JP2008195540A - Sheet feeding device, image forming apparatus, sheet feeding method, computer program, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce an operation force necessary for inserting a paper feed tray, and to secure positional accuracy of the paper feed tray. <P>SOLUTION: As the paper feed tray 8 is in an extracted to stand by for installation, sheets are stacked in the paper feed tray, and the paper feed tray 8 is pushed in up to a prescribed position, in this invention, a retraction starting position just before a final set position, where a set detection sensor 44 is turned to turn on a solenoid 41, so that retraction action is started. Next, as the retraction action is maintained (in a lock state), an elevation motor is normally driven to rotate a drive shaft 85, and a bottom plate 81 is moved up by an eccentric rotation piece 86. When the bottom plate 81 rises till a paper surface detection sensor 89 detects the uppermost sheet surface of a sheet bundle stacked on the bottom plate 81, the elevation motor is stopped and the solenoid 41 is turned off to cancel the lock state, and start of supply paper action is waited. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sheet feeding apparatus having a sheet feeding tray that is detachably mounted on the apparatus main body, an image forming apparatus such as a copying machine, a facsimile, and a printer, and a sheet feeding apparatus provided with the sheet feeding apparatus. The present invention relates to a sheet feeding method to be executed, a computer program for executing the sheet feeding method, and a recording medium on which the computer program is recorded.

  Conventionally, a paper feed tray is slidably mounted on an image forming apparatus main body or a slide rail of the paper feed apparatus main body, and paper is replenished by pulling out the paper feed tray from the apparatus main body. Therefore, the paper supply is performed by stacking paper bundles in the pulled-out paper feed tray and feeding the paper in the apparatus body against the frictional force generated on the slide rail due to its own weight and the weight of the loaded paper. The paper feed tray is pushed into the position, and the paper feed tray is set at a predetermined position.

Also, in order to separate and pick up the sheets placed on the sheet feeding tray one by one and carry them out of the sheet feeding tray, the sheet is pressed against the sheet feeding roller provided above the sheet feeding tray with a predetermined pressure. It is necessary to apply a frictional force sufficient to pull out the paper to the paper feed roller. Therefore, in a paper feeding device in which the paper feeding tray can be pulled out from the main body, when the paper feeding tray is set at a predetermined position of the paper feeding device, the bottom plate of the paper feeding tray is pushed up so that the uppermost paper in the paper bundle is It is configured to abut on the paper feed roller with a predetermined pressure. At this time, since the drive source for pushing up the bottom plate is left on the apparatus main body side, the drive source is connected to a part of the bottom plate of the paper feed tray by coupling as shown in Patent Document 1, for example. Yes.
Japanese Patent Laid-Open No. 09-086680

  On the other hand, in recent years, the idea of barrier-free has been permeated due to consideration for the elderly and people with disabilities. In December 2000, the US federal government announced the “Accessibility Standard” in Article 508 of the Rehabilitation Act. According to this accessibility standard, it is clearly stated that "the force to operate the device and key must be 5 pounds maximum (22.2N)".

  From this point of view, considering a paper feeding device in which the paper feeding tray can be pulled out of the main body, when the paper feeding tray is set in the paper feeding device, as described above, its own weight and stacking A large operating force is required because it is performed against the frictional force generated on the slide rail due to the weight of the paper. In addition to this, a force to push in the coupling of the paper feed tray is also required immediately before the paper feed tray is attached to the paper feed device.

  In addition, a holding means that abuts against a predetermined position is also required so that the mounted paper feed tray is reliably positioned. If the holding force of the holding means is small, the paper feed tray stops at a halfway position, so the holding force must be greater than the sum of the operating force and the force for pushing the coupling. In a conventional paper feed tray, this holding force is charged by a force for inserting the paper feed tray. This charging is performed immediately before the paper feed tray is installed. Therefore, the operating force when the paper feed tray is inserted is maximized immediately before the paper feed tray is mounted, and the conventional machine requires an operating force of about 40 N.

  On the other hand, since the coupling is engaged by the rotation of the main body side drive source after the paper feed tray is mounted, the action of pushing the paper feed tray by the coupling is eliminated. Further, the drive source rotates to urge the loaded paper to the feeding means. Conversely, when pulling out the paper feed tray, a force to remove the coupling is required due to the load applied to the coupling. In recent years, since the loading capacity of the paper feed tray has increased, the bottom plate has become more robust, and the load on the coupling has increased even if the loading capacity is small. Further, since the holding means must be released, the conventional machine requires an operating force of about 30 N when pulling out the paper feed tray.

