JP2018008791A - Feeding device and image forming apparatus including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a feeding device capable of simply returning a sheet stagnating in a contact section between a feed roller and a separation roller in a direction opposite to a conveyance direction with an existing configuration without requiring a special component.SOLUTION: A feeding device includes: a pickup roller 13 and a feed roller 11 which convey a sheet 14; a separation roller 12 which is pushed on the roller 11 and is rotated and driven in a direction opposite to a conveyance direction; release means (not shown in figures) which separates an energization state of the roller 12 to the roller 11; and control means (not shown in figures) which controls a drive device which rotates and drives a motor for driving each roller 11, 12, and 13. The control means separates the roller 12 by the release means after the rotation driving of the roller 12 and energizing force by a spring 15 are returned in a stop state of the roller 11 after finishing a feeding operation and causes the sheet 14 stagnating in a contact section between the roller 11 and the roller 12 to return in the direction opposite to the conveyance direction. Afterwards, the energizing force is released and the roller 12 is stopped after delay for a prescribed time.SELECTED DRAWING: Figure 4

Description

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

  Conventionally, a general image forming apparatus or the like is provided with a FRR (Feed and Reverse Roller) type feeding device as a device for feeding sheets from a feeding tray. Here, the sheet is a generic name including paper, coated paper, label paper, an OHP sheet (overhead projector sheet), a film, and the like.

  In such a feeding device, the sheet is conveyed by a feed roller that conveys the sheet and is pressed against the feed roller by an urging means such as a spring to rotate the sheet in the direction opposite to the conveyance direction, and at that time, the rotational driving force A separation roller that slips around the feed roller by a torque limiter means, and when two or more sheets are fed, the separation roller returns the sheet in a direction opposite to the conveying direction. Works to rotate and separate.

  However, when there is a sheet that cannot be completely separated, the sheet may move to the downstream side in the transport direction from the contact portion (called a nip) between the feed roller and the separation roller. In general, a sensor or the like for detecting the sheet is disposed downstream of the contact portion between the feed roller and the separation roller, and when the leading edge of the sheet advances to the sensor, it is generally recognized as an obstacle. When the sheet advances to the position immediately before the sensor downstream of the contact portion between the feed roller and the separation roller, the sensor cannot recognize the state. When the feeding tray is pulled out in such a state, the sheet is caught on the conveyance path and the like, and the sheet may be damaged, which causes a trouble.

  Therefore, in order to prevent such troubles, there is already a method of returning the sheet by rotating the separation roller or returning the sheet by rotating the feed roller after rotating the feed roller after the feeding operation is completed. Proposed. As a well-known technique related to such a method, when two sheets are simultaneously fed between the feed roller and the reverse roller, the sheets other than the sheet to be fed are returned by the rotation of the reverse roller in the reverse sheet feeding direction. It is configured to prevent the sheet from being stopped when it is sandwiched between the feed roller and the reverse roller at the end of the sheet feeding operation, and to return the sheet to an appropriate position. “Image forming apparatus equipped with paper device” (see Patent Document 1) and “sheet feeding device, scanner, printer” which can sufficiently obtain conveying force for returning a plurality of multi-fed sheets to the stacking board side Facsimile and copier ”(see Patent Document 2).

  In the technique according to Patent Document 1 described above, when a sheet is sandwiched between the feed roller and the reverse roller, the connection between the feed roller and the drive source is cut off in order to return the sheet to the direction opposite to the conveyance direction. The feed roller can be rotated freely, and the sheet roller is sandwiched by the separation roller so that it can return to the direction opposite to the conveyance direction. For example, other dedicated parts such as an electromagnetic clutch are required, so that there is a problem that high costs cannot be avoided.

  Further, the technique according to Patent Document 2 similarly moves the double-fed sheet to the upstream side in the conveyance direction for the purpose of returning the double-fed sheet into the feeding tray in the direction opposite to the conveyance direction. Although it is configured to provide a pair of rollers to be conveyed, assuming that the rollers are conveyed by a downstream roller, the feed roller is often provided with a one-way clutch, and the drive system becomes complicated in order to reverse this. There is a problem that it ends up.

