JPH11242420A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance image forming efficiency by reducing the number of scanning time. SOLUTION: When a first original is supplied to an original read unit 9, it is scanned by using the unit 9 by a central control part 30 in the case that it is equal to or under A4-size that two sheets of first originals can be simultaneously transferred on an intermediate transfer belt and the image of the first original is formed by the color image of two or more colors. Then, the read color image is stored in an image storage means 31. When the second original is supplied to the unit 9 and it is equal to or under A4-size and color, the image of the first original and the color toner image of the image of the original are transferred on the intermediate transfer belt by using the image of the first original stored in the storage means 32 and the read image of the second original whenever the second original is scanned.

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 forming images on two surfaces simultaneously with a digital color copying machine, a printer, or the like, and more particularly to an improvement in image forming efficiency.

[0002]

2. Description of the Related Art As shown in, for example, Japanese Patent Laid-Open No. 4-175774, a toner image of an original read by an original reading device and an image of image information sent from a host device are simultaneously printed.
2. Description of the Related Art An image forming apparatus has been used in which image formation efficiency is improved by forming areas. This image forming apparatus, as shown in FIG.
An image forming unit 1, a primary transfer unit 2, a secondary transfer unit 3, a paper feed unit 4 and a fixing unit 5 are provided. The image forming unit 1 includes a charging charger 12 and an image writing unit 13 disposed around a photoreceptor 11, and a rotary or fixed type including black (K), cyan (C), magenta (M), and yellow (Y). And an electrostatic latent image is formed on the photoreceptor 11 by the laser beam from the image writing unit 13, and the formed electrostatic latent image is formed by the color developing unit 14. Visualize to form a toner image. The primary transfer unit 2 includes an intermediate transfer belt 21, a primary transfer unit 22, and a plurality of tension rollers 2.
It has a third transfer roller 24, a reference position sensor 25, and a cleaning unit 26, and primary-transfers 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 as long as the A4 size, and is capable of simultaneously transferring toner images of two surfaces. As shown in FIG. Two reference marks 27a and 27b are provided at a fixed interval in the image portion. This intermediate transfer belt 21 is
Except during the primary transfer of the upper toner image, the toner image is separated from the surface of the photoconductor 11 by a contact / separation mechanism (not shown), and is pressed against the surface of the photoconductor 11 only during the primary transfer of the toner. The secondary transfer unit 3 secondarily transfers the toner image transferred to the intermediate transfer belt 21 to the transfer paper 6. The paper feed unit 4 has, for example, four paper feed trays 41a to 41d.

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 one color, since it is not necessary to detect the reference marks 27a and 27b of the intermediate transfer belt 21 of the primary transfer unit 2, the toner image formed on the photoreceptor 11 is primary-transferred to the intermediate transfer belt 21. Transcribe. Secondary transfer unit 3
The transfer paper 6 fed from the paper feed tray 41a, for example, matches the leading end of the toner image transferred to the intermediate transfer belt 21.
The fixing unit 5 fixes the toner image transferred to the transfer paper 6 by heating and pressing. The toner remaining on the intermediate transfer belt 21 is
Collect at 6.

When an 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 the toner image formed on the photoconductor 11 is primarily transferred to the intermediate transfer belt 21 based on the mark detection signal. This primary transfer is repeated for each color. That is, when forming a two-color image, the intermediate transfer belt 21 is rotated twice, and when a full-color image is formed, the intermediate transfer belt 21 is rotated four times. The primary transfer of the toner image formed on the photoreceptor 11 to the intermediate transfer belt 21 is performed, and the images of the respective colors are superimposed without displacement. When the toner image of a predetermined color is transferred to the intermediate transfer belt 21, the intermediate transfer belt 2
The toner image is secondarily transferred to a transfer sheet 6 fed according to the leading end of the toner image transferred to the transfer sheet 1, and the fixing unit 5 fixes the toner image transferred to the transfer sheet 6 by heating and pressing.

