JP2008114998A - Sheet feeder, and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet feeder capable of inexpensively detecting whether a sheet-feeding cassette has been detached/attached in a power-off state. <P>SOLUTION: This sheet feeder X includes a control part 120 determining presence of attachment/detachment of the sheet-feeding cassette 100 in a power-off state of the sheet feeder X based on a first detection result detected by a recording sheet sensor 106 in turning on power every time the power of the sheet feeder X is turned on, a second detection result memorized by a storage part 121 in turning off power, and a third detection result detected by the recording sheet sensor 106 when a recording sheet mounting plate 101 is moved, by a motor 104, a shaft 103 and a moving plate 102 after turning on the power, to a position where the uppermost layer of the recording sheets mounted on its upper surface reaches a predetermined sheet-feeding position, or the recording sheet mounting plate 101 without mounting the recording sheets thereon is moved to the uppermost part within a movable range. <P>COPYRIGHT: (C)2008,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 and an image forming apparatus having a function of determining whether a sheet feeding cassette detachable from the apparatus main body is attached or detached when the power is turned off.

In the conventional paper feeding device, the attachment / detachment of the paper feeding cassette is detected by a paper feeding cassette detection sensor or the like in order to grasp the insertion / extraction of the recording paper stored in the paper feeding cassette. Of course, the detection by the paper feed cassette detection sensor can be executed only when power is supplied. Therefore, in such a conventional paper feeding device, it has not been possible to determine whether the paper feeding cassette is attached or detached when the power supply of the paper feeding device is turned off.
In order to grasp the attachment and detachment of the paper feed cassette when the power is turned off as described above, Patent Document 1 is provided with a storage tray means which can be attached to and detached from the apparatus body, and an electromagnetic solenoid. An apparatus is described in which the storage tray means is restricted from being attached and detached. In this device, when the power is turned off, the lock mechanism that can manually remove the restriction on the attachment and detachment of the storage tray means without driving the electromagnetic solenoid, and whether or not the lock mechanism is manually operated when the power is turned off. And the storage means for storing the information, it is possible to grasp whether the storage tray means is attached or detached in the power-off state.
JP-A-11-339102

However, the apparatus described in Patent Document 1 cannot be applied to the image forming apparatus not provided with the lock mechanism as described above, and there is a problem that it is expensive to provide the lock mechanism.
Accordingly, the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a sheet feeding device that can achieve at a low cost grasp of whether or not a sheet feeding cassette is attached / detached in a power-off state. is there.

A recording paper stacking plate that is provided in a paper feed cassette that is detachably attached to the main body of the paper feeding device, and a lowermost part of a range in which the recording paper stacking plate can be moved when the paper feeding cassette is attached or detached And a recording paper detecting device for detecting whether or not the uppermost layer of the recording paper loaded on the recording paper stacking plate is at a predetermined paper feeding position. In order to determine whether or not the paper cassette is attached or detached when the power is turned off, an expensive mechanism must be provided.
In the present invention, the recording paper stacking plate is moved to the movable uppermost portion when the power supply of the paper feeding device is turned off, and the recording paper detection result storage means for storing the detection result detected by the recording paper detection means at that time The first detection result detected by the recording paper detection means when the power supply is turned on and the second detection result stored by the recording paper detection result storage means each time the power is turned on. After the power is turned on, the recording paper stacking plate is moved by the moving means to a position where the uppermost layer of the recording paper placed on the upper surface reaches the paper feeding position or no recording paper is placed. Based on the third detection result detected by the recording paper detecting means when the recording paper stacking plate is moved to the uppermost part of the movable range, the above-mentioned power supply device in the power-off state is based on the third detection result. Whether to insert or remove the paper cassette And it includes a paper feed cassette attachment determination means for determining, a.
As described above, when the paper feeding cassette is attached or detached, the recording paper stacking plate is moved to the lowest position in order to avoid interference. Therefore, when the paper feed cassette is attached or detached, the recording paper stacking plate is at the lowermost position. Therefore, even if the recording paper is stacked on the recording paper stacking plate, the recording paper detecting means removes the recording paper. Not detected. Using this fact, it is determined whether the paper feed cassette is attached or detached.
As a result, it is possible to provide a paper feeding device that can grasp at a low cost whether or not the paper feeding cassette is attached or detached when the power is turned off.
In particular, the paper feed cassette attachment / detachment determining means each time the power supply of the paper feed device is turned on, either the first detection result, the second detection result, or the third detection result, Based on both, it is conceivable to determine whether or not the paper feeding cassette is attached or detached when the power supply of the paper feeding device is turned off.
The paper feed cassette attachment / detachment determining means each time the power supply of the paper feed device is turned on, the first detection result, the second detection result, the third detection result, or both Based on the above, as a specific example of determining whether or not the paper cassette is attached / detached when the power supply of the paper feeder is turned off, if the first detection result is present, Therefore, it may be determined that the paper feed cassette is not attached or detached.
This is because when the first detection result is present, the recording paper stacking plate is not at the lowermost position, and the uppermost layer of the recording paper stacked on the recording paper stacking plate is at the paper feeding position. It can be determined that there is no attachment / detachment.
Further, when the first detection result is not present and the second detection result is present, the paper feed cassette attachment / detachment determining means may determine that the paper feed cassette is attached / detached. .
When the power was turned off, the recording paper stacking plate was not at the bottom, and the uppermost layer of recording paper loaded on the recording paper stacking plate was at the paper feed position. On the other hand, the absence of the first detection result after power-on may mean that the recording paper stacking plate is at the lowest position, or no recording paper is loaded on the recording paper stacking plate. Since the recording paper is not pulled out without moving the recording paper stacking plate to the bottom when the power is turned off, the recording paper stacking plate is at the bottom. Therefore, it can be determined that the paper feed cassette has been attached or detached.
When the second detection result and the first detection result are not present and the third detection result is present, the paper feed cassette attachment / detachment determining means determines that the paper feed cassette is attached / detached. It is possible to do.
This is because when the power is turned off, the recording paper stacking plate is positioned at the uppermost position and no recording paper is stacked on the recording paper stacking plate. When the uppermost layer of the recording paper loaded on the loading plate is moved to the position where it reaches the paper feeding position, the recording paper is detected by the recording paper detecting means. This is because it is considered that the recording paper has been supplied.
And a recording paper stacking plate detecting means for detecting whether or not the recording paper stacking plate is at the top of the movable range of the recording paper stacking plate on which no recording paper is placed. When the recording paper stacking plate is detected by the recording paper stacking plate detecting means when the power is turned on and the recording paper stacking plate is detected when the power is turned on, If the recording paper stacking plate is not detected by the recording paper stacking plate detecting means when the power is turned on, the paper feeding cassette mounting / dismounting determining means can determine that the paper feeding cassette is attached / detached. Conceivable.
By using the detection result of the recording paper stacking plate detection means, it is possible to determine a case where determination cannot be made only with the detection result of the recording paper detection means. For example, when no recording paper is loaded on the recording paper stacking plate of the paper feeding cassette when the power is turned off, the paper feeding cassette is not attached or detached, or the paper feeding is not performed without replenishing the recording paper. It can be determined whether only the cassette has been attached or detached.

