JP7723904B2 - Feeding device and image forming apparatus - Google Patents

Description

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

Conventionally, a feeding device has been known that includes a sheet stacking section for stacking sheets, an air blowing device that blows air at 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 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.

Patent Document 1 describes a feeding device in which, when the air blowing means is blowing air onto sheets stacked on a 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.

However, depending on the type of sheet, the floating position regulating member may not be able to regulate the floating position properly.

In order to solve the above-mentioned problems, the present invention provides a feeding device comprising a sheet stacking section for stacking sheets, an air blowing means for blowing air at 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, wherein the protruding state of the floating position regulating member protruding from the sheet position regulating member is changeable, and the device comprises a protrusion state changing means for changing the protrusion state, the protrusion state changing means having a drive belt that is stretched between a driven roller and a drive roller and has the floating position regulating member attached to it, and a drive motor for rotating the drive belt, and the drive motor rotates the drive belt to set the drive belt to the protruding state, thereby changing the amount of protrusion from the sheet position regulating member .

This invention effectively prevents sheet lift regardless of the type of sheet.

1 is a schematic configuration diagram of an image forming apparatus including a sheet feeding device according to an embodiment of the present invention. FIG. 2 is a schematic explanatory diagram of a sheet feeding device. FIG. 2 is a perspective view showing a schematic configuration of one storage tray of the sheet feeding device. FIG. FIG. 10A and 10B are diagrams illustrating a state in which the uppermost sheet is attracted to the suction belt when the sheets are cardboard. 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. 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. FIG. 4 is a control block diagram of a control for changing the protruding state of the anti-floating member. FIG. 2 is a perspective view showing an example of a sheet type determination device. FIG. 2 is a control block diagram of a sheet type determination device. FIG. 10 is a diagram showing an example of a protrusion state changing device. FIG. 10 is a diagram showing another example of the protrusion state changing device.

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.

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

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, approximately 2,500 sheets.

Examples of sheets include paper, coated paper, label paper, overhead projector sheets, film, and prepreg. Prepreg is primarily used as a material for laminates and multilayer printed wiring boards. Prepreg is made by continuously impregnating a long substrate such as glass cloth, paper, nonwoven fabric, or aramid cloth with a resin varnish primarily made of a thermosetting resin such as epoxy resin or polyimide resin, then heating and drying it before cutting it into sheets.

Above each storage tray 10, a feeding unit 20 is located to separate and feed the sheets stacked on the storage tray 10. This feeding unit 20 is equipped with a suction belt 21 and a suction device 23, which serve as conveying means.

Sheets loaded on the lower storage tray 10 are transported through the lower transport path 82 and by the exit roller pair 80 to the image forming device main body 100. Sheets loaded on the upper storage tray 10 are transported through the upper transport path 81 and by the exit roller pair 80 to the image forming device main body 100.

Figure 3 is a perspective view showing the general configuration of one storage tray 10 of the sheet feeding device 200. For ease of understanding, Figure 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 the 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, all around the periphery. A suction device 23 is provided inside the suction belt 21.

The suction device 23 is connected to a suction fan that sucks air through an air duct, which is an air flow path. The suction device 23 generates negative pressure downward, which acts to adsorb the sheet to the underside of the suction belt 21. The air sucked into this suction device 23 is called suction air.

The storage tray 10 also includes an air blower 17, which is an air blowing device that blows air onto the upper sheets of the sheet stack Pt. This air blower 17 includes a front air blower 12 and a side air blower 14.

The front blower 12 blows air toward the top tip of the sheet stack Pt (the downstream end in the feeding direction). This front blower 12 is equipped with 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. This front blower 12 also has a separation blower 16 that sends air to the separation nozzle.

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 Figure 4 from a location facing the upper leading edge (downstream end in the feeding direction) of the sheet stack Pt, and is blown onto the upper 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 Figure 4 from a location facing the upper leading edge (downstream end in the feeding direction) of the sheet stack Pt, and is blown between the topmost sheet adsorbed to the suction belt 21 and the second floated sheet. By blowing separation air between the topmost sheet and the second floated sheet, the separation air flows upstream in the sheet conveyance direction, separating the topmost sheet from the second sheet.

