JP2000293074A - Double-sided image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform jamming processing without soiling hands or the inside of a device by unfixed toner on an intermediate transfer body by stopping the intermediate transfer body after cleaning it even when trouble that transfer material is not supplied is caused. SOLUTION: When the trouble that recording paper P is not supplied to an intermediate transfer belt 14a is caused at the time of double-sided image forming or at the time of rear-side image forming, the formation of a toner image being a rear-side image on a photoreceptor drum 10 and the transfer of the toner image being the rear-side image to the belt 14a by a primary transfer device 14c are instantaneously stopped. Simultaneously, an intermediate transfer body cleaning blade 251 of an intermediate transfer body cleaning device 250 which is set in an abutting released state is set in the abutting state so as to start the cleaning of the belt 14a. After the surface of the cleaned belt 14a passes through a position on the belt 14a side surface side of a fixing device 17 influenced by heat from the device 17, desirably, after all the surface of the belt 14a is cleaned, the movement of the belt 14a is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to copying in which a charging means, an image writing means and a developing means are arranged around an image carrier to transfer and fix a toner image formed on the image carrier onto a transfer material. The present invention relates to an electrophotographic double-sided image forming apparatus such as a machine, a printer, and a facsimile.

[0002]

2. Description of the Related Art Conventionally, in forming a double-sided image, an image on one side formed on an image carrier is transferred and fixed onto a transfer material, and this is temporarily stored in a double-sided reversal feeding device, and the image is re-supported. A method has been adopted in which a transfer material is fed from a two-sided reversing feed device in synchronization with an image formed on a body, and an image on the other surface is transferred and fixed onto the transfer material.

As described above, in the double-sided image forming apparatus, as described above, the transfer of the transfer material such as feeding to the double-sided reverse feeding device and passing through the fixing device twice is performed. This is a cause of causing jams and wrinkles of the transfer material.

On the other hand, JP-B-49-37538 and JP-B-54-28740, and JP-A-1-44457.
Japanese Patent Application Laid-Open Nos. 4-214576 and 4-214576 propose a method in which a toner image is formed on both surfaces of a transfer material using an image carrier and an intermediate transfer member, and then fixed once.

Further, the present inventors have arranged a plurality of sets of toner image forming means including a charging means, an image writing means, a developing means, etc. around a photosensitive drum (image carrier), and provided on the photosensitive drum. Once the formed superimposed color toner image is once transferred onto the belt-shaped intermediate transfer member, a superimposed color toner image is formed again on the photoconductor drum, and the toner image on the photoconductor drum and the intermediate transfer member are formed. The toner image on the photosensitive drum is transferred to both sides of the transfer material conveyed by the intermediate transfer member at the same time as the toner image of the intermediate transfer member, and the toner image on the intermediate transfer member is transferred to the back surface. Japanese Patent Application Laid-Open No. 9-258 discloses an image forming apparatus and an image forming method for separating a transfer material from an intermediate transfer body, fixing a toner image on the transfer material and forming a double-sided color image after transferring the image.
No. 492 and JP-A-9-258516.

[0006]

In the conventional double-sided image forming apparatus, when a paper-feed jam occurs, the machine is immediately stopped, and thus has the following problems. That is, in a one-pass double-sided image forming apparatus that forms an image on both sides of a transfer material using the belt-shaped intermediate transfer body (intermediate transfer belt) as described above, the intermediate image is temporarily formed during double-sided image formation or back-side image formation. In order to transfer the toner image onto the transfer member and supply the transfer material onto the toner image on the intermediate transfer member, a paper jam in a sheet cassette, which is a transfer material storage unit, or a transfer material feeding unit. When an accident such as a feeding jam at a certain timing roller occurs, the machine stops with a toner image formed on the intermediate transfer member. For this reason, if the user clears the machine without performing the jam processing and the jam processing operation is prolonged, or if the user does not copy (print) the paper after the jam processing, the portion of the intermediate transfer member facing the fixing unit is not printed. The remaining toner image is fused to the intermediate transfer member due to the influence of heat from the fixing unit and cannot be cleaned, so that in the copy (print) after the jam processing, the back surface of the transfer material becomes dirty, or the toner image is removed. A problem arises in that a good image cannot be obtained due to the influence of transfer.

[0007] The present invention solves the above-mentioned problems, and even if an accident occurs in which the transfer material is not supplied to the intermediate transfer member during double-sided image formation or back-side image formation, the intermediate transfer member facing the fixing means can be used. To prevent the toner image remaining on the intermediate transfer body from being fused by the influence of heat of the fixing unit,
A first object is to provide a double-sided image forming apparatus capable of obtaining a good image.

Further, in the conventional double-sided image forming apparatus, the machine is immediately stopped even when a so-called drum wrap jam occurs in which the transfer material is not adsorbed on the image carrier and is not normally conveyed. There was a problem. That is, in the double-sided image forming apparatus, when forming a double-sided image or a rear-side image, a toner image is temporarily transferred onto the intermediate transfer body, and is transferred onto the intermediate transfer body in synchronization with the toner image on the intermediate transfer body. The transfer material is supplied. When the front surface toner image is transferred (when the back surface image is formed, the front surface toner image is not transferred, so the transfer material passes through the position where the image carrier and the intermediate transfer body face each other). If the transfer material is poorly adsorbed to the intermediate transfer member and the transfer material is not adsorbed to the image carrier and is not conveyed normally, and an accident such as a jam around the drum occurs, the intermediate transfer is performed. The machine will stop with the toner image formed on the body. For this reason, if the user clears the machine without performing the jam processing and the jam processing operation is prolonged, or if the user does not copy (print) the paper after the jam processing, the portion of the intermediate transfer member facing the fixing unit is not printed. The remaining toner image is fused to the intermediate transfer member due to the influence of heat from the fixing unit and cannot be cleaned, so that the copy (print) after the jam processing is performed.
In this case, there arises a problem that a good image cannot be obtained because the back surface of the transfer material becomes dirty or the transfer of the toner image is affected.

The present invention solves the above-mentioned problems, so that even when an accident occurs in which a transfer material is adsorbed on an image carrier and is not conveyed normally during double-sided image formation or back-side image formation, the transfer member faces the fixing means. A second object of the present invention is to provide a double-sided image forming apparatus capable of obtaining a good image by preventing a toner image remaining on a part of the intermediate transfer member from being fused to the intermediate transfer member due to the influence of heat of the fixing unit. Aim.

Further, in the conventional double-sided image forming apparatus, the machine is immediately stopped even when a transfer material conveyance jam occurs between the timing roller position and the transfer material separation position from the intermediate transfer member. Therefore, there were the following problems. That is, in the double-sided image forming apparatus, when forming a double-sided image or a rear-side image, a toner image is temporarily transferred onto an intermediate transfer body, and a transfer material feeding unit is synchronized with the toner image on the intermediate transfer body. The transfer material is supplied onto the intermediate transfer body by the timing roller, but if an accident such as a jam of the transfer material from the timing roller position to the separation position of the transfer material from the intermediate transfer body occurs, Therefore, the machine stops in a state where the toner image is formed on the intermediate transfer member. For this reason, when the user leaves the machine without clearing the jam, the jam clearing operation is prolonged.
Otherwise, the toner image remaining on the intermediate transfer member in the portion facing the fixing means is fused to the intermediate transfer member due to the influence of heat and cannot be cleaned, and in the copy (print) after the jam processing, A problem arises in that a good image cannot be obtained because the back surface of the transfer material becomes dirty or the transfer of the toner image is affected.

[0011] The present invention solves the above-mentioned problems, and even when an accident occurs in which transfer of a transfer material by an intermediate transfer member is not performed normally during double-sided image formation or backside image formation,
Provided is a double-sided image forming apparatus capable of obtaining a good image by preventing a toner image remaining on a portion of an intermediate transfer member facing a fixing unit from being fused to an intermediate transfer member due to heat of the fixing unit. This is the third object.

Further, in the conventional double-sided image forming apparatus,
After the toner image is transferred to both surfaces of the transfer material, the toner images on the transfer material are simultaneously fixed on both surfaces. That is, in the double-sided image forming apparatus, at the time of forming a double-sided image, a toner image is temporarily transferred onto an intermediate transfer body, and is synchronized with the toner image on the intermediate transfer body by a timing roller as a transfer material feeding unit. The transfer material is supplied onto the intermediate transfer body. When an accident such as a so-called transfer material conveyance jam that is not conveyed occurs, an unfixed toner image exists on both surfaces of the transfer material, or a toner image exists on the surface of the transfer material and on the intermediate transfer body. In such a case, a problem occurs in that the hands and the inside of the aircraft get dirty.

[0013] The present invention solves the above-mentioned problems, and even if an accident occurs in which the transfer material is not normally conveyed by the intermediate transfer member during double-sided image formation, the unfixed toner on the intermediate transfer member causes the transfer. It is a fourth object of the present invention to provide a double-sided image forming apparatus capable of performing jam processing without soiling the hands and the inside of the apparatus.

[0014]

A first object of the present invention is to provide an image bearing member for carrying a toner image formed by a toner image forming means on a surface thereof, and transferring and transferring the toner image on the image bearing member. A belt-shaped intermediate transfer member that supports the toner image on the surface thereof and supports and conveys the transfer material; a transfer material supply unit that supplies the transfer material to the intermediate transfer member; and a toner image on the image carrier. Primary transfer means for transferring the toner image onto the intermediate transfer body or the surface of the transfer material, secondary transfer means for retransferring the toner image on the intermediate transfer body to the back surface of the transfer material, and toner on the transfer material In a double-sided image forming apparatus having a fixing unit for fixing an image and an intermediate transfer body cleaning unit for cleaning the intermediate transfer body, when forming a double-sided image for forming images on both sides of the transfer material, or only for the back surface of the transfer material Painting At the rear surface image formation to form an, if an accident where the transfer material is not supplied to the intermediate transfer member occurs, forming a toner image by the toner image forming means,
And immediately stopping the transfer of the toner image by the primary transfer unit, starting the cleaning of the intermediate transfer body by the intermediate transfer body cleaning unit, and at least cleaning the intermediate transfer body by the intermediate transfer body cleaning unit. A double-sided image forming apparatus (1) wherein the movement of the intermediate transfer body is stopped after a surface of the body passes a position of the fixing unit on the side of the intermediate transfer body.
Invention), and a first image carrier for carrying on its surface the toner image formed by the first toner image forming means, and carrying a toner image formed by the second toner image forming means on its surface. A second image carrier, a belt-shaped intermediate transfer body onto which the toner image on the first image carrier is transferred, the transferred toner image is supported on the surface, and a transfer material is supported and transported; Transfer material supply means for supplying the transfer material to the intermediate transfer member, first primary transfer means for transferring a toner image on the first image carrier to the intermediate transfer member, and second transfer member
A second primary transfer means for transferring the toner image on the image carrier to the surface of the transfer material, a secondary transfer means for retransferring the toner image on the intermediate transfer body to the back surface of the transfer material, In a double-sided image forming apparatus having a fixing unit for fixing a toner image on the transfer material and an intermediate transfer body cleaning unit for cleaning the intermediate transfer body, when forming a double-sided image for forming an image on both sides of the transfer material, When an accident occurs in which the transfer material is not supplied to the intermediate transfer body at the time of forming a back image in which an image is formed only on the back surface of the transfer material, a toner image is formed by the first and second toner image forming units. And immediately stopping the transfer of the toner image by the first and second primary transfer means,
At least, the movement of the intermediate transfer member is stopped after the surface of the intermediate transfer member cleaned by the intermediate transfer member cleaning unit has passed the position of the fixing unit on the side surface of the intermediate transfer member. This is achieved by a double-sided image forming apparatus (second invention).

A second object of the present invention is to provide an image bearing member for carrying a toner image formed on a surface thereof by a toner image forming means, a toner image on the image bearing member being transferred, and transferring the transferred toner image. A belt-like intermediate transfer body that supports and transports a transfer material, a transfer material supply unit that supplies the transfer material to the intermediate transfer body, and transfers the toner image on the image carrier to the intermediate transfer body. Primary transfer means for transferring the toner image on the body or the surface of the transfer material, secondary transfer means for retransferring the toner image on the intermediate transfer body to the back surface of the transfer material, and fixing the toner image on the transfer material In a double-sided image forming apparatus having a fixing unit and an intermediate transfer body cleaning unit for cleaning the intermediate transfer body, an image is formed at the time of double-sided image formation where images are formed on both sides of the transfer material or only on the back surface of the transfer material. You When an accident occurs in which the transfer material adheres to the image carrier and is not conveyed normally during backside image formation, movement of the image carrier, formation of a toner image by the toner image forming unit, and primary transfer unit The transfer of the toner image by the secondary transfer means, the supply of the transfer material by the transfer material supply means, and the cleaning of the intermediate transfer body by the intermediate transfer body cleaning means. Starting, and stopping the movement of the intermediate transfer body after at least the surface of the intermediate transfer body cleaned by the intermediate transfer body cleaning unit has passed the position of the fixing unit on the side surface of the intermediate transfer body. Characteristic double-sided image forming apparatus (third
Invention), and a first image carrier for carrying on its surface the toner image formed by the first toner image forming means, and carrying a toner image formed by the second toner image forming means on its surface. A second image carrier, a belt-shaped intermediate transfer body onto which the toner image on the first image carrier is transferred, the transferred toner image is supported on the surface, and a transfer material is supported and transported; Transfer material supply means for supplying the transfer material to the intermediate transfer member, first primary transfer means for transferring a toner image on the first image carrier to the intermediate transfer member, and second transfer member
A second primary transfer means for transferring the toner image on the image carrier to the surface of the transfer material, a secondary transfer means for retransferring the toner image on the intermediate transfer body to the back surface of the transfer material, In a double-sided image forming apparatus having a fixing unit for fixing a toner image on the transfer material and an intermediate transfer body cleaning unit for cleaning the intermediate transfer body, when forming a double-sided image for forming an image on both sides of the transfer material, When an accident occurs in which the transfer material is adsorbed on the second image carrier and is not conveyed normally during backside image formation in which an image is formed only on the backside of the transfer material, the first and second images are formed. Movement of the carrier, formation of a toner image by the first and second toner image forming means, transfer of the toner image by the first and second primary transfer means, and transfer of the toner image by the secondary transfer means Transcription To stop immediately the supply of the transfer material by said transfer material feeding means to beauty, at least,
A double-sided image wherein the movement of the intermediate transfer body is stopped after a surface of the intermediate transfer body cleaned by the intermediate transfer body cleaning unit passes a position of the fixing unit on a side surface of the intermediate transfer body. This is achieved by a forming apparatus (a fourth invention).

