JP4739084B2 - Sheet feeding apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet feeding apparatus that feeds sheets one by one from a stacked sheet, and an image forming apparatus including the sheet feeding apparatus.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer, in order to transfer a toner image formed on a photoconductor onto a sheet at a transfer position, a sheet cut to a predetermined size is transferred to the transfer position. A sheet feeding device for feeding sheets one by one is provided.

  As this sheet feeding device, a configuration is disclosed in which air is blown by a separation fan from one end side in the conveyance direction of the sheets stacked in the storage box, the sheets are floated, and the floated sheets are attracted to the conveyance belt and conveyed. (See Patent Document 1).

  However, the floating amount of the sheet varies depending on the material (thickness and weight). In view of this, a configuration has been proposed in which the lifting and lowering of the sheet table on which the sheets are stacked is controlled so that the floating position of the sheet floated by air blowing is positioned within a predetermined range. For example, it is determined by the position detection means whether or not the floating position of the floated sheet is within a predetermined range, and when it is out of the predetermined range, the seat base is moved up and down so that the floated sheet is predetermined. The structure controlled so that it may be located in the range is disclosed (refer patent document 2).

  Or the structure which controls the rotation speed of a isolation | separation fan is proposed so that a sheet | seat may become the optimal floating amount irrespective of a material. That is, when the sheet is thin or light, the separation fan is controlled to be low (slow), and when the sheet is thick or heavy, the separation fan is controlled to be high (fast). To do. Specifically, for example, the distance from the belt surface of the conveyor belt to the lifted sheet is recognized by a distance measuring sensor, and the rotation speed of the separation fan is controlled based on this distance to control the amount of air blown out. A configuration is disclosed (see Patent Document 3).

  Also, by inputting the material (thickness and weight) of the sheets stacked on the sheet table from the operation unit of the image forming apparatus, the air discharge amount is uniquely determined according to the input sheet material. Some have been proposed to control.

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

  However, in the technique described in Patent Document 2, even if the material (thickness and weight) of the sheet is different, the sheet is positioned within a predetermined range by raising and lowering the sheet base, but the sheet within the predetermined range It is not possible to determine whether or not is in an optimal whispering state. Here, every time the material (thickness or weight) of the sheets stacked on the sheet table is changed, as disclosed in Patent Document 3, in order to make the sheet to be optimally rolled regardless of the material, It is conceivable to change the rotation speed of the separation fan. However, even if the separation fan is set to the appropriate number of air blows for each sheet material, the separation fan is not suitable due to variations in the fan itself, changes in fan characteristics over time, or voltage drops due to bundled wires. May not be obtained stably. In this case, for example, when the sheet is a thin or light material, the rotation speed of the separation fan rotates faster than the target, the sheet is not stable, and jam, skew, misalignment, scratch, break In some cases, problems such as dirt may occur. Also, if the sheet is thick or heavy, the rotation speed of the separation fan will rotate slower than the target, and appropriate air will not flow between the sheets, causing problems such as double sheet feeding. There is.

  In the configuration in which the sheet material (thickness and weight) is input from the operation unit of the image forming apparatus, the sheet material (thickness and weight) input from the operation unit and the material of the sheet actually loaded on the sheet table May be different. In this case, the rotation speed of the separation fan becomes an inappropriate value, and as described above, problems such as sheet double feeding, skew feeding, misalignment, scratches, breakage, and dirt may occur.

  Therefore, an object of the present invention is to set the rotation speed so that the fan has an optimal air flow regardless of variations in the fan itself or changes in fan characteristics over time, and to stabilize the fan at the optimal rotation speed. .

In order to achieve the above object, a typical configuration of the present invention includes a tray that is capable of supporting a plurality of sheets and that can be raised and lowered, and a sheet is wound toward an end portion of the sheet supported by the tray. An air blowing section for blowing air for the above, a sheet blowing fan provided in the air blowing section, a rotation speed detecting means for detecting the rotation speed of the sheet blowing fan, a lifting operation of the tray, and the sheet blowing fan A sheet feeding device that separates and feeds the sheets one by one, wherein a rotation speed of the sheet fan detected by the rotation speed detection means is set in advance. as will be within a range of values, said sheet having an adjustment mode for adjusting the rotational speed of the loosening fan, there is the tray at the bottom position of the lower in elevation range of the tray A lower position detecting means for taking out the sheet and a sheet presence / absence detecting means for detecting the presence / absence of a sheet supported on the tray. When the sheet presence / absence detecting means detects that there is no sheet, the lower position detecting means is supported by the tray. The control unit is configured to lower the tray until it is detected by the lower position detection unit when the control unit transitions to the adjustment mode. When the sheet presence / absence detecting means is in a no sheet state with the tray in the lower position, an operation of adjusting the rotation speed of the sheet winding fan is started .

  According to the present invention, it is possible to adjust the rotation speed so that a necessary air volume of the fan can be obtained by providing the adjustment mode for adjusting the rotation speed of the fan. For this reason, the rotational speed can be set so that the blower fan has an optimum air volume regardless of variations in the fans themselves or changes in fan characteristics over time. In addition, the fan can be stabilized at an optimum rotational speed.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in the following embodiments should be appropriately changed according to the configuration of the apparatus to which the present invention is applied and various conditions. Therefore, unless specifically stated otherwise, the scope of the present invention is not intended to be limited thereto.

(Description of image forming apparatus)
First, a schematic configuration of the image forming apparatus shown in FIG. 1 will be described. FIG. 1 is a schematic cross-sectional view illustrating a schematic configuration of an image forming apparatus having a sheet feeding device.

  In FIG. 1, reference numeral 1 denotes an image forming apparatus. The image forming apparatus 1 includes a printer main body 1000 and a scanner 2000 disposed on the upper surface of the printer main body 1000. Further, the image forming apparatus 1 includes a sheet feeding device 3000 that feeds sheets to the printer main body 1000. The sheet feeding device 3000 includes an air separation and feeding mechanism as a sheet separation and feeding unit in order to perform stable separation and feeding for various types of sheets. The sheet feeding device 3000 will be described in detail later.

  First, the image forming apparatus 1 will be described in detail. Here, the scanner 2000 that reads a document includes a scanning optical system light source 201, a platen glass 202, a document pressure plate 203 that opens and closes, a lens 204, a light receiving element (photoelectric conversion) 205, an image processing unit 206, a memory unit 208, and the like. . The memory unit 208 is for storing the image processing signal processed by the image processing unit 206.

  When the original is read, the original placed on the platen glass 202 is read by irradiating light with the scanning optical system light source 201. Then, the read document 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 an image forming unit. Note that the 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 control unit 130.

  The printer main body 1000 includes a sheet conveying unit 1004 that conveys a sheet fed by the sheet feeding device 3000 to the image forming unit 1005, a control unit 130 for controlling the printer 1000, and the like.

  The sheet conveying unit 1004 includes a registration roller unit having a pre-registration roller pair 122 and a registration roller pair 122. The sheet fed from the sheet feeding device 3000 is guided by a sheet conveyance path 121 constituted by a guide plate, and after passing through the pre-registration roller pair 121, is guided to the registration roller pair 122. Thereafter, the sheet is once abutted against the registration roller pair 122, and the skew that occurs during sheet feeding and conveyance is corrected, and then conveyed to the image forming unit 1005.

  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. At the time of image formation, the 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 112 that rotates in the clockwise direction in FIG. As a result, a latent image is formed on the photosensitive drum 112. Thereafter, the latent image formed on the photosensitive drum 112 is visualized as a toner image by the developing device 114. It is possible to change the irradiation position of the laser beam through a laser writing position control circuit by a control signal from the control unit 130, and form a latent image in the longitudinal direction on the photosensitive drum 112, that is, a so-called main scanning direction. The position can be changed.

  The toner image on the photosensitive drum 112 is transferred to a sheet by the transfer charger 115 in the transfer unit 112b. Further, the sheet on which the toner image is transferred is electrostatically separated from the photosensitive drum 112 by the separation charger 116 and is conveyed to the fixing device 118 by the conveyance belt 117 to fix the toner image. The sheet on which the toner image is fixed is discharged out of the apparatus by a discharge roller 119. In addition, a discharge sensor 120 is provided in the conveyance path between the fixing device 118 and the discharge roller 119 so that passage of the sheet there can be detected.

