JP2000305392A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the workability in jamming processing and to prevent a jamming from occurring again because a user forgets to close a jamming release cover in the case of removing jammed paper by opening the jamming release cover when a paper jamming occurs in a fixing part. SOLUTION: The jamming release cover 2 to which an upper carrying guide plate 3, a press-contact roller 4 and a spring 18 are attached is turnably attached to the main body part of a fixing device 217. Namely, the cover 2 is turnably attached to the side surface of the upper frame 10 of the fixing device so that it can be opened to the outside in a state where a (rotation) supporting point 5 provided at the end on the inner side (rear side) of an opposite side to the pulling-out direction of the upper frame 10 is set as an axis. The cover 2 is opened by turning on a horizontal plane from this side (front side) in the case of pulling out the device 217.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus provided with a fixing unit having a jam clearing cover (including a conveyance guide plate and a pressure roller) and pulling out the fixing unit during jam processing.

[0002]

2. Description of the Related Art In a conventional image forming apparatus such as a copying machine or a facsimile, when a paper jam occurs, a fixing unit is pulled out to perform jam processing. Hereinafter, the procedure of the conventional jam clearing method will be described. First, the fixing unit 301 is pulled out (see FIG. 5A). Next, the roller rotation knob 302 is turned to feed and remove the jammed paper 303 (see FIG. 5B). If it cannot be removed by this operation, as shown in FIG. 6, open the upper conveyance guide plate 312 to which the pressing roller 311 is attached in the direction of the arrow in FIG. 6, check the jammed paper, and pull the roller while pulling the paper. Turn the rotary knob to remove. Upper transport guide plate 3
The twelve rotation fulcrums 313 are provided on the front fixing frame and the rear fixing frame, and have a structure that is opened by rotation in a vertical plane. The upper transport guide plate 312 has a structure of closing by its own weight, but may be urged in a closing direction by using an elastic member such as a spring.

[0003]

At this time, when the upper conveyance guide plate 312 is released, a structure (spring,
In the case of returning by its own weight), a very difficult operation of turning the roller rotation knob 302 while holding the upper conveyance guide plate 312 and pulling the paper is required during the jam processing. The openings are small and you must look into the paper to check for jams. This was very poor workability.

Further, in the case of a structure in which the upper transport guide plate 312 is rotated and the upper transport guide plate 312 is not returned to the original position even when the upper transport guide plate 312 is released (rotated to a position where it is not returned to its original position by its own weight)
There is a case where the operator forgets to return the upper transport guide plate 312 to the original position after the jam processing, which may cause a jam again.

SUMMARY OF THE INVENTION It is an object of the present invention to improve the operability of jam clearance and to close the jam clearance cover when the jam clearance cover is opened to remove paper when a paper jam occurs in the fixing unit. An object of the present invention is to provide an image forming apparatus that prevents a jam from reoccurring due to forgetting.

[0006]

According to the first aspect of the present invention, when a paper jam occurs in a fixing unit for fixing an image by heating a sheet, the fixing unit is pulled out of the apparatus main body, and the fixing unit main body is fixed. This is an image forming apparatus for removing a sheet by opening a jam release cover attached to the image forming apparatus. The jam processing cover is provided so as to be openable in a horizontal plane around a fulcrum provided at the end of the fixing unit main body on the inner side of the drawer, and is disposed close to the apparatus main body. .

According to a second aspect of the present invention, the jam processing cover is provided with a pressing roller and an upper conveying guide plate, and the fixing unit main body is provided with a conveying roller and a lower conveying guide.

According to a third aspect of the present invention, the jam processing cover is provided with a pressing guide on the side in contact with the apparatus main body and near the open end.

According to a fourth aspect of the present invention, a magnet is provided on at least one of the jam processing cover and the fixing unit main body, a portion facing the magnet is a magnetic member, and the closed state of the jam processing cover is maintained by magnetic force. It is characterized by the following.

According to a fifth aspect of the present invention, the fixing unit main body is constituted by two releasable frames of an upper frame and a lower frame, and a fulcrum of the jam processing cover is provided on one of the upper frame and the lower frame. It is characterized by being provided.