  It is possible to provide a sheet feeding device that can achieve low-cost grasping of whether or not a sheet feeding cassette is attached / detached in a power-off state.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that the present invention can be understood. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.
FIG. 1 is a block diagram of a control system of the image forming apparatus Y to which the paper feeding device X according to the embodiment of the present invention is mounted. FIG. 2 is a schematic diagram of the paper feeding device X according to the embodiment of the present invention. FIG. 3 is a flowchart for explaining an example of the procedure of the paper feed cassette attachment / detachment determination process by the control unit 120 of the paper feeder X.

A schematic configuration and movement of the image forming apparatus Y to which the paper feeding apparatus X according to the present embodiment is mounted will be described.
As shown in FIG. 1, the image forming apparatus Y is roughly classified based on an image reading unit 10 that reads a document placed on a document table and image data of the document read by the image reading unit 10. An image forming unit 20 that forms (transfers) a toner image on the recording paper, a paper feeding device X that supplies the recording paper to the image forming unit 20, and a recording paper on which the toner image is formed by the image forming unit 20 A fixing unit 30 for heating and fixing a toner image, an operation input unit 3 for performing various operations such as an image reading start operation, a display unit 2 for displaying various information, a control unit 1 for comprehensively controlling these, and the like It is configured with.

Next, an image forming process executed by the image forming apparatus Y will be briefly described.
When an input operation is performed by the start key of the operation input unit 3 or the like, an image of the document placed on the document table is read by the image reading unit 10, and the read document image light is transmitted from a CCD sensor or the like. After being converted into an electrical image information signal (digital image data) by a photoelectric converter (not shown), predetermined image processing is performed and input to an exposure unit (not shown). Thereafter, a laser beam according to the image data after image processing is emitted from the exposure unit to the surface of the photosensitive drum.
The image forming unit 20 includes the photosensitive drum, and a charging unit, a cleaning unit, and a charge eliminating unit around the photosensitive drum. In the vicinity thereof, a developing unit and a transfer unit facing the photosensitive drum are provided. Is arranged.
Subsequently, an electrostatic latent image is written on the surface of the photosensitive drum charged by the charging unit. The photosensitive drum is rotated in a predetermined direction, and toner carried on the developing roller is electrostatically charged on the surface of the photosensitive drum 6 at a developing position in contact with a developing roller (not shown) provided in the developing unit. The toner image is formed by shifting to the latent image.
The photosensitive drum is continuously rotated, and the toner image formed on the photosensitive drum is transferred to the recording paper conveyed by the paper feeding device X by the transfer unit. The paper feeding operation of the paper feeding device X will be described later. The cleaning unit is disposed downstream of the transfer unit in the rotation direction of the photosensitive drum, and toner and other deposits remaining on the surface of the photosensitive drum are removed. The static elimination unit is provided downstream of the cleaning unit in the rotation direction of the photosensitive drum, and the potential remaining on the photosensitive drum is removed.
The recording paper on which the image has been formed (transferred) is conveyed to the fixing unit 30.
The toner image transferred to the recording paper is heated by the fixing unit 30 and fixed on the recording paper.
Thereafter, the recording paper is conveyed to a discharge roller (not shown) and discharged outside the image forming apparatus Y.

