JP2014169154A - Paper feeder and image forming apparatus - Google Patents

Abstract

The present invention provides a paper feeding device capable of adjusting not only the air volume but also the wind pressure and capable of dealing with many types of paper. SOLUTION: Air is discharged to at least one of the side surface and the front surface of a stacked paper bundle. The blower 40, which is a paper feeding device 10 including the blower 40 that floats the paper, connects an air suction port 47 that takes in the air to be discharged and an air outlet 48 that blows out the air, and an air passage 45 through which air flows, An upstream fan 41, a downstream fan 42, a bypass channel 46 that allows air from downstream that does not pass through the downstream fan 42, and the air channel 45 to be arranged in the channel 45 in a direction along the air flow direction. And an opening / closing door 43 that adjusts the amount of air flowing through the bypass passage 46, and an opening / closing door driving means 49 that drives the opening / closing door.
[Selection] Figure 3

Description

  The present invention relates to a sheet feeding device that includes a blowing unit that sends air for sheet floating to a stack of stacked sheets, and conveys the uppermost sheet, and an image forming apparatus including the sheet feeding device.

  2. Description of the Related Art Conventionally, in image forming apparatuses such as copying machines and printers, a sheet feeding unit that feeds sheets one by one to the transfer position in order to transfer a toner image formed on a photoreceptor onto the sheet at a transfer position. A device is provided.

  As this paper feeding device, in Patent Document 1, air is blown by a fan from one end side in the conveyance direction of the paper loaded on the tray to float the paper, and the floated paper is sucked to the conveyance belt and conveyed. The structure to perform is disclosed.

  Here, since the flying height of the paper varies depending on the paper type and the paper thickness, the lifting and lowering of the paper tray on which the paper is stacked is positioned so that the floating position of the paper that has been lifted by blowing air is within a predetermined range. To control.

  For example, in Patent Document 2, it is determined by a position detection means whether the floating position of the floated paper is within a predetermined range, and when it is out of the predetermined range, the paper base is raised and lowered, There is a description that controls so that the floated paper is positioned within a predetermined range.

  Further, Patent Document 3 discloses a device that controls the rotation speed of a fan that separates paper so that the paper has an optimum flying height regardless of the paper type and paper thickness. In this method, the distance from the belt surface of the conveyor belt to the sheet lifted is recognized by a distance measuring sensor, and the rotational speed of the separation fan is controlled to control the amount of air blown based on the distance measurement sensor.

  In a paper feeding mechanism using air, air is usually adjusted only by controlling the rotational speed of the fan, that is, the air volume is increased or decreased by adjusting the rotational speed of the fan. Here, not only the air volume but also the air pressure is an important factor in handling the paper. In general, the air flow rate has an effect on the floating of the paper, and the air pressure has an effect on the paper handling.

  However, with the conventional paper feed mechanism, when the paper cannot be fully handled, it is only possible to cope with it by increasing the air volume. For this reason, when the air flow rate is increased, a paper feeding failure due to the paper floating too much, for example, non-paper feeding or double feeding occurs.

  Therefore, an object of the present invention is to provide a paper feeding device that can adjust not only the air volume but also the wind pressure and can handle many types of paper.

  The sheet feeding device according to the present invention is a sheet feeding device including a blowing unit that discharges air to float at least one of a side surface and a front surface of the stacked sheet bundle, and the blowing unit discharges the sheet. An air flow path through which air flows by connecting an air intake port for taking in air and a blow-out port for blowing out the air, and a plurality of fans arranged side by side in a direction along the flow direction of the air flow in the air flow path, A bypass passage for passing air from downstream that does not pass through the selected fan among the plurality of fans, an open / close door disposed in the bypass passage for adjusting the amount of air flowing through the bypass passage, and the opening and closing And an opening / closing door driving means for driving the door.

  According to the present invention, since not only the air volume but also the wind pressure can be adjusted, it is possible to quickly cope with many types of paper.

1 is a schematic diagram illustrating an image forming apparatus to which a paper feeding device according to an embodiment of the present invention can be applied. 2 is a block diagram illustrating a configuration of the sheet feeding device. FIG. It is a schematic diagram which shows the structure of the paper feeder. FIG. 2 is a perspective view illustrating an internal configuration of the sheet feeding device. FIG. 2 is a perspective view illustrating an internal configuration of the sheet feeding device. FIG. 6 is a schematic diagram illustrating a sheet bundle upper surface detection operation by a sheet upper surface position detection unit in the sheet feeder. FIG. 6 is a schematic diagram illustrating a sheet bundle upper surface detection operation by a sheet upper surface position detection unit in the sheet feeder. It is sectional drawing which shows the air blower of the paper feeding apparatus which concerns on Embodiment 1 of the paper feeding apparatus which concerns on this invention. It is sectional drawing which shows operation | movement of the air blower. It is sectional drawing which shows the air blower of the paper feeding apparatus which concerns on Embodiment 2 of the paper feeding apparatus which concerns on this invention.

