JP2012053201A - Cartridge and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cartridge capable of precisely detecting that the remaining quantity of developer becomes small, and an image forming apparatus having the same.SOLUTION: In a toner storage chamber 12, a scooping member 62 is provided such that it can rotate around a center axis line 66 of a rotating shaft 61 common to an agitating member 63 in the same direction as the rotation direction of the agitating member 63. The scooping member 62 has a recessed part 79 recessed toward the upstream side of the rotation direction at a position where the rotation locus of the scooping member overlaps with a light transmission window 38 in an opposite direction, so that a toner T can be stored and held in the recessed part 79. Therefore, even when the toner T is brought to a position facing the light transmission window 38 by the agitating member 63 during rotation of the agitating member 63, the toner T is scooped by the recessed part 79 of the scooping member 62 and is brought to the opposite side of the light transmission window 38 with respect to the center axis line 66 of the rotating shaft 61.

Description

  The present invention relates to an image forming apparatus such as a laser printer and a cartridge attached to the image forming apparatus.

  In an example of an image forming apparatus such as a laser printer, a photosensitive drum and a developing device are provided. In the case of the developing device, a toner storage chamber and a developing chamber that are in communication with each other are formed. For example, an agitator made of PET (polyethylene terephthalate) is rotatably provided in the toner storage chamber. A developing roller is rotatably provided in the developing chamber. A part of the developing roller is exposed outside the developing chamber and is in contact with the surface of the photosensitive drum.

  The toner in the toner chamber is supplied from the toner chamber to the developing chamber while being stirred in the toner chamber by the rotation of the agitator. The toner supplied into the developing chamber is supplied to the surface of the photosensitive drum by the developing roller. On the other hand, an electrostatic latent image is formed on the surface of the photosensitive drum. Then, the electrostatic latent image is developed into a toner image with toner, and the toner image is transferred to a sheet, thereby forming an image on the sheet.

  For this reason, toner is consumed as the image is formed on the paper. When the toner in the developing device runs out, an image cannot be formed on the paper, so that it is necessary to replace the developing device or supply toner to the toner storage chamber.

  Therefore, the image forming apparatus is provided with a configuration for detecting a state (empty state) in which the remaining amount of toner in the toner storage chamber is low. That is, a pair of light transmission windows are formed on the side wall of the toner storage chamber at positions facing each other in a direction parallel to the rotational axis of the agitator. A light emitting element is disposed outside the developing device at a position facing one light transmission window, and a light receiving element is disposed at a position facing the other light transmission window. In a state where the toner is sufficiently present in the toner storage chamber, the light transmission window is covered with the toner, so that light from the light emitting element does not reach the light receiving element. When the remaining amount of toner in the toner storage chamber decreases, the light transmission window is not covered with toner, and light from the light emitting element reaches the light receiving element. Therefore, it is possible to detect whether or not the remaining amount of toner in the toner storage chamber has decreased based on whether or not the light from the light emitting element reaches the light receiving element.

Japanese Patent Laid-Open No. 2001-5276

  However, although the amount of toner remaining in the toner storage chamber is small, the toner sent to the position facing the light transmission window by the agitator stays at that position for a long time, and the light from the light emitting element does not reach the light receiving element. Sometimes. When such a state occurs, detection of a decrease in the remaining amount of toner in the toner storage chamber is delayed.

  An object of the present invention is to provide a cartridge and an image forming apparatus including the cartridge that can accurately detect that the remaining amount of the developer in the developer accommodating chamber has decreased.

  To achieve the above object, according to a first aspect of the present invention, a cartridge includes a pair of side walls opposed to each other with a space therebetween and a developer containing chamber defined by a peripheral wall provided between the pair of side walls. A housing is provided in the developer accommodating chamber, and slidably rubs against at least a part of the peripheral wall by rotation about a rotation axis extending in the opposing direction of the pair of side walls. An agitating member for agitating the contained developer; a pair of light transmitting portions provided on each of the side walls, facing each other in the facing direction and transmitting light traveling in the facing direction; and the developer containing It is provided in the room so as to be rotatable in the same direction as the rotation direction of the stirring member around the rotation axis, and the developer can be accommodated and held at a position where the rotation locus overlaps with the light transmission portion. So that the rotation It is characterized in that it comprises a scoop member having a recess which is recessed toward the upstream side of the direction.

  According to a second aspect of the present invention, in the image forming apparatus, the cartridge according to any one of claims 1 to 6, a main body casing that accommodates the cartridge, and the pair of the main casings are provided in the main body casing. A sensor that receives light transmitted through the light transmitting portion and outputs a signal, and a developer amount that detects the amount of developer contained in the developer containing chamber based on a signal output from the sensor And a detector.

  According to the first and second aspects of the invention, the cartridge housing has a pair of side walls facing each other with a space therebetween and a developer containing chamber defined by a peripheral wall provided between the pair of side walls. ing. A stirring member is provided in the developer accommodating chamber. The agitating member slidably rubs against at least a part of the peripheral wall by rotation about a rotation axis extending in the opposing direction of the pair of side walls, and agitates the developer accommodated in the developer accommodating chamber.

  Each side wall of the housing is provided with a pair of light transmitting portions that face each other in the facing direction and are capable of transmitting light traveling in the facing direction. For this reason, a sensor that receives light transmitted through the pair of light transmitting portions and outputs a signal is provided, and the amount of developer stored in the developer storage chamber is detected based on a signal output from the sensor. can do.

