JP2006163381A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the effect of the weight of a fixing means at the opening and closing time of any of open-close means differing in releasing direction. <P>SOLUTION: An image forming apparatus includes: a fixing unit to fix an image formed on a recording material; a first open-close means releasing a conveying path to convey the recording material to the fixing unit; and a second open-close means releasable upward in a vertical direction together with an intermediate transferring member. When the first open-close member and the second open-close member are opened, the fixing unit is disposed on the image forming apparatus main body. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a full-color copying machine or printer that employs an electrophotographic system.

  In recent years, as a multi-color or full-color image forming apparatus using an electrophotographic system, a plurality of photosensitive drums 100 are arranged in a line for each color and formed on each photosensitive drum 100 as shown in FIG. The respective color toner images are sequentially superimposed on the intermediate transfer belt 101 to form a color image, which is secondarily transferred to a conveyed sheet (recording material), and then heat-fixed by the fixing means 102 and discharged to the discharge tray 103. Japanese Patent Application Laid-Open Nos. 2001-242680, 2003-202728, and 2004-85899 disclose so-called in-line type image forming apparatuses. These arrangements in which the exposure device is arranged on the lower surface side shorten the moving distance from the transfer of the toner image from the image forming unit to the intermediate transfer member to the transfer of the toner image to the recording material. This configuration is effective for shortening the first copy time.

  In such an image forming apparatus, in the image forming apparatus configured as described above, a unit having a sheet conveyance path can be rotated as a front door unit 104 in order to remove a jammed sheet in the sheet conveyance path. The sheet conveyance path from the cassette to the fixing device can be opened.

  On the other hand, since the recording material may be wound around the intermediate transfer belt 101, it is desirable to open the intermediate transfer belt. In particular, Japanese Patent Application No. 0865893 discloses a configuration in which a door for opening the conveyance path and a door for exchanging the image forming unit are provided, but the intermediate transfer member is not sufficiently opened. It was difficult to wind the recording material around the intermediate transfer member.

Correspondingly, as shown in FIG. 7B, as disclosed in Japanese Patent Application Laid-Open No. 2004-85899, the discharge tray 102, so as to easily handle the winding of the sheet around the intermediate transfer belt 101, An upper door unit 103 having an intermediate transfer belt 101 is configured to be rotatable with respect to the image forming apparatus main body. As a result, the conveyance path can be easily accessed by opening the front door unit 104, and the intermediate transfer can be performed by rotating the upper door unit 104 upward (in the direction of arrow C in FIG. 7B). Access to the belt 101 is facilitated. As a result, it is possible to improve the jam handling property of the sheet conveyance path.
JP 2001-242680 A JP 2003-202728 A JP 2004-85899 A Japanese Patent Registration No. 0865893

  However, in such a configuration in which the opening / closing member for opening the conveyance path and the opening / closing member for opening the intermediate transfer member are provided, the following problems occur when the fixing unit is attached to any of the opening / closing members. That is, when attached to an opening / closing member that can be opened and closed in the vertical direction, there is a problem that the stability at the time of opening is applied due to the weight of the fixing means at the time of opening, and when the fixing means is attached to the opening / closing cover on the side surface, It is necessary to increase the rigidity of the opening / closing cover so as to withstand it, and there is a problem that the configuration becomes complicated.

  An object of the present invention is to reduce the weight load of the fixing device when the conveyance path and the intermediate transfer member are opened by an opening / closing member.

An image forming unit having an image carrier, an intermediate transfer member disposed above the image forming unit, onto which a toner image formed by the image forming unit is transferred, and a toner image transferred from the intermediate transfer member to a recording material A fixing unit that is fixed by heat;
A recording material conveying path for conveying the recording material toward the fixing unit via a transfer unit for transferring the toner image of the intermediate transfer member to the recording material; a first opening / closing means for opening the recording material conveying path; An image forming apparatus comprising: a second opening / closing means that moves integrally with the body to expose the intermediate transfer body; and at least a fixing unit, a first opening / closing means, and an image forming apparatus main body that supports the second opening / closing means. The fixing unit is supported by the main body of the image forming apparatus when the opening / closing means and the second opening / closing means are open.

