JP2011107253A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device having an inexpensive configuration capable of preventing parts from being damaged during procedures for removing jam and improving workability of the work for removing the jam. <P>SOLUTION: The image forming device is integrally constituted as a transfer fixing unit 9 by letting a paper conveyance guide hold a transfer roller and a fixing means. If the device stops while a paper (not shown) reaches a transfer unit where a photosensitive member 2 and the transfer roller 5 are brought into pressure-contact, an exterior cover 11 is opened to allow the transfer fixing unit 9 to move outside and downward of a device body. Consequently, the transfer roller 5 is separated from the photosensitive member 2, and a transfer nip is released so that the paper (not shown) in the transfer unit can be easily removed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile, and more particularly to a technique related to paper jam processing.

  In an image forming apparatus configured such that a sheet passes under the image forming unit and reaches the fixing unit, when the jam occurs in a state where the sheet reaches the transfer unit, the fixing unit is detached from the image forming apparatus main body. An operation of attaching the fixing means after removing the paper (jamming) can be considered. At this time, an operation of pulling out the sheet sandwiched between the transfer nip portions occurs, and transfer means such as a transfer roller and a transfer belt forming the transfer nip (the sheet non-image surface side rotating body = opposite to the image surface side of the sheet) The sheet is in contact with the image bearing member such as the photosensitive member and the intermediate transfer belt (the sheet image surface side rotating member = the rotating member positioned on the image surface side of the sheet). In this state, the sheet is pulled out, and the image carrier may be damaged. In addition, the paper on the paper transport guide is difficult to grasp and the workability is poor.

  For example, Japanese Patent Application Laid-Open No. 5-197243 discloses a transfer roller, a cleaning unit thereof, a sheet conveyance guide, a fixing unit, and a discharge roller that have exited the transfer unit. Is provided in the transfer fixing unit frame so as to be detachable integrally, and by removing the transfer fixing unit frame, the contact between the photoconductor and the transfer roller is released and the jammed paper can be removed. Yes.

  Japanese Patent Laid-Open No. 4-234057 (Patent Document 2) describes a structure in which a transfer drum and a fixing unit are integrally attached to and detached from the image forming apparatus main body as a transfer fixing cartridge.

  In Japanese Patent Application Laid-Open No. 2004-53987 (Patent Document 3), the fixing unit is configured to be detachable from the main body of the image forming apparatus, and the exterior unit covering the attaching / detaching direction of the fixing unit is fixed integrally with the fixing unit. An image forming apparatus configured as a unit is described.

  However, in the device described in Patent Document 1, the transfer / fixing unit frame is required as a new part, which causes an increase in cost. In addition, since the direction in which the transfer fixing unit frame is attached / detached is the direction in which the photoconductor contacts and separates from the transfer roller, when the transfer fixing unit frame is pulled out in a substantially horizontal direction, the photoconductor and the transfer roller are connected to the transfer fixing unit frame. There is a problem in that the apparatus is not arranged side by side in the vertical direction with respect to the drawing direction but is arranged obliquely, and the apparatus is enlarged accordingly. Furthermore, the direction of attaching and detaching the transfer / fixing unit frame is set to the direction in which the photoconductor comes in contact with and separates from the transfer roller. There is also a problem that the conveyance guide needs to have a complicated shape without being substantially horizontal, which causes a cost increase.

  Further, in the device described in Patent Document 2, a new transfer fixing cartridge housing is provided, and further, a slide rail used for pulling out the transfer fixing cartridge is also provided, which increases costs. There is a problem. In addition, it is described that the transfer drum and the fixing unit have the same lifetime, and the transfer and fixing cartridge must be replaced at the time of replacement. However, the transfer drum and the fixing unit are not expected to have the same lifetime, and the transfer drum and the fixing unit are fixed. Even when either one of the means fails, both are replaced, so that there is a problem that normal parts are wasted and cost is increased.

  Further, in the apparatus described in Patent Document 3, if a sheet exists between the transfer unit and the fixing unit when an abnormality occurs in the apparatus, the sheet is removed from the image forming apparatus, and the sheet is removed from the transfer unit. It will be pulled out while being pinched at the nip. At this time, the paper is pulled out in contact with the image carrier that forms the nip with the transfer roller, and the image carrier may be damaged. Further, there is a problem that the paper on the paper transport guide is difficult to grip and workability is poor. Further, since the fixing unit is completely removed from the apparatus main body, a space is required for temporarily removing the removed fixing unit, and the removed fixing unit may be hit and damaged.

  The present invention provides an image forming apparatus that solves the above-described problems in a conventional image forming apparatus, can prevent damage to parts during jam processing, and can improve jam handling workability with an inexpensive configuration. Let it be an issue.

  According to the present invention, there is provided an image having an image carrier, a transfer unit that transfers an image carried by the image carrier onto a recording material, and a fixing unit that fixes the image transferred to the recording material. In the forming apparatus, the transfer unit and the fixing unit are integrally formed as a transfer fixing unit by holding the transfer unit and the fixing unit, and the transfer fixing unit is provided so as to be movable outward with respect to the apparatus main body. In conjunction with the movement of the unit to the outside of the apparatus main body, a transfer nip formed by pressure contact between the image carrier and the transfer means is separated, and in association with the movement of the transfer fixing unit to the inside of the apparatus main body, This can be solved by forming the transfer nip by bringing the image carrier and the transfer means into pressure contact with each other.

