Feeding device and image forming apparatus

Abstract

To provide a feeding device and an image formation device which can well restrict floating of sheets regardless of sheet types.SOLUTION: A feeding device has a sheet stacking part for stacking sheets, air blowing means for blowing air onto sheets stacked on the sheet stacking part to float them, and sheet position restricting members such as side fences 13 for restricting positions of sheets stacked on the sheet stacking part. The feeding device is structured as such that: it is provided with floating position restricting members serving as floating suppression members 13b that protrude from the sheet position restricting members and oppose sheets stacked on the sheet stacking part from above to restrict floating of sheets; and the protruding state in which the floating position restricting members protrude from the sheet position restricting members can be changed.SELECTED DRAWING: Figure 12

Description

[Technical Field]

[0001] The present invention relates to a feeding device and an image forming apparatus. [Background technology]

[0002] Conventionally, a feeding device has been known that includes a sheet stacking section for stacking sheets, an air blowing means for blowing air onto the sheets stacked on the sheet stacking section to lift them up, a sheet position regulating member for regulating the position of the sheets stacked on the sheet stacking section, and a floating position regulating member that protrudes from the sheet position regulating member and faces the sheets stacked on the sheet stacking section from above to regulate the floating position of the sheets.

[0003] Patent document 1 describes a feeding device in which, when the air blowing means is blowing air onto the sheets loaded on the sheet stacking section, the floating position regulating member protrudes from the side fence that serves as the sheet position regulating member, and when air is not being blown onto the sheets, the floating position regulating member is positioned within the sheet position regulating member. Summary of the Invention [Problem to be solved by the invention]

[0004] However, depending on the type of sheet, there are cases where the floating position regulating member is unable to regulate the floating position satisfactorily. [Means for solving the problem]

[0005] In order to solve the above-mentioned problems, the present invention provides a feeding device including a sheet stacking section for stacking sheets, air blowing means for blowing air onto the sheets stacked on the sheet stacking section to float them up, a sheet position regulating member for regulating the position of the sheets stacked on the sheet stacking section, and a floating position regulating member that protrudes from the sheet position regulating member and faces the sheets stacked on the sheet stacking section from above to regulate the floating position of the sheets, the feeding device being configured so that a protruding state of the floating position regulating member protruding from the sheet position regulating member can be changed, and including a protruding state changing means for changing the protruding state, the protruding state changing means comprising: The sheet position restricting member is attached to a drive belt that is stretched between a driven roller and a drive roller, and a drive motor that rotates the drive belt. The drive motor rotates the drive belt to set the drive belt in the protruding state, thereby changing the amount of protrusion from the sheet position restricting member. It is characterized by the following. [Effects of the Invention]

[0006] According to the present invention, floating of the sheet can be effectively restricted regardless of the type of sheet. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic configuration diagram of an image forming apparatus including a sheet feeding device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic explanatory diagram of a sheet feeding device. [Figure 3] FIG. 2 is a perspective view showing a schematic configuration of one storage tray of the sheet feeding device. [Figure 4] FIG. [Figure 5] FIG. [Figure 6] 10A and 10B are diagrams illustrating a state in which the uppermost sheet is attracted to the suction belt when the sheets are cardboard. [Figure 7] 10A and 10B are diagrams illustrating a state in which the topmost sheet is adsorbed to the adsorption belt when the sheets are thin paper. [Figure 8] 10A and 10B are diagrams illustrating the relationship between the protrusion angle of the anti-lifting member relative to the side fence and the pressing force of the anti-lifting member against the sheet. [Figure 9] FIG. 10 is a control block diagram of a control for changing the protruding state of the anti-floating member. [Figure 10]FIG. 2 is a perspective view showing an example of a sheet type determination device. [Figure 11] FIG. 2 is a control block diagram of a sheet type determination device. [Figure 12] FIG. 10 is a diagram showing an example of a protrusion state changing device. [Figure 13] FIG. 10 is a diagram showing another example of the protrusion state changing device. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment of a sheet feeding device to which the present invention is applied will be described below. FIG. 1 is a schematic diagram of an image forming apparatus 1 equipped with a sheet feeding device according to this embodiment. 1, the image forming apparatus 1 includes an image forming apparatus main body 100 as an image forming means for forming an image on a sheet, and a sheet feeding device 200 for feeding a sheet to the image forming apparatus main body 100. The sheet feeding device 200 is provided on a side of the image forming apparatus main body 100.

[0009] There are no particular limitations on the recording method of the image forming apparatus main body 100, and any method such as electrophotography or inkjet can be used. A sheet feeder from the sheet feeding device 200 is provided on the right side of the image forming apparatus main body 100 in Fig. 1. This sheet feeder is provided with an opening for receiving sheets and a conveying means for conveying sheets.

[0010] FIG. 2 is a schematic explanatory diagram of the sheet feeding device 200. As shown in FIG. 2, the sheet feeding device 200 includes two storage trays 10, one above the other. Each storage tray 10 includes a sheet placing table 11 as a sheet stacking section for stacking a sheet stack Pt. Each storage tray 10 can store, for example, a maximum of approximately 2,500 sheets.

[0011] Examples of sheets include paper, coated paper, label paper, overhead projector sheets, films, and prepregs. Prepregs are mainly used as materials for laminates and multilayer printed wiring boards. Prepregs are produced by continuously impregnating a long substrate, such as glass cloth, paper, nonwoven fabric, or aramid cloth, with a resin varnish primarily composed of a thermosetting resin, such as epoxy resin or polyimide resin, and then heating and drying the substrate before cutting it into sheets.

[0012] A feeding unit 20 is disposed above each storage tray 10 to separate and feed the sheets stacked on the storage tray 10. The feeding unit 20 includes a suction belt 21 and a suction device 23, which are conveying means.

[0013] The sheets stacked on the lower storage tray 10 are conveyed to the image forming apparatus main body 100 by the exit roller pair 80 through the lower conveying path 82. The sheets stacked on the upper storage tray 10 are conveyed to the image forming apparatus main body 100 by the exit roller pair 80 through the upper conveying path 81.

[0014] Fig. 3 is a perspective view showing the schematic configuration of one storage tray 10 of the sheet feeding device 200. For ease of understanding, Fig. 3 shows the feeding unit 20 shifted in the direction of arrow A from its original location. The suction belt 21 of the feeding unit 20, which serves as a feeding means, is stretched by two tension rollers 22a and 22b. The suction belt 21 has suction holes that penetrate from the front side to the back side over the entire circumferential area. A suction device 23 is provided inside the suction belt 21.