  In the developer storage chamber, a scooping member is provided so as to be rotatable in the same direction as the rotation direction of the stirring member around a rotation axis common to the stirring member. The scooping member has a concave portion that is recessed toward the upstream side in the rotational direction so that the developer can be accommodated and held at a position where the rotation trajectory overlaps with the light transmission portion. Therefore, even when the developer is sent to a position facing the light transmission portion by the stirring member during rotation of the stirring member, the developer is scooped up by the concave portion of the scooping member, and the light transmission portion with respect to the rotation axis. And sent to the other side. Thereby, the dispersion of the developer in the developer storage chamber is made uniform. Therefore, it is possible to accurately detect that the remaining amount of the developer in the developer accommodating chamber has decreased based on the light transmitted through the light transmitting portion (signal output from the sensor).

FIG. 1 is a sectional view of a laser printer according to an embodiment of the present invention. FIG. 2 is a plan view of the process cartridge (process cartridge according to the first embodiment) shown in FIG. FIG. 3A is a cross-sectional view of the process cartridge taken along the cutting line AA shown in FIG. 2 and shows a state in which a part of the scooping member faces the light transmission window. FIG. 3B is a cross-sectional view of the process cartridge taken along the cutting line AA shown in FIG. 2 and shows a state immediately after the scooping member has passed through the position facing the light transmission window. 3C is a cross-sectional view of the process cartridge taken along the cutting line AA shown in FIG. 2 and shows a state in which the scooping member is located on the opposite side of the light transmission window with respect to the rotation axis. FIG. 4 is a perspective view of the agitator shown in FIG. 3A. FIG. 5A is a cross-sectional view of the process cartridge according to the second embodiment, showing a state in which a part of the scooping member faces the light transmission window. FIG. 5B is a cross-sectional view of the process cartridge according to the second embodiment, showing a state immediately after the scooping member has passed through a position facing the light transmission window. FIG. 5C is a cross-sectional view of the process cartridge according to the second embodiment, showing a state in which the scooping member is located on the opposite side of the light transmission window with respect to the rotation axis. FIG. 6 is a perspective view of the agitator shown in FIG. 5A.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
<First Embodiment>
1. Laser Printer As shown in FIG. 1, a laser printer 1 as an example of an image forming apparatus includes a main body casing 2. A front cover 3 is provided on the front surface of the main casing 2 so as to be openable and closable. A process cartridge 4 is arranged at a position slightly above the center in the main body casing 2. The process cartridge 4 can be attached / detached to / from the main body casing 2 with the front cover 3 opened.

  The side on which the front cover 3 is provided (the right side in FIG. 1) is defined as the front side (front side) of the laser printer 1, and the laser printer 1 is defined in the vertical and horizontal directions when viewed from the front side. Further, the process cartridge 4 is defined in the front, rear, upper, lower, left and right directions in a state where it is mounted on the main casing 2.

  The process cartridge 4 includes a drum cartridge 5 and a developing cartridge 6 as an example of a cartridge that can be attached to and detached from the drum cartridge 5.

  The drum cartridge 5 includes a cartridge frame 7. A photosensitive drum 8 is rotatably held at the rear end of the cartridge frame 7. The cartridge frame 7 holds a charger 9 and a transfer roller 10. The charger 9 and the transfer roller 10 are disposed above and below the photosensitive drum 8, respectively.

  The developing cartridge 6 is mounted on a portion of the cartridge frame 7 on the front side of the photosensitive drum 8. The developing cartridge 6 includes a box-shaped housing 11. Inside the housing 11, a toner storage chamber 12 and a development chamber 13 as an example of a developer storage chamber are formed adjacent to each other in the front-rear direction. The toner storage chamber 12 and the development chamber 13 are in communication with each other. The developing cartridge 6 is provided with an agitator 14.

  A rectangular opening 15 that is long in the left-right direction is formed at the rear end of the housing 11, and the inside of the developing chamber 13 communicates with the outside of the housing 11 through the opening 15. A developing roller 16 and a supply roller 17 are provided in the developing chamber 13.

  The developing roller 16 is disposed so that a part of the peripheral surface thereof is exposed to the outside through the opening 15. Then, in a state where the developing cartridge 6 is mounted on the drum cartridge 5, a portion exposed from the opening 15 in the developing roller 16 comes into contact with the photosensitive drum 8 from the front upper side.

  The supply roller 17 is disposed so as to contact the developing roller 16 from the front lower side.

  The toner T (see FIG. 3A) is supplied to the developing roller 16 by the supply roller 17. The toner T supplied to the developing roller 16 is carried on the developing roller 16 as a thin layer having a constant thickness.

  In the main casing 2, an exposure unit 18 provided with a laser or the like is disposed above the process cartridge 4. A laser beam based on the image data is emitted from the exposure unit 18.

  At the time of image formation, the photosensitive drum 8 is rotated at a constant speed clockwise as viewed from the left side. Along with the rotation of the photosensitive drum 8, the surface of the photosensitive drum 8 is uniformly charged by the discharge from the charger 9 and then exposed by the laser beam from the exposure unit 18. By this exposure, electric charges are selectively removed from the surface of the photosensitive drum 8, and an electrostatic latent image is formed on the surface of the photosensitive drum 8. When the electrostatic latent image faces the developing roller 18 by the rotation of the photosensitive drum 8, the toner T is supplied from the developing roller 18 to the electrostatic latent image. As a result, a toner image is carried on the surface of the photosensitive drum 8.