When a toner image of a reference size smaller than the distance between the reference marks 27a and 27b, for example, an A4 size image, is simultaneously transferred to the intermediate transfer belt 21 for two surfaces,
As shown in FIG. 6, the toner image 7a for one surface is transferred to the intermediate transfer belt 21 with reference to the reference mark 27a, and then the toner image 7b for two surfaces is transferred to the intermediate transfer belt 21 with reference to the reference mark 27b. And the toner images 7a and 7b transferred to the intermediate transfer belt 21 are secondarily transferred onto transfer paper 6 continuously fed from a paper feed tray 41a on which A4-size transfer paper 6 is set.

[0006]

As described above, when a two-sided toner image of a full-color image of an A4 size document is transferred to an intermediate transfer belt, the first document and the second document are transferred by an automatic document feeder. The document had to be sent four times to the document reading device and collected, and each document had to be scanned four times, which required a lot of time to scan the document. SUMMARY OF THE INVENTION It is an object of the present invention to improve such disadvantages and to obtain an image forming apparatus capable of improving image forming efficiency.

[0007]

An image forming apparatus according to the present invention has an intermediate transfer belt capable of simultaneously transferring toner images of a reference image size formed on a photosensitive member for a plurality of surfaces. Transfer the transferred toner image to the transfer material 2
In the image forming apparatus that performs the next transfer, when the number of copies on the original sent to the original reading unit is two or more, or when a color image of two or more colors is formed, the image read by the original reading unit is copied. It is characterized by being stored in an image storage means.

In the above image forming apparatus, when the number of copies on the original is two or more, or when a color image of two or more colors is formed, the image read by scanning the first original once is stored in an image storage. Means for transmitting the second document to the document reading means, and forming a first color toner image of the first document and the second document when the first scanning of the second document is completed. The image is transferred to the transfer belt, and after the second sheet or after the second color, the image of the first document is read from the image storage means, and only the second document is scanned. Further, when the number of copies of the first document is one or one color image, the read image of the first document is not stored in the image storage means, and when the number of copies of the document is two or more, or 2
When forming a color image of more than one color,
The image read by the second scanning is stored in the image storage means, and the second and subsequent colors of the second document are read out from the image storage means.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An image forming apparatus according to the present invention includes an automatic document feeder, a document reading unit, an image forming unit 1, a primary transfer unit, a secondary transfer unit, a paper feed unit, and a fixing 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, a primary transfer unit, a secondary transfer roller, a reference position sensor, and a cleaning unit, and transfers a toner image formed on a photoconductor to the intermediate transfer belt. 1 in
Next transfer. The intermediate transfer belt has a length equal to or more than twice as large as an A4 size, which is one round, and is capable of simultaneously transferring toner images for two surfaces. The image portion has two fiducial marks at regular intervals. The secondary transfer unit secondarily transfers the toner image transferred to the intermediate transfer belt to transfer paper. The control unit of the image forming apparatus has a central control unit that processes the image information of the read original to manage the operation of the entire apparatus, and an image storage unit that stores a full-color image of one surface of the read original.

In this image forming apparatus, when the first original is fed from the automatic original feeder to the original reading unit, the central control unit determines that the first original is not larger than A4 size which can simultaneously transfer two first originals to the intermediate transfer belt. When the image of the first document is formed of two or more color images, the first document is scanned by the document reading unit, the read color image is stored in the image storage means, and the first document is read. The second document is discharged from the reading unit and fed to the document reading unit. When the second document is fed to the document reading unit and the second document is smaller than A4 size, the central controller scans the second document and reads the first document image stored in the image storage means. A first color toner image is continuously formed on the photoreceptor with the second document image, and the first document image and the first color toner image of the document image are transferred to the intermediate transfer belt. If the second document is color, the second document is scanned a predetermined number of times to read the second document image, and the first document image stored in the image storage means and the read second document image are intermediated. The first document image and the color toner image of the document image are transferred to the transfer belt. The first document image and the color toner image of the document image formed on the intermediate transfer belt are respectively transferred to a transfer sheet, fixed, and discharged.