  Therefore, it is desired to reduce the operating force for the removal and attachment of the paper feed tray, and it has become unacceptable with the operating force comparable to that of conventional machines. In addition, it will be understood that in the future office environment, it will be necessary to consider the operability of the equipment assuming the use of the above-mentioned elderly and people with disabilities.

  In addition, printing on standard forms is increasing, the demand for print position accuracy is increasing, and it is strongly desired to reduce equipment downtime due to call jam.

  The present invention has been made in view of such a background, and an object thereof is to reduce an operation force when inserting a paper feed tray and not to impair the positional accuracy of the paper feed tray.

  Still another object is to prevent a call jam caused by a remaining sheet from being accidentally operated by a paper feed tray when a jam occurs.

  In order to achieve the above object, the first means feeds the paper placed on the paper feed tray, the pulling means for pulling the paper feed tray that is detachably attached to the apparatus main body to the set position. A sheet feeding apparatus having a biasing unit that biases the sheet to the side, the sheet feeding tray that has been pushed to the pulling start position immediately before the setting position is pulled by the pulling unit, and the sheet feeding tray is moved to the setting position. Control means is provided for maintaining the pulling-in operation of the pulling-in means until the biasing operation of the biasing means is finished after being pulled in.

  The second means is characterized in that, in the first means, the control means releases the pull-in operation of the pull-in means after the biasing operation of the biasing means is completed.

  The third means further comprises detection means for detecting in the second means that the sheet surface of the uppermost sheet stacked on the paper feed tray has reached a predetermined position, and the paper feed tray is provided by the detection means. When it is detected that the sheet surface of the uppermost stacked sheet has reached the predetermined position, the control means ends the urging operation.

  According to a fourth means, in the first means, the pull-in means is a solenoid, and a lever having an engaging portion that is driven by the solenoid and engages with an engaged protrusion provided on the paper feed tray side. The control means energizes the solenoid during the pulling operation to engage the engaging portion of the lever with the engaged protrusion, and pulls the paper feed tray to the set position.

  The fifth means is characterized in that, in the fourth means, the lever is swingably supported by a swing fulcrum, and the pull-in operation is performed by swinging the lever.

  According to a sixth means, in the first means, the drawing-in means is composed of an electromagnet and either the sheet feeding tray main body attracted by the electromagnet or the member to be attracted provided in the sheet feeding tray. Features.

  The seventh means is the first means wherein the pull-in means abuts the cam follower provided on the paper feed tray side and a cam follower that converts the rotational operation into a sliding movement in the rotational axis direction of the cam follower. And at least half of the cam in the axial direction is cut away from the cam follower according to the rotational position of the cam to allow sliding movement of the paper feed tray.

  The eighth means includes, in any one of the first to seventh means, a detection means for detecting a drawing start position of the paper feed tray by the drawing means, and the control means is configured to detect the paper feed by the detection means. The pull-in operation of the pull-in means is started when a tray is detected.

  The ninth means further comprises a jam detection means for detecting the occurrence of jam in any one of the first to eighth means, and the control means detects the occurrence of jam by the jam detection means, The pulling means is operated to set a state in which the sheet feeding tray cannot be pulled out.

  A tenth means is the ninth means, wherein when the jam detecting means confirms that there is no jammed sheet in the conveyance path, and the door opened during the jam processing is closed, the control means The operation of the retracting means is released.

  The eleventh means includes a sheet feeding apparatus according to any one of the first to tenth means, and an image forming means for forming an image on the sheet fed from the sheet feeding apparatus. An image forming apparatus is configured.

  The twelfth means includes a first step of drawing the paper feed tray, which is detachably attached to the apparatus main body, to the set position after the paper feed tray is positioned at the pull-in start position immediately before the paper feed tray is set; After the pulling-in operation is completed in the first step, a second step of urging the paper placed on the paper feed tray toward the feeding unit side, and the application of the urging unit in the second step A third step of maintaining the pulling operation of the pulling means until the biasing operation is completed; and after the biasing operation of the biasing means in the second step is completed, the pulling operation of the third step is performed. The sheet feeding method includes a fourth step of releasing the maintenance state.