A third object of the present invention is to provide an image carrier for carrying a toner image formed by a toner image forming means, a toner image on the image carrier being transferred, and carrying the transferred toner image. A belt-shaped intermediate transfer member that supports and conveys a transfer material; a primary transfer unit that transfers a toner image on the image carrier to the surface of the intermediate transfer member or the transfer material; Double-sided image having a secondary transfer means for re-transferring the toner image on the back surface of the transfer material, a fixing means for fixing the toner image on the transfer material, and an intermediate transfer body cleaning means for cleaning the intermediate transfer body In the forming apparatus, the transfer of the transfer material by the intermediate transfer member is performed normally during the double-sided image formation in which an image is formed on both sides of the transfer material or the back surface image in which the image is formed only on the back surface of the transfer material. If an accident occurs, the image carrier is driven, the intermediate transfer member is driven, a toner image is formed by the toner image forming unit, and a toner image is transferred by the primary transfer unit and the secondary transfer unit. Is stopped immediately, and a manual operation for discharging the transfer material that has not been normally conveyed to the outside of the double-sided image forming apparatus is enabled, and after the transfer material is discharged out of the double-sided image forming apparatus by the manual operation. A double-sided image forming apparatus (fifth invention), wherein the intermediate transfer body and the intermediate transfer body cleaning means are driven for a predetermined time to clean the intermediate transfer body, and a first toner image forming means A first image carrier that carries the toner image formed by
A second image carrier that carries the toner image formed by the second toner image forming means, and a toner image on the first image carrier that is transferred and carries the transferred toner image; A belt-shaped intermediate transfer body that supports and transports the transfer material,
A first primary transfer unit for transferring the toner image on the first image carrier to the intermediate transfer body, and a second primary transfer unit for transferring the toner image on the second image carrier to the surface of the transfer material Primary transfer means, secondary transfer means for retransferring the toner image on the intermediate transfer member to the back surface of the transfer material, fixing means for fixing the toner image on the transfer material, and A double-sided image forming apparatus having an intermediate transfer body cleaning means for cleaning, wherein the intermediate transfer is performed during double-sided image formation in which images are formed on both sides of the transfer material or during backside image formation in which an image is formed only on the backside of the transfer material. When an accident occurs in which the transfer of the transfer material by the body is not performed normally, the driving of the first and second image carriers, the driving of the intermediate transfer body, and the first and second toner images Of the toner image by the forming means The transfer of the toner image by the first and second primary transfer means and the retransfer of the toner image by the secondary transfer means are immediately stopped, and the transfer material that has not been normally conveyed is removed. A manual operation for discharging the sheet to the outside of the double-sided image forming apparatus is enabled, and after the transfer material is discharged to the outside of the double-sided image forming apparatus by the manual operation, the intermediate transfer body and the intermediate transfer body cleaning unit are driven for a predetermined time. This is achieved by a double-sided image forming apparatus (sixth invention) that cleans the intermediate transfer member.

A fourth object of the present invention is to provide an image carrier for carrying a toner image formed by a toner image forming means, a toner image on the image carrier being transferred, and carrying the transferred toner image. A belt-shaped intermediate transfer member that supports and conveys a transfer material; a primary transfer unit that transfers a toner image on the image carrier to the surface of the intermediate transfer member or the transfer material; An image is formed on both sides of the transfer material in a double-sided image forming apparatus having a secondary transfer means for retransferring the toner image to the back surface of the transfer material and a fixing means for fixing the toner image on the transfer material. In this case, when an accident occurs in which the transfer of the transfer material by the intermediate transfer body is not performed normally, driving of the image carrier, driving of the intermediate transfer body, formation of a toner image by the toner image forming unit,
And performing a stop operation for immediately stopping the transfer of the toner image by the primary transfer unit and the secondary transfer unit. After the stop operation, the transfer material that has not been normally conveyed is
When the transfer of the transfer material by the intermediate transfer member is normally performed, a manual operation for returning to the transfer material transfer surface on the intermediate transfer member is enabled, and the transfer member transfers the transfer material on the intermediate transfer member. After being returned to the transfer material transport surface, the image carrier,
Driving the intermediate transfer body and the fixing unit for a predetermined time,
A double-sided image forming apparatus (seventh invention), wherein the transfer material is discharged out of the double-sided image forming apparatus; and
A first image carrier for carrying the toner image formed by the first toner image forming means; a second image carrier for carrying the toner image formed by the second toner image forming means; The toner image on the first image carrier is transferred, and the belt-shaped intermediate transfer member that supports the transferred toner image and supports and conveys the transfer material, and the toner image on the first image carrier is A first primary transfer unit for transferring the toner image on the intermediate transfer body, a second primary transfer unit for transferring a toner image on the second image carrier to a surface of the transfer material, An image is formed on both sides of the transfer material in a double-sided image forming apparatus having a secondary transfer means for retransferring the toner image to the back surface of the transfer material and a fixing means for fixing the toner image on the transfer material. In this case, the transfer of the transfer material by the intermediate transfer body is performed normally. If there is no accident, the first and second image carriers are driven, the intermediate transfer member is driven, toner images are formed by the first and second toner image forming units, and the first and second toner images are formed. A stop operation for immediately stopping the transfer of the toner image by the second primary transfer unit and the retransfer of the toner image by the secondary transfer unit is performed. After the stop operation, the transfer that is not normally conveyed A manual operation of returning the transfer material to the transfer material transfer surface on the intermediate transfer member when the transfer material has been normally transferred by the intermediate transfer member. After being returned to the transfer material transport surface on the body, the second
The image carrier, the intermediate transfer member, and the fixing unit are driven for a predetermined time, and the transfer material is discharged out of the double-sided image forming apparatus. You.

[0018]

Embodiments of the present invention will be described below. Note that the description in this column does not limit the technical scope of the claims and the meaning of terms. Also, the following assertive description in the embodiment of the present invention indicates the best mode, and does not limit the meaning of the terms of the present invention or the technical scope. Also, the following assertive description in the embodiment of the present invention indicates the best mode, and does not limit the meaning of the terms of the present invention or the technical scope. In the following description of the embodiment, the surface of the transfer material supported and conveyed by the intermediate transfer member, the surface on the side facing the image carrier is the front surface, and the other surface, that is, the surface on the side facing the intermediate transfer member is the back surface. That is, an image transferred to the front surface of the transfer material is called a front image, and an image transferred to the back surface of the transfer material is called a back image.

First, an image forming process according to an embodiment of a first example of a double-sided image forming apparatus common to the first, third, fifth to eleventh, and eighteenth to twenty-fourth aspects of the present invention. The mechanism will be described with reference to FIGS. FIG. 1 shows claims 1, 3, and 5 of the present invention.
To 11 and the first common to claims 18 to 24.
FIG. 2 is a cross-sectional configuration view of a color image forming apparatus showing an embodiment of the double-sided image forming apparatus of FIG. 2, FIG. 2 is a side cross-sectional view of the image carrier of FIG. 1, and FIG. FIG. 3 is a diagram showing a toner image forming state in the forming apparatus, and FIG.
FIG. 3 is a view showing a toner image formation state when a back image formed on the image carrier is transferred onto the intermediate transfer body.
FIG. 3B is a diagram illustrating a toner image formation state when a front surface image is formed on an image carrier in synchronization with a back surface image on an intermediate transfer member. FIG. 3C is a diagram illustrating both surfaces on a transfer material. FIG. 3 is a diagram illustrating image formation.

In FIG. 1, 10 is a photosensitive drum as an image carrier, 11 is a scorotron charger as charging means for each color, 12 is an exposure optical system as image writing means for each color, and 13 is an exposure optical system for each color. A developing device 14a, an intermediate transfer belt as an intermediate transfer member, and 14c for transferring the toner image on the image carrier to the surface of the intermediate transfer member and the transfer material 1
A primary transfer unit as a secondary transfer unit, a secondary transfer unit 14g as a secondary transfer unit for retransferring the toner image on the intermediate transfer member to the back surface of the transfer material, and a paper charger 150 as a transfer material charging unit , 160 is a conveying unit having a separation claw 210 as a claw member and a spur 162 as a spur member, 17 is a fixing device as a fixing unit, and 250 is an intermediate transfer body cleaning blade 2
51 is an intermediate transfer member cleaning device that is an intermediate transfer member cleaning unit having 51.

The photosensitive drum 10, which is an image carrier, has a transparent conductive layer, a, on the outer periphery of a cylindrical substrate formed of a transparent member such as optical glass or transparent acrylic resin.
A photosensitive layer, such as an Si layer or an organic photosensitive layer (OPC), which is rotated at a linear speed of, for example, 80 to 400 mm / sec in a clockwise direction indicated by an arrow in FIG. Is done.

The photosensitive drum 10, as shown in FIG.
Flange members 10A and 1A at both ends for engaging and fixing it
The gear G integrated with the flange member 10B is supported by the bearings B1 and B2 fitted into the drum body 0B and supported rotatably by the drum shaft 30 erected and fixed to the apparatus main body. When driven by meshing with the drive gear, it is rotated at a constant speed in a predetermined direction.

The toner image forming means for forming a toner image on the image carrier is a scorotron charger 11, which is a charging means.
An exposure optical system 12 serving as an image writing unit and a developing unit 13 serving as a developing unit. These units constitute a set of images of each color of yellow (Y), magenta (M), cyan (C), and black (K). Four sets are provided for the forming process, and are arranged in the order of Y, M, C, and K with respect to the rotation direction of the photosensitive drum 10 indicated by the arrow in FIG.

The scorotron charger 11, which is a charging means for each color, has a control grid maintained at a predetermined potential and a discharge electrode 11a composed of, for example, a sawtooth electrode, and faces the photosensitive layer of the photosensitive drum 10. And installed
The charging operation (in the present embodiment, negative charging) is performed by corona discharge having the same polarity as that of the toner.
A uniform potential is given to 0. As the discharge electrode 11a, a wire electrode or a needle electrode may be used.

Exposure optical system 1 as image writing means for each color
2 indicates that the exposure position on the photosensitive drum 10 is the photosensitive drum 1 with respect to the scorotron charger 11 for each color described above.
It is arranged inside the photoconductor drum 10 so as to be located on the downstream side in the rotation direction of 0. As shown in FIG. 2, each exposure optical system 12 includes a plurality of LEDs (light emitting diodes) as light emitting elements of image exposure light (image writing light) arranged in the main scanning direction in parallel with the drum axis 30. Linear exposure elements 12a arranged in an array, and a light converging light transmitter (trade name: Selfoc lens array) 12b as an imaging element
And a lens holder 12c that holds the SELFOC lens array 12b, and is attached to the holding member 20. In addition to the exposure optical system 12 for each color, a transfer simultaneous exposure device 12d and a uniform exposure device 12e are attached to the holding member 20, and the photosensitive drum 1 is integrally formed.
0 is accommodated inside the light-transmitting substrate. The exposure optical system 12 for each color writes an image on the photosensitive layer of the photosensitive drum 10 from the back side in accordance with image data of each color read by a separate image reading device and stored in the memory.
An electrostatic latent image is formed thereon. As the exposure element 12a, L
In addition to the ED, it is also possible to use a plurality of light-emitting elements such as FL (phosphor light emission), EL (electroluminescence), and PL (plasma discharge) arranged in an array.
The emission wavelength of the light emitting element of the image exposure light (image writing light) is usually 780 to 90, which is highly transparent to the Y, M, and C toners.
In the present embodiment, since the image is written from the back surface, a shorter wavelength than 40 nm which does not have sufficient transparency to the color toner is used in this embodiment.
The wavelength may be from 0 to 780 nm. In addition, 80 of the image exposure light
% Or more is absorbed by the photosensitive layer of the photoconductor drum 10, so that the effect of reflection and absorption by the color toner on the surface of the photoconductor drum 10 can be neglected. Generally, the order of development of the color toner is preferably Y, M, C, and K from the relation of the color mixture to the toner image and the developing device 13. In FIG. 2, W
A is a lead wire from a light emitting element (LED) for image exposure light.

The developing device 13 as a developing means for each color keeps a predetermined gap with respect to the peripheral surface of the photosensitive drum 10 and rotates in the forward direction of the rotating direction of the photosensitive drum 10, for example, 0.5 to 1 mm in thickness. And a developing casing 131 formed of a cylindrical nonmagnetic stainless steel or aluminum material having an outer diameter of 15 to 25 mm, and a developing casing 138. Inside the developing casing 138, yellow (Y) and magenta ( M), cyan (C) and black (K) one-component or two-component developers. Each developing unit 13
The developing sleeve 131 has a predetermined gap, for example, 100 to 500 μm, from the photosensitive drum 10 by an abutting roller (not shown).
m, and a developing sleeve 131 having a layer thickness of 80 to 300 μm.
The upper developer is kept in non-contact with the photosensitive drum 10, and a non-contact reversal development is performed by applying a developing bias in which a DC voltage and an AC voltage are superposed on the developing sleeve 131. A toner image is formed on the drum 10.

An intermediate transfer belt 14a as an intermediate transfer member
Preferably has a volume resistivity of 10 ⁹ Ω · cm or more,
It is an endless belt of less than ¹² Ωcm, for example, a modified polyimide, a thermosetting polyimide, an ethylene-tetrafluoroethylene copolymer, polyvinylidene fluoride, a thickness of 0.1 to 0.1 in which a conductive material is dispersed in an engineering plastic such as nylon alloy. It is a seamless belt having a two-layer structure in which a 1.0 mm semiconductive film substrate is coated with a fluorine coating having a thickness of 5 to 50 μm, preferably as a toner filming preventing layer. In addition, as the base of the intermediate transfer belt 14a, a semiconductive rubber belt having a thickness of 0.5 to 2.0 mm in which a conductive material is dispersed in silicon rubber or urethane rubber or the like can be used. The intermediate transfer belt 14a includes a driving roller 1 that is a roller member.
The roller 40 is stretched around the secondary transfer facing roller 14j, the driven roller 14e, the guide roller 14f, and the tension roller 14i, and is rotated in a counterclockwise direction indicated by an arrow in FIG. The guide roller 14f, the driven roller 14e, the secondary transfer opposing roller 14j, and the drive roller 140 are rotated at fixed positions,
The tension roller 14i is movably supported and rotated by the elastic force of a spring or the like (not shown). The drive roller 140 is rotated by a drive motor (not shown), and the intermediate transfer belt 14a is driven to rotate. The rotation of the intermediate transfer belt 14a causes the secondary transfer opposing roller 14j, the driven roller 14e, the guide roller 14f, and the tension roller 14i to be driven and rotated. Belt slack of the rotating intermediate transfer belt 14a is tensioned by the tension roller 14i. The intermediate transfer belt 14a is driven by a driven roller 14e.
The recording paper P as a transfer material is supplied to a position where
The sheet is supported and conveyed by the intermediate transfer belt 14a. At the curvature portion KT at the end of the intermediate transfer belt 14a stretched around the driving roller 140 on the fixing device 17 side, the intermediate transfer belt 1
The recording paper P is separated from 4a.

A primary transfer device 14c as a primary transfer means for transferring the toner image on the image carrier to the surface of the intermediate transfer member or the transfer material is opposed to the photosensitive drum 10 with the intermediate transfer belt 14a interposed therebetween. A corona discharger provided between the intermediate transfer belt 14a and the photosensitive drum 10;
4b is formed. A DC voltage having a polarity opposite to that of the toner (positive polarity in the present embodiment) is applied to the primary transfer device 14c, and the toner image on the photosensitive drum 10 is transferred to the intermediate transfer belt 14a or to the recording paper P as a transfer material. Transfer to the surface. As the primary transfer device 14c, a transfer roller or a transfer blade can be used in addition to the corona discharge device.

