the discharge stack unit 39 by the discharge roller pair 38 via the guide 37. Discharged.
When the paper discharge unit 39 is configured as shown in FIG. 1, the image surface is placed on the paper discharge unit 39 with the bottom surface, and page alignment is possible when images are sequentially formed from the first page. After the image is transferred from the intermediate transfer belt 11 to the paper P, unnecessary toner and paper dust are wiped off from the belt surface and collected by a cleaning device 15 provided with a cleaning blade 16 inside.

  Here, the operation of forming an image on only one side of the paper has been described. However, it may be configured such that an image is formed on both sides of the paper by using the transport belt 30 as the second intermediate transfer belt. When forming images on both sides of the paper P, a four-color superimposed toner image as the first image carried on the surface of the intermediate transfer belt 11 is transferred to the second intermediate transfer belt 30 by the secondary transfer roller 34. The Thereafter, while the four-color superposed toner image as the second image is formed on the intermediate transfer belt 11, the first image is carried on the second intermediate transfer belt 30 and conveyed to the transfer position. Timing is measured by the intermediate transfer belt 11, the second intermediate transfer belt 30, and the registration roller pair 28, and the first image and the second image are simultaneously transferred onto both sides of the sheet.

  The sheet P on which the toner images are transferred on both sides is sent to the fixing unit 36, and the images on both sides are fixed on the sheet at the same time, discharged to the sheet discharge unit 39 by the sheet discharge roller pair 38 through the guide 37 and stacked. . Here, the image formation of a color image using a plurality of color toners has been described, but the present invention can also be applied to a monochrome image.

The intermediate transfer unit 10 of the present embodiment is detachable from the apparatus main body, and will be described in detail below.
FIG. 2 is a perspective view showing a frame configuration of the apparatus main body. As shown in this figure, the main body frame as a frame is composed of front and rear face plates 41, 42, a side face plate 43 and a bottom face plate that connect the front and rear face plates. The front plate 41 is provided with two upper and lower openings 41a and 41b. The upper opening 41a is an opening for attaching and detaching the belt unit U to and from the apparatus main body, and the photosensitive member face plate 47 is rotatably mounted and supported on the front face plate 41 so as to open and close the upper opening 41a. The lower opening 41b is an opening for inserting and removing the paper feeding cassettes 26-1 and 26-2.

  A drive unit 48 is attached to the rear plate 42. The driving unit 48 includes a driving mechanism such as a motor and a gear train for driving the photosensitive drum 1 and the developing device 5 or the driving roller of the intermediate transfer belt 11 in each image forming unit SU.

  FIG. 3 is an explanatory view showing an aspect when the intermediate transfer unit 10 is taken out. The intermediate transfer unit 10 is supported by a guide rail 45 as a guide member, and is detachable from the apparatus main body. Although not shown, the guide rails 45 are provided on the left and right sides of the intermediate transfer unit 10, respectively. The guide rail 45 has a rear end in contact with or close to the rear plate 42, a front end reaching a position protruding forward from the front plate 41, and the gap between the rear plate 42 and the front plate 41 is horizontal. The intermediate transfer unit 10 is a regular position when it is between the rear plate 42 and the front plate 41, and is a position where image formation is possible. The guide rail 45 is provided with an inclined portion 45a for shifting the unit upward at substantially the position of the front plate 41 in the pulling direction, and further provided with a horizontal portion 45b following the inclined portion 45a. In the present invention, since the guide rail 45 is provided with the inclined portion 45a for shifting the intermediate transfer unit 10 upward, the drawing unit can be shifted in a direction away from the photosensitive member of the image forming unit SU. There is no risk of injury to the body.

  By the way, as described above, if the intermediate transfer unit 10 guided by the guide rail 45 is accidentally pulled out with a large force, the unit may come off the guide rail 45 and fall.

  Therefore, a blocking member 50 is provided on the upper surface of the intermediate transfer unit 10 so as to abut against the inner surface side of the front plate 41 and prevent further drawing when the unit is pulled out to some extent. When the blocking member 50 abuts against the front plate 41, the installation position is set so that the intermediate transfer unit 10 pulled out is positioned on the horizontal portion 45b as shown in FIG. Accordingly, when the intermediate transfer unit 10 is pulled out and the blocking member 50 hits the front plate 41, the intermediate transfer unit 10 does not stop on the inclined portion 45a, so that the stopped intermediate transfer unit 10 moves rearward under its own weight along the inclined portion 45a. There will be no return.

