JP2009113974A - Paper feeder and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feeder capable of properly coping with delay of paper feeding. <P>SOLUTION: This paper feeder comprises: a cassette for housing a plurality of papers to be fed; a paper feeding means for feeding the papers housed in the cassette; a delay detection means (S12) for detecting whether a timing for feeding the paper with the paper feeding means is lower than a predetermined timing or not; and a control means (S15) for controlling the paper feeding means so that the paper feeding timing is returned to the predetermined timing when the delay detection means detects that the paper feeding timing is lower than the predetermined timing. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a paper feeding device and an image forming apparatus, and more particularly to a paper feeding device that can cope with a delay in paper feeding and an image forming apparatus including such a paper feeding device.

  In a digital multi-function peripheral capable of forming a full color image composed of four colors of yellow, cyan, magenta, and black, an intermediate transfer member such as a transfer belt is frequently used. Specifically, first, a full-color image is formed by superimposing images formed in the respective colors on the intermediate transfer member. Then, the full-color image formed on the intermediate transfer member is transferred onto a sheet fed to the intermediate transfer member. In this way, a full color image is obtained.

  Here, the digital multi-function peripheral includes a paper feeding device that feeds paper to be transferred. The paper feeding device includes a cassette that stores paper, a rubber pickup roller (paper feeding roller) that picks up the paper in contact with the paper in the cassette, and the like. Such a pickup roller is deteriorated due to aging. In this case, for example, a slip occurs between the pickup roller and the paper, and the timing of the paper to be fed may be delayed from a predetermined timing. When such a paper feeding delay occurs, even if a full-color image is formed on the intermediate transfer member, it cannot be appropriately transferred onto the paper without matching the rotation timing of the intermediate transfer member. In such a case, the full-color image formed on the intermediate transfer member must be discarded, and toner is wasted.

Japanese Laid-Open Patent Publication No. 2003-167396 (Patent Document 1) relating to an image forming apparatus corresponding to such a delay in paper feeding is disclosed. According to Japanese Patent Application Laid-Open No. 2004-133260, it is determined that the feeding capability of the pickup roller is lowered, and when a delay in paper feeding occurs due to deterioration of the pickup roller or the like, the image forming speed is reduced accordingly. In this way, the image is transferred to the paper without discarding the full-color image.
JP 2003-167396 A

  According to Patent Document 1, an image formed can be transferred to a sheet in response to a paper feed delay. However, the image forming speed is slower than the original image forming speed of the image forming apparatus. When such a slow state of image formation lasts for a long time, the user's request may not be met.

  An object of the present invention is to provide a paper feeding device that can appropriately cope with a paper feeding delay.

  Another object of the present invention is to provide an image forming apparatus that can appropriately cope with a delay in paper feeding.

  A sheet feeding device according to the present invention includes a cassette that stores a plurality of sheets to be fed, a sheet feeding unit that feeds sheets stored in the cassette, and a sheet feeding timing by the sheet feeding unit is predetermined. If the delay detection means for detecting whether the timing is later than the timing and the delay detection means detect that the paper feeding timing is later than the predetermined timing, the paper feeding timing is returned to the predetermined timing. Control means for controlling the paper feeding means.

  Preferably, the paper feed means includes a paper feed roller that contacts the paper stored in the cassette with a predetermined pressure and picks up the paper by rotation thereof. The control means controls the pressure at which the paper feed roller and the paper come into contact to be higher than a predetermined pressure.

  More preferably, the cassette includes a bottom plate positioned at the bottom of the paper to be stored, and a lift-up motor that raises the bottom plate. The control means raises the bottom plate with a lift-up motor, reduces the distance between the stored paper and the paper feed roller, and controls the pressure between the paper feed roller and the paper to be higher than a predetermined pressure. .

  More preferably, a characteristic detecting means for detecting the characteristic of the paper is provided. The control means operates according to the characteristic of the paper detected by the characteristic detection means.

  More preferably, a period detection means for detecting the passage of a predetermined period is provided. The control means operates when the predetermined period detected by the period detection means is reached.

  In another aspect of the present invention, an image forming apparatus includes an image forming unit that forms an image and transfers the image onto a sheet, and any of the above-described sheet feeding devices. Feed paper.

  Preferably, the image forming apparatus includes an adjusting unit that adjusts a speed at which the image forming unit forms an image. When the delay detecting means detects that the paper feeding timing is later than a predetermined timing, the adjusting means makes the image forming speed slower than the predetermined speed, and when the control means is activated, the image is formed. Return the speed to the predetermined speed.