A secondary transfer device 14g, which is a secondary transfer means for retransferring the toner image on the intermediate transfer member to the back surface of the transfer material, is constituted by a corona discharger, and is provided between the primary transfer device 14c and the driving roller 140. And is provided to face the secondary transfer facing roller 14j that is grounded with the intermediate transfer belt 14a interposed therebetween.
Polarity opposite to toner (positive polarity in this embodiment)
Is applied to transfer the toner image on the intermediate transfer belt 14a to the back surface of the recording paper P.

The paper charger 150, which is a transfer material charging means, is preferably formed of a saw-toothed electrode,
A DC voltage having the same polarity as that of the toner (in this embodiment, a negative polarity) is applied, and the recording paper P is charged and attracted to the intermediate transfer belt 14a. Let it. As the paper charger 150, in addition to the sawtooth electrode, a corona discharger, a paper charging brush capable of making contact with and release from the intermediate transfer belt 14a, a paper charging roller, or the like can be used.

The transport section 160 has a separation claw 210 as a transfer material separation assisting means and a spur 162 as a spur member.
The intermediate transfer belt 14 a is provided between the fixing device 17 and a curvature portion KT at the end of the intermediate transfer belt 14 a on the fixing device 17 side. Transport unit 160
Is transferred to the intermediate transfer belt 14 by heat from the fixing device 17.
a, the toner image carried on the intermediate transfer belt 14a becomes less likely to be transferred because the toner image tends to be fused, and the toner is prevented from being fixed on the intermediate transfer belt 14a.

The separation claw 210, which is a transfer material separation assisting means, is close to the curvature portion KT of the intermediate transfer belt 14a and has a predetermined distance from the intermediate transfer belt 14a, preferably 0.1 to 2.0.
When the recording paper P is separated from the intermediate transfer belt 14a, the recording paper P is bent toward the intermediate transfer belt 14a to be conveyed when the recording paper P is separated from the intermediate transfer belt 14a. To assist the curvature separation of the recording paper P.

The spur 162, which is a spur member, has a plurality of projections 162a on its peripheral surface, and is provided rotatably about a rotation support shaft 165. The spur 162 guides the back side of the recording sheet P to convey the recording sheet P, prevents the back side toner image of the recording sheet P having the toner image on both sides from being disturbed, and transfers the recording sheet P to the fixing device 17. The recording paper P is stably conveyed to the fixing device 17 while keeping the entering direction constant.

The separation claw 210 and the spur 162 are disposed on the side opposite to the photosensitive drum 10 with respect to the transfer material conveying surface on the intermediate transfer belt 14a or its extension surface.
It is also possible to provide spurs 162 as spur members on both sides of the transfer material conveying surface or an extension surface thereof.

A fixing device 17 serving as a fixing unit includes a first fixing roller 17a having a heater therein and a second fixing roller 1a.
7b, and by applying heat and pressure while nipping and transporting the recording paper P in a nip portion T between the first fixing roller 17a and the second fixing roller 17b. Then, the toner image on the recording paper P is fixed.

The intermediate transfer member cleaning device 250 serving as an intermediate transfer member cleaning means includes an intermediate transfer belt 14a.
The intermediate transfer belt cleaning blade 251 which is provided opposite to the guide roller 14f with the intermediary of the intermediate transfer belt 14a and which can abut and release the abutment on the intermediate transfer belt 14a, after the transfer remaining on the peripheral surface of the intermediate transfer belt 14a. Clean the toner. The intermediate transfer member cleaning blade 251 includes:
For example, it is formed of a rubber material such as urethane.

In order to detect a jam, which will be described in detail in each embodiment to be described later, a paper feed sensor PS1
However, the drum winding jam detection sensor PS2 faces the photoconductor drum 10 at a position immediately downstream of the photoconductor drum 10 in the rotation direction of the photoconductor drum 10 at a position where the photoconductor drum 10 comes into contact with the intermediate transfer belt 14a. A separation jam detection sensor PS3 is provided immediately downstream of the separation claw 210 in the rotation direction of the intermediate transfer belt 14a in the rotation direction of the intermediate transfer belt 14a, and a sheet discharge sensor PS4 is provided at a discharge side exit of the fixing device 17 at the discharge side. Are respectively provided.

Next, the image forming process will be described.

The photosensitive drum 10 is rotated clockwise as indicated by an arrow in FIG. 1 by starting a photosensitive member driving motor (not shown) at the start of image recording, and is simultaneously exposed by the charging action of a scorotron charger 11 for yellow (Y). Body drum 1
Application of a potential to 0 starts.

After the photosensitive drum 10 is applied with a potential, the Y exposure optical system 12 starts image writing with a first color signal, that is, an electric signal corresponding to the Y image data. An electrostatic latent image corresponding to the Y image of the original image is formed on the front surface.

The latent image is reversal-developed in a non-contact state by the Y developing unit 13, and a yellow (Y) toner image is formed on the photosensitive drum 10.

Next, a potential is applied to the photosensitive drum 10 from the Y toner image by the charging action of the magenta (M) scorotron charger 11, and the second color signal, that is, the M color signal, is applied by the M exposure optical system 12. Image writing is performed by an electric signal corresponding to the image data, and the magenta (M) toner image is superimposed on the yellow (Y) toner image by non-contact reversal development by the M developing unit 13. It is formed.

By the same process, the cyan (C) toner image corresponding to the third color signal is further superimposed by the cyan (C) scorotron charger 11, the exposure optical system 12 of C and the developing device 13 of C. The black (K) toner image corresponding to the fourth color signal is sequentially superimposed thereon by a black (K) scorotron charger 11, a K exposure optical system 12, and a K developing device 13. A superposed color toner image of four colors of yellow (Y), magenta (M), cyan (C) and black (K) is formed on the peripheral surface within one rotation of the photosensitive drum 10. .

These Y, M, C and K exposure optical systems 12
Image writing on the photosensitive layer of the photosensitive drum 10 is performed from the inside of the drum through the above-described translucent substrate. Therefore, the writing of the images corresponding to the second, third and fourth color signals is performed without any influence from the previously formed toner image, and is equivalent to the image corresponding to the first color signal. Can be formed.

In the transfer area 14b, the superimposed color toner image serving as the back side image formed on the photosensitive drum 10 as the image carrier by the above-described image forming process is formed.
The primary transfer unit 14c collectively transfers the toner onto an intermediate transfer belt 14a as an intermediate transfer body (FIG. 3A).
At this time, the photosensitive drum 1
The uniform exposure may be performed by the simultaneous transfer exposure device 12d provided inside the zero.

After the toner remaining on the peripheral surface of the photosensitive drum 10 after the transfer is subjected to charge removal by the photosensitive drum AC charge remover 16, the toner is transferred to a cleaning device 19, which is an image carrier cleaning means, or is transferred to the photosensitive drum 10. The toner is cleaned by a cleaning blade 19a made of a rubber material in contact with the toner, and collected by a screw 19b in a toner discharge container (not shown). Further, the peripheral surface of the photosensitive drum 10
For example, a uniform exposure device 12 before charging using a light emitting diode
The history of the photosensitive drum 10 in the previous image formation is eliminated by the exposure by e.

After the superimposed color toner image serving as the back side image is formed on the intermediate transfer belt 14a as described above, the front side image is continuously formed on the photosensitive drum 10 in the same manner as the above color image forming process. Is formed (FIG. 3B). On this occasion,
The image data is changed so that the front surface image formed on the photoconductor drum 10 becomes a mirror image with respect to the rear surface image formed on the photoconductor drum 10.

With the formation of a surface image on the photosensitive drum 10, recording paper P as a transfer material is sent out from a paper feed cassette 15 as a transfer material storage means by a feed roller 15a, and is used as a transfer material feeding means. Timing roller 1
5b, and the timing roller 15b drives the front surface image color toner image formed on the photosensitive drum 10 to synchronize with the back surface image color toner image carried on the intermediate transfer belt 14a. Transfer area 14
b. At this time, the fed recording paper P is charged to the same polarity as the toner by a paper charger 150 which is a transfer material charging means provided on the front surface side of the recording paper P, and is attracted to the intermediate transfer belt 14a to be transferred to the transfer area. 14b. By charging the paper with the same polarity as that of the toner, the toner is prevented from being attracted to the toner image on the intermediate transfer belt 14a and the toner image on the photosensitive drum 10, thereby preventing the toner image from being disturbed. The intermediate transfer member cleaning blade 251 of the intermediate transfer member cleaning device 250 is
When the toner image of the back surface image carried on 4a passes, it is released (separated) from intermediate transfer belt 14a.

In the transfer area 14b, the surface image on the photosensitive drum 10 is collectively applied to the surface of the recording paper P by the primary transfer device 14c to which a voltage having a polarity opposite to that of the toner (positive polarity in this embodiment) is applied. Transcribed. At this time, the back surface image on the intermediate transfer belt 14a is not transferred to the recording paper P but exists on the intermediate transfer belt 14a. At this time, in order to perform good transfer, uniform exposure is performed by a simultaneous transfer exposure device 12d using, for example, a light emitting diode, provided inside the photosensitive drum 10 so as to face the transfer area 14b. You may.

The recording paper P on which the color toner image has been transferred is conveyed to a secondary transfer unit 14g to which a voltage of the opposite polarity (positive polarity in this embodiment) to the toner is applied, and is transferred to the secondary transfer unit 14g. The back surface image on the peripheral surface of the intermediate transfer belt 14a is collectively retransferred to the back surface of the recording paper P by 14g (FIG. 3C).

The recording paper P on which the color toner images are formed on both sides is conveyed to the conveyance section 160 at a predetermined interval from the curvature of the curvature section KT of the intermediate transfer belt 14a.
, The intermediate transfer belt 1
4a, which is separated from the spur 16
2 to a fixing device 17 as a fixing unit, and is conveyed between a nip portion T between a first fixing roller 17a and a second fixing roller 17b, where heat and pressure are added at the nip portion T. The toner image on the recording paper P is fixed. The recording paper P on which double-sided image recording has been performed is sent upside down, and is discharged by a discharge roller 18 to a tray outside the apparatus.

The toner remaining on the peripheral surface of the intermediate transfer belt 14a after the transfer is cleaned by the intermediate transfer member cleaning blade 251 of the intermediate transfer member cleaning device 250 brought into contact with the intermediate transfer belt 14a.

Further, the toner remaining on the peripheral surface of the photosensitive drum 10 after the transfer is subjected to static elimination by the photosensitive drum AC static eliminator 16 and then cleaned by the cleaning device 19 to remove the toner. By 12e, the history of the photosensitive drum 10 in the previous image formation is eliminated, and the next image formation cycle is started.

Since the superimposed color toner images are collectively transferred by using the above-described method, color shift of the color image on the intermediate transfer belt 14a, scattering or rubbing of the toner, and the like are less likely to occur, and the image quality is reduced with less deterioration. Double-sided color image formation is performed.

Next, an embodiment of a double-sided image forming apparatus of a second example common to the second, fourth, twelfth to seventeenth and twenty-fifth to thirty-fifth aspects of the present invention will be described.
This will be described with reference to FIG. FIG. 4 shows claims 2, 4, 12 to 17, and 25 to 30 of the present invention.
FIG. 2 is a cross-sectional configuration diagram of a main part of a color image forming apparatus showing an embodiment of a double-sided image forming apparatus of a second example common to the first embodiment.

In the image forming apparatus of this embodiment, as shown in FIG. 4, a photosensitive drum 10b as a first image carrier for forming a toner image (backside toner image) as a backside image and a frontside image are formed. A photoconductor drum 10a as a second image carrier for forming a toner image (front toner image) is separately provided, and the back toner image formed on the photoconductor drum 10b has a polarity opposite to that of the toner (in the present embodiment). Is transferred to an intermediate transfer belt 114a, which is an intermediate transfer member, by a first primary transfer unit 114b, which is a first primary transfer unit to which a voltage having a positive polarity is applied. The recording paper P, which is a transfer material transferred from the paper cassette 15 by a feed roller 15a, is conveyed to a timing roller 15b as a transfer material feeding unit, and waits for the timing roller 15b, The driving of the timing roller 15b in synchronization with the surface toner image is supplied to the intermediate transfer belt 114a between the photosensitive drum 10b and the photosensitive drum 10a, a driven roller 14 across the intermediate transfer belt 114a
e, charging of the paper charger 150 provided opposite to
The recording paper P is attracted to the intermediate transfer belt 114a and is conveyed on the transfer material conveying surface of the intermediate transfer belt 114a.
The surface toner image formed on the photosensitive drum 10a in synchronization with the conveyance of the toner image is transferred to a second primary transfer unit to which a voltage having a polarity opposite to that of the toner (positive polarity in the present embodiment) is applied. After the primary transfer unit 114c transfers the toner image to the front surface of the recording paper P, the secondary transfer unit applies a reverse polarity (positive polarity in the present embodiment) voltage to the back toner image on the intermediate transfer belt 114a. Is re-transferred to the back surface of the recording paper P by the secondary transfer device 14g, and the front and back toner images are formed on the recording paper P, and the recording paper P having the color toner images formed on both surfaces is transferred to the intermediate transfer belt 114a. Is separated from the intermediate transfer belt 114a by the curvature of the curvature section KT and the separation claw 210 provided on the transport section 160 at a predetermined interval from the intermediate transfer belt 114a.
Is conveyed to a fixing device 17 as fixing means through a spur 162 which is a spur member provided in the first fixing roller 1.
The toner image on the recording paper P is fixed at the nip portion T between the second fixing roller 17a and the second fixing roller 17b to obtain a two-sided image. Also in this example, an intermediate transfer body cleaning device 250, which is an intermediate transfer body cleaning unit, is provided to face the guide roller 14f with the intermediate transfer belt 114a interposed therebetween, and can abut or release the intermediate transfer belt 114a. The intermediate transfer member cleaning blade 251 is brought into contact with the intermediate transfer belt 114a, and the transferred toner remaining on the peripheral surface of the intermediate transfer belt 114a is cleaned.

The photosensitive drums 10a and 10b and the intermediate transfer belt 114a in the image forming apparatus of this embodiment are the same as those of the first embodiment.
The same function and structure as those of the photosensitive drum 10 and the intermediate transfer belt 14a described in the image forming apparatus of the example are used. The intermediate transfer belt 114a is stretched in contact with the driving roller 140, the secondary transfer facing roller 14j, the driven roller 14e, the guide roller 14f, and the tension roller 14i.

A first toner image forming means for forming a toner image serving as a back image on a photosensitive drum 10b serving as a first image carrier, and a toner image serving as a second image carrier serving as a second image carrier The second toner image forming unit formed on the drum 10a includes yellow (Y), magenta (M), and cyan (C) similar to those used in the above-described image forming apparatus.
And four sets of scorotron chargers 11 (charging means), an exposure optical system 12 (image writing means), and a developing device 13 (developing means) for the black and black (K) image forming process.
0b and 10a are respectively used to form a toner image of a back side image and a toner image of a front side image.