Next, the paper feeding device X will be described.
As shown in FIG. 1, the control system of the paper feeding device X according to the present embodiment has a moving plate 102 that moves a recording paper stacking plate 101 in a paper feeding cassette 100 detachably attached to the main body of the paper feeding device X up and down. A motor 104 for driving the shaft 103, a recording paper stacking plate sensor 105, a recording paper sensor 106, a cassette sensor 107, a pickup roller 108, a paper feeding roller 109, a separation roller 110, and an intermediate conveyance roller 111. , A registration roller 112, a storage unit 121, and a control unit 120 for comprehensively controlling them.
As shown in FIGS. 1 and 2, the paper feed cassette 100 includes a recording paper stacking plate 101 on which recording paper is stacked. The recording paper stacking plate 101 is formed with an opening 101-1 for optically detecting the presence or absence of recording paper.
FIG. 2A is a diagram in the case where the recording paper stacking plate 101 on which the recording paper is placed is at the lowest part of the movable range, that is, in a horizontal state.
The shaft 103 is long in the attachment / detachment direction of the paper feed cassette 100, is provided in the paper feed device X body, and is rotated by the motor 104.
One end of the moving plate 102 is fixed to the shaft 103. Therefore, when the paper feed cassette 100 is mounted on the main body of the paper feed device X, the moving plate 102 is rotationally displaced about the shaft 103 as the shaft 103 is driven by the motor 104. . Then, the recording paper stacking plate 101 is pushed up, and the recording paper stacked on the recording paper stacking plate 101 is brought into contact with the pickup roller 108. When there is no recording paper, the recording paper stacking plate 101 itself is brought into contact with the pickup roller 108. The position of the recording paper stacking plate 101 at this time is the uppermost position in the movable range of the recording paper stacking plate 101 and is a position detected by a recording paper stacking plate sensor 105 described later. This is detected by, for example, a limit switch or a photo sensor.
The pickup roller 108 feeds the contact recording sheet and conveys it to the paper feed roller 109. The position of the recording paper when in contact with the pickup roller 108 is referred to as a paper feeding position.
In FIG. 2B, the recording paper stacking plate 101 on which the recording paper is placed is pushed up by the rotation of the shaft 103 and the moving plate 102 driven by the motor 104, and is placed on the recording paper stacking plate 101. FIG. 6 is a diagram illustrating a state in which the uppermost layer of the placed recording paper is at the paper feeding position.
The paper feeding cassette 100 can be attached to and detached from the paper feeding device X body, and can be pulled out (removed) in the front direction in FIG. If the uppermost recording paper is in contact with the pickup roller 108 when the paper feeding cassette 100 is attached or detached, the uppermost recording paper may be damaged. The moving plate 102 is moved in the direction of the arrow P1 in FIG. 2B without being driven by the motor 104, so that the lowermost part (see FIG. 2 (a)). With respect to such a structure, the shaft 103 is not driven by the motor 104 when the protrusion provided at the lower front surface of the sheet cassette 100 is pushed down by the member provided at the end of the shaft 103. A known mechanical configuration is adopted in which the moving plate 102 provided at the other end of the shaft 103 is pushed down and pushed down.
Here, a well-known mechanical configuration for moving the recording paper stacking plate 101 to the lowest part of the movable range without driving the motor 104 when the paper feeding cassette 100 is attached or detached is a moving means. It corresponds to an example.
The cassette sensor 107 detects whether or not the paper feed cassette 100 is mounted on the paper feed device X body. Usually composed of photo sensors, limit switches, etc.
The recording paper stacking plate sensor 105 detects whether or not the recording paper stacking plate 101 is at the top of the movable range as described above.
When the recording paper stacking plate sensor 105 detects the recording paper stacking plate 101, the driving of the motor 104 is stopped. As a result, the rotation of the shaft 103 stops, and the moving plate 102 and the recording paper stacking plate 101 also stop.
The recording paper stacking plate sensor 105 corresponds to an example of a recording paper stacking plate detection unit.
The recording paper sensor 106 detects whether or not the uppermost layer of the recording paper loaded on the recording paper stacking plate 101 is at the paper feed position (position in contact with the pickup roller 108 as described above). The recording paper sensor 106 is, for example, a reflective photosensor. If the recording paper is stacked on the recording paper stacking plate 101 and the uppermost layer of the recording paper is at the paper feeding position, the light reflected by the recording paper placed on the recording paper stacking plate 101 is a sensor. The light is received by the light receiving unit and it is determined that there is recording paper. If no recording paper is stacked on the recording paper stacking plate 101, light is not received through the opening 101-1 formed in the recording paper stacking plate 101, so it is determined that there is no recording paper. If there is a recording sheet on the recording sheet stacking plate 101 but the uppermost recording sheet is not in the sheet feeding position (below the sheet feeding position), the recording sheet sensor 106 detects the detection light. Because no signal can be received, a signal indicating no recording paper is output. When the recording paper stacking plate 101 is at the lowest position, the recording paper sensor 106 outputs a signal indicating no recording paper because the recording paper sensor 106 does not reach the paper feeding position even when the maximum amount of recording paper is placed. Thereby, the presence or absence of the recording paper at the paper feeding position is detected.
Here, the recording paper sensor 106 corresponds to an example of a recording paper detection unit.
When the recording paper is detected by the recording paper sensor 106, the driving of the motor 104 is stopped. As a result, the rotation of the shaft 103 stops, and the moving plate 102 and the recording paper stacking plate 101 also stop.
The recording paper stacking plate sensor 105 detects that the recording paper stacking plate 101 is in contact with the pickup roller 108 when there is no recording paper on the recording paper stacking plate 101. When the detection result of the recording paper sensor 106 is present, the detection result of the recording paper stacking plate sensor 105 is absent.
The separation roller 110 separates the recording sheet fed by the sheet feeding roller 109 and feeds only the uppermost recording sheet, and the intermediate conveyance roller 111 conveys the recording sheet conveyed by the separation roller 110. The roller, the registration roller 112 is a roller for conveying the recording paper conveyed from the intermediate conveying roller 111 to the image forming unit 20.

