JP2014125286A - Sheet-residual-quantity detection device and image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet-residual-quantity detection device and an image formation apparatus capable of reducing sheet-residual-quantity detection errors due to minute vibration.SOLUTION: A sheet-residual-quantity detection device includes: a rotational member 20 on which light transmittable transparent regions 20A and nontransparent regions 20B that do not transmit light are alternately arranged in a circumferential direction; a light-receiving unit 50B that includes light-receiving elements arranged to be opposed to the rotational member 20 at a predetermined angle formed between an array direction of the light-receiving elements and a radial direction of the rotational member 20, and outputs different light-receiving level values depending on the light-receiving elements that receive light; and a light-output unit 50A for outputting light to the respective light-receiving elements. A count control unit 12 adds a count value on the basis of predetermined reference information and a change in the light-receiving level value obtained by the light-receiving unit 50B, and a residual quantity detection unit 13 detects a sheet residual quantity using the obtained count value.

Description

  The present invention relates to a remaining paper amount detection apparatus and an image forming apparatus.

  Conventionally, there is a paper remaining amount detection device that detects the remaining amount of paper (see, for example, Patent Document 1).

  In the paper remaining amount detection device described in Patent Document 1, an actuator provided with a plurality of slits is rotated in conjunction with the lifting of the cassette lifting plate. The remaining paper amount detection device detects each slit using a sensor to determine the amount of rotation of the actuator, and detects the remaining amount of paper using the correlation between the amount of rotation of the actuator and the remaining amount of paper. .

  By the way, in the paper remaining amount detecting device, when each slit passes through a position opposite to the sensor, light passing through each slit is detected, and the remaining amount of paper may be detected using the detection result.

  In such a sheet remaining amount detecting device, the amount of lifting of the cassette lifting plate increases as the remaining sheet amount decreases, and each slit of the actuator sequentially passes through the facing position of the sensor in the course of the increase. At that time, as shown in FIG. 14A, pulses with a constant pulse width are sequentially obtained by the sensor.

  However, in the state where the edge portion of the slit exists at the position facing the sensor, when a slight vibration that vibrates with a slight amplitude occurs, the sensor turns on and off at a shorter interval than when the normal actuator rotates. From FIG. 14B, pulses having a pulse width smaller than that in the normal state are sequentially obtained as shown by an ellipse in FIG.

  Even if a pulse with a pulse width different from that in the normal state is obtained in this way, the remaining amount detection device adds a count value, which causes an error in detecting the remaining amount of paper using the count value. End up.

  As a countermeasure against such fine vibration, for example, it is conceivable to count up only when the output time of the detection signal from the sensor is a certain time or more.

Japanese Patent Laid-Open No. 2002-60090

  However, the actuator may slightly vibrate slowly. In this case, it is conceivable that the output time of the detection signal from the sensor exceeds the set time as in the part surrounded by an ellipse in FIG. In this case, even if the count-up is performed only when the output time of the detection signal from the sensor is equal to or longer than the set time, an error in detecting the remaining amount of paper occurs.

  SUMMARY An advantage of some aspects of the invention is that it provides a remaining paper amount detection device and an image forming apparatus that can reduce an error in detecting the remaining amount of paper due to slight vibration. To do.

  A remaining paper amount detection device according to an aspect of the present invention includes a paper storage unit that stores paper, a tray that is provided to place the paper and is movable in the vertical direction inside the paper storage unit, A motor for rotating the tray in a reference rotation direction set in advance so that the uppermost sheet placed on the tray is positioned at a predetermined paper feed position; and A plate-like rotating member that rotates in conjunction with the rotation, and a transmission region that transmits light and a non-transmission region that does not transmit light are alternately arranged along the rotation direction of the rotation member. A rotating member and a plurality of light receiving elements are arranged in a line, and each light receiving element and the rotating member have a predetermined angle between the arrangement direction of the light receiving elements and the radial direction of the rotating member. Level value output with and facing each other A level value output unit that outputs a different light receiving level value depending on the received light receiving element, and the light receiving element that is opposed to the light receiving element across the rotating member, and transmits light toward the light receiving element. A change in the received light level value to be output by the level value output unit when the light output unit to output and the transmission region pass through a position corresponding to the light output unit in a direction corresponding to the reference rotation direction. A storage unit that stores information to be expressed as reference information, a counter, and a count control unit that adds a count value in the counter based on the reference information and a change in the received light level value obtained by the level value output unit And a remaining amount detecting unit that detects the remaining amount of the sheet using the count value obtained by the counter.

  According to this configuration, the light output unit is disposed to face the level value output unit with the rotating member interposed therebetween. In the level value output unit, a plurality of light receiving elements are arranged in a line, and each light receiving element is arranged to face the rotating member at a predetermined angle with the radial direction of the rotating member. The level value output unit outputs a different light reception level value depending on the light receiving element that has received light among the light receiving elements.

  In the process of rotating the rotating member, that is, in the process of passing the transmission region through the position opposed to the light output unit, the light receiving element that receives light changes in the level value output unit. Since the level value output unit outputs different light reception level values depending on the received light receiving element, the light reception level value output from the level value output unit changes in the process where the transmission region passes through the position opposed to the light output unit. To do.

  When the count control unit passes the change in the received light level value output from the level value output unit and the transmission region facing the light output unit in a direction corresponding to a predetermined reference rotation direction. The count value in the counter is added based on the reference information indicating the change in the received light level value to be output from the level value output unit.

  Here, the change represented by the reference information is a change when the rotation member rotates in the reference rotation direction that is the rotation direction of the rotation member when raising the tray. Therefore, the count control unit adds the count value based on the change in the light reception level value output from the level value output unit and the change in the light reception level value when the rotating member rotates in the reference rotation direction.

  As described above, since the count value is added when the rotating member rotates in the reference rotation direction, when the remaining amount is detected using the count value, it is possible to reduce the detection error of the remaining amount of paper due to slight vibration. it can.