In this embodiment, a sheet feed sensor PS11 is provided adjacent to the timing roller 15b and upstream of the recording sheet P in the conveying direction in order to detect a jam described in detail in each embodiment described later. Photoreceptor drum 10 as a body
a is located immediately downstream of the photosensitive drum 10a in the rotational direction of the photosensitive drum 10a at a position where the photosensitive drum 10a contacts the intermediate transfer belt 114a and faces the photosensitive drum 10a.
21 is a separation claw 210 provided near the curvature portion KT.
A separation jam detection sensor PS31 is provided immediately downstream of the intermediate transfer belt 114a in the rotation direction of the intermediate transfer belt 114a so as to face the intermediate transfer belt 114a, and a paper discharge sensor PS41 is provided at a paper discharge side exit of the fixing device 17.

Even when the above-described image forming apparatus is used, since the superimposed color toner images are collectively transferred, color misregistration of the color image on the intermediate transfer belt 14a, scattering or rubbing of the toner, and the like are less likely to occur, and image deterioration is reduced. A small and favorable double-sided color image is formed.

In each of the above-described examples of the image forming apparatus, the toner image is formed directly on the image carrier. However, an image carrier is provided separately from the image carrier, and the toner image formed on the image carrier is It may be carried on an image carrier. In addition, although a color image forming apparatus has been described as an example of each of the above image forming apparatuses, the present invention is not necessarily limited to this, and a monochrome image formed by a process similar to that described with reference to FIG. 1 or FIG. The present invention is also applied to a forming apparatus. Further, although the image writing unit is provided inside the image carrier, the first image carrier, and the second image carrier, it may be provided outside.

Further, in the image forming apparatus of the present invention, in addition to the double-sided image forming for forming an image on both sides of the transfer material as described in each of the above-described image forming apparatuses, the image forming apparatus may be provided on only one side of the front surface or the back surface of the transfer material. It goes without saying that single-sided image formation for forming an image can also be performed.

Embodiment 1 The processing at the time of a jam according to claim 1 will be described with reference to FIG.
This will be described with reference to FIG.

This embodiment shows the processing at the time of a jam such as a sending jam or a feeding jam in the image forming apparatus of the first example.

An accident in which the recording paper P is not supplied to the intermediate transfer belt 14a during double-sided image formation in which an image is formed on both sides of the recording paper P as a transfer material or during back-side image formation in which an image is formed only on the back side of the recording paper P More specifically, when the paper feed sensor PS1 does not detect the leading end of the recording paper P (does not become on) even if a predetermined time has elapsed after the feed roller 15a is turned on (operating state), and a paper jam occurs. Also, the sheet feed sensor PS1, which is turned on when the recording sheet P is on standby at the position of the timing roller 15b, is turned off even if a predetermined time has elapsed since the timing roller 15b was operated.
If a feeding jam that does not occur is generated, a toner image of a back surface image is formed on the photosensitive drum 10 by the toner image forming unit, and the intermediate transfer belt 1 is formed by the primary transfer unit 14c.
4A, the transfer of the toner image of the back side image to the back side image is immediately stopped, and the timing at which the recording paper P is supplied at the time of double-sided image formation or the back side image formation and the timing at which the recording paper P is conveyed on the intermediate transfer belt 14a are The intermediate transfer member cleaning blade 251 of the intermediate transfer member cleaning device 250 in the contact release state (separated state) is set to the contact state, and the intermediate transfer member cleaning blade 251 is set.
Cleaning of the intermediate transfer belt 14a by
The surface of the intermediate transfer belt 14 a cleaned by the intermediate transfer body cleaning blade 251 is
After passing through a position on the side surface of the intermediate transfer belt 14a of the fixing device 17 affected by heat from the intermediate transfer belt 14a, preferably, the entire surface of the intermediate transfer belt 14a is cleaned by the intermediate transfer member cleaning blade 251. Stop moving. The operation unit (not shown) displays a message indicating occurrence of a jam, a message, and the like. The user opens the front door (not shown) of the apparatus, and the jammed recording paper P is opened.
Remove.

For example, in the case where an odd number of double-sided prints having an A-4 (vertical) size width are to be performed for a normal maximum A-3 (vertical) size print width and the final recording paper P is a feeding jam, , FIG. FIG. 5 is a diagram illustrating exception processing according to claim 1 in the image forming apparatus of the first example. For example, in this embodiment, when three double-sided prints of A-4 (vertical) size width are performed, and when the third recording paper P is a feeding jam, as shown in FIG. Since the fourth toner image indicated by the one-dot chain line, which is supposed to be formed on the intermediate transfer belt 14a facing, is not formed, the intermediate transfer member cleaning blade 251 is operated after the occurrence of the jam, and the surface of the intermediate transfer belt 14a is There is no need to clean and wait for the cleaned surface to pass, and the machine can be stopped immediately.

As described above, even when an accident such as a so-called sending jam or a feeding jam occurs in which the transfer material is not supplied to the intermediate transfer member during the formation of the double-sided image or the rear surface image, the intermediate transfer member is immediately stopped. By stopping the cleaning after cleaning the intermediate transfer member, the toner image remaining on the intermediate transfer member in the portion facing the fixing unit is prevented from being fused to the intermediate transfer member due to the heat of the fixing unit. A good image can be stably obtained without the back surface of the transfer material being stained by the toner fused to the intermediate transfer member or the transfer of the toner image being not affected.

Second Embodiment The processing at the time of a jam according to the second embodiment will be described with reference to FIG.
This will be described with reference to FIG.

This embodiment shows a process of sending jam or feeding jam in the image forming apparatus of the second example.

An accident in which the recording paper P is not supplied to the intermediate transfer belt 114a during double-sided image formation in which images are formed on both sides of the recording paper P as a transfer material or during backside image formation in which an image is formed only on the backside of the recording paper P More specifically, when the paper feed sensor PS11 does not detect the leading edge of the recording paper P (does not enter the on-state) even if a predetermined time has elapsed after the feed-out roller 15a is turned on (operating state), and a paper jam occurs. Also, the sheet feed sensor PS11 which is turned on by the standby of the recording sheet P at the position of the timing roller 15b is turned off even if a predetermined time has elapsed since the timing roller 15b was operated.
If a feeding jam that does not cause ff occurs, the first toner image forming unit forms a toner image of the back surface image on the photosensitive drum 10b, and the second toner image forming unit forms a front image on the photosensitive drum 10a. Formation of toner image of the first 1
The transfer of the toner image of the back surface image to the intermediate transfer belt 114a by the next transfer unit 114b, and the second primary transfer unit 11
4c, the transfer of the toner image of the surface image is stopped immediately, and the surface of the intermediate transfer belt 114a cleaned by the intermediate transfer body cleaning blade 251 brought into contact with the intermediate transfer belt 114a is fixed to the fixing device 1.
After passing through a position on the side of the side of the intermediate transfer belt 14a of the fixing device 17 affected by heat from the intermediate transfer belt 7, the intermediate transfer belt 114a is preferably cleaned after the entire surface of the intermediate transfer belt 114a is cleaned by the intermediate transfer body cleaning blade 251. Stop moving. A display notifying the occurrence of a jam, a message, and the like are displayed on an operation unit (not shown), and the user opens the front door (not shown) of the apparatus and removes the jammed recording paper P.

As described above, even when an accident such as a so-called sending jam or a feeding jam occurs in which the transfer material is not supplied to the intermediate transfer member during the formation of the double-sided image or the rear surface image, the intermediate transfer member is immediately stopped. By stopping the cleaning after cleaning the intermediate transfer member, the toner image remaining on the intermediate transfer member in the portion facing the fixing unit is prevented from being fused to the intermediate transfer member due to the heat of the fixing unit. A good image can be stably obtained without the back surface of the transfer material being stained by the toner fused to the intermediate transfer member or the transfer of the toner image being not affected.

Third Embodiment The processing at the time of a jam according to the third embodiment will be described with reference to FIG.
This will be described with reference to FIG.

This embodiment shows the processing of the jam around the drum in the image forming apparatus of the first example.

When forming a double-sided image in which images are formed on both sides of a recording sheet P as a transfer material, or in forming a back side image in which an image is formed only on the back side of the recording sheet P, the recording sheet P
0, the sheet is not conveyed normally, specifically, the drum winding jam detection sensor PS2 is
When a so-called drum winding jam occurs, which detects the recording paper P on the upper side, the photosensitive drum 10 is moved, and a toner image of a surface image is formed on the photosensitive drum 10 by the toner image forming means. The transfer of the toner image of the front surface image to the recording paper P by the transfer roller 14c, the transfer of the toner image of the back surface image to the recording paper P by the secondary transfer device 14g, and the supply of the recording paper P by the timing roller 15b are immediately stopped. The intermediate transfer member cleaning blade of the intermediate transfer member cleaning device 250 is in the contact release state (separated state) at the timing when the recording paper P is being conveyed on the intermediate transfer belt 14a when forming the double-sided image or the rear surface image. The cleaning of the intermediate transfer belt 14a by the intermediate transfer body cleaning blade 251 is started with the intermediate transfer belt 251 in the contact state. Transfer member cleaning blade 251
The surface of the intermediate transfer belt 14 a cleaned by the fixing device 17 is affected by heat from the fixing device 17.
After passing through the position on the side of the intermediate transfer belt 14a,
Preferably, the movement of the intermediate transfer belt 14a is stopped after the entire surface of the intermediate transfer belt 14a is cleaned by the intermediate transfer member cleaning blade 251. A display notifying the occurrence of a jam, a message, and the like are displayed on an operation unit (not shown), and the user opens the front door (not shown) of the apparatus and removes the jammed recording paper P.

As described above, even when an accident such as a so-called drum wrap jam occurs that the transfer material is not normally conveyed due to the adsorption of the transfer material during the formation of the double-sided image or the back-side image, the intermediate transfer member is immediately transferred to the intermediate transfer member. By stopping the cleaning after cleaning the intermediate transfer member without stopping, the toner image remaining on the intermediate transfer member in the portion facing the fixing unit is prevented from being fused to the intermediate transfer member due to the heat of the fixing unit. Thus, a good image can be stably obtained without the back surface of the transfer material being stained by the toner fused to the intermediate transfer member or the transfer of the toner image being not affected.

Fourth Embodiment The processing at the time of a jam according to the fourth embodiment will be described with reference to FIG.
This will be described with reference to FIG.

This embodiment shows the processing in the jam around the drum in the image forming apparatus of the second example.

The recording paper P is the second image carrier when forming a double-sided image in which images are formed on both sides of the recording paper P as a transfer material or when forming a backside image in which an image is formed only on the backside of the recording paper P. An accident in which the toner is not normally transported by being attracted to the photosensitive drum 10a, specifically, the jam detection sensor P
S21 detects the recording paper P on the photosensitive drum 10a,
When a so-called drum wrap jam occurs, the movement of the photosensitive drum 10b as the first image carrier, the movement of the photosensitive drum 10a as the second image carrier, and the exposure by the first toner image forming means. Formation of a toner image of a back side image on the body drum 10b, formation of a toner image of a front side image on the photosensitive drum 10a by a second toner image forming unit,
Transfer of the toner image of the back surface image to the intermediate transfer belt 114a by the next transfer unit 114b, transfer of the toner image of the front surface image to the recording paper P by the second primary transfer unit 114c, and back surface toner image by the secondary transfer unit 14g Transfer of the recording paper P by the timing roller 15b is stopped immediately, and the surface of the intermediate transfer belt 114a cleaned by the intermediate transfer body cleaning blade 251 brought into contact with the intermediate transfer belt 114a is fixed. Device 17
After passing through a position on the side of the intermediate transfer belt 14a of the fixing device 17 that is affected by heat from the intermediate transfer belt 114a, preferably, the entire surface of the intermediate transfer belt 114a is cleaned by the intermediate transfer member cleaning blade 251. Stop moving. A display notifying the occurrence of a jam, a message, and the like are displayed on an operation unit (not shown), and the user opens the front door (not shown) of the apparatus and removes the jammed recording paper P.

As described above, even when an accident such as a so-called drum wrap jam occurs, the transfer material is not normally transported due to the adsorption of the transfer material to the second image carrier during double-sided image formation or back-side image formation. Does not stop immediately, but stops after cleaning the intermediate transfer member, so that the toner image remaining on the intermediate transfer member in the portion facing the fixing unit is fused to the intermediate transfer member by the influence of the heat of the fixing unit. As a result, a good image can be stably obtained without the back surface of the transfer material being stained by the toner fused to the intermediate transfer member or the transfer of the toner image being not affected.

Embodiment 5 The processing at the time of a jam according to claims 5 to 11 will be described with reference to FIG. FIG.
FIG. 4 is an explanatory diagram of processing at the time of a jam related to No. 1;

This embodiment shows a process at the time of a conveyance jam in the image forming apparatus of the first example.

The conveyance of the recording paper P by the intermediate transfer belt 14a is normal at the time of forming a double-sided image where images are formed on both sides of the recording paper P as a transfer material or at the time of forming a back side image where an image is formed only on the back side of the recording paper P. In this case, the leading end of the recording paper P is wrapped around the intermediate transfer belt 14a at the curvature portion KT of the intermediate transfer belt 14a as shown by hatching in FIG. 6, and the separation jam detection sensor PS3 is turned on by the intermediate transfer belt 14a. When the recording paper P is detected above, that is, when a separation jam occurs, the photosensitive drum 10 is driven, the intermediate transfer belt 14a is driven, a toner image of a surface image is formed by a toner image forming unit, and the primary transfer unit 14c is used. The transfer of the toner image of the front surface image to the recording paper P and the transfer of the toner image of the back surface image to the recording paper P by the secondary transfer unit 14g are immediately stopped.

Thereafter, a display notifying the occurrence of a jam or a message is displayed on an operation unit (not shown). The user opens the front door (not shown) of the apparatus main body, and pushes the lever 331 to which the separation claw 210 is attached. A stopper 33 indicated by a dotted line in FIG. 6 around the fixed shaft J3 by a link mechanism (not shown).
The recording paper P lifted and jammed by manual operation from the position (predetermined position) locked by 1a to the position shown by the solid line against the spring 332 is placed on the intermediate transfer belt 14a, and is manually moved from the intermediate transfer belt 14a. It is pulled out of the device by operation and discharged. After discharging the jammed recording paper P, the separation claw 21
Return 0 to the predetermined position.