The invention according to claim 6 is characterized in that the material of the jam processing cover is a heat-resistant resin.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic front sectional view showing a configuration of a digital color copying machine 1 which is an image forming apparatus according to the present invention. A document table 111 and an operation panel are provided on an upper surface of the copying machine main body 1, and an image reading section 110 and an image forming section 2 are provided inside the copying machine main body 1.
10 is provided. On the upper surface of the platen 111, the platen 111 is supported so as to be openable and closable with respect to the platen 111,
A two-sided automatic document feeder (RADF: Reversing Automatic Docucu
ment Feeder) 112 is mounted.

Further, the automatic two-sided automatic document feeder 112
First, the document is conveyed such that one surface of the document faces the image reading unit 110 at a predetermined position on the document table 111,
After the image reading for this one side is completed,
The original is inverted so that the other surface faces the image reading unit 110 at a predetermined position on the original
To be conveyed toward. Then, after the two-sided image reading for one document is completed, the double-sided automatic document feeder 112 discharges this document and performs a double-sided conveyance operation for the next document. The operation of conveying the document and reversing the front and back is controlled in relation to the operation of the entire copying machine.

The image reading section 110 is arranged below the document table 111 for reading an image of the document conveyed onto the document table 111 by the automatic duplex document feeder 112. The image reading unit 110 includes original scanning bodies 113 and 1 that reciprocate in parallel along the lower surface of the original table 111.
14, an optical lens 115, and a photoelectric conversion element CC
And a D line sensor 116.

The original scanning bodies 113 and 114 are composed of a first scanning unit 113 and a second scanning unit 114. The first scanning unit 114 has an exposure lamp for exposing the surface of the document image and a first mirror for deflecting a reflected light image from the document in a predetermined direction. It reciprocates in parallel at a predetermined scanning speed while maintaining the distance. The second scanning unit 114 has second and third mirrors for further deflecting the reflected light image from the document deflected by the first mirror of the first scanning unit 113 in a predetermined direction. It reciprocates in parallel with one scanning unit 113 while maintaining a constant speed relationship.

The optical lens 115 reduces the reflected light image from the document deflected by the third mirror of the second scanning unit, and forms the reduced light image at a predetermined position on the CCD line sensor 116. It is. The CCD line sensor 116 photoelectrically converts the formed light image in order and outputs it as an electric signal. CCD line sensor 116
Reads a black and white image or a color image,
A three-line color C that can output line data that is color-separated into each color component of (red), G (green), and B (blue)
It is a CD. The document image information converted into an electric signal by the CCD line sensor 116 is further transferred to an image processing unit (not shown) and subjected to predetermined image data processing.

Next, the configuration of the image forming unit 210 and the configuration of each unit related to the image forming unit 210 will be described.
Below the image forming unit 210, there is provided a paper feed mechanism 211 that separates sheets (recording media) P stacked and accommodated in a sheet tray one by one and supplies the separated sheets to the image forming unit 210. The paper P separated and supplied one by one is
The timing is controlled by a pair of registration rollers 212 disposed in front of the image forming unit 210 and the image forming unit 2
It is transported to 10. Further, the sheet P on which an image is formed on one side is re-supplied and conveyed to the image forming unit 210 in synchronization with the image formation of the image forming unit 210.

Below the image forming section 210, a transfer / conveying belt mechanism 213 is disposed. The transfer / transport belt mechanism 213 is provided between the drive roller 214 and the driven roller 215 to extend substantially in parallel with the transfer / transport belt 21.
6, the paper P is electrostatically attracted and transported. Further, the transfer and transport belt mechanism 2 in the paper transport path
A fixing device 217 for fixing the toner image transferred and formed on the sheet P to the sheet P is disposed downstream of the fixing device 13. The sheet P that has passed through the nip between the pair of fixing rollers of the fixing device 217 is transferred to the conveyance direction switching gate 2.
After that, the paper is discharged by a discharge roller 219 onto a paper discharge tray 220 attached to the outer wall of the copying machine main body 1.

