JPH09297435A - Image forming device provided with automatic document feeding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve productivity for image-forming by quickening the detection timing of the existence of a next document by providing an exclusive detecting means for detecting the existence of the next document independently of a document set detecting means. SOLUTION: Document existence sensors 212(S1), 213(S2) and 214(S3) constituted of reflection type photosensors are disposed at a position right under the upper surface of a document platen 201, and when a document is set on the document platen 201, the document is detected by reflected light. Respective document existence sensors 212(S1), 213(S2) and 214(S3) are arranged in respectively different feeding directions so as to detect the documents whose sized are different. Next document detecting is performed by making a control part check the respective signals of a document setting means 211 or the document existence sensors 212(S1), 213(S2) and 214(S3) after the lapse of specified time at a timer started by document feeding start.

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 such as a copying machine or a printer, and more particularly to a time required for feeding an original fed to a reading position by an automatic original feeding apparatus and a transfer sheet feeding apparatus. An automatic document feeder that prevents the document feed waiting time that occurs due to the difference between the time required to feed from the tray to the image forming unit and the resulting reduction in the operating rate of the device. The present invention relates to an image forming apparatus including.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus equipped with an automatic document feeder, the originals set on a document table of the automatic document feeder are taken out one by one and the contact glass of the image forming apparatus is used. The time required to feed the image to the reading position (exposure position), the time required to read the image, and the amount of time to feed the transfer sheet from the paper feed tray equipped in the image forming apparatus to the image forming unit (transfer position). In consideration of the difference in required time, the document feeding timing or the paper feeding timing from the paper feeding tray is set so that the image formation is completed in the shortest time. By the way, when making a plurality of copies from one original, since the number of copies is known in advance, it is possible to appropriately set the feeding timing of each original or each transfer sheet. When copying (copy each manuscript 1
If you want to make a copy, check whether or not the next original should be fed after determining whether or not the next one should be fed after a certain original is fed, read, and image is formed on the corresponding transfer. I cannot judge unless I do. Japanese Patent Application Laid-Open Nos. 2-113267 and 3-154075 disclose techniques for controlling the timing of starting document feeding in order to improve productivity during copying. That is, in Japanese Unexamined Patent Publication No. 2-113267, the timing of feeding the first original to the reading position and then feeding the second original to the reading position is set to a predetermined value so that the second original is fed. A technique for shortening the waiting time for starting paper feeding and increasing productivity is disclosed. JP Hei 3
According to Japanese Patent Laid-Open No. 154075, the presence or absence of a next original is detected at the time of feeding the original, and when the next original is present, the feeding operation of the next transfer sheet is started at a predetermined early timing.
Techniques for improving productivity by eliminating waiting time have been disclosed. In order to enable such control, in addition to the document set detection function that detects that a document is set on the platen, it is necessary to have a function that detects the presence or absence of the next document. The presence or absence of the next original is also detected by the original set detecting means.

[0003]

As in the above-described conventional example, an automatic document is taken out one by one from a document stack set on a document table of an automatic document feeder and is fed to a document reading position. The feeding device has a document set detecting means for detecting that a document is set, and the document set detecting means has a function of detecting the presence or absence of the next document after the document is conveyed. That is, if the original set detection means is still ON even after the trailing edge of the preceding original has completed passing through the original set detection means, it is determined that the next original is set. . However, in the conventional automatic document feeder, since the presence or absence of the next document is detected by using only the document set detection means, the control unit sets the trailing end of the document to the original after the feeding of the preceding document is started. It was not possible to determine the presence or absence of the next original until the completion of passing through the set detection means. Whether or not the trailing edge of the preceding document has completely passed through the document setting detection means is detected by the passage detection means located further downstream. For this reason, 1 to 1 is required by using the automatic document feeder.
When making a copy, a waiting time is inevitable at the document feeding timing, and there is a limit to improvement in productivity. The present invention has been made in view of the above, and the invention of claim 1 provides a detection unit dedicated to detecting the presence or absence of the next original document in addition to the document set detection unit, thereby detecting the presence or absence of the next original document. The purpose is to speed up the process and increase productivity in image formation. According to the invention of claim 2, the document size,
The purpose of the present invention is to implement optimum control by selecting and switching the detection means used as the next original detection means according to conditions such as the position of the paper feed tray and the number of copies. According to the third aspect of the present invention, the detection means for detecting the presence or absence of the next original can be fixedly switched to the original set detection means, thereby performing control according to the method of feeding the original or the method of operation. The purpose is to enable and improve operability.

