JP2005132514A - Paper feeder and image forming device equipped with the paper feeder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device capable of preventing a recording sheet from being entangled or falling to a rear side or the like of a paper feeding cassette, at the time of drawing the paper feeding cassette or various maintenances. <P>SOLUTION: In an image forming device main body 2, the paper feeder 4 sending out the recording sheets P loaded on the uppermost portion from the paper feeding cassette 3 one by one, is provided. A peeling lever 55 forcibly peeling the recording sheets P held on a lower surface of a carrying belt 46, and a separating/air-sending portion 43 for blowing air between the recording sheet P peeled by the peeling lever 55 and the lower surface of the carrying belt 46 to separate the recording sheet P from the carrying belt 46, are provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a sheet feeding device and an image forming apparatus, and more particularly to an image forming apparatus such as a copying machine, a facsimile machine, a printer, or a multifunction machine having both functions.

  As a conventional sheet feeding device, a nail separation method, a friction pad method, a gate method, an air suction method, and the like are known. Among these, the nail separation method, the friction pad method, and the gate method all have a risk of causing paper jams and double feeding. Therefore, an air suction type paper feeding device with a low probability of occurrence of these problems has attracted attention.

  In general, this air suction type sheet feeding device includes a sheet stacking cassette for stacking a plurality of recording sheets in a stacked state, a bottom plate lift driving device for lifting and lowering the cassette bottom plate of the sheet stacking cassette, and an upper portion of the sheet stacking cassette. And a sheet conveying belt that conveys the recording sheet stacked on the uppermost part and an air suction device that adsorbs the recording sheet stacked on the uppermost part and holds it on the lower surface of the sheet conveying belt. (For example, refer to Patent Documents 1 to 3.)

JP 2000-198557 A (page 6, FIG. 1) Japanese Patent Laid-Open No. 6-9083 (page 4, FIG. 2) Japanese Patent Laid-Open No. 7-133030 (5th page, FIG. 1)

  However, in the above-described paper feeding device using air, there is a problem in that static electricity is accumulated on the sheet conveying belt when the recording sheet is continuously held and conveyed by the sheet conveying belt. When the sheet conveying belt is charged with static electricity in this way, the recording sheet positioned at the uppermost portion stacked on the sheet stacking cassette is electrostatically attracted to and stuck to the sheet conveying belt. When the sheet stacking cassette is pulled out with the recording sheet attached to the sheet conveying belt in this way, the recording sheet comes into contact with the side wall of the sheet stacking cassette, or the recording sheet falls to the back side of the sheet stacking cassette. There was also a possibility that the problem of end.

  Therefore, an object of the present invention is to return the recording sheet held by the conveying means to the sheet stacking means, for example, when the cassette is pulled out or during various maintenances, and the recording sheet falls behind the entanglement of the recording sheets or the sheet stacking means. An object of the present invention is to provide a paper feeding device that can prevent inconvenience.

  According to the first aspect of the present invention, a sheet stacking unit for stacking recording sheets, a transport unit disposed above the sheet stacking unit, and a recording sheet stacked on the sheet stacking unit are adsorbed to the transport unit. The present invention relates to a sheet feeding device including a suction unit that holds the recording sheet. The sheet feeding device according to the present invention includes a peeling lever that forcibly peels the recording sheet held by the conveying unit, and air is blown between the recording sheet separated by the peeling lever and the conveying unit. Separating air blowing means for separating the recording sheet from the conveying means is provided.

  A second aspect of the present invention relates to a paper feeding device according to the first aspect. The sheet feeding device according to the present invention is characterized in that the conveying means includes a sheet conveying belt.

  A third aspect of the present invention relates to a paper feeding device according to the first or second aspect. The sheet feeding device according to the present invention is characterized in that the sheet stacking means is a sheet feeding cassette provided with a sheet stacking plate on the bottom that can stack and lift recording sheets.

  According to a fourth aspect of the present invention, there is provided the paper feeding device according to any one of the first to third aspects. The sheet feeding device according to the present invention is characterized in that, when the separation blowing unit pulls out the sheet feeding cassette, the separation lever performs blowing after the recording sheet is separated from the conveying unit.

