JP5849800B2 - Paper feeder - Google Patents

Description

  The present invention relates to an air suction belt system in which air is blown to the side edges of a plurality of sheets stacked on a mounting table, the uppermost sheet that has floated is once adsorbed to an adsorption conveyance unit, and then the sheet is fed to a conveyance path The present invention relates to a paper feeding apparatus to which the

  In recent years, in the printing field for commercial use and large-scale enterprises, an image forming system that outputs a large amount of printed matter at high speed by connecting a paper feeding device to an image forming apparatus such as a printer, a copying machine, or a complex machine has been used. Has been. Such a sheet feeding device is required to reliably feed a large number of sheets stacked on the mounting table one by one to the image forming apparatus at a high speed.

  By the way, according to the paper feeder provided with the air suction belt type paper feed tray, it is provided with a mounting table, a spraying unit, and a suction conveying unit, and the floating air is blown from the side surface of the paper on the mounting table to lift the paper. In this structure, the sheet is sucked and conveyed to a suction conveyance unit provided in the sheet.

  According to the paper feeding device described in Patent Document 1, between the suction conveyance unit and the mounting table, the first stop position that stops the blowing air blowing port on the side close to the uppermost sheet on the mounting table; The second stop position for stopping the spray port is set on the side close to the suction conveyance unit. When the sheet is not attracted to the suction conveyance unit, the spray port is maintained at the first stop position. When the sheet is adsorbed by the suction conveyance unit, the sheet is sucked up to the conveyance path by rotating the conveyance belt after raising the spray port to the second stop position above the first stop position. When the sheet is sent from the suction conveyance unit to the conveyance path, the spray port at the second stop position is lowered to the first stop position (see Patent Document 1).

  As described above, in the prior art, when the paper is set, the control mode relating to the air volume according to the paper type / basis weight, the position of the flying air, and the like is automatically set in advance. Regarding the setting of the control mode, the user may check the state of the paper and manually set the air volume, the position of the flying air, and the like. The paper feed conditions once set are retained until the user changes the settings.

  On the other hand, the paper may be curled depending on the use environment, and the behavior such as easiness of floating with respect to the air blown from the side surface greatly changes depending on the curling direction and basis weight. For this reason, even with the same paper type, size, and basis weight, it is necessary to adjust the strength and position of the air to be blown according to the curl state.

JP 2010-184768 A

  The air suction belt type paper feeder according to the conventional example has the following problems.

  i. The control mode related to the position of the spraying part is set in advance, and once the control mode is set, the paper feeding operation is performed in this control mode, so the paper floating and suction operations are unstable during the job. However, it cannot be adjusted until the user changes the setting. As a result, a paper feed failure such as a jam may occur.

  ii. Also, even when the optimal control mode is selected when setting paper, the characteristics of the upper paper and the lower paper may change depending on the usage environment, and the paper feed is unstable. And there is a problem that paper feeding is poor.

  iii. Incidentally, since the purpose of attracting the sheet to the suction conveyance unit in the floating of the sheet found in Patent Document 1, the position of the spraying port of the spraying unit is often set to the first stop position. However, when the paper is curled or thin, it is easy to float, so if the position of the spray port is set to the first stop position, the floating force becomes too large, causing double feed. There is.

  Therefore, the present invention solves the above-described problem, and it is possible to prevent double feeding by switching the control mode with respect to the position of the air blowing port to be levitated, and to deal with by fixing the control mode An object of the present invention is to provide a paper feeding device capable of improving the stability of paper feeding as compared with the above.

  In order to solve the above-described problem, the paper feeding device according to claim 1 is provided on a side surface of the paper stacked on the mounting table, and has a blowing port for blowing up the air for floating the paper upward. A spraying unit having the suction unit, a suction transport unit that is disposed above the paper stacked on the mounting table and sucks and transports the paper that is floated by the spraying unit, and the paper that is sucked by the suction transport unit A suction detection unit for detecting the position, a switching unit for switching the position of the spray port between an uppermost sheet on the mounting table and a lower lower position between the uppermost sheet and the suction conveyance unit, and the suction A control unit that controls the transport unit, the spraying unit, and the switching unit, and a first control mode for sucking and transporting the paper by setting the spraying port at an upper position; The lower position The second control mode is set to switch from the lower position to the upper position in the latter period, and the sheet is sucked and conveyed. The controller detects that the sucking detector is in a predetermined state during the execution of the first control mode. When the suction of the paper is not detected within the time, the spray port is changed from the upper position to the lower position, and when the suction detection unit detects the suction of the paper, the spray port is moved from the lower position to the lower position. In addition to returning to the upper position, when the number of times the sheet suction is detected exceeding the predetermined time exceeds a threshold number, the first control mode is changed to the second control mode.

  According to the paper feeding device of the first aspect, it corresponds to a case where the paper is sucked over a predetermined time due to a sudden event and a case where the paper is sucked over a predetermined time due to a tendency event. The paper feed control can be executed by switching the control mode.

According to a second aspect of the present invention, in the paper feeding device according to the first aspect, the control unit sets the spray port at the lower position and executes the uppermost position on the mounting table during the execution of the second control mode. A preparatory operation for blowing air onto the paper to float the paper is performed, and a standby operation following the preparatory operation, wherein the spray port is moved from the lower position to the upper position during the standby state for sucking and waiting for the paper. It is characterized by switching to a position.

  According to a third aspect of the present invention, in the paper feeding device according to the first aspect, when the suction detection unit detects the suction of the paper during the execution of the second control mode, the control unit sets the spray port to the spray port. It is characterized by switching from a lower position to the upper position.

According to a fourth aspect of the present invention, in the first to third aspects, the sheet feeding device includes a sending detection unit that detects the sheet fed from the suction conveyance unit to the conveyance path, and the control unit is configured to perform the second control mode. During the execution, when the delivery detection unit detects delivery of the paper, the spraying port is switched from the upper position to the lower position.

A sheet feeding device according to a fifth aspect of the present invention is the paper feeding apparatus according to the first to fourth aspects, wherein the control unit includes a counter, and the counter continuously generates an operation of being sucked over the predetermined time. It is characterized by counting the number of times the time is exceeded.

According to a sixth aspect of the present invention, in the first to fifth aspects, the control unit includes a counter, and the counter picks up a predetermined number of paper feeding operations beyond the predetermined time. The control unit counts the number of times the operation is performed , and the control unit starts from the first control mode when the ratio of the number of times to a predetermined number of sheet feeding operations exceeds a certain number of times. It changes to 2nd control mode, It is characterized by the above-mentioned.

According to a seventh aspect of the present invention, in the first to sixth aspects, the sheet feeding device includes an abnormality detection unit that detects an abnormality of the sheet that is levitated and sucked and transported by the spraying unit and the suction transport unit. When the abnormality detection unit detects the conveyance failure of the sheet during the execution of the first control mode, the first control mode is switched to the second control mode when the job is resumed after the jam processing of the sheet. It is characterized by that.

Sheet feeding apparatus according to claim 8, in claim 1 to 7, characterized in that to obtain Bei selection unit which receives a selection of the first control mode or the second control mode from the user.

  According to the paper feeding device of the present invention, the control mode is set in response to the case where the paper is attracted over a predetermined time due to a sudden event and the case where the paper is attracted over a predetermined time due to a tendency event. The paper feed control can be executed by switching. Therefore, if the paper is curled or if paper such as thin paper is likely to rise, the position of the spray outlet can be changed from the lower position to the upper position, so that the floating force of the paper can be weakened and the weight of the paper can be reduced. You can prevent sending.

