JP2012236684A - Sheet feeding device, and method and program for controlling the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet feeding device capable of efficiently feeding sheets, and a method and a program for controlling the sheet feeding device.SOLUTION: A sheet feeding part 10 as the sheet feeding device includes a pickup roller 101 for picking up the sheets SH, a sheet feeding roller 102 for feeding the sheets SH which are picked up by the pickup roller 101 while separating them from one another one by one, and a loosening roller 103. The sheet feeding part 10 includes a sheet feeding sensor unit 151 which detects the presence or absence of a gap between the sheet SH carried in a feeding section and the next sheet SH at least at two points in the feeding section from a position of the pickup roller 101 to a position on a downstream side with respect to a nip between the sheet feeding roller 102 and the loosening roller 103, and a brushless DC brushless motor which synchronously drives the pickup roller 101, the sheet feeding roller 102 and the loosening roller 103 on the basis of the presence or absence of the gap detected by the sheet feeding sensor unit 151.

Description

  The present invention relates to a sheet conveying apparatus, a method for controlling the sheet conveying apparatus, and a control program for the sheet conveying apparatus. More specifically, the present invention relates to a sheet conveying apparatus for conveying sheets in an image forming apparatus, a method for controlling a sheet conveying apparatus, And a control program for the sheet conveying apparatus.

  Electrophotographic image forming apparatuses include a scanner function, a facsimile function, a copying function, a function as a printer, a data communication function, and a server function, an MFP (Multi Function Peripheral), a facsimile apparatus, a copying machine, a printer, and the like. is there.

  The image forming apparatus mainly includes an image forming unit and a paper transport unit. The image forming unit forms a toner image on the image carrier, and forms an image on the sheet by transferring the toner image to the sheet and pressing it. The paper transport unit takes out the paper one by one from the paper feed tray, and feeds the paper to the image forming unit at a timing by a timing roller. The paper transport unit transports the paper to the paper discharge tray after image formation.

  The conventional paper transport unit detects a gap between papers using a sensor in order to correct the distance between the trailing edge of the preceding paper and the leading edge of the succeeding paper when the paper is continuously conveyed. Such a technique is disclosed, for example, in Patent Documents 1 and 2 below.

  In Patent Document 1 below, a feeding unit that feeds a sheet material from a sheet material storage unit, a separation conveyance unit that separates the sheet material fed by the feeding unit one by one, and the vicinity of the separation conveyance unit A sheet feeding device provided with a detecting means provided in the sheet material passage region is disclosed. In this paper feeding device, the feeding means is controlled independently of the separating and conveying means, and the timing for feeding the next sheet material by the feeding means from the sheet material storing means is appropriately changed based on the detection of the sheet material by the detecting means. The feeding means is controlled to do so.

  In the following Patent Document 2, a transfer material feeding unit that separates and feeds a transfer material, a first resist unit that corrects the tip position of the transfer material fed by the transfer material feeding unit, and a first resist unit, An image forming apparatus having a second resist unit that is positioned between the transfer position by the transfer unit and corrects the leading end position of the transfer material is disclosed.

Japanese Patent Laid-Open No. 2003-165639 JP 2000-143040 A

  As the speed of image forming apparatuses increases, when an image is formed by continuously conveying a plurality of sheets, it is desired to reduce the interval between sheets to be conveyed and to convey the sheets efficiently. However, the conventional technology has poor paper conveyance efficiency.

  In Patent Document 1, if the detection unit does not detect that the trailing edge of the sheet has passed through the sheet material passage region, the feeding unit does not feed the next sheet. For this reason, the interval between the sheets becomes large, and the conveyance efficiency of the sheets sometimes deteriorates. Further, since it is necessary to drive the feeding means and the separating and conveying means independently, the size of the apparatus is increased.

  In Patent Document 2, since the distance between the transfer materials is corrected by the conveyance unit that conveys the sheet, there are means for determining the distance between the sheets, first and second registration means for correcting the sheet based on the determination result, and the like. There is a problem that the number of components of the device increases and the size of the device increases. In addition, when the paper is transported from a one-stage paper cassette, the accuracy of adjusting the paper interval may be deteriorated.

  SUMMARY An advantage of some aspects of the invention is that it provides a sheet conveying apparatus capable of efficiently conveying a sheet, a method for controlling the sheet conveying apparatus, and a control program for the sheet conveying apparatus. It is to be.

  Another object of the present invention is to provide a sheet conveying apparatus, a method for controlling the sheet conveying apparatus, and a control program for the sheet conveying apparatus that can reduce the size of the apparatus.

  A sheet conveying apparatus according to one aspect of the present invention is a sheet conveying apparatus including a pickup unit that picks up a sheet and a feeding unit that separates and feeds the sheets picked up by the pickup unit one by one, Detecting means for detecting presence / absence of a gap between the sheet conveyed in the conveying section and the next sheet at at least two points in the conveying section from the position of the pickup means to a position downstream of the feeding means; Driving means for driving the pickup means and the feeding means in synchronism based on the presence or absence of the detected gap.

  Preferably, in the above-described paper transport device, the detection unit detects the presence or absence of a gap in the entire transport section.

  Preferably, the sheet conveying apparatus further includes a conveying unit that conveys the sheet at a position downstream of the feeding unit and closest to the feeding unit, and the detection unit conveys the sheet to the position of the conveying unit. Detect the presence or absence of gaps in the section.

  Preferably, the sheet conveying apparatus further includes a position specifying unit that specifies a position where the gap is generated based on a timing at which the detection unit detects the gap, and the driving unit is based on the position specified by the position specifying unit. The pickup means and the feeding means are driven.

  Preferably, the sheet conveying apparatus further includes a sheet detecting unit that detects a sheet conveyed by the conveying unit, and a speed at which the sheet is fed by the feeding unit is larger than a speed at which the sheet is conveyed by the conveying unit. In this case, the position specifying means includes the time from the time when the leading edge of the paper is detected by the paper detecting means to the time when the gap is detected by the detecting means, the speed at which the paper is conveyed by the conveying means, and the paper along the conveying direction. Based on the length of the position, the position where the interval is generated is specified, and the driving means drives the pickup means and the feeding means from the time when the detecting means detects the gap based on the position specified by the position specifying means. Time setting means for setting a waiting time until the time is included.

  Preferably, in the paper transporting apparatus, the detection unit includes a light emitting unit that emits light and a light receiving unit that receives light from the light emitting unit, and the gap is determined based on whether the light from the light emitting unit is received by the light receiving unit. Detect the presence or absence.

  Preferably, in the above-mentioned paper transport device, the detection means further includes a diffusing means for diffusing the light of the light emitting means so that light is irradiated to the paper transported in the transport section.

  Preferably, in the above-described paper transport device, the detection unit further includes a light collecting unit that collects light from the light emitting unit onto the light receiving unit.

  Preferably, in the paper transport apparatus, the detection unit further includes a reflection unit that reflects the light of the light emitting unit and irradiates the paper transported in the transport section.

  Preferably, in the paper transporting device, the light emitting means is provided on one side of the paper transport path, the light receiving means is provided on the other side of the paper transport path, and the light receiving means transmits the light transmitted through the gap between the paper and the next paper. Receive light.

  Preferably, in the paper conveying apparatus, the light receiving unit is a line sensor, and the detection unit detects the gap when the output of the line sensor is high in a certain section.

  Preferably, in the paper transporting apparatus, the light receiving means includes a plurality of light receiving means, and the detecting means determines the intensity of light transmitted through the gap between the paper and the next paper when the trailing edge of the paper is separated from the leading edge of the next paper. Further comprising intensity acquisition means acquired from a plurality of light receiving means and combining means for combining the intensity acquired by the intensity acquiring means into a 1-bit signal, the driving means based on the 1-bit signal combined by the combining means The pickup means and the feeding means are driven.

  Preferably, in the paper transport device, both the light emitting means and the light receiving means are provided on one side of the paper transport path.

  Preferably, in the paper conveying apparatus, the light receiving unit is a line sensor, and the detection unit detects the gap when the output of the line sensor is low in a certain section.

  According to another aspect of the present invention, there is provided a control method for a paper transport device, comprising: a pick-up device that picks up paper; and a paper feed device that separates and feeds the paper picked up by the pick-up device one by one. A detection method for detecting presence or absence of a gap between a sheet conveyed in the conveyance section and the next sheet at at least two points in the conveyance section from the position of the pickup unit to a position downstream of the feeding unit. And a driving step for driving the pickup means and the feeding means in synchronization based on the presence or absence of a gap detected in the detection step.

  According to another aspect of the present invention, there is provided a control program for a paper transport device, comprising: a pick-up unit that picks up paper; and a paper feed unit that separates and feeds the paper picked up by the pick-up unit one by one. A detection program for detecting the presence or absence of a gap between a sheet conveyed in the conveyance section and the next sheet at at least two points in the conveyance section from the position of the pickup means to a position downstream of the feeding means. Based on the presence or absence of the gap detected in the detection step, the computer is caused to execute a driving step for driving the pickup means and the feeding means in synchronization.