  A thirteenth means is characterized in that, in the twelfth means, the pull-in operation of the first step is started when the paper feed tray reaches the pull-in start position.

  A fourteenth means is the twelfth means characterized in that the urging operation ends when the sheet surface of the uppermost sheet stacked on the paper feed tray reaches a predetermined position.

  The fifteenth means includes a first step of holding the paper feed tray at the set position when a jam occurs in the transport path of either the apparatus main body or the paper feed unit, and while the first step is being performed. A second step of confirming the presence or absence of a sheet on the transport path, and a third step of confirming whether or not the door of the housing is opened and closed after it is confirmed that there is no sheet in the second step; A sheet feeding method including a fourth step of releasing the holding of the set position of the paper discharge tray in the first step when it is confirmed that the door is closed in the third step. To do.

  A sixteenth means is the fifteenth means characterized in that the first step is started when the detection means detects that the sheet has stopped in the conveyance path.

  The seventeenth means is characterized in that a computer program includes a procedure for executing each step of the sheet feeding method according to any one of the twelfth to sixteenth aspects by a computer.

  The eighteenth means is characterized in that the computer program according to the seventeenth means is read by a computer and recorded on a recording medium so as to be executable.

  In the following embodiments, the paper feed tray is labeled 8, 9, 10, 11, the retracting means is the retracting apparatus 40, the biasing means is the lifting device 50, and the control means is the system control unit 30. The detecting means for detecting that the sheet surface of the uppermost sheet stacked on the tray has reached a predetermined position is the sheet surface detecting sensor 89, the solenoid is indicated by reference numeral 41, the engaged protrusion is indicated by reference numeral 87, and the engaging portion is indicated by Reference numeral 43a, lever 43, swing fulcrum fulcrum 42, electromagnet 90, suction member 91, cam follower 94, cam 93, and feeding tray start The detection means for detecting the position is the set detection sensor 44, the detection means is the jam detection sensor, the sheet feeding device is the paper feed tray 8, the paper feed units 12 to 15, and the transport roller pairs 16, 17, 18 The vertical conveying path 20, the image forming apparatus correspond to the digital multifunction peripheral 1.

  According to the present invention, since the paper feed tray is automatically pulled to the set position after being pushed to the pull start position immediately before the set position, it is possible to reduce the operation force when inserting the paper feed tray.

  Further, according to the present invention, after the paper feed tray is pulled to the set position, the pulling means is maintained until the biasing operation of the biasing means is completed. It is possible to prevent the position accuracy of the paper feed tray from being lost due to the fact that it is not displaced by the biasing operation.

  Furthermore, according to the present invention, when a jam occurs, the paper feed tray cannot be pulled out, so that it is possible to prevent a call jam from occurring due to an unintentional paper feed tray operation.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram showing an outline of the internal structure of a digital multi-function peripheral as an image forming apparatus according to an embodiment of the present invention, and FIG. 2 is a perspective view showing an appearance thereof. The digital multi-function peripheral 1 basically includes an image forming unit A, a paper feeding unit B, a fixing unit C, a document reading unit D, and an operation display unit E.

  The image forming unit A includes a photosensitive drum 2 and an image forming element provided along the outer periphery thereof. The image forming element is rotated counterclockwise in the drawing on the outer periphery of the photosensitive drum 2 (the rotating direction of the photosensitive drum). The charging unit 3, the developing unit 4, the transfer unit 5, the cleaning blade 6, and the charge eliminating lamp 26. Optical writing with a laser beam L is performed between the charging unit 3 and the developing unit 4 on the exposed surface of the photosensitive drum 2. The laser beam L is emitted to the surface of the photosensitive drum 2 from the optical scanning device 7 having a scanning optical system such as a polygon mirror and an imaging lens (not shown). Scanning is performed in the axial direction (main scanning direction).

  The charging unit 3 charges the surface of the photosensitive drum 2 to a predetermined potential, and optical writing is performed by the laser beam L to form a latent image. The latent image is developed with toner by the developing unit 4, transferred to a sheet (here, a sheet) conveyed from a sheet feeding unit B described later by a transfer unit 5 using a transfer belt, and sent to the fixing unit C side. The toner remaining on the surface of the photosensitive drum 2 is scraped off by the cleaning blade 6, and the surface of the photosensitive drum 2 is neutralized by the neutralizing lamp 27, and then rotates again toward the charging unit 3. That is, charging, optical writing, development, transfer, cleaning, and static elimination processes are performed during one rotation of the photosensitive drum 2, and this operation is repeated for each image (each image formation on a sheet).