[0015] The suction device 23 is connected to a suction fan that sucks air through an air duct, which is an air flow path, and generates a negative pressure downward by the suction device 23, thereby causing the sheet to be adsorbed to the lower surface of the suction belt 21. The air sucked by this suction device 23 is called suction air.

[0016] The storage tray 10 also includes a blower 17, which is an air blowing unit that blows air onto the upper sheets of the sheet stack Pt. The blower 17 includes a front blower 12 and a side blower .

[0017] The front blower 12 blows air toward the top end of the sheet stack Pt (the downstream end in the feeding direction). The front blower 12 includes a floating nozzle that guides air in a direction to float the sheet stack Pt, a separation nozzle that guides air between the topmost floating sheet and the second floating sheet to separate them, and a floating blower 15 that sends air to the floating nozzle. The front blower 12 also includes a separation blower 16 that sends air to the separation nozzle.

[0018] Of the nozzles, the air blown from the floating nozzle is called floating air, and the air blown from the separation nozzle is called separation air. The floating air is blown in the direction of arrow a1 in FIG. 4 from a position facing the top leading edge (downstream end in the feeding direction) of the sheet stack Pt, and is blown onto the top leading edge (downstream end in the feeding direction) of the sheet stack Pt. The separation air is blown in the direction of arrow a2 in FIG. 4 from a position facing the top leading edge (downstream end in the feeding direction) of the sheet stack Pt, and is blown onto the gap between the top sheet adsorbed to the suction belt 21 and the second floated sheet. By blowing separation air between the top sheet and the second floated sheet, the separation air flows upstream in the sheet conveying direction, separating the top sheet from the second sheet.

[0019] The side blower 14 is provided on a pair of side fences 13, which serve as sheet position restricting members that restrict the widthwise position of the sheet stack, and blows air toward the upper side of the sheet stack Pt in the direction indicated by the arrow b in the figure. The side blower 14 is provided with a side floating nozzle that guides air in a direction to separate and float the sheet stack Pt, and has a side blower 14a that sends air into this nozzle. The air blown from the side floating nozzle in the direction indicated by the arrow b in the figure is called side air.

[0020] The side air is discharged from outlets 13a provided at positions of each side fence 13 facing the upper part of the sheet stack Pt, and is blown onto the side surface of the upper part of the sheet stack Pt. The air blown from the front blower 12 and the outlets 13a of the pair of side fences 13 causes the upper sheets of the sheet stack to float.

[0021] Furthermore, each side fence 13 is provided with a sheet lift-up suppression member 13b that serves as a lift-up position restricting member. The sheet lift-up suppression member 13b is formed so as to protrude from the top of the side fence 13 toward the center in the width direction. The sheet lift-up suppression member 13b restricts a lifted sheet from being blown away.

[0022] The storage tray 10 also includes an end fence 25 that aligns the rear end of the sheet stack Pt loaded on the sheet loading table 11, which serves as a sheet loading section. The sheet loading table 11 is configured to be able to move up and down in the direction of arrow B in the figure by an elevator device 19, which serves as a loading section moving means.

[0023] Next, the feeding operation will be described. FIG. 4 is a diagram illustrating the feeding operation. The feeding operation mainly consists of four processes: a floating process shown in FIG. 4(a), a suction process shown in FIG. 4(b), a separation process shown in FIG. 4(c), and a feeding process shown in FIG. 4(d). When the feeding operation starts, the floating process shown in Fig. 4(a) begins. In the floating process, the suction belt 21 is stopped and the blower 17 starts blowing air, separation air, and side air onto the sheets. By blowing the floating air and side air onto the leading edge of the top of the sheet stack, the upper sheets of the sheet stack are floated, and at least the uppermost sheet of the floated sheets is floated to a height where the suction force of the suction device 23 acts.

[0024] 4(b) at the timing when at least the uppermost sheet among the floated sheets is floated to a height at which the suction force of the suction device 23 acts. In the suction process, the suction device 23 starts suction (starts driving the suction fan) and generates negative pressure below the belt adsorption surface 21a of the adsorption belt 21. Then, the floated sheets move toward the adsorption belt 21 due to the negative pressure, and the uppermost sheet P1 is adsorbed to the belt adsorption surface 21a of the adsorption belt 21.

[0025] In the explanation of Figure 4, the suction device 23 starts suction when the top sheet rises to a height at which the suction force of the suction device 23 acts, but the suction device 23 may also start suction when the blower device 17 starts blowing air.

[0026] When the top sheet is adsorbed to the adsorption belt 21, the negative pressure below the belt adsorption surface 21a is released, and separation air flows between the top sheet P1 adsorbed to the adsorption belt 21 and the second sheet, thereby separating the top sheet P1 from the second sheet.

[0027] Once the upper sheet is adsorbed to the adsorption belt 21 in this way, the process moves to the separation process shown in Figure 4(c). In the separation process, the shutter is turned ON (moved to the closed position) to stop blowing the floating air. Also, the separation blower 16 is stopped, or the shutter that blocks the separation air is driven to stop blowing the separation air. By stopping the blowing of the floating air in this way, the floating force applied to the sheets by the air is reduced, and the second and subsequent sheets fall. As a result, the distance between the uppermost sheet P1 and the second sheet P2 adsorbed to the adsorption belt 21 increases by more than a predetermined value, and the uppermost sheet is separated from the second sheet.

[0028] When the distance between the belt attraction surface 21a of the attraction belt 21 and the second sheet P2 becomes equal to or greater than a predetermined value, the process proceeds to the feeding process, as shown in Fig. 4(d). In the feeding process, the feeding motor is driven to rotate the attraction belt 21, and the uppermost sheet attracted to the attraction belt 21 is fed.

[0029] FIG. 5 is a schematic plan view of the receiving tray 10. As shown in FIG. The leading end of the sheet stack Pt is positioned by leading end restriction plate 41, and the trailing end is positioned by end fence 25. At this time, the sheets are floated by floating air indicated by the black arrows in the figure from front blower 12. Both widthwise sides of the floated sheets abut against sheet floating suppression members 13b provided to protrude from side fences 13, and the floating is restricted by floating suppression members 13b.

