JP2005331877A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which exhibits a satisfactory maintenability and is equipped with an apparatus opening/closing mechanism for preventing damages to respective members when a user opens and closes a part of the apparatus and accesses a transfer device which includes a belt body. <P>SOLUTION: The image forming apparatus comprises an opening/closing member 11 which opens the inside of the apparatus and the transfer device 5. The transfer device 5 comprises a cover 26 which covers parts other than the part opposed to an image carrier 1 on the surface of the belt body 5b in the fixed state, and a shutter 27 which is automatically interlocked with the opening and closing of the opening/closing member 11 and a shutter pressing member 28 which energizes the shutter 27. When the opening/closing member 11 is closed by a pressing force of the shutter pressing member 28, the shutter 27 overlaps the cover 26 and the surface of the belt body 5b is allowed to contact with the part facing a plurality of image carriers 1 of the belt body 5b. When the opening/closing member 11 is opened, the shutter 27 is moved in the direction of covering the part facing the image carriers 1 of the belt body 5b upon the image formation. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a color image forming apparatus using a plurality of color developers using an electrostatic recording system or an electrophotographic system, such as a printer, a copying machine, and a facsimile machine.

  Conventionally, as a color image forming apparatus, each color has a developing device containing a yellow, magenta, and cyan developer, and in some cases, a black developer in addition to the above three colors, and a plurality of these developing devices. Some devices are arranged on a straight line or a curve to develop an electrostatic latent image corresponding to each color developer.

  There are a direct transfer method and an intermediate transfer method as processes for superimposing a plurality of color images in the color image forming apparatus until a final visible image is obtained on the transfer material.

  In the direct transfer method, since the developer is transferred from the image carrier to the transfer material, the transfer environment due to the physical properties of the transfer material, the transferability of the transfer material, and the like affect the image quality. On the other hand, in the intermediate transfer method, since the transfer target in the step of overlapping the developer is always the same object, that is, an intermediate transfer body, a stable superimposed image can be obtained.

  When a color image forming apparatus using an intermediate transfer member is operated, a developer that is a consumable item may be used up in a cycle shorter than the life of the apparatus main body. In that case, it is necessary to replenish the developer or replace the developing device including the developer.

  In addition, with respect to the intermediate transfer member, the formed image may become a defective image due to mishandling by the user, unexpected damage, deterioration due to long-term use, etc., in order to obtain a good image In addition, it is essential to repair or replace the intermediate transfer member.

  However, a developing device using an electrophotographic technique and an adjacent image carrier are generally used as an exposure device for forming an electrostatic latent image on the image carrier or an intermediate transfer member to which a developed image is transferred. Often placed in an enclosed state.

  In addition, a cleaning mechanism for removing the developer remaining on the intermediate transfer body without being transferred to the transfer material, and a plurality of components such as the removed developer container are often provided. Conventionally, a configuration has been adopted in which a plurality of doors are provided in the image forming apparatus for replacement of the developing device so that a user can access the inside of the apparatus main body. In order to access from the user, the movement of the user is necessary, and it has never been excellent in maintainability.

  As a configuration in which a plurality of doors are not provided, FIG. 10 shows a schematic diagram of a conventional color image forming apparatus having a configuration disclosed in Patent Document 1. In FIG. A plurality of image forming units composed of an exposure device 300 from above the image forming apparatus, a developing device 306 and an image carrier 301 arranged in the horizontal direction below the exposure device 300, an intermediate transfer unit 302 having an intermediate transfer member 302a below the image forming unit, The transfer material storage unit 303 is arranged below in this order. A fixing device 304 is disposed downstream of the transfer material.

  FIG. 11 shows a state in which the access door 305 provided at the upper part of the image forming apparatus shown in FIG. 10 is opened, and the exposure apparatus 300 is placed on the access door 305 side. The access door 305 is pivoted about one end to open and close. An image forming unit such as a developing device 306 and an image carrier 301 and an intermediate transfer unit 302 are provided on the fixed side of the apparatus with the upper part opened. When detaching the intermediate transfer unit 302, it is essential that the user once removes all of the plurality of image forming units such as the developing device 306 and the image carrier 301 from above. In order to omit such an operation, a separate door must be provided in order to take out the intermediate transfer unit 302 below, and it is inevitable that there will be multiple doors and multiple access directions.