  The present invention has been made to solve such problems, and the technical problem thereof is that no special parts are required, and the existing configuration is easily retained in the contact portion between the feed roller and the separation roller. It is an object of the present invention to provide a feeding device capable of returning a sheet to be returned in a direction opposite to the conveyance direction and an image forming apparatus including the same.

  In order to solve the above technical problem, an embodiment of the present invention includes a feed roller that rotates and conveys a sheet in a predetermined conveyance direction, a separation roller that rotates and rotates in a direction opposite to the conveyance direction, and a separation roller. An urging unit that urges and presses the feed roller, and a torque limiter unit that slips the rotational driving force of the separation roller so that the separation roller rotates with the feed roller when the urging unit urges the feed roller. And a release means for separating the separation roller from the state where the separation roller is urged to the feed roller by the urging means, a rotation drive of the feed roller and the separation roller, and operations of the urging means, torque limiter means, and release means are controlled. And a control means for controlling the separation roller in a stopped state of the feed roller after completion of the sheet feeding operation. After the urging force by the rolling drive and urging means is restored, the separation roller is separated by the releasing means so that the sheet staying at the contact portion between the feed roller and the separation roller is returned in the direction opposite to the conveying direction. After the operation, the urging force by the urging means is released and the separation roller is stopped after being delayed for a predetermined time.

  According to the present invention, with the above configuration, no special parts are required, and the sheet staying in the contact portion between the feed roller and the separation roller can be easily returned to the direction opposite to the conveyance direction with the existing configuration. It becomes like this. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

It is the schematic which extracted the principal part structure of the feeder of the FRR system which concerns on the Example of this invention, and showed it from the side surface direction. FIG. 2 is a schematic diagram illustrating a sheet feeding operation state in a main part of the feeding device illustrated in FIG. 1 from a side surface direction. FIG. 2 is a schematic diagram illustrating a sheet feeding operation end state in a main part of the feeding device illustrated in FIG. 1 from a side surface direction. FIG. 2 is a schematic diagram illustrating a control operation state after a sheet feeding operation in a main part of the feeding apparatus illustrated in FIG. FIG. 5 is a schematic diagram illustrating a basic configuration of an image forming apparatus including a feeding device having a control operation function described with reference to FIG. 4 from a side surface direction.

  Hereinafter, the feeding device of the present invention and the image forming apparatus including the same will be described in detail with reference to the drawings.

  FIG. 1 is a schematic view showing a configuration of a main part of an FRR-type feeding apparatus according to an embodiment of the present invention, which is shown from a side surface direction.

  Referring to FIG. 1, the feeding device rotates counterclockwise to convey a sheet 14 in a predetermined conveyance direction (rightward direction in FIG. 1) and a feed roller 11 coupled thereto. And a separation roller 12 that is urged against and pressed against the feed roller 11 by a spring 15 as an urging means and rotates in a direction opposite to the conveyance direction (counterclockwise), and the separation roller 12 is fed by the spring 15. Release means (not shown) that separates the roller 11 from the state of being urged is provided as a mechanical structure portion. The biasing means that presses the separation roller 12 against the feed roller 11 may be a member or mechanism having an equivalent function other than the spring 15.

  In addition, the feeding device according to the embodiment is a computer function control means (CPU) for controlling a motor driving device that rotationally drives a DC motor, which schematically illustrates the driving of the feed roller 11, the pickup roller 13, and the separation roller 12. By the instruction control, the function as a torque limiter means for slipping the rotational driving force of the separation roller 12 so that the separation roller 12 rotates with the feed roller 11 when the separation roller 12 is urged by the spring 15 is passive. The control means (CPU) is configured to control the driving of the pickup roller 13, the feed roller 11 and the separation roller 12, and the operation of the urging means, the torque limiter means, and the releasing means.

  FIG. 2 is a schematic view showing the feeding operation state of the sheet 14 in the main part of the feeding device from the side surface direction.