  A fifth aspect of the present invention relates to a paper feeding device according to any one of the first to fourth aspects. The sheet feeding device according to the present invention includes recording sheet detecting means for detecting whether or not the recording sheet is held on the conveying means, and the peeling lever is configured to be in the state where feeding is stopped. It operates based on the detection result of the detection means.

  The invention described in claim 6 relates to an image forming apparatus. An image forming apparatus according to the present invention includes the sheet feeding device according to any one of claims 1 to 5.

  According to the present invention, when the cassette is pulled out or during various maintenance, the recording sheet held by the conveying unit is returned to the sheet stacking unit, and the recording sheet is prevented from being entangled or behind the sheet stacking unit. can do.

  The best mode for carrying out the sheet feeding device and the image forming apparatus according to the present invention includes a sheet stacking unit for stacking recording sheets, a conveying unit disposed above the sheet stacking unit, and a sheet stacking unit. A suction lever that sucks the stacked recording sheets and holds the recording sheets on the transporting means, and a peeling lever that forcibly peels the recording sheets held on the transporting means, and a peeling lever that peels off the recording sheets. And separating air blowing means for blowing air between the recording sheet and the conveying means to separate the recording sheet from the conveying means.

  The conveying means described above includes a sheet conveying belt. The sheet stacking means is a paper feed cassette having a sheet stacking plate for stacking recording sheets at the bottom.

  Further, in the paper feeding device according to the present embodiment, the separating air blowing unit is set to blow air after the separation lever peels the recording sheet from the conveying unit when pulling out the paper feeding cassette.

  The paper feeding device according to this embodiment preferably includes a recording sheet detecting unit that detects whether or not the recording sheet is held by the conveying unit. The peeling lever is set to separate the recording sheet from the conveying unit when it is detected that the recording sheet is held by the conveying unit based on the detection result of the recording sheet detecting unit.

  Hereinafter, details of a sheet feeding device and an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings. However, it should be noted that the drawings are schematic and the ratio of dimensions of each member is different from the actual one. Moreover, the part from which the relationship and ratio of a mutual dimension differ also in between drawings is contained.

(Schematic configuration of image forming apparatus)
FIG. 1 is a schematic configuration diagram schematically illustrating an image forming apparatus 1 according to the present embodiment. The image forming apparatus 1 feeds sheet-by-sheet recording sheets P stacked one by one from a sheet feeding cassette 3 on which recording sheets P such as printing paper and plastic film are loaded into an image forming apparatus main body 2. An apparatus 4; a sheet conveyance unit 5 including feed rollers 5A, 5B, 5C, registration rollers 5D, and the like that conveys a recording sheet P sent out by the sheet feeding device 4 along the sheet conveyance path R; and a sheet conveyance unit 5 The image forming unit 6 that forms an image on the recording sheet P conveyed by the image forming unit 6, the fixing unit 7 that fixes the image formed on the recording sheet P by the image forming unit 6, and the recording in which the image is fixed by the fixing unit 7. A sheet discharge unit 9 that discharges the sheet P to the sheet discharge tray 8 is generally configured.

  In addition, the image forming apparatus 1 enables transmission / reception of data to / from other image forming apparatuses, computers, and the like (not shown) and controls operations of each unit such as the paper feeding device 4 and the image forming unit 6 (not shown). Department.

  The image forming unit 6 includes a drum-type photoconductor (hereinafter referred to as a photoconductor drum) 10, a charger 11 disposed around the drum-type photoconductor 10, and a position on the photoconductor drum 10 downstream of the charger 11 in the rotation direction. An exposure device 12 that irradiates the laser beam, a developing unit 13, a transfer unit 14, a static eliminator (not shown), a sheet separating unit (not shown) that separates the recording sheet P from the surface of the photosensitive drum 10, and a cleaning device 15. Are generally configured.

  The photosensitive drum 10 described above is rotationally driven in a predetermined rotational direction at a predetermined process speed (circumferential speed) by a driving unit (not shown). The surface of the photosensitive drum 10 is uniformly charged by the charger 11 with a predetermined polarity and potential.