  In the above configuration, the count control unit determines the rotation direction of the rotating member based on the change in the received light level value obtained by the level value output unit and the reference information, and the determined rotation direction is When the rotation direction is the reference direction, it is preferable that the count value in the counter is added.

  According to this configuration, since the count value in the counter is added when the rotation direction of the rotation member is the reference rotation direction, the count value is added when the rotation member rotates in the reference rotation direction.

  As a result, the remaining amount detection unit can detect the remaining amount of paper using the count value when the rotating member rotates in the reference rotation direction, so that the detection error of the remaining amount of paper due to slight vibration can be reduced. it can.

  In the above configuration, the level value output unit is configured such that the light receiving elements are arranged in a row starting from a reference light receiving element which is a predetermined light receiving element, and the last light receiving element is the rotation member. The predetermined angle is such that when the rotating member rotates in the reference rotation direction, a light receiving region located at a position opposite to the non-transmissive region is located on the rearmost side. The angle is preferably changed from the light receiving element toward the light receiving element on the reference light receiving element side.

  According to this configuration, when the rotating member rotates in the reference rotation direction, the light receiving element located at the position facing the non-transmissive region changes from the rearmost light receiving element toward the first reference light receiving element.

  As a result, if the information indicating that the light receiving element located at the opposite position of the non-transmissive region changes from the last light receiving element toward the first reference light receiving element side is used as the reference information, the rotating member rotates the reference rotation. You can see that it is rotating in the direction.

  As a result, it is determined that the rotating member is rotating in the reference rotation direction based on the change in the received light level value obtained by the level value output unit and the reference information, and erroneous detection is performed based on the determination result. The suppressed remaining amount of paper can be detected.

  In the above configuration, the level value output unit is configured such that, among the light receiving elements that do not receive the light among the light receiving elements, the specific light receiving element that is the light receiving element located at the forefront is the light receiving element of It is preferable to output a different light reception level value depending on which of the above.

  According to this configuration, when there are a plurality of light receiving elements that do not receive light, different light reception level values are output depending on which one of the light receiving elements is the most specific light receiving element. Even when the light receiving element located at the position opposed to the non-transmissive region changes in units of a plurality of light receiving elements in accordance with the rotation of the light receiving element, it is possible to acquire different light receiving level values depending on the rotation direction of the rotating member.

  In the above configuration, the level value output unit is configured such that, among the light receiving elements that receive light among the light receiving elements, the specific light receiving element that is the light receiving element located at the foremost side is the light receiving element among the light receiving elements. It is preferable to output a different light reception level value depending on which of the above.

  According to this configuration, when there are a plurality of light receiving elements that receive light, different light reception level values are output depending on which one of the light receiving elements is the most specific light receiving element, so that the transmission region Even when the light receiving elements located at the opposite positions of the plurality of light receiving elements change in units of a plurality of light receiving elements, different light receiving level values can be acquired according to the rotation direction of the rotating member.

  In the above configuration, it is preferable that the level value output unit outputs a light reception level value that is smaller as the specific light receiving element approaches the reference light receiving element.

  According to this configuration, as the specific light receiving element approaches the first reference light receiving element, a smaller light reception level value is output. Therefore, the rotating member rotates in the reference rotation direction and is positioned at a position opposite to the non-transmissive region or the transmissive region. When the light receiving element changes from the last light receiving element toward the first reference light receiving element, it is possible to acquire light receiving level values that are sequentially decreased.

  As a result, it is possible to determine that the rotating member is rotating in the reference rotation direction when the level value output unit obtains light reception level values that are sequentially reduced.

  In the above configuration, it is preferable that the level value output unit outputs a larger light reception level value as the specific light receiving element approaches the reference light receiving element.

  According to this configuration, as the specific light receiving element approaches the first reference light receiving element, a larger light reception level value is output. Therefore, the rotating member rotates in the reference rotation direction and is positioned at a position opposite to the non-transmissive region or the transmissive region. When the light receiving element changes from the last light receiving element toward the first reference light receiving element, it is possible to acquire light reception level values that sequentially increase.

  As a result, it is possible to determine that the rotating member is rotating in the reference rotation direction when the level value output unit obtains sequentially received light level values.

  According to another aspect of the present invention, there is provided an image forming apparatus according to the above-described sheet remaining amount detecting device, a conveying unit that takes out and conveys a sheet accommodated in the sheet accommodating unit, and a sheet conveyed by the conveying unit. And an image forming unit that forms an image.

  According to this configuration, since the above-described remaining sheet amount detecting device is provided, it is possible to reduce the remaining sheet amount detection error due to slight vibration.

  According to the present invention, it is possible to reduce the detection error of the remaining amount of paper due to slight vibration.

1 is a schematic cross-sectional view illustrating an example of an image forming apparatus according to an embodiment of the present invention. It is the figure which showed notionally an example of the external appearance of a stocker. 3 is a block diagram illustrating an example of a functional module of a remaining paper amount detection device. FIG. It is a figure showing the correspondence between a motor, a rotation member, a photo interrupter, and a 1st tray. It is the figure which showed an example of the positional relationship between a rotation member and a photo interrupter. It is the top view which showed an example of the external appearance of a light-receiving part. It is explanatory drawing which showed an example of the voltage value output from a light-receiving part. It is explanatory drawing which showed the other example of the voltage value output from a light-receiving part. It is explanatory drawing which showed an example of the change of the light receiving element which is not light-receiving in a light-receiving part. It is explanatory drawing which showed an example of the change of the voltage value obtained by a light-receiving part when a rotation member rotates to a reference | standard rotation direction. It is explanatory drawing which showed an example of the change of the voltage value obtained by a light-receiving part when a rotation member rotates in the reverse direction to a reference | standard rotation direction. It is the flowchart which showed an example of the outline | summary of the process of a count control part. 5 is a flowchart illustrating an example of an outline of a remaining paper detection process. It is a time chart for demonstrating the conventional paper remaining amount detection apparatus. It is a time chart for demonstrating the conventional paper remaining amount detection apparatus.

