JPH1098593A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of double side recording in which print productivity is improved with a simple configuration, high speed printing is attained and occurrence of recording paper carrying trouble is minimized. SOLUTION: The device is provided with a storage means 30 storing image data and a plurality of image forming sections A, B forming an image onto recording paper based on the image data stored in the storage means 30. In the case of forming an image onto one side of a plurality of recording paper, the same image data or different image data in the storage means 30 are fed to a plurality of the image forming sections A, B, and a plurality of the image forming sections A, B form the image almost at the same time. In the case of forming an image on both sides of recording paper, image data of one side in the front/rear sides of the original stored in the storage means 30 are fed to one side of the recording paper by the image forming section A and the image data of the other side are fed to the image forming section B, which forms the image on the other side of the recording paper whose one side is formed with the image.

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 for forming an image on both sides of a recording sheet, and more particularly, to a double-sided or single-sided recording sheet by a plurality of image forming units based on image data stored in a storage means. The present invention relates to an image forming apparatus for forming an image on a paper.

[0002]

2. Description of the Related Art In a conventional double-sided image forming apparatus, a recording sheet conveyed from a sheet feeding section is sent to an image forming section to form an image on one side, and then the recording sheet is reversed by a reversing mechanism section.
In general, the sheet is sent to the original image forming section again to form an image on both sides.

In this method, only one image forming unit is used, and if the productivity is to be improved on one side or both sides, the processing speed (process speed) of the image forming unit must be increased. There was a limit.

On the other hand, Japanese Unexamined Patent Publication No. 57-102383 discloses a method for improving productivity by providing a plurality of image forming units, in which the same image data input from an input means is recorded on one side by a plurality of recording units. The configuration for each recording is described.

In the recording apparatus disclosed in Japanese Patent Application Laid-Open No. 59-90868, a conveyance path is provided to connect two recording apparatuses one on top of the other and to connect them, and a recording apparatus for the front side and a recording apparatus for the back side are used. This is to perform double-sided recording.

Some of these known examples consider high productivity only on one side and high productivity only on both sides. However, one image forming apparatus has high productivity even on one side and both sides. The technology to achieve was not considered or was of low productivity.

[0007]

In a conventional electrophotographic image forming apparatus such as a copying machine or a laser printer, when performing high-speed printing, the processing speed of the image forming section is generally increased to cope with the problem. there were. However, increasing the processing speed may make it difficult to set conditions for the image forming process. That is, there is the following problem.

(1) Enlargement of the charging electrode, (2) Enhancement of sensitivity of the photoreceptor, (3) Decrease in durability due to enlargement and speeding up of the developing device, Decrease in developability due to decrease in development nip time, Various problems such as scattering of toner and carrier due to high speed, (4)
Due to the increase in size of the transfer electrode, the decrease in the separability of the recording paper, and (5) the decrease in the fixability due to the decrease in the fixing nip time, the speed of a single image forming unit is naturally limited for the above reasons. was there. On the other hand, in the case of achieving high productivity in a plurality of image forming units, high productivity for both sides is not considered, and efficient two-sided copying cannot be obtained.

The present invention eliminates the above-mentioned drawbacks, improves print productivity and achieves high-speed printing during single-sided printing and double-sided printing with a simple configuration, and eliminates the occurrence of recording paper transport problems. It is an object of the present invention to provide a highly reliable image forming apparatus capable of double-sided recording that can be minimized.

[0010]

According to an aspect of the present invention, there is provided an image forming apparatus, comprising: a storage unit for storing image data; and a plurality of units for forming an image on a recording sheet based on the image data stored in the storage unit. In the image forming apparatus having an image forming unit, when performing image formation on one side of a plurality of recording sheets, sending the same image data or different image data in the storage unit to the plurality of image forming units, When image formation is performed by the plurality of image forming units at substantially the same time and image formation is performed on both sides of the recording paper, the image data of one of the front and back surfaces of the document stored in the storage unit is copied. One of the plurality of image forming units is sent, the image forming unit forms an image on one side of the recording paper, and the image data on the other side is sent to another image forming unit. Note that an image is formed on the surface It is characterized in that an image is formed on the other surface to the paper.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

(First Embodiment) FIG. 1 is a block diagram showing an embodiment of an image forming apparatus according to the present invention.

