JP2011057407A - Paper feeder and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feeder capable of properly calculating the number of paper, while restraining electric power consumption. <P>SOLUTION: This paper feeder 23 includes a placing plate 31 capable of placing the paper and movable in the vertical direction, and supplies the paper to a predetermined place. The paper feeder 23 includes a first sensor 32 arranged on the upper side of the placing plate 31 and detecting a position of upper end paper 34a among the paper 34 placed on the placing plate 31 in a position for stopping the placing plate 31, a second sensor 33 arranged on the lower side of the placing plate 31 and detecting a position of lower end paper 34b among the paper 34 placed on the placing plate in the position for stopping the placing plate 31, and a number calculating means for calculating the number of paper placed on the placing plate 31 by the position of the upper end paper 34a detected by the first sensor 32 and the position of the lower end paper 34b detected by the second sensor 33. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a sheet feeding device and an image forming apparatus, and more particularly to a sheet feeding device capable of calculating the number of sheets and an image forming apparatus including such a sheet feeding device.

  The image forming apparatus includes a paper feeding device that supplies paper to an image forming unit that forms an image on the paper. The sheet feeder stores sheets in advance in a sheet cassette, and supplies the sheets one by one from the sheet cassette toward the image forming unit.

  Some image forming apparatuses include a sheet feeding device for placing and storing a sheet on the loading plate by providing a loading plate in the sheet cassette. In this case, the placing plate can be moved in the vertical direction, and the paper feeder moves the placing plate downward, and then places the paper on the placing plate by the user and stores it. . Thereafter, by moving the placement plate upward, the movement distance is measured, and the number of sheets placed on the placement plate is calculated. The mounting plate is moved by, for example, driving a motor.

  Further, as another technique for calculating the number of sheets placed on the placing plate, for example, JP-A-2-70627 (Patent Document 1) and JP-A-6-336352 (Patent Document 2). And JP-A-2003-192189 (Patent Document 3).

  According to Patent Literature 1, an upper end position detection sensor that detects the position of the upper end of the placed paper, a distance sensor that measures a distance from a predetermined position below the placement plate to the lower end of the placed paper, When the upper end position detection sensor detects the position of the upper end of the sheet, the distance sensor measures the distance to the lower end of the sheet and calculates the number of sheets.

  According to Patent Document 2, light is emitted toward the uppermost surface (upper end) of the placed paper, and the reflected light reflected by the uppermost surface is incident on the light receiving element as spot light. Accordingly, the number of sheets is calculated.

  According to Patent Document 3, the distance from a predetermined position above the placement plate to the upper end of the sheet and the distance to the lower end of the sheet are measured, and the difference is calculated to calculate the number of sheets. I am going to do that.

JP-A-2-70627 JP-A-6-336352 JP 2003-192189 A

  Here, in recent image forming apparatuses, it is preferable that operations relating to image formation can be performed while suppressing power consumption as much as possible from the viewpoint of saving power consumption. However, in the image forming apparatus as described above, even when calculating the number of sheets, it is necessary to drive the motor to move the mounting plate, and thus power is wasted. Particularly in the sleep mode, it is not preferable to drive the motor for calculating the number of sheets.

  Also in the technique disclosed in Patent Document 1, when the number of sheets is calculated, if the upper end of the sheet is located away from the upper end position detection sensor, the upper end of the sheet is moved to the position of the upper end position detection sensor. Must be moved.

  Further, since the technique disclosed in Patent Document 2 detects only the position of the uppermost surface of the paper, it cannot be applied to a paper feeding device of a type in which the placement plate can move.

  Further, in the technique disclosed in Patent Document 3, the distance to the upper end of the sheet and the distance to the lower end of the sheet are both measured from a predetermined position on the upper side of the placement board, and thus placed on the placement board. If the sheets are not aligned and are in a disjointed state, it is difficult to measure accurately.

  An object of the present invention is to provide a paper feeding device that can reduce power consumption and appropriately calculate the number of sheets.

  Another object of the present invention is to provide an image forming apparatus that can reduce power consumption and appropriately calculate the number of sheets.