  A sheet feeding device and an image forming apparatus according to an embodiment for carrying out the present invention will be described. Note that the dimensions, materials, shapes, and relative arrangements of the components of the sheet feeding device and the image forming apparatus described in the following embodiments can be changed as appropriate according to the configuration of the apparatus to be applied and various conditions. Therefore, unless there is a specific description, it is not intended to limit only to them.

  FIG. 1 is a schematic diagram illustrating an image forming apparatus to which a sheet feeding device according to an embodiment can be applied. The image forming apparatus 100 includes an image forming apparatus main body 110 that includes an image forming unit and forms an image, and a paper feeding device 10 connected to one side surface of the image forming apparatus main body 110. The image forming apparatus main body 110 is, for example, an electrophotographic color printer or a multifunction peripheral, and forms an image on a sheet supplied from the sheet feeding apparatus 10. The image forming apparatus main body 110 is not limited to an electrophotographic type, and may be of another type such as an ink jet type. Furthermore, although the image forming apparatus main body 110 and the image forming apparatus 100 are described as separate apparatuses, the paper feeding apparatus may be disposed in the image forming apparatus main body.

  FIG. 2 is a block diagram showing the configuration of the paper feeding device, and FIG. 3 is a schematic diagram showing the configuration of the paper feeding device. As shown in FIGS. 2 and 3, the sheet feeding device 10 includes a blower 40 that is a blowing unit, a suction belt unit 12, a sheet upper surface position detecting unit 13, a driving unit 17 that drives the tray bottom plate 16, a driving control unit 18, A calculation unit 19, a counting means 20, and an information input unit 21 are provided.

  The blower 40 serving as an air supply mechanism blows paper floating air and causes the paper to float up to just below the suction belt unit 12. A suction belt unit 12 serving as a conveyance belt mechanism conveys the topmost sheet one by one from a sheet bundle S composed of a plurality of stacked sheets. Thereby, the air blower 40 and the suction belt unit 12 constitute a transport mechanism. The transport mechanism is not limited to this example, and may be another type of mechanism. Other methods include a friction separation method, for example, a combination of a feed roller and a pad, a combination of a feed roller and a reverse roller (FRR method), and a roll feeder method (RF method). Moreover, an electrostatic adsorption system, an air adsorption system, etc. can also be adopted.

  A sheet bundle S is stacked on the tray bottom plate 16 and is moved up and down in the vertical direction by the driving means 17. The sheet upper surface position detection means 13 includes a sheet contact member 14 and a position sensor 15. The sheet contact member 14 contacts the uppermost sheet S1 of the sheet bundle S stacked on the tray bottom plate 16 and swings up and down according to the position of the upper surface Sa of the sheet bundle S. The position sensor 15 detects the vertical position of the paper contact member 14. The driving unit 17 drives the tray bottom plate 16 up and down under the control of the driving control unit 18.

  Based on the detection position detected by the paper upper surface position detection means 13, the drive control means 18 sets a predetermined value “H”, which is a predetermined value for the distance between the uppermost surface of the sheet bundle S of the tray bottom plate 16 and the suction belt unit 12. Drive to be. Further, when the thickness reduction amount of the sheet bundle S stacked on the tray bottom plate 16 reaches a predetermined value, the drive control unit 18 causes the driving unit 17 to raise the tray bottom plate 16 by a predetermined value. Further, the drive control unit 18 causes the sheet upper surface position detection unit 13 to execute a sheet upper surface position detection operation again when the number of detected sheets reaches a predetermined number.

  Next, the arrangement state of each part in the paper feeder 10 will be described. As shown in FIG. 3, the paper feeder 10 blows air from the blower 40 toward the front end surface of the sheet bundle S stacked on the tray bottom plate 16, and the air is fed to the uppermost sheet S <b> 1 by the suction belt unit 12. To the height of. Then, the sheet S1 is adsorbed by the operation of the air suction means 26. Here, the sheet adsorbed to the suction belt unit 12 is not limited to a single sheet, and may be adsorbed with the sheets in close contact with each other.

