Cartridge and image forming apparatus provided therewith

A cartridge includes: a frame; a rotation body; a driving force transmission unit; and a moving member. The rotation body is provided at the frame and rotatable about its rotation axis relative to the frame. The driving force transmission unit is provided at the frame and transmits an external driving force to the rotation body. The moving member is irreversibly movable to one of a covered position and an exposed position by the external driving force transmitted through the driving force transmission unit. The moving member covers at least a portion of the driving force transmission unit when the moving member is at the covered position. The moving member exposes the driving force transmission unit when the moving member is at the exposed position. The exposed position provides an exposing degree greater than that at the covered position.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from Japanese Patent Application No. 2011-288490 filed Dec. 28, 2011. The entire content of the priority application is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a cartridge to be used in an electro-photographic type image forming apparatus, and to an image forming apparatus provided with the cartridge.

BACKGROUND

As an electro-photographic type image forming apparatus, a printer including a photosensitive body and a developing cartridge configured to supply toner to the photosensitive body is known.

A conventional printer is provided with a detection device for detecting information of the developing cartridge assembled therein, for example, for detecting whether or not the assembled developing cartridge is a brand new cartridge.

Japanese Patent Application Publication No. 2006-267994 proposes a laser printer that detects rotation of a detection gear provided in a developing cartridge using an actuator provided in a main casing and that determines information on the developing cartridge based on a detection result.

In the above laser printer, the detection gear has an abutment protrusion corresponding to the information on the developing cartridge. The detection gear is rotated by a predetermined driving amount after assembly of the developing cartridge to the main casing. At this time, the abutment protrusion abuts on the actuator, allowing the rotation of the detection gear to be detected by the actuator.

SUMMARY

However, in the laser printer described above, the developing cartridge only has the detection gear for allowing the main casing to detect the information on the developing cartridge.

Additionally, substantially the entire part of the detection gear is covered by a gear cover, which lowers visibility of the detection gear from outside the apparatus.

Therefore, a user who does not have knowledge of the new cartridge detection device has a difficulty in determining whether the developing cartridge is a new one or a used one.

It is therefore an object of the present invention to provide a cartridge allowing a user to easily determine whether the cartridge is unused or used and an image forming apparatus provided with the cartridge.

In order to attain the above and other objects, the present invention provides a cartridge including: a frame; a rotation body; a driving force transmission unit; and a moving member. The frame is configured to accommodate therein developing agent. The rotation body has a rotation axis extending in a predetermined direction. The rotation body is provided at the frame and rotatable about the rotation axis relative to the frame. The driving force transmission unit is provided at the frame and configured to transmit an external driving force to the rotation body. The moving member is configured to be irreversibly moved to one of a covered position and an exposed position by the external driving force transmitted through the driving force transmission unit. The moving member covers at least a portion of the driving force transmission unit when the moving member is at the covered position. The moving member exposes the driving force transmission unit when the moving member is at the exposed position. The exposed position provides an exposing degree greater than that at the covered position.

When the moving member is at the covered position, there may be no exposing degree. In other words, when the moving member is at the covered position, the moving member may cover the driving force transmission unit in its entirety.

According to another aspect, the present invention provides an image forming apparatus including: a main casing; and a cartridge. The cartridge is detachable from and attachable to the main casing. The cartridge includes: a frame; a rotation body; a driving force transmission unit; and a moving member. The frame is configured to accommodate therein developing agent. The rotation body has a rotation axis extending in a predetermined direction. The rotation body is provided at the frame and rotatable about the rotation axis relative to the frame. The driving force transmission unit is provided at the frame and configured to transmit a driving force from the main casing to the rotation body. The moving member is configured to be irreversibly moved to one of a covered position and an exposed position by the driving force transmitted through the driving force transmission unit. The moving member covers at least a portion of the driving force transmission unit when the moving member is at the covered position. The moving member exposes the driving force transmission unit when the moving member is at the exposed position. The exposed position provides an exposing degree greater than that at the covered position. The main casing includes: a detection unit; and a judgment unit. The detection unit is configured to detect a movement of the moving member. The judgment unit is configured to judge a condition of the cartridge based on a detection of the detection unit.

The condition of the cartridge judged by the judgment unit in the present invention implies a usage state of the cartridge whether the cartridge is new or used, types of the cartridge, a remaining amount of toner accommodated in the cartridge, and a position of agitation blades, for example.

Further, when the moving member is at the covered position, there may be no exposing degree. That is, when the moving member is at the covered position, the moving member may cover the driving force transmission unit in its entirety.

DETAILED DESCRIPTION

A printer as an image forming apparatus according to one embodiment of the present invention will be described with reference toFIGS. 1 through 13A. Throughout the specification, the terms “upward”, “downward”, “upper”, “lower”, “above”, “below”, “beneath”, “right”, “left”, “front”, “rear” and the like will be used assuming that the image forming apparatus is disposed in an orientation in which it is intended to be used. More specifically, inFIG. 1a left side and a right side are a front side and a rear side, respectively.

