JP2008285298A - Sheet feeding apparatus and image forming apparatus - Google Patents

Abstract

To provide a sheet feeding device and an image forming apparatus capable of feeding a sheet appropriately even when information on sheets stacked on a sheet stacking unit is incorrect.
Sheets stacked on a sheet tray 105 that can be moved up and down and driven on the air blowing sheet tray 105 by driving a fan 609 according to air blowing conditions based on sheet information input in advance by an input unit. Ask. The position detectors 607 and 608 detect the position of the uppermost sheet S1 of the rolled sheet. When the position detection units 607 and 608 detect the uppermost sheet S1 that has been rolled by air blowing, the sheet tray 105 is lowered. Further, when the air is blown, the position detection units 607 and 608 do not detect the uppermost sheet S1, and if the elevation detection unit moves up the sheet tray 105, the sheet information input by the input unit is input to the sheet stacking unit 105. Judged to be different from the stacked sheets.
[Selection] Figure 4

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, image forming apparatuses such as printers and copiers have a sheet feeding device for feeding sheets one by one to an image forming unit. Here, as such a sheet feeding device, in addition to using a friction roller, for example, in order to feed sheets one by one from a sheet bundle stacked in a storage which is a sheet storage unit, a sheet bundle end Some parts are made to blow a gas, for example, air.

  In addition, there is one in which a plurality of sheets are floated and separated by blowing air in this way, and further, the sheets are attracted to a conveying belt and sent out (see Patent Document 1).

  FIG. 20 is a diagram showing a configuration of such a conventional sheet feeding device of a so-called air feeding method. In FIG. 20, reference numeral 11 denotes a storage. The storage 11 is provided so as to be freely drawn out to an image forming apparatus main body (not shown), and includes a sheet tray 12 that can be moved up and down on which a plurality of sheets (sheet bundles) are placed.

  Further, a rear end regulating plate 13 that regulates a rear end position that is an upstream end of the sheet in the sheet feeding direction, and a side end position that is an end in a direction orthogonal to the sheet conveying direction (hereinafter referred to as a width direction). A transverse restriction plate 14 for restriction is provided. The rear end restricting plate 13 and the lateral restricting plate 14 are configured so that the positions can be arbitrarily changed according to the size of the sheet. In addition, a slide rail 15 or the like for storing the storage 11 in a main body of the image forming apparatus (not shown) so as to be drawable is provided.

  Reference numeral 30 denotes an adsorption conveyance unit. The adsorption conveyance unit 30 adsorbs and conveys a separation fan 32, a separation duct 32 including a separation nozzle 33 and a separation nozzle 34, an adsorption fan 36, an adsorption shutter 37, and a sheet. A belt 21 and the like are provided. FIG. 20 shows a state in which after the user pulls out the storage case 11, the sheet is set and the storage case 11 is again stored in the image forming apparatus main body.

  When the storage 11 is stored in this way, the sheet tray 12 starts to rise in the direction indicated by the arrow A in FIG. 21 by a driving unit (not shown), and the distance between the upper surface of the sheet bundle on the sheet tray and the suction conveyance belt 21 is B. At the position where it becomes, and prepare for a feeding signal from a control unit (not shown).

  Next, when a feeding signal is input from a control unit (not shown), the separation fan 31 is activated and sucks air in the direction of arrow C as shown in FIG. This air is blown from the firing nozzle 33 and the separation nozzle 34 via the separation duct 32 to the sheet bundle ST from the directions D and E in the drawing, and accordingly, several sheets SA located at the upper part of the sheet bundle ST are provided. Emerges. On the other hand, the suction fan 36 is operated to discharge air in the direction F in the drawing. At this time, the suction shutter 37 is still closed.

  Thereafter, when a predetermined time elapses after the feeding signal is detected and the floating of several sheets SA is stabilized, the suction shutter 37 is rotated in the arrow G direction as shown in FIG. As a result, a suction force in the H direction in the drawing is generated from a suction hole (not shown) formed in the suction conveyance belt 21, and the uppermost sheet SB (hereinafter referred to as the uppermost sheet) among the several sheets SA that have floated. ) Is adsorbed to the adsorbing and conveying belt 21.

  Next, after the uppermost sheet SB is adsorbed in this way, the adsorbing and conveying belt 21 is rotated by rotating the belt driving roller 41 around which the adsorbing and conveying belt 21 is wound as shown in FIG. The uppermost sheet SB is conveyed in the arrow K direction. Finally, the uppermost sheet SB is pulled out by the suction conveyance belt 21 by the drawing roller pair 42 rotating in the L and M directions in the drawing, and then sent to the next conveyance path.

  By the way, in such a conventional sheet feeding apparatus, for example, as shown in FIG. 25, position detection sensors 101 and 102 for detecting the position of the uppermost sheet SB that is levitated are provided. The position detection sensors 101 and 102 determine whether or not the uppermost sheet SB is at a floating position within a predetermined range. When the uppermost sheet SB is out of the predetermined range, the sheet tray is moved up and down. Accordingly, the position of the levitated uppermost sheet SB is controlled so as to be positioned within a predetermined range in which the sheet can be fed (see Patent Document 2).

  In the case of such a sheet feeding apparatus, for example, when the uppermost sheet SB is below the predetermined range during the air discharge operation, the sheet tray is raised and the uppermost sheet SB is above the predetermined range. Controls to lower the sheet tray.

  In FIG. 25, two position detection sensors 101 and 102 are used as the position detection unit for detecting the uppermost sheet SB that is floating, but the distance from the suction conveyance belt 21 to the uppermost sheet SB is shown as follows. You may use the distance measurement sensor to measure.

  Further, in the conventional sheet feeding apparatus, for example, since the sheet floating amount varies depending on the type (material, thickness, weight, etc.) of the sheet, the air discharge amount is controlled so that the optimum floating amount is obtained. There is something that was made. For example, as shown in FIG. 26, a distance measuring sensor 103 is arranged in the vicinity of the leading end in the sheet feeding direction, and the distance measuring sensor 103 recognizes the distance of the uppermost sheet SB levitated from the belt surface. (See Patent Document 3).

  In the case of such a sheet feeding device, the amount of air discharged is controlled by controlling the rotation speed of the separation fan 31 based on the distance information from the distance measuring sensor 103, and the floating amount of the uppermost sheet SB is determined. The optimum amount of levitation is set. For example, when the sheet is thin or light, the rotation speed of the separation fan 31 is controlled to be low (slow), and when the sheet is thick or heavy, the rotation speed of the separation fan 31 is increased (fast). Control to be.

  In addition, by inputting the type (material, thickness, weight, etc.) of the sheets stacked on the sheet tray from the operation unit of the image forming apparatus, the air discharge amount is uniquely determined according to the input sheet type. Some controls have been proposed to determine automatically.