  According to the present invention, it is possible to provide a sheet conveying apparatus, a method for controlling the sheet conveying apparatus, and a control program for the sheet conveying apparatus that can efficiently convey the sheet and reduce the size of the apparatus.

FIG. 2 is a cross-sectional view schematically showing a partial configuration of MFP 1 in the first embodiment of the present invention. FIG. 2 is a block diagram showing a configuration of MFP 1 in FIG. 1. 3 is a diagram illustrating a configuration of a transport path R in the vicinity of a paper feed sensor unit 151 when viewed from the horizontal direction of the transport path R in the first embodiment of the present invention. FIG. FIG. 3 is a diagram illustrating a configuration of a transport path R in the vicinity of a paper feed sensor unit 151 when viewed from the downstream side of the transport path R in the first embodiment of the present invention. FIG. 5 is a diagram illustrating a configuration of a transport path R in the vicinity of a paper feed sensor unit 151 when viewed from a direction perpendicular to a paper surface of a sheet transported along the transport path R in the first embodiment of the present invention. . FIG. 6 is a first diagram illustrating an operation of the sheet conveying unit when continuously conveying a preceding sheet and a succeeding sheet in the first embodiment of the present invention. FIG. 10 is a second diagram illustrating the operation of the sheet conveying unit when conveying the preceding sheet and the succeeding sheet continuously in the first embodiment of the present invention. FIG. 10 is a third diagram illustrating an operation of the sheet transport unit 10 when the preceding sheet and the succeeding sheet are continuously transported in the first embodiment of the present invention. FIG. 10 is a fourth diagram illustrating the operation of the sheet transport unit 10 when the preceding sheet and the succeeding sheet are transported continuously in the first embodiment of the present invention. FIG. 10 is a fifth diagram illustrating an operation of the sheet transport unit 10 when the preceding sheet and the succeeding sheet are continuously transported in the first embodiment of the present invention. FIG. 10 is a sixth diagram illustrating the operation of the sheet conveying unit when conveying the preceding sheet and the succeeding sheet continuously in the first embodiment of the present invention. FIG. 10 is a seventh diagram illustrating the operation of the sheet conveying unit when the preceding sheet and the succeeding sheet are continuously conveyed in the first embodiment of the present invention. It is a time chart which shows the operation state of each member when the succeeding paper is carried along with the preceding paper when the preceding paper is fed. 4 is a flowchart illustrating a paper feed control process executed by the paper transport unit 10. FIG. 10 is a diagram illustrating a configuration of a transport path R in the vicinity of a paper feed sensor unit 151 when viewed from the horizontal direction of the transport path R in the second embodiment of the present invention. FIG. 10 is a diagram illustrating a configuration of a transport path R in the vicinity of a paper feed sensor unit 151 when viewed from the downstream side of the transport path R in the second embodiment of the present invention. FIG. 10 is a first diagram illustrating an operation of the sheet conveying unit when conveying a preceding sheet and a succeeding sheet continuously in the second embodiment of the present invention. FIG. 10 is a second diagram illustrating the operation of the sheet conveying unit when the preceding sheet and the succeeding sheet are continuously conveyed in the second embodiment of the present invention. FIG. 10 is a third diagram illustrating the operation of the sheet transport unit 10 when the preceding sheet and the succeeding sheet are continuously transported in the second embodiment of the present invention. FIG. 10 is a fourth diagram illustrating the operation of the sheet transport unit 10 when the preceding sheet and the succeeding sheet are continuously transported in the second embodiment of the present invention. FIG. 10 is a fifth diagram illustrating an operation of the sheet transport unit 10 when transporting a preceding sheet and a succeeding sheet continuously in the second embodiment of the present invention. 10 is a table showing a method of combining the intensity of light received by paper feed sensors 164a and 164b into a 1-bit signal in the second embodiment of the present invention. It is a time chart which shows the operation state of each member when the succeeding paper is carried along with the preceding paper when the preceding paper is fed. FIG. 10 is a diagram illustrating a configuration of a transport path R in the vicinity of a paper feed sensor unit 151 when viewed from the horizontal direction of the transport path R in the third embodiment of the present invention. FIG. 10 is a diagram illustrating a configuration of a transport path R in the vicinity of a paper feed sensor unit 151 when viewed from the upstream side of the transport path R in the third embodiment of the present invention. FIG. 10 is a first diagram illustrating an operation of the sheet transport unit when a succeeding sheet SH2 is fed to the preceding sheet SH1 when the preceding sheet SH1 is fed in the fourth embodiment of the present invention. . FIG. 16 is a second diagram illustrating the operation of the sheet transport unit 10 when the succeeding sheet SH2 is fed to the preceding sheet SH1 when the preceding sheet SH1 is fed in the fourth embodiment of the present invention. . It is a table | surface which shows the relationship between the position where the carry-over was canceled, and the calculated waiting time. It is a time chart which shows the operation state of each member when succeeding paper SH2 is carried along with preceding paper SH1 when preceding paper SH1 is fed. 30 is a table showing an example of the relationship between the time and the position of the trailing edge of the preceding sheet SH1 in the case of FIG. 4 is a flowchart illustrating a paper feed control process executed by the paper transport unit 10. FIG. 10 is a diagram illustrating a configuration of a transport path R in the vicinity of a paper feed sensor unit 151 when viewed from the horizontal direction of the transport path R in a fourth embodiment of the present invention. FIG. 10 is a diagram illustrating a configuration of a transport path R in the vicinity of a paper feed sensor unit 151 when viewed from the downstream side of the transport path R in the fourth embodiment of the present invention. 10 is a table showing a method of combining the intensity of light received by the paper feed sensor 164 into a 1-bit signal in the fourth embodiment of the present invention. FIG. 10 is a diagram illustrating a configuration of a transport path R in the vicinity of a paper feed sensor unit 151 when viewed from the horizontal direction of the transport path R in a fifth embodiment of the present invention. FIG. 10 is a diagram illustrating a configuration of a transport path R in the vicinity of a paper feed sensor unit 151 when viewed from the downstream side of the transport path R in the fifth embodiment of the present invention. 20 is a table showing a method of combining the intensity of light received by the paper feed sensor 164 into a 1-bit signal in the fifth embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  In the following embodiments, a sheet conveying apparatus that conveys a sheet in an image forming apparatus will be described as an example of a sheet conveying apparatus. The image forming apparatus forms an image by, for example, an electrophotographic system or an electrostatic recording system, and is an MFP having a scanner function, a facsimile function, a copying function, a function as a printer, a data communication function, and a server function. It may be a facsimile machine, a copier, a printer, or the like.

[First Embodiment]
FIG. 1 is a cross-sectional view schematically showing a partial configuration of MFP 1 in the first embodiment of the present invention.

  Referring to FIG. 1, MFP 1 as an image forming apparatus in the present embodiment mainly includes a paper transport unit 10 (an example of a paper transport device), a toner image forming unit 20, and a fixing unit 30. . The paper SH loaded in the paper feeding device 40 (paper feeding cassette) disposed below the MFP 1 is transported along the transport path R by the paper transport unit 10 one by one during image formation. The sheet fed from the sheet feeding device 40 to the transport path R is transported to the toner image forming unit 20. The toner image forming unit 20 includes an intermediate transfer belt 230, a secondary transfer roller 240, and the like. The toner image forming unit 20 transfers the toner image formed on the intermediate transfer belt 230 by an imaging unit (not shown) onto the paper SH by the secondary transfer roller 240. The sheet SH on which the toner image is transferred is then conveyed to the fixing unit 30. The fixing unit 30 includes a heating roller 310 and a pressure roller 320. The fixing unit 30 conveys the paper SH on which the toner image is transferred while being sandwiched between the heating roller 310 and the pressure roller 320, and performs heating and pressure therebetween. As a result, the fixing unit 30 melts the toner adhering to the paper SH to heat and fixes the toner on the paper SH. The paper SH on which the toner image is fixed by the fixing unit 30 is then discharged to the paper discharge tray 41.

  The paper transport unit 10 includes a pickup roller 101, a paper feed roller 102 and a separating roller 103 (an example of a feeding unit), a vertical transport roller 104 (an example of a transport unit), a timing roller 105, and a paper discharge roller 106. Is included. These rollers are arranged in this order from the paper feeding device 40 side (hereinafter sometimes referred to as the upstream side) toward the paper discharge tray 41 side (hereinafter sometimes referred to as the downstream side) along the transport path R. Is arranged in.

  The paper transport unit 10 further includes a paper feed sensor unit 151, a vertical transport sensor 152, a timing sensor 153, a loop sensor 154, and a paper discharge sensor 155. The paper feed sensor unit 151 is transported in this transport section in the transport section from the position of the pickup roller 101 to the position of the vertical transport roller 104 (hereinafter, this section may be referred to as transport section A (FIG. 3)). The presence / absence of a gap between the next sheet (leading sheet) and the next sheet (following sheet) is detected. The MFP 1 drives the pickup roller 101, the paper feed roller 102, and the separating roller 103 synchronously based on the presence or absence of a gap detected by the paper feed sensor unit 151. The vertical conveyance sensor 152 is provided on the downstream side of the vertical conveyance roller 104. The timing sensor 153 is provided on the upstream side of the timing roller 105. The loop sensor 154 is provided between the secondary transfer roller 240 and the fixing unit 30 and detects the loop amount of the paper SH. The paper discharge sensor 155 is provided between the fixing unit 30 and the paper discharge roller 106. The vertical conveyance sensor 152, the timing sensor 153, and the paper discharge sensor 155 detect the paper SH being conveyed at each position.