  A paper feed cassette 19 that stores paper P is disposed at the bottom of the main casing 2. In the main casing 2, a sheet conveyance path 20 having an S-shape in side view is formed. The sheet conveyance path 20 reaches from the front end of the sheet feeding cassette 19 to the sheet discharge tray 21 formed on the upper surface of the main casing 2 via the photosensitive drum 8 and the transfer roller 10. The paper P stored in the paper feed cassette 19 is sent out one by one from the paper feed cassette 19 by various rollers, and is transported toward the paper discharge tray 21 through the paper transport path 20.

During the conveyance of the sheet P, when the sheet P passes between the photosensitive drum 8 and the transfer roller 10, the toner image on the surface of the photosensitive drum 8 is applied to the sheet P by the electrical action of the transfer roller 10. Transcribed. The sheet P on which the toner image is transferred is sent to the fixing device 22. In the fixing device 22, the toner image is fixed on the paper P as an image by heating and pressing. The paper P on which the image is thus formed is discharged onto the paper discharge tray 21.
2. Housing of Developer Cartridge The housing 11 of the developer cartridge 6 includes a pair of side walls 31 and 32 as shown in FIG. The side walls 31 and 32 are plate-shaped that face each other in the left-right direction and extend in the front-rear direction.

  Moreover, the housing | casing 11 is provided with the upper wall 33 as an example of the surrounding wall constructed between each upper end part of the side walls 31 and 32, as FIG. 2, FIG. 3A-3C shows. The upper wall 33 has a plate shape extending in the front-rear direction and the left-right direction.

  Furthermore, the housing | casing 11 is provided with the lower wall 34 constructed between each lower end part of the side walls 31 and 32, as FIG. 3A-3C shows. A V-shaped partition portion 35 that is pointed upward is formed in the middle portion of the lower wall 34 in the front-rear direction. The front side portion 36 of the lower wall 34 in front of the partition portion 35 is an example of a peripheral wall. The upper wall 33 extends upward from the front end of the circular arc portion and a semicircular arc-shaped cross section that is convexly curved downward. And a connecting portion connected to the front end of the. Further, the rear portion 37 on the lower wall 34 behind the partition portion 35 has a plate shape extending rearward from the partition portion 35. The toner storage chamber 12 is partitioned by the side walls 31, 32, the upper wall 33, and the front portion 36 of the lower wall 34, and the developing chamber 13 is defined by the side walls 31, 32, the upper wall 33, and the rear portion 37 of the lower wall 34. Is partitioned. The toner storage chamber 12 and the developing chamber 13 communicate with each other via the upper wall 33 and the partition portion 35.

Each of the side walls 31 and 32 is formed with a light transmission window 38 as an example of a light transmission portion. The light transmission window 38 is formed by fitting a circular plate made of a transparent resin into a circular hole formed through the side walls 31 and 32. The light transmission windows 38 of the side walls 31 and 32 are arranged at positions spaced rearward from the partition portion 35 of the lower wall 34, and form a pair and face each other in the left-right direction.
3. Empty Sensor As shown in FIG. 2, an empty sensor 43 as an example of a sensor composed of a pair of a light emitting element 41 and a light receiving element 42 is provided in the main body casing 2. The light emitting element 41 and the light receiving element 42 are disposed so as to face each other in the left-right direction across the position where the developing cartridge 6 is disposed in the main casing 2. In a state where the process cartridge 4 (developing cartridge 6) is mounted in the main casing 2, the light emitting element 41 faces the light transmission window 38 of the right side wall 32 from the right side (outside), and the light receiving element 42. Is opposed to the light transmission window 38 of the left side wall 31 from the left side (outside). That is, with the process cartridge 4 mounted in the main casing 2, the toner storage chamber 12 of the developing cartridge 6 and a pair of light transmission windows 38 are disposed on the optical path from the light emitting element 41 to the light receiving element 42. .
4). Toner amount detection unit The laser printer 1 also includes a toner amount as an example of a developer amount detection unit for detecting the amount (remaining amount) of toner T stored in the toner storage chamber 12 of the developing cartridge 6. A detection unit 51 is provided. For example, the toner amount detection unit 51 is incorporated in a control unit for controlling each unit of the laser printer 1 as a part of its function. The control unit is composed of a microcomputer.

A light emitting element 41 and a light receiving element 42 are connected to the toner amount detection unit 51. The toner amount detection unit 51 controls light emission of the light emitting element 41. For example, the light receiving element 42 outputs a high-level signal during a period in which light from the light emitting element 41 is not received (during light reception), and during a period in which light from the light emitting element 41 is received (during light reception). Outputs a low level signal. The toner amount detection unit 51 controls the light emission of the light emitting element 41 and detects the amount of toner T stored in the toner storage chamber 12 based on a signal output from the light receiving element 42 during the control.
5). As shown in FIG. 4, the agitator 14 includes a rotation shaft 61 extending in the left-right direction, a shovel-like scrubbing member 62 provided integrally with the rotation shaft 61, and a stirring member 63 attached to the scooping member 62. And a wiper holding member 64 provided integrally with the rotary shaft 61, and a wiper 65 held by the wiper holding member 64.