JP-A-7-196187 JP-A-2005-272019 JP-A-7-89625

  However, when the conventional sheet feeding apparatus controls the floating position of the uppermost sheet and keeps the position of the uppermost sheet within a predetermined range, the sheets stacked on the sheet tray are optimally rolled. It cannot be determined whether or not it is in a state.

  For this reason, if the sheets stacked on the sheet tray are thin or light, and the rotation speed of the separation fan is made faster than the target, the sheet rolling state will not be stable, jamming, skewing, misalignment, scratches, etc. Problems such as breakage and dirt may occur. Also, if the sheets stacked on the sheet tray are thick or heavy, and the separation fan speed is slower than the target, appropriate air will not flow between the sheets, causing problems such as double feeding of sheets. May occur.

  Also, in the case of controlling the air discharge amount by recognizing the distance from the belt surface to the uppermost sheet and controlling the rotation speed of the separation fan based on this distance, the separation fan is changed each time the sheet type is changed. It is necessary to control to change the number of rotations. For this reason, it takes time to start feeding.

  By the way, in the case where control is performed so that the information regarding the sheet type is input from the operation unit and the air discharge amount is uniquely determined according to the input information, the sheet type information is actually loaded on the sheet tray. May be entered incorrectly with the type of sheet that was entered.

  In this case, the rotation speed of the separation fan becomes an inappropriate value, and as a result, the above-described problems such as sheet double feeding, skew feeding, position shift, scratches, breakage, and dirt may occur. That is, there is a problem that if the information regarding the sheet type is input incorrectly, the sheet cannot be fed properly.

  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 appropriately feed sheets even when the sheet information stacked on the sheet tray is incorrect. It is intended to provide.

  The present invention adsorbs and conveys a sheet tray that can be moved up and down, an air blowing unit that has a fan that blows air onto the sheets stacked on the sheet tray and spreads the sheets, and an uppermost sheet of the rolled sheets. A suction conveyance mechanism, and a position detection unit that detects the position of the uppermost sheet of the sheets stacked on the sheet tray wound by the air blowing, and when the sheet is rolled by the air blowing, In a sheet feeding device that controls to lower the sheet tray based on detection of the uppermost sheet by the position detection unit, an elevation detection unit that detects elevation of the sheet tray, and a stacking unit that is stacked on the sheet tray An input unit for inputting sheet information corresponding to the sheet, and an air blowing condition based on the sheet information input from the input unit Accordingly, when the air blowing unit blows air, the position detecting unit does not detect that the uppermost sheet is in a sheet feedable position, and the elevation detecting unit detects the rise of the sheet tray. In this case, it is determined that the sheet information input by the input unit is different from the sheets stacked on the sheet tray.

  As in the present invention, when the sheet is rolled, if the position detection unit does not detect the uppermost sheet and the sheet tray is raised, it is determined that the sheet information stacked on the sheet tray is different from the actual sheet. By doing so, the sheet can be fed appropriately.

  The best mode for carrying out the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a printer which is an example of an image forming apparatus including a sheet feeding device according to the first embodiment of the present invention.

  In FIG. 1, reference numeral 1000 denotes a printer, and the printer 1000 includes a printer main body 1001 and a scanner 2000 disposed on the upper surface of the printer main body 1001.

  Here, the scanner 2000 that reads a document includes a scanning optical system light source 201, a platen glass 252, a document pressure plate 251 that opens and closes, a lens 204, and a light receiving element (photoelectric conversion) 205. The image processing unit 206 also includes a memory unit 208 for storing the image processing signal processed by the image processing unit 206.

  When reading the original, the original (not shown) placed on the platen glass 252 is read by irradiating light with the scanning optical system light source 201. Then, the read original image is processed by the image processing unit 206, converted into an electrically encoded electric signal 207, and transmitted to the laser scanner 111 as image forming means.

  Note that image information processed and encoded by the image processing unit 206 may be temporarily stored in the memory unit 208 and transmitted to the laser scanner 111 as necessary by a signal from the controller 120 described later.

  A large capacity paper deck 1002 is connected to the side surface of the printer main body 1001. Further, the printer main body 1001 includes a sheet conveying device 1004 that conveys the sheet S fed from the paper deck 1002 to the image forming unit 1005, a controller 120 serving as a control unit for controlling the printer 1000, and the like. Yes.

  Here, the sheet conveying apparatus 1004 includes a registration roller unit including a registration roller pair 130 and a registration roller pair 110. The sheet S fed from the paper deck 1002 passes through the sheet conveyance path 109 and is guided to the registration roller pair 110 through the pre-registration roller pair 130. Further, the sheet S is thereafter conveyed to the image forming unit 1005 by the registration roller pair 110.

  The image forming unit 1005 includes a photosensitive drum 112, a laser scanner 111, a developing device 114, a transfer charger 115, a separation charger 116, and the like. When an image is formed, a laser beam from the laser scanner 111 is folded back by the mirror 113 and applied to the exposure position 112a on the photosensitive drum that rotates clockwise, thereby forming a latent image on the photosensitive drum. Is done. Further, the latent image formed on the photosensitive drum in this manner is visualized as a toner image by the developing device 114 thereafter.

  The toner image on the photosensitive drum is then transferred to the sheet S by the transfer charger 115 in the transfer unit 1006. Further, the sheet S on which the toner image is transferred in this manner is electrostatically separated from the photosensitive drum 112 by the separation charger 116 and then conveyed to the fixing device 118 by the conveyance belt 117 to fix the toner image. Thereafter, the paper is discharged by a discharge roller 119. In addition, a paper discharge sensor 121 is provided in the conveyance path between the fixing device 118 and the paper discharge roller 119, and the passage of the sheet S discharged by the paper discharge sensor 121 can be detected.

  In this embodiment, the printer main body 1001 and the scanner 2000 are separate, but the printer main body 1001 and the scanner 2000 may be integrated. In addition, the printer main body 1001 functions as a copying machine when a processing signal of the scanner 2000 is input to the laser scanner 111, and functions as a FAX when a FAX transmission signal is input. Furthermore, if an output signal of a personal computer is input, it functions as a printer.

  Conversely, if the processing signal of the image processing unit 206 of the scanner 2000 is transmitted to another FAX, it functions as a FAX. If the scanner 2000 is equipped with an automatic document feeder 250 as shown by a two-dot chain line instead of the original pressure plate 251, the original can be automatically read.

