JP2016084232A - Sheet feeder and image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet feeder and an image formation device that can reduce occurrence of a defect in feeding a sheet without reference to the kind of sheets to be fed.SOLUTION: Air blowing amounts of floating means 30a and separating means 30b are varied to find proper air blowing amounts of the floating means 30a and separating means 30b at which the number of times of conveyance in which a sheet flaps is the largest. Then a CPU 211 after finding the proper air blowing amounts controls the floating means 30a and separating means 30b so that the air blowing amounts reach the proper air blowing amount.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a sheet feeding apparatus and an image forming apparatus, and more particularly to a sheet feeding and separating sheet by blowing air onto the sheet.

  2. Description of the Related Art Conventionally, an image forming apparatus such as a printer or a copying machine includes a sheet feeding device that feeds sheets one by one from a sheet storage unit in which a plurality of sheets are stored. As such a sheet feeding device, air is blown to the end of the sheet bundle stored in the sheet storage unit to float a plurality of sheets, and only one sheet is placed on the suction conveyance belt disposed above. There is an air feeding type that sucks and feeds (see Patent Document 1).

  Here, a conventional sheet feeding apparatus of an air feeding method is provided at an upper part of a storage for supporting and storing a sheet on a tray, and a suction conveyance unit that sucks and conveys the sheet, and a sheet that is stored An air blowing part is provided for floating the upper part and separating one by one. The suction conveyance unit includes an adsorption conveyance belt, an adsorption fan that generates a negative pressure for adsorbing the sheet to the adsorption conveyance belt, and a suction hole formed in the adsorption conveyance belt. A suction duct for sucking air is provided. Further, the suction conveyance unit is provided with a suction shutter or the like disposed between the suction fan and the suction duct in order to turn ON / OFF the suction operation.

  In addition, the air blowing section is provided with a whirling nozzle and a separating nozzle for blowing air onto the upper part of the stored sheet bundle, and each nozzle is configured so that air is sent from the separating fan via a separating duct. Has been. Then, the air sucked by the separation fan is blown toward the sheet by the firing nozzle, and several sheets of the upper part of the sheet bundle supported on the tray are floated. Further, the air sucked by the separation fan is blown by the separation nozzle toward the downstream end portion of the plurality of sheets that have floated in the sheet feeding direction. As a result, the uppermost sheet of the plurality of sheets that have floated is separated from the second and lower sheets from the top and is sucked onto the suction conveyance belt.

JP-A-7-196187

  By the way, in such an air feeding type sheet feeding apparatus, when the amount of air to be blown is small, the second sheet Sb from the top is removed from the uppermost sheet Sa as shown in FIG. The sheet cannot be separated, and double feeding of sheets occurs. On the other hand, if the amount of air to be blown is too large, as shown in FIG. 9B, the second sheet Sb and the third and subsequent sheets Sc rise too high. In this case, the second sheet Sb comes into contact with the uppermost sheet Sa, and the sliding resistance between the sheets increases, so that double feeding of the sheets occurs. As described above, when the amount of air blown to separate the sheets is small, or when the amount of air is too large, double feeding of the sheets occurs.

  For this reason, in order to feed a sheet without generating double feeding, it is necessary to appropriately set the air volume of air to be blown. However, since the appropriate air flow rate varies depending on the sheet size, basis weight, etc., in order to float and separate various sheets without generating double feed, the sheet size and basis weight are required. It is necessary to change the amount of air blown according to the above. For this reason, for example, there is a conventional one in which the operator can separately adjust the air volume of the blowing air and the separation air according to the situation. However, when feeding a sheet that has not been set, it is difficult to optimally adjust the air volume, and thus feeding failure such as double feeding may occur.

  Accordingly, the present invention has been made in view of such a current situation, and provides a sheet feeding apparatus and an image forming apparatus that can reduce the occurrence of sheet feeding failure regardless of the type of sheet to be fed. It is intended to provide.

