JP2013112517A - Automatic paper feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suitably control start timing of paper feeding without directly using a dedicated sensor and without using a sensor on a conveyance path.SOLUTION: An automatic paper feeder includes a form tray part on which a bundle of forms to be fed is placed, a paper feed roll which moves down onto the bundle of forms placed on the form tray part to feed forms, and moves up after feeing the forms, a form length sensor which detects a length of the forms arranged on the form tray part, means of estimating a maximum form length from a detection state of the form length sensor, and means of starting paper feeding operation for a next form once it is determined on the basis of the estimated maximum form length that a form rear end has passed by the position of the paper feed roll.

Description

  The present invention relates to a technology for controlling an automatic sheet feeder in an image forming apparatus, an image reading apparatus, a sheet post-processing apparatus, and the like.

  In the automatic document feeder installed in the image reading device, when feeding of a document is started, a paper feed roller called a pickup roller is lowered to one end of the document loaded on the document tray to perform initial feeding. And the operation of raising the pickup roller when the document feeding is completed is repeated.

  By the way, in this type of automatic document feeder, for the purpose of improving productivity, the feeding of the next document (pre-feed) is performed before feeding one document and completing the image reading process. I'm trying to get started.

  However, when the pickup roller is lowered, the roller marks of the pickup roller may be stuck on the document or damage the document unless the trailing edge of the fed document passes through the pickup roller position. End up.

  For this reason, the pickup roller must be lowered after the trailing edge of the document has surely passed the pickup roller.

  In order to detect the timing at which the pickup roller is lowered, Japanese Patent Application Laid-Open No. 2004-228561 provides a sensor for detecting the trailing edge of the paper in the vicinity of the pickup roller.

  In Patent Document 2, the trailing edge of the document is detected using a sensor (abutment sensor) on the document conveyance path.

  In the method of providing the sensor for detecting the trailing edge of the paper near the pickup roller described above (upper part of the pickup roller), it is necessary to provide a dedicated sensor only for controlling the pickup roller, which increases the cost. There was a problem.

  In addition, in the method of detecting the trailing edge of the document using a sensor on the document conveyance path, the distance between the sensor on the conveyance path and the pickup roller is long, and prefeeding cannot be started immediately even when it is possible to feed paper. There was a problem that productivity would fall.

  The present invention has been proposed in view of the above-described conventional problems, and an object of the present invention is to appropriately control the start timing of paper feeding without directly using a dedicated sensor or a sensor on a conveyance path. There is.

  In order to solve the above problems, according to the present invention, a sheet tray unit on which a bundle of sheets to be fed is placed, and a sheet bundle placed on the sheet tray unit are lowered. The maximum paper length is estimated based on the detection state of the paper length sensor, the paper length sensor that detects the paper length disposed on the paper tray section, And means for starting a sheet feeding operation for the next sheet when it is determined that the trailing edge of the sheet has passed the position of the sheet feeding roller based on the estimated maximum sheet length.

  In the automatic paper feeder of the present invention, a dedicated sensor or a sensor on the conveyance path is directly used by estimating the paper length from the detection state of the paper length sensor that detects the paper length arranged on the paper tray. Without using it, it is possible to appropriately control the start timing of paper feed.

FIG. 3 is a diagram illustrating an example of the arrangement of an automatic document feeder and an image reading device. 2 is a diagram illustrating a configuration example of an automatic document feeder. FIG. 6 is a flowchart illustrating an example of overall processing of paper feed control during image reading. 6 is a flowchart illustrating a processing example of maximum document length determination. It is a flowchart which shows the example of a process of pre-feed operation start determination.

  Hereinafter, preferred embodiments of the present invention will be described. Although the case where the present invention is applied to an automatic document feeder will be described, it is needless to say that the present invention can also be applied to a case where a printed sheet is fed in a sheet post-processing apparatus.