In FIG. 1, A is a first image forming unit (image forming unit A), B is a second image forming unit (image forming unit B), and the internal structure and function of this embodiment are as follows. Exactly the same. 1A, 1B, and 1C denote a plurality of paper feed units (paper feed units) that accommodate recording paper (transfer paper);
Reference numeral 2 denotes a paper feed control unit, 211 denotes a paper feed switching unit, 3A denotes a first recording paper conveyance path, 3B denotes a second recording paper conveyance path, and 3X denotes a reversing unit for reversing recording paper. In 3X, there are provided a temporary stop means 8 for adjusting the discharge timing, and a discharge control unit 6 for controlling the same and controlling the discharge unit. 4
A is a first fixing device in a first recording paper transport path 3A, 4B is a second fixing device in a second recording paper transport path 3B, and 5 is a paper discharge unit that stores recording paper on which an image has been formed. It is.

Reference numeral 10 denotes an automatic document feeder, 20 denotes reading means for reading a document image on a document table to create image data, and 30 denotes storage means for storing the image data. Reference numeral 40 denotes an operation unit for performing settings such as single-sided printing and double-sided printing, paper feed size setting, recording paper alignment of the paper output unit 5, and the like. The plurality of image forming units A and B are connected to the operation unit 4.
An image is formed on a recording sheet based on the setting of 0 and the image data stored in the storage unit 30.

In the image forming section A, a photosensitive drum 1 is provided.
1, a charger 12, a laser writing device 13 composed of a semiconductor laser and an optical system, a developing device 14, a transfer separator 15, a cleaning device 16, and the like. The image forming section B has substantially the same structure as that of the image forming section A, and a description thereof will be omitted.

FIG. 2 is a block diagram of an image forming apparatus according to the present invention.

A plurality of originals stacked on the original tray are fed one by one onto a platen glass by an automatic document feeder (ADF) 10, and are exposed and scanned by a reading means 20, and the original image is scanned by an optical system. The image data is photoelectrically converted by an image reading device (CCD) 21 via the image sensor and is converted into image data. The image data is digitally converted by the next A / D converter 22 and sent to the next image data processor 23. The digital image signal input to the image data processing unit 23 is subjected to image processing such as density conversion, enlargement and reduction if necessary, and gradation correction processing, and is converted to image data suitable for image formation. Is sent to the next image storage unit (image storage means) 30.

The image storage unit 30 can store image data for a plurality of pages in page units. Further, the image data is compressed and stored as needed, and is expanded by a decompressor at the time of reading. As a result, image data is effectively stored in a limited capacity memory.

The next selector 31 reads out necessary data from image data stored in page units, and reads out the image data at timings when each of the plurality of image forming units A and B forms an image.
The image data is sent to the laser writing units 13A and 13B.
The laser writing units 13A and 13B temporarily store the sent image data in an internal buffer and form an image on the photosensitive drum 11 at a predetermined timing.

The first image forming unit A is a laser writing unit 1
3A and a process control unit 17A. The second image forming unit B includes a laser writing unit 13B and a process control unit 17B.
Having. The process control units 17A and 17B are connected to the overall control unit 50, and perform process control such as charging, development, transfer, and fixing around the photosensitive drum 11 necessary for image formation by a command of the overall control unit 50. I have.

The paper feed control unit 2, the paper discharge control unit 6, and the transport control unit 7 operate according to signals from the general control unit 50, respectively.

The paper feed control unit 2 switches the paper feed switching unit 211 according to an instruction from the general control unit 50, and takes out recording paper from an arbitrary paper feed cassette among the plural paper feed cassettes 1A, 1B and 1C. , An arbitrary image forming unit (recording unit) A,
B can be fed.

Here, when one of the paper feed cassettes 1A is alternately switched to the paper feed switching unit 211 to supply recording paper to each of the image forming units (recording units) A and B, the paper feed cassette 1
The paper feeding speed V1 from A to the registration roller is determined by the image recording unit (recording paper is fed from the registration roller and
Process speed V in the recording paper transporting unit until it leaves
It is possible to increase the number N to N by the number N of the plurality of image forming units. That is, in FIG. 1, the print productivity is improved by providing the two image forming units A and B so that the sheet feeding speed V1 is twice the process speed V2.

Further, the paper feed switching unit 211 is switched to continuously feed recording paper from the paper feed cassettes 1A and 1B corresponding to the image forming units A and B to the image forming units A and B via a paper feeding path that does not interfere with each other. It is possible to select a paper feed path that can feed paper to each of the image forming sections A,
Since there is no time loss to send recording paper to B alternately,
An image forming apparatus with high print productivity can be provided.