When an instruction to turn off the power supply device X is given, for example, by pressing the power button of the operation input unit 3 of the image forming apparatus Y, the recording paper sensor 106 and the recording paper stacking plate sensor 105 If neither of the detection results is present, the motor 120 is driven by the control unit 120, the shaft 103 is rotated, and the moving plate 102 is rotated upward, whereby the recording paper stacking plate 101 is rotated. However, the uppermost layer of the recording paper placed on the upper surface is moved to a position where it reaches the paper feeding position, or the recording paper stacking plate 101 on which the recording paper is not placed is movable. Moved to the top. Then, the detection result of the recording paper sensor 106 after the recording paper stacking plate 101 is moved is stored in the storage unit 121 by the control unit 120. Thereafter, the power supply of the paper feeding device X is turned off.
Here, the storage unit 121 corresponds to an example of a recording paper detection result storage unit.
The detection result of the recording paper sensor 106 stored in the storage unit 121 corresponds to an example of a second detection result.
In the present embodiment, the storage unit 121 is provided in the sheet feeding device X. However, the storage unit 121 may be replaced with a storage unit (not illustrated) provided in the image forming apparatus Y or may be used in combination. It doesn't matter.

Next, the paper feeding operation of the paper feeding device X will be briefly described.
When the control unit 1 issues a paper feed instruction, the detection results of the recording paper sensor 106 and the recording paper stacking plate sensor 105 are confirmed. If neither of the detection results is present, the motor 104 is driven. The shaft 103 is rotated by driving the motor 104, and the movable plate 102 is rotated. As a result, the recording paper stacking plate 101 is moved upward.
When the recording paper is detected by the recording paper sensor 106, the motor 104 is stopped and the recording paper stacking plate 101 is also stopped. Subsequently, when the pickup roller 108 rotates, the uppermost recording paper of the recording paper stacked on the recording paper stacking plate 101 is sent out and conveyed to the paper supply roller 109. The recording paper conveyed to the paper feed roller 109 is separated by the separation roller 110 and conveyed to the image forming unit 20 by the intermediate conveyance roller 111 and the registration roller 112.
When the recording paper stacking plate 101 is fully raised, if there is a detection result of the recording paper stacking plate sensor 105, the control unit 1 displays on the display unit 2 that there is no recording paper. The
In this paper feeding position, when the power is turned off, the recording paper stacking plate 101 is first moved to the uppermost movable position before the actual cutting.

By the way, in a conventional paper feeding device that restricts attachment / detachment of a sheet cassette by driving an electromagnetic solenoid or the like when energized, the restriction on attachment / detachment of the sheet cassette can be manually canceled when the power is turned off, without driving the electromagnetic solenoid. If there is no storage mechanism for storing whether or not the lock mechanism is manually operated when the power is turned off, and whether or not the paper cassette is attached or detached when the power is turned off I couldn't.
In the present embodiment, the paper feeding device X that achieves low-cost grasping of whether or not the paper feeding cassette 100 is attached or detached when the power feeding device X is turned off without newly providing an expensive mechanism such as the lock mechanism is provided. provide.
Details are described below.

