JP4323927B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to a color image forming apparatus using an electrostatic recording system or an electrophotographic system, such as a printer for a computer or a copying machine.

  2. Description of the Related Art Conventionally, there are image forming apparatuses that perform image formation by an electrostatic recording method that electrostatically controls and adsorbs a developer containing fine powder or an electrophotographic method using electrophotographic technology. In such an image forming process, a latent image forming process for forming an electrostatic latent image on the surface of, for example, a photosensitive drum or a photosensitive belt, which is an image carrier, by an image forming unit; Development process with a toner or the like to make a visible image into a developer image (toner image), a transfer process in which the developed toner image is transferred onto a transfer material by a transfer device, and an image is carried, pressure or heat A fixing process that fixes the toner image on the transfer material onto the transfer material by a fixing device using the above, and an image formed product is obtained by sequentially performing these steps.

  By applying this technique, a plurality of color images, so-called color images, can be obtained by using a plurality of developers having different colors. In principle, if yellow, magenta, and cyan developers are used, a full color image can be obtained by color mixing. In some cases, a black developer is used in addition to these three types.

  As a configuration of a color image forming apparatus, a developing device for storing a developer is provided for each color, and the plurality of developing devices are arranged on a straight line or a curve to develop an electrostatic latent image corresponding to the developer of each color. is there. There are a direct transfer method and an intermediate transfer method as a method of superimposing a plurality of color images in a color image forming apparatus until a final image is obtained on a transfer material such as paper or a plastic sheet.

  In the former direct transfer method, a transfer material is a target to which a toner image on an image carrier adjacent to (or included in) a developing device is transferred in a transfer process. In other words, the direct transfer method forms an electric bias so that the developer on the image carrier is attracted to the transfer material when the transfer material is brought into contact with the image carrier or through a minute gap. In this method, an image is directly transferred from a transfer material to a transfer material. In a color image forming apparatus having a plurality of developing devices and a plurality of image carriers, the transfer material is moved to the opposite position of the image carrier corresponding to each color, and the toner images corresponding to each color are sequentially transferred to the transfer material. To do.

  On the other hand, in the latter intermediate transfer system, the second image carrier that holds all the toner images of the respective colors transferred from the image carrier to carry out the step of transferring the image from the image carrier to the transfer material. Is used. That is, in the transfer process, all the toner images are once held on the second image carrier from the image carrier on which the toner images corresponding to the respective colors have been developed, and the first and second image carriers are interposed. An electric bias is formed at the contact point between the second image carrier and the transfer material downstream from the transfer position, and the image is transferred from the second image carrier to the transfer material. This second image carrier is sometimes called an intermediate transfer member.

  A color image forming apparatus using an intermediate transfer method is more advantageous in terms of stability of a formed image than that using a direct transfer method. This is because when a single color toner image on the image carrier corresponding to each color is transferred in the next step, the developer must be superimposed, but in the direct transfer method, the developer is directly applied from the image carrier to the transfer material. Since the image is transferred, the transfer environment differs depending on the physical properties, thickness, stiffness, etc. of the transfer material, and it becomes unstable upon superposition. This is because the transferability of the transfer material also affects the image. At this time, depending on the attracting force of the transfer material, the developer already transferred to the transfer material may be reversely transferred to the downstream image carrier. On the other hand, in the intermediate transfer method, since the transfer object in the overlay process is always the same object, a stable overlay image can be obtained. Since the image is transferred from the intermediate transfer member to the transfer material at once, the transfer conditions may be set for the worst-case transfer material.

  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. At that time, in a plurality of developing devices, the developer is replenished or each developing device including the developer is replaced.

  However, the developing device applying the electrophotographic technology and the image carrier adjacent thereto are an exposure device for forming an electrostatic latent image on the image carrier (first image carrier), and the next step of the developer image. It is often arranged in a state surrounded by an intermediate transfer member (second image carrier) to be processed. For this reason, the developing device is often disposed at the center of the apparatus main body, and is disposed at a location that is difficult for the user to access.

  Also, due to some problem during image formation, the transfer material may stay and remain in the image forming apparatus main body.