  In this embodiment, the printer main body 1000 and the scanner 2000 are separate from each other, but the printer main body 1000 and the scanner 2000 may be integrated. The printer main body 1000 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. Further, in the scanner 2000, if an automatic document feeder 250 as shown by a two-dot chain line is installed instead of the pressure plate 203, the document can be automatically read.

(Description of sheet feeding device)
Next, the sheet feeding device 3000 in the image forming apparatus 1 shown in FIG. 1 will be described.

  The sheet feeding device 3000 includes a sheet feeding unit 331 on the lower side and a sheet feeding unit 322 on the upper side. Each of the sheet feeding units 331 and 332 includes sheet storage units 301 and 311 that can store a plurality of sheets S, respectively. In each of the sheet storage portions 301 and 311, there are trays 302 and 312 that can be moved up and down to stack the stored sheets S, and a rear end regulating plate 303 that regulates the rear end of the sheet S in the conveyance direction (arrow A direction). Each is provided. The trailing edge regulating plate 303 is movable according to the size in the conveying direction of the sheet S, and regulates the trailing edge in the conveying direction of the sheet so that the leading edge in the conveying direction of the sheet is aligned with the leading edge side in the conveying direction of the sheet storage unit 302. is doing. The sheet feeding units 331 and 332 have the same configuration, but the rear end regulating plate on the sheet feeding unit 332 side is not illustrated.

  Here, with reference to FIG. 2, a sheet separation and feeding unit (air separation and feeding mechanism) in the sheet feeding apparatus will be described. FIG. 2 is an enlarged view of a main part showing a sheet separating and feeding unit in the sheet feeding apparatus shown in FIG.

  In the sheet separating and feeding unit 304, the sheets in the sheet storage unit 301 are rotated near the upper portion of the stacked sheets S by blowing the air from the firing nozzle 151, which is the air blowing port, as the blowing fan F 151 rotates as a pre-feeding operation. Start whispering. When a feeding start signal is transmitted from the controller 300, a negative pressure (suction force) is generated in the suction belt 305 by the suction fan F150, and suction of the sheet is started. After a predetermined suction time from the start of suction, only the topmost sheet S1 of the stacked sheets S is attracted to the suction belt 305. After a predetermined time, rotation of the suction belt 305 is started by the suction belt motor M102 with the sheet S1 adsorbed, and the sheet S1 is conveyed in the direction of arrow A. When the leading edge of the sheet reaches the belt pulley, the leading edge of the sheet is released from the suction force by the suction fan F150, and is separated from the suction belt 305 and transferred to the drawing roller pair 10. 2 illustrates a configuration in which a separation fan F152 that blows out air for separating the leading end portion of the sheet from the suction belt 305 from the separation nozzle 152 is illustrated. When the leading edge of the sheet S1 reaches the drawing roller pair 10, the negative pressure by the suction fan F150 is released, so that the sheet is released from the suction force to the suction belt 305 and is transported only by the transport force of the pulling roller pair 10. . When the feeding start signal is transmitted again from the control unit 300 after the trailing edge of the sheet has come out of the suction belt unit, the feeding operation is started, and the subsequent sheet S2 is separated and fed.

  Here, as a pre-feeding operation, the fan F151 is operated before the feeding start signal is transmitted. However, after the feeding start signal is transmitted, the fan F151 is controlled to operate. It doesn't matter.

  Although only the sheet separation / feed unit 304 on the sheet storage unit 301 side has been described here, a sheet separation / feed unit 314 is similarly provided on the sheet storage unit 311 side, and the same separation / feed is performed. Is called.

  Further, as shown in FIG. 3, the drawing motors M10 and M20 are connected to the drawing roller pairs 10 and 20, respectively. Corresponding transport motors M11, M12, M13, M14, M15, M16, M21, M22, and M23 are connected to the transport roller pairs 11, 12, 13, 14, 15, 16, 21, 22, and 23, respectively. Yes. The sheet feeding device can drive each roller pair independently.

  In FIG. 3, reference numerals M5 and M205 denote lifter motors as lifter driving means for raising and lowering the trays 302 and 312, and moving the trays 302 and 312 in the sheet feeding units 331 and 332 up and down. Reference numerals M102 and M202 denote suction belt motors for rotationally driving the suction belts in the sheet feeding units 331 and 332, respectively. F150 and F250 are suction fans for sucking sheets to the belts in the sheet feeding units 331 and 332, respectively. F151 and F251 are sheet rolling fans in the sheet feeding units 331 and 332, respectively. F152 and F252 are separation fans in the sheet feeding units 331 and 332, respectively. The operation of these operation units is controlled by the control unit 300 as control means.

  In FIG. 3, reference numeral 604 denotes a rotation speed detection sensor serving as a rotation speed detection means, which detects the rotation speed of the fan. Reference numeral 605 denotes a tray lower position detection sensor serving as a lower position detecting unit, which detects the lower position of the tray. This lower position is a position where the trays 302 and 312 are lowered to the maximum during normal operation. Reference numeral 606 denotes a sheet presence / absence detection sensor serving as a sheet presence / absence detection unit, which detects the presence / absence of sheets stacked on the trays 302 and 312. Reference numeral 607 denotes a sheet floating lower limit sensor, and reference numeral 608 denotes a sheet floating upper limit sensor, which is a sensor for detecting the position of the sheet floating with the air from the rolling fan F151. A sheet loading position detection sensor 609 is provided in the middle of the raising / lowering range of the tray and stops at a position higher than the lower position. And based on the information from these various sensors, the control part 300 controls operation | movement of each operation | movement part mentioned above.

  Note that sheet information such as the paper size, paper type, and basis weight of the sheets stored in the respective sheet storage units 301 and 311 can be set from the operation unit of the image forming apparatus.

(Description of sheet insertion device)
Next, a schematic configuration of the image forming apparatus shown in FIG. 5 will be described. FIG. 5 is a schematic cross-sectional view illustrating a schematic configuration of an image forming apparatus having a sheet feeding device. In the image forming apparatus shown in FIG. 5, members having the same functions as those in the image forming apparatus shown in FIG.

  In FIG. 5, reference numeral 1 denotes an image forming apparatus. The image forming apparatus 1 includes a printer main body 1000 and a scanner 2000 disposed on the upper surface of the printer main body 1000. The image forming apparatus 1 shown in FIG. 5 includes a sheet insertion device 4000 as a sheet feeding device that is connected to the sheet discharge side of the printer main body 1000 and feeds sheets. Further, the image forming apparatus 1 includes a finisher 5000 as a sheet processing device on the sheet discharge side of the sheet insertion device 4000.

  In the image forming apparatus 1 shown in FIG. 5, the sheet S discharged from the printer main body 1000 is guided to the sheet conveyance unit 430 of the sheet insertion device 4000. The sheet insertion device 4000 includes a sheet feeding unit 331 on the lower side and a sheet feeding unit 332 on the upper side. The sheet conveying unit 430 is connected to a merging unit 333 from the sheet feeding units 331 and 332. The configuration of the sheet feeding units 331 and 332 of the sheet insertion device 4000 is the same as the configuration of the sheet feeding units 331 and 332 of the sheet feeding device 3000 described above. Are denoted by the same reference numerals, and the description thereof is incorporated. The sheet feeding units 331 and 332 of the sheet inserting device 4000 accommodate sheets such as slip sheets, front cover, back cover, and partition paper of a sheet bundle, sheets on which images have been formed, and the like. The sheets separated one by one in each of the sheet feeding units 331 and 332 are sequentially finished so as to be inserted between the sheets conveyed from the printer main body 1000 at the merging unit 333 in the middle of the sheet conveying unit 430. It is conveyed to 1006.

  As described above, since the sheet feeding units 331 and 332 have the same mechanism, a necessary feeding unit is selected at any time according to the sheets stored in the respective feeding units, and the sheets can be fed. it can. Further, the sheet feeding units 331 and 332 may alternately perform sheet feeding, or one of them may be used continuously.

