JP7129026B2 - Sheet feeding device, image forming device, image forming system, and sheet processing device - Google Patents

Description

The present invention relates to a sheet feeding apparatus, an image forming apparatus, an image forming system, and a sheet processing apparatus for processing sheets.

Conventionally, it is built in or connected to a processing apparatus such as an electrophotographic or inkjet image forming apparatus, floats the uppermost sheet of a sheet bundle such as a sheet or prepreg, and feeds it by a conveying means such as an adsorption conveying unit. As a sheet feeding device for conveying (conveying), the following are known.

For example, Japanese Patent Application Laid-Open No. 2002-200002 describes a sheet feeding device (sheet feeding device) as follows.
A first reflective optical sensor (first reflective optical sensor) that detects the floating sheet (floating paper) in the upper (floating area) and multiple floating sheets (in the semi-floating area) located below it. and a second reflective optical sensor (second reflective optical sensor). Further, the sheet feeding apparatus controls the lifting means based on the combination of the output values of the reflection type optical sensors.

However, in the conventional sheet feeding apparatus, in the vicinity of the last when the number of sheets on the sheet stacking portion is small, the sheets may not be fed due to insufficient floating of the sheets.

In order to solve the above-described problems, the invention according to claim 1 provides an air blowing means for floating the upper sheets of a sheet bundle, a suction conveying means for sucking and conveying the floating sheets, and a stacking of the sheet bundle. a lifting means for lifting and lowering a sheet stacking unit; a first reflective optical sensor for detecting the density of floating sheets in a certain area; and a second reflective optical sensor for detecting a sheet bundle and a side surface of the sheet stacking unit; In the sheet feeding device that controls the lifting means based on the detection result of each reflective optical sensor, the side surface of the sheet stacking unit has both a detection area and a non-detection area, and the second reflective optical sensor is changed from the detection state to the non-detection state, the lifting means lifts the sheet stacking unit.

According to the present invention, it is possible to provide a sheet feeding apparatus capable of suppressing non-feeding of sheets due to insufficient floating of sheets near the last when the number of sheet bundles on the sheet stacking unit is small.

1 is a schematic configuration diagram of an image forming system according to an embodiment; FIG. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment; FIG. 1 is a schematic configuration diagram of a sheet feeding device according to an embodiment; FIG. FIG. 4 is a schematic perspective view of the vicinity of the sheet feeding tray of the sheet feeding device; FIG. 4 is a schematic cross-sectional view of the vicinity of the sheet feeding tray of the sheet feeding device; Explanatory drawing of a first side upper surface sensor and a second side upper surface sensor. FIG. 2 is a block diagram showing an example of a main configuration of a control system of the sheet feeding device; FIG. 4 is a schematic explanatory diagram of an elevating means of the sheet feeding device; FIG. 10 is an explanatory diagram of an example of up-and-down control of the sheet stacking table according to the detection result of the sheet detection sensor; FIG. 4 is an explanatory diagram of a suckable area by the sucking and conveying unit; FIG. 10 is an explanatory diagram of the positional relationship between the sheet stacking portion and the floating nozzle near the last; FIG. 4 is an explanatory diagram of a configuration of a sheet stacking unit that suppresses non-feeding of sheets; FIG. 5 is a control flow diagram of the up-and-down operation of the sheet stacking unit; FIG. 5 is an explanatory view of the position of the bottom plate of the sheet stacking portion near the last; FIG. 5 is an explanatory diagram of forced lifting of the sheet stacking unit;

An embodiment of a sheet feeding apparatus to which the present invention is applied will be described below.
FIG. 1 is a schematic configuration diagram of an image forming system 1 of this embodiment.
As shown in FIG. 1, the image forming system 1 includes an electrophotographic image forming apparatus 100 as image forming means for forming an image on a sheet, and a sheet feeding apparatus 200 for feeding the sheet to the image forming apparatus. I have. The sheet feeding device is provided on the side surface of the image forming apparatus 100 main body.

First, the overall configuration and operation of a printer to which the sheet feeding apparatus of the present embodiment can be applied and an image forming apparatus such as a copier having an equivalent image forming function will be described.
FIG. 2 is a schematic configuration diagram of the image forming apparatus 100 according to this embodiment.
This image forming apparatus 100 is a full-color printer that uses four color toners of yellow (Y), cyan (C), magenta (M), and black (K), and a full-color printer that has equivalent image forming functions. As shown in FIG. 2, four image forming units 101Y, 101M, 101C, and 101K for forming images with respective color toners are arranged side by side in the upper part of the apparatus main body.

Since the configuration and operation of each of the image forming units 101Y, M, C, and K are substantially the same, the image forming units will be explained here by omitting the symbols (Y, M, C, and K) indicating colors. . In the image forming unit 101, a charging device 103, a developing device 104, a cleaning device 105, and the like are arranged around a photosensitive drum 102 as an image carrier. An exposure unit 107 is arranged above the photosensitive drum 102 .