  The rotating shaft 61 is constructed between the side walls 31 and 32. The left end portion and the right end portion of the rotary shaft 61 are rotatably supported by the side walls 31 and 32, respectively. The central axis 66 of the rotation shaft 61 is an example of the rotation axis. The left end portion of the rotating shaft 61 passes through the side wall 31, and a gear (not shown) is provided in a portion that protrudes outward (left side) from the side wall 31 so as not to be relatively rotatable. When the driving force is input to the gear, the rotating shaft 61 rotates clockwise as viewed from the left side.

  The scooping member 62 is housed in the toner housing chamber 12 and is provided in non-contact with the side walls 31, 32, the upper wall 33 and the lower wall 34. The scooping member 62 extends long in the left-right direction. As shown in FIGS. 3A to 3C, the scooping member 62 includes a connecting portion 71, a first wall 72, a second wall 73, a third wall 74, a light shielding wall 75 and a stirring member attaching portion 76. Integrated.

  The connecting portion 71 extends in the radial direction of the rotating shaft 61 from the peripheral surface of the rotating shaft 61 and is L-shaped in a side view bent at a right angle upstream of the rotating direction of the rotating shaft 61 (hereinafter simply referred to as “rotating direction”). It has a shape.

  The first wall 72 has a plate shape extending in the direction away from the rotation shaft 61 in parallel with the radial direction of the rotation shaft 61 from the entire width of the distal end portion of the connecting portion 71.

  The second wall 73 has a substantially plate shape extending from the entire width of the end portion of the first wall 72 on the connecting portion 71 side (rotating shaft 61 side) to the upstream side in the rotation direction. The second wall 73 is bent slightly in the middle and extends in a direction away from the third wall 74. As a result, the downstream surface of the second wall 73 in the rotational direction has a base end portion orthogonal to the first wall 72, a middle portion bent, and a distal end portion in the rotational direction with respect to the base end portion. Inclined upstream.

  The third wall 74 has a plate shape extending perpendicularly to the first wall 72 from the full width of the end portion of the first wall 72 opposite to the connecting portion 71 to the upstream side in the rotational direction.

  As shown in FIGS. 3A to 3C, the first wall 72, the second wall 73, and the third wall 74 have a concave shape that is open in the direction in which the second wall 73 and the third wall 74 extend from the first wall 72. ing. In other words, the first wall 72, the second wall 73, and the third wall 74 form a recess 79 that is recessed toward the upstream side in the rotation direction of the rotation shaft 61. The length from the first wall 72 to the tip of the second wall 73 is larger than the length from the first wall 72 to the tip of the third wall 74, and the center axis 66 of the rotation shaft 61 and the tip of the second wall 73 are Is longer than the linear distance D2 between the central axis 66 and the third wall 74.

  The light shielding wall 75 has a trapezoidal shape in a side view, and straddles the first wall 72, the second wall 73, and the third wall 74 on both the left and right ends of the scooping member 62. 73 and the third wall 74 are provided so as to block the space surrounded on three sides from the left and right. Further, a plurality of light shielding walls 75 are provided at equal intervals in the left-right direction between the light shielding walls 75 at both left and right ends. The linear distance between the central axis 66 of the rotation shaft 61 and the central portion of the light shielding wall 75 is substantially equal to the linear distance between the central axis 66 and the light transmission window 38, and the central axis 66 of the light shielding wall 75 is the center. The rotating locus that overlaps the light transmission window 38 in the left-right direction.

  The stirring member mounting portion 76 is provided so as to protrude from the entire width of the end portion of the first wall 72 opposite to the connecting portion 71 side to the upstream side in the rotational direction, that is, the opposite side to the third wall 74. The stirring member attaching portion 76 has a right-angled triangular shape in a side view having an orthogonal surface 77 orthogonal to the first wall 72 and an inclined surface 78 straddling the leading edge of the orthogonal surface 77 and the edge of the first wall 72. Yes.

  The stirring member 63 is made of a flexible film such as a resin film, and has a rectangular shape having substantially the same width in the left-right direction as the stirring member mounting portion 76. One end portion of the stirring member 63 extending in the longitudinal direction (left-right direction) is attached to the inclined surface 78 of the stirring member mounting portion 76, and the other end portion is on the third wall 74 side with respect to the first wall 72. Is arranged. The other end of the stirring member 63 rubs against the front portion 36 of the lower wall 34 when the agitator 14 rotates.

  The wiper holding member 64 is provided on a portion of the rotating shaft 61 that protrudes from the left and right sides of the scooping member 62. Each wiper holding member 64 extends substantially in parallel to the second wall 73 of the scooping member 62 with a space upstream from the scooping member 62 in the rotational direction. The linear distance between the central axis 66 of the rotation shaft 61 and the tip of each wiper holding member 64 is substantially equal to the linear distance D1 between the central axis 66 and the tip of the second wall 73.

