JP2017137144A - Paper feeding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper feeding device capable of preventing paper feeding failure by aligning sheets on a loading tray surely by a movable regulation plate of the paper feeding device.SOLUTION: A paper feeding device includes: a loading tray 32 for loading envelopes; a delivery roller 40 for coming into contact with the envelopes loaded on the loading tray 32 and for delivering them; and a paper feeding roller 41 for feeding the delivered envelopes. The paper feeding device also includes: loading amount detection means 61 for detecting a loading amount of the envelopes on the loading tray 32; and change means for changing a load imparted on the upper surface of the envelopes on the loading tray 32 according to the loading amount of the envelopes detected by the loading amount detection means 61.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a sheet feeding device that feeds a sheet to an image forming apparatus such as a copying machine or a printer.

  2. Description of the Related Art Conventionally, a sheet feeding device that feeds a sheet to an image forming unit of an image forming apparatus such as a copying machine or a printer is known. The sheet feeding device includes a feeding roller that feeds out the sheets on the stacking tray, a separation mechanism that separates the sheets into one sheet, and a conveyance roller pair that conveys the separated sheets toward the image forming apparatus. Is provided. The sheets on the stacking tray are guided to the image forming apparatus along the sheet feeding path by the feeding roller, the separating unit, and the conveying roller pair.

  Among these types of paper feeders, in an apparatus that handles a large number of sheets, a stackable tray that can be raised and lowered is provided by raising the stacking tray and bringing the uppermost surface of the sheet on the stacking tray into contact with the peripheral surface of the feeding roller. Devices equipped are known. In the sheet feeding device having the stacking tray, the stacking tray is raised by a motor so that the uppermost surface of the sheet is brought into contact with the feeding roller, and the sheet is fed at a position where the feeding roller is pushed up by a predetermined amount (feeding position). is there. The sheet feeder is provided with sheet upper surface detecting means for detecting that the uppermost surface of the sheet placed on the stacking tray has reached a predetermined feeding position, and the sheet upper surface detecting means is provided on the upper surface of the sheet. When this is detected, the motor is controlled to stop.

  Here, in recent paper feeders, some sheets handle envelopes other than plain paper. In such a paper feeder that can handle envelopes, since the loaded envelopes are swollen, the pressure contact force between the envelope and the feeding roller fluctuates when the envelope is fed out, and the feeding failure such as non-feeding or skewing of the envelope Had occurred.

  In order to solve such a problem, Patent Document 1 proposes an apparatus in which a constant load is applied to the uppermost surface of the envelope by a feeding roller or a pushing member to reduce the swelling of the envelope and to feed the envelope. .

JP 2002-249234 A

  However, in the apparatus disclosed in Patent Document 1, since the load applied to the envelope is constant, the contact between the envelope upper surface and the feeding roller when the envelope stacking amount (the number of stacked sheets) is small or large. A difference occurs in the pressure, resulting in a feeding failure. In other words, if the load applied to the envelope is small, non-feeding or skew will occur when the envelope load (the number of sheets) is large, and if the load applied to the envelope is large, the envelope load (the number of sheets) is small However, there is a problem that traces of pressing of the feeding roller are generated on the double feed or the sheet.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a paper feeding device capable of feeding out an envelope regardless of the amount of envelopes loaded.

  In order to achieve the above object, the present invention includes a stacking tray on which envelopes are stacked, a feeding roller that feeds out envelopes in contact with the envelopes stacked on the stacking tray, and a paper feeding roller that feeds the fed envelopes. In the paper feeding device provided, a loading amount detecting means for detecting a loading amount of the envelope of the loading tray, and an upper surface of the envelope on the loading tray according to the loading amount of the envelope detected by the loading amount detection means And changing means for changing the load to be provided.

  According to the present invention, the load applied to the upper surface of the envelope on the stacking tray is changed according to the load amount of the envelope, so that variation in contact pressure between the feeding roller and the upper surface of the envelope due to the load amount can be suppressed, It becomes possible to reduce the feeding failure of the envelope.

1 is a diagram illustrating an overall configuration of an image forming system including a sheet feeding device according to the present invention. It is sectional drawing which shows the paper feeder which concerns on this invention. It is a perspective view which shows the storage of the paper feeder which concerns on this invention. It is a conceptual diagram which shows the control system of the paper feeder which concerns on this invention. It is a flowchart figure which shows the raising operation | movement of a stacking tray at the time of selecting for envelopes in the paper feeder which concerns on this invention. It is a state figure which shows the raising state of the stacking tray of the paper feeder which concerns on this invention. FIG. 10 is a state diagram illustrating a modified example of the paper feeding device according to the present invention.