  Moreover, when the paper is attracted over a predetermined time due to a trending event, it is possible to change to a control mode that strengthens the floating air, so compared with the case where the control mode is fixed and dealt with The stability of paper feeding can be improved, and a highly reliable paper feeding device can be provided.

According to the paper feeding device according to claim 8, since the selection of the first control mode or the second control mode obtain Bei selection unit which receives from the user, or the type of paper, the basis weight, with respect to its size, flying The control mode can be changed freely to increase air. Accordingly, it is possible to improve the stability of paper feed as compared with the case where the control mode is fixed.

1 is a cross-sectional view illustrating an overall configuration example of a sheet feeding device 100 as an embodiment according to the present invention. 3 is a perspective view illustrating a configuration example of a suction conveyance unit of a paper feeding unit 101. FIG. It is a partial sectional view showing an example of the configuration of the suction conveyance unit 40 and its periphery. (A) And (B) is sectional drawing of partial crushing which shows the operation example of a paper floating adsorption conveyance system. It is sectional drawing of partial crushing which shows the example of a structure of the raising / lowering part 30 and its periphery. 3 is a block diagram illustrating a configuration example of a control system of the sheet feeding device 100. FIG. (A) to (E) are time charts showing the state of the paper P during the paper feeding operation and an example of its suction detection. (A)-(I) is a time chart which shows the example of a setting of the position of the blowing port of the floating air at the time of the 1st and 2nd control mode. 6 is a flowchart illustrating a control example (No. 1) of the sheet feeding device. 6 is a flowchart illustrating a control example (No. 2) of the sheet feeding device.

  Hereinafter, a configuration example, an operation example, and a control example of the sheet feeding device according to the embodiment 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.

  A sheet 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 103. In the apparatus main body 103, for example, two sheet feeding units 101 and 102, a control unit 50, and a conveyance path 80 are provided. The sheet feeding device 100 is configured to send the sheets P stacked on the sheet feeding unit 101 or the sheet feeding unit 102 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 mounting table 10, spraying units 20 and 20, an elevating unit 30, and a suction conveyance unit 40. The mounting table 10 is loaded with a plurality of sheets P in the sheet feeding unit 101 and is movable in the vertical direction. The mounting table 10 is attached with a lifting mechanism (not shown) and moves up and down so that the stacked uppermost paper P is maintained at a predetermined position.

  A pair of blowing parts 20 and 20 are provided on both sides (left and right sides) of the mounting table 10, and operate to blow the flying air 1 to the side edges of the paper P. Each of the spraying units 20 and 20 is disposed on the side surface of the paper P stacked on the mounting table 10 with reference to the paper transport direction I (= y) shown in FIG. In the direction substantially orthogonal to the conveyance direction y), the flying air 1 for floating the paper P is blown from both sides (x = IIa, IIb) above the mounting table 10 (up and down direction z orthogonal to xy).

  Each of the spraying parts 20, 20 has a main body duct part 21, a sliding duct 22, an elevating part 30, and the like. The main body duct portion 21 has a rectangular tube shape (a casing), and has a window portion 24 having a predetermined opening area at a predetermined position facing the side surface of the paper P stacked on the mounting table 10. .

  The main body duct portion 21 is combined in a form in which a sliding duct 22 is included, and the sliding duct 22 operates so as to be slidable along the inner wall of the main body duct portion 21. The upper end portion of the sliding duct 22 is provided with an R-shaped (庇) -shaped air blowing guide portion (hereinafter referred to as an R-shaped guide portion 23) having a predetermined overhanging length.

  The R-shaped guide portion 23 is formed, for example, by removing the upper three sides of the rectangular tube-shaped duct member constituting the sliding duct 22 and bending the remaining one side portion inward to approximately 90 °. Good. The R-shaped guide portion 23 is disposed so as to protrude from the window portion 24 of the main body duct portion 21 to the side of the paper P stacked on the mounting table 10, and is formed by the frame portion of the window portion 24 and the R-shaped guide portion 23. A blowing port 25 having a predetermined opening width is defined.

  In this example, in each of the blowing parts 20, 20, the main body duct part 21 and the sliding duct 22 guide the floating air 1 that causes the paper to float to the blowing port 25. The R-shaped guide portion 23 provided on the upper side of the blowing port 25 blows the flying air 1 to each side edge of the paper P as indicated by white arrows IIa and IIb in FIG. As a result, the paper P positioned at the top of the mounting table 10 is separated from the next paper P and floats by the flying air 1 blown to the side edge of the paper P.

  On the back surface of each of the spraying parts 20, 20, an elevating part 30 that constitutes an example of a switching part is provided. In the blowing unit 20, the elevating unit 30 switches the blowing port 25 that defines the blowing position of the flying air 1 in the vertical direction. The elevating part 30 is engaged with the sliding duct 22 and slides in the vertical direction on the sliding duct 22. Thereby, the blowing port 25 demarcated by the frame part of the window part 24 and the R-shaped guide part 23 can be raised / lowered.

  A suction conveyance unit 40 is disposed above the paper P loaded on the mounting table 10. The suction conveyance unit 40 includes a pair of conveyance belts 41 and 41 and a suction fan 77, and the floated paper P is adsorbed to the conveyance belts 41 and 41 by the suction air from the suction fan 77 and is conveyed to the conveyance belt 41. , 41 is sent to the conveyance path 80 (see FIG. 1). The conveyance path 80 includes a plurality of guide members and a plurality of conveyance rollers, and conveys the paper P sent out from the suction conveyance unit 40 to the image forming apparatus 200.

  The image forming apparatus 200 includes an image forming unit 90. For the image forming unit 90, for example, an electrophotographic tandem color printer is used. The image forming unit 90 forms a color toner image based on image data for yellow (Y), magenta (M), cyan (C), and black (BK). The image forming unit 90 includes image forming units that respectively share Y, M, C, and BK color image forming output functions. The image forming unit 90 is configured to apply an image to a photosensitive drum that is uniformly charged by a charging unit for each image forming color. Based on the data, an electrostatic latent image is formed by a laser scanning print head using a polygon mirror or an optical writing unit (LPH: LED Print Head) using an LED array.

  The electrostatic latent image is developed by the developing device for each image forming color. The color toner image formed on the photosensitive drum by performing such charging, exposure and development is superimposed on the intermediate transfer belt, and the superimposed color toner image is transferred onto the sheet by the transfer unit. The paper P is conveyed from the paper supply unit 101 or the like to the transfer unit by the paper supply device 100. The toner image transferred onto the predetermined paper P is fixed by a fixing device. Thereby, a color image based on the image data can be formed on a predetermined sheet.

  Here, with reference to FIG. 3, a configuration example of the suction conveyance unit 40 and its periphery will be described. The suction conveyance unit 40 shown in FIG. 3 includes, in addition to the conveyance belt 41, an adsorption detection sensor 11, a drive motor (not shown), a drive roller 42, guide rollers 43, 44, 45, a suction chamber 46, a lever 47, and a suction fan 77. Have.