The wiper 65 is held at the tip of each wiper holding member 64 so as to be along a plane parallel to the rotation shaft 61. The wiper 65 is made of an elastic material such as rubber and has a substantially rectangular plate shape. The left end portion and the right end portion of the left and right wipers 65 protrude from the wiper holding member 64 and rub against the light transmission window 38 when the agitator 14 rotates.
6). Toner Amount Detection During the operation for forming an image on the paper P, as shown in FIGS. 3A to 3C, the rotating shaft 61 of the agitator 14 is rotated clockwise at a constant speed as viewed from the left side. As the rotating shaft 61 rotates, the stirring member 63, the scooping member 62, and the wiper 65 rotate, and the stirring member 63, the scooping member 62, and the wiper 65 are light transmission windows provided on the side walls 31, 32 of the developing cartridge 6. 38 is repeatedly passed in this order in a position that opposes the left and right direction of 38 (hereinafter referred to as “a position that opposes the light transmission window 38”). Further, light is emitted from the light emitting element 41.

  The toner T in the toner storage chamber 12 of the developing cartridge 6 is pushed downstream in the rotation direction by the stirring member 63. As a result, the toner T is agitated in the toner storage chamber 12, and the toner T in the toner storage chamber 12 is supplied to the developing chamber 13 through the space between the upper wall 33 and the partition portion 35.

  Immediately after the stirring member 63 passes through the position facing the light transmission window 38, the water level of the toner T varies greatly in the vicinity of the light transmission window 38. Therefore, the light entering the toner storage chamber 12 from the light emitting element 41 through the light transmission window 38 is blocked by the toner T, or the light passes through the toner storage chamber 12 and is received by the light receiving element 42. . Therefore, immediately after the stirring member 63 passes through the position facing the light transmission window 38, the amount of toner T in the toner storage chamber 12 (constant in the toner storage chamber 12 is constant) based on the signal output from the light receiving element 42. It is not possible to accurately detect whether or not the amount of toner T is contained.

  Therefore, the light blocking wall 75 is provided on the scooping member 62, and the light blocking wall 75 faces the light transmitting window 38 immediately after the stirring member 63 passes through the position facing the light transmitting window 38. The light from the light emitting element 41 is blocked by the light blocking wall 75 until the light blocking wall 75 has passed through the position. As a result, light from the light emitting element 41 is not received by the light receiving element 42 and at least a high level signal is received from the light receiving element 42 within the time required for the light shielding wall 75 to pass through the position facing the light transmission window 38. Continue to output.

  When the light shielding wall 75 finishes passing through the position facing the light transmission window 38, the water level of the toner T is stable in the vicinity of the light transmission window 38 (the fluctuation of the water level is subsided). When a sufficient amount of toner T above a certain amount (the amount of water positioned above the upper end of the light transmission window 38 when the water surface of the toner T is horizontal) is stored in the toner storage chamber 12 After the light shielding wall 75 has passed through the position facing the light transmission window 38, the light transmission window 38 is covered with the toner T. Therefore, light from the light emitting element 41 is blocked by the toner T and does not reach the light receiving element 42. Therefore, a high level signal is output from the light receiving element 42 even after the light shielding wall 75 has passed through the position facing the light transmission window 38. On the other hand, when the amount of toner T stored in the toner storage chamber 12 is less than a certain amount, when the light shielding wall 75 finishes passing through the position facing the light transmission window 38, the light emitting element 41 changes to the light receiving element 42. Only the light transmission window 38 exists on the optical path to reach, and the light from the light emitting element 41 is received by the light receiving element 42. Therefore, a low level signal is output from the light receiving element 42 after the light shielding wall 75 has passed through the position facing the light transmission window 38.

  Therefore, when a high level signal continues to be output from the light receiving element 42 during a predetermined period after the light shielding wall 75 (the scooping member 62) has passed through the position facing the light transmission window 38, the toner amount detection unit 51, it is detected that a certain amount or more of toner T is stored in the toner storage chamber 12. On the other hand, when a low level signal is output from the light receiving element 42 during the predetermined period, the toner amount detection unit 51 detects that the amount of toner T stored in the toner storage chamber 12 has become less than a certain amount. Is done.

  However, even after the stirring member 63 has passed through the position facing the light transmission window 38, the toner T sent to the position facing the light transmission window 38 by the stirring member 63 continues to stay at that position, and the toner The water level of T is locally high at a position facing the light transmission window 38, and the water level of the toner T may be stabilized in a state where the toner T covers the light transmission window 38. In this case, although the amount of toner T in the toner storage chamber 12 is less than a certain amount, a high level signal continues to be output from the light receiving element 42, and the toner amount detection unit 51 causes the toner storage chamber 12 to be output. There is a possibility that it is not detected that the amount of toner T accommodated in the toner container is less than a certain amount.

Therefore, the agitator 14 is provided with a scooping member 62. After the stirring member 63 passes through the position facing the light transmission window 38, the light from the light emitting element 41 is blocked by the light shielding wall 75, and the position facing the light transmission window 38 by the concave portion 79 of the scooping member 62. The existing toner is scooped out. The scooping member 62 also collects the toner T splashed up by its elasticity when the tip of the stirring member 63 moves away from the partition portion 35. Then, with the rotation of the agitator 14, the toner T scooped up by the scooping member 62 (concave portion 79) is sent together with the scooping member 62 to the opposite side of the light transmission window 38 with respect to the rotating shaft 61. Thereby, the dispersion of the toner T in the toner storage chamber 12 is made uniform, and the water level of the toner T is stabilized in a state where the water surface of the toner T is almost horizontal.
7). Function and Effect (1) Function and Effect 1
As described above, the housing of the developing cartridge 6 includes the pair of side walls 31 and 32 facing each other with a space therebetween, and the front side portions of the upper wall 33 and the lower wall 34 provided between the pair of side walls 31 and 32. The toner storage chamber 12 is partitioned by 36. A stirring member 63 is provided in the toner storage chamber 12. The agitating member 63 slidably rubs against the front portion 36 of the lower wall 34 by the rotation about the central axis 66 of the rotating shaft 61 extending in the opposing direction of the pair of side walls 31 and 32 and enters the toner storage chamber 12. The contained toner T is stirred.

