JP2002072819A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily perform jam processing without breaking a jamming transfer material. SOLUTION: Since a holding member 33 holding a secondary transfer roller 12 and a fixing device 14 is mounted outside the image forming device so that it can be drawn out in a paper ejection direction, the secondary transfer roller 12 and fixing device 14 are exposed to outside the image forming device by drawing the holding member 33 out of the image forming device even if a jam occurs between the secondary transfer roller 12 and fixing device 14, so even if the secondary transfer roller 12 and fixing device 14 are put close to each other as a result of size reduction, the transfer material having jammed can easily be removed without being broken nor stained with unfixed toner inside nor outside the device.

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 such as a copying machine, a printer, a facsimile or the like which forms an image by an electrophotographic system or an electrostatic recording system, and more particularly to an image forming apparatus of an intermediate transfer system.

[0002]

2. Description of the Related 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 for each color, and a toner image of each color formed on each photosensitive drum is intermediately formed. 2. Description of the Related Art A so-called in-line type image forming apparatus for sequentially forming a color image by superimposing on a transfer member has been put to practical use.

FIG. 6 is a schematic diagram showing an example of a conventional full-color image forming apparatus (in the figure, a full-color copying machine) having an in-line type intermediate transfer member in an electrophotographic system.

This image forming apparatus comprises a printer section A and a reader section B. The printer section A includes an image forming section 1Y for forming a yellow image and an image forming section 1M for forming a magenta image. , An image forming unit 1C for forming a cyan image, and an image forming unit 1Bk for forming a black image. The four image forming units 1Y, 1M, 1
C and 1Bk are arranged in a line at regular intervals.

In each of the image forming sections 1Y, 1M, 1C, and 1Bk, a drum-type electrophotographic photosensitive member (hereinafter, referred to as a photosensitive drum) 2a, 2b, 2c, 2d as an image carrier is provided.
Is installed. Each photosensitive drum 2a, 2b, 2c, 2
around the charging device 3a, 3b, 3c, 3d, the developing devices 4a, 4b, 4c, 4d, the transfer blades 5a, 5b,
5c, 5d, drum cleaning devices 6a, 6b, 6
c, 6d are installed respectively, and the chargers 3a, 3d
Exposure devices 7a, 7b, 7c, 7d are installed above b, 3c, 3d and developing devices 4a, 4b, 4c, 4d, respectively. The developing devices 4a, 4b, 4c, and 4d store yellow toner, magenta toner, cyan toner, and black toner, respectively.

Each of the photosensitive drums 2a, 2b, 2c, 2d
A negatively charged OPC photoconductor has a photoconductive layer on a drum substrate made of aluminum, and is driven to rotate at a predetermined process speed in a direction indicated by an arrow (counterclockwise) by a driving device (not shown).

Chargers 3a, 3b, 3 as charging means
Reference numerals c and 3d denote photosensitive drums 2a, 2b, and 2 by charging bias applied from a charging bias power supply (not shown).
The surfaces c and 2d are uniformly charged to a predetermined negative potential.

[0008] The developing devices 4a, 4b, 4c, and 4d apply toner of each color to the electrostatic latent images formed on the photosensitive drums 2a, 2b, 2c, and 2d, respectively, and develop them as toner images (visible images). ). Developing devices 4a, 4b, 4c, 4
As a developing method using d, for example, a mixture of toner particles and a magnetic carrier is used as a developer and conveyed by magnetic force, and the photosensitive drums 2a, 2b, 2c,
A two-component contact development method of developing in contact with d can be used.

Transfer blades 5a and 5 as transfer means
b, 5c, and 5d are formed of elastic members, and each photosensitive member passes through an endless belt-shaped intermediate transfer member (hereinafter, referred to as an intermediate transfer belt) 8 at each of the primary transfer nip portions Ta, Tb, Tc, and Td. They are in contact with the drums 2a, 2b, 2c, 2d.
The intermediate transfer belt 8 is stretched between the driving roller 9, the secondary transfer opposing roller 10, and the tension roller 11, and is rotated (moved) in the direction of the arrow (clockwise) by the driving of the driving roller 9. The intermediate transfer belt 8 is made of a dielectric resin such as polycarbonate, polyethylene terephthalate resin film, polyvinylidene fluoride resin film and the like.