Below the four image forming units 101Y, 101M, 101C, and 101K, an intermediate transfer belt 108 is arranged around a plurality of support rollers. The intermediate transfer belt 108 is driven to run in the direction of arrow A by one of the support rollers being rotationally driven by the drive means. A transfer roller 106 as a primary transfer means is arranged so as to face the photosensitive drum 102 of each image forming unit 101 with the intermediate transfer belt 108 interposed therebetween.

In each image forming unit 101, the photoreceptor drum 102 is driven to rotate counterclockwise in the drawing, and the surface of the photoreceptor drum 102 is uniformly charged to a predetermined polarity by the charger 103. FIG. Then, the charged surface is irradiated with a light-modulated laser beam emitted from the exposure means 107 , thereby forming an electrostatic latent image on the photosensitive drum 102 . The formed electrostatic latent image is developed with toner applied from the developing device 104 and visualized as a toner image. The yellow, cyan, magenta, and black toner images formed by the image forming units 101 are transferred onto the intermediate transfer belt 108 so as to be sequentially superimposed.

On the other hand, a sheet feeding section 114 having a feeding tray 114a and a feeding tray 114b is provided in the lower portion of the apparatus main body. Sheets and sheets such as prepregs are fed from either the sheet feeding unit 114 or a sheet feeding device 200 connected to the image forming apparatus 100, which will be described later in detail. The fed sheet is conveyed in the direction of arrow B toward registration rollers 111 .

The sheet that has hit the registration roller 111 and is temporarily stopped is sent out from the registration roller 111 in timing with the toner image on the intermediate transfer belt 108, and the secondary transfer roller 109 and the intermediate transfer belt 108 contact each other. It is sent to the next transfer section. A voltage having a polarity opposite to the charged polarity of the toner is applied to the secondary transfer roller 109, thereby transferring the superimposed toner image (full-color image) on the intermediate transfer belt 108 onto the sheet. The sheet on which the toner image has been transferred is conveyed to the fixing device 113 by the conveying belt 112, and the toner is fixed on the sheet by the fixing device 113 by heat and pressure. The sheet on which the toner image has been fixed is discharged outside the machine as indicated by an arrow C and stacked on a discharge tray.

Here, in the case of single-sided printing and ejection of the back surface (face-down ejection), the sheet is ejected outside the apparatus as indicated by an arrow C through the sheet reversing unit 115, thereby turning the front and back of the sheet upside down. In the case of double-sided printing, the fixed sheet passes through the reversing section 116 and is conveyed again from the re-feeding path 117 toward the registration roller 111, and the toner image is transferred from the intermediate transfer belt 108 to the back surface of the sheet. After the toner image has been transferred, the sheet is fixed by the fixing device 113, and is sent from the fixing device 113 as indicated by arrow C in the same manner as single-sided printing, or as indicated by arrow C via the sheet reversing section 115. It is ejected and loaded onto the ejection tray. Switching claws 118 and 119 for switching the sheet conveying direction are appropriately arranged on the sheet conveying path.

In the case of monochrome printing, in the image forming apparatus 100 of the present embodiment, a toner image is formed using only the black (K) image forming unit 101K, and the toner image is transferred onto a sheet via the intermediate transfer belt 108. to transcribe. The handling of the sheet after fixing the toner image is the same as in the case of full-color printing.

Further, on the upper surface of the apparatus main body, a toner bottle setting section 120 is provided in which toner bottles 121 of respective colors containing toner to be supplied to the developing device 104 of each image forming unit 101 are set. An operation unit 124 having a display unit 122 and an operation panel 123 is also provided on the upper surface of the apparatus main body.
A sheet loading section D from a sheet feeding device 200 (see FIG. 3), which will be described later, is provided on the right side surface of the image forming apparatus 100 shown in FIG. In the sheet carrying-in portion D, an opening 125 for receiving sheets and a conveying means 126 for conveying sheets are provided.

FIG. 3 is a schematic explanatory diagram of the sheet feeding device 200 of this embodiment connected to the side surface of the device main body.
The sheet feeding device 200 includes two upper and lower feeding trays 10 . Each feed tray 10 includes a sheet stacking portion 11 that stacks a bundle of sheets S thereon. In this embodiment, each feed tray 10 can accommodate a maximum of about 2500 sheets. Above each feed tray 10, a suction transport unit 20 as a transport unit that adsorbs and transports the sheet S stacked on the feed tray 10 is arranged. The suction transport unit 20 includes a suction belt 21 and a suction device 23, which are transport members. That is, the sheet feeding device 200 is a so-called air-pick sheet feeding device.