The side blower 14 is mounted on a pair of side fences 13, which act as sheet position control members that regulate the widthwise position of the sheet stack, and blows air toward the upper side of the sheet stack Pt in the direction indicated by arrow b in the figure. This side blower 14 is equipped with a side floating nozzle that guides air in the direction of separating and floating the sheet stack Pt, and has a side blower 14a that sends air into this nozzle. The air blown from this side floating nozzle in the direction indicated by arrow b in the figure is called side air.

Side air is discharged from outlets 13a located on each side fence 13 at a position facing the top of the sheet stack Pt, and is blown onto the side of the top of the sheet stack Pt. The air blown from the front blower 12 and the outlets 13a of the pair of side fences 13 lifts the upper sheets of the sheet stack.

In addition, each side fence 13 is provided with a sheet lift suppression member 13b that acts as a lift position regulating member. The sheet lift suppression member 13b is formed to protrude from the top of the side fence 13 toward the center in the width direction. The sheet lift suppression member 13b regulates the lifted sheet so that it does not get blown away.

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 platform 11, which serves as the sheet loading section. The sheet loading platform 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 the loading section movement means.

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).
4A begins. In the floating process, the air blower 17 starts blowing air while the suction belt 21 is stopped, and floating air, separation air, and side air are blown onto the sheets. The floating air and side air are blown onto the leading edge of the upper part of the sheet stack, thereby floating multiple sheets at the top of the sheet stack, and at least the uppermost sheet of the floated sheets is raised to a height where the suction force of the suction device 23 acts.

When at least the topmost sheet among the floated sheets has risen to a height where the suction force of the suction device 23 can be applied, the suction process shown in Figure 4(b) begins. In the suction process, the suction device 23 starts suction (the suction fan starts to operate), generating negative pressure below the belt suction surface 21a of the suction belt 21. The negative pressure then moves the floated sheets toward the suction belt 21, and the topmost sheet P1 is adsorbed to the belt suction surface 21a of the suction belt 21.

In the explanation of Figure 4, the suction device 23 starts suction when the top sheet is lifted to a height where the suction force of the suction device 23 acts, but the suction device 23 may start suction when the air blower 17 starts blowing air.

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

Once the upper sheet has been adsorbed to the suction 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 the blowing of floating air. The separation blower 16 is also stopped, or the shutter that blocks the separation air is driven to stop the blowing of separation air. By stopping the blowing of floating air in this way, the floating force exerted on the sheets by the air is reduced, causing the second and subsequent sheets to fall. As a result, the distance between the uppermost sheet P1 and the second sheet P2 adsorbed to the suction belt 21 becomes equal to or greater than a predetermined value, and the uppermost sheet is separated from the second sheet.

When the distance between the belt suction surface 21a of the suction belt 21 and the second sheet P2 is equal to or greater than a predetermined value, the process moves to the feeding process, as shown in Figure 4(d). In the feeding process, the feeding motor is driven to rotate the suction belt 21, and the topmost sheet adsorbed to the suction belt 21 is fed.

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

FIG. 6 is a diagram showing a state in which the topmost 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 Figure 4, so that even after the topmost sheet is adsorbed to the suction belt, air remains trapped between the topmost sheet and the next sheet, and both sides in the width direction of the topmost sheet are pressed against the floating suppression members 13b.

Because cardboard is stiff, it does not deform much in a direction that reduces the pressing force against the lift-up suppression member, so the pressing force applied by the lift-up suppression member to the top sheet adsorbed to the suction belt 21 becomes large.

In addition, in the case of thick paper, its weight makes it difficult to float, so the volume of floating air and side air may be increased. As a result, the floating force of the side air acting on the top sheet adsorbed to the suction belt increases, and the pressing force of the floating suppression member on the top sheet adsorbed to the suction belt becomes even greater.