[0030] FIG. 6 is a diagram showing a state in which the uppermost sheet P1 is attracted to the attraction belt 21 when the sheets are cardboard. The topmost sheet P1, which has been floated by the side air or floating air, abuts against the floating suppression members 13b on both sides in the width direction of the sheet, and is prevented from floating and is then adsorbed to the suction belt 21. In this embodiment, as described above, side air is constantly blown in the series of sheet feeding operations shown in Fig. 4, so that even after the topmost sheet is adsorbed to the suction belt, an air pocket remains between the topmost sheet and the second sheet, and both sides in the width direction of the topmost sheet are pressed against the floating suppression members 13b.

[0031] Because cardboard is stiff, it does not deform much in a direction that reduces the pressing force with the lift-up suppression member, so the pressing force of the lift-up suppression member on the top sheet adsorbed to the adsorption belt 21 becomes large.

[0032] Furthermore, in the case of thick paper, the volume of the floating air and side air may be increased because it is heavy and difficult to float up, which results in a larger floating force of the side air acting on the top sheet adsorbed to the suction belt, and an even larger pressing force by the floating suppression member against the top sheet adsorbed to the suction belt.

[0033] In this way, when the sheet is thick paper, the pressure applied by the lift suppression member 13b to the uppermost sheet adsorbed to the suction belt 21 is large. Therefore, when the suction belt 21 is rotated to feed the uppermost sheet adsorbed to the suction belt 21, the feeding load becomes large, and there is a risk of feeding failures such as non-feeding. Furthermore, there is a risk of scratches caused by the lift suppression member 13b being generated on both sides of the sheet in the width direction during this feeding.

[0034] In order to prevent poor feeding or scratches caused by the lift-up suppression member 13b, it is preferable to reduce the amount by which the lift-up suppression member 13b protrudes from the side fence 13. By reducing the amount of protrusion, the pressing force of the lift-up suppression member 13b against the top sheet adsorbed to the adsorption belt 21 becomes weaker than when the amount of protrusion is large. As a result, it is possible to prevent poor feeding or scratches when stiff sheets such as cardboard are set in the storage tray 10.

[0035] FIG. 7 is a diagram showing a state in which the uppermost sheet P1 is attracted to the attraction belt 21 when the sheets are thin paper. In the case of thin paper, due to its low stiffness, when both sides of the sheet in the width direction hit the lift-up suppression member, it easily deforms in a direction that reduces the pressing force, and the pressing force applied by the lift-up suppression member to the uppermost sheet adsorbed to the suction belt 21 by the lift-up suppression member can be made weaker than for thick paper. However, because thin paper and other sheets with low stiffness easily deform, if the lift-up suppression member 13b does not protrude much from the side fence 13 and the pressing force applied to the sheet is weak, the sheet may climb over the lift-up suppression member 13b and float excessively. In addition, the blowing of side air during feeding may cause the sheet to flap, which may hinder proper feeding.

[0036] Therefore, when using a sheet with low stiffness such as thin paper, it is preferable to increase the amount by which the lift suppression member protrudes from the side fence 13, unlike when using a sheet with high stiffness such as cardboard. Increasing the amount by which the lift suppression member protrudes from the side fence 13 prevents the sheet from climbing over the lift suppression member 13b, thereby suppressing excessive lift. Furthermore, by increasing the area that suppresses lift, the sheet can be stably brought into contact with the pressure member by blowing side air, suppressing flapping of the sheet during feeding.

[0037] While the above has been explained regarding the amount of protrusion, the pressing force against the floating sheet varies depending on the protrusion angle of the floating suppression member 13b from the side fence. As shown in Figure 8, when the floating suppression member 13b protrudes upward, the pressing force of the floating suppression member 13b against the floating sheet is weaker, and when the floating suppression member 13b protrudes downward, the pressing force of the floating suppression member 13b against the floating sheet is stronger.

[0038] Therefore, when the sheet is stiff, it is preferable that the anti-floating member protrudes upward, which will apply a weaker pressing force to the floating sheet.On the other hand, when the sheet is weak, it is preferable that the anti-floating member protrudes downward, which will apply a stronger pressing force to the floating sheet.

[0039] Furthermore, even slight scratches are noticeable on sheets that are easily scratched, such as coated paper, stored in storage tray 10. Therefore, when using sheets that are easily scratched, such as coated paper, it is preferable to reduce the amount of protrusion of lift-up suppression member 13b or make it protrude upward, thereby weakening the pressing force of lift-up suppression member 13b against the sheet.

[0040] Furthermore, in the case of a sheet whose surface is easily scratched, if the pressing force of the lift suppressing member 13b against the sheet is strong, scratches are likely to occur due to friction with the lift suppressing member during feeding.

[0041] In this way, the optimal protrusion state of the lift suppression member 13b, such as the protrusion amount and protrusion angle, differs depending on the type of sheet. Therefore, in this embodiment, the protrusion state of the lift suppression member 13b relative to the side fence 13 is changed depending on the type of sheet set in the storage tray 10. The characteristic features of this embodiment will be described below with reference to the drawings.

[0042] FIG. 9 is a control block diagram of the control for changing the protruding state of the anti-floating member. A control unit 66 of the sheet feeding device 200 is connected to a host controller 101 of the image forming apparatus main body 100. A sheet type determination device 300 that detects the thickness and type of a sheet is connected to the host controller 101.

[0043] The control unit 66 of the sheet feeding device receives information on the type of sheet set in the storage tray 10 determined by the sheet type determination device 300 from the host controller 101. Based on the received sheet type information, the control unit 66 determines the basis weight, presence or absence of a surface coating, the surface scratch susceptibility, etc., and changes the protruding state of the lift suppression member 13b.

[0044] The sheet type determination device 300 may be connected to the control unit 66 of the sheet feeding device 200, and the sheet type information may be obtained directly from the sheet type determination device 300 without going through the higher-level controller 101. Alternatively, the sheet type information may be obtained by the user inputting the sheet type information set in the storage tray 10 using an operation display unit provided on the image forming apparatus main body.

[0045] FIG. 10 is a perspective view showing an example of the sheet type determination device 300. As shown in FIG. The sheet type determination device 300 has a sheet receiving stand 320 inside the exterior case 301 that receives the sheet P. The sheet receiving stand 320 is biased vertically upward by a spring, so that the sheet inserted into the opening 302 is pressed against a measurement reference surface inside the exterior case 301 that faces the sheet receiving stand 320.