[0004]

In order to achieve the above object, the invention of claim 1 is an automatic document feeder provided in an image forming apparatus, and a plurality of documents can be set in a stacked state. A document table, a sheet feeding device for taking out and feeding the documents on the document table one by one, a conveying device for conveying one taken-out document to a reading position on the image forming apparatus side, and a document table on the document table. A document set detection means arranged upstream of the document table to detect that the document is set, and a document set detection means is provided on the document table to detect the presence or absence of the document on the document table. As a plurality of manuscript presence / absence detecting means arranged along the paper direction, and as a next manuscript detecting means for detecting the existence of a manuscript to be fed next after feeding one manuscript on the manuscript table,
A control unit for selectively selecting one of the document set detection unit and the document presence / absence detection unit is provided, and the control unit detects the presence / absence of a next document by using the selected detection unit. And According to a second aspect of the present invention, in the image forming apparatus, the image forming unit records an original image read at the exposure position on a transfer sheet, and a plurality of sheet feeding units for storing the transfer sheet fed to the image forming unit. A tray and a transfer sheet conveying unit that conveys a transfer sheet from each sheet feeding tray to the image forming unit. The control unit selects the next document detecting unit to set the selected sheet feeding tray and the document table. It is characterized in that it is performed based on the size of the original document and the data about the number of copies for setting how many copies are made from one original document. According to a third aspect of the present invention, there is provided an instruction means for switching and fixing the selection of the next original detection means by the control portion to the original set detection means, and the next original detection means detects the original set by the input from the instruction means. It is characterized by being fixed to the means.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to the embodiments shown in the drawings. 1A and 1B are an overall configuration diagram of an example of an image forming apparatus of the present invention and a structural diagram of an automatic document feeder. An automatic document feeder ARDF (Auto Reverse Document Feeder) B is installed on the image forming apparatus A, and a mass paper feeder C is arranged along one side wall of the image forming apparatus. Automatic document feeder (ARD
F) B is composed of a document feeding section B-1 and a document feeding section B-2, and the document feeding section B-1 has a document table 201 on which a document bundle to be read is set. The originals placed on the original table are original call rollers 202a, 2a.
When the original separating roller 203 and the original separating blade 204 operate, only one original document at the bottom is pulled out by the rotation of the paper 02b.
reaches b. Rollers 202a, 202b, 203, 2
05a, 205b, the blade 204 and the like constitute a document feeding means.

After that, the original is conveyed to a reading position (exposure position) on the contact glass 101 by an original conveying belt (original conveying means) (not shown) which constitutes the original conveying section B-2. A document that has been stopped at the reading position is
It is illuminated by the fluorescent lamp 102. The reflected light from the document is transferred to the photosensitive belt 107 by the first mirror 103, the second mirror 104, the through lens 105, and the second mirror 106.
It is guided to the top and exposed. The surface of the photoconductor belt 107 is
Electric charges are uniformly applied by the charger 108, and an electrostatic latent image is formed by the exposure of the reflected light of the document. The electrostatic latent image on the photosensitive belt 107 has its unnecessary portion removed by the eraser 109, is developed by the developing device 110, and is sent to the transfer portion 111. The developed document image is transferred onto the transfer paper by the transfer charger that constitutes the transfer unit 111. This transfer paper is used for the paper feed trays 112, 113,
The paper is fed from any one of 114, the auxiliary paper feed tray 150, and the double-sided tray 124, and a conveyance path (transfer paper conveyance means) 115.
The image is conveyed along the sheet and is sent between the photosensitive belt 107 and the transfer charger 111 by the registration roller 116 in time with the original image on the photosensitive belt 107. The transfer paper on which the image is transferred is separated by the charger.
It is separated from the photoconductor by 120, passes through the conveyor belt 117, enters the fixing device 118, and is fixed there.

In the double-sided mode of copying on both sides of the transfer paper,
The double-sided switching claw 121 switches the conveyance path to the double-sided tray 124 side, the transfer paper is sent to the double-sided tray 124 from the double-sided entrance path 123, and is temporarily stored in the double-sided tray. In the single-sided mode in which only one side of the transfer paper is copied, the double-sided switching claw 121 is switched to the paper discharge side, and the paper is discharged to the paper discharge unit 1.
Discharged on 30. After the transfer paper is separated, the photoconductor belt 107 is destaticized by the destaticizing charger-125, and the cleaning device 126 removes the residual toner on the photoconductor to prepare for the next copying.