表１において，Ａ列は，当該給紙装置Ｘの電源切断時（上記記録紙積載板１０１が移動可能な最上位置に移動）の上記記録紙センサ１０６による検知結果である。Ｂ列は，電源切断時の上記記録紙積載板１０１の位置であり，「上」は上記記録紙積載板１０１が移動可能な範囲の最上部（上記記録紙積載板１０１の上面に載置された記録紙の最上層が上記給紙位置に達する位置，或いは上記記録紙積載板１０１自体が上記ピックアップローラ１０８に当接する位置）であり，「下」は移動可能な範囲のうちの最上部ではない下方（最下部，もしくは最上部と最下部との間）である。但し，これは検知結果ではなく，想定上の位置である。Ｃ列は電源投入直後の上記記録紙センサ１０６による記録紙有無の検知結果である。記録紙ありは，前記の通り理論上記録紙が給紙位置にあることを示している。Ｄ列は，電源投入直後に上記記録紙センサ１０６による検知が行われた後の動作であり，上記記録紙積載板１０１を上昇させるか，何も行わないかのどちらかである。Ｅ列は，上記Ｄ列の動作後の上記記録紙センサ１０６による検知結果である。Ｆ列は，上記制御部１２０による，当該給紙装置Ｘの電源切断状態での給紙カセット１００の着脱の有無の判断結果であり，「○」は電源切断状態に給紙カセット１００の着脱が行われたとの判断結果，「×」は電源切断状態に給紙カセット１００の着脱は行われていないとの判断結果である。
このうち，番号１，２，５，６，７，８，９，１３，１４，１５，１６は理論上，ありえない状態である（太線で囲んで示されている部分）。
表１の番号１，２の場合は，上記給紙装置Ｘの電源切断時は上記記録紙積載板１０１が最上部にあり，記録紙がなかった（即ち，記録紙積載板がピックアップローラに当たる位置にあった）のに，電源投入後は上記記録紙積載板１０１が給紙位置にあり，記録紙が検知されたことを示しているが，このようなことはありえない。なぜなら，記録紙を補給するには，上記給紙カセット１００を着脱しなければならず，上記給紙カセット１００の着脱を行えば，前述の，上記給紙カセット１００が着脱される時に上記モータ１０４の駆動によらずに上記記録紙積載板１０１を移動可能な範囲のうちの最下部に移動させる周知の構造（移動手段）により，上記記録紙積載板１０１は最下部に位置するから記録紙が検知されることはありえないからである。
表１の番号９の場合は，上記給紙装置Ｘの電源切断時は上記記録紙積載板１０１が給紙位置にあり，（記録紙センサが記録紙ありを検出しているから）電源投入後も上記記録紙積載板１０１は給紙位置にあるので，上記給紙カセット１００の着脱がなかったことはあきらかである。従って，その後，上記記録紙積載板１０１を移動させて上記記録紙センサ１０６の検知結果がなしになる場合を考えなくてもよい。
表１の番号５，６，７，８，１３，１４，１５，１６の場合は，既に述べたように，当該給紙装置Ｘの電源切断時には，上記モータ１０４，上記軸１０３，上記移動板１０２により，上記記録紙積載板１０１が移動可能な範囲のうちの最上部に移動されるので，電源切断時にＢ列の記録紙積載板１０１の位置が「下」であることはないので，考えなくてもよい部分である。 First, there are 16 cases as shown in the following table depending on the detection result of the recording paper sensor 106 before and after the power supply of the paper feeding device X is turned off, the position of the recording paper stacking plate 101, and the like.

In Table 1, row A is a detection result by the recording paper sensor 106 when the power supply of the paper feeding apparatus X is turned off (the recording paper stacking plate 101 is moved to the uppermost movable position). Row B is the position of the recording paper stacking plate 101 when the power is turned off, and “upper” is the uppermost part of the range in which the recording paper stacking plate 101 is movable (it is placed on the upper surface of the recording paper stacking plate 101). (The position where the uppermost layer of the recording paper reaches the paper feeding position, or the position where the recording paper stacking plate 101 itself contacts the pickup roller 108), and “lower” is the uppermost part of the movable range. There is no downward (bottom or between top and bottom). However, this is not a detection result but an assumed position. Column C is the detection result of the presence or absence of recording paper by the recording paper sensor 106 immediately after the power is turned on. The presence of recording paper theoretically indicates that the recording paper is in the paper feed position as described above. The row D is an operation after detection by the recording paper sensor 106 immediately after the power is turned on, and either the recording paper stacking plate 101 is raised or nothing is performed. The E row is a detection result by the recording paper sensor 106 after the operation of the D row. Row F is a result of determination by the control unit 120 as to whether or not the paper feeding cassette 100 is attached / detached when the paper feeding device X is in a power-off state, and “◯” indicates that the paper feeding cassette 100 is attached / detached in a power-off state. As a result of the determination that it has been performed, “×” is a determination result that the sheet feeding cassette 100 has not been attached or detached in the power-off state.
Of these, the numbers 1, 2, 5, 6, 7, 8, 9, 13, 14, 15, and 16 are impossible in theory (portions surrounded by thick lines).
In the case of numbers 1 and 2 in Table 1, when the power supply of the paper feeding device X is turned off, the recording paper stacking plate 101 is at the top and there is no recording paper (that is, the position where the recording paper stacking plate hits the pickup roller). However, after the power is turned on, the recording paper stacking plate 101 is in the paper feeding position, indicating that the recording paper has been detected, but this is not possible. This is because, in order to replenish the recording paper, the paper feed cassette 100 must be attached / detached. If the paper feed cassette 100 is attached / detached, the motor 104 is used when the paper feed cassette 100 is attached / detached. The recording paper stacking plate 101 is positioned at the lowermost position by a known structure (moving means) that moves the recording paper stacking plate 101 to the lowermost part of the movable range without depending on the driving of the recording paper. This is because it cannot be detected.
In the case of No. 9 in Table 1, when the power supply of the paper feeding device X is turned off, the recording paper stacking plate 101 is in the paper feeding position, and after the power is turned on (because the recording paper sensor detects the presence of recording paper). However, since the recording paper stacking plate 101 is at the paper feeding position, it is obvious that the paper feeding cassette 100 was not attached or detached. Therefore, it is not necessary to consider the case where the recording paper loading plate 101 is moved thereafter and the detection result of the recording paper sensor 106 becomes none.
In the case of numbers 5, 6, 7, 8, 13, 14, 15, and 16 in Table 1, as described above, when the power supply of the paper feeding device X is turned off, the motor 104, the shaft 103, and the moving plate 102, the recording paper stacking plate 101 is moved to the top of the movable range. Therefore, the position of the recording paper stacking plate 101 in the B row is not “down” when the power is turned off. This is an unnecessary part.