  The finisher 5000 sequentially stacks and aligns the sheets conveyed through the sheet insertion device 4000. Although a detailed description of the operation is omitted, here, the control unit 130 of the printer main body 1000 and the control unit 131 of the finisher 5000 communicate to obtain the optimum condition based on information such as the size, number of sheets, and type of sheets. . In the finisher 5000, it is possible to select various processing methods, such as performing binding processing with a stapling device (not shown) for each bundle to be bound, or performing only stacking of sheets without performing binding processing. .

  Next, a case where a sheet bundle is created by the image forming apparatus 1 shown in FIG. 5 will be described. Here, a case where a sheet bundle composed of 13 sheets S1 to S13 is created will be described as an example. That is, ten text sheets S2 to S6 and S8 to S12 are created by the printer main body, attached with a front cover S1 and a back cover S13 printed in advance by a sheet insertion device, and further, a fifth sheet S6 for text A sheet bundle in which the partition sheet S7 is inserted between the sixth sheet S8 is created.

  The printer main body 1000 shown in FIG. 5 includes two sheet feeding units 1002 and 1003 below. The sheet feeding units 1002 and 1003 have the same configuration. In the sheet feeding units 1002 and 1003, the sheets stored in the sheet storage units 100 and 104 are selectively fed out by the pickup rollers 101 and 105, and are fed by the feed rollers 102 and 106 and the retard rollers 103 and 107. Each sheet is separated and conveyed to the sheet conveying unit 1004.

  The sheet storage units 100 and 104 of the printer main body 1000 store sheets for creating a text. The upper sheet storage unit 311 of the sheet insertion device 4000 stores partition sheets, and the lower sheet storage unit 301 stores a bundle of sheets on which front and back cover sheets are alternately stacked. .

  Since the control unit 130 of the printer main body 1000 controls not only the control of the printer alone but also the entire image forming apparatus, the control unit 130 of the printer main body 1000 first receives the signal for creating the sheet bundle. To do. The signal input method may be performed from the operation unit of the image forming apparatus 1 or by a computer or the like at a remote location.

  When a signal for creating a sheet bundle is input, the control unit 130 transmits information about the sheet such as the number of sheets in one bundle and sheet insertion timing to the control unit 300 of the sheet insertion device 4000 and the control unit 131 of the finisher 5000. In each apparatus, preparation for operation is started.

  Specifically, in the sheet insertion device 4000, the partition sheet S7 is separated and fed from the upper sheet feeding unit 332, and waits at a standby position before reaching the joining unit 333 of the sheet conveying unit 430. The cover sheet S1 is separated and fed from the lower sheet feeding unit 331, and waits at a standby position before reaching the joining unit of the sheet conveying unit 430.

  When the operation preparation is completed in each apparatus, first, the first cover sheet S1 is conveyed from the standby position in the sheet insertion apparatus 4000, and at the same time, in the printer main body 1000, the text sheets S2 to S6 (from the first sheet to the fifth sheet). (Up to eyes) are fed at regular intervals. After that, a time equivalent to the time when the partition sheet S7 of the sheet insertion device 4000 is inserted, that is, one sheet is conveyed, is left, and then the main body sheet S8 to S12 (sixth sheet) To 10th sheet) are fed separately. Then, after the back cover S13 of the first copy and the sheet interval of two covers of the second copy are provided, the second copy of the body sheet is printed on the printer main body from the first to the fifth copy. Until it is separated.

  As described above, image formation is performed in a state where the interval between the sheets to be inserted by the sheet insertion apparatus is spaced. The sheets S2 to S6 on which image formation has been performed are transported in the sheet insertion device 4000 at a transport speed that is faster than the transport speed in the printer body. That is, in the sheet insertion device 4000, the leading edge of each sheet passes through the discharge sensor 120 and is conveyed into the sheet insertion device 4000. After the trailing edge of each sheet passes through the discharge roller 119, the sheet insertion device 4000 has an image forming speed. The speed is increased to a second transport speed V1 that is faster than the first transport speed V0.

  Further, the cover sheet S1 waiting in the sheet insertion device 4000 starts to move from the standby position before the first body sheet S2 is discharged from the printer main body 1000, and starts to be transported at the second transport speed V1. Has been. The conveyance roller 13 in the vicinity of the conveyance junction 333 in the sheet insertion device 4000 is accelerated to the second conveyance speed V1 when the cover sheet S1 is conveyed. When the rear end of the cover sheet S1 passes through the transport roller 13, the sheet inserting device 4000 decelerates to the first transport speed V0 that is the discharge speed of the printer main body 1000 in preparation for the delivery of the body sheet from the printer main body 1000. Is done.

  As described above, the text sheets S <b> 2 to S <b> 6 are accelerated and conveyed in the sheet inserting device 4000. Note that the increase in the sheet conveyance speed ends before the trailing end of the text sheet reaches the conveyance path junction 333. For this reason, the partition sheet S7 that has been waiting at the standby position in the sheet insertion device 4000 is started to be transported at the second transport speed V1 after the rear end of the text sheet S6 has passed the transport junction 333, The sheet is inserted between S6 and the sheet S8 discharged from the printer main body. Thus, the sheet that has passed through the junction 333 in the sheet insertion device 4000 is conveyed at the second conveyance speed V1. However, the sheet is conveyed at the second conveyance speed in the sheet insertion device 4000, but when the leading edge passes through the discharge sensor 319 of the sheet insertion device 4000, the sheet is decelerated to the first conveyance speed V0 and the finisher 5000. Is passed on. In other words, the sheet inserting device 4000 is decelerated to the first conveying speed V0 that is the image forming speed in preparation for the delivery of the sheet from the printer main body 1000 again.

  After conveyance of the partition sheet S7, conveyance of the text sheets S8 to S12 in the sheet insertion apparatus is performed in the same manner as the above-described sheets S2 to S6. Then, the back cover S13 waiting at the standby position in the sheet insertion device 4000 is transported at the second transport speed V1 in the same manner as the partition sheet S7 after the rear end of the text sheet S12 passes through the transport junction 333. Be started. The back cover S13 is separated and fed from the sheet storage unit 301 after the cover S1 is conveyed and before the sheet S12 is sent to the sheet insertion device 4000, and waits at a standby position before the junction. Yes.

  Thereafter, when the next sheet bundle is processed in the same manner, the rear end of the back cover S13 is obstructed by the sheet separating and feeding unit unless the cover S14 of the next bundle is after the back cover S13 is conveyed. Of the front cover S14 cannot be started. For this reason, after the conveyance of the back cover S13 is started, the suction conveyance of the cover S14 is started after a time (suction time) in which the rear end of the back cover S13 is separated from the belt.

(Explanation of control block)
FIG. 4 is a block diagram showing the configuration of the control unit 130 in the printer main body 1000 and the control unit 300 of the sheet feeding apparatus 3000 shown in FIG. The configurations of the control unit 130 in the printer main body 1000 and the control unit 300 of the sheet insertion device 4000 shown in FIG. 5 are the same as the block diagram shown in FIG.

  The control unit 130 in the printer main body 1000 includes a CPU 211, ROM 212, RAM 213, communication interface (I / F) 214, input / output port 215, operation unit 216, image processing unit 206, and image memory unit 208.

  The CPU 211 performs basic control of the printer main body 1000, and a ROM 212 in which a control program is written, a work RAM 213 for performing processing, and an input / output port 215 are connected by an address bus and a data bus. A part of the RAM 213 is a backup RAM in which data is not erased even when the power is turned off. The input / output port 215 is connected to various load devices such as a motor and a clutch controlled by the printer main body 1000 and an input device such as a sensor for detecting the position of the sheet.

  The CPU 211 sequentially performs input / output control via the input / output port 215 in accordance with the contents of the control program stored in the ROM 212, and executes image forming processing. An operation unit 216 is connected to the CPU 211, and the CPU 211 controls a display unit and a key input unit of the operation unit 216. The user instructs the CPU 211 to switch the image forming operation mode and display through the key input unit. The CPU 211 operates the display unit of the operation unit 216 with respect to the operation state of the printer main body 1000 and the operation mode set by key input. Is displayed. Further, an image processing unit 206 that processes a signal converted into an electric signal by the image sensor unit (light receiving element) 205 and an image memory unit 208 that stores the processed image are connected to the CPU 211.