[0046] The user inserts the sheet to be set in the storage tray 10 into the opening 302 of the sheet type determination device 300 until the sheet abuts against the edge surface 303 of the opening 302. The sheet type determination device 300 detects optical information of the sheet inserted into the opening 302 and determines the type of the sheet.

[0047] The sheet type determination device 300 also includes an encoder for detecting the amount of downward movement of the sheet receiving platform 320. Before a sheet is inserted into the opening 302, the sheet receiving platform 320 is pressed against a measurement reference surface. When a sheet is inserted into the opening 302, the sheet receiving platform 320 descends in accordance with the thickness of the sheet, and presses the sheet against the measurement reference surface. Therefore, the amount of descent of the sheet receiving platform 320 detected based on the output of the encoder sensor detected when the sheet is inserted is the same as the thickness of the sheet, and the control unit detects the thickness of the sheet based on the output from the encoder sensor.

[0048] FIG. 11 is a control block diagram of the sheet type determination device 300. As shown in FIG. The sheet type determination device 300 includes a first sheet information detection sensor 310A and a second sheet information detection sensor 310B.

[0049] The first sheet information detection sensor 310A includes a light source 311, a collimator lens 312, light receivers 313, 314, 315, 318, polarizing filters 316, 317, a dark box 319A, etc. The second sheet information detection sensor 310B includes a light receiver 360, a dark box 319B, etc.

[0050] The reflected light reflected from the sheet P includes light reflected on the surface of the sheet P and light reflected inside the sheet P. Furthermore, the reflected light reflected on the surface of the sheet P includes specularly reflected light and diffusely reflected light. Hereinafter, for convenience, the reflected light specularly reflected on the surface of the sheet P will be referred to as "surface specular reflected light," and the reflected light diffusely reflected on the surface of the sheet P will be referred to as "surface diffuse reflected light." The reflected light reflected inside the sheet P will be referred to as "internal reflected light."

[0051] The surface of sheet P is composed of flat and sloped portions, and the smoothness of the sheet surface can be determined by the ratio of surface specular reflected light to surface diffuse reflected light. Light reflected by the flat portions becomes surface specular reflected light, and light reflected by the sloped portions becomes surface diffuse reflected light. The higher the smoothness, the greater the proportion of flat portions, and therefore the greater the amount of surface specular reflected light. The polarization direction of surface specular reflected light and surface diffuse reflected light is the same as the polarization direction of the light incident on the sheet.

[0052] If the sheet P is ordinary printing paper, the internally reflected light is scattered multiple times in the fibers inside the sheet, and so becomes only diffusely reflected light. The polarization direction of the internally reflected light is rotated relative to the polarization direction of the incident light as it passes through the fibers of the sheet and is scattered multiple times.

[0053] The polarizing filters 316 and 317 transmit light with a polarization direction different from that of the incident light. Reflected light, which is a mixture of surface diffuse reflected light and internally reflected light, enters each polarizing filter 316 and 317. Of this, the surface diffuse reflected light is blocked by the polarizing filters 316 and 317. On the other hand, the internally reflected light is a mixture of light with the same polarization as the incident light and light with a polarization different from that of the incident light, and of the internally reflected light, light with a polarization different from that of the incident light passes through the polarizing filters 316 and 317. Therefore, the photoreceivers 314 and 318 receive the internally reflected light with a polarization component different from that of the incident light.

[0054] The inventors have confirmed that the amount of internally reflected light correlates with the thickness and density of the sheet P. This is because the amount of internally reflected light depends on the path length when passing through the fibers of the sheet P. The angle between the surface of the sheet and the line connecting the center of the polarizing filter 316 and the center of the light receiver 314 is different from the angle between the surface of the sheet and the line connecting the center of the polarizing filter 317 and the center of the light receiver 318. Therefore, the amount of internally reflected light incident on the light receiver 314 and the amount of internally reflected light incident on the light receiver 318 are different from each other.

[0055] On the other hand, since no polarizing filter is placed in front of the light receiver 315, the light receiver 315 receives surface diffuse reflected light and internally reflected light. The surface specular reflected light, surface diffuse reflected light, and internally reflected light are incident on the light receiver 313, which is placed in the specular reflection direction of the incident light.

[0056] In the second sheet information detection sensor 310B, the light receiver 360 receives transmitted light that is transmitted through the sheet P out of the light irradiated onto the sheet P from the light source 311.

[0057] Each photoreceiver outputs an electrical signal (current signal) corresponding to the amount of received light to a processing device 330. The processing device 330 has a light source drive circuit 331, a current-voltage conversion circuit 332, an AD conversion circuit 333, etc., and is fixed to an anechoic box 319A. The light source drive circuit 331 outputs a light source drive signal to the light source 311 in response to an instruction from a control unit 340. The current-voltage conversion circuit 332 converts the current signal from each photoreceiver into a voltage signal. The AD conversion circuit 333 converts the analog signal via the current-voltage conversion circuit 332 into a digital signal and outputs it to the control unit 340.

[0058] The control unit 340 determines the type of sheet based on the signals from each light receiver converted into digital signals. For example, the type of sheet, such as the brand, is identified based on the ratio (S1 / S2) between the signal S1 from light receiver 313 and the signal S2 from light receiver 315, the ratio (S3 / S4) between the signal S3 from light receiver 314 and the signal S4 from light receiver 318, the signal from light receiver 360, and the output of the encoder sensor. Specifically, the ratio (S1 / S2), the ratio (S3 / S4), the signal from light receiver 360, and the output of the encoder sensor are stored in the nonvolatile memory of the control unit 340 for each sheet type. The sheet type is identified based on the ratio (S1 / S2), the ratio (S3 / S4), the signal from light receiver 360, and the output of the encoder sensor obtained from the nonvolatile memory.

[0059] The sheet type determination device 300 acquires information about the state of the surface coating from the ratio (S1 / S2) between the signal S1 from the light receiver 313 and the signal S2 from the light receiver 315. The sheet type determination device 300 also acquires information about the susceptibility of the sheet to damage from the sheet density, which is determined from the ratio (S3 / S4) between the signal S3 from the light receiver 314 and the signal S4 from the light receiver 318. The sheet type determination device 300 also acquires information about the basis weight of the sheet from the signal from the light receiver 360 and the output of the encoder sensor. The acquired information about the state of the surface coating, the information about the susceptibility of the sheet to damage, and the information about the basis weight of the sheet may be transmitted to the upper controller 101 as sheet type information.