  In addition, an exterior unit that constitutes a part of the exterior surface of the image forming apparatus is attached to an end of the transfer fixing unit so as to be movable integrally with the transfer fixing unit, and the exterior unit includes the transfer fixing unit. It is preferable that the fixing unit is covered in the pull-out direction.

  In addition, the image forming apparatus includes exterior means capable of opening and closing a part of the exterior surface of the image forming apparatus, the exterior means and the transfer fixing unit are connected to each other, and the transfer fixing unit is disposed outside the apparatus main body by opening the exterior means. It is preferable that the transfer nip is separated and the transfer fixing unit is moved to the inside of the apparatus main body and the transfer nip is formed by closing the exterior unit.

In addition, it is preferable that a support unit is provided for supporting the transfer fixing unit on the apparatus main body when the transfer fixing unit is pulled out from the apparatus main body.
Further, it is preferable that a part of the holding member is a sheet conveyance guide member between the transfer unit and the fixing unit.

In addition, it is preferable that the transfer unit and the fixing unit are individually detachable from the transfer fixing unit.
In addition, it is preferable that an auxiliary member for supporting the apparatus main body when the transfer fixing unit is pulled out from the apparatus main body is provided on the side surface of the apparatus in the direction of pulling out the transfer fixing unit.

In addition, it is preferable that the auxiliary member is provided so as to be retractable in the apparatus main body.
Further, it is preferable that a guide member extending in the unit moving direction is provided on both sides of the transfer fixing unit in a direction orthogonal to the unit moving direction, and a receiving member for receiving the guide member is provided on the apparatus main body side. .

Further, it is preferable that a sheet feeding unit that feeds the recording sheet toward the transfer nip is provided, and a sheet conveyance path from the sheet feeding unit to the fixing unit is formed in a substantially straight line shape.
Further, a sheet stopper that can move between a nipping position for nipping the sheet and a non-nipping position for nipping the sheet is provided on the upstream side of the transfer nip, and the sheet stopper is moved to the nipping position when an abnormality occurs in the apparatus. Is preferred.

  Further, it is preferable that the sheet is sandwiched between the sheet stopper and the transfer fixing unit, and the sheet stopper is provided so as to be movable integrally with the transfer fixing unit.

  A paper feeding unit that feeds the recording paper toward the transfer nip, and the paper clamping force of the paper stopper is larger than the paper clamping force of the paper feeding unit; It is preferable to be provided so as to be releasable.

  According to the image forming apparatus of the present invention, the transfer nip is separated in conjunction with the movement of the transfer fixing unit to the outside of the apparatus main body, and the transfer nip is interlocked with the movement of the transfer fixing unit to the inside of the apparatus main body. Therefore, jam processing can be performed without applying a load different from that during normal operation to the transfer means and the image carrier. That is, it is possible to prevent the image carrier or the transfer unit from being damaged due to the unit drawer during the jam processing, which is a problem in the prior art, and simpler than the configuration in which the transfer unit and the fixing unit are separately attached and detached. Since it can be configured, cost increase can be suppressed.

  With the configuration of the second aspect, the transfer and fixing unit can be moved by opening and closing the exterior means, and the jam processing procedure can be reduced. In addition, it is possible to prevent the danger of inadvertently touching the fixing means that is a high temperature part.

  According to the configuration of the third aspect, the transfer nip is separated in conjunction with the movement of the transfer fixing unit to the outside of the apparatus main body by opening the exterior means, and in conjunction with the movement of the transfer fixing unit to the inside of the apparatus main body by closing the exterior means. Thus, a transfer nip can be formed. Therefore, it is possible to perform jam processing without applying a load different from that during normal operation to the transfer means and the image carrier.

  According to the fourth aspect of the present invention, it is possible to perform jam processing without removing the transfer and fixing unit from the apparatus main body. Further, it is possible to prevent the transfer unit and the fixing unit from being damaged. The risk of touching the fixing means in the high temperature part can be reduced.

  According to the fifth aspect of the present invention, a separate sheet conveyance guide member between the transfer unit and the fixing unit is not required, and the holding member can also serve as the guide member. Therefore, the device configuration can be simplified and the cost can be reduced.

According to the configuration of the sixth aspect, it is possible to individually repair or replace parts whose names and lifetime have been reached, and it is possible to save resources and reduce costs.
With the configuration of the seventh aspect, it is possible to prevent the apparatus main body from being inclined when the transfer fixing unit is pulled out from the apparatus main body.

With the configuration of the eighth aspect, the auxiliary member does not get in the way when the apparatus is used (when the apparatus is operating).
According to the configuration of the ninth aspect, it is not necessary to separately provide a slide rail, and an increase in cost can be suppressed.

  According to the configuration of the tenth aspect, the shape of the paper conveyance guide is not complicated, and the cost can be reduced. Further, the arrangement of the parts forming the conveyance path is simple, which can contribute to the downsizing of the apparatus.

  According to the configuration of the eleventh aspect, since there is a paper stopper on the upstream side of the transfer unit, the paper that has not reached the fixing means falls in the apparatus main body by moving the stopper to the paper clamping position when the abnormality of the apparatus occurs. Can be prevented.