  FIG. 1 is a diagram illustrating an overall configuration of an image forming system including a sheet feeding device. As shown in the figure, an image forming system includes an image forming apparatus 1 that prints an image on a sheet, an original reading apparatus 2 that reads an original, an original feeding apparatus 3 that conveys a sheet to a reading unit of the original reading apparatus 2, and an image forming system. A sheet feeding device 4 that supplies sheets to the apparatus 1 and a sheet stacking device 5 that is connected to a sheet discharge port of the image forming apparatus 1 and stacks sheets discharged from the image forming apparatus 1 are configured.

  The image forming apparatus 1 includes two paper feed cassettes 6a and 6b that can store about 100 sheets. Then, the sheet is taken out from any one of the two sheet feeding cassettes 6 a and 6 b and the sheet feeding device 4, the image data transferred from the document reading device 2 is printed on the taken sheet, and the sheet is collected by the discharge roller pair 10. Discharge to device 5.

  The image forming apparatus 1 performs electrostatic printing, and includes a beam projector 12 that forms an electrostatic latent image on a photosensitive drum 11, a developing device 13 that attaches toner ink to the electrostatic latent image, and a transfer charger 14. ing. Then, the image ink formed on the photosensitive drum 11 is transferred onto the sheet by the transfer charger 14, and the image on the sheet is heated and fixed by the fixing roller 15 disposed downstream thereof, and conveyed to the sheet stacking device 5. It is the composition to do.

  The sheet feeding device 4 includes a storage unit (storage) 30 that can store 3000 sheets more than the sheet feeding cassettes 6a and 6b, and in accordance with a sheet feeding command from the image forming apparatus 1, the sheets are imaged one by one. Supply to forming apparatus 1.

  In the document reading device 2, a first platen 16 and a second platen 17 formed of transparent glass are juxtaposed in the horizontal direction at the top of the device. The first platen 16 is used for reading a document set manually, and is formed to have a maximum size of a usable document. The second platen 17 is used for reading a document that moves at a predetermined speed.

  Inside the image reading apparatus 2, there are provided first and second reading carriages 18 and 19, and photoelectric conversion means having a condenser lens 20 and a photoelectric conversion element 21 (CCD). Although not shown, the first and second reading carriages 18 and 19 are driven by a carriage motor to reciprocate below the first platen 16 in the sub-scanning direction. The first reading carriage 18 is provided with a lamp that irradiates light toward the original and a mirror that reflects the light reflected from the original, and the second reading carriage 19 includes the first reading carriage 18. Two mirrors for guiding light from the mirror to the condenser lens 20 and the photoelectric conversion element 21 are provided. Then, the first and second reading carriages 18 and 19 move to irradiate the original set on the first platen 16 with light, and the photoelectric conversion element 21 performs photoelectric conversion on the reflected light from the original. Read. The original image data read by the photoelectric conversion element 21 is transmitted as an image signal to the beam projector 12 of the image forming apparatus 1.

  The document feeder 3 discharges the document set on the sheet feed tray 22 through the second platen 17 by the sheet transport mechanism 24 and discharges it to the sheet discharge tray 23. When reading a document passing over the second platen 17 with the document feeder 3, the first and second reading carriages 18 and 19 are stopped under the second platen 17 to read the moving document.

  FIG. 2 is a cross-sectional view showing the paper feeding device 4. FIG. 4 is a perspective view illustrating a storage 30 provided in the paper feeding device 4 of FIG. 3.

As shown in FIGS. 2 and 3, the paper feeding device 4 includes a storage 30 that is pulled out for setting sheets, and a paper feeding mechanism 31 that feeds the sheets in the storage 30. A large amount of sheets are collected in the storage 30, and a stacking tray 32 that moves up and down in the vertical direction, regulation plates 33 and 34 that regulate the position in the width direction of the sheet, and a rear end regulation plate that regulates the rear end position of the sheet. 35 and an elevating mechanism (elevating means) for elevating and lowering the stacking tray 32. The sheet feeding device 4 is provided with a sheet upper surface detection sensor 38 as a sheet upper surface detection unit that detects the position of the uppermost surface of the stacked sheets, which will be described later. The sheet upper surface detection sensor 38 may employ a detection mechanism as already known. In this embodiment, as shown in FIG. 7, a detection mechanism having a detection lever that contacts the upper surface of the envelope is employed.

