JP4816801B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a laser printer.

  2. Description of the Related Art An electrophotographic image forming apparatus such as a laser printer is known in which a developing cartridge in which a toner storage chamber for storing toner is formed is detachably mounted.

  In such an image forming apparatus, when the toner stored in the toner storage chamber is consumed, the developing cartridge is replaced. In order to detect the remaining amount of toner, a developer remaining amount detecting means is provided. I have.

  As such a developer remaining amount detecting means, for example, a light transmission window is provided on both side walls in the width direction of the toner storage chamber of the developing device, and the optical axis of the light transmitted through the light transmission window is one side of the both side walls. It has been proposed to provide a light-emitting element and a light-receiving element of the developer remaining amount detecting means so as to cross from one side to the other side (see, for example, Patent Document 1).

JP 2000-258984 A

  However, the conventional developer remaining amount detecting means as described above has a light emitting element and a light receiving element facing each other on both sides of the toner containing chamber, and the light receiving element emits light from the light emitting element and passes through the toner containing chamber. The remaining amount of toner is determined by detecting the passing state of the detection light in the toner storage chamber. In such a developer remaining amount detecting means, all the detection light emitted from the light emitting element passes through only one specific place in the toner containing chamber and is received by the light receiving element.

  However, since the detection light passes through only one specific place in the toner containing chamber, if there is an abnormality in the specific one place, an erroneous detection occurs immediately, so that the remaining amount of toner cannot be accurately determined. .

  An object of the present invention is to provide an image forming apparatus capable of accurately detecting and determining the amount of developer in a developer container.

The image forming apparatus according to claim 1, to supply the developer to the photosensitive member on which an electrostatic latent image is formed, a developer accommodating portion for accommodating a developer therein, said developer accommodating portion The detection light emitted from the light emitting unit with respect to a detection window that passes through the detection light for detecting the amount of developer and one light emitting unit that emits the detection light to the detection window An optical sensor having one light receiving unit that receives light, and a determination unit that determines an amount of developer based on a light reception result of the light receiving unit, wherein the developer containing unit has the same detection light. so as to pass through the different positions in the vertical direction within the detection window, between a first position and a second position having a vertical direction component, and the image which the image is formed with respect to the photosensitive member The recording medium conveyance direction at the formation position and the recording medium orthogonal thereto Is movable along a direction inclined with respect to the thickness direction, the determining means, receiving the detection light that has passed through the detection window, respectively, in the first position and the second position by the light receiving portion The amount of the developer is determined based on each received light result.

  The image forming apparatus according to claim 2, wherein the determination unit includes the first position, the second position, and the detection corresponding to the first position. A developer amount is determined based on a light reception result and a detection light reception result corresponding to the second position.

  According to a third aspect of the present invention, there is provided the image forming apparatus according to the first or second aspect, further comprising a notifying unit for notifying a developer amount based on a determination result of the determining unit. It is characterized by being.

The image forming apparatus according to claim 4 is the image forming apparatus according to any one of claims 1 to 3 , wherein the first position and the second position are a maximum movement of the developer accommodating portion. It is characterized by being at both ends of the range.

The image forming apparatus according to claim 5 is the image forming apparatus according to any one of claims 1 to 4, wherein the developer carrying member for carrying the developer and the developer containing the developer containing portion. The cartridge, the photosensitive member on which the electrostatic latent image is formed, and the developer carrying member are arranged above the photosensitive member.
The image forming apparatus according to claim 6 is an image forming apparatus according to claim 5 , further comprising contact / separation means for moving the developer cartridge so that the developer carrying member contacts and separates from the photosensitive member. The developer accommodating portion moves between the first position and the second position by the movement of the developing cartridge by the contact / separation means.

The image forming apparatus according to claim 7 is the image forming apparatus according to claim 6 , wherein the first position is a state where the developer carrier and the photoconductor are in contact with each other, and the second position is When the developer carrying member and the photosensitive member are separated from each other, the developer containing unit is moved from the second position by the movement of the developer containing unit accompanying the movement of the developing cartridge by the contact / separation unit. The detection light is received by the light receiving unit at the timing of moving to the first position, and the determination unit determines the amount of developer based on the light reception result.

An image forming apparatus according to claim 8 is the image forming apparatus according to any one of claims 5 to 7 , comprising a photosensitive cartridge including the photosensitive member, the photosensitive cartridge, the developing cartridge, Is characterized in that a plurality of sets are provided corresponding to a plurality of colors, with the photosensitive cartridge and the developing cartridge as a set.

An image forming apparatus according to a ninth aspect is the image forming apparatus according to the eighth aspect, wherein the photoconductors are arranged in a horizontal direction.
An image forming apparatus according to a tenth aspect is the image forming apparatus according to the eighth or ninth aspect, wherein a supply means for picking up and supplying the recording medium and a discharge means for discharging the recording medium are provided. A plurality of sets of the photosensitive cartridge and the developing cartridge are disposed between the supply unit and the discharge unit in a recording medium conveyance path, and a pickup direction of the recording medium picked up by the supply unit; The recording medium conveyance direction at the image forming position where images are sequentially formed by the plurality of sets of the photosensitive cartridge and the developing cartridge is opposite to the recording medium conveyance direction at the image forming position, and the discharge. The recording medium is arranged so that the recording medium is discharged in the direction opposite to the discharge direction.

The image forming apparatus according to claim 11, in the image forming apparatus according to claim 10, wherein the photosensitive member cartridge and the developing cartridge, a recording medium conveying direction and Cartesian to the recording medium at the image forming position It is characterized by being attached and detached along the direction of inclination with respect to the thickness direction.

  An image forming apparatus according to a twelfth aspect is the image forming apparatus according to the tenth or eleventh aspect, wherein a plurality of exposure apparatuses are provided corresponding to the plurality of sets of the photosensitive cartridges and the developing cartridges, In the conveyance direction of the recording medium at the image forming position, a plurality of sets of the photosensitive cartridges and the developing cartridges and corresponding exposure apparatuses are alternately arranged.

  According to the image forming apparatus of the first aspect, the detection light is allowed to pass through the detection window when the developer containing portion is at the first position and the second position. Can be passed. Therefore, even if an erroneous detection occurs at one of the positions, it can be accurately detected at the other position.

  The determination unit can determine the amount of the developer based on the light reception result of the light receiving unit at the first position and the second position of the developer storage unit. Therefore, it is possible to accurately determine the amount of developer.

  The detection light passes through the same window at the first and second positions. Therefore, compared with the case where a plurality of windows are provided corresponding to the first position and the second position, it is possible to reduce the rate at which the developer leaks from the detection window.

In addition, since the first position and the second position are switched by the movement of the developer accommodating portion, it is not necessary to provide a plurality of photosensors corresponding to the first position and the second position.
Therefore, the apparatus configuration can be simplified and the cost can be reduced.
Further, in the developer accommodating portion, the detection light that passes through the first position and the second position that are different in the vertical direction can be received by the light receiving portion. For this reason, the amount of developer can be detected with higher accuracy.
Further, the developer accommodating portion moves between the first position and the second position in the vertical direction by the vertical movement of the developer accommodating portion. Therefore, highly accurate detection of detection light can be achieved with a simple configuration.

  According to the image forming apparatus of the second aspect, the determination unit includes the first position and the second position, the light reception result of the detection light corresponding to the first position, and the detection light corresponding to the second position. Based on the light reception result, the amount of the developer is determined. Therefore, the amount of developer can be determined in more detail.

  According to the image forming apparatus of the third aspect, the notifying unit notifies the user of the amount of the developer based on the determination result of the determining unit, so the amount of the developer based on the determination result of the determining unit is notified to the user. It can be recognized.

According to the image forming apparatus of the fourth aspect , it is possible to ensure a wide range in which the amount of developer is detected. Therefore, the amount of developer can be detected appropriately.

According to the image forming apparatus of the sixth aspect , the developer accommodating portion moves between the first position and the second position as the developing cartridge is moved by the contacting / separating means. Therefore, it is not necessary to newly provide a mechanism for moving the developer container for detecting the remaining amount of developer, and the configuration of the apparatus can be simplified.

According to the image forming apparatus of the seventh aspect , the determination unit determines the amount of the developer at the timing when the developer accommodating portion moves in accordance with the movement of the developer cartridge by the contact / separation unit. Therefore, it is possible to detect the amount of developer at an appropriate timing, and to detect the amount of developer more accurately.

According to the image forming apparatus of the eighth aspect , the photosensitive cartridge and the developing cartridge are provided as a set corresponding to a plurality of colors, so that a color image is formed while reducing the size. be able to.

  According to the tenth aspect of the present invention, the recording medium pickup direction and the recording medium conveyance direction at the image forming position are opposite directions, and the recording medium conveyance direction and the recording medium ejection direction at the image forming position are Since it is arranged so as to be in the opposite direction, the apparatus can be miniaturized while ensuring the conveyance path of the recording medium.

  According to the image forming apparatus of claim 11, the photosensitive cartridge and the developing cartridge are along a direction inclined with respect to the conveyance direction of the recording medium at the image forming position and the thickness direction of the recording medium orthogonal thereto. Since it is attached and detached, the operability of attaching and detaching the photosensitive cartridge and the developing cartridge can be improved.

  According to the image forming apparatus of the twelfth aspect, a plurality of sets of photosensitive cartridges and developing cartridges and a plurality of exposure apparatuses corresponding thereto are alternately arranged. Therefore, the apparatus can be reduced in size by these efficient arrangements.

1 is a cross-sectional side view of a main part showing an embodiment of a color laser printer as an image forming apparatus of the present invention. It is the perspective view which looked at the drum cartridge of the color laser printer shown in FIG. 1 from the front side top surface side. It is the perspective view which looked at the drum cartridge of the color laser printer shown in FIG. 1 from the back side bottom face side. It is a top view of the drum cartridge of the color laser printer shown in FIG. It is a front view of the drum cartridge of the color laser printer shown in FIG. It is a right view of the drum cartridge of the color laser printer shown in FIG. It is a left view of the drum cartridge of the color laser printer shown in FIG. It is the perspective view seen from the front top surface side of the developing cartridge of the color laser printer shown in FIG. FIG. 2 is a perspective view of the color laser printer shown in FIG. 1 as viewed from the rear bottom surface side of the developing cartridge. FIG. 2 is a front view of a developing cartridge of the color laser printer shown in FIG. 1. FIG. 2 is a right side view of the developing cartridge of the color laser printer shown in FIG. 1. FIG. 2 is a left side view of the developing cartridge of the color laser printer shown in FIG. 1. FIG. 2 is a plan view of a developing cartridge of the color laser printer shown in FIG. 1. FIG. 2 is a bottom view of the developing cartridge of the color laser printer shown in FIG. 1. FIG. 2 is an exploded perspective view of a developing cartridge of the color laser printer shown in FIG. 1. FIG. 2 is a side sectional view of a main part of a developing cartridge of the color laser printer shown in FIG. 1. It is the perspective view seen from the front side upper part of the main body casing of the color laser printer shown in FIG. It is a side view for demonstrating mounting | wearing with respect to the main body casing of a drum cartridge and a developing cartridge. FIG. 10 is a side view illustrating a mounting state of the developing cartridge with respect to the process accommodating portion (a state before insertion of the developing boss portion into the boss insertion groove). FIG. 10 is a side view illustrating a mounted state (separated state) of the developing cartridge with respect to the process storage unit. FIG. 6 is a side view illustrating a mounting state (contact state) of the developing cartridge with respect to a process storage unit. FIG. 6 is a plan view for explaining a mounted state (separated state) of a developing cartridge with respect to a process accommodating portion. FIG. 7 is a front view illustrating a mounted state (separated state) of the developing cartridge with respect to a process storage unit. FIG. 6 is a plan view illustrating a mounting state (contact state) of the developing cartridge with respect to a process storage unit. FIG. 6 is a front view for explaining a mounting state (contact state) of a developing cartridge with respect to a process accommodating portion. It is a principal part block diagram of the drive path | route of a cam, Comprising: (a) is a top view, (b) is a side view. FIG. 3 is a block diagram illustrating a control system for determining the remaining amount of toner. FIG. 6 is a flowchart of a toner remaining amount determination program. It is a block diagram which shows the control system of the toner remaining amount display program of a reference example. It is a flowchart of a toner remaining amount display program of a reference example.

  FIG. 1 is a cross-sectional side view of an essential part showing an embodiment of a color laser printer as an image forming apparatus of the present invention.

  In FIG. 1, the color laser printer 1 is a horizontal type tandem color laser printer in which a plurality of process units 27 are arranged in parallel in a horizontal direction, and a sheet 3 is placed in a main body casing 2. A paper feed unit 4 for feeding paper, an image forming unit 5 for forming an image on the fed paper 3, and a paper discharge unit 6 for discharging the paper 3 on which the image is formed are provided.