  Incidentally, the paper deck 1002 includes an upper sheet storage portion 303 that stores the sheet bundle ST and a lower sheet storage portion 103. A rear end regulating plate 104 is provided on the rear end side of the sheet bundle ST in the lower sheet storage unit 103 in the sheet conveyance direction (arrow A direction). The trailing edge regulating plate 104 moves according to the size of the sheet bundle ST, and the trailing edge side of the sheet bundle ST is aligned so that the leading edge side of the sheet bundle ST is aligned with the leading edge side of the sheet storage unit 103 in the sheet conveying direction. Is to regulate.

  The paper deck 1002 also includes upper and lower sheet separating and feeding devices 202A and 107, which are sheet feeding devices that separate and feed the sheets stored in the upper and lower sheet storage portions 303 and 103 with air. Yes.

  Further, the paper deck 1002 includes a control unit 300 that controls sheet feeding by the upper and lower sheet separating and feeding devices 202A and 107. The control unit 300 receives signals indicating the passage of the sheet from the sheet detection sensors 17 to 19 and 24 to 26 illustrated in FIGS. 1 and 2. Also, sheet information such as the size and type of the sheets stored in the upper and lower sheet storage units 303 and 103, and the basis weight are input from the sheet size input unit 30 shown in FIG.

  In FIG. 1, 202 and 102 are suction conveyance belts as suction conveyance mechanisms provided in the upper and lower sheet separating and feeding apparatuses 202A and 107, and 10 and 20 are sheets adsorbed by the adsorption conveyance belts 102 and 202, respectively. A pair of drawing rollers to be pulled out. Reference numerals 11 to 16 and 21 to 23 denote pairs of conveying rollers, and reference numerals 305 and 105 denote sheet trays capable of moving up and down on which the sheet bundle ST is stacked.

  The drawing roller pairs 10 and 20 are independent of the drawing motors M10 and M20 shown in FIG. 2, the conveying roller pairs 11 to 16 are independent of the conveying motors M11 to M16, and the conveying roller pairs 21 to 23 are independent of the conveying motors M21 to M23, respectively. Driven. The sheet trays 305 and 105 are moved up and down by lifter motors M05 and M205.

  Here, FIG. 3 is a diagram illustrating a configuration of the upper sheet storage unit 303 that separates and feeds the sheet with air. In FIG. 3, F151 is a fan, 151 is a nozzle, F152 is a separation fan, 152 is a separation nozzle, 202 is a suction conveyance belt, and F150 is a suction fan. The suction conveyance belt 202 is driven by a driving roller 202a that is rotationally driven by a suction conveyance belt motor M102 shown in FIG.

  When feeding sheets, first, in the upper sheet separating and feeding apparatus 202A, the whirling fan F151 is rotated as a pre-feeding operation, whereby the whirling nozzle 151 and the separation nozzle 152 are directed toward the upper part of the sheet bundle ST. Air is blown out each time. As a result, several sheets at the top of the sheet bundle ST float while being rolled. Note that an air blowing unit that blows air on the sheets stacked on the sheet tray 305 by the blowing fan F151, the rolling nozzle 151, and the separation nozzle 152 is configured.

  Next, when a feeding start signal is transmitted from the control unit 300, the suction fan F150 rotates, and thereby a negative pressure is generated in the suction conveyance belt 202. That is, a suction force is generated. As a result, suction of the sheet is started, and only one uppermost sheet S1 of the sheet bundle ST is attached to the suction conveyance belt 202. Then, after a predetermined time, the suction conveyance belt 202 starts rotating with the suction conveyance belt motor M102 in a state where the sheet S1 is adhered, and the sheet S1 is conveyed in the arrow A direction.

  Next, when the leading edge of the sheet S1 reaches the driving roller portion, the leading edge portion of the sheet is released from the suction force by the suction fan F150, and is separated from the suction conveyance belt 202 and transferred to the drawing roller pair 20. When the leading edge of the sheet S1 reaches the drawing roller pair 20 in this way, the negative pressure by the suction fan F105 is released, and thereby the sheet S1 is conveyed only by the conveying force of the drawing roller pair 20.

  Next, after the trailing end of the sheet S1 is pulled out from the suction conveyance belt 202, when the feeding start signal is transmitted again from the control unit 300, the feeding operation as described above is started, and the next sheet is started. S2 is separated and fed. In the present embodiment, whispering fan F151 is operated as a pre-feeding operation before the feeding start signal is transmitted. However, after the feeding start signal is transmitted, whispering fan F151 is operated. You may control so that it may.

  FIG. 4 is a diagram illustrating a configuration of the lower sheet storage unit 103. In FIG. 4, 612 is a paper feed fan, and 613 is a paper feed fan duct. The wind pressure in the suction direction generated by rotating the paper feed fan 612 is applied to the suction conveyance belt 102 through the paper feed fan duct 613, so that the uppermost sheet S1 of the sheet bundle ST is attracted to the suction conveyance belt 102. I am doing so.

  Further, reference numeral 609 denotes a separation fan provided for the purpose of spreading the sheet bundle ST stored in the sheet tray 105 prior to the sheet feeding operation, and reference numeral 610 denotes a separation fan duct. Then, the wind pressure in the discharge direction generated by rotating the winding fan 609 is applied to the vicinity of the uppermost sheet S1 of the sheet bundle ST by the blowing fan duct 610, so that a plurality of sheets can be simultaneously fed during the sheet feeding operation. Prevents paper being fed (double feed).

  When feeding sheets, first, the fan 609 is rotated as a pre-feeding operation, and the wind fan duct 610 applies wind pressure in the discharge direction to the vicinity of the uppermost sheet S1 of the sheet bundle ST. Float several sheets on top of ST. Note that an air blowing unit that blows air on the sheets stacked on the sheet tray 105 by the blowing fan 609 and the blowing fan duct 610 is configured.

  Next, when a feed start signal is transmitted from the control unit 300, the paper feed fan 612 is rotated, and the wind pressure in the suction direction generated thereby is applied to the suction conveyance belt 102 through the paper feed fan duct 613. As a result, the uppermost sheet S1 of the sheet bundle ST is adsorbed to the adsorbing and conveying belt 102.

  Then, after a predetermined time, the suction conveyance belt motor M102 is rotated. As a result, the suction conveyance belt 102 starts to rotate with the sheet S1 adhered, and the sheet S1 is conveyed in the direction of arrow A. Thereafter, the sheet S1 adsorbed by the adsorption conveyance belt 102 is conveyed to the paper feed retry sensor 620 and the drawing roller 10 side.

  The sheet tray 105 is moved up and down by driving a lifter motor M205 via a pulley 603. Here, the encoder 160 shown in FIG. 2 is attached to the lifter motor M205, and the encoder 160 can know the drive amount of the lifter motor M205, that is, the movement amount of the sheet tray 105.

  A lower limit detection sensor 605 for detecting the lower limit position of the sheet tray 105 is disposed on the bottom surface of the lower sheet storage unit 103. In the present embodiment, the elevation detection unit that detects the elevation of the sheet tray 105 is configured by the encoder 160 described above.

