JPH0830050A - Image forming device - Google Patents

Abstract

PURPOSE:To provide a high copying productivity for each paper sizes by making the number of paper sheets carried in-machine changeable depending on the sizes of transfer paper sheets. CONSTITUTION:When a copy button 32 is pressed (ON) after a copying number is set by using a ten key 34, originals on an automatic original feeding part 11 are automatically fed, original information is read by a reading part 12, image-processed by an image processing part 13 and then stored in an image storage part 22. When scanning of all the originals is confirmed, whether transfer paper sheets are small or not in size is checked. This checking of the transfer paper sizes is performed by a paper size detecting means 25 provided in the vicinity of a paper feeding part 16 or by checking transfer paper sizes differently obtained. When the transfer paper sizes are small, the limit of paper sheets to be carried is set to, for instance, 5. When the transfer paper sizes are not small, the limit to be carried is set to, for instance, 3.

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 which is equipped with automatic document feeding means and is capable of double-sided copying, and more particularly to an image forming apparatus having a non-stack type automatic reversing unit.

[0002]

2. Description of the Related Art As copying machines, models having excellent processability and operability have been provided year by year. Conventionally, the automatic document feeder automatically feeds the original document to the exposure position on the original table by manually feeding it, and it automatically synchronizes the original document to the exposure position. Then, image formation was performed. However, due to the spread of digitalization and the reduction in cost of memory, a memory (image storage unit) is provided in the machine, the originals are conveyed one by one to the exposure position by the automatic original conveying means, and the reading having the photoelectric conversion means such as CCD is performed. The original information at the exposure position is read by the means, all the original information is temporarily stored in the memory, and when the image is formed, the image information of the required page is called from the memory to copy regardless of the operation of the automatic original conveying means. Came to be done. Conventionally, when copying a plurality of copies of a document consisting of a plurality of sheets, the automatic document feeder circulates the document a plurality of times to obtain a plurality of copies, but a so-called electronic RDH accumulating in the memory is adopted. By doing so, such an operation became unnecessary.

Further, many copiers having a double-sided copy function have come to be provided. That is, an automatic reversing unit (ADU) is installed in the machine, and the transfer paper is reversed and conveyed inside the machine by the ADU without copying the transfer paper that has finished copying on one side to the outside of the machine. After that, it is discharged to the outside of the machine. A
The DU is equipped with a stacker inside the machine, a stack type ADU that temporarily stores the transfer paper that has finished copying one side in the stacker and then copies the back side, and a non-conveyor that does not have a stacker and only has a reverse conveyance path. There is a stack type ADU. Stack type ADU and non-stack type A
Each DU has its own advantages and disadvantages.

[0004]

In the image forming apparatus provided with the non-stack type ADU, which has been conventionally provided, the number of sheets that can be conveyed in the machine in the reverse conveying path in the non-stack ADU mode is limited to one. However, there is a problem that the copy productivity is not in a satisfactory state. On the other hand, the applicant is a non-stack A
A proposal has been made to enable transfer of a plurality of single-sided copy sheets of transfer paper into the reverse conveyance path in the DU mode. According to this proposal, the non-stack type image forming apparatus having the electronic RDH has excellent productivity as compared with the stack type image forming apparatus.

However, the image forming apparatus according to the above proposal is
The number of sheets transported inside the machine was fixed. Since this fixed number of sheets is set based on the maximum size transfer paper, when performing double-sided copying using a small size transfer paper, the number of copies / minute should normally be large for a small size transfer paper. However, there was a problem that the same productivity as that of the transfer paper of the maximum size could be obtained (first problem).

Further, in the above proposal, in order to be able to convey a plurality of transfer papers in the reverse conveyance path, the in-machine conveyance number limitation information is necessary (second problem).

An object of the present invention is to solve the above-mentioned first and second problems and to provide an image forming apparatus having a highly productive non-stack type ADU.