  A paper feeding device according to the present invention is a paper feeding device that can place paper and has a placement plate that can move in the vertical direction, and supplies the paper to a predetermined location. The first detection means for detecting the position of the uppermost paper among the papers placed on the placement plate at the position where the placement plate is stopped on the upper side, and the lower side of the placement plate Of the paper placed on the placement plate, the second detection means for detecting the position of the lower end paper and the upper end detected by the first detection means at the position where the placement plate is stopped. And a sheet number calculating means for calculating the number of sheets placed on the placing plate based on the position of the sheet and the position of the lower end sheet detected by the second detecting means.

  Preferably, the detection unit includes: an irradiating unit that irradiates light on the paper placed on the placing plate; and a light receiving unit that receives the reflected light when the light irradiated by the irradiating unit is reflected by the paper. In addition, the position of the paper is detected based on the reflected light received by the light receiving means.

  More preferably, a portion of the mounting plate corresponding to a position where light is irradiated by the irradiation unit is provided with a through hole penetrating in the vertical direction.

  More preferably, the through-hole is different from the first through-hole provided in the portion corresponding to the position irradiated with light by the first detection means, and the second detection means emits light. 2nd through-hole provided in the part corresponding to the position irradiated.

  More preferably, of the sheets placed on the placing plate, a pickup roller that contacts the upper surface of the uppermost sheet and picks up the sheets one by one sequentially is provided, and the position where the placing plate is stopped is This is the position where the upper surface of the uppermost sheet of the sheets placed on the mounting plate is brought into contact with the pickup roller.

  More preferably, a fixed portion is provided below the mounting plate, and the position where the mounting plate is stopped is a position where the lower surface of the mounting plate is in contact with the fixing portion. .

  Another aspect of the present invention relates to an image forming apparatus including an image forming unit that forms an image on a sheet and a paper feeding device that supplies the sheet to the image forming unit. The paper feeding device has a placement plate that is capable of placing paper and is movable in the vertical direction, and is placed on the upper side of the placement plate at a position where the placement plate is stopped. The first detection means for detecting the position of the uppermost paper among the papers placed on the paper and placed on the placement plate at the position below the placement plate and stopped. Among the received sheets, the second detecting means for detecting the position of the lower end sheet, the position of the upper end sheet detected by the first detecting means, and the position of the lower end sheet detected by the second detecting means. And a sheet number calculating means for calculating the number of sheets placed on the placing plate.

  In the paper feeding device according to the present invention, at the position where the movable placing plate is stopped, the number of sheets placed on the placing plate is determined according to the detected position of the uppermost sheet and the position of the lower end sheet. calculate. Therefore, when calculating the number of sheets, it is not necessary to drive the motor to move the mounting plate. Further, in order to detect the position of the uppermost sheet from the upper side of the loading plate and the position of the lowermost sheet from the lower side of the loading plate, for example, even if the sheets are not aligned, Can be calculated. As a result, power consumption can be reduced and the number of sheets can be calculated appropriately.

  In the image forming apparatus according to the present invention, in the sheet feeding device, the position of the movable upper plate is stopped, and the uppermost sheet and the lower sheet are detected. The number of sheets placed is calculated. Therefore, when calculating the number of sheets, it is not necessary to drive the motor to move the mounting plate. Further, in order to detect the position of the uppermost sheet from the upper side of the loading plate and the position of the lowermost sheet from the lower side of the loading plate, for example, even if the sheets are not aligned, Can be calculated. As a result, power consumption can be reduced and the number of sheets can be calculated appropriately.

1 is a block diagram illustrating a configuration of a digital multifunction peripheral when an image forming apparatus according to an embodiment of the present invention is applied to the digital multifunction peripheral. FIG. 3 is a schematic cross-sectional view illustrating a part of a paper feeding device. It is a figure which shows the state which contacted the lower surface of the lift board to the fixing | fixed part. 6 is a flowchart illustrating an operation of a control unit when calculating the number of sheets placed on a lift plate when operating in a sleep mode. It is a figure which shows the state in which the paper is not mounted. 7 is a flowchart illustrating an operation of a control unit when calculating the number of sheets placed on a lift plate when operating in a normal mode. It is a figure which shows the state in which the paper is not mounted.