Thus, in the conventional example, the user has to perform complicated operations. For this reason, the intermediate transfer member may be damaged when the user accesses the inside of the apparatus main body.
JP 9-2111926 A

  An object of the present invention is to provide a belt such as an intermediate transfer member or a transfer material carrier inside the apparatus main body by a user opening and closing a part of the apparatus, supplying a developer, replacing each member of the image forming means, and jamming. An object of the present invention is to provide an image forming apparatus provided with a device opening / closing mechanism that is excellent in maintainability and prevents damage to each member when accessing a transfer device including a body and a plurality of image forming units for each color.

The above object is achieved by the image forming apparatus according to the present invention. In summary, according to the present invention, a plurality of image forming portions in which a developer image is formed on the surface of each image carrier, and a surface facing the image carrier in the plurality of image forming portions move during image formation. A transfer device that transfers the developer image onto a transfer material, and an opening / closing member that opens the inside of the device, the opening / closing member detachably mounting the transfer device In an image forming apparatus that operates,
The transfer device includes a cover that covers a portion of the belt body surface other than the portion facing the image carrier in a fixed state, a shutter that automatically interlocks with opening and closing of the opening and closing member, and a shutter pressing that biases the shutter A member, and
Due to the pressing force of the shutter pressing member, the shutter is overlapped with the cover when the opening / closing member is closed, thereby the belt body at the opposing portion of the belt body and the plurality of image carriers. The image is characterized in that the surface can come into contact with the image carrier, and when the opening / closing member is opened, the belt body moves in a direction to cover a portion of the belt body facing the image carrier at the time of image formation. A forming apparatus is provided.

  According to an embodiment of the present invention, the transfer device is held by the pressing member on the opening / closing member.

  The image forming apparatus according to the present invention includes a plurality of image forming units on which developer images are formed on the surfaces of the respective image carriers, and a belt on which surfaces facing the image carriers in the plurality of image forming units move during image formation. An image forming apparatus comprising a transfer device for transferring a developer image onto a transfer material and an opening / closing member for opening the inside of the device, wherein the opening / closing member detachably mounts the transfer device to perform an opening / closing operation. In the apparatus, the transfer device includes a cover that covers a portion other than the portion of the belt surface facing the image carrier in a fixed state, a shutter that automatically interlocks with opening and closing of the opening and closing member, and a shutter pressing member that biases the shutter. When the opening / closing member is closed, the shutter is overlapped with the cover by the pressing force of the shutter pressing member, so that the bell is located at the opposing portion of the belt body and the plurality of image carriers. When the body surface can come into contact with the image carrier and the opening / closing member is opened, the belt body moves in a direction to cover the portion of the belt body facing the image carrier during image formation. Since the transfer device can be easily detached and attached from the access door provided in units, including the belt body, and the shutter covers and protects the belt body, the user can damage the belt body during access. It can be prevented and the usability is improved.

  Also, the openable member is opened by holding a replaceable transfer device having a cover and shutter for protecting and covering the intermediate transfer member on the openable member, and holding the openable member in a floating state via the pressing member. Since the transfer device is attached to the opening / closing member side, the transfer device, the image forming unit, and the transfer material conveyance path are highly visible to the user, and the image forming unit and the transfer device are easily accessible. It becomes possible.

  Furthermore, the user can position the transfer device relative to the image forming unit and the transfer material transport unit by simply closing the opening / closing member, and the shutter is also opened at the same time. Good quality images can be obtained over a long period of time through maintenance.

  The image forming apparatus according to the present invention will be described below in more detail with reference to the drawings.

Example 1
FIG. 1 is a schematic cross-sectional view of an image forming apparatus A according to the present embodiment and a color image forming apparatus using an electrophotographic system. The image forming apparatus A shown here is a laser beam printer that can form a four-color full-color image.

  This image forming apparatus A forms an image through a process of fixing an image visualized with a developer (toner) onto a transfer material by heat or the like in a plurality of image forming units configured for each color to be formed. A tandem type image forming apparatus that performs image transfer, and an intermediate transfer type image forming apparatus that collectively transfers a color developer image (toner image) to a transfer material from a plurality of image forming units S via an intermediate transfer unit 5. is there.

  Each image forming unit S includes a photosensitive drum 1 (1Y, 1M, 1C, 1BK), which is a drum-type electrophotographic photosensitive member, as a first image carrier. The photosensitive drum 1 is rotationally driven, for example, counterclockwise by driving means (not shown).