  An electrostatic latent image is formed on the photosensitive drum 10 after charging by the exposure device 12. The exposure device 12 irradiates the charged surface of the photosensitive drum 10 with laser light that is ON / OFF controlled based on image information input from an image processing unit (not shown), and removes the charge from the laser light irradiated portion. Thus, an electrostatic latent image corresponding to the image information is formed. The electrostatic latent image formed on the surface of the photoconductive drum 10 is developed as a toner image by the developing unit 13 electrostatically adhering charged toner. As this toner, powder made of synthetic resin is generally used.

  The toner image thus formed on the surface of the photosensitive drum 10 is transferred to the recording sheet P supplied from the paper feed cassette 3. The recording sheet P stored in the paper feed cassette 3 is supplied to the transfer nip portion between the photosensitive drum 10 and the transfer portion 14 by the transport rollers 5A, 5B, and 5C and the registration roller 5D. At this time, the recording sheet P is supplied to the transfer nip portion by the registration roller 5D so as to coincide with the toner image formed on the surface of the photosensitive drum 10. As the recording sheet P supplied to the transfer nip portion is nipped and conveyed by the transfer nip portion, the toner image on the surface of the photosensitive drum 10 is electrostatically transferred to the surface by the transfer portion 14.

  After the toner image is transferred to the recording sheet P in this way, the photosensitive drum 10 is neutralized by a static eliminator. The recording sheet P to which the toner image has been transferred is separated from the photosensitive drum 10 and conveyed to the fixing unit 7. When the recording sheet P after transfer is not separated from the photosensitive drum 10, the recording sheet P is forcibly separated from the photosensitive drum 10 by the sheet separating unit and conveyed to the fixing unit 7. Further, after the toner image is transferred, the toner (residual toner) remaining on the surface without being transferred to the recording sheet P at the time of transfer is removed by the cleaning device 15 and used for the next image formation.

(Configuration of paper feeder)
The sheet feeding device 4 includes the sheet feeding cassette 3 described above, a recording sheet conveyance unit 41, a recording sheet suction unit 42 provided in the recording sheet conveyance unit 41, and a separation air blowing unit 43.

  The sheet feeding cassette 3 includes a sheet stacking plate 31 that can be moved up and down, and the height of the uppermost recording sheet P on the sheet stacking plate 31 is raised and lowered by a control unit (not shown). It is like that.

  As shown in FIGS. 1 to 3, the recording sheet conveying unit 41 includes a driving roller 44 and a driven roller 45, and a conveying belt 46 that is stretched around the driving roller 44 and the driven roller 45. As shown in FIG. 3, the drive roller 44 is driven by a motor 47. A plurality of driving rollers 44 and driven rollers 45 are arranged in a direction (width direction) perpendicular to the recording sheet feeding direction, and a plurality of pairs of driving rollers 44 and driven rollers 45 are predetermined in the roller axial direction. It is provided through an interval. Conveying belts 46 are wound around the plurality of pairs of driving rollers 44 and driven rollers 45. The transport belt 46 has a number of holes (not shown) that allow the passage of air.

  As shown in FIG. 3, the recording sheet suction unit 42 includes a suction chamber 48, an intake fan 50 attached to an intake passage 49 communicating with the suction chamber 48, and an electromagnetic as an intake port switching unit that switches the intake port. A valve 51 is provided. Among them, the suction chamber 48 is a cylindrical body having an opening (not shown) on one end side disposed in a space between the driving roller 44, the driven roller 45 and the conveyance belt 46, and the lower surface (recording) of each conveyance belt 46. An air inlet opening toward the sheet P side) is formed. An opening portion on one end side of the adsorption chamber 48 is connected to the fan chamber 52 via the intake passage 49. The fan 50 and the electromagnetic valve 51 are controlled by a control unit (not shown).