Similarly to the paper feed control, the paper discharge control unit 6 receives the recording paper discharged from any image forming unit after fixing by an instruction from the general control unit 50, and outputs the recording paper to any of the paper discharge units 5A and 5A. 5B
Can be discharged to A plurality of image forming units A and B
When the recording paper is discharged to one paper discharge unit 5A, a temporary stop mechanism is provided in a part of the reverse paper discharge unit 3X to control the timing of loading the recording paper on the paper discharge unit 5A, and a different mechanism is used. When the recording paper discharged from the image forming unit is discharged to the paper discharge unit 5A, two recording papers are discharged at the same time so that they do not interfere with each other and cause irregular paper discharge or jam. Or the discharge from the image forming unit A and the discharge from the image forming unit B are alternately controlled. Here, in the case of alternately discharging the paper, the paper discharging speed is set to N times the conveying speed of the image forming units A and B (double when the image forming units are two sets), similarly to the paper feeding. By discharging paper at high speed, it is possible to improve print productivity.

Further, similarly to the paper feed unit 1, the paper discharge unit 5 is also provided on a transport path which does not interfere with each other from the plurality of image forming units A and B.
By continuously discharging the recording paper to the paper discharge units 5A and 5B corresponding to the image forming units A and B, it is possible to improve the feeding property and productivity of the recording paper.

The transport control unit controls the recording paper transport unit between the first image forming unit A and the second image forming unit B and the reversing discharge unit (reversing unit) 3X during double-sided image formation. I do. Also, during double-sided recording, the recording paper on which single-sided recording has been performed has a transporting path such that the transporting path for recording the other side does not interfere with the sheet feeding path for single-sided recording.

The scanner control section 60 is a section for driving and controlling an optical system for reading an original.
It operates according to the command from.

The operation unit 40 is an operation panel including a display unit and key switches, for inputting conditions necessary for each image formation,
An image forming command or the like is input. Although not shown, the operation unit 40 has a key for selecting one-sided copying or two-sided copying, and a key for selecting standard, high-speed 1, and high-speed 2 of the automatic mode and the manual mode in the image forming mode. Yes, during single-sided copying, if the automatic mode is selected, high-speed copying is selected. If the standard mode is selected, a single image forming section to be operated by the operator can be selected. A mode in which recording paper is fed alternately to a plurality of image forming units to form a high-speed image,
In the mode, recording paper of a target size is set in a plurality of paper feed units, and a mode in which high-speed image formation is performed from each paper feed unit by a corresponding image forming unit via a dedicated paper feed path can be selected. Further, there is a key for selecting a paper discharge mode, and it is possible to select whether to discharge paper to the same paper discharge unit or to discharge paper to a plurality of paper discharge units. When outputting to a plurality of paper discharge units, the paper is discharged through a paper discharge path that does not interfere with a paper discharge unit corresponding to each image forming unit.

The overall control unit 50 has a function of managing, controlling and controlling the entire image forming apparatus, and receives a control signal, a status signal from each unit, and the like in each unit.

Next, the present invention will be further described with reference to a configuration diagram showing a recording paper transport path in FIG.

FIG. 3A is a configuration diagram showing a recording paper conveyance path at the time of single-sided recording by the image forming apparatus. There are mainly two types of recording modes on one side.
This will be described in (2).

(1) High-speed one-mode operation The recording paper is fed from one paper feed unit 1A, and the paper feed switching unit 21
1 is alternately conveyed to a plurality of image forming units B and A, and after the image formation, both recording sheets are merged and discharged through the same discharge path.

More specifically, a recording sheet fed at a high speed (for example, 100 sheets per minute) from the sheet feeding section 1A is first fed to the image forming section B by the sheet feeding switching section 211.
The recording paper is applied to a registration roller (not shown), temporarily stops, and is fed to the image forming unit B at a predetermined timing with the image data.

Here, the sheet is fed at a feeding speed of 100 sheets per minute to the registration roller, and the inside of the image forming section after the registration roller is 50 sheets per minute, which is a fraction of the speed of the image forming section for forming an image. The image is formed at a process speed at which the recording paper conveyance speed is reduced.

On the recording paper, first, the latent image exposed on the photoreceptor is developed by the developing device, transferred to the recording paper fed at a predetermined timing by the transfer device 15B, and the transferred image is fixed by the fixing device. You. The recording paper after fixing is fed next, and is temporarily stopped by a temporary stop means until the recording paper on which an image is formed in the image forming unit A passes through the fixing device and reaches a predetermined position.

When the rear end of the recording paper on which the image has been formed in the image forming section A is separated from the fixing device, the transport speed is increased by the number of minutes of the image forming section (in the present embodiment, twice as high per minute). 10
Paper discharge speed), and discharges the paper to the paper discharge unit. The recording paper that is temporarily stopped in the discharge path of the image forming unit B is sent to the discharge path at the timing when the recording paper is output from the image forming unit A, and the recording paper is discharged to the discharge unit. The paper is discharged alternately.
Thus, a one-sided copying operation can be performed at a processing speed about twice the processing speed of the image forming unit, and an image forming operation with high productivity can be realized.

