JP4677083B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus such as a copying machine, a printer, or a facsimile that forms an image by an electrophotographic system or an electrostatic recording system, and more particularly to an intermediate transfer type image forming apparatus.
[0002]
[Prior art]
In recent years, as an electrophotographic multi-color or full-color image forming apparatus, a plurality of photosensitive drums are arranged in a row according to each color, and toner images of each color formed on each photosensitive drum are sequentially placed on an intermediate transfer member. A so-called in-line type image forming apparatus that forms a color image by superimposing has been put into practical use.
[0003]
FIG. 6 is a schematic configuration diagram showing an example of a full-color image forming apparatus (full-color copying machine in the figure) having an in-line type intermediate transfer member in a conventional electrophotographic system.
[0004]
The image forming apparatus includes a printer unit A and a reader unit B. The printer unit A includes an image forming unit 1Y that forms a yellow image, an image forming unit 1M that forms a magenta image, and a cyan color. The image forming unit 1C for forming the first image and the image forming unit 1Bk for forming the black image are provided with four image forming units (image forming units), and these four image forming units 1Y, 1M, and 1C are provided. , 1Bk are arranged in a line at regular intervals.
[0005]
In each of the image forming units 1Y, 1M, 1C, and 1Bk, drum-type electrophotographic photosensitive members (hereinafter referred to as photosensitive drums) 2a, 2b, 2c, and 2d are installed as image carriers. Around each photosensitive drum 2a, 2b, 2c, 2d, there are chargers 3a, 3b, 3c, 3d, developing devices 4a, 4b, 4c, 4d, transfer blades 5a, 5b, 5c, 5d, a drum cleaning device 6a, 6b, 6c, and 6d are installed, and exposure devices 7a, 7b, 7c, and 7d are installed above the chargers 3a, 3b, 3c, and 3d and the developing devices 4a, 4b, 4c, and 4d, respectively. Yes. Each developing device 4a, 4b, 4c, 4d contains yellow toner, magenta toner, cyan toner, and black toner, respectively.
[0006]
Each of the photosensitive drums 2a, 2b, 2c, and 2d is a negatively charged OPC photosensitive member having a photoconductive layer on an aluminum drum base, and is driven in an arrow direction (counterclockwise) by a driving device (not shown). It is rotationally driven at a predetermined process speed.
[0007]
The chargers 3a, 3b, 3c and 3d as charging means uniformly charge the surfaces of the photosensitive drums 2a, 2b, 2c and 2d to a predetermined negative potential by a charging bias applied from a charging bias power source (not shown). To do.
[0008]
The developing devices 4a, 4b, 4c, and 4d develop the toner images by making each color toner adhere to the electrostatic latent images formed on the photosensitive drums 2a, 2b, 2c, and 2d, respectively. . As a developing method using the developing devices 4a, 4b, 4c, and 4d, for example, toner particles mixed with a magnetic carrier are used as a developer and conveyed by a magnetic force, and are transferred to the photosensitive drums 2a, 2b, 2c, and 2d. On the other hand, a two-component contact development method in which development is performed in a contact state can be used.
[0009]
The transfer blades 5a, 5b, 5c and 5d as transfer means are made of an elastic member, and each of the primary transfer nip portions Ta, Tb, Tc and Td has an endless belt-like intermediate transfer body (hereinafter referred to as an intermediate transfer belt). 8) abutting the photosensitive drums 2a, 2b, 2c, and 2d through 8 respectively. The intermediate transfer belt 8 is stretched between the drive roller 9, the secondary transfer counter roller 10, and the tension roller 11, and is rotated (moved) in the arrow direction (clockwise) by the drive of the drive roller 9. The intermediate transfer belt 8 is made of a dielectric resin such as a polycarbonate, a polyethylene terephthalate resin film, a polyvinylidene fluoride resin film, or the like.