  As shown in FIG. 2, a peeling lever mounting plate 53 provided on the image forming apparatus main body 2 side is provided substantially horizontally in the lower part of the space between the driving roller 44, the driven roller 45, and the conveyance belt 46. ing. In the vicinity of the driving roller 44 on the peeling lever mounting plate 53 (downstream in the conveyance direction of the stacked recording sheets P), a peeling lever 55 supported so as to be rotated by an electromagnetic solenoid 54 is provided. The peeling lever 55 is substantially L-shaped, and a long hole for a shaft support is formed in an intermediate portion, and a support shaft provided on the peeling lever mounting plate 53 side is fitted in the long hole. By forming the elongated hole in the peeling lever 55 as described above, the peeling lever 55 can be rotated without difficulty as the electromagnetic solenoid 54 moves in and out. It should be noted that the free end of the peeling lever 55 is positioned so as to project downward from the lower surface of the lower conveyor belt 46 and to the position above the lower conveyor belt 46 as the electromagnetic solenoid 54 moves in and out. It is set to rotate between the two.

  Furthermore, in the present embodiment, is the recording sheet P adsorbed on the lower surface of the conveying belt 46 located on the lower side in the conveying direction upstream of the position where the peeling lever 55 is provided on the peeling lever mounting plate 53? An actuator 56 for detecting whether or not is provided. The actuator 56 includes a detection lever 56A that rotates in contact with the recording sheet P.

  As shown in FIG. 2, the separation blower unit 43 is a portion adjacent to the drive roller 44 on the lower surface of the conveyance belt 46 that is stretched over the drive roller 44 and the driven roller 45 (recording sheets P stacked in the paper feed cassette 3. A blower nozzle 43A that blows air toward the upstream side in the transport direction), a blower passage 43B that carries air to the blower nozzle 43A, and a blower fan 43C that blows air to the blower path 43B.

  The separation blower 43 blows air when the image forming apparatus 1 stops transferring the toner image onto the recording sheet P (when the paper feed is stopped) or when the paper feed cassette 3 is pulled out. Air is blown from the nozzle 43 </ b> A toward the conveyance belt 46.

  Prior to the start of air blowing from the air blowing nozzle 43A, when the actuator 56 detects that the recording sheet P is held on the lower surface of the conveying belt 46, the peeling lever 55 projects the operating portion of the electromagnetic solenoid 54. With the operation to be performed, it is set to rotate so as to protrude downward from the lower surface of the conveyor belt 46.

  Thus, when the peeling lever 55 protrudes from the lower surface of the conveyance belt 46, the recording sheet P held on the lower surface of the conveyance belt 46 is peeled off from the lower surface of the conveyance belt 46, and the recording sheet P and the conveyance belt are separated. A gap is formed between the lower surface of 46. By blowing air from the air blowing nozzle 43 </ b> A into this gap, the entire recording sheet P is peeled off from the lower surface of the conveyance belt 46 and returned to the paper feeding cassette 3 disposed below. The operation of holding the recording sheet P on the lower surface of the conveyance belt 46 is due to static electricity accumulated on the conveyance belt 46 when the conveyance belt 46 attracts the recording sheet P by the operation of the sheet conveyance unit 42. .

(Operation and effect of this embodiment)
Hereinafter, operations and effects of the sheet feeding device 4 according to the present embodiment and the image forming apparatus 1 including the same will be described. In this embodiment, normally, when printing or the like is performed on the recording sheet P, the recording sheet P is adsorbed to the lower surface of the conveyance belt 46 by operating the recording sheet adsorption unit 42 provided in the recording sheet conveyance unit 41. Thus, the recording sheet P can be conveyed along the sheet conveyance path R to the image forming unit 6 by the sheet conveyance unit 5.

  Further, when stopping the paper feeding or when pulling out the paper feeding cassette 3, there is a high possibility that the recording sheet P is attracted to the lower surface of the transport belt 46 due to static electricity. When it is detected that it is on the lower surface of 46, the peeling lever 55 is rotated so as to protrude from the lower surface of the conveyor belt 46, and then the air blowing operation is performed from the air blowing nozzle 43 </ b> A of the separation air blowing unit 43. ing.