[0011]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. The image forming unit 1, the primary transfer unit 2, the secondary transfer unit 3, the paper feed unit 4, and the fixing unit 5 of the image forming apparatus of this embodiment have exactly the same configuration as that shown in FIG. The control unit 30 of the image forming apparatus is connected to the host interface 8, the document reading unit 9, the automatic document feeder 10 and the operation display unit 50, and processes the image information sent from the host device and the image information of the read document. Central control unit 31 for managing the operation of the entire apparatus
And an image storage means 32 for storing a full-color image for one surface of the read original. Automatic document feeder 10
As shown in FIG. 2, a document placed on the document glass 101 of the document reading unit 9 is automatically fed onto the contact glass 91 on the document table 101, and the read document is placed in a document stacking section. The paper is discharged to 102. As shown in FIG. 3, the operation display unit 50 includes a copy start button 51, a preheating / mode clear key 52 used when setting the preheating mode and initializing settings such as the copy mode, and for interrupting the copying operation and the number of copies. And a numeric keypad 54 for setting the number of copies, etc., and a liquid crystal display 55 for displaying the set number of copies and the number of copies to be completed.

The operation of the image forming apparatus configured as described above will be described with reference to the flowchart of FIG. When a document is set on the automatic document feeder 10 and the copy start button 51 of the operation display unit 50 is pressed, the first document is fed from the automatic document feeder 10 to the document reading unit 9. The central control unit 31 checks the size of the fed first document, and determines whether the first document is smaller than the A4 size that allows two sheets to be simultaneously transferred onto the intermediate transfer belt 21 (step S1). Is larger than A4 size, for example, A3 size, a normal operation for forming an image is performed for each document, the toner image is transferred to the intermediate transfer belt 21, and the toner image formed on the intermediate transfer belt 21 is transferred to the transfer paper 5. (Step S2). When the first document is smaller than the A4 size that can simultaneously transfer two sheets to the intermediate transfer belt 21, the central control unit 31 determines whether the image of the first document is formed of two or more color images (step S3). ), When the image of the first document is formed by two or more color images,
The original is scanned by the original reading unit 9, the read color image is stored in the image storage unit 32, the first original is discharged from the original reading unit 9, and the second original is fed to the original reading unit 9. (Step S4). When the second document is fed to the document reading unit 9, the central control unit 3
1 checks whether the second document is smaller than A4 size (step S5). If the second document is smaller than A4 size,
The second document is scanned (step S6), and a first color toner image is continuously formed on the photoconductor 11 by the first document image stored in the image storage unit 32 and the read second document image. The first document image and the toner image of the first color of the document image are transferred to the intermediate transfer belt 21 (step S7). If the second document is full color, the second document is scanned a predetermined number of times to read the second document image, and the first document image stored in the image storage means 32 and the read second document image are used. The first document image and the full-color toner image of the document image are transferred to the intermediate transfer belt 21 (steps S8 and S8).
7). The first original image and the full-color toner image of the original image formed on the intermediate transfer belt 21 are respectively transferred to the transfer paper 6, fixed and discharged. Also, if the second document is A
If the size is equal to or larger than four, after the transfer of the image of the first document is completed, the image is transferred to the transfer paper 6 by a normal operation of scanning the second document (step S2).

In this way, when the first document and the second document are of A4 size which can transfer two sheets to the intermediate transfer belt 21, an image obtained by reading the first document is stored in the image storage means. The number of scans of the original document is reduced to only one, and the number of scans when simultaneously transferring two toner images to the intermediate transfer belt can be reduced, so that a full-color image can be obtained quickly.

When the image formed by the first document is a monochrome image (step S3), the central control unit 31 checks the number of the first document set on the operation display unit 50 (step S9). When forming a plurality of first originals, the first original is scanned by the original reading unit 9, the read image is stored in the image storage unit 32, and the first original is discharged from the original reading unit 9. Then, the second document is fed to the document reading unit 9 (step S4). When the second document is fed to the document reading unit 9 and the second document is smaller than A4 size, the second document is scanned in the same manner as described above (steps S5 and S6) and stored in the image storage unit 32. A first color toner image is continuously formed on the photoreceptor 11 with the read first document image and the read second document image, and the intermediate transfer belt 2
Then, the first document image and the toner image of the first color of the document image are transferred to Step 1 (Step S7). And the intermediate transfer belt 21
The toner image of the first document formed on the first document is transferred to the transfer paper 6, and when the second document is color, the second document is scanned a predetermined number of times to read the second document image. The toner image of the first document image and the full-color toner image of the second document image are transferred to the intermediate transfer belt 21 using the first document image stored in the image storage unit 32 and the read second document image (step). S8, S7).