  The driving roller 42 and the guide rollers 43, 44, 45 are arranged at predetermined positions above the paper P stacked on the mounting table 10. The driving roller 42 has a shaft portion 42a, and a driving motor (not shown) is engaged with the shaft portion 42a. The conveyor belt 41 is wound around a driving roller 42 and guide rollers 43, 44, 45. As shown in FIG. 2, the conveyor belt 41 has a plurality of holes 41a on the outer peripheral surface. A suction chamber 46 to which a suction fan 77 is connected is provided inside the transport belt 41, and a negative pressure is created by the suction fan 77.

  According to the sheet feeding device 100, the flying air 1 is blown from the blowing port 25 of the blowing unit 20 to the side edge in the vicinity of the upper surface of the paper P stacked on the mounting table 10. In FIG. 3, the floating air 1 blows out from the back of the figure toward the front. The blowing port 25 having the R-shaped guide portion 23 positioned above the paper P is moved up and down by an elevating unit 30 (shown in FIG. 5) as indicated by a white vertical arrow III in FIG.

  The leading end of the paper P that has floated by the spraying units 20 and 20 is adsorbed to the plurality of holes of the transport belt 41 by the negative pressure of the suction chamber 46. The sheet P adsorbed on the conveyance belt 41 advances in the sheet conveyance direction I due to the rotation of the conveyance belt 41, and is removed from the conveyance belt 41 by the negative pressure indicated by the arrow IV in the drawing and the curvature of the guide roller 44. It is separated and sent to the conveyance path 80.

  The suction detection sensor 11 and the lever 47 are provided inside the suction chamber 46. The lever 47 protrudes downward from the region between the pair of transport belts 41 and 41, and is rotatably attached to the shaft portion of the guide roller 45, for example. The lever 47 is engaged in a suspended manner by a suspension member 49 (coil spring or the like) attached to a predetermined position inside the suction chamber 46, and the distance by which the lever 47 protrudes from the lower surface side of the conveyor belts 41 and 41 is increased. It is regulated.

  The suction detection sensor 11 constitutes an example of a suction detection unit, detects the paper P sucked by the suction conveyance unit 40, and outputs a suction detection signal S11 to the control unit 50. For example, when the paper P is attracted to the transport belt 41, the lever 47 is pushed up by the paper P, and the suction detection sensor 11 detects the pushing up of the lever 47.

  A delivery detection sensor 12 that constitutes an example of a delivery detection unit is provided at the entrance of the conveyance path 80, detects the paper P delivered from the suction conveyance unit 40, and outputs a delivery detection signal S12 to the control unit 50.

  Subsequently, an operation example of the sheet floating suction conveyance system will be described with reference to FIGS. In this example, two positions of the spray port 25 in the spray unit 20 are prepared, and the position is switched by a switching mechanism such as a solenoid or a motor.

  P1 shown in FIGS. 4A and 4B is an upper position located at an upper portion near the suction conveyance unit 40 between the uppermost sheet on the mounting table and the suction conveyance unit, and is a driving roller. It is set at a position that hangs down by a predetermined distance a along the vertical direction z from the reference position p0 obtained by extending the shaft portion 42a of 42 in the horizontal direction. Similarly, p2 is a lower position located in the lower part near the uppermost sheet between the uppermost sheet on the mounting table and the suction conveyance unit, and extends in the vertical direction z from the upper position p1. It is set at a position that hangs down by a predetermined distance b (see FIG. 5).

  According to the sheet floating adsorption conveyance system of the sheet feeding device 100, the sheet P stacked on the sheet feeding units 101 and 102 is fed to the image forming apparatus 200 based on the first and second control modes by the control unit 50. It is made to send out one by one.

  Here, in the first control mode, the position of the blowing port 25 is set at the upper position p1, the flying air 1 is blown to the uppermost sheet P on the mounting table 10 to float the sheet P, and the sheet P is sucked. Control that conveys.

  Further, in the second control mode, at the initial stage of the suction conveyance process, the position of the blowing port 25 is set at the lower position p2, and the flying air 1 is blown onto the uppermost sheet P on the mounting table 10 so that the sheet P In the latter period, the position of the blowing port 25 is switched from the lower position p2 to the upper position p1, and the sheet P is sucked and conveyed.

  In this second control mode, as shown in FIG. 4 (B), the blowing port 25 at the lower position p2 is initially shown in FIG. 4 (A) in accordance with the floating of the sheet P located at the uppermost position. As a result, the flying air 1 is blown from the direction of the white arrows IIa and IIb between the paper P and the next paper P to separate the paper P from the next paper P. Like to do.

  That is, the uppermost sheet P that has been lifted by blowing the flying air 1 onto the side edge of the sheet P shown in FIG. 4B is formed by the R-shaped guide portion 23 provided on the upper side of the blowing port 25. The floating of the side portion is restricted, and the central portion of the uppermost sheet P is attracted to the transport belt 41 by the suction action of the suction fan 77 (see FIGS. 2 and 3). As a result, the sheet P and the next sheet P can be adsorbed with good separability.

  Next, an example of the configuration of the elevating unit 30 and its surroundings will be described with reference to FIG. The elevating unit 30 shown in FIG. 5 elevates and lowers the spray port 25 at the opening of the window 24 of the main body duct portion 21 by elevating and lowering the sliding duct 22 with respect to the main body duct portion 21.

  The elevating unit 30 includes, for example, pulleys 31 and 32, a timing belt 33, a plurality of belt clamping units 34 and 34, and an elevating motor 35. A set of pulleys 31 and 32 are rotatably attached to a predetermined position on the back side of the main body duct portion 21 (opposite side of the window portion 24). In addition to the pulleys 31 and 32, a slit portion 26 having a predetermined length is provided on the back side of the main body duct portion 21 in an area between the pulleys 31 and 32. The slit part 26 is opened according to the movable range of the belt clamping part 34.

  A timing belt 33 is wound around the pulleys 31 and 32. One end of a belt clamping portion 34 is attached to and fixed to the timing belt 33. The other end of the belt clamping part 34 has a protruding shape. The protruding portion of the belt clamping portion 34 is attached and fixed to the back side of the sliding duct 22 through the slit portion 26.

  In this example, a lifting / lowering motor 35 is connected to the pulley 32. A stepping motor is used as the motor 35. A blower fan 60 is connected to the main body duct portion 21. The blower fan 60 sends the flying air 1 to the sliding duct 22 through the main body duct portion 21 as indicated by the broken arrow in the figure, and the flying air 1 sent to the sliding duct 22 is sent to the sliding duct 22. The direction is changed by approximately 90 ° at the R-shaped guide portion 23 at the end of the nozzle, and the air is blown out from the blowing port 25 in the direction of the solid arrow in the figure.

  The blowing port 25 is moved up and down by a lifting unit 30 that lifts and lowers the sliding duct 22 as shown by a solid line and a two-dot chain line in the drawing. For example, the timing belt 33 is hung by the pulley 32 being rotated by the motor 35, and the sliding duct 22 is raised and lowered through the belt clamping portion 34 and the slit portion 26 by the timing belt 33 being hung around, The spraying port 25 will move up and down.

  In this example, the upper position p1 and the lower position p2 at which the blowing port 25 is stopped are provided with a reference position corresponding to the reference position p0 on the motor 35 or the timing belt 33, and from the reference position to the upper position p1 and the lower position p2. This is determined by setting the number of pulses for moving the distances a and b. In addition, the technical means which raises / lowers the blowing port 25 is not limited to this example, It is determined in a design stage using a well-known technique. Accordingly, the paper feeding unit 101 operates. However, the paper feeding unit 102 operates in the same manner as the paper feeding unit 101, and thus the 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. 6 includes, for example, an adsorption detection sensor 11, a delivery detection sensor 12, a mounting table elevating drive unit 13, an elevating motor 35, a belt drive unit 42 b, an operation display unit 48, and a control unit. 50, a blower fan 60, a suction fan 77, a paper transport unit 81, and an abnormality detection sensor 82.