  The main casing 2 has a box-like shape that is substantially rectangular in a side view with the upper side opened, and a top cover 7 is provided on the upper side. The top cover 7 is rotatable via a hinge (not shown) provided on the back side of the main casing 2 (in the following description, the left side in FIG. 1 is the back side and the right side is the front side). The main casing 2 is openable and closable.

Moreover, as shown in FIG. 17, the main body casing 2 is spaced apart from each other in the width direction (the back direction (the direction extending between the front side and the back side) and the direction perpendicular to the vertical direction, the same applies hereinafter). There are provided a left side plate 8 and a right side plate 9 that are arranged opposite to each other, and a plurality of (four) partition plates 10 and a front side plate 11 that are installed between them. Each partition plate 10 and the front side plate 11 are provided so that each partition plate 10 partitions the normal back space between the left side plate 8 and the right side plate 9 for each process unit 27 described later. In the middle of the direction, the front side plates 11 are provided at intervals from each other, and the front side plates 11 are provided on the front side of the partition plates 10.

  Each of the partition plates 10 and the front side plate 11 has an upper end on the front side and a lower end on the back side in the normal direction (the same as the conveyance direction of the paper 3 at the image forming position described later) and the vertical direction. It is arranged to incline. Further, as shown in FIG. 1, each partition plate 10 and front side plate 11 are arranged such that their upper end portions are spaced apart from the top cover 7 in the vertical direction, and the lower end portions thereof are the upper and lower portions of the transfer portion 28 described later. It arrange | positions so that the space | interval may be separated in the direction.

  And in this main body casing 2, as shown in FIG. 17, each of the partition plates 10 and the front side plates 11 and the left side plate 8 and the right side plate 9 which are adjacent to each other are provided with a plurality ( Four) process accommodating portions 12 are defined.

  As shown in FIG. 18, each process accommodating portion 12 accommodates a drum cartridge 31 (to be described later) and a developing cartridge 32 (to be described later), a drum accommodating portion 13 to which a holder portion 43 of the drum cartridge 31 (to be described later) is mounted, and to be described later. And a developing container 14 in which the developing cartridge 32 is mounted.

  The drum accommodating portion 13 is provided below the respective partition plates 10. In the normal direction, each drum plate 13 and the front side plate 11 are partitioned by a virtual extension plane that extends downward in the inclined direction as it is, and in the width direction. Is divided by a left side plate 8 and a right side plate 9. The internal space partitioned by them is a drum housing space 15 for housing a holder portion 43 of the drum cartridge 31 described later.

  Further, the developing container 14 is mounted upstream of the drum cartridge 31 to be described later with respect to the drum container 13, that is, on the upstream side of the drum container 13. Are provided so as to be continuous with the drum accommodating portion 13, and are partitioned by the respective partition plates 10 and the front side plate 11 in the normal direction, and are partitioned by the left side plate 8 and the right side plate 9 in the width direction. . An internal space partitioned by them (except for an extended portion accommodating space 18 described later) is a developing accommodating space 16 for accommodating a developing cartridge 32 described later.

  In addition, as shown in FIG. 17, the developing accommodating portion 14 is provided with rail portions 17 that rub against each of the horn portions 51 of the drum cartridge 31 described later at both ends in the width direction of the partition plate 10. Each rail portion 17 is formed in a strip shape having a thickness along the attaching / detaching direction of the drum cartridge 3 1.

  As shown in FIG. 1, the paper feed unit 4 includes a paper feed tray 21 that is detachably attached to the main body casing 2 from the front side in the horizontal direction at the bottom of the main body casing 2, and the paper feed tray 21. Pickup roller 22 and paper feed roller 23 as supply means provided above the front side of the paper, a paper feed side U-shaped path 24 provided above the front side of the paper feed roller 23, and the middle of the paper feed-side U-shaped path 24 A conveying roller 25 and a registration roller 26 provided in the apparatus.

  The paper 3 is stacked in the paper feed tray 21, and the paper 3 at the top is first picked up by the pickup roller 22 and conveyed to the front side, and then fed by the paper feed roller 23. Paper is fed to the side U-shaped path 24.

The upstream end of the paper feed side U-shaped path 24 is adjacent to the paper feed roller 23 at the lower side, and the downstream side end is described later at the upper side so that the paper 3 is fed toward the front side. Adjacent to the conveyance belt 168, it is formed as a conveyance path for the substantially U-shaped sheet 3 such that the sheet 3 is discharged toward the back side.

  The paper 3 fed toward the front side by the paper feed roller 23 at the upstream end of the paper feed U-shaped path 24 is transported by the transport roller 25 in the paper feed U-shaped path 24. The sheet is conveyed, the conveyance direction is reversed, and after registration, the sheet is discharged toward the back side by the registration roller 26.

  The image forming unit 5 includes a process unit 27, a transfer unit 28, and a fixing unit 29. The process unit 27 is provided for each color of a plurality of colors of toner. In other words, the process unit 27 includes four units, that is, a yellow process unit 27Y, a magenta process unit 27M, a cyan process unit 27C, and a black process unit 27K. These process units 27 are arranged in the respective process accommodating units 12 of the main casing 2 and are sequentially arranged in parallel so as to be overlapped in the horizontal direction at intervals from the front side to the back side.

  Each process unit 27 includes a scanner unit 30, a drum cartridge 31 as a photosensitive cartridge, and a developing cartridge 32 that is detachably attached to the drum cartridge 31. The drum cartridge 31 and the developing cartridge 32 attached to the drum cartridge 31 constitute a process cartridge.

  The scanner unit 30 includes a scanner casing 35, and a laser light emitting unit (not shown), a polygon mirror 36, two lenses 37 and 38, and a reflecting mirror 39 in the scanner casing 35.

  As shown in FIG. 17, the scanner casing 35 is disposed at the center in the width direction of each partition plate 10 such that each rail portion 17 faces the scanner casing 35 across the width direction. The rear wall is in contact with the front surface of the partition plate 10, and the front wall 34 of the scanner casing 35 is provided on each partition plate 10 so as to bulge from the partition plate 10 toward the front side. Thus, since the scanner casing 35 is arranged so as to bulge from the partition plate 10 toward the front side, the scanner unit 30, the drum cartridge 31, and the developing cartridge 32 can be arranged close to each other. . Therefore, the apparatus can be reduced in size.

  In addition, since the scanner casing 35 is arranged so as to bulge from the partition plate 10 toward the front side, in the state where the developing cartridge 32 is attached to the drum cartridge 31 in the developing container 14, In a state in which the passage of the drum cartridge 31 in the developing container 14 is restricted and the developing cartridge 32 is separated from the drum cartridge 31, the drum cartridge 31 is allowed to pass through the developing container space 16 in the developing container 14. It becomes like this.

  That is, as shown in FIG. 18, the developing container 14 is moved by the scanner casing 35 in a direction orthogonal to the mounting direction and the width direction of the drum cartridge 31 and the developing cartridge 32 (the thickness of the mounted drum cartridge 31 and the developing cartridge 32. In the vertical direction, hereinafter simply referred to as “thickness direction”), it is formed narrower than the drum accommodating portion 13.

  Further, both the widthwise sides and the upper side of the scanner casing 35 in the developing container 14 and the vicinity of the front wall 34 of the scanner casing 35 (between the front wall 34 of the scanner casing 35 and the developing container space 16, which will be described later) In the space in which the plate 54 is disposed, an extension portion accommodation space 18 in which an extension portion 44 (described later) of the drum cartridge 31 is accommodated is formed.

Further, as shown in FIG. 1, an emission window 40 for emitting laser light is opened in the front wall 34 of the scanner casing 35.

  In the scanner unit 30, the laser light based on the image data emitted from the laser light emitting unit is reflected by the polygon mirror 36, and sequentially passes or reflects through the lens 37, the reflecting mirror 39, and the lens 38, and the exit window 40. It is emitted from.

  As shown in FIGS. 2 and 3, the drum cartridge 31 includes a drum casing 41, a photosensitive drum 42 as a photosensitive member provided in the drum casing 41, and a scorotron charger 62 (see FIG. 1). ing.

  The drum casing 41 includes a holder portion 43 and an extending portion 44 extending from the holder portion 43, and is integrally formed from a resin material.

  In the description of the drum cartridge 31 with reference to FIGS. 2 to 7, in the state where the drum cartridge 31 is mounted, the side located on the back side in the thickness direction of the drum cartridge 31 is referred to as “top side”, and the front side. The side positioned on the side is referred to as “bottom side”, the downstream side in the mounting direction of the drum cartridge 31 is referred to as “front side”, and the upstream side in the mounting direction of the drum cartridge 31 is referred to as “rear side”.

  The holder portion 43 includes two holder side walls 45 that are opposed to each other with a gap in the width direction, a holder ceiling wall 46 that is installed on the upper end of each holder sidewall 45, and each holder from the front end portion of the holder ceiling wall 46. A holder front wall 47 provided halfway in the thickness direction of the side wall 45 is provided.

  Note that the holder portion 43 is formed to be thicker than the developing housing 64 of the developing cartridge 32.

  Further, the thickness of the holder portion 43 is formed to be thicker than the thickness of the extending portion 44. By forming the holder portion 43 to be thicker than the extending portion 44, the photosensitive drum 42 and the scorotron charger 62 can be reliably accommodated.

  As shown in FIGS. 6 and 7, each holder side wall 45 is formed with a substantially U-shaped development positioning groove 48 opened rearward on the bottom side portion thereof. Further, an insertion portion 49 through which the drum shaft 60 of the photosensitive drum 42 is inserted is formed in front of the development positioning groove 48.

As shown in FIG. 2, the holder ceiling wall 46 is formed with a cleaner fitting portion 50 in which a cleaner 63 described later is slidably fitted over the width direction.
Further, as shown in FIGS. 6 and 7, at both ends in the width direction of the holder ceiling wall 46, horn portions 51 having a substantially triangular shape in a side view projecting to the top surface side are formed at the front end portion, respectively.

  As shown in FIGS. 2 and 3, the extending portion 44 extends above the upper end portion of the scanner casing 35 in the developing housing portion 14 in a state where the holder portion 43 is attached to the drum housing portion 13. In addition, it extends rearward from the holder portion 43.

  The extending portion 44 includes two extending side portions 52 that are opposed to each other with an interval in the width direction, an extending rear wall 53 that is installed at the rear end portion of each extending side portion 52, and a holder portion 43. And an intermediate plate 54 provided at a portion surrounded by each extended side portion 52 and the extended rear wall 53.

As shown in FIG. 2, each extending side portion 52 has a substantially U-shaped cross-section with the bottom surface open, and each outer surface continuously extends from the top surface side of the development positioning groove 48 of each holder side wall 45. The holder portion 43 is formed so as to extend rearward from both sides in the width direction so as to extend rearward.

  Further, as shown in FIG. 3, each extension side portion 52 is provided with two reinforcing ribs 55 along the front-rear direction inside the U-shaped inside as a reinforcing portion that is substantially X-shaped when viewed from the bottom. It has been.

  In addition, a drum boss portion 56 that protrudes outward in the width direction is provided on the outer surface of each extending side portion 52 in the middle of the longitudinal direction.

  The extended rear wall 53 extends along the width direction so as to connect the rear end portions of the extended side portions 52, and the drum cartridge 31 is gripped at the center portion in the width direction. A drum handle 57 for operating the attachment / detachment with respect to the accommodating portion 13 is provided.

  The intermediate plate 54 has a substantially rectangular flat plate shape in a plan view, and as shown in FIG. 2, each extended side portion 52 is surrounded by the holder portion 43, each extended side portion 52, and the extended rear wall 53. And it is provided so that it may connect with the holder part 43, each extension side part 52, and the extension rear wall 53 in the position dented from the top | upper surface side surface of the extension rear wall 53 to the bottom face side.

  The middle plate 54 is formed with an opening 58 for allowing laser light emitted from the emission window 40 of the scanner casing 35 to pass therethrough. As shown in FIG. 4, the opening 58 is formed in a trapezoidal shape in plan view with a wide front side and a narrow rear side.

  As shown in FIG. 2, the photosensitive drum 42 is accommodated in the holder portion 43 along the width direction. The photosensitive drum 42 has a cylindrical shape, and a drum main body 59 formed by a positively chargeable photosensitive layer whose outermost layer is made of polycarbonate or the like, and an axial center of the drum main body 59 along the axial direction of the drum main body 59. And a drum shaft 60 extending in the direction. The drum shaft 60 is supported at each holder side wall 45 so as not to rotate so that both end portions in the axial direction are inserted into the insertion portions 49 of the holder side walls 45 and protrude outward in the width direction of the holder side walls 45. .

