JPH04149462A - Image forming device - Google Patents

Abstract

PURPOSE:To facilitate the reading of an original by making timing for feeding a paper to an image forming means relatively earlier than the start of the scanning of an optical system in the case of the transfer of a small size original. CONSTITUTION:In the case of performing the transfer of the original which is bound right and whose image is transferred to both sides of a transfer paper in order such as a small size original and a large size original, the timing for feeding the paper to the image forming means P is made relatively earlier than the start of the scanning of the optical system L by a timing control means so that the image is transferred to the latter half part side of one side when the transfer of the small size original is performed, then the image of the large size original is transferred to the other side of the selected transfer paper and the paper is fed to the means P again. On the other hand, in the case of performing the transfer of the original which is bound left and whose image is transferred to both sides of the transfer paper in order such as the large size original and the small size original, the image of the large size original is transferred to one side of the transfer paper and the timing for feeding the paper to the means P is made relatively earlier than the start of the scanning of the optical system L so that the image is transferred to the latter half part side of the other side of the selected transfer paper when the transfer of the small size original is performed. Thus, the reading of the original is facilitated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a circulation type automatic document feeder that automatically feeds large and small size documents, an image forming means that forms an image by scanning with an optical system, The present invention relates to an image forming apparatus having a refeeding function for refeeding the transfer paper that has been transferred on one side to the image forming means so as to transfer the original document onto both sides of the fed transfer paper.

[Conventional technology]

Conventionally, in a circulating automatic document feeder (RDH), for example, A
By mixing originals of different sizes, such as A3 size and A3 size, and automatically feeding these originals, the first original is transferred to one side of the transfer paper, and then the second original is transferred as described above. Copying machines (image forming apparatuses) that perform single-sided original/double-sided copying that transfer images onto the other side of paper are known.

In such an image forming apparatus, the transfer paper that matches the size of the larger original of the first and second originals is selected automatically (Japanese Patent Application Laid-open No. 63-309976@publication) or using the operation unit. If the first document is A4 size and the second document is A3 size, the transfer paper is A3 size.
Set to size.

On the other hand, due to the configuration of the device, the conveyance direction of the transfer paper is opposite when it is transferred to the front side of the transfer paper and when it is transferred to the back side of the transfer paper, so the first document is A4 size and the second document is is A
In the case of 3 sizes, the A4 size original will be transferred to the first half of the transfer paper in the transport direction (left side in Figure 6 (a)), and conversely, if the first sheet of the original is A3 size If the second document is A4 size, the A4 size document will be transferred to the first half of the transfer paper in the conveyance direction (the right side in FIG. 6(b)).

In addition, the above image forming apparatus is equipped with A3 size transfer paper.
A paper folding unit is provided to fold the paper to the same size, and folds the transferred paper into a two-character shape.

[Problem to be solved by the invention]

However, in the above-mentioned paper folding unit, the first half of the transfer paper in the transport direction is folded, so if the first document is A3 size and the second document is A4 size, the A4 size document part will be folded into a two-character shape. This will make it difficult to read A4 size documents.

The present invention has been made in view of the above problem, and when originals of different sizes are transferred to both sides of transfer paper, the transfer position of the small-sized original is adjusted appropriately to prevent the small-sized original from being folded. It is an object of the present invention to provide an image forming apparatus that facilitates reading of a document by switching the image forming apparatus and improves appearance.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a circulation type automatic document feeder that automatically feeds large and small size originals, an image forming means that scans with an optical system and forms an image, and a system that automatically feeds the originals. In an image forming apparatus, the image forming apparatus has a refeeding function for refeeding the transfer paper that has been transferred on one side to the image forming means in order to transfer the original to both sides of the transfer paper, a preliminary feeding means for preliminarily feeding the original; A detection means for detecting the document size of each document during preliminary feeding, a storage means for storing the detected document size, and a transfer paper corresponding to a large size of the document to be transferred on both sides of the transfer paper. The transfer paper selection means that selects the transfer paper selection means to feed the In order to transfer the small-sized original to the latter half of the transfer paper, the timing of feeding the paper to the image forming means is set relative to the start of scanning of the optical system when transferring the small-sized original. and timing control means for relatively advancing the timing.