  That is, the movement (lifting / lowering) direction of the sheet tray 105 can be known from the rotation direction of the encoder 160. The moving direction of the sheet tray 105 can also be known from the control signal of the suction conveyance belt motor M102.

  On the other hand, above the sheet tray 105, a sheet presence / absence detection sensor 606 for detecting the presence / absence of a sheet, a sheet floating lower limit sensor 607 for detecting the position of the uppermost sheet lifted by the wind pressure by the rolling fan 609, and a sheet floating upper limit sensor 608 is arranged.

  Here, the sheet presence / absence detection sensor 606 is a mechanical sensor that detects a sheet by a flag, and the sheet floating lower and upper limit sensors 607 and 608 are optical sensors that detect the sheet by light.

  Further, the sheet presence / absence detection sensor 606 is disposed below the sheet floating lower limit and upper limit sensors 607 and 608. Thus, when the sheet bundle ST stacked on the sheet tray 105 rises to the sheet feeding start position, the sheet presence / absence detection sensor 606 moves the upper surface of the sheet bundle ST before the sheet floating lower and upper limit sensors 607 and 608. It can detect and detect the presence or absence of a sheet.

  Further, the sheet floating lower limit sensor 607 that is the first detection unit is adjusted in sensitivity so that the floating sheet positioned below the sheet floating upper limit sensor 608 that is the second detection unit can be detected. Thus, by adjusting the sensitivity of the two sensors 607 and 608 in this way, it is possible to detect whether the topmost sheet that has floated is located within a predetermined range in which the sheet can be fed.

  Note that when the sheet is blown by blowing air, the detection state of the sheet floating lower and upper limit sensors 607 and 608 and the sheet feeding state that constitute the position detection unit that detects the position of the uppermost sheet of the sheets stacked on the sheet tray Will be described later.

  Here, FIG. 4 shows a state in which the sheet S1 is adsorbed to the adsorbing and conveying belt 102. When the sheet floating lower limit and upper limit sensors 607 and 608 detect the sheet floating position, as shown in FIG. This is performed while only the fan 609 is operating. In other words, the sheet floating fan 612 is not operated, and the sheet fan 609 is operated, while the sheet floating lower limit and upper limit sensors 607 and 608 are detected, and the sheet S1 flying position is detected. The raising and lowering of the sheet tray 105 is controlled.

  Note that the sheet feeding standby position of the sheet bundle ST when both the sheet feeding fan 612 and the separation fan 609 are in the non-operating state may be the on-edge of the sheet floating lower limit sensor 607 or the on-edge of the sheet presence / absence detection sensor 606. Absent.

  Next, the logic of the sheet floating lower limit sensor 607 and the sheet floating upper limit sensor 608 will be described with reference to FIG.

  If the sheet feeding standby position of the sheet bundle ST when both the sheet feeding fan 612 and the separation fan 609 are in the non-operating state is the on-edge of the sheet floating lower limit sensor 607, the state shown in FIG. It becomes. In such a standby state, as shown in FIG. 6B, the uppermost sheet S1 is below the lower limit of detection (first detection position) of the sheet floating upper limit sensor 608 shown in FIG. Is located.

  When the winding fan 609 is driven in this state, several sheets above the sheet bundle ST are rolled up, and the uppermost sheet S1 of the sheet bundle ST floats. As a result, the uppermost sheet S1 moves above the detectable lower limit (second detection position) of the sheet floating upper limit sensor 608 above the detectable lower limit of the sheet floating lower limit sensor 607 shown in FIG.

  Thereafter, as shown in FIG. 5, the sheet tray 105 is moved up and down so that the uppermost sheet S <b> 1 that has floated enters a position between the sheet lift lower limit sensor 607 and the sheet lift upper limit sensor 608 (paper surface control optimal position). Be controlled.

  4 and 5, the sheet floating lower and upper limit sensors 607 and 608 are arranged in the sheet feeding direction. However, by arranging them in the width direction that is orthogonal to the sheet feeding direction, More accurate detection is possible. A distance measuring sensor capable of measuring the distance may be used instead of the sheet floating lower limit and upper limit sensors 607 and 608.

  FIG. 7 is a block diagram showing the configuration of the controller 120 of the printer main body 1001 and the control unit 300 of the paper deck 1002 shown in FIG.

  The controller 120 of the printer main body 1001 includes a CPU 201, a ROM 206, a RAM 205, a communication interface (I / F) 207, an input / output port 204, an image processing unit 170, and an image memory unit 3.

  The CPU 201 performs basic control of the printer main body 1001. A ROM 206 in which a control program is written, a RAM 205 for performing processing, and an input / output port 204 are connected by an address bus and a data bus. A part of the RAM 205 is a backup RAM in which data is not erased even when the power is turned off. Various input devices such as a motor and a clutch controlled by the printer main body 1001 and an input device such as a sheet detection sensor for detecting the position of the sheet are connected to the input / output port 204.

  Then, the CPU 201 sequentially performs input / output control via the input / output port 204 in accordance with the contents of the control program stored in the ROM 206, and executes image forming processing. The CPU 201 is connected to an operation unit 203 which is an input unit for inputting sheet information corresponding to the sheets stacked on the sheet tray 105, and the CPU 201 controls a display unit and a key input unit of the operation unit 203.

  The user instructs the CPU 201 to switch the image forming operation mode and display through the key input unit. The CPU 201 displays the operation state of the printer main body 1001 and the key input on the display unit of the operation unit 203 shown in FIG. The operation mode set by is displayed. Further, the CPU 201 is connected to an image processing unit 170 that processes a signal converted into an electrical signal by the image sensor unit 205 and an image memory unit 3 that stores the processed image.

  On the other hand, the control unit 300 of the paper deck 1002 includes a CPU 2201, a ROM 2202, a RAM 2203, a communication interface (I / F) 2204, and an input / output port 2205 in order to realize the operation described with reference to FIG.

  The CPU 2201 is connected to the operation unit 2206 and receives detection results from the above-described sheet floating lower limit and upper limit sensors 607 and 608 via the input / output port 2205. Based on the detection result, a drive command is output to the lifter motor M 205, the separation fan 609, and the paper feed fan 612.

  FIG. 8 is a diagram illustrating a configuration of the operation unit 203 provided in the printer main body 1001. The operation unit 2206 connected to the control unit 300 of the paper deck 1002 can have the same configuration.

  In FIG. 8, reference numeral 3001 denotes a display unit that displays various messages such as operation states of the printer main body 1001 and the paper deck 1002 and work instructions to the user, work procedures, and the like. Further, the surface of the display unit 3001 is constituted by a touch panel, and acts as a selection key by touching the surface.