When the recording paper P is long and its rear end does not pass through the contact surface between the intermediate transfer belt 14a and the photosensitive drum 10, the intermediate transfer belt 14a is supported on both sides as necessary. The lever 311 connected to the support frame 71 on the front side (the front side in FIG. 6) of the support frame 71 is held by a stopper 311a indicated by a dotted line in FIG. From the holding position to the position shown by the solid line locked by the stopper 311b, and the intermediate transfer belt 14a is moved to the position (predetermined position) shown by the dotted line in FIG.
, The intermediate transfer belt 14a is rotated by a manual operation from the photosensitive drum 10 by rotating around the drive roller 140 from the position shown by the solid line. The support frame 71 on the front side (the front side in FIG. 6) is provided with a shaft hole 71a.
a manual rotary shaft 141 integrally formed with the drive roller 140 through the support frame 71 is provided so as to protrude from the support frame 71, and the separation claw 210 attached to the lever 331 described above.
Is lifted up, and the drive roller 140 is manually rotated clockwise by a rotation knob (not shown) attached to the manual rotary shaft 141 to rotate the intermediate transfer belt 14a in a clockwise direction opposite to the direction of conveyance of the recording paper P during image formation. Then, the jammed recording paper P is placed on the intermediate transfer belt 14a, and the jammed recording paper P is manually pulled out of the intermediate transfer belt 14a and discharged. When the intermediate transfer belt 14a is rotated clockwise by a rotation knob (not shown),
The intermediate transfer member cleaning blade 251 is brought into contact with the intermediate transfer belt 14a by a link mechanism (not shown). After discharging the jammed recording paper P,
The separation claw 210 is returned to the predetermined position, and the lever 311 is rotated to return the intermediate transfer belt 14a to the predetermined position.

When the front door (not shown) is closed, the intermediate transfer belt 14a is automatically driven for a predetermined time, during which the intermediate transfer belt 14a is cleaned by the intermediate transfer member cleaning blade 251 which is in contact with the intermediate transfer belt 14a. Then, the driving of the intermediate transfer belt 14a is stopped. Here, the predetermined time means that at least the surface of the intermediate transfer belt 14a cleaned by the intermediate transfer member cleaning blade 251 passes through a position on the side of the intermediate transfer belt 14a of the fixing device 17 which is affected by heat from the fixing device 17. The cleaning time is preferably the time until the entire surface of the intermediate transfer belt 14a is cleaned by the intermediate transfer member cleaning blade 251.

In the event that the recording paper P is not properly conveyed by the intermediate transfer belt 14a when forming a double-sided image or when forming a rear-side image, recording on the photosensitive drum 10 is performed by the jam detection sensor PS2 around the drum. When the paper P is detected, and a drum-wrapped jam whose front end is indicated by a dashed line (a) in FIG. 6 and whose rear end is indicated by a dashed line (b),
Driving of the photosensitive drum 10, driving of the intermediate transfer belt 14a, formation of a toner image of the surface image by the toner image forming means, transfer of the toner image of the surface image to the recording paper P by the primary transfer device 14c, and secondary transfer device 14g, transfer of toner image of back side image to recording paper P, and timing roller 15
The supply of the recording paper P by b is immediately stopped.

Thereafter, a display notifying the occurrence of a jam, a message, and the like are displayed on an operation unit (not shown). The user opens the front door (not shown) of the apparatus main body, and the intermediate transfer belt 1 is opened.
The lever 311 connected to the support frame 71 on the front side (the front side in FIG. 6) of the support frame 71 supporting both sides 4a is indicated by a dotted line in FIG. The intermediate transfer belt 14a is moved from the holding position locked by the stopper 311a to the position indicated by the solid line locked by the stopper 311b, and the intermediate transfer belt 14a is moved from the position (predetermined position) indicated by the dotted line in FIG. After rotating about the roller 140 to separate the intermediate transfer belt 14a from the photosensitive drum 10 by manual operation, the timing roller 15b is rotated clockwise by manual operation, and the timing roller 1 is rotated.
The trailing end portion of the jammed recording paper P sandwiched between the intermediate transfer belt 14a and the intermediate transfer belt 14a
The jammed recording paper P is pulled out of the apparatus from above the intermediate transfer belt 14a by manual operation and discharged. After discharging the jammed recording paper P, the lever 311 is rotated to return the intermediate transfer belt 14a to a predetermined position. When the rear end of the recording sheet P in which the recording sheet P has been jammed is not sandwiched between the timing rollers 15b, the rotation of the timing roller 15b is unnecessary, and the stop of the timing roller 15b at the time of a jam is not necessarily required.

When the front door (not shown) is closed, the intermediate transfer belt 14a is automatically driven for a predetermined time, during which the intermediate transfer belt 14a is cleaned by the intermediate transfer member cleaning blade 251 which is in contact with the intermediate transfer belt 14a. Then, the driving of the intermediate transfer belt 14a is stopped. Here, the predetermined time means that at least the surface of the intermediate transfer belt 14a cleaned by the intermediate transfer body cleaning blade 251 is in contact with the intermediate transfer belt 14a of the fixing device 17.
This is the time required to pass the position on the side surface, preferably the time required to clean the entire surface of the intermediate transfer belt 14a by the intermediate transfer member cleaning blade 251.

Also, when the double-sided image formation or the back-side image formation is performed, an accident that the recording paper P is not properly conveyed by the intermediate transfer belt 14a, specifically, the timing roller 15b
After the is driven, the passage of the recording paper P by the paper ejection sensor PS4 is not detected even after a predetermined time according to the size of the recording paper P elapses. For example, the front end is indicated by a dashed line (c) in FIG. When a jump jam occurs in the secondary transfer unit 14g indicated by a dashed line (d), the photosensitive drum 10 is driven, the intermediate transfer belt 14a is driven, and a toner image forming unit forms a toner image on a surface image. Transfer of a toner image of a surface image onto recording paper P by transfer device 14c, and secondary transfer device 1
The transfer of the toner image of the back side image to the recording paper P by 4 g is immediately stopped.

Thereafter, a display notifying the occurrence of a jam, a message, and the like are displayed on an operation unit (not shown).
The lever 311 connected to the support frame 71 on the front side (the front side in FIG. 6) of the support frame 71 supporting both sides 4a is indicated by a dotted line in FIG. The intermediate transfer belt 14a is moved from the holding position locked by the stopper 311a to the position indicated by the solid line locked by the stopper 311b, and the intermediate transfer belt 14a is moved from the position (predetermined position) indicated by the dotted line in FIG. After rotating about the roller 140 and manually separating the intermediate transfer belt 14a from the photosensitive drum 10, the lever 321 to which the secondary transfer unit 14g is attached is pivoted about the fixed shaft J2 by a link mechanism (not shown). The stopper 321a indicated by a dotted line in FIG.
The recording paper P which has been lifted and jammed by manual operation from the position (predetermined position) where the recording paper P is locked against the spring 322 is placed on the intermediate transfer belt 14a, and the jammed recording paper P is transferred to the intermediate transfer belt 14a. The belt 14a is manually pulled out of the apparatus and discharged. After the jammed recording paper P is discharged, the secondary transfer device 14g is returned to the predetermined position, and the lever 311 is rotated to return the intermediate transfer belt 14a to the predetermined position.

When the front door (not shown) is closed, the intermediate transfer belt 14a is automatically driven for a predetermined time, during which the intermediate transfer belt 14a is cleaned by the intermediate transfer member cleaning blade 251 which is in contact with the intermediate transfer belt 14a. Then, the driving of the intermediate transfer belt 14a is stopped. Here, the predetermined time means that at least the surface of the intermediate transfer belt 14a cleaned by the intermediate transfer body cleaning blade 251 is in contact with the intermediate transfer belt 14a of the fixing device 17.
This is the time required to pass the position on the side surface, preferably the time required to clean the entire surface of the intermediate transfer belt 14a by the intermediate transfer member cleaning blade 251.

As described above, even when an accident such as a conveyance jam in which the transfer material is not normally conveyed by the intermediate transfer member occurs during the formation of the double-sided image or the rear surface image, the intermediate transfer is automatically performed after the completion of the jam processing. The body is cleaned, and the toner image remaining on the intermediate transfer body in a portion facing the fixing unit is prevented from being fused to the intermediate transfer body due to the influence of the heat of the fixing unit. A good image can be stably obtained without the back surface of the transfer material being stained or the transfer of the toner image being not affected.

Embodiment 6 The processing at the time of a jam according to claims 12 to 17 will be described with reference to FIG. FIG. 7 is an explanatory diagram of a process at the time of a jam according to the twelfth to seventeenth aspects.

This embodiment shows a process at the time of a conveyance jam in the image forming apparatus of the second example.

The transfer of the recording paper P by the intermediate transfer belt 114a is normal during the double-sided image formation in which an image is formed on both sides of the recording paper P as a transfer material or the back side image formation in which an image is formed only on the back side of the recording paper P. Is not performed, specifically, when the leading end of the recording paper P is
As shown by hatching in FIG.
4a, when the separation jam detection sensor PS31 detects the recording paper P on the intermediate transfer belt 114a, that is, when a so-called separation jam occurs, the movement of the photosensitive drum 10b as the first image carrier and the second image Movement of the photosensitive drum 10a as a carrier, formation of a toner image of a back surface image on the photosensitive drum 10b by the first toner image forming means, and formation of a front image on the photosensitive drum 10a by the second toner image forming means Formation of a toner image, transfer of the toner image of the back side image to the intermediate transfer belt 114a by the first primary transfer device 114b, transfer of the toner image of the front surface image to the recording paper P by the second primary transfer device 114c, Then, the transfer of the back toner image by the secondary transfer unit 14g is immediately stopped.

Thereafter, a display notifying the occurrence of a jam, a message, and the like are displayed on an operation unit (not shown). A stopper 4 indicated by a dotted line in FIG.
From the position (predetermined position) locked by 31a, the spring 432
The recording sheet P lifted and jammed by a manual operation to the position shown by the solid line is placed on the intermediate transfer belt 114a against
The intermediate transfer belt 114a is manually pulled out of the apparatus and discharged. After discharging the jammed recording paper P, the separation claw 210 is returned to a predetermined position.

When the recording paper P is long and its rear end does not pass through the contact surface between the intermediate transfer belt 114a and the photosensitive drum 10a, the intermediate transfer belt 114a is supported on both sides as necessary. The lever 4 connected to the support frame 171 on the front side (the front side in FIG. 7) of the support frame 171
7 with the knob D from the holding position locked by the stopper 411a indicated by the dotted line in FIG. From the position shown by the dotted line (predetermined position) in FIG. 7 to the position shown by the solid line.
The intermediate transfer belt 114a rotates around the center 40 and is manually separated from the photosensitive drum 10a. The support frame 171 on the front side (front side in FIG. 7) is provided with a shaft hole 171a.
The manual rotary shaft 141 formed integrally with the support frame 17
1, and is provided with the lever 43 described above.
1, the separation roller 210 is lifted up, and the drive roller 140 is manually rotated clockwise by a rotation knob (not shown) attached to the manual rotation shaft 141 so that the intermediate transfer belt 114 a is moved to the recording paper P at the time of image formation. , The jammed recording paper P is put on the intermediate transfer belt 114a, and the jammed recording paper P is manually pulled out of the intermediate transfer belt 114a and discharged. When the intermediate transfer belt 114a is rotated clockwise by a rotation knob (not shown), the intermediate transfer member cleaning blade 251 is released from contact with the intermediate transfer belt 114a (separated state) by a link mechanism (not shown).
It is said. After discharging the jammed recording paper P, the separation claw 210
Is returned to the predetermined position, and the lever 411 is rotated to return the intermediate transfer belt 114a to the predetermined position.

When the front door (not shown) is closed, the intermediate transfer belt 114a is automatically driven for a predetermined time, during which the intermediate transfer belt 114a is cleaned by the intermediate transfer member cleaning blade 251 which is in contact with the intermediate transfer belt 114a. Then, the driving of the intermediate transfer belt 114a is stopped. Here, the predetermined time is at least a time required for the surface of the intermediate transfer belt 114 a cleaned by the intermediate transfer member cleaning blade 251 to pass through a position on the side of the intermediate transfer belt 114 a of the fixing device 17, preferably the intermediate transfer member This is the time until the entire surface of the intermediate transfer belt 114a is cleaned by the cleaning blade 251.

In addition, when the double-sided image formation or the back-side image formation is performed, the recording paper P is not properly conveyed by the intermediate transfer belt 114a. Specifically, the recording is performed on the photosensitive drum 10a by the drum winding jam detection sensor PS21. When the paper P is detected and a drum winding jam occurs, the leading end of which is indicated by a dashed line (a) in FIG. 7 and the trailing end of the photosensitive drum 10b is indicated by a dashed line (b). The movement of the photosensitive drum 10a as the second image carrier,
Formation of a toner image of a backside image on photoconductor drum 10b by first toner image forming means, formation of a toner image of a frontside image on photoconductor drum 10a by second toner image forming means, first primary transfer Transfer belt 1 by the heater 114b
The transfer of the toner image of the backside image to the recording paper P by the second primary transfer unit 114c, the transfer of the backside toner image by the secondary transfer unit 14g, and the timing roller 15b. The supply of the recording paper P is immediately stopped.

Thereafter, a display notifying the occurrence of a jam, a message, and the like are displayed on an operation unit (not shown), and the user opens a front door (not shown) of the apparatus main body, and the intermediate transfer belt 1 is opened.
The lever 411 connected to the support frame 171 on the front side (the front side in FIG. 7) of the support frame 171 supporting both sides of the support frame 14a is
Holding the knob D, from the holding position where it is locked to the stopper 411a indicated by the dotted line in FIG.
Depress to the position shown by the solid line locked by the stopper 411b,
After the intermediate transfer belt 114a is rotated about the drive roller 140 from the position (predetermined position) indicated by the dotted line in FIG. 7 to the position indicated by the solid line, the intermediate transfer belt 114a is manually separated from the photosensitive drum 10a. When the timing roller 15b is rotated clockwise by manual operation, the jammed recording paper P sandwiched between the timing rollers 15b
Is fed onto the intermediate transfer belt 114a, and the jammed recording paper P on the intermediate transfer belt 114a is manually pulled out from the intermediate transfer belt 114a to the outside of the apparatus and discharged. After the jammed recording paper P is discharged, the lever 411
To return the intermediate transfer belt 114a to a predetermined position. When the rear end of the recording sheet P in which the recording sheet P has been jammed is not sandwiched between the timing rollers 15b, the rotation of the timing roller 15b is unnecessary, and the stop of the timing roller 15b at the time of a jam is not necessarily required.

When the front door (not shown) is closed, the intermediate transfer belt 114a is automatically driven for a predetermined period of time, during which the intermediate transfer belt 114a is cleaned by the intermediate transfer member cleaning blade 251 which is in contact with the intermediate transfer belt 114a. Then, the driving of the intermediate transfer belt 114a is stopped. Here, the predetermined time is at least a time required for the surface of the intermediate transfer belt 114 a cleaned by the intermediate transfer member cleaning blade 251 to pass through a position on the side of the intermediate transfer belt 114 a of the fixing device 17, preferably the intermediate transfer member This is the time until the entire surface of the intermediate transfer belt 114a is cleaned by the cleaning blade 251.

In the event that the recording paper P is not conveyed properly by the intermediate transfer belt 114a during the formation of the double-sided image or the rear-side image, more specifically, the timing roller 15
After b is driven, the passage of the recording paper P by the paper ejection sensor PS41 is not detected even after a predetermined time according to the size of the recording paper P has passed.
If a jam occurs in the secondary transfer unit 14g whose rear end is indicated by a dashed line (d), the photosensitive drum 10b as the first image carrier is moved, and the photosensitive drum as the second image carrier is moved. 10a, formation of a toner image of a back side image on the photoconductor drum 10b by the first toner image forming unit, formation of a toner image of a front surface image on the photoconductor drum 10a by the second toner image forming unit, first Transfer of the toner image of the back side image to the intermediate transfer belt 114a by the primary transfer device 114b, transfer of the toner image of the front surface image to the recording paper P by the second primary transfer device 114c, and by the secondary transfer device 14g Immediately stops the transfer of the back toner image.