  Next, an outline of the operation of the paper transport unit 10 will be described.

  When the MFP 1 accepts a job that uses the paper SH such as a print job or a copy job, the paper SH stored in the paper feeding device 40 is picked up one by one by the pickup roller 101, and the paper feeding roller 102 and the paper roller 103 are picked up. It is conveyed through the nip part. At this time, a succeeding sheet may be carried along with the preceding sheet (multiplely fed) to reach the sheet feeding roller 102. In this case, the preceding paper and the following paper are separated and fed one by one by the nip portion between the paper feed roller 102 and the separating roller 103. The paper feed sensor unit 151 detects whether or not the feed state has been canceled by the paper feed roller 102 and the separation roller 103, and if it detects that the carry state has not been released, the MFP 1 has jammed. Judge. The sheet conveyed through the nip portion between the sheet feeding roller 102 and the separating roller 103 is conveyed to the vertical conveying roller 104 using the sheet feeding roller 102 as a driving source. The pickup roller 101, the paper feed roller 102, and the separation roller 103 are driven in synchronism and convey a sheet of paper to the vertical conveyance roller 104 (or after a predetermined time has elapsed since the vertical conveyance sensor 152 detects the paper). Stop.

  The sheet conveyed to the vertical conveyance roller 104 is conveyed to the timing roller 105 by the vertical conveyance roller 104. When the paper passes through the vertical conveyance roller 104, the vertical conveyance sensor 152 detects the leading edge of the paper.

  Here, the paper conveyance speed is set to be faster for the pickup roller 101, the paper feed roller 102, and the separating roller 103 than for the vertical conveyance roller 104. For this reason, when the paper transport unit 10 continuously transports the paper, the paper transport unit 10 transports the succeeding paper after the pickup roller 101, the paper feed roller 102, and the separating roller 103 transport the preceding paper. By adjusting the time until the start, it is possible to control the gap between the preceding sheet and the succeeding sheet (paper interval). This control is performed based on the detection results of the paper feed sensor unit 151 and the vertical conveyance sensor 152.

  The timing sensor 153 is used when aligning the leading end of the sheet with the timing roller 105. At the time of image output, the sheet is conveyed from the timing roller 105 to the secondary transfer roller 240, and the toner image on the intermediate transfer belt 230 is transferred to the secondary transfer roller as the sheet passes through the secondary transfer roller 240. It is conveyed to 240. Then, the toner image is transferred from the intermediate transfer belt 230 to the sheet by the secondary transfer roller 240. When transporting the sheet onto which the toner image has been transferred to the fixing unit 30, the sheet transport unit 10 loops a certain amount of the paper so that the sheet SH is not pulled between the secondary transfer roller 240 and the fixing unit 30. The sheet SH is conveyed while forming the sheet. At this time, the loop sensor 154 detects the loop amount of the paper. The paper SH that has passed through the fixing unit 30 is discharged from the paper discharge roller 106 to the outside of the apparatus. At this time, the paper discharge sensor 155 detects the overlap of the sheets SH in order to prevent the sheets SH from being overlapped and discharged.

  The distance from the nip portion of the pickup roller 101 to the nip portion between the paper feed roller 102 and the separating roller 103 is, for example, 50 mm, and the nip of the vertical conveying roller 104 from the nip portion between the paper feeding roller 102 and the separating roller 103 is, for example, The distance to the part is 80 mm, for example. The rotational speed of the pickup roller 101, the rotational speed of the paper feed roller 102, and the rotational speed of the separating roller 103 are equal to each other, for example, 100 mm / s.

  FIG. 2 is a block diagram showing a configuration of MFP 1 in FIG.

  Referring to FIG. 2, MFP 1 further includes DC brushless motors (BLM) 171 a to 171 c, a control unit 51, and a storage unit 52.

  The control unit 51 controls the entire MFP 1 for various jobs such as a scan job, a copy job, a mail transmission job, and a print job. The control unit 51 executes the control program stored in the storage unit 52. The control unit 51 reads data from the storage unit 52 and writes data to the storage unit 52 by performing predetermined processing. The control unit 51 performs activation control of each of the DC brushless motors 171a to 171c based on detection results of the paper feed sensor unit 151, the vertical conveyance sensor 152, the timing sensor 153, the loop sensor 154, and the paper discharge sensor 155. .

  The storage unit 52 is used for storing data necessary when the control unit 51 executes a control program.

  Each of DC brushless motors 171 a to 171 c drives each roller in MFP 1.

  FIG. 3 is a diagram illustrating a configuration of the transport path R in the vicinity of the paper feed sensor unit 151 when viewed from the horizontal direction of the transport path R in the first embodiment of the present invention. FIG. 4 is a diagram illustrating the configuration of the transport path R in the vicinity of the paper feed sensor unit 151 when viewed from the downstream side of the transport path R in the first embodiment of the present invention.

  Referring to FIGS. 3 and 4, the drive source of pickup roller 101, paper feed roller 102, and separating roller 103 is the same DC brushless motor 171a. The DC brushless motor 171a drives the pickup roller 101, the paper feed roller 102, and the separating roller 103 in synchronization. The vertical conveying roller 104 is driven by a DC brushless motor 171b different from the DC brushless motor 171a. The driving source of the timing roller 105 is still another DC brushless motor 171c.

  The paper feed sensor unit 151 includes a lamp 161 (an example of a light emission unit), a diffusion plate 162 (an example of a diffusion unit), a light collector 163 (an example of a light collection unit), and a paper feed sensor 164 (an example of a light reception unit). Including. The lamp 161 is provided on the upper side in FIG. 3 of the transport path R and emits light (is a light source). The diffusion plate 162 is provided between the ramp 161 on the upper side of the transport path R in FIG. 3 and the transport path R, and is in the vertical direction of the paper SH transported in the transport section A (on the paper surface of the paper). (As opposed to) diffusing and irradiating light. The light collector 163 is provided on the opposite side of the lamp 161 (lower side in FIG. 3) across the transport path R. The light collector 163 collects light from the lamp 161 that has passed through the gap between the trailing edge of the preceding paper and the leading edge of the succeeding paper when the trailing edge of the preceding paper is separated from the leading edge of the following paper. The paper feed sensor 164 is provided between the light collector 163 and the transport path R on the lower side of the transport path R in FIG. 3, and receives light collected by the light collector 163. The paper feed sensor 164 can detect the presence or absence of a gap in the entire transport section A by the action of the diffusion plate 162 and the light collector 163.

  FIG. 5 shows the configuration of the transport path R in the vicinity of the paper feed sensor unit 151 when viewed from the direction perpendicular to the paper surface of the paper transported along the transport path R in the first embodiment of the present invention. FIG. (A) is the figure seen from the upper side in FIG. 3, (b) is the figure seen from the lower side in FIG.

  Referring to FIG. 5, paper feed sensor unit 151 detects the presence or absence of a gap between sheets based on whether or not light from lamp 161 is received by paper feed sensor 164. Specifically, while the succeeding sheet SH2 is being carried along with the preceding sheet SH1, the light from the lamp 161 is blocked by the preceding sheet SH1 and the succeeding sheet SH2, and the paper feed sensor 164 is light from the lamp 161. Not receive. On the other hand, when the trailing edge of the preceding sheet SH1 is separated from the leading edge of the succeeding sheet SH2, the paper feed sensor 164 receives light from the lamp 161 inserted through the gap between the trailing edge of the preceding sheet SH1 and the leading edge of the succeeding sheet SH2.

  Next, the operation of the sheet conveying unit 10 when conveying the preceding sheet and the succeeding sheet continuously will be described with reference to FIGS. In FIGS. 6 to 12, an arrow is attached to the driving roller, and an arrow is not attached to the stopped roller.

  Referring to FIG. 6, first, the paper transport unit 10 drives a pickup roller 101, a paper feed roller 102, a separating roller 103, and a vertical transport roller 104. As a result, the preceding sheet SH1 is fed from the sheet SH stored in the sheet feeding device 40 (FIG. 1), and the preceding sheet SH1 is conveyed along the conveying path R. The preceding sheet SH1 is conveyed using the pickup roller 101, the paper feed roller 102, and the separating roller 103 as a drive source on the upstream side of the vertical conveyance roller 104, and the vertical conveyance roller 104 is a drive source on the downstream side of the vertical conveyance roller 104. As conveyed.

  In the state where the sheet is not transported in the transport section A, the light of the lamp 161 is received by the paper feed sensor 164 as shown by an arrow L1 in FIG. On the other hand, the light from the lamp 161 is not received by the paper feed sensor 164 until the trailing edge of the preceding paper SH1 leaves the pickup roller 101 after the preceding paper SH1 is fed. This is because the preceding sheet SH1 exists over the entire conveyance section A, and the preceding sheet SH1 blocks the light of the lamp 161.