  As shown in FIGS. 2 and 3, the elevating mechanism includes four wires 55 fixed to the four support portions 4 a and 4 b provided on both sides of the stacking tray 32 and four wires 55. A plurality of pulleys 52, four winding pulleys 53 that are attached to the same shaft and wind up four wires 55, a plurality of driving gears 54 for driving the four winding pulleys 53, and a driving gear And an elevating motor M 3 that drives the take-up pulley 53 via 54. Then, when the elevating motor M3 is driven to rotate in the forward direction, the four take-up pulleys 53 are rotated to wind up the wires 55, respectively. As a result, the four support portions 4a and 4b of the stacking tray 32 are pulled up simultaneously, and the stacking tray 32 is raised while maintaining a substantially horizontal state. On the other hand, when the elevating motor M3 is driven in reverse, the take-up pulley 53 is rotationally driven in the opposite direction, and the stacking tray is lowered in a horizontal state by its own weight.

  The paper feed mechanism 31 is in contact with the uppermost surface of the stacked sheets to feed out the sheets, a separation unit that separates the fed sheets into a single sheet, and feeds the sheets into one sheet by the separation unit. A conveying roller pair 43 that conveys the separated sheet to the image forming apparatus 1. The separation unit includes a paper feed roller 41 and a separation roller 42 that presses against the paper feed roller 41 and prevents the feeding of one or more sheets.

  The feeding roller 40 is provided fixed to the upper surface position (feeding position) of the sheet for feeding the sheet. In this embodiment, the feeding roller 40 is fixed at the feeding position. However, the feeding roller 40 is restricted so as not to move at least above the feeding position, and can be swung below the feeding position. You may comprise.

  FIG. 4 is an explanatory diagram showing a control system. In addition to the above-described upper surface detection sensor 38, the sheet feeding device 4 has a storage set sensor (not shown) that detects that the storage 30 is locked at a predetermined position, and the stacking tray 32 is at the lowest position. A lower limit position sensor 60 is provided for detecting the presence.

Further, the sheet feeding device 4 is provided with a stacking amount detection unit for detecting the stacking amount of sheets on the stacking tray 32. This load amount detection means is an encoder 61 which is provided on the rotating shaft of the take-up pulley 53, and which comprises a disk that rotates in synchronization with the take-up pulley 53, and a photosensor that detects the slit of the disk. By counting the output pulses of the encoder 61, the stacked amount of sheets is detected.

Reference numeral 100 in FIG. 4 denotes each motor M1, M2, based on detection signals from various sensors such as the upper surface detection sensor 38, storage set sensor, lower limit position sensor 60, encoder 61, and various information from the image forming apparatus 1. It is a control part (control means) which performs drive control of M3. This control means has a CPU, ROM, RAM, counter, etc., and performs various processes described later.

  Here, the paper feeding device 4 of the present embodiment can handle envelopes. Since the envelope has a swelling, it is difficult for the feeding roller 40 to obtain an appropriate pressure contact force for feeding the envelope. In the sheet feeding device 4 according to the present embodiment, the amount of lifting of the stacking tray 32 is controlled so that the pressure contact force between the upper surface of the envelope and the feeding roller 40 becomes an appropriate pressure contact force.

Hereinafter, the ascending operation of the stacking tray 32 when envelopes are stacked will be described with reference to the operation free chart of FIG. 5 and the state diagram of the stacking tray 32 of FIG. In the present embodiment, the operation means 101 shown in FIG. 4 can be used to select whether the storage 30, that is, the paper feeding device 4 is used for a normal sheet (plain paper) or an envelope. . In the present embodiment, the operation unit 101 is a push button switch provided in the sheet feeding device, and executes an operation for raising the stacking tray for envelopes when the push button switch is pressed. In this embodiment, the operation unit 101 is a push button switch. However, the image forming apparatus is configured such that the user selects the envelope mode with an operation panel (not shown) provided in the image forming apparatus 1. The sheet feeding device 4 may execute an envelope stacking tray raising operation according to a signal indicating the envelope mode from 1.

