JP2007161376A - Sheet feeding device and recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve highly accurate sheet feeding and carrying by preventing catching failure and feeding failure of sheets with respect to a carrying means due to shortage of carrying force. <P>SOLUTION: After sheets 9 delivered by the pickup means 1 pass through separation/feed means 2, 4, feeding by the pickup means is released once. Until the sheets 9 reach carrying means 14, 15, feeding is performed only by the separation/feed means 2, 4. After the sheets 9 reach the carrying means 14, 15, feeding by the pickup means is resumed, and after predetermined amount of the sheets 9 are fed by the pickup means and the separation/feed means 2, 4, carrying of the sheets 9 by the carrying means 14, 15 is started. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet feeding apparatus for feeding sheets such as stacked sheets and films to a conveying unit of a recording apparatus, and a recording apparatus using the sheet feeding apparatus.

  A recording apparatus having functions such as a printer, a copier, and a facsimile apparatus records an image (including characters and symbols) on a recording medium such as paper, cloth, a plastic sheet, and an OHP sheet based on image information. It is configured. There are two types of recording systems in this recording apparatus: a serial type and a line type. The serial type is a method of recording an image while alternately repeating main scanning for moving the recording head along the recording medium and paper feeding (sub scanning) of the recording medium. On the other hand, in the line type, by using a long recording head extending in the width direction of the recording medium, an image is recorded only by paper feeding (sub scanning) of the recording medium while recording one line at a time. It is a method.

  The recording apparatus is provided with a sheet feeding device for separating sheets fed as recording media stacked and stored in a cassette or the like one by one and feeding them to the image forming unit. The sheet feeding device includes a pickup unit for feeding the stacked sheets, and a separation feeding unit for separating and feeding the sheets fed by the pickup unit one by one, to the conveying unit of the recording apparatus. The sheet is supplied one by one.

  FIG. 11 is a flowchart showing an example of a feeding operation in a conventional sheet feeding apparatus. In FIG. 11, when sheet feeding is started in step S101, forward rotation of the pickup roller is started (S102), and at the same time, forward rotation of the feeding roller is also started (S103). Next, the pressure plate as the stacking means on which the sheets are stacked rises toward the pickup roller (step S104), whereby the sheet is pressed against the pickup roller and sheet feeding (sending out) is started. At the same time, the separation roller is raised and pressed against the feeding roller (step S105). When the pickup roller and the feeding roller rotate by a predetermined amount and the sheet is nipped by the nip portion between the feeding roller and the separation roller and passes through the separation roller (step S106), the pressure plate is separated from the pickup roller (step S107). .

A sheet that is separated and fed by the feeding roller and the separation roller is fed by a predetermined amount to the nip portion between the conveyance roller and the pinch roller in the recording apparatus main body where rotation is stopped. It is fed and hits the nip (step S108). The skew correction is performed by curving the leading end of the sheet by overfeeding a predetermined amount (excessively transporting) in the butted state (step S109). Next, normal rotation (rotation in the conveyance direction) of the conveyance roller is started (step S110). As a result, the sheet is nipped at the nip portion and conveyed to the image forming portion of the recording apparatus. After the conveyance of the sheet by the conveyance roller is started, the separation roller is lowered and separated from the feeding roller (step S111). Then, the rotation of the pickup roller is stopped (step S112), and at the same time, the rotation of the feeding roller is stopped (step S113). With the above operation, the sheet feeding operation for one sheet is completed (step S114).
JP 2005-324451 A

  The above-described conventional sheet feeding apparatus and recording apparatus using the same have problems to be solved as described below when the sheet is fed into the image forming unit. That is, the sheet is fed to the nip portion between the conveying roller and the pinch roller whose rotation is stopped by the pressure contact force between the feeding roller and the separation roller. The skew of the sheet is corrected by overfeeding a predetermined amount in a state where the leading end of the sheet is in contact with the nip. Thereafter, the rotation of the conveyance roller is started, the sheet is pulled in and conveyed to the image forming unit.

