JP2007091363A - Sheet feeder, and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet feeder capable of matching the sheet position with the air blowing position with excellent accuracy even when deformation such as curl and waviness in a sheet surface is generated in the sheet stacking direction. <P>SOLUTION: The sheet feeder comprises a sheet storage unit for storing the sheets in a stacked state, a sheet feed unit for successively feeding the sheets stored in the sheet storage unit, an air blowing unit 19 for blowing air to the ends of the sheets stored in the sheet storage unit, a sheet height detection sensor 26 for detecting the top height of the sheets at the end of the sheet to which air is blown by the air blowing unit 19, a relative position variable means for relatively varying the air blowing position of the air blowing unit 19 and the top height position of the sheet in the stacking direction of the sheets stored in the sheet storage unit, and a control means for controlling the drive of the relative position variable means based on the result of detection of the sheet height detection sensor 26. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet feeding apparatus suitable for application to an image forming apparatus such as a copying machine, a printer, a facsimile machine, and a multifunction machine.

  In recent years, with the diversification of recording media, in addition to sheets other than plain paper, such as thick paper, OHP sheets, tracing paper, etc., whiteness and gloss have been added to the surface of the sheets in order to meet the market demand for colorization. Opportunities are increasing to form images on sheets such as coated paper and glossy paper that have been subjected to a coating process for printing. Of these, OHP sheets, tracing paper, coated paper, and glossy paper have higher sheet surface smoothness than plain paper, so that when sheets are stacked on top of one another, they adhere between the sheets. Power is greater than plain paper.

  In general, in an image forming apparatus such as a copying machine or a printer, sheets stored in a tray are separated and conveyed one by one. However, when the adhesion between the sheets stacked on the tray increases, Separation deteriorates. As a result, when feeding (feeding) sheets from the tray, misfeeds such as double feeding in which a plurality of sheets are overlapped, and sheet conveyance delay are likely to occur. In particular, in an environment with high humidity, a greater adhesion force acts between the sheets, and therefore, double feed and misfeed are likely to occur.

  Therefore, conventionally, a sheet rolling technique has been proposed in which air is blown to an end portion of a sheet accommodated in a tray to release the adhesion between the sheets by the flow of air between the sheets (for example, Patent Document 1 below). , 2). In such sheet-rolling technology, the topmost sheet (hereinafter also referred to as “top sheet”) that is stacked on top in the sheet stacking direction, and the second topmost sheet that is stacked below the top sheet. The purpose is to separate a sheet (hereinafter also referred to as “second sheet”). Therefore, in order to enhance the sheet separation effect, it is important to efficiently blow air on the uppermost layer portion of the stacked sheets. In order to realize this, it is necessary to relatively align the sheet position and the air blowing position in the sheet stacking direction. Therefore, for example, in Patent Document 2 below, a mechanism for raising and lowering the sheet feed table and the uppermost height of the sheets stacked on the tray are detected at a sheet winding position facing the sheet winding means for blowing the sheets by blowing air. A configuration including a sheet detection sensor is described.

Japanese Patent No. 2974345 JP 2000-344358 A

  However, in the conventional technique, air is blown to the front end portion of the sheet and the top height of the sheet is detected at the rear end portion of the sheet, so that the surface of the sheet stacked on the tray is In the case of deformation due to curling or undulation, there is a drawback that the position of the sheet and the position of blowing air cannot be properly aligned in the sheet stacking direction. As a specific example, as shown in FIG. 6, when the surface of the sheet P is undulating, the highest height H1 of the sheet detected by the sheet height detection sensor S and the optimum height as the air blowing position. An error Δh occurs between the position H2 and the position H2. For this reason, when the air blowing position is set in accordance with the uppermost height H1 of the sheet detected by the sheet height detection sensor S, the air is blown at a position shifted from the optimum height position H2. .

  The present invention has been made in order to solve the above-described problems. The object of the present invention is to provide a sheet position and air flow even in the sheet stacking direction even when the surface of the sheet is deformed such as curling or waving. An object of the present invention is to provide a sheet feeding apparatus capable of accurately aligning the spraying position of the sheet.

  A sheet supply apparatus according to the present invention includes a sheet storage unit that stores sheets in a stacked state, a sheet supply unit that sequentially supplies sheets stored in the sheet storage unit, and an end portion of the sheet stored in the sheet storage unit An air blowing means for blowing air onto the sheet, a sheet height detecting means for detecting the uppermost height of the sheet at the end of the sheet to which the air is blown by the air blowing means, and a stacking of the sheets accommodated in the sheet accommodating means The relative position variable means for relatively changing the air blowing position of the air blowing means and the uppermost height position of the sheet according to the direction, and the drive of the relative position variable means is controlled based on the detection result of the sheet height detecting means. And a control means.