  According to the present invention, when it is detected that the paper feeding timing is later than the predetermined timing, the paper feeding timing is returned to the predetermined timing. In this case, it is possible to shorten the period in which the paper feeding delay occurs and to feed paper at the original paper feeding speed of the paper feeding device. Therefore, such a sheet feeding device and an image forming apparatus can appropriately cope with a delay in sheet feeding.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a digital multifunction peripheral 10 when an image forming apparatus including a paper feeder according to an embodiment of the present invention is applied to the digital multifunction peripheral 10. Referring to FIG. 1, a digital multifunction peripheral 10 displays a control unit 11 that controls the entire digital multifunction peripheral 10, a DRAM 12 for writing and reading image data and the like, and information that the digital multifunction peripheral 10 has. An operation unit 13 that includes a display screen and serves as an interface with the user in the digital multi-function peripheral 10, a document feeder 14 that automatically transports a document to a predetermined document reading position, and a document that has been transported by the document feeder 14 An image reading unit 15 that reads the image at a predetermined reading position, an image forming unit 16 that forms the image from a document read by the image reading unit 15 and outputs the image to a sheet, and a hard disk 17 that stores image data and the like. A FAX communication unit 18 connected to the public line 20 and a network IF (interface) for connecting to the network 21. A) unit 19, and a sheet feeding apparatus 23 for feeding a sheet to the image forming section 16. Here, the paper feeding device 23 is controlled by the control unit 11.

  The control unit 11 compresses and writes the original data supplied from the image reading unit 15 in the DRAM 12, reads the data written in the DRAM 12, decompresses and encodes the data, and outputs it by the image forming unit 16.

  The digital multi-function peripheral 10 operates as a copier by forming an image in the image forming section 16 via the DRAM 12 using the document read by the image reading section 15. Further, the digital multifunction peripheral 10 forms an image in the image forming unit 16 via the DRAM 12 using the image data transmitted from the personal computer 22 connected to the network 21 through the network IF unit 19, thereby serving as a printer. Operate. Further, the digital multifunction peripheral 10 forms an image in the image forming unit 16 through the DRAM 12 using the image data transmitted from the public line 20 through the FAX communication unit 18, and also by the image reading unit 15. The image data of the read original is transmitted to the public line 20 through the FAX communication unit 18 to operate as a facsimile machine.

  In FIG. 1, thick arrows indicate the flow of image data, and thin arrows indicate the flow of control signals or control data.

  Next, the configuration of the image forming unit 16 and the paper feeding device 23 will be described. FIG. 2 is a schematic diagram illustrating a part of the image forming unit 16 and the paper feeding device 23. In FIG. 2, the flow of paper is indicated by arrows. Referring to FIGS. 1 and 2, the image forming unit 16 is capable of forming a full color image, and includes developing devices 26a, 26b, 26c, and 26d corresponding to four colors of yellow, cyan, magenta, and black, And a transfer belt 27 as an intermediate transfer member for transferring the image of each color developed in the developing units 26a to 26d. The images of the respective colors formed by the developing units 26 a to 26 d are transferred so as to be sequentially superimposed on the transfer belt 27. In this way, a full color image is formed on the transfer belt 27 by superimposing the four color images. The full color image formed on the transfer belt 27 is transferred to the paper P fed from the cassette 24 to the transfer unit 28. The paper P to which the full color image has been transferred is discharged to the discharge tray 29 through a fixing unit (not shown).

  The sheet feeding device 23 includes a cassette 24 that stores a plurality of sheets to which images are transferred, and a sheet feeding roller 25 that feeds the sheets stored in the cassette 24 to the image forming unit 16. The paper feed roller 25 and the like operate as paper feed means. A plurality of cassettes 24 are provided according to the type of paper P. The cassette 24 includes a frame 30 that stores the paper P according to its size, and a bottom plate 31 that is positioned at the bottom of the paper P to be stored. The paper feed roller 25 is provided so as to be in contact with the uppermost paper P among the plurality of papers P stored in the frame 30. The paper feed roller 25 is composed of a rubber-like member having elasticity. The paper feed roller 25 and the paper P are in contact by being pressed with a predetermined force. The bottom plate 31 can be moved up and down by a lift-up motor (not shown), that is, in the vertical direction on the paper surface in FIG.

  Here, a case where a delay in paper feeding due to slippage of the paper feeding roller 25 occurs in the digital multi-function peripheral 10 will be described. FIG. 3 is a flowchart showing the operation of the control unit in this case. 1 to 3, first, when the control unit 11 of the digital multi-function peripheral 10 accepts a request for image formation such as copying (step S11 in FIG. 3, hereinafter, steps are omitted), the paper supply is performed. It is detected whether or not the timing of the paper is later than the predetermined timing (S12). The delay in the paper feeding timing is detected, for example, by detecting the time during which the paper P passes through various places on the transport path of the paper P, and determining whether or not this detection time is behind a predetermined time. Here, the control unit 11 operates as a delay detection unit.