  According to the configuration of the twelfth aspect, since the paper is sandwiched between the paper stopper and the transfer fixing unit and the paper stopper can move integrally with the transfer fixing unit, the paper can be removed simultaneously by pulling out the transfer fixing unit. Become. Therefore, the jammed paper can be easily removed.

  According to the configuration of the thirteenth aspect, even when the trailing edge of the sheet is sandwiched between the sheet feeding means when the apparatus is stopped due to the occurrence of a jam, the sheet can be removed simultaneously by the movement of the transfer fixing unit.

1 is a cross-sectional configuration diagram schematically illustrating an example of an image forming apparatus according to the present invention. 2 is a perspective view showing a transfer fixing unit of the image forming apparatus. FIG. FIG. 3 is a diagram illustrating a state where a transfer fixing unit is moved outward from the apparatus main body. It is a figure which shows a mode that the transfer fixing unit is supported by the slide rail. It is a schematic diagram explaining the problem at the time of transfer roller separation. It is a figure which shows the structural example and operation | movement which make a transfer nip contact / separate. It is a figure which shows another structural example which makes a transfer nip contact / separate. It is a figure which shows a mode that the transfer roller was spaced apart from the photoreceptor by opening an exterior cover. It is a perspective view which shows an example of the auxiliary member which supports an apparatus main body. It is a perspective view which shows another example of the auxiliary member which supports an apparatus main body. It is a perspective view which shows an example of the structure which supports a transfer fixing unit. FIG. 3 is a diagram illustrating an example of a configuration for supporting a transfer fixing unit as viewed from the rear side of the apparatus. FIG. 4 is a schematic diagram illustrating a state where a sheet that has passed through a sheet feeding unit reaches a transfer unit and does not reach a fixing unit. It is a figure which shows a mode that the paper fell in the apparatus main body. FIG. 6 is a diagram illustrating a state in which a sheet is prevented from dropping by a sheet stopper provided on the upstream side of a transfer unit. It is a figure which shows another structural example of a paper stopper. FIG. 6 is a diagram illustrating a state in which a sheet is sandwiched between a sheet stopper and a transfer fixing unit, and the sheet is removed together with the unit. It is a figure which shows the paper supply means provided so that raising / lowering was possible. 2 shows a second embodiment in which the invention is applied to a color image forming apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional configuration diagram schematically illustrating an example of an image forming apparatus according to the present invention. The image forming unit 1 is disposed at a substantially central portion of the apparatus main body. The image forming unit 1 includes a photosensitive drum 2 as an image carrier (paper image surface side rotating body), and a transfer roller 5 (paper non-image surface side rotating body) is provided below the photosensitive drum 2. Is provided. An electrostatic latent image is formed on the photosensitive drum 1 by an exposure unit (not shown), and toner is applied to the latent image from a developing device (not shown) to form a toner image on the photosensitive drum 1. On the other hand, the paper P is fed from the paper feed tray 8 by the paper feed means 3, and the photosensitive drum 1 and the transfer roller 5 are conveyed toward a transfer portion facing each other. The toner image on the photosensitive drum 1 is transferred onto a sheet at the transfer nip, and the toner image is fixed by heating and pressing by the fixing unit 6 and then discharged to the outside. As described above, in the image forming apparatus of the present embodiment, the paper P reaches the fixing unit 6 by passing under the image forming unit 1. In the present embodiment, a sheet conveyance guide (not shown) is provided between the sheet feeding unit 3 and the transfer unit 4. Further, as shown in the figure, a sheet conveyance guide 7 is provided between the transfer unit 4 and the fixing unit. In FIG. 1, the sheet conveyance guide 7 is illustrated as a thin plate, but as will be described later with reference to FIG. 2, the sheet conveyance guide 7 is a holding member that holds the transfer unit 4 and the fixing unit 6. The upper surface of the member between the transfer unit 4 and the fixing unit 6 serves as a conveyance guide plate (guide unit).

  As shown in FIG. 2, in this embodiment, the transfer unit 4, the fixing unit 6, and the sheet conveyance guide 7 are integrally transferred by holding the transfer unit 4 and the fixing unit 6 with the sheet conveyance guide 7. The fixing unit 9 is configured. The transfer unit 4 is held on the sheet conveyance guide 7 by fitting a protruding portion 4 a protruding from the side surface of the transfer unit 4 to a positioning unit 7 a provided on the sheet conveyance guide 7, for example. Further, the fixing unit 6 is held on the sheet conveyance guide 7 by, for example, fitting a protruding portion 6 a protruding from the side surface of the fixing unit 6 into a positioning portion 7 b that is a notch provided in the sheet conveyance guide 7. . The protrusions 4a and the protrusions 6a of the transfer unit 4 and the fixing unit 6 are provided on the left and right sides in the apparatus width direction (only the right side is shown in the drawing). The transfer unit 4 and the fixing unit 6 can be individually attached to and detached from the paper transport guide 7 (with respect to the transfer fixing unit 9).