  Here, the pressure contact force between the feeding roller and the separation roller needs to be set to an appropriate value in order to ensure the separation performance. In other words, if the pressure contact force is too strong, double feeding of the sheet is likely to occur, and if the pressure contact force is too weak, it may cause a feeding failure such as non-feed, so this pressure contact force is an appropriate value (preferably an optimum value). Set to However, in the conventional example, the pressure contact force between the feeding roller and the separation roller is not always a value that generates a sufficient conveying force to cause the sheet to be caught in the nip portion between the conveying roller and the pinch roller. There wasn't. For this reason, for example, due to insufficient conveyance force, the sheet cannot be nipped (clamped) in the nip portion between the conveyance roller and the pinch roller, resulting in inconveniences such as sheet non-feed and conveyance failure.

  The present invention has been made in view of such technical problems. SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet feeding apparatus and a recording apparatus that can eliminate a sheet biting failure and a feeding failure due to insufficient conveying force.

  In order to achieve the above object, the present invention includes a pickup roller for sending out stacked sheets, and separation feeding means for separating and feeding the sheets sent out by the pickup roller one by one, and recording In the sheet feeding apparatus for feeding sheets one by one to the conveying means of the apparatus, after the sheet fed by the pickup roller passes through the separation feeding means, the feeding by the pickup roller is once released, Until the sheet reaches the conveying unit, the sheet is fed only by the separation feeding unit, and after the sheet reaches the conveying unit, the feeding by the pickup roller is started again, and the pickup roller and the separation feeding unit are started. After the sheet is over-fed, the conveyance of the sheet by the conveyance unit is started.

  According to the present invention, a sheet feeding device that can apply a further feeding force when feeding a sheet to the conveying unit, and can eliminate a sheet biting failure and a feeding failure due to insufficient conveyance force, and A recording device is provided.

  Embodiments of the present invention will be specifically described below with reference to the drawings. Note that the same reference numerals denote the same or corresponding parts throughout the drawings. FIG. 1 is a perspective view of a recording apparatus provided with a sheet feeding apparatus according to an embodiment of the present invention. In FIG. 1, the recording apparatus attaches a sheet feeding device 110, a conveyance unit 120, a paper discharge unit 130, an image forming unit 140, and a recovery unit 600 to a chassis 160 and the like so that they are appropriately interlocked. It is configured. The sheet feeding device 110 feeds sheets such as paper and film, which are recording media, one by one to the conveying unit 120. The conveying unit 120 guides the sheet fed from the sheet feeding apparatus to the recording position of the image forming unit and conveys the sheet through the image forming unit. The paper discharge unit 130 conveys the sheet together with the conveyance unit 120 and discharges the recorded sheet outside the apparatus main body.

  The image forming unit 140 is a part that records an image by the recording head 10 based on image information on a sheet fed by a conveying unit. In the present embodiment, the case where the recording apparatus is an ink jet recording apparatus is shown, and recording is performed by ejecting ink from a discharge port of the recording head 10 onto a sheet that is a recording medium. The recovery mechanism unit 150 is a device that maintains and recovers the ink ejection performance of the recording head 10 to a normal state. The recovery mechanism section includes recovery means such as a capping unit that covers the ejection port, a suction unit for sucking ink from the ejection port to refresh the ink in the ejection port, and a wiping unit for cleaning the ejection surface. ing. A platen 11 for guiding and supporting the sheet is provided at a position facing the recording head 10 of the image forming unit 140. An arrow A in FIG. 1 indicates the sheet conveyance direction, and an arrow B indicates the scanning direction of the recording head 10.

  FIG. 2 is a longitudinal sectional view of the image forming unit 140 and its vicinity in FIG. In FIG. 2, a transport unit 120 including a transport roller 14 and a pinch roller 15 is provided on the upstream side of the platen 11 facing the recording head 10 in the transport direction. The pinch roller is pressed against the conveyance roller by an urging means (not shown), and a conveyance force is applied to the sheet by rotating the conveyance roller while sandwiching the sheet at a nip portion formed therebetween. The recording head 10 is mounted on a carriage 20 that reciprocates along a sheet supported on the platen 11. The carriage 20 is slidably guided and supported by a guide shaft 23 and a guide rail 26.