  The mounting table elevating drive unit 13 is connected to the control unit 50, and the mounting table elevating drive unit 13 is provided with an elevating motor (not shown), a position detection sensor, and the like. The mounting table elevating drive unit 13 is configured to elevate the mounting table 10 in the vertical direction z based on the mounting 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 60 and an elevating motor 35 are connected to the control unit 50. The blower fan 60 and the raising / lowering motor 35 are provided in the blowing part 20, and the blower fan 60 generates the floating air 1 based on the blower control signal S60, and the main body duct part 21 and the sliding duct 22 shown in FIG. It operates to send floating air 1 to the air.

  The raising / lowering motor 35 is provided in the raising / lowering part 30, rotates based on the raising / lowering control signal S35, drives the pulley 32 shown in FIG. Go up and down.

  A suction fan 77 is connected to the control unit 50 described above. The suction fan 77 sucks the air inside the suction chamber 46 shown in FIG. 3 based on the suction control signal S77, sets the negative pressure inside the suction chamber 46, and sucks the paper P that has floated by the floating air 1 To work.

  In addition to the suction fan 77, a belt driving unit 42b is connected to the control unit 50. The belt drive unit 42b is provided in the suction conveyance unit 40, is connected to the drive roller 42 shown in FIG. 3, and rotates the drive roller 42 shown in FIG. 3 based on the roller control signal S42. In this example, the belt driving unit 42b rotates the conveyance belt 41 wound around the driving roller 42 and the guide rollers 43, 44, and 45 clockwise.

  The suction detection sensor 11 and the delivery detection sensor 12 are connected to the control unit 50. The suction detection sensor 11 detects the paper P sucked by the suction conveyance unit 40 and outputs a suction detection signal S11 to the control unit 50. The delivery detection sensor 12 detects the paper P delivered from the suction conveyance unit 40 to the conveyance path 80 and outputs a delivery detection signal S12 to the control unit 50.

  For example, when the sheet P is adsorbed by the adsorption conveyance unit 40 and sent out to the conveyance path 80 and the rear end of the sheet passes the transmission detection sensor 12, the transmission detection sensor 12 changes from ON to OFF.

  The control unit 50 constitutes a computer system, inputs a suction detection signal S11 for the paper P from the suction detection sensor 11, and controls the spraying unit 20, the lifting unit 30 and the suction conveyance unit 40 based on the suction detection signal S11. The control unit 50 includes, for example, an oscillator 51, a memory unit 52, a central processing unit (hereinafter referred to as a CPU 55), a timer 56, a counter 57, 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 counter 57, 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 for executing the first and second control modes. A control program is read in correspondence with the setting of the first or second control mode.

  For example, a program for executing the first and second control modes is described in the control data D53. For example, during execution of the first control mode, the CPU 55 monitors whether or not the suction conveyance unit 40 has sucked the paper P within a predetermined time. The position 25 is changed from the upper position p1 to the lower position p2. Thereafter, when the suction conveyance unit 40 sucks the paper P, the CPU 55 returns the position of the spray port 25 from the lower position p2 to the upper position p1, and measures the number A of times of the paper P sucked over a predetermined time. This number A is compared with the threshold number B, and when the number A exceeds the threshold number B, the first control mode is changed to the second control mode.

  In this example, when the CPU 55 executes the second control mode, the position of the blowing port 25 is set at the lower position p2, and the flying air 1 is blown onto the uppermost sheet P on the mounting table 10 to thereby cause the sheet P A preliminary operation is performed to float the air and the spraying port 25 is switched from the lower position p2 to the upper position p1 during the suction standby time for sucking and waiting for the paper P following the preliminary operation.

  Further, when the CPU 55 inputs the suction detection information of the paper P from the suction detection sensor 11 when executing the second control mode, and detects the suction of the paper P based on the suction detection information, the blowing port 25 is moved to the lower position. Switching from p2 to the upper position p1.

  Furthermore, when the CPU 55 detects the delivery of the paper P based on the delivery detection signal S12 from the delivery detection sensor 12 during execution of the second control mode, the spray port 25 is moved from the upper position p1 to the lower position p2. Switch to.

  A timer 56 and a counter 57 are connected to the CPU 55. The timer 56 generates a timer signal based on the CLK signal and outputs it to the CPU 55. Based on the CLK signal and the timer signal, the counter 57 measures the number A (count value indicating the frequency) of the paper P in which the operation of being sucked over a predetermined time continuously occurs.

  For example, when the control mode related to the position of the blowing unit 20 set in advance is the first control mode on the side where the flying air 1 is weak, the counter 57 is used until the sheet P is adsorbed by the adsorbing and conveying unit 40. Count the frequency (continuous number of times) that the time (adsorption operation time) exceeds a certain level. Incidentally, the suction operation time exceeds a certain time when there is a high possibility that the floating air 1 is insufficient.

  By measuring the number of times A (frequency) until the paper P is adsorbed to the adsorbing and conveying unit 40, it can be used as a material for judging whether it is a sudden event or a trending event. If it is determined that there is, the stability of the paper feed can be improved by changing the control mode so as to increase the flying air 1.

  In this example, when the number of times A reaches the threshold number of times B, the CPU 55 controls the blowing unit 20 to change the control mode from the first control mode to the second control mode in which the flying air 1 becomes stronger.

  The timing generator 58 generates a mounting table control signal S13, a lift control signal S35, a roller control signal S42, a blow control signal S60, and a suction control signal S77 based on the control data D53 or the control data D54 and the CLK signal. The mounting table control signal S <b> 13 is a signal for controlling the mounting table 10, and is output from the timing generator 58 to the mounting table lifting / lowering drive unit 13.

  The elevation control signal S35 is a signal for controlling the spraying unit 20, and is output from the timing generation unit 58 to the elevation motor 35. The roller control signal S42 is a signal for controlling the suction conveyance unit 40, and is output from the timing generation unit 58 to the belt driving unit 42b.

  The air blowing control signal S60 is a signal for controlling the blowing unit 20, and is output from the timing generating unit 58 to the blowing fan 60. The suction control signal S77 is a signal for controlling the suction conveyance unit 40, and is output from the timing generation unit 58 to the suction fan 77.

  The CPU 55 is connected to an operation display unit 48 that constitutes an example of a selection unit. The operation display unit 48 is operated so as to manually select the first control mode or the second control mode. For example, the user confirms the floating state of the paper P and manually sets the air volume of the floating air 1 and the position of the blowing port 25.

  The paper feed control conditions set at this time include control modes such as the air volume of the floating air 1 blown from the side of the paper, the position of the sliding duct 22, the air volume of the front air blown from the front of the paper, and the position of the front air duct (not shown). It is.

  By the manual selection operation in the first control mode or the second control mode, it is possible to freely set a control mode change that makes the flying air 1 stronger with respect to the type of the paper P, its basis weight, and its size. Accordingly, it is possible to improve sheet feeding stability as compared with the case where the control mode is fixed.