In the copying operation, the recording sheets are alternately discharged in the above-described operation. However, the recording sheets from the image forming section A are simultaneously superimposed on the recording sheets from the image forming section B so that two sheets of the recording sheets are temporarily stopped. It is also possible to discharge the paper, thereby doubling the discharge conveyance speed when alternately discharging the paper. However, it is possible to discharge the paper at the image forming process speed, and the conveyance is controlled. The reliability is also easily improved. The details will be described later in the description of timing adjustment of paper discharge.

(2) High-speed two-mode operation Recording paper is fed from the two paper feed units 1A and 1B, and the paper feed switching unit 211 feeds a plurality of image forming units A and B through a paper feed path that does not interfere with each other. The paper is fed, and is discharged to another paper discharge unit via a paper discharge path that does not interfere with each other after image formation.

The recording paper is fed from the first paper feeding section 1A to the image recording section A (for example, at a feeding speed of 50 sheets per minute),
(For example, 50 sheets per minute at a sheet feeding speed), and these recording sheets are successively fed through a sheet feeding path that does not intersect with each other, thereby forming a first image. By forming images almost simultaneously at the forming section A (for example, at a processing speed of 50 sheets per minute) and at the second image forming section B (for example, at a processing speed of 50 sheets per minute), the overall processing speed is twice as high. 100 minutes). Accordingly, it is possible to feed and discharge at the process speed of the image forming unit without increasing the feeding and discharging speed, so that the control is easy and the reliability of the feeding and discharging is improved.

FIG. 3B is a configuration diagram showing a recording paper transport path during double-sided recording by the image forming apparatus.

The recording paper fed from the paper feeding section 1A is branched downward at the branching section of the paper feed switching section 211, and is conveyed along the second recording paper conveying path 3B to form a second image forming medium. The toner image is transferred to the first surface (back surface) of the recording paper in the transfer separator 15B of the part B, and the transferred image is fixed in the fixing device 4B. The fixed recording paper is turned upside down in the reversing unit 3X, and the toner image is transferred to the second surface (front surface) of the recording paper in the transfer separator 15A of the first image forming unit A. After the transfer, the recording paper is fixed on the first fixing unit 4A, and then placed on the tray of the paper discharge unit 5. While the preceding recording paper is image-processed on the second side (front side) in the first image forming unit A, the subsequent recording paper is subjected to the first image forming in the second image forming unit B.
The image processing of the front side (back side) is performed, and since the conveyance path of the preceding recording paper does not intersect or interfere with the subsequent recording paper, the double-sided image formation is continuously performed and the paper is discharged. As described above, since the two image forming units for the front side and the back side always operate,
High-speed, high-speed double-sided image formation becomes possible.

Next, a description will be given of control of timing adjustment of the discharge of the recording paper in the paper discharge unit 5.

In FIG. 1 and FIG. 3A, further downstream of the fixing device 4A provided downstream of the image forming section A,
A sensor PS-A for detecting passage of the recording paper is provided. Further, a fixing device 4B provided downstream of the image forming section B
Further downstream of the sensor P
SB is arranged.

Downstream of the conveyance path of the image forming section B and before reaching the junction from the image forming section A, a temporary stop means 8 is provided.
Is provided, and the drive is controlled by the sheet discharge control unit 6. The temporary stop unit 8 includes an image forming unit A and an image forming unit B.
The timing of each recording sheet discharged from the printer is adjusted, and simultaneous discharge or alternate discharge is controlled.

In the case of simultaneous paper ejection, first, the recording paper fed to the image forming section B and formed with an image is supplied to the sensor P
When the leading end of the recording paper is detected by SB, the conveyance of the recording paper is temporarily stopped by the temporary stop means 8. Next, the recording paper fed to the image forming unit A and having the image formed thereon is
At S-A, the passage of the leading end of the recording paper is detected, and after an adjustment time T1 for adjusting the timing with the detection signal has elapsed, the temporary stop is released and the drive of the temporary stop means 8 is resumed. The conveyed recording paper is conveyed, the recording paper from the image forming unit A and the recording paper from the image forming unit B are merged, and the recording paper is discharged onto the tray of the paper discharge unit 5 in a state where two recording papers are stacked. .

