Patent Grant
10308451
This application is based upon and claims the benefit of priority from the corresponding Japanese Patent Application No. 2017-160900 filed Aug. 24, 2017, the entire contents of which are hereby incorporated by reference.
The present disclosure relates to a sheet feeding device that feeds paper sheets. In addition, the present disclosure relates to an image forming apparatus including the sheet feeding device. In addition, the present disclosure relates to a method for controlling the sheet feeding device.
There are image forming apparatuses such as a multifunction peripheral, a copier, a printer, and a facsimile machine. The image forming apparatus stores paper sheets. For example, paper sheets are housed in a sheet cassette. When performing printing, the paper sheets are fed. The image forming apparatus (sheet feeding device) may perform detection about the paper sheets. There is a known example of a device that detects remaining quantity of paper sheets by using a sensor described below.
Specifically, there is a known sheet feed control device, which makes pressure contact with the top surface of paper sheets stacked on a sheet placing plate so as to feed a paper sheet, identifies stack quantity of paper sheets based on an induced voltage generated by an induction coil when the induction coil and electromagnetic field generation means are disposed at corresponding positions and one of them is disposed to move according to movement of the sheet placing plate, and determines presence or absence of a sheet feed cassette based on a detection signal output from a cassette detection unit.
The image forming apparatus includes the sheet feeding device. The sheet feeding device may include a sheet cassette. A bundle of paper sheets is set in the sheet cassette. To replenish or change paper sheets, the sheet cassette is detachable and attachable. When paper sheets run out, the sheet cassette is pulled out from the image forming apparatus. After paper sheets are replenished, the sheet cassette is inserted into the image forming apparatus.
During a period while the sheet cassette is detached, paper sheets cannot be fed. In other words, during a period while the sheet cassette is not attached, printing cannot be performed. Accordingly, a sensor for detecting whether or not the sheet cassette is attached is usually provided. In addition, if the sheet cassette is insufficiently inserted, sheet jamming may occur. Therefore, a contact-type switch is used as a sensor for detecting an attached or detached state. For example, a part of the contact-type switch contacts with a case of the sheet cassette. Using the contact-type sensor, it can be checked whether or not the sheet cassette is sufficiently inserted.
In addition, the sheet feeding device is equipped with a plurality of sensors other than the attachment/detachment detection sensor. For example, a sensor for detecting a sheet size and a sensor for detecting remaining quantity of paper sheets are disposed. As these sensors, a sensor including an actuator, and a plurality of optical sensors are used. One or more sensors are used for one detection item. There is a problem that an increase in the number of sensors causes an increase in development time and effort and in production cost.
In the known technique described above, one or more sensors are used for detecting remaining quantity of paper sheets. In addition, a cassette detection unit for detecting presence or absence of the sheet feed cassette is disposed separately. There is no description about a try to reduce the number of sensors, and hence the problem described above cannot be solved.
A sheet feeding device according to the present disclosure includes a cassette, a first sensor unit, a first moving mechanism, a storage unit, and a control unit. The cassette includes a sheet placing plate having an upper surface on which paper sheets are set. The cassette is detachable and attachable. The first sensor unit includes a first conductive plate and a first coil circuit board on which a coil pattern is printed. The first coil circuit board is applied with a voltage so that a magnetic field is generated. The first sensor unit outputs a first output value corresponding to a position of the first conductive plate. The first moving mechanism moves the first conductive plate so that a facing area between the first conductive plate and the first coil circuit board is increased or decreased according to remaining quantity of paper sheets in the cassette. The storage unit stores remaining quantity detection data for determining current remaining quantity of paper sheets corresponding to the first output value. The storage unit stores a reference value for determining whether or not the cassette is attached. The control unit recognizes a magnitude of the first output value. The first conductive plate is attached to the cassette. The first coil circuit board is not attached to the cassette but is disposed at a position facing the first conductive plate in a non-contact manner when the cassette is attached. The control unit determines the current remaining quantity of paper sheets based on the magnitude of the first output value and the remaining quantity detection data. The control unit determines whether or not the cassette is attached based on the magnitude of the first output value and the reference value.
Further features and advantages of the present disclosure will become apparent from the description of embodiments given below.
The present disclosure is aimed at enabling a sensor for detecting remaining quantity of paper sheets to also detect whether or not a cassette is attached. An embodiment of the present disclosure is described below with reference to
(Outline of Image Forming Apparatus)
First, with reference to
The control unit 2 is connected to a document feeding unit 4a and an image reading unit 4b in a communicable manner. The document feeding unit 4a feeds a set document (sheet) to a reading position. The image reading unit 4b reads the document fed by the document feeding unit 4a or a document set on a document table (or contact glass, not shown). The image reading unit 4b generates image data of the document. The control unit 2 controls operations of the document feeding unit 4a and the image reading unit 4b.
The control unit 2 is connected to an operation panel 5 in a communicable manner. The operation panel 5 includes a display panel 51, a touch panel 52, and a hardware key 53. For example, the hardware key 53 is a start key. The control unit 2 controls display of the display panel 51. The control unit 2 controls the display panel 51 to display information. The information to be displayed is, for example, a setting screen, a status of the multifunction peripheral 100, or a message. The control unit 2 controls the display panel 51 to display an operation image. The operation image is a software key or button. On the basis of an output of the touch panel 52, the control unit 2 recognizes an operated operation image. In addition, the control unit 2 recognizes the hardware key 53 operated. The control unit 2 controls the display panel 51 to switch to a screen corresponding to the operated operation image or hardware key 53. In addition, the control unit 2 controls the multifunction peripheral 100 to operate according to setting with the operation panel 5.
The multifunction peripheral 100 includes a printing unit 6. The printing unit 6 includes a sheet feeding unit 6a, a conveying unit 6b, an image forming unit 6c, and a fixing unit 6d. The control unit 2 controls the printing unit 6. The printing unit 6 performs sheet feeding, sheet conveying, toner image forming, transferring, and fixing. In other words, the control unit 2 controls operations of the sheet feeding unit 6a, the conveying unit 6b, the image forming unit 6c, and the fixing unit 6d. Specifically, the control unit 2 controls the sheet feeding unit 6a to feed paper sheets one by one. The control unit 2 controls the conveying unit 6b to convey the fed paper sheet to a discharge tray (not shown) via the image forming unit 6c and the fixing unit 6d. The control unit 2 controls the image forming unit 6c to form a toner image to be on the paper sheet conveyed by the conveying unit 6b. The control unit 2 controls to transfer the toner image onto the paper sheet. The control unit 2 controls the fixing unit 6d to fix the toner image transferred onto the paper sheet.