Next, the procedure of the paper feed cassette attachment / detachment determination process executed by the control unit 120 of the paper feed device X after the power supply of the paper feed device X is turned off and turned on will be described using the flowchart of FIG. In the case of Table 1 (numbers 3, 4, 10, 11, and 12), how the determination is made will also be described.
As described above, when the paper feed cassette 100 is attached or detached, if the uppermost recording paper is in contact with the pickup roller 108, the uppermost recording paper may be damaged. The recording paper stacking plate 101 is moved to the lowest position without using electric parts such as the motor 104. Therefore, when the paper feed cassette 100 is attached or detached with the power off, the recording paper stacking plate 101 is at the lowest position, so that the recording paper is loaded even if the recording paper is stacked on the recording paper stacking plate 101. The sensor 106 does not detect the recording paper. Using this fact, it is determined whether or not the paper feed cassette 100 is attached or detached.
In the figure, S10, S20.
Step S10 is a procedure for waiting for the power supply of the paper feeding device X to be turned on.
When the power of the paper feeding device X is turned on, the recording paper sensor 106 detects the presence or absence of the recording paper at the paper feeding position (step S20), and the process proceeds to step S30.
Here, the detection result detected by the recording paper sensor 106 when the power is turned on in step S20 corresponds to an example of the first detection result.
In step S30, the control unit 120 determines whether or not a recording sheet is detected by the recording sheet sensor 106 in step S20. If the recording paper sensor 106 determines that no recording paper has been detected (Yes in step S30; numbers 3, 4, 11, and 12 in Table 1), the process proceeds to step S40.
If it is determined in step S30 that the recording paper is detected by the recording paper sensor 106 (in the case of number 10 in Table 1) by the control unit 120 (No in step S30), the process ends. To do. This is because the result of detection by the recording paper sensor 106 after the power is turned on means that the recording paper stacking plate 101 is in a position where the uppermost layer of the recording paper placed on the upper surface reaches the paper feeding position. That is, since the recording paper stacking plate 101 is not at the lowermost part, it can be determined that the paper feeding cassette 100 has not been attached or detached.

In step S40, it is determined whether or not the detection result of the recording paper sensor 106 stored in the storage unit 121 when the power is turned off is no recording paper. If the detection result of the recording paper sensor 106 stored in the storage unit 121 when the power is turned off is that there is no recording paper (Yes in step S40; in the case of numbers 3 and 4 in Table 1), the processing is step. The process proceeds to S50. If the detection result of the recording paper sensor 106 stored in the storage unit 121 at the time of power-off is the presence of recording paper (No side in step S40; in case of numbers 11 and 12 in Table 1), step S80 Thus, it is determined that the paper feed cassette 100 has been attached or detached while the power is off. This is because, when the power is turned off, the recording paper stacking plate 101 is in a position where the uppermost layer of the recording paper placed on the upper surface thereof reaches the paper feeding position. This is because it can be determined that the paper cassette 100 has been attached and detached and the recording paper stacking plate 101 has moved to the lowest position or that all of the recording paper has been removed. .
In step S50 (in the case of numbers 3 and 4 in Table 1), the control unit 120 drives the motor 104, the shaft 103 rotates, the moving plate 102 rotates, and the recording paper. The stacking plate 101 is moved to a position where the uppermost layer of the recording paper placed on the upper surface reaches the paper feeding position, or the recording paper stacking plate 101 on which no recording paper is placed is movable. Is moved to the top of the list, and the process proceeds to step S60.

