JP2014001061A - Paper feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow convergence of the quantity of air of a sheet levitation conveyance system at an optimum value, and to allow an automatic adjustment of the quantity of the air of the sheet levitation conveyance system instead of a manual adjustment.SOLUTION: A paper feeder includes: side end air blowing parts 20, 20 which blow side end air to a side face of a sheet placed on a sheet placing table 10; a front end air blowing part 70 which blows front end air to a front face of the sheet and separates the top-most level sheet from the next level sheet on the sheet placing table 10; a sheet suction conveyance part 40 which conveys the sheet piece by piece which is levitated by the side end air and separated from the front end air; a sending out detection sensor 12 which thereby detects the sheet being conveyed at a prescribed position; and a control part 50 which calculates paper feeding time from paper feeding start time when paper feeding starts by air blow of at least either the side end air or the front end air to sheet detection time, and controls the quantity of at least either the side end air or the front end air according to the calculation of the paper feeding time.

Description

  The present invention is an automatic adjustment function of side air, front end air, and suction air when air is blown to the side edges of a plurality of sheets loaded on a sheet placing table and the uppermost sheet that has floated is sent to the sheet conveyance path. The present invention relates to a paper feeding apparatus suitable for application to a large capacity paper feeding unit or the like having

  In recent years, according to the field of printing presses for commercial use and large-scale enterprises, large-capacity paper feeders are connected to image forming apparatuses such as color, black and white printers, copiers, and multi-function printers. Therefore, an image forming system that outputs a large amount of printed matter at high speed is used. A paper feeding device of such an image forming system is required to steadily send a large number of papers stacked on a paper placement table to the image forming device one by one at a high speed.

  For example, according to a paper feeding device equipped with a paper tray for floating air separation function, it is equipped with a paper mounting table, a side edge air blowing unit and a paper separating and conveying unit, and blows air from the side of the paper on the paper mounting table. The paper is floated, and the paper is separated and conveyed by a paper feed roller of a paper separation and conveyance unit provided above (see Patent Document 1).

  Generally, in a paper feeder equipped with a floating air separation function, the air flow of a blower fan connected to a side end air blowing section via a duct, the opening / closing of a shutter in the duct, etc. Means for adjusting the height are provided. The position of the side end air is adjusted by a mechanism that raises and lowers the position of the duct that blows out the air.

  In addition, a paper feeder equipped with a front-end air blowing unit has also been manufactured, and the strength of the side-end air is controlled by the air volume of a blower fan connected to the front-end air blowing unit via a duct, the opening and closing of a shutter in the duct, etc. Means for adjusting are provided.

  Furthermore, according to the paper feeder equipped with a paper feed tray for the floating air adsorption / conveyance function, it is equipped with a paper placement table, a side edge air blowing unit and a paper adsorption / conveyance unit, and blows air from the side of the paper on the paper placement table. Thus, the sheet is floated, and the sheet is sucked and transported by the suction means of the sheet suction and transport unit provided above. When the target of the floating sheet is a thin sheet, the sheet can be sucked only with the air of the sheet sucking and conveying unit. With thick paper, since the basis weight (weight per unit area) of the paper is large, the side end air is blown from the side surface.

JP 2010-037099 A

  By the way, according to the paper feeding device provided with the floating air separation function and the floating air adsorption / conveyance function found in Patent Document 1, the side edge air by the side edge air blowing unit and the front edge air are provided for each paper type. Manually change the amount of front-end air blown by the blowing unit and the air sucked and sucked by the paper suction conveyance unit, visually check the paper state, and if the paper floating state is inappropriate, blow the air again. Manual adjustment is performed until the amount is changed and the proper state is obtained.

  For this reason, every time the type of paper changes, it takes a lot of time to set the amount of air blown at the side edge, the amount of air blown at the front edge, the amount of air sucked in, and the like. For example, if the side edge air blowing amount is set to be small, the sheet floating operation is insufficient, the sheet is not fed, and the sheet feeding time is increased. If a large amount of side end air is blown, the sheet floating operation becomes excessive, resulting in double feeding in which two or more sheets are floated and conveyed.

  Moreover, despite the manual adjustment of the air blowing amount in the paper floating conveyance system such as the side edge air blowing part and the front edge air blowing part so as to obtain the optimum paper feeding conditions, the usage environment and the variation of the paper itself, etc. For this reason, the paper feed condition may deviate from the optimum setting value. Further, in the paper floating conveyance system, there is a problem that noise is generated if the front end air is set to an excessive side when fine adjustment is required for the amount of blowing front end air for each paper feed condition.

  Accordingly, the present invention solves the above-described problem, and allows the air flow rate of the paper floating conveyance system to converge to an optimum value, and the air flow rate of the paper floating conveyance system is manually adjusted. It is an object of the present invention to provide a paper feeding device that can be automatically adjusted without any problem.

  In order to solve the above-described problem, a sheet feeding device according to claim 1 includes: a first blowing unit that blows side-end air to a side surface of a sheet stacked on a sheet placing table that is movable in a vertical direction; and a sheet The front blower air is blown onto the front surface of the paper tray to separate the uppermost paper and the next paper from the paper mounting table, and the first blower floats up and is separated by the second blower. Paper is conveyed by blowing air from at least one of a conveyance unit that conveys the sheet one by one, a detection unit that detects a sheet conveyed by the conveyance unit at a predetermined position, and a first blowing unit and a second blowing unit. The paper feed time from the paper feed start time to the paper detection time when the paper is detected by the detection unit is calculated, and at least one of the side edge air and the front end air is calculated in accordance with the calculation of the paper feed time. And a control unit for controlling the amount of one Is shall.

  According to the paper feeding device of the first aspect, from the paper feeding start time when the control unit starts feeding the paper by blowing air from at least one of the first air blowing unit and the second air blowing unit, the detection unit Since the paper feed time up to the paper detection time when the paper is detected is calculated and the amount of at least one of the side end air and the front end air is controlled in accordance with the calculation of the paper feed time, The blowing air volume of at least one of the two air blowing units can be converged to an optimum value (feeding optimum condition). Accordingly, the blowing air volume of at least one of the side end air and the front end air can be automatically adjusted without manual adjustment.

  According to a second aspect of the present invention, in the paper feeding device according to the first aspect, the control unit measures the number of detections of the paper feeding time exceeding a predetermined ratio, and the number of detections of the paper feeding time exceeding the predetermined ratio; Comparing with the set threshold number of times set, the blowing air volume of at least one of the side end air and the front end air in each blowing unit corresponding to the comparison result of the number of detection times of the sheet feeding time and the threshold number of times It will increase or decrease.

  According to a third aspect of the present invention, in the paper feeding device according to the second aspect, when the number of times of detection of the paper feeding time exceeding the predetermined ratio is equal to or greater than a predetermined threshold number of times, the control unit Increase the amount of air blown by the side end air in the air blowing section, calculate the paper feed time from the paper feed start time after the side end air increase until the paper detection time, and the paper feed time before the side end air increase When the paper feeding time after the increase in the side end air is increased, the air blowing amount of the side end air in the first air blowing unit is decreased, and when the paper feeding time is reduced, the first air blowing unit. This increases the amount of air blown by the side end air.