  For this reason, it is possible to blow air to the gap formed between the recording sheet P peeled off from the lower surface of the conveying belt 46 by the peeling lever 55 and the lower surface of the conveying belt 46, and the entire recording sheet P is conveyed to the conveying belt 46. It can be made to peel from the lower surface. As a result, even if the paper feed cassette 3 is pulled out, the recording sheet P can be prevented from being pinched or entangled between the paper feed cassette 3 and the image forming apparatus main body 2, and recording can be performed behind the paper feed cassette 3. The inconvenience that the sheet P falls can be prevented. This has the effect of reducing the frequency of trouble processing by the maintenance manager.

(Other examples)
It should not be understood that the above description and drawings, which form part of the disclosure of the embodiments of the present invention, limit the present invention. From this disclosure, various alternative embodiments and operational techniques will be apparent to those skilled in the art.

  In the above-described embodiment, the air blowing nozzle 43A is used for peeling the recording sheet P from the lower surface of the conveying belt 46. Usually, for example, the front end of the recording sheet P stacked on the uppermost portion of the sheet stacking plate 31 is used. It is also possible to blow air on the upper side so that the recording sheet P lifted by the blown air can be easily attracted to the conveyance belt 46.

  In the above-described embodiment, the electromagnetic solenoid 54 that rotates the peeling lever 55 is set to move in and out in the horizontal direction. However, as shown in FIG. 4, the electromagnetic solenoid 54 moves in and out in the vertical direction. It may be set. In this case, as shown in FIG. 4, the intermediate portion of the peeling lever 55 is pivotally supported on the image forming apparatus main body side by the rotation support shaft 55A, and the pin 54B provided at the end of the retracting rod 54A of the electromagnetic solenoid 54 is provided. It is necessary to engage in a movable manner within a long hole 55B formed at the end of the peeling lever 55 so that the electromagnetic solenoid 54 can be moved in and out. Further, instead of the actuator 56 described above, it is a matter of course that an optical sensor 60 for detecting whether or not the recording sheet P as shown in FIG.

  Furthermore, in the above-described embodiment, the mechanism is such that the recording sheet P is peeled from the lower surface of the transport belt 46 by the rotation of the peeling lever 55, but it is of course possible to use a mechanism that simply drives the peeling lever up and down.

  The present invention can be used in the field of manufacturing an image forming apparatus such as a copying machine, a facsimile machine, a printer, or a multifunction machine having both functions.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. 1 is a schematic configuration diagram of a sheet feeding device according to an embodiment of the present invention. It is a schematic explanatory drawing of the paper feeder concerning the example of the present invention. It is a front view of the peeling lever which shows the other Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 2 ... Image forming apparatus main body, 3 ... Paper feed cassette, 4 ... Paper feed apparatus, 31 ... Sheet stacking plate, 41 ... Recording sheet conveyance part, 42 ... Recording sheet adsorption | suction , 43... Separation blower, 46... Conveying belt, 55... Release lever, 56.

Claims (6)

Sheet stacking means for stacking recording sheets, transport means disposed above the sheet stacking means, and suction means for sucking the recording sheets stacked on the sheet stacking means and holding the recording sheets on the transport means A sheet feeding device comprising:
A peeling lever for forcibly peeling the recording sheet held by the conveying means;
Separation air blowing means for blowing air between the recording sheet peeled by the peeling lever and the conveying means to separate the recording sheet from the conveying means,
A sheet feeding device comprising:   The sheet feeding device according to claim 1, wherein the conveying unit includes a sheet conveying belt.   The sheet feeding device according to claim 1, wherein the sheet stacking unit is a sheet feeding cassette including a sheet stacking plate that stacks recording sheets and can be moved up and down at a bottom portion.   4. The separation air blower according to claim 1, wherein when the paper feeding cassette is pulled out, the separation lever blows air after the release lever peels the recording sheet from the transport unit. The paper feeder described in the section.   The recording unit includes a recording sheet detecting unit that detects whether or not the recording sheet is held by the conveying unit, and the release lever operates based on a detection result of the recording sheet detecting unit in a state where feeding is stopped. The sheet feeding device according to claim 1, wherein the sheet feeding device is a sheet feeding device.   An image forming apparatus comprising the paper feeding device according to claim 1.

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