Thereafter, a display notifying the occurrence of a jam or a message is displayed on an operation unit (not shown), and the user opens the front door (not shown) of the apparatus main body, and the intermediate transfer belt 1 is opened.
The lever 411 connected to the support frame 171 on the front side (the front side in FIG. 7) of the support frame 171 supporting both sides of the support frame 14a is
Holding the knob D, from the holding position where it is locked to the stopper 411a indicated by the dotted line in FIG.
Depress to the position shown by the solid line locked by the stopper 411b,
After the intermediate transfer belt 114a is rotated about the drive roller 140 from the position (predetermined position) indicated by the dotted line in FIG. 7 to the position indicated by the solid line, the intermediate transfer belt 114a is manually separated from the photosensitive drum 10a. The lever 421 to which the secondary transfer device 14g is attached is moved from a position (predetermined position) where the lever 421 is locked by a stopper 421a indicated by a dotted line in FIG.
The recording sheet P lifted and jammed by a manual operation to the position shown by the solid line against the spring 422 is transferred to the intermediate transfer belt 114a.
The jammed recording paper P is placed on the intermediate transfer belt 114.
a Manually pull it out of the device from above and discharge it. After discharging the jammed recording paper P, the secondary transfer device 14g is returned to a predetermined position, and the lever 411 is rotated to return the intermediate transfer belt 114a to the predetermined position.

When the front door (not shown) is closed, the intermediate transfer belt 114a is automatically driven for a predetermined time, during which the intermediate transfer belt 114a is cleaned by the intermediate transfer member cleaning blade 251 brought into contact with the intermediate transfer belt 114a. Then, the driving of the intermediate transfer belt 114a is stopped. Here, the predetermined time is at least a time required for the surface of the intermediate transfer belt 114 a cleaned by the intermediate transfer member cleaning blade 251 to pass through a position on the side of the intermediate transfer belt 114 a of the fixing device 17, preferably the intermediate transfer member This is the time until the entire surface of the intermediate transfer belt 114a is cleaned by the cleaning blade 251.

As described above, even when an accident such as a conveyance jam in which the transfer material is not normally conveyed by the intermediate transfer member occurs during the formation of the double-sided image or the rear surface image, the intermediate transfer is automatically performed after the jam processing is completed. The body is cleaned, and the toner image remaining on the intermediate transfer body in a portion facing the fixing unit is prevented from being fused to the intermediate transfer body due to the influence of the heat of the fixing unit. A good image can be stably obtained without the back surface of the transfer material being stained or the transfer of the toner image being not affected.

Embodiment 7 The processing at the time of a jam according to claims 18 to 24 will be described with reference to FIG. FIG. 8 is an explanatory diagram of the processing at the time of a jam according to claims 18 to 24.

This embodiment shows the processing of the conveyance jam in the image forming apparatus of the first example.

In forming a double-sided image in which images are formed on both sides of the recording paper P as a transfer material, the conveyance of the recording paper P by the intermediate transfer belt 14a is not normally performed. FIG. 8 shows a state where the curvature portion KT of the intermediate transfer belt 14a is used.
The separation jam detection sensor PS3 wraps around the intermediate transfer belt 14a as indicated by hatching
When the recording paper P is detected on the recording paper P, that is, when a separation jam occurs, the photosensitive drum 10 is driven, the intermediate transfer belt 14a is driven, and a toner image of a surface image is formed by a toner image forming unit. The transfer of the toner image of the back side image to the recording paper P by the secondary transfer unit 14g is stopped immediately.

Thereafter, a display notifying the occurrence of a jam or a message is displayed on an operation unit (not shown). The user opens the front door (not shown) of the apparatus main body, and pushes the lever 331 to which the separation claw 210 is attached. A stopper 33 indicated by a dotted line in FIG.
The recording paper P lifted and jammed by manual operation from the position (predetermined position) locked by 1a to the position shown by the solid line against the spring 332 is placed on the transfer material conveying surface of the intermediate transfer belt 14a. Then, the separation claw 210 is returned to the predetermined position.

If the recording paper P is long and its rear end does not pass through the contact surface between the intermediate transfer belt 14a and the photosensitive drum 10, the intermediate transfer belt 14a is supported on both sides as necessary. The lever 311 connected to the support frame 71 on the front side (the front side in FIG. 8) of the support frame 71 is engaged with the stopper 311a indicated by a dotted line in FIG. From the holding position to the position shown by the solid line locked by the stopper 311b, and the intermediate transfer belt 14a is moved to the position shown by the dotted line in FIG. 8 (predetermined position).
, The intermediate transfer belt 14a is rotated by a manual operation from the photosensitive drum 10 by rotating around the drive roller 140 from the position shown by the solid line. The support frame 71 on the front side (the front side in FIG. 8) is provided with a shaft hole 71a.
a manual rotary shaft 141 integrally formed with the drive roller 140 through the support frame 71 is provided so as to protrude from the support frame 71, and the separation claw 210 attached to the lever 331 described above.
Is lifted, and the drive roller 140 is manually rotated clockwise by a rotation knob (not shown) attached to the manual rotary shaft 141, so that the intermediate transfer belt 14a is rotated in a clockwise direction opposite to the conveying direction of the recording paper P during image formation. The separation claw 210 is returned to a predetermined position while the jammed recording paper P is placed on the transfer material conveying surface of the intermediate transfer belt 14a, and the lever 311 is rotated to move the intermediate transfer belt 14a to the predetermined position. return. When the intermediate transfer belt 14a is rotated clockwise by a rotation knob (not shown), the intermediate transfer member cleaning blade 251 is brought into contact with the intermediate transfer belt 14a by a link mechanism (not shown). Is done.

After the recording paper P jammed by the manual operation as described above is returned to the transfer material conveying surface on the intermediate transfer belt 14a, and the front door (not shown) is closed, the photosensitive drum 10, the intermediate transfer belt 14a and the fixing member are fixed. The apparatus 17 is automatically driven for a predetermined time, and the jammed recording paper P is discharged out of the duplex image forming apparatus. Here, the predetermined time means that at least the surface of the intermediate transfer belt 14a cleaned by the intermediate transfer member cleaning blade 251 passes through a position on the side of the intermediate transfer belt 14a of the fixing device 17, and the intermediate transfer belt 14a is manually operated. This is the time until the jammed recording paper P returned to the upper transfer material conveying surface is discharged to the outside of the double-sided image forming apparatus via the fixing device 17. Preferably, the jammed recording paper P is removed from the fixing device 17. This is the time from when the intermediate transfer belt 14a is completely cleaned by the intermediate transfer member cleaning blade 251 after the sheet is discharged outside the duplex image forming apparatus.

When forming a double-sided image, the intermediate transfer belt 1
8A, the recording paper P is detected on the photosensitive drum 10 by the drum wrap jam detection sensor PS2.
When the drum winding jam indicated by the dashed-dotted line (a) and the dashed-dotted line (b) occurs, the photosensitive drum 10 is driven, the intermediate transfer belt 14a is driven, and the toner image of the surface image is formed by the toner image forming means. Formation, transfer of the toner image of the front surface image to the recording paper P by the primary transfer device 14c, transfer of the toner image of the back surface image to the recording paper P by the secondary transfer device 14g,
The supply of the recording paper P by the timing roller 15b is immediately stopped.

Thereafter, a display notifying the occurrence of a jam, a message, and the like are displayed on an operation unit (not shown). The user opens the front door (not shown) of the apparatus main body, and the
The lever 311 connected to the support frame 71 on the front side (front side in FIG. 8) of the support frame 71 supporting both sides 4a is indicated by a dotted line in FIG. The intermediate transfer belt 14a is moved from the holding position locked by the stopper 311a to the position indicated by the solid line locked by the stopper 311b, and the intermediate transfer belt 14a is moved from the position (predetermined position) indicated by the dotted line in FIG. After rotating about the roller 140 to manually separate the intermediate transfer belt 14a from the photosensitive drum 10, the timing roller 15b is rotated clockwise by manual operation, and the timing roller 1 is rotated.
The trailing end portion of the jammed recording paper P sandwiched between the intermediate transfer belts 14a and 5b is sent out onto the intermediate transfer belt 14a.
Then, the lever 311 is rotated to return the intermediate transfer belt 14a to a predetermined position. When the rear end of the recording sheet P in which the recording sheet P has been jammed is not sandwiched between the timing rollers 15b, the rotation of the timing roller 15b is unnecessary, and the stop of the timing roller 15b at the time of a jam is not necessarily required.

When the jammed recording paper P is returned to the transfer material conveying surface on the intermediate transfer belt 14a by manual operation and the front door (not shown) is closed, the photosensitive drum 10, the intermediate transfer belt 14a and the fixing device 17 are closed. The recording paper P is automatically driven for a predetermined time, and the jammed recording paper P is discharged out of the duplex image forming apparatus. Here, the predetermined time means that at least the surface of the intermediate transfer belt 14a cleaned by the intermediate transfer member cleaning blade 251 passes through a position on the side of the intermediate transfer belt 14a of the fixing device 17, and the intermediate transfer belt 14a is manually operated. This is the time until the jammed recording paper P returned to the upper transfer material conveying surface is discharged to the outside of the double-sided image forming apparatus via the fixing device 17. Preferably, the jammed recording paper P is removed from the fixing device 17. This is the time from when the intermediate transfer belt 14a is completely cleaned by the intermediate transfer member cleaning blade 251 after the sheet is discharged outside the duplex image forming apparatus.

When forming a double-sided image, the intermediate transfer belt 1
4a, the conveyance of the recording paper P is not performed normally. Specifically, even after the timing roller 15b is driven, even if a predetermined time corresponding to the size of the recording paper P elapses, the recording paper P is detected by the paper ejection sensor PS4. When the passage of P is not detected, for example, when a jam occurs in the secondary transfer unit 14g whose front end is indicated by a dashed line (c) in FIG. Driving the intermediate transfer belt 14a, forming a toner image of the surface image by the toner image forming means, transferring the toner image of the surface image onto the recording paper P by the primary transfer device 14c, and recording paper P by the secondary transfer device 14g
Immediately stops the transfer of the toner image of the back side image to the toner image.

Thereafter, a display notifying the occurrence of a jam, a message, and the like are displayed on an operation unit (not shown). The user opens the front door (not shown) of the apparatus main body, and the intermediate transfer belt 1 is opened.
The lever 311 connected to the support frame 71 on the front side (front side in FIG. 8) of the support frame 71 supporting both sides 4a is indicated by a dotted line in FIG. The intermediate transfer belt 14a is moved from the holding position locked by the stopper 311a to the position indicated by the solid line locked by the stopper 311b, and the intermediate transfer belt 14a is moved from the position (predetermined position) indicated by the dotted line in FIG. After rotating about the roller 140 and manually separating the intermediate transfer belt 14a from the photosensitive drum 10, the lever 321 to which the secondary transfer unit 14g is attached is pivoted about the fixed shaft J2 by a link mechanism (not shown). The stopper 321a indicated by a dotted line in FIG.
After the recording paper P lifted and jammed by a manual operation from the position (predetermined position) locked by the spring to the position shown by the solid line against the spring 322 is placed on the transfer material conveying surface of the intermediate transfer belt 14a, While returning the next transfer device 14g to a predetermined position,
The lever 311 is rotated to return the intermediate transfer belt 14a to a predetermined position.

After the jammed recording paper P is returned to the transfer material conveying surface on the intermediate transfer belt 14a and the front door (not shown) is closed, the photosensitive drum 10, the intermediate transfer belt 14a, and the fixing device 17 are closed. The recording paper P is automatically driven for a predetermined time, and the jammed recording paper P is discharged out of the duplex image forming apparatus. Here, the predetermined time means that at least the surface of the intermediate transfer belt 14a cleaned by the intermediate transfer member cleaning blade 251 passes through a position on the side of the intermediate transfer belt 14a of the fixing device 17, and the intermediate transfer belt 14a is manually operated. This is the time until the jammed recording paper P returned to the upper transfer material conveying surface is discharged to the outside of the double-sided image forming apparatus via the fixing device 17. Preferably, the jammed recording paper P is removed from the fixing device 17. This is the time from when the intermediate transfer belt 14a is completely cleaned by the intermediate transfer member cleaning blade 251 after the sheet is discharged outside the duplex image forming apparatus.

As described above, even when a conveyance jam occurs in which the transfer material is not normally conveyed by the intermediate transfer body during the double-sided image formation, the jammed transfer material is not taken out of the apparatus as it is. By discharging the toner to the outside of the apparatus (outside the apparatus) through the fixing unit, the jam processing is performed without soiling the hands and the inside of the apparatus with the unfixed toner on the intermediate transfer member.

Eighth Embodiment The processing at the time of a jam according to claims 25 to 30 will be described with reference to FIG. FIG. 9 is an explanatory diagram of processing at the time of a jam according to claims 25 to 30.

This embodiment shows the processing of the conveyance jam in the image forming apparatus of the second example.

In forming a double-sided image in which images are formed on both sides of a recording sheet P as a transfer material, an accident in which the recording sheet P is not properly conveyed by the intermediate transfer belt 114a, specifically, the leading end of the recording sheet P At the curvature portion KT of the intermediate transfer belt 114a, as shown by hatching in FIG.
When the separation jam detection sensor PS31 detects the recording paper P on the intermediate transfer belt 114a, that is, when a so-called separation jam occurs, the movement of the photosensitive drum 10b as the first image carrier and the second image carrier Movement of the photosensitive drum 10a as a body, formation of a toner image of a back side image on the photosensitive drum 10b by the first toner image forming unit, and toner of a front surface image on the photosensitive drum 10a by the second toner image forming unit Formation of an image, transfer of the toner image of the back side image to the intermediate transfer belt 114a by the first primary transfer device 114b, transfer of the toner image of the front surface image to the recording paper P by the second primary transfer device 114c, and The transfer of the back toner image by the secondary transfer device 14g is immediately stopped.

Thereafter, a display for notifying the occurrence of a jam, a message, and the like are displayed on an operation unit (not shown). A stopper 4 shown by a dotted line in FIG. 9 around a fixed shaft J31 by a link mechanism (not shown).
From the position (predetermined position) locked by 31a, the spring 432
After the recording paper P, which has been lifted and jammed by a manual operation to the position shown by the solid line, is placed on the transfer material conveying surface of the intermediate transfer belt 114a, the separation claw 210 is returned to a predetermined position.