The multifunction peripheral 100 includes a communication unit 23. The communication unit 23 is an interface for communication. The communication unit 23 communicates with a computer 200. The computer 200 is a PC or a server, for example. The communication unit 23 communicates with the computer 200 via a network. The communication unit 23 receives print data from the computer 200. The print data contains image data or the like indicating print content and print setting data. The control unit 2 controls the printing unit 6 to perform printing based on the print data.
(Sheet Feeding Unit 6a)
Next, with reference to
The cassette 61 includes a sheet placing plate 63, a width regulation cursor pair 64 (only one of cursors is shown in
A lifting mechanism 67 is disposed below the downstream end of the sheet placing plate 63. The lifting mechanism 67 moves the sheet placing plate 63 upward. The lifting mechanism 67 includes a lifting motor 67a (see
The width regulation cursor pair 64 can be moved to slide in a direction perpendicular to the conveying direction. Width regulation cursors 64a of the width regulation cursor pair 64 move together with each other. The width regulation cursors 64a contact with the set paper sheets so that the position of the paper sheets is regulated. The rear end regulation cursor 65 can be moved to slide in the conveying direction. The rear end regulation cursor 65 contacts with the set paper sheets. The rear end regulation cursor 65 regulates a rear end position of the paper sheets.
The sheet feeding mechanism 62 includes a sheet feed roller 62a and a handling roller pair 62b. The sheet feed roller 62a is disposed above the downstream end of the sheet placing plate 63. The handling roller pair 62b is disposed on the downstream side of the sheet feed roller 62a in the conveying direction. The handling roller pair 62b prevents double feeding of paper sheets. The upper roller of the handling roller pair 62b rotates to feed a paper sheet in the forward direction. The lower roller rotates to feed a paper sheet in the reverse direction (toward the cassette).
(Sheet Feeding Device 1)
With reference to
The sheet feeding unit 6a includes the cassette 61, the sheet feed roller 62a, the lifting mechanism 67, a sensor unit 7, and a moving mechanism 9. The sensor unit 7 includes a first sensor unit 71, a second sensor unit 72, and a third sensor unit 73. The first sensor unit 71 is a unit for detecting remaining quantity of paper sheets set in the cassette 61 (sheet placing plate 63). In addition, the first sensor unit 71 is also a unit for determining whether or not the cassette 61 is attached. The second sensor unit 72 and the third sensor unit 73 are units for detecting a size of paper sheets set in the sheet feeding unit 6a (cassette 61). Details of the sensor unit 7 are described later.
The rotation shaft of the sheet feed roller 62a is supported by a shaft support member 68. The shaft support member 68 is put on the rotation shaft of the handling roller pair 62b. With the shaft support member 68, the sheet feed roller 62a swings in the up and down direction. Along with moving up and down of the sheet feed roller 62a, the shaft support member 68 swings in the up and down direction. An upper limit sensor S1 is provided to the sheet feeding device 1. The upper limit sensor S1 detects that the sheet feed roller 62a has reached a predetermined upper limit by movement of the sheet placing plate 63.
When the downstream end of the sheet placing plate 63 moves upward, the sheet feed roller 62a contacts with the upper most paper sheet. When the sheet placing plate 63 is further moved upward, a position of the sheet feed roller 62a is also raised. The sheet placing plate 63 raises the sheet feed roller 62a. The upper limit sensor S1 detects that the sheet feed roller 62a has reached the upper limit position. Therefore, when the sheet feed roller 62a is at the upper limit position, the sheet placing plate 63 is also at the upper limit. The upper limit position changes depending on thickness of the bundle of paper sheets set currently.
The upper limit sensor S1 is, for example, a transmission type optical sensor. The upper limit sensor S1 changes its signal output level (high level or low level) depending on whether or not the sheet feed roller 62a is at the upper limit position. The sheet feed roller 62a or the shaft support member 68 is provided with a protrusion 69. When the sheet feed roller 62a reaches the upper limit position, the protrusion 69 blocks an optical path between a light emitting part and a light receiving part of the upper limit sensor S1 (optical sensor). The control unit 2 recognized that the sheet feed roller 62a has reached the upper limit based on the output of the upper limit sensor 51. When recognizing the reaching to the upper limit, the control unit 2 stops the lifting motor 67a.
With reference to
When the cassette 61 is pulled out frontward, the coupling part 67d is separated. In this way, coupling between the lifting motor 67a and the drive shaft 67b is released. In other words, coupling between the coupling part 67d and the drive shaft 67b is released. As a result, the drive transmission path is disconnected. When the cassette 61 is detached (coupling is released), the sheet placing plate 63 is automatically moved downward by gravity action. The lifting mechanism 67 utilizes the gravity action to move the sheet placing plate 63 downward. Finally, the sheet placing plate 63 moves down to a lower limit position. The lifting mechanism 67 moves the sheet placing plate 63 and the lifting member 67c downward to the lower limit position. The sheet placing plate 63 and the lifting member 67c fall flat.
In addition, when the cassette 61 is securely and fully inserted, the drive shaft 67b is inserted into the coupling part 67d. The coupling part 67d makes coupling between the lifting motor 67a and the drive shaft 67b. On the basis of an output value (first output value V1) of the first sensor unit 71, the control unit 2 recognizes that the cassette 61 has been attached. After this recognition, or when starting sheet feeding, the control unit 2 controls the lifting motor 67a to operate. The control unit 2 controls the sheet feed roller 62a and the sheet placing plate 63 to move to the upper limit position. Note that the control unit 2 controls the lifting motor 67a to briefly rotate every feeding of one or more paper sheets. When the paper sheets are consumed so that the sheet feed roller 62a moves down a little, the sheet feed roller 62a is moved again up to the upper limit position.