  Hereinafter, a sheet remaining amount detection device and an image forming apparatus according to an embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an example of an image forming apparatus according to an embodiment of the present invention. The image forming apparatus shown in FIG. 1 includes a remaining paper amount detection apparatus 1 (see FIG. 3) according to an embodiment of the present invention.

  As shown in FIG. 1, the image forming apparatus A includes a housing 2 that is formed in a substantially rectangular parallelepiped, a storage unit 3 that is disposed in the lower part of the internal space of the housing 2 and stores the paper SH, and a storage unit 3. The sheet SH is taken out from the sheet SH and conveyed, the image forming unit 5 forms a toner image on the surface of the sheet SH in the middle of conveyance, and the fixing for fixing the toner image formed on the sheet SH on the sheet SH. A unit 6 and a discharge unit 7 for discharging the paper SH on which the toner image is fixed to the outside of the housing 2. A document reading unit 8 for reading a document image is disposed on the upper portion of the housing 2. The document reading unit 8 reads an image of a document and converts it into electronic data.

  The storage unit 3 includes a first cartridge 31 and a second cartridge 32 that store a small bundle of sheets SH. The second cartridge 32 is disposed above the first cartridge 31. The storage unit 3 further includes a stocker (paper storage unit) 33 for storing the number of sheets SH that can be stored in the first cartridge 31 and the second cartridge 32. The stocker 33 is disposed above the second cartridge 32.

  The stocker 33 includes a substantially rectangular plate-shaped bottom 331 and a peripheral wall 332 extending upward from the periphery of the bottom 331. The upper edge of the peripheral wall portion 332 forms an opening of the stocker 33. The paper SH accommodated in the internal space of the stocker 33 defined by the bottom 331 and the peripheral wall 332 is taken out by the transport unit 4 through the opening formed in the upper part of the stocker 33 and transported toward the image forming unit 5. Is done. The first cartridge 31, the second cartridge 32, and the stocker 33 are provided so that they can be pulled out from the inside of the housing 2.

  The stocker 33 includes a partition plate 333 disposed across the internal space of the stocker 33. The partition plate 333 extends upward from the bottom portion 331 and partitions the internal space of the stocker 33 into small spaces adjacent to each other in FIG. The small space formed on the left side forms the first housing portion 33A, and the small space formed on the right side forms the second housing portion 33B.

  The transport unit 4 includes a transport path 43 that extends in the vertical direction on the right side of the storage unit 3. The paper SH taken out from the stocker 33 by the paper take-out rollers 413A and 414A is transported to the transport path 43 by the belt device 412 and travels toward the image forming unit 5 through the transport path 43.

  The paper extraction roller 413A is provided in the first roller device 413, and the paper extraction roller 414A is provided in the second roller device 414. The first roller device 413 and the second roller device 414 are attached to the housing 2 so as to be rotatable, and are pushed upward by the paper SH placed on the stocker 33 so as to be between the horizontal plane. The angle of fluctuates.

  And when the angle between the first roller device 413 and the horizontal surface of the second roller device 414 becomes a preset angle, a force that pushes the first roller device 413 and the second roller device 414 upward is applied. The generated motor stops driving.

  The transport unit 4 further includes a pickup roller 44 disposed near the upper right corner of the first cartridge 31 and the second cartridge 32, and a separation / feed roller 45 disposed downstream of the pickup roller 44. . The pickup roller 44 and the separation / feed roller 45 take out the sheet SH from the first cartridge 31 and the second cartridge 32 one by one and convey the sheet SH to the conveyance path 43. The transport unit 4 further includes a plurality of transport rollers 46 disposed along the transport path 43. The transport roller 46 transports the paper SH sent from the stocker 33, the first cartridge 31, or the second cartridge 32 to the image forming unit 5 through the transport path 43.

  The image forming unit 5 includes a substantially cylindrical photosensitive drum 51 that is rotatably supported by the housing 2, and a charger 52 disposed above the photosensitive drum 51. The photosensitive drum 51 rotates clockwise in FIG. The charger 52 applies a charge to the photosensitive drum 51 and uniformly charges the circumferential surface of the photosensitive drum 51. The image forming unit 5 further includes an exposure device 53. The exposure device 53 irradiates the charged peripheral surface of the photosensitive drum 51 with laser light based on image data obtained by the original reading unit 8 reading an image of the original. As a result, the laser light loses the electric charge on the photosensitive drum 51, so that an electrostatic latent image matching the image data is formed on the photosensitive drum 51. The image forming unit 5 further includes a developing device 54. The developing device 54 includes a toner container 55 that contains toner, and supplies the toner from the toner container 55 to the peripheral surface of the photosensitive drum 51 on which the electrostatic latent image is formed. As a result, a toner image that matches the electrostatic latent image is formed on the peripheral surface of the photosensitive drum 51.

  The image forming unit 5 further includes a transfer belt 56 disposed below the photosensitive drum 51. The sheet SH is sent between the photosensitive drum 51 and the transfer belt 56 through the conveyance path 43. When the sheet SH passes between the photosensitive drum 51 and the transfer belt 56, the toner image formed on the peripheral surface of the photosensitive drum 51 is applied to the sheet SH by applying a reverse bias having a polarity opposite to that of the toner. It will be transcribed.

  The image forming unit 5 further includes a cleaning device 57 that removes the toner remaining on the peripheral surface of the photosensitive drum 51 after the toner image is transferred to the paper SH, and the periphery of the photosensitive drum 51 from which the residual toner has been removed. And a static eliminator 58 for removing residual charges from the surface.