When the sheets are alternately discharged, similarly to the case of the simultaneous discharge, the recording sheet first fed to the image forming section B and formed with the image is detected by the sensor PS-B as having passed the leading edge of the recording sheet. Then, the recording paper conveyance is temporarily stopped by the temporary stop means 8. The recording sheet fed to the image forming unit A and formed with the image is detected by the sensor PS-A to detect the passage of the trailing edge of the recording sheet, and the suspension is released after an elapse of an adjustment time T2 for timing adjustment with this detection signal. Then, the driving of the temporary stopping means 8 is resumed, the recording paper conveyed from the image forming unit B is conveyed, and the image forming unit B is fed after the recording paper from the image forming unit A.
, And thereafter, the recording paper is alternately discharged onto the tray of the paper discharge unit 5.

When the recording papers are discharged alternately, when the recording papers are discharged from the fixing units 4A and 4B, the number of the image forming units (the number of the papers) is twice as large as the process speed of the image forming units A and B. By alternately discharging the paper at a conveyance speed of (twice in the embodiment), high-speed recording can be achieved by utilizing the processing capability of the image forming unit.

In addition, when the paper is discharged at the same time,
High-speed recording is possible at the same transport speed as the image forming unit,
Discharge control is easy and reliability is good.

In the present embodiment, the temporary stopping means is arranged at one place of the image forming section B. However, the temporary stopping means may be arranged at each of the image forming sections A and B.

FIG. 4 is a flowchart of a recovery process when an abnormality occurs in some of the plurality of image forming units. The flow of the recovery process is as follows:
It is called and executed in the main flow of the image forming apparatus.

First, whether an abnormality has occurred in the image forming portion A,
Determine whether the error flag is set. The error flag is a routine for judging an abnormality. An abnormality relating only to the image forming unit A is checked, and if an abnormality is found, the error flag is set. The abnormality relates to, for example, a recording paper jam in the image forming unit A or an abnormality of the laser writing device (writing system) 13. Here, a jam of a common portion, an abnormality of the entire control system, and the like are not included.

When there is an abnormality in the image forming section 1, the remaining number of recording sheets on which an image has not yet been formed among the number of recording sheets processed by the image forming section A, and the presence of an image The remaining number of recording sheets on which an image has not been formed is calculated. For example, if the image forming unit A is to output 5 copies of 15 originals, but a jam occurs on the sixth copy of the second copy, the number of remaining copies is 3 and the number of remaining copies is 10.

Next, the calculated number of remaining copies is added to the number of print copies counter which is to be processed by the image forming unit B, and the number of remaining copies of the image forming unit A is added to the number of print copies counter of the image forming unit B. Set the remaining number. This subroutine returns to the main flow after the processing is completed. However, in the image forming program, after the image forming unit B finishes printing the initially set number of copies, it prints the remaining copies of the image forming unit A added. Then, by looking at the recovery number counter, the remaining number of images that have become abnormal in the middle of a part of the image forming section A are read out from the image memory and printed.

In the above description, the image forming section B recovers when an abnormality occurs in the image forming section A. However, when an abnormality occurs in the image forming section B, the image forming section A The next image forming unit B is checked for abnormalities, and recovery processing is performed in the same manner as described above.

(Second Embodiment) FIG. 5 is a block diagram showing another embodiment of the image forming apparatus according to the present invention.

The illustrated image forming apparatus has two image forming units C and C which are further below the two image forming units A and B shown in FIG.
D is integrally formed. This image forming section (A to
With the addition of D), the paper feed units 1C and 1D and the recording paper transport path 3
C, 3D, a reversing unit 3Y, and a paper discharge unit 5B can be additionally provided to make paper supply and discharge more efficient and achieve high-speed recording.

(Third Embodiment) FIG. 6 is a block diagram showing still another embodiment of the image forming apparatus according to the present invention. In the figure, a first image forming unit A and a second image forming unit B are arranged substantially horizontally and horizontally, and a reversing unit 3X is provided between the image forming units A and B.

At the time of single-sided recording, the preceding odd-numbered recording paper fed from the right side of the paper supply unit 1 is sent from the recording paper transport path 3A to the first image forming unit A and is subjected to single-sided recording. After being fixed by the fixing unit 4A, the sheet is conveyed through a part of the vertical path of the reversing section 3X and further passes through the horizontal path above the second image forming section B and is placed on the tray of the sheet discharging section 5. Is placed. Subsequent even-numbered recording paper fed from the right side of the paper supply unit 1 is sent from the recording paper transport path 3B to the second image forming unit B, is recorded on one side, and is fixed by the second fixing unit 4B. After that, it is placed on the tray of the paper discharge unit 5.

When the recording paper is fed to the second image forming section B, paper feeding means such as a paper feeding roller and a separating roller (not shown) are provided so that the paper feeding section 1 can also feed paper from the left side. If the sheet is fed along the path 3C, the U-turn path can be eliminated, and the sheet feeding path can be simplified.

