JP2015003781A - Automatic document feeding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the frequency and volume of ambient noise caused by the transport assist of a document by a resister roller.SOLUTION: An automatic document feeding device comprises: a resister roller 14; a read sensor S3; a sheet discharge inversion roller 18 for transporting, toward the register roller 14, a document D which has been turned upside down after the image reading of an image on a first page and which can contact and separate from the register roller 14; and a control part 50 for controlling the register roller 14 and the sheet discharge inversion roller 18 on the basis of the output of the read sensor S3. The control part 50 starts the separation of the sheet discharge inversion roller 18 after the start of the rotation of the register roller 14, in the image reading of an image on a second page, and when the read sensor S3 does not detect the document D within a first predetermined time, brings the sheet discharge inversion roller 18 into contact with the document D for starting transport assist.

Description

  The present invention relates to an automatic document feeder that transports a document to an image reading position, reverses the document after image reading, and transports the document to the image reading position again.

  Conventionally, in a sheet reversing device of a copying machine, the jam detection timing at the time of sheet ejection or reversal can be varied as a countermeasure for conveyance failure depending on the sheet type when the sheet is ejected or reversed. Is known (for example, see Patent Document 1). For example, a sheet having a large size such as A3 having a large friction with the conveyance path reduces the sheet conveyance failure by delaying the jam detection timing.

  Further, in an automatic document feeder capable of reversing the front and back, in order to assist the conveyance of the document by the registration roller, the document may be pushed back (conveyance assist) by an upstream roller, for example, a reversal roller. If the original was thick paper or curled paper, even if the front end of the original hits the roller and the registration roller rotates when the original is applied to the registration roller in preparation for image reading on the back side of the original, May not be transported. In such a case, the conveying force of the document, which was not sufficient with only the registration rollers, is increased by rotating the document by contacting it with the reverse roller on the upstream side.

Japanese Patent Laid-Open No. 6-1515

  However, there is a problem that the frequency and magnitude of noise increase when carrying assist is performed. That is, the conveyance assist is performed by reversing the motor that is the driving source of the reversing roller, and further bringing the reversing roller into contact with a shortened solenoid or the like. When the conveyance assist is performed, the number of times the motor is started, reversely rotated, and stopped is increased by one as compared with the case where the conveyance assist is not performed, and the frequency of noise by the motor increases accordingly. Further, the conveyance assist is performed by contacting the reversing roller. However, when the conveyance assist is performed, it is not possible to perform the separation, and the solenoid needs to be shortened in a short time. For this reason, an operation sound becomes louder than the case where there is no conveyance assistance. As described above, when the conveyance assist is performed, the frequency and the magnitude of the noise are increased as compared with the case where the conveyance assist is not performed.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic document feeder that reduces the frequency and magnitude of noise associated with document conveyance assistance by registration rollers.

  The automatic document feeder of the present invention conveys a document set on a document placement unit to an image reading position, reverses the document after reading the image on the first side, and reads it again for image reading on the second side. A registration roller configured to convey to the image reading position, temporarily stopping the document conveyed from the document placement unit, and then rotating the document toward the image reading position; and the registration roller; An original detection sensor disposed between the image reading position, a reversing roller capable of moving toward and away from the first and second originals after image reading on the first side, and a registration roller; And a controller that performs control of the reversing roller based on the output of the document detection sensor, and the control unit performs the reversal after starting the rotation of the registration roller when reading the second image. When the document detection sensor does not detect the document within a first predetermined time after starting the separation of the roller, the reversing roller is brought into contact with the document to start conveyance assist. Yes.

  The automatic document feeder of the present invention starts the conveyance assist for a document when it does not detect the document within the first predetermined time when reading the second image, and detects the document within the first predetermined time. In this case, the conveyance assist is not performed for the document. In other words, the conveyance assist is performed only for a document that is not normally conveyed (hereinafter referred to as “non-feed” as appropriate), and the conveyance assist is not performed for a document that is normally conveyed. Can be minimal. Thereby, the frequency and magnitude | size of a noise accompanying conveyance assistance can be reduced.

FIG. 2 is a front view showing a configuration of an automatic document feeder. FIG. 2 is a block diagram showing a control configuration of the automatic document feeder in FIG. 1. 3 is a flowchart for explaining the operation of the automatic document feeder in FIG. 1.

  Hereinafter, an automatic document feeder according to an embodiment of the present invention will be described with reference to FIGS. Among these, FIG. 1 is a front view showing a configuration of an automatic document feeder. The front means the side on which the user is located when operating the automatic document feeder. FIG. 2 is a block diagram showing a control configuration of the automatic document feeder shown in FIG. FIG. 3 is a flowchart for explaining the operation of the automatic document feeder shown in FIG.

