JP2017132587A - Sheet feeding device and image formation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably separate and float a sheet from a sheet bundle without excessively increasing an air capacity and air pressure of a floating air to be blown to a lateral face of the sheet bundle.SOLUTION: When feeding an uppermost sheet of a sheet bundle, a sheet feeding device has an abutment member 251 abut on a lateral face of the sheet bundle facing an air blowing port 212a of an air blowing part 212, raises the abutting abutment member 251 together with the air blowing part 212 and supplies separation air that is supplied from the air blowing port 212a to the lateral face of the sheet bundle, between sheets.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a sheet feeding device and an image forming system.

  A copier, a facsimile machine, a printer, and an image forming system having these functions are provided with a paper feed unit. Then, the sheets stacked and stored in the sheet feeding unit are separated and sent one by one, and the fed sheets are conveyed to the image forming unit to form an image.

  In general, as a system for separating and transporting sheets one by one, a transport device using a roller transport system paper feeding unit is widely used. The roller used in the roller transport system has a surface formed of an elastic body having a large friction coefficient such as rubber, and separates and transports the sheets one by one by the frictional force with the roller surface.

  On the other hand, in recent years, an electrophotographic image forming system has been used in the field of light printing such as POD (Print On Demand), and is required to be able to meet various needs regarding image quality and paper. In particular, for paper, gloss coated paper, high quality paper, follow-up paper, recycled paper, and the like may be used.

  In conventional roller transport paper feeders, the paper is transported by the frictional force between the paper and the roller surface, and gloss coated paper with a very smooth surface cannot provide sufficient frictional force to feed paper. Absent. In addition, for extra-printed paper and recycled paper, the release force (dusting powder) and paper dust adhering to the surface are transferred to the roller surface, reducing the frictional force and providing stable feeding over the long term. There is a problem that cannot be performed.

  As a method for dealing with such a problem, an air assist type paper feeding device has been proposed. This air-assist type paper feeding device blows air from the periphery toward the upper side of the paper bundle and stacks the paper on top of the paper stack. Float from the stack of paper and separate. Then, the separated uppermost sheet is conveyed one by one by a sheet feeding roller or the like.

  In addition, a paper feeding device is disclosed in which the height of the nozzle provided with the air outlet is raised following the paper that floats in order to continue to send air stably to the side edge of the paper that has floated further ( (See Patent Document 1 and Patent Document 2).

  Further, in the paper feeder disclosed in Patent Document 2, the nozzle (duct) is moved up and down by using the wind pressure from the fan that forms the airflow to be blown.

Japanese Patent No. 4135709 JP 2010-126296 A

In the air assist type paper feeding device, in principle, the air blown from the side of the sheet bundle enters the gap between the sheets, so that the sheets rise. However, if the paper is very thick, such as over 400 g / m ² , or if the edges are very clean and the sides of the paper bundle are smooth, the sprayed air will not be able to enter between the sheets. Unable to lift the paper.

  FIG. 11 is a schematic diagram illustrating a problem with cardboard. FIG. 11A is a diagram illustrating a state of a side surface of a sheet bundle in which thick sheets are stacked. In a normal thick sheet, a side surface of the stacked sheet bundle has irregularities, and a side surface of the sheet bundle has a wedge shape. As shown in FIG. 11B, when flying air is blown onto the side of such a bundle of sheets, the floating air enters the gaps between the sheets to form a thin air layer, and separates the adhered sheets. Can be lifted.

In general, if the amount of paper is about 40 to 300 g / m ² , the paper can be separated and floated by changing the air volume / air pressure of the flying air. However, even when the paper is very thick, for example, when the weight is 400 g / m ² or more, or thinner than this, the side surface of the paper bundle is not uneven and is very smooth when placed on the stacking unit. In this case, the paper cannot be separated and floated.

  FIG. 11C is a diagram illustrating a state where the sheet is very thick and the side surface of the sheet bundle is very smooth. In the case of such a sheet bundle, even if flying air is blown onto the side surface of the sheet bundle, there is no gap between the sheets, so that the floating air cannot enter between the sheets and the sheet cannot be lifted.

  The higher the wind pressure applied to the paper, the easier it will be to float the paper.However, in the configuration where the air flow is blown using a fan, there is a limit to the wind pressure, and the configuration using a pump other than the fan increases the size of the device, It is not realistic from the viewpoint of increasing energy consumption and cost.

  Further, in the configuration in which the nozzle is moved up and down using the wind pressure from the fan as described above, when the wind pressure is increased corresponding to heavy thick paper, the nozzle rises over the paper before the paper rises. As a result, there is a problem in that the air cannot be blown to an appropriate position and the paper cannot be lifted.