At the time of double-sided recording, the recording paper fed from the paper feed unit 1 is sent to the first image forming unit A. After the image is formed, transferred, and separated in the first image forming unit A, the image is fixed by the fixing unit 4A, and then the recording paper is reversed by the reversing unit 3X, and the same is performed in the second image forming unit B. The paper is discharged after the process.

With this configuration, a compact image forming apparatus in the height direction can be realized.

(Fourth Embodiment) FIG. 7 is a block diagram showing still another embodiment of the image forming apparatus according to the present invention. In the figure, a first image forming unit A and a second image forming unit B are arranged substantially horizontally and horizontally, and below the second image forming unit B in the middle of the conveyance path of the image forming units A and B. Reversal part 3
X is provided. Note that the second image forming unit B is configured to be symmetrical with the first image forming unit A.

At the time of single-sided recording, the preceding odd-numbered recording paper fed from the paper feeding unit 1 is moved from the recording paper transport path 3A to the first odd-numbered recording paper.
Is fixed to the first fixing unit 4A, and then conveyed through the horizontal path of the reversing unit 3X, where it is switched back and conveyed in the opposite direction. The sheet is conveyed upward and is placed on the tray of the sheet discharge unit 5 with the image forming surface facing upward.

The subsequent even-numbered recording paper fed from the paper supply unit 1 is sent from the recording paper transport path 3B to the second image forming unit B, where it is recorded on one side, and is fixed by the second fixing unit 4B. Thereafter, the sheet is placed on the tray of the sheet discharge unit 5 with the image forming surface facing upward.

At the time of double-sided recording, the recording paper fed from the paper feed unit 1 is sent to the first image forming unit A, and after the first image forming unit A forms, transfers and separates the image, the fixing device After fixing the image on the first surface (front surface) by 4A, pass through the reversing unit 3X as it is, make a U-turn upward and send it to the second image forming unit B, and the second surface (back surface) of the recording paper After being fixed by the second fixing device 4B, the sheet is conveyed upward and placed on the tray of the sheet discharge unit 5 with the second surface facing upward.

According to this structure, there is an effect that the heat efficiency is good because the fixing device is provided adjacent to the fixing device in the height direction.

(Fifth Embodiment) FIG. 8 is a block diagram showing still another embodiment of the image forming apparatus according to the present invention. In the figure, a first image forming section A and a second image forming section B are arranged substantially horizontally and horizontally, and there is provided a paper discharge section 5 having no reverse section and having paper discharge ports in both left and right directions. The second image forming unit B is configured to be symmetrical to the first image forming unit A, and is arranged upside down.

At the time of single-sided recording, the preceding odd-numbered recording paper fed from the paper feeding unit 1 is moved from the recording paper transport path 3A to the first
And is fixed on the first fixing unit 4A, and then conveyed upward, and the image forming surface is directed upward from the right side of the paper discharge unit 5 onto the paper discharge tray. And placed. The subsequent even-numbered recording paper fed from the paper supply unit 1 is sent from the recording paper transport path 3B to the second image forming unit B, is recorded on one side, and is fixed by the second fixing unit 4B. , And is placed on the tray of the paper discharge unit 5 from the left side of the paper discharge unit 5 with the image forming surface facing upward.

At the time of double-sided recording, the recording paper fed from the paper feed unit 1 is sent to the first image forming unit A, and after the first image forming unit A forms, transfers, and separates, the fixing unit After fixing the image on the first side (front side) by 4A, the sheet is conveyed substantially horizontally to the left in the figure, sent to the second image forming unit B, and recorded on the second side (back side) of the recording paper. After being fixed by the second fixing unit 4B, the sheet is conveyed upward and placed on the tray of the paper discharge unit 5 from the left side of the paper discharge unit 5 with the first surface facing upward.

With this configuration, since the recording paper is compact in the height direction and has no reversing mechanism at both sides and at one side, the reliability of the conveyance of the recording paper is improved.

(Sixth Embodiment) FIG. 9 is a block diagram showing still another embodiment of the image forming apparatus according to the present invention. In the figure, a first image forming section A and a second image forming section B are configured symmetrically, and the fixing devices of each image forming section are installed on both sides of the image forming apparatus, and are horizontally arranged. They are arranged side by side to form a closely integrated unit. Below the image forming units A and B, a sheet feeding unit 1 and a reversing unit 3X are provided.