Next, referring to FIG. 1 (b), the construction of an example of the document feeding section B-1 which is a main part of the present invention will be described. The characteristic configuration of this embodiment is the presence / absence detecting means 212 (S) for detecting the presence / absence of a document directly below the upper surface of the document table 201.
1) 213 (S2) and 214 (S3) are arranged to detect a document for each size (length in the feeding direction) and to detect the presence or absence of the next document using these sensors. It is in. When the document bundle D is set on the document table 201 and the leading end of the document bundle D enters the document feeder B-1, the document set filler-210 located inside is pushed upward by the document D, and the document set filler-210. The document set detecting means 211 which has detected the detection of the document detects that the document is set (FIG. 2). The document set detecting means 211 is composed of a photo interrupter or the like, and when the document D does not exist on the document table, the tip of the filler 210 falls into the hole formed in the document table and the document set detecting means 211 is turned off. On the other hand, when the document is set, the hole is closed by the document, so that the leading end of the document set detection filler 210 is lifted above the document, and the document set detection means 21.
Turn 1 on. As described above, the document presence / absence sensors 212 (S1), 213 (S2), 214 (S3), which are reflection type photosensors, are arranged (embedded) just below the upper surface of the document table 201. When a document is set on, the document is detected by the reflected light.

The respective document presence / absence sensors are arranged at different positions in the feeding direction so as to detect documents of different sizes. The document sizes detected by each sensor are as shown in the table below. FIG. 3 is a timing chart of the sensor signal when the final document is conveyed. Here, the document size is A4 (i).
And A3 (ii). If the document size shown in (i) is A4, the trailing edge of the A4 size document is detected by the sensor S2 after the time t ₂ has elapsed after the start of feeding.
To pass through, and OFF first sensor S2, then over time t _1, the sensor S1 is turned OFF, turning OFF the document set detection means 210 and 211 with the lapse of the last time t _S. When the document size shown in (ii) is A3, the sensor S3 is first turned on by the document setting, and then the sensors S2 and S1 are sequentially turned off as the document feeding progresses. Finally, when the time t _S has elapsed, the document set detecting means 2
11 (210) is turned off. The detection of the next original is performed by the control unit checking each signal of the original set detection means 211 or the original presence / absence sensors S1, S2, S3 after a predetermined time elapses by a timer started by the start of feeding the original. This operation will be described later. In addition, the detection of the document size is
The output voltage of the slide VR (variable resistor) 300 that interlocks with the movement of the side fence 201a on the document table 201 is AD.
It is done by converting. That is, the slide VR3 is set by setting the side fence 201a supported so as to be able to advance and retreat in the width direction orthogonal to the paper feeding direction according to the width of the document.
Since the resistance value of 00 changes, the voltage output from the power supply line through the slide VR 300 changes. The capacitor 301 prevents fluctuations in voltage when the resistance value of the slide VR changes abruptly, and removes noise. The buffer 302 amplifies the voltage with an amplification factor of 1 and outputs it to the A / D converter 303.

Next, FIG. 5 is a timing chart of a copying operation when ARDF is used, and this timing chart will be described below. First, FIG. 5 (i) is a copy sequence for copying the first original, which shows the timing of paper feed from each paper feed tray, the timing of original feed by ARDF, and the image forming unit. FIG. 6 is a diagram showing a relationship with exposure start timing in the reading optical system of FIG. The feeding of the first transfer sheet from the auxiliary tray 150 and the double-sided tray 124 needs to be performed prior to the feeding of the corresponding original document, while the feeding from the other trays 114, 113, and 112 is performed. The paper timing will be set after the document is fed. FIG. 5 (ii) shows the timing of the sequence for continuously executing the copy of the second sheet, and (iii) (iv) is a sequence diagram for executing the copy of the third and fourth sheets, respectively. . To make continuous copies with high productivity, use 2 as shown by the dotted line.
The timing (T4) at which the first transfer sheet is fed from the auxiliary tray 150 is set to the time (T4) at which the first original is fed.
It is necessary to set it earlier than 2), but if it depends only on the document set detection means 211 (210), the presence or absence of the second document cannot be determined at that time (T4) as described above. That is, since it is detected that the trailing edge of the first document has passed the document set detection means 211, and the detection means 211 still detects the presence of the document, it is determined that the next document exists. At the time of T4, it cannot be determined that the next original exists. Therefore, the second copy
It is necessary to delay the start of the can until the presence or absence of the next original is detected, which causes the productivity in 1 to 1 copying to be delayed.