  3002 is a numeric keypad for inputting numbers, 3003 is a start key for starting a copying operation, and 3004 is an application mode selection key. Information (conditions) on sheet type such as sheet surface material, basis weight, and surface smoothness Can be entered.

  For example, as shown in FIG. 9, the material (type) of the sheet accommodated in the paper deck can be selected from the display unit 3001. The sheet information such as the sheet surface material, basis weight, and surface smoothness may be set finely.

  The ROM 2202 of the control unit 300 of the paper deck 1002 has a rotation speed at which the optimal rotation air can be obtained for the rotation speeds of the fan 609 and F151 according to the material of the sheet shown in FIG. It has a table to change.

  FIG. 10 is a table showing a relationship between the basis weight of a sheet, which is one of sheet information recorded in the ROM 2202, and the number of rotations of the fan.

  When the basis weight of the sheet is input from the operation screen, the control unit 300 of the paper deck 1002 serving as the rotation speed control unit rotates based on this table so that the air blowing conditions (wind pressure) by the fan 609 are optimized. The number of rotations of the fan 609 is set so as to be a number. If no setting is made, the normal plain paper 208 is set. In addition to FIG. 9, for example, as shown in FIG. 11, the material (type) of the sheet may be set finely.

  FIG. 12 shows a normal state of the uppermost sheet performed before the sheet feeding operation is started when the rotation speed of the rolling fan 609 is set in accordance with, for example, the sheet basis weight (sheet condition) input in this way. It is a figure explaining paper surface control.

  When the blower fan 609 operates in the state shown in FIG. 12A, air is blown onto the upper portion of the sheet bundle ST as shown in FIG.

  By blowing air in this way, the uppermost sheet of the sheet bundle ST is between the sheet floating lower limit and upper limit sensors 607 and 608 or the sheet floating upper limit sensor without performing the lifting / lowering operation of the sheet tray 105. Move upward from 608.

  When the sheet floats above the sheet floating upper limit sensor 608 in this way, the sheet tray 105 is controlled to finally descend by ΔL1, as shown in FIG. Thus, after that, when sheet feeding is started and air is blown, the uppermost sheet S1 can move to the sheet feedable position between the sheet floating lower limit and upper limit sensors 607 and 608. Become.

  By the way, such sheet surface control is performed when the sheet condition (information) set on the operation screen matches the sheets stacked on the sheet tray 105. However, the sheet conditions set on the operation screen may differ from the sheets actually stacked on the sheet tray 105.

  For example, when thin paper is selected from the operation screen as shown in FIG. 9, the fan 609 is controlled to operate at 25% PWM drive as shown in FIG. However, if the thickest opening is actually stacked on the sheet tray 105, the optimum fan PWM value of the thickest opening is 100%. Therefore, sufficient air blowing is not performed with 25% PWM driving.

  In this case, when the blower fan 609 operates in the state shown in FIG. 13A, air is blown onto the upper part of the sheet bundle ST. However, as shown in FIG. 13B, the uppermost sheet S1 of the sheet bundle ST is It will not be enough to float. That is, the uppermost sheet S1 does not enter between the sheet floating lower limit sensor 607 and the sheet floating upper limit sensor 608.

  Therefore, after the rotation of the rolling fan 609 is stabilized (predetermined time), the elevation of the sheet tray 105 is controlled so that the uppermost sheet S1 enters between the sheet floating lower limit sensor 607 and the sheet floating upper limit sensor 608. As a result, the sheet tray 105 is raised by ΔL2 as shown in FIG.

  That is, the control unit 300 of the paper deck 1002 serving as a determination unit sets the sheet condition (information) set on the operation screen and the actual sheet tray 105 in the sheet surface control of the uppermost sheet performed before starting the sheet feeding operation. It is determined whether the stacked sheets match. When it is determined that the sheet condition (information) is different from the sheets actually stacked on the sheet tray 105, the sheet tray 105 is raised after the rotation of the rolling fan 609 is stabilized.

  When the sheet tray 105 is raised as described above, in the present embodiment, the sheet condition (information) set on the operation screen and the sheets stacked on the sheet tray 105 are different as shown in FIG. It is controlled to notify a warning that there is a possibility of being.

  When the sheet tray 105 is raised, the PWM value of the rolling fan 609 is controlled so as to be gradually or at once, and the uppermost sheet S1 enters between the sheet floating lower limit sensor 607 and the sheet floating upper limit sensor 608. Like that.

  When the uppermost sheet S1 enters the sheet feedable position between the sheet floating lower limit sensor 607 and the sheet floating upper limit sensor 608 as described above, the sheet tray 105 is thereafter controlled to be lowered by ΔL1. .

  Note that if the sheet tray 105 does not descend even if the PWM value of the fan 609 is gradually or rapidly increased, for example, the fan 609, the sheet lifting lower and upper limit sensors 607 and 608, the tray lifting motor 604 An abnormality may be considered. For this reason, in this case, as shown in FIG. 14B, control is performed to display (notify) that effect.

  By the way, if it is detected that the sheet tray 105 is lowered and lowered from the sheet feeding standby position by gradually or suddenly increasing the PWM value of the separating fan 609 in this manner, the separating fan is detected at that time. The PWM setting value of 609 is fixed.

  For example, when the PWM value of the fan 609 is gradually or rapidly increased from the state of FIG. 13, the PWM value of the fan 609 becomes 100%, and the sheet tray 105 is 2.0 mm from the sheet feeding standby position. Suppose that it descends.

  In this case, referring to the table of the relationship between the PWM value of the rolling fan 609, the sheet type (basis weight), and the sheet tray movement amount from the sheet feeding standby position shown in FIG. It can be determined that the sheet has the thickest mouth. When such a determination is made, the user is informed on the operation screen as shown in FIG. 16 that the sheets stacked on the sheet tray 105 are the thickest slot (long thick paper), and the user is allowed to confirm. It becomes possible.

  In the present embodiment, as shown in FIG. 9 described above, the display unit 3001 is provided with a material automatic setting button 213 for automatically setting the material of the sheet and a material manual setting button 212 for manually setting the material. Yes.

  For example, when the display as shown in FIG. 16 is made, the sheet information is input by operating the material manual setting button 212 which is a manual input unit, and is changed to the PWM value of the fan 609 according to the sheet information. To be controlled. Alternatively, sheet information is automatically input by operating an automatic material setting button 213 that is an automatic input unit, and the PWM value of the fan 609 is changed according to the sheet information.

  Further, since the sheet condition (basis weight) and the movement amount of the sheet tray 105 at each PWM value of the winding fan 609 are in the relationship as shown in FIG. 17, the winding fan PWM value, the sheet basis weight, and the movement amount of the sheet tray are It is possible to determine uniquely.