  In this embodiment, the paper feeding section B is provided in four stages, of which the upper two stages are attached to the main body side of the digital multifunction peripheral 1 and the lower two stages are attached to the lower part of the digital multifunction peripheral main body as shown in FIG. ing. The sheet feeding unit B includes four stages of sheet feeding trays 8, 9, 10, and 11, and sheet feeding units 12, 13, 14, and 15 provided on the upper exit side of the sheet feeding trays 8 to 11 in the sheet conveying direction. The longitudinal conveyance path 20 including the conveyance roller pairs 16, 17, and 18 for guiding the sheet pulled out from each of the sheet feeding units 12 to 15 to the image forming unit A side, and the most downstream side in the sheet conveyance direction of the vertical conveyance 20 It is mainly composed of a pair of registration rollers 21 provided. As shown in the figure, the side plates 20a and 20b forming the vertical conveyance path 20 are configured to be openable around the lower hinge, and a jam has occurred on the vertical conveyance path 20 or the exit side of the paper feed units 12-15. In such a case, the side plates 20a and 20b can be opened to perform jam processing. In addition, in the external view of FIG. 2, the duplex unit F is provided in this part. Further, a registration sensor 21a is provided on the upstream side of the registration roller 21 in the sheet conveying direction so that the presence or absence of a sheet at the registration roller 21 position can be detected.

  The fixing unit C includes a fixing unit 23 that includes a heating roller 23 a and a pressure roller 23 b provided immediately downstream of the transfer unit 5 in the sheet conveyance direction. A paper discharge path 25a for discharging the paper to the paper discharge tray 26 via the paper roller 25 and a double-sided conveyance path 24a for carrying out the sheet to a double-side unit (not shown) (not shown) are provided.

  The document reading (scanner) portion D is disposed above the paper discharge tray 26, and a contact glass 28 for placing the document is provided on the upper end. Although omitted here, a unit such as an automatic document feeder (ADF) G (FIG. 3) is mounted on the upper part of the document reading unit D to perform optical scanning (scanning) of the document.

  FIG. 3 is a block diagram illustrating an outline of the control device of the digital multi-function peripheral according to the present embodiment. In the figure, the system control unit 30 controls the ADF (G), the optical scanning device 7, the image forming unit A, the fixing unit C, the paper feeding unit B, and the scanner unit D, and the operation display unit E, image memory 31, an image processing unit 32, a nonvolatile memory 33, and various sensors are connected to the system control unit 30. The system control unit 30 executes a control desired by the user in response to an instruction input from the operation display unit E, temporarily stores the image data read by the scanner unit D in the image memory 31, and then the predetermined or desired by the user Image processing is performed by the image processing unit 32 and output to the optical scanning unit 7, an image is formed by the image forming unit A, transferred to the sheet P fed from the paper feed unit B, and the paper discharge roller is transferred by the fixing unit C The paper is discharged from 27 or carried out to the duplex unit F side. These control programs are stored in the nonvolatile memory 33, and the system control unit 30 executes predetermined control according to the control program.

  In addition to the case where the control program is stored in advance in the nonvolatile memory 75 and used, for example, a CD-ROM loaded on a hard disk device (not shown) from a server or a medium driving device (not shown) via a network (not shown). The program data recorded on a recording medium such as an SD card can be downloaded and used, or the version can be upgraded.

  4 and 5 are diagrams showing the configuration and operation of the paper feed tray according to this embodiment. FIG. 4 shows a state before being set at the paper feed position, and FIG. 5 is a diagram after being set at the paper feed position. In this example, the frame for regulating the outer edge of the sheet is omitted, and the uppermost sheet feed tray 8 is taken as an example of the sheet feed tray. A pull-in device 40 having a pull-in function and a lock function for the paper feed tray 8 and an elevating device 50 for raising the bottom plate of the paper feed tray 8 are provided on the back side when viewed from the operation side OP of the paper feed unit B. ing.