When sending out the paper sheet, the control unit 2 controls a sheet feeding motor 62c to rotate. In this way, the sheet feed roller 62a and the handling roller pair 62b rotate. The sheet feed roller 62a and the handling roller pair 62b send the paper sheet to the downstream. The conveying unit 6b is provided with a plurality of conveying roller pairs 6br. The conveying roller pairs 6br convey the paper sheet (see
In addition, the sheet feeding unit 6a is provided with a set sensor S2. The set sensor S2 is a sensor for detecting whether or not paper sheets are set (for example, optical sensor). An output level of the set sensor S2 when paper sheets are set is different from that when paper sheets are not set (high level or low level). On the basis of the output of the set sensor S2, the control unit 2 can detect whether or not paper sheets are set in the cassette 61. When there is no paper sheet, the control unit 2 controls the display panel 51 to display run out of paper sheets.
(Sensor Unit 7)
Next, with reference to
When the cassette 61 is attached, the first conductive plate 81 faces the first coil circuit board L1 in a non-contact manner. In addition, the first conductive plate 81 is moved by a first moving mechanism 9a along with upward movement of the sheet placing plate 63. When the first conductive plate 81 moves, a facing area between the first coil circuit board L1 and the first conductive plate 81 is changed. According to a position of the first conductive plate 81, a magnitude of eddy current generated in the first conductive plate 81 or an inductance of the first coil circuit board L1 is changed. As a result, a resonance frequency of the first resonant circuit 71e is changed according to a position of the first conductive plate 81.
The first circuit part 71a includes a first input signal generating circuit 71b, a first frequency detecting circuit 71c, and a first output circuit 71d. The first input signal generating circuit 71b supplies the first resonant circuit 71e (first coil circuit board L1) with current (pulse signal) so that resonance occurs. The first frequency detecting circuit 71c counts a period of a signal waveform of the first resonant circuit 71e. The first frequency detecting circuit 71c detects a resonance frequency of the first resonant circuit 71e. The first output circuit 71d outputs a digital value corresponding to the resonance frequency (period count value) of the first resonant circuit 71e, as the first output value V1. The first sensor unit 71 applies a voltage to the first coil circuit board L1 so as to generate a magnetic field. The first sensor unit 71 outputs the first output value V1 corresponding to a position of the first conductive plate 81. The first output value V1 is input to the control unit 2. The control unit 2 recognizes a magnitude of the first output value V1.
The second sensor unit 72 detects a size in a direction perpendicular to the conveying direction. The second sensor unit 72 includes a second circuit part 72a, a second coil circuit board L2, a second capacitor C2, and a second conductive plate 82. The second capacitor C2 has a predetermined capacitance. The second capacitor C2 and the second coil circuit board L2 are connected in parallel to terminals of the second circuit part 72a. The second coil circuit board L2 and the second capacitor C2 form a second resonant circuit 72e. The second coil circuit board L2 is a circuit board on which a coil pattern P2 is printed (details are described later). The second conductive plate 82 is a plate having electrical conductivity. A metal plate such as a stainless steel plate or an aluminum plate can be used as the second conductive plate 82. The second conductive plate 82 has a width in the moving direction smaller than that in the longitudinal direction of the second coil circuit board L2 (details of movement of the second conductive plate 82 are described later).
When the cassette 61 is attached, the second conductive plate 82 faces the second coil circuit board L2 in a non-contact manner. The second conductive plate 82 is moved by a second moving mechanism 9b in the longitudinal direction of the second coil circuit board L2. The inductance of the second coil circuit board L2 is changed according to a position of the second conductive plate 82. The resonance frequency of the second resonant circuit 72e is changed according to a position of the second conductive plate 82.
The second circuit part 72a includes a second input signal generating circuit 72b, a second frequency detecting circuit 72c, and a second output circuit 72d. The second input signal generating circuit 72b supplies the second resonant circuit 72e (second coil circuit board L2) with current (pulse signal). In this way, the second resonant circuit 72e is resonated. The second frequency detecting circuit 72c counts a period of a signal waveform of the second resonant circuit 72e. The second frequency detecting circuit 72c detects a resonance frequency of the second resonant circuit 72e. The second output circuit 72d outputs a second output value V2. The second output circuit 72d outputs a digital value corresponding to the resonance frequency (period count value) of the second resonant circuit 72e, as the second output value V2. The second sensor unit 72 applies the second coil circuit board L2 with a voltage so that a magnetic field is generated. The second sensor unit 72 outputs the second output value V2 based on the resonance frequency corresponding to a position of the second conductive plate 82. The second output value V2 is input to the control unit 2. The control unit 2 recognizes a magnitude of the second output value V2.
In addition, the third sensor unit 73 detects a size in a direction parallel to the conveying direction. The third sensor unit 73 includes a third circuit part 73a, a third coil circuit board L3, a third capacitor C3, and a third conductive plate 83. The third capacitor C3 has a predetermined capacitance. The third capacitor C3 and the third coil circuit board L3 connected in parallel to terminals of the third circuit part 73a. The third coil circuit board L3 and the third capacitor C3 form a third resonant circuit 73e. The third coil circuit board L3 is a circuit board on which a coil pattern P3 is printed (details are described later). The third conductive plate 83 is also a plate having electrical conductivity. A metal plate such as a stainless steel plate or an aluminum plate can be used as the third conductive plate 83. The third conductive plate 83 has a width in the moving direction smaller than that in the longitudinal direction of the third coil circuit board L3 (details of movement of the third conductive plate 83 are described later).
When the cassette 61 is attached, the third conductive plate 83 faces the third coil circuit board L3 in a non-contact manner. The third conductive plate 83 is moved by a third moving mechanism 9c in the longitudinal direction of the third coil circuit board L3 (details are described later). The inductance of the third coil circuit board L3 is changed according to a position of the third conductive plate 83. The resonance frequency of the third resonant circuit 73e is changed according to a position of the third conductive plate 83.