That is, in FIG. 17, the PWM value of the fan 609 is displayed in increments of 25%, the sheet basis weight is displayed in increments of 50 g / m ² , and the movement amount of the sheet tray 105 is displayed in increments of 1 mm. Thereby, if two of these three conditions are determined, the remaining one can be determined.

  Next, processing before the sheet feeding operation in the paper deck 1002 is started will be described with reference to the flowchart of FIG.

  First, in the state where sheets are stacked on the sheet tray 105 and the sheets are waiting at the sheet feeding standby position, when a preliminary firing signal or a pre-feeding signal is detected, the control unit 300 of the paper deck 1002 is detected. Turns on the fan 609 (S101). At this time, the winding fan 609 is controlled so as to rotate at a winding pressure (PWM value) optimum for the stacked sheets. As a result, air is blown onto the upper portion of the sheet bundle ST as shown in FIG.

  Next, when a predetermined time elapses until the rotation of the fan 609 is stabilized (Y in S102), the control unit 300 turns on the lifter motor M205 that raises and lowers the sheet tray 105 (S103). Accordingly, the uppermost sheet of the sheet bundle ST moves between the sheet floating lower limit sensor 607 and the sheet floating upper limit sensor 608 or above the sheet floating upper limit sensor 608 (Y in S104). Even if the sheet tray 105 is not moved up and down, when the uppermost sheet is between the sheet floating lower limit sensor 607 and the sheet floating upper limit sensor 608, the sheet tray 105 is stopped.

  By the way, when the sheet condition set on the operation screen matches the sheet stacked on the sheet tray 105, the sheet tray 105 is finally set as shown in FIG. Control is performed so as to decrease by ΔL1. When the sheet tray 105 is lowered by ΔL1 in this way (N in S104), the control unit 300 controls to perform a normal paper surface control operation (S113).

  On the other hand, when the sheet tray 105 is raised, there is a high possibility that the preset sheet condition and the actually stacked sheet are different. For this reason, when the alarm display is set in advance (Y in S105), the fact is displayed as shown in FIG.

  On the other hand, when the alarm display is not performed (N in S105), the control unit 300 controls to increase the PWM value of the burning fan 609 and to increase (increase) the rotation speed of the burning fan 609 (S106). . Here, if the sheet tray 105 does not descend even when the number of rotations of the fan 609 is increased thereafter (N in S107), it is determined that the fan 609 or the like is abnormal, and FIG. 14B described above. As shown in FIG. 5, an error is displayed on the operation screen (S114).

  On the other hand, when the uppermost sheet moves upward from the sheet floating upper limit sensor 608 by increasing the number of rotations of the fan 609, the sheet tray 105 is lowered. When the sheet tray 105 is lowered as described above (Y in S107), the control unit 300 stops increasing the PWM of the blowing fan 609 and stops the rotation speed UP of the blowing fan 609 (S108). ). Further, control is performed so as to latch the PWM value immediately after the increase.

  Next, the PWM value of the latched fan 609, the actual amount of movement of the sheet tray 105 from the sheet feeding standby position, the sheet condition and the movement of the sheet tray at each PWM value of the fan 609 shown in FIG. A table showing the relationship with the quantity is compared (S109). As a result, the material of the actually stacked sheets is determined (S110).

  Then, after the material is determined in this way, when it is controlled so as to be notified on the operation screen (Y in S111), control is performed so as to notify the material of the sheet currently stacked on the operation screen. To do.

  In addition, when it is not controlled to notify on an operation screen (N of S111), it controls to change a material setting automatically (S112). Note that the selection of whether or not to automatically change the material placement may be performed from the operation screen.

  As described above, in the present embodiment, when the sheet tray 105 is lifted when the sheet is fed, it is determined that the sheet information stacked on the sheet tray 105 is incorrect. Thereby, even when the information on the sheets stacked on the sheet tray 105 is incorrect, the sheets can be fed properly. Further, since it can be determined in advance that the material of the input sheet and the material of the sheets stacked on the sheet tray 105 are different, it is possible to eliminate miscopying with an incorrect setting.

  Further, when it is determined that the input sheet information is different, the material can be uniquely determined from the relationship between the number of rotations of the fan 609 and the amount of movement of the sheet tray 105. Trouble can be solved.

  Next, a second embodiment of the present invention will be described.

  FIG. 19 is a schematic configuration diagram of a printer that is an example of an image forming apparatus including the sheet feeding apparatus according to the present embodiment. In FIG. 19, the same reference numerals as those in FIG. 1 described above indicate the same or corresponding parts.

  In FIG. 19, reference numeral 1002 ′ denotes a sheet feeding device provided in the printer main body 1001. The sheet feeding apparatus 1002 ′ includes a separation unit including a cassette 100, a pickup roller 101 that is a sheet feeding unit, a feed roller 102, and a retard roller 103.

  The sheets S in the cassette 100 are separated and fed one by one by the action of the pickup roller 101 that moves up and down / rotates at a predetermined timing and the separation unit. A paper feed sensor 104 is provided in the vicinity of the feed roller 102 and the retard roller 103 on the downstream side in the sheet conveyance direction. The paper feed sensor 104 can detect the passage of the sheet S.

  A finisher 1006 performs a bookbinding process on the sheet bundle, and a sheet insertion device 1003. The sheet insertion device 1003 includes sheet feeding devices 302 and 303. Here, the sheet feeding devices 302 and 303 feed sheets on which image formation is not performed for use as a slip sheet, a front cover, a back cover, a partition paper, or the like of a sheet bundle created by the printer main body 1001. To do. In addition, an image-formed sheet, a sheet that is not desired to be conveyed in the printer main body 1001, and the like are fed.

  These sheet feeding devices 302 and 303 insert sheets such as slip sheets, front cover, and back cover between sheets sequentially conveyed from the printer main body 1001 and sequentially feed the sheets to the finisher 1006. .

  In the printer 1000 provided with such a sheet insertion device 1003, the sheet S discharged from the printer main body 1001 is immediately guided to the sheet conveyance path 301 of the sheet insertion device 1003. Here, the sheet conveyance path 301 is formed from the entrance portion to the paper discharge portion. A sheet feeding device 302 is arranged above the sheet conveyance path 301 and a sheet feeding device 303 is arranged below the sheet conveyance path 301. Has been.

  The sheet feeding apparatuses 302 and 303 insert sheets as described above between sheets sequentially conveyed from the printer main body 1001 and sequentially feed the sheets to the finisher 1006.