  Note that the control unit 300 of the sheet feeding device 3000 performs the operation described with reference to FIG. 1, the CPU 351, the ROM 352, the RAM 353, the communication interface (I / F) 354, the input / output port 355, and the operation unit 356. It consists of The CPU 351 inputs detection results from a floating upper limit sensor 608 and a floating lower limit sensor 607, which will be described later, and a rotation speed detection sensor 604, a tray lower position detection sensor 605, and a sheet presence / absence detection sensor 606, via the input / output port 355. Then, based on the detection result, the CPU 351 outputs a drive command to lifter motors M5 and M205, the separation fans F151 and F251 and the suction fans F150 and F250, which will be described later. Note that the levitation upper limit sensor 608 is disposed above the levitation lower limit sensor 607. Further, a distance measuring sensor (not shown) capable of measuring a distance may be used instead of the ascent upper limit sensor and the ascent lower limit sensor.

(Explanation of operation unit)
FIG. 6 is a schematic diagram showing the configuration of the operation unit in the image forming apparatus of the present embodiment.

  In FIG. 6, reference numeral 221 denotes a display unit, which displays various messages such as the operation state of the apparatus and work instructions to the user, work procedures, and the like. Further, the surface of the display unit 221 is configured by a touch panel, and acts as a selection key by touching the surface. Reference numeral 222 denotes a numeric keypad for inputting numbers. Reference numeral 223 denotes a start key. When this key is pressed, a copying operation is started. Reference numeral 224 denotes an application mode selection key for inputting sheet conditions such as sheet surface material, basis weight, and surface smoothness.

  For example, the material of the sheet accommodated in the sheet feeding apparatus 3000 is selected from the display unit (operation screen) 225 as shown in FIG. Here, thin paper 231, plain paper 232, thick paper 233, and thickest opening 234 are illustrated as specific materials of the sheet. Further, the material may be automatically set (235 in the figure). Further, the sheet conditions such as the sheet surface material, basis weight, and surface smoothness may be finely set (236 in the figure).

  The control unit 300 of the sheet feeding device 3000 sets the rotation speed of the fan F151, F251 according to the setting of the sheet material (basis weight, surface property, etc.) set in the display unit 225 shown in FIG. A table is provided for changing the rotational speed to obtain the rotational speed. When the setting is not made, the normal plain paper 232 is set. Further, it may be possible to finely set other than the setting items of the display unit shown in FIG.

(Explanation of sheet separation and feeding section)
Next, the configuration of the sheet separating / feeding unit (air separating / feeding mechanism) included in the above-described sheet feeding unit will be described.

  FIG. 9 is a cross-sectional configuration diagram of a peripheral portion of the sheet separating and feeding unit and the sheet storage unit in the sheet feeding unit. 2 illustrates the configuration in which the suction fan F150 is disposed in the suction belt 305, the configuration may be such that the suction fan F150 is disposed outside the suction belt 305 as illustrated in FIG.

  9 illustrates the sheet separating and feeding unit 304 of the sheet feeding unit 331 in the sheet feeding device 3000 illustrated in FIG. 1, but the sheet feeding unit 332 and the sheet insertion in the sheet feeding device 3000 are illustrated. The sheet feeding unit in the apparatus 4000 has the same configuration. Further, the sheet feeding units 1002 and 1003 in the printer main body 1000 shown in FIG. 5 exemplify a retard type separation feeding mechanism, but the invention is not limited to this, and an air separation feeding mechanism using an adsorption conveyance belt is used. It doesn't matter.

  In FIG. 9, a tray 302 that moves up and down a sheet bundle on which sheets S are stacked can be moved up and down by driving a lifter motor M5 via a pulley 603. An encoder is attached to the lifter motor M5, and it is possible to know the drive amount of the lifter motor M5, that is, the movement amount of the tray 302 by this encoder. The moving direction of the tray 302 can be known from the rotation direction of the encoder or the control signal of the motor.

  In order to detect the lower position of the tray 302, a tray lower position detection sensor 605 is disposed. On the other hand, a sheet presence / absence detection sensor 606, a sheet floating lower limit sensor 607, and a sheet floating upper limit sensor 608 for detecting the height of the sheet are disposed above the sheet separating and feeding unit 304. The sheet presence / absence detection sensor 606 detects a sheet with a flag sensor, and the sheet floating lower limit sensor 607 and the sheet floating upper limit sensor 608 detect a sheet with an optical sensor. The sheet presence / absence detection sensor 606 is disposed below the sheet lift lower limit sensor 607 and the sheet lift upper limit sensor 608. That is, when the sheet S stacked on the tray 302 rises to the feeding start position, the sheet presence / absence detection sensor 606 moves the upper surface of the sheet bundle S before the sheet floating lower limit sensor 607 and the sheet floating upper limit sensor 608. It is configured so that it can be detected.

  Further, the sheet lift lower limit sensor 607 and the sheet lift upper limit sensor 608 are sensors for detecting the position of the sheet lifted by the air from the separation fan F151 described later. The sensitivity of the sheet floating lower limit sensor 607 is adjusted so that a floating sheet positioned below the sheet floating upper limit sensor 608 can be detected. As a result, it is possible to detect whether the floated sheet is positioned within a predetermined range using the sheet floating lower limit sensor 607 and the sheet floating upper limit sensor 608. The relationship between the detection state of the sheet floating lower limit sensor 607 and the sheet floating upper limit sensor 608 and the sheet feeding state will be described later.

  Further, a fan F151 and a fan fan duct 610 are installed for the purpose of rolling the sheet S stored in the sheet storage unit 301 prior to the feeding operation. By supplying the wind pressure in the discharge direction generated by rotating the fan F151 to the vicinity of the uppermost sheet of the sheet bundle S by the fan fan duct 610, a plurality of sheets are fed at a time during the sheet feeding operation. (Multifeed) is prevented.

  Further, a suction belt 305, a suction fan F150, and a suction fan duct 613 are installed as a sheet feeding mechanism. The wind pressure in the suction direction generated by rotating the suction fan F150 is applied to the suction belt 305 through the suction fan duct 613 so that the uppermost sheet of the sheet bundle S is adsorbed. The sheet adsorbed by the suction belt 305 is conveyed to the feeding retry sensor 620 and the drawing roller pair 10 side when the suction belt 305 is rotated in the illustrated direction.

  FIG. 9 shows a state where the sheet is adsorbed by the suction fan F150. When the sheet floating lower limit sensor 607 and the sheet floating upper limit sensor 608 detect the sheet floating position, the sheet floating position is detected while the rolling fan F151 is operated. That is, as shown in FIG. 10, while the suction fan F <b> 151 is operated without operating the suction fan F <b> 150, the elevation of the tray 302 is controlled based on the sheet lifting lower limit sensor 607 and the sheet lifting upper limit sensor 608. The Note that the standby position of the sheet bundle S when both the suction fan F150 and the separation fan F151 are not in operation may be the on-edge (detection position) of the sheet lifting lower limit sensor 607 or the on-edge of the sheet presence / absence detection sensor 606. Absent.

  In FIG. 9, the presence / absence of a sheet on the tray 302 is detected by the sheet presence / absence detection sensor 606, but the on-edge (a dotted line position in FIG. 9) of the sheet presence / absence detection sensor 606 is an air outlet of the fan duct 610. It is arranged below the firing nozzle 151. Further, when the separation fan F151 is not in operation, the stop position (standby position) of the tray 302 is the on-edge of the sheet presence / absence detection sensor 606. A sheet detection sensor 609 is disposed in the middle of the raising / lowering range of the tray 302. The sheet loading position detection sensor 609 outputs a signal for detecting and stopping the tray 302 while the tray 302 is lowered and moved to the lower position when the sheet presence / absence detection sensor 606 detects the absence of a sheet. Is. In this way, the tray 302 is stopped without lowering the tray to the lower position so that the sheet can be loaded, thereby improving the workability of loading the sheet. Further, when sheets for one pack (500 sheets) are loaded on the tray 302, the sheet loading position detection sensor 609 controls the tray 302 to move down until it detects the uppermost surface of the loaded sheet. The top surface position is always constant. As a result, the sheets can always be loaded at the same height, and workability is improved.