[0060] FIG. 12 is a diagram showing an example of the protrusion state changing device 40. As shown in FIG. The protrusion state changing device 40 has a protrusion amount changing mechanism 240 that changes the amount of protrusion of the lift suppression member 13b from the side fence 13, and a protrusion angle changing mechanism 140 that changes the protrusion angle from the side fence 13.

[0061] The protrusion amount change mechanism 240 has a drive belt 241 that is stretched between a driven roller 241a and a drive roller 241b, and a belt drive motor 242 that rotates and drives the drive belt 241. The lift suppression member 13b is attached to the stretched region between the driven roller 241a and the drive roller 241b of the drive belt 241. The drive roller 241b is attached to the motor shaft of the belt drive motor 242.

[0062] The protrusion angle change mechanism 140 has a fan-shaped rotating gear 141, a drive gear 143 that meshes with the rotating gear 141, and a gear drive motor 142. The rotating gear 141 is rotatably attached to the shaft of a driven roller 241a. The belt drive motor 242 is attached to the rotating gear 141.

[0063] When there are no more sheets on the sheet placing table 11, the belt drive motor 242 is driven to rotate the drive belt 241 clockwise in the figure, and the lift suppression member 13b that had been protruding from the side fence 13 is stored inside the side fence 13, as shown in Figure 12(a). As a result, when setting a sheet on the sheet placing table 11, the lift suppression member 13b does not get in the way of setting the sheet, and the sheet can be easily set on the sheet placing table 11.

[0064] 12(a), when the storage tray 10 is pulled out from the apparatus main body, the lift suppression member 13b may be stored in the side fence 13. This prevents the lift suppression member 13b from getting in the way when changing the sheet stack set on the sheet placing table 11, when removing the sheet stack set on the sheet placing table 11, or when setting another sheet stack.

[0065] When the storage tray 10 is attached to the device body with a sheet on the sheet placing table 11, the belt drive motor 242 is driven to rotate the drive belt 241 counterclockwise in the drawing. By rotating the drive belt 241 counterclockwise in the drawing, the lift suppression member 13b protrudes from the opening 13c of the side fence 13.

[0066] The control unit 66 of the sheet feeding device 200 receives sheet type information, such as the brand of sheets to be set in the storage tray determined by the sheet type determination device 300, from the upper controller 101. The control unit 66 of the sheet feeding device 200 sets the drive time of the belt drive motor 242 based on the sheet type information received from the upper controller 101, and drives the belt drive motor 242 for the set drive time. As a result, the protrusion amount of the lift suppression member 13b from the side fence 13 corresponds to the thickness and type of the sheets set in the storage tray 10.

[0067] [Table 1]

[0068] Table 1 above is a table summarizing the protrusion amounts of the anti-lift member 13b. The protrusion amount of the side fence of the lift suppression member 13b is determined based on the characteristics obtained from the sheet type information, such as the basis weight, the state of the surface coating (such as the presence or absence of a surface coating and the type of surface coating), and the susceptibility to surface scratches, as shown in Table 1. For example, the basis weight, the state of the surface coating, and the susceptibility to surface scratches may each be weighted, and the protrusion amount may be determined from the total points of these.

[0069] For example, the brand as sheet type information, and the basis weight information corresponding to the brand, the surface coating condition information, and the surface scratch susceptibility information are stored in a nonvolatile memory provided in the control unit 66 of the sheet feeding device 200. Based on the brand information of the sheet determined by the sheet type determination device 300 received from the upper controller 101, the control unit 66 reads out the basis weight information corresponding to the brand information, the surface coating condition information, and the surface scratch susceptibility information from the nonvolatile memory.

[0070] As shown in Table 1, when the basis weight as the thickness information of the sheet set in the storage tray 10 is high, the protrusion amount of the lift-up suppression member 13b is reduced, and when the basis weight as the sheet thickness information is low, the protrusion amount of the lift-up suppression member 13b is reduced. When the basis weight is high, the paper is thick and the sheet is stiff, so as mentioned above, if the protrusion amount of the lift-up suppression member is large, there is a risk of poor feeding or scraping marks. Therefore, when the basis weight is high, the protrusion amount point is set to a small value, and a point with a small protrusion amount is set.

[0071] On the other hand, when the basis weight is low, the paper is thin and the stiffness of the sheet is weak, so if the amount of protrusion of the lift-up suppression member 13b from the side fence 13 is small, the lift-up suppression member 13b may not be able to prevent the sheet from floating up. Therefore, when the sheet set in the storage tray 10 is a sheet with a low basis weight, the protrusion amount point is set to a larger positive point, and the protrusion amount is set to a larger point.

[0072] Furthermore, when the sheets set in the storage tray 10 are coated paper that is glossy and easily scratches are easily noticeable, or sheets with easily scratched surfaces, the protrusion amount point is set to a negative value, and the protrusion point is set in the direction of decreasing the protrusion amount. As a result, when the sheets set in the storage tray 10 are coated paper or sheets with easily scratched surfaces, the protrusion amount of the lift suppression member 13b is reduced, and the pressing force of the lift suppression member 13b against the sheets during feeding can be reduced. As a result, it is possible to prevent scratches from occurring on coated paper or sheets with easily scratched surfaces.

[0073] On the other hand, if the sheets set in the storage tray 10 are uncoated paper that is less likely to show scratches or sheets whose surfaces are less likely to scratch and leave scuff marks, the protrusion amount points are set to a positive value, and the protrusion points are set in the direction in which the protrusion amount increases. Note that for uncoated paper or sheets whose surfaces are less likely to scratch, the protrusion amount points may be set to zero.

[0074] The control unit 66 of the sheet feeding device sets the drive time of the belt drive motor 242 based on the sum of the protrusion amount point set based on the basis weight of the sheet and the protrusion amount point set based on the surface coating and the surface scratchability. By driving the belt drive motor 242 for the set drive time, the protrusion amount of the lift suppression member 13b relative to the side fence 13 can be set to an optimal protrusion amount for the sheets set in the storage tray 10.