  With reference to FIG. 7, when the vertical conveyance sensor 152 detects the leading edge of the preceding paper SH <b> 1, the paper conveyance unit 10 stops driving the pickup roller 101, the paper feed roller 102, and the separation roller 103. The preceding sheet SH1 is then transported using the vertical transport roller 104 as a drive source.

  Referring to FIG. 8, when the succeeding sheet SH2 is not carried along with the preceding sheet SH1 when the preceding sheet SH1 is fed, at the moment when the trailing edge of the preceding sheet SH1 leaves the pickup roller 101, the lamp 161 is turned on. The light is received by the paper feed sensor 164 through the gap between the trailing edge of the preceding sheet SH1 and the leading edge of the succeeding sheet SH2. This light is indicated by an arrow L2 in FIG. As a result, the paper feed sensor unit 151 detects a gap between the papers. When the gap (separation) between the trailing edge of the preceding sheet SH1 and the leading edge of the succeeding sheet SH2 is detected when feeding the preceding sheet SH1, the sheet conveying unit 10 drives the pickup roller 101, the sheet feeding roller 102, and the separating roller 103, The feeding operation of the succeeding paper is started.

  Referring to FIG. 9, when the succeeding sheet SH1 is fed along with the preceding sheet SH1 when the preceding sheet SH1 is fed, the pickup roller 101 is used even though the pickup roller 101 is stopped. The leading edge of the succeeding paper SH2 protrudes further downstream. This follow-up state is released between the pickup roller 101 and the paper feed roller 102 and the separating roller 103 (FIG. 10), and is continued until just before the paper feeding roller 102 and the separating roller 103 (FIG. 11). In some cases, the paper feed roller 102 and the separating roller 103 and the vertical conveyance roller 104 are continued (FIG. 12).

  In the case of FIG. 10, a gap is generated between the trailing edge of the preceding sheet SH1 and the leading edge of the succeeding sheet SH2 between the pickup roller 101, the sheet feeding roller 102, and the separating roller 103. The light from the lamp 161 is received by the paper feed sensor 164 through a gap between the trailing edge of the preceding sheet SH1 and the leading edge of the succeeding sheet SH2. This light is indicated by an arrow L3 in FIG. As a result, the paper feed sensor unit 151 detects the gap between the papers, and the paper transport unit 10 drives the pickup roller 101, the paper feed roller 102, and the separating roller 103 to feed the succeeding paper SH2.

  In the case of FIG. 11, the feeding state is canceled by the action of the paper feed roller 102 and the separating roller 103, and immediately before the paper feeding roller 102 and the separating roller 103, the leading edge of the preceding sheet SH1 and the leading edge of the succeeding sheet SH2. A gap is created. The light from the lamp 161 is received by the paper feed sensor 164 through a gap between the trailing edge of the preceding sheet SH1 and the leading edge of the succeeding sheet SH2. This light is indicated by an arrow L4 in FIG. As a result, the paper feed sensor unit 151 detects the gap between the papers, and the paper transport unit 10 drives the pickup roller 101, the paper feed roller 102, and the separating roller 103 to feed the succeeding paper SH2.

  As shown in FIG. 12, even when the feeding state is not canceled by the action of the paper feeding roller 102 and the separating roller 103, the accompanying feeding is canceled between the feeding roller 102 and the separating roller 103 and the vertical conveying roller 104. When this occurs, the light from the lamp 161 is received by the paper feed sensor 164 through the gap between the trailing edge of the preceding paper SH1 and the leading edge of the succeeding paper SH2. This light is indicated by an arrow L5 in FIG. As a result, the paper feed sensor unit 151 detects the gap between the papers, and the paper transport unit 10 drives the pickup roller 101, the paper feed roller 102, and the separating roller 103 to feed the succeeding paper SH2.

  FIG. 13 is a time chart showing the operation state of each member when the succeeding paper is fed to the preceding paper when the preceding paper is fed. (A) is a graph showing the relationship between the paper position and time, and (b) is a graph showing the relationship between the output of the paper feed sensor and time. (C) is a graph showing the relationship between the drive state of the vertical conveying roller 104 and time, and (d) is a graph showing the relationship between the drive state of the pickup roller 101, the paper feed roller 102, and the separating roller 103 and time. It is. Note that the sheet position in FIG. 13A has a base point 0 at the nip portion of the pickup roller 101. Further, the position of the trailing edge of the preceding sheet is indicated by a graph GP1, and the position of the leading edge of the succeeding sheet is indicated by a graph GP2.

  Referring to FIG. 13, between time 0 and time T1, the leading edge of the succeeding sheet is on the downstream side of the trailing edge of the preceding sheet, and the leading edge of the succeeding sheet is moved to the downstream side. Move to. In addition, since the preceding sheet exists in the conveyance section A, the paper feed sensor unit 151 is in a state where no gap is detected. Further, the vertical conveying roller 104 is driven to drive the preceding paper, and since the feeding of the succeeding paper is not started, the pickup roller 101, the paper feeding roller 102, and the separating roller 103 are stopped.

  At time T1, when the leading paper and the following paper are released, the paper feed sensor unit 151 detects a gap between the paper, the pickup roller 101, the paper feed roller 102, and the roller 103 are driven, Start feeding the trailing paper. As a result, the succeeding sheet is conveyed with a slight gap from the preceding sheet.

  FIG. 14 is a flowchart illustrating a paper feed control process executed by the paper transport unit 10.

  Referring to FIG. 14, when a job using paper such as a print job or a copy job is received, paper transport unit 10 drives pickup roller 101, paper feed roller 102, and paper roller 103 (paper feed unit) ( S1), the conveyance of the preceding paper is started. Subsequently, the paper transport unit 10 determines whether or not a predetermined time TM has elapsed after the paper is detected by the vertical transport sensor 152 (S3).

  If it is determined in step S3 that the time has elapsed (YES in S3), the paper transport unit 10 determines that the transport of the preceding paper has been completed, and stops driving the paper feed unit (S5). Next, the paper transport unit 10 determines whether the paper feed sensor unit 151 has detected a gap between the papers (S7).

  If it is determined in step S7 that a gap has been detected (YES in S7), the paper transport unit 10 drives the paper feed unit (S9) and starts transporting subsequent paper. Thereafter, the paper transport unit 10 proceeds to the process of step S3.

[Second Embodiment]
FIG. 15 is a diagram illustrating a configuration of the transport path R in the vicinity of the paper feed sensor unit 151 when viewed from the horizontal direction of the transport path R in the second embodiment of the present invention. FIG. 16 is a diagram illustrating the configuration of the transport path R in the vicinity of the paper feed sensor unit 151 when viewed from the downstream side of the transport path R in the second embodiment of the present invention.

  Referring to FIGS. 15 and 16, MFP 1 in the present embodiment differs from the first embodiment in the configuration of paper feed sensor unit 151. The paper feed sensor unit 151 in the present embodiment includes a plurality of lamps 161a to 161e and a plurality of paper feed sensors 164a to 164c. Each of the plurality of lamps 161 a to 161 e is arranged in this order along the conveyance path R on the upper side in FIG. 15 of the conveyance path R (the upper side of the sheet SH being conveyed). Each of the paper feed sensors 164a to 164c is arranged in this order along the transport path R on the lower side of the transport path R in FIG. 15 (the lower side of the transported paper SH).

  The paper feed sensor unit 151 detects the presence or absence of a gap between sheets based on whether or not the light of the lamps 161a to 161e is received by the paper feed sensors 164a to 164c. Specifically, while the succeeding sheet is being carried along with the preceding sheet, the light from the lamps 161a to 161e is blocked by the preceding sheet and the following sheet, and the paper feed sensors 164a to 164c are from the lamps 161a to 161e. Not receive the light. On the other hand, when the trailing edge of the preceding sheet is separated from the leading edge of the succeeding sheet, the paper feed sensors 164a to 164c directly receive light from the lamps 161a to 161e inserted from the gap between the trailing edge of the preceding sheet and the leading edge of the trailing sheet. . By providing the lamps 161a to 161e and the paper feed sensors 164a to 164c at appropriate positions along the transport path R, the paper feed sensors 164a to 164c can detect the presence or absence of a gap in the entire transport section A.

  Since the configuration of the image forming apparatus other than that described above is the same as that of the image forming apparatus according to the first embodiment, the same members are denoted by the same reference numerals, and description thereof will not be repeated.

  Next, the operation of the sheet conveying unit 10 when conveying the preceding sheet and the succeeding sheet continuously will be described with reference to FIGS. In FIGS. 17 to 21, an arrow is attached to a driving roller, and an arrow is not attached to a stopped roller.

  With reference to FIG. 17, the preceding sheet SH <b> 1 is conveyed to the vertical conveyance roller 104 by the same method as in the first embodiment. When the vertical conveyance sensor 152 detects the preceding sheet SH1, the sheet conveyance unit 10 stops the driving of the pickup roller 101, the sheet feeding roller 102, and the separating roller 103. The preceding sheet SH1 is then transported using the vertical transport roller 104 as a drive source.