  The present invention has been made in view of the above circumstances, and can stably separate and float a sheet from a sheet bundle without excessively increasing the air volume / wind pressure of the flying air blown to the side surface of the sheet bundle. An object of the present invention is to provide a sheet feeding device capable of preventing sheet feeding defects.

  The above object of the present invention is achieved by the following means.

(1) a stacking unit that stacks a stack of sheets on which a plurality of sheets are stacked;
An air blowing portion capable of moving up and down, provided with an air blowing port facing the side surface of the stacked sheet stack;
A blower unit that sends air to the air blowing unit to form an air flow from the air blowing port toward a side surface of the sheet bundle;
A paper feeding unit that feeds the uppermost paper that is separated from the paper bundle by the airflow and floats;
An abutting member that moves up and down integrally with the air blowing portion;
With
When the paper is fed, the contact member is brought into contact with a side surface of the sheet bundle facing the air blowing port, and the abutting contact member is raised together with the air blowing unit;
Paper feeder.

(2) a switching mechanism that switches the contact member between a contact position that contacts the side surface of the sheet bundle and a retracted position that does not contact;
The contact member is switched from the retracted position to the contact position when the switch is raised by the switching mechanism, and is set to the retracted position except when the lift is performed.
The sheet feeding device according to (1) above.

(3) The contact member is switched to the contact position by the switching mechanism before the ascent starts.
The sheet feeding device according to (2) above.

(4) a switching mechanism that switches the contact member between a contact position that contacts the side surface of the sheet bundle and a retracted position that does not contact;
When the sheet stacked on the stacking unit is thick paper and is raised, the abutment member is switched from the retracted position to the contact position when the paper is raised, and other than the thick paper or when the paper is raised Is set at the retracted position,
The sheet feeding device according to (1) above.

(5) The switching mechanism switches the contact member to the contact position and the retracted position according to the presence or absence or increase or decrease of the wind pressure of the airflow formed by the air blowing unit.
The sheet feeding device according to any one of (2) to (4) above.

(6) The air blowing unit can be switched between a first wind pressure corresponding to thick paper and a second wind pressure lower than the first wind pressure corresponding to thin paper,
The supply according to (5), wherein the contact member is set to the contact position by the switching mechanism at the first wind pressure, and is set to the retracted position at the second wind pressure. Paper device.

(7) The stacking unit is provided with a side surface regulating unit that regulates an end portion in a width direction orthogonal to the sheet conveyance direction,
The friction coefficient with the sheet of the contact surface of the contact member is larger than the friction coefficient with the sheet of the sheet regulation surface of the side regulating part,
The sheet feeding device according to any one of (1) to (6) above.

  (8) The abutting member is disposed in the air flow from the air blowing port toward the side surface of the sheet bundle, and the projected area of the abutting member viewed from a direction perpendicular to the air blowing port. The sheet feeding device according to any one of (1) to (7), wherein is smaller than an area of the air outlet.

(9) The sheet feeding device according to any one of (1) to (8) above,
An image forming unit that forms an image on paper fed from the paper feeding device;
An image forming system.

  According to the present invention, when feeding paper, the abutting member is brought into contact with the side surface of the sheet bundle facing the air blowing port of the air blowing unit, and the abutting contacting member is raised together with the air blowing unit. Since the separation air sent from the air outlet to the side surface of the sheet bundle can be sent between the sheets, the sheet can be stably separated and floated from the sheet bundle, and a paper feed failure can be prevented.

1 is a cross-sectional view illustrating a main configuration of an image forming system according to an embodiment. It is a perspective view of a paper feed unit. FIG. 4 is an enlarged cross-sectional view of a main part of a paper feed unit. FIG. 4A is a cross-sectional view of the side regulating portion showing the state of the side regulating portion when the blower fan is stopped and FIG. 4B is operating. FIG. 5A is a perspective view of the contact mechanism, and FIG. 5B is a side view. It is a schematic diagram which shows the size and positional relationship of an air blowing port and a contact member seen from the direction perpendicular | vertical to an air blowing port. It is a timing chart which shows the operation | movement at the time of paper feeding. It is a figure which shows the state of the contact member 251 and the air blowing part in time t0-t1. It is a figure which shows the state of the contact member 251 and the air blowing part in the time t31-t32. It is a figure which shows the state of the contact member and air blowing part in time t32-t4. It is a schematic diagram which shows the state of the paper at the time of feeding thin paper. It is a timing chart which shows the operation at the time of paper feeding in a modification. It is a schematic diagram explaining the subject in cardboard. FIG. 6 is a schematic diagram illustrating a state of a sheet when a contact member is not used as a comparative example.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the description of the accompanying drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. In addition, the dimensional ratios in the drawings are exaggerated for convenience of explanation, and may be different from the actual ratios. In the drawing, the vertical direction is the Z direction, the front and back directions of the image forming system are the Y direction, and the direction orthogonal to these Y and Z directions is the X direction. In the following description, the X direction may be referred to as a paper transport direction, and the Y direction may be referred to as a paper width direction.