  According to a fourth aspect of the present invention, in the paper feeding device according to the second aspect, when the number of times of detection of the paper feeding time exceeding a predetermined ratio is less than the threshold number, the control unit is configured to receive the side end of the first air blowing unit. Calculate the paper feed time from the paper feed start time after the reduction of the side edge air to the paper detection time by reducing the air blowing air volume, and compare that side edge with the paper feed time before the side edge air reduction. When the paper feeding time after the decrease in air increases, the amount of air blown by the side end air in the first blowing unit is increased, and when the paper feeding time decreases, the side end air blowing in the first blowing unit The air volume is reduced.

  According to a fifth aspect of the present invention, in the paper feeding device according to the second aspect, the control unit detects the front end air in the second air blowing unit when the number of detections of the paper feeding time exceeding a predetermined ratio is equal to or greater than the threshold number. After increasing the front-end air, calculate the paper-feed time from the paper feed start time after the front-end air increases until the paper detection time, and compare with the paper-feed time before the front-end air increases. When the sheet feeding time is increased, the front-end air blowing air volume in the second blowing unit is decreased. When the sheet feeding time is decreased, the front-end air blowing volume in the second blowing unit is increased. is there.

  According to a sixth aspect of the present invention, in the paper feeding device according to the second aspect, the control unit detects the front end air in the second air blowing unit when the number of times of detection of the paper feeding time exceeding a predetermined ratio is less than the threshold number of times. After reducing the front-end air, calculate the paper-feed time from the paper feed start time after the front-end air reduction to the paper detection time, and compared to the paper feed time before the front-end air reduction. When the sheet feeding time is increased, the front-end air blowing air volume in the second blowing unit is increased. When the sheet feeding time is decreased, the front-end air blowing volume in the second blowing unit is decreased. is there.

  According to a seventh aspect of the present invention, in the paper feeding device according to the first aspect, the transport unit sucks the sheets floating by the second air blowing unit one by one with the suction air, and the control unit calculates the feeding time. Correspondingly, the air volume of the suction air is controlled.

  According to an eighth aspect of the present invention, in the paper feeding device according to the seventh aspect, the control unit measures the number of detections of the paper feeding time exceeding a predetermined ratio, and the number of detections of the paper feeding time exceeding the predetermined ratio; A predetermined threshold number of times set is compared, and the air volume of the suction air in the transport unit is increased or decreased in accordance with the comparison result between the number of detection times of the paper feed time and the threshold number of times.

  According to a ninth aspect of the present invention, in the paper feeder according to the eighth aspect, when the number of times of detection of the paper feed time exceeding the predetermined ratio is equal to or greater than the threshold number, the control unit controls the air volume of the suction air in the transport unit. Calculate the paper feed time from the paper feed start time to the paper detection time after the suction air increases, and the paper feed time after the suction air increases compared to the paper feed time before the suction air increases Is increased, the air volume of the suction air in the transport section is decreased, and when the paper feeding time is decreased, the air volume of the suction air in the transport section is increased.

  According to a tenth aspect of the present invention, in the paper feeding device according to the eighth aspect, when the number of times of detection of the paper feeding time exceeding a predetermined ratio is less than the threshold number, the control unit controls the air volume of the suction air in the transport unit. Calculate the paper feed time from the paper feed start time after the suction air reduction to the paper detection time, and the paper feed time after the suction air reduction compared to the paper feed time before the suction air reduction Is increased, the air volume of the suction air in the transport section is increased. When the paper feed time is decreased, the air volume of the suction air in the transport section is decreased.

  According to the paper feeding device of the first aspect, it is possible to converge the blowing air volume of at least one of the first air blowing unit and the second air blowing unit to an optimum value (paper feeding optimum condition). Accordingly, the blowing air volume of at least one of the side end air and the front end air can be automatically adjusted without manual adjustment.

  According to the paper feeding device of the second aspect, the paper feeding starts to start paper feeding by blowing air from at least one of the first air blowing unit and the second air blowing unit of the uppermost paper on the paper placing table. With regard to the paper feed time from the time to the paper detection time in the paper detection unit, at least one of the first air blower and the second air blower is left with a predetermined margin with respect to the paper feed time until jam detection. It becomes possible to transport the sheets that are floated and separated by either one by one.

  According to the sheet feeding device according to the third and fourth aspects, it is possible to converge the blowing air volume of the side end air in the first air blowing unit to an optimum value. The sheet floated by the side air of the first air blower can be conveyed one by one with a margin of a predetermined ratio with respect to the paper feed time leading to jam detection.

  According to the sheet feeding device according to the fifth and sixth aspects, it is possible to converge the blowing air volume of the front end air in the second air blowing unit to an optimum value. Therefore, the front-end air blowing air volume can be automatically adjusted without manual adjustment. The sheet separated by the front end air of the second air blower can be conveyed one by one, leaving a predetermined ratio of margin relative to the paper feed time leading to jam detection.

  According to the paper feeding device of the seventh aspect, it is possible to converge the air volume of the suction air in the transport unit that sucks and transports the paper to the optimum value, and automatically adjusts the air volume of the suction air without manual adjustment. become able to.

  According to the sheet feeding device according to claims 8 to 10, regarding the sheet feeding time from the sheet feeding start time in the side edge air blowing unit of the uppermost sheet of the sheet placing table to the sheet detection time in the sheet detecting unit, Sheets that are levitated by the first air blowing unit, separated by the second air blowing unit, and adsorbed by the conveyance unit can be conveyed one sheet at a time with a margin of a predetermined ratio with respect to the paper feed time leading to jam detection. It becomes like this. As a result, a highly reliable large-capacity paper feeder (PFU) or the like can be provided.

1 is a cross-sectional view illustrating an overall configuration example of a sheet feeding device 100 as each embodiment according to the present invention. 3 is a perspective view illustrating a configuration example of a sheet suction conveyance system of a sheet feeding unit 101. FIG. FIG. 10 is a perspective view illustrating a configuration example of a sheet floating conveyance system of a sheet feeding unit 201 as a modified example. 3 is a block diagram illustrating a configuration example of a control system of the sheet feeding device 100. FIG. 3 is a flowchart illustrating an example of control of the sheet feeding device 100 as the first embodiment. It is a graph which shows the example of a relationship between the front end (sputtering) air amount and the paper feed time. 10 is a flowchart illustrating a control example of the sheet feeding device 100 according to the second embodiment. 10 is a flowchart illustrating a control example of a sheet feeding device 100 as a third embodiment.

  Hereinafter, a configuration example, an operation example, and a control example of a sheet feeding device as first to third embodiments of the present invention will be described with reference to the drawings. The descriptions in this section do not limit the technical scope described in the claims or the meaning of terms.

<First Embodiment>
First, a configuration example of the sheet feeding device 100 as each embodiment will be described with reference to FIGS. A paper feeding device 100 shown in FIG. 1 can be used by being connected to an image forming apparatus 200. The sheet feeding device 100 includes an apparatus main body 104. In the apparatus main body 104, for example, three sheet feeding units 101, 102, and 103, a control unit 50, and a sheet conveyance path 80 are provided. The sheet feeding device 100 is configured to send the sheets P stacked on the sheet feeding unit 101, 102, or 103 to the image forming apparatus 200 one by one based on a predetermined control mode by the control unit 50.