[0075] After the anti-lifting member 13b has been protruded a predetermined amount from the side fence 13, the gear drive motor 142 is driven to adjust the protruding angle of the anti-lifting member 13b relative to the side fence 13, as shown in FIG. 12(c).

[0076] Driving the gear drive motor 142 rotates the rotating gear 141. This rotation of the rotating gear rotates the protrusion amount change mechanism 240 around the axis of the driven roller 241a. As a result, the lift-up suppression member 13b, to which the drive belt 241 is attached, tilts, and the protrusion angle of the lift-up suppression member 13b relative to the side fence 13 is changed.

[0077] The control unit 66 of the sheet feeding device sets the rotation direction and drive time of the gear drive motor 142 based on the sheet type information received from the upper controller 101. Then, the belt drive motor 242 is driven in the set rotation direction for the set drive time.

[0078] [Table 2]

[0079] Table 2 above is a table summarizing the protrusion angles of the anti-floating member 13b. The protrusion angle of the lift suppression member 13b relative to the side fence is also determined based on the basis weight, surface coating condition, and surface scratch susceptibility as determined from the sheet type information, as shown in Table 2. As with the protrusion amount, the protrusion angle may also be determined by weighting each of the basis weight, surface coating condition, and surface scratch susceptibility, and then adding up the weights to determine the protrusion angle.

[0080] For example, the rotation direction of the belt drive motor 242 in which the tip of the lift-up suppression member 13b is positioned above the horizontal direction is defined as positive, and the rotation direction of the belt drive motor 242 in which the tip is positioned below the horizontal direction is defined as negative. When the total points are negative, the belt drive motor 242 is rotated counterclockwise in the drawing, causing the lift-up suppression member 13b to protrude downward. On the other hand, when the total points are positive, the belt drive motor 242 is rotated clockwise in the drawing, causing the lift-up suppression member 13b to protrude upward.

[0081] As shown in Table 2, when the basis weight of the sheet set in the storage tray 10 as the thickness information is high, the angle point is set to positive for the floating suppression member 13b, and the point is set so that the floating suppression member 13b protrudes upward from the side fence 13. When the basis weight is high, the paper is thick and stiff, so the pressing force of the floating suppression member 13b against the sheet becomes strong. Therefore, the angle point is set to positive, and the floating suppression member 13b is set to protrude upward from the side fence 13, suppressing the increase in the pressing force of the floating suppression member 13b against the sheet. This prevents poor feeding and the occurrence of scrapes.

[0082] On the other hand, when the basis weight is low, the paper is thin and the sheet is not stiff, so if the pressing force of the lift-up suppression member against the sheet is weak, there is a risk that the lift-up suppression member 13b will not be able to prevent the sheet from floating up. When the sheet set in the storage tray 10 is a sheet with a low basis weight, the angle point is set to a negative value, and the lift-up suppression member 13b is set to protrude downward.

[0083] Furthermore, when the sheets set in the storage tray 10 are glossy coated paper that is easily scratched or sheets whose surfaces are easily scratched, the angle point is set to a positive value so that the lift suppression member 13b protrudes upward. This reduces the pressing force of the lift suppression member 13b against the sheets, making it possible to prevent scratches from occurring on coated paper or sheets whose surfaces are easily scratched.

[0084] On the other hand, when the sheets set in the storage tray 10 are uncoated paper that is less likely to show scratches or sheets whose surfaces are less likely to scratch and are less likely to show scratches, the angle point is set to a negative value. This results in a point setting that causes the lift suppression member 13b to protrude downward. Note that when the sheets are uncoated paper or sheets whose surfaces are less likely to scratch, the angle point may be set to zero.

[0085] The control unit 66 of the sheet feeding device sets the drive time of the gear drive motor 142 based on the absolute value of the sum of the angle point set based on the sheet basis weight and the angle point set based on the surface coating condition and surface scratch susceptibility. If the sum is positive, the gear drive motor 142 is driven clockwise in the figure for the set drive time. This causes the floating suppression member 13b to assume a position in which it protrudes upward from the side fence at a specified protrusion angle. On the other hand, if the sum is negative, the gear drive motor 142 is driven counterclockwise in the figure for the set drive time. This causes the floating suppression member 13b to assume a position in which it protrudes downward from the side fence 13 at a specified protrusion angle. This allows the floating suppression member 13b to be set at the optimal protrusion angle for the sheets set in the storage tray 10.

[0086] The protrusion amount may be set based on the basis weight, and the protrusion angle may be set based on the sheet type and the surface's susceptibility to scratches, or vice versa (the protrusion amount may be set based on the sheet type and the surface's susceptibility to scratches, and the protrusion angle may be set based on the protrusion amount).

[0087] Furthermore, for example, in the case of a sheet with low stiffness, such as thin coated paper, where scratches on the surface are easily noticeable, or a sheet with low stiffness where scratches are easily caused on the surface, the protrusion state of the lift-up suppression member 13b may be changed as follows. That is, the protrusion amount of the lift-up suppression member 13b is increased and the lift-up suppression member 13b is protruded downward at least until the suction process shown in FIG. 4(b) is completed. Then, at the start of the feeding process shown in FIG. 4(d), the lift-up suppression member 13b is changed to protrude upward. This allows the lift-up suppression member 13b to effectively suppress the lift-up of the sheet until the sheet is adsorbed to the suction belt 21. Meanwhile, during feeding, the pressing force of the lift-up suppression member 13b against the sheet being fed by the suction belt 21 can be reduced, thereby suppressing the occurrence of scratches.

[0088] FIG. 13 is a diagram showing another example of the protrusion state changing device 40. As shown in FIG. 13, a protrusion state changing device 40 includes a protrusion angle changing mechanism 140 having a drive belt 145 wound around a driven roller 145a and a drive roller 145b, and a belt drive motor 144 that rotates and drives the drive belt 145. A lift suppression member 13b is attached to a winding region of the drive belt 145 where the drive belt 145 is wound around the driven roller 145a.

[0089] The protrusion amount change mechanism 240 has a holding member 243 that holds the protrusion angle change mechanism 140. This holding member 243 is attached to the side fence 13 so as to be slidable horizontally within a predetermined range. The protrusion amount change mechanism 240 has a pinion gear 244 that meshes with a rack gear that extends horizontally and is provided on the underside of this holding member 243. This pinion gear 244 meshes with a drive gear 245 that is attached to the motor shaft of a gear drive motor 246.