[0008]

In the image forming apparatus having the non-stack type automatic reversing unit and the transfer sheet size detecting means, in the case of the mode using the non-stack type automatic reversing unit, An image forming apparatus (first invention for solving the first problem) characterized in that the number of sheets conveyed in the machine is changed according to the size of the transfer paper detected by the paper size detecting means; In an image forming apparatus having an automatic reversing unit, in the mode in which the non-stack type automatic reversing unit is used, the paper feed restriction information is added to the information for each transfer paper when the in-machine conveyance limit number is reached, and the paper feed is performed. This is achieved by an image forming apparatus (second invention for solving the second problem), which determines whether or not to start the next sheet feeding in accordance with the limitation information.

[0009]

1 is a block diagram showing an embodiment of an image forming apparatus of the present invention, and FIG. 2 is a block diagram showing a circuit structure. An automatic document feeder 11 is located on the upper surface of the image forming apparatus main body 10. The automatic document feeder 11 takes out one of the documents stacked on top and feeds it onto the platen glass for reading the document image. Further, the automatic document feeder 11 is capable of inverting both sides of a document and automatically feeding the document onto the platen glass.

A reading unit 12 is composed of a moving mirror, an image forming optical system, and a light receiving element such as a CCD, and scans a document placed at an exposure position on the platen glass to scan a document such as a CCD at the image forming position. The light receiving element reads the image information of the document and outputs the image information as an image signal. 13 is an image processing unit,
The image signal output from the reading unit 12 is converted and processed into a recording signal suitable for laser recording. The recording signal is temporarily stored in the image storage unit 22 for each page. An image output unit 14 is a laser optical system that emits light in response to a storage signal called from the image storage unit 22 and optically scans the rotating photosensitive drum 15a to form a latent image.

The photosensitive drum 15a and its peripheral portion are provided.
An image forming process unit 15 including a charging device, a developing device, and the like develops the latent image into a toner image, and the toner image is fed to the paper feeding unit 16.
The transfer / separation unit 15b performs transfer on the transfer paper discharged from any one of (a), (b), (c), and (d) in a synchronized manner, and is separated from the photosensitive drum 15a and fixed. Guided to vessel 17. The transfer sheet holding the toner image is fixed by the fixing device 17, and then is ejected as a single-sided copy from the paper ejection unit 18 in the single-sided copy mode.

Further, in the double-sided copy (ADU) mode, the transfer paper which has been fixed on the one-sided toner image on the transfer paper by the fixing device 17 has been transferred to the non-stack automatic reversal unit (ADU) 19 After that, the toner image is transferred to the back surface of the transfer paper in the image forming process unit 15, and the fixing device is fixed.
The toner image adhered to the back surface is fixed at 17 and then discharged from the paper discharge unit 18. Although not shown, the paper discharge unit 18 is provided with a finisher capable of finishing such as stapling, and staple processing can be performed for each set of a plurality of discharged transfer papers. Has become.

A plurality of paper detection means 25 are provided along the transfer paper conveyance path so that the presence or absence of the transfer paper being conveyed inside the machine can be detected. An operation panel 30 (not shown) is provided on the upper surface of the image forming apparatus main body 10, and a copy mode selection button 3 for selecting one-sided copy or two-sided copy.
1, a copy button 32 that is pressed at the start of copying, a numeric keypad 34 for setting and inputting the number of copies, a display section 35 using liquid crystal, etc.
Are provided, all of which are connected to the control unit 21.
The control unit 21 is a CPU that performs arithmetic processing according to the present invention and controls image formation.

(Embodiment 1) First Invention In the image forming apparatus of the present invention, so-called high-speed processing is performed in which a large number of copies are made within a fixed time, and the transfer paper is continuously transferred with a slight space between the transfer papers. The image is conveyed and the image is recorded on the transfer paper. Therefore, in the double-sided copy mode, for example, A4 size or B5 is provided on the circulating in-machine conveyance path formed by the transfer / separation unit 15b and the ADU conveyance path 19a.
For small size transfer papers, there is a maximum of 5 transfer papers as the in-machine conveyance limit number, and for example, for B4 size or A3 size large size transfer papers, there is a maximum of 3.
The number of transfer sheets that have been subjected to single-sided fixing is present as a limited number of sheets to be conveyed in the machine, and is in a state of being conveyed in the machine counterclockwise in the figure.