As such, when using thick paper, the pressure applied by the lift suppression member 13b to the top sheet adsorbed to the suction belt 21 is large. Therefore, when the suction belt 21 is rotated to feed the top sheet adsorbed to the suction belt 21, the feeding load becomes large, which may result in feeding problems such as non-feeding. Furthermore, during this feeding, there is a risk of scratches caused by the lift suppression member 13b on both sides of the sheet's width.

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

FIG. 7 is a diagram showing a state in which the topmost 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 top sheet adsorbed to the suction belt 21 by the lift-up suppression member can be made weaker than for thick paper. However, because sheets with low stiffness such as thin paper deform easily, 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.

For this reason, when using a weak sheet 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 stiff sheet 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 suppression member by blowing side air, suppressing flapping of the sheet during feeding.

The above explains the amount of protrusion, but the pressing force against the floating sheet also 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.

Therefore, when using a stiff sheet, it is preferable for the anti-floating member to protrude upward, which will apply a weaker pressing force to the floating sheet. On the other hand, when using a weak sheet, it is preferable for the anti-floating member to protrude downward, which will apply a stronger pressing force to the floating sheet.

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

In addition, if the sheet has a surface that is easily scratched, if the pressing force of the anti-floating member 13b against the sheet is strong, scratches are likely to occur due to friction with the anti-floating member during feeding.

As such, the optimal protrusion state, such as the protrusion amount and protrusion angle of the anti-floating member 13b, varies depending on the type of sheet. Therefore, in this embodiment, the protrusion state of the anti-floating member 13b relative to the side fence 13 is changed depending on the type of sheet set in the storage tray 10. Below, the characteristics of this embodiment will be explained using the drawings.

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

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, surface scratch susceptibility, etc., and changes the protrusion state of the lift suppression member 13b.

The sheet type determination device 300 may be connected to the control unit 66 of the sheet feeding device 200, and sheet type information may be obtained directly from the sheet type determination device 300 without going through the host controller 101. Alternatively, sheet type information may be obtained by having the user input information about the type of sheets placed in the storage tray 10 using an operation display unit provided on the image forming device main body.

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 for receiving a sheet P inside an exterior case 301. 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.

The user inserts the sheet to be placed 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 the optical information of the sheet inserted into the opening 302 and determines the type of the sheet.

The sheet type determination device 300 also has 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 the 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, pressing 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 when the sheet is inserted is the same as the sheet thickness, and the control unit detects the sheet thickness based on the output from the encoder sensor.

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

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

The reflected light reflected from sheet P includes light reflected from the surface of sheet P and light reflected inside sheet P. Furthermore, the reflected light reflected from the surface of sheet P includes specularly reflected light and diffusely reflected light. For convenience, the reflected light specularly reflected from the surface of sheet P will be referred to as "surface specularly reflected light," and the reflected light diffusely reflected from the surface of sheet P will be referred to as "surface diffusely reflected light." The reflected light reflected inside sheet P will be referred to as "internal reflected light."

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 from flat portions becomes surface specular reflected light, and light reflected from sloped portions becomes surface diffuse reflected light. The greater 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 light incident on the sheet.

If sheet P is ordinary printing paper, the internally reflected light is scattered multiple times within the fibers inside it, resulting in 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.

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

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

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 light receiver 313, which is placed in the specular reflection direction of the incident light, receives surface specular reflected light, surface diffuse reflected light, and internally reflected light.

The second sheet information detection sensor 310B has a light receiver 360 that receives the transmitted light that passes through the sheet P from the light source 311.

Each photoreceiver outputs an electrical signal (current signal) corresponding to the amount of light received to the processing device 330. The processing device 330 includes a light source drive circuit 331, a current-voltage conversion circuit 332, an AD conversion circuit 333, and is fixed to the dark box 319A. The light source drive circuit 331 outputs a light source drive signal to the light source 311 in response to instructions from the 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 received via the current-voltage conversion circuit 332 into a digital signal and outputs it to the control unit 340.