  The sheet feeding unit 101 includes, for example, a sheet loading table 10, side end air blowing units 20 and 20, a sheet suction conveyance unit 40, and a blowing port lifting / lowering unit 60. In the sheet feeding unit 101, the sheet loading table 10 is loaded with a plurality of sheets P and is movable in the vertical direction z. A lift mechanism (not shown) is attached to the paper mounting table 10. The elevating mechanism moves up and down so that the uppermost sheet P loaded on the sheet placing table 10 is maintained at a predetermined position.

  On both sides (left and right sides) of the paper mounting table 10, a pair of side end air blowing parts 20, 20, which is an example of a first air blowing part, are provided, and air (hereinafter referred to as side edges) is provided on the side edge of the paper P. The air 1a and 1b) are also blown. Each of the side-end air blowing units 20 and 20 is disposed on the side surface of the paper P stacked on the paper mounting table 10 with reference to the paper conveyance direction I (= y) shown in FIG. In the width direction x (direction substantially perpendicular to the conveyance direction y of the paper P), the side end air 1a and 1b for floating the paper P above the paper placement table 10 (vertical direction z perpendicular to xy) Air is blown from (width direction x).

  Each of the side end air blowing parts 20, 20 has a main body duct part 21, a sliding duct 22, a blowing port raising / lowering part 60 and the like. The main body duct portion 21 and the sliding duct 22 guide the side end air 1a, 1b for sheet floating to the side end air blowing port. An R-shaped guide portion 23 is provided on the upper side of the side-end air blowing port, and side-end air 1a and 1b is blown to each side edge of the paper P as indicated by white arrows in FIG.

  As a result, the paper P positioned at the top of the paper mounting table 10 is separated from the next paper P and floats by the side end air 1a, 1b blown to the side edge of the paper P. A blowing port raising / lowering unit 60 is provided on the back of each of the side end air blowing units 20, 20. The blowing port elevating unit 60 switches the side end air blowing port that defines the blowing position of the side end air 1a, 1b in the vertical direction z.

  The sheet adsorbing and conveying unit 40 is disposed above the sheet P loaded on the sheet placing table 10 and adsorbs the sheet P floating by the side end air 1a and 1b one by one by the suction air 3 (see FIG. 2). Then transport. The sheet suction conveyance unit 40 is provided with a pair of conveyance belts 41 and 41. The conveyor belts 41 and 41 suck the sheets P stacked on the sheet feeding unit 101 based on a predetermined control mode, and send the sheets P to the image forming apparatus 200 one by one.

  In the paper conveyance path 80 on the downstream side of the paper suction conveyance unit 40, a delivery detection sensor 12 constituting an example of a paper detection unit is disposed. The delivery detection sensor 12 detects the leading end of the paper P delivered from the paper suction conveyance unit 40 and generates a delivery detection signal. The delivery detection signal is output to the control unit 50.

  In addition, the sheet mounting table 10, the side air blowing units 20 and 20, the sheet suction conveyance unit 40, and the blowing port lifting / lowering unit 60 described above constitute a sheet adsorption conveyance system in the sheet feeding device 100. Reference numeral 103 also includes a paper suction conveyance system similar to that of the paper supply unit 101, and thus description thereof is omitted.

  The image forming apparatus 200 shown in FIG. 1 is connected to the sheet feeding apparatus 100 described above. The image forming apparatus 200 includes an image forming unit 90 for forming an image on the paper P fed from the paper feeding unit 101, 102, or 103. For the image forming unit 90, for example, an electrophotographic tandem color printer is used.

  Here, with reference to FIG. 3, a sheet separating and conveying unit 30 as a modified example of the sheet feeding device 100 will be described. 3 is provided in the paper feeding unit 201, and is disposed above the paper P stacked on the above-described paper mounting table 10 in place of the paper suction conveyance unit 40 shown in FIG. The sheets floated by the side-end air blowing sections 20 and 20 are separated and conveyed one by one. The sheet separating and conveying unit 30 includes, for example, a sheet feeding roller 31 and a separating roller 32.

  The paper feed roller 31 is disposed above the paper P stacked on the paper placement table 10 and is brought into pressure contact with the uppermost paper P with a predetermined pressure. A separation roller 32 is disposed on the downstream side (front end side in the feed direction of the paper P) adjacent to the outlet side of the paper feed roller 31, and regulates the rear end portion of the paper P fed by the paper feed roller 31. The second and subsequent sheets P are pushed back, and only one sheet P is sent into the main body of the image forming apparatus 200.

  The above-described paper mounting table 10, the side-end air blowing units 20, 20, the paper separating / conveying unit 30 and the blowing port lifting / lowering unit 60 constitute a paper floating conveyance system in the paper feeding device 100, and the other paper feeding units 102, 103 is also configured by a sheet floating conveyance system similar to the above-described sheet feeding unit 201, and thus description thereof is omitted.

  Next, a configuration example of a control system of the sheet feeding device 100 will be described with reference to FIG. The control system of the sheet feeding device 100 shown in FIG. 4 is common to each embodiment. For example, the feed detection sensor 12, the mounting table elevating drive unit 13, the operation display unit 48, the control unit 50, the blower fans 65 and 74, and elevating Motor 66 and a paper transporting portion 81. 2 is provided with the suction fan 77, the belt driving unit 42b, and the suction detection sensor 11, and when the paper separating and conveying unit 30 described in FIG. 3 is provided, the roller driving unit 33 is provided. Is provided.

  The loading table raising / lowering drive unit 13 is connected to the control unit 50, and is configured to raise and lower the sheet loading table 10 in the vertical direction z based on the loading table control signal S13 and the position detection signal obtained from the position detection sensor. In addition to the mounting table elevating drive unit 13, a blower fan 65 and an elevating motor 66 are connected to the control unit 50. The blower fan 65 and the raising / lowering motor 66 are provided in the side end air blowing portions 20 and 20, and the blower fan 65 generates the side end air 1a and 1b based on the blower control signal S65, and the main body duct shown in FIG. It operates so as to send side end air 1a, 1b having a predetermined blowing air volume to the part 21 and the sliding duct 22.

  The raising / lowering motor 66 is provided in the blowing port raising / lowering part 60, generate | occur | produces a rotational force based on the blowing port raising / lowering control signal S66, and raises / lowers the sliding duct 22 to the up-down direction z. A roller driving unit 33 is connected to the control unit 50. The roller driving unit 33 is provided in the paper separating / conveying unit 30 and drives the paper feeding roller 31 and the separating roller 32 of the paper separating / conveying unit 30 based on the roller control signal S33.

  In addition to the roller drive unit 33, the suction detection sensor 11 is connected to the control unit 50. The suction detection sensor 11 detects the paper P sucked by the paper suction conveyance unit 40 and outputs a suction detection signal S11 to the control unit 50. A suction fan 77 is connected to the control unit 50. The suction fan 77 is provided in the sheet suction conveyance unit 40, and sucks air in a suction chamber (not shown) based on the suction control signal S77, makes the suction chamber a negative pressure, and floats by the side air 1a and 1b. It operates to suck the paper P. At that time, the suction fan 77 sucks out the suction air 3 having a predetermined air volume from the suction chamber. A belt driving unit 42b is connected to the control unit 50. The belt driving unit 42b is provided in the paper suction conveyance unit 40, and drives the paper suction conveyance unit 40 based on the belt control signal S42.