The third circuit part 73a includes a third input signal generating circuit 73b, a third frequency detecting circuit 73c, and a third output part 73d. The third input signal generating circuit 73b supplies the third resonant circuit 73e (third coil circuit board L3) with current (pulse signal). In this way, the third resonant circuit 73e is resonated. The third frequency detecting circuit 73c counts a period of a signal waveform of the third resonant circuit 73e. The third frequency detecting circuit 73c detects a resonance frequency of the third resonant circuit 73e. The third output part 73d outputs a third output value V3. The third output part 73d outputs a digital value corresponding to the resonance frequency (period count value) of the third resonant circuit 73e, as the third output value V3. The third sensor unit 73 applies the third coil circuit board L3 with a voltage so that a magnetic field is generated. The third sensor unit 73 outputs the third output value V3 corresponding to the resonance frequency according to a position of the third conductive plate 83. The third output value V3 is input to the control unit 2. The control unit 2 recognizes a magnitude of the third output value V3.
(Outline of Detection of Remaining Quantity of Paper Sheets)
Next, with reference to
As illustrated in
The first conductive plate 81 is provided to the cassette 61. The first coil circuit board L1 is disposed outside the cassette 61. As the cassette 61 is pulling out, the first conductive plate 81 is separating from the first coil circuit board L1. When the cassette 61 is attached, the first coil circuit board L1 is disposed at a position facing the first conductive plate 81 in a non-contact manner. In other words, when the cassette 61 is attached, the first coil circuit board L1 and the first conductive plate 81 (rotation plate 10) face each other with a short distance (predetermined distance). The first conductive plate 81 is attached to the rotation plate 10 so that the most acute angle part (the tip part of the triangle or crescent) of the first conductive plate 81 is positioned upward. In
When the drive shaft 67b rotates, the facing area between the first conductive plate 81 and the first coil circuit board L1 is changed.
A winding quantity of the coil pattern P1 facing the first conductive plate 81 is changed according to the position of the first conductive plate 81 (height of the sheet placing plate 63). As illustrated in
A quantity of eddy current in the first conductive plate 81 (magnitude of magnetic force) is changed according to the position of the first conductive plate 81. Strength of magnetic coupling between the first coil circuit board L1 and the first conductive plate 81 is also changed. An inductance (impedance) of the first coil circuit board L1 is also changed. As a result, the first output value V1 of the first circuit part 71a becomes a value corresponding to the position of the first conductive plate 81.
(Flow of Detection of Remaining Quantity of Paper Sheets)
Next, with reference to
The flow of
The control unit 2 controls the first circuit part 71a to operate (Step #12). In this way, resonance occurs in the first resonant circuit 71e. The first circuit part 71a outputs the first output value V1 corresponding to the resonance frequency of the first resonant circuit 71e (corresponding to the remaining quantity of paper sheets, or corresponding to the thickness of set paper sheets) (Step #13).
The control unit 2 recognizes a magnitude of the first output value V1 (Step #14). On the basis of remaining quantity detection data A1 (stored in the storage unit 3) and the first output value V1, the control unit 2 determines the remaining quantity of set paper sheets (Step #15). The remaining quantity detection data A1 is stored in the storage unit 3. The remaining quantity detection data A1 is data for determining current remaining quantity of paper sheets based on the first output value V1.
With reference to
The number of paper sheets in the cassette 61 that is full is 500 for plain paper sheets. This corresponds to the fact that plain paper sheets available in general are wrapped as a unit of 500 sheets. Note that when the cassette 61 is pulled out, the sheet placing plate 63 falls flat. After that, approximately 500 paper sheets are set. A gap is provided between the top surface of the set bundle of paper sheets and the sheet feed roller 62a. This is to prevent the top of the bundle of paper sheets from abutting the sheet feed roller 62a when the cassette 61 is restored. After setting paper sheets to full, it is necessary to move the sheet placing plate 63 upward until the uppermost paper sheet contacts with the sheet feed roller 62a.
The full sheet value is set to a value of a lower limit value plus a reference variation. The lower limit value is the first output value V1 in a state where the sheet placing plate 63 is fallen flat to the lower limit position. The reference variation is determined in advance. The reference variation is a standard variation of the first output value V1 when the sheet feed roller 62a is moved upward to the upper limit position in the state where paper sheets is fully set.
As described above with reference to
The control unit 2 divides an absolute value of a difference between the recognized first output value V1 and the no sheet value by an absolute value of a difference between the no sheet value and the full sheet value. A ratio of the current thickness of the bundle of paper sheets to the thickness of the bundle of full paper sheets is determined. As they are proportional to each other, the remaining quantity detection data A1 can also be a linear function of Z (remaining quantity of paper sheets)=a (gradient)×X (first output value V1)+b (intercept). In this case, the control unit 2 determines the remaining quantity of paper sheets by calculation using the linear function.
(Calculation of Remaining Number of Sheets)
Next, with reference to
First, the flow of
The control unit 2 determines the paper sheet thickness (Step #25). The paper sheet thickness is an absolute value of a difference between the first output value V1 obtained in Step #21 and the first output value V1 obtained in Step #24. In other words, the control unit 2 determines the variation of the first output value V1 corresponding to one paper sheet. Next, the control unit 2 determines the current remaining number of sheets (Step #26). The control unit 2 divides an absolute value of a difference between the current first output value V1 and the no sheet value by the paper sheet thickness. An absolute value of a difference between the no sheet value and the current first output value V1 corresponds to a thickness of the remaining bundle of paper sheets. In addition, the paper sheet thickness corresponds to one paper sheet. In other words, the control unit 2 divides a value that corresponds to a thickness of the remaining bundle of paper sheets by a value that corresponds to one paper sheet. In this way, the remaining number of paper sheets in the cassette 61 is determined.
Note that it is possible to configure the operation panel 5 (touch panel 52 or hardware key 53) to accept an input of the thickness of the set paper sheets. Then, the remaining number of sheets may be determined based on the input thickness of the paper sheets. For example, when a predetermined operation is made, the control unit 2 controls the display panel 51 to display a screen for selecting a paper sheet thickness (paper type) from a plurality of types such as thick paper, normal paper, and thin paper. Then, the touch panel 52 accepts the selection of the paper type. The storage unit 3 stores the variation of the first output value V1 when one sheet is fed, for each paper type. On the basis of the data stored in the storage unit 3, the control unit 2 divides the absolute value of a difference between the current first output value V1 and the no sheet value by the variation of the first output value V1 corresponding to one sheet of the selected paper type. In this way, the current remaining number of sheets is determined. The control unit 2 controls the display panel 51 to display the determined remaining number of sheets (Step #27). In this way, the detection of remaining number of sheets is finished. This flow is finished (END).