  When a jam occurs with the leading edge of the paper reaching between the transfer means 4 and the fixing means 6 (or when the apparatus is stopped due to an abnormality), as shown in FIG. So as to retract to the outside (back side in this embodiment). At this time, the transfer fixing unit 9 pulled out from the apparatus main body is supported by the apparatus main body by a lock mechanism (support means) (not shown). Thereby, it is possible to perform the jam processing without removing the transfer fixing unit 9 from the apparatus main body. At this time, since the paper P sandwiched between the nip portion of the transfer roller 5 and the photosensitive member 2 is separated from the photosensitive member 2 forming the nip with the transfer roller 5, the photosensitive member 2 is damaged when the paper P is removed from the apparatus. Can be prevented. Further, the sheet P is hung from the upstream side (upstream side in the sheet conveying direction) of the photosensitive member 2 and is easily gripped. Furthermore, since the transfer unit 4, the fixing unit 6, and the sheet conveyance guide 7 are integrally formed by holding the transfer unit 4 and the fixing unit 6 with the sheet conveyance guide 7, the transfer unit 4 and the fixing unit 6 are configured as one unit. New holding parts for installation are not required, and cost increase can be reduced. In the illustrated example, the jam processing is performed by opening a door (not shown) provided on the right side of the apparatus.

  FIG. 4 shows a specific embodiment of the holding means of the transfer fixing unit 9. As shown in this figure, the transfer and fixing unit 9 is held on the apparatus main body by a slide rail 10 and is movable outward from the apparatus main body. The transfer fixing unit 9 pulled out from the apparatus main body is supported on the apparatus main body by a slide rail 10. In this embodiment, an exterior cover 11 (exterior means) is attached to the outside of the transfer fixing unit 9 (outside of the apparatus main body), and the exterior cover 11 moves integrally with the transfer fixing unit 9. ing. The exterior cover 11 has a size that covers the transfer and fixing unit 9 in the pull-out direction, and of course covers the fixing unit 6. For this reason, when the transfer fixing unit 9 is pulled out, the fixing unit 6 in the high temperature part is covered with the exterior cover 11, and it is possible to prevent the risk of inadvertently touching the fixing unit 6. When the transfer fixing unit 9 is housed in the apparatus, the exterior cover 11 closes the apparatus opening (opening for retracting the transfer fixing unit 9).

  When a jam occurs with the leading edge of the paper reaching between the transfer unit 4 and the fixing unit 6, the outer cover 11 is opened so that the transfer fixing unit 9 and the outer cover 11 are integrated with the apparatus main body. Therefore, the user can remove the jammed paper in the apparatus simply by opening the outer cover 11. Further, after removing the jammed paper, it is only necessary to close the outer cover 11, and the work procedure of the jam processing can be reduced. Further, jamming can be performed without touching the fixing unit 6.

  By the way, as indicated by the phantom line in FIG. 5, the transfer roller 5 is applied with a force that presses against the photosensitive drum 2, so that when the transfer fixing unit 9 is pulled out from the apparatus main body, The transfer roller 5 and the photosensitive drum 2 are not immediately separated.

  Therefore, in this embodiment, a configuration is provided in which the transfer nip is brought into contact with and separated from the transfer fixing unit 9 in conjunction with the insertion and removal. That is, as shown in FIG. 6, a convex portion 7c is provided on the upper portion of the paper conveyance guide 7 (a position outside the paper conveyance region), and the biasing guide is provided downstream of the convex portion 7c in the pull-out direction of the transfer fixing unit 9. Part 12 is provided. The urging guide portion 12 has a convex shape facing downward, and its apex portion is formed in a curved shape. The urging guide portion 12 may be provided as a part of the main body frame, or may be provided as a component for urging separately.

  As shown in FIG. 6A, when the transfer fixing unit 9 is set at the operating position in the apparatus main body, the position of the convex portion 7 c of the paper transport guide 7 is in contact with the inside of the urging guide portion 12. However, at this time, urging by the urging guide portion 12 is not performed. Then, as shown in FIG. 6B, the convex portion 7c of the paper transport guide 7 comes into contact with the urging guide portion 12 by the movement in the direction of arrow A when the transfer fixing unit 9 is pulled out from the apparatus main body, and the arrow B Biased in the direction. As a result, the sheet conveyance guide 7 moves downward, and the transfer roller 5 is separated from the photosensitive drum 2 (the transfer nip is released). (B) When the paper transport guide 7 is further pulled out from the position shown in the drawing, the paper transport guide 7 returns to its original height (if the operating position is at the height at which the transfer roller 5 is pressed against the photosensitive drum 2). (In this example, the paper conveyance guide 7 is urged upward by an urging means (not shown) so that the transfer roller 5 is pressed against the photosensitive drum 2).

  In this example, as described above, when the transfer and fixing unit 9 is set at the operating position, the convex portion 7c is in contact with the inner side of the biasing guide portion 12 (in a non-biased state). Since the biasing guide portion 12 immediately biases by the operation of pulling out the transport guide 7, the transfer roller 5 and the photosensitive drum 2 are immediately separated when the paper transport guide 7 is pulled out. Therefore, it is possible to prevent the transfer roller 5 and the photosensitive drum 2 from being rubbed, and to effectively prevent the transfer roller 5 and the photosensitive drum 2 from being damaged or damaged.

  When the drawn transfer fixing unit 9 is inserted into the apparatus main body, the sheet conveying guide 7 is moved downward by the projection 7c coming into contact with the biasing guide portion 12, and the projection 7c is biased by the biasing guide portion. After passing through the apex of 12, the sheet conveyance guide 7 rises and returns to its original height. Therefore, when the transfer fixing unit 9 returns to the operating position, the transfer roller 5 rises from below and is pressed against the photosensitive drum 2, so that the transfer roller 5 and the photosensitive roller 5 are also exposed when the paper transport guide 7 is inserted (set). By rubbing the body drum 2, it is possible to effectively prevent the transfer roller 5 and the photosensitive drum 2 from being damaged or scratched.