  Hereinafter, 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. FIG. 1 is a block diagram illustrating a configuration of a digital multifunction peripheral 10 when an image forming apparatus according to an embodiment of the present invention is applied to the digital multifunction peripheral 10. The digital multifunction machine 10 includes a paper feeding device 23 according to an embodiment of the present invention.

  Referring to FIG. 1, a digital multifunction peripheral 10 includes a control unit 11 that controls the entire digital multifunction peripheral 10, a DRAM 12 for writing and reading image data and the like, and an interface with a user in the digital multifunction peripheral 10. An operation unit 13, a document feeding device 14 for automatically transporting a document to a predetermined document reading position, and an image reading unit 15 for reading an image of the document conveyed by the document feeding device 14 with a scanner at a predetermined reading position. And an image forming unit 16 that forms an image on a sheet from a document read by the image reading unit 15 and a hard disk 17 that stores image data and the like. A FAX communication unit 18 connected to the public line 20 and a network IF (interface) for connecting to the network 21 Comprising a face) unit 19, a sheet feeder 23 for supplying paper to image forming unit 16.

  The digital multi-function peripheral 10 operates as a copier by forming an image in the image forming section 16 via the DRAM 12 using the document read by the image reading section 15. Further, the digital multifunction peripheral 10 forms an image in the image forming unit 16 via the DRAM 12 using the image data transmitted from the personal computer 22 connected to the network 21 through the network IF unit 19, thereby serving as a printer. Operate. Further, the digital multifunction peripheral 10 forms an image in the image forming unit 16 through the DRAM 12 using the image data transmitted from the public line 20 through the FAX communication unit 18, and also by the image reading unit 15. The image data of the read original is transmitted to the public line 20 through the FAX communication unit 18 to operate as a facsimile machine. That is, the digital multi-function peripheral 10 has a plurality of functions such as a copying (copying) function, a printer function, and a FAX function regarding image processing. Further, each function has functions that can be set in detail.

  The digital multi-function peripheral 10 is configured to have a normal mode and a sleep mode. In the normal mode, for example, since the temperature of the fixing roller is maintained at a temperature suitable for fixing a developer such as toner, an image can be formed immediately upon receiving an image formation request. Say that. Therefore, this is a mode with high power consumption.

  On the other hand, in the sleep mode, for example, since the temperature of the fixing roller is higher than the room temperature but kept lower than that in the normal mode, when the request for image formation is received, the image cannot be formed immediately and the fixing is performed. It means that it takes time to heat the roller to an appropriate temperature. Therefore, this mode consumes less power than the normal mode.

  In FIG. 1, thick arrows indicate the flow of image data, and thin arrows indicate the flow of control signals or control data.

  FIG. 2 is a schematic cross-sectional view showing a part of the paper feeding device 23. With reference to FIG. 2, the paper feeding device 23 will be described. The sheet feeding device 23 is a sheet cassette 30 that stores sheets 34, and a lift plate that is disposed inside the sheet cassette 30 and is mounted so as to stack a plurality of sheets 34 thereon. 31, a first sensor 32 disposed above the lift plate 31, a second sensor 33 disposed below the lift plate 31, and the paper 34 placed on the lift plate 31 A pickup roller 35 that contacts the upper surface of the upper sheet 34a and picks up the sheets one by one in sequence.

  The paper cassette 30 stores paper 34 therein. For example, when the user pulls out the paper cassette 30 from the digital multifunction peripheral 10, the paper 34 is stored therein.

  The lift plate 31 is disposed inside the paper cassette 30 and is placed so that a plurality of sheets 34 are stacked thereon. As a result, the paper 34 is stored in the paper cassette 30. Further, a pickup roller 35 is disposed above the lift plate 31, and the paper 34 placed on the lift plate 31 is supplied to the image forming unit 16 one by one by the pickup roller 35. A fixed portion 36 that is a part of the sheet feeding device 23 and is fixed is disposed below the lift plate 31.