  The image forming unit 140 records an image on a sheet by driving a recording head based on image information in synchronization with the movement of the carriage. A plurality of fine discharge ports are arranged on the discharge surface 10a of the recording head 10, and an image is recorded on the surface of the sheet by selectively discharging ink from these discharge ports based on image information. . The recorded sheet is conveyed by a paper discharge means 130 including a paper discharge roller 17 and a spur 19 that are driven in synchronization with the conveyance roller, and is discharged out of the apparatus main body. In the present embodiment, a pushing spur 18 for controlling the bending of the seat, that is, cockling, is provided by pushing the seat 9 toward the platen 11 at a predetermined position upstream of the spur 19.

  FIG. 3 is a block diagram showing a schematic configuration of control means of the recording apparatus of FIG. In FIG. 3, the control board 60 is connected to a host device 50 such as a computer via an interface 51. A central processing unit (CPU) 61 composed of a microprocessor or the like is provided on the control board 60, and this CPU 61 is connected to a ROM 62, a RAM 63, a head driver 64 and motor drivers 65, 66, 67, via a main bus 55. 68 is connected. On the other hand, the recording apparatus is provided with a detection unit 80 including detection means such as a carriage encoder sensor 81, a line feed encoder sensor 82, a paper end sensor 83, a recovery system sensor 84, and a sheet feeding sensor 85.

  The ROM 62 stores information such as programs and data stored for a long time, and the RAM 63 stores information such as writable data. Therefore, detection signals from various sensors 81 to 85 of the detection unit 80 are input from the main bus 55 to the control board 60. Then, the arithmetic processing based on the information stored in the ROM 62 and the RAM 63 is executed by the CPU 61 of the control board 60, and the operation of the corresponding mechanism unit is executed via various drivers. That is, a recording operation is performed by controlling the recording means (recording head) 10 via the head driver 64, and a sheet is conveyed by controlling the conveyance motor 69 via the motor driver 65.

  Further, the movement and stop of the carriage 20 guided and supported by the guide shaft 23 and the guide rail 26 in the main scanning direction are executed by controlling the carriage motor 70 via the motor driver 66. Further, by controlling the feeding motor 71 via the motor driver 67, the sheet feeding operation from the sheet feeding device 110 to the image forming unit 140 is performed, and the recovery motor 72 is controlled via the motor driver 68. Thus, the recovery operation of each recovery means of the recovery mechanism unit 150 is performed.

  FIG. 4 is a longitudinal sectional view showing a standby state of the sheet feeding apparatus according to the embodiment of the present invention. In FIG. 4, a plurality of sheets 9 are stacked on the stacking means including the pressure plate 3 and the stacking table 8. The sheet 9 is a recording medium such as paper or film. Pickup means including a pickup roller 1 for feeding the sheet is provided above the front portion of the stacked sheets 9. In addition, a separation feeding unit including a feeding roller 2 and a separation roller 4 that can be pressed against each other is disposed in front of the stacked sheets. The separation roller 4 is mounted on a swingable roller holder 5, and the separation roller can be pressed against or separated from the feeding roller by swinging the roller holder. Further, the conveyance roller 14 and the pinch roller 15 constituting the above-described conveyance unit 120 are located in the vicinity of the front end portion of the sheet feeding device 110.

  FIG. 5 is a flowchart showing the feeding operation of the sheet feeding device of the recording apparatus according to the embodiment of the present invention. 6 to 10 are longitudinal sectional views showing states at each stage of the feeding operation of the sheet feeding apparatus according to the present embodiment. FIG. 6 shows a state in which the pickup roller and the feeding roller start rotating, the sheet on the pressure plate is brought into contact with the pickup roller, and the separation roller is brought into contact with the feeding roller. FIG. 7 shows a state in which the sheet fed by the pickup roller is separated and fed by the feeding roller and the separation roller. FIG. 8 shows a state in which the sheet fed by the feeding roller and the separation roller is fed to the nip portion between the conveying roller and the pinch roller and is abutted against it. FIG. 9 shows a state in which the skew of the sheet is corrected by further overfeeding the feeding roller. FIG. 10 illustrates a state in which the rotation of the conveyance roller is started after the skew of the sheet is corrected and the sheet is conveyed to the image forming unit.