  In the sheet feeding device, the present invention provides a sheet support unit that can move up and down to support a sheet bundle, and air is blown to a side surface of the sheet bundle that is supported by the sheet support unit to form a plurality of sheets at the top of the sheet bundle. Air blowing means including a floating means for floating and air blowing means for separating the uppermost sheet of the plurality of sheets by blowing air to the side surfaces of the plurality of sheets that have floated, and the separated uppermost sheet by air In order to detect the occurrence of flapping in the floating direction of the floated sheet due to the air blown from the floating means and the separating means when the uppermost sheet is conveyed by the suction conveyance means and the suction conveyance means that sucks and conveys And a counting means for counting the number of times the detection means detects the occurrence of sheet fluttering when a predetermined number of sheets are conveyed. The sheet conveying operation for conveying a predetermined number of sheets in a state where the air blowing amounts of the floating means and the separating means are changed is performed a predetermined number of times, and the detecting means flutters the sheet based on the counting information from the counting means. After determining the appropriate air blowing amount of the levitation means and the separating means that have detected the occurrence of the occurrence of the occurrence, and determining the appropriate air blowing amount, the air blowing amount becomes the appropriate air blowing amount. And a control means for controlling the levitation means and the separation means.

  As in the present invention, by controlling the levitation means and the separation means so that the air blowing amount becomes the appropriate air blowing amount at which the number of conveyances when the occurrence of the flapping of the sheet is detected becomes the maximum, the type of the sheet to be fed Regardless, the occurrence of sheet feeding defects can be reduced.

1 is a diagram illustrating a schematic configuration of a printer that is an example of an image forming apparatus including a sheet feeding device according to an embodiment of the present invention. The figure which shows the structure of the said sheet feeding apparatus. The control block diagram of the said sheet feeding apparatus. The figure showing the flapping state of the second and subsequent sheets when the uppermost sheet of the sheet feeding apparatus is adsorbed. The figure showing the amount of movement of the up-and-down direction when the above-mentioned 2nd sheet and subsequent sheets flutter. (A) is a figure showing the search table at the time of calculating | requiring optimal air volume, (b) is the figure which put together the fluttering ratio with respect to each setting based on the search table of (a). The flowchart explaining the control which sets the air volume of the isolation | separation air of the said sheet | seat feeding apparatus, and blowing air. 7 is a flowchart illustrating a subroutine for obtaining an appropriate air volume at the time of sheet feeding by the sheet feeding apparatus. In the conventional sheet feeding apparatus, (a) is a diagram for explaining double feeding of sheets that occurs when the amount of air to be blown is small, and (b) is a double feeding of sheets that occurs when the amount of air to be blown is too large. FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram illustrating a schematic configuration of a printer which is an example of an image forming apparatus including a sheet feeding device according to an embodiment of the present invention. As shown in FIG. 1, a printer 100 is provided with a printer main body 101 and an image for reading a document D placed on a platen glass 120 a serving as a document placement table by an automatic document feeder 120. A reading unit 130 is provided. The printer main body 101 includes an image forming unit 102 and a sheet feeding device 103 that feeds the sheet S to the image forming unit 102.

  Here, the image forming unit 102 is provided with a photosensitive drum 112, a developing unit 113, a laser scanner unit 111, a transfer unit 118 composed of the photosensitive drum 112 and a transfer charger, a fixing unit 114, and the like. . Further, the sheet feeding device 103 accommodates a sheet S such as an OHT, and a plurality of sheet storage units 11 that are detachable from the printer main body 101, and a suction conveyance belt 21 that sends out the sheets S stored in the sheet storage unit 11 and the like. I have. The printer main body 101 includes an image formation control unit 203 that controls the image forming operation of the printer main body 101 and the sheet feeding operation of the sheet feeding apparatus 103.