The switching gate 218 is connected to the sheet P after fixing.
Is selectively switched between a path for discharging the sheet P to the copying machine main body 1 and a path for re-supplying the sheet P toward the image forming unit 210. The sheet P whose transport direction has been switched again toward the image forming unit 210 by the switching gate 218 is turned upside down via the switchback transport path 221, and then the image forming unit 210 is turned over.
Is supplied again. Further, above the transfer conveyance belt 216 in the image forming unit 210, the transfer conveyance belt 21 is provided.
6, the first image forming station Pa, the second
Image forming station Pb, third image forming station Pc, and fourth image forming station Pd,
They are arranged in order from the upstream side of the paper transport path.

The transfer conveyance belt 216 is driven by a driving roller 214.
As a result, the sheet P is frictionally driven in the direction indicated by the arrow Z in FIG. 1 and is gripped by the sheet P fed through the sheet feeding mechanism 211 as described above.
Conveyed sequentially to Pd. Each image station Pa to Pd
Have substantially the same configuration. Each of the image stations Pa, Pb, Pc, and Pd is a photosensitive drum 222a, 222b, 2 that is driven to rotate in the direction of arrow F shown in FIG.
22c and 222d.

Around the photosensitive drums 222a to 222d, chargers 223a, 223b, 223c, 22 for uniformly charging the photosensitive drums 222a to 222d, respectively.
3d and developing devices 224a and 224 for developing electrostatic latent images formed on the photosensitive drums 222a to 222d, respectively.
4b, 224c, 224d and transfer dischargers 225a, 225b, 225c, 225d for transferring the developed toner images on the photosensitive drums 222a to 222d to the paper P.
Cleaning devices 226a, 226b, and 2 for removing toner remaining on photoconductor drums 222a to 222d.
26c and 226d are photosensitive drums 222a to 222d.
Are sequentially arranged along the rotation direction.

Each of the photosensitive drums 222a to 222d
Above is a laser beam scanner unit (hereinafter, referred to as
LSU) 227a, 227b, 227c, 227d are provided respectively. LSUs 227a to 227d are:
A semiconductor laser device (not shown) for emitting dot light modulated in accordance with image data, a polygon mirror (directing device) 240 for deflecting a laser beam from the semiconductor laser device in the main scanning direction, and a polygon mirror 240 The laser beam deflected by the photosensitive drums 222a to 222a
It is composed of an fβ lens, a mirror, and the like for forming an image on the 22d surface.

A pixel signal corresponding to the black component image of the color original image is stored in LSU 227a, and a pixel signal corresponding to the cyan color component image of the color original image is stored in LSU 227b.
A pixel signal corresponding to the magenta color component image of the color original image is input to SU 227c, and a pixel signal corresponding to the yellow color component image of the color original image is input to LSU 227d.

As a result, an electrostatic latent image corresponding to the color-converted document image information is formed on each of the photosensitive drums 222a to 222d. The developing device 224a receives the black toner, the developing device 224b receives the cyan toner, the developing device 224c receives the magenta toner, and the developing device 224c.
24d contains yellow toner respectively, and the electrostatic latent images on the photosensitive drums 222a to 222d are:
The image is developed with the toner of each color. As a result, the document image information color-converted by the image forming unit 210 is reproduced as a toner image of each color.

A paper-suction (brush) charger 228 is provided between the first image forming station Pa and the paper feeding mechanism 211. And the sheet feeding mechanism 211
The sheet P supplied from the first image forming station Pa is securely sucked onto the transfer / conveying belt 216.
To the fourth image forming station Pd without shifting. On the other hand, a static eliminator (not shown) is provided almost directly above the drive roller 214 between the fourth image station Pd and the fixing device 217. An AC current is applied to the static eliminator to separate the paper P electrostatically attracted to the conveyor belt 216 from the transfer conveyor belt 216.