  Each of the side walls 31 and 32 of the housing is provided with a pair of light transmission windows 38 that face each other in the facing direction and can transmit light traveling in the facing direction. Therefore, an empty sensor 43 that receives light transmitted through the pair of light transmission windows 38 and outputs a signal is provided, and is stored in the toner storage chamber 12 based on a signal output from the empty sensor 43. The amount of toner T can be detected.

In the toner storage chamber 12, a scooping member 62 is provided so as to be rotatable in the same direction as the rotation direction of the stirring member 63 around the central axis 66 of the rotation shaft 61 common to the stirring member 63. The scooping member 62 has a recess 79 that is recessed toward the upstream side in the rotational direction so that the toner T can be accommodated and held at a position where the rotational locus overlaps with the light transmission window 38. Therefore, even when the stirring member 63 rotates, even if the toner T is sent to the position facing the light transmission window 38 by the stirring member 63, the toner T is scooped up by the concave portion 79 of the scooping member 62, and the rotating shaft 61. Is sent to the opposite side of the light transmission window 38 with respect to the central axis 66. Thereby, the dispersion of the toner T in the toner storage chamber 12 is made uniform. Therefore, it is possible to accurately detect that the remaining amount of the toner T in the toner storage chamber 12 has decreased based on the light transmitted through the light transmission window 38 (signal output from the empty sensor 43).
(2) Action effect 2
The scooping member 62 is provided in non-contact with the upper wall 33 and the lower wall 34. Therefore, the rotation of the scooping member 62 can be prevented from being inhibited by the upper wall 33 and the lower wall 34.
(3) Effect 3
The scooping member 62 is provided on the upstream side in the moving direction of the stirring member 63 and scooping member 62 in the light transmission window 38 with respect to the stirring member 63. As a result, the toner T that has risen in the vicinity of the light transmission window 38 due to the stirring of the stirring member 63 can be scooped up by the recess 79 of the scooping member 62, so that the light transmission window 38 is covered by the raised toner T. It can prevent well.
(4) Action effect 4
The scooping member 62 includes a first wall 72 extending in parallel with a radial direction of rotation about the central axis 66 of the rotation shaft 61, and a first wall 72 from the end on the central axis 66 side of the rotation shaft 61 in the first wall 72. A second wall 73 extending in a direction intersecting with the second wall 73, and a third wall 74 extending from an end of the first wall 72 on the peripheral wall side and facing the second wall 73 with a space therebetween. A recess 79 is formed by the first wall 72, the second wall 73, and the third wall 74.

The linear distance D1 between the central axis 66 of the rotating shaft 61 and the tip of the second wall 73 is longer than the linear distance D2 between the central axis 66 of the rotating shaft 61 and the third wall 74. Therefore, the toner T can be scooped up favorably by the second wall 73.
(5) Action effect 5
The second wall 73 extends away from the third wall 74 toward the distal end side. That is, the second wall 73 is inclined with respect to the third wall 74. Therefore, even if a centrifugal force due to the rotation of the scooping member 62 acts on the toner T scooped up by the second wall 73, the toner T flows down from the second wall 73 along the inclination. Therefore, the toner T can be prevented from staying on the second wall 73.
(6) Action effect 6
Immediately after the stirring member 63 passes through the position facing the light transmission window 38, the water level of the toner T varies greatly in the vicinity of the light transmission window 38. For this reason, light entering the toner storage chamber 12 through the light transmission window 38 is blocked by the toner T, or the light passes through the toner storage chamber 12. Therefore, immediately after the stirring member 63 passes through the position facing the light transmission window 38, the amount of toner T in the toner storage chamber 12 is accurately determined based on the signal output from the empty sensor 43 (light receiving element 42). It cannot be detected.

Therefore, the scooping member 62 is provided with a light blocking wall 75 for blocking light transmitted through the light transmitting window 38. The light shielding wall 75 extends in parallel with the side walls 31 and 32. During the period when the water level of the toner T at the position facing the light transmission window 38 is unstable, the light shielding wall 75 faces the light transmission window 38, thereby causing a change in the water level of the toner T. It is possible to prevent erroneous detection of the amount of toner T.
(7) Action effect 7
The toner amount detection unit 51 is based on a signal output from the empty sensor 43 during a predetermined period after the scooping member 62 passes the position facing the light transmission window 38 when the stirring member 63 and scooping member 62 rotate. The amount of toner T is detected. Thus, the amount of toner T is detected based on the signal output from the empty sensor 43 after the dispersion of the toner T in the toner storage chamber 12 is made uniform. As a result, the amount of toner T can be detected accurately.
Second Embodiment
1. Agitator FIGS. 5A to 5C show a process cartridge 104 according to a second embodiment of the present invention.