  Access to the conveyance path and the intermediate transfer member can be facilitated by opening the opening / closing member without being affected by the weight of the fixing unit.

  Hereinafter, the present invention will be described more specifically with reference to examples. Although these examples are examples of the best mode of the present invention, the present invention is not limited to these examples.

  Hereinafter, the present invention will be described more specifically with reference to examples.

(First embodiment)
1 to 6 show an embodiment. The printer is a color image forming apparatus having four colors of yellow (Y), magenta (M), cyan (C), and black (BK).

{Overall configuration of image forming apparatus}
First, the overall configuration of the image forming apparatus will be described with reference to FIG. FIG. 1 is a schematic sectional view of an image forming apparatus.

  The image forming apparatus shown in FIG. 1 is a photosensitive drum (105Y, 104M, 103C) that is an image carrier that forms toner images of each color of yellow (Y), magenta (M), cyan (C), and black (K). , 102K) are arranged. Around each photosensitive drum, a charger for charging the photosensitive drum, a developing unit for developing the electrostatic latent image formed by exposure, and a cleaning member for cleaning the toner on the photosensitive drum after transfer are arranged. These are unitized as process cartridges (105, 104, 103, 102) which are image forming units. Above these process cartridges, an intermediate transfer belt 101 as an example of a belt body as an intermediate transfer body is disposed so as to be in contact with each photosensitive drum.

  An exposure unit 112 is provided below the process cartridge to selectively expose each photosensitive drum by irradiating a laser corresponding to an image signal.

  Each photoconductor drum is charged by a charger, and an optical image of each color of yellow, magenta, cyan, and black is exposed by an exposure unit 112, and the electrostatic latent image of yellow, magenta, cyan, and black is exposed on the photoconductor drum. Form an image. Each electrostatic latent image is developed by a developing device to form yellow, magenta, cyan, and black toner images on the photosensitive drum.

  As the photosensitive drum rotates, the toner image reaches a primary transfer portion where the photosensitive drum and the intermediate transfer belt 101 come into contact with each other. The toner images are sequentially transferred to the intermediate transfer belt 101 by primary transfer rollers (102a, 103a, 104a, and 105a) that are primary transfer members disposed to face the respective photosensitive drums 1. A primary transfer bias set in advance from the electrical substrate is applied to the primary transfer roller.

  The recording material stored in the feeding cassette 107 loaded in the lower part of the apparatus body in synchronization with the image formation is fed one by one by the feeding roller, and the timing is adjusted by the registration roller 113, and then the sheet is fed. Transport to secondary transfer section. In the secondary transfer portion, a secondary transfer roller 114 constituting a secondary transfer unit is in contact with the intermediate transfer belt 101 and is driven to rotate. When the sheet is conveyed to the secondary transfer portion, a bias image is applied to the secondary transfer roller 114, whereby the toner images on the intermediate transfer belt 101 are collectively transferred to the sheet.

  Thereafter, the sheet on which the toner image has been transferred is conveyed to a fixing unit 1 which is a fixing unit composed of a fixing roller 1a which is an image heating member and a pressure roller 1b which is a pressure member, and receives heat and pressure there. Thus, the toner image on the recording material is fixed. As a result, the toner of each color is melted and mixed to form a full-color print image fixed on the sheet P, and then discharged to a discharge tray 110 which is a recording material stacking unit by a discharge roller pair 115 provided downstream of the fixing unit. The

  In the image forming apparatus according to the present embodiment having the above-described configuration, the feeding cassette 107, the exposure unit 112, the process cartridge, the intermediate transfer belt 101, and the discharge tray 110 are arranged in this order from the lower side to the upper side of the apparatus body. For this reason, a sheet conveyance path, which is a conveyance path, is formed so that the sheet is conveyed from below to above.

  Also, a main power supply substrate for controlling the fixed power source and the entire image forming apparatus is disposed in the apparatus main body. This electrical substrate can be arranged in a space formed between the exposure means 112 and the feeding cassette 107.