  Accordingly, air is blown by the blower means 25 provided on the side fence 23 to separate the sheet adsorbed on the suction belt unit 12 into one sheet. Thereafter, the sheet S1 is conveyed to the image forming apparatus main body 110 by the suction belt unit 12, and image formation is performed. A paper damming member 27 is disposed between the blower 40 and the paper bundle S, and prevents paper other than the uppermost paper S1 from being conveyed. In the figure, reference numeral 28 denotes a conveying roller pair, and reference numeral 29 denotes a paper sensor.

  Further, in order to measure the distance “h” between the upper surface Sa of the sheet bundle S and the suction belt unit 12, the tray is provided with a sheet upper surface position detecting means 13 for contacting the upper surface Sa of the sheet bundle S and detecting the height of the sheet. It has been. The sheet upper surface position detecting means 13 includes a swingable sheet contact member 14 and a position sensor 15 that detects the swinging state of the sheet contact member 14. For example, a transmissive sensor is used for the position sensor 15.

  4 and 5 are perspective views showing the internal configuration of the sheet feeding device. The paper feeding device 10 includes a paper feeding tray 22 having a tray bottom plate 16 on which the paper bundle S is stacked. The suction belt unit 12 is disposed above the paper feed tray 22.

  In the paper feed tray 22, side fences 23 are provided on both sides for guiding the side surface in the width direction (direction perpendicular to the paper feed direction) of the sheet bundle S stacked on the tray bottom plate 16. An end fence 24 is provided on the rear side of the sheet bundle S of the sheet feeding tray 22 to hold the rear end surface of the sheet. In the side fence 23, an air outlet 25a of the blower means 25 for judgment is arranged.

  FIG. 5 shows the suction belt unit 12 removed from the paper feeder 10. A blower 40 is disposed directly below the suction belt unit 12. The side fence 23 is provided with a blower means 25 for judgment.

  Next, the upper surface detection of the sheet bundle S by the paper upper surface position detecting means 13 in the paper feeder 10 will be described. 6 and 7 are schematic views showing the operation of detecting the upper surface of the sheet bundle S of the sheet feeding device. In these cases, when the sheet bundle S is set on the tray bottom plate 16, the distance dimension “h” between the upper surface Sa of the sheet bundle S stacked on the tray bottom plate 16 and the suction belt unit 12 is determined in advance from the value “h ′”. The operation up to the specified value “H” is shown.

  FIG. 6 shows a state in which when the sheet bundle S is set on the tray, the distance between the upper surface Sa of the sheet bundle S and the suction belt unit 12 is “h ′” (> “H”). In this state, the sheet contact member 14 is rotated downward about the fulcrum, and the position sensor 15 does not detect anything.

  Here, when the tray bottom plate 16 is lifted by the driving means 17, as shown in FIG. 7, the sheet contact member 14 contacts the upper surface Sa of the sheet bundle S and rotates upward about the fulcrum to position the sheet. The sensor 15 detects the paper contact member 14. In this state, the distance dimension “h” between the upper surface Sa of the sheet bundle S and the suction belt unit 12 is the specified value “H”. At this time, the press of the paper contact member 14 to the paper bundle S is only a few grams, and it is possible to prevent the paper from being scratched or marked.

<Embodiment 1>
Next, the paper feeding device according to the first embodiment of the paper feeding device according to the present invention will be described. In the first embodiment, the blower 40 has the following structure. FIG. 8 is a cross-sectional view showing the air blowing means of the paper feeding device according to the first embodiment of the paper feeding device according to the present invention, and FIG. 9 is a cross-sectional view showing the operation of the air blowing means.

  The blower 40 discharges air to at least one of the side surface and the front surface of the stacked paper bundle S to float the paper. The blower 40 is provided with an air inlet 47 for taking in discharged air and an outlet 48 for blowing out air.

  The blower 40 also includes an air flow path 45 through which air flows by connecting the air inlet 47 and the outlet 48. In the air flow path 45, a plurality of upstream fans 41 arranged in the direction along the air flow direction, that is, two upstream fans 41 and downstream fans 42 arranged downstream are arranged as two fans. Prepare. The upstream fan 41 is provided so as to block the air inlet 47. For this reason, the air flowing in from the upstream fan 41 passes through the upstream fan 41.

  The air flow path 45 has a large cross-sectional area from the location of the upstream fan 41 toward the downstream fan 42, and a bypass flow path 46 is formed in parallel with the downstream fan 42 that is the selected fan. Air from downstream is passed through the outlet 48 without passing through the downstream fan 42.