  At both ends in the axial direction of the drum main body 59, rotation support members 61 are fitted so as not to be relatively rotatable, and each rotation support member 61 is supported around the drum shaft 60 so as to be relatively rotatable. Thereby, the drum main body 59 is rotatably supported with respect to the drum shaft 60. In this state, as shown in FIG. 5, the photosensitive drum 42 is arranged in the holder portion 43 so that the front surface is exposed from the bottom surface side of the holder front wall 47.

  As shown in FIG. 1, the scorotron charger 62 is accommodated in the holder portion 43 along the width direction above the horn portion 51. The scorotron charger 62 is a positively charged scorotron charger that includes a wire and a grid and generates corona discharge. The scorotron charger 62 is supported by a holder ceiling wall 46 behind the photosensitive drum 42. So as not to contact with each other. Further, as shown in FIG. 2, the scorotron charger 62 is provided with a cleaner 63 for cleaning the wire so as to be slidably fitted to the cleaner fitting portion 50 of the holder ceiling wall 46. ing.

  As shown in FIGS. 8 and 16, the developing cartridge 32 includes a developing housing 64, an agitator 69, a supply roller 66, a developing roller 67 as a developer carrier, and a layer thickness provided in the developing housing 64. And a regulating blade 68.

In the description of the developing cartridge 32 with reference to FIGS. 8 to 16, in the state in which the developing cartridge 32 is mounted, the side positioned on the back side in the thickness direction of the developing cartridge 32 is referred to as the “top side”, and the front side. The side positioned on the side is referred to as “bottom side”, the downstream side in the mounting direction of the developing cartridge 32 is referred to as “front side”, and the upstream side in the mounting direction of the developing cartridge 32 is referred to as “rear side”.

  As shown in FIG. 8, the developing housing 64 is formed as a thin box shape whose front side is opened. As shown in FIG. 15, the developing case 64 is separated from the box member 70 whose top side is opened, and the box member 70. And a lid member 71 that is formed of a body and closes the top surface of the box member 70 that is opened.

  The box member 70 is surrounded by a pair of side walls 72 that are arranged to face each other at intervals along the width direction, a rear wall 73 that connects the rear ends of the side walls 72, and the side walls 72 and the rear wall 73. Each side wall 72 and a bottom wall 74 connected to the bottom side end of the rear wall 73 are integrally provided so as to cover the portion to be covered.

  As shown in FIG. 14, the pair of side walls 72 has a flat plate shape extending in the front-rear direction, and integrally includes a front side wall 75, an inclined wall 76, and a rear side wall 77 so as to be continuous in the front-rear direction.

  Each front side wall 72 extends partway in the front-rear direction from the front end edge, and is at both ends of the developing roller 67, the layer thickness regulating blade 68, the supply roller 66, and the agitator 69, and in the front position sandwiching them, the front-rear facing distance Are arranged in parallel so that they are equal to each other.

  Each rear side wall 77 extends from the rear end edge to the middle in the front-rear direction (in the front-rear direction halfway from the rear end edge of each front side wall 72 in the front-rear direction), and on the opposite side of the developing roller 67 from the agitator 69. In the rear position, they are arranged in parallel so that the opposing distances in the front-rear direction are equal to each other at an opposing distance longer than the opposing distance between the front side walls 72.

  Each inclined wall 76 is disposed between the front wall 72 in the front-rear direction so that each front end edge is continuous with each front side wall 72 and each rear end edge is continuous with each rear side wall 77. It is inclined and arranged so as to gradually become longer from each front end edge toward each rear end edge. As shown in FIG. 15, the inner wall surface of each inclined wall 76 is an inclined surface 178 for guiding the discharge of toner. Even if the facing distance between the front side walls 75 is shorter than the facing distance between the back side walls 77 by the inclined surfaces 178, there is no step between them, and the toner is not retained between them. It can be smoothly guided and discharged from a toner storage chamber 92 described later.

  Further, as shown in FIG. 9, a developing boss portion 95 protruding outward in the width direction is provided on the rear end top surface side of the rear side wall 77 of each side wall 72.

  Further, as shown in FIGS. 9 and 15, the rear wall 73 is formed in an elongated rectangular plate shape extending in the width direction.

  As shown in FIG. 16, the bottom wall 74 has a flat plate shape, and the front wall (that is, the upstream portion in the mounting direction of the developing cartridge 32 facing each front wall 75) has an agitator 69. A discharge wall 78 that protrudes in a circular arc shape toward the top surface, a supply roller housing wall 79 that curves in a circular arc shape along the outer diameter of the supply roller 66, and a developing roller 67 so as to correspond to the rotation trajectory. And a tongue wall 80 that inclines toward the front side of the oblique bottom surface that exposes.

Further, as shown in FIG. 14, the outer wall surface of the bottom wall 74 has a front position and a rear position from a rear position (that is, a downstream portion in the mounting direction of the developing cartridge 32 facing each rear side wall 77). A bottom side grip 96 for indicating the grip region of the user is provided at the center in the width direction between the gaps (that is, in the middle of the mounting direction of the developing cartridge 32 facing each inclined wall 76). The bottom side grip portion 96 is formed of an uneven portion formed in a substantially rectangular shape when viewed from the bottom, and is provided as a mark so that the user can easily grip the developing cartridge 32.

  As shown in FIG. 9, contact projections 94 that protrude small toward the bottom surface are formed on the outer wall surface of the bottom wall 74.

  Further, as shown in FIG. 15, the inner wall surface of the bottom wall 74 is provided with a column member 81 that stands between the front position and the rear position and in the center in the width direction. Yes.

  This column member 81 is provided on the inner wall surface of the bottom wall 74 facing the bottom side grip portion 96 provided on the outer wall surface of the bottom wall 74, and as shown in FIG. As shown in FIG. 15, the width direction and the front-rear direction of the toner storage chamber 92 to be described later are spaced apart from each of the side walls 72, the rear wall 73, and the partition wall 83 to be described later. It is arranged at the center of the.

Moreover, this support | pillar member 81 is formed in the cylindrical shape of cross-sectional substantially bowl shape, and the one side edge part made into the taper shape of the substantially cross-section hook shape is arrange | positioned in the back side, and the round bottom of the substantially cross-section hook shape It is provided so that the other side edge part made into a shape may be arrange | positioned at the front side.
Then, at both end portions arranged on the rear side, both substantially V-shaped tapered surfaces formed in a tapered shape guide the toner in the discharging direction (downward in the mounted state of the developing cartridge 32). A guide surface 82 is provided. Since the guide surface 82 can smoothly guide the toner toward the downstream side in the discharge direction, it is possible to prevent the toner from being caught by the reinforcing column 65 and staying there.

  Further, a partition wall 83 provided between the front side walls 75 is provided midway in the front-rear direction of each front side wall 75 as shown in FIG.

  The partition wall 83 has an elongated rectangular plate shape extending in the width direction, is provided from the top surface side edge of each front side wall 75 to the middle in the thickness direction, and protrudes toward the top surface side. It is formed so as to face the connecting portion between the portion and the rear end portion of the supply roller accommodating wall 79 with a gap in the thickness direction.

  A discharge port 84 extending in the width direction is formed between the bottom end of the partition wall 83 and the connecting portion between the front end of the discharge wall 78 and the rear end of the supply roller accommodating wall 79. Is formed.

  In this box member 70, the top surface side edge of each side wall 72, the top surface side edge of the partition wall 83, and the top surface side edge of the rear wall 73 are as shown in FIG. A collar portion 85 for contacting the peripheral edge portion of the lid member 71 is formed.

  The lid member 71 has a substantially flat plate shape corresponding to the space surrounded by the partition wall 83, the side walls 72, and the rear wall 73, and the peripheral edge thereof is in contact with the flange portion 85 of the box member 70 and is formed flush with each other. The abutting portion 86 and the top wall 87 surrounded by the abutting portion 86 and formed so as to be recessed toward the top surface side are integrally provided.

  The ceiling wall 87 has a narrow rectangular flat plate-shaped front ceiling wall 88 that is opposed to the front position, a wide rectangular flat plate-shaped rear ceiling wall 89 that is opposed to the rear position and is deeper than the front ceiling wall 88, and A substantially trapezoidal flat plate shaped central wall 90 provided between them in the front-rear direction is integrally provided.

On the outer wall surface of the ceiling wall 87, a ceiling-side grip 97 is provided from the rear ceiling wall 89 to the middle ceiling wall 90, as shown in FIG. .
The top gripping portion 97 is composed of an uneven portion formed in a substantially rectangular shape in plan view, and is provided as a mark so that the user can easily grip the developing cartridge 32.

Further, as shown in FIG. 15, the inner wall surface of the top wall 87 is provided with a fitting cylinder portion 91 that fits the top surface side end of the column member 81 at the center in the width direction of the middle ceiling wall 90. ing.
The fitting cylinder portion 91 is provided on the inner wall surface of the ceiling wall 87 facing the ceiling gripping portion 97 provided on the outer wall surface of the ceiling wall 87, and as shown in FIG. In this way, the rear ceiling wall 89 is formed so as to protrude longer than the depression distance with respect to the contact portion 86. In addition, the fitting tube portion 91 has a cross-sectional shape that is slightly larger than the cross-sectional shape of the column member 81 and is substantially cylindrical, so that the fitting tube portion 91 can be fitted. It is formed in a shape. In addition, a guide surface 82 is formed in the fitting tube portion 91 corresponding to the guide surface 82 of the support column 81.

  The developing casing 64 is welded by covering the box member 70 with the lid member 71, bringing the abutting portion 86 of the lid member 71 into contact with the flange 85 of the box member 70, and welding the top of the column member 81. It is formed by inserting the surface side end portion into the fitting tube portion 91 and fitting it.

  The developing case 64 is formed in a thin shape in which the bottom side grip part 96 and the top side grip part 97 are arranged to face each other in the thickness direction, and the user can select the bottom side grip part 96 and the top side grip part 97. Can be held and held with one hand.

  In addition, since the support member 81 is fitted into the fitting cylinder portion 91, the reinforcing column 65 provided between the bottom wall 74 and the top wall 87 is formed by the support member 81 and the fitting cylinder portion 91. It is formed. As a result, even if a stress in the compression direction acts between the top wall 87 and the bottom wall 74, the stress can be received by the reinforcing column 65. As a result, the rigidity of the toner storage chamber 92 described below can be improved.

  In such a developing case 64, the top wall 87, the bottom wall 74 of the portion including the top wall 87 and the discharge wall 78 that is disposed to be opposed to the top wall 87 in the thickness direction, are disposed therebetween. Each side wall 72 (that is, from the rear side wall 77 to the middle part in the front-rear direction of the front side wall 75), the rear wall 73, and the partition wall 83 form a toner storage chamber 92 as a developer storage section.

  Further, a bottom wall 74 including the supply roller housing wall 79 and the tongue wall 80 in front of the toner housing chamber 92 and each side wall 72 continuous with the front bottom wall 74 (that is, from the front edge of the front side wall 75 in the front-rear direction). The developing chamber 93 is formed by the intermediate wall) and the partition wall 83.

  In the toner storage chamber 92, the front ceiling wall 88 and the rear ceiling wall 89 are opposed to the bottom wall 74 so that the distance between the rear ceiling wall 89 and the bottom wall 74 is longer than the distance between the front ceiling wall 88 and the bottom wall 74. And arranged so as to be parallel to the bottom wall 74. Further, the middle ceiling wall 90 is disposed so as to incline toward the top surface from the front toward the rear with respect to the bottom wall 74.

  Further, in the toner storage chamber 92, a toner filling port 98 is formed on one of the rear side walls 77 as a filling port having a substantially circular shape in side view penetrating in the thickness direction.

  The toner filling port 98 is normally closed by a cap 165 as shown in FIG.

  Further, as shown in FIGS. 11 and 12, the toner storage chamber 92 has detection windows 100 through which detection light for detecting the remaining amount of toner stored in the toner storage chamber 92 passes. The front side wall 75 is formed so as to be opposed to each other in the width direction.

  Each detection window 100 is formed in a substantially oval shape in side view long in the front-rear direction by cutting out each front side wall 75 and fitting a transparent resin plate into the cut-out portion. By forming each detection window 100 in a substantially oval shape in a side view that is long in the front-rear direction, in a state where the developing cartridge 32 is mounted in the developing container 14 as described later, both the separated state and the contact state are provided. Therefore, the detection light passing point described later can be secured at two locations by allowing detection light of the optical sensor 182 described later to pass therethrough.

  The front end of each detection window 100 is in a state where the developing cartridge 32 is mounted in the developing container 14 (that is, a state where the toner in the toner container 92 has moved to the discharge port 84 side vertically below due to its own weight). The toner in the toner storage chamber 92 is disposed at a position where the detection light can pass when the toner cartridge is consumed up to the remaining amount to replace the developing cartridge 32.