  In each image forming unit S, a charging device 2 (2Y, 2M, 2C, 2BK) for uniformly charging the surface of the photosensitive drum 1, and toner is attached to the electrostatic latent image on the photosensitive drum 1 for development. Development device 4 (4Y, 4M, 4C, 4BK) is provided, and each image forming unit S flashes a light source (for example, laser light or LED light) in the vicinity thereof based on image information. An exposure device 3 (3Y, 3M, 3C, 3BK) for forming an electrostatic latent image on the photosensitive drum 1 is provided. Opposing each of the image forming portions S, an intermediate transfer unit 5 constituting a transfer device including an intermediate transfer member 5b as a second image carrier to which a toner image on the photosensitive drum 1 is transferred is installed. Yes. In this case, the intermediate transfer member 5b is an endless belt and rotates clockwise.

  In each image forming unit S, the photosensitive drum 1 is integrated with the developing device 4, and is fixedly arranged in parallel to the intermediate transfer unit 5. The developing device 4 that develops the electrostatic latent image on the photosensitive drum 1 has four developer accommodating portions 4b that accommodate four color toners. Each developer accommodating portion 4 b is provided with a developer carrying roller 4 a that bears toner as a developer on the surface and that faces the photosensitive drum 1 when the developer accommodating portion 4 b faces the photosensitive drum 1. The electrostatic latent image on the photosensitive drum 1 can be developed by the developer carrying roller 4a.

  One full-color toner electrostatically adsorbed on the intermediate transfer member 5b by sequentially transferring and superimposing each color on the surface of the intermediate transfer member 5b facing the developer image (toner image) developed on the photosensitive drum 1. An image is formed. Incidentally, in order to transfer the toner from the photosensitive drum 1 to the intermediate transfer belt 5b, transfer means 5d (5dY, 5dM, 5dC, 5dBK) for generating an electric bias with respect to the photosensitive drum 1 is provided with the belt 5b interposed therebetween. 1 on the opposite side.

  After forming a toner image in which each color is superimposed on the intermediate transfer member 5b, the intermediate transfer member 5b further rotates to the transfer portion E where the toner image is transferred onto the transfer material. The transfer material in the transfer material storage box 6 is supplied to the transfer unit E by the paper feeding / conveying device 7 at a predetermined timing. In the transfer portion E, transfer means 5e for generating an electric bias with respect to the transfer belt 5b is provided on the opposite side of the transfer belt 5b with the transfer material interposed therebetween.

  In this way, the toner image is collectively transferred onto the transfer material using the electrostatic attraction force. That is, the intermediate transfer unit 5 constitutes a transfer device that transfers the toner image to the transfer material together with the transfer means 5e. The transfer unit 5 e is a separate body from the intermediate transfer unit 5.

  Furthermore, the transfer material is conveyed to the fixing device 8 in order to fix the toner image on the transfer material. In the fixing device 8, the toner on the transfer material is melted and fixed using heat, pressure, or the like.

  The transfer material that has passed through the fixing device 8 is discharged to the paper discharge tray 10 by the transport unit 9.

  The alternate long and short dash line indicates the transfer material conveyance path 20.

  Here, in the transfer material transport path 20, a transfer material jam has occurred among the transfer material storage unit 6, the image transfer unit E from the intermediate transfer body 5 to the transfer material, and the fixing device 8. To do.

  In this case, by opening one access door 11 described later, the visibility of the user is ensured from the lower side of the image forming unit S to the entire conveying path to the fixing device 8 as indicated by the arrow Z. . Therefore, the user can easily perform jam processing.

  In the conventional image forming apparatus, when performing maintenance such as jam processing by accessing from one opening / closing member (access door) 11, the user needs a complicated operation as described in the conventional example. According to the present invention, the color image forming apparatus can be maintained by a simple operation by the user. The structure of the access door 11 according to the present embodiment and the method for accessing the internal members will be described with reference to FIGS.

  In the image forming apparatus A of this embodiment, as is apparent from FIG. 1 used in the above description, the image forming portions S are arranged in the vertical direction. The primary transfer portions, which are the facing portions of the respective photosensitive drums 1 and the transfer means 5d, are arranged vertically so as to be aligned in the vertical direction. The intermediate transfer unit 5 is disposed on the access door 11 side. A transfer material conveyance path 20 from the transfer unit E to the fixing device 8 is disposed below the intermediate transfer unit 5 and each image forming unit S in the horizontal direction.