<Configuration>
FIG. 1 is a diagram showing an example of the arrangement of an automatic document feeder 1 and an image reading device 2. The automatic document feeder 1 is arranged on the upper portion of the image reading device 2 and is exposed on the upper portion of the image reading device 2. The original (104) is conveyed to a contact glass (201) that serves as an image reading window.

  The image reading device 2 is provided with a control unit 21 that controls the image reading device 2 itself and the automatic document feeder 1.

  FIG. 2 is a diagram illustrating a configuration example of the automatic document feeder 1.

  There is a document tray 100 as a table on which documents 104 to be fed are stacked, and a document discharge tray 115 as a table on which documents 104 that have been read are stacked.

  There is a paper feed motor (not shown), and there are a pick-up roller 105, a separation roller 106, a pull-out roller 108, and a reverse path roller 117 as rollers and rollers connected to the paper feed motor.

  When the paper feed motor is reversed, the pickup roller 105, the separation roller 106, and the reverse path roller 117 are operated. The pull-out roller 108 does not rotate because of the one-way clutch.

  When the paper feed motor is rotated forward, the pickup roller 105, the separation roller 106, the pull-out roller 108, and the reverse path roller 117 are operated. However, the pickup roller 105 is provided with a clutch (not shown) and is not rotated during normal rotation because the clutch is disengaged.

  Further, a solenoid (not shown) is connected to the pickup roller 105. When the solenoid is operated, the pickup roller 105 is lowered. When the document 104 is set on the document tray 100, the pickup roller 105 is placed on the document 104. 105 is to ride.

  There is a conveyance motor (not shown), and there are a registration roller 110 and paper discharge rollers 112 and 114 as rollers connected to the conveyance motor.

  When the conveyance motor is rotated forward, the registration roller 110 and the paper discharge rollers 112 and 114 are operated.

  When the conveyance motor is reversed, the document setting claw 116 is raised, and when a solenoid (not shown) connected to the document setting claw 116 is operated, the document setting claw 116 is lowered.

  A solenoid (not shown) is connected to the reversing branch claw 118, and the conveyance path of the original 104 is switched by operating the solenoid.

  On the other hand, there are document length sensors 101 to 103 as sensors for detecting the length of the document 104, and the state of the document 104 is detected (ON when the document 104 exists on each sensor). ing. On the document conveyance path, there are an abutment sensor 107, a registration sensor 109, and a paper discharge sensor 113 as conveyance sensors, which detect whether or not the document 104 has reached the position of each sensor (the document 104 is at the position of each sensor). If it exists, it is turned ON).

  The position where the original 104 is read is a position of the contact glass 201 between the registration roller 110 and the paper discharge roller 112.

<Basic paper feeding operation>
In order to convey the original 104 loaded on the original tray 100 to the separation roller 106, the original setting claw 116 is lowered when it is not lowered, so that the original 104 can be conveyed to the conveyance path. The pickup roller 105 is also lowered and lowered onto the original 104. Therefore, the pickup roller 105 is rotated (reversed), and the document 104 is conveyed to the separation roller 106.

  The upper roller of the separation roller 106 is rotated in the conveyance direction, and the lower roller of the separation roller 106 is rotated in the direction opposite to the conveyance direction, thereby conveying the original 104 only on the top of the bundle of documents. By pushing back the document, the document 104 is prevented from entering the separation roller 106 in a bundle.

  The original 104 which has become only one sheet is further conveyed, passes through the abutting sensor 107, and reaches the pull-out roller 108. At this time, the pull-out roller 108 is not rotating, and the leading edge of the document is inserted into the pull-out roller 108 by a certain distance. The pickup roller 105 and the separation roller 106 are stopped at the time when they have penetrated a certain distance. By this operation, the leading edge of the document 104 becomes perpendicular to the conveyance direction, and thus the skew of the leading edge of the document 104 can be corrected.

  Next, the paper feed motor is rotated forward to rotate the pull-out roller 108 in the transport direction. Further, the conveyance motor is rotated forward to rotate the registration roller 110 and the paper discharge rollers 112 and 114 in the conveyance direction. Document 104 is conveyed and passes registration sensor 109, and registration roller 110 also passes. Thereafter, the sheet is conveyed for a certain distance, both motors are stopped in front of the contact glass 201, and the document 104 is stopped.