In the digital color copying machine having the above configuration, cut sheet-shaped paper is used as the paper P. The sheet P is sent out from the sheet cassette and fed to the sheet feeding mechanism 2.
When the paper P is fed into the guide of the paper feed conveyance path 11, the leading end of the paper P is detected by a sensor (not shown),
It is temporarily stopped by the pair of registration rollers 212 based on a detection signal output from this sensor. The paper P is transferred to the transfer conveyor belt 2 rotating in the direction of arrow Z in FIG.
16 is sent. At this time, since the transfer conveyor belt 216 has been given a predetermined charge by the attraction charger 228 as described above, the paper P is transferred to each image station Pa.
ＰPd is stably conveyed and supplied.

In each of the image stations Pa to Pd, a toner image of each color is formed, and is superposed on the support surface of the paper P conveyed by being electrostatically attracted and conveyed by the transfer conveyance belt 216. Fourth image station Pd
Is completed, the paper P is sequentially transferred from the leading end portion thereof to the transfer / conveying belt 216 by the negative discharger.
It is peeled off from above and guided to the fixing device 217. Finally, the paper P on which the toner image has been fixed is discharged onto a paper discharge tray 220 from a paper discharge port (not shown).

Next, the configuration of the fixing device 217 and the jam processing will be described. FIG. 2 is a sectional view of the fixing device housed in the apparatus main body, and FIG. 3 is a perspective view of the fixing device pulled out from the apparatus main body. Note that the fixing device 217 is pulled out of the image forming apparatus main body to the front side during the jam processing to perform the jam processing.

As shown in FIG. 2, the fixing device 217 is accommodated in the main body of the device and performs a fixing operation. Fixing device 217
Is heated by the upper and lower heat rollers 20 and 21 to fix the toner image formed on the sheet, guided by the transfer roller 216. Heat roller 20, 2
1 transports the sheet to upper and lower transport guide plates 3 and 16 and transports the sheet to a discharge tray by a pressure roller 4 provided on the upper transport guide plate 3 and a fixing transport roller 17 provided on the lower transport guide plate 16. Is done. Here, an oil application roller 23 and a cleaning roller 24 are in contact with the upper heat roller 20. The pressing roller 4 is urged downward by a spring 18, and can sandwich the sheet between the pressing roller 4 and the fixing and conveying roller 17. As shown in FIG. 3, the fixing and conveying roller 17 can be manually rotated by a roller rotation knob 19.

As shown in FIGS. 2 and 3, the fixing device 217 includes an upper frame 10 and a lower frame 11 which form a fixing device main body.
0, an oil application roller 23 and a cleaning roller 24 are fixed.
1, the lower conveyance guide plate 16 and the fixing conveyance roller 17 are fixed. The upper frame 10 is rotatable about the rotation support shaft 12 in the direction of arrow A (vertical direction) in FIG. Upper and lower heat rollers 20,
The shaft to which 21 is attached is fixed to a recess provided in the upper and lower frames 10 and 11 by a holding plate spring 22. At the time of work such as replacement of the heat rollers 20 and 21, the fixing device 217 is pulled out from the apparatus main body frame 15 (in the direction B in FIG. 3), and the upper and lower frames 10 and 11 can be opened and separated. Can be done with

The jam release cover 2 to which the upper transport guide plate 3, the pressure roller 4 and the spring 18 are attached is attached to the main body of the fixing device 217 so as to be rotatable in the direction of arrow C in FIG. That is, the jam release cover 2
Is rotated about a (rotational) fulcrum 5 provided at a rear (rear side) end of the fixing device opposite to the pull-out direction of the upper frame 10 so as to open outward on a side surface of the upper frame 10. Mounted as possible. This fulcrum will be described in detail. As shown in FIG. 4, the fulcrum 5 is composed of an upper fulcrum 5a and a lower fulcrum 5b on the upper frame, and the jam release cover 2 rotates about an axis connecting the upper and lower fulcrums. The lower fulcrum 5b is a portion in which a lower protrusion of the jam release cover 2 is inserted into a hole formed in the upper frame 10 so as to be rotatable. The upper fulcrum 5a is a portion in which the upper protrusion of the jam release cover 2 is inserted into a hole of the fulcrum plate 14 fixed to the upper frame 10 with a screw so as to be rotatable. As a result, the jam processing cover 2 is opened from the near side (front side) where the fixing device 217 is pulled out by rotation in a horizontal plane (see FIG. 3). When the jam release cover 2 is closed, the jam release cover 2 is positioned by the engagement between the positioning pins 6 and the positioning holes 7.