  Further, the surface connecting the primary transfer portions, which are the opposed portions of the four photosensitive drums 1 and the intermediate transfer belt 101, is configured to be inclined with the secondary transfer portion side downward. In the present embodiment, the inclination angle is set to about 15 °, and accordingly, each process cartridge and the exposure means 112 are also inclined at the same angle.

  In the image forming apparatus according to this embodiment, the right side in FIG. 1 is the front side of the apparatus, and the user performs various operations from the front side of the apparatus.

{Opening and closing part}
Next, an opening / closing part that can be opened and closed with respect to the apparatus main body will be described.

  As shown in FIG. 3, the image forming apparatus according to the present embodiment has a front door unit 120 serving as a first opening / closing means disposed on the front side of the apparatus main body. The front door unit 120 can also be rotated around the support shaft 4 with respect to the apparatus main body, and the front side of the apparatus main body can be opened and closed by rotating.

  A secondary transfer roller 114 is disposed on the front door unit 120. As shown in FIG. 3, when the front door unit 16 is opened, the sheet conveyance path is exposed, and the jammed sheet can be easily removed. It is like that. Further, the support shaft 4 is disposed at the lower part of the apparatus main body, and when the upper part of the front door unit 120 is rotated and opened, the sheet conveying path is greatly opened.

  Reference is now made to FIG. An upper door unit 130 as a second opening / closing means is disposed on the upper part of the apparatus main body. The upper door unit 130 can be rotated around a support shaft 131 with respect to the apparatus main body, and the upper part of the apparatus main body can be opened and closed by rotating.

  An intermediate transfer unit in which the intermediate transfer belt 101 is unitized is attached to the upper door unit 130. For this reason, as shown in FIG. 6, when the upper door unit 130 is opened, the process cartridge including the photosensitive drum is exposed, and the process cartridge can be replaced (removed) by a guide portion for attaching and detaching the process cartridge. It becomes possible. Further, since the intermediate transfer belt 101 disposed in the upper door unit 130 is also exposed, the replacement can be easily performed.

  Here, in the image forming apparatus according to the present embodiment, the upper door unit 130 is configured to be opened only when the front door unit 120 is opened.

  That is, as shown in FIG. 6, the upper door unit 130 is opened by turning upward on the main body about the support shaft 131. At this time, the upper part of the front door unit 120 is configured to protrude toward the upper door unit 130.

  Therefore, if the upper door unit 130 is opened with the front door unit 120 closed, the rotation locus of the upper door unit 130 interferes with the front door unit 16. On the other hand, when the front door unit 120 is in an open state, the interference is eliminated and the upper door unit 130 can be opened.

  When closing the front door unit 120, the front door unit 120 is closed after the upper door unit 130 is closed, contrary to the case of opening.

  That is, in the image forming apparatus of the present embodiment, the upper door unit 130 can be opened and closed only when the front door unit 120 is open.

  In addition, as described above, the primary transfer surface can be inclined and provided in an excess space created below the exposure 112, which is an advantage of the inclined arrangement, in the depth direction or width direction of the image forming apparatus. By accommodating the various electrical boards that should have been used, the volume of the entire image forming apparatus can be reduced.

  Next, a recording material jam processing method in this embodiment will be described. In this embodiment, the recording material conveyed from the cassette is conveyed to the fixing unit 1 via the registration roller and the secondary transfer unit. On the other hand, the secondary transfer unit is in contact with the intermediate transfer member. In such a configuration, the recording material may cause a paper jam in the conveyance path. In this case, it is possible to remove a recording material in the transport path by opening the front door 120. On the other hand, the recording material may be directed toward the intermediate transfer belt. In this case, the intermediate transfer belt can be opened by opening the upper door 130, and the jamming of the recording material near the intermediate transfer belt can be easily performed.