  The transfer material transport process is as follows. The untransferred transfer material in the transfer material storage unit is supplied to the transfer point of the intermediate transfer member. Immediately after passing the transfer point, the image (developer image) is electrostatically adsorbed on the transfer material, and it is necessary to transport the transfer material to the fixing device in order to fix the developer. Note that the fixing device uses heat, pressure, or the like to melt and crush the developer constituting the developer image on the transfer material.

  Here, if the transfer material stays in the middle of the conveyance process, the image forming apparatus cannot be operated normally, and the user has to remove the transfer material in order to return from the normal operation.

  Furthermore, a defective image may be generated due to damage due to handling failure of the intermediate transfer member or deterioration due to long-term use. In order to obtain a good image, the intermediate transfer member must be repaired or replaced with a new one. For this purpose, it is necessary to remove the intermediate transfer member.

When considering these maintainability, an image forming unit including a plurality of developing devices 4 (4Y, 4M, 4C, 4BK) as in the image forming apparatus shown in FIG. When S (SY, SM, SC, SBK) is arranged in parallel in the horizontal direction, as shown in FIG. 9 , the internal component device can be accessed by one upper opening / closing member (access door) 11b. However, this increases the installation area of the device, limiting the installation location, and inconvenience as a result, such as being unable to access unless the user goes around when performing maintenance etc. of the device. There were many.

  For example, the conventional color image forming apparatus has the configuration shown in the schematic cross-sectional view of FIG. 8, and from the upper side of the apparatus, the exposure device 3, the developing device 4, and the photosensitive drum 1 (1Y, 1M, first image carrier). 1C, 1BK), the intermediate transfer member 5a, and the transfer material storage unit 6 are arranged in this order. A fixing device 8 is disposed downstream of the transfer material P.

  Here, FIG. 9 shows a state in which the access door 11b is opened, and the exposure apparatus 3 is mounted and integrated on the access door 11b side. On the fixed side A2 of the apparatus, an intermediate transfer unit (intermediate transfer unit) 5 including an image forming unit S such as a developing device 4 for each color and a photosensitive drum 1, a belt-like intermediate transfer member 5a, a winding roller 5i thereof, and the like is disposed. Has been. That is, since the access door 11b is disposed at the upper part and the intermediate transfer unit 5 is disposed at the lower part of the plurality of image forming units S, when the intermediate transfer member unit 5 is detached, as shown in FIG. The user must remove and remove all the image forming means such as the developing device 4 and the photosensitive drum 1 by opening the upper access door 11b. FIG. 10 shows a state in which the developing devices 4BK and 4C and the photosensitive drums 1BK and 1C are removed from the image forming apparatus.

  FIG. 11 is a schematic cross-sectional view of another conventional example described in Patent Document 2. This image forming apparatus also has a configuration in which a plurality of image forming units S including the developing device 4 are arranged in parallel in the horizontal direction, as shown in FIG. 8, but here, the intermediate transfer unit 5 is provided with each image forming unit. It is arranged above S. FIG. 12 is a perspective view when the access doors 11c and 11d are all closed. From this state, as shown in FIG. 13, the access doors 11c and 11d are provided on the image forming apparatus frame on the side surface of the image forming units S arranged horizontally. By opening the first access door 11c, it is possible to replenish each developer in each image forming section S and to detach the developing device 4 and the image carrier 1 from each other.

  However, in this image forming apparatus, when the detaching direction of the intermediate transfer unit 5 is set to the same detaching direction as the developing apparatus 4, it is necessary to provide a large hole for detaching on the side frame supporting the image forming apparatus. The rigidity of the device frame is extremely lost. Therefore, the intermediate transfer unit 5 must be attached / detached from another door 11d different from the first door 11c from which the developing device 4 is attached / detached.

FIG. 14 shows the second access door 11d opened and the intermediate transfer unit 5 partially removed. Similarly, in order to ensure the rigidity of the apparatus frame, for example, the transfer material should be jammed from a third door (not shown) just opposite to the second door 11d.

  As described above, in a color image forming apparatus having a plurality of developing devices, the replenishment of the developer, the replacement of the developing device, the removal of the transfer material staying in the conveyance path, or the replacement of the intermediate transfer member, etc. In order to perform maintenance, an access door must be provided. Therefore, in the conventional example, in order to maintain a certain device component, there is an inconvenience that a component that does not need to be maintained must be removed from the device. there were. In addition, it is often necessary to provide a plurality of doors for accessing each means to be maintained.