  When the succeeding sheet SH2 is not carried along with the preceding sheet SH1 when the preceding sheet SH1 is fed, the light of the lamp 161a is emitted from the trailing end of the preceding sheet SH1 at the moment when the trailing end of the preceding sheet SH1 leaves the pickup roller 101. And the leading edge of the succeeding sheet SH2, and is received by the sheet feed sensor 164a. This light is indicated by an arrow L6 in FIG. As a result, the paper feed sensor unit 151 detects the gap between the papers, and the paper transport unit 10 drives the pickup roller 101, the paper feed roller 102, and the separating roller 103 to feed the succeeding paper SH2.

  Referring to FIG. 18, when the succeeding sheet SH1 is fed to the preceding sheet SH1 when the preceding sheet SH1 is fed, the pickup roller 101 is used even though the pickup roller 101 is stopped. The leading edge of the succeeding paper SH2 protrudes further downstream. This follow-up state is released between the pickup roller 101 and the paper feed roller 102 and the separating roller 103 (FIG. 19), and when it continues until just before the paper feeding roller 102 and the separating roller 103 (FIG. 20). In some cases, the paper feed roller 102 and the separating roller 103 and the vertical conveyance roller 104 are continued (FIG. 21).

  In the case of FIG. 19, a gap is generated between the trailing edge of the preceding sheet SH1 and the leading edge of the succeeding sheet SH2 between the pickup roller 101, the sheet feeding roller 102, and the separating roller 103. Light from the lamp 161b or the like is received by the paper feed sensor 164a or 164b through a gap between the trailing edge of the preceding paper SH1 and the leading edge of the succeeding paper SH2. An example of this light is indicated by an arrow L7 in FIG. As a result, the paper feed sensor unit 151 detects the gap between the papers, and the paper transport unit 10 drives the pickup roller 101, the paper feed roller 102, and the separating roller 103 to feed the succeeding paper SH2.

  In the case of FIG. 20, the accompanying state is canceled by the action of the paper feed roller 102 and the separating roller 103, and immediately before the paper feeding roller 102 and the separating roller 103, the leading edge of the preceding sheet SH1 and the leading edge of the succeeding sheet SH2. A gap is created. Light from the lamp 161b or the like is received by the paper feed sensor 164b or the like through a gap between the trailing edge of the preceding sheet SH1 and the leading edge of the succeeding sheet SH2. An example of this light is indicated by an arrow L8 in FIG. As a result, the paper feed sensor unit 151 detects the gap between the papers, and the paper transport unit 10 drives the pickup roller 101, the paper feed roller 102, and the separating roller 103 to feed the succeeding paper SH2.

  As shown in FIG. 21, even if the feeding state is not canceled by the action of the paper feeding roller 102 and the separating roller 103, the feeding between the feeding roller 102 and the separating roller 103 and the vertical conveying roller 104 is eliminated. When this occurs, light such as the lamp 161c or 161d is received by the paper feed sensor 164b or 164c through the gap between the trailing edge of the preceding paper SH1 and the leading edge of the succeeding paper SH2. An example of this light is indicated by an arrow L9 in FIG. As a result, the paper feed sensor unit 151 detects the gap between the papers, and the paper transport unit 10 drives the pickup roller 101, the paper feed roller 102, and the separating roller 103 to feed the succeeding paper SH2.

  When detecting the presence or absence of a gap between the trailing edge of the preceding sheet SH1 and the leading edge of the following sheet SH2, the intensity (input value) of light received by the sheet feeding sensors 164a and 164b is set to 1 using the table shown in FIG. The pickup roller 101, the paper feed roller 102, and the separating roller 103 may be driven based on the combined 1-bit signal. 22 and 23, the paper feed sensor 1 is a paper feed sensor 164a, the paper feed sensor 2 is a paper feed sensor 164b, and the paper feed sensor 3 is a paper feed sensor 164c.

  Referring to FIG. 22, the intensity of light received by paper feed sensors 164a to 164c is binarized. When all of the paper feed sensors 164a to 164c are shielded from light by the paper, the intensity of light received by the paper feed sensors 164a to 164c is all “0” (low). In this case, a “0” signal is combined in positive logic, and a “1” (high) signal is combined in negative logic. As a result, the paper feed sensor unit 151 does not detect a gap between sheets.

  When the paper feed sensor 164a is shielded by the paper and the paper feed sensor 164b is not shielded by the paper, the intensity of the light received by the paper feed sensor 164a is “0”, and the light received by the paper feed sensor 164b. The strength of is “1”. In this case, a signal of “1” is combined in the positive logic and a signal of “0” is combined in the negative logic regardless of the state of the detection sensor 164c. As a result, the paper feed sensor unit 151 detects the gap between the papers, and the paper transport unit 10 starts driving the pickup roller 101, the paper feed roller 102, and the separating roller 103.

  When the paper feed sensor 164a is not shielded by the paper and the paper feed sensor 164b is shielded by the paper, the intensity of the light received by the paper feed sensor 164a is “1”, and the light received by the paper feed sensor 164b. The intensity of light is “0”. In this case, a signal of “1” is combined in the positive logic and a signal of “0” is combined in the negative logic regardless of the state of the detection sensor 164c. As a result, the paper feed sensor unit 151 detects the gap between the papers, and the paper transport unit 10 starts driving the pickup roller 101, the paper feed roller 102, and the separating roller 103.

  When neither of the paper feed sensors 164a and 164b is shielded by the paper, the intensity of the light received by the paper feed sensors 164a and 164b is “1”. In this case, a signal of “1” is combined in the positive logic and a signal of “0” is combined in the negative logic regardless of the state of the detection sensor 164c. As a result, the paper feed sensor unit 151 detects the gap between the papers, and the paper transport unit 10 starts driving the pickup roller 101, the paper feed roller 102, and the separating roller 103.

  FIG. 23 is a time chart showing the operation state of each member when the succeeding paper is fed to the preceding paper when the preceding paper is fed. (A) is a graph showing the relationship between the paper position and time, and (b) is a graph showing the relationship between the combined output of the paper feed sensors 1 and 2 and time. (C) is a graph showing the relationship between the drive state of the vertical conveying roller 104 and time, and (d) is a graph showing the relationship between the drive state of the pickup roller 101, the paper feed roller 102, and the separating roller 103 and time. It is. Note that the sheet position in FIG. 23A has a base point 0 at the nip portion of the pickup roller 101. Further, the position of the trailing edge of the preceding sheet is indicated by a graph GP1, and the position of the leading edge of the succeeding sheet is indicated by a graph GP2.

  Referring to FIG. 23, between time 0 and time T1, the leading edge of the succeeding sheet is downstream from the trailing edge of the preceding sheet, and the leading edge of the trailing sheet is moved downstream by the preceding sheet. Move to the side. In addition, since the preceding sheet exists in the conveyance section A, the paper feed sensor unit 151 is in a state where no gap is detected. Further, the vertical conveying roller 104 is driven to drive the preceding paper, and since the feeding of the succeeding paper is not started, the pickup roller 101, the paper feeding roller 102, and the separating roller 103 are stopped.

  At the time T1, when the preceding paper and the following paper are released, the combined output of the paper feed sensors 164a and 164b detects a gap between the paper, the pickup roller 101, the paper feed roller 102, and The separation roller 103 is driven to start feeding the succeeding paper. As a result, the succeeding sheet is conveyed with a slight gap from the preceding sheet.

  In the present embodiment, the case where the paper feed sensor unit 151 includes five lamps 161a to 161e and three paper feed sensors 164a to 164c has been described. It can be freely set according to the length and shape of A.

[Third Embodiment]
FIG. 24 is a diagram illustrating the configuration of the transport path R in the vicinity of the paper feed sensor unit 151 when viewed from the horizontal direction of the transport path R in the third embodiment of the present invention. FIG. 25 is a diagram illustrating a configuration of the transport path R in the vicinity of the paper feed sensor unit 151 when viewed from the downstream side of the transport path R in the third embodiment of the present invention.

  24 and 25, MFP 1 in the present embodiment is different from the first embodiment in the configuration of paper feed sensor unit 151. The paper feed sensor unit 151 in the present embodiment includes a lamp 161, a reflection plate 165 (an example of reflection means), a light collector 163, and a paper feed sensor 164. The lamp 161 is provided between the reflector 165 and the transport path R on the upper side of the transport path R in FIG. The reflection plate 165 is provided on the upper side in FIG. 24 of the transport path R, and reflects and irradiates the light of the lamp 161 in the vertical direction of the paper SH transported in the transport section A, for example. The light collector 163 is provided on the opposite side of the lamp 161 (lower side in FIG. 24) across the transport path R. The light collector 163 collects light from the lamp 161 that has passed through the gap between the trailing edge of the preceding paper and the leading edge of the succeeding paper when the trailing edge of the preceding paper is separated from the leading edge of the following paper. The paper feed sensor 164 is provided between the light collector 163 and the transport path R on the lower side of the transport path R in FIG. 24, and receives light collected by the light collector 163.