  FIG. 1 is a cross-sectional view showing the main configuration of an image forming system 10 according to this embodiment of the present invention. As shown in FIG. 1, the image forming system 10 includes an image forming apparatus 100 and a paper feeding apparatus 200. The image forming apparatus 100 includes a control unit 110, an image forming unit 120, an operation panel 130, an image reading unit 140, a paper transport unit 150, a fixing unit 160, and a main body paper feeding unit 170.

  The control unit 110 includes a CPU, a RAM, a ROM, and an HDD (all shown), and appropriately reads various programs stored in the ROM and the like, expands them on the RAM, and the CPU executes them. Implement various functions.

The operation panel 130 includes a touch panel in which a touch sensor is superimposed on a liquid crystal display, for example, and displays the state of the image forming apparatus 100 to the user and accepts a print instruction from the user. In addition, the user can input setting information of the paper S stored in the main body paper feeding unit 170 or a paper feeding device 200 described later from the operation panel 130. This paper setting information includes the paper thickness, the weight (g / m ² ), and the type (coated paper, special paper, etc.). The image reading unit 140 is disposed on the main body of the image forming apparatus 100 and includes an optical system including a mirror and a lens and a reading sensor such as a CCD. A document or ADF (not shown) placed on a platen glass is provided. The conveyed original is read and an image signal is output. The paper conveyance unit 150 includes a plurality of conveyance roller pairs and a drive motor (not shown), and conveys the paper fed from the paper feeding device 200 or the main body paper feeding unit 170 to the image forming unit 120 and the fixing unit 160. To do.

  The image forming unit 120 is, for example, an electrophotographic image forming unit, and includes a photosensitive drum, a band electrode, an exposure unit, a developing unit, a transfer unit, a cleaning unit, and the like. The electrostatic latent image formed on the photosensitive drum is developed by the developing unit to become a toner image. The sheet S conveyed from the main body sheet feeding unit 170 and the like is subjected to timing control by the registration roller 151, and is conveyed to the transfer unit in synchronization with the toner image. The sheet S on which the toner image is transferred by the transfer unit is conveyed to the fixing unit 160 on the downstream side, and the toner image is fixed on the sheet.

(Paper Feeder 200)
With reference to FIGS. 2 to 6, the configuration of the sheet feeding device 200 according to the present embodiment will be described. The paper feeding device 200 includes one or a plurality of air assist type paper feeding units 20.

  FIG. 2 is a perspective view of the paper feed unit 20, and FIG. 3 is an enlarged cross-sectional view of the main part of the paper feed unit 20. As shown in FIGS. 2 and 3, the paper feeding unit 20 includes a side regulating portion 21, a pre-registration roller 22, a tip blowing portion 23, an air suction paper feeding portion 24 (“paper feeding portion” in the present invention), and a contact mechanism. 25, a front end restricting plate 27, a rear end restricting plate 28, and a stacking portion 29.

  The stacking unit 29 is a plate-like member and can stack a plurality of sheets S. The four side surfaces of the stacked sheets S (hereinafter also referred to as “sheet bundle”) have a leading end restricting plate 27 at the leading end, a trailing end restricting plate 28 at the trailing end, and a pair of side restricting portions on both sides in the width direction. 21 is regulated. The leading edge regulating plate 27 is fixed to the housing of the paper feeding unit 20. The other side surface restricting portion 21 and the rear end restricting plate 28 can be moved according to the size of the paper loaded on the stacking portion 29. The stacking unit 29 can be moved up and down by a lifting drive motor (not shown), and the upper surface of the sheet bundle has a predetermined height in accordance with the detection output of the photoelectric sensor PS1 arranged so that the detection area has a predetermined height. It is controlled to become.

(Air suction paper feeding unit 24)
As shown in FIGS. 2 and 3, an air suction sheet feeding unit 24 is disposed above the downstream side (sheet leading end side) of the sheet bundle in the sheet conveyance direction. The air suction paper feeding unit 24 includes a suction fan 241, a paper transport belt 242, rollers 243, 244 and 245, a duct 246, and an actuator 247.