The control unit 340 determines the sheet type based on the signals from each light receiver converted into digital signals. For example, the sheet type, such as 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 non-volatile memory of the control unit 340 stores the ratio (S1/S2), ratio (S3/S4), signal from light receiver 360, and encoder sensor output for each sheet type. The sheet type is identified from the ratio (S1/S2), ratio (S3/S4) obtained from the non-volatile memory, the signal from light receiver 360, and the output of the encoder sensor.

The sheet type determination device 300 obtains information regarding the condition 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. It also obtains information regarding the sheet's susceptibility 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. It also obtains information regarding the sheet's basis weight from the signal from the light receiver 360 and the output of the encoder sensor. The obtained information regarding the surface coating condition, the sheet's susceptibility to damage, and the sheet's basis weight may be transmitted to the upper controller 101 as sheet type information.

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 13 b from the side fence 13 , and a protrusion angle changing mechanism 140 that changes the protrusion angle from the side fence 13 .

The protrusion amount change mechanism 240 includes a drive belt 241 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 tensioned area 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.

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 the driven roller 241a. The belt drive motor 242 is attached to the rotating gear 141.

When there are no more sheets on the sheet loading platform 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 protrudes from the side fence 13 is stored inside the side fence 13, as shown in Figure 12(a). This prevents the lift suppression member 13b from interfering with sheet loading on the sheet loading platform 11, making it easy to load sheets onto the sheet loading platform 11.

Also, when the storage tray 10 is pulled out from the device body, the lift suppression member 13b may be stored within the side fence 13, as shown in Figure 12(a). This prevents the lift suppression member 13b from getting in the way when changing the sheet stack set on the sheet loading table 11, removing the sheet stack set on the sheet loading table 11, or setting a different sheet stack.

When the storage tray 10 is attached to the device body with a sheet on the sheet loading platform 11, the belt drive motor 242 is driven to rotate the drive belt 241 counterclockwise in the figure. By rotating the drive belt 241 counterclockwise in the figure, the lift suppression member 13b protrudes from the opening 13c in the side fence 13.

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 amount of protrusion of the lift suppression member 13b from the side fence 13 corresponds to the thickness and type of sheets set in the storage tray 10.

Table 1 above is a table summarizing the protrusion amounts of the anti-floating 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.

For example, the non-volatile memory provided in the control unit 66 of the sheet feeding device 200 stores the brand as sheet type information, as well as the basis weight information corresponding to that brand, information on the surface coating condition, and information on the surface's susceptibility to scratches. Based on the sheet brand information determined by the sheet type determination device 300 received from the higher-level controller 101, the control unit 66 reads the basis weight information corresponding to the brand information, information on the surface coating condition, and information on the surface's susceptibility to scratches from the non-volatile memory.

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 small, and a point with a small protrusion amount is set.

On the other hand, when the basis weight is low, the paper is thin and the sheet is not stiff, so if the amount by which the anti-floating member 13b protrudes from the side fence 13 is small, the anti-floating 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 points are set to a larger positive point, and the protrusion amount is set to a larger point.

Furthermore, when the sheet set in the storage tray 10 is coated paper that is glossy and easily scratched, or a sheet with a scratch-prone surface, 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 sheet set in the storage tray 10 is coated paper or a sheet with a scratch-prone surface, the protrusion amount of the lift suppression member 13b is reduced, and the pressing force of the lift suppression member 13b against the sheet during feeding can be reduced. As a result, it is possible to prevent scratches from occurring on coated paper or sheets with a scratch-prone surface.

On the other hand, if the sheet set in the storage tray 10 is uncoated paper, which is less likely to show scratches, or a sheet with a surface that is less likely to scratch and leave scuff marks, the protrusion amount point is set to a positive value, and the protrusion point is set in the direction that increases the amount of protrusion. In addition, if the sheet is uncoated paper or a sheet with a surface that is less likely to scratch, the protrusion amount point may be set to zero.