  As shown in FIG. 1, the automatic document feeder 1 includes a document placement tray (document placement portion) T1, a transport path P1, and an upstream side along the transport direction (arrow K1 direction) of the document D. A paper discharge tray T2 is provided. The automatic document feeder 1 also includes a transport path P2 that connects the vicinity of the downstream end and the vicinity of the upstream end of the transport path P1.

  Among these, the document placing tray T1 is gently inclined so that the downstream side near the conveyance path P1 is positioned below, and a plurality of documents D on which images are read are set in a stacked state. The set document D is positioned at a feeding position (not shown) by a positioning member (not shown) at the front end (downstream end) and the side end. The document D placed on the document placement tray T1 is placed with the surface having the image to be read facing upward. In addition, when there are images to be read on both the front and back surfaces (one surface and two surfaces), the image is placed with the one surface read first facing upward.

  The conveyance path P1 guides the document D fed from the document placement tray T1 to a flow reading glass (image reading position) G by making a U-turn in a semicircular shape. And is guided to the paper discharge tray T2. The conveyance path P2 branches at a branch point B1 in the vicinity of the paper discharge tray T2 in the conveyance path P1, and enters the conveyance path P1 at a merging point B2 in the vicinity of the document placing tray T1 in the conveyance path P1 and before a registration roller 14 described later. Have joined. As will be described later, the conveyance path P <b> 2 guides the document D that has been read from one side and turned upside down to the registration roller 14.

  The automatic document feeder 1 is provided with a plurality of rollers and the like for feeding and conveying the document D. A pickup roller 11 is disposed above the downstream end side of the document placing tray T1. Further, in order from the upstream side to the downstream side along the conveyance path P1, the separation roller 12, the separation pad 13, the registration roller 14, the conveyance roller 15, the pressing roller 16, the conveyance roller 17, and a paper discharge reversing roller (contact and separation) ( A reverse roller 18 is provided. The separation roller 12, together with the separation pad 13, separates one sheet from the plurality of documents D and conveys it to the registration roller 14. The registration roller 14 performs registration of the document D by contacting the leading end of the document D conveyed to the nip portion when the registration roller 14 is stopped. The conveyance roller 15 conveys the document D conveyed from the registration roller 14 to the flow reading glass G. The pressing roller 16 presses the document D against the reading glass G. The transport roller 17 transports the document D after image reading toward the paper discharge reverse roller 18. The paper discharge reversing roller 18 discharges the document D for which image reading has been completed onto the paper discharge tray T2 by rotating it in the counterclockwise direction in FIG. Further, when the image reading on the first side of the document D is completed and the image reading on the second side is performed, the document D is conveyed toward the registration roller 14 in the clockwise direction in FIG. .

  FIG. 2 is a block diagram showing the internal configuration of the document conveying device of the present invention. The automatic document feeder 1 includes a CPU (control unit) 50 that controls the overall operation. A RAM 51, ROM 52, communication I / F 53, solenoid SL, image reading unit 54, image processing unit 55, and separation clutch C 1 are connected to the CPU 50 via a system bus 56. Further, the document presence / absence sensor S0, the separation motor M1, the read motor M2, the registration sensor (registration sensor) S2, the read sensor (document detection sensor) S3, the paper discharge sensor S4, and the registration clutch (registration clutch) are also transmitted via the system bus 56. ) C2 is connected.

  Among these, the RAM 51 is a work area for the CPU 50 and a temporary storage area for data. The ROM 52 is written with a firmware program for driving the automatic document feeder 1 and a boot program for controlling the firmware program, and these are used by the CPU 50. The communication I / F 53 is connected to a system controller or the like, through which an instruction for document conveyance, image data, or the like is transferred. The solenoid SL is for contacting and separating (contacting / separating) the paper discharge reversing roller 18 (see FIG. 1). The image reading unit 54 optically reads an image of the conveyed document D, performs image processing such as image determination and image correction by the image processing unit 55, and outputs the image to the system controller or the like via the communication I / F 53 described above. can do. The image processing unit 55 includes a printing rate calculation unit that calculates a printing rate of an image read by the flow reading glass G, and whether or not the printing rate calculated by the printing rate calculation unit is equal to or higher than a predetermined printing rate. And a printing rate judging means for judging.