  The paper feed tray 8 is provided with a bottom plate 81, a fulcrum 83 that supports the bottom plate 81 in a swingable manner, a frame (not shown) that regulates the outer edge of the sheet, and an elevating member 84, and a pull-in device 40 at the back end. An engaged protrusion 87 is provided to engage with the tip of the lever 43. The elevating member 84 includes a drive shaft 85 and an eccentric rotating piece 86, and the tip end (free end side) abuts on a position away from the fulcrum 83 on the lower surface of the bottom plate 81, and the elevating and lowering of the bottom plate 81 around the fulcrum 83. Operation is possible. Further, a paper surface detection sensor 89 is provided on the main body side of the digital multi-function peripheral 1 or the main body side of the paper feed unit B above the setting position of the paper feed tray 8, and the rotation angle of the filler 89 a extending from the paper surface detection sensor 89 is illustrated. It is detected by an optical sensor that does not detect whether the upper surface of the sheet bundle has reached the paper feeding position.

  The pull-in device 40 includes a solenoid 41, a lever 43 that is swingably supported by a fulcrum 42, and a set detection sensor 44 for the paper feed tray 8. One end of the lever 43 is connected to the actuator 41a of the solenoid 41, and the other end, which is a free end, is formed in a hook shape so that the tip part can be engaged with the engaged protrusion 87 as an engaging piece 43a. The engaging portion between the engaging piece 43a and the engaged protrusion 87 is set to have an angle of 45 ° or more with respect to the horizontal direction when engaged. This angle is determined when the solenoid 41 is turned on, the actuator 41a is pulled into the main body of the solenoid 41, and the lever 43 is rotated counterclockwise about the fulcrum 42 in FIG. 4B. Any angle may be used as long as a horizontal component force sufficient to draw the protrusion 87 by a predetermined amount is obtained.

  The set detection sensor 44 only needs to be able to detect a position at which the inclined surface of the engaging portion can come into contact so that the engaging piece 43a of the lever 43 can be engaged with and pulled into the engaging portion of the engaging protrusion 87. An installation position or an on position of the set detection sensor 44 is set so that the solenoid 41 is turned on at a position where the inclined surface of the engaging portion can contact.

  The lifting device 50 includes a lifting member 84 and a lifting drive device 51. The elevating member 84 provided below the bottom plate 81 includes a drive shaft 85, an eccentric rotating piece 86 fixed near one end of the drive shaft 85, and a radial direction of the drive shaft 85 near the other end of the drive shaft 85. And two engaging projections 87 attached in a protruding manner. When the drive shaft 85 of the elevating member 84 is rotated around its central axis, the eccentric rotary piece 86 also rotates around the central axis of the drive shaft 85, and the eccentric rotary piece 86 contacts the lower surface of the bottom plate 81. Lift up the free end of.

  The elevating drive 51 includes an elevating motor 52, a worm gear 53 attached to the output shaft of the elevating motor 52, a worm wheel 54 that meshes with the worm gear 53, a spur gear 55 that meshes with the worm wheel 54, and rotation of the spur gear 55 It consists of a coupling 56 attached to the shaft. The coupling 56 has a cylindrical shape and has four cuts extending from the free end in parallel to the rotation axis. The spring 56 is provided on the drive shaft 85 of the elevating member 84 at the cut of the coupling 56. And the drive shaft 85 of the lift member 84 is rotationally driven by the lift motor 52.

  In the paper feed tray pulling mechanism configured as described above, when the paper feed tray 8 is pulled out, a sheet bundle is stacked on the bottom plate 81 and the paper feed tray 8 is pushed into the paper feed section B, the paper feed tray 8 is It moves on the rail (not shown) to the back side of the paper feeding unit B. Then, as shown in FIG. 4A, when the attachment detection of the paper feed tray 8 is detected by the paper feed tray set detection sensor 44, the solenoid 41 is turned on and the actuator 41a is sucked. As a result, the lever 43 rotates, the inclined surface of the engaging piece 43a of the lever 43 comes into contact with the inclined surface of the engaging protrusion 87 provided on the paper feed tray 8 side, and the actuator 41a is further pulled in to the final position. When it reaches, it is locked and the energized state is maintained (FIG. 4B).

  The bottom plate is lifted when the solenoid 41 of the pull-in device 40 is operated by the set detection sensor 44 and the paper feed tray 8 is mounted, that is, the paper feed tray 8 in FIG. 4B is set at the sheet feeding position. In other words, it is started when a locked state is reached. Since the coupling 56 does not mesh with the spring pin 87 at first, the coupling 56 is pushed to the back side against the elastic biasing force of the spring 57 and rotates in a form biased to the spring pin 87. Accordingly, the paper feed tray 8 at this time receives a force that is pushed out by the coupling 56 (FIG. 4B). At this time, it is necessary to lock.