  The paper SH on which the toner image is transferred in the image forming unit 5 is sent to the fixing unit 6. The fixing unit 6 includes a fixing roller 61 and a pressure roller 62 that is pressed against the fixing roller 61. A heat source 63 is disposed inside the fixing roller 61, and the toner on the paper SH passing between the fixing roller 61 and the pressure roller 62 is melted, and the pressure on the paper SH is increased by the pressure from the pressure roller 62. The toner is fixed on the surface. As a result, the toner image is fixed on the sheet SH.

  The discharge unit 7 is disposed downstream of the fixing unit 6 and is mounted near the inner wall surface of the housing 2, and a discharge tray 72 that receives the paper SH discharged from the discharge roller 71 to the outside of the housing 2. Including.

  The image forming apparatus A shown in FIG. 1 includes a conveyance path 47 for double-sided printing between the stocker 33 and the image forming unit 5 / fixing unit 6. The discharge roller 71 can also send out the paper SH to the transport path 47 by a switchback method. The conveyance path 47 joins immediately before the registration roller 48 disposed in the middle of the conveyance path 43. The sheet SH that has passed through the conveyance path 47 is sent to the image forming unit 5 by the registration roller 48, and the toner image is transferred to the surface of the image forming unit 5 where the toner image is not fixed. Thereafter, the toner image newly transferred by the fixing unit 6 is fixed onto the paper SH. Finally, the sheet SH is discharged onto the discharge tray 72 by the discharge roller 71.

  FIG. 2 is a diagram conceptually illustrating an example of the appearance of the stocker 33. In FIG. 2, the same components as those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.

  In the stocker 33, a first tray 334 is disposed in the first storage portion 33A. A second tray 335 is disposed in the second storage portion 33B. The first tray 334 includes an upper surface for placing a bundle of sheets SH. The second tray 335 also has an upper surface for placing a bundle of sheets SH.

  The first tray 334 and the second tray 335 are configured to be movable in the vertical direction between the replenishment position PL and the paper feed position PH set in advance in the stocker 33.

  The replenishment position PL is a position where the upper surface of the tray is positioned when the first tray 334 and the second tray 335 come into contact with the bottom 331 of the stocker 33. The paper feed position PH is a position for taking out the uppermost sheet SH on the first tray 334 and the second tray 335.

  The first tray 334 and the second tray 335 move in the vertical direction of the stocker 33 when the motor M is driven. The motor M is controlled and driven by the control unit 10.

  The stocker 33 having such a configuration accepts the replenishment of the paper SH with the upper surfaces of the first tray 334 and the second tray 335 positioned at the replenishment position PL. When the paper is replenished on the tray, the tray is raised by driving the motor M. Then, when the uppermost sheet SP on the tray reaches the sheet feeding position PH, the raising of the tray is stopped.

  The paper SH on the tray is sequentially taken out from the uppermost paper SH on the tray at the paper feed position PH. As the sheet SH on the tray decreases, the tray is raised by driving the motor M so that the uppermost sheet SH on the tray is always located at the sheet feeding position PH.

  Hereinafter, an example of the configuration of the remaining sheet quantity detection device 1 including the stocker 33 in FIG. 2 will be described with reference to FIGS. 3 and 4. FIG. 3 is a block diagram illustrating an example of a functional module of the remaining paper amount detection device 1. FIG. 4 is a diagram showing a correspondence relationship among the motor M, the rotating member 20, the photo interrupter 50, and the first tray 334 in the remaining paper amount detection device 1 of FIG.

  In the following description, the configuration related to the second tray 335 is the same as the configuration related to the first tray 334 described below, and thus the description and illustration thereof are omitted.

  The sheet remaining amount detection device 1 includes the stocker 33, the motor M such as a DC motor, the plate-like rotating member 20 that rotates in conjunction with the rotation of the motor M, the photo interrupter 50, the control unit 10, and a storage unit. 60. The photo interrupter 50 includes a light emitting unit (light output unit) 50A and a light receiving unit (level value output unit) 50B. The photo interrupter 50 is arranged so that the rotating member 20 is sandwiched between the light emitting unit 50A and the light receiving unit 50B. As the photo interrupter 50, for example, a known end detection device described in JP 2010-256020 A can be used. In FIG. 4, the light emitting unit 50 </ b> A is disposed at a position hidden behind the rotating member 20, and the illustration thereof is omitted.

In the stocker 33, the fixed pulleys P1 and P1 are fixed to the housing 2 as shown in FIG.
Two wires W, W are stretched over the fixed pulleys P1, P1, and one end of each wire W is fixed to the left end and the right end of the first tray 334, respectively, and the other end of each wire W is fixed. Is fixed to the pulley 341.

  The pulley 341 is connected to and connected to the rotation axis AX of the motor M. Alternatively, the pulley 341 is connected to the rotation axis AX via a gear mechanism (not shown).

  When the pulley 341 rotates in the clockwise direction (the direction indicated by the solid line arrow in FIG. 4), the first tray 334 rises because each wire W is wound around the pulley 341. On the other hand, when the pulley 341 rotates counterclockwise (in the direction of the dotted line arrow in FIG. 4), the first tray 334 descends because each wire W is fed out from the pulley 341.

  The motor M is controlled by the control unit 10 to raise the first tray 334. Specifically, when the upper surface of the first tray 334 is located at the replenishment position PL (see FIG. 2), the motor M rotates its rotation axis AX in the counterclockwise direction (solid arrow direction) in FIG. As a result, the pulley 341 is rotated in the clockwise direction (the direction indicated by the solid arrow in FIG. 4). As a result, the first tray 334 rises from the replenishment position PL in the direction of the paper feed position PH (see FIG. 2).

  On the other hand, when the motor M rotates its rotation axis AX in the clockwise direction (dotted arrow direction) in FIG. 4, the pulley 341 rotates in the counterclockwise direction (dotted arrow direction in FIG. 4). One tray 334 descends.