In FIG. 3, the copy mode selection button 31
It is a flowchart figure of this invention at the time of selecting DU use mode (duplex copy mode). When the copy button 32 is pressed (ON) (FA1) after the number of copies is set by the ten keys 34, the document of the automatic document feeder 11 is automatically fed, and the document information is read by the reading unit 12 (scan), and image processing is performed. After the image processing is performed by the unit, the image is stored in the image storage unit 22. It is checked whether or not the scanning of all the originals has been completed (FA2), and when it is confirmed that the scanning of all the originals has been completed, it is determined whether or not the transfer paper is a small size (for example, A4 or B5 size). A check is made (FA3). Check the transfer paper size in the paper feed unit 16
This is performed by checking the paper size detecting means 25 provided in the vicinity of or the transfer paper size manually input separately.

When the transfer paper size is a small size (for example, A4 or B5 size), the transport limit number is set to 5, for example (FA4A). When the transfer paper size is not small (for example, B4 or A3 size), the transport limit number is set to 3 (FA4B). Of course, the transport limit number set here is a larger integer for the small size than for the large size.

The number of sheets of transfer paper that has been copied on one side (back side) is compared with the number of sheets that can be conveyed in the machine (5 for small size, 3 for large size) (FA5), and the number of sheets to be conveyed inside the machine reaches the number of conveyance inside the machine. Then, the other side (back side) of the transfer paper in the in-machine conveyance path is copied, fixed, and then double-sided copied from the paper discharge unit 18 and discharged (FA6B).

When the number of sheets of transfer paper that has been subjected to one-sided copying is less than the number of sheets that can be conveyed in the apparatus, the sheet is fed from the sheet feeding section 16 (FA6A), and one-sided copying is performed.
It is conveyed into the reverse conveyance path. When paper is fed from the paper feed section 16, the number of paper feed counter in the RAM 26 is incremented to 1 (FA7). It is checked whether or not the counted number of fed sheets has reached the previously manually input set copy number (FA8). When the set copy number has not been reached, the flow returns to FA3. On the other hand, when the counted number of fed sheets reaches the set number of copies, double-sided copying is performed on the fed transfer sheet, and the copy operation ends (FA9).

As described above with reference to the flow chart, according to the present invention, by making the number of sheets conveyed in the machine variable depending on the paper size, high copy productivity can be obtained for each paper size. In the above description, A3 size and B4 size are large size, A4 size,
Although the embodiment has been described in which the transport limit number can be switched between the B5 size and the small size in two stages, it is of course possible to change the transport limit number for each transfer sheet size or for each different group.

(Embodiment 2) Second Invention In the image forming apparatus of the present invention, in the mode in which the non-stack type automatic reversing unit is used, the paper feed restriction information is transferred for each transfer paper when the in-machine conveyance limit is reached. It is added to the mail information that the user has, and whether or not the next sheet feeding can be started is determined according to the sheet feeding restriction information. The image forming apparatus of the present invention has mail information that enables rewriting, and in the duplex copy mode, the RAM 24 stores mail information for each transfer sheet that has finished single-sided copying while being conveyed in the machine. There is. As the mail information held for each transfer sheet, sheet feed limitation information is recorded together with page information such as the number of sheets after the start of copying, the number of original pages, image information, and the like. One bit is assigned to the paper feed restriction information, and the number of sheets conveyed in the machine is a limit value (for example, the fifth sheet in the case of the small size in the previous embodiment).
When the number of sheets reaches, the paper feed restriction information indicating that the transfer paper is full in the in-machine conveyance path and the paper cannot be fed any more is added.

In the present invention, the control unit 21 calls the mail information held for each transfer sheet and determines whether or not the next paper feeding can be started according to the paper feed restriction information recorded in the mail information.

In FIG. 4, AD is selected by the copy selection button 31.
It is a flowchart figure of this invention at the time of U use mode (duplex copy mode) selection. In the following description, in order to facilitate the description, an example in which four copies of three originals as shown in the table below are copied will be described.