  Referring to FIG. 2, here, the control means (CPU) drives and controls the pickup roller 13 against the uppermost sheet 14 from the state shown in FIG. 1 and feeds it to the contact portion between the feed roller 11 and the separation roller 12. Shows the state. At this time, when two or more sheets 14 are sent out, the sheet 14 other than the uppermost sheet is separated by the separation roller 12 and returned to the left in the direction opposite to the conveying direction in FIG. Actually, a guide shape that guides the sheet 14 to the contact portion between the feed roller 11 and the separation roller 12 at the outlet of the feeding tray on which the sheet 14 is stacked, or the sheet 14 around the feed roller 11 and the separation roller 12 is provided. Guide members for guiding are provided, both of which are schematically shown.

  FIG. 3 is a schematic view showing a state in which the feeding operation of the sheet 14 in the main part of the feeding device is completed from the side surface direction.

  Referring to FIG. 3, here, the final feeding of the sheet 14 is completed by the feeding operation, and the releasing means works by the instruction control of the control means (CPU), and the urging force to the separation roller 12 by the spring 15 is applied. Indicates the released state. By the way, if the final sheet 14 and the next sheet 14 are in a state where the adhesion force between the sheets 14 is high due to the presence of burrs, etc., as shown in FIG. A sheet may remain between the contact portions with the separation roller 12. When the feeding tray is pulled out in such a state, the uppermost sheet 14 may collide with a peripheral guide member or the like and damage the leading end portion or the peripheral portion. Therefore, in the present invention, the control means (CPU) returns the sheet 14 conveyed beyond the contact portion between the feed roller 11 and the separation roller 12 after the feeding operation is completed in the direction opposite to the conveying direction, and the feeding tray. It is a technical purpose to have a control operation function that can be returned to the inside.

  In order to achieve such an object, the control means (CPU) returns the urging force by the spring 15 of the urging means and the rotation drive of the separation roller 12 while the feed roller 11 and the pickup roller 13 are stopped after the feeding operation is finished. After the separating roller 12 is separated by the releasing means and the sheet 14 staying at the contact portion between the feed roller 11 and the separating roller 12 is made to return in the direction opposite to the conveying direction, the urging force of the spring 15 is released. The separation roller 12 is stopped after a predetermined delay. When such a control operation function is provided with detection means (sensor) for detecting the rotation drive of the separation roller 12 and the rotation drive of the feed roller 11 accompanying the return of the urging force by the spring 15 on the downstream side in the transport direction, the control means (CPU ) Preferably stops the separation roller 12 when the rotation of the feed roller 11 is detected by the detection means (sensor). Incidentally, the control means (CPU) can change and set a predetermined time for which the separation roller 12 is stopped after being delayed, and can set a predetermined time delay in a plurality of patterns according to the size and type of the sheet 14, for example. Is. When the sheet detecting means (sensor) for detecting the sheet 14 is provided on the downstream side in the conveying direction at the contact portion between the feed roller 11 and the separation roller 12, the control means (CPU) is the sheet detecting means (sensor). It is preferable that the separation roller 12 is stopped after a predetermined time delay if it is detected, and the separation roller 12 is stopped without delay unless the sheet detection means (sensor) detects the sheet 14.

  FIG. 4 is a schematic view showing the control operation state after the feeding operation of the sheet 14 in the main part of the feeding device described above is seen from the side surface direction.

  Referring to FIG. 4, here, after the feeding operation is finished, the control means (CPU) releases the rotational drive of the separation roller 12 and the urging force of the spring 15 after the feed roller 11 and the pickup roller 13 are stopped. The state immediately before the separation roller 12 is separated from the feed roller 11 by separating the separation roller 12 by means is shown. Immediately before the separating roller 12 that is being rotated is separated from the feed roller 11, the sheet 14 staying at the contact portion between the feed roller 11 and the separating roller 12 is returned to the direction opposite to the conveying direction. Since the conveying force is generated by the counterclockwise rotation indicated by the arrow, when the sheet 14 remains at the contact portion between the feed roller 11 and the separation roller 12, the sheet 14 is returned to the feeding tray indicated by the arrow. . Further, the control means (CPU) then performs a control operation to stop the separation roller 12 after releasing the biasing force of the spring 15 and delaying it for a predetermined time.