  In the sheet supply apparatus according to the present invention, when the uppermost height of the sheet accommodated in the sheet accommodating portion is detected by the sheet height detecting means, the sheet height is detected at the end of the sheet to which air is blown by the air blowing means. Since the height detection means is configured to detect the top height of the sheet, even if the surface of the sheet is deformed such as curl or undulation, the top height of the sheet detected by the sheet height detection means An error does not occur between the air blowing position and the optimum height position as the air blowing position. Therefore, in the stacking direction of the sheets stored in the sheet storing means, the drive of the relative position varying means is controlled based on the detection result of the sheet height detecting means, and the air blowing position of the air blowing means and the uppermost position of the sheet By relatively aligning the height position, it is possible to accurately blow air to the optimum position targeted.

  According to the sheet feeding apparatus of the present invention, even if the surface of the sheet is deformed such as curling or undulation, it is optimal as the top height of the sheet detected by the sheet height detecting means and the air blowing position of the air blowing means. Since there is no error with respect to the height position, the highest position of the sheet and the air blowing position can be accurately aligned in the sheet stacking direction. For this reason, it becomes possible to efficiently separate the sheets by accurately blowing the air to a position optimal for the blowing of air.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram showing a configuration example of an image forming apparatus to which the present invention is applied. The illustrated image forming apparatus 1 includes a receiving unit 5 connected to an image reading device 2 and an external device (such as a personal computer) 3 via a communication line 4, and an image writing unit based on image data received by the receiving unit 5. 6, an image recording control unit 7 that controls 6, a drum-shaped image carrier (photosensitive drum) 8 on which an electrostatic latent image is written by the image writing unit 6, and a circumferential direction of the image carrier 8. A charging device 9, a developing device 10, and a cleaner 11, a transfer roll 12 that transfers a toner image formed on the image carrier 8 to a sheet, a fixing device 13 that fixes the toner image transferred to the sheet, A discharge roll 14 that discharges the sheet on which the toner image has been fixed by the fixing device 13, a discharge tray 15 that receives the sheet discharged by the discharge roll 14, and the opposite of the image carrier 8 and the transfer roll 12. A sheet conveying section 16 that conveys the sheet toward the position (nip position), a plurality of sheet accommodating sections 17 that accommodate sheets used for image formation in a stacked state, and a sheet accommodated in the sheet accommodating section 17 The sheet supply unit 18 is configured to include an air blowing unit 19 that blows air to the side end of the sheet stored in the sheet storage unit 17. The image reading device 2 may exist as one functional unit of the image forming apparatus 1 or may exist as a functional unit separate from the image forming apparatus 1.

  FIG. 2 is a schematic side view showing the configuration of the sheet supply apparatus provided in the image forming apparatus according to the embodiment of the present invention. The illustrated sheet supply apparatus includes a sheet storage unit 17, a sheet supply unit 18, and an air blowing unit 19. The sheet storage unit 17 is configured using a sheet storage tray having a space capable of storing a predetermined number (a plurality of) stacked sheets (sheet bundles), and the stacked sheets are placed in the space inside the tray. A bottom plate (not shown) is supported. The bottom plate (not shown) is supported so as to be lifted and lowered by a lifting mechanism (not shown). Since the sheets are supported in the sheet storage unit 17 in parallel with the main surface (upper surface) of the bottom plate (not shown), the stacking direction of the sheets is a direction orthogonal to the main surface of the bottom plate (not shown) (see FIG. 2). Vertical direction).

  The sheet supply unit 18 is disposed on the front side (the side on which the sheet is fed) of the sheet storage unit 17. The sheet supply unit 18 supplies the sheets 23 stored in the sheet storage unit 17 in order from the uppermost sheet, and includes a pickup roll 20, a feed roll 21, and a retard roll 22.

  The pickup roll 20 descends when the sheets 23 accommodated in the sheet accommodating portion 17 are sequentially supplied and comes into contact with the uppermost surface of the sheet. The sheet 23 is called from 17. The top surface of the sheet refers to the top surface of the top sheet. The feed roll 21 rotates in the direction of the arrow in the drawing to feed the sheet 23 called by the pickup roll 20 toward the sheet conveying unit 16 while niping with the retard roll 22. The retard roll 21 comes into contact with the lower surface side of the sheet 23 called between the feed roll 21 (nip position) by the pickup roll 20 and an appropriate frictional resistance force (braking force) is applied to the lower surface sheet in this contact state. Is used to prevent double feeding of sheets.