  As described above, in the configuration in which the conveyance path is opened by one opening / closing means and the intermediate transfer member is opened by another opening / closing means, each may be opened each time the jamming of the recording material is performed. Therefore, if the fixing unit is provided in any one of the opening / closing means, the following problem occurs. If it is provided on the front door side, the weight of the front door becomes heavy, so it is necessary to increase the rigidity of the front door. On the other hand, when it is provided on the upper door, not only does the load when opening the upper door increase, but it is also necessary to increase the rigidity of the upper door. Further, since the upper door is provided with an intermediate transfer belt, there is a possibility that the upper door is closed due to the weight of the fixing unit when the upper door is closed. There is also a risk of damaging the drive transmission system.

  In order to avoid such a problem, in the present invention, the fixing unit is left in the main body of the image forming apparatus regardless of which opening / closing means is open.

{Fusing unit rotation}
The fixing unit 1 has a rotation center 2 in a main body portion close to the fixing unit 1 and rotates to have two positions. That is, when both the upper door and the front door are closed, the position where fixing is possible (first position), and when either the upper door or the front door is open, another position (second position). Position). Thus, by making it possible to move to another position, it is possible to increase the efficiency of the processing operation when the recording material is jammed in the fixing unit. In addition, when the fixing unit is replaced, the exchangeability can be improved by setting the second position.

  A rotation mechanism of the fixing unit will be described.

  As shown in FIG. 5, the fixing unit 1 has a pressurizing mechanism that can release the pressure by the lever 11 and the springs 12 and 13, and can release and pressurize the pressure by the operation of the lever 11.

  Like the fixing unit 1, the front door 120 has a rotation center 4 in the main body and performs an opening / closing operation. The rotation center 4 of the front door 120 is located at the lower front of the main body, which is different from the rotation shaft 2 of the fixing device, so that a large open space can be taken.

  The front door 2 has a hook, and when the front door is closed, the hook is hooked at a different position in the thrust direction of the rotary shaft 2 of the fixing unit 1 to determine the position at the time of setting with respect to the main body. By doing so, the position when the front door 120 is set with respect to the fixing unit 1 can be accurately determined. In the front door opening operation, the front door 120 is opened by removing the hook from the rotary shaft 2. In the fixing unit 1, the lever 11 is urged by the spring 12 by the wall at the top of the main body at the first position, and presses the fixing by the spring 13.

  As described above, the fixing device can be held at the first position by the holding member 14, and the performance of the fixing device is guaranteed at this position (FIG. 5).

  Next, in the second position, the lever 11 is released to release the pressure (when the fixing device is opened). From the above description, when a jam occurs during the printing operation, the user can easily recognize the jammed paper when the jammed paper is first fixed by opening the front door 120 (FIG. 2). In conjunction with the rotation of the fixing device (to the second position), the nip is released and the user pulls the paper for jamming (FIG. 3). After the jam processing, the fixing unit 1 is set (to the first position) and the front door 120 is closed (FIG. 4).

  As described above, the jam handling performance is also improved, and it is possible to eliminate the pressure applied when simultaneously closing the fixing unit 1 having the rotation center 2 closer to the front door 120, so that the closing force when the front door 120 is closed can be reduced. became.

  Next, the unit replacement method will be described. First, the user can know the replacement time of each unit from the message on the main unit. The unit that needs to be replaced is replaced by the user.

  In this embodiment, the following replacement unit will be described. First, a case where the process cartridges 102 to 105 are removed will be described.

  In order to replace the process cartridges 102 to 105 that need to be replaced, it is necessary to open the upper door 130 in the pulling direction from the main body. However, since the front door 120 and the fixing unit 1 are on the rotation locus of the upper door 130, they cannot be opened as they are. Therefore, first, after the front door 120 is rotated and opened, the fixing unit 1 is moved to the second position. Therefore, the front door 120 and the fixing unit 1 can be detached from the turning locus of the upper door 130 and the upper door 130 can be opened (FIG. 6). Since the upper door 130 holds the intermediate transfer member 101, when the upper door 130 is opened, the intermediate transfer member 101 above the process cartridges 102 to 105 is similarly opened. Therefore, process cartridges 102 to 105 appear.