That is, in the image forming apparatus of the present invention, the transfer paper is started to be transferred prior to the document feeding due to the difference in the transfer paper transfer path (distance from each paper feed tray to the image forming portion). It has a paper feed tray (auxiliary paper feed tray) that must be used. When a transfer sheet is fed from such a remote paper feed tray to form a 1 to 1 image, it is necessary to detect the presence or absence of the next original document before feeding the next transfer sheet. Otherwise, the result is that the transfer paper is fed but there is no corresponding document, and extra transfer paper is wasted. To prevent this, it is necessary to start feeding the transfer paper only after the presence of the next original is detected.
If the waiting time is secured in this way in the conventional apparatus, the second transfer sheet has to be fed at the time when it is significantly delayed from the original feeding timing (T4) for improving the productivity. Therefore, when using the auxiliary paper feed tray having such a relationship, detecting the presence or absence of the next original as soon as possible improves the productivity of the copying operation.

On the other hand, when a plurality of copies are made from one original, the presence or absence of the next original is detected even when the auxiliary paper feed tray having the above relationship is used. It is clear from the timing chart of FIG. 5 that it is not necessary to use the above-mentioned document presence / absence detecting sensors S1, S2, S3 as the next document detecting means. That is, for example, when making two copies from one original, the presence or absence of the second original is detected by the original set detection means 211 at the time when the original is completely fed for the first copy. Therefore, the document presence / absence detection sensor on the document table becomes unnecessary. Further, when re-feeding from the double-sided tray in double-sided copying, it is clear that at least two originals are present, so the second original is definitely fed, and therefore, the second original is fed. Even if the timing of feeding the first transfer sheet from the double-sided tray 124 is set sufficiently early, image formation is always performed and the transfer sheet is not wasted.

It should be noted that, in the present embodiment, whether or not the document presence / absence detection sensors S1, S2, S3 are used or the document set detection means 211 (210) is used to detect the presence or absence of the next document. Can be selected, and in the following cases, it suffices to detect the presence or absence of the next original using the original set detection means. That is, 1. When making two or more copies from the same original. 2. When using a paper other than the auxiliary paper feed tray as the transfer paper feeding means. In cases other than the above (in the case of 1 to 1 copy mode), the document presence / absence detection means (sensors S1, S2, S3,
By detecting the presence / absence of the next original, the productivity can be improved. In the 1 to 1 copy mode, the original set detection means 21 is used as the next original detection means.
It is clear from the configuration that 1 (210) is more reliable, so if it can be used without sacrificing productivity, it is more reliable to use this detection means first. Control becomes possible. Note that the control unit (CPU, ROM, RAM, etc.) (not shown) executes selection, switching, and other various controls of the next original detection unit based on various detection signals.

Next, FIGS. 6 and 7 are flow charts showing the operation for executing this selection and switching. First, in step 1, it is checked whether or not document feeding is started. If feeding is started, in step 2 the number of copies (copy number) is "
1 ", it is checked in step 3 whether the paper feed tray used at that time is the auxiliary tray 150, and if it is the auxiliary tray, the next original presence / absence detection is performed for each original size. After determining the sensor to be used, the time required for detecting the presence or absence of the next original corresponding to the determined sensor is determined (ST4 to ST17), and then the timer is activated to start execution of the next original detection control (ST18). , 19). Here, the size of the original document is the position information of the side fence shown in FIG.
The control unit can make a determination based on the detection signals from sensors 3 and 214 (sensors S1, S2, and S3).

Next, as shown in FIG. 7, when the timer measurement is started (ST30, 31) and the time determined above has elapsed, the determined sensor signal is read and O
N / OFF is checked (ST39), and the presence or absence of the next original is determined depending on the situation. That is, if the sensor (S3 or S2 or S1) is turned off after the lapse of the above time, there is no next original (ST41), and if it is on, the next original is present (S41).
T40) is determined. As a result, it is possible to quickly determine the presence or absence of the next original, and it is possible to start feeding the second transfer sheet from the auxiliary feed tray before feeding the first original. As the next original detection means, the original set detection means 21
An example of the case where it is necessary to use 1 is when using an irregular original. In this case, since the OFF timing of the document presence / absence sensor on the document table changes, the switching by the timer means as described in the above flowchart cannot be executed.
In such a case, the setting of the next original is made to be the original set detecting means by operating the instruction means (SW, key, etc. on the operation unit (not shown)) for selecting the original set detecting means as the next original presence / absence detecting means. Can (ST21YE
S). When the original set detection means is used as the next original detection means, the sensors S1, S2, S3 ...
Needless to say, is left inactive. In addition to the above, as the next original detecting means, the original set detecting means 2 is used.
As a case where it is necessary to use 11 (210), there is a case where manual feeding is performed from the document table 201. In this case, the sensors S1, S2, S on the document table are
When 3, ... Are kept in an operating state, erroneous detections such as manual operation or originals turning on or off the respective sensors S1, S2, S3 occur frequently, so the original set detecting means is exclusively used. Is preferred.