  FIG. 11A and FIG. 11B explain the logic of the sheet floating lower limit sensor 607 and the sheet floating upper limit sensor 608. If the standby position of the sheet bundle S when both the suction fan F150 and the separation fan F151 are in the non-operating state is the on-edge of the sheet lifting lower limit sensor 607, that state is the standby state of the sheet bundle S. When the fan F151 is driven in this state, several sheets above the sheet bundle S are rolled, the uppermost sheet of the sheet bundle S floats, and the uppermost sheet that floats is between the sheet floating lower limit sensor 607 and the sheet floating upper limit sensor 608. The raising and lowering of the tray 302 is controlled to enter.

  The sheet detectable lower limits of the sheet floating lower limit sensor 607 and the sheet floating upper limit sensor 608 are as shown in FIG. 9 and 10, the sheet floating lower limit sensor 607 and the sheet floating upper limit sensor 608 are arranged in the sheet feeding direction, but accurate detection is possible by arranging them in the direction perpendicular to the sheet feeding direction. It becomes possible.

  In addition, by inputting sheet conditions such as the surface material, basis weight, and surface smoothness of the sheets stacked on the tray 302 from the operation screen 225 shown in FIG. 7, the air volume of the fan F 151 is optimized. The rotational speed of the fan is set so as to be the rotational speed. Of course, when the rolling fan F151 is operated under the input sheet conditions, the uppermost sheet of the sheet bundle S is located between the sheet floating lower limit sensor 607 and the sheet floating upper limit sensor 608 without performing the raising / lowering operation of the tray 302. Move to. Alternatively, the uppermost sheet of the sheet bundle S moves above the sheet floating upper limit sensor 608. As described above, the sheet floating lower limit sensor 607 and the sheet floating upper limit sensor 608 can be used for the floating sheet even if the raising and lowering operation of the tray 302 is not performed when the rolling fan F151 operates at an optimum rotation speed corresponding to the material of the sheet. It is arrange | positioned in the position which can detect. As shown in FIG. 12, when the sheet condition set on the operation screen matches the sheet condition stacked on the tray 302, the tray 302 is finally controlled to be lowered by ΔL1.

(Adjustment mode of the fan)
Next, an adjustment mode for stabilizing the rotational speed of the blower fan F151 will be described with reference to FIGS. After turning on the power, or after a predetermined number of sheets are conveyed by the sheet feeding device 3000, or after a predetermined time has elapsed, control is performed so as to shift to the adjustment mode of the fan F151. Here, the predetermined number may be a preset number or may be a number input from the operation screen. When the job operation is continuing after the predetermined number of sheets are conveyed by the sheet feeding device 3000, control may be performed so as to shift to the adjustment mode of the fan F151 after the job ends or before the job starts. Absent. In the present embodiment, the number of the fan F151 is one, but it may be plural. Further, the suction fan F150 may be controlled so as to shift to the adjustment mode. Note that the number of sheets fed by the sheet feeding device 3000 is counted by a control unit 300 (CPU 351) (not shown) such as a counter (not shown) that counts at the rising edge or falling edge of the signal output of the retry sensor 620. ) Is provided.

  In FIG. 13, when an adjustment mode transition signal is detected after power is turned on, after a predetermined number of sheets are conveyed by the sheet feeding device 3000, or after a predetermined time has elapsed, the lowering operation of the tray 302 by the lifter motor M5 (lifter driving means) is performed. It is started (FIG. 13A). When the tray 302 is detected by the lower position detection sensor 605, the lifter motor M5 is controlled to stop, and the tray 302 stops (see FIG. 13B). In this state, if a sheet is not detected by the sheet presence / absence detection sensor 606, the fan F151 is driven, and after a predetermined time has elapsed, the rotation speed adjustment of the fan is started (see FIG. 13C). Here, in order for the rotation speed adjustment by the blowing fan F151 to be performed normally, there is an obstacle (shielding object) in front of the air blowing port (the blowing nozzle 151) by the blowing fan F151 (on the extended line in the air blowing direction). must not. For example, when the sheet bundle S stacked on the tray 302 is on the extension line of the air blowing port of the whirling nozzle 151 by the whirling fan F151, the air flow path of the whirling fan F151 is blocked, so that the normal rotation speed and air volume Can't get wind pressure. Therefore, the tray 302 is controlled to be lowered by the lifter motor M5. When the tray 302 is detected by the lower position detection sensor 605, the lifter motor M5 stops. If no sheet is detected by the sheet presence / absence detection sensor 606 in this state, it can be determined that there is no obstacle in front of the whispering nozzle 151 (on the extended line of the air outlet), and therefore the rotational speed adjustment of the whirling fan F151 is adjusted. It can be carried out.

  The rotation speed adjustment of the fan F151 will be described with reference to FIG. In a fan that can monitor the rotational speed, a target value is required to adjust the rotational speed of the fan. From the characteristics of the fan, it is known that when a fan is rotated with a predetermined PWM (Pulse Width Modulation) setting, a predetermined wind pressure is obtained at the same time as a predetermined rotation speed (FG) is output. For example, when a certain fan is operated at a PWM 100% setting, a rotational speed (FG) output of 600 Hz is made as the rotational speed output, and at the same time, 1000 Pa (Pascal) is obtained as the wind pressure. Assuming that the wind pressure required for adjusting the fan speed is 840 Pa, the target value range is set so that the fan speed is 500 Hz as the target value, 502 Hz as the target upper limit value, and 498 Hz as the target lower limit value. In other words, after a predetermined time (preset time) has elapsed after the start of the fan operation, the PWM value after the normal adjustment of the fan is set to 90% by controlling the fan speed to be adjusted, for example. Become. As described above, the reason for waiting for the elapse of the predetermined time after the start of the fan operation is waiting for the rotation speed of the fan to stabilize. After the rotational speed of the fan is stabilized, the rotational speed is adjusted, and control is performed so as to change the PWM value of the fan so that the rotational speed (FG) of the fan becomes a predetermined value. As a method for adjusting the rotation speed of the fan, a method in which the PWM value is decreased every predetermined value after the fan is rotated at a PWM value of 100%, or a value obtained by multiplying a coefficient that is a difference between the target value and the actual rotation speed is used. A method for increasing or decreasing the PWM value can be used. Further, when adjusting the rotation speed of the fan, the fan may be controlled to rotate at a predetermined PWM setting value instead of rotating at the PWM value of 100%.

  In addition, referring to FIG. 8, a state in which the driving PWM value of the winding fan is changed according to the seat condition after the rotation speed adjustment of the winding fan is normally completed will be described. FIG. 8 is an example, and the coefficient according to the sheet condition can be changed. As described above, a state in which a value of 90% is obtained as the PWM value for obtaining the necessary wind pressure 840 Pa as the adjustment value of the rolling fan is the wind pressure at which the thickest sheet can be rolled. That is, when the thickest sheet is selected, the PWM value of the fan is set to 90% × 1.0 = 90%. When thick paper is selected, the PWM value of the fan is set to 90% × 0.75 = 67.5%. When plain paper is selected, the PWM value of the fan is set to 90% × 0.5 = 45%. When thin paper is selected, the PWM value of the fan is set to 90% × 0.25 = 22.5%.

  A case where the rotation speed adjustment of a plurality of fans is simultaneously performed will be briefly described. As shown in FIG. 16, the plurality of fans are configured in a cascade connection, and a stronger wind pressure can be obtained by connecting a plurality of fans. For example, when a certain fan is operated at a PWM 100% setting, a rotation speed (FG) output of 220 Hz is made as a rotation speed output, and at the same time, a wind pressure of 300 Pa (Pascal) is obtained. It is assumed that the wind pressure necessary for adjusting the rotational speed of the fan is 840 Pa when four fans are connected in cascade. Then, the target values of the rotation speeds of the four fans, and the upper limit value and the lower limit value thereof are set as follows. That is, the target value range is set so that the rotation speed of the fan F101 is 182 Hz as the target value, 184 Hz as the target upper limit value, and 180 Hz as the target lower limit value. The target value range is set so that the rotation speed of the fan F102 is 171 Hz as the target value, 173 Hz as the target upper limit value, and 169 Hz as the target lower limit value. The target value range is set so that the rotation speed of the fan F103 is 181 Hz as the target value, 183 Hz as the target upper limit value, and 179 Hz as the target lower limit value. The target value range is set so that the rotation speed of the fan F104 is 162 Hz as the target value, 164 Hz as the target upper limit value, and 160 Hz as the target lower limit value. That is, control is performed so that the rotation speed of each fan is adjusted after a predetermined time has elapsed after the start of the fan operation. As a result, for example, the PWM value after normal adjustment of the fan is 92% for the fan F101, 87% for the fan F102, 91% for the fan F103, and 82% for the fan F104. Here, the case where the number of fans is four has been described, but the present invention is not limited to this, and the number of fans connected in cascade may be any number.