  As shown in FIG. 2, in this embodiment, the access door 11 is opened by rotating around a fulcrum 12 below the main body of the image forming apparatus A as a rotation center of the door 11, and installed in the vertical direction in the closed state. However, in the present embodiment, the outermost surface of the access door 11 is tilted so that the outermost surface of the access door 11 exists on the extension of the transfer material conveyance path 20.

  The intermediate transfer unit 5 including the intermediate transfer member 5b is mounted on the door 11 and rotates integrally therewith. The relationship between the internal structure of the access door 11 and the image forming apparatus is that the boundary between the image carrier 1 and the intermediate transfer unit 5, that is, the primary transfer section in which the primary transfer sections from the photosensitive drum 1 to the intermediate transfer body 5b of each image forming section S are arranged. Divided by plane T. Here, in the position of the primary transfer surface T, when the door 11 is in a closed state, that is, in the state where the door 11 is erected in the vertical direction, the uppermost end portion of the primary transfer surface T is the end portion 5g, and the lowermost end portion is the end portion. 5h. In the fully open state shown in FIG. 2, the end 5g is an end far from the apparatus main body, and the end 5h is an end close to the apparatus main body.

  Each image forming unit S is also exposed when the access door 11 is opened, and each image forming unit S is detachable. Thus, maintenance such as replenishment of developer and replacement of each member can be performed efficiently.

  Here, as a feature of the present invention, the intermediate transfer unit 5 is held in a floating state by pressing members 14 and 15 installed in a portion facing the intermediate transfer unit 5 inside the access door 11.

  FIG. 3 shows an enlarged view of the access door 11 and the intermediate transfer unit 5. FIG. 3A is a view of the access door 11 viewed from the primary transfer surface T side of the belt 5b, and is a view of the access door 11 viewed from above in the fully opened state. FIG. 3B is a cross-sectional view of the access door 11, and is a cross section cut in the XX direction shown in FIG. 3A along the moving direction of the belt surface of the intermediate transfer member 5b during image formation. FIG. 4 is a longitudinal sectional view cut in the YY direction shown in FIG. 3A in a direction crossing the traveling direction of the intermediate transfer belt 5b.

  As shown in FIG. 3B, the pressing members 14 and 15 are urging members such as springs arranged between the intermediate transfer unit 5 and the access door 11. In this embodiment, the pressing members 14 and 15 A pressing member 15 is provided near the pivot fulcrum 12, and the same material as the member 15 is disposed near the upper end (hereinafter referred to as “door end”) in the closed state of the door 11 on the side opposite to the pivot fulcrum 12. A member 14 is provided. However, other numbers and types of pressing members may be used.

  In the state where the door 11 is fully opened, as shown in FIG. 3A, the primary transfer surface T of the intermediate transfer belt 5b is shown by a diagonal pattern in the upper left direction in FIGS. 3A and 3B. The shutter 27 is fixed to the intermediate transfer unit 5 so as to be covered from the outside, and is covered with a cover 26 shown in an upper right diagonal line pattern in FIGS. .

  The intermediate transfer unit 5 is covered with a cover 26 on the primary transfer surface T except for a portion facing each image forming portion S, that is, a portion facing the transfer unit 5d, that is, between both ends and each image forming portion S. . In detail, as shown in FIG. 8, which will be described later, when the door 11 is closed, the shutter 27 slides and moves to a position where it overlaps the cover 26, so that only the primary transfer portion is opened. The primary transfer surface T provided with the transfer means 5d is in contact with the photosensitive drum 1 of each image forming section S. The cover 26 is provided on a fixing member 16 provided near the end 5g of the primary transfer surface T and a holding unit 38 (shown in the same pattern as the shutter 27 in the drawing) provided near the end 5h. Provided at both ends of the primary transfer surface T, and the width of the intermediate transfer member 5b between the other primary transfer portions, which is the width portion of the intermediate transfer member 5b, is crossed in the direction intersecting the moving direction from above. It is installed to cover.

  When the door 11 is fully opened, the primary transfer portion, which is an open portion of the cover 26, is covered with the shutter 27, and the primary transfer surface T is covered with the cover 26 and the shutter 27 alternately arranged. The shutters 27 that cover the primary transfer portions in the fully opened state of the door 11 are connected to each other at the width portion of the primary transfer surface T so that the intervals are always fixed so as to cover the primary transfer portions. It has become.