In each feeding tray 10, a sheet detection sensor 31 having two reflective optical sensors detects the side surfaces of a plurality of sheets on the upper portion of the sheet stack stacked on the sheet stacking section 11, and a sheet detection sensor 31 having two reflective optical sensors detects the side surface of the sheets, and detects the output value of the sheet according to the output value. In addition, sheet surface detection control is employed to move the sheet stacking unit 11 up and down.
The sheet detection sensor 31 includes a first side upper surface sensor 31a and a second side upper surface sensor 31b, which will be described later.
Sheets stacked on the lower feeding tray 10 pass through the lower conveying path 82 and are conveyed to the main body of the image forming apparatus 100 by the exit roller pair 80 . On the other hand, the sheet stacked on the upper feeding tray 10 is conveyed to the main body of the image forming apparatus 100 by the exit roller pair 80 through the upper conveying 81 .

FIG. 4 is a schematic perspective view of the vicinity of the sheet feeding tray 10 of the sheet feeding device 200. FIG.
The suction belt 21 of the suction transport unit 20 is stretched by two tension rollers 22a and 22b, and suction holes penetrating from the surface side to the back side of the suction belt 21 are provided throughout the circumferential direction. . 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. It acts to let

Further, the feeding tray 10 is provided with an air blower 17 which is air blowing means for blowing air against the sheets S on the upper portion of the sheet bundle Sb. This blower 17 has a front blower 12 and a pair of side blowers 13 .
The front air blower 12 blows air toward the top end of the sheet bundle Sb (the downstream end in the feeding direction). The front blower 12 includes a floating nozzle that guides air in a direction to float the upper sheet of the sheet bundle Sb, a separation nozzle that guides air in a direction to separate the uppermost floated sheet and the other sheets, and , a blower fan 15 for blowing air into each of the floating nozzle and the separation nozzle. Among these nozzles, the air blown from the floating nozzle in the direction indicated by the arrow a1 in the drawing is called floating air, and the air blown from the separation nozzle in the direction indicated by the arrow a2 in the drawing is called separation air. The floating air and the separation air are discharged from a portion facing the upper tip (the downstream end in the feeding direction) of the sheet bundle Sb, and are blown to the upper tip (the downstream end in the feeding direction) of the sheet bundle Sb. .

Each of the pair of side blowers 13 is provided with a blower fan 14 on the side fence, and blows air toward the upper side surface of the sheet stack Sb in the direction indicated by the arrow b in the figure. The side air blower 13 is provided with a side floating nozzle that guides air in the direction in which the sheet bundle Sb is loosened and floated. call. The side air is discharged from a discharge port provided at a portion of each side blower 13 facing the upper portion of the sheet bundle Sb, and is blown to the side surface of the upper portion of the sheet bundle Sb. Air blown from the front blower 12 and the outlets of the pair of side blowers floats the upper sheets of the sheet bundle Sb.
Further, the feed tray 10 is provided with an end fence 25 for aligning the rear ends of the sheet bundles Sb stacked on the sheet stacking portion 11 .

FIG. 5 is a schematic cross-sectional view of the vicinity of the sheet feeding tray 10 of the sheet feeding device 200. As shown in FIG.
Further, a conveying roller pair 8, which is a downstream conveying member, is arranged on the downstream side in the conveying direction with respect to the adsorption belt 21, and the sheet bundle Sb is separated from the sheet bundle Sb, conveyed by the adsorption belt 21, and between the two rollers. The sheet S that has arrived is further conveyed toward the downstream side.
Further, as shown in FIG. 5, the above-described sheet detection sensor 31 is provided along the sheet stacking direction.
Further, in this embodiment, the sheet detection sensor 31 includes the first side upper surface sensor 31a and the second side upper surface sensor 31b as described above. The sheet detection sensor 31 is a reflective optical sensor and includes a light-emitting element and a light-receiving element.
Further, the front blower 12 is provided with a blower fan 15, a floating nozzle, a separation nozzle, and a blower duct 16 for guiding air to these nozzles.

Next, the sheet detection sensor 31 and the elevation control of the sheet stacking unit 11 will be described with reference to the drawings.
FIG. 6 is an explanatory diagram of the first side upper surface sensor 31a and the second side upper surface sensor 31b.
The first side upper surface sensor 31a and the second side upper surface sensor 31b shown in FIG. 6 are selectively used depending on whether the sheet is being fed or not. It is used in the floating state, that is, during paper feeding. On the other hand, the second side upper surface sensor 31b detects the side surface of the sheet bundle Sb in the non-floating state.
The first side upper surface sensor 31a is set to detect a position 12 [mm] below the suction surface of the suction belt 21, and the second side upper surface sensor 31b is set to detect a position 18 [mm] below. there is

FIG. 7 is a block diagram showing an example of the main configuration of the control system of the sheet feeding device 200. As shown in FIG.
As shown in FIG. 7, the sheet control unit 18 as the control means of the sheet feeding device 200 is connected to the upper surface sensors 31a and 31b on each side of the feeding tray 10. As shown in FIG. Also, a blower fan 15 that blows air into the floating nozzle and separation nozzle of the front blower 12, a blower fan 14 that blows air toward the side floating nozzle of the side blower 13, and a suction fan 24 of the suction device 23. It is connected. An elevating motor 19 included in elevating means for elevating the sheet stacking section 11 is also connected.
By providing the sheet control unit 18 in this way, even if the image forming apparatus 100 is connected to the image forming apparatus 100 that cannot directly control the elevation motor 19 for raising and lowering the sheet stacking unit 11, the sheet can be fed at an appropriate timing. It is possible to provide the sheet feeding apparatus 200 capable of