  Thereafter, when a reading operation instruction is received from the image reading device 2, the paper feed motor is rotated forward to rotate the pull-out roller 108 in the transport direction, and the transport motor is rotated forward to transport the registration rollers 110 and the paper discharge rollers 112 and 114. The original 104 is further conveyed by rotating in the direction.

  When the leading edge of the document 104 reaches the contact glass 201 which is the reading position, the automatic document feeder 1 transmits a reading start signal to the image reading device 2 and starts reading.

  When the rear end of the document 104 passes through the contact glass 201 which is a reading position, the automatic document feeder 1 transmits a reading end signal to the image reading device 2 and ends the reading.

  When only the surface of the original 104 is read, the reverse branching claw 118 does not operate (horizontal state), and the original 104 is discharged to the original discharge tray 115. Stop.

  When both the front surface and the back surface of the document 104 are read, the reversing branch claw 118 is lowered, the document 104 is conveyed to the reversing path roller 117, and the surface of the document 104 is reversed. When the trailing edge of the original 104 passes the reverse branch claw 118, both motors are stopped, the original 104 is stopped, the reverse branch claw 118 is raised, the paper feed motor is reversed, the transport motor is rotated forward, and the direction of the pull-out roller 108 is reached. The original 104 is conveyed to the front. After the original 104 reaches the pull-out roller 108, the same operation as the front surface is repeated. Then, the original 104 is reversed again, reaches the pull-out roller 108, and when the paper feed motor and the transport motor are operated, the original 104 is discharged to the original discharge tray 115, and when discharged, both motors are stopped to stop the operation. .

  However, even if only the front side or the front side or the back side is read, if the original 104 still remains on the original tray 100, the next original 104 from the original tray 100 before the original 104 is discharged to the original discharge tray 115. Is automatically fed (pre-feed). Pre-feeding is an operation that increases productivity by starting feeding of the next document before discharging of the previous document is finished.

<Overall process of paper feed control during image reading>
FIG. 3 is a flowchart showing an example of the overall processing of paper feed control during image reading.

  When processing is started in response to an instruction to start image reading from the user, it is determined by the document length sensors 101 to 103 whether or not a document is set on the document tray 100 (step S101), and any of the document length sensors 101 to 103 is determined. If it is determined that there is no document because no document is detected (Y in step S101), the process is terminated.

  If there is a document (N in step S101), the maximum document length is determined (step S102). The processing content of the maximum document length determination will be described later.

  Next, the first sheet feeding operation (starting from the lowering operation of the pickup roller 105) is started (step S103).

  Next, a pre-feed operation start determination is performed (step S104). The processing content of the pre-feed operation start determination will be described later.

  Next, it is determined whether or not a document is set by the document length sensors 101 to 103 (step S105), and it is determined that there is no document because none of the document length sensors 101 to 103 detects a document (step S105). Y), the process ends.

  If there is a document (N in step S105), the maximum document length is determined (step S106). The processing content of the maximum document length determination will be described later.

  Next, the pre-feed operation (starting from the lowering operation of the pickup roller 105) is started (step S107).

<Maximum document length judgment>
FIG. 4 is a flowchart showing a processing example of maximum document length determination (steps S102 and S106 in FIG. 3).

  Note that there is an operation mode for feeding paper, the normal mode that feeds the same original document in a standard format, the mixed size mode that feeds documents with the same document width and different document length, and the document length in advance. There is a long document mode for specifying and reading.

  First, it is determined whether or not it is the first document feed (step S201). If it is the first (Y in step S201), the document length is estimated.

  In the case of the second and subsequent sheets (N in step S201), it is determined whether or not the mode is the mixed loading mode (step S206), and in the mixed loading mode (Y in step S206), the document length is estimated.