  In addition to the operation display unit 48, a paper transport unit 81 is connected to the control unit 50, and the paper transport unit 81 controls a transport motor (not shown) in the transport path 80 to rotate a transport roller so that the paper P is fed. The sheet feeding unit 101 or 102 is selected by conveying toward the image forming apparatus 200 or driving a conveyance path switching mechanism by controlling a solenoid (not shown).

  In addition to the paper transport unit 81, an abnormality detection sensor 82 that constitutes an example of an abnormality detection unit is connected to the control unit 50. The abnormality detection sensor 82 detects an abnormality of the paper P that is floated and sucked and conveyed by the spraying units 20 and 20 and the suction conveyance unit 40, for example, an abnormality such as the paper P not floating, and generates an abnormality detection signal S82. The abnormality detection signal S82 is output from the abnormality detection sensor 82 to the control unit 50.

  In this example, when the abnormal detection sensor 82 detects a floating suction conveyance abnormality such that the paper P does not float while the CPU 55 is executing the first control mode, the CPU 55 responds to abnormal floating, suction and conveyance of the paper P. When the job is resumed after the jam processing, the control for floating and sucking and conveying the paper P is switched from the first control mode to the second control mode. The abnormality detection sensor 82 is an optical detection sensor that detects the floating position of the paper P, and is activated at the paper feed start time to detect whether the time required for the paper p to float and suck and transport exceeds a predetermined paper feed time. A timer or the like is used.

  According to this control mode switching function, it is possible to change the control mode so that the flying air 1 is strengthened after the job is resumed when the paper P is adsorbed over a predetermined time due to a tendency event. Accordingly, it is possible to improve sheet feeding stability as compared with the case where the control mode is fixed.

  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 an abnormality detection sensor 92 and a CPU 95 in addition to the image forming unit 90. The abnormality detection sensor 92 detects an abnormality of the paper P in the image forming unit 90, a conveyance path (not shown), a fixing unit, and the like, generates an abnormality detection signal S92, and outputs it to the CPU 95. The CPU 95 generates abnormality detection information based on the abnormality detection signal S92.

  On the other hand, 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 communication means such as a communication modem and a communication interface (not shown). For example, abnormality detection information generated in the image forming apparatus 200 is immediately notified to the sheet feeding apparatus 100. In the sheet feeding apparatus 100, for example, when the abnormality detection information is received from the image forming apparatus 200 when the first control mode is executed, the CPU 55 instructs the sheet conveying unit 81 to stop the sheet conveyance.

  In this example, even when a conveyance abnormality is detected in a system other than the sheet floating adsorption conveyance system, the control for sucking and conveying the sheet P from the first control mode to the second is performed when the job is resumed after the jam processing for the conveyance abnormality of the sheet P. You may make it switch to control mode. Further, the operation display unit 98 may be operated to manually select the first control mode or the second control mode.

  Next, an operation example and control example of the sheet feeding device 100 will be described with reference to FIGS. First, with reference to FIGS. 7A to 7E, the state of the paper P during the paper feeding operation and an example of its suction detection will be described. In this example, the paper P sucked by the suction conveyance unit 40 is detected by the suction detection sensor 11, and a suction detection signal S 11 is output to the CPU 55. In this example, the ON state of the suction detection sensor 11 indicates a state where the paper P is attracted to the suction conveyance unit 40, and the state where the suction detection sensor 11 is OFF indicates that the paper P is not attracted to the suction conveyance unit 40. Indicates the state.

  In this example, the paper feeding operation in the paper feeding device 100 includes a preliminary operation, a suction standby operation, a delivery operation, and a transport operation. These operations are scheduled based on the CLK signal. Here, when the sheet suction start time is t0 and these operation switching times are, for example, t3, t5, and t7, the preliminary operation time T0 in the figure is time (t3-t0), and the suction standby time T1 is time. At (t5-t3), the delivery time T2 is set to time (t7-t5), and the transport time T3 is set to time (t8-t7).

  Pattern (1) shown in FIG. 7A is a suction detection state of paper P such as thin paper having a small basis weight and light, and the paper P is immediately blown up and sucked at suction start time t0, and suction detection sensor 11 Becomes ON, and the suction detection signal S11 is raised to a high level. The suction detection signal S11 is maintained at a high level because the suction conveyance unit 40 is sucking the paper P during the suction standby time T1.

  In this example, since the delivery of the paper P from the suction conveyance unit 40 to the conveyance path 80 is completed at the time t6 of the delivery time T2, the suction detection sensor 11 becomes the paper non-detection state and becomes OFF, and the suction detection signal S11 falls from the high level to the low level. The paper P sent out from the suction conveyance unit 40 is conveyed to the image forming apparatus 200 through the conveyance path 80 at the conveyance time T3.

  A pattern (2) shown in FIG. 7B is an adsorption detection state of a paper P such as plain paper having a larger basis weight than the paper P shown in FIG. The suction detection sensor 11 detects the paper P at time t1 and is turned on.

  A pattern (3) shown in FIG. 7C is a suction detection state of the paper P having a larger basis weight than the paper P shown in FIG. The suction detection sensor 11 detects the paper P at time t2 and is turned on.

  Pattern (4) shown in (D) of FIG. 7 is a suction detection state of paper P having a larger basis weight than that of paper P shown in (C) of FIG. The suction detection sensor 11 detects the paper P and turns ON at time t4 in the suction standby time T1 after the preliminary operation time T0 has elapsed. During the suction standby time T1, since the suction transport unit 40 is sucking the paper P, the high level is maintained.

  In the examples of the patterns (2), (3), and (4), as in the case of the pattern (1), the feeding of the paper P to the transport path 80 is completed at the time t6 of the feeding time T2, so that the suction detection sensor No. 11 becomes a sheet non-detection state and is OFF, and the suction detection signal S11 falls from the high level to the low level.

  Pattern (5) shown in (E) of FIG. 7 is a suction detection state of paper P having a larger basis weight than that of paper P shown in (D) of FIG. This is a case where the sheet P does not float and the suction state cannot be detected. Even if the suction detection sensor 11 passes the preliminary operation time T0 and the suction standby time T1, the suction detection signal S11 remains at the low level. . For this reason, a paper feed failure due to a jam occurs.

  As described above, according to the patterns (1) to (4), the timing at which the paper P is attracted to the suction detection sensor 11 is different, but the suction timing of the paper P passes the suction standby time T1. Has been adsorbed. In the pattern (5), the sheet P is not sucked even after the suction standby time T1 after the preliminary operation time T0 has elapsed, and a paper feed failure such as a jam occurs.

  Next, with reference to FIGS. 8A to 8I, an example of setting the position of the blowing port 25 in the first and second control modes will be described. In this example, the position of the blowing port 25 is switched to the upper position or the lower position by the elevating unit 30.

<First control mode>
In the first control mode [standard] shown in FIG. 8A, the position of the spray port 25 is set to the upper position p1 throughout the preliminary operation time T0, the suction standby time T1, the delivery time T2, and the transport time T3. Is done.

  At the time of recovery # 1 in the first control mode shown in FIG. 8B, the position of the spray port 25 is set to the upper position p1 during the preliminary operation time T0, and from the preliminary operation time T0 to the suction standby time T1. The time is switched to the lower position p2 at the switching time t3, and then the setting is returned from the lower position p2 to the upper position p1 at the time τ1 of the suction standby time T1.