  The air blowing unit 19 is configured using a blower such as a blower or a fan, for example, and is disposed on one side of the sheet storage unit 17. The air blowing unit 19 separates the upper layer sheet 23 by blowing air from the direction perpendicular to the sheet supply direction Y to the side end of the sheet 23 accommodated in the sheet accommodating unit 17. It is the one that breaks the adhesion between them. The side end portion of the sheet refers to an end portion of the sheet that is arranged in the sheet storage portion 17 so as to face a direction orthogonal to the sheet supply direction Y. The sheet supply direction Y refers to a direction in which the sheet moves when the sheet storage unit 17 supplies the sheet by the sheet supply unit 18.

  FIG. 3 is a diagram illustrating a specific configuration example of the air blowing unit 19. The illustrated air blowing unit 19 is configured using a blower, and integrally includes an air blowing nozzle 19A. The air blowing nozzle 19 </ b> A is connected to the side wall portion of the sheet storage portion 17 in a state of being close to and facing the side end portion of the sheet 23 stored in a stacked state in the sheet storage portion 17. An air blowing port 24 is formed in the air blowing nozzle 19A. The air outlet 24 is a part that blows out air generated in the blower body toward the outside of the blower body. A sheet height detection window 25 is formed in the vicinity of the air outlet 24. The sheet height detection window 25 is provided integrally with the air blowing nozzle 19 </ b> A in a state of being side by side with the air blowing port 24.

  A seat height detection sensor 26 is incorporated in the back side of the sheet height detection window 25. The sheet height detection sensor 26 is provided integrally with the air blowing nozzle 19 </ b> A of the air blowing unit 19 in order to detect the uppermost height (height of the top sheet) of the sheet stored in the sheet storage unit 17. Is. The sheet height detection sensor 26 is configured using a reflective optical sensor having a light emitting unit 26A and a light receiving unit 26B. The height detection of the top sheet by the sheet height detection sensor 26 is performed through the sheet height detection window 25.

  In the sheet stacking direction, the position where the sheet height detection sensor 26 detects the uppermost height of the sheet (formation position of the sheet height detection window 26), and the position where the air blowing unit 19 blows air (air blowing port) 24) is set at the same height position. In the air blowing nozzle 19A, the air blowing port 24 and the sheet height detection window 25 are opened in the same direction. The direction in which the air outlet 24 blows air and the direction in which the sheet height detection sensor 26 monitors the height of the top sheet are the same. Further, in the sheet height detection sensor 26, when the light emitted from the light emitting unit 26A is reflected by the end of the sheet 23 and the return light is received by the light receiving unit 26B with a received light amount of a predetermined value or more, the sensor signal Is turned on.

  In the sheet supply apparatus having the above-described configuration, when a plurality of sheets 23 stored in a stacked state in the sheet storage unit 17 are sequentially supplied by the sheet supply unit 18, a controller (control means) (not shown) precedes the sheet storage. The bottom plate of the sheet storage unit 17 is raised by detecting the attachment of the unit 17 (for example, insertion of the sheet storage tray) with a sensor or the like and driving the lifting mechanism. As a result, the sheet 23 rises together with the bottom plate in the sheet storage portion 17. At this time, the sensor signal of the seat height detection sensor 26 is turned off when there is no sheet at the detection position of the sensor, and is turned on when it exists based on the sensor detection operation described above. Accordingly, when the bottom plate supporting the sheet 23 is raised from a sufficiently low position, the top sheet is moved to the detection position of the sheet height detection sensor 26 (26A, 26B) as shown in FIG. At that moment, the sensor signal of the seat height detection sensor 26 is switched from the off state to the on state.

  At that time, the controller starts to drive the lifting mechanism and then continuously monitors (monitors) the sensor signal of the seat height detection sensor 26. When the sensor signal is switched from the off state to the on state, Stop driving the lifting mechanism. Thereby, the uppermost height of the sheet 23 accommodated in the sheet accommodating portion 17 is positioned and arranged in a state where it matches the detection position of the sheet height detection sensor 26. Further, as shown in FIG. 4, the detection position H1 of the sheet height detection sensor 26 is set to the same height position as the air blowing position H2 of the air blowing unit 19 in the sheet stacking direction. The uppermost height position of the sheet and the air blowing position can be accurately aligned. Further, the sheet height detection sensor 26 is configured to detect the highest height of the sheet at the side end portion of the sheet 23 to which air is blown by the air blowing unit 19, so that the surface of the sheet 23 is wavy. Even if the above deformation occurs, no error occurs between the uppermost height of the sheet detected by the sheet height detection sensor 26 and the optimum height position as the air blowing position. Therefore, the air blown from the air blowing port 24 in the air blowing unit 19 can be accurately blown to the uppermost layer portion of the sheet 23 (a position optimized for the blowing of air). For this reason, air can be efficiently blown between the top sheet and the second sheet, and the sheets can be reliably separated by the flow of air between the sheets.