  Next, an image forming operation of the printer 100 having such a configuration will be described. When an image reading signal is output from the image formation control unit 203 provided in the printer main body 101 to the image reading unit 130, the image reading unit 130 reads an image of the document D. Thereafter, a laser beam corresponding to the electric signal is emitted from the laser scanner unit 111 onto the photosensitive drum 112. At this time, the photosensitive drum 112 is charged in advance, and an electrostatic latent image is formed by irradiation with light. Then, the electrostatic latent image is developed by the developing device 113, whereby toner is formed on the photosensitive drum. An image is formed.

  On the other hand, when a paper feed signal is output from the image forming control unit 203 to the sheet feeding device 103, the sheet S stored in the sheet storage unit 11 is fed. Thereafter, the fed sheet S is sent to the transfer unit 118 in synchronization with the toner image on the photosensitive drum by the registration roller 117. Next, the toner image is transferred to the sheet sent to the transfer unit 118 in this way, and then conveyed to the fixing unit 114. Thereafter, the unfixed transfer image is permanently fixed on the sheet S by being heated and pressed by the fixing unit 114. Then, the sheet on which the image is fixed in this manner is discharged from the printer main body 101 to the discharge tray 119 by the discharge roller 116.

  FIG. 2 is a diagram illustrating a configuration of the sheet feeding apparatus 103. The sheet storage unit 11 includes a tray 12 that is a sheet supporting unit that supports the sheet S and can be moved up and down, a rear end regulating plate 13 that regulates the position of the rear end that is the upstream end of the sheet S in the sheet feeding direction, and the sheet And a tip regulating plate 17 that regulates the position of the tip that is the downstream end in the feeding direction. The sheet storage unit 11 includes a side end regulating plate 14 that regulates the position of the sheet S in the width direction orthogonal to the sheet feeding direction. The rear end restricting plate 13 and the side end restricting plate 14 which are restricting portions that restrict the movement of the sheets stacked and supported on the tray 12 are configured so that the positions can be arbitrarily changed according to the size of the stored sheets. Yes.

  The sheet storage unit 11 can be pulled out from the printer main body 101, and when the sheet storage unit 11 is pulled out from the printer main body 101, the tray 12 is lowered to a predetermined position to perform replenishment or replacement of sheets. Can do. The tray 12 is moved up and down by a lifting mechanism (not shown) driven by a tray lifting motor M11 such as a stepping motor or a DC servo motor shown in FIG.

  Further, an air feeding type sheet feeding unit (hereinafter referred to as an air feeding unit) 150 for separating and feeding the sheets one by one is disposed on the upper portion of the sheet storage unit 11. The air sheet feeding unit 150 floats and sucks the suction conveyance unit (suction feeding unit) 19 that sucks and conveys the sheets S stacked on the tray 12 and the upper portion of the sheet bundle SA on the tray. And an air blowing part 30 for separating the sheets one by one.

  Here, the suction conveyance unit 19 serving as a suction conveyance unit is stretched around the belt driving roller 41 and sucks the sheet S and feeds the sheet S in the right direction in the drawing, and the suction conveyance belt 21. An adsorption fan 38 that generates a negative pressure to be adsorbed on the substrate is provided. Further, the suction duct 51 is provided inside the suction conveyance belt 21 and sucks air through a suction hole (not shown) formed in the suction conveyance belt 21. Further, the suction shutter 37 is provided between the suction fan 38 and the suction duct 51 and turns ON / OFF the suction operation of the suction conveyance belt 21. In the present embodiment, a plurality of suction conveyance belts 21 are arranged with a predetermined interval in the width direction.

  The air blowing unit 30 serving as an air blowing unit includes a floating unit 30a that blows air onto the upper side surface of the sheet bundle to float a plurality of sheets. The air blowing unit 30 includes separation means 30b that blows air onto the side surfaces of the plurality of sheets that have floated to separate the uppermost sheet of the plurality of sheets from the sheet positioned below the uppermost sheet. ing.