  The paper feed sensor unit 151 detects the presence or absence of a gap between sheets based on whether or not the light from the lamp 161 is received by the paper feed sensor 164. Specifically, while the succeeding sheet is being carried along with the preceding sheet, the light from the lamp 161 is shielded by the preceding sheet and the following sheet, and the sheet feed sensor 164 does not receive the light from the lamp 161. On the other hand, when the trailing edge of the preceding sheet is separated from the leading edge of the succeeding sheet, the paper feed sensor 164 receives light from the lamp 161 inserted through the gap between the trailing edge of the preceding sheet and the leading edge of the trailing sheet. By providing each of the lamp 161, the reflecting plate 165, the light collector 163, and the paper feed sensor 164 at appropriate positions along the transport path R, the paper feed sensor unit 151 detects the presence or absence of a gap in the entire transport section A. It is possible.

  The distance from the nip portion of the pick-up roller 101 to the nip portion between the paper feed roller 102 and the separating roller 103 (hereinafter sometimes referred to as distance 1) is, for example, 50 mm, and the distance between the paper feeding roller 102 and the separating roller 103 is The distance from the nip portion to the nip portion of the vertical conveyance roller 104 (hereinafter sometimes referred to as distance 2) is, for example, 80 mm, and the distance from the vertical conveyance roller 104 to the vertical conveyance sensor 152 (hereinafter referred to as distance 3). For example) is 10 mm. Further, the rotational speed of the pickup roller 101, the rotational speed of the paper feed roller 102, and the rotational speed of the separating roller 103 (hereinafter sometimes referred to as rotational speed 1) are equal to each other, for example, 100 mm / s. The rotational speed (hereinafter sometimes referred to as rotational speed 2) is 50 mm / s, for example. In other words, the speed at which the pickup roller 101, the paper feed roller 102, and the separating roller 103 feed the paper is higher than the speed at which the vertical transport roller 104 transports the paper. Further, the conveyed paper is, for example, A4 size (FD length of paper: 297 mm).

  Since the configuration of the image forming apparatus other than that described above is the same as that of the image forming apparatus according to the first embodiment, the same members are denoted by the same reference numerals, and description thereof will not be repeated.

  Next, the operation of the sheet transport unit 10 when the succeeding sheet is fed to the preceding sheet when the preceding sheet is fed will be described with reference to FIGS. 26 and 27. FIG.

  Referring to FIG. 26, the paper transport unit 10 specifies the position where the gap is generated based on the timing at which the paper feed sensor unit 151 detects the gap, and based on the specified position, the pickup roller 101 and the paper feed roller 102 and the roller 103 are driven. Specifically, the paper transport unit 10 detects the time from the time when the leading edge of the preceding paper SH1 is detected by the vertical transport sensor 152 to the time when the gap is detected by the paper feed sensor unit 151, and the paper by the vertical transport roller 104. The position where the gap between the sheets is generated is specified based on the speed at which the sheet is conveyed and the length of the sheet in the conveying direction (FD length of the sheet). Then, based on the specified position, the paper transport unit 10 sets a standby time from the time when the gap is detected to the time when the pickup roller 101, the paper feed roller 102, and the paper roller 103 are driven.

  When the vertical conveyance sensor 152 detects the leading edge of the preceding paper SH1, the paper conveyance unit 10 stops driving the pickup roller 101, the paper feed roller 102, and the paper roller 103. The preceding sheet SH1 is then transported using the vertical transport roller 104 as a drive source. A distance D1 from the trailing edge of the preceding sheet SH1 to the nip portion between the paper feeding roller 102 and the separating roller 103 when the preceding sheet SH1 is conveyed is expressed by the following equation (1). Time 1 is the elapsed time from the time when the leading edge of the preceding sheet SH1 is detected by the vertical conveyance sensor 152.

(Distance D1) = (FD length of paper) − (Distance 2 + Distance 3 + Rotation speed 2 × Time 1) = 297− (80 + 10 + 50 × Time 1 (s)) = 207−50 × Time 1 (s) ( 1)
However, in the formula (1), when the time 1 <3.14 (s), the trailing edge of the preceding sheet SH1 has not reached the nip portion of the pickup roller 101. Therefore, in the formula (1), the time 1> 3.14 (s). The distance from the nip portion of the pickup roller 101 to the nip portion of the vertical conveyance roller 104 (the length of the conveyance section A) is (distance 1) + (distance 2) + (distance 3) = 140 mm.

  When the paper feed sensor unit 151 detects the gap between the papers, the paper transport unit 10 waits for a time calculated by the following method, for example, and then picks up the pickup roller 101 and the paper feed to feed the succeeding paper SH2. The paper roller 102 and the separating roller 103 are driven. When the succeeding sheet SH2 is not carried along with the preceding sheet SH1, the sheet conveying unit 10 feeds the following sheet SH2 after waiting for the time determined by the following equation (2A) or (2B). .

Standby time (s) = (distance 1 + distance 2 + distance 3) / (rotational speed 1−rotational speed 2) = (50 + 80 + 10) ÷ (100−50) = 2.8 (s) (2A)
Standby time (s) = (distance 1 + distance 2 + distance 3) / (rotational speed 2) − (distance 1 + distance 2 + distance 3) / (rotational speed 1) = (50 + 80 + 10) ÷ (50) − (50 + 80 + 10) ÷ (50) = 2.8−1.4 = 1.4 (s) (2B)
Referring to FIG. 27, when the succeeding sheet SH1 is fed along with the preceding sheet SH1 when the preceding sheet SH1 is fed, the pickup roller 101 is used even though the pickup roller 101 is stopped. The leading edge of the succeeding sheet SH2 protrudes further to the downstream side. This follow-up state is released between the pickup roller 101 and the paper feed roller 102 and the separating roller 103, when it continues until just before the paper feeding roller 102 and the separating roller 103, and the paper feeding roller 102 and the separating roller. In some cases, it may continue to between 103 and the vertical conveying roller 104.

  When released between the pickup roller 101, the paper feed roller 102, and the separation roller 103, the distance from the rear end of the preceding paper SH1 to the nip portion between the paper supply roller 102 and the separation roller 103 when a gap occurs. Is a distance 4, and after waiting for the time determined by the following formula (3A) or formula (3B), the paper transport unit 10 feeds the succeeding paper SH2.

Standby time (s) = (distance 4 + distance 2 + distance 3) / (rotational speed 1−rotational speed 2) = (distance 4 + 80 + 10) ÷ (100−50) = (distance 4 + 90) ÷ 50 (3A)
Standby time (s) = (Distance 4 + Distance 2 + Distance 3) / (Rotational speed 2) − (Distance 4 + Distance 2 + Distance 3) ÷ (Rotational speed 1) = (Distance 4 + 80 + 10) ÷ 50− (Distance 4 + 80 + 10) ÷ 100 = (Distance 4 + 90) ÷ 50− (distance 4 + 90) ÷ 100 (3B)
The distance 4 is calculated from (Equation 1).

  When the feed state continues immediately before the paper feed roller 102 and the separation roller 103, the feed state is canceled by the action of the paper feed roller 102 and the separation roller 103. A gap is generated between the sheet SH1 and the succeeding sheet SH2. In this case, after waiting for the time determined by the following formula (4A) or (4B), the sheet transport unit 10 feeds the succeeding sheet SH2.

Standby time (s) = (distance 2 + distance 3) / (rotational speed 1−rotational speed 2) = (80 + 10) ÷ (100−50) = 1.8 (s) (4A)
Standby time (s) = (distance 2 + distance 3) ÷ (rotational speed 2) − (distance 2 + distance 3) ÷ (rotational speed 1) = (80 + 10) ÷ 50− (80 + 10) ÷ 100 = 0.9 (s) ... (4B)
In addition, Formula (4A) and Formula (4B) are equal to what set distance 4 to 0 in Formula (3A) and (3B).

  Even if the feed state is not canceled due to the action of the paper feed roller 102 and the separating roller 103, when the carry feed is canceled between the sheet feeding roller 102 and the separating roller 103 and the vertical conveying roller 104, the expression After waiting for the time calculated using (3A) or (3B), the paper transport unit 10 may feed the succeeding paper SH2.

  FIG. 28 is a table showing the relationship between the position where the carry is canceled and the standby time calculated from the above equation.

  Referring to FIG. 28, when the succeeding sheet SH2 is not carried along with the preceding sheet SH1, the standby time is 2.8 (s). When the feeding is canceled in the section from the nip portion of the pickup roller 101 to the nip portion of the paper feed roller 102 and the separating roller 103, the standby time is smaller than 2.8 (s) and from 1.8 (s). growing. When the follow-up is canceled at the nip portion between the sheet feeding roller 102 and the separating roller 103, the standby time is 1.8 (s). When the follow-up is canceled in the section from the nip portion between the paper feed roller 102 and the separating roller 103 to the nip portion of the vertical conveying roller 104, the standby time is shorter than 1.8 (s).