[0010]
The secondary transfer counter roller 10 is in contact with the secondary transfer roller 12 via the intermediate transfer belt 8 to form a secondary transfer portion Te. The secondary transfer roller 12 is installed so as to be able to contact and separate from the intermediate transfer belt 8. In the vicinity of the tension roller 11 outside the intermediate transfer belt 8, a belt cleaning device 13 that removes and collects transfer residual toner remaining on the surface of the intermediate transfer belt 8 is installed. In the belt cleaning device 13, a plate-like blade member 13 a made of an elastic member is installed in contact with the intermediate transfer belt 8. A fixing device 14 having a fixing roller 14a and a pressure roller 14b is installed on the downstream side of the secondary transfer portion in the transfer material conveyance direction.
[0011]
The drum cleaning devices 6a, 6b, 6c, and 6d remove and collect the transfer residual toner remaining on the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d, respectively, with a blade member.
[0012]
In the exposure devices 7a, 7b, 7c, and 7d, laser light modulated in response to time-series electric digital pixel signals of image information input from the reader unit B is output from a laser output unit (not shown), and high-speed By exposing the surface of each photosensitive drum 2a, 2b, 2c, 2d through a rotating polygon mirror (not shown) or the like, each photosensitive drum 2a, 2b, 2d, An electrostatic latent image of each color corresponding to the image information is formed on the surfaces 2c and 2d.
[0013]
The reader unit B includes a scanning unit 20 that irradiates and scans an image of an original (not shown), and scanning light (reflected light from the original) from the scanning unit 20 passes through an optical lens system 21. It is input to the CCD 22, converted into an electrical signal, subjected to processing such as color separation, and input to the exposure devices 7a, 7b, 7c, 7d of the printer unit A.
[0014]
Next, an image forming operation by the above-described image forming apparatus will be described.
[0015]
When an image formation start signal is issued, the photosensitive drums 2a, 2b, 2c, and 2d of the image forming units 1Y, 1M, 1C, and 1Bk that are rotationally driven at a predetermined process speed are respectively charged by the chargers 3a, 3b, and 3c. , 3d is uniformly negatively charged. Then, the exposure devices 7a, 7b, 7c, and 7d convert the color-separated image signals of the document (not shown) input from the reader unit B into optical signals at the laser output unit (not shown), respectively. Each of the photosensitive drums 2a, 2b, 2c, and 2d charged with the laser beam that is the converted optical signal is scanned and exposed to form an electrostatic latent image.
[0016]
First, yellow toner is adhered to the electrostatic latent image formed on the photosensitive drum 2a by the developing device 4a to which a developing bias having the same polarity as the charging polarity (negative polarity) of the photosensitive drum 2a is applied. Visualize as an image. This yellow toner image is rotated (moved) by the transfer blade 5a to which a primary transfer bias (opposite polarity (positive polarity) to toner) is applied at the primary transfer portion Ta between the photosensitive drum 2a and the transfer blade 5a. Primary transfer is performed on the intermediate transfer belt 8.
[0017]
The intermediate transfer belt 8 onto which the yellow toner image has been transferred is rotated (moved) toward the image forming unit 1M. In the image forming unit 1M, the magenta toner image formed on the photosensitive drum 2b in the same manner as described above is superimposed on the yellow toner image on the intermediate transfer belt 8 and transferred by the primary transfer unit Tb. Is done.
[0018]
In the same manner, cyan and black toner images formed by the photosensitive drums 2c and 2d of the image forming units 1C and 1Bk on the yellow and magenta toner images superimposed and transferred onto the intermediate transfer belt 8 in the same manner are respectively primary. A full color toner image is formed on the intermediate transfer belt 8 by sequentially superimposing at the transfer portions Tc and Td.