When the jam processing cover 2 has such an opening mechanism, a large opening is formed at the front of the apparatus, so that the user can easily recognize the jammed sheet during the jam processing, Removal work is also easy. Further, since the jam processing cover 2 is opened by the rotation in the horizontal plane, even if the user does not hold the jam processing cover 2, the cover 2 does not close by its own weight, and the jam of the user is prevented. Processing operation is easy.

Further, the jam processing cover 2 of the fixing device 217 has a structure in which a drawer front side (front side) is opened outward by a fulcrum 5 provided on the back side of the drawer.
When the fixing device 217 is stored, the jam processing cover 2
Are arranged close to the main body frame 15 of the image forming apparatus. For this reason, after the fixing device 217 is pulled out of the image forming apparatus main body frame 15 and a jam process is performed,
When the fixing device 217 is housed in the apparatus main body and returned to the original position, even if the jam processing cover 2 is kept open, the jam processing cover 2 and the main body frame 15 of the image forming apparatus come into contact with each other. The jam processing cover 2 is rotated in the closing direction. In this way, when the fixing device 217 is housed in the apparatus main body, the jam processing cover 2 is closed by the main body frame 15 acting as a guide member.
The trouble caused by forgetting to close does not occur.

Further, when the jam processing cover 2 is in a closed state, it is necessary to hold the jam processing cover 2 so as not to open it without permission. In the case where such a holding mechanism is to be obtained by, for example, an engagement member provided on the jam processing cover 2 side and the fixing device main body side (frame side), the jam processing cover 2 is closed immediately before it is completely closed. In addition, it is necessary to be pushed into the fixing device 217 by a certain force. In order to realize this, the pressing guide rib 8 may be formed near the open end on the side where the jam processing cover 2 contacts the main body frame 15. The pressing guide rib 8 is used for the main body frame 15 of the image forming apparatus.
, The jam processing cover 2 is securely closed.

In addition to the above configuration, a magnet 9 is provided on at least one of the jam processing cover 2 and the frames 10 and 11 of the fixing device 217 (a portion facing the magnet is a magnetic member). The following advantages are obtained when the closed state is maintained. That is,
In this configuration, when the jam processing cover 2 closes to a certain extent by the abutment when the jam processing cover 2 and the main body frame 15 of the image forming apparatus come into contact with each other and the jam processing cover 2 is closed, the jam processing ends. Cover 2
The jam processing cover 2 is securely closed by the magnetic force acting between the fixing device 217 and the fixing device 217.

In the present embodiment, the fulcrum of the jam processing cover 2 of the fixing device 217 is provided on the upper frame 10, but may be provided on the lower frame 11.

The jam-treating cover 2 is made of a heat-resistant resin (for example, PPE: polyphenylene ether) (trade name: Zylon (Asahi Kasei)), so that the jam-treating cover 2 also has a heat radiation preventing effect. be able to. This eliminates wasteful heat dissipation in the fixing device 217 and improves heat storage characteristics, thereby improving energy efficiency. It is not dangerous to directly touch the cover when performing the jam processing.

[0038]

According to the first aspect of the present invention, when performing the jam processing, the jam processing cover can be largely opened around the fulcrum provided at the end of the fixing unit main body on the inner side of the drawer, and the jam processing cover can be opened. Since it rotates in the horizontal plane, it does not close without its own weight or the like, and the user can easily perform the jam clearing operation. Further, since the jam processing cover is housed close to the apparatus main body, even if the fixing section is inserted into the apparatus main body without closing the jam processing cover after the jam processing, the cover is automatically brought into contact with the apparatus main body so as to come into contact with the apparatus main body. Closes. Thereby, it is possible to prevent the occurrence of the jam due to the forgetting to close the jam processing cover.