In any conventional example, the user has to perform complicated operations.
Japanese Patent Laid-Open No. 08-016046 Japanese Patent Application Laid-Open No. 08-220823

  SUMMARY OF THE INVENTION An object of the present invention is to provide an entire internal configuration of an image forming apparatus with a small number of opening / closing operations in an intermediate transfer type image forming apparatus having a plurality of color developing devices, without providing more openings and sizes than necessary. By providing an image forming apparatus that can perform maintenance such as developer replenishment or replacement of a developing device, transfer material removal processing, and adjustment of an intermediate transfer member without requiring many operations. is there.

The above object is achieved by the image forming apparatus according to the present invention. In summary, the present invention provides a plurality of image carriers on which images are formed, an intermediate transfer member on which images formed on the plurality of image carriers are transferred, and an open / close that can be opened and closed with respect to the apparatus main body. An image forming apparatus having a rotation center at a lower end thereof,
The intermediate transfer member is held only by the opening / closing member during the opening operation of the opening / closing member, and moves together with the opening operation by rotation around the rotation center of the opening / closing member, in the open state, the intermediate transfer body Ri detachable der respect to the closing member,
The intermediate transfer member has a rotation center at one end of the intermediate transfer member on the upper end side of the opening / closing member, and the intermediate transfer member rotates with respect to the opening / closing member in the open state of the opening / closing member. There is provided an image forming apparatus characterized in that the other end of the intermediate transfer member opposite to the rotation center can be moved downward by rotating around the center .

An image forming apparatus according to the present invention includes a plurality of image carriers on which images are formed, an intermediate transfer member to which images formed on the plurality of image carriers are transferred, and an opening / closing member that can be opened and closed with respect to the apparatus main body. In the image forming apparatus in which the opening / closing member has a rotation center at its lower end, the intermediate transfer member is held only by the opening / closing member during the opening operation of the opening / closing member, and rotates around the rotation center of the opening / closing member. It is intended to move with the opening operation by the movement, and, in the open state of the closing member, the intermediate transfer body Ri detachable der against closing member, the intermediate transfer member, the intermediate transfer an upper end side of the opening and closing member When the opening / closing member is in the open state, the other end opposite to the rotation center of the intermediate transfer body is obtained by rotating around the rotation center of the intermediate transfer body with respect to the opening / closing member. since the end is movable downwardly, as (1) opening and closing member When the access door is opened, the intermediate transfer member is held on the door side, and the visibility of the intermediate transfer member, image carrier, image forming means such as a developing device, paper transport path, etc. is greatly improved. This not only facilitates replacement of the photosensitive drum, developing device, and intermediate transfer body unit, but also reduces the number of access doors, and allows easy operation to maintain image forming means and transfer material transport paths. Is possible. As a result, the usability of the image forming apparatus is improved.

  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 shows a schematic configuration of the image forming apparatus of the present embodiment according to the present invention. In this embodiment, the image forming apparatus is a color image forming apparatus A using an electrophotographic system, and is a laser beam printer capable of forming a full-color image of four colors. Then, an image is formed through an image forming process in which an image visualized with a developer (for example, toner) is fixed to a transfer material by heat or the like.

  The color image forming apparatus A is a photosensitive drum 1 (1Y, 1M, 1C, 1BK) that is a drum-type electrophotographic photosensitive member as a first image carrier for each color (yellow, magenta, cyan, black) to be formed. ). Each photosensitive drum 1 is rotated by a driving means (not shown), for example, counterclockwise in FIG.

  A charging device 2 (2Y, 2M, 2C, 2BK), which is a charging unit that uniformly charges the surface of the photosensitive drum 1 in the charging process as an image forming unit around the photosensitive drum 1 in the rotation direction. A latent image forming unit (exposure unit) that forms a static latent image on the photosensitive drum 1 by blinking a light source (for example, laser light or LED light) based on image information in an image forming step (exposure step). In the exposure device 3 (3Y, 3M, 3C, 3BK), a developer image (toner) is visualized (developed) by attaching toner as a developer to the electrostatic latent image on the photosensitive drum 1 in the developing process. A developing device 4 (4Y, 4M, 4C, 4BK) that is a developing means for forming an image), and an intermediate transfer member 5a as a second image carrier to which the toner image on the photosensitive drum 1 is transferred in the transfer step. Including an intermediate transfer unit (intermediate transfer unit) 5 etc. There. The intermediate transfer member 5a constituting the intermediate transfer unit 5 has a belt shape and rotates clockwise.