  The fixing unit 1 is located at the second position from the locus of inserting and removing the frontmost process cartridge 102. In this state, the process cartridges 102 to 105 that need to be replaced are pulled out in the direction of the arrow in FIG. Thereafter, a new process cartridge is prepared, and the process cartridges 102 to 105 are loaded into the stations designated by colors.

  When the intermediate transfer member 101 needs to be replaced, the intermediate transfer member can be transferred from the upper door 130 by pressing the left and right buttons of the intermediate transfer member 101 installed at the lower part of the sheet discharge tray with the upper door 130 opened. Since 101 is unlocked, the user can remove it by pulling the unit forward.

  In the second position, the fixing unit 1 can be replaced from the main body by removing the lever and removing the lever holding the rotation center 2.

  The new process cartridges 102 to 105, the intermediate transfer member 101, and the fixing unit 1 are set in the reverse order of removal, and the paper discharge tray 110, the fixing unit 1, and the front door 120 are closed, and the replacement operation is completed.

  Through the above operation, the user can easily replace each consumable unit even though it is a small machine.

  In this embodiment, the paper discharge tray is installed on the upper door 130, but it goes without saying that there is no problem if a separate paper discharge tray is provided.

  Further, in this embodiment, the description has been given of the printer in which the original image reading apparatus for reading the original image is not attached, but there is no problem even in the configuration in which the original reading apparatus is attached.

  In addition to the fixing unit, an image heating device that heats the image on the recording material can be considered. However, since this image heating device is relatively lighter than the fixing unit, it is attached to each opening / closing part. However, the load on the switching part does not increase. Of course, there is no problem even if the structure is attached to the main body of the image forming apparatus.

  According to the present invention, access to the conveyance path and the intermediate transfer member is facilitated by opening the opening / closing member without being affected by the weight of the fixing unit.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the technical idea of the present invention.

Sectional view of the image forming apparatus of the present invention Jam processing of the present invention FIG. Jam processing of the present invention FIG. Return diagram after jam processing of the present invention Conceptual diagram of fixing device pressure release mechanism of the present invention Implementation diagram of the present invention Conventional image forming apparatus

Explanation of symbols

1 Fixing Unit 101 Intermediate Transfer Belt 105Y, 104M, 103C, 102K Photosensitive Drum 120 Front Door Unit 130 Upper Door Unit

Claims (6)

An image forming unit having an image carrier, an intermediate transfer member disposed above the image forming unit, onto which a toner image formed by the image forming unit is transferred, and a toner image transferred from the intermediate transfer member to a recording material A fixing unit that is fixed by heat;
A recording material conveying path for conveying the recording material toward the fixing unit via a transfer unit for transferring the toner image of the intermediate transfer member to the recording material; a first opening / closing means for opening the recording material conveying path; An image forming apparatus comprising: a second opening / closing means that moves integrally with the body to expose the intermediate transfer body; and an image forming apparatus main body that supports at least the fixing unit, the first opening / closing means, and the second opening / closing means.
An image forming apparatus, wherein the fixing unit is supported by the main body of the image forming apparatus when the first opening / closing means and the second opening / closing means are open.   2. The image forming apparatus according to claim 1, wherein the first opening / closing means is disposed on a side surface of the image forming apparatus, and the second opening / closing means is disposed on an upper surface of the image forming apparatus.   The image forming apparatus according to claim 1, wherein the fixing unit is rotatable when at least one of the opening / closing means is opened.   4. The image forming apparatus according to claim 1, wherein the fixing unit is rotatable when the first opening / closing means is opened.   The fixing unit includes a heating member that heats the toner image on the recording material, and a pressure member that presses the heating member to sandwich and convey the recording material, and the heating member and the pressure member are interlocked with the rotation of the fixing unit. The image forming apparatus according to claim 1, wherein the pressure is reduced. 6. The image forming apparatus according to claim 1, wherein the image forming unit includes a plurality of image forming units, and the image forming unit is detachable from an opening portion formed by the second opening / closing unit.

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