[0090] When there are no more sheets on the sheet placing table 11 or when the storage tray 10 is pulled out from the device body, the belt drive motor 144 is driven to rotate the drive belt 145 clockwise in the figure. As a result, the lift suppression member 13b that had been protruding from the side fence 13 rotates counterclockwise in the figure and is stored inside the side fence 13 as shown in Figure 13(a). As a result, when setting a sheet on the sheet placing table 11, the lift suppression member 13b does not get in the way of setting the sheet, and the sheet can be easily set on the sheet placing table 11.

[0091] When the storage tray 10 is attached to the device body with a sheet on the sheet placing table 11, the belt drive motor 144 is driven to rotate the drive belt 145 counterclockwise in the drawing. By rotating the drive belt 145 clockwise in the drawing, the lift suppression member 13b protrudes from the opening 13c of the side fence 13.

[0092] Then, as shown in FIG. 13(b), the belt drive motor 144 is driven so as to achieve the protrusion angle set based on the sheet type information received by the control unit 66 from the upper controller 101.

[0093] 13(c), by rotating the gear drive motor 246 clockwise in the figure, the holding member 243 moves to the left in the figure. As a result, the protrusion angle change mechanism 140 held by the holding member 243 moves to the left in the figure, and the lift-up suppression member 13b attached to the drive belt 145 of the protrusion angle change mechanism 140 moves to the left in the figure. As a result, the amount of protrusion of the lift-up suppression member 13b relative to the side fence 13 increases. On the other hand, by rotating the gear drive motor 246 counterclockwise in the figure, the lift-up suppression member 13b moves toward the side fence 13, and the amount of protrusion decreases.

[0094] The control unit 66 of the sheet feeding device 200 sets the rotation direction and drive time of the gear drive motor 246 so that the protrusion amount is set based on the sheet type information. Then, by rotating the gear drive motor 246 in the set rotation direction for the set drive time, the protrusion amount of the lift suppression member 13b relative to the side fence 13 can be set to an optimal protrusion amount corresponding to the sheets set in the storage tray 10.

[0095] In the above description, the protrusion state of the lift-up suppression member 13b from the side fence 13 is changed based on three characteristics of the sheet type: basis weight, surface coating condition, and surface scratch susceptibility. However, this is not limiting. For example, the protrusion state of the lift-up suppression member 13b from the side fence 13 may be changed based on the brand of sheets set in the storage tray 10. Specifically, the optimal protrusion state of the lift-up suppression member 13b for each brand of sheet is determined in advance through experiments or the like and stored in the nonvolatile memory of the control unit 66. Then, the control unit 66 acquires brand information as sheet type information from the sheet type determination device 300 received from the upper controller 101, and reads the protrusion state corresponding to the acquired brand information from the nonvolatile memory. The protrusion state change device 40 is then controlled to achieve the read protrusion state, thereby adjusting the protrusion state of the lift-up suppression member 13b from the side fence 13 to the optimal protrusion state corresponding to the brand of sheet.

[0096] In the above description, both the protrusion amount and the protrusion angle of the lift-up suppression member 13b relative to the side fence 13 are changed based on the type of sheet set in the storage tray 10, but it is also possible to change only either the protrusion amount or the protrusion angle. When only the protrusion amount of the lift-up suppression member 13b relative to the side fence 13 is changed based on the sheet set in the storage tray 10, only the protrusion amount changing mechanism shown in Fig. 12 is provided. By providing the protrusion amount changing mechanism shown in Fig. 12, the lift-up suppression member can be stored in the side fence when there is no sheet, and the protrusion amount can be changed to match the sheet.

[0097] On the other hand, when only the protrusion angle of the anti-lift member 13b relative to the side fence 13 is changed based on the type of sheet set in the storage tray 10, only the protrusion angle change mechanism shown in Fig. 13 is provided. By providing the protrusion angle change mechanism shown in Fig. 13, when there is no sheet, the anti-lift member 13b can be stored in the side fence 13 and the protrusion angle can be changed to a value corresponding to the sheet.

[0098] Furthermore, the floating suppression member 13b is configured to be detachable from the side fence 13. A configuration may be provided in which multiple floating suppression members are detachable from the side fence 13 and have different protrusion amounts and protrusion angles from the side fence 13. When a user sets a stack of sheets in the storage tray 10, the user removes the floating suppression member 13b from the side fence 13. After placing the stack of sheets on the sheet loading table 11, the user attaches a floating suppression member corresponding to the sheets of the placed stack of sheets to the side fence. This configuration also makes it possible to change the protruding state of the floating suppression member relative to the side fence 13 to a protruding state corresponding to the sheets to be set.

[0099] The above description is merely an example, and each of the following aspects provides unique effects. (Aspect 1) In a sheet feeding device such as a sheet feeding device 200 including a sheet stacking section such as a sheet placing table 11 for stacking sheets, an air blowing means such as an air blower 17 for blowing air to the sheets stacked on the sheet stacking section to make them float up, a sheet position regulating member such as a side fence 13 for regulating the position of the sheets stacked on the sheet stacking section, and a floating position regulating member such as a floating suppressing member 13b that protrudes from the sheet position regulating member and faces the sheets stacked on the sheet stacking section from above to regulate the floating of the sheets, the protruding state of the floating position regulating member from the sheet position regulating member is configured to be changeable. When the sheets stacked in the sheet stacking section are weak sheets, such as thin paper, the floating position restricting member may not protrude much from the sheet position restricting member or may protrude upward, causing the floating position restricting member to press weakly against the floated sheets, resulting in the following problem: When the sheets float and hit the floating position restricting member, they may deform and overcome the floating position restricting member, causing them to float excessively. Therefore, when the sheets stacked in the sheet stacking section are weak sheets, it is necessary to set the floating position restricting member to protrude a large amount from the sheet position restricting member or to protrude downward, thereby strengthening the pressure of the floating position restricting member against the floated sheets. On the other hand, if the sheets loaded in the sheet stacking section are stiff sheets such as cardboard, if the floating position restricting member presses the floated sheets hard against the floating position restricting member, the sheets may hit the floating position restricting member hard, increasing the load during feeding and causing feeding failures, or the floating position restricting member may leave scratches on the sheets. Therefore, when the sheets loaded in the sheet stacking section are stiff sheets, unlike weak sheets, it is necessary to weaken the pressure of the floating position restricting member on the floated sheets by setting the floating position restricting member to a protruding state in which the amount of protrusion of the floating position restricting member relative to the sheet position restricting member is small or to a protruding state in which the floating position restricting member protrudes upward. In the above-mentioned Patent Document 1, the floating position restricting member only assumes a specified protruding state when protruding from the sheet position restricting member. Therefore, depending on the type of sheets stacked in the sheet stacking section, the floating position restricting member may not be able to properly restrict the sheets. On the other hand, in the first aspect, the protruding state of the floating position restricting member from the sheet position restricting member can be changed. As a result, for example, when a sheet with low stiffness is loaded on the sheet stacking section, as described above, the floating position restricting member can be set to a protruding state in which the floating position restricting member protrudes a large amount from the sheet position restricting member or a protruding state in which the floating position restricting member protrudes downward, thereby making it possible to strengthen the pressure of the floating position restricting member on the floated sheet. On the other hand, for example, when a sheet with high stiffness is loaded on the sheet stacking section, as described above, the floating position restricting member can be set to a protruding state in which the floating position restricting member protrudes a small amount from the sheet position restricting member or a protruding state in which the floating position restricting member protrudes upward, thereby making it possible to weaken the pressure of the floating position restricting member on the floated sheet. In this way, in the first aspect, the floating position regulating member can be set to an optimal protruding state depending on the sheets loaded in the sheet stacking section, and the floating of the sheets can be effectively regulated regardless of the type of sheet.