At the time of single-sided recording, the preceding odd-numbered recording paper fed from the paper supply unit 1 is branched rightward in the drawing by the paper supply control unit 2 and is fed from the recording paper transport path 3A to the first image forming unit. A
And is fixed on the first fixing unit 4A, is conveyed upward, and is placed on the tray of the paper discharge unit 5 with the image forming surface facing upward.

The subsequent even-numbered recording paper fed from the paper feeding unit 1 is branched leftward in the figure by the paper feed switching unit 211 and sent to the second image forming unit B from the recording paper transport path 3B. Is fixed by the second fixing device 4B, is conveyed upward, passes above the unit including the image forming units A and B, and is placed on the tray of the paper discharge unit 5 on the image forming surface. Is placed face up.

At the time of double-sided recording, the recording paper fed from the paper feeding unit 1 is first sent to the second image forming unit B, and after the second image forming unit B forms an image, transfers and separates it, Fixing device 4
After the image on the first surface (back surface) is fixed by B, after passing through the lower reversing section 3X, it makes a U-turn upward, is branched rightward in the drawing by the paper feed control section 2, and from the recording paper transport path 3A. The sheet is sent to the first image forming section A, is recorded on the second surface (front side) of the recording sheet, is fixed by the first fixing device 4A, and is then conveyed upward to be on the tray of the sheet discharging section 5. Is placed with the second surface facing upward.

By arranging the fixing devices on both sides of the image forming apparatus, there is an effect of preventing an increase in the internal temperature due to the heat of the fixing devices.

In this embodiment, a copying machine is used as an example. However, the present invention is not limited to this, and a printer such as a laser beam printer may be used.

[0078]

As described above, the image forming apparatus capable of double-sided recording according to the present invention is not an apparatus in which a plurality of conventional image forming apparatuses are combined and a reversing and conveying apparatus is connected. Image data is created from external image information, the image data is digitally processed and stored in a storage unit, and the stored image data is stored in a plurality of image forming units housed in one image forming apparatus. (Multi-engine) has the effect of controlling the operation of a plurality of image forming units at all times, even on one side or both sides, to enable high-speed image formation.

Further, the reliability is improved by having a paper feed path that does not interfere with each other, and the shortest paper feed is achieved by feeding paper through a paper feed path from a paper feed unit that has a one-to-one correspondence with the image forming unit. By feeding paper continuously to each image forming unit in the paper path, high-speed image formation on one side can be performed.

In addition, in the case of double-sided copying, the conveyance path of the recording sheet on which one-side recording has been performed is prevented from intersecting and interfering with the sheet feeding path to the next first-side image forming unit, so that productivity and reliability on both sides are improved. This has the effect of improving the performance.

Further, reliability is improved by having a paper discharge path that does not interfere with each other, and high-speed image formation on one side can be performed by continuously discharging paper to a plurality of paper discharge units.

Further, in the case of forming an image on one side, when a plurality of image forming units discharge paper to one paper discharge unit, at least one paper discharge path is provided with a primary stop means, the timing is adjusted, Alternatively, the discharge is performed in an overlapping manner, thereby eliminating a jam or the like at the merging portion and improving the reliability of the discharge.

When an image is formed on a single side by a plurality of N image forming units, the conveying speed (process speed) of the recording paper in the image forming unit is set to 1 / N of the conveying speed of the recording paper from the paper discharging unit. This makes it possible to increase the speed of one image forming apparatus with a simple configuration.

In the case of forming an image on one side, even if a part of the plurality of image forming units cannot form an image due to a jam or the like, the image forming operation is performed by another image forming unit without interrupting the image forming operation. There is an effect that an image can be formed.

Further, by providing paper feeding means capable of feeding paper from both sides of the paper feeding unit, the paper feeding path to the image forming unit is shortened, simplified, and improved in reliability.

[Brief description of the drawings]

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

FIG. 2 is a block diagram of an image forming apparatus according to the present invention.

FIG. 3 is a configuration diagram illustrating a recording paper transport path during single-sided recording and double-sided recording by the image forming apparatus.

FIG. 4 is a flowchart of a recovery process when an abnormality occurs in the image forming unit.

FIG. 5 is a configuration diagram showing a second embodiment of the image forming apparatus according to the present invention.

FIG. 6 is a configuration diagram showing a third embodiment of the image forming apparatus according to the present invention.

FIG. 7 is a configuration diagram showing a fourth embodiment of the image forming apparatus according to the present invention.

FIG. 8 is a configuration diagram showing a fifth embodiment of the image forming apparatus according to the present invention.