[0016]

As described above, according to the first aspect of the invention, in addition to the original set detecting means, the dedicated detecting means for directly detecting the presence or absence of the next original on the original table is provided. The detection time can be advanced and the productivity in image formation can be improved. According to the second aspect of the present invention, optimum control can be performed by selecting and switching the detection means used as the next original detection means according to conditions such as the size of the original, the position of the paper feed tray, and the number of copies. According to the third aspect of the invention, the detecting means for detecting the presence or absence of the next original can be fixedly switched to the original set detecting means. Therefore, control according to the method of feeding the original or the method of operation is possible. age,
Operability can be improved.

[Brief description of drawings]

1A and 1B are an overall configuration diagram of an example of an image forming apparatus of the present invention and a structural diagram of an automatic document feeder.

FIG. 2 is a configuration diagram of an example of a document set detection unit.

3 (i) and (ii) are diagrams showing timings at which a document presence / absence detection unit detects a document by size.

FIGS. 4A and 4B are circuit diagrams showing an example of a side fence and a document size detecting unit using the side fence.

5 (i), (ii), (iii), and (iv) are timing charts showing the relationship between the paper feed timing from each paper feed tray and the document feed timing.

FIG. 6 is a flowchart showing the main operation of the present invention.

FIG. 7 is a flowchart for explaining an operation for presence / absence of a next original document by each sensor constituting the original document presence / absence detecting unit.

[Explanation of symbols]

A image forming apparatus, B automatic document feeder ARDF, B
-1 Document Feeding Unit, B-2 Document Feeding Unit, C Mass Feeding Device, 101 Contact Glass, 201 Document Plate,
102 Fluorescent lamp, 103 1st mirror, 104 2nd mirror, 105 Through lens, 106 2nd mirror, 1
07 photoconductor belt, 108 charger, 109 eraser
Service, 110 developing device, 111 transfer part, 112 11
3, 114 paper feed trays, 115 conveyance paths (transfer paper conveyance means), 124 double-sided trays, 150 auxiliary paper feed trays, 2
01 manuscript table, 202a, 202b manuscript call roller,
203 original separation roller, 204 original separation blade,
205a, 205b Pull-out roller, 210 Document set filler, 211 Document set detection means, 21
2, 213, 214 Document presence / absence detection means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Masuyama 1-3-6 Nakamagome, Ota-ku, Tokyo Within Ricoh Co., Ltd. (72) Inventor Yoko Fukui 1-3-6 Nakamagome, Ota-ku, Tokyo Shares Inside the Ricoh Company (72) Inventor Nobuaki Tomisho 1-3-6 Nakamagome, Ota-ku, Tokyo Within Ricoh Co., Ltd. (72) Inventor Kunio Hayakawa 1-3-6 Nakamagome, Ota-ku, Tokyo In-house Ricoh Company

Claims (3)

[Claims] 1. An automatic document feeder provided in an image forming apparatus, comprising a document table on which a plurality of documents can be stacked and a document on the document table is taken out and fed one by one. Paper feeding means, conveying means for conveying one taken-out document to a reading position on the image forming apparatus side, and an upstream side of the document table for detecting that the document is set on the document table. A plurality of document presence / absence detection means arranged along the paper feeding direction on the document table to detect the presence / absence of a document on the document table; As a next document detecting unit that detects the presence or absence of a document to be fed next after feeding one of the above documents, a control unit that selectively selects one of the document set detecting unit and the document presence detecting unit. , And the control unit is one of the selected An image forming apparatus equipped with an automatic document feeder, which detects the presence or absence of a next document by using the above-mentioned detecting means. 2. The image forming apparatus comprises: an image forming section for recording a document image read at the exposure position on a transfer sheet; and a plurality of sheet feeding trays for storing the transfer sheet to be fed to the image forming section. And a transfer sheet conveying unit that conveys the transfer sheet from each sheet feeding tray to the image forming unit. The selection of the next document detecting unit by the control unit is set on the selected sheet feeding tray and the document table. An image forming apparatus provided with an automatic document feeder, which is performed based on a size of a document and data on a number of copies for setting how many copies are made from one document. 3. An instruction means for switching and fixing the selection of the next original detection means by the control section to the original set detection means is provided, and the next original detection means becomes the original set detection means by an input from the instruction means. An image forming apparatus having an automatic document feeder, which is fixed.