  Here, the image forming means such as the photosensitive drum 1, the charging device 2, and the developing device 4 are integrated for each color to form an image forming unit S (SY, SM, SC, SBK). The image forming unit S is fixedly arranged in parallel to the intermediate transfer unit 5 in the vertical direction. The developing device 4 that develops the electrostatic latent image on the photosensitive drum 1 includes a developer accommodating portion 41 that accommodates toner for each color. Each developer container 41 carries a toner as a developer on its surface, and is a developer carrier that faces the photosensitive drum 1 and moves the toner from the developer container 41 to the photosensitive drum 1. An agent carrying roller 42 is provided so that the electrostatic latent image on the photosensitive drum 1 can be developed by the developer carrying roller 42.

  By sequentially transferring and superimposing the toner images on the photosensitive drums 1 for the respective colors onto the intermediate transfer member 5a facing each other, one full-color toner image electrostatically adsorbed on the intermediate transfer member 5a is formed. Incidentally, in order to transfer the toner from the photosensitive drum 1 to the intermediate transfer member 5a, transfer means 5d (5dY, 5dM, 5dC, 5dBK) for generating an electric bias facing each photosensitive drum 1 is used as an intermediate transfer as a belt. It is provided on the opposite side of the photosensitive drum 1 across the body 5a.

  After forming one toner image on the intermediate transfer member 5a, the intermediate transfer member 5a carries the toner image and further rotates to the transfer portion E to the transfer material P. On the other hand, the transfer material P in the transfer material storage box 6 is supplied to the transfer location E by the feeding / conveying device 7 at a predetermined timing. At this transfer location E, a transfer means 5e for generating an electric bias with respect to the transfer belt 5a is provided on the opposite side of the intermediate transfer member 5a across the conveyance path of the transfer material P.

  In this way, the toner image is transferred to the transfer material P using the electrostatic attraction force. Further, in order to fix the toner image to the transfer material P in the fixing process, the transfer material P is conveyed to a fixing device 8 which is a fixing unit. In the fixing device 8, the toner on the transfer material P is melted and fixed using heat and pressure.

  The transfer material P that has passed through the fixing device 8 is discharged to the paper discharge tray 10 by the transport unit 9. The transfer material P is transported from the fixing device 8 to the paper discharge tray 10 along a transport path 20 that is a curve from the bottom surface to the top surface.

  By the way, as described in the conventional example, in a color image forming apparatus having a plurality of image forming units S, in the developing device 4 provided in each image forming unit S, replenishment of developer, replacement of the developing device, An open / close member (access door) must be provided in order to perform maintenance of the color image forming apparatus such as removal of the transfer material P staying in the conveyance path or replacement of the intermediate transfer body 5a. In the example, in order to maintain a certain device component, there is a trouble that a component that does not need to be maintained must be removed from the device. In addition, it is often necessary to provide a plurality of doors for accessing each means to be maintained.

  Therefore, in the present invention, the color image forming apparatus can be maintained by a simple operation of the user.

The first embodiment of the present invention is implemented in the above-described image forming apparatus having the configuration shown in FIG. As described above, the image forming units are arranged in the vertical direction, and the intermediate transfer member 5a vertically extends along the primary transfer unit of each image forming unit S on the belt surface Ta on which the primary transfer of each color toner image is performed. The belt surface Ta is formed so as to move from below to above. As shown in FIG. 2, the access door 11 is provided in the side surface vertical direction, and is installed in the same direction as the belt surface Ta with the fulcrum 12 at the lower end in the cross section as the rotation center (FIG. 2 (a )) And is opened so that the upper end 13 of the door 11 is directed downward (FIG . 2B) .