1. Overall Structure of Color Printer

Referring toFIG. 1, the printer1is a horizontal direct tandem type color printer. The printer1includes a main casing2having a generally box shape. The main casing2has an upper portion provided with a top cover4which can be opened or closed for opening and closing an opening3. The top cover4has a rear end portion pivotally movably supported to the main casing2. The printer1includes four process cartridges5.

Each process cartridge5is detachable from and attachable to the main casing2. When mounted, the process cartridges5are juxtaposedly arrayed in the frontward/rearward direction at intervals within the main casing2. The four process cartridges5corresponds to four colors different from each other (black, yellow, magenta, and cyan), respectively.

Each process cartridge5includes a drum cartridge6and a developing cartridge7detachable from and attachable to the drum cartridge6.

Each drum cartridge6has a photosensitive drum8. The photosensitive drum8is cylindrical in shape and extends in a lateral direction (rightward/leftward direction), and is rotatably supported to a frame of the drum cartridge6.

Further, the drum cartridge6has a scorotron charger9and an LED unit10. The scorotron charger9is positioned diagonally above and rearward of the photosensitive drum8, and confronts the photosensitive drum8. The LED unit10is positioned above the photosensitive drum8, and confronts the photosensitive drum8.

The developing cartridge7has a developing roller11and a supply roller12adapted to supply toner to the developing roller11.

The developing roller11has a rotation shaft extending in the lateral direction. The developing roller11is rotatably supported in a rear end portion of the developing cartridge7such that each lateral end portion of the rotation shaft is rotatably supported to each side wall33of a cartridge frame31(FIG. 2, described later) of the developing cartridge7. A rear edge of the developing roller11is exposed to an outside through a rear edge of the developing cartridge7and contacts the corresponding photosensitive drum8from an upper front side thereof.

The supply roller12has a rotation shaft extending in the lateral direction. The supply roller12is rotatably supported in the developing cartridge7such that each lateral end portion of the rotation shaft is rotatably supported to each side wall33of the cartridge frame31(described later). The supply roller12is disposed diagonally above and frontward of the developing roller11and in contact therewith.

The developing cartridge7is provided with a layer thickness regulation blade13, a toner chamber14and an agitator15. The layer thickness regulation blade13is adapted to regulate a thickness of a toner layer supplied to the developing roller11. The toner chamber14is positioned above the developing roller11and the supply roller12. The toner chamber14accommodates toner therein.

The agitator15is provided in the toner chamber14for agitating the toner. The agitator15includes an agitator shaft16extending in the lateral direction and agitation blades17extending radially toward an inner circumferential surface of the toner chamber14from the agitator shaft16. The agitator15is adapted to rotate about an axis A (FIG. 3) of the agitator shaft16.

Toner accommodated in the toner chamber14is subjected to tribo-electric charging to have a positive polarity between the supply roller12and the developing roller11. The toner is carried on an outer peripheral surface of the developing roller11in a form of a thin toner layer having a uniform thickness by the layer thickness regulation blade13.

After an outer peripheral surface of the photosensitive drum8is uniformly charged by the scorotron charger9, the surface is exposed to light by the LED unit10based on a predetermined image data to form an electrostatic latent image on the surface. Then, a visible toner image (developing agent image) corresponding to the electrostatic latent image is formed on the outer peripheral surface of the photosensitive drum8by supplying toner carried on the developing roller11to the corresponding photosensitive drum8.

A sheet cassette18is provided at a bottom portion of the main casing2for accommodating sheets P therein in a stacked state. Each sheet P accommodated in the sheet cassette18is passed through a U-shaped passage and is conveyed diagonally upward and rearward to a position between the photosensitive drum8and a conveyor belt19at a prescribed timing by various rollers. Then, each sheet P is conveyed rearward by the conveyer belt19at a position between each photosensitive drum8and each transfer roller20. At this time, the toner image is transferred onto the sheet P.

The sheet P onto which the toner image has been transferred is then conveyed to a fixing unit provided downstream of the conveyer belt19. The fixing unit includes a heat roller21and a pressure roller22. The toner image is thermally fixed to the sheet P when the sheet P passes through the heat roller21and the pressure roller22. The sheet P carrying the toner image is then conveyed through an U-shaped passage frontward and upward, and is discharged onto a discharge tray23provided at the top cover4.

2. Details of Developing Cartridge

As shown inFIGS. 2 and 3, the developing cartridge7includes a cartridge frame31and a drive unit32positioned at a left side of the cartridge frame31.

When referring to the directions in the description of the developing cartridge7, the terms “upward”, “downward”, “upper”, “lower”, “above”, “below”, “beneath”, “right”, “left”, “front”, “rear” and the like will be used assuming that the developing cartridge7is detached from the main casing2and placed on a horizontal plane. Specifically, a side on which the developing roller11is disposed is defined as the rear side, and a side on which the layer thickness regulation blade13is disposed is defined as the upper side.

(1) Cartridge Frame

The cartridge frame31extends in the lateral direction and is generally box shaped, as shown inFIGS. 2 and 3. The cartridge frame31includes the pair of side walls33, a front wall34, a lower wall35and an upper wall36. The pair of side walls33includes a left side wall33L and a right side wall33R.