  Here, the sheet feeding device 303 includes a sheet storage unit 306 that stores the sheet bundle ST, and a rear end regulating plate 307 is provided on the rear end side in the sheet conveyance direction indicated by the arrow of the sheet bundle ST. Is provided. The rear end regulating plate 307 moves according to the size of the sheet bundle ST, and the rear end side of the sheet bundle in the transport direction is aligned so that the front end side of the sheet bundle is aligned with the front end side of the sheet storage unit 306 in the transport direction. It is regulated.

  The sheet feeding device 303 employs an air feeding mechanism as shown in FIG. 4 described above in order to perform stable separation feeding for various types of sheets. Further, the sheet feeding apparatus 302 employs an air feeding mechanism as shown in FIG.

  As a result, when the sheet is fed, the sheet in the sheet storage unit 306 is conveyed in the direction of the arrow while being stuck to the suction conveyance belt 308, and thereafter, the conveyance speed V2 only by the conveyance force of the drawing roller pair 312. It is conveyed by. Also in the sheet feeding device 302, the sheet is conveyed in the direction of the arrow while being stuck to the suction conveyance belt 302b, and thereafter conveyed at the conveyance speed V2 only by the conveyance force of the pulling roller pair 302a.

  Thereafter, the sheets from the sheet feeding apparatuses 302 and 303 are merged with the sheet conveyed from the printer main body 1001 at a merging point 320 in the middle of the sheet conveying path 301 and conveyed to the finisher 1006. When the feeding start signal is transmitted again from the control unit 131 after the trailing edge of the sheet has come off from the suction conveyance belts 302b and 308, the feeding operation is started again, and the subsequent sheet is separated and fed. The

  By providing such sheet feeding devices 302 and 303, the sheet feeding devices 302 and 303 can be selected at any time according to the sheet to be inserted and fed. The sheet feeding may be performed alternately by the two sheet feeding apparatuses 302 and 303, or one of them may be used continuously.

  In the finisher 1006, the sheets conveyed from the sheet conveying path 301 are sequentially stacked and aligned. Although a detailed description of the operation is omitted, here, the controller 120 of the printer main body 1001 and the finisher control unit 132 communicate with each other to obtain the optimum conditions based on information such as the size, number of sheets, and type of sheets.

  The finisher 1006 can select various processing methods such as binding with a stapling device (not shown) for each bundle to be bound, or only stacking sheets without binding. .

  Next, 10 body texts are created by the printer main body 1001, and a sheet insertion device 1003 is attached to the front and back covers printed in advance, and a bundle for inserting a partition sheet is inserted between the fifth and sixth sheets of the text. A case of creating will be described.

  In this embodiment, the cassette 100 of the printer main body 1001 accommodates a sheet for creating a text. In addition, the upper sheet feeding device 302 of the sheet insertion device 1003 accommodates a partition sheet, and the lower sheet feeding device 303 accommodates a sheet bundle in which preprinted front and back cover sheets are alternately stacked. ing.

  Since the control unit 120 of the printer main body 1001 controls not only the control of the printer alone but also the control of the entire system, when the bundle creation signal is input, this bundle creation signal is used as the control unit 120 of the printer main body 1001. Receive. Note that this bundle creation signal input method may be performed from the above-described operation unit shown in FIG. 8 provided in the printer main body 1001 or by a remote computer or the like.

  When a bundle creation signal is input, the control unit 120 transmits information about sheets such as the number of sheets in one bundle and sheet insertion timing to the control unit 131 of the sheet insertion apparatus 1003 and the control unit 132 of the finisher. Based on this information, the sheet insertion apparatus 1003 and the finisher 1006 start operation preparation.

  That is, in the sheet insertion device 1003, the partition sheet S 7, which is the seventh sheet, is separated and fed from the upper feeding device 302, passes through the roller 317, and then reaches a stop position before reaching the merging conveyance path 301. stand by. The lower sheet feeding device 303 separates and feeds the cover sheet S1, which is the first sheet, passes through the sensor 315, and waits at a stop position before reaching the merged conveyance path 301.

  Next, when such preparation is completed, first, the cover sheet S1 of the sheet insertion apparatus 1003 is conveyed from the feeding standby position. At the same time, the printer body 1001 separates and feeds the body sheets S2 to S6 at equal intervals. Is done. After that, a time equivalent to the time when the partition sheet S7 is inserted, that is, one sheet is conveyed, is separated, and then the sheets S8 to S12 are separated and fed.

  Then, after the two sheet intervals corresponding to the back cover S13 and the second cover S14 are separated, the second body text sheets S15 to S19 are separated and fed. Yes. As described above, image formation is performed in a state where the interval between the sheets to be inserted is spaced.

  On the other hand, the cover sheet S1 waiting in the sheet insertion apparatus starts to move from the feeding standby position before the sheet S2 is discharged from the printer main body 1001, and is conveyed at a predetermined speed V1. Further, the conveyance roller 321 near the conveyance junction 320 in the sheet insertion device 1003 is increased to the conveyance speed V1 when the cover sheet S1 is conveyed.

  When the rear end of the cover sheet S1 passes through the conveyance roller 321, the conveyance speed of the printer main body 1001 and the sheet insertion device 1003, that is, the paper discharge speed V0 of the printer main body 1001, is reduced to prepare for the transfer of the sheet S2.

  Thereafter, the sheets S2 to S6 on which image formation has been performed pass through the paper discharge sensor 121, and after a predetermined time, are conveyed into the sheet insertion device 1003. After the sheet trailing edge has passed through the paper discharge roller 119, the conveyance is performed. The roller 321 is increased from the image forming speed V0 to a predetermined conveying speed V1. As a result, the sheets S2 to S6 are accelerated and conveyed in the sheet inserting device.

  The increase in the sheet conveyance speed is completed before the trailing edge of the sheet S6 reaches the junction point 320. Further, after the rear end of the sheet S6 passes through the junction point 320, the partition sheet S7 that is separated and fed from the upper sheet feeding device 302 and is waiting at the stop position is conveyed at the conveyance speed V1. As a result, the partition sheet S7 is inserted between the sheet S6 and the sheet S8 discharged from the printer main body 1001 next.

  In this way, the sheet that has passed through the junction 320 of the sheet conveyance path 301 is conveyed at the conveyance speed V1. Note that when the leading edge of the conveyed sheet passes the paper discharge sensor 319 of the sheet inserting device 1003, the sheet is again decelerated to a conveying speed V0 equivalent to the delivery speed of the printer main body 1001 and the sheet inserting device 1003, and the finisher 1006 Delivered.

  Next, the sheet S12 conveyed from the printer main body 1001 starts to accelerate at the acceleration point where the trailing edge has passed through the paper discharge roller 119, and increases from the conveying speed V0 to V1. On the other hand, the back cover S13 stopped at the stop position starts to be transported at the transport speed V1 at a timing such that the sheet interval becomes a predetermined interval.