FIG. 9 is a configuration diagram showing a sixth embodiment of the image forming apparatus according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 paper feed section (paper feed cassette) 2 paper feed control section 211 paper feed switching section 3A first recording paper transport path 3B second recording paper transport path 3X, 3Y reverse discharge section (reverse section) 4A, 4B fixing Apparatus 5 Discharge unit 6 Discharge control unit 8 Temporary stop unit 10 Automatic document feeder (ADF) 11 Photoconductor drum 13 Laser writing device 15 Transfer separator 20 Reading unit 30 Storage unit (image storage unit) 40 Operation unit 50 Overall Control unit 60 Scanner control unit A First image forming unit (image forming unit A) B Second image forming unit (image forming unit B) PS-A, PS-B sensor

Claims (13)

[Claims] 1. An image forming apparatus comprising: a storage unit that stores image data; and a plurality of image forming units that form an image on a recording sheet based on the image data stored in the storage unit. When forming an image on one side of paper, the same image data or different image data in the storage unit is sent to the plurality of image forming units, and the plurality of image forming units perform image formation substantially simultaneously. When performing image formation on both sides, image data of one of the front and back surfaces of the document stored in the storage unit is sent to any of the plurality of image forming units, and is recorded by the image forming unit. An image on one side is formed on paper, and image data on the other side is sent to another image forming unit, and the image forming unit on the other side forms an image on recording paper on which an image is formed on one side. Image forming apparatus . 2. A conveyance linking a recording paper conveyance path of an image forming unit for forming an image on one side of the front and back surfaces of a document with a recording paper conveyance path of an image forming unit for forming an image on the other side. The image forming apparatus according to claim 1, wherein a reversing unit that reverses the recording paper at the time of forming a double-sided image is provided on the path. 3. When forming an image on one side of a recording sheet, a plurality of image forming sections for forming an image are provided with a sheet feeding path which conveys the recording sheet from each of the plurality of sheet feeding sections and does not interfere with each other. The image forming apparatus according to claim 1, wherein: 4. When forming an image on one side of the recording paper,
The image forming apparatus according to claim 3, wherein the recording paper is fed from the same number of paper feeding units corresponding to each of the plurality of image forming units via a paper feeding path that does not interfere with each other. 5. When performing image formation on both sides of a recording sheet, the conveyance path of the recording sheet after the image formation on one side and the conveyance path of the recording sheet before the image formation on the one side do not interfere with each other. The image forming apparatus according to claim 1, wherein: 6. When forming an image on one side of the recording paper,
2. The image forming apparatus according to claim 1, wherein the recording sheets discharged from the plurality of image forming units at substantially the same time are discharged through a discharge path that does not interfere with each other. 3. 7. When forming an image on one side of the recording paper,
The image forming apparatus according to claim 6, wherein the recording sheets discharged from the plurality of image forming units at substantially the same time are discharged to a plurality of discharge units along a discharge path that does not interfere with each other. 8. When discharging a plurality of recording sheets, each having an image formed on one side of the recording sheet, substantially simultaneously from the plurality of image forming sections to a single discharging section, the discharge section of at least one image forming section is provided. The image forming apparatus according to claim 1, further comprising a temporary stop unit for adjusting the timing of paper discharge between the paper discharge unit and the one paper discharge unit. 9. When one of the plurality of image forming units discharges a plurality of recording sheets, each having an image formed on one side thereof, to one discharging unit, the plurality of image forming units causes the one paper discharging unit to be temporarily stopped by the temporary stopping unit. The image forming apparatus according to claim 8, wherein the sheet is discharged while being superposed on the image forming apparatus. 10. When a plurality of recording sheets, each having an image formed on one side thereof, are discharged from the plurality of image forming sections to a single discharge section at substantially the same time, the one paper discharge section is controlled by the temporary stop means. 9. The image forming apparatus according to claim 8, wherein the sheet is discharged alternately without overlapping the sheet. 11. When the number of said plurality of image forming units for forming an image is N, the conveying speed of a paper feeding unit or a paper discharging unit for feeding a recording sheet to the image forming unit is determined by the recording speed in said image forming unit. 2. The image forming apparatus according to claim 1, wherein the speed is set to be N times as large as the paper transport speed. 12. A detecting means for detecting whether or not the image forming unit is capable of forming an image, wherein when the detecting means detects at least one of the plurality of image forming units that an image cannot be formed, The image forming apparatus according to claim 1, further comprising a control unit configured to substitute an image forming unit that cannot form an image for another image forming unit. 13. A plurality of paper feeding means for feeding recording paper from one paper feeding unit to different paper feeding paths, respectively, and a paper feeding unit for conveying the recording paper from the plurality of image forming units to different image forming units. The image forming apparatus according to claim 1, further comprising: a plurality of conveyance paths; and a sheet supply control unit configured to sequentially control the plurality of sheet supply units.