  Three paper transport belts 242 are arranged in parallel in the width direction, and these endless paper transport belts 242 are rotatably supported by a roller 243 connected to a drive motor (not shown) and small diameter rollers 244 and 245. Is done. The paper conveying belt 242 is provided with a large number of small-diameter through holes, and a duct 246 is disposed on the inside thereof. A suction port facing the paper transport belt 242 is provided at the lower part of the duct 246, and the suction fan 241 applies a negative pressure to the inside of the paper transport belt 242. The air sucked by the suction fan 241 is discharged to the rear side of the apparatus through the duct 246.

  The suction fan 241 always operates during image formation, and the air suction paper feeding unit 24 sucks the uppermost paper S that is lifted from the paper bundle by air blowing described later by the paper transport belt 242. When the sheet S is attracted to the surface of the sheet transport belt 242, the actuator 247 rotates about the rotation shaft 247a (clockwise direction in FIG. 3), and the photoelectric sensor PS2 outputs an ON signal in accordance with this rotation. In response to the ON signal, the control unit 110 activates the drive motor to rotate the paper transport belt 242. The sheet S adsorbed on the surface is conveyed downstream (X direction) in the sheet conveyance direction according to this rotation, and is fed toward the conveyance path of the image forming apparatus 100. The control unit 110 determines that the sheet has been normally conveyed by outputting an ON signal from the photoelectric sensor PS3 arranged on the downstream side of the sheet conveying belt 242, and drives the pre-registration roller 22 at a predetermined timing. Let it begin.

(Tip blowing part 23)
The tip blower 23 includes a blower fan 231 and a duct. In some cases, a plurality of sheets S may be lifted from the sheet bundle by air blowing, and at that time, a sheet other than the uppermost sheet adsorbed to the sheet conveying belt 242 is spread by the leading edge blower 23. Specifically, air is blown toward the upstream side in the paper transport direction from the blowout port 23a of the leading end air blower 23. As a result, even if a plurality of sheets S are adsorbed to the sheet conveying belt 242, the sheets S other than the uppermost one are separated and dropped.

(Side control part 21)
FIG. 4 is a cross-sectional view of the side regulating portion 21. The pair of side surface restricting portions 21 provided at both ends in the width direction of the sheet bundle have a symmetrical configuration. FIG. 4 shows only the right side regulating portion 21 when viewed from the upstream side in the paper conveyance direction.

  The side regulating part 21 includes a duct housing 210, a blower fan 211, an air blowing part (upper duct) 212, a lower duct 213, an upper surface regulating plate 219, and a contact mechanism 25, which are provided inside the side regulating part 21. It has been. Hereinafter, the air blowing portion 212 and the lower duct 213 are collectively referred to simply as a “duct”. This duct is surrounded by a duct housing 210. The lower duct 213 is fixed, but the upper air blowing part 212 can move up and down together with the contact mechanism 25. In the embodiment described below, the air blowing portion 212 is moved up and down depending on the presence or absence of wind pressure due to the operation of the blower fan 211, and the contact state of the contact mechanism 25 is changed.

  FIG. 4A is a diagram illustrating a state of the side regulating portion 21 when the blower fan 211 is stopped and FIG. 4B is activated.

  When the blower fan 211 (the “blowing part” in the present invention) is stopped, the air blowing part 212 has a lower end of the movable range inside the duct housing 210 (hereinafter referred to as “the air blowing part” in the present invention) as shown in FIG. It is simply called “bottom position”). When the blower fan 211 is operating, the air blowing portion 212 is raised to the upper end of the movable range (hereinafter simply referred to as “upper end position”) as shown in FIG. 4B due to the wind pressure generated by the blower fan 211. , Stay in that position. The upward airflow formed by the blower fan 211 is bent in the horizontal direction by the air blowing portion 212 and discharged from the air blowing port 212a. The air blowing port 212a faces the upper side surface of the sheet bundle placed on the stacking unit 29, and the air flow from the air blowing port 212a is blown to the upper side surface of the sheet bundle.

(Abutment mechanism 25)
Here, the contact mechanism 25 will be described with reference to FIG. FIG. 5A is a perspective view of the contact mechanism 25, and FIG. 5B is a side view. The contact mechanism 25 and the blower fan 211 function as a “switching mechanism” that switches the contact member 251 to the contact position or the retracted position. The contact position and the retracted position will be described later.

  The contact mechanism 25 includes a contact member 251, a support member 252, and a spring 253. The support member 252 includes a rotation shaft 252a, an arm 252b, and a wind receiving plate 252c. A contact member 251 is fixed to the distal end side of the arm 252b.

  It is preferable to form a high frictional force with the sheet S on the surface of the contact member 251. Therefore, the contact member 251 has a friction coefficient between the sheet bundle (sheet S) and the friction coefficient between the sheet bundle and the sheet regulating surface 21 s (see FIGS. 2 and 4) of the side regulating portion 21. It is also composed of a large material or shape. As a material of the contact member 251, solid rubber, foam rubber, cork pad, or flocked cloth can be used. The shape of the contact surface of the contact member 251 may be not only a flat surface but also a shape provided with unevenness. The sheet regulating surface 21s is a sheet metal having a flat surface.