FIG. 8 is a schematic explanatory diagram of the lifting means of the sheet feeding device.
As shown in FIG. 8 , the sheet stacking portion 11 is connected to a wire 292 , and the wire 292 is wound up by rotating the pulley 291 , thereby horizontally raising the sheet stacking portion 11 . The pulley 291 is connected to the drive shaft of the lift motor 19 via a gear train, and the wire 292 is wound by rotating the drive shaft of the lift motor 19 .

FIG. 9 is an explanatory diagram of an example of elevation control of the sheet stacking unit 11 according to the detection result of the sheet detection sensor 31. As shown in FIG.
As shown in FIG. 9, from the output value of the first side upper surface sensor 31a, the sheet control unit 18 detects the sheet density (whether the sheets exist densely or sparsely) in a certain area in front of the sensor. is doing. Then, when the number of sheets decreases due to the feeding operation and the density of the floating sheets in the monitoring area D1 becomes less dense (=non-detected) than a preset threshold value, the sheet control unit 18 moves the sheet stacking unit by the lifting means. Raise 11.

Next, in the vicinity of the last when the number of sheets on the sheet stacking unit 11 is small, the reason why the sheets are not fed due to insufficient floating of the sheets will be described with reference to the drawings.
FIG. 10 is an explanatory diagram of the suckable area E1 by the suction transport unit 20. As shown in FIG.
By controlling the position of the sheet stacking unit 11 according to the detection result of the first side upper surface sensor 31a, it is necessary to position the uppermost sheet of the floating sheet bundle in the suctionable area E1 shown in FIG. Here, the suctionable area E1 is an area where the suction belt 21 of the suction conveyance unit 20 can suction the sheet.
On the other hand, if the uppermost sheet is separated from the suctionable area E1, the suction conveyance unit 20 cannot absorb the uppermost sheet, and sheet non-feeding, so-called non-feeding, occurs. Hereinafter, the area where the paper failure occurs will be referred to as a paper failure occurrence area E2.

11A and 11B are explanatory diagrams of the positional relationship between the sheet stacking unit 11 and the floating nozzle 201 near the last. FIG. It is cross-sectional explanatory drawing of the neighborhood.
When the number of sheet bundles stacked on the sheet stacking portion 11 decreases and the sheet stack on the sheet stacking portion 11 is near the last, as shown in FIGS. The bottom plate 207 rises to a position where it blocks the air from the front blower 12, which is an air blower. For this reason, the air is less likely to hit the sheet and the sheet is less likely to float, so that even if there is a floating sheet in the monitoring area D1 of the first side upper surface sensor 31a, there is a problem that the sheet cannot float to the suctionable area E1.

FIG. 12 is an explanatory diagram of the configuration of the sheet stacking unit 11 that suppresses non-feeding of sheets.
While the sheets are being fed, as the sheets stacked on the sheet stacking portion 11 are fed, the detection surfaces provided on the side surfaces of the sheet stacking portion 11 that are detected by the side upper surface sensors 31a and 31b ( Hereinafter, the side upper surface sensor detection surface 204 is appropriately referred to as 204.) faces the side upper surface sensors 31a and 31b and rises. The side upper surface sensor detection surface 204 is made of a sheet metal material that can be detected by the respective side upper surface sensors 31a and 31b.

A non-detection area 205 that does not reflect the light from the light emitting portions of the upper side sensors 31 a and 31 b is provided on the upper side sensor detection surface 204 .
The distance (length) of the non-detection area 205 in the height direction (the direction along the vertical direction of the sheet stacking unit 11) is such that the floating sheet can be sucked from the position where the sheet stacking unit 11 blocks the air. It is the distance A to the position (experimental value obtained from the evaluation) that can float to the area E1. As shown in FIG. 12, a suede material (member) 203 as a reflection reducing material for reducing reflection of light from the light emitting portions of the side upper surface sensors 31a and 31b is attached (provided) to the side upper surface sensor detection surface 204. Thus, the non-detection regions 205 of the side upper surface sensors 31a and 31b are formed. Forming the non-detection region 205 by adhering the suede material 203 in this manner can increase the accuracy of detecting the position of the sheet stacking unit in the height direction (accuracy of lifting operation) with a simple configuration.
Here, the detection region 206 is the sheet metal portion of the side upper surface sensor detection surface 204 to which the suede material 203 is not attached and which reflects light. In addition to attaching the suede material 203, the reflection reducing material may include attaching a sheet or film to prevent reflection of light, or coating a desired range of the side upper surface sensor detection surface 204 with such a material. A simple configuration is also acceptable.