  As described above, in the image forming apparatus according to the present invention, the nip between the transfer roller 5 and the photosensitive drum 2 is separated in conjunction with the movement of the transfer fixing unit 9 to the outside of the apparatus main body. Since the transfer roller 5 of the transfer means 4 is moved in the direction of pressing the photosensitive member 2 in conjunction with the insertion of the apparatus 9 to the position for normal use with respect to the apparatus main body, a load different from that during normal operation is applied to the transfer roller. 5 or the photosensitive member 2 can be jammed. That is, it is possible to prevent the image carrier or the transfer unit from being damaged due to the unit drawer during the jam processing, which is a problem in the prior art, and simpler than the configuration in which the transfer unit and the fixing unit are separately attached and detached. Since it can be configured, cost increase can be suppressed.

7 and 8 show another example of a configuration in which the transfer nip is brought into contact with and separated from the transfer fixing unit 9 in conjunction with the insertion and removal.
As shown in FIG. 7, the outer cover 11 is pivotally supported on the frame of the apparatus main body by a shaft 13 at the lower end thereof, and can be opened with the shaft 13 as a fulcrum as shown in FIG. The exterior cover 11 is provided with a convex portion 11a protruding above the shaft 13 and inside the apparatus. On the other hand, a guide portion 14 is attached to the lower end portion of the sheet conveyance guide 7 of the transfer fixing unit 9, and the end portion of the guide portion 14 and the convex portion 11 a of the exterior cover are connected by a shaft 15. The shaft 13, the convex portion 11a, and the guide portion 14 are provided on both sides in the left-right width direction (see FIG. 2) of the apparatus, and the transfer fixing unit 9 and the exterior cover 11 are connected on both sides in the width direction. .

  Then, when the exterior cover 11 is opened as shown in FIG. 8, the position of the shaft 15 moves to the outside of the apparatus rather than when the cover is closed, and is lowered below that when the cover is closed. To move to. As a result, the position of the transfer fixing unit 9 on which the guide portion 14 is mounted also moves to the outside of the apparatus and falls downward, the transfer roller 5 is separated from the photosensitive drum 2, and the transfer nip is released. When the opened exterior cover 11 is closed as shown in FIG. 7, the position of the shaft 15 is raised, the transfer fixing unit 9 is also raised, and the transfer roller 5 is pressed against the photosensitive drum 2 to form a transfer nip. The

  As described above, in this configuration example, the nip between the transfer roller 5 and the photosensitive drum 2 is separated in conjunction with the movement of the transfer fixing unit 9 to the outside of the apparatus main body by opening the exterior cover 11, and the exterior cover 11 is closed. A nip between the transfer roller 5 and the photosensitive drum 2 is formed in conjunction with the movement of the transfer fixing unit 9 to the inside of the apparatus main body. Therefore, the jam processing can be performed without applying a load different from that during the normal operation to the transfer roller 5 and the photosensitive member 2.

Here, positioning of the transfer unit 4 and the fixing unit 6 to the transfer fixing unit 9 will be described with reference to FIG.
As shown in FIG. 2, the transfer unit 4 and the fixing unit 6 both have protrusions 4 a and 6 a provided on both sides in the left-right direction, and a positioning unit 7 a provided by cutting out a part of the sheet conveyance guide 7 from above. The position is determined by insertion. At this time, a pressing member (not shown) for pressing the transfer fixing unit 9 from above may be provided. The transfer means 4 and the fixing means 6 have their protrusions 4 a and 6 a fitted into the positioning portion 7 a of the paper transport guide 7, so that the position in the front-rear direction is determined. The vertical position is determined by being supported. With respect to the left-right direction, a configuration in which a groove (not shown) provided in the protruding portion is fitted in the paper transport guide, or a configuration in which the position is determined using an E ring, a stop ring, or the like can be considered. By installing the transfer means 4 and the fixing means 6 in the paper conveyance guide 7 in this way, the transfer means 4 and the fixing means 6 can be individually separated in the upward direction after the transfer fixing unit 9 is pulled out from the apparatus main body. Only the unit that has failed or has reached the end of its life can be replaced, and the normal unit can be prevented from being wasted. Moreover, since it can be separated individually, it is easy to carry out partial repairs, and the carrying load can be reduced.

  By the way, when the transfer fixing unit 9 is pulled out from the apparatus main body, the entire image forming apparatus may be inclined in the direction in which the transfer fixing unit 9 is pulled out due to the weight of the transfer fixing unit 9. Therefore, it is preferable to provide an auxiliary member for preventing the inclination of the image forming apparatus (supporting the apparatus main body).

  FIG. 9 is a perspective view illustrating an example of an auxiliary member that supports the apparatus main body. In this figure, auxiliary members 16 and 16 for supporting the image forming apparatus are provided at the lower ends on both sides of the side surface of the apparatus on the side from which the transfer fixing unit 9 is pulled out from the image forming apparatus main body 20 (in this example, the back surface of the apparatus). . The auxiliary members 16, 16 have a right triangle shape, and the base of the triangle comes into contact with a table, a desk or the like on which the image forming apparatus is placed, and prevents the image forming apparatus body 20 from tilting.