  Next, the feeding operation of the sheet feeding apparatus 110 according to the present embodiment will be described with reference to FIGS. FIG. 4 shows a standby state of the sheet feeding apparatus 110, and the sheet 9 as a recording medium is stacked on a stacking unit including the pressure plate 3 and the stacking table 8. FIG. 6 shows a state where the pickup of the sheet 9 is started. In FIG. 5, when feeding of the sheet 9 is started (step S1), the forward rotation (rotation in the feeding direction) of the pickup roller 1 is started (step S2), and at the same time, the forward rotation (feeding direction) of the feeding roller 2 is started. Is also started (step S3). Next, when the pressure plate 3 on which the sheets 9 are stacked rises (step S4), the sheets come into contact with the pickup roller 1 and sheet feeding is started. At the same time, the separation roller 4 rises (step S5), and the separation roller 4 comes into contact with the feeding roller 2.

  As the pickup roller 1 and the feeding roller 2 rotate, the fed sheet 9 is sandwiched between the nip portions of the feeding roller 2 and the separation roller 4 as shown in FIG. The pickup roller 1 and the feeding roller 2 are rotated by a predetermined amount, so that only one sheet is separated at the nip portion between the feeding roller and the separation roller. After the separated sheet has passed through the nip portion (step S6), the pressure plate 3 Are separated (lowered) (step S7). As shown in FIG. 8, the sheet 9 separated and conveyed is fed by the rotation of the feeding roller 2, and the nip portion of the conveying means comprising the conveying roller 14 and the pinch roller 15 that have stopped rotating. (Step S8).

  When the sheet 9 hits the nip portion of the conveying roller 14, the pressure plate 3 is raised again (step S9). Thereby, in addition to the feeding force of the feeding roller 2, a predetermined amount of feeding force by the pickup roller 1 is applied to the sheet 9. As a result, as shown in FIG. 9, overfeed for correcting the skew of the sheet is performed (step S10). At this time, in order to enable more reliable skew correction, it is preferable that the pressure plate 3 is not completely in contact with the pickup roller 1 yet. After correcting the skew by overfeeding and curving the sheet, as shown in FIG. 10, the sheet is conveyed to the image forming unit 140 by rotating the conveyance roller 14 in the normal rotation direction (step S11). The pressure plate 3 is separated from the pickup roller 1 (step S12). Simultaneously with the separation of the pressure plate, the separation roller 4 is also separated from the feeding roller 2 (step S13). Then, the rotation of the pickup roller 1 is stopped (step S14), and simultaneously, the rotation of the feeding roller 2 is also stopped (step S15), and the feeding of the sheet 9 is completed (step S16).

  According to the embodiment described above, the sheet 9 is fed to the nip portion of the conveying roller 14 and the pinch roller 15 by the pressure contact force between the feeding roller 2 and the separation roller 4, and overfeeding the sheet 9 corrects the skew of the sheet. To do. Thereafter, when the conveying roller rotates, the pressure plate 3 is brought into contact with the pickup roller 1 again to apply a feeding force to the sheet. Accordingly, a further conveying force can be applied to the sheet, and it is possible to eliminate a sheet biting failure and a conveyance failure due to insufficient conveyance force. That is, after the sheet 9 has passed the separating and feeding means 2 and 4, the feeding by the pickup means 1 is once canceled, and after the sheet reaches the conveying means 14 and 15, the feeding by the pickup means is started again. Further feeding force can be applied when the sheet 9 is fed into the conveying means. Therefore, there is provided a sheet feeding device and a recording device that can eliminate a defective biting of the sheet into the conveying means and a defective feeding due to insufficient conveyance force.

  In the above embodiment, the serial type recording apparatus that forms an image while moving the recording head mounted on the carriage with respect to the sheet has been described as an example. However, the present invention can be similarly applied to a line type recording apparatus that forms an image only by feeding a sheet using a recording head extending in the sheet width direction. In the above embodiment, the case where the recording apparatus is an ink jet recording apparatus has been described. However, the present invention is applicable to a recording apparatus using other recording methods such as a wire dot type, a thermal transfer type, a thermal type, and a laser beam type. The same applies to the case. Further, the present invention can be similarly applied regardless of the structure of the recording head, the scanning method, the number of recording heads, the arrangement state of the ejection ports on the ejection surface, the number of ink types and the properties, and the like. There is an effect.