In step S60, the recording paper sensor 106 detects whether there is a recording paper at the paper feed position, and the process proceeds to step S70.
Here, the detection result detected by the recording paper sensor 106 in step S60 corresponds to an example of a third detection result.
In step S70, the control unit 120 determines whether or not the recording paper is detected by the recording paper sensor 106 in step S60. If it is determined that the recording paper is detected by the recording paper sensor 106 (Yes in step S70; number 4 in Table 1), the process proceeds to step S80.
In step S80, the control unit 120 determines that the paper cassette 100 has been attached and detached, and the process ends. This is because the recording paper is not placed on the recording paper stacking plate 101 when the power is turned off, and the recording paper is not detected after the power is turned on (because the recording paper stacking plate 101 is at the bottom) Therefore, after the power is turned on, the recording paper stacking plate 101 is moved to a position where the uppermost layer of the recording paper placed on the upper surface reaches the paper feeding position. When the recording paper loaded on the recording paper stacking plate 101 is detected, the recording paper stacking plate 101 is at the bottom when the power is turned on, and the recording paper is placed thereon. This is because it is considered that the sheet feeding cassette 100 was attached and detached and the recording paper was replenished in the power-off state.
If the recording paper sensor 106 determines that no recording paper has been detected (No side of step S70; step S90), it indicates that no recording paper has been placed after the power is turned on. The control unit 120 determines that nothing has been operated during power-off, and the process ends.

As a result, it is possible to provide the sheet feeding device X that can achieve low-cost grasping of whether or not the sheet feeding cassette 100 is attached / detached in a power-off state.
Here, each time the paper feeding device X is turned on (step S10), the first detection result (steps S20 and S30), the second detection result (step S40), and the third Based on one or both of the detection results (steps S60 and S70), the control unit 120 that determines whether or not the paper feeding cassette 100 is attached or detached when the power supply of the paper feeding device X is turned off is This corresponds to an example of a paper cassette attachment / detachment determination means.
By using this determination result, whether or not the paper cassette 100 is attached / detached in a power-off state is displayed on the display unit 2 of the image forming apparatus Y, so that the user can You may be prompted to confirm the insertion and removal of the recording paper.

上記記録紙センサ１０６の検知結果が記録紙なしの場合に上記記録紙積載板センサ１０５の検知結果が記録紙積載板あり，なしの場合が考えられるので，番号３−１，７−１，１１−１の行を追加した。例えば，電源切断時の上記記録紙センサ１０６の検知結果が記録紙なし，電源投入直後の上記記録紙センサ１０６の検知結果が記録紙なし，動作後の上記記録紙センサ１０６の検知結果が記録紙なし（表２の番号３，３−１）の場合に，電源投入直後の上記記録紙積載板センサ１０５の検知結果をも用いると，上記記録紙積載板１０５は電源切断時，電源投入直後ともに最上部にあり，上記給紙カセット１００の着脱が行われていないと判断される場合（表２の番号３）と，電源切断状態で記録紙の補給はなくただ上記給紙カセット１００の着脱を行っただけの場合と，を区別して判断することができる。
なぜなら，電源切断時は上記記録紙積載板１０１上に記録紙が載置されておらず，電源投入後に記録紙が検出されない（上記記録紙積載板１０１上に記録紙がなく最下部にあるためか，上記記録紙積載板１０１上に記録紙がなく最上部にあるかのいずれか）ので，電源投入後に上記記録紙積載板センサ１０５により上記記録紙積載板１０１が検知されたということは，電源投入時に上記記録紙積載板１０１が最上部にあり，その上に記録紙がない状態であるから，電源切断状態で，上記給紙カセット１００の着脱が行われていないと考えられるからである。
一方，電源投入後に上記記録紙積載板センサ１０５により上記記録紙積載板１０１なしという信号が出力されたということは，上記記録紙積載板１０１は最下部にあるので，電源切断状態で，上記給紙カセット１００の着脱が行われたと考えられる。そして，上記記録紙積載板１０１が上記モータ１０４，上記軸１０３，上記移動板１０２により最上部に移動された後，上記記録紙センサ１０６により記録紙がないと検知信号が出力されたということは，電源切断状態で，上記給紙カセット１００の着脱を行ったものの，上記記録紙積載板１０１に記録紙を載置していないと考えられるからである。 If the detection result of the recording paper sensor 106 is used together with the detection result of the recording paper sensor 106, it is possible to determine a case where the determination cannot be made only by the detection result of the recording paper sensor 106.
Table 2 is obtained by adding the detection result of the recording paper stacking plate sensor 105 immediately after the power is turned on to Table 1.