Each side wall33extends in the frontward/rearward direction and in the vertical direction, and is generally rectangular shaped in a side view. The pair of side walls33is spaced away from each other in the lateral direction. The left side wall33L is formed with an agitator shaft exposure hole37, and a detection window38, as shown inFIG. 3.

The agitator shaft exposure hole37is formed for exposing the agitator shaft16to the outside therethrough. The agitator shaft exposure hole37is positioned at a generally center portion of the left side wall33L in the frontward/rearward direction and is generally circular shaped in a side view. The agitator shaft exposure hole37penetrates through a thickness of the left side wall33L and has a diameter greater than an outer diameter of a left end portion of the agitator shaft16. The left end portion of the agitator shaft16extends through the agitator shaft exposure hole37and protrudes laterally outward from the left side wall33L.

The detection window38is formed in the left side wall33L and positioned adjacent to the agitator shaft exposure hole37. More specifically, the detection window38is positioned diagonally below and frontward of the agitator shaft exposure hole37. The detection window38is a generally circular shaped in a side view. The detection window38is penetrated through a thickness of the left side wall33L. The detection window38is closed by a transparent resin plate.

The agitator shaft16has a right end portion which is rotatably supported to the right side wall33R. Further, the right side wall33R is formed with a detection window (not shown) similar to the detection window38formed in the left side wall33L. The detection window of the right side wall33R is superposed with the detection window38of the left side wall33L when projected in the lateral direction.

The front wall34extends in the lateral direction and is spanned between front end portions of the side walls33. The lower wall35extends in the lateral direction and is spanned between lower end portions of the side walls33such that the lower wall35is connected to a lower end portion of the front wall34. The upper wall36extends in the lateral direction and is spanned between upper end portions of the side walls33such that the upper wall36is connected to an upper end portion of the front wall34.

(2) Drive Unit

As shown inFIGS. 3 and 5, the drive unit32includes a gear train41and a gear cover42for covering the gear train41.

(2-1) Gear Train

The gear train41includes a developing gear43, a supply gear44, a developing coupling45, an idle gear46, and an agitator gear47. The gear train41is adapted to transmit a driving force from the main casing2to the agitator15.

The developing gear43is assembled to a left side of the left side wall33L of the cartridge frame31. The developing gear43is fixedly coupled to a left end portion of the rotation shaft of the developing roller11protruding leftward from the left side wall33L such that relative rotation therebetween is prevented.

The supply gear44is assembled to the left side of the left side wall33L of the cartridge frame31. The supply gear44is fixedly coupled to a left end portion of the rotation shaft of the supply roller12protruding leftward from the left side wall33L such that relative rotation therebetween is prevented. The supply gear44is positioned below and spaced apart from the developing gear43.

The developing coupling45is rotatably supported to the left side wall33L of the cartridge frame31and positioned frontward of the developing gear43. The developing coupling45is generally cylindrical shaped extending in the lateral direction. The developing coupling45integrally includes a large-diameter gear portion48, a small-diameter gear portion49, and a coupling portion50.

The large-diameter gear portion48is provided at a right end portion of the developing coupling45. Gear teeth are provided along the entire circumferential surface of the large-diameter gear portion48. The large-diameter gear portion48is meshingly engaged with the developing gear43from a front side thereof.

The small-diameter gear portion49is generally cylindrical shaped extending leftward continuously from a left end portion of the large-diameter gear portion48and coaxial with the large-diameter gear portion48. The small-diameter gear portion49has an outer diameter smaller than that of the large-diameter gear portion48. Gear teeth are provided along the entire circumferential surface of the small-diameter gear portion49. The small-diameter gear portion49is meshingly engaged with the supply gear44from an upper-front side thereof.

The coupling portion50is generally cylindrical shaped extending leftward continuously from a left end portion of the small-diameter gear portion49and coaxial with the large-diameter gear portion48. The coupling portion50has an outer diameter smaller than that of the small-diameter gear portion49. The coupling portion50has a left side surface provided with a fitting portion51. In a state where the developing cartridge7is assembled to the main casing2, a leading end portion of a main coupling (not shown) provided to the main casing2is fixedly coupled to the fitting portion51such that relative rotation therebetween is prevented. A driving force from the main casing2is transmitted to the fitting portion51through the main coupling (not shown).

The idle gear46is rotatably supported to the left side wall33L of the cartridge frame31at a front side of the developing coupling45. The idle gear46is generally disk shaped having a thickness in the lateral direction. The idle gear46integrally includes a large-diameter portion52and a small-diameter portion53.

The large-diameter portion52constitutes a left half portion of the idle gear46. The large-diameter portion52is generally disk shaped having gear teeth formed along the entire circumference thereof. The large-diameter portion52is meshingly engaged with the small-diameter gear portion49of the developing coupling45from a lower-front side thereof.

The small-diameter portion53constitutes a right half portion of the idle gear46and is coaxial with the large-diameter portion52. The small-diameter portion53is generally disk shaped having gear teeth formed along the entire circumference thereof. The small-diameter portion53is disposed diagonally below and frontward of the large-diameter gear portion48of the developing coupling45and spaced apart therefrom.