  The separation clutch C <b> 1 connects and disconnects the rotation of the separation motor M <b> 1 with respect to the separation roller 12 and the pickup roller 11. That is, the separation roller 12 and the pickup roller 11 are configured to stop the document conveyance operation for conveying the document when the separation clutch C1 is operated and the separation motor M1 is not subjected to the rotational force (document conveyance operation). Can be stopped). The separation roller 12 and the pickup roller 11 can be brought into contact with and separated from the document by a plunger (not shown), and the document conveying operation is stopped even when the plunger is operated and separated from the document. . The document presence / absence sensor S0 detects the presence / absence of the document D set on the document placement tray T1. The document size detection sensor S1 detects the size of the document D (for example, A4 size, B4 size, A3 size, etc.). The read motor M2 rotates and drives the registration roller 14, the conveyance roller 15, and the conveyance roller 17. The registration sensor (registration sensor) S <b> 2 is disposed immediately upstream of the registration roller 14 and detects the document D conveyed to the registration roller 14. The read sensor S <b> 3 is disposed immediately upstream of the transport roller 15 and detects the document D transported to the transport roller 15. The paper discharge sensor S4 is arranged on the upstream side of the branch point B1, and detects the original D on which the image is read by the flow reading glass G. The registration clutch C <b> 2 connects and disconnects the rotation of the separation motor M <b> 1 with respect to the registration roller 14.

  FIG. 3 is a flowchart for explaining the operation of the automatic document feeder 1. The operation of the automatic document feeder 1 when reading images formed on one side (front side) and two sides (back side) of the document D will be described with reference to FIGS. .

  First, the CPU 50 counts the number of sheets fed of the document D to determine whether it is the first sheet (S301). If it is determined to be the first sheet (YES in S301), the conveyance assist flag on the RAM 51 is reset. (To zero) (S302). Next, the document D is fed by the pickup roller 11 and the separation roller 12 (S303), and the leading edge of the document D is brought into contact with the nip portion of the resist roller 14 that has been stopped to temporarily stop the registration. Thereafter, the registration roller 14 is rotated again to start conveyance of the document D (registration conveyance) (S304).

  Here, it is determined whether or not the leading edge of the document D is detected by the lead sensor (lead S) S3 (S305). If the leading edge of the document D cannot be detected within the second predetermined time after the re-rotation of the registration roller 14 (NO in S305), it is determined that the document D remains in the vicinity of the registration roller 14, The separation roller 12 is rotated for a predetermined time to assist the conveyance of the document D. Then, the conveyance assist flag on the RAM 51 is set to 1 (S307).

  Next, the image reading unit 54 reads an image on the first side of the document D, that is, scans the front side (S308), and further, the document D is forwardly rotated by the transport roller 17 and the paper discharge reverse roller 18 to be discharged from the paper discharge tray T2. Transport toward Before the trailing edge of the document D passes through the branch point B1 and finishes passing through the paper discharge reverse roller, the paper discharge reverse roller is stopped and the switching member of the branch point B1 is switched. Further, the paper discharge reversing roller is reversed to invert the original D, and is conveyed in the direction of the arrow K2 toward the registration roller 14 along the conveyance path P2. At this time, the leading edge and the trailing edge of the document D are reversed. Then, the front end of the document D is brought into contact with the nip portion of the registration roller 14 (registration abutting) and stopped (S309).

  Next, the registration roller 14 is rotated again to start conveyance (registration conveyance) for reading the image on the second side of the document D (S310). Here, the state of the conveyance assist flag on the RAM 51 is determined (S311). When the conveyance assist flag is 1 (YES in S311), conveyance assist is performed. That is, in this case, it is determined that the document D is likely to cause non-feed by the registration roller 14, and the discharge reverse roller 18 is driven reversely for a predetermined time by the read motor M2 (S315). Assist. In this case, the conveyance assist is performed from the beginning without detecting the document by the read sensor, so that the detection time is omitted compared with the case where the conveyance assist is performed after the non-feed is detected. It is possible to improve the performance.

  Further, the discharge reversing roller 18 is separated by the solenoid SL. As a result, the paper discharge reversing roller 18 rotates idly so that the leading end side of the document D can pass through the paper discharge reversing roller 18. At this time, the solenoid SL gradually performs suction by current control (S316). This suppresses the generation of sound due to the impact of the mechanism when the paper discharge reversing roller 18 is separated.

  On the other hand, when the conveyance assist flag is 0 (NO in S311), the process proceeds to the next step, and the image processing unit 55 determines the duty (printing rate) of the image read by the image reading unit 54 (S312). If the image duty (printing rate) is equal to or greater than the predetermined value (YES in S312), it is determined that the document D is likely to cause non-feeding by the registration roller 14 as in the case where the above-described conveyance assist flag is 1. Then, the same conveyance assist process (S315, S316) is performed. In this case, the conveyance assist is performed from the beginning without detecting the document by the read sensor, so that the detection time is omitted compared with the case where the conveyance assist is performed after the non-feed is detected. It is possible to improve the performance.