  Here, FIG. 5 is a diagram illustrating an example of a positional relationship between the rotating member 20 and the photo interrupter 50.

  As shown in FIGS. 4 and 5, in the rotating member 20, transmissive regions 20 </ b> A represented by white and non-transmissive regions 20 </ b> B represented by hatching are alternately arranged in the circumferential direction. The rotating member 20 is made of, for example, a resin disk, and the transmission region 20A is formed of a transparent portion that transmits light, and the non-transmission region 20B is formed of a black portion that does not transmit light.

  When the motor M rotates in the counterclockwise direction (solid arrow direction in FIG. 4: reference rotation direction) to raise the first tray 334, the rotation member 20 rotates in the reference rotation direction, for example, counterclockwise. Rotate clockwise.

  The transmissive region 20A and the non-transmissive region 20B are fan-shaped regions that are defined by two radii of the rotating member 20 and one arc.

  The transmissive region 20 </ b> A and the non-transmissive region 20 </ b> B have end portions 21 that extend along the radial direction of the rotating member 20. The end 21 is a boundary between the transmissive region 20A and the non-transmissive region 20B. The transmissive region 20A transmits the light output from the light emitting unit 50A, and the non-transmissive region 20B blocks the light output from the light emitting unit 50A.

  The rotating member 20 is pivotally supported so that the center point of the rotating member 20 is positioned on the rotation axis AX of the motor M, and rotates in the same direction as the rotation direction of the rotation axis AX. The rotating member 20 is not limited to the example that is supported on the rotating shaft AX.

  For example, the rotation member 20 may receive the rotational force of the rotation axis AX relayed by a gear. Alternatively, the rotating member 20 may rotate a plurality of times while the motor M rotates once, and the rotating member 20 may rotate once while the motor M rotates a plurality of times. That is, the rotating member 20 may be rotated in conjunction with the rotation of the motor M.

  In the photo interrupter 50, the light emitting part 50A and the light receiving part 50B are formed in a substantially rectangular parallelepiped shape. As shown in FIGS. 4 and 5, the longitudinal direction of the light emitting unit 50A and the light receiving unit 50B and the radial direction of the rotating member 20 are a predetermined angle θ (where 0 ° <θ <180 °, more preferably (0 ° <θ ≦ 90 °).

  The light receiving unit 50B is disposed to face the rotating member 20. In the light receiving unit 50B, as shown in FIG. 5, the light receiving elements 50B (1) to 50B (6) are arranged with the light receiving element 50B (1) as the leading reference light receiving element.

  In the light receiving unit 50B, the light receiving element 50B (1) is arranged in the order in which the rearmost light receiving element 50B (6) is positioned closest to the center of the rotating member 20 among the light receiving elements along the longitudinal direction of the light receiving unit 50B. ˜50B (6) is arranged. Then, each of the light receiving elements 50B (1) to 50B (6) receives light transmitted from the light emitting unit 50A disposed opposite to the light receiving unit 50B and the rotating member 20 and transmitted through the transmission region 20A.

  When the end 21 of the transmission region 20A passes through the light receiving unit 50B, the light receiving unit 50B forms an angle θ greater than 0 between the end 21 of the transmission region 20A and the longitudinal direction of the light receiving unit 50B. Has been placed.

  Here, when the entirety of the light receiving unit 50B is arranged to face the transmission region 20A as shown in FIG. 5, the predetermined angle θ is the direction in which the rotary member 20 corresponds to the reference rotation direction, that is, the direction of the solid arrow. When the light receiving element rotates, the light receiving element that does not receive light is received from the light receiving element on the light receiving element 50B (6) side (for example, from the light receiving element 50B (6) as described later) to the light receiving element 50B (1) side. The angle changes toward the element (for example, the light receiving element 50B (1) as described later).

  Returning to FIG. 4, in the photo interrupter 50, the light emitting unit 50 </ b> A outputs light toward the light receiving unit 50 </ b> B. The light receiving unit 50B receives the light output from the light emitting unit 50A, and outputs different light reception level values depending on which of the light receiving elements is a light receiving element that is not receiving light.

  Hereinafter, the configuration of the light receiving unit 50B will be described with reference to FIGS.

  FIG. 6 is a plan view showing an example of the appearance of the light receiving unit 50B. FIG. 7 is an explanatory diagram illustrating an example of a voltage value output from the light receiving unit 50B. FIG. 8 is an explanatory diagram showing another example of the voltage value output from the light receiving unit 50B.

  In the following description, it is assumed that a voltage value is output as the light receiving level value from the light receiving unit 50B.

  In the light receiving unit 50B, as shown in FIG. 6, a plurality of light receiving elements 50B (1) to 50B (6) are arranged in a line with the light receiving element 50B (1) as a leading reference light receiving element.

  The light receiving unit 50B has different voltage values depending on which light receiving element is the specific light receiving element which is the light receiving element located on the most front light receiving element 50B (1) side among the light receiving elements not receiving light. Is output. The light receiving unit 50B is configured such that the voltage value decreases as the specific light receiving element is closer to the leading light receiving element 50B (1).

  Specifically, when all the light receiving elements receive light as shown in FIG. 7G, the light receiving unit 50B outputs a predetermined voltage value, for example, a voltage signal of 6V.

  In the light receiving unit 50B, a voltage value of a voltage signal to be output when each light receiving element becomes a light receiving element not receiving light is determined in advance corresponding to each light receiving element.

  When any one of the light receiving elements is not receiving light, the light receiving unit 50B outputs a voltage signal having a voltage value corresponding to the specific light receiving element among the light receiving elements that are not receiving light (off). In this case, the on / off state of the light receiving element subsequent to the specific light receiving element is ignored.

  For example, as shown in FIG. 7A, when the light receiving element 50B (1) is not receiving light, the light receiving unit 50B receives the light receiving elements 50B (2) to 50B (6) subsequent to the light receiving element 50B (1). A voltage signal of 0 V is output regardless of whether or not light is received.