  In the envelope stacking tray raising operation, when an envelope is first set by the user on the stacking tray 32 of the storage 30 that has been pulled out and the storage 30 is stored in the paper feeder 4, the stacking tray 32 is moved to the lower limit position. Is detected by the lower limit sensor 60 (ST1). When it is detected (ON) that the lower limit sensor 60 is at the lower limit position, the elevating motor M3 is driven to rotate forward to raise the stacking tray 32 (ST2). The up / down motor M3 starts to count up simultaneously with the forward rotation driving (ST3). On the other hand, if the lower limit sensor 60 has not detected the stacking tray 32, an abnormality process is executed (ST20). In the abnormal process, all the operations of the sheet feeding device 4 are interrupted and the abnormality is left for the user.

  When the upper surface detection sensor 38 detects (ON) the upper surface of the envelope that is detected by the lower limit sensor 60 and is lifted by driving the lifting motor M3, the lifting motor M3 is stopped (ST4 to ST5). At this time, as shown in FIG. 6A, the upper surface of the envelope is in a state of reaching a standby position P2 that is a fixed distance away from the circumferential surface position P1 of the feeding roller 40. At the same time, the rising count is stopped (ST6). The rising count is to count the number of output pulses of the encoder 61 provided on the rotating shaft of the take-up pulley 53 for raising the stacking tray 32. By counting the number of pulses of the encoder 61, the stacking tray 32 is counted. Can be detected.

Next, if the storage 30 or the sheet feeding device 4 is set for an envelope, the previously counted rise count value, that is, until the upper surface of the envelope is detected by the upper surface detection sensor 38 from the lower limit position of the stacking tray 32. The envelope loading amount is calculated from the encoder count value (ST7 to ST8). Then, an increase value is set according to the loading amount of the envelope (ST9). In this embodiment, the increase value corresponding to the load amount is the pulse value of the encoder 61, and this pulse value is stored in advance in the ROM of the control unit 100, and the pulse value corresponding to the calculated load amount is read from the ROM. Called and set.

When the increase value is set, the elevating motor M3 is rotated forward (ST10). As a result, the stacking tray 30 is raised again, and when the set rising value (the number of pulses of the encoder 61) is reached, the lifting motor M3 is stopped. At this time, the upper surface of the envelope is in a position in contact with the peripheral surface of the feeding roller 40 fixed as shown in FIGS. The image forming apparatus 1 waits in this state until a paper feed operation instruction is issued from the image forming apparatus 1. When a paper feed operation instruction is issued, the feeding roller 40 and the paper feed roller 41 are driven to perform the paper feed operation.

Here, an increase value that is larger than the increase in the load amount is selected as each increase value according to the load amount. That is, the case where the envelope stacking height on the stacking tray 32 shown in FIGS. 6B and 6C is H1 and the case where the envelope stacking height is H2 lower than H1 will be described. When the envelope stacking height on H32 is H1 (see FIG. 6B), L2 is selected as the rising amount of the stacking tray 32, and the envelope stacking height is H2 lower than H1. (See FIG. 6B.) L3 smaller than L2 is selected as the rising amount of the stacking tray 32.

Thus, by increasing the amount of increase compared to the load amount, it is possible to increase the load on the envelope as compared to the load amount of the envelope, and to reduce variations in the pressure contact force between the envelope and the feeding roller 32. Can do.

  Next, in the above-described embodiment, the rising amount of the stacking tray 32 is changed according to the stacking amount of the envelope on the stacking tray 32. However, the detecting means detects the deformation amount when the upper surface of the envelope is pressed. 68, and when the deformation amount is equal to or less than a predetermined amount, a predetermined stacking amount may be selected regardless of the envelope stacking amount on the stacking tray 32.