  Further, the blower 40 includes an opening / closing door 43 that is disposed in the bypass flow path 46 and adjusts the amount of air flowing through the bypass flow path 46. The opening / closing door 43 is driven to open / close by an opening / closing door driving means 49. Information about the device environment, such as the type of the sheets of the sheet bundle S stacked on the sheet feeding device 10, the sheet conveyance timing, and the temperature and humidity of the apparatus, is input to the opening / closing door driving means 49.

  The opening / closing door 43 is rotationally driven around the rotation fulcrum 44 and its opening degree is adjusted by the opening / closing door driving means 49. The opening / closing door driving means 49 can be driven by, for example, an electric motor, a solenoid or the like, but is not particularly limited to this mechanism.

  Next, the operation of the blower 40 will be described. The blower 40 according to the first embodiment opens and closes the open / close door 43 based on data regarding the paper type, paper transport timing, and apparatus environment input to the open / close door driving means 49.

  As shown in FIG. 8, when the open / close door 43 is opened so that air can pass through the bypass passage 46, the air from the upstream fan 41 is further pushed out by the downstream fan 42 and also from the bypass passage 46. It flows upstream. For this reason, the air volume from the blower outlet 48 can be increased. It is known that the air volume can be increased by operating the upstream fan 41 and the downstream fan 42 and opening the bypass passage 46.

  On the other hand, when the bypass passage 46 is closed with the open / close door 43 closed as shown in FIG. 9, all the air from the upstream fan 41 flows into the downstream fan 42, and the wind pressure can be further increased by the downstream fan 42. . Thereby, the wind pressure of air can be increased, without increasing the air volume from the blower outlet 48 of the air blower 40. FIG. The use of air with increased wind pressure in this way can improve the handling force. It is known that the wind pressure can be increased by operating the upstream fan 41 and the downstream fan 42 in the state shown in FIG.

  The open / close door driving means 49 changes the open / close state of the open / close door 43 based on the type of paper. The change can be automatically made according to the input paper type. In general, for a large size paper, a large air volume is required to float the paper. In this case, when the air volume cannot be covered only by the output of the upstream fan 41, the opening / closing door driving means 49 drives the opening / closing door 43 to open the bypass passage 46. As a result, the air volume from the air outlet 48 is increased, and the sheet can be floated even in a large size.

  Further, in the paper feeding mechanism using air, the paper does not have to be sufficiently lifted when the paper is handled, but the paper needs to be lifted to an appropriate position during paper feeding. If the paper has not floated to the proper position, there is a high possibility that non-feed will occur.

  Therefore, the opening / closing door driving means 49 switches between the state shown in FIG. 8 and the state shown in FIG. 9 in accordance with the sheet feeding timing. This makes it possible to achieve both paper floating properties and paper handling properties. Specifically, the case where the paper size is not sufficient for the large size paper described above will be described.

  For example, the opening / closing door driving means 49 drives the opening / closing door 43 during the paper separation before feeding paper, closes the bypass flow path 46 (see FIG. 9), sufficiently spreads the paper, and immediately before feeding paper. The bypass flow path 46 is in an open state (see FIG. 8). As a result, the sheet is lifted to an appropriate position and fed. After feeding the paper, the bypass flow path 46 is closed again to separate the paper. In this way, by opening and closing the bypass flow path 46 for each sheet, it is possible to perform good sheet feeding even for a sheet that has high adhesion and is difficult to float.

  In general, it is known that coated paper or the like has a high adhesive force when the environment is high temperature and high humidity. That is, when the temperature and humidity are increased, poor paper feeding occurs frequently. For this reason, when the adhesion force of the paper increases in a high-temperature and high-humidity environment, the opening / closing door driving means 49 closes the bypass flow path 46 and increases the wind pressure. As a result, the handling performance is improved, and there is no problem with paper feeding.

  Further, the opening / closing door driving means 49 can adjust the opening degree of the opening / closing door 43 as well as the two states of the bypass channel 46 being opened and closed. Thereby, it is possible to adjust the balance between the air volume from the blower 40 and the wind pressure, and thus it is possible to cope with various paper separations.

<Embodiment 2>
Next, a paper feeding device according to a second embodiment of the paper feeding device according to the present invention will be described. FIG. 10 is a cross-sectional view showing a blower used in the paper feeding device according to the second embodiment of the paper feeding device according to the present invention. The blower 50 of the paper feeding device according to the second embodiment discharges air to at least one of the side surface and the front surface of the stacked paper bundle S to float the paper. The blower 50 includes an air inlet 57 for taking in air to be discharged and an outlet 58 for blowing out the air.