According to the second aspect of the present invention, when performing the jam processing, the pressing roller and the upper conveyance guide plate are simultaneously moved by opening the jam processing cover to separate the conveyance roller of the fixing unit main body from the lower conveyance guide. Therefore, the jammed paper can be easily recognized, and the jam clearing operation can be easily performed.

According to the third aspect of the present invention, after the jam processing,
When the fixing section is inserted into the apparatus main body without closing the cover, the jam processing cover is securely pushed into the fixing section by the contact between the apparatus main body and the holding guide, and the jam processing cover is securely closed. Such troubles do not occur.

According to the fourth aspect of the present invention, when the jam processing cover comes into contact with the apparatus main body and the jam processing cover is closed, if the jam processing cover is closed to a certain extent by the contact, the jam processing is finally finished. The jam cover is securely closed by the magnetic force acting between the cover and the fixing unit.

According to the fifth aspect of the present invention, the upper and lower fixing frames can be separated without removing the jam processing cover at the time of the operation such as the roller exchange, and the exchange operation can be performed in a short time.

According to the sixth aspect of the present invention, wasteful heat radiation is eliminated, heat storage characteristics are improved, and energy efficiency is improved. It is not dangerous to directly touch the cover when performing the jam processing.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing a configuration of a digital color copying machine 1 which is an image forming apparatus according to the present invention.

FIG. 2 is a cross-sectional view illustrating a configuration of a fixing device.

FIG. 3 is a perspective view illustrating a configuration of a fixing device and a jam clearing operation.

FIG. 4 is a perspective view showing a fulcrum portion of the jam processing cover.

FIG. 5 is an explanatory diagram illustrating a jam processing of a fixing device in a conventional image forming apparatus.

FIG. 6 is a cross-sectional view illustrating a configuration of a conventional fixing device.

[Explanation of symbols]

 2 Jam Handling Cover 3 Upper Conveying Guide Plate 4 Pressure Contact Roller 5 Support 8 Guide Rib 10 Upper Frame 11 Lower Frame 12 Rotating Support Shaft 15 Main Frame 16 Lower Conveying Guide Plate 17 Fixing Conveying Roller

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshiya Mikita 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (72) Inventor Atsushi Ide 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Osaka (72) Inventor Yoshinobu Tateishi 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka Prefecture F-term (reference) 2H033 AA37 BA03 BA06 BA10 3F049 AA04 DA12 DB03 LA04 LB03

Claims (6)

[Claims] When a paper jam occurs in a fixing unit for fixing an image by heating a sheet, the fixing unit is pulled out of a main body of the apparatus, and a jam release cover attached to the fixing unit main body is opened to open a paper jam. In the image forming apparatus performing the removal, the jam processing cover is provided so as to be openable in a horizontal plane around a fulcrum provided at an end of the fixing unit main body on the inner side of the drawer, and is disposed close to the apparatus main body. An image forming apparatus comprising: 2. The image according to claim 1, wherein the jam processing cover is provided with a pressing roller and an upper conveyance guide plate, and the fixing unit main body is provided with a conveyance roller and a lower conveyance guide. Forming equipment. 3. The image forming apparatus according to claim 1, wherein the jam processing cover is provided with a pressing guide on a side in contact with the apparatus main body and near an end on an open side. 4. The apparatus according to claim 1, wherein a magnet is provided on at least one of the jam processing cover and the fixing unit main body, a portion facing the magnet is a magnetic member, and the closed state of the jam processing cover is maintained by a magnetic force. The image forming apparatus according to claim 1. 5. The fixing unit main body is composed of two releasable frames, an upper frame and a lower frame, and a fulcrum of the jam processing cover is provided on one of the upper frame and the lower frame. The image forming apparatus according to claim 1, wherein: 6. The image forming apparatus according to claim 1, wherein a material of the jam processing cover is a heat-resistant resin.