  The rotation shaft 252 a of the support member 252 is rotatably fixed to the air blowing portion 212, and one end of the spring 253 is fixed to the air blowing portion 212. In the initial state indicated by the solid line in FIG. 5B, the support member 252 and the contact member 251 are pulled in the clockwise direction by the elastic force of the spring 253 (spring force), and the arm 252b hits the stopper 26. It has stopped in the state. This initial state corresponds to the retracted state shown in FIG. 4A, and the contact member 251 is located at the retracted position. In this retracted position, the contact member 251 does not contact the side surface of the sheet bundle nor the edge of the sheet S as will be described later.

  When the blower fan 211 is activated and an air flow is formed, the support member 252 and the contact member 251 rotate counterclockwise against the force of the spring by the wind pressure received by the wind receiving plate 252c. The state shown by the broken line in FIG. The state indicated by the broken line corresponds to the contact state shown in FIG. 4B, and at this time, the contact member 251 is located at the contact position. At this contact position, as will be described later, the contact member 251 contacts the side surface of the sheet bundle or the edge of the sheet S. The spring constant of the spring 253 is set so that F1> F2, where F1 is the wind pressure acting on the wind receiving plate 252c when the blower fan 211 is operating, and F2 is the elastic force of the spring 253. doing.

  FIG. 6 is a schematic diagram showing the size and positional relationship between the air blowing port 212a and the contact member 251 viewed from the direction (Y direction) perpendicular to the air blowing port 212a. As shown in the figure, the contact member 251 is disposed in the air flow that flows through the air outlet 212a. The projected area of the contact member 251 viewed from the direction perpendicular to the opening surface of the air blowing port 212a is sufficiently smaller than the opening area of the air blowing port 212a. For example, the air outlet 212a is 50 mm to 100 mm in both width and height, whereas the contact member 251 is several mm to 10 mm. Thus, since the contact member 251 is sufficiently smaller than the air outlet 212a, the air flow is not hindered. The contact member 251 may be disposed so that the surface of the contact member 251 contacts the side surface of the sheet bundle facing the air blowing port 212a at the contact position. In other words, the contact position may be disposed in the air flow path from the inside of the duct to the side surface of the sheet bundle, and the retracted position may be disposed outside the air flow path.

(Operation of the contact member 251 and the air blowing part 212)
Hereinafter, the operations of the contact member 251 and the air blowing part 212 will be described with reference to FIG. 7 and FIGS. 8A to 8C.

  FIG. 7 is a timing chart showing the operation during paper feeding. The timing chart in the figure shows the operation when feeding one sheet, and when feeding a plurality of sheets continuously, the operation shown in the figure is repeated a plurality of times.

  The control unit 110 operates the blower fan 211 at a predetermined timing (time t1) in response to an input of an image forming operation start signal (time t0). In response to the operation of the blower fan 211, an air flow is formed inside the duct.

  FIG. 8A is a diagram showing the state of the contact member 251 and the air blowing portion 212 at time t0 to t1. During this period, the contact member 251 is in the retracted position and does not contact the side surface of the sheet bundle. The air blowing part 212 is at the lower end position.

  Due to the wind pressure generated by the operation of the blower fan 211, the support member 252 rotates to move the contact member 251 to the contact position (time t2).

  The air blowing portion 212 starts to rise from time t31 a little after the contact member 251 reaches the contact position, and reaches the upper end position at time t32. In the period from time t31 to time t32, the contact member 251 also rises integrally with the air blowing portion 212, and the contact member 251 that has been in contact with the side surface of the sheet bundle before this time is Ascending with the edge of By appropriately setting the air volume (wind pressure) of the blower fan 211, the shape / mass of the air blowing part 212, the spring force (F2), the area / direction of the wind receiving plate 252c, etc., the operation as shown in FIG. Execute. That is, the abutting member 251 starts and completes movement immediately after the wind pressure is generated by the operation of the blower fan 211 of the abutting member 251, but the air blowing part 212 has a time difference and rises after a little later than this. Start (time t1-t32).

  FIG. 8B is a diagram showing the state of the contact member 251 and the air blowing portion 212 at times t31 to t32. As the abutting member 251 rises while sliding on the side surface of the sheet bundle, the end of the sheet S is slightly lifted upward by friction between the sheet S and the abutting member 251, and a gap is formed between the sheets. Since the air blown from the air blowing port 212a (hereinafter also referred to as “floating air”) can be fed into the gap between the sheets, the sheet S that is in close contact can be easily separated.