  Further, since the sheet height detection sensor 26 is provided integrally with the air blowing unit 19, the sheet height detection position by the sheet height detection sensor 26 and the air blowing position by the air blowing unit 19 are defined. The relative positional relationship can be ensured with high accuracy.

  Conventionally, in order to reliably blow air onto the uppermost layer portion of the sheet, a configuration in which the air blowing position is changed in the sheet stacking direction (up and down movement) using a shutter mechanism or the like has been adopted. In the apparatus configuration according to the above, since the position of the sheet and the position of blowing air can be properly and accurately aligned without being affected by the deformation (curl, undulation, etc.) of the sheet surface, Even without incorporating a mechanism (such as a shutter mechanism) that changes the air, it is possible to accurately blow air onto the target position (uppermost layer) of the sheet.

  In the above-described embodiment, the seat height detection sensor 26 is provided integrally with the air blowing unit 19. However, the present invention is not limited to this, and for example, as shown in FIG. Separately, a sheet height detection sensor 26 composed of a distance sensor or the like is disposed downward above the sheet stacking position, and the uppermost height of the sheet at the side end of the sheet 23 to which air is blown by the air blowing unit 16. The seat height detection sensor 26 may be used to detect the above.

  Further, in the sheet stacking direction, a blowing height sensor 27 for detecting a height position (for example, a height position of the air blowing nozzle 19A) where the air blowing unit 19 blows air is provided. For example, the sheet 23 accommodated in the sheet accommodating portion 17 is moved up and down so that the detected air blowing height position and the uppermost height position of the sheet detected by the sheet height detection sensor 26 are the same position. A configuration may be adopted in which the seat lifting mechanism, the nozzle lifting mechanism for lifting and lowering the air blowing nozzle 19A, or both lifting mechanisms are driven to relatively change the positions of both.

  Moreover, in the said embodiment, although demonstrated taking as an example what blows air to the side edge part of the sheet | seat 23 accommodated in the sheet | seat accommodating part 17, this invention is not limited to this, For example, although not illustrated, For blowing air to the front end of the sheet 23 stored in the sheet storage unit 17 (the end of the sheet disposed facing the downstream side in the sheet supply direction Y), or for the sheet 23 stored in the sheet storage unit 17 The invention can be similarly applied even when air is blown to the rear end portion (the end portion of the sheet disposed facing the upstream side in the sheet supply direction Y).

1 is a schematic diagram illustrating a configuration example of an image forming apparatus to which the present invention is applied. 1 is a schematic side view illustrating a configuration of a sheet supply device provided in an image forming apparatus according to an embodiment of the present invention. It is a figure which shows the specific structural example of an air spraying part. It is a figure which shows the relationship between the highest height of a sheet | seat, and the blowing position of air. It is a figure explaining the other form of this invention. It is a figure explaining the subject of a prior art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 17 ... Sheet accommodating part, 18 ... Sheet supply part, 19 ... Air blowing part, 19A ... Air blowing nozzle, 23 ... Sheet, 24 ... Air blowing port, 25 ... Sheet height detection window, 26 ... Seat height sensor

Claims (4)

Sheet storage means for storing sheets in a stacked state;
Sheet supply means for sequentially supplying the sheets stored in the sheet storage means;
Air blowing means for blowing air to the end of the sheet accommodated in the sheet accommodating means;
Sheet height detection means for detecting the highest height of the sheet at the end of the sheet to which air is blown by the air blowing means;
Relative position variable means for relatively changing the air blowing position of the air blowing means and the uppermost height position of the sheet in the stacking direction of the sheets accommodated in the sheet accommodating means;
And a control unit that controls driving of the relative position varying unit based on a detection result of the sheet height detection unit. The sheet feeding apparatus according to claim 1, wherein the sheet height unit is provided integrally with the air blowing unit. The relative position varying means comprises an elevating mechanism that elevates and lowers at least one of a sheet accommodated in the sheet accommodating means and a blowing nozzle provided in the air blowing means in the sheet stacking direction. The sheet supply apparatus according to claim 1. Sheet storage means for storing sheets in a stacked state;
Sheet supply means for sequentially supplying the sheets stored in the sheet storage means;
Air blowing means for blowing air to the end of the sheet accommodated in the sheet accommodating means;
Sheet height detection means for detecting the highest height of the sheet at the end of the sheet to which air is blown by the air blowing means;
Relative position variable means for relatively changing the air blowing position of the air blowing means and the uppermost height position of the sheet in the stacking direction of the sheets accommodated in the sheet accommodating means;
An image forming apparatus comprising: a sheet supply device including: a control unit that controls driving of the relative position varying unit based on a detection result of the sheet height detection unit.

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