  If a delay in paper feed timing is detected (YES in S12), it is determined whether or not the copy speed, that is, the image forming speed has been slowed (S13). Specifically, for example, when the digital multi-function peripheral 10 has a performance capable of forming 30 images per minute in the image forming unit 16, image formation is performed so that 29 images are formed per minute. Determine whether the speed has been reduced. If it is determined that the image forming speed has not been reduced (YES in S13), the image forming speed is reduced (S14). Here, the control unit 11 or the like operates as an adjusting unit that adjusts the image forming speed to be slow. In this way, provisional correspondence to the paper feeding delay is made.

  If it is determined that the image forming speed has been reduced, control is performed to increase the pressure at which the paper P and the paper feed roller 25 come into contact (S15). Here, an example of a method for increasing the pressure of contact between the paper P and the paper feed roller 25 will be described. FIG. 4 is a schematic diagram showing a state before increasing the pressure at which the paper P and the paper feed roller 25 come into contact with each other. FIG. 5 is a schematic view showing a state in which the contact pressure between the paper P and the paper feed roller 25 is increased.

  2, 4, and 5, paper feeder 23 includes cassette 24, paper feed roller 25, frame body 30, bottom plate 31, lift-up motor (not shown), and lift-up. Sensor 32. The bottom plate 31 can be moved by the lift-up motor in the vertical direction in FIGS. 4 and 5, that is, in the direction of the arrow A or in the opposite direction. The paper feed roller 25 is fixed at a predetermined position. Of the paper P stored in the frame 30, the uppermost paper P and the paper feed roller 25 are in contact with each other with a predetermined pressure. The paper feed roller 25 rotates in the direction indicated by the arrow B in FIGS. 4 and 5 to pick up the paper P. Further, the upper surface of the paper P is also in contact with the lift-up sensor 32. The lift-up sensor 32 includes a PI (Photo Interrupter) sensor or the like, and optically detects the amount of movement of the paper P in the vertical direction.

  If it is determined that the image forming speed has been reduced, the lift-up motor raises the bottom plate 31 in the direction in which the paper feed roller 25 is disposed, that is, in the direction indicated by the arrow A in FIG. Then, as shown in FIG. 5, the bottom plate 31 and the paper P move upward from the position indicated by the dotted line in FIG. In this way, the distance between the paper feed roller 25 and the bottom plate 31 is reduced. As a result, the paper feed roller 25 made of a rubber-like member having elasticity nips the paper P at the large area 33. In this manner, the contact pressure between the paper P stored on the bottom plate 31 and the paper feed roller 25 is increased. Then, the paper P is picked up with a force larger than a predetermined force, the slip between the paper feed roller 25 and the paper P is suppressed, and the timing for feeding the paper P is returned to the predetermined timing. In this case, the amount of upward movement of the bottom plate 31 is detected by the lift-up sensor 32, and the bottom plate 31 is raised so that the pick-up force is appropriate. Note that the amount of movement of the bottom plate 31 and the sheet P is a slight amount, and in FIG. 5, the amount of movement is exaggerated from the viewpoint of easy understanding.

  In this way, the pressure at which the paper P and the paper feed roller 25 come into contact with each other is increased, and the force for picking up the paper P is increased. That is, in the above case, the speed is set so as to form 30 images per minute. After returning the image forming speed to the original, the subsequent image is formed (S17).

  With this configuration, when it is detected that the paper feeding timing is later than the predetermined timing, the paper feeding timing is returned to the predetermined timing, and the paper feeding delay occurs. Thus, the paper can be fed at the original paper feeding speed of the paper feeding device. In this case, the paper feed delay occurs not only due to aging of the paper feeding means, but also due to the way the paper is stored, the quality of the paper, the paper size, the ambient temperature, the moisture absorption of the paper, etc. Even in this case, this can be dealt with. Therefore, such a sheet feeding device and a digital multi-function peripheral can appropriately cope with a delay in sheet feeding.

  In the above embodiment, the force for picking up the paper by raising the bottom plate, reducing the distance between the paper feed roller and the paper, and increasing the contact pressure between the paper and the paper feed roller. However, the present invention is not limited to this, and the pressure at which the paper and the feed roller contact with each other is increased by lowering the paper feed roller closer to the paper. Thus, the force for picking up the paper may be increased.