When the recording paper P is long and its rear end does not pass through the contact surface between the intermediate transfer belt 114a and the photosensitive drum 10a, the intermediate transfer belt 114a is supported on both sides as necessary. The lever 4 connected to the support frame 171 on the front side (the front side in FIG. 9) of the support frame 171
9 with the knob D from the holding position locked by the stopper 411a shown by the dotted line in FIG. 9 around the rotation axis J11 to the position shown by the solid line locked by the stopper 411b, and the intermediate transfer belt 114a From the position (predetermined position) indicated by the dotted line in FIG. 9 to the position indicated by the solid line in FIG.
The intermediate transfer belt 114a rotates around the center 40 and is manually separated from the photosensitive drum 10a. A shaft hole 171a is provided in the support frame 171 on the front side (front side in FIG. 9), and the drive roller 14 is inserted through the shaft hole 171a.
The manual rotary shaft 141 formed integrally with the support frame 17
1, and is provided with the lever 43 described above.
1 is lifted, and the drive roller 140 is manually rotated clockwise by a rotating knob (not shown) attached to the manual rotary shaft 141 to rotate the intermediate transfer belt 114a to the recording paper P at the time of image formation. After the jammed recording paper P is placed on the transfer material conveying surface of the intermediate transfer belt 114a, the separating claw 210 is returned to a predetermined position, and the lever 411 is rotated to rotate the intermediate transfer. The belt 114a is returned to a predetermined position. When the intermediate transfer belt 114a is rotated clockwise by a rotation knob (not shown), the intermediate transfer member cleaning blade 251 is moved by the link mechanism (not shown) to the intermediate transfer belt 114.
From a, the contact is released (separated state).

When the front door (not shown) is closed after the recording paper P jammed by the manual operation as described above is returned to the transfer material conveying surface on the intermediate transfer belt 114a, the photosensitive drums 10a,
10b, the intermediate transfer belt 114a, and the fixing device 17 are automatically driven for a predetermined time, and the jammed recording paper P is discharged out of the duplex image forming apparatus. Here, the predetermined time means that at least the surface of the intermediate transfer belt 114a cleaned by the intermediate transfer member cleaning blade 251 passes through the position on the side of the intermediate transfer belt 114a of the fixing device 17, and the intermediate transfer belt 114 is manually operated.
a, the jammed recording paper P returned to the transfer material transport surface on
This is the time until the recording paper P that has been jammed is discharged out of the duplex image forming apparatus through the fixing device 17.
This is the time until the entire surface of the intermediate transfer belt 114a is cleaned by the intermediate transfer member cleaning blade 251.

When forming a double-sided image, the intermediate transfer belt 1
An accident that the conveyance of the recording paper P by 14a is not performed normally,
Specifically, the recording paper P is detected on the photoreceptor drum 10a by the drum wrap jam detection sensor PS21, and a drum wrap jam whose front end is shown by the dashed line (a) in FIG. 9 and whose rear end is shown by the dashed line (b) occurs. In this case, the movement of the photosensitive drum 10b as the first image carrier, the movement of the photosensitive drum 10a as the second image carrier, and the transfer of the back side image to the photosensitive drum 10b by the first toner image forming means. Formation of toner image, photoreceptor drum 10a by second toner image forming means
Formation of a toner image of a surface image on a first primary transfer unit 11
4b, the transfer of the toner image of the back surface image to the intermediate transfer belt 114a, and the recording paper P by the second primary transfer device 114c.
Of the front side image to the toner image, the transfer of the back side toner image by the secondary transfer unit 14g, and the timing roller 15b
Supply of the recording paper P is immediately stopped.

Thereafter, a display notifying the occurrence of a jam, a message, and the like are displayed on an operation unit (not shown). The user opens the front door (not shown) of the apparatus main body, and the intermediate transfer belt 1 is opened.
The lever 411 connected to the support frame 171 on the front side (the front side in FIG. 9) of the support frame 171 supporting the side 14a on both sides is provided.
Holding the knob D, from the holding position where it is locked to the stopper 411a indicated by the dotted line in FIG.
Depress to the position shown by the solid line locked by the stopper 411b,
After the intermediate transfer belt 114a is rotated about the drive roller 140 from the position (predetermined position) indicated by the dotted line in FIG. 9 to the position indicated by the solid line, and the intermediate transfer belt 114a is manually separated from the photosensitive drum 10a. When the timing roller 15b is rotated clockwise by manual operation, the jammed recording paper P pinched by the
After the rear end portion of the intermediate transfer belt 114a is sent out onto the transfer material transporting surface of the intermediate transfer belt 114a and placed thereon, the lever 411 is rotated to return the intermediate transfer belt 114a to a predetermined position. When the rear end of the recording sheet P in which the recording sheet P has been jammed is not sandwiched between the timing rollers 15b, the rotation of the timing roller 15b is unnecessary, and the stop of the timing roller 15b at the time of a jam is not necessarily required.

After the jammed recording paper P is returned to the transfer material conveying surface on the intermediate transfer belt 114a and the front door (not shown) is closed, the photosensitive drums 10a and 10b, the intermediate transfer belt 114a, and the fixing device are closed. 17 is automatically driven for a predetermined time, and the jammed recording paper P is discharged out of the duplex image forming apparatus. Here, the predetermined time means that at least the surface of the intermediate transfer belt 114 a cleaned by the intermediate transfer body cleaning blade 251 is
The jammed recording paper P that has passed through the position on the side of the intermediate transfer belt 114a and returned to the transfer material conveying surface on the intermediate transfer belt 114a by manual operation is
7 until the recording paper P is ejected out of the duplex image forming apparatus.
Is discharged outside the duplex image forming apparatus through the intermediate transfer belt cleaning blade 251.
This is the time until the entire surface 4a is cleaned.

When forming a double-sided image, the intermediate transfer belt 1
An accident that the conveyance of the recording paper P by 14a is not performed normally,
Specifically, after the timing roller 15b is driven, the passage of the recording sheet P by the sheet ejection sensor PS41 is not detected even after a predetermined time corresponding to the size of the recording sheet P has elapsed. (C), the dashed line at the rear end (d)
When the jump jam into the secondary transfer unit 14g occurs as shown by the arrow, the movement of the photosensitive drum 10b as the first image carrier, the movement of the photosensitive drum 10a as the second image carrier,
Formation of a toner image of a backside image on photoconductor drum 10b by first toner image forming means, formation of a toner image of a frontside image on photoconductor drum 10a by second toner image forming means, first primary transfer Transfer belt 1 by the heater 114b
The transfer of the back side toner image to the recording paper P by the second primary transfer unit 114c, the transfer of the back side image toner image to the recording paper P, and the transfer of the back side toner image by the secondary transfer unit 14g are immediately stopped. .

Thereafter, a display notifying the occurrence of a jam, a message, and the like are displayed on an operation unit (not shown). The user opens the front door (not shown) of the apparatus main body, and the intermediate transfer belt 1 is opened.
The lever 411 connected to the support frame 171 on the front side (the front side in FIG. 7) of the support frame 171 supporting both sides of the support frame 14a is
Holding the knob D, from the holding position where it is locked to the stopper 411a indicated by the dotted line in FIG.
Depress to the position shown by the solid line locked by the stopper 411b,
After the intermediate transfer belt 114a is rotated about the drive roller 140 from the position (predetermined position) indicated by the dotted line in FIG. 9 to the position indicated by the solid line, and the intermediate transfer belt 114a is manually separated from the photosensitive drum 10a. The lever 421 to which the secondary transfer unit 14g is attached is moved from a position (predetermined position) where the lever 421 is locked by a stopper 421a indicated by a dotted line in FIG.
The recording sheet P lifted and jammed by a manual operation to the position shown by the solid line against the spring 422 is transferred to the intermediate transfer belt 114a.
Then, the secondary transfer device 14g is returned to the predetermined position, and the lever 411 is rotated to return the intermediate transfer belt 114a to the predetermined position.

After the recording paper P jammed by the manual operation is returned to the transfer material conveying surface on the intermediate transfer belt 114a and the front door (not shown) is closed, the photosensitive drums 10a and 10b, the intermediate transfer belt 114a and the fixing device are closed. 17 is automatically driven for a predetermined time, and the jammed recording paper P is discharged out of the duplex image forming apparatus. Here, the predetermined time means that at least the surface of the intermediate transfer belt 114 a cleaned by the intermediate transfer body cleaning blade 251 is
The jammed recording paper P that has passed through the position on the side of the intermediate transfer belt 114a and returned to the transfer material conveying surface on the intermediate transfer belt 114a by manual operation is
7 until the recording paper P is ejected out of the duplex image forming apparatus.
Is discharged outside the duplex image forming apparatus through the intermediate transfer belt cleaning blade 251.
This is the time until the entire surface 4a is cleaned.

As described above, even in the event of a conveyance jam in which the transfer of the transfer material by the intermediate transfer member is not performed properly during the formation of the double-sided image, the jammed transfer material is not taken out of the apparatus as it is. By discharging the toner through the fixing means to the outside of the apparatus (outside the apparatus), the jam processing is performed without soiling the hands and the inside of the apparatus with the unfixed toner on the intermediate transfer member.

By using the double-sided image forming apparatus described with reference to FIG. 1 or FIG. 4, there is a problem in the double-sided image forming apparatus using the conventional double-sided reversing feeding apparatus, that is, Slow speed ● Reliability of paper (transfer material) transport is low and jams are easy to occur ● If a jam occurs, the paper path is long, so there is a lot of wasted paper and the jam handling is difficult ● Application There is a limit to the type of paper that can be used, and it cannot be used for small-size paper such as thick paper, thin paper, and postcards, or irregular-size paper. ● The paper passage is contaminated by the fixing oil, which is a problem especially in color. And the process is not stable, and the following effects are achieved.

Since there is no waiting time for reversing the paper (transfer material), it is possible to continuously perform image formation on both sides of the paper, and the first printing speed on both sides is increased. Because there is no need to feed paper,
Paper feeding reliability is greatly improved. Also, there is no contamination of the paper passage route by the fixing oil and no heat brought into the machine. ○ Since double-sided printing is possible with the same feeding system as for single-sided printing, there is no restriction on the type of transfer material. The number of sheets passing through the fixing unit at the time of both sides is half that at the time of one side, so that the fixing power consumption is reduced.

[0134]

According to the first or second aspect of the present invention, even when an accident such as a feeding jam or a feeding jam in which the transfer material is not supplied to the intermediate transfer member occurs during double-sided image formation or back-side image formation, the intermediate transfer is performed. When the intermediate transfer body is cleaned and then stopped, the toner image remaining on the intermediate transfer body facing the fixing unit is fused to the intermediate transfer body due to the heat of the fixing unit. Will not be worn,
A good image can be stably obtained without the back surface of the transfer material being stained by the toner fused on the intermediate transfer member or the transfer of the toner image being not affected.

According to the third aspect of the present invention, even when an accident such as a drum winding jam occurs in which the transfer material is attracted to the image carrier and is not conveyed properly during the formation of the double-sided image or the rear-side image, the intermediate transfer member is immediately moved. By stopping the cleaning after cleaning the intermediate transfer member, the toner image remaining on the intermediate transfer member in the portion facing the fixing unit is prevented from being fused to the intermediate transfer member due to the heat of the fixing unit. Thus, a good image can be stably obtained without the back surface of the transfer material being stained by the toner fused to the intermediate transfer member or the transfer of the toner image being not affected.

According to the fourth aspect of the present invention, even when an accident such as a drum winding jam occurs in which the transfer material is attracted to the second image carrier and is not normally conveyed during the formation of the double-sided image or the back-side image, the intermediate transfer is performed. When the intermediate transfer body is cleaned and then stopped, the toner image remaining on the intermediate transfer body facing the fixing unit is fused to the intermediate transfer body due to the heat of the fixing unit. As a result, a good image can be stably obtained without the back surface of the transfer material being stained by the toner fused to the intermediate transfer body or the transfer of the toner image being not affected. .

According to the fifth to seventeenth aspects, even when a conveyance jam in which the transfer material is not normally conveyed by the intermediate transfer member occurs during double-sided image formation or rear-side image formation, the jam occurs after the jam processing is completed. The intermediate transfer member is automatically cleaned, and the toner image remaining on the intermediate transfer member in a portion facing the fixing unit is prevented from being fused to the intermediate transfer member due to the heat of the fixing unit. A good image can be stably obtained without the back surface of the transfer material being stained by the fused toner or the transfer of the toner image being not affected.

According to the eighteenth to thirty-seventh aspects, even in the event of a conveyance jam in which the transfer of the transfer material by the intermediate transfer member is not performed properly during the double-sided image formation, the jammed transfer material is directly discharged to the outside of the machine. Instead of taking it out, it is discharged out of the machine (outside the machine) through the fixing means,
Jam processing is performed without soiling the hands and the inside of the apparatus with unfixed toner on both sides of the transfer material or the intermediate transfer body.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a color image forming apparatus according to a first embodiment of the present invention, which is common to the first, third, fifth to eleventh, and eighteenth to twenty-eighth aspects of the present invention. It is sectional drawing.

FIG. 2 is a side sectional view of the image carrier of FIG. 1;

FIG. 3 is a diagram illustrating a toner image forming state in the double-sided image forming apparatus of FIG. 1;

FIG. 4 is a cross-sectional view of a color image forming apparatus showing an embodiment of a double-sided image forming apparatus according to a second example which is common to claims 2, 4, 12 to 17, and 25 to 30 of the present invention; It is principal part sectional drawing.

FIG. 5 is a diagram illustrating exception processing according to claim 1 in the image forming apparatus of the first example.