  Further, the rear end portion of each detection window 100 is in a state in which the developing cartridge 32 is attached to the developing container 14 (that is, the toner in the toner container 92 has moved to the discharge port 84 side vertically below due to its own weight. In the state), the toner in the toner storage chamber 92 is not spaced from the front end of each detection window 100 in the vertical direction. When the remaining amount is slightly higher than the remaining amount to be replaced, it is arranged at a position where the detection light can pass.

  In addition, as shown in FIG. 16, each detection window 100 overlaps in the front-rear direction with the projection surface of the rotation locus of the stirring member 152 of the agitator 69 described below in the axial direction of the rotation shaft 151, and in the thickness direction. Are formed on the front side walls 75 so as to face each other in the width direction so as to overlap a rotation shaft 151 of the agitator 69 described below.

  In addition, the reinforcing column 65 is disposed behind the optical path so as not to be positioned on the optical path of the detection light that passes between the detection windows 100 that are opposed to each other in the width direction.

  The agitator 69 is disposed in the vicinity of the discharge port 84 in the toner storage chamber 92. The agitator 69 is provided with a rotation shaft 151 rotatably supported on each front side wall 75 and a lattice frame plate shape (see FIG. 15) that extends from the rotation shaft 151 in the radial direction. And a stirring member 152 of FIG. The agitator 69 is disposed in the vicinity of the discharge port 84 so that the stirring member 152 is rotationally driven along the discharge wall 78, and is within the projection plane of the rotation locus of the stirring member 152 in the axial direction of the rotating shaft 151. Further, as described above, each detection window 100 is arranged.

  Further, the reinforcing column 65 is disposed behind the agitator 69 so that it does not overlap the projection surface of the rotation locus of the stirring member 152 in the axial direction of the rotating shaft 151 and does not come into contact with the rotating stirring member 152. ing.

  As shown in FIG. 15, the toner filling port 98 is also arranged behind the agitator 69 so as to overlap the projection surface of the rotation locus of the stirring member 152 in the axial direction of the rotation shaft 151. .

  The toner storage chamber 92 stores toner as a developer for each color. That is, as toner in the toner storage chamber 92, for each process unit 27, yellow for the yellow process unit 27Y, magenta for the magenta process unit 27M, cyan for the cyan process unit 27C, and cyan for the black process unit 27K. A positively chargeable nonmagnetic one-component polymerized toner having a black color is accommodated.

  More specifically, as the toner for each color, a substantially spherical polymerized toner obtained by a polymerization method is used. The polymerization toner is a known polymerization such as a suspension polymerization of a styrene monomer such as styrene or an acrylic monomer such as acrylic acid, alkyl (C1 to C4) acrylate, or alkyl (C1 to C4) methacrylate. The main component is a binder resin obtained by copolymerization according to the method, and a toner base particle is formed by adding a colorant, a charge control agent, a wax, etc. to this, and further improves the fluidity. In order to achieve this, an external additive is added.

As the colorant, the above-mentioned yellow, magenta, cyan and black colorants are blended. Moreover, as a charge control agent, for example, an ionic monomer having an ionic functional group such as an ammonium salt and an ionic monomer such as a styrene monomer or an acrylic monomer can be copolymerized. A charge control resin obtained by copolymerization with a monomer is blended.
As external additives, for example, powders of metal oxides such as silica, aluminum oxide, titanium oxide, strontium titanate, cerium oxide and magnesium oxide, inorganic powders such as carbide powders and metal salt powders are blended. Has been.

  As shown in FIG. 16, the developing chamber 93 is adjacently disposed in front of the toner storage chamber 92 so as to communicate with the toner storage chamber 92 via the discharge port 84.

  The developing chamber 93 is formed with an opening 159 that is open from the top surface to the front.

  Further, in the developing chamber 93, as shown in FIG. 8, the front end portion of the tongue wall 80 is disposed so as to be in pressure contact with the peripheral surface of the developing roller 67 from the bottom surface side in order to prevent toner leakage. The jaw portion 153 is formed over the entire width direction.

  Further, as shown in FIGS. 11 and 12, the front end portion of each front side wall 75 facing the jaw portion 153 in the width direction protrudes from the front side to the bottom surface side of the jaw portion 153 in a side view. In addition, a curved substantially L-shaped warped portion 154 is formed.

  As shown in FIG. 16, the supply roller 66 is disposed in front of the discharge port 84 in the developing chamber 93, and is provided along the width direction so as to be stored in the supply roller storage wall 79.

  The supply roller 66 includes a metal supply roller shaft 155 that is rotatably supported on each front side wall 75, and a supply roller layer 156 made of a conductive sponge member that covers the periphery of the supply roller shaft 155. ing.

  In the developing chamber 93, the developing roller 67 is disposed in front of the supply roller 66 obliquely on the top surface side, and is provided along the width direction so as to face the tongue wall 80. The developing roller 67 includes a metal developing roller shaft 157 rotatably supported on each front side wall 75 and a developing roller layer 158 made of a conductive rubber member that covers the periphery of the developing roller shaft 157. ing. More specifically, the developing roller layer 158 is coated with an elastic roller layer made of conductive urethane rubber, silicone rubber, EPDM rubber or the like containing carbon fine particles, and the surface of the roller layer. It has a two-layer structure with a coat layer mainly composed of urethane resin, polyimide resin or the like.

Further, the developing roller 67 is disposed so as to be in pressure contact with the supply roller 66, and as shown in FIG. 8, the front surface of the developing chamber 93 is exposed from the opening 159 as shown in FIG. The exposed bottom face side end portion is in pressure contact with the jaw portion 153 as described above.

  The layer thickness regulating blade 68 is provided on the entire front surface of the partition wall 83 in the width direction. As shown in FIG. 16, the layer thickness regulating blade 68 includes a blade 160 made of a metal leaf spring member, and a fixing member that clamps the top surface side end of the blade 160 and fixes the blade 160 to the front wall surface of the partition wall 83. 161 and a pressing portion 162 having a semicircular cross section made of insulating silicone rubber provided at the bottom side end portion of the blade 160. The layer thickness regulating blade 68 is provided in the bottom surface side end portion thereof, while the blade 160 is disposed in the thickness direction, and the top surface side end portion is fixed to the front wall surface of the partition wall 83 by the fixing member 161. The pressing portion 162 is provided so as to press the developing roller layer 158 of the developing roller 67 from the rear side by the spring force of the blade 160.

  As shown in FIGS. 8 and 11, the developing cartridge 32 includes an agitator drive gear (not shown) provided at the end of the rotating shaft 151 protruding from the outer wall surface of the one side wall 72, and the outer side of the one side wall 72. A supply roller driving gear (not shown) provided at the end of the supply roller shaft 155 protruding from the wall surface, and a developing roller driving gear (not shown) provided at the end of the developing roller shaft 157 protruding from the outer wall surface of one side wall 72 are provided. A gear train (not shown) for transmitting the driving force and a coupling female portion 163 for inputting the driving force to the gear train are provided on the outer wall surface of the front side wall 75 of the one side wall 72. The gear train and the coupling female portion 163 are held by the gear cover 164 in a gear cover 164 provided on the outer wall surface of the front side wall 75.

  The gear cover 164 is formed with a cover detection hole 179 having a substantially elliptical shape in side view corresponding to the one detection window 100 and extending in the front-rear direction at a position facing the one detection window 100 in the width direction.

  In the main casing 2, each process accommodating portion 12 is formed with a guide groove 101 through which the drum shaft 60 of the drum cartridge 31 is inserted in order to guide the attachment / detachment of the drum cartridge 31, as shown in FIG. 17. ing. The guide groove 101 is provided in the left side plate 8 and the right side plate 9 so as to be opposed to each other so as to be recessed outward in the width direction, and along the attaching / detaching direction of the drum cartridge 31 so as to be inclined rearward from the upper side to the lower side. Is arranged.

The lower end portion (deepest portion) of each guide groove 101 is a receiving portion 102 that receives the drum shaft 60 (FIG. 18).
See). The receiving portion 102 is formed in a concave shape in which the drum shaft 60 just fits in the front-back direction, and is arranged so that the photosensitive drum 42 and a conveyance belt 168 described later come into contact when the drum shaft 60 abuts. Yes.

  A drum positioning groove 103 is formed in the middle of each guide groove 101 in the longitudinal direction. The drum positioning groove 103 is recessed in a rectangular shape when viewed from the side. The drum positioning grooves 103 are formed at positions facing the left side plate 8 and the right side plate 9 in the width direction so that the drum boss portion 56 can be received.

  A boss insertion groove 133 into which the developing boss portion 95 of the developing cartridge 32 is inserted is formed above each guide groove 101 so as to cut out the left side plate 8 and the right side plate 9. The boss insertion groove 133 extends from the upper end of the left side plate 8 and the right side plate 9 in the attaching / detaching direction of the developing cartridge 32, more specifically, when the developing cartridge 32 is attached / detached, Along the moving path, it is formed so as to be cut out in a straight U-shape on the oblique back side.

Further, as shown in FIGS. 22 and 23, a light emitting unit 180 and a light receiving unit 181 are respectively provided on the inner side surface of the left side plate 8 and the inner side surface of the right side plate 9, and these light emitting unit 180 and light receiving unit 181 are provided. Thus, an optical sensor 182 as a developer amount detecting means for detecting the remaining amount of toner in the toner storage chamber 92 of the developing cartridge 32 is configured.

  The light emitting unit 180 and the light receiving unit 181 are disposed to face each other across the developing container 14 of the developing cartridge 32 in the width direction.

  More specifically, the light emitting unit 180 and the light receiving unit 181 are both in a separated state, which will be described later, of the developing cartridge 32 shown in FIG. 22 and a contact state, which will be described later, of the developing cartridge 32 shown in FIG. In this state, they are arranged so as to face each detection window 100 in the width direction.

  Further, in the up-down direction (vertical direction), each detection window in the width direction in both the separated state of the developing cartridge 32 shown in FIG. 23 and a contact state of the developing cartridge 32 shown in FIG. 100 is arranged to face 100.

  More specifically, the light emitting unit 180 and the light receiving unit 181 are arranged at the lower end of each detection window 100 (the developing cartridge 32 is accommodated in the developing accommodating portion 14) in the separated state of the developing cartridge 32 shown in FIG. 25 in the contact state described later of the developing cartridge 32 shown in FIG. 25, the upper end portion of each detection window 100 (the upper end portion when the developing cartridge 32 is accommodated in the developing accommodating portion 14). ).

  The light emitting unit 180 is made of a light emitting element, and enters the other detection window 100 with light having high directivity such as a laser as detection light. The light receiving unit 181 includes a light receiving element, and receives detection light emitted from one detection window 100.

  Further, as shown in FIG. 19, the left side plate 8 and the right side plate 9 are provided with a contact / separation mechanism 106 as a contact / separation means for contacting / separating the developing cartridge 32 with respect to the drum cartridge 31.

  The contact / separation mechanism 106 is provided in the vicinity of the boss insertion groove 133 on the outer surface of the left side plate 8 and the right side plate 9, and a first pressing member 116 that presses the developing boss portion 95 in the mounting direction, A first urging spring 117 that urges the first pressing member 116, a second pressing member 118 that presses the developing boss portion 95 toward the separation direction, and a second urging spring 119 that urges the second pressing member 118. And a cam 120 opposed to the first pressing member 116 and the second pressing member 118.

  The first pressing member 116 has a substantially V shape in which one piece and the other piece are continuous via a bent portion. In the separated state, which will be described later, the one piece is disposed in parallel with the boss insertion groove 133. Are arranged along the straight direction. A boss contact portion 121 that contacts the developing boss portion 95 is formed at one end portion of the one piece so as to bend and extend from one end portion to the front side in the separated state. The lower surface of the boss contact portion 121 is formed as an upper pressing surface 134 that presses the developing boss portion 95 from above. When the upper pressing surface 134 is in contact with the developing boss portion 95, the pressing force pressing the developing boss portion 95 in the mounting direction and the developing boss portion 95 toward the front side edge of the boss insertion groove 133. It is formed so as to be in contact with the developing boss portion 95 at an angle so that the pressing force is simultaneously generated. A cam contact portion 122 that contacts the cam 120 is formed on the other end portion of the other piece as a protrusion protruding upward from the other end portion in the separated state.

The first pressing member 116 has a support shaft 123 provided with a bent portion protruding outward in the width direction from the rear of the lower end portion (deepest portion) of the boss insertion groove 133 on the outer surface of the left side plate 8 and the right side plate 9. It is supported rotatably. As a result, the boss contact portion 121 can move forward and backward from the boss insertion groove 133, that is, the movement path of the development boss portion 95, from the front and back direction, and the cam contact portion 122 can move forward and backward from the support shaft 123. On the opposite side, the cam 120 is provided so as to be freely separated from the lower side.