  In this control, even if the floating air is blown at the preliminary operation time T0 to try to float the paper P, the paper P does not float and the suction detection sensor 11 remains off. By switching from p1 to the lower position p2, the flying air 1 is blown at a position close to the paper P on the mounting table 10 to perform forced ascent. As a result, the paper P floats at time τ1, and the suction detection sensor 11 changes from OFF to ON.

  A setting example of the position of the blowing port 25 at the time of recovery # 2 in the first control mode shown in FIG. 8C is a forced floating of the paper P having a larger basis weight than the paper P shown in FIG. In the preliminary operation time T0, the position of the spray port 25 is set to the upper position p1, and at the switching time t3 between the preliminary operation time T0 and the suction standby time T1, the position of the spray port 25 is lowered. The position is set to the position p2, and then the setting of the position of the spray port 25 is returned from the lower position p2 to the upper position p1 at the time τ2 of the suction standby time T1.

  In this control, even if the floating air is blown during the preliminary operation time T0 to attempt to float the paper P, the paper P does not float and the position of the spraying port 25 is in the upper position in the state where the suction detection sensor 11 remains off. By switching from p1 to the lower position p2, about twice the spraying period (τ1-t3) of the flying air 1 shown in FIG. 8B at a position close to the paper P on the mounting table 10 During the period (τ2-t3), the levitation air 1 is blown to perform forced levitation. As a result, the paper P floats at time τ2, and the suction detection sensor 11 changes from OFF to ON.

  A setting example of the position of the spray port 25 at the time of recovery # 3 in the first control mode shown in FIG. 8D is a paper P having a larger basis weight than the paper P shown in FIG. Is to forcibly ascend. At the preliminary operation time T0, the position of the blowing port 25 is set to the upper position p1, and at the switching time t3 between the preliminary operation time T0 and the suction standby time T1, the position of the blowing port 25 is switched to the lower position p2. The position of the spray port 25 is returned from the lower position p2 to the upper position p1 at time τ3 of the suction standby time T1.

  In this control, even when the floating of the paper P is attempted by blowing a predetermined floating air during the preliminary operation time T0, the paper P is not lifted, and the position of the blowing port 25 is kept in a state where the suction detection sensor 11 remains off. By switching from the upper position p1 to the lower position p2, the position near the paper P on the mounting table 10 is approximately three times the blowing period (τ1-t3) of the flying air 1 shown in FIG. During the blowing period (τ3-t3), levitation air 1 is blown to perform forced levitation. As a result, the sheet P floats at time τ3, and the suction detection sensor 11 changes from OFF to ON.

  Thus, according to the first control mode, the position of the blowing port 25 is basically at the upper position p1. However, the state of the suction detection sensor 11 is confirmed during the suction standby time T1, and if the suction detection sensor 11 is not ON, the position of the spray port 25 is temporarily changed to the lower position p2. Thereafter, when the suction detection sensor 11 is turned on, the position of the spray port 25 is returned to the upper position p1. By this operation, when the paper P is not sufficiently lifted, the floating force is temporarily strengthened to prevent problems such as paper jam due to non-adsorption of the paper.

<Second control mode>
In the second control mode, there are prepared a control mode for switching the position of the spray opening 25 only in time and a control mode for switching the position of the spray opening 25 by the output of the suction detection sensor 11.

  In the second control mode (T) shown in (E) of FIG. 8, the position of the blowing port 25 is set at the lower position p2 during the transport time T3 and the preliminary operation time T0, and the preliminary operation time T0 and the suction standby time. At the switching time t3 with T1, the position of the blowing port 25 is changed to the upper position p1, and then the position of the blowing port 25 is returned from the upper position p1 to the lower position p2 at time t6 of the delivery time T2.

  According to the second control mode (T), the flying air 1 is blown at a position close to the paper P on the mounting table 10 during the preliminary operation time T0. The suction detection sensor 11 generates a high-level suction detection signal S11 from the time when the suction of the paper P is detected and turned on until the time t6 of the feeding time T2.

  In the second control mode (2-1) shown in FIG. 8 (F), the position of the spray port 25 is set at the lower position p2 during the transport time T3 and the preliminary operation time T0, and the preliminary operation time T0 and the suction time. This is a case where the suction detection sensor 11 detects the suction of the paper P and turns on at the switching time t3 with the standby time T1. When the suction detection sensor 11 is turned on, the position of the spray port 25 is changed to the upper position p1, and then the spray port 25 is returned from the upper position p1 to the lower position p2 at time t6 of the delivery time T2.

  According to the second control mode (2-1), in the same manner as the second control mode shown in FIG. 8E, in the preliminary operation time T0, at a position close to the paper P on the mounting table 10, Since the floating air 1 is blown and the sheet P happens to float at the time t3 when the preliminary operation time T0 ends and is sucked by the suction conveyance unit 40, the same as (D).

  In the second control mode (2-2) shown in FIG. 8G, the position of the spray port 25 is set at the lower position p2 during the transport time T3 and the preliminary operation time T0, and the time τ1 of the suction standby time T1. Then, the blowing port 25 is changed to the upper position p1, and then the blowing port 25 is returned from the upper position p1 to the lower position p2 at time t6 of the delivery time T2.

  According to the second control mode (2-2), in the preliminary operation time T0, even if the flying air is blown at a position close to the paper P on the mounting table 10, the paper P does not rise, and the preliminary operation time T0. In this state, the sheet P is lifted at the time τ1 after the elapse of time and is sucked by the suction conveyance unit 40. When the suction detection sensor 11 detects the suction of the paper P at time τ1 and is turned ON and the high-level suction detection signal S11 rises, the spray port 25 is changed to the upper position p1, and then the time of the delivery time T2 At t6, the spray port 25 is returned from the upper position p1 to the lower position p2.

  In the second control mode (2-3) shown in (H) of FIG. 8, the position of the blowing port 25 is set to the lower position p2 during the transport time T3 and the preliminary operation time T0, and the time τ2 of the suction standby time T1. Then, the blowing port 25 is changed to the upper position p1, and then the blowing port 25 is returned from the upper position p1 to the lower position p2 at time t6 of the delivery time T2.

  The second control mode (2-3) is the same as the second control mode (2-2) shown in FIG. When the suction detection sensor 11 detects the suction of the paper P at time τ2 and is turned ON, and the high level suction detection signal S11 rises, the spray port 25 is changed to the upper position p1, and then the time of the delivery time T2 At t6, the spray port 25 is returned from the upper position p1 to the lower position p2.

  In the second control mode (2-4) shown in (I) of FIG. 8, the spray port 25 is set at the lower position p2 during the transport time T3 and the preliminary operation time T0, and at the time τ3 of the suction standby time T1, The spray port 25 is changed to the upper position p1, and then the spray port 25 is returned from the upper position p1 to the lower position p2 at time t6 of the delivery time T2.

  The second control mode (2-4) is the same as the second control modes (2-2) and (2-3) shown in (G) and (H) of FIG. Even if the flying air is blown at a position close to the paper P on the mounting table 10 at the preliminary operation time T0, the paper P does not rise, and the paper P floats at time τ3 after the preliminary operation time T0 has elapsed. It is in a state of being sucked by the suction conveyance unit 40. When the suction detection sensor 11 detects the suction of the paper P at time τ3 and is turned ON and the high-level suction detection signal S11 rises, the spray port 25 is changed to the upper position p1, and then the time of the delivery time T2 At t6, the spray port 25 is returned from the upper position p1 to the lower position p2.