1 is a perspective view of a recording apparatus including a sheet feeding apparatus according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view of an image forming unit and its vicinity in FIG. 1. FIG. 2 is a block diagram illustrating a schematic configuration of a control unit of the recording apparatus in FIG. 1. FIG. 4 is a longitudinal sectional view illustrating a standby state of the sheet feeding device according to the embodiment of the present invention. 6 is a flowchart illustrating a feeding operation of a sheet feeding device of a recording apparatus according to an embodiment of the present invention. FIG. 4 is a longitudinal sectional view illustrating a state in which the pickup roller and the feeding roller start rotating in the sheet feeding device according to the embodiment of the present invention, the pressure plate is pressed by the pickup roller, and the separation roller is pressed against the feeding roller. It is. FIG. 7 is a longitudinal sectional view illustrating a state in which a sheet sent out by a pickup from the state of FIG. 6 is separated and fed by a feeding roller and a separation roller. FIG. 8 is a longitudinal sectional view showing a state when a sheet fed by a feeding roller and a separation roller from the state of FIG. 7 is fed to a nip portion of a conveying roller and a pinch roller and is abutted against the sheet. FIG. 9 is a longitudinal sectional view illustrating a state in which the skew feeding of the sheet is corrected by further overfeeding the feeding roller from the state of FIG. 8. FIG. 10 is a longitudinal cross-sectional view illustrating a state in which rotation of a conveyance roller is started and a sheet is conveyed to an image forming unit after correcting the skew of the sheet in FIG. 9. 10 is a flowchart illustrating an example of a feeding operation in a conventional sheet feeding apparatus.

Explanation of symbols

1 Pickup roller (pickup means)
2 Feeding roller (separate feeding means)
3 Pressure plate 4 Separation roller (separation feeding means)
5 Roller holder 8 Loading platform 9 Sheet (recording medium)
10 recording head 11 platen 14 transport roller (transport means)
15 Pinch roller (conveying means)
17 Paper discharge roller (paper discharge means) 19 Spur (paper discharge means)
20 Carriage 23 Guide shaft 26 Guide rail 50 Host device 60 Control board 61 Central processing unit (CPU)
62 ROM
63 RAM
64 Head driver 65, 66, 67, 68 Motor driver 69 Carrying motor 70 Carriage motor 71 Feeding motor 80 Detection unit 83 Paper end sensor 85 Feeding sensor 110 Sheet feeding device 120 Conveying unit 130 Discharging unit 140 Image forming unit ( Image recording unit)
160 Chassis

Claims (5)

A pickup roller for feeding the stacked sheets; and a separation feeding unit for separating and feeding the sheets fed by the pickup roller one by one, and feeding the sheets one by one to the conveying unit of the recording apparatus In the sheet feeding device for feeding,
After the sheet sent out by the pickup roller passes through the separation feeding unit, the feeding by the pickup roller is once canceled, and the sheet is fed only by the separation feeding unit until the sheet reaches the conveying unit. The sheet feeding by the pick-up roller is started after the sheet reaches the conveying means, and the sheet feeding by the conveying means is started after the sheet is over-fed by the pick-up roller and the separation feeding means. Sheet feeding device.   2. The sheet feeding by the separation feeding unit after the sheet has arrived at the conveying unit, thereby correcting the skew of the sheet, and then starting feeding again by the pickup roller. The sheet feeding apparatus according to the description.   3. The sheet feeding apparatus according to claim 1, wherein the sheet feeding device releases the feeding by the pickup roller by separating the sheet stacked on the pressure plate from the pickup roller. 4. The sheet feeding apparatus according to claim 1, wherein the sheet feeding device is configured to start feeding again by the pickup roller by bringing the sheet stacked on the pressure plate into contact with the pickup roller. 5. A recording apparatus for recording an image on a sheet by a recording head based on image information, comprising: the sheet feeding apparatus according to claim 1.

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