  The separated paper S is raised by the flying air formed by the blower fan 211. At this time, since the air blowing port 212a also rises, it is possible to stably feed air to an appropriate position according to the edge of the rising paper S.

  The uppermost sheet S that has floated is adsorbed to the surface of the sheet conveying belt 242. The photoelectric sensor PS2 is turned on by the adsorption of the paper S to the paper transport belt 242 (time t4).

  FIG. 8C is a diagram showing the state of the contact member 251 and the air blowing part 212 at times t32 to t4. An upper surface regulating plate 219 is disposed above the air blowing port 212a, and the upper surface regulating plate 219 contacts the upper surface edge of the uppermost sheet S, thereby preventing the sheet S from floating too much. Further, the upward force that the upper surface regulating plate 219 receives from the paper S assists the air blowing unit 212 to rise.

  At time t4, the control unit 110 receives the fact that the photoelectric sensor PS2 is turned on, stops the operation of the blower fan 211, and stops the supply of the floating air. As the floating air stops, the wind pressure acting on the air blowing portion 212 and the abutting member 251 disappears, so the air blowing portion 212 falls by its own weight and returns to the lower end position, and the abutting member 251 moves to the retracted position. Return to.

  In response to the turning on of the photoelectric sensor PS2, the control unit 110 starts driving the paper transport belt 242 at a predetermined timing (time t5).

  By the rotation of the sheet conveying belt 242, the adsorbed sheet S is conveyed toward the pre-registration roller 22 on the downstream side. When the sheet S exits the operating range (detection range) of the actuator 247, the photoelectric sensor PS2 is turned off (time t6), and the sheet feeding operation is completed due to the photoelectric sensor PS3 being turned off. The driving of the conveying belt 242 is stopped and the paper feeding operation is finished (time t7).

(effect)
FIG. 12 is a schematic diagram illustrating a state of a sheet when the contact member 251 is not used as a comparative example. The flying air cannot enter the gap between the sheets, and the sheets cannot be separated from the sheet bundle. In this case, as shown in FIG. 12, the sheet does not float and only the air blowing part 212 rises.

  On the other hand, in the present embodiment, the abutting member 251 abuts on the side surface of the sheet bundle before the air blowing part 212 rises, and the air blowing part 212 rises after the abutting. With this rise, for example, even if the paper is thick as shown in FIG. 11C, a gap is formed on the side surface of the paper bundle, and the floating air can be sent.

  As described above, in this embodiment, when the paper is fed, the contact member 251 is brought into contact with the side surface of the sheet bundle facing the air blowing port 212 a, and the contact member 251 that is in contact with the air blowing unit 212. By raising the paper, the paper can be properly separated and a stable paper feeding operation can be performed. In particular, in the present embodiment, air can be sent into a gap between sheets generated by the abutting member 251 being lifted while sliding, so that a chance to float the sheet can be created. Accordingly, it is possible to prevent poor feeding by stably separating and floating the sheet from the sheet bundle without excessively increasing the air volume / wind pressure of the flying air blown to the side surface of the sheet bundle.

  The contact member 251 has an effect of separating the sheet from the sheet bundle in the step of floating the sheet (until time t32 in FIG. 7), and is useful for separating and floating the sheet. However, when the sheet conveying belt 242 is driven to convey the sheet in the conveying direction (X direction), it acts as a sheet-passing resistance. Therefore, the sheet may be retracted after the completion of the sheet floating. desirable. For this reason, in the present embodiment, the contact member 251 is switched to the retracted position at a timing (time t4) before the driving of the paper transport belt (time t5).

(Modification)
For thick paper, it is difficult to lift the paper with only the floating air, so that the contact member 251 creates a trigger to assist the floating of the paper. However, since thin paper (for example, 40 to 64 g / m ² ) is light, in many cases, ascent support by the contact member 251 is not necessary. Further, since the rigidity of the thin paper is low, as shown in FIG. 9, the paper is bent by the contact of the contact member 251. Deformation such as buckling or wrinkling of the paper occurs, or conveyance failure due to this deformation occurs.

In the modification described below, the contact member 251 is brought into contact with the side surface of the sheet bundle only for thick paper (for example, 211 to 500 g / m ² ). FIG. 10 is a timing chart illustrating an operation at the time of paper feeding in the modified example. The blower fan 211 used in the modified example can switch the air volume between two levels (strong / weak). The “strong” air volume forms a first wind pressure corresponding to the thick paper, and the “weak” air volume forms a second wind pressure lower than the first wind pressure corresponding to the thin paper.