Next, using the sheet stacking unit 11 provided with the non-detection area 205 as described above, the flow of control when performing the sheet feeding operation, the position of the bottom plate 207 of the sheet stacking unit 11 near the last, and A forced lifting operation of the sheet stacking portion 11 will be described.
FIG. 13 is a control flow chart of the lifting operation of the sheet stacking section 11, and FIG. 14 is an explanatory view of the position of the bottom plate 207 of the sheet stacking section 11 near the last. 15A and 15B are explanatory diagrams of the forcible lifting of the sheet stacking unit 11. FIG. 15A is an explanatory diagram of the forced lifting start position, and FIG. 15B is an explanatory diagram of the forced lifting end position.
During sheet feeding, normally, only the state of the first side upper surface sensor 31a is monitored to control the lifting operation of the sheet stacking section 11. FIG.

However, when the remaining amount of sheets calculated by the remaining amount detecting means for detecting the remaining amount of sheets stacked on the sheet stacking section 11 becomes equal to or less than a certain threshold value (for example, 5% or less), the first side upper surface sensor 31a is monitored. At the same time, the second side upper surface sensor 31b is also monitored. Then, when any one of the side upper surface sensors 31a and 31b is non-detected, control is performed to raise the sheet stacking section 11 (see FIG. 13).
For example, when the remaining amount of sheets becomes 5% or less, the sheet stacking portion 11 rises to the height of the second side upper surface sensor 31b. The side surface sensor sensing surface 204 can be monitored (see FIG. 15).
By configuring in this way, it is possible to further enhance the effect of suppressing non-feeding of the sheets S due to insufficient floating of the sheets S near the last when the sheet bundle Sb on the sheet stacking portion 11 is small. .

As an example of a specific control flow, as shown in the flow chart of FIG. 13, in the control of the sheet feeding operation, first, the upper side sensors 31a and 31b detect the sheet or the upper side sensor detection surface 204 (hereinafter referred to as appropriate). , is called a detection target) is started (S101). After starting the monitoring by the upper side sensors 31a and 31b in this way, the feeding of the sheet is started (S102).
Then, it is determined whether or not the first side upper surface sensor 31a has detected the detection target (S103). It is determined whether or not (S104). On the other hand, if the detection target is not detected (No in S103), the sheet stacking unit 11 is raised (S106).

When it is determined whether or not the sheet remaining amount is 5% or less (S104) and it is determined that the sheet remaining amount is 5% or less (Yes in S104), the second side upper surface sensor 31b detects the detection target. It is determined whether or not it has been detected (S105). On the other hand, if this determination is negative, that is, if it is determined that the sheet remaining amount exceeds 5[%] (No in S104), it is determined whether or not the first side upper surface sensor 31a has detected the detection target. Return (S103).
In determining whether or not the second side upper surface sensor 31b has detected the detection target (S105), if it is determined that the detection target has been detected (Yes in S105), whether the first side upper surface sensor 31a has detected the detection target Returning to the determination of whether or not (S103). On the other hand, if the detection target is not detected (No in S105), the sheet stacking section 11 is raised (S106).

Then, the sheet stacking unit 11 is lifted (S106), and when it is lifted by a certain amount: X [mm] (S107), it is determined whether or not the sheet feeding operation continues (S108).
In this determination (S108), if it is determined that the sheet feeding operation continues (Yes in S108), the process returns to determining whether or not the first side upper surface sensor 31a has detected the detection target (S103). On the other hand, if it is determined that the sheet feeding operation has not continued, that is, has ended (No in S108), monitoring by the upper surface sensors 31a and 31b on each side is completed (S109), and the sheet feeding operation is controlled. finish.
Here, the remaining amount of sheets detecting means counts the number of pulses of an elevating motor, which is the elevating means of the sheet stacking section 11, from a certain starting point. Calculates the sheet remaining amount.

With the above-described configuration, when the sheet stacking unit 11 rises to the position where it blocks the air flow path as shown in FIG. At 205 , the sheet stacking unit 11 starts to rise when the detection is not performed.
Then, as shown in FIG. 15B, the sheet stacking unit 11 is lifted to a position (experimental value obtained from evaluation) where the floating sheet can be lifted to the suctionable area E1. When the sheet stacking unit 11 rises in this way, the detection position of the second side upper surface sensor 31b becomes the detection area 206 under the suede material 203 of the side upper surface sensor detection surface 204, and the sheet stacking unit 11 is thus raised.
In this control, the lift start position (the position where the sheet stacking portion 11 blocks the air flow path) and the lift completion position (the position where the floating sheet can float in the suctionable area E1) are determined by the sheet metal and the suede material forming the sheet stacking portion 11. 203 can be controlled. By controlling in this manner, position control with higher accuracy than the position control controlled by the remaining amount detection means can be performed.