  In such an arrangement, the support shaft 123 is arranged on the downstream side in the mounting direction of the developing boss part 95 with respect to the boss contact part 121 of the first pressing member 116.

  The first urging spring 117 is a tension spring, and one end of the first urging spring 117 is provided so as to protrude from below the lower end portion (deepest portion) of the boss insertion groove 133 on the outer surface of the left side plate 8 and the right side plate 9. It is fixed to the fixed shaft 124. The other end is locked to the cam contact portion 122. As a result, the first pressing member 116 always moves in the direction (front) in which the boss contact portion 121 advances with respect to the movement path of the developing boss portion 95 by the biasing force of the first biasing spring 118 and the cam. The contact portion 122 is biased in a direction (upward) in the proximity of the cam 120.

  The second pressing member 118 has a substantially rectangular plate shape, and in the separated state, a boss contact claw portion 125 that protrudes obliquely toward the upper front side and contacts the developing boss portion 95 is provided on the front surface side of the upper end portion. . Further, in the separated state, a rotation restricting claw portion 126 that protrudes obliquely downward on the front side of the lower end portion and can come into contact with the first fixed shaft 124 is provided. In the separated state, a cam contact protrusion 127 that protrudes upward and contacts the cam 120 is provided on the back surface side of the upper end. In the separated state, a spring locking projection 128 that protrudes downward and locks the other end of the second urging spring 118 is provided on the back surface side of the lower end.

  The second pressing member 118 is supported by the support shaft 123 so as to be rotatable in the middle in the front-back direction, so that the boss contact claw portion 125 is developed more than the boss contact portion 121 of the first pressing member 116. At the downstream side of the mounting direction of the boss portion 95, the boss insertion groove 133, that is, in the middle of the moving path of the developing boss portion 95, is movable in the mounting direction and the detaching direction of the developing boss portion 95 in the moving path. The restricting claw portion 126 can be brought into and out of contact with the first fixed shaft 124, and the cam contact protrusion 127 can be brought into and out of contact with the cam 120 from the lower side on the opposite side of the boss insertion groove 133 with respect to the support shaft 123. Provided.

  The second urging spring 119 is formed of a tension spring, and one end of the second urging spring 119 is provided on the outer surface of the left side plate 8 and the right side plate 9 so as to protrude outward in the width direction from below the first fixed shaft 124. 129 is fixed. The other end is locked to the spring locking protrusion 128. As a result, the second pressing member 118 is always in the direction in which the boss contact claw portion 125 presses the developing boss portion 95 in the separating direction in the movement path of the developing boss portion 95 by the urging force of the second urging spring 119. (Upward), the direction in which the rotation restricting claw portion 126 approaches the first fixed shaft 124 (upward), and the direction in which the cam contact protrusion 127 moves away from the cam 120 (downward) is urged.

  Note that the spring constant of the second urging spring 119 is set to be smaller than the spring constant of the first urging spring 117.

  Further, as shown in FIG. 22, both the first pressing member 116 and the second pressing member 118 are rotatably supported on the support shaft 123, but the first pressing member 116 is supported by the second pressing member 118. It is arrange | positioned with respect to the width direction outer side. Further, the boss contact portion 121 of the first pressing member 116 is formed so as to bulge inward in the width direction, and the boss contact claw portion 125 of the second pressing member 118 swells outward in the width direction. It is formed to come out. Therefore, the upper pressing surface 134 of the boss contact portion 121 and the lower pressing surface 135 of the boss contact claw portion 125 are arranged so as to overlap in the moving direction of the developing boss portion 95.

  As shown in FIG. 19, the cam 120 is formed in a substantially fan shape, and is provided on the left side plate 8 and the right side plate 9 so as to protrude outward in the width direction from the rear side upper side of the support shaft 123 and is rotatably supported. The camshaft 130 is connected to the camshaft 130 so as not to be relatively rotatable. The cam 120 has a continuous arc-shaped contact surface 131 and a substantially V-shaped separation surface 132 that forms a central angle on the side opposite to the contact surface 131 with respect to the cam shaft 130 on the outer peripheral surface. Is formed.

  In the cam 120, the contact surface 131 and the separation surface 132 are selectively selected with respect to the cam contact portion 122 of the first pressing member 116 and the cam contact protrusion 127 of the second pressing member 118 by the rotation of the cam shaft 130. Opposite to.

  Although the developing cartridge 32 is mounted in the developing container 14, the contact surface 131 of the cam 120 is arranged so that the photosensitive drum 42 and the developing roller 67 are separated from each other during the non-image forming operation. Is in contact with the cam contact portion 122 of the first pressing member 116 and the cam contact protrusion 127 of the second pressing member 118 and pushes them downward.

  Thus, the first pressing member 116 is pulled in the separated state, and the first urging spring 117 is pulled, and the boss abutting portion 121 of the developing boss portion 95 is against the urging force of the first urging spring 117. It is rotated in a direction to retract with respect to the movement path.

  Further, in the second pressing member 118, the second urging spring 119 is compressed in the separated state, and the boss contact claw portion 125 becomes the developing boss portion with a pressing force larger than the urging force of the second urging spring 119. The rotation restricting claw portion 126 is rotated in the direction in which the 95 is pressed in the disengagement direction and in the direction in which the rotation restricting claw portion 126 comes close to the first fixed shaft 124. In this separated state, the boss contact claw portion 125 is disposed on the upstream side in the mounting direction of the development boss portion 95 with respect to the contact state described later in the movement path of the development boss portion 95.

  In the contact / separation mechanism 106, as shown in FIG. 26A, a cam shaft 130 is installed between the left side plate 8 and the right side plate 9 for each process accommodating portion 12, and the left side plate 8 and the right side plate 9 9, the cam 120 is connected to both ends of the cam shaft 130 as a pair. In addition, although not shown, the first pressing member 116 and the second pressing member 118 are provided as a pair corresponding to the pair of cams 120 for each process accommodating portion 12.

  In the left side plate 8, cam drive gears 136 are connected to the end portions of the cam shafts 130 protruding outside the left side plate 8 so as not to rotate relative to each other, and between the cam drive gears 136. An intermediate gear 137 that meshes with each adjacent cam drive gear 136 is provided. As a result, as shown in FIG. 26 (b), the driving force is input from the motor 138 via the pinion gear 109 to the gear train constituted by the cam driving gears 136 and the intermediate gears 137. A driving force is input to each camshaft 130 via the row, and each camshaft 130 is rotated, so that the pair of cams 120 are simultaneously rotated, and the cam contact portions of the pair of first pressing members 116 The contact surfaces 131 and the separation surfaces 132 of the pair of cams 120 are selectively opposed to the cam contact protrusions 127 of the pair 122 and the pair of second pressing members 118.

  In this color laser printer 1, as shown in FIG. 18, in each process accommodating portion 12, first, the drum cartridge 31 for each color is mounted in the corresponding drum accommodating portion 13, thereby being attached to the main body casing 2. Each drum cartridge 31 is mounted, and then each developing cartridge 32 is mounted on each drum cartridge 31 mounted on the main casing 2 by mounting the developing cartridge 32 for each color in the corresponding developing container 14. Is done.

  More specifically, first, the drum handle 57 is operated, the drum boss portions 56 of the drum cartridge 31 are inserted into the guide grooves 101, and the drum cartridge 31 is pushed downward. As a result, the drum cartridge 31 is guided to pass through the developer accommodating portion 14 and then attached to the drum accommodating portion 13.

  When the holder portion 43 of the drum cartridge 31 passes through the developer accommodating space 16 of the developer accommodating portion 14, each horn portion 51 of the drum cartridge 31 faces each rail portion 17 of the developer accommodating portion 14 and is in the middle of mounting. Often rubbed against each other. Thus, if each horn part 51 and each rail part 17 are rubbed, a gap is formed between the front wall 34 of the scanner casing 35 and the holder ceiling wall 46, and these are rubbed against each other. Can be prevented.

  If each drum boss portion 56 is received in each drum positioning groove 103, the drum cartridge 31 is accommodated in the drum accommodating space 15, and the extending portion 44 is accommodated in the extending portion accommodating space 18 of the developer accommodating portion 14. Thus, the main body casing 2 is mounted.

  In the color laser printer 1, the front wall 34 of the scanner casing 35 is arranged so as to bulge out toward the developer accommodating space 16 in each process accommodating portion 12, and the drum cartridge 31 is provided in the developing accommodating portion 14. When the developing cartridge 32 is mounted, the passage of the drum cartridge 31 in the developing container 14 is restricted. However, in the developing container 14, the drum cartridge 31 is allowed to pass through the developing container space 16 when the developing cartridge 32 is separated from the drum cartridge 31.

  For this reason, the front wall 34 of the scanner casing 35 bulges toward the developing housing space 16, so that the drum cartridge 31 and the developing cartridge 32 can be easily attached to the drum cartridge 31 even if a space obtained by simply adding the attachment / detachment path of the developing cartridge 32 is not secured. 31 is separated from the developing cartridge 32 and passes through the developing housing space 16 of the developing housing space 16 without interfering with the front wall 34 of the scanner casing 35, and is attached to the drum housing portion 13 to be attached to the drum housing space 15. Can be accommodated. Then, as will be described later, the drum cartridge 31 and the developing cartridge 32 can be mounted if the developing cartridge 32 is mounted in the developing storage section 14 and stored in the developing storage area 16.

  In a state where the holder portion 43 is accommodated in the drum accommodating space 15 of the drum accommodating portion 13, each horn portion 51 gets over each rail portion 17 and is disposed below the scanner casing 35. The top surface side portion of the scorotron charger 62 is also disposed below the scanner casing 35. Further, the photosensitive drum 42 comes into contact with a conveyance belt 168 described later.

  Next, the bottom side grip portion 96 and the top side grip portion 97 of the developing cartridge 32 are gripped so as to be sandwiched by one hand, and each developing boss portion 95 is opposed to each boss insertion groove 133 as shown in FIG. The developing cartridge 32 is pushed downward. Then, each developing boss part 95 is inserted into each boss insertion groove 133 and comes into contact with each boss contact claw part 125 facing the moving path of each developing boss part 95 as shown in FIG. Each boss contact claw portion 125 is pressed toward the mounting direction by each developing boss portion 95, but since the cam contact portion 122 is in contact with the contact surface 131 of the cam 120, the second pressing member 118. Is restricted. Therefore, each developing boss portion 95 is further restricted from moving in the mounting direction, and stops at the contact position with each boss contact claw portion 125. As a result, the developing cartridge 32 is in contact with the drum cartridge 31. The photosensitive drum 42 and the developing roller 67 are held in a separated state with a gap therebetween. Thus, the developing cartridge 32 is accommodated in the developing accommodating space 16 of the developing accommodating portion 14 and is attached to the drum cartridge 31 attached to the main casing 2.

  In the laser printer 1, during the non-image forming operation, the developing cartridge 32 keeps such a separated state in which the photosensitive drum 42 and the developing roller 67 are separated from the drum cartridge 31, and during the image forming operation. The photosensitive drum 42 and the developing roller 67 are operated so as to be in contact with each other.

  That is, in the laser printer 1, in order to move the developing cartridge 32 from the separated state to the contact state, first, in the separated state, the contact surface 131 of the cam 120 is the cam contact portion 122 of the first pressing member 116. When the cam 120 is rotated from the state where it is in contact with the cam contact protrusion 127 of the second pressing member 118, the separation surface 132 of the cam 120 becomes the cam contact portion 122 of the first pressing member 116 and the second pressing member. The cam contact protrusions 118 are opposed to each other.

  In order to rotate each cam 120, as shown in FIG. 26, the motor 138 drives each camshaft 130 via a pinion gear 139 and a gear train composed of each cam drive gear 136 and each intermediate gear 137. A force is input to rotate each camshaft 130. As a result, the pair of cams 120 are simultaneously rotated, and the pair of cams is opposed to the cam contact portion 122 of the pair of first pressing members 116 and the cam contact protrusion 127 of the pair of second pressing members 118. 120 spaced surfaces 132 face each other.

  When the separation surface 132 of the cam 120 is opposed to the cam contact portion 122 of the first pressing member 116 and the cam contact protrusion 127 of the second pressing member 118, as shown in FIG. The pressing force is released. Then, in the first pressing member 116, the first urging spring 117 is restored and contracted by itself, and the boss abutting portion 121 becomes the developing boss portion with the supporting shaft 123 as a fulcrum by the urging force of the first urging spring 117. It is rotated in the direction of further advancement with respect to 95 movement paths. Further, the second pressing member 118 extends and is restored by the second urging spring 119, and the boss force is applied to the second urging spring 119 in the movement path of the developing boss portion 95 with the support shaft 123 as a fulcrum. The contact claw portion 125 is rotated in the direction toward the downstream side in the mounting direction of the developing boss portion 95 with respect to the separated state.