The agitator gear47is fixedly coupled to a left end portion of the agitator shaft16protruding leftward from the left side wall33L such that relative rotation therebetween is prevented. The agitator gear47is rotatably supported to the left side wall33L of the cartridge frame31through the agitator shaft16. The agitator gear47is meshingly engaged with the small-diameter portion53of the idle gear46from an upper front side thereof.

More specifically, as illustrated inFIG. 6, the agitator gear47is formed with a fitting hole54in which the agitator shaft16is fitted and a detected opening55.

The fitting hole54is positioned at a radially substantially center portion of the agitator gear47. The fitting hole54is generally D-shaped in a side view and penetrated through a thickness of the agitator gear47in the lateral direction. The left end portion of the agitator shaft16is generally D-shaped in correspondence with the shape of the fitting hole54, and non-rotatably fitted into the fitting hole54so that relative rotation between the agitator gear47and the agitator shaft16is prevented.

The detected opening55is positioned between the gear teeth of the agitator gear47and the fitting hole54. The detected opening55is an opening penetrating a thickness of the agitator gear47in the lateral direction. The detected opening55has a generally arcuate shape extending in a circumferential direction of the agitator gear47. The detected opening55is defined by an upstream surface56and a downstream surface57. The upstream surface56is positioned upstream of the downstream surface57in a clockwise direction in a left side view. The upstream surface56is inclined diagonally rightward in a direction from an upstream end to a downstream end of the upstream surface56in the clockwise direction in a left side view. The downstream surface57is inclined diagonally leftward from an upstream end to a downstream end of the downstream surface57in the clockwise direction in a left side view.

(2-2) Gear Cover

As shown inFIG. 3, the gear cover42includes a main portion61and a shutter62.

As shown inFIGS. 3 and 7, the main portion61is generally hollow prismatic body shaped and extends in the lateral direction with its leftmost end being closed. The main portion61includes a collar portion63, a support portion66, and a regulation portion67. Further, the main portion61is formed with a detection opening64and an exposure opening65.

The collar portion63is positioned at a rear end portion of a left wall of the main portion61and protrudes leftward from the left wall of the main portion61. The collar portion63is generally hollow cylindrical shaped with its right end portion being in communication with an internal space of the main portion61.

The coupling portion50of the developing coupling45extends through the collar portion63and is rotatable relative to the collar portion63. The fitting portion51of the coupling portion50is exposed to the outside through a left end portion of the collar portion63.

The detection opening64is generally circular shaped in a side view. The detection opening64is positioned at a generally center portion of the left wall of the main portion61in the frontward/rearward direction such that the detection opening64confronts a lower front end portion of the agitator gear47from a left side thereof. The detection opening64is penetrated through a thickness of the left wall of the main portion61.

The exposure opening65is generally square shaped in a front view. The exposure opening65is positioned at a lower end portion of a front wall of the main portion61. The exposure opening65is penetrated through a thickness of the front wall of the main portion61.

The support portion66is generally rectangular shaped in a side view and elongated in the frontward/rearward direction. The support portion66is disposed at a right surface side of the left wall of the main portion61and at a rear side of a lower end portion of the exposure opening65. The support portion66protrudes upward from a lower wall of the main portion61.

The regulation portion67is a protrusion protruding rightward from the left wall of the main portion61and extending in the frontward/rearward direction. The regulation portion67is disposed at the right surface side of the left wall of the main portion61and at a rear side of an upper end portion of the exposure opening65.

As shown inFIGS. 3 and 8, the shutter62integrally includes a slider71, a display portion73, and a cover portion72.

The slider71is generally flat plate shaped extending in the frontward/rearward direction. Gear teeth are provided at an upper surface of a rear end portion of the slider71. In the slider71, a portion where gear teeth are provided will be referred to as a toothed portion74, and a portion where gear teeth are not provided will be referred to as toothless portion75.

The display portion73is generally rectangular flat-plate shaped in a front view extending continuously from a front end portion of the slider71and inclined diagonally upward toward a front side of the display portion73.

The cover portion72is generally rectangular flat-plate shaped in a side view extending upward continuously from left end portions of the slider71and the display portion73.

As shown inFIG. 9, within the main portion61, the shutter62is slidably mounted on the support portion66of the main portion61such that the cover portion72is positioned between the support portion66and regulation portion67.

This configuration allows the shutter62to move to a covered position (FIG. 10A) and to an exposed position (FIG. 10B). At the covered position, the shutter62covers the lower front end portion of the agitator gear47. At the exposed position, the shutter62allows the lower front end portion of the agitator gear47to be exposed to the outside.

When the shutter62is at the covered position (FIG. 10A), the cover portion72of the shutter62is interposed between the detection opening64and the lower front end portion of the agitator gear47. Further, the display portion73of the shutter62is retracted rearward from the exposure opening65of the main portion61. Further, the toothed portion74of the shutter62is meshingly engaged with a lower end portion of the agitator gear47.

When the shutter62is at the exposed position (FIG. 10B), the cover portion72of the shutter62is advanced frontward from a position between the detection window64and the lower front end portion of the agitator gear47. At this time, the display portion73of the shutter62is exposed to the outside (a front side of the exposure opening65) through the exposure opening65of the main portion61. Further, the toothed portion74of the shutter62is positioned frontward of the lower end portion of the agitator gear47and spaced apart therefrom.