  As described above, according to the second control mode (T), the position of the spray port 25 is at the lower position p2 during the preliminary operation time T0, and the position of the spray port 25 is changed to the upper position p1 when the suction standby time T1 is reached. It is made like.

  According to the second control modes (2-1) to (2-4), the position of the spray port 25 is at the lower position p2 during the preliminary operation time T0, and the suction detection sensor 11 is turned on after the suction standby time T1. When the suction detection sensor 11 is turned on at the lower position p2, the position of the spray port 25 is changed to the upper position p1.

  According to the second control mode (T), (2-1 to 2-4), the position of the blowing port 25 is returned to the lower position p2 after the delivery detection sensor 12 is turned on and a predetermined time has elapsed, and the next The preliminary operation time T0 in the paper feeding operation of the paper P is started.

  Next, a control example of the air suction belt type paper feeding apparatus 100 will be described with reference to FIGS. 9 and 10. In this control example, the first control mode is selected as the initial setting of the control mode for the position of the spray port 25. In other words, in the sheet feeding device 100, the operation shown as the first control mode (standard) is fundamental.

  Switching control from the first control mode to the second control mode is performed when the first control mode is selected and the frequency at which the spray port 25 is temporarily changed to the lower position p2 becomes a certain frequency or more. I tried to do it. The fixed frequency may be a continuous number or a fixed rate.

  When the suction detection sensor 11 is not turned on at the preliminary operation time T0, the first control mode (standard) is recovered (complemented) at the suction standby time T1. In the recovery # 1 to # 3 in the first control mode, the timing at which the position of the spray port 25 returns from the lower position p2 to the upper position p1 differs depending on the output of the suction detection sensor 11.

  Further, when a jam due to non-adsorption of the paper P occurs during the measurement of the frequency of temporarily changing the position of the blowing port 25 to the lower position p2, the control mode is set to the first when the job is resumed after the jam processing. The control mode is switched to the second control mode.

  When the user sets the paper P in the paper feeding units 101 and 102 and selects a paper feeding condition such as the type, size, and basis weight of the paper P by operating the operation display unit 48 (98), The CPU 55 automatically sets control modes such as the air volume of the floating air 1 and the position of the blowing port 25.

  Under these control conditions, after the paper P is set in the paper feed tray and the paper feed conditions are set, the CPU 55 initializes the first control mode in step ST1 of the flowchart shown in FIG.

  Then, in step ST2, the CPU 55 waits for the rising edge (ON) of the paper feed start signal. For example, the CPU 55 receives the paper feed start signal from the image forming apparatus 200 via the communication unit. When the paper feed start signal is turned ON, the CPU 55 starts a preliminary operation in step ST3.

  At this time, the position of the blowing port 25 is set to the upper position p1 according to the previously set first control mode. Further, the position of the front-end air blowing port is changed from a state in which a front-end air blowing unit (not shown) assists ascent at the position of the front-end air blowing port to a position effective for separating the paper P. The

  In the preliminary operation, the blower fan 60 of the blowing unit 20 is turned on, and air is blown from the blowing port 25 to the side edge of the paper P, and the flying operation of the flying air is finished in a preset preliminary operation time T0. The paper P on the mounting table 10 is lifted upward by the floating air 1 and is sucked by the suction conveyance unit 40.

  When the preliminary operation is completed, the CPU 55 shifts to an adsorption standby operation in step ST4. Since the suction standby time is set in advance to T1, by starting the timer 56, the CPU 55 obtains a timer signal indicating the suction standby time T1.

  Simultaneously with the start of the suction standby operation, the CPU 55 confirms the output of the suction detection sensor 11 in step ST5. When entering the suction standby, the paper P is held in a state of being sucked for a certain time. During this time, when the suction detection sensor 11 is turned on to detect that the paper P is sucked, the floating air 1 is turned off (or the shutter is closed). This prevents a plurality of sheets P from being adsorbed.

  If the suction detection sensor 11 is ON, the process proceeds to step ST6, and the suction operation ends after waiting for the suction standby time T1. In step ST7, the CPU 55 executes paper P delivery control. In the delivery control, the conveyance belt 41 is driven and the paper P is conveyed from the suction conveyance unit 40 to the conveyance path 80.

  After starting the feeding of the paper P, the CPU 55 confirms the output of the sending detection sensor 12 in step ST8. At this time, the sending detection sensor 12 detects that the leading edge of the paper has reached or has passed the trailing edge of the paper, and outputs a sending detection signal S12 to the CPU 55.

  When the delivery detection sensor 12 detects the arrival of the leading edge of the sheet and is turned on, the process proceeds to step ST9, and the timer 56 is started to set the delivery time Tc. The delivery time Tc varies depending on the paper size of the paper P (length in the paper transport direction). When the leading edge of the paper P passes the delivery detection sensor 12, the paper P is transported into the image forming apparatus 200 by the paper transport unit 81. In step ST10, the CPU 55 waits for the delivery time Tc to end and finishes the delivery operation.

  When the preset delivery time Tc has elapsed, the CPU 55 proceeds to the next paper P feeding operation in step ST11. In this example, after a predetermined time has elapsed after the leading edge of the paper is detected by the delivery detection sensor 12, the operation proceeds to the preliminary operation of the next paper P, and the above-described control is repeated until the designated number of sheets are fed. (Basic operation in the standard first control mode).

  If the suction detection sensor 11 is not turned on in step ST5 after the above-described suction standby operation, the process proceeds to step ST12 shown in FIG. 10, the spray port 25 is changed from the upper position p1 to the lower position p2, and the CPU 55 is changed to step ST13. Confirms the output of the adsorption detection sensor 11.

  If the suction detection sensor 11 is turned on before the suction standby time T1 elapses, the process proceeds to step ST14 where the spray port 25 is changed from the lower position p2 to the upper position p1, and then the above-described steps ST6 to ST The paper feeding operation in ST11 is continued. At the same time, in step ST15, the CPU 55 activates the counter 57 and counts the number of times A exceeds the time (A = A + 1).

  In step ST16, the CPU 55 compares the number A of times exceeding the time and the threshold number B to determine A = B. Here, the number of times A is a count value obtained from the counter 57, and is the number of sheets of paper P that are not sucked at the time of suction start and sucked during the suction standby period. The threshold number B is a threshold setting number for the control branch for evaluating the number A. If A ≠ B, the process proceeds to step ST11. When A = B, the process proceeds to step ST17, the first control mode is switched to the second control mode, and the control for sucking and conveying the paper P is executed.

  In step ST18, if the suction detection sensor 11 is not turned on even after the suction standby time T1 has elapsed, the CPU 55 proceeds to step ST19 and executes a jam display operation. When an abnormality such as the paper P not rising is detected, a message content such as “The paper P is not floating” is displayed on the display unit of the operation display unit 48.

  In step ST20, the CPU 55 executes control based on the restart instruction input after the jam processing. The jam processing is executed by the operator. After the jam processing, the operation display unit 48 is operated to input a restart instruction. If there is no restart instruction input, the process returns to step ST19 to continue the jam display operation.

  If there is a restart instruction input in step ST20, the process proceeds to step ST17 to switch the first control mode to the second control mode. Furthermore, returning to step ST11, the CPU 55 continues the second control mode described above. In step ST11, when the CPU 55 completes the designated number of sheets, the sheet feeding control in the second control mode is terminated.