(Determination Whether or not Cassette 61 is Attached)
Next, with reference to
During the period while the control unit 2 and the first sensor unit 71 are supplied with power, the control unit 2 periodically checks the first output value V1. Then, the control unit 2 periodically determines whether or not the cassette 61 is attached. The period is appropriately determined. The period may be any period from one second to ten and a few seconds. In addition, the period may be less than one second. The flow of
First, the control unit 2 controls the first sensor unit 71 to operate (Step #31). In other words, the control unit 2 controls the first sensor unit 71 to check the resonance frequency of the first resonant circuit 71e. Then, the control unit 2 recognizes the first output value V1 output from the first sensor unit 71 (Step #32). In addition, the control unit 2 checks whether or not the first output value V1 is smaller than a reference value A2 (Step #33). The reference value A2 is determined in advance. The storage unit 3 stores the reference value A2 in a nonvolatile manner (see
As described above, as the facing area between the first coil circuit board L1 and the first conductive plate 81 is larger, the first output value V1 becomes larger. As the magnetic coupling between the first coil circuit board L1 and the first conductive plate 81 is stronger, the first output value V1 becomes larger. Therefore the first sensor unit 71 outputs the first output value V1 of a larger value as a distance between the first coil circuit board L1 and the first conductive plate 81 is smaller. In addition, the first sensor unit 71 outputs the first output value V1 of a smaller value as the distance between the first coil circuit board L1 and the first conductive plate 81 is larger.
The reference value A2 is determined based on the lower limit value. The lower limit value is the lowest value of the first output value V1 that can be output in the state where the cassette 61 is attached. Note that the lower limit value is not zero. When the cassette 61 is detached, the sheet placing plate 63 moves downward by gravity. Further, the distance between the first coil circuit board L1 and the first conductive plate 81 is increased. Therefore, when the cassette 61 is detached (pulled out), the first output value V1 becomes smaller than the reference value A2.
Further, it is possible that a reference value (first reference value) for detecting that the cassette 61 is detached is different from a reference value (second reference value) for detecting that the cassette 61 is attached (mounted). When the cassette 61 is attached, the first output value V1 may be smaller than the reference value A2 by a slight difference. In order to prevent misdetection that the cassette 61 is not attached, the second reference value may be smaller than the first reference value. In this case, the first reference value and the second reference value are stored in the storage unit 3. When detecting that the cassette 61 is attached, the control unit 2 switches the reference value A2 to be used to the first reference value. When the power is turned on or when detecting that the cassette 61 is not attached, the control unit 2 switches the reference value A2 to be used to the second reference value.
The control unit 2 checks whether or not the first output value V1 is smaller than the reference value A2 (Step #33). When the first output value V1 is larger than or equal to the reference value A2 (No in Step #33), the control unit 2 determines that the cassette 61 is attached (Step #34). Then, the flow returns to Step #31.
On the other hand, when the first output value V1 is smaller than the reference value A2 (Yes in Step #33), the control unit 2 determines that the cassette 61 is not attached (Step #35). When determining that the cassette 61 is not attached, the control unit 2 controls the display panel 51 to display a message informing that the cassette 61 is not attached (Step #36).
Further, the control unit 2 controls the sheet feeding device 1 and the printing unit 6 to be in a print job inhibiting mode (Step #37). When switching to the print job inhibiting mode in a state where the print job is not being executed, the control unit 2 does not allow the sheet feeding device 1 and the printing unit 6 to operate. In other words, the control unit 2 does not allow to perform sheet feeding and image forming. When switching to the print job inhibiting mode in a state where the print job is being executed, the control unit 2 controls the printing unit 6 to print only on the paper sheet that is already fed. Then, the control unit 2 does not allow sheet feeding of a new paper sheet and toner image forming by transferring onto a new paper sheet by the printing unit 6. Note that in a case where a plurality of sheet feeding units 6a are disposed and the other sheet feeding unit 6a can feed a paper sheet, the control unit 2 may not control the sheet feeding device 1 to be in the print job inhibiting mode.
Then, the control unit 2 checks again whether or not the first output value V1 is smaller than the reference value A2 (Step #38). When the first output value V1 is smaller than the reference value A2 (No in Step #38), the flow returns to Step #36. The control unit 2 maintains the determination that the cassette 61 is not attached. On the other hand, when the first output value V1 is larger than or equal to the reference value A2 (No in Step #38), the control unit 2 determines that the cassette 61 is attached (Step #39). Then, the control unit 2 cancels the print job inhibiting mode (Step #310). In other words, the control unit 2 restores the sheet feeding device 1 and the image forming apparatus to a print job executable mode. Then, the flow returns to Step #31.
Note that when using the first sensor unit 71, whose first output value V1 becomes larger as the magnetic coupling between the first coil circuit board L1 and the first conductive plate 81 is weaker, the reference value A2 is determined based on the upper limit value. In this case, the upper limit value is the maximum value of the first output value V1 that can be output in the state where the cassette 61 is attached. Note that the upper limit value is smaller than the maximum value that the first sensor unit 71 can output. When the cassette 61 is detached (pulled out), the first output value V1 becomes larger than the reference value A2. In this case, when the first output value V1 is larger than or equal to reference value A2, the control unit 2 determines that the cassette 61 is not attached. In addition, when the first output value V1 is smaller than the reference value A2, the control unit 2 determines that the cassette 61 is attached.
When detecting that the cassette 61 is attached, the control unit 2 may automatically update the full sheet value. When the control unit 2 determines that the cassette 61 is attached (No in Step #38, and Step #39), the control unit 2 recognizes a magnitude of the first output value V1. The control unit 2 determines a new value of the full sheet value based on the recognized first output value V1. Then, the control unit 2 controls the storage unit 3 to update the full sheet value to the new value. Further, the control unit 2 may automatically update the no sheet value to be associated with the full sheet value. When the control unit 2 recognizes that there are no paper sheets based on the output of the set sensor S2, the control unit 2 controls the sheet placing plate 63 (sheet feed roller 62a) to move upward to the upper limit position. Then, the control unit 2 recognizes a magnitude of the first output value V1. The control unit 2 controls the storage unit 3 to update the no sheet value to the recognized value. In this way, accurate remaining quantity can be detected all the time.