  FIG. 10 is a perspective view showing another example of an auxiliary member that supports the apparatus main body. In this figure, auxiliary members 17 and 17 for supporting the image forming apparatus are provided at both lower ends of both sides of the apparatus side (in this example, the back of the apparatus) on the side where the transfer and fixing unit 9 is pulled out from the image forming apparatus main body 20. . The auxiliary members 17, 17 are provided with a side surface in an arc shape or a curved shape, and can be drawn out from the inside of the apparatus main body 20 and stored in the main body. When the transfer and fixing unit 9 is moved from the apparatus main body 20 to the outside, the auxiliary members 17 and 17 are pulled out to prevent the image forming apparatus from being inclined as shown in the figure. After the transfer and fixing unit 9 is inserted into the apparatus main body, the auxiliary members 17 and 17 are stored in the storage spaces 18 and 18 in the main body, so that the auxiliary members 17 and 17 do not get in the way when the apparatus is operated.

  FIGS. 11 and 12 are a perspective view and a rear view (view from the back of the apparatus) showing an example of a configuration for supporting the transfer fixing unit 9. Although FIG. 4 shows an example in which a slide rail is used as an example of a configuration for supporting the transfer fixing unit 9, using a commercially available product or another part dedicated to the slide rail causes an increase in cost. Therefore, as shown in FIGS. 11 and 12, on the both sides in the width direction of the transfer fixing unit 9 (on both sides in the direction orthogonal to the moving direction of the transfer fixing unit 9) as viewed from the pulling direction of the transfer fixing unit 9 (the rear side of the apparatus). The slide guides 21 and 21 (guide members) extending in the unit moving direction are projected. On the other hand, receiving members 22 and 22 for receiving the slide guides 21 and 21 are provided on the apparatus main body 20 side.

  For example, if the material of the paper transport guide 7 is a resin material, the slide guide 21 is integrally formed so as to include the slide guide 21. If the paper transport guide 7 is a sheet metal material, the slide guide 21 is bent in a bent shape. It can be configured. Moreover, the receiving member 22 can suppress cost by comprising a part of the frames (in this example, the side plates on the left and right sides) 23 and 23 as the receiving member 22.

  By the way, as shown in FIG. 1, a sheet conveyance path (shown by a one-dot chain line in the figure) from the sheet feeding means 3 to the fixing means 6 is formed as a conveyance path extending in a substantially straight line shape (substantially horizontal in this example). As a result, the shape of the paper transport guide can be simplified and can be configured at low cost. Further, since the transport path is substantially horizontal, the arrangement of the parts forming the transport path is not complicated, and the apparatus can be miniaturized.

  FIG. 13 shows a state in which the paper P that has passed through the paper supply unit 3 reaches the transfer unit (indicated by a two-dot chain line in the drawing) and does not reach the fixing unit 6. When an abnormality occurs in the image forming apparatus and the sheet P stops in the apparatus in the state shown in FIG. 13, the sheet P is held only in the transfer portion. Therefore, the transfer fixing unit 9 is attached to the apparatus main body to remove the sheet. When the sheet P moves outward, there is no portion that pinches the paper P, and the paper P may drop in the apparatus main body as shown in FIG.

  Therefore, as shown in FIG. 15, it is preferable to provide a paper stopper 25 on the upstream side of the transfer portion. The paper stopper 25 is provided so as to be movable up and down as indicated by solid lines and virtual lines in the drawing, and is held at a raised position indicated by a solid line during normal operation. When an abnormality occurs in the apparatus main body, the paper stopper 25 is lowered to the position indicated by the phantom line. When the paper P is present here, the paper is sandwiched between the paper stopper 25 and the paper guide 24 on the upstream side of the transfer unit. FIG. 15 shows a state in which the transfer fixing unit 9 is moved to the outside and the sheet P is held by the lowered sheet stopper 25 (virtual line) and the sheet guide 24. Thereby, it is possible to prevent the sheet from dropping when the transfer fixing unit 9 is pulled out from the apparatus main body. Note that the holding force of the sheet by the sheet stopper 25 and the sheet guide 24 is set to a force that allows the user to pull out (remove) the sheet P, such as the weight of the sheet stopper 25, for example. is there.

  FIG. 16 shows another configuration example of the paper stopper. The sheet stopper 26 shown in this figure is supported by the transfer fixing unit 9 and is provided so as to be movable up and down as indicated by a solid line and a virtual line in the figure. During normal operation, it is held at the raised position indicated by the solid line. When an abnormality occurs in the main body of the apparatus, the paper stopper 26 is lowered to the position indicated by the phantom line. The paper P is clamped by the guide portion 27a of the paper transport guide 27 extended to the end. When the paper transport guide 27 is moved outward with respect to the apparatus main body as shown in FIG. 17 with the paper held by the paper stopper 26, the paper P can be removed at the same time.

  Note that the force of the paper stopper 26 for clamping the paper is larger than the force of the paper feeding means 3 for clamping the paper so that the paper P can be removed even when the rear end of the paper P is sandwiched between the transport means 3. Is set to Alternatively, as shown in FIG. 18, the sheet feeding unit 3 is provided so as to be able to move up and down, and when an abnormality occurs, control is performed so that the sheet nipping by the sheet feeding unit 3 is released (separated from the sheet P) as indicated by a broken line in the figure. May be. Thus, the paper P sandwiched by the paper stopper 26 can be removed simultaneously when the paper transport guide 27 is pulled out.