3. Main Casing

As shown inFIGS. 2,11A,11B,12A, and12B, a detection unit78, an empty sensor unit79, and a CPU82are provided within the main casing2.

The detection unit78is positioned at a left side of the developing cartridge7within the main casing2. As shown inFIGS. 11A through 12B, the detection unit78includes a slide member84, a probe87, an actuator88, and a photo-sensor89.

The slide member84is a generally rectangular flat plate shaped extending in the vertical direction. The slide member84is slidably movable in the lateral direction by a moving mechanism (not shown).

The probe87is generally cylindrical shaped extending in the lateral direction. The probe87is movably supported in the slide member84. The probe87is slidably movable in the lateral direction to an advanced position (FIGS. 11B and 12B) and to a retracted position (FIGS. 11A and 12A). At the advanced position, the probe87is advanced rightward, and at the retracted position, the probe87is retracted leftward from the advanced position. The probe87is connected to a compression coil spring86, so that the probe87is normally urged rightward by the compression coil spring86so as to be positioned at the advanced position.

The actuator88integrally includes a pivot shaft91, an abutment lever92, and a light shielding lever93. The pivot shaft91extends in the frontward/rearward direction and is generally hollow cylindrical shaped. The abutment lever92extends upward from the pivot shaft91. The light shielding lever93extends downward from the pivot shaft91. The light shielding lever93has a lower end portion provided with a light shielding plate94extending in the lateral direction.

The actuator88is supported to the slide member84and pivotally movable relative to the slide member84about the pivot shaft91.

The actuator88is pivotally movable to a light transmitting position (FIGS. 11B and 12B) and to a light shielding position (FIGS. 11A and 12A). At the light transmitting position, the abutment lever92is directed diagonally upward and rightward and the light shielding lever93is directed diagonally downward and leftward. At the light shielding position, the abutment lever92and the light shielding lever93are directed in the vertical direction.

The photo-sensor89includes a light emitting portion95and a light receiving portion96. The light emitting portion95is adapted to emit a light. The light receiving portion96is adapted to receive the light from the light emitting portion95and positioned in confrontation with and downward of the light emitting portion95with a gap therebetween. The photo-sensor89is positioned below the actuator88such that the light shielding plate94of the actuator88at the light shielding position is positioned between the light emitting portion95and the light receiving portion96in the vertical direction.

At the light shielding position of the actuator88, the light shielding plate94of the actuator88is positioned between the light emitting portion95and the light receiving portion96, so that the light emitted from the light emitting portion95of the photo-sensor89is blocked by the light shielding plate94of the light shielding lever93, whereupon an ON signal is outputted from the photo-sensor89.

On the other hand, at the light transmitting position of the actuator88, the light shielding plate94of the actuator88is retracted leftward from the gap between the light emitting portion95and the light receiving portion96. Thus, the light emitted from the light emitting portion95of the photo-sensor89is received by the light receiving portion96. At this time, an ON signal is not outputted from the photo-sensor89.

Further, the detection unit78is movable within the main casing2to a new cartridge detection position (FIGS. 11A and 11B) and to a cartridge type detection position (FIGS. 12A and 12B). At the new cartridge detection position, the detection unit78detects whether the developing cartridge7is new or used. At the cartridge type detection position, the detection unit78detects types of the developing cartridge7.

As shown inFIG. 2, the empty sensor unit79includes a light emitting element80and a light receiving element81.

The light emitting element80is positioned within the main casing2and in confrontation with the detection opening64of the gear cover42from a left side thereof. The light emitting element80is adapted to emit a-detection light to the detection opening64.

The light receiving element81is positioned within the main casing2and in confrontation with the detection window (not shown) of the right side wall33R of the cartridge frame31from a right side thereof. The light receiving element81outputs an ON signal upon receipt of the detection light emitted from the light emitting element80.

A combination of the detection unit78and the empty sensor unit79constitutes a claimed detection unit.

The CPU82is electrically connected to the photo-sensor89and the light receiving element81so as to receive the ON signal from the photo-sensor89and the ON signal from the light receiving element81.

4. Operation for Detecting New Developing Cartridge

An operation for detecting a new developing cartridge7will be described. Note that, in the present embodiment, when the developing cartridge7is an unused (new) cartridge, the shutter62is at the covered position. That is, the covered position of the shutter62indicates that the developing cartridge7is unused (new).

In order to assemble the unused developing cartridge7into the main casing2, the unused developing cartridge7is first attached to the drum cartridge6.

At this time, a user looks at the gear cover42of the developing cartridge7to confirm that the display portion73of the shutter62is not exposed to the outside through the exposure opening65. Thus, the user can determine that the developing cartridge7is unused. In order to let the user know how to determine whether the developing cartridge7is new or used, for example, the following description is given in an instruction manual of the printer1: the developing cartridge7is unused in a case where the display portion73of the shutter62is not exposed to the outside through the exposure opening65, while the developing cartridge7is in a used state in a case where the display portion73of the shutter62is exposed to the outside through the exposure opening65. The user may determine a used or unused state of the developing cartridge7by looking at the shutter62as to whether the shutter62is visible or invisible through the detection opening64.