Further, control of the lifting means for lifting and lowering the sheet stacking section 11 may be switched according to a combination of detection states of the first side upper surface sensor 31a and the second side upper surface sensor 31b.
Normally, the sheet stacking unit 11 is lifted by repeating the lift by a predetermined specified step amount until a predetermined condition is satisfied. That is, the larger the specified step amount, the larger the amount that can be raised at one time, but the accuracy at the time of stop deteriorates.
Therefore, in the sheet feeding apparatus 200 of the present embodiment, the specified step amount (X1>X3>X2) when controlling the lifting means is switched (selectively used) according to the combination of the detection states of the upper side sensors 31a and 31b. ) can also be configured.
By switching in this manner, it is possible to provide the sheet feeding apparatus 200 capable of feeding the floated sheet S effectively at an appropriate timing.

There are four combinations of detection states of the upper surface sensors 31a and 31b, that is, combinations of "detection" and "non-detection" of the upper surface sensors 31a and 31b.
Table 1 shows examples of combinations.
Table 1 shows an example of the control content according to the combination of detection states of the side upper surface sensors 31a and 31b and the specified step amount when raising.

In the condition of "combination 1" shown in Table 1, the detection states of both the first side upper surface sensor 31a and the second side upper surface sensor 31b are "detected", and the first side upper surface sensor 31a detects a floating sheet with sufficient density ( (not floating) is detected, and the second side upper surface sensor 31b detects a sheet bundle. Therefore, it is determined that there is no urgent need to lift the sheet stacking unit 11, and the sheet stacking unit 11 is not lifted.
The condition of "Combination 2" shown in Table 1 is that the detection state of the first side upper surface sensor 31a is "non-detected" (=the floating sheet is sparse) and the detection state of the second side upper surface sensor 31b is "detected". . In this combination, when the floating sheets are sparse, the first side upper surface sensor 31a does not detect, and the second side upper surface sensor 31b detects the sheet stack. Therefore, the sheet must be supplied to the suckable area E1 as quickly as possible, and X1 [mm], which has the largest step amount, is applied.

In both the conditions of “Combination 3” and “Combination 4” shown in Table 1, the detection state of the second side upper surface sensor 31b is “non-detection”, and the non-detection area 205 (suede material 203) of the sheet stacking section 11 is likely to be detected. In particular, in "combination 4", unlike "combination 3" in which the first side upper surface sensor 31a is "detected", the first side upper surface sensor 31a is also "non-detected" (=the floating sheet is sparse). Then, when forcibly raised, stopping accuracy of the forced raising end position is required, so in "combination 3" and "combination 4", X2 or X3 [mm], which is finer than X1 [mm], is used. Especially in "combination 4", since stopping accuracy is required, and the first side upper surface sensor 31a is not detected (= the floating sheet is sparse), either stopping accuracy or rising speed where X1 > X3 > X2 Apply an intermediate step amount that can also be used for
By configuring as described above, according to the density state of the floating sheets in the floating area and the semi-floating area and the position of the sheet stacking unit 11, the lifting speed when raising the sheet stacking unit 11 and the lifting operation are stopped. It is possible to make it compatible with the stopping accuracy when doing.

The embodiment has been described above with reference to the drawings, but the specific configuration is not limited to the configuration including the sheet feeding device 200 of the embodiment described above, and is within the scope of the gist. You may change the design of
For example, in the present embodiment, the sheet feeding device 200 connected to the electrophotographic image forming apparatus 100 has been described. It can also be applied to things.
Further, the connected or built-in device is not limited to the image forming device, and for example, a sheet folding device that performs folding processing on a sheet, a sheet inspection device that performs inspection processing on a sheet or a processed sheet, or the like. It can also be applied to an apparatus for applying

Also, the image forming system 1 including the image forming apparatus 100 and the sheet feeding device 200 has been described. It is also applicable to sheet folding systems with
The sheet includes paper, coated paper, label paper, OHP sheet, film, prepreg, and the like.
Here, prepreg is mainly used as a material for laminates and multilayer printed wiring boards. For example, a long base material such as glass cloth, paper, non-woven fabric, or aramid cloth is continuously impregnated with a resin varnish mainly composed of a thermosetting resin such as epoxy resin or polyimide resin, dried by heating, and then cut. In other words, it is processed into a sheet shape (sheet material).

What has been described above is only an example, and each of the following aspects has a unique effect.
(Aspect A)
Blowing means such as a front blowing device 12 that floats sheets such as the upper sheet S of a sheet bundle such as the sheet bundle Sb, conveying means such as an adsorption conveying unit 20 that conveys the floated sheets, and sheets on which the sheet bundle is stacked. A lifting means having an elevating motor 19 for lifting and lowering a sheet stacking portion such as the stacking portion 11, a first reflective optical sensor such as a first side upper surface sensor 31a for detecting a floating sheet, a sheet bundle and the sheet stacking portion. and a second reflective optical sensor such as a second side upper surface sensor 31b for detecting a side surface such as the side upper surface sensor detection surface 204, and a sheet feeding device for controlling the lifting means based on the detection result of each reflective optical sensor. In a sheet feeding device such as the feeding device 200, the side surface of the sheet stacking portion has both a detection region such as a detection region 206 and a non-detection region such as a non-detection region 205, and the second reflective optical sensor is The sheet stacking unit is lifted by the elevating means when the detection state changes to the non-detection state.