When the detection result of the recording paper sensor 106 is no recording paper, the detection result of the recording paper stacking plate sensor 105 is considered to be the presence or absence of the recording paper stacking plate. Added a -1 line. For example, the detection result of the recording paper sensor 106 when the power is turned off is no recording paper, the detection result of the recording paper sensor 106 immediately after the power is turned on is no recording paper, and the detection result of the recording paper sensor 106 after the operation is the recording paper In the case of none (numbers 3 and 3-1 in Table 2), if the detection result of the recording paper stacking plate sensor 105 immediately after the power is turned on is used, the recording paper stacking plate 105 is both turned off and immediately after the power is turned on. When it is determined that the paper cassette 100 at the top is not attached or detached (No. 3 in Table 2), the recording paper is not replenished in the power-off state, and the paper cassette 100 is simply attached and detached. It can be judged by distinguishing from the case of just doing it.
This is because the recording paper is not placed on the recording paper stacking plate 101 when the power is turned off, and no recording paper is detected after the power is turned on (because there is no recording paper on the recording paper stacking plate 101 and is at the bottom). The recording paper stacking plate 101 is detected by the recording paper stacking plate sensor 105 after the power is turned on. This is because, when the power is turned on, the recording paper stacking plate 101 is at the top and there is no recording paper on the top, so it is considered that the paper feeding cassette 100 is not attached or detached in the power-off state. .
On the other hand, the fact that the recording paper stacking plate sensor 105 outputs a signal indicating that the recording paper stacking plate 101 is absent after the power is turned on indicates that the recording paper stacking plate 101 is at the lowermost position, so It is considered that the paper cassette 100 has been attached and detached. Then, after the recording paper stacking plate 101 is moved to the top by the motor 104, the shaft 103, and the moving plate 102, a detection signal is output when there is no recording paper by the recording paper sensor 106. This is because it is considered that the recording paper is not placed on the recording paper stacking plate 101 although the paper feeding cassette 100 is attached and detached in the power-off state.

2 is a block diagram of a control system of an image forming apparatus Y to which a paper feeding device X according to an embodiment of the present invention is mounted. FIG. 1 is a schematic cross-sectional view illustrating a schematic configuration of a paper feeding device X according to an embodiment of the present invention. 7 is a flowchart for explaining an example of a procedure of paper feed cassette attachment / detachment determination processing by the control unit 120 of the paper feed device X.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,120 ... Control part 2 ... Display part 3 ... Operation input part 10 ... Image reading part 20 ... Image forming part 30 ... Fixing part 100 ... Paper feed cassette 101 ... Recording paper stacking plate 102 ... Moving plate 103 ... Shaft 104 ... Motor 105 ... Recording paper stacking plate sensor 106 ... Recording paper sensor 107 ... Cassette sensor 108 ... Pickup roller 109 ... Paper feed roller 110 ... Separation roller 111 ... Intermediate conveyance roller 112 ... Registration roller 121 ... Storage section

Claims (7)

A recording paper stacking plate that is provided in a paper feed cassette that is detachably attached to the main body of the paper feeding device, and a lowermost part of a range in which the recording paper stacking plate can be moved when the paper feeding cassette is attached or detached And a recording paper detecting means for detecting whether or not the uppermost layer of the recording paper loaded on the recording paper stacking plate is at a predetermined paper feeding position. And
A recording paper detection result storage means for storing the detection result detected by the recording paper detection means at the time when the recording paper stacking plate is moved to the movable uppermost portion when the power supply of the paper feeding device is turned off;
A first detection result detected by the recording paper detection means when the power is turned on, and a second detection result stored by the recording paper detection result storage means; After the power is turned on, the recording paper stacking plate is moved to a position where the uppermost layer of the recording paper placed on the upper surface thereof reaches the paper feeding position by the moving means, or the recording paper on which no recording paper is placed Based on the third detection result detected by the recording paper detection means when the stacking plate is moved to the top of the movable range, the paper supply in the power-off state of the paper supply device Paper feed cassette attachment / detachment determination means for determining whether the cassette is attached or detached;
A sheet feeding device comprising:   The paper feed cassette attachment / detachment determining means, whenever the power supply of the paper feed device is turned on, either the first detection result, the second detection result, the third detection result, or both, The paper feeding device according to claim 1, wherein whether or not the paper feeding cassette is attached or detached when the power of the paper feeding device is turned off is determined based on.   3. The paper feeding device according to claim 2, wherein when the first detection result is present, the paper feeding cassette attachment / detachment judging means judges that the paper feeding cassette is not attached / detached.   3. The paper feed cassette attachment / detachment judging means judges that the paper feed cassette is attached / detached when the first detection result is not present and the second detection result is present. The paper feeder described in 1.   When the second detection result and the first detection result are not present and the third detection result is present, the paper feed cassette attachment / detachment determining means determines that the paper feed cassette is attached / detached. The paper feeding device according to claim 2. A recording paper stacking plate detecting means for detecting whether or not the recording paper stacking plate is at the top of a movable range of the recording paper stacking plate on which the recording paper is not placed;
When the second detection result and the first detection result are not present, and the recording paper stacking plate is detected by the recording paper stacking plate detection means when the power is turned on, the paper feed cassette attachment / detachment determination means When it is determined that the paper cassette is not attached / detached, and the recording paper stacking plate detecting means is not detected by the recording paper stacking plate detecting means when the power is turned on, the paper feed cassette attaching / detaching judging means judges that the paper cassette is attached / detached. The paper feeding device according to claim 2, wherein   An image forming apparatus comprising the paper feeding device according to claim 1.

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