  The blower 50 includes an air flow path 55 through which air flows by connecting the air inlet 57 and the outlet 58. In the air flow path 55, the upstream fan 51 and the downstream fan 52 are provided as a plurality of, ie, two fans, arranged side by side in the direction along the air flow direction. The air flow path 55 is formed so that its cross-sectional area decreases from the location where the upstream fan 51 is disposed toward the downstream fan 42. A bypass passage 56 is formed in the air passage 55 in parallel with the upstream fan 51, and the bypass passage 56 includes a bypass air suction port 60.

  Air from the bypass channel 56 flows into the downstream fan 52 without passing through the downstream fan 52. Further, the bypass channel 56 includes an open / close door 53 that adjusts the amount of air flowing through the bypass channel 56. The opening / closing door 53 is driven to open / close by the opening / closing door driving means 59. Information about the sheet type of the sheet bundle S stacked on the sheet feeding device 10, the conveyance timing, and the rotation state of each fan is input to the opening / closing door driving unit 59.

  In this blower 50, when a predetermined time has elapsed after the downstream fan 52 starts driving, the opening / closing door driving means 59 rotates the opening / closing door 53 around the rotation fulcrum 54, and from the bypass flow path 56. Of the air flows into the downstream fan 52. Then, after the rotational speed of the downstream fan 52 reaches a predetermined value, the air blowing by the upstream fan 51 is controlled. The upstream fan 51 can be driven from a stage earlier in time than when the sheet feeding device 10 starts to operate. As the upstream fan 51, a fan whose output is lower than that of the downstream fan 52 can be used. Further, when the target air flow rate and air pressure may be small depending on the paper type and paper size, the open / close door 53 can be opened from the beginning without using the upstream fan 51.

10: paper feeding device 12: suction belt unit 13: paper upper surface position detection means 14: paper contact member 15: position sensor 16: tray bottom plate 17: drive means 18: drive control means 19: arithmetic unit 20: counting means 21: information Input section 22: paper feed tray 23: side fence 24: end fence 25: blower means 26: air suction means 27: stop member 28: reference numeral 29: reference numeral 40: blower 41: upstream fan 42: downstream fan 43: open / close door 44: Rotation fulcrum 45: Air flow path 46: Bypass flow path 47: Air inlet 48: Air outlet 49: Opening / closing door driving means 50: Blower 51: Upstream fan 52: Downstream fan 53: Opening / closing door 54: Rotation fulcrum 55: Air channel 56: Bypass channel 57: Air inlet 58: Air outlet 59: Opening / closing door driving means 60: Bypass air inlet 100: Image forming apparatus 1 0: the main body of the image forming apparatus

JP-A-7-196187 JP-A-2005-272019 JP-A-7-89625

Claims (10)

In a paper feeding device provided with a blowing unit that discharges air to at least one of a side surface and a front surface of a stacked paper bundle to float the paper,
The air blowing means connects an air inlet port for taking in the discharged air and an air outlet port for blowing out the air, and an air flow path through which air flows,
A plurality of fans arranged side by side in a direction along the air flow direction in the air flow path;
A bypass flow path for passing air from downstream that does not pass through the selected fan among the plurality of fans;
An open / close door disposed in the air flow path for adjusting the amount of air flowing through the bypass flow path;
An opening / closing door driving means for driving the opening / closing door;
A sheet feeding device comprising: Two fans are arranged,
2. The sheet feeding device according to claim 1, wherein the bypass passage allows air that does not pass through an upstream fan of the two fans to pass therethrough. 3. Two fans are arranged,
2. The sheet feeding device according to claim 1, wherein the bypass passage is configured to pass air that does not pass through a downstream fan of the two fans.   4. The sheet feeding device according to claim 1, wherein the opening / closing door driving unit drives the opening / closing door based on a type of paper to be fed. 5.   4. The sheet feeding device according to claim 1, wherein the opening / closing door driving unit drives the opening / closing door based on a sheet conveyance timing. 5.   The sheet feeding device according to any one of claims 1 to 3, wherein the opening / closing door driving unit drives the opening / closing door based on an apparatus environment.   4. The sheet feeding device according to claim 1, wherein the opening / closing door driving unit drives the opening / closing door based on a rotation state of a fan. 5.   The sheet feeding device according to any one of claims 1 to 6, wherein the opening / closing door driving unit can adjust a degree of opening / closing of the opening / closing door.   The sheet feeding device according to claim 3, wherein the air volume of the downstream fan is smaller than the air volume of the upstream fan. An image forming apparatus comprising: the sheet feeding device according to claim 1; and an image forming unit that forms an image on a sheet supplied by the sheet feeding device.