  As shown in FIG. 4, the shutter 27 and the cover 26 are plate members whose both ends are bent perpendicularly in cross section, and the intermediate transfer member 5b is interposed between the bent portions 26x and 27x of the ends. It is possible for the shutter 27 to overlap the inside of the cover 26 so that the bent portions 26x and 27x are directed in the same direction so that the width portions of the cover 26 are fitted. The cover 26 has a groove 26y on the inner side of the bent portion 26x of the end portion, and a convex portion 27y provided on the outer side of the bent end portion 27x of the shutter 27 is fitted in the groove 26y. Thus, the cover 26 and the shutter 27 slide along the grooves 26y and the protrusions 27y.

  When the cover 26 and the shutter 27 slide, when the cover 27 and the shutter 26 are overlapped, each primary transfer portion is opened, and the primary transfer portion is covered with the shutter 27 by shifting the position of each other. Is possible. The distance between the cover 26 and the shutter 27 is adjusted so that the plurality of primary transfer portions are simultaneously opened or covered. Since the shutter 27 in each primary transfer portion is connected as described above, it can be slid on the cover 26 at the same time.

  As shown in FIG. 3B, the fixing member 16 is provided in the vicinity of the end portion 5 g of the intermediate transfer unit 5, and the cover 26 a of the primary transfer surface T end portion 5 g is fixed to the fixing member 16. A shutter pressing member 28 as an urging member is provided inside the cover 26a. As shown in FIG. 8, when the door 11 is closed, the shutter 27 overlaps the inside of the cover 26, so the primary transfer portion is opened, and the primary transfer surface T is in contact with each photosensitive drum 1 at that portion. . As the door 11 opens, the pressing member 28 provided on the back side of the cover 26a presses the end of the shutter 27a that overlaps the inside of the cover 26a, thereby tracing the groove 26y of the cover 26 described in FIG. Then, the shutter 27 slides to cover and protect the primary transfer surface T of the intermediate transfer member 5b.

  Here, the movement of the posture of the intermediate transfer unit 5 when the door 11 performs the opening / closing operation from the opened state of the door 11 shown in FIG. 3B to the closed state shown in FIG. 8 will be described. A shutter holding portion 38 is provided at the end 5h of the intermediate transfer unit 5 of the access door 11, and the shutter holding portion 38 and the shutter 27 are integrated or restrained. The shutter holding portions 38 do not exist in the entire region in the direction (width direction) intersecting the moving direction of the belt surface 5b during image formation, but are provided only at both ends thereof, and the belt 5b and the longitudinal length of the winding roller 5i are provided. It is provided so that it may overlap from the outside of the direction both ends. On the other hand, as shown in FIGS. 1 and 8, the apparatus main body is provided with abutting portions I that abut against the shutter holding portion 38 at both ends in the width direction of the belt 5b. Exists only in

  Therefore, as indicated by an arrow Q in FIG. 8, as the door 11 is closed, the shutter holding portion 38 abuts against the door 11 side of the abutment portion I, and thereafter, at the portion where the abutment portion I abuts. While being guided and sliding, it moves to the upper part, and the shutter 27 is gradually opened accordingly.

  On the contrary, when the closed state is changed to the open state, the stopper 29 which is integrated with the shutter 27 and is an L-shaped member in FIG. 3B abuts against the abutting portion J provided in the intermediate transfer unit 5. This prevents the shutter 27 from sliding more than necessary, and the shutter 27 can completely cover the plurality of covers 26 fixed to the intermediate transfer member 5b.

  That is, the shutter holding portion 38, the shutter 27, and the stopper 29 are integrated or restricted. Therefore, as described above, since these are interlocked, the stopper 29 comes into contact with the abutting portion J by the force from the urging member 28, and the shutter 27 and the holding portion 38 are also stopped when stopped. As shown in FIG. 4, the slide restricting means is configured such that a part of the fixed shutter 26 serves as a guide rail, and the sliding shutter 27 slides in the direction in which the belt 5b is stretched.

  On the other hand, the intermediate transfer unit 5 is detached from the door 11 by operating a unit mounting member 21 provided on the access door 11 side. The configuration of the mounting member 21 is omitted.