[0023]

[Table 1]

In FIG. 4, after the number of copies (for example, 4) is set by the ten keys 34 and the copy button 32 is pushed (ON) (FB1), the originals (for example, 3 sheets) in the automatic original feeding section 11 are automatically fed. The document information (for example, six faces) of all documents is read (scanned) by the reading unit 12, image processing is performed by the image processing unit, and then stored in the image storage unit 22. Next, as the information to be recorded on the transfer paper of the first page, the image information of the total number of originals (for example, 6) is called from the image storage unit 22 (FB2), and the paper feeding unit
The transfer paper is fed from 16 (FB3), and the image information of the total number of document surfaces (for example, 6) is recorded on the fed transfer paper.

When the transfer paper is fed by the FB3,
The number of conveyed sheets counter is incremented to 1 (FB
4). Further, as the information to be recorded on the transfer paper of the next page, the image information of the original page number obtained by subtracting 2 from the previous page (for example, 4 pages) is called from the image storage unit 22 and set (FB5). Here, when the number obtained by subtracting 2 from the number of document surfaces on the previous page is 0 as the information to be recorded on the transfer sheet, it means that one part of the transfer sheet is fed. Next, it is checked whether or not the number of conveyed sheets counted in FB4 has reached a set number of copies (for example, 4 sets) (FB
6) When the set number of copies has not been made, it is checked whether or not the count value of the limit number counter for counting the number of transfer sheets in the in-machine conveyance path has reached the limit value (for example, 5 for A4 size). (FB7A), if the limit value has not been reached, the process returns to FB3. When the count value of the limit number counter reaches the limit value (for example, 5), the feed limit information is added to the mail information corresponding to the last transfer sheet on which the feed limit information is fed (FB
8). AD is applied to the transfer paper that has been copied on one side.
When U is reversed, the number of pages subtracted 1 from the number of screens previously copied is set in the mail information (FB9), and is conveyed inside the machine and set on FB9 on the transfer paper (1 from the number of pages already copied on one side). Image recording is performed on the number of sides (FB10).

It is checked whether or not the transfer paper holding the paper feed restriction information is inverted by ADU (FB11), and the check is continuously repeated until the transfer paper in the in-machine reverse conveyance path is exhausted, and the paper feed restriction information is held. When the transferred transfer paper finishes the ADU reversal, the number of the pages obtained by subtracting 1 from the number of the pages of the last page of the previous cycle is set as the leading transfer paper of the next cycle (F
B12), clears the conveyed number counter (FB13), and returns to.

When the above-mentioned actual example shown in Table 1 is displayed on the copy, the copy control is performed as shown in the table below.

[0028]

[Table 2]

As described above with reference to the flow chart, it becomes possible to control the paper feed and calculate the next page by adding the restricted number of sheets in the machine as mail information.

[0030]

According to the present invention (first invention) in the ADU mode in the image forming apparatus equipped with the non-stack type ADU, the number of sheets conveyed in the machine can be changed according to the paper size of the transfer paper, so that each paper size can be changed. And high copy productivity can be obtained.

Further, according to the present invention (the second invention), the control of the image formation including the sheet feeding by the ADU capable of carrying a plurality of sheets in the machine is performed easily and accurately, and high copy productivity is secured. It was decided.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing a control system of the image forming apparatus of the present invention.

FIG. 3 is a flowchart of the present invention (first invention).

FIG. 4 is a flowchart of the present invention (second invention).

[Explanation of symbols]

 10 Image forming apparatus main body 11 Automatic document feeding unit 12 Reading unit 14 Image output unit 15 Image forming process unit 19 Non-stack / auto reverse unit 21 Control unit 22 Image storage unit 24 RAM

Claims (3)

[Claims] 1. An image forming apparatus having a non-stack type automatic reversing unit and a transfer sheet paper size detecting means detects the paper size detecting means in a mode in which the non-stack type automatic reversing unit is used. An image forming apparatus characterized in that the number of sheets conveyed in the machine is changed according to the size of the transferred paper. 2. In an image forming apparatus having a non-stack type automatic reversing unit, in a mode in which the non-stack type automatic reversing unit is used, paper feed restriction information is transferred for each transfer sheet when the in-machine conveyance limit number is reached. An image forming apparatus, characterized in that it is added to information that the user has, and whether or not to start next sheet feeding is performed according to the sheet feeding restriction information. 3. The image forming apparatus according to claim 2, wherein the information is information stored in a storage unit.