  Since the rear end of the back cover S13 is obstructed and suction cannot be started unless the back cover S13 is transported, the next bundle of cover sheets S14 cannot be started. Therefore, after the transport of the back cover S13 is started, a predetermined suction is performed. Conveyance is started over time.

  In this embodiment, since the conveyance speed is fast, it is possible to create a waiting time and maintain a sheet interval while ensuring a sufficient suction time. Since the standby time is obtained in this way, even if an unexpected problem occurs during separation and feeding and a delay occurs in sheet conveyance, the delay can be absorbed within the standby time.

  Further, by increasing the conveyance speed from V0 to V1, the time from the trailing edge of the preceding sheet to the leading edge of the succeeding sheet can be lengthened, so that collision between sheets that is likely to occur at the time of merging can be avoided. .

  In this embodiment, the separation and feeding method of the printer main body 1001 is the retard method, and the separation and feeding method of the sheet inserting apparatus 1003 is the air separation method, but the separation method is not limited.

1 is a schematic configuration diagram of a printer that is an example of an image forming apparatus including a sheet feeding apparatus according to a first embodiment of the present invention. FIG. 3 is a control block diagram of a paper deck connected to the printer main body of the printer. The figure which shows the structure of the upper sheet accommodating part provided in the said paper deck. The figure which shows the structure of the lower sheet | seat accommodating part provided in the said paper deck. The figure which shows the sheet | seat floating upper limit provided in the said lower sheet | seat accommodating part, and the minimum which can detect the sheet | seat of a minimum sensor. The figure which shows the logic in the standby state of the said sheet floating upper limit sensor and a sheet floating upper limit sensor. FIG. 3 is a control block diagram of a printer main body and a paper deck of the printer. FIG. 3 is a diagram illustrating a configuration of an operation unit provided in the printer main body. The figure which shows the operation screen of the said operation part. The figure which shows the relationship between the basic weight of the sheet | seat with which the ROM of the control part of the said paper deck is equipped, and the rotation speed of a fan. The figure which shows the detail of the screen which inputs the sheet conditions of the said operation part. The figure explaining the paper surface control of the normal uppermost sheet in the said lower sheet accommodating part. The figure explaining the paper surface control of the uppermost sheet which is not normal in the said lower sheet accommodating part. On the operation screen of the operation unit, (a) is a screen displaying that the sheet conditions set on the operation screen may be different from the sheets stacked on the sheet tray, (b) is a fan or the like The figure showing the screen which displays that there is abnormality in. The figure showing the relationship between the fan fan PWM value by the said sheet conditions, and a sheet | seat tray movement amount. The figure which shows the warning alert | report displayed on the operation screen of the said operation part. The figure showing the relationship between the sheet basic weight by the said fan fan PWM value, and a sheet tray movement amount. 6 is a flowchart for explaining processing before a sheet feeding operation in the paper deck is started. FIG. 5 is a schematic configuration diagram of a printer that is an example of an image forming apparatus including a sheet feeding device according to a second embodiment of the present invention. The figure which shows the structure of the conventional sheet feeding apparatus. FIG. 10 is a first diagram illustrating a sheet feeding operation of the conventional sheet feeding apparatus. FIG. 9 is a second diagram illustrating a sheet feeding operation of the conventional sheet feeding apparatus. FIG. 10 is a third diagram illustrating a sheet feeding operation of the conventional sheet feeding apparatus. FIG. 10 is a fourth diagram illustrating a sheet feeding operation of the conventional sheet feeding apparatus. FIG. 10 is a diagram illustrating another configuration of a conventional sheet feeding apparatus. FIG. 10 is a diagram illustrating another configuration of a conventional sheet feeding apparatus.

Explanation of symbols

105 Sheet tray 107 Lower sheet separating and feeding device 120 Controller 151 Separating nozzle 152 Separating nozzle 160 Encoder 202A Upper sheet separating and feeding device 203 Operation unit 212 Material manual setting button 213 Material automatic setting button 300 Control unit 305 Sheet tray 607 Sheet floating lower limit Sensor 608 Sheet floating upper limit sensor 609 Rolling fan 610 Rolling fan duct 1000 Printer 1001 Printer main body 1002 Paper deck 1005 Image forming unit 2206 Operation unit F151 Rolling fan

Claims (8)

A sheet tray that can be raised and lowered, an air blowing unit that has a fan that blows air onto the sheets stacked on the sheet tray, and a suction conveyance mechanism that sucks and conveys the uppermost sheet of the rolled sheets A position detection unit that detects a position of the uppermost sheet of the sheets stacked on the sheet tray that has been rolled by the air blowing, and when the sheet is rolled by the air blowing, the position detection unit In a sheet feeding apparatus that controls to lower the sheet tray based on detection of the uppermost sheet by:
An elevation detection unit for detecting elevation of the sheet tray;
An input unit for inputting sheet information corresponding to the sheets stacked on the sheet tray;
With
When the air blowing unit blows air according to the air blowing condition based on the sheet information input from the input unit, the position detecting unit is at a position where the uppermost sheet can be fed. When the lift detection unit detects the rise of the sheet tray, the sheet information input by the input unit is determined to be different from the sheets stacked on the sheet tray. Sheet feeding device.   2. The apparatus according to claim 1, wherein when it is determined that the sheet information input by the input unit is different from the sheets stacked on the sheet tray, the fact that the sheet information is different is notified. Sheet feeding device. A rotation speed control unit that controls the rotation speed of the fan according to the sheet information input by the input unit;
The rotation number control unit rotates the fan at a rotation number corresponding to the sheet information input by the input unit, and when the elevation detection unit detects the rise of the sheet tray, the rotation number of the fan is set. 3. The sheet feeding apparatus according to claim 1, wherein the sheet feeding device is controlled to increase. A table showing the relationship between the sheet type, the rotational speed of the fan, and the amount of movement of the sheet tray from the sheet feeding standby position;
After the rotation speed of the fan is increased, when the lift detection unit detects the lowering of the sheet tray, the rotation speed of the fan after the increase and the movement of the sheet tray from the sheet feeding standby position are increased. 4. The sheet feeding apparatus according to claim 3, wherein the sheet information placed on the sheet tray is determined based on the amount and the table.   The said input part is provided with the display part which displays the determined said sheet information, and the manual input part which inputs the said sheet information displayed on the said display part manually. Sheet feeding device.   The sheet feeding apparatus according to claim 4, wherein the input unit includes an automatic input unit that automatically inputs the determined sheet information.   The sheet feeding device according to claim 4, wherein an abnormality is notified when the sheet tray does not descend even when the number of rotations of the fan is increased.   An image forming apparatus comprising: the sheet feeding device according to claim 1; and an image forming unit that forms an image on a sheet fed from the sheet feeding device. .

Images