  The feed detection sensor 12 and the paper transport unit 81 are provided in the paper transport path 80, and each is connected to the control unit 50. The delivery detection sensor 12 detects the paper P delivered from the paper separation transport unit 30 or the paper suction transport unit 40 to the paper transport path 80 and outputs a feed detection signal S12 (paper delivery information) to the control unit 50. Based on the paper transport control signal S80, the paper transport unit 81 controls a transport motor (not shown) in the paper transport path 80 to rotate the transport roller and transport the paper P toward the image forming apparatus 200. Then, a solenoid (not shown) is controlled to drive the conveyance path switching mechanism to select the paper feed unit 101, 102 or 103.

  A blower fan 74 is connected to the control unit 50. The blower fan 74 is provided in the front end air blowing unit 70, generates the front end air 2 (see FIGS. 2 and 3) based on the blow control signal S74, and sends the front end air 2 having a predetermined blowing air volume to the front end air blowing unit 70. Operates to send.

The control unit 50 constitutes a computer system, which receives a feed detection signal S12 of the paper P from the feed detection sensor 12, and based on the feed detection signal S12, the side end air blowing units 20, 20, the blowing port elevating unit 60, the front end air. Each of the spraying unit 70 and the suction fan 77 is controlled. The control unit 50 includes, for example, an oscillator 51, a memory unit 52, a central processing unit (hereinafter referred to as CPU 55), a timer 56, counters 57a and 57b, and a timing generation unit 58.

  The oscillator 51 generates a clock reference signal (hereinafter referred to as a CLK signal) having a predetermined operating frequency, and supplies the CLK signal to the memory unit 52, the CPU 55, the timer 56, the counters 57a and 57b, the timing generation unit 58, and the like. A memory unit 52 is connected to the CPU 55. For the memory unit 52, a RAM, a ROM, a fixed magnetic disk (HDD), or the like is used. The memory unit 52 stores a control program (control data D52) for executing the control mode. A control program is read in accordance with the control mode setting.

  The CPU 55 is connected with a jam detecting timer 56 and counters 57a and 57b for counting the number of times. The timer 56 generates a timer signal (time value) based on the CLK signal and outputs it to the CPU 55. The counter 57a is a paper feed time T from the paper feed start time t0 to the feed detection time tx in the feed detection sensor 12, and indicates the number N of detections of the paper feed time T that exceeds 50% of the jam detection time Tj. Measure based on CLK signal and timer signal.

  Here, the paper feed start time t0 is a time when the paper P starts to be fed by blowing air from at least one of the side end air blowing units 20 and 20 and the front end air blowing unit 70, and the jam detection time Tj is A paper feed time from the paper feed start time t0 to jam detection (second embodiment). The counter 57b measures the number of detections N of the paper feed time T exceeding 80% of the jam detection time Tj based on the CLK signal and the timer signal (first embodiment).

  In this example, the CPU 55 compares the detection number N of the paper feed time T exceeding 80% of the jam detection time Tj with a predetermined threshold number Nth set by the user, and detects the number of detections of the paper feed time T. Corresponding to the comparison result between N and the threshold number Nth, the amount of blowing air of the side end air 1a, 1b in the side end air blowing portions 20, 20 is increased or decreased. As the threshold number Nth, for example, any one of 3 to 7 times (5 ± 2 times) is selected and set in the CPU 55.

  Based on the control data D52 and the CLK signal, the timing generator 58 is based on the mounting table control signal S13, the roller control signal S33, the belt control signal S42, the air blowing control signal S65, the blowing port elevation control signal S66, the air blowing control signal S74, and the suction control. A signal S77 and a paper transport control signal S80 are generated.

  The placement table control signal S13 is a signal for controlling the sheet placement table 10, and is output from the timing generator 58 to the placement table raising / lowering drive unit 13. The roller control signal S33 is a signal for controlling the sheet separating and conveying unit 30 and is output from the timing generating unit 58 to the roller driving unit 33. The belt control signal S42 is a signal for controlling the rotation of the conveyance belts 41 and 41 of the paper suction conveyance unit 40, and is output from the timing generation unit 58 to the belt drive unit 42b.

  The air blowing control signal S65 is a signal for controlling the side end air blowing units 20 and 20, and is output from the timing generating unit 58 to the air blowing fan 65. The blowing port lifting / lowering control signal S66 is a signal for controlling the blowing port lifting / lowering unit 60, and is output from the timing generation unit 58 to the lifting / lowering motor 66. The air blow control signal S74 is a signal for controlling the front end air amount Qf for paper separation in the front end air blowing unit 70, and is output from the timing generation unit 58 to the blower fan 74.

  The suction control signal S77 is a signal for controlling the amount of suction air for paper suction in the paper suction transport unit 40, and is output from the timing generator 58 to the suction fan 77. The paper transport control signal S80 is a signal for controlling the transport of the paper P in the paper transport path 80, and is output from the timing generation unit 58 to the paper transport unit 81.

  An operation display unit 48 is connected to the control unit 50. For example, the operation display unit 48 is operated so as to set a control target value X based on a jam detection time Tj (100%). The user operates the operation display unit 48 to set, for example, the control target value X = 50%, 80%, or the like, or set the threshold number Nth = 5. Of course, the operation display unit 48 is operated when the paper feed unit 101, 102, or 103 is selected in addition to the control target value X, the threshold number Nth, and the like. The control target value X, the threshold number Nth, and the selection instruction for the paper feed unit 101, 102, or 103 are output as operation data D48 from the operation display unit 48 to the control unit 50. Thus, a control system of the sheet feeding device 100 is configured.

  In this example, the image forming apparatus 200 is connected to the sheet feeding apparatus 100 via a communication unit. The image forming apparatus 200 includes a CPU 95 in addition to the image forming unit 90. The control unit 50 of the sheet feeding device 100 and the control unit 91 of the image forming apparatus 200 can exchange information with each other via a communication modem (not shown) or a communication unit such as a communication interface. For example, by operating the operation display unit 98 connected to the control unit 91, at the time of initial setting, the control target value X based on the jam detection time Tj (100%) is set as 50% or 80%, The threshold number Nth may be set to 5 times, or an operation for instructing selection of the paper feed unit 101, 102, or 103 may be performed.

  Next, a control example of the sheet feeding device 100 as the first embodiment will be described with reference to FIG. According to the control example of the sheet feeding device 100 as the first embodiment, the front end air 2 and the suction air 3 are kept constant, and the side end air 1a and 1b are adjusted, and step ST1 shown in FIG. Then, the CPU 55 executes initial setting. At this time, the CPU 55 inputs the operation data D48 from the operation display unit 48, the operation display unit 98, etc., and sets the control target value X = 80% based on the jam detection time Tj (100%) based on the operation data D48. For example, the threshold number Nth = 5 is set, or the paper feeding unit 101 is selected. In step ST2, the CPU 55 receives the paper feed operation start signal and executes the paper feed operation. The control unit 50 receives the paper feed operation start signal from the image forming apparatus 200 via the communication unit.

  In step ST3, the CPU 55 starts measuring the paper feed time T. For example, the CPU 55 starts the timer 56 when the paper feed operation start signal rises. The start time of the timer 56 becomes the paper feed start time t0 in the side end air blowing units 20 and 20. Further, when the leading edge of the paper passes the feed detection sensor 12, the feed detection sensor 12 is turned on from OFF. The transition time from OFF to ON of the delivery detection sensor 12 is the delivery detection time t1. The paper feed time T is obtained from a timer signal depending on the number of pulses of the CLK signal from the paper feed start time t0 to the feed detection time t1.