[0019]
Then, in accordance with the timing at which the front end of the full-color toner image on the intermediate transfer belt 8 is moved to the secondary transfer portion Te between the secondary transfer counter roller 10 and the secondary transfer roller 12, The transfer material (paper) P selected from the cassette 16 and fed through the transfer material transport unit 17 is transported by the registration roller 18 to the secondary transfer unit Te. At this time, the secondary transfer roller 12 is brought into contact with the secondary transfer counter roller 10 via the intermediate transfer belt 8. Then, a full-color toner image is collectively collected by the secondary transfer roller 12 to which a secondary transfer bias (a polarity opposite to the toner (positive polarity)) is applied to the transfer material P conveyed to the secondary transfer portion Te. Transcribed.
[0020]
The transfer material P on which the full-color toner image is formed is conveyed to the fixing device 14, and the full-color toner image is heated and pressed at the fixing nip between the fixing roller 14a and the pressure roller 14b to thermally fix it on the surface of the transfer material P. After that, the sheet is discharged onto the sheet discharge tray 19, and a series of image forming operations is completed.
[0021]
During the primary transfer described above, the primary transfer residual toner remaining on the photosensitive drums 2a, 2b, 2c, and 2d is removed and collected by the drum cleaning devices 6a, 6b, 6c, and 6d, respectively. . Further, secondary transfer residual toner or the like remaining on the intermediate transfer belt 8 after the secondary transfer is scraped and collected by the blade member 13a of the belt cleaning device 13.
[0022]
When obtaining a single color image (for example, a monochrome image), a visible image of a single color (monochrome image) is primarily transferred onto the intermediate transfer belt 8 from a specific image forming unit (for example, the image forming unit 1Bk). A monochromatic image can be obtained through a process similar to that for forming a full-color image.
[0023]
[Problems to be solved by the invention]
In an intermediate transfer type image forming apparatus, an endless belt-shaped intermediate transfer belt 8 is used as an intermediate transfer member as in the above-described image forming apparatus, so that a transfer material conveying unit 17, a secondary transfer unit Te, and a fixing device are used. A degree of freedom is created in the arrangement of 14 mag. Therefore, the transfer material conveyance path from the transfer material conveyance unit 17 to the fixing device 14 through the secondary transfer unit Te can be shortened, which is advantageous for downsizing the apparatus.
[0024]
However, since the transfer material transport unit 17, the secondary transfer unit Te, the fixing device 14 and the like are disposed close to each other due to the downsizing of the apparatus, the following occurs when the transfer material P is jammed. Problems arise.
[0025]
In other words, the image forming apparatus described above stops the image forming operation when the occurrence of a paper jam (jam) during image formation is detected by sensors (not shown) provided at various locations on the transfer material conveyance path. A message is displayed on a display panel (not shown) or the like so as to perform a paper jam clearing operation. At this time, the transfer material remaining in the apparatus is often held in a plurality of locations such as the secondary transfer portion Te and the fixing device 14 because the transfer material conveyance path is short.
[0026]
Accordingly, the user needs to remove the transfer material that has caused a paper jam in the transfer material conveyance path in the apparatus or the transfer material left in the apparatus because the image forming operation has stopped due to the occurrence of the paper jam. . At this time, particularly when the fixing device 14 and the secondary transfer portion Te are close to each other, when a paper jam occurs and the image forming operation is stopped, the transfer material is sandwiched between both the secondary transfer portion Te and the fixing device 14. There will be more cases.
[0027]
As a result, when the fixing device 14 is pulled out to perform the paper jam processing, the transfer material jammed with the secondary transfer portion Te is torn. Further, when a paper jam occurs near the entrance of the fixing device 14, an unfixed image is placed on the paper jam transfer material, and the paper jam transfer material may be torn with the secondary transfer portion Te. As a result, the inside and outside of the apparatus become dirty with unfixed toner.
[0028]
SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus that can easily perform jam processing without damaging a jammed transfer material.