FIG. 6 is an explanatory diagram of processing at the time of a jam according to claims 5 to 11;

FIG. 7 is an explanatory diagram of processing at the time of a jam according to claims 12 to 17;

FIG. 8 is an explanatory diagram of processing at the time of a jam according to claims 18 to 24;

FIG. 9 is an explanatory diagram of a process at the time of a jam according to claims 25 to 30;

[Explanation of symbols]

 10, 10a, 10b Photoconductor drum 11 Scorotron charger 12 Exposure optical system 13 Developing device 14a, 114a Intermediate transfer belt 14c Primary transfer device 14g Secondary transfer device 15b Timing roller 17 Fixing device 114b First primary transfer device 114c Second primary transfer device 210 Separation claw 250 Intermediate transfer member cleaning device 251 Intermediate transfer member cleaning blade P Recording paper PS1, PS11 Feed sensor PS2, PS21 Drum wrap jam detection sensor PS3, PS31 Separation jam detection sensor PS4, PS41 Discharge Paper sensor

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Tetsu Haneda 2970 Ishikawacho, Hachioji-shi, Tokyo Konica Corporation F-term (reference) 2H027 DA38 DC11 DC14 EB04 EC20 ED19 ED24 ED25 EE02 EE07 EF09 EF11 EK04 EK10 FA13 2H028 BA06 BA16 BB04 2H032 AA02 BA09 BA19 BA21 BA23 BA25 BA30 CA01 CA13

Claims (30)

[Claims] An image carrier for carrying a toner image formed by a toner image forming means on a surface thereof; a toner image on the image carrier being transferred, and carrying the transferred toner image on a surface; A belt-shaped intermediate transfer body that supports and conveys a transfer material, a transfer material supply unit that supplies the transfer material to the intermediate transfer body, and a surface of the intermediate transfer body or the transfer material that transfers the toner image on the image carrier to the intermediate transfer body Primary transfer means for transferring the toner image on the intermediate transfer body to a back surface of the transfer material; fixing means for fixing the toner image on the transfer material; A double-sided image forming apparatus having an intermediate transfer body cleaning unit for cleaning the body, when forming a double-sided image forming an image on both sides of the transfer material, or when forming a back side image forming an image only on the back surface of the transfer material When an accident occurs in which the transfer material is not supplied to the intermediate transfer body, the formation of the toner image by the toner image forming unit and the transfer of the toner image by the primary transfer unit are immediately stopped, and the intermediate transfer body Cleaning of the intermediate transfer body by a cleaning unit is started, and at least after the surface of the intermediate transfer body cleaned by the intermediate transfer body cleaning unit passes a position of the fixing unit on the side of the intermediate transfer body, A double-sided image forming apparatus wherein the movement of the intermediate transfer member is stopped. 2. A first image carrier for carrying a toner image formed by a first toner image forming means on a surface thereof, and a first image carrier for carrying a toner image formed by a second toner image forming means on a surface thereof. A belt-like intermediate transfer member that transfers the toner image on the first image bearing member, carries the transferred toner image on the surface, and supports and transports a transfer material; Transfer material supply means for supplying a transfer material to the intermediate transfer member, first primary transfer means for transferring a toner image on the first image carrier to the intermediate transfer member, and second image carrier A second primary transfer unit for transferring a toner image on a body to a front surface of the transfer material; a secondary transfer unit for retransferring a toner image on the intermediate transfer body to a back surface of the transfer material; Fixing means for fixing the upper toner image, and cleaning the intermediate transfer member A double-sided image forming apparatus having an intermediate transfer member cleaning unit, wherein the transfer material is used when forming a double-sided image where images are formed on both sides of the transfer material or when forming a back surface image where an image is formed only on the back surface of the transfer material. When an accident occurs in which the toner image is not supplied to the intermediate transfer member, the toner image formation by the first and second toner image forming units and the transfer of the toner image by the first and second primary transfer units are performed. Immediately stop, and at least stop the movement of the intermediate transfer body after the surface of the intermediate transfer body cleaned by the intermediate transfer body cleaning unit passes the position of the fixing unit on the side of the intermediate transfer body side. A two-sided image forming apparatus. 3. An image carrier for carrying a toner image formed by a toner image forming means on a surface thereof, a toner image on the image carrier being transferred, and carrying the transferred toner image on a surface. A belt-shaped intermediate transfer body that supports and conveys a transfer material, a transfer material supply unit that supplies the transfer material to the intermediate transfer body, and a surface of the intermediate transfer body or the transfer material that transfers the toner image on the image carrier to the intermediate transfer body Primary transfer means for transferring the toner image on the intermediate transfer body to a back surface of the transfer material; fixing means for fixing the toner image on the transfer material; A double-sided image forming apparatus having an intermediate transfer body cleaning unit for cleaning the body, when forming a double-sided image forming an image on both sides of the transfer material, or when forming a back side image forming an image only on the back surface of the transfer material When an accident occurs in which the transfer material is not normally transported due to adsorption of the transfer material to the image carrier, movement of the image carrier, formation of a toner image by the toner image forming unit, transfer of the toner image by the primary transfer unit ,
The transfer of the toner image by the secondary transfer unit and the supply of the transfer material by the transfer material supply unit are immediately stopped, and the cleaning of the intermediate transfer body by the intermediate transfer body cleaning unit is started. Double-sided image formation, wherein the movement of the intermediate transfer body is stopped after the surface of the intermediate transfer body cleaned by the intermediate transfer body cleaning unit passes through a position of the fixing unit on the side of the intermediate transfer body. apparatus. 4. A first image carrier for carrying on the surface a toner image formed by the first toner image forming means, and a first image carrier for carrying on the surface a toner image formed by the second toner image forming means. A belt-like intermediate transfer member that transfers the toner image on the first image bearing member, carries the transferred toner image on the surface, and supports and transports a transfer material; Transfer material supply means for supplying a transfer material to the intermediate transfer member, first primary transfer means for transferring a toner image on the first image carrier to the intermediate transfer member, and second image carrier A second primary transfer unit for transferring a toner image on a body to a front surface of the transfer material; a secondary transfer unit for retransferring a toner image on the intermediate transfer body to a back surface of the transfer material; Fixing means for fixing the upper toner image, and cleaning the intermediate transfer member A double-sided image forming apparatus having an intermediate transfer member cleaning unit, wherein the transfer material is used when forming a double-sided image where images are formed on both sides of the transfer material or when forming a back surface image where an image is formed only on the back surface of the transfer material. When an accident occurs in which the first image carrier and the second image carrier are not normally transported due to being attracted to the second image carrier, the toner images formed by the first and second toner image forming units are moved. Formation, transfer of a toner image by the first and second primary transfer means, transfer of a toner image by the secondary transfer means,
And immediately stopping the supply of the transfer material by the transfer material supply unit, and at least the surface of the intermediate transfer body cleaned by the intermediate transfer body cleaning unit is positioned at a side of the fixing unit on the side of the intermediate transfer body. Wherein the movement of the intermediate transfer member is stopped after passing through. 5. An image carrier for carrying a toner image formed by a toner image forming means, a toner image on the image carrier being transferred, carrying the transferred toner image, and supporting a transfer material. A belt-shaped intermediate transfer body to be conveyed; primary transfer means for transferring the toner image on the image carrier to the surface of the intermediate transfer body or the transfer material; and a transfer material for transferring the toner image on the intermediate transfer body to the transfer material. A double-sided image forming apparatus, comprising: a secondary transfer unit that retransfers to the back surface of the transfer material; a fixing unit that fixes a toner image on the transfer material; and an intermediate transfer body cleaning unit that cleans the intermediate transfer body. During the double-sided image formation for forming an image on both sides of the transfer material or the backside image formation for forming an image only on the back surface of the transfer material, an accident occurs in which the transfer of the transfer material by the intermediate transfer body is not performed normally. In this case, the driving of the image carrier, the driving of the intermediate transfer member, the formation of the toner image by the toner image forming unit, and the transfer of the toner image by the primary transfer unit and the secondary transfer unit are immediately stopped. And a manual operation of discharging the transfer material that has not been normally conveyed to the outside of the double-sided image forming apparatus, and after the transfer material is discharged out of the double-sided image forming apparatus by the manual operation, And a cleaning device for cleaning the intermediate transfer member by driving the intermediate transfer member cleaning unit for a predetermined time. 6. The image forming apparatus according to claim 6, wherein the manual operation includes an operation of separating the image carrier from the intermediate transfer member and an operation of bringing the image carrier into contact with the intermediate transfer member. 6. The double-sided image forming apparatus according to 5. 7. The double-sided image forming apparatus according to claim 6, wherein the manual operation includes an operation of rotating the intermediate transfer body. 8. The intermediate transfer member cleaning means is capable of contacting and releasing the intermediate transfer member, and releasing the intermediate transfer member cleaning member when rotating the intermediate transfer member by the manual operation. The double-sided image forming apparatus according to any one of claims 5 to 7, wherein the image forming apparatus is configured to: 9. The two-sided recording medium according to claim 5, wherein the manual operation includes an operation of driving a transfer material supply unit that supplies the transfer material to the intermediate transfer body. Image forming device. 10. The duplex image forming apparatus according to claim 5, wherein the manual operation includes an operation of moving the secondary transfer unit. 11. The method according to claim 5, wherein the manual operation includes an operation of moving a transfer material separation assisting unit that assists separation of the transfer material when the transfer material is separated from the intermediate transfer body. The double-sided image forming apparatus according to any one of claims 10 to 10. 12. A first image carrier for carrying a toner image formed by a first toner image forming means, and a second image carrier for carrying a toner image formed by a second toner image forming means. A belt-shaped intermediate transfer body that transfers the toner image on the first image carrier, carries the transferred toner image, and supports and conveys a transfer material; and the first image carrier. A first primary transfer unit for transferring the upper toner image to the intermediate transfer body, a second primary transfer unit for transferring the toner image on the second image carrier to the surface of the transfer material, Secondary transfer means for retransferring the toner image on the intermediate transfer member to the back surface of the transfer material; fixing means for fixing the toner image on the transfer material; intermediate transfer member cleaning means for cleaning the intermediate transfer member A double-sided image forming apparatus having An accident occurred in which the transfer of the transfer material by the intermediate transfer body was not performed properly during double-sided image formation in which an image is formed on both sides of a copying material or during backside image formation in which an image is formed only on the backside of the transfer material. In this case, the first and second image carriers are driven, the intermediate transfer member is driven, a toner image is formed by the first and second toner image forming units, and the first and second images are formed.
The manual operation of immediately stopping the transfer of the toner image by the next transfer unit and the retransfer of the toner image by the secondary transfer unit and discharging the transfer material that has not been normally transported to the outside of the double-sided image forming apparatus is performed. After the transfer material is discharged out of the duplex image forming apparatus by the manual operation, the intermediate transfer body and the intermediate transfer body cleaning unit are driven for a predetermined time to clean the intermediate transfer body. Image forming apparatus. 13. The method according to claim 13, wherein the manual operation includes an operation of separating the second image bearing member and the intermediate transfer member;
13. The double-sided image forming apparatus according to claim 12, further comprising an operation of bringing the image carrier into contact with the intermediate transfer member. 14. The double-sided image forming apparatus according to claim 13, wherein the manual operation includes an operation of rotating the intermediate transfer body. 15. The double-sided printing method according to claim 12, wherein the manual operation includes an operation of driving a transfer material supply unit that supplies the transfer material to the intermediate transfer body. Image forming device. 16. The apparatus according to claim 12, wherein said manual operation includes an operation of moving said secondary transfer means.
6. The double-sided image forming apparatus according to any one of 5. 17. The image forming apparatus according to claim 12, wherein the manual operation includes an operation of moving a transfer material separation assisting unit that assists separation of the transfer material when the transfer material is separated from the intermediate transfer body. 17. The double-sided image forming apparatus according to any one of claims 16 to 16. 18. An image carrier for carrying a toner image formed by a toner image forming means, a toner image transferred on the image carrier, carrying the transferred toner image, and supporting a transfer material. A belt-shaped intermediate transfer body to be conveyed; primary transfer means for transferring the toner image on the image carrier to the surface of the intermediate transfer body or the transfer material; and a transfer material for transferring the toner image on the intermediate transfer body to the transfer material. A two-sided image forming apparatus having a secondary transfer means for re-transferring to the back surface of the transfer material and a fixing means for fixing a toner image on the transfer material, wherein when forming an image on both surfaces of the transfer material, the intermediate transfer member When an accident occurs in which the transfer of the transfer material is not performed normally due to the drive of the image carrier, the drive of the intermediate transfer body, the formation of a toner image by the toner image forming unit, the primary transfer unit, 2 above A stop operation for immediately stopping the transfer of the toner image by the next transfer means is performed. After the stop operation, the transfer material that has not been normally transported is transferred by the intermediate transfer body normally. In this case, a manual operation for returning to the transfer material transport surface on the intermediate transfer member is enabled, and after the transfer material is returned to the transfer material transport surface on the intermediate transfer member by the manual operation, the image carrier, A two-sided image forming apparatus, wherein the intermediate transfer body and the fixing unit are driven for a predetermined time, and the transfer material is discharged out of the two-sided image forming apparatus. 19. The image forming apparatus according to claim 19, wherein the manual operation includes an operation of separating the image carrier from the intermediate transfer member and an operation of bringing the image carrier into contact with the intermediate transfer member. 19. The two-sided image forming apparatus according to 18. 20. The double-sided image forming apparatus according to claim 19, wherein the manual operation includes an operation of rotating the intermediate transfer body. 21. An intermediate transfer member cleaning means capable of contacting and releasing the intermediate transfer member, wherein when the intermediate transfer member is rotated by the manual operation, the intermediate transfer member cleaning means is released from contact. The intermediate transfer body cleaning unit is brought into contact with the intermediate transfer body when the intermediate transfer body is driven for a predetermined time to discharge the transfer material out of the double-sided image forming apparatus.
21. The double-sided image forming apparatus according to any one of 20. 22. The two-sided recording medium according to claim 18, wherein the manual operation includes an operation of driving a transfer material supply unit that supplies the transfer material to the intermediate transfer body. Image forming device. 23. The method according to claim 18, wherein the manual operation includes an operation of moving the secondary transfer unit.
3. The double-sided image forming apparatus according to any one of 2. 24. The method according to claim 18, wherein the manual operation includes an operation of moving a transfer material separation assisting unit that assists separation of the transfer material when the transfer material is separated from the intermediate transfer body. 24. The double-sided image forming apparatus according to any one of claims 23 to 23. 25. A first image carrier for carrying the toner image formed by the first toner image forming means, and a second image carrier for carrying the toner image formed by the second toner image forming means. A belt-shaped intermediate transfer body that transfers the toner image on the first image carrier, carries the transferred toner image, and supports and conveys a transfer material; and the first image carrier. A first primary transfer unit for transferring the upper toner image to the intermediate transfer body, a second primary transfer unit for transferring the toner image on the second image carrier to the surface of the transfer material, A double-sided image forming apparatus, comprising: a secondary transfer unit that re-transfers a toner image on the intermediate transfer member to the back surface of the transfer material; and a fixing unit that fixes the toner image on the transfer material. The transfer by the intermediate transfer member when forming an image on In the event that an accident occurs in which the conveyance of the image is not normally performed, the driving of the first and second image carriers, the driving of the intermediate transfer member, and the toner image by the first and second toner image forming units are performed. Forming the first and the second 1
A stop operation for immediately stopping the transfer of the toner image by the next transfer unit and the retransfer of the toner image by the secondary transfer unit is performed. After the stop operation, the transfer material that is not normally conveyed is removed from the intermediate material. A manual operation for returning the transfer material to the transfer material transport surface on the intermediate transfer body when the transfer material is normally transported by the transfer body; After returning to the transport surface, the second image carrier, the intermediate transfer member, and the fixing unit are driven for a predetermined time, and the transfer material is discharged out of the double-sided image forming apparatus. Forming equipment. 26. The manual operation, comprising: separating the second image bearing member and the intermediate transfer member from each other;
26. The double-sided image forming apparatus according to claim 25, further comprising an operation of contacting the image carrier with the intermediate transfer member. 27. The double-sided image forming apparatus according to claim 26, wherein the manual operation includes an operation of rotating the intermediate transfer member. 28. The double-sided printing apparatus according to claim 25, wherein the manual operation includes an operation of driving a transfer material supply unit that supplies the transfer material to the intermediate transfer body. Image forming device. 29. The method according to claim 25, wherein the manual operation includes an operation of moving the secondary transfer unit.
9. The double-sided image forming apparatus according to any one of 8. 30. The method according to claim 25, wherein the manual operation includes an operation of moving a transfer material separation assisting unit that assists separation of the transfer material when the transfer material is separated from the intermediate transfer body. 30. The double-sided image forming apparatus according to any one of items 29 to 29.