  In addition, the paper feeding device is configured to include a characteristic detecting unit that detects a characteristic of the paper, and the paper feeding unit may be controlled according to the detected paper characteristic, for example, the surface roughness of the paper. Good. That is, high-quality paper having a relatively smooth surface roughness is stored in the cassette, and when this is detected, the interval between the paper feed roller and the paper is larger than that of recycled paper having a relatively rough surface roughness. To reduce slippage of the paper feed roller.

  The sheet feeding device may include a period detection unit that detects the elapse of a predetermined period, and the control unit may be operated when the predetermined period detected thereby is reached. By doing so, the paper feeding timing can be returned to a predetermined timing at the timing requested by the user.

  In the above embodiment, the image forming speed is adjusted according to the delay of the paper feeding timing. However, the present invention is not limited to this, and if the delay of the paper feeding timing is detected, the image forming speed is adjusted. You may control to return the timing of paper feed to a predetermined timing without adjusting the speed.

  In the above-described embodiment, the control is performed so that the pressure at which the paper feed roller and the paper come into contact is increased and the paper feed timing is returned to a predetermined timing. For example, the paper feed roller may be controlled to return to a predetermined timing by increasing the rotation start timing or adjusting the rotation speed.

  In the above embodiment, the paper is picked up and fed by the paper feed roller. However, the present invention is not limited to this. It is good also as a structure provided with the paper feed means which feeds.

  In the above embodiment, the paper feeding device is included in the digital multi-function peripheral and is controlled by the control unit included in the digital multi-function peripheral. It is good also as a structure provided with the control part which controls a paper roller, a cassette, etc. and these.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

1 is a block diagram illustrating an overall configuration of a digital multi-function peripheral including a paper feeding device according to an embodiment of the present invention. FIG. 2 is a schematic diagram illustrating an image forming unit and a paper feeding device included in a digital multifunction peripheral. 6 is a flowchart illustrating an operation of a control unit when a paper feed delay occurs. It is the schematic which shows the state before making the pressure which a sheet | seat and a paper feeding roller contact high. It is the schematic which shows the state after raising the pressure which a paper and a paper supply roller contact.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Digital multifunction device, 11 Control part, 12 DRAM, 13 Operation part, 14 Document feeder, 15 Image reading part, 16 Image formation part, 17 Hard disk, 18 FAX communication part, 19 Network IF part, 20 Public line, 21 Network , 22 PC, 23 Paper feeder, 24 Cassette, 25 Paper feed roller, 26a, 26b, 26c, 26d Developer, 27 Transfer belt, 28 Transfer unit, 29 Discharge tray, 30 Frame, 31 Bottom plate, 32 Lift-up sensor 33 regions.

Claims (7)

A cassette for storing a plurality of paper to be fed;
Paper feeding means for feeding the paper stored in the cassette;
A delay detecting means for detecting whether or not a timing of feeding the paper by the paper feeding means is later than a predetermined timing;
If the delay detection means detects that the paper feeding timing is later than the predetermined timing, the control means controls the paper feeding means to return the paper feeding timing to the predetermined timing. A paper feeding device. The paper feed means includes a paper feed roller that contacts the paper stored in the cassette with a predetermined pressure and picks up the paper by rotation thereof.
The sheet feeding device according to claim 1, wherein the control unit controls the pressure at which the sheet feeding roller and the sheet are in contact with each other to be higher than the predetermined pressure. The cassette includes a bottom plate positioned at the bottom of the paper to be stored, and a lift-up motor that raises the bottom plate,
The control means raises the bottom plate by the lift-up motor, reduces the interval between the stored paper and the paper feed roller, and sets the pressure at which the paper feed roller and the paper are in contact with the predetermined level. The sheet feeding device according to claim 2, wherein the sheet feeding device is controlled to be higher than the pressure. Comprising a characteristic detecting means for detecting the characteristic of the paper;
The sheet feeding device according to claim 1, wherein the control unit operates according to the characteristic of the sheet detected by the characteristic detection unit. Comprising a period detection means for detecting the passage of a predetermined period;
The sheet feeding device according to claim 1, wherein the control unit is activated when a predetermined period detected by the period detection unit is reached. An image forming unit that forms an image and transfers the image to paper;
A sheet feeding device according to any one of claims 1 to 5,
The image forming apparatus feeds the sheet to the image forming unit. The image forming apparatus includes an adjusting unit that adjusts a speed of forming an image by the image forming unit,
If the adjusting means detects that the paper feeding timing is later than the predetermined timing by the delay detecting means, the adjusting means makes the image forming speed slower than the predetermined speed,
The image forming apparatus according to claim 6, wherein when the control unit is operated, an image forming speed is returned to the predetermined speed.

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