  In short, in the feeding device according to the embodiment, after the final feeding operation of the sheet 14 is finished, the control unit (CPU) stops the rotation driving of the feed roller 11, the pickup roller 13, and the separation roller 12, and the separation roller 12. The urging force of the spring 15 for urging the feed roller 11 is released. However, these operations are continued, and once the rotational driving of the separation roller 12 and the urging force of the spring 15 are restored, the releasing means releases the separation roller 12. After the separation, the driving of the separation roller 12 is stopped after a predetermined time. The stopping of the rotational driving of the feed roller 11 and the pickup roller 13 and the rotational driving of the separation roller 12 and the return of the urging force by the spring 15 may be performed simultaneously. According to such a control operation function, when the separation roller 12 is separated from the feed roller 11 again, the separation roller 12 is separated while rotating in a direction to return the sheet 14 in the direction opposite to the conveyance direction. Immediately before the separation roller 12 moves away from the feed roller 11, there is a moment when the urging force of the separation roller 12 remains slightly (contacts lightly). During this period, the sheet 14 is driven by the rotation of the separation roller 12. Is generated in a direction opposite to the original conveying direction (a state opposite to the separation pad type feeding). With this instantaneous conveying force, the sheet 14 can be conveyed in the direction opposite to the original conveying direction and returned to the feeding tray.

  FIG. 5 is a side view illustrating a schematic configuration of the image forming apparatus 100 including the feeding device having the control operation function described with reference to FIG.

  Referring to FIG. 5, an image forming apparatus 100 here is a digital multifunction peripheral (MFP) specification in which a plurality of functions such as a printer, a copier, a scanner, and a facsimile are combined in a single casing. Yes, the scanner unit 101 and the laser recording unit 102 perform image processing and processing such as printing on the sheet 14, and perform post-processing by aligning the sheets 14 to be carried out to the tray 103. The motor driving device controlled by the means (CPU) drives the feed roller 11, the pickup roller 13 and the separation roller 12 provided in the sheet conveying unit 107 corresponding to the feeding device according to the embodiment of the laser recording unit 102. Inside a DC motor or electrophotographic process unit (image forming unit) 109 Color printing provided applied to (black k, magenta m, cyan c, yellow y) drum drive motor for rotating the drum 119 is a photoreceptor for.

  Since the basic configuration and processing functions of the image forming apparatus 100 shown in FIG. 5 are well known, they will be briefly described. The scanner unit 101 includes an automatic double-sided document feeder (RADF) 105 that feeds a document to the upper surface of a transparent glass platen 104 and a document placed on the upper surface of the document platen 104. And a scanner unit 106 for reading the image. Image data read by the scanner unit 101 is output to the laser recording unit 102. The automatic double-sided document feeder 105 is a single-sided document feed path from the document tray shown schematically to the discharge tray similarly shown via the document table 104, and the front and back sides of the document on which one-sided image reading by the scanner unit 106 has been completed. It has a double-sided document feed path that reverses and guides it back to the document table, and can handle both single-sided and double-sided originals.