  The lift plate 31 is movable in the vertical direction. Here, the up and down direction is the direction indicated by the arrow A in FIG. 2 and the opposite direction, which are the vertically upper side and the vertically lower side. As shown in FIG. 2, the lift plate 31 is stopped at a position where the upper surface of the upper end paper 34 a of the paper 34 placed on the lift plate 31 is in contact with the pickup roller 35. is there. In this case, the position of the upper end paper 34a is fixed. When the user stores the paper 34, the position where the lift plate 31 is stopped is a position where the lower surface of the lift plate 31 is in contact with the fixed portion 36. FIG. 3 shows a state in which the lower surface of the lift plate 31 is in contact with the fixed portion 36. In this case, the position of the bottom sheet 34b is fixed. Here, of the positions where the lift plate 31 is stopped, the position where the upper surface of the upper sheet 34a is brought into contact with the pickup roller 35 is defined as the first position, and the lower surface of the lift plate 31 is brought into contact with the fixed portion 36. This position is the second position. The lift plate 31 is moved to the first position by a motor (not shown) after the paper 34 is stored by the user at the second position.

  The lift plate 31 is provided with a first through hole 31a and a second through hole 31b penetrating in the vertical direction. Details will be described later.

  The first sensor 32 is provided in the vicinity of the pickup roller 35. Then, light is emitted from the upper side of the lift plate 31 toward the upper end paper 34a, and the irradiated light is reflected by the upper end paper 34a, so that it is placed on the lift plate 31 based on the reflected light. Among the printed sheets, the position of the upper end sheet 34a is detected. Here, the first sensor 32 operates as an irradiation unit and a light receiving unit. Further, the first through hole 31 a is provided in a portion of the lift plate 31 corresponding to a position where light is irradiated by the first sensor 32. Here, the first sensor 32 operates as first detection means.

  Further, the second sensor 33 irradiates light from the lower side of the lift plate 31 toward the lower end paper 34 b, thereby positioning the lower end paper 34 b among the papers placed on the lift plate 31. Detect. Further, unlike the first through hole 31a, the second through hole 31b is provided in a portion of the lift plate 31 corresponding to a position where light is irradiated by the second sensor 33. Here, the second sensor 33 operates as second detection means.

  The sensors 32 and 33 are not limited to this, and may be ultrasonic sensors that detect a distance. In this case, the through holes 31a and 31b are provided at portions corresponding to positions where ultrasonic waves are output.

  Here, a case where the number of sheets 34 placed on the lift plate 31 is calculated when the digital multifunction peripheral 10 is operating in the sleep mode will be described. FIG. 4 is a flowchart showing the operation of the control unit 11 when calculating the number of sheets 34 placed on the lift plate 31 when operating in the sleep mode. A description will be given with reference to FIGS.

  First, the digital multi-function peripheral 10 operates in the sleep mode (step S11 in FIG. 4; hereinafter, steps are omitted), and the cassette 30 is pulled out from the digital multi-function peripheral 10 by the user (S12). At this time, the lift plate 31 stops at the second position in order to store the sheet by the user (S13). Then, the user stores the paper 34 and pushes the cassette 30 back to the digital multi-function peripheral 10 (S14).

  Then, since the digital multi-function peripheral 10 is in the sleep mode, the digital multifunction peripheral 10 calculates the number of sheets 34 on the lift plate 31 without moving the lift plate 31 while stopping at the second position.

  Specifically, as shown in FIG. 3, the first sensor 32 is used to detect the position of the uppermost paper 34a among the papers placed on the lift plate 31 (S15). When the position of the top sheet 34a is detected (YES in S15), the number of sheets 34 placed on the lift plate 31 is calculated. For example, in S15, the distance A from the first sensor 32 to the upper end paper 34a is detected as the position of the upper end paper 34a. When the lift plate 31 is stopped at the second position, the position of the lower end paper 34b is fixed, and therefore the distance a from the first sensor 32 to the lower end paper 34b is set in advance to the hard disk 17. The number of sheets 34 is calculated from the difference between the distance A and the distance a (S16). Here, the control unit 11 operates as a number calculating unit.

  When the upper end paper 34a cannot be detected (NO in S15), the light emitted from the first sensor 32 passes through the first through hole 31a as shown in FIG. . The second sensor 33 also passes through the second through hole 31b. As a result, the number of sheets placed on the lift plate 31 is calculated as zero (S17). FIG. 5 is a diagram showing a state in which the paper 34 is not placed.