  The levitation means 30 a includes a firing air duct 32, a firing air nozzle 33 provided at the upper end of the firing air duct 32, and a firing air fan 36 that is a first fan provided at the lower portion of the firing air duct 32. Then, air is sucked by the blown air fan 36 and blown from the blown air nozzle 33 to the upper side surface of the sheet bundle. The separating means 30 b includes a separation air duct 35, a separation air nozzle 34 provided at the upper end of the separation air duct 35, and a separation air fan 31 that is a second fan provided at the lower part of the separation air duct 35. Then, air is sucked by the separation air fan 31 and blown to the side surfaces of the plurality of sheets that have floated from the separation air nozzle 34.

  FIG. 3 is a control block diagram of the sheet feeding apparatus 103 according to the present embodiment. As shown in FIG. 3, the image forming control unit 203 is connected to a control unit 201 that is a control unit that controls the air feeding operation of the air feeding unit 150. The control unit 201 includes a CPU 211, a ROM 213 that stores a sequence necessary for control, a RAM 212 that holds setting values necessary for control, and a counter 214 that is a counting unit.

  The CPU 211 is connected to a tray lifting motor M11 that lifts and lowers the tray 12 via a driver 231, a belt roller motor M12 that drives the suction conveyance belt 21, and a drawing roller motor M13 that drives a drawing roller described later. . The CPU 211 is connected to an adsorption fan motor M14 for driving the adsorption fan 38, a separation fan motor M15 for driving the separation air fan 36, and a separation fan motor M16 for driving the separation air fan 31. Further, the CPU 211 is connected to a sheet flutter detection unit 202 for detecting sheet flutter described later. In the present exemplary embodiment, the image forming control unit 203 controls the sheet feeding device 103 via the control unit 201, but the sheet feeding device 103 may be directly controlled.

  Next, the sheet feeding operation control of the sheet feeding device 103 (air feeding unit 150) by the control unit 201 will be described. First, when the user pulls out the sheet storage unit 11 to set the sheet S on the tray, and then stores the sheet storage unit 11, the control unit 201 drives the tray lifting motor M11 to raise the tray 12. After that, when the distance between the stacked and supported sheets and the suction conveyance belt 21 reaches a position where the distance can be fed, the control unit 201 stops driving the tray lifting / lowering motor M11 and stops the tray 12. Thereafter, a sheet feeding signal for starting feeding from the image forming control unit 203 is prepared.

  Next, when a sheet feeding signal is input, the control unit 201 drives the suction fan motor M14 to rotate the suction fan 38 and discharges air in the direction of arrow H in FIG. At this time, the suction shutter 37 is closed. When the sheet feeding signal is input, the control unit 201 drives the rolling fan motor M15 and the separation fan motor M16 to rotate the rolling air fan 36 and the separation air fan 31, and the arrows as shown in FIG. Inhale air in direction C.

  Then, the air sucked in the direction of arrow C by the blown air fan 36 passes through the blown air duct 32 and is blown out in the direction of arrow D by the blown air nozzle 33, and among the upper part of the sheet bundle SA stacked on the tray 12. Raise multiple sheets. Further, the air sucked in the direction of arrow C by the separation air fan 31 passes through the separation air duct 35 and is blown out in the direction of arrow E by the separation air nozzle 34, and the uppermost sheet among the plurality of sheets floated by the blown air nozzle 33. Separate Sa from the lower sheet.

  Next, when a predetermined time elapses after the sheet feeding signal is detected and the upper sheet is stabilized, the control unit 201 drives a solenoid (not shown) to rotate the suction shutter 37 in the direction of arrow G. . As a result, air is sucked from the suction holes provided in the suction conveyance belt 21 and a suction force is generated. Only the uppermost sheet Sa is adsorbed to the adsorption conveyance belt 21 by the adsorption force and the separation air from the separation air nozzle 34.

  Next, the control unit 201 drives the belt roller motor M12 to rotate the belt driving roller 41 in the arrow J direction. As a result, the uppermost sheet Sa is conveyed while being adsorbed by the adsorbing and conveying belt 21, and thereafter is sent toward the image forming unit by the pulling roller pair 42.