When the access door 11 is opened, it is substantially parallel to the surface formed in the transfer material movement trajectory direction before and after the portion where the image is transferred from the intermediate transfer member 5a to the transfer material P during image formation. it is preferable direction to the opening and closing member is rotated. This is because, first, the intermediate transfer member 5a must be in contact with the transfer material conveyance path in the image forming apparatus. As device maintenance user, there is a transfer material jam of the transfer material conveyance path. Therefore, it is necessary to move the intermediate transfer member 5a arranged close to the conveyance path.

  Here, as a feature of the present invention, in the relationship between the access door 11 and the internal configuration of the image forming apparatus, the photosensitive drum 1 and the intermediate transfer body unit 5 are divided at the boundary, and the divided intermediate transfer body unit 5 is divided. It is mentioned that the part is held by the access door 11. Therefore, the user can move to the following maintenance operation by performing only the operation of opening one door.

  (1) In the transfer path 20 of the transfer material P, it is assumed that the transfer material P is jammed between the transfer material storage unit 6 to the intermediate transfer member 5a and the image transfer unit E to the transfer material P to the fixing device 8. . In this case, the visibility of the user is ensured for all the transport paths 20 by opening one access door 11. Therefore, the user can easily perform jam processing.

  (2) As shown in FIG. 3, the parts constituting the image forming unit S, in particular, any pair of the developing device 4 and the photosensitive drum 1 can be attached and detached without interfering with other constituent parts.

  (3) As shown in FIG. 4, when the access door 11 is opened, the intermediate transfer unit 5 is exposed together with the access door 11, so that the intermediate transfer unit 5 can be attached and detached by opening the access door 11. Since there is no interfering component and it is in the user's field of view, the visibility is good and it is possible to easily replace the components related to the intermediate transfer unit 5 such as the intermediate transfer unit 5 or the intermediate transfer body 5a. .

Here, as shown in FIG. 5, it is preferable that the relative positions of the intermediate transfer unit 5 and the door 11 differ depending on the open / closed state of the access door 11. That is, in the normal state where the door 11 is not opened at the relative position between the intermediate transfer unit 5 and the door 11 (FIG. 2A), the transfer surface Ta is in contact with all the image forming portions S. The intermediate transfer unit 5 that does not change even when the door 11 is opened can be shifted from the position 5f to the position 5g. Here, in the normal state (FIG. 2A), the intermediate transfer unit 5 rotates with a roller 5b (for example, also serving as a tension roller) of the upper intermediate transfer member 5a as a fulcrum. In such a case, the relative position of the intermediate transfer unit 5 with respect to the door 11 can be changed by the movement of the door 11, thereby expanding the visible range inside the apparatus and improving the maintainability of the image forming apparatus for the user. Further improvement can be achieved . Thereby , the movement of the intermediate transfer unit 5 can be made different from the rotation trajectory of the door 11, and the field of view in the intermediate transfer unit 5 is expanded. 2 to 5 show a configuration in which the intermediate transfer unit 5a is wound around the two rollers 5b and 5c in the intermediate transfer unit 5 for convenience, but the three tension rollers 5b, The same applies to the case of being wound at 5c, and any one of the two lower rollers 5c may be used as a fulcrum that moves on the door 11. As described above, the adjustment is appropriately made according to the configuration of the image forming apparatus A.

  As another method, the relative position can be changed by the weight of the intermediate transfer unit 5. For example, only the upper part of the intermediate transfer unit 5 is supported by the door 11, and as the door is opened, the shift between the support shaft and the center of gravity of the intermediate transfer unit 5 increases, and the intermediate transfer unit 5 gradually tilts. By utilizing this inclination, the intermediate transfer unit 5 held by the door 11 may be set so that the position of the intermediate transfer unit 5 is lowered downward so that the intermediate transfer unit 5 can be easily taken out by the user. That is, when the access door 11 is opened and closed, the movement amount of the intermediate transfer unit 5 is larger than the movement amount of the access door 11.

  As an example, the intermediate transfer unit 5 is held by the access door 11 near the roller 5b. Further, the vicinity of the roller 5c does not move with respect to the access door 11. For example, the intermediate transfer unit 5 is pressed by a lever (not shown) attached to the frame of the image forming apparatus. When the access door 11 is closed, the intermediate transfer unit 5 can remain in the image forming position by the lever. If the access door is opened and the lever stops pressing the intermediate transfer unit 5, the intermediate transfer unit 5 with the access door 11 open is held near the roller 5b and suspended in the air. For example, the shape near the roller 5c is lowered by gravity.

