JPH1152803A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a removed toner quantity by limiting the cleaned regions of a photoreceptor belt and an intermediate transfer belt for holding plural images, after a recovery from a jam is made. SOLUTION: When a transfer paper is jammed while the toner images of plural screens after being primarily transferred to the intermediate transfer belt are transferred to a transfer paper, and a recovery operation from the jam is started, an untransferred image discriminating part 73 judges whether an image not transferred to the transfer paper exists or not out of the toner images after being transferred to the intermediate transfer belt with control information from a transfer control part 72. A cleaning region selecting part 74 sets the cleaned region of the intermediate transfer belt, with the result of the judgment, to transmit the set cleaned region to the transfer control part 72. This part 72 cleans the region except the remaining region of the toner images not transferred to the transfer paper, of the intermediate transfer belt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus capable of simultaneously forming an image on a plurality of surfaces with a digital color copying machine, a printer, or the like. The present invention relates to improvement of image forming efficiency after transfer paper jam occurs.

[0002]

2. Description of the Related Art In order to improve the efficiency of forming a color image in an image forming apparatus for forming a multicolor image of a document read by a document reading device or image information sent from a host device, for example, Japanese Patent Application Laid-Open No. 4-175774 is disclosed. As shown, a two-color image having a reference image size was formed on a photoreceptor belt having a reference image size, for example, a photoreceptor belt having a length of twice or more the A4 size, and formed on the photoreceptor belt. Transferring the toner image on the screen to a transfer paper to be sequentially fed, or transferring a plurality of screens of the toner image formed on the photoreceptor to an intermediate transfer belt having a length twice or more of a reference image size; Are transferred to transfer paper which is sequentially fed.

When the toner images of a plurality of screens are held by the photoreceptor belt or the intermediate transfer belt as described above, and the held toner images are transferred onto the transfer paper, the image forming process is interrupted if a jam occurs on the transfer paper. Then, at the time of recovery after the jam processing, all the image surfaces of the photosensitive belt and the intermediate transfer belt are cleaned, and then the image is formed again.

[0004]

As described above, the toner images on a plurality of screens are held by the photosensitive belt or the intermediate transfer belt.
If the transfer paper jams while transferring the retained toner image to the transfer paper and the entire image surface of the photoreceptor belt and the intermediate transfer belt is cleaned at the time of recovery after the jam processing, the transfer is not performed yet. Since the remaining image surface is cleaned, the amount of toner to be removed by the cleaning device increases, the amount of toner consumption increases, and the life of the cleaning device is shortened. In addition, since it is necessary to form an image that has not been transferred and remains again after the jam recovery, it takes time until the image is transferred to transfer paper.

The present invention has been made to solve such a disadvantage, and reduces the amount of toner to be removed by limiting a cleaning area of a photosensitive belt or an intermediate transfer belt holding a plurality of images after jam recovery. It is another object of the present invention to provide an image forming apparatus capable of rapidly transferring the image to a transfer sheet.

[0006]

An image forming apparatus according to the present invention has an image holding means capable of holding a plurality of screens of a toner image having a reference image size at the same time. In an image forming apparatus for transferring to a transfer material, when a transfer paper jam occurs when a toner image held in an image holding unit is transferred to transfer paper, the transfer operation is interrupted, and a plurality of images held in the image holding unit are stopped. Judge whether there is an image that has not been transferred to the transfer paper, clean the area that has been transferred to the transfer paper of the image holding means at the time of recovery after jam recovery, and clean the area where the image that has not been transferred to the transfer paper It is characterized in that an image is held without being stored. After the recovery from the jam processing, the image held in the image holding means is transferred to a transfer sheet.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An image forming apparatus according to the present invention has an image forming unit, a primary transfer unit, a secondary transfer unit, a fixing unit, and a paper discharge unit. The image forming unit forms an electrostatic latent image on a photoreceptor by a laser beam from an image writing unit, and visualizes the formed electrostatic latent image by a color developing unit to form a toner image. The primary transfer unit includes an intermediate transfer belt wound around a plurality of tension rollers and a primary transfer unit.
It has a reference position sensor for reading reference marks on the next transfer portion and the intermediate transfer belt, and a cleaning portion, and primarily transfers the toner image formed on the photoreceptor to the intermediate transfer belt. The intermediate transfer belt has a reference image size, for example, twice or more the length of the A4 size, and at the same time, the A4 size which is the reference size.
A toner image of two sizes can be transferred. The secondary transfer unit secondarily transfers the toner image transferred to the intermediate transfer belt to transfer paper.