  Incidentally, in the present embodiment, the control unit 201 shown in FIG. 3 independently controls the rotational speeds of the separation fan motor M15 and the separation fan motor M16, thereby independently controlling the air volumes of the separation air and the separation air. It can be adjusted. The fan motors M15 and M16 are PWM-controlled. For example, when the fan motor M15 is driven at a voltage of 24 V and PWM control of 100%, a 200 Hz pulse signal is output as an output signal indicating the rotation speed. ing.

  Here, in the present embodiment, the setting of the air volume of separation air and blowing air, which are control conditions for separation conveyance, is performed based on “the degree of sheet curl”. Note that “the degree of sheet curling” refers to the downstream end in the sheet feeding direction of the second sheet Sb next to the topmost sheet Sa and the plurality of sheets Sc thereafter in the floating sheet. Judgment is made based on the presence or absence of movement in the vertical direction indicated by the arrow F (the presence or absence of flapping).

  Here, when the second sheet Sb is separated from the uppermost sheet Sa and the second sheet Sb and the subsequent sheets Sc are not over-floating, the second and subsequent sheets Sb, Sc is blown with air in a state where it can move up and down without receiving restraint force. In this case, when the uppermost sheet Sa is adsorbed, the second and subsequent sheets Sb and Sc flutter in the F direction.

  For this reason, the higher the ratio of the number of times of fluttering when the uppermost sheet Sa of the second and subsequent sheets Sb, Sc is fed with respect to the preset total number of feeding times, the more It can be determined that the sheet is being rolled with an appropriate air volume. That is, when a predetermined number of sheets are conveyed, the fluttering state is determined every time one sheet is fed, and the second and subsequent sheets flutter at each feeding with respect to the preset total number of feedings. It can be determined that the greater the number of conveyances that have been in the state, the better the curlability.

  Therefore, in the present embodiment, the sheet fluttering detection unit 202 which is a detecting means for detecting whether fluttering of the second and subsequent sheets Sb and Sc has occurred is replaced with a high-speed camera as shown in FIG. 222 and an image processing unit 221. Then, the high-speed camera 222 is installed in the photographing area 151 shown in FIG. 4, and the high-speed camera 222 photographs the flapping state of the sheet from the side surface on the downstream side in the sheet feeding direction of the sheet being fed. Since the interior of the storage is dark, a light source (not shown) is also arranged in the storage.

  Then, at the time of sheet feeding, the flickering of the second and subsequent sheets Sb and Sc is photographed as a moving image in the photographing area 151. Thereafter, the moving image information, which is image information captured by the high-speed camera 222, is input to the image processing unit 221 and processed, and the processed moving image information is output to the CPU 211 that determines the degree of beating. In the CPU 211, the moving image information is analyzed to determine the “degree of sheet curl”, and the movement amount of the second and subsequent sheets Sb and Sc is calculated. At this time, the time for determining whether or not the second and subsequent sheets are fluttered is from the time when the uppermost sheet Sa is adsorbed to the adsorbing and conveying belt 21 to the end of feeding.

  Each time the CPU 211 feeds the uppermost sheet Sa, the second and subsequent sheets Sb and Sc fluttered as indicated by a broken line shown in FIG. 5A, for example, or a solid line shown in FIG. Judge whether it is fluttering. When the second and subsequent sheets Sb and Sc flutter as shown in FIG. 5A, the count value of the counter 214 is set to +1. Then, the ratio of fluttering of the second and subsequent sheets to the total number of sheet feeding is calculated from the count value of the counter 214, and recorded in the RAM 212 shown in FIG. Here, the greater the total number of feeds, the higher the reliability of the fluttering ratio.