  Then, by the rotation of the first pressing member 116, the upper pressing surface 134 of the boss contact portion 121 contacts the developing boss portion 95, and the developing boss portion 95 is connected to the mounting boss portion 95 and the boss insertion groove 133. Press toward the front side edge. Further, the rotation of the second pressing member 118 moves the boss contact claw portion 125 to the downstream side in the mounting direction of the developing boss portion 95 with respect to the separated state. The side pressing surface 135 abuts on the developing boss portion 95 pressed by the upper pressing surface 134 of the boss abutting portion 121 and elastically receives the developing boss portion 95 by the urging force of the second urging spring 119. .

  Since the spring constant of the second urging spring 119 is set to be smaller than the spring constant of the first urging spring 117, the developing boss portion 95 is pushed from the upper pressing surface 134 of the boss contact portion 121. The pressure is moved to the downstream side in the mounting direction with respect to the separated state, and is received by the lower pressing surface 135 of the boss contact claw portion 125 in that state. Then, the developing roller 67 is brought into contact with the photosensitive drum 42 by the movement of the developing boss portion 95 toward the downstream side in the mounting direction, whereby the photosensitive drum 42 and the developing roller 67 are brought into contact with each other.

  Further, in this contact state, the developing boss portion 95 is brought into contact with the front side edge of the boss insertion groove 133 by the pressing force from the upper pressing surface 134.

In the contact state, the first pressing member 116 and the second pressing member 118 are urged by the first urging spring 117 and the second urging spring 119, respectively.
A gap is formed between the separation surface 132 of the first pressing member 116 and the cam contact portion 122 of the first pressing member 116 and the cam contact protrusion 127 of the second pressing member 118.

  Further, in the contact state, the light emitting unit 180 and the light receiving unit 181 face each detection window 100 of the developing cartridge 32 at the upper end of each detection window 100 as shown in FIGS.

  As will be described later, when the developing cartridge 32 moves from the separated state to the contact state, the remaining amount of toner is detected by the optical sensor 182, and the upper detection light passes from the light emitting unit 180, as will be described later. Detection light is emitted toward the light receiving unit 181 so as to pass through the upper end of each detection window 100 in the toner storage chamber 92 as a point.

  Further, in order to move the developing cartridge 32 from the contact state to the separation state, first, in the contact state, the separation surface 132 of the cam 120 has the cam contact portion 122 of the first pressing member 116 and the second pressing member 118. In the same manner as described above, the cam 120 is rotated from the state facing the cam contact protrusion 127 with a gap therebetween, so that the contact surface 131 of the cam 120 becomes the cam contact portion 122 of the first pressing member 116 and the first contact. 2 The state is brought into contact with the cam contact protrusion 127 of the pressing member 118.

  When the contact surface 131 of the cam 120 faces the cam contact portion 122 of the first pressing member 116 and the cam contact protrusion 127 of the second pressing member 118, as shown in FIG. Contacts the cam contact portion 122 of the first pressing member 116 and the cam contact protrusion 127 of the second pressing member 118, and pushes them downward. Then, in the first pressing member 116, the first urging spring 117 is pulled, and the boss abutting portion 121 has the developing boss portion with the support shaft 123 as a fulcrum against the urging force of the first urging spring 117. It is rotated in the direction of retreating with respect to 95 movement paths. Further, the second pressing member 118 is configured such that the second urging spring 119 is compressed, and a moving path of the developing boss portion 95 with the supporting shaft 123 as a fulcrum with a pressing force larger than the urging force of the second urging spring 119. , The boss contact claw portion 125 is rotated in the direction toward the upstream side in the mounting direction of the developing boss portion 95 with respect to the contact state.

  Then, the upper pressing surface 134 of the boss contact portion 121 is separated from the developing boss portion 95 by the rotation of the first pressing member 116. Further, by the rotation of the second pressing member 118, the boss contact claw portion 125 is moved to the upstream side in the mounting direction of the developing boss portion 95 with respect to the contact state. The side pressing surface 135 presses the developing boss portion 95 in the detaching direction. Then, the developing roller 67 is separated from the photosensitive drum 42 by the movement of the developing boss portion 95 toward the upstream side in the mounting direction, and thereby the photosensitive drum 42 and the developing roller 67 are separated from each other. In this separated state, the developing cartridge 32 can be detached from the developing container 14.

  In the separated state, the light emitting unit 180 and the light receiving unit 181 face each detection window 100 of the developing cartridge 32 at the lower end of each detection window 100 as shown in FIGS.

  As will be described later, when the developing cartridge 32 moves from the contact state to the separated state, the remaining amount of toner is detected by the optical sensor 182, and the lower detection light is emitted from the light emitting unit 180 as will be described later. Detection light is emitted toward the light receiving unit 181 so as to pass through the lower end of each detection window 100 in the toner storage chamber 92 serving as a passing point.

Further, as described above, when the developing roller 67 and the photosensitive drum 42 are brought into contact with each other during the image forming operation and the developing roller 67 and the photosensitive drum 42 are separated from each other during the non-image forming operation, the developing roller 67 and the photosensitive drum 42 are separated. Since the contact is made only when necessary, it is possible to prolong these lives.

  In the developing cartridge 32 attached to the drum cartridge 32, the developing roller shaft 157 of the developing roller 67 is positioned with respect to the drum housing 41 so that the developing container 14 can be selectively arranged in the separated state and the contact state. By fitting into the groove 48, the developing cartridge 32 is positioned with respect to the drum cartridge 32.

  Further, the abutment protrusion 94 of the bottom wall 74 of the developing housing 64 abuts on the back surface 33 of the partition plate 10, whereby the developing cartridge 32 is positioned with respect to the developing container 14.

  When the drum cartridge 31 is mounted in the drum accommodating portion 13, the photosensitive drum 42 is grounded by connection between contacts (not shown), and a charging bias is applied to the scorotron charger 62 during the image forming operation. Further, due to meshing of a gear (not shown), a driving force from the motor 138 is input during the image forming operation, and the photosensitive drum 42 is rotated.

  When the developing cartridge 32 is mounted in the developing container 14, a developing bias is applied to the developing roller shaft 157 of the developing roller 67 during an image forming operation due to connection between contacts (not shown). Further, due to the coupling of the coupling (not shown), the driving force from the motor 138 is input during the image forming operation, and the agitator 69, the supply roller 66, and the developing roller 67 are rotated.

  In each process unit 27, during the image forming operation, as shown in FIG. 1, in each developing cartridge 32, the toner for each color stored in the toner storage chamber 92 is discharged vertically downward by its own weight. It moves to the outlet 84 and is discharged from the outlet 84 while being stirred by the agitator 69.

  The toner discharged from the discharge port 84 is supplied to the supply roller 66. The toner supplied to the supply roller 66 is supplied to the development roller 67 by the rotation of the supply roller 66. At this time, the toner is positively frictionally charged between the supply roller 66 and the development roller 67 to which the development bias is applied. Is done.

  The toner supplied to the developing roller 67 enters between the pressing portion 162 of the layer thickness regulating blade 68 and the developing roller layer 158 of the developing roller 67 as the developing roller 67 rotates, and a thin layer having a constant thickness. Is carried on the surface of the developing roller layer 158.

  On the other hand, in the drum cartridge 31, the scorotron charger 62 generates a corona discharge by applying a charging bias to uniformly positively charge the surface of the photosensitive drum 42. The surface of the photosensitive drum 42 is uniformly positively charged by the scorotron charger 62 with the rotation of the photosensitive drum 42, and then exposed by high-speed scanning of laser light from the scanner unit 30 to form on the paper 3. An electrostatic latent image corresponding to the power image is formed.

  When the photosensitive drum 42 is further rotated, when the toner carried on the surface of the developing roller 67 and positively charged toner comes into contact with the photosensitive drum 42 by the rotation of the developing roller 67, the photosensitive drum 42. The electrostatic latent image formed on the surface, that is, the surface of the photosensitive drum 42 that is uniformly positively charged, is supplied to an exposed portion exposed to a laser beam and having a lowered potential. As a result, the electrostatic latent image on the photosensitive drum 42 is visualized, and a toner image by reversal development is carried on the surface of the photosensitive drum 42 for each color.

As shown in FIG. 1, the transfer unit 28 is disposed in the main casing 2 above the paper feed unit 4 and below each process storage unit 12 along the normal direction, and includes a driving roller 166 and a driven roller. A roller 167, a conveyance belt 168, and a transfer roller 169 are provided.

  The drive roller 166 is disposed on the front side of the process storage unit 12 in which the yellow process unit 16Y is stored. The driven roller 167 is disposed on the back side of the process storage unit 12 in which the black process unit 16K is stored.

  The conveyor belt 168 is made of an endless belt and is made of a resin such as conductive polycarbonate or polyimide in which conductive particles such as carbon are dispersed. The conveyor belt 168 is wound between the driving roller 166 and the driven roller 167.

  The driven roller 167 is driven by the driving roller 166, and the image forming position where the conveying belt 168 contacts the photosensitive drum 42 of each process unit 27 between the driving roller 166 and the driven roller 167. In FIG. 2, it is moved so as to rotate in the same direction as the photosensitive drum 42.

  Further, the transfer roller 169 faces the photosensitive drum 42 of each process unit 16 with the conveyance belt 168 interposed therebetween in the conveyance belt 168 wound between the driving roller 166 and the driven roller 167. Is provided. In this transfer roller 169, a metal roller shaft is covered with a roller layer made of an elastic member such as a conductive rubber material. Further, the transfer roller 169 is rotatably provided so as to rotate in the same direction as the circumferential movement direction of the transport belt 168 at an image forming position where the transfer roller 169 faces and contacts the transport belt 168. Is applied.

  Then, the sheet 3 fed from the sheet feeding unit 4 is conveyed from the front side to the back side by the conveyor belt 168 that is circulated by driving of the driving roller 166 and driven of the driven roller 167. The image forming position between the process unit 27 and the photosensitive drum 42 is conveyed so as to sequentially pass. During the conveyance, the toner images of the respective colors carried on the photosensitive drums 42 of the respective process units 27 are sequentially transferred. As a result, a color image is formed on the sheet 3.

  That is, for example, when a yellow toner image carried on the surface of the photosensitive drum 42 of the yellow process unit 27Y is transferred to the sheet 3, then the magenta toner carried on the surface of the photosensitive drum 42 of the magenta process unit 27M is transferred. The toner image is transferred onto the paper 3 on which the yellow toner image has already been transferred, and the cyan toner image carried on the surface of the photosensitive drum 42 of the cyan process unit 16C and the black process unit 16 are similarly operated. The black toner image carried on the surface of the photosensitive drum 42 is transferred in a superimposed manner, whereby a color image is formed on the paper 3.

  In the formation of such a color image, this color laser printer 1 is a tandem type apparatus in which a plurality of sets corresponding to different colors are provided in each process unit 27 with the drum cartridge 31 and the developing cartridge 32 as one set. Due to the configuration, it is possible to form a toner image for each color at a speed almost the same as a speed for forming a monochrome image, thereby achieving a rapid color image formation. Therefore, it is possible to form a color image while reducing the size.

  The fixing unit 29 is on the back side of the main casing 2 with respect to the process accommodating unit 12 in which the black process unit 16K is accommodated, and is opposed to the image forming position where the photosensitive drum 42 and the conveying belt 168 are in contact with each other in the normal direction. Are arranged to be. The fixing unit 29 includes a heating roller 170 and a pressure roller 171.

  The heating roller 170 is made of a metal base tube having a release layer formed on the surface thereof, and a halogen lamp is provided along the axial direction thereof. Then, the surface of the heating roller 170 is heated to the fixing temperature by the halogen lamp. The pressure roller 171 is provided so as to press the heating roller 170.

  The color image transferred onto the paper 3 is then conveyed to the fixing unit 29 and thermally fixed while the paper 3 passes between the heating roller 170 and the pressure roller 171.

  The paper discharge unit 6 includes a paper discharge side U-shaped path 172, a paper discharge roller 173 as a discharge unit, and a paper discharge tray 174.

  The discharge-side U-shaped path 172 has an upstream end adjacent to the fixing unit 29 at the lower side and a downstream end at the upper side so that the sheet 3 is fed toward the back side. Adjacent to 174, it is formed as a transport path for the substantially U-shaped sheet 3 so that the sheet 3 is discharged toward the front side.

  The paper discharge roller 173 is provided as a pair of rollers at the downstream end of the paper discharge side U-shaped path 172.

  The sheet discharge tray 174 is formed on the upper surface of the main casing 2 as an inclined wall that is inclined downward from the front side toward the back side.

  The sheet conveyed from the fixing unit 29 is fed toward the back side at the upstream end of the discharge side U-shaped path 172, and the conveyance direction is reversed in the sheet-feeding U-shaped path 84. The paper is discharged onto the paper discharge tray 174 by the paper discharge roller 173 toward the front side.