The secondary transfer facing roller 10 contacts the secondary transfer roller 12 via the intermediate transfer belt 8 to form a secondary transfer portion Te. The secondary transfer roller 12 is provided so as to be able to freely 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 the transfer residual toner remaining on the surface of the intermediate transfer belt 8 is provided. In the belt cleaning device 13, a plate-like blade member 13 a made of an elastic member is provided in contact with the intermediate transfer belt 8. Further, a fixing device 14 having a fixing roller 14a and a pressure roller 14b is provided downstream of the secondary transfer section in the transfer material transport direction.

The drum cleaning devices 6a, 6b, 6
c and 6d are photosensitive drums 2a and 2d by blade members.
Transfer residual toner remaining on the surfaces b, 2c and 2d is removed and collected.

Exposure devices 7a, 7b, 7c and 7d output laser light modulated corresponding to time-series electric digital pixel signals of image information input from reader unit B from a laser output unit (not shown). Each of the photosensitive drums 2a and 2 is rotated via a polygon mirror (not shown) which rotates at a high speed.
By exposing the surfaces b, 2c and 2d, each charger 3
a, 3b, 3c, 3d, each of the photosensitive drums 2a,
An electrostatic latent image of each color is formed on the surface of 2b, 2c, 2d according to the image information.

The reader section B has a scanning section 20 for irradiating an image of a document (not shown) with light to scan the same.
Scanning light (reflected light from the original) from the optical lens system 21
Is input to the CCD 22 via the
Each exposure device 7 of the printer unit A is subjected to a process such as color separation.
a, 7b, 7c and 7d.

Next, an image forming operation by the above-described image forming apparatus will be described.

When an image formation start signal is issued, each of the image forming units 1Y, 1Y, which is rotationally driven at a predetermined process speed, is driven.
1M, 1C, 1Bk photosensitive drums 2a, 2b, 2c,
2d is uniformly negatively charged by the chargers 3a, 3b, 3c, 3d, respectively. Then, the exposure devices 7a,
Reference numerals 7b, 7c, and 7d convert image signals obtained by color separation of a document (not shown) input from the reader unit B into optical signals at a laser output unit (not shown), and use the converted optical signals. Each photosensitive drum 2a charged with a certain laser beam,
Scanning exposure is performed on each of 2b, 2c, and 2d to form an electrostatic latent image.

First, yellow toner is caused to adhere 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. Then, the image is visualized as a toner image. The yellow toner image is rotated (moved) by the transfer blade 5a to which a primary transfer bias (a polarity opposite to that of the toner (positive polarity)) is applied at a primary transfer portion Ta between the photosensitive drum 2a and the transfer blade 5a. The primary transfer is performed on the intermediate transfer belt 8.

The intermediate transfer belt 8 to which the yellow toner image has been transferred is rotated (moved) toward the image forming section 1M. In the image forming section 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
The image is transferred at the primary transfer portion Tb.

Hereinafter, the cyan and black toner images formed by the photosensitive drums 2c and 2d of the image forming units 1C and 1Bk are formed on the yellow and magenta toner images superimposed and transferred on the intermediate transfer belt 8 in the same manner. Each primary transfer section Tc, T
A full color toner image is formed on the intermediate transfer belt 8 by superimposing sequentially at d.

Then, the sheet cassettes 15a, 15a, 15a, and 15b are moved in synchronization with the timing at which the leading end of the full-color toner image on the intermediate transfer belt 8 is moved to the secondary transfer section Te between the secondary transfer opposing roller 10 and the secondary transfer roller 12. The transfer material (paper) P selected from 15b or the manual feed 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 moved via the intermediate transfer belt 8 to the secondary transfer opposing roller 1.
Contact 0. Then, a full-color toner image is collectively formed on the transfer material P conveyed to the secondary transfer portion Te by the secondary transfer roller 12 to which a secondary transfer bias (a polarity opposite to the toner (positive polarity)) is applied. Transcribed.

The transfer material P on which the full-color toner image is formed is conveyed to the fixing device 14, where the full-color toner image is heated and pressed at the fixing nip between the fixing roller 14a and the pressure roller 14b, and the surface of the transfer material P is pressed. Then, the sheet is discharged onto the sheet discharge tray 19, and a series of image forming operations is completed.