  A specific configuration will be described with reference to the state diagram of FIG. 7. The detection unit 68 (compression amount detection unit), as shown in FIG. 7, presses the upper surface of the envelope, and the swing of the press lever 68 a. A swing flag 68b for detection, a photo sensor 68c for detecting the position of the swing flag 68b, and a pressing spring 68d for urging the pressing lever 68a toward the upper surface of the envelope. The detection means 68 is disposed at a position where the pressing lever 68a presses the upper surface of the envelope when the upper surface of the envelope is at the standby position P2 detected by the upper surface detection sensor 38. When the stacking tray 32 is raised and the upper surface of the envelope is detected by the upper surface detection sensor 38 and the rising of the stacking tray 32 is stopped when the upper surface of the envelope is stopped, as shown in FIG. Is not detected by the photo sensor 68c, it is determined that the amount of deformation of the envelope is not more than a predetermined amount. When the deformation of the envelope is equal to or less than a predetermined amount, a reference increase obtained by adding a slight increase amount to the increase amount corresponding to the distance from the peripheral surface position P1 to the standby position P2 of the feeding roller 40 regardless of the envelope stacking amount. Select the amount. On the other hand, when the upper surface of the envelope is detected by the upper surface detection sensor 38 and the rising of the stacking tray 32 is stopped, as shown in FIG. 7B, the swinging of the envelope pressing lever 68a causes the photosensor 68c. If it has been detected in step S1, it is determined that the amount of deformation of the envelope is larger than a predetermined amount. Then, similarly to the above-described embodiment, the rising amount is selected and set according to the loading amount, and the loading tray 32 is raised by the set rising amount. At this time, as the selected amount of increase, a value larger than the above-mentioned reference increase amount is selected, and when the envelope stacking amount is large, a larger amount of increase is selected than when the envelope is small.

  The upper surface detection sensor 38 includes a detection lever 38a that contacts the upper surface of the envelope, a detection flag 38b for detecting the swing of the detection lever 38a, a photosensor 38c that detects the position of the detection flag 38b, and a detection lever. 38a is constituted by a torsion spring 38d that biases the envelope 38 toward the upper surface of the envelope. Here, the torsion spring 38d has an urging force such that the detection lever 38a contacts the upper surface of the envelope, and the urging force is sufficiently smaller than the urging force of the pressing spring 68d of the detecting means 68. The upper surface detection sensor 38 may be configured such that the detection lever 38a is suspended by its own weight without using the torsion spring 38d and is brought into contact with the upper surface of the envelope. Of course, the upper surface detection sensor 38 may employ another configuration that does not use a detection lever.

  According to the above-described configuration, even when the load is large, if the envelope does not bulge, or if the user mistakenly loads a non-bulge sheet other than the envelope on the stacking tray, the envelope or the sheet is excessive. It is possible to prevent a heavy load from being applied.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 4 Paper feed apparatus 30 Storage 31 Paper feed mechanism 32 Stacking tray 38 Sheet upper surface detection sensor 40 Feeding roller 41 Paper feed roller 42 Separation roller 44 Bracket 60 Lower limit sensor 100 Control part M1 Paper feed motor M3 Lifting motor

Claims (5)

In a paper feeding device comprising a stacking tray for loading envelopes, a feeding roller for feeding out the envelopes loaded on the loading tray, and a paper feeding roller for feeding the fed envelopes,
A load amount detecting means for detecting the load amount of the envelope of the load tray;
A sheet feeding apparatus comprising: a changing unit configured to change a load applied to the upper surface of the envelope on the stacking tray according to the envelope stacking amount detected by the stacking amount detecting unit. Elevating means for raising and lowering the loading tray;
An upper surface detecting means for detecting that the upper surface of the envelope on the stacking tray has reached a predetermined position; and
The changing means is a setting means for setting an ascending drive amount of the elevating means from the time when the upper surface detecting means detects the upper surface of the envelope according to the envelope stacking amount detected by the detecting means; and the setting means The sheet feeding device according to claim 1, further comprising a control unit that controls driving of the elevating unit based on the ascending drive amount set in step 1.   3. The sheet feeding device according to claim 2, wherein the setting unit sets the ascending drive amount of the stacking tray larger when the stacking amount is larger than when the stacking amount is small. A compression amount detection means for detecting the compression amount of the envelopes stacked by pressing the upper surface of the envelopes stacked on the stacking tray;
The said change means has a correction means which correct | amends the raising drive amount of the said raising / lowering means set by the said setting means based on the compression amount detected by the said compression amount detection means. The sheet feeding device according to 3. The correction means is configured to increase the driving amount of the raising / lowering means from the time when the upper surface detecting means detects the upper surface of the envelope, and when the compression amount detected by the compression amount detecting means is equal to or less than a predetermined value, When the compression amount detected by the compression amount detection means is larger than a predetermined amount, the drive amount is set as the rising drive amount set by the setting means according to the envelope stacking amount detected by the detection means. The sheet feeding device according to claim 4.

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