[0100] (Aspect 2) In the first aspect, the protruding state is such that the amount of protrusion from the seat position restricting member such as the side fence 13 can be changed. As described in the embodiment, this makes it possible to reduce the amount of protrusion from the sheet position regulating member such as the side fence 13 when stiff sheets such as cardboard are loaded on a sheet loading section such as the sheet loading table 11. This makes it possible to suppress an increase in the pressing force of the floating position regulating member such as the floating suppression member 13b against the sheet, thereby suppressing the occurrence of poor feeding and scraping marks. Furthermore, when sheets with low stiffness such as thin paper, or sheets that are easily scratched such as coated paper, or sheets with easily scratched surfaces are loaded in the sheet stacking section, the amount of protrusion from the sheet position regulating member can be increased, which allows the floating position regulating member to effectively regulate floating and prevents excessive floating.

[0101] (Aspect 3) In the first or second aspect, the protruding state is a changeable protruding angle from the seat position restricting member such as the side fence 13. According to this, as explained in the embodiment, when stiff sheets such as cardboard are loaded on a sheet stacking section such as the sheet loading table 11, the floating position regulating member such as the floating suppression member 13b can be set to a protruding angle such that it protrudes upward from the sheet position regulating member such as the side fence 13. This makes it possible to suppress an increase in the pressing force of the floating position regulating member against the sheet, and to suppress the occurrence of poor feeding and scraping marks. Furthermore, when sheets with low stiffness such as thin paper, or sheets that are easily scratched such as coated paper, or sheets with easily scratched surfaces are loaded in the sheet stacking section, the floating position restricting member can be set to a protruding angle such that it protrudes downward from the sheet position restricting member, thereby enabling the floating position restricting member to effectively restrict floating and preventing excessive floating.

[0102] (Aspect 4) In any of aspects 1 to 3, a protrusion state changing means such as a protrusion state changing device 40 that changes the protrusion state is provided, and the protrusion state changing means changes the protrusion state based on at least one of the type and thickness of the sheets loaded on a sheet stacking section such as a sheet loading table 11. As described in the embodiment, this allows the protrusion state of the floating position regulating member such as the floating suppression member 13b relative to the sheet position regulating member such as the side fence 13 to be optimally set according to the sheets loaded on the sheet loading section such as the sheet loading table 11. This effectively prevents poor feeding, excessive floating, and the occurrence of scraping marks.

[0103] (Aspect 5) In an image forming apparatus that forms an image on a sheet fed by a feeding device such as the sheet feeding device 200, the feeding device of any one of the aspects 1 to 4 was used. [Explanation of symbols]

[0104] 1: Image forming device 10: Storage tray 11: Sheet placement table 12: Front air blower 13: Side fence 13a:Discharge port 13b: Floating suppression member 13c: opening 14: Side ventilation device 14a: Side blower 15: Floating Blower 16: Separation blower 17: Air blower 19: Lifting device 20: Feeding unit 21: Suction belt 21a: Belt adsorption surface 25: End fence 40: Protrusion state change device 66: Control section 100: Image forming apparatus main body 101: Upper controller 140: Protrusion angle change mechanism 141: Rotating gear 142: Gear drive motor 143: Drive gear 144: Belt drive motor 145: Drive belt 200: Sheet feeding device 240: Protrusion amount change mechanism 241: Drive belt 242: Belt drive motor 243: Retaining member 244: Pinion gear 245: Drive gear 246: Gear drive motor 300: Sheet type determination device P: Seat P1: Top sheet Pt: Sheet stack [Prior art documents] [Patent documents]

[0105] [Patent Document 1] Patent No. 4544033

Claims

1. a sheet stacking section for stacking sheets; an air blowing means for blowing air onto the sheets stacked on the sheet stacking section to lift them up; a sheet position regulating member that regulates the position of the sheets stacked in the sheet stacking section; a floating position regulating member that protrudes from the sheet position regulating member and faces the sheets stacked on the sheet stacking section from above to regulate a floating position of the sheets, a protruding state of the floating position restricting member from the seat position restricting member can be changed; a protrusion state changing means for changing the protrusion state, The protrusion state change means includes a drive belt stretched over a driven roller and a drive roller, to which the floating position regulating member is attached, and a drive motor that rotates the drive belt, and the drive motor rotates the drive belt to set the protrusion state, thereby changing the amount of protrusion from the sheet position regulating member.

2. 2. The feeding device according to claim 1, The sheet feeding device is characterized in that the protruding state is a changeable angle of protrusion from the sheet position restricting member.

3. 3. The feeding device according to claim 1, The feeding device according to claim 1, wherein the protrusion state changing means changes the protrusion state based on at least one of the type and thickness of the sheets stacked on the sheet stacking section.

4. An image forming apparatus for forming an image on a sheet fed by a feeding device, 4. An image forming apparatus, comprising: a feeding device according to claim 1;

Images