At the time of the primary transfer described above, the primary transfer residual toner remaining on each of the photosensitive drums 2a, 2b, 2c and 2d is removed from each of the drum cleaning devices 6a, 6b and 6.
They are removed and recovered by c and 6d, respectively. The secondary transfer residual toner 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.

When a monochromatic image (for example, a monochrome image) is obtained, a specific image forming unit (for example, the image forming unit 1B) is used.
k), a single-color (monochrome image) visible image is primarily transferred onto the intermediate transfer belt 8, and a single-color image can be obtained through a process similar to the above-described case of forming a full-color image.

[0023]

In the image forming apparatus of the intermediate transfer system, the transfer material transporting section 17 is formed by using the endless belt-like intermediate transfer belt 8 as the intermediate transfer member as in the above-described image forming apparatus. , Secondary transfer unit T
e. The degree of freedom in the arrangement of the fixing device 14 and the like is created. Therefore, the transfer material transport path from the transfer material transport unit 17 to the fixing device 14 through the secondary transfer unit Te can be shortened, which is advantageous for miniaturization of the apparatus.

However, since the transfer material transport section 17, the secondary transfer section Te, the fixing device 14 and the like are arranged close to each other due to the miniaturization of the apparatus, when the transfer material P becomes jammed (paper jam). The following problems arise.

That is, when the occurrence of a paper jam (jam) during image formation is detected by sensors (not shown) provided at various portions of the transfer material conveying path, the image forming apparatus stops the image forming operation. Then, a message is displayed on a display panel (not shown) to notify the user that the user is to clear the paper jam. At this time, the transfer material left in the apparatus is often held in a plurality of places such as the secondary transfer portion Te and the fixing device 14 because the transfer material transport path is short.

Therefore, the user needs to remove the transfer material that has caused a paper jam in the transfer material transport path in the apparatus or the transfer material that has been left in the apparatus because the image forming operation has been stopped due to the occurrence of the paper jam. was there. At this time, in particular, the fixing device 1
When the sheet is jammed and the image forming operation is stopped when the secondary transfer portion Te and the secondary transfer portion Te are close to each other, the transfer material is transferred to the secondary transfer portion T.
e and the fixing device 14 in many cases.

As a result, when the fixing device 14 is pulled out of the apparatus in order to perform a paper jam process, the transfer material that is 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, so that the paper jam transfer material is torn between the secondary transfer portion Te and the paper jam transfer material. Then, the inside and outside of the apparatus are stained by the unfixed toner.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of easily performing a jam processing without damaging a jammed transfer material with a simple configuration.

[0029]

In order to achieve the above object, a toner image formed on one or a plurality of image carriers is primarily transferred to an intermediate transfer body in a primary transfer section, and the intermediate transfer is performed. The toner image on the body is secondarily transferred to a transfer material at a secondary transfer portion by a secondary transfer member abutting on the intermediate transfer member, and the secondary transferred toner image is fixed on the transfer material by fixing means. In the image forming apparatus, at least the secondary transfer member and the fixing unit are held by a common holding member, and the holding member is attached to the image forming apparatus so that the holding member can be pulled out in the sheet discharging direction. It is characterized by having.

Further, the holding member can be drawn out of the image forming apparatus and in the sheet discharging direction along a guide rail movable in a substantially horizontal direction.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments.

<First Embodiment> FIG. 1 is a schematic configuration diagram showing an image forming apparatus (an in-line type full-color copying machine of an electrophotographic type in the figure) according to a first embodiment of the present invention. The same members as those of the image forming apparatus of the conventional example shown in FIG. 6 are denoted by the same reference numerals, and overlapping description will be omitted. Also in the present embodiment, an image forming operation is performed in the same manner as in the above-described conventional image forming apparatus. In the present embodiment, the description of the image forming operation is omitted.

In the present image forming apparatus, each of the exposure devices 7a, 7
The laser light modulated corresponding to the time-series digital pixel signals of the image information output from the b, 7c and 7d passes through the respective reflecting mirrors 7e, 7f, 7g and 7h, respectively, and the respective photosensitive drums 2a, 2b and 2c. , 2d to form an electrostatic latent image.