(Function) According to the image forming apparatus having the above configuration, the originals placed on the circulation type automatic document feeder are prefed, the original size of each original is detected during the preliminary feeding, and the original size of each original is detected. The sizes are stored, and a transfer sheet corresponding to the large size of the document to be transferred onto both sides of the transfer sheet is selected and fed. If the documents to be right-bound and transferred to both sides of the transfer paper are in the order of small size and then large size, the timing of feeding the paper to the image forming means when transferring the small size document is relative to the start of scanning of the optical system. The small-sized original is transferred to the second half of one side of the transfer paper, and the large-sized original is transferred to the other side of the selected transfer paper and re-fed to the image forming means. Ru.

On the other hand, if the originals are left-bound and transferred to both sides of the transfer paper in the order of large size and small size, the large size original is transferred to one side of the transfer paper, and when the small size original is transferred, it is transferred to the image forming means. The paper feeding timing is advanced relative to the start of scanning by the optical system, and the small-sized original is transferred to the second half of the other side of the selected transfer paper.

(Embodiment) FIG. 2 is a schematic configuration diagram showing an example of an image forming apparatus according to the present invention.

The image forming apparatus has a contact glass 20 and a circulating automatic document feeder (RDH) 21 on its upper surface, an optical system inside, a rut forming means P and a refeeding mechanism Q, and a roller on the transfer paper discharge side. A paper folding unit R and a stable unit S are provided.

When the duplex copy mode is set using an operation unit (not shown), originals of different sizes, such as A4 size and A3 size, loaded on the RDH 21 are sequentially transferred onto both sides of the transfer paper, and then the paper 2 by folding unit R
It is folded into a letter shape (hereinafter referred to as a Z-fold).

The RDH 21 includes a document table 211, a paper feed roller 5212, a registration roller 213, a transport belt 214, and a transport roller 2.
15, discharge rollers 216, 218, discharge guide section 217
and a document size sensor 219. When detecting the number of originals and the original size of each original by pre-circulating a plurality of originals stacked on the original platen 211, the paper feed roller 212 and the registration roller 21
3, the originals are conveyed one by one starting from the lowest original, and the number of originals and the original size of each original are detected and stored by an original size sensor 219, which will be described later. Thereafter, the document passes through the discharge guide section 217 by the transport belt 214 and discharge rows 5216 and 218, and is placed on the document table 211 again. In addition, when transferring originals to transfer paper, the originals are conveyed one by one starting from the lowest original, sent out onto the lath 20, and stopped at a predetermined position on the contact glass 2o by the conveyor belt 214. . Thereafter, the original is placed on the original table 211 again by the conveyance belt 214 and discharge rollers 216 and 218.

The document size sensor 219 is composed of, for example, a plurality of seven-dimensional sensors, and detects the number and size of each document sent out from the document table 211, and outputs the detection signal to the control system. That is, the document size sensor 21
9, for example, arranges photo sensors in parallel in the width direction of the document path, detects the width of the document based on the state of the photo sensor that detects the document, and detects the number and size of the document based on the detection time of the document passing through. . Then, the document size is detected based on these widths and dimensions.

The optical system is composed of a light source consisting of a halogen lamp 22 and a reflector plate 23, reflectors 1124, 25, 26, a lens section 27, and fixed mirrors 28, 29, 30. Then, when the original set in the RDH 21 is fed toward the contact glass 20 and stopped at a predetermined position on the contact glass 20 to start the transfer operation, the light from the light source illuminates the original on the contact glass 20. The reflected light is guided to the lens portion 27 via the reflecting mirrors 24 to 26, and then passes through the fixed mirrors 28 to 30 to expose the photosensitive drum 31 described below.

The image forming means P includes a photosensitive drum 31, a charging device 32,
Blank lamp 33, developing device 34 for multicolor copying
．． 35, transfer device 36, separation device 37 and cleaning device! It is equipped with 38 mag.

The surface of the photosensitive drum 31 is uniformly charged by the charging device 32 and then exposed to the reflected light to form an electrostatic latent image. The electrostatic latent image is converted into toner by the developing device 34 or 35, and then transferred to the transfer device 3.
6 onto a transfer paper, and separated from the photosensitive drum 31 by a separating device M37. Furthermore, as paper feeding mechanisms, paper feeding cassettes 39, 40, . A paper feeding roller 41, 42 and a pair of registration rollers 43, 44 are provided, and these paper feeding mechanisms feed the transfer paper to the photosensitive drum 31, and transfer is performed. Further, a cleaning device 38 cleans the toner remaining on the surface of the photoreceptor drum 31 after the transfer. A conveyor belt 45 and a fixing device 4 are installed downstream in the conveyance direction of the transfer paper after transfer.
6, a discharge roller 47, and the like are provided. The transfer paper after the transfer to one side is fixed by the fixing unit @1146, and then conveyed to the retransmission mechanism Q for transfer to the other side.