  In addition, referring to FIG. 8, a state in which the driving PWM value of the winding fan is changed according to the seat condition after the rotation speed adjustment of the winding fan is normally completed will be described. As described above, as the PWM values for obtaining the necessary wind pressure 840 Pa as the adjustment value of the fan, the fan F101 is 92%, the fan F102 is 87%, the fan F103 is 91%, and the fan F104 is 82%. This is the wind pressure at which the thickest sheet can be rolled. That is, when the thickest opening is selected, the PWM value of the fan F101 is 92% × 1.0 = 92%, the PWM value of the fan F102 is 87% × 1.0 = 87%, and the PWM value of the fan F103 is 91% × 1.0 = 91%, and the PWM value of the fan F104 is set to 82% × 1.0 = 82%. When thick paper is selected, the PWM value of the fan F101 is 92% × 0.75 = 69%, the PWM value of the fan F102 is 87% × 0.75 = 65.25%, and the PWM value of the fan F103 is 91% × 0.75 = 68.25%, and the PWM value of the fan F104 is set to 82% × 0.75 = 61.5%. When plain paper is selected, the PWM value of the fan F101 is 92% × 0.5 = 46%, the PWM value of the fan F102 is 87% × 0.5 = 43.5%, and the PWM value of the fan F103. Is set to 91% × 0.5 = 45.5%, and the PWM value of the fan F104 is set to 82% × 0.5 = 41%. When thin paper is selected, the PWM value of the fan F101 is 92% × 0.25 = 23%, the PWM value of the fan F102 is 87% × 0.25 = 21.75%, and the PWM value of the fan F103 is 91% × 0.25 = 22.75%, and the PWM value of the fan F104 is set to 82% × 0.25 = 20.5%.

  Next, a case where the rotation speed of the fan cannot be adjusted will be described with reference to FIG. When the adjustment mode transition signal is detected after the power is turned on, after a predetermined number of sheets are conveyed by the sheet feeding device 3000, or after a predetermined time has elapsed, the lowering operation of the tray 302 by the lifter motor M5 is started (FIG. 14A). reference). When the tray 302 is detected by the lower position detection sensor 605, the lifter motor M5 is controlled to stop, and the tray 302 stops (see FIG. 14B). In this state, when a sheet is detected by the sheet presence / absence detection sensor 606 (see FIG. 14C), control is performed to display a warning as shown in FIG. 19 on the operation screen. From this state, when the sheet storage unit is opened, several sheets stacked on the tray 302 are removed, and the sheet storage unit is closed again, the lowering operation of the tray 302 is started again. When the tray 302 is detected by the lower position detection sensor 605, the lifter motor M5 is controlled to stop, and the tray 302 stops. In this state, if a sheet is not detected by the sheet presence / absence detection sensor 606, the winding fan F151 is driven, and after a predetermined time has elapsed, the rotation speed adjustment of the fan is started.

  Further, regarding the adjustment mode for stabilizing the fan rotation speed described above, the adjustment mode may be selected from the operation screen as shown in FIG.

  Next, the operation after starting the air volume adjustment of the blower fan F151 will be described with reference to FIG. When the air flow adjustment of the fan F151 starts, if it falls within the target value range as shown in FIG. 15 within a predetermined time, the fan air flow adjustment is finished and the fan operation is stopped. To be controlled. At the same time, the lifter motor M5 is controlled to raise the tray 302. When the upper surface of the sheets stacked on the tray 302 is detected by the flying lower limit sensor 607, the lifter motor M5 is controlled to stop.

  On the other hand, if it does not fall within the target value range as shown in FIG. 15 within a predetermined time after the start of adjusting the air volume of the fan F151, the rotation speed adjustment of the fan F151 is finished and the fan Control is performed to stop the operation of F151. Subsequently, as shown in FIG. 20, control is performed to display a warning that the rotation speed adjustment of the fan has failed. Here, the display is such that the rotation speed of the fan is adjusted again, but an error display may be used. Note that the warning that the rotation speed adjustment has failed may be displayed earlier than the operation stop timing of the fan F151.

(Explanation of adjustment mode timing chart)
Next, the operation timing related to the adjustment mode will be described using the timing chart of FIG.

  The operation of the sheet feeding device 3000 and the operation of the separating fan F151 after the turning fan F151 enters the adjustment mode after turning on the power, passing a predetermined number of sheets by the sheet feeding device, or after a predetermined time has elapsed. Explained.

  22 are all H (high) active (detected at H, activated at H, activated at H), but are active at L (detected at L, activated at L, valid at L). It does not matter.

  When the adjustment signal becomes H (becomes active) in order to enter the rotation speed adjustment mode of the fan F 151, the lowering operation of the lifter motor M 5 that raises and lowers the tray 302 is controlled. When the tray 302 reaches the lower position detection sensor 605, the lifter motor M5 is controlled to stop. When the lifter motor M5 is stopped, the state of the sheet presence / absence detection sensor 606 is checked next, and if the sheet absence state is detected, the winding fan F151 is controlled to be driven. After a predetermined time T1 has elapsed since the operation of the firing fan F151 is started, the rotation speed adjustment of the firing fan F151 is started. Control is performed so that the rotation speed of the fan is adjusted for a predetermined time (preset time) T2. When the rotation speed of the fan F151 falls within a predetermined target value within the predetermined time T2, the rotation speed adjustment of the fan F151 is finished and the operation of the fan F151 is stopped. Is done. Note that whether or not the rotational speed of the fan F151 falls within a predetermined target value range can be determined based on the state of the adjustment mode normal end signal. In FIG. 22, the rotation speed adjustment is finished after the H level of the adjustment mode normal end signal continues for time T4. However, the adjustment mode is activated when the adjustment mode normal end signal continues the H level for a predetermined number of times at a predetermined interval. You may control so that it may judge that it complete | finished normally. FIG. 22 shows a state in which the rotation speed adjustment is completed within the predetermined time T2. Subsequently, the tray 302 is controlled to rise, and when the presence / absence detection sensor 606 detects that there is a sheet, the lifter motor M5 is controlled to stop and the tray 302 stops. By doing so, a standby state is set, and preparations are made so that feeding can be started at any time in preparation for the feeding start signal. In FIG. 22, the start timing of raising the tray 302 may be anywhere from the adjustment mode end signal on to the fan drive signal off (T3). Moreover, although the timing of FIG. 22 is an example, the transition states indicated by the arrows may be simultaneous or delayed.

  Next, a case where the fan rotation speed adjustment mode is not changed will be described with reference to FIG. When the adjustment signal becomes H (becomes active) in order to enter the rotation speed adjustment mode of the fan F 151, the lowering operation of the lifter motor M 5 that raises and lowers the tray 302 is controlled. When the tray 302 reaches the lower position detection sensor 605, the lifter motor M5 is controlled to stop. When the lifter motor M5 is stopped, the state of the sheet presence / absence detection sensor 606 is checked next. If the sheet presence state is detected, the alarm display signal is controlled to be turned on, and the operation screen as shown in FIG. Controlled to display warnings.