(Adjustment of Reference Value A2)
Next, with reference to
Therefore, in the sheet feeding device 1, the reference value A2 can be adjusted. The flow of
Next, the control unit 2 controls the display panel 51 to display a message requesting to attach (mount) the cassette 61 (Step #42). The control unit 2 may control the operation panel 5 to display a detachment confirmation button. Further, when the detachment confirmation button is operated, the control unit 2 may control the display panel 51 to display an attachment request message.
The control unit 2 recognizes the first output value V1 (Step #43). The control unit 2 may control the operation panel 5 to display an attachment confirmation button. Further, when the attachment confirmation button is operated, the control unit 2 may recognize the first output value V1. The recognized first output value V1 is the lower limit value. Further, when the cassette 61 is attached, the control unit 2 recognizes the first output value V1 (lower limit value) before the sheet placing plate 63 moves upward. A new value of the reference value A2 is determined based on the recognized first output value V1. The control unit 2 controls the storage unit 3 to update the reference value A2 to the new value (Step #44).
(Outline of Sheet Size Detection)
Next, with reference to
On the second coil circuit board L2 and the third coil circuit board L3, a length in the longitudinal direction of the winding becomes gradually shorter toward the inside winding. For example, when n represents a length in the longitudinal direction of the most inside winding, a length in the longitudinal direction of a winding is (number of turns)×n. On the other hand, an interval between windings in the short direction is set as small as possible. The coil pattern P2 is formed so that the winding quantity facing the second conductive plate 82 varies according to a position of the second conductive plate 82. The coil pattern P3 is also formed so that the winding quantity facing the third conductive plate 83 varies according to a position of the third conductive plate 83.
The winding quantity facing the second conductive plate 82 varies according to a position of the second conductive plate 82. In other words, density of the winding facing the second conductive plate 82 varies according to a position of the second conductive plate 82. In the example illustrated in
The winding quantity facing the third conductive plate 83 varies according to a position of the third conductive plate 83. In other words, density of the winding facing the third conductive plate 83 varies according to a position of the third conductive plate 83. In the example illustrated in
(Second Moving Mechanism 9b)
Next, with reference to
As illustrated in
A linkage member 64b is disposed below each of the width regulation cursors 64a (below the partition plate 610). The linkage member 64b has a longitudinal direction that is perpendicular to the conveying direction. The linkage member 64b is a member like a plate, a rod, or a column. The linkage member 64b is attached perpendicularly to each of the width regulation cursors 64a viewed from above. The linkage member 64b is positioned in the lower layer 612 of the cassette 61. One linkage members 64b and the other linkage member 64b are disposed at different positions in the conveying direction.
A rotation member 64c is disposed at the center position between the inner surfaces of the width regulation cursors 64a. The rotation member 64c is disposed between the linkage members 64b. The rotation member 64c is also disposed in the lower layer 612. The rotation member 64c has a rotation axis perpendicular to a paper sheet placing surface (partition plate 610). The outer circumferential surface of the rotation member 64c is provided with teeth. In addition, each of the linkage members 64b is also provided with a teethed surface 64d. The teethed surface 64d is provided to one of sides of the linkage member 64b on the rotation member 64c side. The teethed surface 64d of each linkage members 64b is disposed so as to engage with the teeth of the rotation member 64c.
The teethed surfaces 64d of the linkage members 64b engage with the rotation member 64c. Therefore, when one of the width regulation cursors 64a is moved, the other width regulation cursor 64a is also moved (in linkage therewith). Specifically, when one of the width regulation cursors 64a is moved inward, the other width regulation cursor 64a is also moved inward. When one of the width regulation cursors 64a is moved outward, the other width regulation cursor 64a is also moved outward. The linkage movement of the width regulation cursors 64a enables the center of paper sheets in the direction perpendicular to the conveying direction to coincide with the center of the sheet conveying path in the width direction (center sheet feeding) even if any size of paper sheets are set.
The second coil circuit board L2 is disposed outside of the cassette 61. The longitudinal direction of the second coil circuit board L2 is parallel to the conveying direction. The second moving mechanism 9b is disposed in the lower layer 612 of the cassette 61. The second moving mechanism 9b moves the second conductive plate 82 in the longitudinal direction of the second coil circuit board L2 according to positions of the cursors. The second moving mechanism 9b includes a first gear 91, a first rack 92, a second gear 93, and a second rack 94. The first rack 92 is connected to one of the width regulation cursors 64a. The first rack 92 is attached to the width regulation cursor 64a. The longitudinal direction of the first rack 92 is perpendicular to the conveying direction. The first rack 92 moves in the direction perpendicular to the conveying direction along with the movement of the width regulation cursor 64a.
Teeth of the first rack 92 are engaged with the first gear 91. In addition, the first gear 91 and the second gear 93 are engaged with each other. Teeth of the second rack 94 are engaged with the second gear 93. In addition, the second rack 94 faces the second coil circuit board L2. The longitudinal direction of the second rack 94 is parallel to the conveying direction. The second rack 94 moves in the conveying direction along with rotation of the second gear 93. Therefore, the longitudinal direction of the second rack 94 and a movement direction thereof are parallel to the longitudinal direction of the second coil circuit board L2.
The second conductive plate 82 is attached to the second rack 94. As illustrated in
The second conductive plate 82 is attached to the end of the second rack 94 on the upstream side in the conveying direction. The second moving mechanism 9b (the first rack 92, the first gear 91, the second gear 93, and the second rack 94) converts the movement of the width regulation cursor 64a in the direction perpendicular to the conveying direction to the movement in a direction parallel to the conveying direction. According to a position of the width regulation cursor 64a, the second moving mechanism 9b moves the second conductive plate 82 in the longitudinal direction of the second coil circuit board L2. In this way, the winding quantity facing the second conductive plate 82 varies.