  Thereafter, when the spring pin 87 is engaged with the groove of the coupling 56 by the rotation of the coupling 56, the groove of the coupling 56 enters the spring pin 87 of the drive shaft 85 by the elastic force of the spring 57, and the driving force of the drive motor 52 is increased. It is transmitted to the drive shaft 85. On the other hand, when the engagement state (lock state) of the lever 43 with the engaged protrusion 87 is released, and then the drive motor 52 is turned on when the paper surface of the uppermost stacked paper reaches a predetermined paper feed position by the paper surface detection sensor 89. Stop (FIG. 5A). At this time, since the load due to the weight of the bottom plate / stacked paper is applied to the coupling 56 via the spring pin 87, the paper feed tray 8 can be held by this load force. The drawing-in means 2 stops the suction of the solenoid 6 when the urging operation of the urging means 4 is completed (FIG. 5B), and the lock of the paper feed tray 8 is released.

  The operation at this time is shown in the flowchart of FIG. From the state in which the paper feed tray 8 is pulled out and is waiting to be mounted, the sheets are stacked in the paper feed tray, the paper feed tray 8 is pushed in, and the set detection sensor 44 is set at a predetermined position, here just before the final set position. When turned on (step S101-Y), the solenoid 41 is turned on to start the pulling operation (step S102). Next, while the retracting operation is maintained (locked state), the elevating motor 52 is rotated forward to rotate the drive shaft 85, and the bottom plate 81 is raised by the eccentric rotating piece 86 (step S103). When the bottom plate 81 rises and the paper surface detection sensor 89 detects the uppermost sheet surface of the sheet bundle stacked on the bottom plate 81 (step S104-Y), the lifting motor 52 is stopped (step S105), and the solenoid 41 is turned on. It is turned off to release the locked state of the pull-in device 40 (step S106), and the start of the paper feeding operation is awaited.

  When pulling out the paper feed tray 8 from the main body of the digital multi-function peripheral 1, the bottom plate lowering button set by the touch panel method is pressed on the display unit 99 of the operation display unit E shown in FIG. The elevating motor 52 is reversely rotated to a position where no load force is applied, and the paper feed tray 8 is lowered. For the amount of reverse rotation, a position detection sensor may be provided separately, or the amount of forward rotation may be stored and the amount of reverse rotation may be reversed accordingly. If the paper feed tray 8 is pulled out in this state, the pulling resistance generated by the load force is eliminated, so that the operation force for pulling out can be reduced. Note that the paper feed tray can be pulled out with the same operating force as before without pressing down the bottom plate lowering button.

  In this embodiment, since the pull-in device 40 has a pull-in function and a lock function, the paper feed tray 8 cannot be pulled out during jam processing, and the paper trays 8 to 11 are pulled out carelessly during jam processing. Thus, the occurrence of a situation in which jamming is difficult is prevented by leaving the sheet torn in the sheet feeding unit B including the vertical conveyance path 20. The processing procedure at this time is shown in the flowchart of FIG.

  In this process, when at least one of a plurality of jam detection sensors provided at predetermined locations on the conveyance path is turned on (step S201-Y), the solenoid 41 is turned on from the state of FIG. 5B, and the actuator 41a is pulled in. Then, the lever 43 is operated (step S202). As a result, the engaging piece 43a of the lever 43 is engaged with the engaged protrusion 87 of the paper feed tray 8, and the state shown in FIG. 4B is reached and the paper feed tray 8 is locked at the set position.

  This state continues until the jammed sheet is taken out from the conveyance path, all the jam detection sensors are turned off (step S203), the jam processing is completed, and the operation unit side door is closed (step S204). When the door opening / closing detection sensor (not shown) detects that the door is closed, the solenoid 41 is turned off (step S205), the lock of the paper feed tray 8 is released, and the state returns to the state of FIG. Wait for the next job to start. In this state, the paper feed tray 8 is unlocked, and the paper feed tray 8 can be pulled out.