  The scanner unit 106 irradiates a document with light generated by a semiconductor laser, and forms an image of reflected light of the document on a light receiving surface of a photoelectric conversion element with a lens, a mirror, or the like. The photoelectric conversion element converts the reflected light on the image surface of the document into an electrical signal and outputs it to an image processing board corresponding to the control means (CPU) described above. The laser recording unit 102 is provided with a feed roller 11, a separation roller 12, and a pickup roller 13 (illustrated only in the vicinity of the lowermost feed tray) in the vicinity of the feed tray in which the sheets 14 are stacked and accommodated. A sheet conveying unit 107 that conveys the sheet 14, a laser writing unit 108, and an electrophotographic process unit 109. The sheet transport unit 107 includes a sub-transport path that reverses the front and back surfaces of the sheet 14 that has passed through the fixing roller and guides it to the electrophotographic process unit 109 again in the double-sided copying mode in which images are formed on both surfaces of the sheet 14. ing. The laser writing unit 108 includes a semiconductor laser that irradiates a laser beam L based on image data supplied from an image processing board, and the laser beam L emitted from the semiconductor laser passes through a mirror or a lens to an electrophotographic process unit 109. The light is distributed on the surface of the drum 119. An electrostatic latent image is formed on the surface of the drum 119, and is visualized as a toner image by supplying toner from the developing device. The toner image is transferred from the feeding tray of the sheet conveying unit 107 and transferred onto the guided sheet 14, and then heated and pressurized by a fixing roller, so that the toner image is melted and fixed on the surface of the sheet 14. To do. In this way, after the writing of the image data on the sheet 14 is completed, a part of the unloading sheet 14 is aligned and discharged to the tray 103 for post-processing.

  However, the image forming apparatus illustrated in FIG. 5 is merely an example, and a feeding apparatus having a control operation function according to the embodiment is, for example, a scanner unit 101 that is not an automatic duplex document feeder (RADF) 105 but an automatic document feeder. The present invention can be applied to various types of image forming apparatuses, such as an apparatus (ADF: Automatic Document Feeder).

DESCRIPTION OF SYMBOLS 11 Feed roller 12 Separation roller 13 Pickup roller 14 Sheet 15 Spring 100 Image forming apparatus 101 Scanner part 102 Laser recording part 103 Tray 104 Document stand 105 Automatic double-sided document feeder (RADF)
106 Scanner unit 107 Sheet conveying unit 108 Laser writing unit 109 Electrophotographic process unit (image forming unit)
119 drums

Japanese Patent No. 4293965 Japanese Patent No. 5587461

Claims (6)

A feed roller that rotates and conveys the sheet in a predetermined conveyance direction; a separation roller that rotates and rotates in a direction opposite to the conveyance direction; and an urging unit that urges and presses the separation roller against the feed roller; Torque limiter means for slipping a rotational driving force of the separation roller so that the separation roller rotates with the feed roller when the separation roller is urged to the feed roller by the urging means; and the separation roller by the urging means A release means for separating the feed roller from the state of being urged by the feed roller, a rotation drive for the feed roller and the separation roller, and a control means for controlling the operation of the urge means, the torque limiter means, and the release means. In a feeding device comprising:
The control means returns the driving force of the separating roller and the urging force by the urging means after the feeding operation of the sheet is stopped after the sheet feeding operation is finished, and then separates the separating roller by the releasing means. After the sheet staying at the contact portion between the feed roller and the separation roller is moved back in the direction opposite to the conveyance direction, the biasing force by the biasing means is released and the sheet is delayed for a predetermined time, and then A feeding device characterized in that the separation roller is stopped. The feeding device according to claim 1,
Detecting means for detecting the rotational drive of the separation roller and the rotational drive of the feed roller accompanying the return of the urging force by the urging means on the downstream side in the transport direction;
The feeding device according to claim 1, wherein the control unit stops the separation roller when the detection unit detects rotational driving of the feed roller. The feeding device according to claim 1 or 2,
The feeding device according to claim 1, wherein the control means can change and set the predetermined time during which the separation roller stops with a delay. In the feeding device according to any one of claims 1 to 3,
Sheet detecting means for detecting the sheet on the downstream side in the transport direction at the contact portion between the feed roller and the separation roller;
The control means stops the separation roller after the predetermined time delay if the sheet detection means detects the sheet, and delays the separation roller without delay if the sheet detection means does not detect the sheet. A feeding device characterized by stopping the operation. The feeding device according to claim 3,
The feeding device according to claim 1, wherein the control unit can set the delay of the predetermined time in a plurality of patterns according to the size and type of the sheet.   An image forming apparatus comprising the feeding device according to claim 1.