The lower part of
(Third Moving Mechanism 9c)
Next, with reference to
The rear end regulation cursor 65 moves to slide in the direction parallel to the conveying direction. The inner surface of the rear end regulation cursor 65 contacts with the rear end of the set paper sheets (edge on the upstream side in the conveying direction). As illustrated in
The third moving mechanism 9c includes a rod member 95. One end of the rod member 95 is connected (attached) to the rear end regulation cursor 65. The longitudinal direction of the rod member 95 is perpendicular to the conveying direction. The other end of the rod member 95 faces the third coil circuit board L3. The third conductive plate 83 is attached to the other end of the rod member 95. A part of the third conductive plate 83 (surface facing the third coil circuit board L3) is exposed to outside of the case of the cassette 61. In order to expose the third conductive plate 83, the case of the cassette 61 is provided with a groove. In this way, the third conductive plate 83 and the third coil circuit board L3 can be close to each other. Note that it is possible to adopt a structure in which the groove is not provided so that the third conductive plate 83 is not exposed to outside of the case. The third moving mechanism 9c moves the rod member 95 according to a position of the rear end regulation cursor 65. The third conductive plate 83 moves in the longitudinal direction of the third coil circuit board L3. In this way, the winding quantity facing the third conductive plate 83 varies.
The lower part of
(Flow of Sheet Size Detection)
Next, with reference to
First, the control unit 2 operates the second circuit part 72a and the third circuit part 73a (Step #51). The second circuit part 72a outputs the second output value V2 corresponding to the resonance frequency (Step #52). The third circuit part 73a outputs the third output value V3 corresponding to the resonance frequency (Step #53). The control unit 2 recognizes magnitudes of the second output value V2 and the third output value V3 (Step #54). The control unit 2 recognizes a size of the set paper sheets in the direction perpendicular to the conveying direction based on the first sheet size data D1 (stored in the storage unit 3) and the second output value V2 (Step #55).
With reference to
In addition, the control unit 2 recognizes a size of the set paper sheets in the conveying direction based on the second sheet size data D2 (stored in the storage unit 3) and the third output value V3 (Step #56). With Step #56, the detection of the set sheet size is finished. Then, this flow is finished (END). With reference to
In addition, as described above with reference to
In this way, the sheet feeding device 1 according to the embodiment includes the cassette 61, the first sensor unit 71, the first moving mechanism 9a, the storage unit 3, and the control unit 2. The cassette 61 includes the sheet placing plate 63 having the upper surface on which paper sheets are set. The cassette 61 is detachable and attachable. The first sensor unit 71 includes the first conductive plate 81 and the first coil circuit board L1 on which the coil pattern P1 is printed. The first sensor unit 71 applies a voltage to the first coil circuit board L1 so that a magnetic field is generated. The first sensor unit 71 outputs the first output value V1 corresponding to a position of the first conductive plate 81. The first moving mechanism 9a moves the first conductive plate 81 so that a facing area between the first coil circuit board L1 and the first conductive plate 81 is increased or decreased according to a remaining quantity of paper sheets in the cassette 61. The storage unit 3 stores the remaining quantity detection data A1 for determining a current remaining quantity of paper sheets corresponding to the first output value V1. The storage unit 3 stores the reference value A2 for determining whether or not the cassette 61 is attached. The control unit 2 recognizes a magnitude of the first output value V1. The first conductive plate 81 is disposed in the cassette 61. The first coil circuit board L1 is not disposed in the cassette 61. The first coil circuit board L1 is disposed at a position facing the first conductive plate 81 in a non-contact manner when the cassette 61 is attached. The control unit 2 determines the current remaining quantity of paper sheets based on the magnitude of the first output value V1 and the remaining quantity detection data A1. The control unit 2 determines whether or not the cassette 61 is attached based on the magnitude of the first output value V1 and the reference value A2.
In this way, the sensor for detecting the remaining quantity of paper sheets can also detect whether the cassette 61 is attached or detached. A dedicated sensor for detecting whether or not the cassette 61 is attached, which is disposed in a conventional structure, can be eliminated. Therefore, cost in manufacturing the sheet feeding device 1, and time and effort for developing the same can be reduced. In addition, when the cassette 61 is inserted strongly (vigorously), a dedicated sensor for detecting the attachment may be damaged. However, the first coil circuit board L1 and the first conductive plate 81 do not contact with each other. Even if the cassette 61 is inserted strongly, the sheet feeding device 1 according to the present disclosure does not cause a breakdown of the sensor. Therefore it is possible to provide the sheet feeding device 1 that is resistant to breakdown.
In addition, the first sensor unit 71 outputs the first output value V1 having a larger value as the distance between the first coil circuit board L1 and the first conductive plate 81 is smaller, and as the facing area between the first coil circuit board L1 and the first conductive plate 81 is larger. The control unit 2 determines that the cassette 61 is not attached when the first output value V1 is smaller than the reference value A2. The control unit 2 determines that the cassette 61 is attached when the first output value V1 is larger than or equal to the reference value A2. In this way, it is possible to correctly determine (detect) whether or not the cassette 61 is attached based on a magnitude relationship of the first output value V1.
In addition, the sheet feeding device 1 includes the sheet feed roller 62a, and the lifting mechanism 67. The sheet feed roller 62a is disposed above the sheet placing plate 63. The sheet feed roller 62a sends out paper sheets set on the sheet placing plate 63. The lifting mechanism 67 moves the sheet placing plate 63 upward and downward. When the cassette 61 is attached, the lifting mechanism 67 moves the sheet placing plate 63 upward until the sheet feed roller 62a contacts with the paper sheets on the sheet placing plate 63. The first moving mechanism 9a moves the first conductive plate 81 so that the facing area between the first coil circuit board L1 and the first conductive plate 81 is increased or decreased according to a height of the sheet placing plate 63. The lifting mechanism 67 sets the sheet placing plate 63 at the lower limit position when the cassette 61 is detached. The reference value A2 is determined based on the first output value V1 when the sheet placing plate 63 is at the lower limit position. In this way, when the cassette 61 is detached, the sheet placing plate 63 can be set at the lower limit position. An initial position of the sheet placing plate 63 when the cassette 61 is attached can be set at the lower limit position. The reference value A2 can be set based on the first output value V1 corresponding to an initial position of the sheet placing plate 63 when the cassette 61 is attached. Attachment or detachment of the cassette 61 can be correctly determined.