The control unit is connected to a document reading unit and a host interface, processes the image information of the read document and image information sent from the host device, and manages the operation of the entire apparatus, and a central control unit. The unit includes a transfer control unit that controls the operation of the unit, the primary transfer unit and the secondary transfer unit, an untransferred image determination unit, and a cleaning area selection unit.

When a plurality of screens of toner images primary-transferred onto the intermediate transfer belt are being transferred onto a transfer sheet and a transfer sheet jam occurs, the transfer control unit controls the image forming unit, the primary transfer unit, and the like. The operation of the secondary transfer unit is immediately stopped, and a transfer paper jam is displayed on the operation panel. When the operator confirms this display and removes the jammed transfer paper and starts the jam recovery operation, the untransferred image determination unit transfers the toner image onto the transfer paper with the toner image transferred to the intermediate transfer belt by the control information from the transfer control unit. It is determined whether there is an image that has not been performed. Based on the result of the judgment by the untransferred image discriminating section, the cleaning area selecting section determines the area to be cleaned of the intermediate transfer belt at the time of recovery after the jam processing and sends it to the transfer control section. When the cleaning area is sent from the cleaning area selecting section, the transfer control section drives the primary transfer unit to set a predetermined cleaning area of the intermediate transfer belt.
That is, the area other than the area where the toner image not transferred to the transfer paper remains is cleaned. When the cleaning of the predetermined area of the intermediate transfer belt is completed, the toner images held on the intermediate transfer belt are sequentially transferred to the transfer paper fed, fixed, and discharged. As described above, only the area of the intermediate transfer belt that does not hold the toner image is cleaned at the time of the jam recovery when the transfer paper jam occurs.
The amount of toner removed by the cleaning unit can be reduced. Further, since the toner image remaining on the intermediate transfer belt is immediately transferred to the transfer paper, an image can be quickly formed on the transfer paper.

[0010]

FIG. 1 is a block diagram of an image forming apparatus according to an embodiment of the present invention. As shown in the figure, the image forming apparatus has an image forming unit 1, a primary transfer unit 2, a secondary transfer unit 3, a fixing unit 4, and a paper discharge unit 5. The image forming unit 1 includes a charging charger 2 disposed around a photoconductor 11, an image writing unit 13, and a rotary or fixed type including black (K), cyan (C), magenta (M), and yellow (Y). And an electrostatic latent image formed on the photoreceptor 11 by a laser beam from the image writing unit 13, and the formed electrostatic latent image is colored. The toner image is formed by visualization in the developing unit 14. The density sensor 16 detects the density of a specific pattern drawn on the photoreceptor 11 on which the toner image has been formed, and checks whether the toner image is formed at an appropriate density.

The primary transfer unit 2 includes an intermediate transfer belt 21
, Primary transfer unit 22, plural tension rollers 23, secondary transfer roller 24, and reference mark 27 of intermediate transfer belt 21
Position sensor 25 and cleaning unit 26 for reading
And the primary transfer of the toner image formed on the photoconductor 11 to the intermediate transfer belt 21. The intermediate transfer belt 21 has a reference image size, for example, twice or more the length of an A4 size, and can simultaneously transfer toner images of two A4 sizes as a reference size. As shown in the figure, the reference mark 27 is provided in the non-image portion. The intermediate transfer belt 21 is separated from the surface of the photoconductor 11 by a contact / separation mechanism (not shown) except when the toner image on the photoconductor 11 is primarily transferred, and is pressed against the surface of the photoconductor 11 only when the toner image is primarily transferred. You. The secondary transfer unit 3 secondarily transfers the toner image transferred to the intermediate transfer belt 21 to the transfer paper 6.