[0029]
[Means for Solving the Problems]
In order to achieve the above object, one or a plurality of image carriers, a rotatable intermediate transfer member carrying a toner image transferred from the image carrier, and the intermediate transfer member are pressed to form a toner image. A transfer roller that constitutes a transfer portion that transfers from the intermediate transfer member to the transfer material, and a toner image that is disposed on the upstream side of the transfer roller in the transfer material conveyance direction and is carried on the intermediate transfer member is moved to the transfer portion. In accordance with the timing, a registration roller that conveys the transfer material to the transfer unit and a transfer material that is disposed downstream of the transfer roller in the transfer material conveyance direction and onto which the toner image is transferred are sandwiched between the transfer material and the toner image on the transfer material Fixing means, a first spring for urging the transfer roller in a direction in contact with the intermediate transfer member, a support member for supporting the first spring , the fixing means, and the support member. Hold and draw A holding member mounted outside the forming apparatus and capable of being pulled out in the transfer material conveying direction, and disposed between the transfer roller and the fixing unit, and the support member can be rotated with respect to the holding member. And a rotation support portion that is supported between the transfer roller and the fixing unit, and the support member is attached in a direction in which the transfer roller contacts the intermediate transfer body with the rotation support portion as a center. And a second spring to be biased.
[0030]
Further, the holding member can be pulled out of the image forming apparatus and in the transfer material conveyance direction along a guide rail that is movable in a substantially horizontal direction.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on the illustrated embodiments.
[0032]
<Embodiment 1>
FIG. 1 is a schematic configuration diagram showing an image forming apparatus according to Embodiment 1 of the present invention (in the figure, an electrophotographic inline-type full-color copying machine). The same members as those in the image forming apparatus of the conventional example shown in FIG. Also in the present embodiment, an image forming operation is performed in the same manner as the above-described conventional image forming apparatus. In this embodiment, description of the image forming operation is omitted.
[0033]
In this image forming apparatus, the laser light modulated in accordance with the time-series digital pixel signal of the image information output from each exposure device 7a, 7b, 7c, 7d passes through each reflection mirror 7e, 7f, 7g, 7h. Then, the surface of each photosensitive drum 2a, 2b, 2c, 2d is exposed to form an electrostatic latent image.
[0034]
Further, a pre-secondary transfer guide 30a for guiding the transfer material P to the secondary transfer portion Te is installed upstream of the secondary transfer portion Te in the transfer material transport direction, and the transfer material transport direction of the secondary transfer portion Te. A pre-fixing guide 30b for guiding the transfer material P, onto which the toner image has been transferred, to the fixing device 14 is installed on the downstream side.
[0035]
In the image forming apparatus of the present embodiment, as shown in FIGS. 2 and 3 (viewed from the direction of arrow A in FIG. 2), the pre-secondary transfer guide 30a and the pre-fixing guide 30b are formed of the concave member 30c. The secondary transfer roller 12 that is integrally formed as a support member and is located in the concave member 30c has an appropriate pressure (preferably 5880 to 15680 mN ) by each roller pressure spring 31 (first spring ). Then, the roller abuts against the secondary transfer counter roller 10 via the intermediate transfer belt 8 and is driven to rotate by frictional force with the intermediate transfer belt 8. Further, the secondary transfer roller 12 of the present embodiment is a metal roller having a diameter of 16 to 30 mm using an aluminum pipe or the like. The secondary transfer roller 12 may be an elastic roller such as urethane rubber.
[0036]
The secondary transfer counter roller 10 and each roller pressure spring 31 are held in a concave member 30c, and each roller pressure spring 31 is arranged between the concave member 30c and each bearing 12a at both ends of the secondary transfer roller 12. ing. In this embodiment, the secondary transfer bias to the secondary transfer roller 12 is configured to be applied from the secondary transfer counter roller 10, and the secondary transfer roller 12 is electrically grounded. Even when the secondary transfer bias is applied to the secondary transfer roller 12 and the secondary transfer counter roller 10 is electrically grounded, the effects of the present invention can be obtained. Further, the secondary transfer roller 12 may be driven to rotate by a pulse motor or the like in consideration of the transportability of the transfer material P at the secondary transfer portion Te.