  9 and 10 are diagrams showing another embodiment of the retracting device 40. FIG. FIG. 9 shows an example in which the electromagnet 90 and the attracted portion 91 are used instead of the solenoid 41, the lever 43, and the engaged protrusion 87 in the above-described embodiment, and when the set detection sensor 44 detects the insertion of the paper feed tray 8. Then, the electromagnet 90 is energized to attract the attracted portion 91, and the paper feed tray 8 is positioned at the final setting position. While being sucked, the locked state is maintained, and when energization is released, the locked state is also released.

  FIG. 10 shows a semicircular conical cam 93 that is driven to rotate by a drive motor 92 in place of the solenoid 41, lever 43, and engaged protrusion 87 in the above-described embodiment, and a protrusion provided on the paper feed tray 8 side. In the example of the cam follower 94, when the set detection sensor 44 detects the insertion of the paper feed tray 8 (this insertion is such that the portion where the conical cam 93 is formed faces the cam follower 94), the drive motor 92 is The inclined portion on the large diameter side of the conical cam 93 first comes into contact with the edge 94a at the upper end of the cam follower 94, and the contact portion with the edge 94a of the cam follower 94 corresponds to the small diameter side according to the rotation angle. Shifting to the inclined portion, the paper feed tray 8 is pulled back. When releasing, if the cam rotates to a position where no cam is formed, the conical cam 93 does not contact the cam follower 94, so the cam follower 94 becomes free and the lock is released. In this embodiment, the pulling operation and the releasing operation are repeated every 180 ° in the rotation direction.

  Other parts that are not particularly described are configured in the same manner as in the above-described embodiment, and thus redundant description is omitted.

  In this embodiment, a digital multi-function peripheral is taken as an example of the image forming apparatus, but all devices for forming images on sheet-like members such as a digital copying machine, an analog copying machine, a printer, a facsimile, and the paper feeding device thereof are all used. Needless to say, the present invention is applicable.

  As described above, according to the present embodiment, when the paper feed tray 8 is mounted on the apparatus main body, the paper feed tray 8 is pulled into the apparatus main body from the pull-in start position by the pull-in device 40. The operating force can be reduced. Further, since the pulling force of the pulling device 40 is released after the lifting (biasing) operation of the sheet by the lifting device 50 is completed, the sheet feeding tray 8 is prevented from moving during the sheet lifting (biasing), and the sheet is lifted. (Energizing) Since the paper feed tray 8 is held by the energizing load at the time of completion, the positional accuracy of the paper feed tray 8 is not impaired.

  Further, the pull-in device 40 is operated from immediately after the occurrence of the jam until the end of the jam processing, and during that time, the paper feed tray 8 is locked so that it cannot be pulled out. It is possible to prevent the jam paper from becoming a remaining paper and a call jam due to the tray operation and increasing the downtime of the device.

1 is a diagram illustrating a schematic configuration of a digital multifunction peripheral according to an embodiment of the present invention. FIG. 2 is a perspective view illustrating a schematic configuration of the digital multifunction peripheral of FIG. 1. FIG. 2 is a block diagram illustrating a control configuration of the digital multifunction peripheral of FIG. 1. It is a figure which shows the operation | movement at the time of drawing-in of a paper feed tray, and schematic structure of a drawing-in apparatus and a raising / lowering apparatus. FIG. 5 is a diagram illustrating an operation of lifting the paper feed tray from the state of FIG. 4 and releasing the lock. It is a figure which shows schematic structure of a raising / lowering apparatus. It is a flowchart which shows the operation | movement procedure of the drawing-in operation | movement by a drawing-in apparatus, and raising / lowering operation | movement. It is a flowchart which shows the process sequence of the drawing-in apparatus in jam processing. It is a figure which shows the other Example of a drawing-in apparatus. It is a figure which shows the further another Example of a drawing-in apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Digital multifunction machine 8, 9, 10, 11 Paper feed tray 12, 13, 14, 15 Paper feed unit 16, 17, 18 Carrying roller pair 20 Vertical conveyance path 30 System control part 40 Pull-in device 41 Solenoid 42 Supporting point 43 Lever 43a Engagement part 44 Set detection sensor 50 Lifting device 87 Engagement protrusion 89 Paper surface detection sensor 90 Electromagnet 91 Adsorbed member 93 Cam 94 Cam follower B Paper feed part

Claims (18)