Then, in order to assemble the unused developing cartridge7into the main casing2, the top cover4of the main casing2is opened to insert, from diagonally above and frontward thereof, into the main casing2the process cartridge5to which the unused developing cartridge7is assembled. After the process cartridge5is inserted into the main casing2, the top cover4is closed. In association with closing movement of the top cover4, the main coupling (not shown) provided in the main casing2is coupled to the developing coupling45, preventing relative rotation therebetween.

As shown inFIG. 11A, the detection unit78is positioned at the new cartridge detection position before the main coupling (not shown) is driven.

Then, a right end portion of the probe87is brought into contact with the cover portion72of the shutter62from a left side thereof through the detection opening64of the main portion61.

Then, the probe87is pressed leftward against the urging force of the compression coil spring86to be positioned at the retracted position. At the same time, the actuator88is pivotally moved in the counterclockwise direction in a front view to be positioned at the light shielding position

As a result, the photo-sensor89outputs the ON signal to the CPU82. That is, the detection unit78detects the covered position of the shutter62.

Then, the CPU82determines that the shutter62has been positioned at the covered position upon receipt of the ON signal from the photo-sensor89in a state where the detection unit78is at the new cartridge detection position.

Then, a driving force from the main casing2is transmitted to the developing coupling45through the main coupling (not shown) for starting a warm-up operation. Then, a driving force from the developing coupling45is transmitted to the agitator gear47through the gear train41. As a result of rotation of the agitator gear47in the counterclockwise direction in a left side view, the agitator15is rotated in the counterclockwise direction in a left side view.

At the same time, the counterclockwise rotation of the agitator gear47in a left side view causes the shutter62to move from the covered position to the exposed position.

Then, as shown inFIG. 11B, the cover portion72of the shutter62is retracted frontward from a position between the detection opening64and the lower front end portion of the agitator gear47, and the probe87is pressed rightward by the urging force of the compression coil spring86to be positioned at the advanced position. At the same time, the actuator88is pivotally moved in the clockwise direction in a front view from the light shielding position to the light transmitting position.

As a result, output of the ON signal from the photo-sensor89to the CPU82is interrupted. That is, the detection unit78detects the exposed position of the shutter62.

Then, the CPU82determines that the shutter62has been moved from the covered position to the exposed position due to interruption of the ON signal from the photo-sensor89.

When having sequentially determined, within a predetermined period of time, that the shutter62is positioned at the covered position and the shutter62is positioned at the exposed position, the CPU82determines that the developing cartridge7is unused.

That is, the CPU82determines that the developing cartridge7is an unused cartridge when the detection unit78detects a movement of the shutter62from the covered position to the exposed position within a predetermined time period.

Subsequently, as shown inFIG. 12A, the detection unit78is moved rightward to be positioned at the cartridge type detection position while the agitator gear47is rotated continuously.

Then, the right end portion of the probe87is brought into contact with the agitator gear47from a left side thereof.

Then, the probe87is pressed leftward against the urging force of the compression coil spring86to be positioned at the retracted position. At the same time, the actuator88is pivotally moved in the counterclockwise direction in a front view to be positioned at the light shielding position.

As a result, the photo-sensor89outputs the ON signal to the CPU82.

Then, the CPU82determines that the probe87has been moved from the advanced position to the retracted position upon receipt of the ON signal from the photo-sensor89.

Then, as shown inFIG. 12B, further rotation of the agitator gear47causes the probe87to face the detected opening55of the agitator gear47.

As a result, the probe87is pressed rightward by the urging force of the compression coil spring86to be positioned at the advanced position. At the same time, the actuator88is pivotally moved in the clockwise direction in a front view from the light shielding position to be positioned at the light transmitting position.

Thus, output of the ON signal from the photo-sensor89to the CPU82is interrupted. That is, the detection unit78detects the detected opening55of the agitator gear47.

Then, the CPU82determines that the detected opening55of the agitator gear47has been detected due to interruption of the ON signal from the photo-sensor89in a state where the detection unit78is at the cartridge type detection position.

Then, the CPU82determines the type of the developing cartridge7in accordance with the number of times of interruption of the ON signal from the photo-sensor89per unit time.

For example, in a case where a single detected opening55is formed in the agitator gear47(FIG. 6), the ON signal from the photo-sensor89is interrupted once during one rotation of the agitator15. In this case, the CPU82determines that a predetermined printing times is 6,000 sheets printing.

In a case where two detected openings55are formed in the agitator gear47so as to be angularly spaced away from each other by 180 degrees (seeFIG. 14A), the ON signal from the photo-sensor89is interrupted twice during one rotation of the agitator15. In this case, the CPU82determines that a predetermined printing times is 3,000 sheets printing.

That is, the number of the detected openings55corresponds to information about the types of the developing cartridge7. More specifically, the case where the agitator gear47is formed with a single detected opening55corresponds to information (first information) about the types of the developing cartridge7indicating that the predetermined printing times is 6,000 sheets printing, and the case where the agitator gear47is formed with two detected openings55corresponds to information (second information) about the types of the developing cartridge7indicating that the predetermined printing times is 3,000 sheets printing.