[0037]
Both sides of the lower surface of the pre-fixing guide 30 b on the fixing device 14 side are rotatably held by the holding member 33 by the respective rotation shafts (rotation support portions) 32. Further, pressure springs 34 (second springs) are disposed on both sides between the pre-fixing guide 30b and the holding member 33, and the spring force of the pressure springs 34 (preferably 19.6 to 29.4N). By energizing the pre-fixing guide 30b, the secondary transfer roller 12 is brought into contact with the secondary transfer counter roller 10 via the intermediate transfer belt 8 with the appropriate pressure described above. The fixing device 14 and the paper discharge tray 19 are also fixed and held on the holding member 33.
[0038]
As shown in FIG. 3 (viewed from the direction of arrow A in FIG. 2 ), the holding member 33 has rail members 36 fixed to both side surfaces thereof, and each rail member 36 is a front plate 38 of the printer section A. And are movably mounted in rail support members 37 that are directly fixed to the inner wall of the rear plate 39 in the horizontal direction. Accordingly, the holding member 33, together with the held secondary transfer roller 12, the fixing device 14, the paper discharge tray 19, the secondary pre-transfer guide 30a, and the pre-fix guide 30b, is disposed outside the printer unit A and in the paper discharge direction ( It can be moved in the transfer material conveyance direction ( arrow B direction in FIG. 2 ).
[0039]
The holding member 33 has a handle portion 35. The user can easily pull out the holding member 33 by grasping and pulling the handle portion 35 by the user.
[0040]
Next, a description will be given of a measure in the present embodiment when a paper jam (jam) occurs during image formation.
[0041]
As shown in FIG. 4, the image forming operation is stopped due to a paper jam in a state where the transfer material (paper) P is held between both the secondary transfer portion Te and the fixing device 14 during the image forming operation. In this case, an unfixed toner image is placed on the surface of the transfer material P.
[0042]
When the apparatus is stopped, the transfer material P is also sandwiched between the registration roller pair 18 positioned upstream in the sheet passing direction of the secondary transfer portion Te (in this embodiment, the transfer material P is held between the registration roller pair 18. If it is recognized by sensors (not shown) arranged at various locations on the paper feeding path, for example, a paper jam process is performed on the display panel (not shown) of the device. Before urging to perform the transfer, it is desirable to convey the transfer material P, which is sandwiched by rotating the registration roller pair 18, downstream in the sheet passing direction until the nipping is released. Alternatively, it is desirable that the transfer material P can be reliably pulled out when the user pulls out the holding member 33 due to the registration roller pair 18 being separated from each other.
[0043]
When such a paper jam (jam) occurs, the user is notified by displaying on a display panel (not shown) or the like so as to perform a paper jam clearing operation.
[0044]
Then, as shown in FIG. 5, the user holds the handle portion 35 of the holding member 33 and pulls it in the paper discharge direction (arrow B direction), so that the rail members 36 on both sides of the holding member 33 are moved to the rail support members 37. The guide member 30 and the pre-secondary transfer guide 30 a and the secondary transfer roller 12, the pre-fixing guide 30 b, the fixing device 14, and the paper jammed transfer material P held by the holding member 33 are outside the printer unit A. Pulled out.
[0045]
In this way, the jammed transfer material P is pulled out of the printer unit A so that the user can easily take it out from above (in the direction of arrow C). Therefore, the secondary transfer roller 12 can be reduced in size. Even if the fixing device 14 and the fixing device 14 are close to each other, the jammed transfer material P is not torn and damaged, and the unfixed toner image on the jammed transfer material P is transferred inside and outside the printer unit A. The paper jam can be easily and quickly carried out. Further, by pulling out in the paper discharge direction, the transfer material P jammed in the secondary transfer portion can be pulled out without being torn between the intermediate transfer belt 8 and the secondary transfer roller 12.