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 points set based on the sheet basis weight and the protrusion amount points set based on the surface coating and surface scratch susceptibility. 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 optimized for the sheets set in the storage tray 10.

Once the anti-floating member 13b has protruded a predetermined amount from the side fence 13, the gear drive motor 142 is driven to adjust the protruding angle of the anti-floating member 13b relative to the side fence 13, as shown in Figure 12(c).

By driving the gear drive motor 142, the rotating gear 141 rotates. This rotation of the rotating gear causes the protrusion amount change mechanism 240 to rotate 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, changing the protrusion angle of the lift-up suppression member 13b relative to the side fence 13.

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 host controller 101. Then, it drives the belt drive motor 242 in the set rotation direction and for the set drive time.

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.

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 considered positive, and the rotation direction of the belt drive motor 242 in which the tip is positioned below the horizontal direction is considered negative. When the total points are negative, the belt drive motor 242 is rotated counterclockwise in the figure, 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 figure, causing the lift-up suppression member 13b to protrude upward.

As shown in Table 2, when the basis weight of the sheet set in the storage tray 10 as indicated by its thickness information is high, the angle point for the lift suppression member 13b is set to a positive value, and the point is set so that the lift suppression member 13b protrudes upward from the side fence 13. When the basis weight is high, the paper is thick and stiff, so the pressure applied by the lift suppression member 13b to the sheet increases. Therefore, the angle point is set to a positive value, and the lift suppression member 13b is set to protrude upward from the side fence 13, preventing an increase in the pressure applied by the lift suppression member 13b to the sheet. This prevents poor feeding and scratches from occurring.

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 anti-floating member against the sheet is weak, the anti-floating member 13b may not be able to prevent the sheet from floating up. When the sheet set in the storage tray 10 is a low-basis-weight sheet, the angle point is set to a negative value, and the anti-floating member 13b is set to protrude downward.

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

On the other hand, if the sheet set in the storage tray 10 is uncoated paper, which is less likely to show scuff marks, or a sheet with a surface that is less likely to scratch and is less likely to show scuff marks, 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 for uncoated paper or a sheet with a surface that is less likely to scratch, the angle point may be set to zero.

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 total point: an angle point set based on the sheet basis weight and an angle point set based on the condition of the surface coating and the surface's susceptibility to scratches. If the total point is positive, the gear drive motor 142 is driven clockwise in the figure for the set drive time. This causes the lift-up suppression member 13b to protrude upward from the side fence at a specified protrusion angle. On the other hand, if the total point is negative, the gear drive motor 142 is driven counterclockwise in the figure for the set drive time. This causes the lift-up suppression member 13b to protrude downward from the side fence 13 at a specified protrusion angle. This allows the lift-up suppression member 13b to be set at the optimal protrusion angle for the sheets set in the storage tray 10.

The protrusion amount may be set based on the basis weight, and the protrusion angle may be set based on the sheet type and surface scratch susceptibility, or vice versa (the protrusion amount may be set based on the sheet type and surface scratch susceptibility, and the protrusion angle may be set based on the protrusion amount).

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 protruding 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. On the other hand, 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.

FIG. 13 is a diagram showing another example of the protrusion state changing device 40. As shown in FIG.
13, a protrusion angle changing mechanism 140 includes 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. The lift suppression member 13b is attached to the winding region of the drive belt 145 where the drive belt 145 is wound around the driven roller 145a.

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 that it can slide horizontally within a predetermined range. The protrusion amount change mechanism 240 has a pinion gear 244 that meshes with a horizontally extending rack gear provided on the underside of this holding member 243. This pinion gear 244 meshes with a drive gear 245 attached to the motor shaft of a gear drive motor 246.

When there are no more sheets on the sheet loading 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 protrudes from the side fence 13 rotates counterclockwise in the figure and is stored within the side fence 13, as shown in Figure 13(a). As a result, when setting a sheet on the sheet loading table 11, the lift suppression member 13b does not get in the way of the sheet setting, making it easy to set the sheet on the sheet loading table 11.