A pre-secondary transfer guide 30a for guiding the transfer material P to the secondary transfer portion Te is provided upstream of the secondary transfer portion Te in the transfer material transport direction, and a transfer of the secondary transfer portion Te is performed. The transfer material P on which the toner image has been transferred is located on the downstream side in the material transport direction.
A fixing pre-fixing guide 30b for guiding the toner to the fixing device 14 is provided.

In the image forming apparatus according to the present embodiment, as shown in FIGS. 2 and 3 (viewed in the direction of arrow A in FIG. 1), a guide 30a before the secondary transfer and a guide 30b before the fixing are provided.
Are formed integrally with each other via a concave member 30c, and the secondary transfer roller 12 located in the concave member 30c is applied with an appropriate pressure (5880-15) by each roller pressing spring 31.
680 mN is desirable), and comes into contact with the secondary transfer opposing roller 10 via the intermediate transfer belt 8, and is driven to rotate by the frictional force with the intermediate transfer belt 8. Further, the secondary transfer roller 12 of the present embodiment has a diameter of 1 mm using an aluminum pipe or the like.
It is a metal roller of 6 to 30 mm. Note that the secondary transfer roller 12 may be an elastic roller such as urethane rubber.

The secondary transfer opposing roller 10 and each roller pressing spring 31 are held in a concave member 30c, and each roller pressing spring 31 is connected to the concave member 30c and the secondary transfer roller 12c.
It is arrange | positioned between each bearing 12a of both ends. Further, in the present embodiment, the secondary transfer bias to the secondary transfer roller 12 is configured to be applied from the secondary transfer opposing roller 10, and the secondary transfer roller 12 is electrically grounded. The effect of the present invention can be obtained even when the secondary transfer bias is applied to the secondary transfer roller 12 and the secondary transfer opposing roller 10 is electrically grounded. Also, 2
The secondary transfer roller 12 may be rotationally driven by a pulse motor or the like in consideration of the transportability of the transfer material P in the next transfer unit Te.

Both sides of the lower surface of the pre-fixing guide 30b on the side of the fixing device 14 are rotatably held by holding members 33 by respective rotating shafts 32. Each pressing spring 34 is disposed on both sides between the pre-fixing guide 30b and the holding member 33, and the pre-fixing guide 30b is moved by the spring force of the pressing spring 34 (preferably 19.6 to 29.4N). By the urging, the secondary transfer roller 12 is brought into contact with the secondary transfer opposing roller 10 via the intermediate transfer belt 8 at the above-described appropriate pressure. The holding member 33 includes the fixing device 14 and the discharge tray 1.
9 is also fixed and held.

As shown in FIG. 3 (a view as seen from the direction of arrow A in FIG. 1), the holding member 33 has rail members 3 on both sides thereof.
6 are fixed to each other, and each rail member 36 is movably mounted in each rail support member 37 which is directly fixed horizontally to the inner wall of the front plate 38 and the rear plate 39 of the printer unit A in the horizontal direction. Accordingly, the holding member 33, together with the secondary transfer roller 12, the fixing device 14, the paper discharge tray 19, the secondary pre-transfer guide 30a, and the pre-fixation guide 30b, which are held outside the printer unit A and in the paper discharge direction ( It is movable in the direction of arrow B in FIG.

A grip 35 is formed on the holding member 33. The user can easily pull out the holding member 33 by gripping and pulling the grip 35.

Next, a description will be given of a treatment in this embodiment when a paper jam (jam) occurs during image formation.

As shown in FIG. 4, a paper jam occurs in a state where the transfer material (paper) P is sandwiched by both the secondary transfer portion Te and the fixing device 14 during the image forming operation, and the image forming operation is performed. Is stopped, an unfixed toner image is placed on the surface of the transfer material P.

When the apparatus is stopped, the transfer material P is also held between the pair of registration rollers 18 located upstream of the secondary transfer portion Te in the sheet passing direction (in the present embodiment, the transfer material P
Is not held between the pair of registration rollers 18).
For example, if the sensor is recognized by sensors (not shown) arranged at various places in the paper feed path, a registration on the display panel (not shown) of the apparatus is performed before prompting the user to perform a paper jam process. It is desirable that the transfer material P held by rotation of the roller pair 18 be transported downstream in the sheet passing direction until the holding is released. Alternatively, it is desirable that when the user pulls out the holding member 33 due to the registration roller pair 18 being separated from each other, the transfer material P can also be reliably drawn out.