[0046]
Further, by pulling out the holding member 33 to the outside of the printer unit A in addition to the above-described paper jam processing, maintenance and replacement of the secondary transfer roller 12 and the fixing device 14 on the holding member 33 can be easily performed. it can.
[0047]
【The invention's effect】
According to the present invention described above, since the holding member holding a transfer roller and the fixing means are and be pulled out freely mounted on the transfer material conveyance direction external to the image forming apparatus, a transfer unit near or even if a jam occurs between the fixing means near or transfer roller and the fixing unit, exposing the holding member and by withdrawing the transfer material conveying direction outside the image forming apparatus, the transfer roller and the fixing means to the outside of the image forming apparatus Therefore, even when the transfer roller and the fixing unit are close to each other due to miniaturization, the jammed transfer material can be easily removed without damaging the inside and outside of the apparatus with unfixed toner. It becomes.
[0048]
Further, by pulling out the holding member to the outside of the image forming apparatus, the transfer roller and the fixing unit can be exposed to the outside of the image forming apparatus, so that maintenance and replacement can be easily performed.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention.
FIG. 2 is a schematic diagram showing the vicinity of a fixing device and a secondary transfer portion of the image forming apparatus according to the embodiment of the present invention.
3 is a schematic view seen from the direction of arrow A in FIG.
FIG. 4 is a diagram illustrating a state in which a paper jam has occurred between the fixing device and the secondary transfer unit.
FIG. 5 is a diagram illustrating a state during a paper jam processing according to the embodiment of the present invention.
FIG. 6 is a schematic configuration diagram showing an image forming apparatus in a conventional example.
[Explanation of symbols]
1Y, 1M, 1C, 1Bk Image forming portions 2a, 2b, 2c, 2d Photosensitive drum (image carrier)
3a, 3b, 3c, 3d Charger 4a, 4b, 4c, 4d Developing device 5a, 5b, 5c, 5d Transfer blade 6a, 6b, 6c, 6d Drum cleaning device 7a, 7b, 7c, 7d Exposure device 8 Intermediate transfer belt (Intermediate transfer member)
12 Secondary transfer roller (transfer roller)
13 Belt cleaning device 14 Fixing device (fixing means)
30a Guide before secondary transfer 30b Guide before fixing 30c Concave member (30a, 30b, 30c support member)
31 Roller pressure spring (first spring)
32 Rotating shaft (Rotating support part)
33 Holding member 34 Pressure spring ( second spring)
36 Rail member 37 Rail support member 38 Front side plate 39 Rear side plate

Claims (2)

One or more image carriers;
A rotatable intermediate transfer member carrying a toner image transferred from the image carrier;
A transfer roller that constitutes a transfer unit that presses the intermediate transfer member to transfer a toner image from the intermediate transfer member to a transfer material;
A registration roller that is arranged upstream of the transfer roller in the transfer material conveyance direction and conveys the transfer material to the transfer unit in accordance with the timing at which the toner image carried on the intermediate transfer member is moved to the transfer unit;
A fixing unit disposed downstream of the transfer roller in the transfer material conveyance direction, sandwiching the transfer material onto which the toner image has been transferred, and fixing the toner image on the transfer material;
A first spring that urges the transfer roller in a direction in contact with the intermediate transfer member;
A support member for supporting the first spring ;
A holding member that holds the fixing unit and the support member, and is attached to the image forming apparatus so that the fixing unit and the support member can be pulled out in the transfer material conveyance direction;
A rotation support unit disposed between the transfer roller and the fixing unit, and rotatably supporting the support member with respect to the holding member;
A second spring that is disposed between the transfer roller and the fixing unit and biases the support member in a direction in which the transfer roller contacts the intermediate transfer body with the rotation support portion as a center. Prepared,
An image forming apparatus. The holding member can be pulled out to the outside of the image forming apparatus and in the transfer material conveyance direction along a guide rail that is movable in a substantially horizontal direction.
The image forming apparatus according to claim 1.

Images