  Next, how the rotation speed of the fan is adjusted after the above-described warning display is performed and a part of the upper part of the sheet stacked on the tray 302 is removed will be described with reference to the timing chart of FIG. In order to remove the sheets stacked on the tray 302, it is necessary to pull out the sheet storage unit itself from the apparatus main body or to store the sheet storage unit in the apparatus main body after removing the sheet. The operation is omitted. After a part of the upper part of the sheet stacked on the tray 302 is removed, when the sheet presence / absence detection sensor 606 detects that there is no sheet, the fan F151 is controlled to be driven. Control is performed so as to start the rotation speed adjustment of the whirling fan F151 after a predetermined time has elapsed since the operation of the whispering fan F151 has started. When the rotation speed of the fan F151 falls within a predetermined rotation speed range within a predetermined time, the rotation speed adjustment of the fan F151 is finished and the operation of the fan F151 is stopped. . Subsequently, the tray 302 is controlled to rise, and when the presence / absence detection sensor 606 detects that there is a sheet, the lifter motor M5 is controlled to stop and the tray 302 stops. By doing so, a standby state is set, and preparations are made so that feeding can be started at any time in preparation for the feeding start signal.

  Next, the case where the rotation speed adjustment of the fan has failed will be described with reference to FIG. When the adjustment signal becomes H (becomes active) in order to enter the rotation speed adjustment mode of the fan F 151, the lowering operation of the lifter motor M 5 that raises and lowers the tray 302 is controlled. When the tray 302 reaches the lower position detection sensor 605, the lifter motor M5 is controlled to stop. When the lifter motor M5 is stopped, the state of the sheet presence / absence detection sensor 606 is checked next, and if the sheet absence state is detected, the winding fan F151 is controlled to be driven. After a predetermined time T1 has elapsed since the operation of the firing fan F151 is started, the rotation speed adjustment of the firing fan F151 is started. Control is performed so that the rotation speed of the fan is adjusted for a predetermined time (preset time) T2. When the rotational speed of the fan F151 does not fall within the predetermined target range within the predetermined time T2, the rotation speed adjustment of the fan F151 is finished and the rotation speed adjustment fails as shown in FIG. It is controlled to display a warning to the effect. Thereafter, the operation of the fan F151 is controlled to stop.

  Although the sheet presence / absence detection sensor 606 has been described as a stop signal after the lifting operation of the tray 302 by the lifter motor M5, the floating lower limit detection sensor 607 or the floating upper limit sensor 608 may be used.

(Explanation of adjustment mode flowchart)
Next, operations related to the adjustment mode will be described using the flowchart of FIG.

  The operation of the sheet feeding device 3000 and the operation of the separating fan F151 after the turning fan F151 enters the adjustment mode after turning on the power, passing a predetermined number of sheets by the sheet feeding device, or after a predetermined time has elapsed. Explained.

  When entering the rotation speed adjustment mode of the fan F151, the lowering operation of the lifter motor M5 that controls the tray 302 starts (S101). When the tray 302 reaches the lower position detection sensor 605 (S102), the lifter motor M5 is controlled to stop. When the lifter motor M5 is stopped, the state of the sheet presence / absence detection sensor 606 is checked next (S103), and when the sheet presence state is detected, a warning as shown in FIG. 19 is displayed on the operation screen. (S116). In this state, when the sheet storage unit is opened, several sheets stacked on the tray 302 are removed, and the sheet storage unit is closed, a series of flows starts again from S101.

  On the other hand, looking at the state of the sheet presence / absence detection sensor 606 (S103), when the sheet absence state is detected, the fan F151 is controlled to be driven. In this case, when a plurality of rolling fans are connected in cascade, the plurality of fans are controlled to operate simultaneously (S104). After a predetermined time has elapsed since the operation of the whirling fan F151 was started (S105), control is performed so as to start adjusting the rotational speed of the whirling fan F151 (S106). If the rotation speed of the fan F151 does not fall within the predetermined target range within a predetermined time in S107 after the rotation speed adjustment of the fan F151 is started (S112), the rotation of the fan F151 is rotated. The number adjustment is finished and the operation of the blower fan F151 is controlled to be stopped (S113). Subsequently, as shown in FIG. 20, control is performed to display a warning that the rotation speed adjustment of the fan F151 has failed (S114). In FIG. 20, the display is such that the fan rotation speed adjustment is performed again, but an error display may be used. Note that a warning display indicating that the rotation speed adjustment has failed may be performed earlier than the operation stop timing of the blower fan F151.

  On the other hand, if the rotation speed of the fan F151 falls within the predetermined target value range within the predetermined time in S107 (S107), the rotation speed adjustment of the fan F151 is finished and the operation of the fan F151 is performed. Is controlled to stop (S108). Subsequently, the tray 302 is raised (S109), and when the presence / absence detection sensor 606 detects that there is a sheet (S110), the lifter motor M5 is controlled to stop, and the tray 302 stops (S111). By doing so, a standby state is set, and preparations are made so that feeding can be started at any time in preparation for the feeding start signal.

  As described above, it is possible to adjust the rotation speed so as to obtain the necessary fan wind pressure by providing the rotation speed adjustment mode of the fan. Thus, the rotational speed can be set so that the fan can have an optimum air volume (wind pressure) regardless of variations in the fan itself, changes in fan characteristics over time, or voltage drop due to bundled wires. Further, the rotation speed of the fan can be stabilized at the optimum rotation speed. In addition, due to the relationship between the fan speed and the fan wind pressure, even in a multiple connection configuration of multiple fans, it is possible to set an optimum wind pressure by setting a range of target values for adjusting the speed. it can.

  In the above-described embodiment, the tray 302 is lowered to the lower position in the rotation speed adjustment mode, and when it is determined that there is no sheet based on the detection of the sheet presence / absence detection sensor 606, the rotation speed adjustment of the fan F151 is adjusted. Although it started, it may be as follows. In the rotation speed adjustment mode, when the tray 302 is lowered and the sheet loading position detection sensor 609 detects the uppermost surface of the sheet bundle S supported by the tray 302, the rotation speed adjustment control is started. At this time, since the uppermost surface of the sheet bundle S is already positioned below the detection position of the sheet presence / absence detection sensor 606, it is not necessary to adjust the rotational speed based on the detection of the sheet presence / absence detection sensor 606. That is, when the sheet loading position detection sensor 609 detects the position of the uppermost surface of the sheet bundle S supported by the tray 302, the sheet bundle S is unrolled by the fan F151 in front of the air outlet of the separation nozzle 151. Not located. In this control, if the lower position detection sensor 605 detects the tray 302 before the tray 302 is lowered and the sheet loading position detection sensor 609 detects the uppermost surface of the sheet, the presence / absence of a sheet according to the above-described embodiment. Control based on detection by the detection sensor 606 is performed.

  Further, the rotation speed adjustment of the fan F151 may be started as follows. The elevation of the tray 203 is counted by a counter so that the position of the tray 203 in the height direction can be known. That is, the position in the height direction of the tray 203 can be known by the count number by using an encoder provided in the lifter motor M5 or a stepping motor as the lifter motor. That is, the count number is set to 0 at the lower position so that the count number increases as the tray 203 rises. Then, the tray 302 is lowered by a predetermined count number in the rotation speed adjustment mode. The count number at this time is a number until the sheet bundle S stacked on the tray 302 disappears from the front of the air blowing port of the firing nozzle 151 by the separation fan F151, and can be set in advance. In this case as well, if the lower position detection sensor 605 detects the tray 302 before counting the preset count, control based on the detection of the sheet presence / absence detection sensor 606 of the above-described embodiment is performed. Do.

  In the above-described embodiment, the configuration in which the sheet feeding device or the sheet inserting device includes two sheet feeding units having the air separation feeding mechanism is exemplified. However, the sheet feeding having the air separation feeding mechanism is exemplified. The number of parts is not limited to this, and may be set as needed.

  In the above-described embodiment, as a sheet feeding device having a sheet separation fan (air separation and feeding mechanism), a sheet feeding device and a sheet installed on the upstream side in the sheet conveying direction with respect to the image forming apparatus main body. The sheet insertion device installed on the downstream side in the conveyance direction is illustrated. However, the present invention is not limited to these, and is effective when applied to, for example, a sheet feeding apparatus provided integrally with the main body of the image forming apparatus.

  In the above-described embodiment, the sheet feeding device that separates and feeds the sheets to be recorded one by one is illustrated, but the present invention is not limited to this, and the sheets to be read are separated one by one. It is also effective when applied to a sheet feeding apparatus for feeding.