  Next, a case where the number of sheets placed on the lift plate 31 is calculated when the digital multifunction peripheral 10 is operating in the normal mode will be described. FIG. 6 is a flowchart showing the operation of the control unit 11 when calculating the number of sheets placed on the lift plate 31 when operating in the normal mode. A description will be given with reference to FIGS.

  First, the digital multifunction peripheral 10 operates in the normal mode (S21). At this time, the lift plate 31 is stopped at the first position (S22). Then, the number of sheets 34 on the lift plate 31 is calculated.

  Specifically, as shown in FIG. 2, the second sensor 33 is used to detect the position of the lower end paper 34b among the papers 34 placed on the lift plate 31 (S23). When the position of the bottom sheet 34b is detected (YES in S23), the number of sheets 34 placed on the lift plate 31 is calculated. For example, in S23, the distance B from the second sensor 33 to the lower end paper 34b is detected as the position of the lower end paper 34b. When the lift plate 31 is stopped at the first position, since the position of the upper end paper 34a is fixed, the distance b from the second sensor 33 to the upper end paper 34a is set in advance to the hard disk 17. The number of sheets 34 is calculated from the difference between the distance B and the distance b (S24).

  When the lower end paper 34b cannot be detected (NO in S23), the light emitted from the first sensor 32 passes through the first through hole 31a as shown in FIG. . The second sensor 33 also passes through the second through hole 31b. Thus, the number of sheets placed on the lift plate 31 is calculated as 0 (S25). FIG. 7 is a diagram illustrating a state in which the paper 34 is not placed.

  In this way, the paper feeding device 23 is placed on the placement plate 31 at the position where the movable placement plate 31 is stopped, depending on the detected position of the upper sheet 34a and the position of the lower sheet 34b. The number of printed sheets is calculated. Therefore, when calculating the number of sheets, it is not necessary to drive the motor to move the mounting plate 31. Further, in order to detect the position of the upper sheet 34a from the upper side of the mounting plate 31 and the position of the lower sheet 34b from the lower side of the mounting plate 31, for example, even when the sheets are not aligned. The number of sheets can be calculated appropriately. As a result, power consumption can be reduced and the number of sheets can be calculated appropriately.

  In particular, in the sleep mode, the number of sheets can be calculated without driving the motor, so that power consumption can be further suppressed.

  Further, by providing the lift plate 31 with the first and second through holes 31a and 31b, it can be accurately calculated that the number of sheets is zero.

  Further, the digital multi-function peripheral 10 including such a paper feeding device 23 has the detected position of the upper end paper 34a and the lower end paper 34b at the position where the movable mounting plate 31 is stopped in the paper feeding device 23. The number of sheets placed on the placement plate 31 is calculated based on the position of. Therefore, when calculating the number of sheets, it is not necessary to drive the motor to move the mounting plate 31. Further, in order to detect the position of the upper sheet 34a from the upper side of the mounting plate 31 and the position of the lower sheet 34b from the lower side of the mounting plate 31, for example, even when the sheets are not aligned. The number of sheets can be calculated appropriately. As a result, power consumption can be reduced and the number of sheets can be calculated appropriately.

  In the above embodiment, when calculating the number of sheets in S16, the distance a is previously stored in the hard disk 17 or the like, so that the number of sheets is calculated from the difference between the distance A and the distance a. Although the calculation example has been described, the present invention is not limited thereto, and the number of sheets may be calculated by detecting the distance from the second sensor 33 to the lower end sheet 34b.

  The same applies to S24, and the number of sheets is calculated by detecting the distance from the first sensor 32 to the uppermost sheet 34a without storing the distance b in the hard disk 17 or the like in advance. May be.

  In the above embodiment, the example in which the number of sheets is calculated when the lift plate 31 is stopped at the first position or the second position has been described. However, the present invention is not limited to this. It may be a stopped position other than the first position or the second position.

  In the above-described embodiment, the example in which the number of sheets is calculated as 0 by providing the first through hole 31a and the second through hole 31b in the lift plate 31 has been described. When the plate 31 is a transparent plate, the first through hole 31a and the second through hole 31b may not be provided.