  FIG. 29 is a time chart showing the operation state of each member when the succeeding paper is fed to the preceding paper when the preceding paper is fed. (A) is a graph showing the relationship between the paper position and time, and (b) is a graph showing the relationship between the output of the paper feed sensor and time. (C) is a graph showing the relationship between the drive state of the vertical conveying roller 104 and time, and (d) is a graph showing the relationship between the drive state of the pickup roller 101, the paper feed roller 102, and the separating roller 103 and time. It is. Note that the time in FIG. 26 is based on the time when the vertical conveyance sensor 152 detects the leading edge of the preceding sheet SH1 as the base point 0. In addition, the sheet position in FIG. 29A is based on the nip portion of the pickup roller 101 as a base point (0). Further, the position of the trailing edge of the preceding sheet is indicated by a graph GP1, and the position of the leading edge of the succeeding sheet is indicated by a graph GP2. FIG. 30 is a table showing an example of the relationship between the time and the position of the trailing edge of the preceding sheet in the case of FIG.

  29 and 30, the trailing edge of the preceding sheet passes through the nip portion of pickup roller 101 at time T0. Between time T0 and time T1, the leading edge of the succeeding sheet is located downstream of the trailing edge of the preceding sheet, and the leading edge of the succeeding sheet moves to the downstream side as it is fed to the preceding sheet. Further, since the preceding sheet exists in the transport section A, the sheet feed sensor unit 151 is in a state where it does not detect the gap between the sheets. Further, the vertical conveying roller 104 is driven to drive the preceding paper, and since the feeding of the succeeding paper is not started, the pickup roller 101, the paper feeding roller 102, and the separating roller 103 are stopped.

  At time T <b> 1, the leading state of the preceding sheet and the succeeding sheet is released, and the sheet feeding sensor unit 151 detects the gap. When the paper feed sensor unit 151 detects the gap, the paper transport unit 10 stops driving the pickup roller 101, the paper feed roller 102, and the separating roller 103 during the calculated standby time (2.08 seconds in this case). . Thereby, the gap between the trailing edge of the preceding sheet and the leading edge of the succeeding sheet is widened. Then, at time T <b> 2 after the standby time elapses, the paper transport unit 10 drives the pickup roller 101, the paper feed roller 102, and the separating roller 103 to start feeding the succeeding paper. When the feeding of the succeeding paper is started, the gap between the trailing edge of the preceding sheet and the leading edge of the trailing sheet SH2 is narrowed due to the difference between the rotational speed 1 and the rotational speed 2, and at the time T3, the leading edge of the trailing sheet SH2 Pass through 152.

  FIG. 31 is a flowchart illustrating a paper feed control process executed by the paper transport unit 10.

  Referring to FIG. 31, when a job using paper such as a print job or a copy job is received, paper transport unit 10 drives pickup roller 101, paper feed roller 102, and paper roller 103 (paper feed unit) ( S101), the conveyance of the preceding paper is started. Subsequently, the paper transport unit 10 determines whether or not a predetermined time TM has elapsed after the paper is detected by the vertical transport sensor 152 (S103).

  If it is determined in step S103 that the time has elapsed (YES in S103), the paper transport unit 10 determines that the transport of the preceding paper has been completed, and stops driving the paper feed unit (S105). Next, the paper transport unit 10 determines whether or not the gap is detected by the paper feed sensor unit 151 (S107).

  If it is determined in step S107 that a gap has been detected (YES in S107), the paper transport unit 10 calculates the distance D1 using equation (1) and estimates the position of the gap (S109). Next, based on the position of the gap, the sheet conveying unit 10 calculates a waiting time until the conveyance of the succeeding sheet is started using, for example, Expression (3A) (S111). Subsequently, the paper transport unit 10 waits while stopping the feeding of the succeeding paper until the standby time elapses (S113). If the standby time has elapsed (YES in S115), the paper transport unit 10 proceeds to the process of step S101, and drives the paper feed unit to start feeding the succeeding paper (S101).

[Fourth Embodiment]
FIG. 32 is a diagram illustrating the configuration of the transport path R in the vicinity of the paper feed sensor unit 151 when viewed from the horizontal direction of the transport path R according to the fourth embodiment of the present invention. FIG. 33 is a diagram illustrating the configuration of the transport path R in the vicinity of the paper feed sensor unit 151 when viewed from the downstream side of the transport path R in the fourth embodiment of the present invention.

  Referring to FIG. 32 and FIG. 33, MFP 1 in the present embodiment is different from the first embodiment in the configuration of paper feed sensor unit 151. The paper feed sensor unit 151 in the present embodiment includes a plurality of lamps 161a to 161e and a paper feed sensor 164 that is a line sensor. Each of the plurality of lamps 161 a to 161 e is arranged in this order along the transport path R on the upper side in FIG. 32 of the transport path R (the upper side of the sheet SH being transported). The paper feed sensor 164 is arranged on the same side as the plurality of lamps 161a to 161e (upper side of the paper SH to be conveyed).

  The paper feed sensor unit 151 detects the presence or absence of a gap between the papers based on whether or not the light of the lamps 161a to 161e is received by the paper feed sensor 164. Specifically, while the succeeding sheet is being carried along with the preceding sheet, the light from the lamps 161a to 161e is reflected by the preceding sheet and the following sheet, and the paper feed sensor 164 reflects the reflected light of the lamps 161a to 161e. Receive. On the other hand, when the trailing edge of the preceding sheet is separated from the leading edge of the succeeding sheet, light from the lamps 161a to 161e leaks from the gap between the trailing edge of the preceding sheet and the leading edge of the succeeding sheet, and the sheet feeding sensor 164 has the lamps 161a to 161e. Does not receive the reflected light. By providing each of the lamps 161 a to 161 e and the paper feed sensor 164 at an appropriate position along the transport path R, the paper feed sensor unit 151 can detect the presence or absence of a gap in the entire transport section A.

  The paper feed sensor 164 can detect a gap between the trailing edge of the preceding paper and the leading edge of the succeeding paper SH2 when the amount of received light continues to decrease at ten or more of the elements constituting the paper feeding sensor 164. preferable. The paper feed sensor 164 preferably has a resolution of 0.1 mm pitch, for example.

  When detecting the presence or absence of a gap between the trailing edge of the preceding sheet and the leading edge of the succeeding sheet, the light intensity (input value) received by the sheet feeding sensor 164 is synthesized into a 1-bit signal using the table shown in FIG. The pickup roller 101, the paper feed roller 102, and the separating roller 103 may be driven based on the combined 1-bit signal.

  Referring to FIG. 34, the intensity of light received by paper feed sensor 164 is binarized. When the intensity of the reflected light received by the paper feed sensor 164 is higher than a predetermined threshold in all the sections (in the case of high), “1” is output from the paper feed sensor 164. In this case, a “0” signal is synthesized in the positive logic, and a “1” signal is synthesized in the negative logic. As a result, the paper feed sensor unit 151 does not detect a gap between sheets. On the other hand, when the intensity of the reflected light received by the paper feed sensor 164 is lower than a predetermined threshold value in a certain section (when low), the paper feed sensor 164 outputs “0”. In this case, a signal of “1” is synthesized in the positive logic, and a signal of “0” is synthesized in the negative logic. As a result, the paper feed sensor unit 151 detects the gap.

  Since the configuration of the image forming apparatus and the operation of the paper transport unit other than those described above are the same as those of the image forming apparatus and the paper transport unit in the first embodiment, the same members are denoted by the same reference numerals. The description will not be repeated.

[Fifth Embodiment]
FIG. 35 is a diagram illustrating the configuration of the transport path R in the vicinity of the paper feed sensor unit 151 when viewed from the horizontal direction of the transport path R in the fifth embodiment of the present invention. FIG. 36 is a diagram illustrating a configuration of the transport path R in the vicinity of the paper feed sensor unit 151 when viewed from the downstream side of the transport path R in the fifth embodiment of the present invention.

  Referring to FIGS. 35 and 36, in MFP 1 in the present embodiment, the configuration of paper feed sensor unit 151 is different from that in the first embodiment. The paper feed sensor unit 151 in the present embodiment includes a plurality of lamps 161a to 161e and a paper feed sensor 164 that is a line sensor. Each of the plurality of lamps 161 a to 161 e is arranged in this order along the conveyance path R on the upper side in FIG. 35 of the conveyance path R (the upper side of the sheet SH being conveyed). The paper feed sensor 164 is arranged in this order along the transport path R on the lower side of the transport path R in FIG. 35 (lower side of the transported paper SH).

  The paper feed sensor unit 151 detects the presence or absence of a gap between the papers based on whether or not the light of the lamps 161a to 161e is received by the paper feed sensor 164. Specifically, while the succeeding paper is being carried along with the preceding paper, the light from the lamps 161a to 161e is blocked by the preceding paper and the following paper, and the paper feed sensor 164 is light from the lamps 161a to 161e. Not receive. On the other hand, when the trailing edge of the preceding sheet is separated from the leading edge of the succeeding sheet, the paper feed sensor 164 receives light from the lamps 161a to 161e inserted from the gap between the trailing edge of the preceding sheet and the leading edge of the trailing sheet. By providing the lamps 161 a to 161 e and the paper feed sensor 164 at appropriate positions along the transport path R, the paper feed sensor 164 can detect the presence or absence of a gap in the entire transport section A.