Thereafter, the CPU82counts actual printing times starting from assembly of the unused developing cartridge7into the main casing2, and notifies and displays on an operation panel (not shown) an exchanging timing of the developing cartridge7when the counted printing times approaches a predetermined printing times in accordance with the types of the developing cartridge7.

Incidentally, the CPU82determines that the developing cartridge7has been detached from the main casing2when the type of the developing cartridge7has not been detected within a predetermined period of time.

On the other hand, there is a case where after the unused developing cartridge7is assembled, the developing cartridge7is again assembled to the main casing2after the developing cartridge7is detached from the main casing2, for example, for removing a jammed sheet P. In such a case, the shutter62is stopped at the exposed position.

At this time, the user looks at the gear cover42of the developing cartridge7to confirm that the display portion73of the shutter62is exposed to the outside through the exposure opening65. Thus, the user determines that the developing cartridge7is an old cartridge (a cartridge in use).

After the used developing cartridge7that has once been detached is assembled once again into the main cartridge2, the probe87is not positioned at the retracted position but stays at the advanced position as shown inFIG. 11Bwhen the detection unit78is positioned at the new cartridge detection position. Thus, the CPU82does not receive the ON signal from the photo-sensor89.

Accordingly, the CPU82determines that the shutter62has stayed at the exposed position. Further, the CPU82determines that the re-assembled cartridge7is an old cartridge.

Then, the CPU82continues comparison between the predetermined printing times and the accumulated total number of printing times from the timing at which the CPU82determines that the assembled developing cartridge7is a new cartridge.

5. Operation for Detecting Remaining Amount of Toner in Developing Cartridge

An operation for detecting a remaining amount of toner in the developing cartridge7will be described.

Although not illustrated, after completion of the new cartridge detection operation and the cartridge type detection operation, the detection unit78is retracted from an optical path of the detection light emitted from the light emitting element80.

Then, when the detected opening55and the detection window38are opposed to each other by rotation of the agitator gear47as shown inFIG. 13A, the detection light enters the toner chamber14passing through the detection window38. That is, the detected opening55serves also as a light guiding portion that guides the detection light to the toner chamber14.

When an amount of the toner in the toner chamber14is reduced to allow the detection light to pass through the toner chamber14and the detection window (not shown) of the right side wall33R of the cartridge frame31, and thus, the detection light is received by the light receiving element81, the light receiving element81outputs an ON signal to the CPU82.

By receiving the ON signal from the light receiving element81, the CPU82determines that the amount of the toner in the toner chamber14is reduced.

Also in this case, the CPU82notifies and displays on an operation panel (not shown) that an exchanging timing of the developing cartridge7is approaching.

(1) According to the developing cartridge7and the printer1, the shutter62is irreversibly movable from the covered position (FIG. 10A) to the exposed position (FIG. 10B).

When the detection unit78detects the movement of the shutter62within a predetermined period of time, the CPU82determines that the developing cartridge7is unused.

Thus, in a state where the developing cartridge7is assembled into the main casing2, the movement of the shutter62allows the detection unit78of the main casing2to detect the information as to whether the developing cartridge7is used or unused.

Further, in a state where the developing cartridge7is detached from the main casing2, the user can easily visually confirm a position of the display portion73of the shutter62.

Thus, the user can easily recognize whether the developing cartridge7is used or unused by confirming displacement of the display portion73of the shutter62.

(2) Further, according to the developing cartridge7and the printer1, the developing cartridge7can be determined to be unused when the display portion73of the shutter62is positioned at the exposed position.

(3) Further, according to the developing cartridge7and the printer1, the agitator gear47can be covered by the shutter62before the driving force is inputted to the gear train41, i.e., when the developing cartridge7is unused, as shown inFIG. 10A.

Thus, when the developing cartridge7is unused, the agitator gear47can be protected.

(4) Further, according to the developing cartridge7and the printer1, by positioning the detection unit78at the cartridge type detection position after the shutter62has been positioned at the exposed position as shown inFIG. 12, the types of the developing cartridge7can be detected.

Thus, during the use of the developing cartridge7, the detection unit78can detect the types of the developing cartridge7at an arbitrary timing.

(5) Further, according to the developing cartridge7and the printer1, the detected opening55serves also as a light guiding portion for guiding the detection light emitted from the light emitting element80of the empty sensor unit79to the toner chamber14as shown inFIG. 13A.

Thus, the empty sensor unit79can detect the remaining amount of toner in the toner chamber14.

(1) In the above-described embodiment, the remaining amount of toner in the toner chamber14is detected by means of the empty sensor unit79. Alternatively, however, as shown inFIG. 13B, a position of the agitation blades17of the agitator15can be determined by means of the empty sensor unit79. In this case, it is assumed that a toner level is below the detection window38and the detection light emitted from the light emitting element80is always received by the light receiving element81.

When the agitation blades17extending from the agitator shaft16confront the detection window38during rotation of the agitator15, the detection light is blocked by the agitation blades17. As a result, output of the ON signal from the light receiving element81to the CPU82is interrupted.