According to this configuration, since the surface to be detected by the sensor of the sheet stacking portion has both the detection region and the non-detection region, the sheet stacking portion is positioned in the air flow path of the air blowing means, and the air hardly hits the floating sheet. The detection result of the second reflective optical sensor can be configured to change from detection to non-detection when the second reflective optical sensor rises to the position where the In other words, it is possible to detect that the sheet stacking portion is located in the air flow path of the air blowing means and that the air is less likely to hit the floating sheet. As a result, even if the sheet stacking surface is near the last, which is located above the detection range of the second reflective optical sensor, the floating sheet air may easily hit or may not hit easily. It is possible to perform control suitable for the configuration of the sheet feeding device.

Here, when the sheet stacking surface is near the last position above the detection range of the second reflective optical sensor, based on a combination of the detection results of the respective reflective optical sensors, the amount of rising step is changed when the sheet stacking surface is raised. Examples of such cases include the following.
When the detection area of the sheet stacking unit is detected by the second reflective optical sensor, if the first reflective optical sensor is detecting, nothing is done (stopped), and the first reflective optical sensor is non-detecting. In this case, the sheet stacking portion is lifted with the smallest lifting step amount.
On the other hand, when the second reflective optical sensor detects the non-detection area of the sheet stacking portion and becomes non-detectable, if the first reflective optical sensor is non-detectable, the sheet is raised by an intermediate step amount. , when the first reflective optical sensor is detecting, it is raised by the largest step amount.
This control can be adjusted according to the range of the detection area and the non-detection area of the sheet stacking section. It can be configured to switch at a position where it becomes difficult.

Then, when it is detected that it is difficult for air to hit the floating sheet, the lifting means is controlled in accordance with the combination of the detection results of the reflective optical sensors to raise the sheet stacking section, and the floating sheet can be sucked into the area E1 or the like. It is also possible to control more appropriately than before up to the suctionable area of .
Therefore, it is possible to provide a sheet feeding apparatus capable of suppressing non-feeding of sheets due to insufficient floating of sheets near the last when the number of sheet bundles on the sheet stacking portion is small.

(Aspect B)
In (Aspect A), control means such as a seat control unit 18 for controlling the lifting means based on detection results such as detection/non-detection of the first reflective optical sensor and the second reflective optical sensor are provided. It is characterized by
According to this, it is possible to provide a sheet feeding apparatus capable of feeding sheets at appropriate timing even when connected to a device that cannot directly control the elevating means for elevating the sheet stacking section.

(Aspect C)
In (Mode A) or (Mode B), the It is characterized in that the presence or absence of the lifting operation of the lifting means and the amount of lifting such as specified step amounts X1, X2, and X3 of the sheet stacking portion are changed by switching.
According to this, it is possible to provide a sheet feeding device capable of feeding effectively floated sheets at appropriate timing.

(Aspect D)
In any one of (Aspect A) to (Aspect C), when either the first reflective optical sensor or the second reflective optical sensor fails to detect, The lifting operation is performed when the remaining amount of the sheet bundle stacked on the sheet stacking unit becomes equal to or less than a certain threshold such as 5[%].
According to this, it is possible to further enhance the effect of suppressing non-feeding of sheets due to insufficient floating of sheets near the last when the number of sheet bundles on the sheet stacking unit is small.

(Aspect E)
In any one of (Aspect A) to (Aspect D), a reflection reducing material such as suede material 203 constituting the non-detection area is provided on the side surface of the sheet stacking portion.
According to this, it is possible to improve the accuracy of position detection in the height direction of the sheet stacking unit (accuracy of lifting operation) with a simple configuration.

(Aspect F)
(Aspect E) is characterized in that the reflection reducing material is a suede member such as the suede material 203 .
According to this, it is possible to increase the accuracy of detecting the position of the sheet stacking portion in the height direction (accuracy of the lifting operation) with a simple configuration at a low cost.

(Aspect G)
In any one of (Aspect A) to (Aspect F), the first reflective optical sensor does not detect a step amount such as a specified step amount for raising the sheet stacking unit, and the second reflective optical sensor detects X1 when the first reflective optical sensor is detecting and the second reflective optical sensor is non-detecting, X2 when the first reflective optical sensor is non-detecting and the second reflecting It is characterized by satisfying the relationship of X1>X3>X2, where X3 is assumed when the optical sensor is non-detecting.
According to this, according to the density state of the floating sheets in the floating area and the semi-floating area and the position of the sheet stacking unit 11, the speed at which the sheet stacking unit 11 is raised and the speed at which the lifting operation is stopped are determined. It is possible to achieve both accuracy and accuracy.