FIG. 19 shows a second embodiment in which the present invention is applied to a color image forming apparatus.
The color image forming apparatus shown in this figure is a color printer that can form a full color image by adopting a tandem method, and forms a tandem image formed of four image forming units 32Bk, 32M, 32C, and 32Y in the upper part of the apparatus main body. Part 31 is arranged. An intermediate transfer belt 42 is disposed below the tandem image forming unit 31. This intermediate transfer belt 42 is an image carrier (paper image side rotating body) that carries a toner image primarily transferred from the photosensitive member 33 of each color image forming unit, and is wound around a plurality of support rollers in the drawing. Driven counterclockwise.

  Each image forming unit 32 (Bk, M, C, Y) has the same configuration except for the color of the toner to be handled. As a representative, the black unit 32Bk is provided with a photosensitive drum 33 as indicated by a reference numeral. is doing. Around the photosensitive drum 33, a charging unit 34, a developing device 35, a cleaning unit 37, and the like are arranged. Further, a transfer roller as a primary transfer unit is disposed inside the intermediate transfer belt 42 so as to face the photosensitive drum 33. 36 is provided. Further, an optical writing device 38 is disposed above the photosensitive drum 33, and laser scanning is performed on the photosensitive drum 33 to perform optical scanning.

  A secondary transfer unit 44 is provided below the intermediate transfer belt 30. The secondary transfer unit 44 includes a transfer conveyance belt 33 (paper non-image-side rotating body), and a support roller on one side around which the transfer conveyance belt 33 is stretched is a secondary transfer roller 45. A secondary transfer roller 45 is pressed against the opposing roller 48 across the intermediate transfer belt 30 and the transfer conveyance belt 33 to form a secondary transfer nip.

  A fixing means 46 is arranged on the right side of the secondary transfer means 44 in the figure. The secondary transfer unit 44 and the fixing unit 46 are held by a holding member (not shown) and integrally configured as a transfer fixing unit 49. The transfer fixing unit 49 is provided so as to be movable outward (right side in FIG. 19) with respect to the image forming apparatus main body, like the transfer fixing unit 9 in the monochrome image forming apparatus of the first embodiment described above. .

  The lower part of the main body of the apparatus is provided as a paper feed unit 39, and is provided with a paper feed tray for stacking paper and a paper feed means for feeding the paper stacked in the paper feed tray. To send. The paper sent out from the paper supply unit 39 is sent to the registration roller 41 via the transport roller pair 40.

Since the image forming operation in the tandem type color printer configured as described above is well known, description thereof will be omitted.
When a jam occurs in a state where the sheet is nipped in the secondary transfer nip (the leading end of the sheet has reached between the secondary transfer roller 45 and the fixing unit 46), the transfer fixing unit 49 is connected to the image forming apparatus main body. Accordingly, the jam processing can be performed without removing the transfer fixing unit 49 from the apparatus main body.

  At this time, in the second embodiment, a configuration in which the secondary transfer nip is brought into contact with and separated from the transfer fixing unit 49 in conjunction with the insertion and removal is provided. That is, with the same configuration as described in FIGS. 6 to 8 in the first embodiment, the pressure contact of the secondary transfer nip is released in conjunction with the operation of moving the transfer fixing unit 49 to the outside with respect to the image forming apparatus main body. In addition, the secondary transfer nip is pressed in conjunction with the operation of returning the transfer fixing unit 49 to the operating position. As a result, jam processing can be performed without applying a load different from that during normal operation to the image carrier (paper image surface side rotating body) or secondary transfer means (paper non-image surface side rotating body). That is, it is possible to prevent the image carrier or the transfer means (secondary transfer means) from being damaged by the unit drawing during jam processing, which has been a problem in the prior art, and the transfer means (secondary transfer means) and the fixing means can be Compared to a configuration that can be attached and detached separately, a simple configuration can be achieved, so that an increase in cost can be suppressed.

  It is preferable that auxiliary members for preventing the image forming apparatus from tilting when the transfer fixing unit 49 is pulled out from the apparatus main body are provided in the same manner as the auxiliary members 16 and 17 described with reference to FIGS. Further, as a configuration for supporting the transfer fixing unit 49, it is possible to use a slide rail or the slide guide 21 and the receiving member 22 described with reference to FIGS. Furthermore, the paper stoppers 25 and 26 (FIGS. 15 to 17) may be provided as in the first embodiment. Further, in order to facilitate the removal of the jam, the registration rollers 41 may be provided so as to be separated from each other, and control may be performed so as to release the sheet nipping when an abnormality occurs.

  As mentioned above, although this invention was demonstrated by the example of illustration, this invention is not limited to this. For example, in the first embodiment, the holding member that holds the transfer unit 4 and the fixing unit 6 is configured as the sheet conveyance guide 7, but a guide member that guides conveyance of the sheet may be provided separately from the holding member. Further, the transfer unit 4 may be configured as a transfer conveyance belt like the secondary transfer unit 44 of the second embodiment. In the second embodiment, the secondary transfer unit 44 is a transfer conveyance belt type. However, like the transfer unit 4 of the first embodiment, a transfer roller type may be used. In this case, the holding member that holds the transfer roller and the fixing unit may be configured as a sheet conveyance guide as in the first embodiment.