As shown in the block diagram of FIG. 3, a controller 7 of the image forming apparatus is connected to a document reading unit 8 and a host interface 9 to read image information of a read document and an image sent from the host device. A central control unit 71 for processing information to manage the operation of the entire apparatus; a transfer control unit 72 for controlling the operations of the image forming unit 1, the primary transfer unit 2 and the secondary transfer unit 3; And a cleaning area selection unit 74. The untransferred image discriminating unit 73 is provided when the transfer paper jam occurs.
Based on the control information from 2, it is determined whether there is an image that has not been secondarily transferred to the transfer paper 6 among the toner images transferred to the intermediate transfer belt 21. The cleaning area selection unit 74 determines an area to be cleaned of the intermediate transfer belt 21 at the time of recovery after the jam processing based on the determination result of the untransferred image determination unit 73.

When a document read by the image forming apparatus configured as described above or image information sent from the host device is sent and an image forming cycle is started, image data for forming an image is one or more colors. Is determined by a command.
When the image to be formed is of one color, it is not necessary to detect the reference mark 27 of the intermediate transfer belt 21 of the primary transfer unit 2, so that the image is sequentially formed on the photoconductor 11 of the image forming unit 1 as shown in FIG. The toner images 10a to 10c are primarily transferred to the intermediate transfer belt 21 regardless of the position of the reference mark 27. The secondary transfer unit 3 secondarily transfers the toner image to the transfer paper 6 sequentially fed according to the leading ends of the toner images 10a to 10c transferred to the intermediate transfer belt 21, and the fixing unit 4 transfers to the transfer paper 6. The applied toner image is heated and pressed to be fixed. The paper discharge unit 5 discharges the transfer paper 6 on which an image is formed to a paper discharge tray. The toner remaining on the intermediate transfer belt 21 is collected by the cleaning unit 28.

When the image to be formed has two or more colors, the toner image formed on the photoreceptor 11 is
The reference mark 27 on the intermediate transfer belt 21 is used to superimpose each color image so that there is no color shift at the time of next transfer.
Is detected by the reference position sensor 25, and as shown in FIG.
Is primarily transferred to the intermediate transfer belt 21. This primary transfer is repeated for each color. That is, when forming a two-color image, the intermediate transfer belt 21 is used.
Is rotated twice to form a full-color image, the intermediate transfer belt 21 is rotated four times, and the toner image 10 formed on the photoreceptor 11 is rotated at each rotation based on a mark detection signal. And the images of the respective colors are superimposed without displacement. After the toner image 10 of a predetermined color is transferred to the intermediate transfer belt 21, the toner image 10 is secondarily transferred to the transfer paper 6 fed according to the leading end of the toner image 10 transferred to the intermediate transfer belt 21 and fixed. The unit 4 fixes the toner image transferred to the transfer paper 6 by heating and pressing.

A process when the toner images of a plurality of screens primarily transferred to the intermediate transfer belt 21 are secondarily transferred to the transfer paper 6 will be described with reference to a flowchart of FIG.

The toner images of a plurality of screens are primarily transferred to the intermediate transfer belt 21, the transfer paper 6 is fed, and the secondary transfer is started (step S1). If the transfer paper 6 does not jam (step S1). S2) The toner images held on the intermediate transfer belt 21 are secondarily transferred onto the sequentially fed transfer paper 6, fixed, and then discharged (step S3). This transfer paper 6
If the paper jam occurs on the transfer paper 6 while the paper is being fed or the secondary transfer or the fixing and the discharge are performed on the transfer paper 6 (steps S4 and S2), the transfer control unit 72 makes the primary contact with the image forming unit 1. The operations of the transfer unit 2 and the secondary transfer unit 3 are immediately stopped, and a transfer paper jam is displayed on an operation panel (not shown) (step S5). When the operator who confirms this display opens the cover of the image forming apparatus, removes the jammed transfer paper 6 and closes the cover, the jam recovery operation starts (step S6). When the jam recovery operation starts, the untransferred image determination unit 73 determines whether there is an image that has not been transferred to the transfer paper 6 among the toner images transferred to the intermediate transfer belt 21 based on the control information from the transfer control unit 72. (Step S7). For example, as shown in FIG. 4, toner images 10a to 10c for three surfaces are held on the intermediate transfer belt 21, and the toner image 10a for the first surface is transferred to the transfer paper 6 to transfer the toner image 10b for the second surface. When a jam occurs while the next transfer sheet 6 is being fed, the untransferred image determination unit 73 determines that the second-side toner image 10b and the third-side toner image 10c remain on the intermediate transfer belt 21. . The cleaning area selection unit 7 according to the determination result of the untransferred image determination unit 73
Reference numeral 4 designates an area to be cleaned of the intermediate transfer belt 21 at the time of recovery after the jam processing and sends it to the transfer control unit 72 (step S8). For example, when the untransferred image determination unit 73 determines that the second surface toner image 10b and the third surface toner image 10c remain on the intermediate transfer belt 21, the first surface toner image 10a of the intermediate transfer belt 21 is formed. Only the cleaned area is defined as a cleaning area. Transfer control unit 7
When the cleaning area is sent from the cleaning area selecting unit 74, the primary transfer unit 2 is driven to leave a predetermined cleaning area of the intermediate transfer belt 21, for example, the toner image 10b on the second surface and the toner image 10c on the third surface. In this case, only the area where the first-side toner image 10 a is formed is cleaned by the cleaning unit 26, and the second-side toner image 10 b and the third-side toner image 1
0c is held (step S9). After the cleaning of the predetermined area of the intermediate transfer belt 21 is completed, the image forming unit 1, the primary transfer unit 2, and the secondary transfer unit 3 are restarted (Steps S10 and S11), and are held on the intermediate transfer belt 21. The transferred toner image, for example, the toner image 10b on the second side and the toner image 10c on the third side are transferred to the sequentially supplied transfer paper 6, fixed and discharged (step S1).
2) The image forming process is started again (step S13).