The retransmission mechanism Q includes a switching guide 48 for switching to the retransmission side, a switching guide 49 for double-sided switching, a reversing guide 1150, a reversing belt 51 for switchback, a switchback guide section 52, an intermediate tray section 53, a forwarding roller 54, It includes a front shifting belt 55, a paper refeeding roller 56, and the like. When the double-sided copy mode is set, the original is first transferred to one side, and the transfer paper is conveyed to the re-feeding mechanism Q via the switching guides 48 and 49, and is once conveyed to the switchback guide section 52 by the reversing belt 51. . Thereafter, by reversing driving of the reversing belt 51, the transfer paper is reversely conveyed through the reversing guide section 50 to the intermediate tray section 53 and once docked.

Then, when the RDH 21 starts automatically feeding the next document onto the contact glass 20, the above-mentioned paper is conveyed to the pair of registration rollers 44 by the front shifting roller 54, the front shifting belt 55, and the paper refeeding roller 56. The paper enters a standby state and is fed to the photosensitive drum 31 with the other side facing up according to the transfer timing. When the document is transferred to the other side, the transfer paper is fixed by the fixing device 46 and then conveyed to the paper folding unit R via the discharge roller 47.

The paper folding unit R includes a conveyance row 557, a switching guide 58 to the paper folding side, a conveyance guide section 59, a stopper section 60.
Paper folding section 61, discharge guide section 62, and conveyance roller pair 63
etc. Then, the transfer paper conveyed through the discharge row 547 is conveyed to the stopper section 60 via the switching guide 58 and the conveyance guide section 59, and is temporarily held there. next,
The first half of the transfer paper in the transport direction is folded in half by the paper folding section 61 with left binding, and the transfer paper is transported to the stable unit S through the discharge guide section 62 and the transport roller pair 63.

The stapling unit S includes a switching guide 64, a discharge roller section 65, a shift tray 66, a paper alignment mechanism 67, a staple 68, a staple tray 69, and the like. The transfer paper conveyed through the pair of conveyance rollers 63 is then discharged to the shift tray 66 by the switching guide 64 or
It is switched whether the paper is transported to the paper alignment mechanism 67 or not. The transfer paper conveyed to the paper alignment mechanism 67 is stacked in the stack 6 for each copy.
After staples (binding needles) are inserted by 8, the paper is discharged to a staple tray 69.

Next, an example of a block configuration of a control system of the image forming apparatus will be described with reference to FIG.

The selection instruction section 1 outputs setting contents such as mixed loading mode, double-sided copy mode, etc. selected and instructed using an operation section (not shown) to the CPU 6 through the interface circuit 5. When the print key 2 is turned on, a start signal indicating the start of transfer is sent to the CPU through the interface circuit 5.
6. The resist drive unit 3 is a CPLI
6 through the interface circuit 5, the registration roller pair 44 is driven to feed paper to the photosensitive drum 31.

The drive unit 4 controls the RDH 21 and the optical system L based on a control signal input from the CPU 6 through the interface circuit 5.
1 retransmission mechanism Q, etc.

When the CPU 6 is set to the mixed loading mode and the double-sided copy mode, the CPU 6 drives the RDH 21 to pre-circulate the placed originals starting from the lowest original in order to make one round in advance, and detects the detection result from the original size sensor 219 during the preliminary circulation. It has a function of detecting the number of originals and the original size of each original according to the number of originals, and a function of storing the detected original size in correspondence with each original in the memory 7. Further, after the preliminary circulation, the CPL 16 transfers the transfer sheet corresponding to the large size document to the photoreceptor drum 31 from among the document sizes of both consecutive documents to be transferred to both sides of the transfer paper based on the memory result of the memory 7. It has a function to select which paper to feed, and a function to switch the feeding timing of the transfer paper as described later when the document to be transferred on both sides of the transfer paper is of small size or large size. That is, for example, if the originals are A4 size and then A3 size, the image forming means P is used when transferring the A4 size original so that the A4 size original is transferred to the latter half of the A3 size transfer paper.
The paper feeding timing is made earlier than the start of scanning by the optical system. In other words, scanning by the optical system is started when the second half of the A3 size transfer paper is fed from the refeeding mechanism Q to the photosensitive drum 31. Note that the first half of the A3 size transfer paper may be conveyed in advance and stopped, and the conveyance of the transfer paper may be resumed at the timing when the optical system starts scanning.