  By the way, the occurrence of such flapping of the second and subsequent sheets varies depending on the air volume of the separation air and the burning air, that is, the amount of air blown. Thus, in the present embodiment, the CPU 211 controls the separation air and blowing air volume (air blowing amount) and the rotation speed of the blowing air fan 36 and separation air fan 31 to flutter the second and subsequent sheets. Set to an appropriate air volume that maximizes the number of occurrences.

  Next, a method for setting the air volume of such separated air and fired air will be described. In the present embodiment, the PWM setting values of the air fan 36 and the separated air fan 31 are sequentially changed with respect to the initial value stored in advance in the RAM 212 in accordance with the search table as shown in FIG. . Then, the fluttering ratio when the whirling air fan 36 and the separation air fan 31 are driven is calculated based on the changed PWM setting values of the whispering air fan 36 and the separation air fan 31, and the calculated fluttering ratio is shown in FIG. The data is recorded in the RAM 212.

  Then, the CPU 211 sets, based on the search table, the setting value having the highest fluttering ratio among the fluttering ratios of the setting values after the search for performing the sheet conveying operation for conveying the predetermined number of sheets a predetermined number of times is completed. Is registered in the RAM 212. For example, in FIG. 6B, when the air volume is set to 9, the fluttering ratio is 100%, that is, when the sheets are fed, the second and subsequent sheets always flutter. Is adopted. From the next time, when the sheet is fed, the registered condition, that is, the air volume setting of 9, is selected, so that air is blown onto the sheet with an appropriate air blowing amount.

  Next, the control for setting the air volume of the separation air and the burning air will be described with reference to the flowchart shown in FIG. When the CPU 211 first feeds the sheet, the CPU 211 determines whether the sheet has a set air volume, that is, whether the sheet is a registered sheet (S101). If the sheet is a registered sheet (Y in S101), the registered sheet feeding condition is selected (S107), and the sheet feeding operation is performed by, for example, the air volume setting of 9 in FIG. 6B. Is started (S109).

  If the sheet is not an unregistered sheet, that is, a sheet with the air volume set (N in S101), the process shifts to the optimum air volume adjustment mode (S103), and the optimum air volume adjustment is performed. Here, when the mode shifts to the optimum air volume adjustment mode, the CPU 211 searches for the optimum air volume (appropriate air volume) based on the search table shown in FIG. In step S201, a moving image of the sheet being fed is photographed. Then, the captured moving image is output to the image processing unit 221, and the image processing unit 221 analyzes the flapping of the second and subsequent sheets (S203). Thereafter, based on the count information from the counter 214, the CPU 211 calculates the ratio of the number of feeding times of the second and subsequent sheets with respect to the total number of sheet feedings, and records it in the RAM 212 (S205).

  Next, until the search is completed (N in S207), the search for the optimum air volume based on the search table is sequentially performed. That is, the rotational speeds of the separated air and the air fan are individually controlled to change the air volume (S209). When the search is completed (Y in S207), the setting value with the highest flapping ratio is obtained and registered in the RAM 212 (S211). As a result, the optimum air volume adjustment mode for the unregistered sheet ends (S213).

  When the optimum air volume adjustment mode ends in this way, the operator additionally registers sheet information (brand, size, basis weight, surface property, etc.) in the obtained optimum air volume setting data (S105), and feeds the sheet. Then, the feeding condition of the registered sheet is selected (S107). Thereby, when feeding a sheet, air is blown onto the sheet with a registered sheet feeding condition, that is, with an appropriate air volume having the highest flapping ratio. Thereafter, the sheet feeding operation is started (S109). At this time, since air is blown onto the sheet with an appropriate air volume, the floated sheet surely flutters.

  As described above, in the present embodiment, the air blowing amount of the floating means 30a and the separating means 30b is changed, and the appropriate air of the floating means 30a and the separating means 30b where the number of sheet flapping occurs is maximized. The amount of spraying is calculated. And after calculating | requiring the appropriate air spraying amount, it is made to control the floating means 30a and the isolation | separation means 30b so that an air spraying amount may become an appropriate air spraying amount. As a result, the floated sheet is surely fluttered and the curling property is improved. As a result, the occurrence of sheet feeding defects can be reduced.