  Since the intermediate transfer unit 5 is held by the door 11, the moving speed of the intermediate transfer unit 5 becomes constant in conjunction with the opening and closing of the door 11 in a natural state. By not changing the relative speed between the door 11 and the intermediate transfer unit 5 by changing the installation state of the intermediate transfer unit 5 to the door 11 as described above, various operations can be performed during the opening / closing operation of the door 11. Functions can be incorporated. For example, the opening / closing operation of the door 11 can be used to detach the rotational drive connection to the intermediate transfer unit 5 or to avoid interference between the intermediate transfer unit 5 and other internal components.

  In the intermediate transfer unit 5, the driving source of the intermediate transfer member 5 a is a photosensitive drum that is an image carrier in the provided image forming unit S, here, at least one of the four image forming units S. If it is the same as the driving source 1, the rotation synchronization can be easily achieved, and if the rotation synchronization is established, deterioration in image transfer can be prevented. For example, if the rotation driving source of the photosensitive drum 1BK and the intermediate transfer member 5a is shared in the black image forming unit SBK, the transfer property of the black formed image is remarkably improved. Further, if not only black but also the yellow photosensitive drum 1Y, the magenta photosensitive drum 1M, and the cyan photosensitive drum 1C are synchronized by the same drive source, image reproducibility is improved with respect to color superposition.

  However, if either the intermediate transfer member 5a or the photosensitive drum 1 is the same drive source and the intermediate transfer member 5a moves by opening the door 11, the intermediate transfer member 5a or the photosensitive drum 1 is in the middle of the drive path. In addition, a drive attaching / detaching mechanism is required. When the image forming unit S is arranged vertically as in this embodiment, the belt-shaped intermediate transfer body 5a is generally stretched between two tension rollers 5b and 5c arranged in the vertical direction. When the image forming unit S is disposed on the side, the image transfer property from the photosensitive drum 1 to the intermediate transfer member 5a is better. In the case of the configuration of FIG. 1, the roller 5b on the upper side of the intermediate transfer unit 5 in the normal state often takes the belt drive. The intermediate transfer unit 5 can be easily moved by operating the drive attaching / detaching mechanism of the intermediate transfer member 5a in conjunction with the opening of the door 11.

  In the present embodiment, the reason why the image forming unit S is arranged in the vertical direction is that, in the image forming apparatus in which a plurality of image forming units S as shown in FIGS. As a result, the installation area is limited, the installation location is limited, and the user cannot access unless the user goes around when performing maintenance of the apparatus. However, even in the case where the image forming unit S is horizontally arranged, the present invention can be applied by installing the intermediate transfer unit 5 on the upper side and holding the intermediate transfer unit 5 on the upper access door.

  Further, the transfer material conveyance direction angle after passing through the transfer portion E with respect to the first position (transfer portion) E where the toner image is transferred from the intermediate transfer body 5a to the transfer material P is transferred before passing. It is preferable that the angle is shallower than 45 ° above the material conveyance angle. The reason and composition will be described below.

  After the transfer to the transfer material P, the intermediate transfer member 5a must transfer and hold a new image from the photosensitive drum 1 again. On the other hand, the toner on the intermediate transfer member 5a is not 100% transferred to the transfer material, and may remain on the intermediate transfer member 5a as the transfer residual toner. If the toner adheres to the transfer portion with the photosensitive drum 1 as it is, it overlaps with a new image and the image quality deteriorates. In order to prevent this image deterioration, a cleaning member 5h for the intermediate transfer member 5a must be disposed between the transfer point to the transfer material P and the transfer point with the photosensitive drum 1 on the path of the intermediate transfer member 5a. There is.

  Further, a good image can be obtained under the condition that the transfer material conveyance direction angle is 45 ° or less before and after the transfer portion to the transfer material. Further, when the cleaning member 5h is disposed at a transfer material conveyance direction angle of 45 ° or more, if the inclination of the transfer material P becomes 45 ° or more, an unfixed image on the transfer material P is transferred to the cleaning member 5h. There is a risk of rubbing.