  In step ST4, the CPU 55 determines whether or not a paper feed time T exceeding 80% of the jam detection time Tj has been detected, and branches the control. The determination criterion at this time is determined by comparing the paper feed time T = 0.8 · Tj which is 80% of the jam detection time Tj with the paper feed time T from the paper feed start time t0 to the feed detection time t1. To do.

  If the paper feed time T is 80% or less of the jam detection time Tj, the paper feed operation has changed with a margin of 20% from the feed detection time tx to the jam detection time Tj. Perform print job completion determination. The print job end determination is performed by, for example, receiving a print end flag (EOF) from the image forming apparatus 200 and detecting the EOF. When the EOF of the print job is detected, the paper feed control ends. If the EOF of the print job is not detected, the process returns to step ST2 to continue the paper feeding operation.

  In step ST4, if the CPU 55 detects a paper feed time T that exceeds 80% of the jam detection time Tj, the CPU 55 proceeds to step ST6, and the CPU 55 activates the counter 57b to make 80% of the jam detection time Tj. Control is performed so as to count the number of times N of detection of the paper feed time T exceeding. The counter 57b measures the number N of detections of the paper feed time T exceeding 80% of the jam detection time Tj based on the CLK signal and the timer signal.

  Thereafter, in step ST7, the CPU 55 determines whether or not the number N of detections of the paper feed time T exceeding 80% of the jam detection time Tj is equal to or greater than the threshold number Nth = 5, and branches the control. In this case, the criterion is that the number N of detection of the paper feed time T exceeding 80% of the jam detection time Tj is compared with the threshold number Nth = 5 set by the user, and the detection number N is the threshold number. This is performed by detecting whether Nth = less than 5 times or whether the number of detection times N is equal to or greater than the threshold number Nth = 5 times.

  If the number N of detections of the paper feed time T exceeding 80% of the jam detection time Tj is less than the threshold number Nth = 5, the process returns to step ST2 and the paper feed operation (control) is continued. If the number N of detections of the paper feed time T that exceeds 80% of the jam detection time Tj is equal to or greater than the threshold number Nth = 5, the CPU 55 increases the blowing air volume of the side air 1a and 1b in step ST8.

  In step ST9, the CPU 55 measures the paper feed time T1 after the increase in the air volume of the side end air 1a, 1b (see step ST3). Thereafter, in step ST10, the CPU 55 determines whether or not the paper feed time T1 after the increase in the air volume of the side air 1a and 1b exceeds 80% of the jam detection time Tj, and branches the control. The discrimination criterion at this time is the same as in step ST4. If the paper feed time T1 after the increase in the air volume of the side end air 1a, 1b is 80% or less of the jam detection time Tj, the process returns to step ST2 to continue the paper feed operation (control).

  In step ST10, if the paper feeding time T1 after the increase in the air volume of the side air 1a, 1b exceeds 80% of the jam detection time Tj, the CPU 55 determines in step ST11 that the air volume after the increase in the air volume of the side air 1a, 1b. The paper feed time T1 is compared with the paper feed time T0 before the air volume increase, and the control is branched based on the comparison result. If the paper feed time T1 after the increase in the air volume of the side air 1a, 1b is equal to or shorter than the paper feed time T0 before the increase in the air volume (T1 ≦ T0), the process returns to step ST8 and the blowing air volume of the side air 1a, 1b. Increase. If the paper feed time T1 after the increase in the air volume of the side air 1a, 1b exceeds the paper feed time T0 before the air volume increase (T1> T0), the process proceeds to step ST12 and the side air 1a, 1b is blown. Reduce airflow.

  As described above, according to the sheet feeding device 100 as the first embodiment, it is possible to converge the blowing air volume of the side end air 1a and 1b in the side end air blowing units 20 and 20 to an optimum value. Therefore, it becomes possible to automatically adjust the blowing air volume of the side end air 1a, 1b without manual adjustment. This makes it possible to provide a high-reliability large-capacity paper feeder (PFU) and the like.

  In the above-described embodiment, the case of increasing the blowing air volume of the side end air 1a, 1b has been described, but the present invention is not limited to this. Of course, the side edge in the side edge air blowing sections 20 and 20 corresponds to the comparison result between the number N of detection of the paper feed time T exceeding 80% of the jam detection time Tj and the set threshold number Nth = 5. The same effect can be obtained when the amount of air blown by the air 1a, 1b is reduced.

  In that case, a change (increase / decrease) in the paper feed time T from the paper feed start time t0 before and after the reduction of the side end air 1a, 1b to the delivery detection time tx is detected, and the side end air 1a, 1b decreases. When the paper feed time T1 after the decrease of the side end air 1a, 1b is increased as compared with the previous paper feed time T0, the amount of air blown by the side end air 1a, 1b in the side end air blowing units 20, 20 is increased. . Further, when the paper feed time T1 is reduced as compared with the paper feed time T0 before the decrease, the amount of air blown from the side end air 1a, 1b in the side end air blowing units 20, 20 is reduced. Even when the air amount is controlled in this way, the sheet that is levitated by the side-end air blowing units 20 and 20 is left as 1 with a margin of (100-80) = 20% with respect to the jam detection time Tj. It becomes possible to separate and convey each sheet.

<Second Embodiment>
Next, a control example of the sheet feeding device 100 as the second embodiment will be described with reference to FIGS. 6 and 7. In the example of the relationship between the front end (spreading) air amount Qf and the paper feed time shown in FIG. 6, the vertical axis is the paper feed time T [sec]. The paper feed time T is the movement time of the paper P from the paper feed start time t0 in the side edge air blowing units 20 and 20 of the uppermost paper P of the paper placement table 10 to the feed detection time tx in the feed detection sensor 12. It is. The horizontal axis represents the front end air amount Qf [m ³ / s]. The front end air amount Qf is a blowing air amount of the front end air 2 blown from the front end air blowing unit 70 to the leading end of the uppermost sheet P of the sheet placing table 10.

  An L-shaped curve (substantially exponential function curve) indicated by a solid line is a plot of an example of the relationship between the front end air amount and the paper feed time T. In this example, the front end air amount Qf is “low” on the left end side of the horizontal axis, and the front end air amount Qf is “high” on the right end side. As the front end air amount Qf decreases, the floating operation of the paper P becomes more aggressive (excessive), resulting in double feeding and a transition to a direction in which the paper feeding time T becomes longer. That is, if the front end air 2 is insufficient, the double feed state of the paper P is prolonged, the paper feed time T is increased (the paper feed speed is decreased), and jamming is ultimately caused. As the front end air amount Qf increases, the flying operation sound (noise) of the paper P increases, but the paper feeding time T decreases.

  Tj in the paper feed time T on the vertical axis is the jam detection time described in the first embodiment. Further, the satin portion in the graph is an area showing the relationship between the front end air amount Qf exceeding the jam detection time Tj (100%) and the paper feed time T, and is an area where the paper P is handled as a jam (JAM). is there.