  In the present embodiment, the “sheet curl degree” is the ratio of the number of sheet feeds that fluttered with respect to the total number of sheet feeds, but the “sheet sheet curl degree” is limited to this. It is not a thing. For example, the maximum value of the fluttering amount (movement amount) of the sheet is distinguished depending on whether it is within the range of X in FIG. 5 or out of the range. Based on the number of times, the ratio to the total number of paper feeds may be obtained to obtain a fluttering ratio.

DESCRIPTION OF SYMBOLS 11 ... Sheet storage part, 12 ... Tray, 19 ... Adsorption conveyance part, 30 ... Air spraying part, 30a ... Floating means, 30b ... Separation means, 31 ... Separation air fan, 33 ... Sputtering air nozzle, 34 ... Separation air nozzle, 36 ... Air blower, 100 ... Printer, 101 ... Printer main body, 102 ... Image forming unit, 103 ... Sheet feeding device, 150 ... Sheet feeding unit, 201 ... Control unit, 202 ... Sheet flapping detection unit, 211 ... CPU, 214 ... Counter, 221 ... Image processing unit, 222 ... High-speed camera, M15 ... Glow fan motor, M16 ... Separation fan motor, Sa ... Top sheet, Sb, Sc ... Second and subsequent sheets

Claims (6)

A sheet support means capable of moving up and down to support the sheet bundle;
Air is blown to the side surface of the sheet bundle supported by the sheet supporting means to float a plurality of sheets above the sheet bundle, and air is blown to the side surfaces of the plurality of sheets that have floated to form a plurality of sheets. An air blowing means provided with a separating means for separating the uppermost sheet,
Suction conveyance means for adsorbing and conveying the separated uppermost sheet with air;
A detection means for detecting the occurrence of flapping in the floating direction of the floated sheet by the air blown from the floating means and the separating means when the uppermost sheet is conveyed by the suction conveying means;
Counting means for counting the number of times the detection means has detected the occurrence of sheet fluttering when a predetermined number of sheets are conveyed;
A sheet conveying operation for conveying a predetermined number of sheets in a state where the air blowing amount of the floating means and the separating means is changed is performed a predetermined number of times, and the detection means detects the flapping of the sheets based on the counting information from the counting means. After obtaining the appropriate air blowing amount of the levitation means and the separating means that generate the largest number of conveyances detected, and after obtaining the appropriate air blowing amount, the air blowing amount becomes the appropriate air blowing amount. And a control unit that controls the floating unit and the separating unit. The levitation means sucks air by the first fan and blows it to the side surface of the sheet bundle,
The separating means is for blowing the air to the side surfaces of the plurality of sheets that have floated by sucking air with a second fan,
The control means obtains the appropriate air blowing amount by changing the air blowing amount of the levitation means and the separating means by changing the rotation speeds of the first fan and the second fan, respectively. 2. The sheet feeding apparatus according to claim 1, wherein the number of rotations of the first fan and the second fan is controlled so as to be an air blowing amount.   The control means has a table for changing the rotation speeds of the first fan and the second fan, and changes the rotation speeds of the first fan and the second fan based on the table, thereby the levitation means. 3. A sheet feeding apparatus according to claim 2, wherein the air blowing amount of the separating means is changed. The detection means includes
A camera that shoots the sides of multiple sheets that have surfaced;
4. An analysis unit that analyzes image information captured by the camera and outputs a signal indicating whether or not the floating sheets move in the flying direction. 5. The sheet feeding apparatus according to claim 1.   The sheet feeding device according to claim 4, wherein the detection unit detects occurrence of flapping of the sheet when the moving amount of the sheet in the flying direction is equal to or greater than a predetermined amount.   An image forming apparatus comprising: an image forming unit that forms an image on a sheet; and the sheet feeding device according to claim 1.

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