  On the other hand, if the image duty (printing rate) is not equal to or greater than the predetermined value (NO in S312), it is determined that the document D is unlikely to cause non-feeding by the registration roller 14, and the discharge reversing roller 18 is separated by the solenoid SL. Only do. That is, the conveyance assist is not performed. The solenoid SL gradually performs suction by current control (S313). As described above, the generation of sound when the paper discharge reversing roller 18 is separated is suppressed.

  Next, it is determined whether or not the lead sensor (lead S) S3 has detected the leading edge of the document D during image reading on the second side (S314). If the leading edge of the document D cannot be detected within the first predetermined time after the re-rotation of the registration roller 14 (NO in S314), it is determined that the document D stays in the vicinity of the registration roller 14. Then, the paper discharge reversing roller 18 is brought into contact with the document D and pressed by the solenoid SL (S317). Then, the discharge reversing roller 18 is driven reversely for a predetermined time by the read motor M2 (S318) to assist the conveyance. As a result, the document D can be conveyed even when the registration roller 14 is not fed. Thereafter, the discharge reversing roller 18 is separated again by the solenoid SL (S319). Further, the conveyance assist flag on the RAM 51 is set to 1. As described above, when the non-feed occurs at least once, the flag is set. As a result, after the subsequent document D, the conveyance assist is performed from the beginning before the first predetermined time elapses. Therefore, compared with the case where the conveyance assist is performed after detecting the non-feed, Save time and improve productivity. Finally, the image reading unit 54 reads images on the second side (back side) of the document D (back side scan) (S321), and the document is reversed in an empty state (S322). Reading ends.

  As described above, according to the automatic document feeder 1 of the present embodiment, the conveyance assist by the paper discharge reversing roller 18 is not performed in a normal case where it is not necessary, but is performed only when necessary. As a result, in the normal case in which poor conveyance by the registration roller 14 is unlikely to occur, unnecessary motor driving for rotating the paper discharge reversing roller 18 can be avoided, and generation of sound at that time can be prevented. Further, by omitting the time for the conveyance assist, it is possible to devote the time to the time for separating the discharge reversing roller 18 at a low speed, and it is possible to improve the productivity while reducing the sound caused by the impact at the time of separation. There is an effect.

  D: Document, G: Flow-reading glass (image reading position), T1: Document placement tray (document placement portion), S3: Read sensor (document detection sensor), 1 ... Automatic document feeder, 12 ... Separation roller, DESCRIPTION OF SYMBOLS 14 ... Registration roller, 18 ... Discharge reverse roller (reverse roller), 50 ... Control part, 55 ... Image processing part (Print rate calculation means, Print rate determination means).

Claims (4)

An automatic document that transports the document set on the document placement section to the image reading position, and reverses the first image after scanning the image on the front and back to the image reading position for reading the second image. In the feeding device,
A registration roller that once stops the document conveyed from the document placement unit and then rotates and conveys the document toward the image reading position;
A document detection sensor disposed between the registration roller and the image reading position;
A reversing roller capable of contacting and separating, which conveys a document that has been turned upside down after image reading on the first side toward the registration roller;
A control unit that performs control of the registration roller and control of the reversing roller based on an output of the document detection sensor;
The controller is
When reading the image on the second side, if the document detection sensor does not detect a document within a first predetermined time after starting the separation of the reversing roller after the rotation of the registration roller is started, The conveyance assist is started by contacting the reverse roller,
An automatic document feeder characterized by that. The controller is
When the state in which the document detection sensor does not detect the document occurs at least once within the first predetermined time, the first roller after the rotation of the registration roller is started when reading the second image on the subsequent document. Before the predetermined time elapses,
The automatic document feeder according to claim 1. A separation roller capable of separating a document from a plurality of documents set on the document placement unit and stopping a document transport operation for transporting the document to the registration roller;
The controller is
When reading the image on the first side, if the document conveying operation of the separation roller is stopped after the rotation of the registration roller is started and the document detection sensor does not detect the document within a second predetermined time, the separation roller The document conveyance operation is started to assist the conveyance of the document, and at the time of reading the image on the second side of the document, the conveyance assist is performed before the first predetermined time elapses after the rotation of the registration roller is started. Start,
The automatic document feeder according to claim 1. The controller is
A printing rate calculating means for calculating a printing rate of an image read at the image reading position;
A printing rate determination unit that determines whether the printing rate calculated by the printing rate calculation unit is equal to or higher than a predetermined printing rate;
When the printing rate determining means determines that the printing rate of the first side of the document is equal to or higher than the predetermined printing rate, the image reading of the second side of the document is performed after the rotation of the registration roller is started. The conveyance assist is started before a predetermined time of 1 elapses;
The automatic document feeder according to claim 1.

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