The image formed by the first document is a black and white image (step S3). When one first document is formed (step S9), the first document is scanned by the document reading unit 9. The read image of the first document is temporarily stored in the memory of the document reading unit 9, the first document is discharged from the document reading unit 9, and the second document is fed to the document reading unit 9 (step S10). ). When the second document is fed to the document reading unit 9 and the second document is smaller than A4 size and the image formed by the second document is two colors or more (steps S11 and S12), the central controller 31 Scans the second document and stores the read color image in the image storage means 32 (step S13). Then, toner images of the image of the first document and the image of the second document are sequentially formed on the photoconductor 11, and the formed toner images are sequentially transferred to the intermediate transfer belt 21 (step S14). If the second document is A4 size or smaller and the image formed by the second document is a black and white image (steps S11 and S12), the image of the first document is scanned at the time when the second document is scanned. Then, a toner image of the image of the second document is sequentially formed on the photoconductor 11, and the formed toner image is sequentially transferred to the intermediate transfer belt 21 (steps S15 and S14).

[0016]

According to the present invention, as described above, when the number of copies on the original sent to the original reading means is two or more or when a color image of two or more colors is formed,
Since the image read by the document reading means is stored in the image storage means, the number of times of scanning of the document can be reduced, and when the document is a copy using toner, the toner is heated by the heat of a plurality of scans. It is possible to prevent the melted original from adhering to the original reading means or being jammed in the automatic original feeder.

An image read by scanning the first document once is stored in an image storage means, and when the first scanning of the second document is completed, the first document and the second document are scanned. The first color toner image is formed and transferred to the intermediate transfer belt. After the second sheet or the second color or later, the image of the first document is read out from the image storage means, and only the second document is scanned.
When the setting number for the first document is one or one color image,
The image of the read first document is not stored in the image storage means, and the image read by scanning the second document having a set number of 2 or more or two colors or more once is stored in the image storage means, and the second image is stored in the image storage means. By reading out the second and subsequent colors of the image of the original from the image storage means, the number of scans when simultaneously transferring a plurality of surfaces to the intermediate transfer belt can be reduced, and the image forming efficiency when forming a color image can be improved. Can be done.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a configuration diagram of an automatic document feeder.

FIG. 3 is a layout diagram of an operation display unit.

FIG. 4 is a flowchart showing the operation of the embodiment.

FIG. 5 is a configuration diagram of an image forming apparatus.

FIG. 6 is a layout diagram of reference marks on the intermediate transfer belt.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming unit 2 Primary transfer unit 3 Secondary transfer unit 4 Paper feed unit 5 Fixing unit 9 Document reading unit 10 Automatic document feeder 11 Photoconductor 21 Intermediate transfer belt 30 Control unit 31 Central control unit 32 Image storage means 50 Operation Display

Claims (3)

[Claims] An intermediate transfer belt capable of simultaneously transferring toner images of a reference image size formed on a photoreceptor for a plurality of surfaces is provided, and the toner image transferred to the intermediate transfer belt is secondarily transferred to a transfer material. In the image forming apparatus, when the number of copies on the original sent to the original reading unit is two or more, or when a color image of two or more colors is formed, the image read by the original reading unit is stored in the image storage unit. An image forming apparatus comprising: 2. The image forming apparatus according to claim 1, wherein
When the number of copies on the original is two or more, or when forming a color image of two or more colors, the first original is scanned once and the read image is stored in the image storage means, and the second original is stored. To the document reading means, and when the first scanning of the second document is completed, the first color toner images of the first document and the second document are formed and transferred to the intermediate transfer belt. An image forming apparatus for reading an image of a first document from an image storage unit and scanning only a second document after the second color. 3. The image forming apparatus according to claim 1, wherein
When the setting number for the first document is one or one color image,
The second document is scanned once when the read image of the first document is not stored in the image storage means and the number of copies on the document is two or more or when a color image of two or more colors is formed. The read image is stored in the image storage means, and the second
An image forming apparatus for reading out the image of the second color or later of the original from the image storage means.