  In the above embodiment, an example in which the first through-hole 31a and the second through-hole 31b are provided is described. However, the present invention is not limited to this, and the first sensor 32 and the second through-hole 31b are provided. One hole corresponding to the light output from the sensor 33 may be provided.

  In the above-described embodiment, the example in which the paper feeding device 23 is controlled by the control unit 11 of the digital multifunction peripheral 10 has been described. It may be configured, and may be controlled by a control unit in the sheet feeding device 23. In this case, the paper feeder supplies the paper to a predetermined location.

  Further, in the above-described embodiment, the example in which the paper feeding device 23 places the paper on the lift plate 31 and the lift plate 31 is movable in the vertical direction has been described, but the present invention is not limited thereto. The lift plate 31 can also be applied to a case where the lift plate 31 is movable in the lateral direction, that is, in a direction perpendicular to the vertical upper side and the vertical lower side. In this case, the sheets are stored in the sheet cassette 30 in the horizontal direction.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

  DESCRIPTION OF SYMBOLS 10 Digital multifunction device, 11 Control part, 12 DRAM, 13 Operation part, 14 Document feeder, 15 Image reading part, 16 Image formation part, 17 Hard disk, 18 FAX communication part, 19 Network IF part, 20 Public line, 21 Network , 22 PC, 23 paper feeder, 30 cassette, 31 lift plate, 31a, 31b through-hole, 32, 33 sensor, 34 paper, 34a top paper, 34b bottom paper, 35 pickup roller, 36 fixing part.

Claims (7)

A paper feeding device that can place paper and has a placement plate that can move in the vertical direction, and supplies the paper to a predetermined location,
A first detection means for detecting the position of the uppermost sheet among the sheets placed on the previous placement plate at a position where the placement plate is stopped and disposed above the previous placement plate;
A second detection means for detecting the position of the lower end paper among the paper placed on the previous placement plate at a position where the placement plate is stopped and disposed on the lower side of the previous placement plate;
The number calculating means for calculating the number of sheets placed on the mounting plate according to the position of the upper end sheet detected by the first detecting means and the position of the lower end sheet detected by the second detecting means. A paper feeding device. The detecting means includes an irradiating means for irradiating the paper placed on the mounting plate with light, and a light receiving means for receiving the reflected light when the light irradiated by the irradiating means is reflected by the paper. The sheet feeding device according to claim 1, further comprising: a sheet position detected based on the reflected light received by the light receiving unit. The sheet feeding device according to claim 2, wherein a through-hole penetrating in a vertical direction is provided in a portion corresponding to a position irradiated with light by the irradiation unit in the mounting plate. Unlike the first through hole, the first through hole is provided in a portion corresponding to a position irradiated with light by the first detection unit, and the second detection unit emits light. The sheet feeding device according to claim 3, further comprising: a second through hole provided in a portion corresponding to a position where the irradiation is performed. Among the papers placed on the placement plate, a pickup roller that contacts the upper surface of the uppermost paper and picks up the paper one by one sequentially,
5. The position according to claim 1, wherein the position where the mounting plate is stopped is a position where the upper surface of the uppermost sheet of the sheets placed on the mounting plate is in contact with the pickup roller. The paper feeder described in 1. On the lower side of the mounting plate, a fixed part is provided,
The paper feeding device according to claim 1, wherein the position where the mounting plate is stopped is a position where the lower surface of the mounting plate is brought into contact with the fixed portion. An image forming apparatus comprising: an image forming unit that forms an image on a paper; and a paper feeding device that supplies the paper to the image forming unit,
The paper feeder is
A paper can be placed and has a placement plate that can move in the vertical direction.
A first detection means for detecting the position of the uppermost sheet among the sheets placed on the previous placement plate at a position where the placement plate is stopped and disposed above the previous placement plate;
A second detection means for detecting the position of the lower end paper among the paper placed on the previous placement plate at a position where the placement plate is stopped and disposed on the lower side of the previous placement plate;
The number calculating means for calculating the number of sheets placed on the mounting plate according to the position of the upper end sheet detected by the first detecting means and the position of the lower end sheet detected by the second detecting means. An image forming apparatus comprising:

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