  When the intermediate transfer unit 10 pulled out to the position where the blocking member 50 hits the front plate 41 or close to it is removed from the apparatus main body, the blocking member 50 standing on the unit becomes an obstacle. Therefore, the blocking member 50 of the present embodiment is configured to swing between a movement blocking position where the unit is raised to prevent the unit from being pulled out and a blocking release position along the upper surface of the unit. 51 is fixed. As shown in FIG. 6, the support shaft 51 is a square shaft having a square cross section with rounded corners. A handle 52 as a second blocking member is fixed to the support shaft 51 on the drawing direction side. Yes. The handle 52 is bent along the upper surface of the unit when the blocking member 50 is standing, and is fixed to the support shaft 51 so that when the blocking member 50 is tilted, the handle 52 is raised. Therefore, as shown in FIG. 5, if the handle 52 is raised after the blocking member 50 abuts against the front plate 41, the blocking member 50 falls in conjunction with the handle 52, and the operator holds the handle 52 and holds the intermediate transfer unit. 10 can be easily taken out. It should be noted that the blocking member 50 is stopped with a good unit balance when it hits the front plate 41 at two points rather than one point, and two handles 52 are easier to hold, so the blocking member 50 and the handle 52 are as shown in FIG. It is preferable to provide a pair. In addition, the use of the square shaft as the support shaft 51 is advantageous in stably supporting the standing state because the supporting shaft 51 can be supported by a surface at each of the standing positions of the blocking member 50 and the handle 52. As shown in FIG. 6, by pressing the support shaft 51 with the pressing member 53, the handle 52 does not rotate unless a force of a certain level or more is applied.

  When the intermediate transfer unit 10 is set in the apparatus main body, it is operated by holding the upright handle 52. Since the upright handle 52 is in the movement preventing position, the front plate 41 of the front plate 41 can be mounted even if the unit is to be mounted at a normal position. It cannot be moved further by hitting the outside. At this time, if the handle 52 that is abutted is tilted and rotated to the movement inhibition release position, the unit can be set to the normal position, and the inhibition member 50 rises in conjunction with this rotation. Therefore, it is possible to reliably prevent the blocking member 50 from being set in the blocking release position when the unit is removed next time, and it is possible to reliably prevent the movement from being blocked because the blocking member 50 was not in the blocking position at the time of removal. It can be avoided.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the detachable unit is not limited to the intermediate transfer unit, but may be an image forming unit, an exposure apparatus unit, or a process cartridge including a plurality of image forming members. Further, the interlocking between the blocking member and the second blocking member is most preferable in that the above-described embodiment in which both members are fixed to the rotating shaft is low-cost and reliable interlocking is obtained. If it is difficult to adopt such a configuration due to the conditions, it may be configured to be interlocked with a transmission member such as a gear or using a drive source and a sensor.

1 is a schematic configuration diagram illustrating an overall configuration of an image forming apparatus according to the present invention. It is a perspective view which shows a main body frame. FIG. 3 is an explanatory diagram when an intermediate transfer unit is taken out according to an embodiment of the present invention. FIG. 6 is an explanatory diagram when the intermediate transfer unit is taken out. FIG. 6 is an explanatory diagram when the intermediate transfer unit is mounted. FIG. 4 is an enlarged perspective view illustrating a handle portion of an intermediate transfer unit. It is a perspective view showing an intermediate transfer unit at the time of taking out.

Explanation of symbols

10 Intermediate transfer unit 11 Intermediate transfer belt 41 Front plate 45 Guide rail 45a Inclined portion 45b Horizontal portion 50 Blocking member 51 Support shaft 52 Handle

Claims (12)

In an image forming apparatus having a unit that can be removed from the apparatus body,
A guide member for guiding movement of the unit in the take-out direction;
The guide member includes an apparatus body guide portion that guides the unit when the unit is in the apparatus body, an inclined portion that shifts the unit upward, and a horizontal portion that guides the shifted unit. It is sequentially provided in the take-out direction ,
When the unit is taken out to the position guided by the horizontal part, the unit is provided with a blocking member that abuts against the apparatus main body and prevents movement in the taking-out direction,
The blocking member can be released from blocking from a state where it hits the apparatus main body to a state where it does not hit,
The horizontal portion is provided at least at a position on the near side of the unit removal direction from the position of the blocking member when it hits the apparatus main body.
An image forming apparatus. 2. The image forming apparatus according to claim 1, wherein image formation is possible in a state where the unit is in the apparatus main body and is guided by the guide portion in the apparatus main body. The unit is provided with a second blocking member capable of blocking release from a state of abutting on the apparatus main body to a state of not abutting on the near side of the unit removal direction from the blocking member,
The second blocking member abuts against the apparatus main body when the unit is moved toward the apparatus main body to prevent the movement into the apparatus main body,
The second blocking member takes a blocking release state when the blocking member is in a blocking state and takes a blocking state when the blocking member is in a blocking release state, respectively. Image forming apparatus. The image forming apparatus according to claim 3, further comprising a support shaft that rotatably supports the blocking member and the second blocking member. The image forming apparatus according to claim 3, wherein the second blocking member has a handle. The image forming apparatus according to claim 3, wherein the blocking member and the second blocking member are provided on an upper surface of the unit. The image forming apparatus according to claim 4, wherein the support shaft is provided in parallel to the unit take-out direction. The image forming apparatus according to claim 4, wherein the support shaft is a square axis having a regular square shape with rounded corners. 9. The image forming apparatus according to claim 3, wherein the set of the blocking member and the second blocking member is provided one by one at different positions in a direction orthogonal to the unit take-out direction. The image forming apparatus according to claim 1, wherein the unit includes a belt stretched around a plurality of rollers. The image forming apparatus according to claim 1, wherein the unit includes an image carrier that carries a toner image. The image forming apparatus according to claim 6, wherein the unit includes an intermediate transfer belt that carries a toner image transferred from the image carrier, and the image carrier is disposed below the intermediate transfer belt.

Images