  When the mixed mode is not set (N in step S206), the document length determined by conveying the first document is set as the maximum document length (step S211). The document length determined by transporting the first document can be calculated from the time required to pass a predetermined sensor in the transport path and the transport speed.

  When the document length is to be estimated (Y in step S201, Y in step S206), first, the detection state of the first document length sensor 101 that detects the longest document length is confirmed (step S202). If it is detected (Y in step S202), it is determined whether or not it is in the long document mode (step S207). In the long document mode (Y in step S207), the automatic document feeder 1 can pass the sheet. The maximum document length, for example 1260 mm, is set as the estimated document length (step S213).

  When the long document mode is not set (N in step S207), the estimated document length is set to, for example, 432 mm, which is the maximum document length that can be passed in a standard size (step S212).

  Next, when the document length sensor 101 is not detected (N in Step S202), the detection state of the second document length sensor 102 is confirmed (Step S203), and when it is detected (Y in Step S203). For example, 320 mm, which is the maximum document length that is not detected by the first document length sensor 101, is set as the estimated document length (step S210).

  If the document length sensor 102 is not detected (N in step S203), the detection state of the third document length sensor 103 is confirmed (step S204), and if it is detected (Y in step S204), 2 is detected. For example, 291 mm, which is the maximum document length not detected by the second document length sensor 102, is set as the estimated document length (step S209).

  If the document length sensor 103 is not detected (N in step S204), the maximum document length, for example, 242 mm, which is the maximum document length not detected by the third document length sensor 103, is set as the maximum document length (step S205).

<Pre-feed operation start determination>
FIG. 5 is a flowchart showing a processing example of the pre-feed operation start determination (step S104 in FIG. 3).

  First, it is determined whether or not the trailing edge of the document having the estimated document length obtained in the maximum document length determination (FIG. 4) has passed the pickup roller 105 (step S301). This determination can be made by measuring the time obtained by dividing the estimated document length by the conveyance speed from the start of paper feeding.

  If it is determined that the trailing edge of the document having the estimated document length has passed the pickup roller 105 (Y in step S301), the process is terminated, and feeding of the next document is started by the pre-feed operation.

  If it is determined that the trailing edge of the document with the estimated document length has not passed through the pickup roller 105 (N in step S301), it is subsequently determined whether or not the trailing edge of the document has been detected in the conveyance path by the abutment sensor 107 ( Step S302).

  If it is determined that the trailing edge of the document is not detected by the abutting sensor 107 (N in step S302), the process returns to the determination (step S301) of whether the trailing edge of the document having the estimated document length has passed the pickup roller 105.

  If it is determined that the trailing edge of the document has been detected by the abutting sensor 107 (Y in step S302), the process is terminated, and feeding of the next document is started by a pre-feed operation.

  The above operation is based on the following considerations. That is, when feeding paper, the pickup roller 105 is lowered and the motor is rotated, but the pickup roller 105 is placed on the original 104 only after the previously fed original 104 passes through the pickup roller 105. Therefore, the document is conveyed in the direction in which the document 104 is pulled, and the document 104 may have a roller mark or be damaged. In addition, after the trailing edge of the document has passed through the abutting sensor 107, the trailing edge of the document 104 has sufficiently passed through the pickup roller 105, so that productivity decreases.

  Therefore, in order to detect that the abutting sensor 107 has passed through the pickup roller 105 as soon as possible before the trailing edge of the document 104 is detected, an estimated maximum document length is obtained. By starting paper feeding when the roller 105 passes, the next document feeding operation can be accelerated, productivity can be improved, and the adverse effect of the pickup roller 105 on the document 104 can be prevented.

  By repeating the above operations, a large amount of originals can be continuously fed with high productivity.

<Summary>
As described above, the present embodiment has the following advantages.

  (1) A sensor for detecting a document length on a document tray is used to estimate the document length, to estimate the timing at which the trailing edge of the document leaves the pickup roller, and to start feeding at that timing. Therefore, it is possible to appropriately control the sheet feeding operation timing, and it is possible to prevent the document from being stained and damaged while increasing the productivity.