  In this example, two control target values X1 and X2 are set with reference to the jam detection time Tj (100%), and paper feed control is performed. For example, 80% is set as the control target value X1. When X1 = 80%, there is a 20% margin from the delivery detection time tx to the jam detection time Tj. In the figure, the front end air amount Qf when X1 = 80% is indicated by Q80.

  50% is set as the control target value X2. In the case of X2 = 50%, a margin of 50% is expected from the feed detection time tx to the jam detection time Tj. In the figure, the front end air amount Qf when X2 = 50% is indicated by Q50 (Q80 <Q50). In this example, the control target values X1 and X2 are set based on the upper and lower limits of the jam detection time Tj, the front end air amount Qf is set in the range of Q80 <Q50, and the paper feed control is executed within this range. It is.

  Next, a control flowchart of the sheet feeding device 100 will be described with reference to FIG. In this embodiment, the side end air 1a, 1b and the suction air 3 are kept constant, and the front end air 2 is adjusted. The control target value X1 = 80% based on the jam detection time Tj (100%). , X2 = 50%, threshold number Nth = 5 is set, and the sheet feeder 201 is selected to control the sheet feeder 100.

  First, in step ST21 shown in FIG. 7, the CPU 55 performs initial setting. At this time, the CPU 55 inputs the operation data D48 from the operation display unit 48 or the like, and sets the control target values X1 = 80% and X2 = 50% based on the jam detection time Tj (100%) based on the operation data D48. The threshold number Nth = 5 times is set, or the paper feeding unit 201 is selected. In step ST22, the CPU 55 receives the paper feed operation start signal and executes the paper feed operation. The sheet feeding operation start signal is received by the control unit 50 from the image forming apparatus 200 by starting the communication unit.

  In step ST23, the CPU 55 starts measuring the paper feed time T. For the measurement of the paper feed time T, refer to step ST3 of the first embodiment. Thereafter, in step ST24, the CPU 55 branches the control based on whether or not the paper feed time T has exceeded 80% of the jam detection time Tj. Refer to step ST4 of the first embodiment for the discrimination criterion at this time.

  If the paper feed time T is 80% or less of the jam detection time Tj, the paper feed operation has shifted with a margin of 20% from the feed detection time tx to the jam detection time Tj. Perform print job completion determination. The end determination of the print job is as described in the first embodiment. If the EOF of the print job is not detected, the process returns to step ST22 and the paper feeding operation (control) is continued.

  In step ST24 described above, the CPU 55 determines whether the paper feed time T has exceeded 80% of the jam detection time Tj, and branches the control. The discrimination criteria at this time are as described in the first embodiment. If the paper feed time T is 80% or less of the jam detection time Tj, the paper feed operation has shifted with a margin of 20% from the feed detection time tx to the jam detection time Tj, so the process proceeds to step ST25. The CPU 55 branches the control based on whether or not the paper feed time T exceeds 50% of the jam detection time Tj. In this case, the criterion is that the paper feed time T = 0.5 · Tj, which is 50% of the jam detection time Tj, is compared with the paper feed time T from the paper feed start time t0 to the feed detection time t1. It is determined whether the paper time T has exceeded 50% of the jam detection time Tj.

  If the paper feed time T does not exceed 50% of the jam detection time Tj, the CPU 55 activates the counter 57a in step ST27 and counts the number N of detections of the paper feed time T that is 50% or less of the jam detection time Tj. To control. The counter 57a measures the detection count N of the paper feed time T that is 50% or less of the jam detection time Tj.

  Thereafter, in step ST28, the CPU 55 branches the control in accordance with whether or not the number N of detection of the paper feed time T that is 50% or less of the jam detection time Tj is equal to or greater than the threshold number Nth = 5. In this case, the determination criterion is that the number N of detections of the paper feed time T equal to or less than 50% of the jam detection time Tj is compared with the threshold number Nth = 5 set by the user, and the detection number N is the threshold number Nth. This is performed by detecting whether the number of times of detection is less than 5 or the number of times of detection N is greater than or equal to the threshold number of times Nth = 5.

  When the number of detections N of the paper feed time T equal to or less than 50% of the jam detection time Tj is less than the threshold number Nth = 5, the process returns to step ST22 to continue the paper feed operation (control). When the number of detections N of the paper feed time T that is 50% or less of the jam detection time Tj is equal to or greater than the threshold number Nth = 5, the CPU 55 decreases the amount of air blown from the front end air 2 in step ST29.

  In step ST30, the CPU 55 measures the paper feed time T1 after the air volume reduction of the front end air 2 (see step ST23). Thereafter, in step ST31, the CPU 55 branches the control based on whether or not the paper feed time T1 after the air volume reduction of the front end air 2 has exceeded 50% of the jam detection time Tj. The discrimination criteria at this time are the same as in step ST24. If the paper feed time T1 after the increase in the air volume of the front end air 2 is 80% or less of the jam detection time Tj, the process returns to step ST22 and the paper feed operation (control) is continued.

  If the paper feed time T1 after the decrease in the air volume of the front end air 2 does not exceed 50% of the jam detection time Tj, the process returns to step ST29 and the blowing air volume of the front end air 2 is decreased. In step ST31, the CPU 55 returns to step ST22 and continues the paper feeding operation (control) when the paper feeding time T1 after the air volume reduction of the front end air 2 exceeds 50% of the jam detection time Tj.

  In step ST25 described above, when the paper feed time T exceeds 50% of the jam detection time Tj, the CPU 55 proceeds to step ST26. In step ST <b> 26, the CPU 55 executes print job end determination. When the EOF of the print job is detected, the paper feed control ends. If the EOF of the print job is not detected, the process returns to step ST22 and the paper feeding operation (control) is continued.

  In step ST24, if the paper feed time T exceeds 80% of the jam detection time Tj, the CPU 55 proceeds to step ST32 shown in FIG. 7, and the CPU 55 activates the counter 57b to detect the jam. The counter 57b is controlled so as to count the number of detections N of the paper feed time T exceeding 80% of the time Tj. The counter 57b measures the detection count N of the paper feed time T that exceeds 80% of the jam detection time Tj. Thereafter, in step ST33, the CPU 55 branches the control in accordance with whether or not the number N of detections of the paper feed time T exceeding 80% of the jam detection time Tj is equal to or greater than the threshold number Nth = 5. Refer to step ST7 of the first embodiment for the discrimination criterion at this time.

  If the number N of detections of the paper feed time T exceeding 80% of the jam detection time Tj is less than the threshold number Nth = 5, the process returns to step ST22 and the paper feed operation (control) is continued. When the number N of detections of the paper feed time T exceeding 80% of the jam detection time Tj is equal to or greater than the threshold number Nth = 5, the CPU 55 increases the amount of blowing air of the front end air 2 in step ST34.

  In step ST35, the CPU 55 measures the paper feed time T1 after the increase in the air volume of the front end air 2 (see step ST23). Thereafter, in step ST36, the CPU 55 branches the control based on whether or not the paper feed time T1 of the front end air 2 has exceeded 80% of the jam detection time Tj. The discrimination criteria at this time are the same as in step ST24. If the paper feed time T1 after the increase in the air volume of the front end air 2 is 80% or less of the jam detection time Tj, the process returns to step ST22 and the paper feed operation (control) is continued.