  FIG. 5 shows a state where the door 11 is fully opened and the intermediate transfer unit 5 is removed from the access door 11 by turning off the mounting of the mounting member 21. As in FIG. 3, an enlarged view is shown in FIG. As described above, since the shutter 27 and its holding portion 38 are attached to the exterior of the intermediate transfer unit 5, the intermediate transfer member 5b is covered and protected even when the user moves the intermediate transfer unit 5. Yes.

  In FIG. 7, as shown in detail in FIG. 8, when the door 11 is closed, the intermediate transfer unit 5 is automatically positioned with respect to the image carrier 1 and the transfer material conveyance path 20 on the image forming apparatus main body side. At the same time, when the shutter holding portion 38 provided near the fulcrum 12 side of the primary transfer surface T abuts against the abutting portion I provided in the image forming apparatus, the movable shutter 27 is moved as described above. Since the holding portion 38 is integrated with the holding portion 38, the holding portion 38 moves along the outer shape of the contact portion I indicated by the arrow Q as shown in FIG. Accordingly, the shutter 27 is pushed up in the direction of Fb in the drawing along the primary transfer surface T, the shutter 27 slides, and the shutter 27 so that the photosensitive drum 1 and the intermediate transfer member 5b can come into contact with each other through the gap between the covers 26. Is retracted inside the cover 26 as described above with reference to FIG.

  Here, since the intermediate transfer unit 5 is attached to the access door 11 in a floating state via the pressing members 14 and 15 as described above, the intermediate transfer unit 5 can be simply operated by the user closing the door 11. The abutting portion 16 provided at the end portion 5g on the 5th side and the abutting portion 17 provided at the end portion 5h of the unit 5 abut against the abutting members 18 and 19 provided inside the image forming apparatus main body, respectively. As the door 11 is closed, the pressing members 14 and 15 are elastically deformed as the doors 11 are closed. When the door 11 is completely closed, the positioning with respect to the image carrier 1 and the transfer material transport unit 20 is performed. Is performed automatically.

  At the same time, as described above, the holding portion 38 on the shutter 27 side comes into contact with the abutting portion 19 on the apparatus main body side at the I portion, and the shutter 27 slides, and as described above, Since the intermediate transfer member 5b is exposed at the primary transfer portion in the image forming portion S, the user can keep the intermediate transfer member 5b in a high quality state without requiring a special operation relating to the movement of the shutter 27.

  FIG. 8 is an enlarged view when the door 11 is closed, the intermediate transfer unit 5 is positioned with respect to the image carrier 1 and the transfer unit E, and the shutter 27 is opened. At this time, if the force by which the pressing member 28 presses the shutter holding portion 38 in parallel with the sliding direction of the shutter 27 by the pressing member 28 provided in the intermediate transfer unit 5 is Fs, the shutter holding portion 38 of the abutting portion I. If the reaction force acting on Fb is Fb, as explained above, since the holding portion 38 and the movable shutter 27 are integrated, a force acts like Fs by the pressing member 28, so the reaction force of Fb It becomes.

  In order for the shutter 27 to be opened when the intermediate transfer unit 5 comes into contact with the image carrier 1 and the transfer material conveyance unit 14, it is necessary to satisfy a relationship of Fb> Fs. That is, the pressing force Fs of the pressing member 28 is smaller than the reaction force Fb generated with the abutting portion I when the intermediate transfer unit 5 is positioned on the image forming apparatus.

  FIG. 9 is an enlarged view of the vicinity of the primary transfer portion on the primary transfer surface T, and a cover 26 and a shutter 27 fixed to the intermediate transfer unit 5 are arranged. When the distance between the two covers 26 adjacent to each other with the primary transfer portion interposed therebetween is lc and the length of the shutter 27 in the sliding direction is ls, the cover 27 is completely covered and protected by the shutter 27 between the covers 27. Requires a relationship of ls ≧ lc.

  In this way, usability and maintainability of the image forming apparatus are improved.

  As explained above, the intermediate transfer unit is provided with a shutter that covers and protects the intermediate transfer body by automatically interlocking with the opening and closing of the door by the pressing member provided on the intermediate transfer unit side. Sometimes, it is possible to prevent the intermediate transfer member from being damaged by a user's hand, a wristwatch, a ring or the like.