Schematic cross-sectional view showing a configuration in which the sheet feeding apparatus according to the present embodiment is arranged on the input side of the image forming apparatus Cross-sectional configuration diagram illustrating an example of a sheet separating and feeding unit of the sheet feeding apparatus according to the present embodiment Control block diagram of sheet feeding apparatus according to the present embodiment FIG. 2 is a block diagram illustrating the configuration of a control unit of a printer main body and a control unit of a sheet feeding apparatus according to the present embodiment. Schematic sectional view showing a configuration in which the sheet insertion apparatus according to the present embodiment is arranged on the output side of the image forming apparatus Schematic showing the configuration of the operation unit in the image forming apparatus of the present embodiment The figure which shows the screen which inputs the sheet condition on the operation screen Diagram showing coefficient for adjustment value for sheet condition Cross-sectional configuration diagram illustrating an example of a sheet separating and feeding unit of the sheet feeding apparatus according to the present embodiment The figure which shows the sheet | seat detection lower limit of a sheet levitation upper limit sensor and a sheet levitation lower limit sensor (A) The figure which shows the logic of the sheet levitation upper limit sensor and the sheet levitation lower limit sensor in a standby state, (b) The figure which shows the logic of the sheet levitation upper limit sensor and the sheet levitation lower limit sensor after the operation of the rolling fan Diagram showing top sheet surface control when normal The figure showing the case where the rotation speed of the fan can be adjusted A diagram showing the case where the fan speed cannot be adjusted A diagram showing the range of target values when adjusting the fan speed Schematic cross-sectional view showing the multiple connection configuration of multiple fans A figure showing how to select whether or not to adjust the air volume from the operation screen The figure showing the flowchart of the fan air volume adjustment which concerns on this Embodiment Diagram showing warning on operation screen before adjusting fan speed A diagram showing a warning on the operation screen when fan speed adjustment fails Diagram showing the operation after the fan speed adjustment has been completed successfully The figure showing the timing chart from fan speed adjustment start to normal end The figure showing the timing chart when the number of rotations of the fan is not adjusted The figure showing the timing chart from the start of rotation adjustment of the fan to the normal end after removing the sheet The figure showing the timing chart explaining the control after the rotation speed adjustment of a fan fails

Explanation of symbols

F150, F250 ... Suction fans F151, F251 ... Whisper fan (sheet fire fan)
M102, M202 ... Suction belt motor M5, M105 ... Lifter motor (lifter driving means)
S ... sheet 1 ... image forming apparatus 100, 104 ... sheet storage unit 130 ... control unit 131 ... control unit 151 ... firing nozzle (air blowing port)
225 ... Display section (operation screen)
300 ... Control unit (control means)
301, 311 ... sheet storage unit 302, 312 ... tray 303 ... rear end regulating plate 304, 314 ... sheet separation and feeding unit 305 ... suction belt 331, 332 ... sheet feeding unit 333 ... confluence unit 430 ... sheet conveying unit 604 ... Rotational speed detection sensor (Rotational speed detection means)
605 ... Tray lower position detection sensor (lower position detection means)
606 ... Sheet presence / absence detection sensor (sheet presence / absence detection means)
607 ... Sheet floating lower limit sensor 608 ... Sheet floating upper limit sensor 609 ... Sheet loading position detection sensor 610 ... Separation fan duct 613 ... Suction fan duct 620 ... Feed retry sensor 1000 ... Printer main body 1002, 1003 ... Sheet feeding unit 1004 ... Sheet Conveying unit 1005 ... Image forming unit 2000 ... Scanner 3000 ... Sheet feeding device 4000 ... Sheet insertion device (sheet feeding device)
5000 ... Finisher (sheet processing device)

Claims (13)

A tray that is capable of supporting a plurality of sheets and that can be moved up and down, an air spraying unit for spraying air toward the end of the sheet supported by the tray, and the air spraying unit A sheet rolling fan, a rotation speed detection unit that detects the rotation speed of the sheet rolling fan, and a control unit that controls the raising / lowering operation of the tray and the operation of the sheet rolling fan. A sheet feeding device for separating and feeding
An adjustment mode for adjusting the number of rotations of the seating fan so that the number of rotations of the sheeting fan detected by the number of rotation detection means falls within a preset target value range;
The sheet presence / absence detection means comprising: a lower position detection means for detecting the presence of the tray at the lowest lower position in the raising / lowering range of the tray; and a sheet presence / absence detection means for detecting the presence / absence of a sheet supported on the tray. When it is detected by the means that there is no sheet, the sheet supported by the tray is below a position where air is blown from the sheet blowing fan,
When the control means transitions to the adjustment mode, the control means lowers the tray until it is detected by the lower position detecting means, and the sheet presence / absence detecting means is in a no sheet state when the tray is at the lower position. The sheet feeding device is configured to start an operation of adjusting a rotation speed of the sheet rolling fan when the sheet feeding fan starts. A tray that is capable of supporting a plurality of sheets and that can be moved up and down, an air spraying unit for spraying air toward the end of the sheet supported by the tray, and the air spraying unit A sheet rolling fan, a rotation speed detection unit that detects the rotation speed of the sheet rolling fan, and a control unit that controls the raising / lowering operation of the tray and the operation of the sheet rolling fan. A sheet feeding device for separating and feeding
An adjustment mode for adjusting the number of rotations of the seating fan so that the number of rotations of the sheeting fan detected by the number of rotation detection means falls within a preset target value range;
A sheet loading position detection sensor for detecting the position of the uppermost surface of the sheet supported by the tray at an intermediate position in the raising and lowering range of the tray;
The sheet presence / absence detection means comprising: a lower position detection means for detecting the presence of the tray at the lowest lower position in the raising / lowering range of the tray; and a sheet presence / absence detection means for detecting the presence / absence of a sheet supported on the tray. When it is detected by the means that there is no sheet, the sheet supported by the tray is below a position where air is blown from the sheet blowing fan,
When the control unit shifts to the adjustment mode, when the tray is lowered and the tray is detected by the lower position detection unit before the uppermost surface of the sheet is detected by the sheet loading position detection sensor. The sheet feeding device starts an operation of adjusting the rotational speed of the sheet winding fan when it is detected by the sheet presence / absence detection means that there is no sheet. When the tray is detected by the lower position detecting means, if the presence / absence of the sheet is detected by the sheet presence / absence detecting means, the operation screen is not operated without adjusting the rotation speed of the sheet rolling fan. The sheet feeding apparatus according to claim 1 , wherein the sheet feeding apparatus is controlled to display a warning on the sheet. The sheet separation fan sheet feeding apparatus according to claim 1 or 2, characterized in that it is constituted by a plurality of fans. The sheet feeding apparatus according to claim 4 , wherein the number of rotations of the plurality of fans is adjusted simultaneously when the adjustment mode is entered. The sheet feeding device according to claim 4 or 5 , wherein a range of a target value for adjusting a rotation speed can be set for each of the plurality of fans. 3. The control according to claim 1, wherein, when the mode is changed to the adjustment mode, control is performed so that the rotation speed is adjusted after a preset time from the start of the operation of the seating fan. Sheet feeding device. After starting the operation of adjusting the rotational speed of the seating fan, when the rotational speed of the seating fan falls within the range of the target value, a signal indicating that the adjustment mode has ended normally is output. The sheet feeding device according to claim 1 , wherein the sheet feeding device is controlled. The sheet feeding device according to claim 1 , wherein the sheet feeding fan is controlled to adjust the rotation speed of the sheet rolling fan for a preset time. If the rotation speed of the seating fan does not fall within the target value within a preset time after starting the adjustment of the rotation speed, the operation of the seating fan is stopped and the operation screen is displayed. The sheet feeding device according to claim 9 , wherein the sheet feeding device is controlled to display a warning above. If the rotation speed of the seating fan falls within the target value within a preset time after starting the adjustment of the rotation speed, the operation of the seating fan is stopped, and the seat The sheet feeding device according to claim 9 , wherein the tray is raised until the presence / absence detecting unit detects that a sheet is present. 3. The sheet according to claim 1 , wherein the sheet is controlled to shift to an adjustment mode for adjusting the number of rotations of the sheet rolling fan after the power is turned on or after a predetermined number of sheets are fed. Feeding device. A sheet feeding apparatus according to any one of claims 1 to 12, the image forming apparatus characterized by having an image forming unit for forming an image on a sheet fed by said sheet feeding apparatus.

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