(Aspect H)
In an image forming apparatus such as the image forming apparatus 100 that forms an image on a sheet such as a sheet S that is separated and fed from a sheet bundle such as a sheet bundle Sb, as a means for separating and feeding a sheet from the sheet bundle (Aspect A ) to (Aspect G).
According to this, it is possible to provide an image forming apparatus that can achieve the same effect as the sheet feeding apparatus according to any one of (Aspect A) to (Aspect G).

(Aspect I)
An image forming system 1 including an image forming apparatus such as an image forming apparatus 100 and a sheet feeding means for feeding a sheet such as a sheet S separated from a sheet bundle such as a sheet bundle Sb to the image forming apparatus. The forming system is characterized by comprising a sheet feeding device such as the sheet feeding device 200 according to any one of (Aspect A) to (Aspect G) as the sheet feeding means.
According to this, it is possible to provide an image forming system that can achieve the same effect as the sheet feeding device according to any one of (Aspect A) to (Aspect G).

(Aspect J)
In a sheet processing apparatus such as a sheet folding apparatus that performs processing such as folding on a sheet such as a sheet S separated and fed from a sheet bundle such as a sheet bundle Sb, as means for separating and feeding a sheet from the sheet bundle, It is characterized by including a sheet feeding device such as the sheet feeding device 200 according to any one of A) to (Mode G).
According to this, it is possible to provide a sheet processing apparatus that can achieve the same effect as the sheet feeding apparatus according to any one of (Aspect A) to (Aspect G).

1 image forming system 11 sheet stacker 12 front blower 13 side blower 14, 15 blower fan 16 blower duct 17 blower 20 suction conveyance unit 21 suction belt 23 suction device 31 sheet detection sensor 31a first side upper surface sensor 31b second Side upper surface sensor 100 Image forming apparatus 200 Sheet feeding device 201 Floating nozzle 203 Suede material 204 Side upper surface sensor detection surface 205 Non-detection area 206 Detection area 207 Bottom plate D1 Monitoring area (first side upper surface sensor)
D2 Density detection area (second side upper surface sensor)
E1 suckable area S sheet Sb sheet bundle

JP 2017-105563 A

Claims (10)

A blowing means for floating the upper sheets of the sheet bundle, an adsorption conveying means for sucking and conveying the floated sheets, an elevating means for raising and lowering the sheet stacking section on which the sheet bundle is stacked, and the density of the floating sheets in a certain area is adjusted. A sheet comprising a first reflective optical sensor for detecting a sheet stack and a second reflective optical sensor for detecting a side surface of the sheet stacking unit, and for controlling the lifting means based on detection results of the respective reflective optical sensors. in the feeding device,
The side surface of the sheet stacking unit has both a detection area and a non-detection area, and when the second reflective optical sensor changes from the detection state to the non-detection state, the sheet stacking unit is lifted by the elevating means. A sheet feeding device characterized by: The sheet feeding device according to claim 1,
A sheet feeding apparatus, comprising: control means for controlling said elevating means based on a combination of detection results of said first reflective optical sensor and said second reflective optical sensor. In the sheet feeding device according to claim 1 or 2,
Based on a combination of detection results of the first reflective optical sensor and the second reflective optical sensor, presence or absence of a lifting operation of the lifting means and an amount of lifting of the sheet stacking unit are changed. sheet feeder. The sheet feeding device according to any one of claims 1 to 3,
When either the first reflective optical sensor or the second reflective optical sensor fails to detect, the lifting operation of the sheet stacking unit by the elevating means is controlled by the sheet bundle stacked on the sheet stacking unit. A sheet feeding device characterized in that it is executed when the remaining amount of the sheet falls below a certain threshold value. The sheet feeding device according to any one of claims 1 to 4,
A sheet feeding apparatus according to claim 1, wherein a reflection reducing material forming the non-detection area is provided on a side surface of the sheet stacking portion. In the sheet feeding device according to claim 5,
The sheet feeding device, wherein the reflection reducing material is a suede member. The sheet feeding device according to any one of claims 1 to 6,
The step amount for raising the sheet stacking unit is
X1 when the first reflective optical sensor is non-detecting and the second reflective optical sensor is detecting,
X2 when the first reflective optical sensor is detecting and the second reflective optical sensor is non-detecting;
X3 when the first reflective optical sensor is non-detecting and the second reflective optical sensor is non-detecting;
, a sheet feeding device that satisfies a relationship of X1>X3>X2. In an image forming apparatus that forms an image on a sheet separated and fed from a sheet bundle,
An image forming apparatus comprising the sheet feeding device according to any one of claims 1 to 7 as means for separating and feeding a sheet from the sheet bundle. In an image forming system comprising an image forming apparatus and sheet feeding means for feeding sheets separated from a sheet bundle to the image forming apparatus,
An image forming system comprising the sheet feeding device according to any one of claims 1 to 7 as the sheet feeding means. In a sheet processing apparatus that processes sheets separated and fed from a sheet bundle,
A sheet processing apparatus comprising the sheet feeding device according to any one of claims 1 to 7 as means for separating and feeding a sheet from the sheet bundle.

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