  When the wind pressure acting on the wind receiving plate 252c at the first wind pressure and the second wind pressure is F31 and F32, respectively, the relation of F31> F2> F32 is established as compared with the elastic force F2 of the spring 253. Is set to the spring constant of the spring 253. Note that F32 is higher than the wind pressure required to raise the air blowing portion 212.

  The control unit 110 reads the setting information of the paper stored in each paper feeding unit 20 from the HDD or the like, and determines whether the paper is thick paper or thin paper according to the setting information. For example, when the haze amount is equal to or greater than a predetermined value and it is determined that the paper is thick, the control unit 110 sets the air volume of the blower fan 211 to “strong” and sets the wind pressure acting on the wind receiving plate 252c to the first wind pressure (F31). ). On the other hand, when it is determined that the paper is thin (or other than thick paper), the air volume of the blower fan 211 is set to “weak”, and the wind pressure acting on the wind receiving plate 252c is set to the second wind pressure (F32).

  In the timing chart of FIG. 10, the positions of the floating air and the contact member 251 are indicated by a solid line for thick paper and by a broken line for thin paper. Other movements are the same for thick paper and thin paper.

  In cardboard, since the wind pressure of the floating air is high, the contact member 251 moves from the retracted position to the contact position in response to ON (strong) of the floating air. This operation with thick paper corresponds directly to the operation shown in the timing chart of FIG.

  On the other hand, in the thin paper, since the wind pressure of the floating air is low, the contact member 251 remains in the retracted position regardless of whether the floating air is ON (weak). In this case, even if the air blowing portion 212 moves from the lower end position to the upper end position due to wind pressure, the contact member 251 does not contact the side surface of the sheet bundle.

  In this way, in the case of thick paper, the contact member 251 is switched from the retracted position to the contact position when the paper rises, and the card rises by sliding up in the contacted state to create a chance to float the thick paper. be able to. Accordingly, the sheet can be stably separated and floated from the thick sheet bundle without excessively increasing the air volume / wind pressure of the flying air blown to the side surface of the sheet bundle. On the other hand, in the case of paper such as thin paper other than thick paper, the contact member 251 continues to be set at the retracted position, so that the contact member 251 contacts the side surface of the sheet bundle as shown in FIG. Therefore, deformation such as buckling or wrinkle of the sheet caused by the deformation is not caused, and conveyance failure due to deformation can be prevented in advance.

  In addition, although it has been described that the air blowing fan 211 of the modified example can switch the air volume to two levels (strong / weak), the present invention is not limited to the above form, and the air volume of three or more levels corresponding to the amount of paper drooping. It is good also as a structure which can switch the intensity of.

  Further, the predetermined value that is determined to be cardboard can be changed, and can be changed as appropriate by, for example, the user operating the operation panel 130.

(Various variations)
In the present embodiment, the air blowing unit 212 and the blowing port are moved up and down by the wind pressure of the blower fan 211. However, the configuration is not limited thereto, and the air blowing unit 212 is configured by components such as a drive motor, a solenoid, and an actuator. It is good also as a structure moved up and down. At that time, the rising speed and timing of the air blowing section 212 may be controlled according to the operation timing of the blower fan 211 or the contact position of the contact member 251.

  In addition, regarding the contact mechanism 25, the configuration in which the contact state of the contact member 251 at the contact position or the retracted position is switched depending on the presence / absence or increase / decrease of the wind pressure (air volume) of the blower fan 211 is not limited thereto. It is good also as a structure which switches a contact state with components, such as a drive motor, a solenoid, and an actuator. Further, in this configuration, the contact state may be controlled to be switched according to the setting information of the thick paper / thin paper.

  Furthermore, although the example which performs switching of the production | generation / stop of the airflow sent to the air blowing part 212 as shown to Fig.4 (a) and FIG.4 (b) by ON / OFF operation of the ventilation fan 211 was demonstrated, Not limited. A shutter that blocks airflow from the blower fan 211 may be provided on the upstream side of the air blowing portion 212 inside the duct, and the supply of air to the air blowing portion 212 may be controlled by opening and closing the shutter.

  In the present embodiment, the air blowing portion 212 and the abutting member 251 are disposed at positions facing both side surfaces in the width direction of the sheet bundle. However, the present invention is not limited to this, and may be disposed only on one side surface. Alternatively, it may be arranged along with the side surface in the width direction or on the side surface in the front-rear direction instead of this.

  Further, in the present embodiment, the air suction paper feeding unit 24 and the front air blowing unit 23 including the suction fan 241, the paper transport belt 242 and the like are used, but instead, a pickup roller and a pair of double feed prevention rollers are used. An air assist type paper feeder provided may be used.