  If the paper feed time T1 exceeds 80% of the jam detection time Tj, the process returns to step ST34 and the blowing air volume of the front end air 2 is increased. Thereafter, in step ST35, the CPU 55 measures the paper feed time T1 after the increase in the air volume of the front end air 2 (see step ST23). Thereafter, when the paper feed time T1 does not exceed 80% of the jam detection time Tj in step ST36 described above, the CPU 55 returns to step ST22 and continues the paper feed control. Thereby, the blowing air volume of the front end air 2 can be converged to an optimum value.

  As described above, according to the sheet feeding device 100 as the second embodiment, the CPU 55 performs the sheet feeding time T from the sheet feeding start time t0 in the side end air blowing units 20 and 20 to the feeding detection time tx in the feeding detection sensor 12. Is calculated, a change (increase / decrease) in the paper feed time T before and after the increase / decrease in the front end air 2 is detected, and the front end air amount Qf in the front end air blowing section 70 is controlled in response to the detection of the paper feed time T. .

  By controlling the front end air amount Qf, the blowing air amount of the front end air 2 in the front end air blowing unit 70 can be converged to an optimum value. Therefore, it becomes possible to automatically adjust the blowing air volume of the front end air 2 without using manual adjustment. This makes it possible to provide a high-reliability large-capacity paper feeder (PFU) and the like.

  In the above-described embodiment, the case where the amount of blowing air of the front end air 2 in the front end air blowing unit 70 is increased has been described. However, the present invention is not limited to this. Of course, as shown in FIG. 6, when the number N of detections of the paper feed time T exceeding 80% of the jam detection time Tj is less than the threshold number Nth = 5, the front end air in the front end air blowing unit 70 The same effect can be obtained when the blowing air volume 2 is reduced.

  In that case, a change (increase / decrease) in the paper feed time T from the paper feed start time t0 before and after the decrease of the front end air 2 to the delivery detection time tx is detected, and the paper feed time T0 before the front end air 2 decreases is detected. In comparison, when the paper feed time T1 after the decrease of the front end air 2 is increased, the amount of air blown by the front end air 2 in the front end air blowing unit 70 is increased, and when the paper feed time T1 is decreased, the front end air blowing unit. The amount of air blown by the front end air 2 at 70 is reduced.

  Even when the air amount is controlled in this way, according to the sheet feeding device 100, the air is blown up by the side end air blowing units 20 and 20 in the range of 50% to 80% of the jam detection time Tj, and the front end air The sheets P separated by the spray unit 70 can be sucked and transported one by one by the sheet suction transport unit 40.

<Third Embodiment>
Next, a control example of the sheet feeding device 100 as the third embodiment will be described with reference to FIG. According to the control flowchart of the sheet feeding device 100 shown in FIG. 8, the side end air 1a, 1b and the front end air 2 are kept constant, and the suction air 3 is adjusted. In step ST41 shown in FIG. Similar to the first embodiment, the initial setting is executed. In step ST42, the CPU 55 receives the paper feed operation start signal and executes the paper feed operation. The sheet feeding operation start signal is received by the control unit 50 from the image forming apparatus 200 by starting the communication unit.

  In step ST43, the CPU 55 starts measuring the paper feed time T. For example, the CPU 55 starts the timer 56 when the paper feed operation start signal rises. The start time of the timer 56 becomes the paper feed start time t0 in the side end air blowing units 20 and 20. For the paper feed start time t0 and the feed detection time t1, refer to step ST3 in the first embodiment.

  In step ST44, the CPU 55 determines whether the paper feed time T has exceeded 80% of the jam detection time Tj, and branches the control. Refer to step ST4 in the first embodiment for the discrimination criteria at this time. If the paper feed time T is 80% or less of the jam detection time Tj, the paper feed operation has changed with a margin of 20% from the feed detection time tx to the jam detection time Tj. Perform print job completion determination.

  The print job end determination is performed by, for example, receiving a print end flag (EOF) from the image forming apparatus 200 and detecting the EOF. When the EOF of the print job is detected, the paper feed control ends. If the EOF of the print job is not detected, the process returns to step ST42 to continue the paper feeding operation (control).

  If the paper feed time T exceeds 80% of the jam detection time Tj in step ST44 described above, the CPU 55 proceeds to step ST46 and the CPU 55 activates the counter 57b to exceed 80% of the jam detection time Tj. Control is performed so that the number of times N of detection of the paper feed time T is counted. For the operation of the counter 57b, refer to step ST6 in the first embodiment.

  Thereafter, in step ST47, the CPU 55 determines whether or not the number N of detections of the paper feed time T exceeding 80% of the jam detection time Tj is equal to or greater than the threshold number Nth = 5, and branches the control. Refer to step ST7 in the first embodiment for the discrimination criterion at this time. When the number N of detections of the paper feed time T exceeding 80% of the jam detection time Tj is less than the threshold number Nth = 5, the process returns to step ST42 and the paper feed operation (control) is continued. When the number N of detections of the paper feed time T exceeding 80% of the jam detection time Tj is equal to or greater than the threshold number Nth = 5, the CPU 55 increases the air volume of the suction air 3 (see FIG. 2) in step ST48.

  In step ST49, the CPU 55 measures the paper feed time T1 after the increase in the air volume of the suction air 3 (see step ST3). Thereafter, in step ST50, the CPU 55 determines whether or not the paper feed time T1 after the increase in the air volume of the suction air 3 has exceeded 80% of the jam detection time Tj, and branches the control. The discrimination criteria at this time are the same as in step ST44. If the paper feed time T1 after the increase in the air volume of the suction air 3 is 80% or less of the jam detection time Tj, the process returns to step ST42 and the paper feed operation (control) is continued.

  In step ST50, if the feeding time T1 after the increase in the air volume of the suction air 3 exceeds 80% of the jam detection time Tj, the CPU 55 determines in step ST51 that the feeding time T1 after the increase in the air volume of the suction air 3 and its The paper feed time T0 before the increase in the air volume is compared, and the control branches based on the comparison result. When the paper feeding time T1 after the increase in the air volume of the suction air 3 is equal to or shorter than the paper feeding time T0 before the air volume increase (T1 ≦ T0), the flow returns to step ST48 and the air volume of the suction air 3 is increased. When the feeding time T1 after the increase in the air volume of the suction air 3 exceeds the feeding time T0 before the increase in the air volume (T1> T0), the process proceeds to step ST52 and the air volume of the suction air 3 is decreased. Thereby, the air volume of the suction air 3 can be converged to an optimum value.

  Thus, according to the sheet feeding device 100 as the third embodiment, the CPU 55 of the control unit 50 reaches from the sheet feeding start time t0 in the side end air blowing units 20 and 20 to the feeding detection time tx in the feeding detection sensor 12. The paper feed time T is calculated, the paper feed time T before and after the increase or decrease of the suction air 3 of the suction fan 77 in the paper suction conveyance unit 40 is detected, and the paper suction is performed in response to the detection (change or increase) in the paper feed time T. The air volume of the suction air 3 in the transport unit 40 is controlled.

  By controlling the air volume of the suction air 3, the air volume of the suction air 3 in the paper suction conveyance unit 40 can be converged to an optimum value. Accordingly, the air volume of the suction air 3 can be automatically adjusted without manual adjustment. This makes it possible to provide a high-reliability large-capacity paper feeder (PFU) and the like.