  As shown in FIG. 7B, when the light receiving element 50B (1) receives light and the light receiving element 50B (2) does not receive light, the light receiving unit 50B is more than the light receiving element 50B (2). Regardless of whether the subsequent light receiving elements (3) to 50B (6) receive light, a voltage signal of 1 V is output.

  Further, as shown in FIG. 7C, when the light receiving element 50B (1) and 50B (2) receive light and the light receiving element 50B (3) does not receive light, the light receiving unit 50B receives the light receiving element. Regardless of whether the light receiving elements 50B (4) to 50B (6) subsequent to 50B (3) receive light, a voltage signal of 2V is output.

  Further, as shown in FIG. 7D, when the light receiving element 50B (1) to 50B (3) receives light and the light receiving element 50B (4) does not receive light as shown in FIG. Regardless of whether or not the light receiving elements 50B (5) and 50B (6) subsequent to 50B (4) receive light, a voltage signal of 3V is output.

  Further, as shown in FIG. 7E, the light receiving unit 50B receives the light receiving elements 50B (1) to 50B (4) and the light receiving element 50B (5) is not receiving light. Regardless of whether the light receiving element 50B (6) subsequent to 50B (5) is receiving light, a voltage signal of 4 V is output.

  Further, as shown in FIG. 7F, the light receiving unit 50B outputs a voltage signal of 5 V when the light receiving element 50B (6) at the rearmost stage is not receiving light.

  In this case, the voltage value output from the light receiving unit 50B is shown in FIG. 10 when the rotating member 20 rotates forward (rotates in the reference rotation direction), and shown in FIG. 11 when the rotating member 20 rotates reversely. .

  In FIG. 7, the light receiving unit 50B outputs a voltage signal having a smaller voltage value as the specific light receiving element among the light receiving elements that do not receive light approaches the leading light receiving element 50B (1). A voltage signal having a larger voltage value may be output as the specific light receiving element approaches the first light receiving element 50B (1).

  In this case, the voltage value output from the light receiving unit 50B is shown in FIG. 11 when the rotating member 20 rotates forward, and is shown in FIG. 10 when the rotating member 20 rotates reversely.

  Here, among the light receiving elements receiving light, the light receiving element located on the most front light receiving element 50B (1) side may be the specific light receiving element. In this case, the relationship between the on / off state of each light receiving element and the voltage value obtained by the light receiving unit 50B is as shown in FIG.

  In this case, the light receiving unit 50B outputs a voltage signal of 6V that is the highest voltage value when all the light receiving elements are not receiving light, and the specific light receiving element among the light receiving elements that are receiving is the last light receiving element 50B. From (6), the voltage signal of a small voltage value is sequentially output as it approaches the first light receiving element 50B (1) which is the reference light receiving element.

  Even in this case, even if the specific light receiving element among the light receiving elements receiving light approaches the first light receiving element 50B (1) from the last light receiving element, a voltage signal having a large voltage value may be output sequentially. Good.

  The light receiving element 50B may be “off” when receiving light, and “on” when not receiving light. In this case, FIG. 7 and FIG. 8 are interchanged.

  In the present embodiment, the light receiving unit 50B outputs a voltage value as the light receiving level value, but is not limited to this example, and may be a current value or a digital value.

Returning to FIG. 3, the control unit 10 comprehensively controls the remaining paper amount detection device 1. The control unit 10
A CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and the like are configured, and the CPU is realized by executing a predetermined control program.

  The storage unit 60 stores, as reference information, information indicating a change in the received light level value to be output by the light receiving unit 50B when the transmission region 20A of the rotating member 20 passes through the position facing the light emitting unit 50A and the light receiving unit 50B. To do. In addition, the storage unit 60 stores information indicating the correspondence between the count value and the remaining amount of paper.

  The control unit 10 includes a counter 11, a count control unit 12, and a remaining amount detection unit 13. Under the control of the count control unit 12, the counter 11 adds count values one by one.

  The count control unit 12 adds the count values in the counter 11 one by one based on the reference information stored in the storage unit 60 and the change in the received light level value obtained by the light receiving unit 50B.

  The remaining amount detection unit 13 detects the remaining amount of paper on the first tray 334 based on information indicating the correspondence between the count value in the counter 11 and the remaining amount of paper.

  Hereinafter, the reference information stored in the storage unit 60 will be described with reference to FIGS. 9 and 10. Here, FIG. 9 is a diagram illustrating an example of a change in a light receiving element that does not receive light in the light receiving unit 50B. FIG. 10 is an explanatory diagram showing an example of a change in voltage value obtained by the light receiving unit 50B when the rotating member 20 rotates in the reference rotation direction.

  In the light receiving section 50B of FIG. 9, the light receiving element 50B (6) is arranged on the upper left side, and the light receiving elements 50B (5) to 50B (1) are moved to the lower right direction, and the light receiving elements 50B (5). To the light receiving element 50B (1).

  In FIG. 9A, since each light receiving element is located at a position opposite to the transmission region 20A, the voltage value obtained by the light receiving unit 50B is 6V.

  When the rotating member 20 rotates in the direction of the solid line arrow, the light receiving elements 50B (1) to 50B (5) are located at the opposed positions of the transmissive area 20A as shown in FIG. 9B, and are opposed to the non-transmissive areas 20B. The light receiving element 50B (6) is located at the position. In this case, the light receiving unit 50B outputs a voltage signal of 5V.

  Further, when the rotating member 20 rotates in the direction of the solid line arrow, as shown in FIG. 9C, the light receiving elements 50B (1) to 50B (4) are located at the opposed positions of the transmissive region 20A, and are opposed to the non-transmissive region 20B. The light receiving elements 50B (5) and 50B (6) are located at the positions. In this case, since the light receiving element 50B (5) close to the first light receiving element 50B (1) among the light receiving elements 50B (5) and 50B (6) is not receiving light, the light receiving unit 50B outputs a voltage signal of 4V. .