In addition, the lifting mechanism 67 includes the drive shaft 67b, the lifting member 67c, and the lifting motor 67a. The lifting member 67c is attached to the drive shaft 67b. The lifting member 67c lifts the sheet placing plate 63 to move upward. The lifting motor 67a rotates the drive shaft 67b. The first moving mechanism 9a includes the rotation plate 10. The rotation plate 10 is fixed to the drive shaft 67b. The rotation plate 10 changes its rotation angle along with a rotation angle of the drive shaft 67b. The first conductive plate 81 has a substantially triangular shape and is attached to the rotation plate 10. The first coil circuit board L1 is disposed at a position facing the rotation plate 10 when the cassette 61 is attached. As the sheet placing plate 63 moves upward, the rotation plate 10 moves the first conductive plate 81 to be close to the center of the first coil circuit board L1, viewing the first coil circuit board L1 and the first conductive plate 81 from front, and hence the facing area between the first coil circuit board L1 and the first conductive plate 81 is increased. In this way, the facing area between the first coil circuit board L1 and the first conductive plate 81 can be increased in proportion to an upward moving amount of the sheet placing plate 63. The facing area between the first coil circuit board L1 and the first conductive plate 81 can be decreased in proportion to a downward moving amount of the sheet placing plate 63. Therefore the first output value V1 can be changed according to a height of the sheet placing plate 63 (remaining quantity of paper sheets).
In addition, the cassette 61 includes the width regulation cursors 64a, the second moving mechanism 9b, and the second sensor unit 72. The width regulation cursors 64a regulate a position of the set paper sheets. The width regulation cursors 64a can move to slide in the direction perpendicular to the conveying direction. The second sensor unit 72 includes the second conductive plate 82 and the second coil circuit board L2. The coil pattern P2 is printed on the second coil circuit board L2. The second sensor unit 72 applies a voltage to the second coil circuit board L2 so that a magnetic field is generated. The second sensor unit 72 outputs the second output value V2 corresponding to a position of the second conductive plate 82. The second conductive plate 82 is disposed in the cassette 61. The second coil circuit board L2 is not disposed in the cassette 61. The second coil circuit board L2 is disposed at a position facing the second conductive plate 82 in a non-contact manner when the cassette 61 is attached. A movement range of the second conductive plate 82 is smaller than a length of the second coil circuit board L2 in the longitudinal direction. The second moving mechanism 9b moves the second conductive plate 82 in the longitudinal direction of the second coil circuit board L2 according to a position of the width regulation cursor 64a. The storage unit 3 stores the first sheet size data D1 for determining a size of paper sheets in the direction perpendicular to the conveying direction corresponding to a magnitude of the second output value V2. When determining that the cassette 61 is attached, the control unit 2 recognizes a size of the set paper sheets in the direction perpendicular to the conveying direction based on the magnitude of the second output value V2 and the first sheet size data D1.
In this way, by supplying current to the second coil circuit board L2, eddy current can be generated in the second conductive plate 82. An inductance of the second coil circuit board L2 has a value corresponding to a degree of magnetic coupling between the second coil circuit board L2 and the second conductive plate 82. A sheet size in the direction perpendicular to the conveying direction can be determined based on the second output value V2 having much higher definition (higher resolution) compared with a conventional method (a method using an optical sensor or a contact-type switch). Therefore a size of set paper sheets can be detected correctly with high accuracy. When using non-standard size paper sheets, it is not necessary to set a correct length of the paper sheets in the direction perpendicular to the conveying direction. Further, as the second coil circuit board L2 and the second conductive plate 82 do not contact with each other, there is no abrasion between them. Therefore there is little aging deterioration.
In addition, the cassette 61 includes the rear end regulation cursor 65, the third moving mechanism 9c, and the third sensor unit 73. The rear end regulation cursor 65 regulates a position of the set paper sheets. The rear end regulation cursor 65 can move to slide in the conveying direction. The third sensor unit 73 includes the third conductive plate 83 and the third coil circuit board L3. The coil pattern P3 is printed on the third coil circuit board L3. The third sensor unit 73 applies a voltage to the third coil circuit board L3 so that a magnetic field is generated. The third sensor unit 73 outputs the third output value V3 corresponding to a position of the third conductive plate 83. The third conductive plate 83 is disposed in the cassette 61. The third coil circuit board L3 is not disposed in the cassette 61. The third coil circuit board L3 is disposed at a position facing the third conductive plate 83 in a non-contact manner when the cassette 61 is attached. The third conductive plate 83 has a movement range smaller than a length of the third coil circuit board L3 in the longitudinal direction. The third moving mechanism 9c moves the third conductive plate 83 in the longitudinal direction of the third coil circuit board L3 according to a position of the rear end regulation cursor 65. The storage unit 3 stores the second sheet size data D2 for determining a paper sheet size in the conveying direction corresponding to a magnitude of the third output value V3. When determining that the cassette 61 is attached, the control unit 2 recognizes a size of the set paper sheets in the conveying direction based on a magnitude of the third output value V3 and the second sheet size data D2.
In this way, by supplying the third coil circuit board L3 with current, eddy current can be generated in the third conductive plate 83. An inductance of the third coil circuit board L3 has a value corresponding to a degree of magnetic coupling between the third coil circuit board L3 and the third conductive plate 83. A sheet size in the conveying direction can be determined based on the output value having much higher definition (higher resolution) compared with a conventional method (a method using an optical sensor or a contact-type switch). A size of set paper sheets can be correctly detected with high accuracy. When using non-standard size paper sheets, it is not necessary to set a sheet size. Further, the third coil circuit board L3 and the third conductive plate 83 also do not contact with each other, and hence there is no abrasion. Therefore there is little aging deterioration.
In addition, the image forming apparatus (multifunction peripheral 100) includes the sheet feeding device 1. As it includes the sheet feeding device 1 described above, cost in manufacturing the image forming apparatus, and time and effort for developing the same can be reduced. In addition, it is possible to provide the image forming apparatus including the sheet feeding device 1 that is resistant to breakdown. Although the embodiment of the present disclosure is described above, the present disclosure is not limited to this and can be variously modified for implementation without deviating from the spirit of the disclosure.
| Number | Date | Country | Kind |
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| 2017-160900 | Aug 2017 | JP | national |
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| 5572630 | Azuma | Nov 1996 | A |
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| 7-61646 | Mar 1995 | JP |
| Number | Date | Country | |
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| 20190062079 A1 | Feb 2019 | US |