  In place of the process cartridge 4 shown in FIGS. 3A to 3C, the process cartridge 104 can be attached / detached to / from the main body casing 2 (see FIG. 1). The process cartridge 104 has the same configuration as the process cartridge 4 except for the agitator 114.

  Hereinafter, only the configuration of the agitator 114 will be described, and description of the configuration common to the process cartridge 4 and the process cartridge 104 will be omitted. 5A to 5C, the same reference numerals as those of the respective parts are given to the parts common to the respective parts shown in FIGS. 3A to 3C.

  As shown in FIG. 6, the agitator 114 includes a rotating shaft 161 extending in the left-right direction, a scooping member 162 provided integrally with the rotating shaft 161, a stirring member 163 attached to the scooping member 162, and a rotating shaft 161. And a wiper holding member 164 provided integrally with the wiper holding member 164 and a wiper 165 held by the wiper holding member 164.

  The rotating shaft 161 is constructed between the side walls 31 and 32. The left end portion and the right end portion of the rotating shaft 161 are rotatably supported by the side walls 31 and 32, respectively. The central axis 66 of the rotation shaft 161 is an example of the rotation axis. The left end portion of the rotating shaft 161 passes through the side wall 31, and a gear (not shown) is provided at a portion protruding outward (left side) from the side wall 31 so as not to be relatively rotatable. Then, when the driving force is input to the gear, the rotating shaft 161 rotates clockwise as viewed from the left side.

  The scooping member 162 is accommodated in the toner accommodating chamber 12 and is provided in non-contact with the side walls 31, 32, the upper wall 33 and the lower wall 34. The scooping member 162 extends long in the left-right direction, and integrally includes a connecting portion 171, a first wall 172, a second wall 173, a third wall 174, and a light shielding wall 175, as shown in FIGS. .

  The connecting portion 171 extends in the radial direction of the rotating shaft 161 from the peripheral surface of the rotating shaft 161 and is bent L at a right angle downstream of the rotating direction of the rotating shaft 161 (hereinafter simply referred to as “rotating direction”). It has a shape.

  The first wall 172 has a plate shape extending in the direction away from the rotation shaft 161 in parallel with the radial direction of the rotation shaft 161 from the entire width of the distal end portion of the connecting portion 171.

  The second wall 173 has a substantially plate shape extending from the entire width of the end portion of the first wall 172 opposite to the connecting portion 171 side (rotation shaft 161 side) to the downstream side in the rotation direction. The second wall 173 is bent slightly in the middle and extends in a direction away from the third wall 174. As shown in FIGS. 5A to 5C, the upstream surface of the second wall 173 in the rotation direction is inclined so as to approach the third wall 174 as the proximal end approaches the distal end, and the middle portion is bent. Thus, the tip portion extends in a direction away from the third wall 174.

  The third wall 174 has a plate shape extending perpendicularly to the first wall 172 from the full width of the end portion of the first wall 172 on the connecting portion 171 side to the upstream side in the rotation direction.

  The first wall 172, the second wall 173, and the third wall 174 have a concave shape that is open in the direction in which the second wall 173 and the third wall 174 extend from the first wall 172. In other words, the first wall 172, the second wall 173, and the third wall 174 form a recess 179 that is recessed toward the upstream side in the rotational direction of the rotating shaft 161. The length from the first wall 172 to the tip of the second wall 173 is larger than the length from the first wall 172 to the tip of the third wall 174, and the center axis 166 of the rotating shaft 161 and the tip of the second wall 173 Is longer than the linear distance D4 between the central axis 166 and the third wall 174.

  The light shielding wall 175 has a trapezoidal shape when viewed from the side, and straddles the first wall 172, the second wall 173, and the third wall 174 on the left and right ends of the scooping member 162. 173 and the third wall 174 are provided so as to close the space surrounded by the three sides from the left and right. A plurality of light shielding walls 175 are provided at equal intervals in the left-right direction between the light shielding walls 175 at both left and right ends. The linear distance between the central axis 166 of the rotation shaft 161 and the central portion of the light shielding wall 175 is substantially equal to the linear distance between the central axis 166 and the light transmission window 38, and the central axis 166 of the light shielding wall 175 is the center. The rotating locus that overlaps the light transmission window 38 in the left-right direction.

  The stirring member 163 is made of a flexible film such as a resin film, and has a rectangular shape that is substantially the same in width in the left-right direction as the second wall 173. One end portion of the stirring member 163 extending in the longitudinal direction (left-right direction) is attached to the proximal end portion of the upstream surface of the second wall 173 in the rotational direction, and the other end portion is located downstream in the rotational direction. It can be extended. The other end of the stirring member 163 rubs against the front portion 36 of the lower wall 34 when the agitator 114 rotates.

  The wiper holding member 164 is provided on a portion of the rotating shaft 161 that protrudes from the left and right sides of the scooping member 162. Each wiper holding member 164 extends in the radial direction of the rotating shaft 161 at a position overlapping the connecting portion 171 of the scooping member 162 in the left-right direction. The linear distance between the central axis 166 of the rotating shaft 161 and the tip of each wiper holding member 164 is substantially equal to the linear distance D3 between the central axis 166 and the tip of the second wall 173.