  Further, when the rotating member 20 rotates in the direction of the solid line arrow, as shown in FIG. 9D, the light receiving elements 50B (1) to 50B (3) are located at the opposed positions of the transmissive region 20A, and are opposed to the non-transmissive region 20B. The light receiving elements 50B (4) to 50B (6) are located at the positions. In this case, among the light receiving elements 50B (4) to 50B (6), the light receiving element 50B (4) close to the first light receiving element 50B (1) is not receiving light, and therefore the light receiving unit 50B outputs a voltage signal of 3V. .

  Further, when the rotating member 20 rotates in the direction of the solid line arrow, as shown in FIG. 9E, the light receiving elements 50B (1) and 50B (2) are positioned at the opposed positions of the transmissive area 20A, and are opposed to the non-transmissive areas 20B. The light receiving elements 50B (3) to 50B (6) are located at the positions. In this case, since the light receiving element 50B (3) close to the first light receiving element 50B (1) among the light receiving elements 50B (3) to 50B (6) is not receiving light, the light receiving unit 50B outputs a voltage signal of 2V. .

  Further, when the rotating member 20 rotates in the direction of the solid line arrow, as shown in FIG. 9 (f), the light receiving element 50B (1) is positioned at the position facing the transmissive region 20A, and the light receiving element 50B is positioned at the position facing the non-transmissive region 20B. (2) to 50B (6) are located. In this case, since the light receiving element 50B (2) close to the first light receiving element 50B (1) among the light receiving elements 50B (2) to 50B (6) is not receiving light, the light receiving unit 50B outputs a voltage signal of 1V. .

  Further, when the rotating member 20 rotates in the direction of the solid line arrow, each light receiving element is positioned at a position facing the non-transmissive region 20B as shown in FIG. In this case, since the first light receiving element 50B (1) is not receiving light, the light receiving unit 50B outputs a voltage signal of 0V.

  Further, in FIG. 9G, when the rotating member 20 rotates in the direction of the solid line arrow, the end 21 (1) moves from the facing position of the light receiving element 50B (6) toward the facing position of the light receiving element 50B (1). And finally, it returns to the state of Fig.9 (a). During this period, since the leading light receiving element 50B (1) is not receiving light, the light receiving unit 50B outputs a voltage signal of 0V.

  Thus, when the rotating member 20 starts to rotate in the direction of the solid arrow from the state where each light receiving element is located at the position opposed to the transmission region 20A, until the top light receiving element 50B (1) does not receive light, That is, during the time T, the voltage value obtained by the light receiving unit 50B decreases from 6V to 0V, and the time from when the leading light receiving element 50B stops receiving light until it receives light again, that is, during time T1. Maintains 0V (see FIG. 10).

  If the rotating member 20 starts to rotate in the direction opposite to the solid arrow direction from the state shown in FIG. 9A, the light receiving element facing the non-transmissive region 20B receives light from the light receiving element 50B (1). It changes toward the element 50B (6), and then changes to the light receiving element 50B (1).

  In this case, as shown in FIG. 11, during the time T from when the light receiving element facing the non-transmissive region 20B is the light receiving element 50B (1) to returning to the light receiving element 50B (1) again, The voltage value obtained by the light receiving unit 50B increases from 0V to 6V and instantaneously decreases to 0V.

  For this reason, the remaining paper amount detection device 1 has a case where the change in the voltage value obtained by the light receiving unit 50B is a gradual decrease, that is, when the decrease amount of the voltage value per unit time is equal to or less than a preset reference value. Can detect that the rotating member 20 is rotating in the reference rotation direction.

  On the other hand, when the change in the voltage value obtained by the light receiving unit 50B is a gradual increase, that is, the amount of increase in the voltage value per unit time is equal to or less than a preset reference value, the remaining paper amount detection device 1 It can be detected that the rotating member 20 is rotating in the direction opposite to the reference rotation direction.

  As a result, by detecting that the change in the voltage value obtained by the light receiving unit 50B is the change shown in FIG. 10, it is possible to detect that the rotating member 20 is rotating in the reference rotation direction without reciprocating.

  Thereby, in the storage unit 60, information indicating changes shown in FIG. 10 is stored as reference information as information indicating that the rotating member 20 has rotated in the reference rotation direction.

  Returning to FIG. 3, when the change in the voltage value Vs obtained by the light receiving unit 50B coincides with the change represented by the reference information, the count control unit 12 regards the rotating member 20 as rotating in the reference rotation direction. One count value in the counter 11 is added. On the other hand, when the change in the voltage value Vs obtained by the light receiving unit 50B does not coincide with the change represented by the reference information, the count control unit 12 does not regard the rotating member 20 as rotating in the reference rotation direction and the counter 11 Do not add the count value.

  Hereinafter, an outline of the processing of the count control unit 12 will be described with reference to FIG. FIG. 12 is a flowchart showing an example of an outline of processing of the count control unit 12. The flowchart shown in FIG. 12 shows an example of the operation of the count control unit 12 based on the reference information shown in FIGS.

  The count control unit 12 first clears the count value in the counter 11 (step S1).

  When the count control unit 12 detects that the voltage value Vs obtained by the light receiving unit 50B has changed from 0V to 6V within a preset time in order to detect a steep rise (step S2). YES), the process proceeds to step S3. Then, the count control unit 12 determines whether or not the subsequent change in the voltage value Vs is a change in a direction in which the change gradually decreases (step S3).

  When the count control unit 12 determines that the change in the voltage value Vs is a gradual decrease (YES in step S3), the count control unit 12 determines whether the voltage value Vs has become 0 V (step S4). When Vs becomes 0 V (YES in step S4), the count value in the counter 11 is incremented by one (step S5). On the other hand, when the count control unit 12 determines that the change in the voltage value Vs is not a gradual decrease (a gradual increase) (NO in step S3), the count control unit 12 proceeds to step S3 without adding the count value.