Then, when such a paper jam (jam) occurs, a message is displayed on a display panel (not shown) or the like to notify the user to perform the work for clearing the paper jam.

Then, as shown in FIG. 5, the user holds the handle 35 of the holding member 33 and discharges the paper (in the direction of arrow B).
To the rail members 36 on both sides of the holding member 33.
Is guided by each rail support member 37, and the holding member 33
And the pre-secondary transfer guide 30 held by the holding member
a, the secondary transfer roller 12, the pre-fixing guide 30b, the fixing device 14, and the paper jammed transfer material P are pulled out of the printer unit A.

In this way, the paper 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). Even when the transfer roller 12 and the fixing device 14 are close to each other, the transfer material P
Can be prevented from being damaged by tearing, and the unfixed toner image on the paper jammed transfer material P can be prevented from being scattered in and out of the printer unit A, so that the paper jam can be easily and quickly processed. Can do it. Further, by pulling out the paper in the sheet discharging 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.

In addition, the holding member 33 is pulled out of the printer unit A other than during the above-described paper jam processing, so that maintenance and replacement of the secondary transfer roller 12 and the fixing device 14 on the holding member 33 can be easily performed. Can do it.

[0047]

As described above, according to the present invention, the holding member holding at least the secondary transfer member and the fixing means is attached to the image forming apparatus so as to be able to be pulled out to the outside and in the sheet discharging direction. Therefore, even if a jam occurs near the secondary transfer member or the fixing unit or between the secondary transfer member and the fixing unit, the secondary transfer is performed by pulling the holding member out of the image forming apparatus and in the sheet discharging direction. Since the member and the fixing unit are exposed to the outside of the image forming apparatus, even if the secondary transfer member and the fixing unit are close to each other due to miniaturization, the jammed transfer material is not damaged and the inside and outside of the apparatus are not damaged. Can be easily removed without contaminating with unfixed toner.

Further, by pulling out the holding member to the outside of the image forming apparatus, the secondary transfer member and the fixing means 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 showing 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 unit of the image forming apparatus according to the embodiment of the present invention.

FIG. 3 is a schematic diagram viewed from the direction of arrow A in FIG. 2;

FIG. 4 is a diagram illustrating a state in which a paper jam has occurred between a fixing device and a secondary transfer unit.

FIG. 5 is a diagram illustrating a state during a paper jam process 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 unit 2a, 2b, 2c, 2d Photosensitive drum (image carrier) 3a, 3b, 3c, 3d Charger 4a, 4b, 4c, 4d Developing device 5a, 5b, 5c, 5d Transfer Blades 6a, 6b, 6c, 6d Drum cleaning device 7a, 7b, 7c, 7d Exposure device 8 Intermediate transfer belt (intermediate transfer member) 12 Secondary transfer roller (secondary transfer member) 13 Belt cleaning device 14 Fixing device (fixing means) 30a Guide before secondary transfer 30b Guide before fixing 31 Roller pressure spring 33 Holding member 34 Pressure spring 36 Rail member 37 Rail support member 38 Front plate 39 Rear plate

Claims (2)

[Claims] 1. A toner image formed on one or a plurality of image carriers is primarily transferred to an intermediate transfer body at a primary transfer section, and the toner image on the intermediate transfer body is applied to the intermediate transfer body. An image forming apparatus, in which a secondary transfer member is secondarily transferred to a transfer material at a secondary transfer portion by a contacting secondary transfer member, and the secondary-transferred toner image is fixed on the transfer material by a fixing unit, at least the secondary transfer member And the fixing unit are held by a common holding member, and the holding member is mounted outside the image forming apparatus so as to be able to be pulled out in the sheet discharging direction. 2. The image forming apparatus according to claim 1, wherein the holding member can be drawn out of the image forming apparatus and in a sheet discharging direction along a guide rail movable in a substantially horizontal direction. apparatus.