  (2) When the sensor on the document transport path detects that the trailing edge of the document has passed a certain position, the feeding operation for the next document is started, so that productivity can be improved even when the estimated document length is not appropriate. Paper can be fed without significantly reducing the.

  (3) If the mode is not a mode for feeding originals of different sizes, for the second and subsequent sheets, the estimated original length is set to the original length determined by conveying the first original, so that The timing for removing the pickup roller can be determined based on the correct document length for the document, and the sheet feeding operation timing can be advanced to the first or more sheets.

  (4) When documents of different lengths are on the document tray, the estimated document length may be shortened when the longest document is fed. By estimating the maximum document length for each sheet, Thereafter, the paper feed operation timing can be advanced.

  (5) In the mode of feeding an irregular document, if the document length sensor that detects the longest document length has detected, the estimated document length is set to the maximum document length that the automatic sheet feeder can pass. Therefore, it can be suppressed within the capability of the apparatus.

  (6) If the document length sensor that detects the longest document length is detected when the mode is not a mode for feeding an irregular document, the automatic document feeder can pass the estimated document length within the standard size. By setting the maximum document length, the operation timing of paper feeding can be made earlier than the maximum document that can be fed by a non-standard size apparatus.

  The present invention has been described above by the preferred embodiments of the present invention. While the invention has been described with reference to specific embodiments, various modifications and changes may be made to the embodiments without departing from the broad spirit and scope of the invention as defined in the claims. Obviously you can. In other words, the present invention should not be construed as being limited by the details of the specific examples and the accompanying drawings.

DESCRIPTION OF SYMBOLS 1 Automatic document feeder 100 Document tray 101-103 Document length sensor 104 Document 105 Pick-up roller 106 Separation roller 107 Abutment sensor 108 Pull-out roller 109 Registration sensor 110 Registration roller 112 Paper discharge roller 113 Paper discharge sensor 114 Paper discharge roller 115 Document Discharge tray 116 Document setting claw 117 Reverse path roller 118 Reverse branch claw 2 Image reading device 21 Control unit 201 Contact glass

JP 2011-24098 A JP 2011-84399 A

Claims (6)

A paper tray on which a bundle of paper to be fed is placed;
A paper feeding roller that descends onto a bundle of papers placed on the paper tray unit and feeds papers, and rises after paper feeding;
A paper length sensor for detecting a paper length disposed on the paper tray portion;
Means for estimating a maximum sheet length from a detection state of the sheet length sensor;
And an automatic paper feeding unit that starts a paper feeding operation for the next paper when it is determined that the trailing edge of the paper has passed the position of the paper feeding roller based on the estimated maximum paper length. apparatus. The automatic paper feeder according to claim 1.
The means for starting the paper feeding operation is not limited to the time when it is determined that the paper trailing edge has passed the position of the paper feeding roller based on the estimated maximum paper length, and the paper trailing edge is fixed by a sensor on the paper conveyance path. An automatic paper feeding device which starts a paper feeding operation for the next paper when it is detected that the position has been passed. In the automatic paper feeder according to claim 1 or 2,
An automatic paper feeding device characterized in that, when the mode is not a mode for feeding paper sheets of different sizes, the estimated paper length for the second and subsequent sheets is set to a paper length determined by conveying the first paper sheet. In the automatic paper feeder according to claim 1 or 2,
An automatic paper feeder that estimates a maximum paper length for each sheet in a mode in which paper of different sizes is fed. In the automatic paper feeder according to claim 1 or 2,
In the mode that feeds non-standard paper, if the paper length sensor that detects the longest paper length has been detected, the estimated paper length is set to the maximum paper length that the automatic paper feeder can pass. Automatic paper feeder. In the automatic paper feeder according to claim 1 or 2,
If the paper length sensor that detects the longest paper length is detected when the mode is not for feeding irregular-size paper, the estimated paper length is the maximum paper length that the automatic paper feeder can pass within the standard size. An automatic paper feeder characterized by the above.

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