  In the above-described embodiment, the case where the air volume of the suction air 3 is increased has been described. However, the present invention is not limited to this. As described in the first embodiment, the sheet suction conveyance is performed in accordance with the comparison result between the detection number N of the paper feed time T exceeding 80% of the jam detection time Tj and the set threshold number Nth = 5. The same effect can be obtained when the air volume of the suction air 3 in the portion 40 is reduced.

  In that case, a change (increase / decrease) in the paper feed time T from the paper feed start time t0 before and after the reduction of the suction air 3 to the delivery detection time tx is detected, and the paper feed time T0 before the suction air 3 is reduced. When the paper feed time T1 after the decrease of the suction air 3 is increased, the air volume of the suction air 3 in the paper suction conveyance unit 40 is increased. Further, when the paper feed time T1 is reduced compared to the paper feed time T0 before the reduction, the air volume of the suction air 3 is reduced.

  Thus, even when the air volume of the suction air 3 is controlled, the sheet P that is floated by the side-end air blowing units 20 and 20 leaving a margin of (100−X)% with respect to the jam detection time Tj. Can be sucked and transported one by one by the sheet suction transport unit 40.

  The present invention is an automatic adjustment function of side air, front end air, and suction air when air is blown to the side edges of a plurality of sheets loaded on a sheet placing table and the uppermost sheet that has floated is sent to the sheet conveyance path. The present invention is very suitable when applied to a large-capacity paper feed unit equipped with

10 Paper Placement Table 11 Adsorption Detection Sensor 12 Delivery Detection Sensor (Paper Detection Unit)
DESCRIPTION OF SYMBOLS 13 Mounting stand raising / lowering drive part 21,71 Main body duct part 22 Sliding duct 23 R-shaped guide part 30 Paper separation conveyance part 31 Paper feed roller 32 Rolling roller 33 Roller drive part 40 Paper adsorption conveyance part 41 Conveyance belt 42 Drive roller 42b Belt Drive unit 43, 44, 45 Guide roller 48, 98 Operation display unit 50 Control unit 51 Oscillator 52 Memory unit 55 CPU
56 timer 57a, 57b counter 58 timing generator 60 blowing port elevating unit 65, 74 blower fan 66 elevating motor 77 suction fan 100 paper feeder 101, 102, 103, 201 paper feeder 200 image forming apparatus

Claims (10)

A first air blower that blows side end air to the side surface of the paper loaded on the paper placing table movable in the vertical direction;
A second air blowing unit that blows front-end air on the front surface of the sheet to separate the uppermost sheet and the next sheet of the sheet mounting table;
A conveying unit that conveys the paper that is levitated by the first blowing unit and separated by the second blowing unit one by one;
A detection unit that detects the sheet conveyed by the conveyance unit at a predetermined position;
Supply from the paper feed start time at which the paper is fed by at least one of the first air blower and the second air blower to the paper detection time at which the paper is detected by the detector. Calculate paper time,
And a control unit that controls an amount of at least one of the side end air and the front end air in accordance with the calculation of the sheet feeding time. The controller is
Measure the number of detections of the paper feed time exceeding a predetermined ratio,
The number of times of detection of the paper feed time exceeding a predetermined ratio is compared with a predetermined threshold number of times set, and the blower unit corresponding to a comparison result between the number of times of detection of the paper feed time and the threshold number of times The sheet feeding device according to claim 1, wherein the blowing air volume of at least one of the side end air and the front end air is increased or decreased. The controller is
When the number of detections of the paper feed time exceeding a predetermined ratio is equal to or greater than a predetermined threshold number of times,
Increasing the blowing air volume of the side end air in the first air blowing part,
Calculate the paper feed time from the paper feed start time after the increase of the side edge air to the paper detection time,
When the paper feeding time after the increase of the side end air is increased compared to the paper feeding time before the increase of the side end air, the amount of blowing air of the side end air in the first air blowing unit is reduced,
If the paper feed time decreases,
The sheet feeding device according to claim 2, wherein the amount of air blown by the side end air in the first air blowing unit is increased. The controller is
When the number of detections of the paper feed time exceeding a predetermined ratio is less than the threshold number of times,
Reducing the blowing air volume of the side end air in the first air blowing section;
Calculate the paper feed time from the paper feed start time after the decrease of the side edge air to the paper detection time,
When the paper feeding time after the side edge air has decreased compared to the paper feeding time before the side edge air has decreased,
Increasing the blowing air volume of the side end air in the first air blowing part,
If the paper feed time decreases,
The sheet feeding device according to claim 2, wherein the amount of air blown by the side end air in the first air blowing unit is reduced. The controller is
When the number of detections of the paper feed time exceeding a predetermined ratio is equal to or greater than the threshold number,
Increasing the amount of air blown by the front end air in the second air blowing part,
Calculate the paper feed time from the paper feed start time after the increase of the front end air to the paper detection time,
When the paper feed time after the increase of the front end air is increased compared to the paper feed time before the increase of the front end air,
Reducing the amount of air blown by the front end air in the second blowing section;
If the paper feed time decreases,
The sheet feeding device according to claim 2, wherein the amount of air blown by the front end air in the second blowing unit is increased. The controller is
When the number of detections of the paper feed time exceeding a predetermined ratio is less than the threshold number of times,
Reducing the amount of air blown by the front end air in the second blowing section;
Calculate the paper feed time from the paper feed start time after the decrease of the front end air to the paper detection time,
When the paper feeding time after the front end air is decreased compared to the paper feeding time before the front end air is decreased,
Increasing the amount of air blown by the front end air in the second air blowing part,
If the paper feed time decreases,
The sheet feeding device according to claim 2, wherein the amount of air blown by the front end air in the second blowing unit is reduced. The transport unit is
Adsorbing the sheets that are levitated by the second air blowing unit one by one with suction air,
The controller is
The sheet feeding device according to claim 1, wherein an air volume of the suction air is controlled corresponding to the calculation of the sheet feeding time. The controller is
Measure the number of detections of the paper feed time exceeding a predetermined ratio,
The number of detections of the paper feed time exceeding a predetermined ratio is compared with a predetermined threshold number of times set, and the conveyance unit corresponds to a comparison result between the number of detections of the paper feed time and the threshold number of times. The sheet feeding device according to claim 7, wherein the air volume of the suction air in the chamber is increased or decreased. The controller is
When the number of detections of the paper feed time exceeding a predetermined ratio is equal to or greater than the threshold number,
Increase the air volume of suction air in the transport section,
Calculate the paper feed time from the paper feed start time after the increase of the suction air to the paper detection time,
When the paper feeding time after the increase in the suction air is increased compared to the paper feeding time before the increase in the suction air,
Reduce the air volume of the suction air in the transport unit,
If the paper feed time decreases,
The sheet feeding device according to claim 8, wherein an air volume of suction air in the transport unit is increased. The controller is
When the number of detections of the paper feed time exceeding a predetermined ratio is less than the threshold number of times,
Reduce the air volume of the suction air in the transport unit,
Calculate the paper feed time from the paper feed start time after the suction air reduction to the paper detection time,
When the paper feeding time after the suction air decreases compared to the paper feeding time before the suction air decreases,
Increase the air volume of suction air in the transport section,
If the paper feed time decreases,
The sheet feeding device according to claim 8, wherein an air volume of suction air in the transport unit is reduced.

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