As described above, only the area of the intermediate transfer belt 21 that does not hold the toner image is cleaned at the time of jam recovery when the paper jam occurs, so that the amount of toner removed by the cleaning unit 26 is reduced. As a result, the consumption of the toner can be reduced, and the life of the cleaning unit 26 can be prolonged. Further, since the toner image remaining on the intermediate transfer belt 21 is immediately transferred to the transfer paper 6, an image can be quickly formed on the transfer paper 6.

When the untransferred image determining section 73 determines that all the toner images transferred to the intermediate transfer belt 21 have been transferred to the transfer paper 6 (step S7), the cleaning area selecting section 74 performs recovery after the jam processing. At this time, it is determined that all areas of the intermediate transfer belt 21 are to be cleaned, and the transfer control unit 72 cleans all areas of the intermediate transfer belt 21 at the time of jam recovery (step S14).

Although the above embodiment has been described with reference to the case where a plurality of screens of toner images are held on the intermediate transfer belt 21, the same can be applied to the case where a plurality of screens of toner images are held on the photosensitive belt.

[0020]

As described above, the present invention cleans only an area of the image holding means, such as an intermediate transfer belt and a photoreceptor belt, which does not hold a toner image during jam recovery when a transfer paper jam occurs. Therefore, the amount of toner to be removed can be reduced, the amount of consumed toner can be reduced, and the life of the cleaning device can be prolonged.

Further, since the toner image remaining on the image holding means is immediately transferred to the transfer paper at the time of the jam recovery, the image can be quickly formed on the transfer paper, and the image forming time can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a reference mark of the intermediate transfer belt.

FIG. 3 is a block diagram illustrating a configuration of a control unit according to the embodiment.

FIG. 4 is an explanatory diagram illustrating a one-color toner image transferred to an intermediate transfer belt.

FIG. 5 is an explanatory diagram illustrating a multicolor toner image transferred to an intermediate transfer belt.

FIG. 6 is a flowchart showing the operation of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming unit 2 Primary transfer unit 3 Secondary transfer unit 11 Photoconductor 21 Intermediate transfer belt 7 Control part 71 Central control part 72 Transfer control part 73 Untransferred image discriminating part 74 Cleaning area selecting part

Claims (2)

[Claims] 1. An image forming apparatus, comprising: an image holding unit capable of simultaneously holding a toner image of a reference image size for a plurality of surfaces; and transferring the toner image held by the image holding unit to a transfer material. When the transfer paper jam occurs when transferring the toner image held in the transfer paper to the transfer paper, the transfer operation is interrupted, and there is an image which is not transferred to the transfer paper among the plurality of images held in the image holding unit. Is determined, the area transferred to the transfer paper of the image holding means is cleaned at the time of recovery after the jam processing, and the image is held without cleaning the area where the image is not transferred to the transfer paper. Image forming device. 2. The image forming apparatus according to claim 1, wherein the image held in the image holding means is transferred to a transfer sheet after the recovery from the jam processing.