Then, the CPU82determines that the agitation blades17are in confrontation with the detection window38due to interruption of the ON signal from the light receiving element81.

According to the modification, the position of the agitation blades17of the agitator15can be detected by means of the empty sensor unit79.

Thus, rotation of the agitator15can be controlled so as to stop the agitation blades17at a desired position.

According to this modification, operations and effects similar to those of the above-described embodiment can also be obtained.

(2) Further, in the above-described embodiment, the empty sensor unit79includes the light emitting element80and the light receiving element81. The light emitting element80is positioned at a left side of the developing cartridge7, and the light receiving element81is positioned at a right side of the developing cartridge7. The detection light from the light emitting element80is received by the light receiving element81.

Alternatively, however, a configuration may be possible in which both the light emitting element80and the light receiving element81are positioned at a left side of the developing cartridge7and a reflection plate is positioned at a right side of the developing cartridge7to allow the detection light from the light emitting element80to be reflected by the reflection plate and received by the light receiving element81.

(3) In the above-described embodiment, the shutter62is positioned at the covered position in a state where the developing cartridge7is unused, and the shutter62is moved from the covered position to the exposed position in the new cartridge detection operation. Alternatively, however, a configuration may be possible in which the shutter62is positioned at the exposed position in a state where the developing cartridge7is unused and the shutter62is moved from the exposed position to the covered position in the new cartridge detection operation.

Then, after the shutter62is positioned at the covered position, the toothed portion74of the shutter62is moved rearward of the agitator gear47so as to be spaced away from the agitator gear47, and the toothless portion75of the shutter62is opposed to the agitator gear47from below.

As a result, meshing engagement between the toothed portion74of the shutter62and the agitator gear47is released.

Note that, in this modification, the cartridge type detecting operation and the toner amount detecting operation may be performed by methods different from those described in the above embodiment and known to those skilled in the art.

According to this modification, the agitator gear47can be covered after input of the driving force to the gear train41, i.e., while the developing cartridge7is being used.

Thus, the agitator47can be protected while the developing cartridge7is being used.

Further, the shutter62includes the toothed portion74to which the driving force is transmitted and the toothless portion75to which the driving force is not transmitted. Accordingly, the shutter62can be stopped reliably after being moved with a predetermined moving amount.

Thus, the shutter62can reliably be irreversibly moved with a simple configuration.

According to this modification, operations and effects similar to those of the above-described embodiment can also be obtained.

(4) Further, in the above-described embodiment, the number of the detected openings55formed in the agitator gear47corresponds to information about the type of the developing cartridge7. Further, the CPU82determines the type of the developing cartridge7in accordance with the number of times of interruption of the ON signal from the photo-sensor89per unit time.

Alternatively, however, a length of the detected opening55in a circumferential direction of the agitator gear47may be made to correspond to the information about the type of the developing cartridge7.

For example, in a case where the length of the detected opening55in the circumferential direction of the agitator47is long, this length of the detected opening55corresponds to the information (first information) about the type of the developing cartridge7indicating that a predetermined printing times is 6,000 sheets printing. Further, in a case where the length of the detected opening55in the circumferential direction of the agitator47is short, this length of the detected opening55corresponds to the information (second information) about the type of the developing cartridge7indicating that a predetermined printing times 3,000 sheets printing.

Thus, the CPU82determines the types of the developing cartridge7in accordance with duration of interruption of the ON signal from the photo-sensor89.

More specifically, in a case where the duration of interruption of the ON signal from the photo-sensor89is long, the CPU82determines that the predetermined printing times is 6,000 sheets printing. Further, in a case where the duration of interruption of the ON signal from the photo-sensor89is short, the CPU82determines that the predetermined printing times is 3,000 sheets printing.

According to this modification, operations and effects similar to those of the above-described embodiment can also be obtained.

(5) Further, in the above-described embodiment, the detected opening55is formed in the agitator gear47. However, a shape of the detected portion is not specifically limited. For example, as shown inFIG. 14B, two detected projections100may be provided in the agitator gear47.

Each of the detected projections100is formed as a projection protruding leftward from a left surface of the agitator gear47. The detected projection100is defined by a first sloped surface98and a second sloped surface99. The first sloped surface98is positioned downstream of the second sloped surface99in the clockwise direction in a left side view. The first sloped surface98is inclined diagonally rightward from an upstream end to a downstream end of the first sloped surface98in the clockwise direction in a left side view. The second sloped surface99is inclined diagonally leftward from an upstream end to a downstream end of the second sloped surface99in the clockwise direction in a left side view.

Note that, in this modification, the toner amount detecting operation may be performed by a method different from that described in the above embodiment and known to those skilled in the art.

According to this modification, the detection unit78is allowed to detect the types of the developing cartridge7with a simple configuration.

According to this modification, operations and effects similar to those of the above-described embodiment can also be obtained.

(6) Further, in the above-described embodiment, the detection unit78is movable to the new cartridge detection position and to the cartridge type detection position. Alternatively, however, appropriate arrangement of the slide member84, the probe87, the actuator88, and the photo-sensor89allows detection of whether the developing cartridge7is used or unused and detection of the type of the developing cartridge7without moving the detection unit78.