  In such an image forming operation, toner is consumed in each developing cartridge 32 corresponding to the color to be image-formed. On the other hand, the toner in the toner storage chamber 92 is moved to the discharge port 84 side in the vertical direction under its own weight when the developing cartridge 32 is mounted in the developing storage portion 14, and therefore is initially full as the toner consumption progresses. The toner level (water level) in the state gradually falls downward in the vertical direction. Eventually, the developing cartridge 32 has not reached the remaining amount to be replaced, but reaches the near empty level where the remaining amount is slightly higher than the remaining amount to be replaced.

  When the near empty level is reached, as will be described later, in the contact state of the developing cartridge 32 (see FIG. 25), the detection light emitted from the light emitting unit 180 passes through each of the toner storage chambers 92 which are upper detection light passage points described later. The upper end of the detection window 100 can be passed.

  Further, when the toner is consumed, the toner descends further downward in the vertical direction from the near empty level, and reaches the empty level where the remaining amount of the developing cartridge 32 is to be replaced.

  When the empty level is reached, as will be described later, the detection light emitted from the light emitting unit 180 in the separated state of the developing cartridge 32 (see FIG. 23), in each toner storage chamber 92 which is a lower detection light passage point described later. The lower end of the detection window 100 can be passed.

In this color laser printer 1, in each process unit 12, both the separated state of the developing cartridge 32 during the non-image forming operation and the contact state of the developing cartridge 32 during the image forming operation are detected by the optical sensor 182. Thus, the near empty level and the empty level are detected by the light emitting unit 180 and the light receiving unit 181 based on whether or not the detection light is detected through each detection window 100 of the toner storage chamber 92, and thereby the toner in the toner storage chamber 92 is detected. Judgment is made to determine the remaining amount.

  FIG. 27 is a block diagram illustrating a control system for determining the remaining amount of toner, and FIG. 28 is a flowchart of a remaining toner determination program for determining the remaining amount of toner.

  Next, control for determining the remaining amount of toner in the color laser printer 1 will be described with reference to FIGS. The control described below is performed individually (regardless of other developing cartridges 32) for each developing cartridge 32 in each process unit 12.

  In FIG. 27, a light emitting unit 180 and a light receiving unit 181 constituting the optical sensor 182 are connected to a CPU 183 as a determination unit.

  The CPU 183 includes a ROM 184 that stores various control programs, and a RAM 185 that stores temporary numerical values when the control programs are executed. The ROM 184 stores a toner remaining amount determination program for determining the remaining amount of toner.

  The CPU 183 inputs a light emission signal to the light emitting unit 180 and receives a light reception signal from the light receiving unit 181. The CPU 183 controls the optical sensor 182 to determine the presence or absence of toner in the toner storage chamber 92. That is, the CPU 183 inputs a light emission signal to the light emitting unit 180 at the detection timing of the optical sensor 182. In the light emitting unit 180, the detection light is incident on the other detection window 100 by the input of the light emission signal from the CPU 183. At this time, if the detection light passing through the toner storage chamber 92 is emitted from one detection window 100 and received by the light receiving unit 181, the light receiving unit 181 inputs a light reception signal to the CPU 183. The CPU 183 determines “no toner” based on the input of the received light signal. On the other hand, at this time, if the detection light passing through the toner storage chamber 92 is blocked by the toner in the toner storage chamber 92, the detection light is not emitted from one detection window 100 and is not received by the light receiving unit 181. Therefore, the light receiving unit 181 does not input a light reception signal to the CPU 183 and the CPU 183 determines that “toner is present” because no light reception signal is input.

  The CPU 183 is connected to a remaining toner amount display unit 186 as a notification unit. This toner remaining amount display portion 186 is provided on an operation panel (not shown) provided above the main body casing 2. The toner remaining amount display unit 186 includes an empty lamp 187 and a near empty lamp 188, and receives a first lighting signal and a second lighting signal from the CPU 183.

  The empty lamp 187 is lit at an empty level at which the toner in the toner storage chamber 92 is consumed up to the remaining amount to replace the developing cartridge 32 in response to the input of the first lighting signal from the CPU 183.

  The near-empty lamp 188 is lit at a near-empty level when the toner in the toner storage chamber 92 approaches the remaining amount for which the developing cartridge 32 should be replaced in response to the input of the second lighting signal from the CPU 183.

The CPU 183 is connected to a motor 138 for inputting a driving force to each cam 120 described above. The CPU 183 controls the driving of the motor 138 during image formation, and moves the developing cartridge 32 to the contact state by rotation of the cam 120, and controls the driving of the motor 138 during non-image formation to control the cam 120. Is rotated to move the developing cartridge 32 to the separated state.

  Next, with reference to FIG. 28, a description will be given of the determination process of the remaining amount of toner in the toner storage chamber 92 by the toner remaining amount determination program.

  In FIG. 28, the processing of the toner remaining amount determination program is triggered by the timing at which the developing cartridge 32 moves from the separated state to the contact state, such as when a print job is input to the CPU 183 or when an initial operation is started by the CPU 183. To be started. At the start of processing, the developing cartridge 32 is in a separated state.

  When the processing is started, first, the CPU 183 detects the optical sensor 182 in the separated state of the developing cartridge 32 shown in FIG. 23 (S1), and determines the presence or absence of toner (S2).

  When the detection of the optical sensor 182 is executed in the separated state of the developing cartridge 32, as shown in FIG. 20, from the light emitting unit 180, the lower end portion of each detection window 100 in the toner storage chamber 92 (hereinafter referred to as “lower detection”). The detection light is emitted toward the light receiving unit 181 so as to pass through the “light passage point”.

  When the light receiving unit 181 receives the detection light and determines that “no toner” (S2: NO), the CPU 183 inputs a first lighting signal to the empty lamp 187 to turn on the empty lamp 187. (S3), the process ends.

  That is, the lower detection light passing point is such that the toner in the toner storage chamber 92 replaces the developing cartridge 32 in a state where the toner in the toner storage chamber 92 has moved to the discharge port 84 side vertically below due to its own weight. It is arranged at a position where the detection light can pass at an empty level consumed up to the remaining power. Therefore, when the detection light emitted from the light emitting unit 180 passes through the lower detection light passing point and is received by the light receiving unit 181, the toner in the toner storage chamber 92 reaches the remaining amount to replace the developing cartridge 32. Since it is consumed, the empty lamp 187 is turned on to notify the user that the developing cartridge 32 should be replaced.

  On the other hand, if the light receiving unit 181 does not receive the detection light and it is determined that “toner is present” (S2: YES), the cam 120 is rotated by driving the motor 138 to move the developing cartridge 32 from the separated state to the contact state. (S4). Then, detection of the optical sensor 182 in the contact state of the developing cartridge 32 shown in FIG. 25 is executed (S5), and the presence or absence of toner is determined (S6).

  When the detection of the optical sensor 182 is executed in the contact state of the developing cartridge 32, as shown in FIG. 21, the upper end portion of each detection window 100 in the toner storage chamber 92 (hereinafter referred to as “upper detection light”), as shown in FIG. Detection light is emitted toward the light receiving unit 181 so as to pass through a “passing point”.

  Then, if the light receiving unit 181 receives the detection light and determines that “no toner” (S6: NO), the CPU 183 inputs a second lighting signal to the near empty lamp 188 and turns the near empty lamp 188 on. After lighting (S7), the print job is executed as it is (S8).

That is, the upper detection light passing point is such that the toner in the toner storage chamber 92 should replace the developing cartridge 32 in a state where the toner in the toner storage chamber 92 has moved to the discharge port 84 side vertically below due to its own weight. Although it has not reached the remaining amount, it is disposed at a position where the detection light can pass at a near empty level where the remaining amount is slightly higher than the remaining amount to be replaced. Therefore, when the detection light emitted from the light emitting unit 180 passes through the upper detection light passing point and is received by the light receiving unit 181, the toner in the toner storage chamber 92 is slightly more than the remaining amount to be replaced. Since the remaining amount is consumed, the near empty lamp 188 is turned on to notify the user that the replacement of the developing cartridge 32 is near and to alert the user.

  On the other hand, if the light receiving unit 181 does not receive the detection light and it is determined that “toner is present” (S6: YES), the CPU 183 does not input the second lighting signal to the near empty lamp 188, and the near empty lamp 188 The print job is executed without being lit (S8).

  That is, when the detection light emitted from the light emitting unit 180 does not pass through the upper detection light passage point and is shielded by the toner in the toner storage chamber 92, the toner in the toner storage chamber 92 is less than the near empty level. A large amount remains. Therefore, normal image formation can be ensured without alerting the user about the remaining amount of toner.

  After execution of the print job, the cam 120 is rotated by driving the motor 138 to move the developing cartridge 32 from the contact state to the separated state (S9), and the process is terminated.

  In such determination processing of the remaining amount of toner, the detection light emitted from the light emitting unit 180 passes through the upper detection light passing point and the lower detection light passing point and is received by the light receiving unit 181. Therefore, even if an abnormality occurs in one of the upper detection light passage point and the lower detection light passage point, resulting in a false detection, the other normal detection light passage point , Can be detected normally. As a result, accurate detection of the remaining amount of toner can be achieved.

  In the toner remaining amount determination process described above, the CPU 183 can determine the remaining amount of toner based on the respective light reception results obtained from the upper detection light passage point and the lower detection light passage point. . Therefore, the remaining amount of toner can be accurately determined. More specifically, the CPU 183, based on the upper detection light passage point and the lower detection light passage point, the light reception result corresponding to the upper detection light passage point and the light reception result corresponding to the lower detection light passage point, Since the remaining amount of toner is determined by combining these, the remaining amount of toner can be determined in detail.

  In the toner remaining amount determination process described above, when the remaining amount of toner reaches the near empty level corresponding to the remaining amount of toner, the near empty lamp 188 is turned on to reach the empty level. When this happens, the empty lamp 187 is turned on. Therefore, the user can recognize the remaining amount of toner based on the determination result of the remaining amount of toner of the CPU 183 accurately and stepwise.

  Further, in the above-described determination process of the remaining amount of toner, in the pair of detection windows 100, the detection light is emitted so that the upper end portion becomes the upper detection light passage point and the lower end portion becomes the lower detection light passage point. Since it is allowed to pass, the ratio of toner leakage from the detection window 100 compared to the case where two pairs of detection windows 100 are provided independently of each other corresponding to the upper detection light passage point and the lower detection light passage point. Can be reduced.

In addition, since the upper detection light passage point and the lower detection light passage point are spaced apart from each other in the vertical direction, an accurate toner remaining amount corresponding to the level of the toner that falls according to toner consumption can be obtained. Detection can be achieved. Therefore, the remaining amount of toner can be detected with higher accuracy.

  In the above-described toner remaining amount determination process, the upper detection light passage point and the lower detection light passage point are switched by the movement of the developing cartridge 32 between the separated state and the contact state. It is unnecessary to provide the optical sensors 182 corresponding to the points and the lower detection light passing points. Therefore, the apparatus configuration can be simplified and the cost can be reduced.

  In particular, the developing cartridge 32 is mounted on the developing container 14 in the diagonally up and down direction from the upper front side to the lower back side, and is separated along the mounting direction between non-image formation and image formation. Move between and the contact state. As the developer cartridge 32 moves in the diagonally up and down direction, the upper detection light passage point and the lower detection light passage point are consequently switched in the vertical direction, so that the height of the detection light can be increased with a simple configuration. Accuracy detection can be achieved.

  Further, as the developing cartridge 32 is moved by the contact / separation mechanism 106, the upper detection light passage point and the lower detection light passage point are switched, so that the upper detection light passage point and the lower detection light passage point are switched. Switching between the upper detection light passing point and the lower detection light passing point can be achieved at a low cost with a simple and reliable configuration without requiring any special switching means.

  Moreover, in the toner remaining amount determination process described above, the timing at which the developing cartridge 32 moves from the separated state to the contacted state as the contacting / separating mechanism 106 moves, that is, from the lower detection light passing point. At the timing of switching to the upper detection light passage point, the CPU 183 determines the remaining amount of toner. Therefore, the remaining amount of toner can be detected at an appropriate timing, and the remaining amount of toner can be detected with higher accuracy.

  In the above-described toner remaining amount determination process, the optical sensor 182 has a long hole when the developer cartridge 32 reaches the separated state and the contact state, that is, when the developer cartridge 32 reaches both ends in the vertical direction of the maximum movement range of the developer cartridge 32. The detection light is passed through the upper detection light passage point and the lower detection light passage point corresponding to the upper end portion and the lower end portion of the detection window 100 formed in the above, and the presence or absence of toner is detected. Therefore, it is possible to ensure a wide range in which the remaining amount of toner is detected. As a result, the remaining amount of toner can be detected appropriately.