  The paper feed sensor 164 preferably detects the gap between the trailing edge of the preceding sheet and the leading edge of the succeeding sheet when the amount of received light continues to decrease at ten or more of the elements constituting the sheet feeding sensor 164. . The paper feed sensor 164 preferably has a resolution of 0.1 mm pitch, for example.

  When detecting the presence or absence of a gap between the trailing edge of the preceding sheet and the leading edge of the succeeding sheet, the light intensity (input value) received by the sheet feeding sensor 164 is synthesized into a 1-bit signal using the table shown in FIG. The pickup roller 101, the paper feed roller 102, and the separating roller 103 may be driven based on the combined 1-bit signal.

  Referring to FIG. 37, the intensity of light received by paper feed sensor 164 is binarized. When the intensity of transmitted light received by the paper feed sensor 164 is lower than a predetermined threshold in all sections (in the case of low), “0” is output from the paper feed sensor 164. In this case, a “0” signal is synthesized in the positive logic, and a “1” signal is synthesized in the negative logic. As a result, the paper feed sensor unit 151 does not detect a gap between sheets. On the other hand, when the intensity of the reflected light received by the paper feed sensor 164 is higher than a predetermined threshold value in a certain section (when high), the paper feed sensor 164 outputs “1”. In this case, a signal of “1” is synthesized in the positive logic, and a signal of “0” is synthesized in the negative logic. As a result, the paper feed sensor unit 151 detects the gap.

  Since the configuration of the image forming apparatus other than that described above is the same as that of the image forming apparatus according to the first embodiment, the same members are denoted by the same reference numerals, and description thereof will not be repeated.

[Effect of the embodiment]
According to the above-described embodiment, since the pickup roller, the paper feed roller, and the roller are driven in synchronization based on the presence or absence of a gap between the papers in the transport section, the leading edge and the trailing edge of the preceding paper at the time of paper feeding are driven. It is possible to reduce the variation amount of the sheet interval from the leading end of the line sheet, and it is possible to reduce the sheet interval itself. As a result, the number of printed sheets for a predetermined time can be increased without changing the system speed, and the system speed can be decreased without changing the number of printed sheets. As a result, energy can be saved by reducing the output of the motor, and the paper can be conveyed efficiently.

  In addition, since it is not necessary to correct the gap between the trailing edge of the preceding sheet and the leading edge of the succeeding sheet during conveyance, the pickup roller and the feeding roller can be driven synchronously (simultaneous driving), Cost reduction, simplification of control, and downsizing of the apparatus can be achieved.

[Others]
In the above-described embodiment, the case where the paper feed sensor unit detects the presence or absence of a gap between sheets conveyed in the conveyance section A has been described. However, the paper feed sensor unit detects the presence or absence of a gap between the paper transported in the transport section and the next sheet at at least two points in the transport section from the position of the pickup roller to a position downstream of the paper feed roller. Anything to do.

  The above-described embodiments can be appropriately combined. For example, by combining the first embodiment and the fifth embodiment, the paper feed sensor unit may include a lamp, a diffusion plate, and a paper feed sensor that is a line sensor. In addition, in the configuration of the first, second, fourth, or fifth embodiment by combining the third embodiment with the first, second, fourth, or fifth embodiment, The conveyance of the subsequent sheet may be started after waiting for the time calculated in the third embodiment.

  The processing in the above-described embodiment may be performed by software or may be performed using a hardware circuit. In addition, a program for executing the processing in the above-described embodiment can be provided, and the program is recorded on a recording medium such as a CD-ROM, a flexible disk, a hard disk, a ROM, a RAM, and a memory card and provided to the user. You may decide to do it. The program is executed by a computer such as a CPU. The program may be downloaded to the apparatus via a communication line such as the Internet.

  The above-described embodiment is to be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 MFP
DESCRIPTION OF SYMBOLS 10 Paper conveyance part 20 Toner image formation part 30 Fixing part 40 Paper feeding apparatus 41 Paper discharge tray 51 Control part 52 Memory | storage part 101 Pickup roller 102 Paper feed roller 103 Rolling roller 104 Vertical conveyance roller 105 Timing roller 106 Paper discharge roller 151 Paper supply Sensor unit 152 Vertical conveyance sensor 153 Timing sensor 154 Loop sensor 155 Paper discharge sensor 161, 161a to 161e Lamp 162 Diffuser plate 163 Light collecting plate 164, 164a to 164c Paper feed sensor 165 Reflector plate 171a to 171c DC brushless motor 230 Intermediate transfer belt 240 Secondary transfer roller 310 Heating roller 320 Pressure roller A Conveying section R Conveying path SH paper SH1 Predecessor sheet SH2 Subsequent sheet

Claims (16)

A paper transport device comprising pick-up means for picking up paper and paper feeding means for separating and feeding the paper picked up by the pick-up means one by one,
Detecting means for detecting presence / absence of a gap between a sheet conveyed in the conveying section and a next sheet at at least two points in the conveying section from the position of the pickup means to a position downstream of the feeding means;
A sheet conveying apparatus comprising: a driving unit that drives the pickup unit and the feeding unit in synchronization based on the presence or absence of a gap detected by the detection unit.   The sheet conveying apparatus according to claim 1, wherein the detecting unit detects the presence or absence of a gap in the entire conveying section. A transport unit that transports the paper at a position downstream of the feeding unit and closest to the feeding unit;
The sheet conveying apparatus according to claim 1, wherein the detecting unit detects the presence or absence of a gap in a conveying section to the position of the conveying unit. Further comprising position specifying means for specifying the position where the gap is generated based on the timing at which the detecting means detects the gap;
The sheet conveying device according to claim 3, wherein the driving unit drives the pickup unit and the feeding unit based on the position specified by the position specifying unit. Paper detection means for detecting paper conveyed by the conveyance means,
When the speed at which the paper is fed by the feeding means is greater than the speed at which the paper is conveyed by the transport means, the position specifying means detects the time from the time when the paper detection means detects the leading edge of the paper Identifying the position where the interval is generated based on the time until the time when the gap is detected by the means, the speed at which the paper is transported by the transport means, and the length of the paper along the transport direction,
The driving means sets a waiting time from the time when the gap is detected by the detecting means to the time when the pickup means and the feeding means are driven based on the position specified by the position specifying means. The sheet conveying apparatus according to claim 4, comprising means.   The detecting means includes a light emitting means for emitting light and a light receiving means for receiving light from the light emitting means, and detects the presence or absence of a gap based on whether or not the light from the light emitting means is received by the light receiving means. The sheet conveying apparatus according to claim 1.   The paper conveying apparatus according to claim 6, wherein the detecting means further includes a diffusing means for diffusing the light of the light emitting means so that light is irradiated to the paper conveyed in the conveying section.   The paper conveying apparatus according to claim 6, wherein the detecting unit further includes a condensing unit that condenses the light of the light emitting unit onto the light receiving unit.   The paper transport apparatus according to claim 6, wherein the detection unit further includes a reflection unit that reflects the light of the light emitting unit and irradiates the paper transported in the transport section.   The light emitting means is provided on one side of the transport path of the paper, the light receiving means is provided on the other side of the transport path, and the light receiving means receives light transmitted through a gap between the paper and the next paper. The sheet conveying device according to claim 6. The light receiving means is a line sensor;
The paper conveying apparatus according to claim 10, wherein the detection unit detects a gap when the output of the line sensor is high in a certain section. The light receiving means is plural, and the detecting means is
An intensity acquisition means for acquiring, from the plurality of light receiving means, the intensity of light transmitted through the gap between the paper and the next paper when the trailing edge of the paper is separated from the leading edge of the next paper;
And further includes a combining unit that combines the intensity acquired by the intensity acquiring unit with a 1-bit signal.
12. The paper conveying apparatus according to claim 6, wherein the driving unit drives the pickup unit and the feeding unit based on the 1-bit signal synthesized by the synthesizing unit.   The paper transport device according to claim 6, wherein both of the light emitting unit and the light receiving unit are provided on one side of the paper transport path. The light receiving means is a line sensor;
The paper conveying apparatus according to claim 13, wherein the detection unit detects a gap when the output of the line sensor is low in a certain section. A control method for a paper transport device comprising pick-up means for picking up paper and paper-feeding means for separating and feeding the paper picked up by the pick-up means one by one,
A detection step of detecting the presence or absence of a gap between the sheet conveyed in the conveyance section and the next sheet at at least two points in the conveyance section from the position of the pickup means to a position downstream of the feeding means;
A control method for a sheet conveying device, comprising: a driving step for driving the pickup unit and the feeding unit in synchronization based on the presence or absence of a gap detected in the detection step. A control program for a paper transport device comprising pick-up means for picking up paper and feeding means for separating and feeding the paper picked up by the pick-up means one by one,
A detection step of detecting the presence or absence of a gap between the sheet conveyed in the conveyance section and the next sheet at at least two points in the conveyance section from the position of the pickup means to a position downstream of the feeding means;
A control program for a sheet conveying apparatus, which causes a computer to execute a driving step for driving the pickup unit and the feeding unit in synchronization based on the presence or absence of a gap detected in the detection step.

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