A sheet having pull-in means for pulling a paper feed tray that is detachably attached to the apparatus main body to a set position, and biasing means for biasing the paper placed on the paper feed tray toward the paper feed means In the feeding device,
The paper feed tray that has been pushed to the pull start position immediately before the set position is pulled by the pulling means, and after the paper feed tray has been pulled to the set position, the biasing operation of the biasing means ends. A sheet feeding apparatus comprising control means for maintaining the pulling operation of the pulling means.   The sheet feeding apparatus according to claim 1, wherein the control unit releases the pulling operation of the pulling unit after the biasing operation of the biasing unit is completed. Detecting means for detecting that the sheet surface of the uppermost sheet stacked on the sheet feeding tray has reached a predetermined position;
The control means ends the urging operation when it is detected by the detection means that the sheet surface of the uppermost sheet stacked on the paper feed tray has reached the predetermined position. Item 3. A sheet feeding apparatus according to Item 2. The pull-in means includes a solenoid and a lever that is driven by the solenoid and has an engagement portion that engages with an engagement protrusion provided on the paper feed tray side;
2. The control unit according to claim 1, wherein the control unit energizes the solenoid during a pulling operation to engage the engaging portion of the lever with the engaged protrusion, and pulls the paper feed tray to a set position. Sheet feeding device.   5. The sheet feeding apparatus according to claim 4, wherein the lever is swingably supported by a swinging fulcrum, and the pulling operation is performed by a swinging operation of the lever.   2. The sheet feeding apparatus according to claim 1, wherein the pull-in means includes an electromagnet and either the sheet feeding tray main body attracted by the electromagnet or the attracted member provided on the sheet feeding tray. .   The pull-in means includes a cam follower provided on the paper feed tray side and a cam that contacts the cam follower and converts a rotation operation into a sliding movement in the rotation axis direction of the cam follower, and is at least half of the cam axial direction. The sheet feeding device according to claim 1, wherein the sheet feeding device is notched and separated from the cam follower according to a rotational position of the cam to allow the sheet feeding tray to slide. Detecting means for detecting a drawing start position of the paper feed tray by the drawing means;
8. The sheet feeding apparatus according to claim 1, wherein the control unit starts a pull-in operation of the pull-in unit when the detection unit detects the paper feed tray. 9. It further comprises a jam detection means for detecting the occurrence of a jam,
9. The control unit according to claim 1, wherein when the jam detection unit detects the occurrence of a jam, the control unit operates the pull-in unit to set a state in which the sheet feeding tray cannot be pulled out. The sheet feeding apparatus according to claim 1.   The control means releases the operation of the pull-in means when it is confirmed by the jam detection means that there is no jammed sheet in the conveyance path, and the door opened during the jam processing is closed. The sheet feeding apparatus according to claim 9. A sheet feeding device according to any one of claims 1 to 10,
Image forming means for forming an image on a sheet fed from the sheet feeding device;
An image forming apparatus comprising: A first step of drawing the paper feed tray mounted on the apparatus main body so as to be capable of being pulled out to the set position after the paper feed tray is positioned at the pull-in start position immediately before the set position of the paper feed tray;
A second step of urging the paper placed on the paper feed tray to the feeding means side after the pulling-in operation is completed in the first step;
A third step of maintaining the pull-in operation of the pull-in means until the biasing operation of the biasing means in the second step is completed;
A fourth step of releasing the maintenance state of the pull-in operation in the third step after the biasing operation of the biasing means in the second step is completed;
A sheet feeding method characterized by comprising:   13. The sheet feeding method according to claim 12, wherein the pulling operation in the first step is started when the paper feed tray reaches a pulling start position.   13. The sheet feeding method according to claim 12, wherein the biasing operation is terminated when a sheet surface of the uppermost sheet stacked on the sheet feeding tray reaches a predetermined position. A first step of holding the paper feed tray at the set position when a jam occurs in the transport path of either the apparatus main body or the paper feed unit;
A second step of confirming the presence or absence of a sheet on the conveyance path while performing the first step;
A third step of confirming whether the door of the housing is opened or closed after it is confirmed that there is no sheet in the second step;
A fourth step of releasing the holding of the set position of the paper discharge tray in the first step when it is confirmed that the door is closed in the third step;
A sheet feeding method characterized by comprising:   The sheet feeding method according to claim 15, wherein the first step is started when the detecting unit detects that the sheet has stopped in the conveyance path.   17. A computer program comprising a procedure for executing each step of the sheet feeding method according to claim 12 by a computer.   18. A recording medium, wherein the computer program according to claim 17 is read by a computer and recorded so as to be executable.

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