Furthermore, if both documents are A3 size or A4 size, the documents are transferred to both sides of the transfer paper as usual.

The memory 7 is composed of a RAM, etc., and stores the document size in association with each document.

Next, an example of the operation of the image forming apparatus will be described using the flowchart of FIG. 3. Note that this flowchart will be described assuming that A4 size and A3 size are mixed and the set magnification is 100%. Further, the originals are transferred sequentially from the lowest placed position. That is, the transfer is performed from the back side of the transfer paper.

After setting the desired magnification and setting the double-sided copy mode, when the print key 2 is turned on, the RDH 21 is driven and the originals mixed on the *RDH 21 are temporarily copied.
! The number of originals is circulated, the count value N indicating the number of originals is stored, and the original size of each original is detected according to the detection result of the original size sensor 219, and the detected original size is The original at the top is set as the first sheet, and the lowest original is replaced with the Nth sheet, and the originals are stored in the memory 7 in correspondence with each original (steps 81 to 84).

Next, it is determined whether the count value N is an odd number,
If the count value N is an odd number (YES in step S5)
, if the lowest (Nth) document is A4 size, A4 size transfer paper is selected, and if it is A3 size, A3 size transfer paper is selected, and this Nth document is the selected transfer paper. After being transferred to one side of the paper, the paper is discharged to the paper folding unit R as it is. If the transfer paper is A3 size, Z-folding is performed, and then 1 is subtracted from the count value N (N-N
-1) (Steps Ss, S; y, Sg).

Next, the document sizes of the Nth document after the subtraction and the N-1st document are compared, and if the sizes of both documents match (YES in step S9), that is, even if both documents are A4 size. For example, A4 size transfer paper is selected, while if A3 size, A3 size transfer paper is selected, and after the Nth original is transferred to the back side of the transfer paper, it is conveyed to the retransmission mechanism Q, and the Nth original is transferred to the retransmission mechanism Q. - The first document is transferred onto the surface of the transfer paper (step S10 to step 5t2).

After this, in step St1, 2 is subtracted from the count value N (N-N-2), and it is determined whether the count value N after the subtraction is O. If the count value N is O (step S% YES), since the transfer of all mixed documents has been completed, the transfer operation is completed and the documents are discharged to the paper folding unit R. On the other hand, if the count value N is not O (No in step Sw), the process returns to step S9 again.

Then, if the document sizes of the Nth document and the N-1st document do not match (NO in step S9), the sizes of these documents are compared, and the Nth document is determined as the N-1st document. If it is smaller than the size (YES in step S11), A3
The size of the transfer paper is selected, and the Nth original is printed as shown in Figure 4 (
As shown in the shaded area in FIG. The image is transferred to the first half (step 816 to step 81B).

Next, in step 81g, the count value N or 62 is subtracted (N-N-2>, and if the count value N is 0 (YES in step 820>), the transfer operation is completed and the paper is discharged to the folding unit R. Then, as shown in FIG. 4(C), the transfer paper is Z-folded by six-stitching.If the count value N is not O (NO in step S2o), the process returns to step S9 again.

On the other hand, if the size of the Nth sheet is larger than the size of the N-1st sheet (No in step Ss), A3 size transfer paper is selected, and the Nth sheet of the original is in the shaded area in FIG. 5(a). As shown in FIG.
- The first original is transferred onto the surface of the transfer paper as shown by the hatched area in FIG. 5(b), and 2 is subtracted from the count value N (N-N-2) (step S23. 324),
If the count value N is O (YES in step 825)
), the transfer operation is completed and the paper is discharged to the paper folding unit R.
As shown in FIG. 5(C), the transfer paper is Z-folded by left binding. On the other hand, if the count value N is not 0 (No in step S25), the process returns to step S8 again.