  In this embodiment, the control unit 110 of the image forming apparatus 100 controls the paper feeding device 200. However, the present invention is not limited thereto, and the paper feeding device 200 is also provided with a control unit. In cooperation with the unit 110, the driving of the blower fan 211 and the air suction paper feeding unit 24 may be controlled.

  In addition, the contact member 251 may not rub the cardboard due to deterioration over time, or the paper may slide without being rubbed by the friction coefficient of the contact member 251 provided in the contact mechanism 25. In preparation for such a case, the contact member 251 may be configured to be detachable from the contact mechanism 25. The user can select the contact member 251 having an appropriate coefficient of friction according to the amount of paper to be used and attach it to the contact mechanism 25. If the cardboard cannot be transported even when the contact member 251 is used, the image forming apparatus causes the contact member 251 to deteriorate over time, or to rub the paper with the friction coefficient of the contact member included in the contact mechanism 25. Therefore, it may be determined that the contact member 251 is changed on the operation panel 130.

  In addition, the present invention is construed as being limited only by the scope of the claims, and is not construed as being limited to the above-described apparatus configuration example, assumed example, or the like of the present embodiment.

10 image forming system,
100 image forming apparatus,
110 control unit,
120 image forming unit,
130 operation panel,
140 image reading unit,
150 paper transport section,
151 registration rollers,
160 fixing unit,
170 Main body paper feed unit,
200 paper feeder,
20 paper feed unit,
21 Side control part,
21s paper regulation,
210 duct housing,
211 Blower fan (blower part),
212 Air blowing part,
212a outlet,
213 Lower duct,
22 Pre-registration rollers,
23 Tip blower,
23a outlet,
231 blower fan,
24 Air suction paper feeding unit (paper feeding unit),
241 suction fan,
242 paper transport belt,
243, 244, 245 rollers,
246 duct,
247 actuator,
247a rotation axis,
25 contact mechanism,
251 contact member,
252 support member,
252a rotation axis,
252b arm,
252c wind receiving plate,
253 Spring,
PS1, PS2, PS3 photoelectric sensor,
27 Tip restriction plate,
28 rear end regulating plate,
29 Loading section.

Claims (9)

A stacking unit for stacking a stack of sheets on which a plurality of sheets are stacked;
An air blowing portion capable of moving up and down, provided with an air blowing port facing the side surface of the stacked sheet stack;
A blower unit that sends air to the air blowing unit to form an air flow from the air blowing port toward a side surface of the sheet bundle;
A paper feeding unit that feeds the uppermost paper that is separated from the paper bundle by the airflow and floats;
An abutting member that moves up and down integrally with the air blowing portion;
With
When the paper is fed, the contact member is brought into contact with a side surface of the sheet bundle facing the air blowing port, and the abutting contact member is raised together with the air blowing unit;
Paper feeder. A switching mechanism for switching the contact member to a contact position that contacts the side surface of the sheet bundle and a retracted position that does not contact;
The contact member is switched from the retracted position to the contact position when the switch is raised by the switching mechanism, and is set to the retracted position except when the lift is performed.
The paper feeding device according to claim 1. The contact member is switched to the contact position by the switching mechanism before the ascent starts.
The sheet feeding device according to claim 2. A switching mechanism for switching the contact member to a contact position that contacts the side surface of the sheet bundle and a retracted position that does not contact;
When the sheet stacked on the stacking unit is thick paper and is raised, the abutment member is switched from the retracted position to the contact position when the paper is raised, and other than the thick paper or when the paper is raised Is set at the retracted position,
The paper feeding device according to claim 1. The switching mechanism switches the contact member to the contact position and the retracted position according to the presence or absence or increase or decrease of the wind pressure of the airflow formed by the air blowing unit.
The sheet feeding device according to any one of claims 2 to 4. The blowing section can be switched between a first wind pressure corresponding to thick paper and a second wind pressure lower than the first wind pressure corresponding to thin paper,
The sheet feeding according to claim 5, wherein the contact member is set at the contact position by the switching mechanism at the first wind pressure, and is set at the retracted position by the second wind pressure. apparatus. The stacking unit is provided with a side surface regulating unit that regulates an end portion in the width direction orthogonal to the sheet conveyance direction,
The friction coefficient with the sheet of the contact surface of the contact member is larger than the friction coefficient with the sheet of the sheet regulation surface of the side regulating part,
The paper feeding device according to any one of claims 1 to 6.   The contact member is disposed in the air flow from the air blowing port toward the side surface of the sheet bundle, and a projected area of the contact member viewed from a direction perpendicular to the air blowing port is The paper feeding device according to any one of claims 1 to 7, wherein the paper feeding device is smaller than an area of the air outlet. A paper feeding device according to any one of claims 1 to 8,
An image forming unit that forms an image on paper fed from the paper feeding device;
An image forming system.