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

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

As shown in Figure 13(c), rotating the gear drive motor 246 clockwise in the figure moves the holding member 243 to the left in the figure. This causes the protrusion angle change mechanism 140 held by the holding member 243 to move 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 to move 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, rotating the gear drive motor 246 counterclockwise in the figure moves the lift-up suppression member 13b toward the side fence 13, reducing the amount of protrusion.

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 the optimal protrusion amount corresponding to the sheets set in the storage tray 10.

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 limited to this. 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 sheet 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 non-volatile memory of the control unit 66. The control unit 66 then obtains 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 obtained brand information from the non-volatile memory. The protrusion state change device 40 is then controlled to achieve the read-out protrusion state, thereby setting 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.

In the above description, both the protrusion amount and protrusion angle of the anti-floating 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. If only the protrusion amount of the anti-floating member 13b relative to the side fence 13 is changed based on the sheet set in the storage tray 10, only the protrusion amount change mechanism shown in Figure 12 is provided. By providing the protrusion amount change mechanism shown in Figure 12, the anti-floating member can be stored in the side fence when there is no sheet, and the protrusion amount can be changed to match the sheet.

On the other hand, if only the protrusion angle of the anti-floating 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 Figure 13 is provided. By providing the protrusion angle change mechanism shown in Figure 13, the anti-floating member 13b can be stored in the side fence 13 when there is no sheet, and the protrusion angle can be changed to match the sheet.

Floating suppression member 13b is also configured to be detachable from side fence 13. It is also possible to have multiple floating suppression members that are detachable from the side fence and have different protrusion amounts and protrusion angles from the side fence 13. When a user sets a stack of sheets on the storage tray 10, they remove floating suppression member 13b from the side fence 13. Then, after placing the stack of sheets on the sheet loading platform 11, they attach a floating suppression member corresponding to the sheets of the placed stack of sheets to the side fence. This configuration also allows the protruding state of the floating suppression member relative to the side fence 13 to be changed to a protruding state corresponding to the sheets being set.

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, so 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 aspect 1, the protrusion 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 in the sheet stacking section, the floating position restricting member can be set to a protrusion state in which the floating position restricting member protrudes a large amount from the sheet position restricting member or protrudes downward, as described above, so that the floating position restricting member can press the floating sheet more firmly. On the other hand, when a sheet with high stiffness is loaded in the sheet stacking section, the floating position restricting member can be set to a protrusion state in which the floating position restricting member protrudes a small amount from the sheet position restricting member or protrudes upward, as described above, so that the floating position restricting member can press the floating sheet less firmly.
In this way, in aspect 1, 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.

(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 restricting 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 restricting 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.

(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 .
As described in the embodiment, this allows the projection angle to be set so that when stiff sheets such as cardboard are loaded on a sheet stacking section such as the sheet loading table 11, the projection angle of the floating position restricting member such as the floating suppression member 13b projects upward from the sheet position restricting member such as the side fence 13. This makes it possible to suppress an increase in the pressing force of the floating position restricting member 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 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.

(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 restricting member such as the floating suppression member 13b relative to the sheet position restricting member such as the side fence 13 to be optimally set in accordance with 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.

(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, a feeding device according to any one of aspects 1 to 4 was used as the feeding device.

1: Image forming apparatus 10: Storage tray 11: Sheet placing table 12: Front blower 13: Side fence 13a: Discharge port 13b: Floating suppression member 13c: Opening 14: Side blower 14a: Side blower 15: Floating blower 16: Separation blower 17: Blower 19: Lifting device 20: Feeding unit 21: Suction belt 21a: Belt suction surface 25: End fence 40: Protrusion state change device 66: Control unit 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 : Holding member 244 : Pinion gear 245 : Drive gear 246 : Gear drive motor 300 : Sheet type determination device P : Sheet P1 : Top sheet Pt : Sheet stack

Patent No. 4544033

Claims (4)

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. 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. 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. 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;