In this way, if the size of the Nth original is larger than the size of the N-1th original (NO in step StI), that is, for example, if the size of the 1st (N-1st) original is A4 size, If the second (Nth) document is in the order of A3 size, the A4 size document will be copied in the latter half of the conveyance direction of the transfer paper, so the paper folding will occur as shown in Figure 5 (C). Even if Z-folding is performed by unit R, the A4 size document after transfer will not be folded. Also, the first one (N-
If the first (first) document is A3 size and the second (Nth) document is A4 size, the A4 size document will be copied to the front half of the transfer paper in the transport direction as usual, so the Figure 4 (
As shown in C), even if Z-folding is performed by the paper folding unit R, the A4 size document will not be folded, as described above.

For example, even when B5 size and B4 size are mixed, the process in the above flowchart can be performed in the same way as when A4 size and A3 size are mixed.

Further, as the document size detection means, a plurality of light emitting elements and a light receiving element are provided below the contact glass 20 in association with each other, and the light receiving element detects the light emitted from the light emitting element to the document surface. The reflected light may also be detected.

That is, for example, one of the plurality of light-emitting and light-receiving elements is placed below the B4 original placement position in order to distinguish between B5 size and B4 size, and the other one is placed below the B-row size. In order to distinguish between the A size and the A3 size and A4 size, it is placed below the placement position of A4 originals other than the B row size. Then, the document size is identified based on the detection state of each light receiving element.

In the above description, Z-folding with left-hand binding was explained, but the present invention is also fully applicable to Z-folding with right-hand binding. In this case, if the document sizes to be transferred to both sides of the transfer paper are in the order of small size and large size,
What is necessary is to control the timing of the small size. For example, in the flowchart of FIG. 3, the magnitude relationship in step S15 may be reversed.

Further, the Z-folding is not limited to the paper folding unit R, and may be performed manually.

〔Effect of the invention〕

The present invention applies when the originals are right-bound and transferred to both sides of the transfer paper in the order of small size and then large size, or when the originals are left-bound and transferred to both sides of the transfer paper and are in the order of large size and then small size. When transferring a small-sized original, the timing of feeding the paper to the image forming means is advanced relative to the start of scanning by the optical system, so even if Z-folding is performed as paper folding in post-processing, the transferred portion of the small-sized original is By folding the document in half, the document is not folded in, making it easier to read the document and improving its appearance.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a control system of an image forming apparatus according to the invention, FIG. 2 is a schematic configuration diagram showing an example of an image forming apparatus according to the invention, and FIG. 3 is an image forming apparatus according to the invention. Flowcharts showing an example of the operation of the device, FIGS. 4 and 5
The figure is a diagram for explaining the operation of the image forming apparatus according to the present invention, and FIGS. 6(a) and 6(b) are diagrams for explaining the conventional problems. 1... Selection instruction section, 2... Print key, 3...
resist drive section, 4... drive section, 5... interface circuit, 6... CPU, 7... memory, 21.
... Circulating automatic document feeder (RDH), 44... Registration roller pair, 219... Original size sensor, L...
...optical system, P...image forming means, Q...retransmission mechanism,
R...Paper folding unit, S...Stapling unit. Patent applicant: Mita Kogyo Co., Ltd. Representative: Patent attorney: Etsushi Kotani
Patent Attorney Chief 1) Masamukai Patent Attorney 9 Takao Fuji

Claims (1)

[Claims] 1. A circulating automatic document feeder that automatically feeds large and small size documents, an image forming device that scans with an optical system to form an image, and a single-sided document feeder that transfers the document onto both sides of the fed transfer paper. In the image forming apparatus, the image forming apparatus has a refeeding function for refeeding the transferred paper to the image forming means, a preliminary feeding means for prefeeding the document, and a document size of each document at the time of the preliminary feeding. A detection means for detecting, a storage means for storing the detected original size, and a transfer paper selection for selecting a transfer paper corresponding to a large size among the original sizes of the original to be transferred on both sides of the transfer paper. If the document is right-bound and transferred to both sides of the transfer paper in the order of small size and then large size, or if the document is left-bound and transferred to both sides of the transfer paper is in the order of large size and then small size. timing control means for advancing the timing of paper feeding to the image forming means relative to the start of scanning of the optical system when transferring the small size original in order to transfer the large size original to the rear half side of the transfer paper; An image forming apparatus characterized by: