JP2006193262A - Sheet feeder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet feeder capable of restricting the generation of sheet feeding error due to moisture. <P>SOLUTION: The sheet feeder is provided with a sheet housing means for housing stacked sheets, and feeds the sheets housed in the sheet housing means one by one from the sheet housing means. This sheet feeder is also provided with a first blow-off opening for blowing dry air toward edges of a plurality of sheets housed in the sheet housing means and a second blow-off opening for blowing out dry air in a direction avoiding the sheets housed in the sheet housing means. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sheet feeding device that includes sheet storage means for storing stacked sheets and that feeds sheets stored in the sheet storage means one by one from the sheet storage means.

  2. Description of the Related Art Conventionally, a printer having sheet storage means for stacking and storing sheets such as recording paper, and forming an image on a sheet transported through a transport path for transporting a sheet fed from the sheet storage means An image forming apparatus including a sheet feeding device such as the above is known.

  In such a sheet feeding device of the image forming apparatus, there is a problem of double feeding due to close contact between the sheets stacked in the sheet storage unit.

Therefore, for the purpose of dehumidifying the upper layer of the stacked sheets, the proposal is to reduce the adhesion between the sheets due to wetting by blowing dry air toward the upper surface of the uppermost sheet. (See Patent Document 1).
JP-A-6-32473

  However, in the above proposal, if the waiting time of the uppermost sheet in the sheet storage means becomes longer, dehumidification of the uppermost sheet becomes excessive, and warping may occur in the uppermost sheet, resulting in trouble in conveyance. There is.

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a sheet feeding apparatus that is devised to suppress occurrence of a sheet conveyance error due to wetting.

In order to achieve the above object, a sheet feeding apparatus according to the present invention comprises:
In a sheet feeding device that includes sheet storage means for storing stacked sheets, and that feeds sheets stored in the sheet storage means one by one from the sheet storage means,
A first air outlet for blowing dry air toward the edges of the plurality of sheets accommodated in the sheet accommodating means;
And a second air outlet for blowing dry air in a direction avoiding the sheet accommodated in the sheet accommodating means.

  In the sheet feeding apparatus according to the present invention, the dry air is blown toward the edges of the plurality of sheets stored in the sheet storage unit to release the adhesion between the sheets, and dehumidification of the sheets in the sheet storage unit is conventionally performed. Indirect while suppressing local dehumidification by the dry air blown away in the direction avoiding the sheet accommodated in the sheet accommodating means instead of the upper surface of the uppermost sheet among the sheets accommodated in the sheet accommodating means Has been made. Therefore, according to the sheet feeding apparatus of the present invention, it is possible to suppress occurrence of a sheet conveyance error due to wetting.

  Here, the sheet storage means stores the sheet between a feeding position for storing the sheet when the sheet is fed from the sheet storage means and a retracted position deviated from the feeding position. The position is changed, the first air outlet blows dry air toward the edges of the plurality of sheets accommodated in the feeding position, and the second air outlet discharges the dry air. In a preferred embodiment, the sheet is blown out in a direction avoiding the sheet accommodated in the retracted position, and the first outlet and the second outlet are a common outlet.

  In this way, when the sheet is accommodated in the feeding position where the sheet is accommodated when the sheet is fed, the drying air is blown out to the edges of the plurality of sheets at the feeding position. When the seat is stored in the retracted position, the blowout outlet blows dry air in a direction avoiding the sheet stored in the retracted position, and simplification, small space, and cost reduction are possible by combining the use of the air outlet. Become.

  The sheet accommodating means accommodates a plurality of sizes of sheets accommodated in a stacked state, and the second blow-out port accommodates dry air in the sheet accommodating means. It is also preferable to blow out in a direction avoiding at least the smallest size sheet.

  As described above, when the second blow-out opening accommodates the smallest size sheet in the sheet accommodation means, the second blowing outlet blows dry air in a direction avoiding the smallest size sheet in the sheet accommodation means. In addition, since feeding is performed more quickly than in the case of a large size sheet, it is possible to cover the point that the time for directly releasing the close contact between the sheets is reduced.

Here, a humidity sensor for detecting humidity,
It is preferable that the second air outlet includes a dry air and a control unit that changes humidity according to a detection result from the humidity sensor.

  In this manner, by detecting the humidity that affects the close contact state between the sheets and blowing out the drying air according to the detection result, it is possible to further suppress the occurrence of a sheet conveyance error due to wetting.

  According to the sheet feeding apparatus of the present invention, it is possible to suppress sheet conveyance errors that occur due to wetting.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 is a schematic configuration diagram of an image forming apparatus provided with a first embodiment of a sheet feeding apparatus of the present invention.

  A printer 1 illustrated in FIG. 1 is a monochrome printer that includes a sheet feeding device 11, an image forming unit 210, a fixing unit 310, and a sheet conveying unit 410, and forms a black and white image on a sheet.

  The image forming unit 210 includes a photoconductor roll 216 rotating in the direction of arrow A, a charger 214 rotating in the direction of arrow B for applying a predetermined charge to the photoconductor roll 216, the external terminal 2, and the image reading device 3. A receiving unit 211 that receives transmitted image data, an image data processing unit 212 that processes image data received by the receiving unit 211, and a photoreceptor roll 216 according to the image data processed by the image data processing unit 212. A developing roll 2151 that develops the electrostatic latent image formed on the surface of the photoreceptor roll and rotates in the direction of arrow C while holding the toner. A developing unit 215 that develops the electrostatic latent image formed on the surface of the photoreceptor roll with toner, and a toner image formed on the surface of the photoreceptor roll 216 via the sheet conveyance path 420. Transferred onto feed has been have sheets, and a transfer roll 217 that rotates in the arrow D direction.

  The fixing unit 310 fixes the toner image onto the sheet by conveying the sheet onto which the toner image has been transferred while nipping between the heating roll 311 and the pressure roll 312.

  The sheet conveying unit 410 includes a conveying roll 411 and a feeding roll 412 for feeding a sheet that has been fixed onto the upper surface of the printer 1.

  The sheet feeding device 11 includes a sheet storage unit 12 that stores stacked sheets, fans 13 a and 13 b that blow dry air from the peripheral wall side of the sheet storage unit 12 toward the edges of the stacked sheets, and sheets. The sheet feeding unit 14 feeds a sheet from the sheet storage unit 12 in order to feed the sheet from the storage unit 12 to the sheet conveyance path 420.

  2 is a top view and a cross-sectional view of the sheet feeding apparatus shown in FIG.

  FIG. 2A shows a top view of the sheet feeding apparatus 11, in which a sheet storage unit 12 that stores the sheet 100, and a bottom plate 121 disposed at the bottom of the sheet storage unit 12. The nudger roll 141 that rotates in contact with the sheet positioned at the top of the sheet accommodated in the sheet accommodating unit 12, which is a component of the sheet feeding unit 14, and the sheet conveying path side of the nudger roll 141 ( 1 shows a feed roll 142 that feeds a sheet fed by a nudger roll 141 to a sheet conveyance path 420 together with a retard roll described later.

  2A shows a humidity sensor 15 that is a component of the sheet feeding apparatus 11, fans 13a and 13b that blow dry air in a direction orthogonal to the direction in which the sheet 100 is fed, and the humidity sensor 15. , A dehumidifying means provided in the first fan 13a and the second fan 13b for controlling the humidity of the drying air by raising the temperature of the air, here the first heater 131a, the second heater 131b, In addition, a state in which the control unit 10 that controls the operation of the sheet feeding unit 14 is provided is shown. The drying air may be controlled by controlling the air volume based on the outputs of the first fan 13a and the second fan 13b.

  Further, FIG. 2A shows a side guide 16 and an end guide 17 that are movable in directions orthogonal to each other in the sheet storage means.

  These side guides 16 and end guides 17 are for moving according to the size of the sheets to be accommodated and for stabilizing the stacked sheets by pressing the sheets against the wall surfaces 12a and 12b.

  FIG. 2B shows a retard roll 143 that is a component of the sheet feeding unit 14 and that is positioned below the feed roll 142 and contacts the feed roll 142 to prevent double feeding of sheets.

  Although not shown, the sheet feeding unit 14 has a solenoid that rotates the nudger roll 141 toward the sheet 100 around the central axis of the feed roll 142 and a nudger roll 141 that rotates toward the sheet. Is a level that is an optical sensor that detects whether or not the height at which the sheet is in contact with the sheet is a preset height for feeding the sheet, that is, whether or not the sheet height is appropriate. A sensor is also a component.

  In FIG. 2B, the sheet storage position when the sheet feeding instruction is not yet issued from the printer 1 to the sheet feeding apparatus 11 (hereinafter, this position is referred to as a retracted position). At this time, from the first air outlet 132a of the first fan 13a and the second air outlet 132b of the second fan 13b, toward the space 20 avoiding the seat accommodated in the retracted position. Then, dry air corresponding to the humidity information from the humidity sensor 15 is blown. When a sheet feeding instruction is issued from the printer 1, the sheet feeding device 11 activates a solenoid to bring the nudger roll 141 into contact with the upper surface of the sheet 100 and is disposed at the bottom of the sheet storage unit 12. The motor of the bottom plate 121 is instructed to start, and raises the seat accommodation position.

  In FIG. 2C, the sheet storage position is a position where the sheet can be fed when the sheet feeding instruction is issued from the printer 1 (hereinafter, this position is referred to as a feeding position). The state of rising up to is shown. When the sheet storage position reaches the feeding position, the position of the nudger roll 141 that is in contact with the uppermost surface of the sheet 100 is also raised, and the height of the sheet is preset for feeding the sheet. The level sensor detects that the height has been reached. In response to this, the rising of the bottom plate 121 is stopped, and the dry air blown in accordance with the humidity information from the humidity sensor 15 from the first air outlet 132a and the second air outlet 132b is now Is sprayed to the edges of a plurality of sheets accommodated in the sheet accommodating means 12, and is used for releasing the adhesion between the sheets just before feeding. Thereafter, when the sheet feeding instruction is interrupted, the sheet storage unit 12 is lowered to the retracted position again, and the blowing of the drying air to the space 20 is continued. The mechanism for raising the bottom plate 121 and the like is a known technique and is not directly related to the present invention, so the description thereof is omitted.

  In the sheet feeding device 11 provided in the printer 1, the sheet is stored in the retracted position shown in FIG. 2A until the sheet feeding instruction is issued after the printer 1 is turned on. In a state where the air is discharged, dry air corresponding to humidity information from the humidity sensor 15 is supplied to the space 20 avoiding the seat from both the first air outlet 132a of the first fan 13a and the second air outlet 132b of the second fan 13b. It comes to blow out. In addition, when the humidity information detected by the humidity sensor 15 indicates high humidity, the control unit 10 raises the temperature of each heater to increase the relative humidity of the air blown out, because there is a possibility that the degree of adhesion between the sheets may increase. If the humidity is low, the heater temperature is lowered, or the heater is turned off, and the relative humidity of the air blown out is controlled to be reduced or not lowered. Further, when the humidity is high, the fans may be instructed to blow at a high output, and when the humidity is low, the fans may be instructed to blow at a low output or turn off the output.

  When the sheet feeding instruction from the printer 1 is issued to the sheet feeding device 11, the sheet storage position is changed to the feeding position shown in FIG. As a result, the drying air for humidity control from both the air outlet 132a of the first fan 13a and the air outlet 132b of the second fan 13b is now directed toward the edges of the plurality of sheets accommodated in the sheet tray 12. It is possible to simplify, reduce the space, and reduce the cost. In other words, in the printer 1, when a sheet feeding instruction is issued, the sheets are released from contact with each other by the dry air blown toward the edges of the plurality of sheets, and the sheets stored in the sheet storing means are stored. Dehumidification in the sheet storage means is indirectly performed while suppressing local dehumidification by the dry air blown in a direction avoiding the above. Therefore, according to the printer 1, it is possible to suppress occurrence of a sheet conveyance error due to wetting at a low cost.

  FIG. 3 is a flowchart of a routine executed in the sheet feeding device provided in the printer.

  The routine shown in FIG. 3 is a routine that is executed in the sheet feeding device 11 when the printer 1 is turned on. In step S1, the acquisition of humidity information from the humidity sensor 15 is instructed. In step S <b> 2, an instruction is given to blow dry air at a humidity or an air volume corresponding to the acquired humidity information while the sheet is stored at the retracted position. In step S3, it is determined whether or not a sheet feeding instruction has been issued. If it is determined in step S3 that there is no instruction, the process returns to step S1, and if it is determined that there is an instruction, the process proceeds to step S4. In step S4, the solenoid is instructed to turn on, and in step S5, the motor of the bottom plate 121 is instructed to rotate in the direction in which the bottom plate 121 is raised. In step S6, it is determined whether or not the level sensor is turned off due to the rising of the bottom plate 121, that is, whether or not the sheet has reached a feedable height. If it is determined in step S6 that the sheet has not reached the predetermined height, the process returns to step S5. If it is determined that the sheet has reached, the process proceeds to step S7. In step S7, the motor of the bottom plate 121 is instructed to stop. In step S8, the nudger roll 141 is instructed to perform a feeding operation. In step S9, it is determined whether or not the feeding operation has been completed. If it is determined that the feeding operation has not been completed, step S9 is repeated. If it is determined in step S9 that the process has been completed, the process proceeds to step S10 to determine whether an instruction for feeding the next sheet has been issued. If it is determined in step S10 that no instruction has been issued, the process proceeds to step S11, where the motor of the bottom plate 121 is instructed to rotate in the downward direction by a predetermined amount, and the sheet storage position is moved from the feeding position to the retracted position. Change to Then, it returns to step S1. On the other hand, if it is determined in step S10 that the next feeding instruction has been issued, the process proceeds to step S12, in which the level sensor is turned off, that is, the sheet height is set to a predetermined height by sheet feeding. It is determined whether or not it has been lowered. If it is determined in step S12 that it is lowered, the process proceeds to step S13, the motor of the bottom plate 121 is instructed to rotate in the upward direction, and step S12 is repeated until the height reaches a predetermined height. If it is determined in step S12 that the height is at the predetermined height, the process proceeds to step S14, the motor of the bottom plate 121 is instructed to stop, and then the process returns to step S8.

  FIG. 4 is a diagram illustrating another aspect of the sheet feeding device provided in the printer.

  The only difference between the sheet feeding device 21 shown in FIG. 4 and the above-described sheet feeding device 11 is that the fan deployment position has moved to the position where the sheet is fed, and thus detailed description thereof will be omitted. However, even if the sheet feeding device 21 having such a mode is provided, according to the printer 1, local dehumidification can be avoided and occurrence of a sheet conveyance error due to the wetting can be suppressed.

  Next, a second embodiment of the sheet feeding apparatus of the present invention will be described.

  FIG. 5 is a schematic configuration diagram of a sheet feeding device provided in the printer. In the following members, the same reference numerals as those in FIG. 2 are attached to the same types of members as in FIG.

  The sheet feeding device 31 shown in FIG. 5 includes, as a constituent element, a sheet storage unit 12 that accommodates sheets of a plurality of sizes (A3 plate, A4 plate, and B5 plate) that are stored in a stacked state. Shows a state in which the sheet 100 of the smallest size (B5 size) among the sizes that can be accommodated is accommodated. The size of the sheet stored in the sheet storing means 12 can be recognized by the control unit 10 based on the position information of the side guide 16 and the end guide 17. Further, the description of FIG. 5A is the same as the description of FIG.

  In the sheet feeding apparatus 31 shown in FIG. 5, unlike the feeding measures 11 and 21 of the first embodiment, the sheet is accommodated in the feeding position as shown in FIG. 5B immediately after the power is turned on. The first fan 13a blows dry air having a humidity or an air volume according to the humidity information detected by the humidity sensor 15 on the edges of the plurality of sheets accommodated at the feeding position. On the other hand, the second fan 13b blows dry air into the space 20 in a direction avoiding the smallest size sheet (B5 plate) accommodated in the sheet accommodating means 12.

  In the printer including the sheet feeding device 31, the first fan 13a blows dry air toward the edges of the plurality of sheets stored in the sheet storage unit 12, and the second fan 13b avoids the sheet. Dry air is blown toward the facing space 20. Even in this way, the sheets are not closely adhered to each other, and the dehumidification of the sheets in the sheet storage unit suppresses the local dehumidification by the dry air blown out in the direction avoiding the sheet stored in the sheet storage unit. While being done indirectly. As a result, in a general printer, a small-sized sheet is more productive than a large-sized sheet because of the sheet spacing, but the time for directly solving the contact between the sheets is larger than in the case of a large-sized sheet. The reduced point can be covered with dry air blown in a direction avoiding the sheet stored in the sheet storing means. Therefore, even with this printer, local dehumidification can be avoided and occurrence of sheet conveyance errors due to wetting can be suppressed. Further, the drying air blown in the direction avoiding the sheet when feeding the small size sheet is effectively used as the drying air blown toward the edge of the sheet when feeding the large size sheet.

  FIG. 6 is a flowchart of a routine executed in the sheet feeding device provided in the printer.

  The routine shown in FIG. 6 is a routine that is executed in the sheet feeding device 31 when the printer is turned on. In step S21, the acquisition of humidity information from the humidity sensor 15 is instructed. In step S22, it is determined whether or not the accommodated sheet has a size that can avoid the second air outlet 132b. If it is determined in step S22 that the size is not the minimum size, the process proceeds to step S23 to execute a subroutine “normal process”, and then returns to step S21. This subroutine “normal process” is irrelevant to the present invention. Description is omitted. If it determines with it being the minimum size in step S22, it will progress to step S24 and will instruct | indicate the ventilation with the humidity according to the acquired humidity information or the air volume to the 2nd fan 13b. In step S25, the solenoid is instructed to turn on, and in step S26, the motor of the bottom plate 121 is instructed to rotate in the direction in which the bottom plate 121 is raised. In step S27, it is determined whether or not the level sensor is turned off due to the raising of the bottom plate 121, that is, whether or not the sheet has reached a feedable height. If it is determined in step S27 that the sheet has not reached the predetermined height, the process returns to step S26, and if it is determined that the sheet has reached, the process proceeds to step S28. In step S28, the motor of bottom plate 121 is instructed to stop. In step S29, the first fan 13a is instructed to blow with a humidity or an air volume according to the already acquired humidity information. In step S30, it is determined whether or not a sheet feeding instruction has been issued. If it is determined in step S30 that a feeding instruction has not been issued, the process returns to step S26. Proceeding to S31, the nudger roll 141 is instructed to perform a feeding operation. In step S32, it is determined whether or not the feeding operation has been completed. If it is determined that the feeding operation has not been completed, step S32 is repeated. If it is determined in step S32 that the process has been completed, the process proceeds to step S33, where it is determined whether an instruction for feeding the next sheet has been issued. If it is determined in step S33 that no instruction has been issued, the process returns to step S21. On the other hand, if it is determined in step S33 that the next feeding instruction has been issued, the process proceeds to step S34, in which the level sensor is turned off, that is, the sheet height is set to a predetermined height by sheet feeding. It is determined whether or not it has been lowered. If it is determined in step S34 that it is lowered, the process proceeds to step S35, the motor of the bottom plate 121 is instructed to rotate in the upward direction, and step S34 is repeated until the height reaches a predetermined height. If it is determined in step S34 that the height is a predetermined height, the process proceeds to step S36, the motor of the bottom plate 121 is instructed to stop, and then the process returns to step S31.