  That is, in this developing cartridge 32, each detection window 100 is formed in an approximately oval shape when viewed from the side, and therefore it is easy to provide an upper detection light passage point and a lower detection light passage point with a simple configuration. In addition, in the state where the developing cartridge 32 is mounted in the developing container 14, the toner level is accurately detected because the developing cartridge 32 is formed in an approximately elliptical shape when viewed from the side. Therefore, the remaining amount of toner can be detected with higher accuracy.

  In addition, each detection window 100 is formed so as to face each front side wall 75 in the width direction. Therefore, the detection light is incident from the detection window 100 provided on the other side wall 75 to detect the detection light. Can be emitted from the detection window 100 provided on one side wall 75. Therefore, the remaining amount of toner in the toner storage chamber 92 can be accurately detected.

In the above description, the presence or absence of toner is detected by passing detection light at each of the upper detection light passage point and the lower detection light passage point by the processing of the toner remaining amount determination program. When 32 moves between the separated state and the contact state, the optical sensor 182 detects the presence or absence of toner continuously along the vertical direction between the upper end portion and the lower end portion of each detection window 100. Thus, the level of the remaining amount of toner in the toner storage chamber 92 can be displayed, for example, as a percentage.

  FIG. 29 is a block diagram showing a control system of a remaining toner amount display program as a reference example for executing such processing, and FIG. 30 is a flowchart of the remaining toner amount display program.

  29, the same members as those in FIG. 27 are denoted by the same reference numerals, and the description thereof is omitted.

  In FIG. 29, the toner remaining amount display unit 186 is provided with an empty level gauge lamp 189 instead of the above-described empty lamp 187 and near empty lamp 188. The empty level gauge lamp 189 displays the level of the remaining amount of toner in the toner storage chamber 92 as a percentage by inputting a level signal corresponding to the remaining amount of toner from the CPU 183.

  Next, display processing of the remaining amount of toner in the toner storage chamber 92 by the toner remaining amount display program will be described with reference to FIG.

  In FIG. 30, similar to the toner remaining amount determination program, the processing of the toner remaining amount display program is performed when the developing cartridge 32 comes into contact from a separated state, such as when a print job is input to the CPU 183 or when an initial operation is started by the CPU 183. It starts with the timing of moving to the state as a trigger. At the start of processing, the developing cartridge 32 is in a separated state.

  When the process is started, the CPU 183 first detects the optical sensor 182 in the separated state of the developing cartridge 32 shown in FIG. 23 (S11), and determines the presence or absence of toner (S12). If it is determined that there is no toner (S12: NO), the CPU 183 sends an empty level signal to the empty level gauge lamp 189 (corresponding to a specific percentage within the percentage range (empty level) where the developing cartridge 32 should be replaced). Level signal) is input, the empty level gauge lamp 189 displays a specific percentage of the empty level (S13), and the process ends.

  On the other hand, if it is determined that “toner is present” (S12: YES), the count of the timer incorporated in the CPU 183 is started (S14), and at the same time, detection of the optical sensor 182 is started (S15). Thereafter, the cam 120 is rotated by driving the motor 138, and the developing cartridge 32 is moved from the separated state to the contact state (S16). The optical sensor 182 continuously detects during the movement of the developing cartridge 32 to determine the presence or absence of toner (S17: YES).

  When it is determined that there is no toner (S17: NO), the detection of the optical sensor 182 is terminated (S18), and at the same time, the count of the timer built in the CPU 183 is terminated (S19). The CPU 183 calculates the remaining amount of toner in the toner storage chamber 92 as a percentage from the count value of the timer, that is, the passage time of the detection light in the toner storage chamber 92 (S20), and a level signal corresponding to that percentage. Is input to the empty level gauge lamp 189. The empty level gauge lamp 189 displays the level of the remaining amount of toner in the toner storage chamber 92 corresponding to the level signal from the CPU 183 (S21).

Thereafter, after executing the print job (S22), the cam 120 is rotated by driving the motor 138 to move the developing cartridge 32 from the contact state to the separated state (S23), and the processing is ended.

  According to the toner remaining amount display program, the optical sensor 182 moves with respect to each detection window 100 along the moving path of the developing cartridge 32 while the developing cartridge 32 moves from the separated state to the contact state. The detection light is continuously incident on the detection light passing point to continuously detect the presence or absence of the toner. Therefore, the level of the remaining amount of toner in the toner storage chamber 92 can be displayed as a percentage, so that more accurate detection of the remaining amount of toner can be achieved.

  In the color laser printer 1, as described above, the pickup roller 22 in the paper feeding unit 4 picks up the paper 3 toward the front side and the paper toward the back side at each image forming position. 3 in the direction opposite to the conveyance direction 3 and the conveyance direction of the sheet 3 toward the back side at each image forming position, and the sheet 3 toward the front side of the sheet discharge roller 173 in the sheet discharge unit 6. The paper discharge direction is opposite to the paper discharge direction. Therefore, it is possible to reduce the size of the apparatus while securing the conveyance path for the sheet 3.

  In the color laser printer 1, in each process storage unit 12, the drum cartridge 31 and the development cartridge 32 are arranged in the normal direction and the vertical direction (the thickness direction of the paper 3) with respect to the drum storage unit 13 and the development storage unit 14. It attaches and detaches along the direction which inclines with respect to, ie, the direction which inclines to the back side from the upper part to the lower part. Therefore, the operability of attaching / detaching the drum cartridge 31 and the developing cartridge 32 can be improved.

  In the color laser printer 1, a plurality of sets of drum cartridges 31 and developing cartridges 32 and a plurality of scanner units 30 corresponding thereto are alternately arranged in the normal direction. Therefore, the apparatus can be reduced in size by these efficient arrangements.

  In the above embodiment, the detection window 100 is formed in an approximately elliptical shape in a side view that is long in the vertical direction in a state in which the developing cartridge 32 is mounted in the developing container 14, but for example, a side view that is long in the vertical direction You may form in a substantially rectangular shape.

  In the above embodiment, the presence or absence of toner is determined based on the passage or shielding of the detection light with respect to each detection window 100. For example, when the agitator 69 is rotating, it is based on the light passage time. Thus, the presence or absence of toner can be determined. That is, when the agitator 69 is rotating, the toner agitated by the agitator 69 periodically closes the detection windows 100 in synchronization with the rotation of the agitator 69, so that the detection light is periodically blocked. The passage time of the detection light is intermittently limited. If a threshold value is provided for the passage time of the detection light, the presence or absence of toner can be determined based on the threshold value.

  In the reference example and the embodiment described above, the remaining toner amount is notified by the empty lamp 187, the near empty lamp 188, or the empty level gauge lamp 189 in the toner remaining amount display unit 186. The method of notifying the amount is not limited to this, and for example, informing the host computer for operating the color laser printer 1 by inputting a signal regarding the remaining amount of toner, or by sound (buzzer or the like). Notification can also be made.

In the above embodiment, the remaining amount of toner is detected by one optical sensor 182 for the developing cartridge 32 that moves between the contact state and the separation state. However, a plurality of optical sensors 182 may be provided. For example, a plurality of optical sensors 182 may be provided at intervals in the vertical direction so as to face each detection window 100 without moving the developing cartridge 32. However, it is cheaper to detect the remaining amount of toner with one optical sensor 182 as in the above-described embodiment than to provide a plurality of optical sensors 182.

  In the above-described embodiment, the drum cartridge 31 and the developing cartridge 32 are configured as separate bodies, but may be configured integrally.

  In the above embodiment, the remaining amount of toner is detected by the CPU 183 in conjunction with the contact / separation operation of the developing roller 67 with respect to the photosensitive drum 42 in the developing cartridge 32. However, in order to detect the remaining amount of toner separately. The developing cartridge 32 can also be controlled to move. However, it is possible to simplify the control by detecting the remaining amount of toner in conjunction with the contact / separation operation of the developing cartridge 32.

  In the above embodiment, the optical sensor 182 is fixed to the main casing 2. However, for example, the optical sensor 182 can be moved without moving the developing cartridge 32. However, the configuration can be simplified by moving the developing cartridge 32 as in the above-described embodiment, rather than by moving the optical sensor 182.

  Further, in the above description, the tandem type color laser printer 1 that directly transfers from each photosensitive drum 42 to the paper 3 is exemplified, but the present invention is not limited to this, and for example, toner for each color. An image can be configured as an intermediate transfer type color laser printer in which an image is temporarily transferred from each photosensitive member to an intermediate transfer member and then transferred to a sheet at once, and further, can be configured as a monochrome laser printer.

DESCRIPTION OF SYMBOLS 1 Color laser printer 2 Main body casing 3 Paper 22 Pickup roller 30 Scanner unit 31 Drum cartridge 32 Developing cartridge 42 Photosensitive drum 67 Developing roller 84 Outlet 92 Toner storage chamber 100 Detection window 106 Contacting / separating mechanism 180 Light emitting part 181 Light receiving part 182 Optical sensor 183 CPU
186 Remaining toner 173 Paper discharge roller

Claims (12)

A developer accommodating portion for accommodating the developer therein in order to supply the developer to the photoreceptor on which the electrostatic latent image is formed ;
Provided in the developer accommodating portion, and the detection light transmitting is allowed detection window for detecting the amount of the developer,
An optical sensor having one light receiving unit that receives the detection light emitted from the light emitting unit with respect to one light emitting unit that emits the detection light to the detection window;
Determination means for determining the amount of developer based on the light reception result of the light receiving unit,
The developer accommodating portion has a vertical direction as a component between the first position and the second position so that the detection light passes through different positions in the vertical direction within the same detection window. And it is movable along the direction in which the recording medium is conveyed at the image forming position where an image is formed with respect to the photosensitive member and the direction inclined with respect to the thickness direction of the recording medium perpendicular thereto .
The determination means determines the amount of developer based on each light reception result received by the light receiving portion of the detection light that has passed through the detection window at the first position and the second position, respectively. An image forming apparatus.   The determination means is based on the first position and the second position, the detection light reception result corresponding to the first position, and the detection light reception result corresponding to the second position. The image forming apparatus according to claim 1, wherein an amount of the developer is determined.   The image forming apparatus according to claim 1, further comprising a notification unit configured to notify a developer amount based on a determination result of the determination unit.   4. The image forming apparatus according to claim 1, wherein the first position and the second position are at both ends of a maximum movement range of the developer accommodating portion. 5. A developer cartridge having a developer carrying member carrying the developer, and the developer container;
A photoreceptor on which an electrostatic latent image is formed;
The image forming apparatus according to claim 1, wherein the developer carrying member is disposed above the photoconductor. Contact and separation means for moving the developer cartridge so that the developer carrier contacts and separates from the photoreceptor;
The image forming apparatus according to claim 5, wherein the developer accommodating portion moves between the first position and the second position by the movement of the developing cartridge by the contact / separation unit. . The first position is a state in which the developer carrier and the photoconductor are in contact with each other, and the second position is a state in which the developer carrier and the photoconductor are separated from each other,
In the light receiving section, at the timing when the developer accommodating portion moves from the second position to the first position due to the movement of the developer accommodating portion accompanying the movement of the developer cartridge by the contact / separation means, The image forming apparatus according to claim 6, wherein the image forming apparatus receives detection light, and the determination unit determines the amount of developer based on the light reception result. Comprising a photoreceptor cartridge comprising the photoreceptor,
6. The photoconductor cartridge and the developer cartridge are provided in a plurality of sets corresponding to a plurality of colors, with the photoconductor cartridge and the developer cartridge as a set. The image forming apparatus according to claim 7.   The image forming apparatus according to claim 8, wherein the photoconductors are arranged side by side in a horizontal direction. A supply means for picking up and supplying the recording medium; and a discharging means for discharging the recording medium,
A plurality of sets of the photosensitive cartridge and the developing cartridge are disposed between the supply unit and the discharge unit in a recording medium conveyance path,
The pickup direction of the recording medium picked up by the supply means and the conveyance direction of the recording medium at the image forming position where images are sequentially formed by a plurality of sets of the photosensitive cartridge and the developing cartridge are opposite directions,
10. The recording medium according to claim 8, wherein the recording medium conveyance direction at the image forming position and the discharge direction of the recording medium discharged by the discharge unit are opposite to each other. The image forming apparatus described in 1. The photosensitive member cartridge and the developer cartridge, with respect to the thickness direction of the recording medium conveying direction and Cartesian to the recording medium at the image forming position, characterized in that it is detachably along a direction inclined The image forming apparatus according to claim 10. A plurality of exposure apparatuses are provided corresponding to a plurality of sets of the photosensitive cartridges and the developing cartridges,
11. The plurality of sets of the photosensitive cartridges and the developing cartridges and the exposure apparatuses corresponding thereto are alternately arranged in the recording medium conveyance direction at the image forming position. Item 12. The image forming apparatus according to Item 11.

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