Reference Example FIGS. 6 and 7 show a reference example of the present invention. FIG. 6 is a perspective view of an image forming apparatus B of this reference example which is an image forming apparatus having the same configuration as that of the color image forming apparatus in FIG. 1 except for the number of tension rollers 5b and 5c in the intermediate transfer unit 5. A cross section is illustrated from the side of the apparatus. The internal configuration is the same as that of the first embodiment. In this reference example , as shown in FIG. 7, the access door 11a is opened by rotating in the horizontal direction about the vertical direction. In this case, the effect obtained is the same regardless of whether it opens to the left or right.

Also in this reference example , the intermediate transfer unit 5 is supported by the door 11a, and the image forming unit S including the intermediate transfer unit 5, the photosensitive drum 1, the developing device 4, and the like, and the transfer material conveyance path are opened by opening the door 11a. Both 20 are sufficiently visible from the user.

As described above with reference to Example 1, according to the present invention, with respect to internal components of a color image forming apparatus, for carrying an image obtained by developing the division point of the access door from the electrostatic latent image By providing at least one door by holding the intermediate transfer member on the access door side at the contact portion between the image carrier and the intermediate transfer member, developer replenishment or development device replacement, transfer material removal processing, intermediate transfer member Maintenance such as adjustment can be performed.

  Further, in this door configuration, since it can be accessed from the same direction as the transfer material conveyance, if one access door is opened, the developing device, the intermediate transfer member, and the transfer material conveyance unit are exposed. And all the above-mentioned parts can be put into a user's view, and the component can be accessed directly.

1 is a schematic sectional view illustrating an example of an image forming apparatus according to the present invention. It is explanatory drawing which shows the opening / closing operation | movement of the opening / closing member in an example of the image forming apparatus which concerns on this invention. It is explanatory drawing which shows the state which the opening-and-closing member in an example of the image forming apparatus which concerns on this invention opened. It is explanatory drawing which shows the state which the opening-and-closing member in an example of the image forming apparatus which concerns on this invention opened. It is explanatory drawing which shows the state which the opening-and-closing member in an example of the image forming apparatus which concerns on this invention opened. FIG. 5 is a perspective view showing a state in which an opening / closing member is closed in a reference example of the image forming apparatus according to the present invention. FIG. 6 is a perspective view showing a state in which an opening / closing member is opened in a reference example of the image forming apparatus according to the present invention. It is a schematic block diagram which shows an example of the conventional image forming apparatus. It is explanatory drawing which shows the state which the opening-and-closing member in an example of the conventional image forming apparatus opened. FIG. It is explanatory drawing which shows the state which the opening-and-closing member in an example of the conventional image forming apparatus opened. FIG. It is a schematic block diagram which shows the other example of the conventional image forming apparatus. It is a perspective view which shows the state which the opening-and-closing member in the other example of the conventional image forming apparatus closed. It is explanatory drawing which shows the state which the opening-and-closing member in the other example of the conventional image forming apparatus opened. It is explanatory drawing which shows the state which the opening-and-closing member in the other example of the conventional image forming apparatus opened.

Explanation of symbols

1 (1Y, 1M, 1C, 1BK) Photosensitive drum (image carrier)
4 (4Y, 4M, 4C, 4BK) Developing device (image forming means)
5 Intermediate transfer unit (intermediate transfer unit)
5a Intermediate transfer member 11, 11a Access door (opening / closing member)
20 Transfer material transport path P Transfer material S (SY, SM, SC, SBK) Image forming portion E Transfer portion

Claims (1)

A plurality of image carriers on which images are formed, an intermediate transfer member to which images formed on the plurality of image carriers are transferred, and an opening / closing member that can be opened and closed with respect to the apparatus body, In the image forming apparatus having a rotation center at the lower end of the opening / closing member,
The intermediate transfer member is held only by the opening / closing member during the opening operation of the opening / closing member, and moves together with the opening operation by rotation around the rotation center of the opening / closing member, in the open state, the intermediate transfer body Ri detachable der respect to the closing member,
The intermediate transfer member has a rotation center at one end of the intermediate transfer member on the upper end side of the opening / closing member, and the intermediate transfer member rotates with respect to the opening / closing member in the open state of the opening / closing member. An image forming apparatus , wherein the other end of the intermediate transfer member opposite to the center of rotation is movable downward by rotating around the center .

Images