  FIG. 7 is a diagram illustrating another aspect of the sheet feeding device provided in the printer.

  The only difference between the sheet feeding device 41 shown in FIG. 7 and the above-described sheet feeding device 31 is that the fan deployment position has moved to the position where the sheet is fed, and thus detailed description thereof will be omitted. However, even if the sheet feeding device 41 having such an aspect is provided, according to this printer, it is possible to avoid local dehumidification and to suppress the occurrence of a sheet conveyance error due to the wetting.

  In this embodiment, the sheet feeding device in the image forming apparatus is used. However, the document feeding device in the document reading device may be used.

  In the present embodiment, the drying air is used as a heater, but it may be one using other dehumidifying means or exhaust from the image forming apparatus main body.

1 is a schematic configuration diagram of an image forming apparatus including a first embodiment of a sheet feeding apparatus according to the present invention. FIG. 2 is a top view and a cross-sectional view of the sheet feeding device illustrated in FIG. 1. 6 is a flowchart of a routine that is executed in a sheet feeding device provided in the printer. It is a figure which shows another aspect of the sheet feeding apparatus with which the printer was equipped. 1 is a schematic configuration diagram of a sheet feeding device provided in a printer. FIG. 6 is a flowchart of a routine that is executed in a sheet feeding device provided in the printer. It is a figure which shows another aspect of the sheet feeding apparatus with which the printer was equipped.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printer 10 Control part 11, 21, 31, 41 Sheet feeding apparatus 12 Sheet accommodating means 121 Bottom plate 13a, 13b, 13c, 13d Fan 132a, 132b, 132c, 132d Air outlet 14 Sheet feeding part 141 Nudger roll 142 Feed roll 143 Retard roll 15 Humidity sensor 16 Side guide 17 End guide

Claims (7)

In a sheet feeding apparatus that includes sheet storage means for storing stacked sheets, and that feeds sheets stored in the sheet storage means one by one from the sheet storage means,
A first air outlet for blowing dry air toward edges of a plurality of sheets accommodated in the sheet accommodating means;
A sheet feeding apparatus comprising: a second air outlet that blows dry air in a direction avoiding the sheet stored in the sheet storing means. The sheet storage unit changes the sheet storage position between a feeding position for storing the sheet when the sheet is fed from the sheet storage unit and a retracted position deviated from the feeding position. Is what
The first air outlet is configured to blow dry air toward edges of a plurality of sheets accommodated in the feeding position,
The second air outlet is configured to blow dry air in a direction avoiding the sheet accommodated in the retracted position,
The sheet feeding apparatus according to claim 1, wherein the first air outlet and the second air outlet are a common air outlet. The sheet accommodating means accommodates sheets of the same size in a stacked state, and accommodates a plurality of size sheets.
2. The sheet feeding apparatus according to claim 1, wherein the second blow-out port blows out the drying air in a direction avoiding at least the smallest size sheet accommodated in the sheet accommodating means. A humidity sensor for detecting humidity;
The sheet feeding apparatus according to claim 1, wherein the drying air at the second air outlet is controlled in accordance with a detection result from the humidity sensor.   5. The sheet feeding apparatus according to claim 4, wherein the humidity or the air volume of the dry air is controlled according to a detection result from the humidity sensor.   The sheet feeding apparatus according to claim 1, wherein the drying air is generated by a dehumidifying unit.   The sheet feeding apparatus according to claim 6, wherein the dehumidifying means is a heater.

Images