The wiper 165 is held at the tip of each wiper holding member 164 along a plane parallel to the rotation shaft 161. The wiper 165 is made of an elastic material such as rubber and has a substantially rectangular plate shape. The left and right end portions of the left and right wipers 165 protrude from the wiper holding member 164 and rub against the light transmission window 38 when the agitator 14 rotates.
2. Effects During the operation for forming an image on the paper P, as shown in FIGS. 5A to 5C, the rotating shaft 161 of the agitator 114 is rotated clockwise at a constant speed as viewed from the left side. As the rotary shaft 161 rotates, the scooping member 162, the stirring member 163, and the wiper 165 rotate, and the scooping member 162, the stirring member 163, and the wiper 165 repeatedly pass through the positions facing the light transmission window 38 in this order. Further, light is emitted from the light emitting element 41.

  The toner T in the toner storage chamber 12 of the developing cartridge 6 is pushed downstream in the rotation direction by the stirring member 63. As a result, the toner T is agitated in the toner storage chamber 12, and the toner T in the toner storage chamber 12 is supplied to the developing chamber 13 through the space between the upper wall 33 and the partition portion 35.

  Even after the stirring member 163 has passed through the position facing the light transmission window 38, the toner T sent to the position facing the light transmission window 38 by the stirring member 163 continues to stay at that position, and the toner T The water level locally increases at a position facing the light transmission window 38, and the water level of the toner T may be stabilized in a state where the toner T covers the light transmission window 38.

  Therefore, the agitator 114 is provided with a scooping member 162, and the toner T present at a position facing the light transmission window 38 is scooped up by the concave portion 179 of the scooping member 162. As the agitator 114 rotates, the toner T scooped up by the scooping member 162 (concave portion 179) is sent to the opposite side of the light transmission window 38 with respect to the rotating shaft 161 together with the scooping member 162. Thereby, the dispersion of the toner T in the toner storage chamber 12 is made uniform, and the water surface of the toner T becomes almost horizontal.

Therefore, even if the process cartridge 104 shown in FIGS. 5A to 5C is employed instead of the process cartridge 4 shown in FIGS. 3A to 3C, the toner amount in the toner storage chamber 12 can be accurately detected.
<Modification>
The present invention can be applied not only to a monochrome laser printer but also to a color laser printer.

  In addition, various design changes can be made to the above-described embodiments within the scope of the matters described in the claims.

DESCRIPTION OF SYMBOLS 1 Laser printer 2 Main body casing 6 Developing cartridge 11 Housing | casing 12 Toner storage chamber 14 Agitator 31 Side wall 32 Side wall 33 Upper wall 34 Lower wall 36 Front part 38 Light transmission window 43 Empty sensor 51 Toner amount detection part 61 Rotating shaft 62 Scooping member 63 Stirring member 66 Central axis 72 First wall 73 Second wall 74 Third wall 75 Light shielding wall 79 Recess 114 Agitator 161 Rotating shaft 162 Scuffing member 163 Stirring member 166 Central axis 172 First wall 173 Second wall 174 Third wall 175 Light shielding Wall 179 Concavity D1 Linear distance D2 Linear distance D3 Linear distance T Toner

Claims (8)

A housing having a developer storage chamber defined by a pair of side walls facing each other with a space therebetween and a peripheral wall provided between the pair of side walls;
Development provided in the developer storage chamber and slidably rubbed against at least a part of the peripheral wall by rotation about a rotation axis extending in the opposing direction of the pair of side walls and stored in the developer storage chamber A stirring member for stirring the agent;
A pair of light transmitting portions provided on each of the side walls, facing each other in the facing direction and capable of transmitting light traveling in the facing direction;
The developer accommodating chamber is provided so as to be rotatable in the same direction as the rotation direction of the stirring member around the rotation axis, and the developer is accommodated at a position where the rotation locus overlaps with the light transmission portion. And a scooping member having a recess recessed toward the upstream side in the rotational direction so that the cartridge can be held.   The cartridge according to claim 1, wherein the scooping member is provided in non-contact with the peripheral wall.   The cartridge according to claim 1, wherein the scooping member is provided on the upstream side of the stirrer and the scooping member in the light transmitting portion with respect to the stirrer. The scooping member includes a first wall extending in parallel with a radial direction of rotation about the rotation axis, and a second wall extending in a direction intersecting the first wall from an end of the first wall on the rotation axis side. A wall, and a third wall extending from an end of the first wall on the peripheral wall side and facing the second wall with a space therebetween,
The recess is formed by the first wall, the second wall, and the third wall,
The cartridge according to any one of claims 1 to 3, wherein a linear distance between the rotation axis and the tip of the second wall is longer than a linear distance between the rotation axis and the third wall.   The cartridge according to claim 4, wherein the second wall extends away from the third wall toward the distal end side.   The cartridge according to any one of claims 1 to 5, wherein the scooping member has a light shielding wall that extends in parallel with the side wall and shields light transmitted through the light transmission portion. A cartridge according to any one of claims 1 to 6;
A main body casing for housing the cartridge;
A sensor that is provided in the main body casing, receives light transmitted through the pair of light transmission portions, and outputs a signal;
An image forming apparatus comprising: a developer amount detection unit configured to detect the amount of developer accommodated in the developer accommodating chamber based on a signal output from the sensor.   The developer amount detection unit is based on a signal output from the sensor during a predetermined period after the scooping member passes a position facing the light transmission unit when the stirring member and the scooping member rotate. The image forming apparatus according to claim 7, wherein the amount of the developer is detected.

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