  Also, in the above door configuration, by allowing access from the same direction as the transfer material conveyance, if one access door is opened, the image forming unit such as the developing device, the intermediate transfer member, and the transfer material conveyance unit are exposed, The user can easily see the intermediate transfer unit, can directly access its constituent elements, and has high transfer material jam handling properties. At the same time, the user can be prevented from being damaged by improving the usability.

  Further, when the door is changed from the open state to the closed state, the shutter attached to the intermediate transfer unit with the pressing member is abutted against the abutting portion provided inside the image forming apparatus main body, and at least when the door is in the closed state. The image bearing member and the intermediate transfer member are completely retracted without hindering contact. On the other hand, when the door is changed from the closed state to the open state, the abutment is released, and the shutter completely covers the intermediate transfer body by the pressing force of the pressing member, so that the intermediate transfer unit can be detached and maintained. It is possible to prevent damage to the intermediate transfer member at the time.

  Here, the intermediate transfer type image forming apparatus has been described as an example, but also in the direct transfer type image forming apparatus, a transfer material conveying belt is provided in place of the intermediate transfer belt, and is provided by a door-side pressing member. If the cover and shutter are provided on the transfer surface in the same manner as in this embodiment, the present invention can be applied by making them detachable. However, in this case, the transfer material conveyance direction is different from the present embodiment.

  The number and configuration of the image forming units S are not limited to this, and an electrostatic recording image forming apparatus may be used.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to the present invention. FIG. 3 is a cross-sectional view showing an open / close member fully opened state of the image forming apparatus according to the present invention. FIG. 4 is a top view (FIG. 3A) and a cross-sectional view (FIG. 3B) showing an example of a transfer device and an opening / closing member according to the present invention. It is sectional drawing which shows an example of the transfer apparatus which concerns on this invention. FIG. 3 is a cross-sectional view illustrating a state in which the transfer device is attached to and detached from the opening / closing member of the image forming apparatus according to the present invention. It is the upper view (FIG. 6 (a)) and sectional drawing (FIG.6 (b)) which show an example of the transfer apparatus and opening / closing member which concern on this invention. FIG. 3 is a cross-sectional view showing an open / close member closed state of the image forming apparatus according to the present invention. FIG. 3 is a cross-sectional view showing an open / close member closed state of the image forming apparatus according to the present invention. It is an expanded sectional view showing a cover and a shutter concerning the present invention. It is sectional drawing which shows an example of the conventional image forming apparatus. It is sectional drawing which shows the open / close member full open state in an example of the conventional image forming apparatus.

Explanation of symbols

1 Photosensitive drum (image carrier)
5 Intermediate transfer unit (transfer device)
5b Intermediate transfer member (belt member)
11 Access door (opening / closing member)
26 Cover 27 Shutter 28 Shutter push-up member 38 Shutter holding member

Claims (4)

A plurality of image forming portions where a developer image is formed on the surface of each image carrier, and a belt body on which a surface facing the image carrier in the plurality of image forming portions moves during image formation; In an image forming apparatus that includes a transfer device that transfers an agent image to a transfer material, and an opening / closing member that opens the inside of the device, and the opening / closing member detachably mounts the transfer device to perform an opening / closing operation.
The transfer device includes a cover that covers a portion of the belt body surface other than the portion facing the image carrier in a fixed state, a shutter that automatically interlocks with opening and closing of the opening and closing member, and a shutter pressing that biases the shutter A member, and
Due to the pressing force of the shutter pressing member, the shutter is overlapped with the cover when the opening / closing member is closed, and thereby the belt body at the opposing portion of the belt body and the plurality of image carriers. The image is characterized in that the surface can come into contact with the image carrier, and when the opening / closing member is opened, the belt body moves in a direction to cover a portion of the belt body facing the image carrier at the time of image formation. Forming equipment.   The pressing force of the shutter pressing member that moves the shutter in a direction that covers a portion facing the image carrier at the time of image formation of the belt body is such that the shutter when the opening and closing member is closed covers the shutter. The image forming apparatus according to claim 1, wherein the force is smaller than a force for moving in a direction overlapping with the image forming apparatus.   The length of the shutter is longer than the distance where the cover is not installed in the belt body moving direction at a portion of the belt body surface facing the image carrier. Image forming apparatus.   4. The image forming apparatus according to claim 1, wherein the transfer device is held by the pressing member on the opening / closing member.

Images