  An appropriate configuration can be adopted as the configuration in which the transfer unit (secondary transfer unit) and the fixing unit are held by the holding member. The fixing means may be a belt fixing system. The image carrier (paper image surface side rotator) of the first embodiment is a drum-like rotator, but may be a belt-like image carrier. In the second embodiment, the image bearing member (paper image surface side rotating member) is an intermediate transfer belt. However, an apparatus configuration using a drum-shaped intermediate transfer member is also possible.

  The configuration of the image forming unit of the image forming apparatus is also arbitrary, and the arrangement order of the color image forming units in the tandem system is arbitrary. In addition to the tandem type, a configuration in which a plurality of developing devices are arranged around a single photosensitive member, or a configuration using a revolver type developing device is also possible. Further, the present invention can be applied to a full-color machine using three color toners and a multi-color machine using two color toners. Of course, the image forming apparatus is not limited to a printer, and may be a copier, a facsimile machine, or a multifunction machine having a plurality of functions.

DESCRIPTION OF SYMBOLS 1 Image formation part 2 Photosensitive drum (image carrier)
DESCRIPTION OF SYMBOLS 3 Paper feed means 4 Transfer means 5 Transfer roller 6 Fixing means 7 Paper conveyance guide 9 Transfer fixing unit 11 Exterior cover (exterior means)
13, 15 Axes 16, 17 Auxiliary member 21 Slide guide (guide member)
22 Receiving members 25, 26 Paper stopper 27 Paper transport guide 31 Tandem image forming section 42 Intermediate transfer belt (image carrier)
43 Transfer conveyor belt 44 Secondary transfer means 46 Fixing means 49 Transfer fixing unit

JP-A-5-197243 Japanese Patent Laid-Open No. 4-234057 JP 2004-53987 A

Claims (13)

In an image forming apparatus comprising: an image carrier; a transfer unit that transfers an image carried by the image carrier onto a recording material; and a fixing unit that fixes the image transferred to the recording material.
The transfer unit and the fixing unit are integrally held as a transfer fixing unit by holding the transfer unit and the fixing unit, and the transfer fixing unit is provided to be movable outward with respect to the apparatus main body.
In conjunction with the movement of the transfer and fixing unit to the outside of the apparatus main body, the transfer nip formed by the image carrier and the transfer means being pressed against each other is separated, and the transfer and fixing unit is linked to the movement of the transfer fixing unit to the inside of the apparatus main body The image forming apparatus is configured to form a transfer nip by bringing the image carrier and the transfer unit into pressure contact with each other.   An exterior unit constituting a part of the exterior surface of the image forming apparatus is attached to an end of the transfer fixing unit so as to be movable integrally with the transfer fixing unit. The image forming apparatus according to claim 1, wherein the fixing unit is covered. Having exterior means capable of opening and closing a part of the exterior surface of the image forming apparatus, the exterior means and the transfer fixing unit are connected,
The transfer fixing unit moves to the outside of the apparatus main body by opening the exterior means, and the transfer nip is separated,
The image forming apparatus according to claim 1, wherein the transfer fixing unit is moved to the inside of the apparatus main body and the transfer nip is formed by closing the exterior unit.   The image forming apparatus according to claim 1, further comprising a supporting unit that supports the transfer fixing unit to the apparatus main body when the transfer fixing unit is pulled out from the apparatus main body.   The image forming apparatus according to claim 1, wherein a part of the holding member is a sheet conveyance guide member between the transfer unit and the fixing unit.   The image forming apparatus according to claim 1, wherein the transfer unit and the fixing unit are individually detachable from the transfer fixing unit.   The image forming apparatus according to claim 1, wherein an auxiliary member for supporting the apparatus main body when the transfer fixing unit is pulled out from the apparatus main body is provided on a side surface of the apparatus in the transfer fixing unit pull-out direction.   The image forming apparatus according to claim 7, wherein the auxiliary member is storable in the apparatus main body.   A guide member extending in the unit moving direction protrudes on both sides in a direction orthogonal to the unit moving direction of the transfer fixing unit, and a receiving member for receiving the guide member is provided on the apparatus main body side. The image forming apparatus according to claim 1.   2. A sheet feeding unit for feeding a recording sheet toward the transfer nip, wherein a sheet conveyance path from the sheet feeding unit to the fixing unit is formed in a substantially straight line. The image forming apparatus described in 1.   A sheet stopper that can move between a nipping position for nipping the sheet and a non-nipping position for nipping the sheet is provided on the upstream side of the transfer nip, and the sheet stopper is moved to the nipping position when an abnormality occurs in the apparatus. The image forming apparatus according to any one of claims 1 to 10.   12. The image forming apparatus according to claim 11, wherein the sheet is sandwiched between the sheet stopper and the transfer fixing unit, and the sheet stopper is provided so as to be movable integrally with the transfer fixing unit. A sheet feeding unit that feeds the recording sheet toward the transfer nip, and the sheet clamping force of the sheet stopper is greater than the sheet clamping force of the sheet feeding unit, or the sheet clamping of the sheet feeding unit can be released The image forming apparatus according to claim 12, wherein the image forming apparatus is provided.

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