  With the above processing, the count control unit 12 determines whether or not the change in the voltage value Vs obtained by the light receiving unit 50B matches the change represented by the reference information. Add values.

  As a result, the remaining paper amount detection device 1 adds the count value when the rotating member 20 rotates in the reference rotation direction without reciprocating, and detects the remaining paper amount using the count value. It becomes possible. As a result, erroneous detection of the remaining amount of paper due to slight vibration of the rotating member 20 can be reduced.

  Hereinafter, the remaining sheet detection process in the remaining sheet detection device 1 will be described with reference to FIG. FIG. 13 is a flowchart illustrating an example of an outline of the remaining sheet detection process. FIG. 13 shows a process for detecting the remaining amount of paper on the first tray 334. However, for the process for detecting the remaining amount of paper on the second tray 335, the remaining paper on the first tray 334 is shown. Since it is the same as the process which detects quantity, description is abbreviate | omitted.

  The controller 10 drives the motor M to raise the first tray 334 so that the uppermost sheet SH on the first tray 334 is positioned at the sheet feeding position PH (step S10). Then, the rotation member 20 rotates with the drive of the motor M, and the voltage value obtained by the light receiving unit 50B changes. Therefore, the count control unit 12 acquires the voltage value obtained by the light receiving unit 50B (step S11). Then, it is determined whether or not the change in voltage value matches the change represented by the reference information (step S12).

  When the change in the voltage value matches the change represented by the reference information (YES in step S12), the count control unit 12 regards the rotating member 20 as rotating in the reference rotation direction and determines the count value in the counter 11 One is added (step S13).

  On the other hand, when the change in the voltage value does not coincide with the change represented by the reference information (NO in step S12), the count control unit 12 does not add the count value in the counter 11.

  The remaining amount detection unit 13 detects the remaining amount of paper on the first tray 334 based on the information indicating the correspondence between the count value in the counter 11 and the remaining amount of paper (step S14), and detects the detected remaining paper amount. For example, the amount is displayed on a display unit (not shown).

A Image forming apparatus 1 Paper remaining amount detecting device 4 Conveying unit 5 Image forming unit 11 Counter 12 Count control unit 13 Remaining amount detecting unit 20 Rotating member 20A Transmission region 20B Non-transmission region 33 Stocker (paper storage unit)
50 Photo interrupter 50A Light emitting part (light output part)
50B Light receiving part (level value output part)
50B (1) to 50B (6) Light receiving element 60 Storage unit 334 First tray 335 Second tray M Motor SH Paper PH Paper feed position

Claims (8)

A paper storage section for storing paper;
A tray provided for placing the paper and movable in the vertical direction inside the paper storage portion;
A motor for rotating the tray in a reference rotation direction set in advance so that the uppermost sheet placed on the tray is positioned at a predetermined paper feed position;
A plate-like rotating member that rotates in conjunction with the rotation of the motor, and a transmission region that transmits light and a non-transmission region that does not transmit light are alternately aligned along the rotation direction of the rotation member. An arranged rotating member;
A plurality of light receiving elements are arranged in a line, and each light receiving element and the rotating member are opposed to each other with a predetermined angle between the arrangement direction of the light receiving elements and the radial direction of the rotating member. A level value output unit that outputs a different light reception level value according to the received light receiving element;
A light output section that is disposed opposite to each light receiving element with the rotating member interposed therebetween, and that outputs light toward each light receiving element;
Information indicating a change in the received light level value to be output by the level value output unit when the transmission region passes through a position facing the light output unit in a direction corresponding to the reference rotation direction is stored as reference information. A storage unit to
A counter,
A count control unit for adding a count value in the counter based on the reference information and the change in the light reception level value obtained by the level value output unit;
A remaining amount detection unit that detects the remaining amount of the sheet using the count value obtained by the counter;
A sheet remaining amount detecting device comprising: The count control unit
Based on the change in the received light level value obtained by the level value output unit and the reference information, the rotation direction of the rotating member is determined, and when the determined rotation direction is the reference rotation direction, the counter The remaining paper amount detecting device according to claim 1, wherein the count value is added. The level value output unit
Each of the light receiving elements is arranged in a row starting from a reference light receiving element which is a predetermined light receiving element, and the last light receiving element is arranged to be located on the center side of the rotating member,
The predetermined angle is
When the rotating member rotates in the reference rotation direction, an angle at which a light receiving region located at a position opposite to the non-transmissive region changes from the light receiving element on the rearmost side toward the light receiving element on the reference light receiving element side The remaining paper amount detection device according to claim 1, wherein the remaining amount of paper is detected. The level value output unit
Among the light receiving elements that do not receive light among the light receiving elements, the light receiving level that varies depending on which of the light receiving elements is the specific light receiving element that is the light receiving element located at the foremost side. The paper remaining amount detection device according to claim 3, wherein a value is output. The level value output unit
Among the light receiving elements that receive light among the light receiving elements, the light receiving level that differs depending on which of the light receiving elements is the specific light receiving element that is the light receiving element located at the foremost side. The paper remaining amount detection device according to claim 3, wherein a value is output. The level value output unit
The sheet remaining amount detection apparatus according to claim 4, wherein the specific light receiving element outputs a smaller light reception level value as it approaches the reference light receiving element. The level value output unit
6. The sheet remaining amount detection device according to claim 4, wherein the specific light receiving element outputs a larger light reception level value as it approaches the reference light receiving element. A remaining paper amount detection device according to any one of claims 1 to 7,
A transport unit that takes out and transports the paper stored in the paper storage unit;
An image forming unit that forms an image on the sheet conveyed by the conveying unit;
An image forming apparatus comprising:

Images