  As described above, according to the paper feeding device 100 as the embodiment, the CPU 55 monitors whether the suction conveyance unit 40 has sucked the paper P within a predetermined time during the first control mode, and performs the predetermined time. If the paper P is not sucked inside, the blowing port 25 is temporarily changed from the upper position p1 to the lower position p2. When the suction conveyance unit 40 sucks the paper P, the CPU 55 returns the spray port 25 from the lower position p2 to the upper position p1 and measures the time-over count A of the paper P sucked over a predetermined time. The CPU 55 compares the time exceeding number A with the control branching threshold number B, and when the time exceeding number A exceeds the threshold number B, the control for sucking and conveying the paper P from the first control mode to the second control is performed. Change to mode.

  By this control, the control mode is fluidly changed in response to the case where the paper P is adsorbed over a predetermined time due to a sudden event and the case where the paper P is adsorbed over a predetermined time due to a tendency event. The paper feed control can be executed by switching. Therefore, when the paper is curled or thin, the blowing port 25 is changed from the lower position p2 to the upper position p1, so that the levitation force can be weakened and double feeding can be prevented.

  In addition, when the paper P is attracted over a predetermined time due to a trending event, it is possible to change the control mode so that the flying air 1 is strengthened. Paper feed stability can be improved. As a result, it is possible to provide a highly reliable sheet feeding device 100 and the like.

  Further, according to the sheet feeding device 100, when the CPU 55 executes the second control mode, at the time when the suction standby time T1 following the preliminary operation is detected, or when the suction of the paper P is detected based on the suction detection signal S11, the spray outlet 25 is switched from the lower position p2 to the upper position p1.

  According to this switching, the floating that is blown onto the next paper P on the mounting table 10 during the suction standby time when the paper P is picked up for a predetermined time due to a tendency event or after the paper is picked up. The air volume of air 1 can be weakened. As a result, double feeding can be prevented. In addition, the sheet feeding stability can be improved as compared with the case where the control mode is fixed.

  Further, according to the paper feeder 100, when the CPU 55 detects the delivery of the paper P based on the delivery detection signal S12 when the second control mode is executed, the position of the spray port 25 is changed from the lower position p2 to the upper position p1. Therefore, even when the paper P is sucked over a predetermined time due to a trending event, the suction and conveyance can be maintained by the flying air 1 based on the second control mode even after the paper is sent out. Accordingly, it is possible to improve the stability of paper feed as compared with the case where the control mode is fixed.

  Further, according to the paper feeding device 100, the counter 57 of the control unit 50 measures the time A overtime A of the paper P in which the operation of being sucked over a predetermined time continuously occurs. The sheet feeding control can be executed by switching the control mode in a fluid manner in response to a case where the sheet P is sucked over a predetermined time due to an unforeseen event and a case where the sheet P is sucked over a predetermined time due to a tendency event. become.

  In the above-described embodiment, the case where the counter 57 measures the number of times A of paper P exceeds the time has been described, but the present invention is not limited to this. For example, the above-described counter 57 is used to count the rate of occurrence of an operation that is attracted over a predetermined time with respect to a predetermined number of sheet feeding operations including a paper feeding operation that is attracted within a predetermined time. It may be. Even when the counter 57 is used in this way, when the paper P is sucked over a predetermined time due to a sudden event, or when the paper P is sucked over a predetermined time due to a tendency event The sheet feeding control can be executed by switching the control mode in a fluid manner.

10 Mounting table 11 Adsorption detection sensor (adsorption detection unit)
12 Sending detection sensor (sending detection unit)
DESCRIPTION OF SYMBOLS 13 Mounting stand raising / lowering drive part 21 Main body duct part 22 Sliding duct 23 R-shaped guide part 24 Window part 25 Spraying opening 26 Slit part 30 Lifting part 31, 32 Pulley 33 Timing belt 34 Belt clamping part 35 Lifting motor 40 Adsorption conveyance Unit 41 Conveying belt 42 Driving roller 42b Belt driving unit 43, 44, 45 Guide roller 47 Lever 48, 98 Operation display unit 49 Suspension member 51 Oscillator 52 Memory unit 55 CPU
56 timer 57 counter 58 timing generator 60 blower fan 70, 77 suction fan 80 transport path 81 paper transport unit 82, 92 abnormality detection sensor (abnormality detection unit)
DESCRIPTION OF SYMBOLS 90 Image forming part 100 Paper feeding apparatus 101,102 Paper feeding part 200 Image forming apparatus

Claims (8)

A spraying unit that is disposed on a side surface of the paper stacked on the mounting table and has a spraying port for blowing up the floating air for floating the paper above;
A suction transport unit that is disposed above the paper stacked on the mounting table and sucks and transports the paper that is floated by the spraying unit;
A suction detection unit that detects the paper sucked by the suction conveyance unit;
A switching unit that switches the position of the spraying port between the uppermost sheet on the mounting table and the lower suction position between the uppermost sheet and the suction conveyance unit;
A controller that controls the suction conveyance unit, the spraying unit, and the switching unit;
A first control mode in which the blowing port is set to the upper position and the sheet is sucked and conveyed, and in the initial stage of the sucking and conveying step, the blowing port is set to the lower position, and in the latter period, the lower position is changed from the lower position to the upper position. Switching to provide a second control mode for sucking and conveying the paper;
If the suction detection unit does not detect the suction of the paper within a predetermined time during the execution of the first control mode, the control unit changes the spray port from the upper position to the lower position, and When the detection unit detects the suction of the paper, the spraying port is returned from the lower position to the upper position, and when the number of times the paper suction is detected exceeding the predetermined time exceeds a threshold number, A paper feeding device that changes from the first control mode to the second control mode. While the second control mode is being executed, the control unit performs a preliminary operation of setting the blowing port at the lower position and blowing air on the uppermost sheet on the mounting table to float the sheet. ,
2. The sheet feeding device according to claim 1, wherein the spraying port is switched from the lower position to the upper position during the standby operation following the preliminary operation and waiting for the sheet to be sucked. . The control unit switches the spray port from the lower position to the upper position when the suction detection unit detects suction of the paper during execution of the second control mode. Or the sheet feeding device described in 2 . A delivery detection unit that detects the sheet sent from the suction conveyance unit to the conveyance path;
The control unit switches the spray port from the upper position to the lower position when the feeding detection unit detects the feeding of the paper during the execution of the second control mode. one of the sheet feeding apparatus according to 1-3. The control unit has a counter,
The counter is one of the sheet feeding apparatus according to claim 1, wherein counting the number of times exceeds the time of the paper operation to be adsorbed beyond said predetermined time is generated continuously. The control unit has a counter,
The counter counts the number of times that an operation to be sucked over the predetermined time occurs for a predetermined number of sheet feeding operations ,
The control unit is configured to change from the first control mode to the second control mode when the ratio of the number of times for a predetermined number of sheet feeding operations exceeds a certain number of times. The sheet feeding device according to any one of claims 1 to 5. An abnormality detection unit that detects an abnormality of the paper that is levitated and sucked and transported by the spraying unit and the suction transport unit;
When the abnormality detection unit detects a conveyance error of the paper during execution of the first control mode, the control unit starts from the first control mode when the job is resumed after the paper jam processing. one of the sheet feeding apparatus according to any one of claims 1 to 6, characterized in that switching to the control mode. One of the sheet feeding apparatus according to claim 1-7, characterized in that to obtain Bei said first control mode or selecting unit for accepting selection of the second control mode from the user.

Images