JP2010122516A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus configured such that a plurality of process cartridges are detachably attached to an apparatus body, in which an attaching state of the process cartridge is discriminated in a short time with simple constitution, so as to make discriminating accuracy higher. <P>SOLUTION: The image forming apparatus includes the plurality of process cartridges 2 having at least a photoreceptor drum 21 and a developing unit 2b to be detachably attached to respective image stations, and includes an LED for destaticization 101, and a light emitting element 102 and a light receiving element 103 which are used to detect a residual amount of developer. The LED for destaticization 101 includes an inherent light emitting pattern for each image station. The attaching state of the process cartridge 2 is discriminated based on light received by the light receiving element 103 and the light emitting pattern inherent to the image station. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus including a plurality of process cartridges that can be attached to and detached from an apparatus main body.

  2. Description of the Related Art Conventionally, in an image forming apparatus using an electrophotographic image forming process, an image carrier and a process means acting on the image carrier are integrally formed as a cartridge, and the cartridge can be attached to and detached from the image forming apparatus main body. A cartridge system is adopted.

  According to this process cartridge system, the maintenance of the apparatus main body can be performed by the user himself / herself without depending on the service person, so that the operability of the apparatus main body can be greatly improved.

  There has also been proposed a configuration in which the developing unit is a developing unit, the image carrier, the charging unit, and the cleaning unit are process cartridges, and the developing unit and the process cartridge can be independently attached to and detached from the apparatus main body.

  According to this configuration, maintenance of the apparatus main body can be facilitated, and the apparatus main body can be used in accordance with the lifetime of the main components.

  Here, in an image forming apparatus adopting a conventional process cartridge system, it is possible to determine the mounting state of a process cartridge configured to be detachable from the apparatus main body without providing a special mounting detection sensor or an electric circuit. The following configuration has been proposed.

  For example, when an initialization sequence of an image forming apparatus is executed, a patch image for mounting state determination is formed on an image conveying belt or an intermediate transfer belt, and the patch image is detected by a downstream image detection sensor. A configuration for determining the mounting state of a cartridge is known.

  However, when the mounting state of the process cartridge is determined by forming a patch image, it is necessary to clean the belt surface once before and after forming the patch image, so the wait time until the image forming apparatus becomes ready for printing. Will become longer.

  Further, for example, in Patent Document 1 and Patent Document 2, a motor for driving a rotating body in a detachable process cartridge, a control means for controlling the motor, and a detection means for detecting a load torque of the motor, The structure which provides is disclosed.

  According to this configuration, it is possible to determine the mounting state of the process cartridge by detecting the load torque by the detecting means.

  However, when determining the mounting state of the process cartridge based on the detection result of the load torque, it is necessary to drive the process cartridge in order to determine the mounting state, so that the wait time becomes long.

  Therefore, Patent Document 3 includes a light emitting means for neutralizing the surface potential of the image carrier and a light receiving means for detecting the remaining amount of the developer, and discriminates the mounting state of the process cartridge based on the light receiving state of the light receiving means. The structure provided with the discrimination | determination means to perform is disclosed.

According to this configuration, it is possible to determine the mounting state of the process cartridge with respect to the apparatus main body in a short time without providing a dedicated mounting detection sensor for determining the mounting state of the process cartridge or an electric circuit. .
JP 2003-208060 A JP 2002-72773 A JP 2008-233210 A

  However, the image forming apparatus according to the conventional example has the following problems.

  In the configuration disclosed in Patent Document 3, a station is provided corresponding to a plurality of process cartridges, and in the configuration in which the light emitting unit and the light receiving unit are provided in each station, erroneous determination of the mounting state of the process cartridge is performed. May occur.

  That is, when the process cartridge is mounted in the first station and the process cartridge is not mounted in the adjacent second station, the light from the light emitting means provided in the second station is provided in the first station. There is a risk of interference with the light receiving means.

  In this case, although the process cartridge is mounted on the first station, the determination means for determining the mounting state of the process cartridge is erroneously determined that the process cartridge is not mounted on the first station. I will separate.

  That is, conventionally, in an image forming apparatus in which a plurality of process cartridges are configured to be detachable from the apparatus main body, the mounting state of the process cartridges can be determined in a short time with a simple configuration, and the determination accuracy is higher. The configuration is not disclosed.

  Accordingly, the present invention provides an image forming apparatus in which a plurality of process cartridges are configured to be detachable from the apparatus main body, and can determine the mounting state of the process cartridge in a short time with a simple configuration, and has higher determination accuracy. An object is to provide an image forming apparatus.

In order to achieve the above object, the present invention provides:
An image carrier on which an electrostatic latent image is formed;
Developing means for developing the electrostatic latent image formed on the image carrier with a developer;
A plurality of process cartridges having at least a plurality of process cartridges are detachably attached to an image station provided in the apparatus main body corresponding to each of the process cartridges,
A light-emitting means for discharging the image carrier that irradiates the surface of the image carrier with light to remove the potential of the surface;
A developer remaining amount detecting light emitting means and a developer remaining amount detecting light receiving means; and the light from the developer remaining amount detecting light emitting means is passed through a developer container provided in the developing means. And a developer remaining amount detecting means for detecting the remaining amount of the developer contained in the developer containing portion by receiving the light with the developer remaining amount detecting light receiving means,
Is provided for each of the image stations,
The image forming unit provided with the light receiving means for detecting the remaining amount of developer so as to receive light emitted by the light emitting means for discharging the image carrier when the process cartridge is not mounted on the image station. In the device
The light emitting means for discharging the image carrier is
Each of the image stations has a unique light emission pattern,
Based on the light received by each of the developer remaining amount detecting light receiving means and the light emission pattern unique to the image station provided with the developer remaining amount detecting light receiving means, A determining means for determining the mounting state of the process cartridge is provided.

  According to the present invention, in an image forming apparatus in which a plurality of process cartridges are configured to be detachable from the apparatus main body, the mounting state of the process cartridge can be determined in a short time with a simple configuration, and higher determination accuracy can be achieved. It is possible to provide an image forming apparatus having the same.

  The best mode for carrying out the present invention will be exemplarily described in detail below based on the embodiments with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. Absent.

(Overall configuration of image forming apparatus)
The overall configuration of the image forming apparatus according to the embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic configuration diagram of an image forming apparatus according to the present embodiment. FIG. 3 is a schematic configuration diagram of the image carrier neutralizing light emitting means in the present embodiment.

  In the image forming apparatus according to the present invention, a plurality of process cartridges provided for each developer color (Y: yellow, M: magenta, C: cyan, K: black) can be attached to and detached from the image station of the apparatus main body. The present invention relates to an electrophotographic image forming apparatus.

  Here, the electrophotographic image forming apparatus includes, for example, an electrophotographic copying machine, an electrophotographic printer (for example, an LED printer, a laser beam printer, etc.), an electrophotographic facsimile, and an electrophotographic word processor.

  Further, the process cartridge includes at least a photosensitive drum (image carrier) on which an electrostatic latent image is formed and a developing unit that develops the electrostatic latent image with a developer. Process cartridges are used. In the present embodiment, a process cartridge is used in which a cleaning unit and a charging unit are integrated into a cartridge in addition to the photosensitive drum and the developing unit.

  As shown in FIG. 1, the image forming apparatus has a plurality of image stations for each developer color, and these stations are arranged in the order of yellow station, magenta station, cyan station, and black station from the upper side in FIG. Yes.

  In the present embodiment, the elements provided in the process cartridges of yellow, magenta, cyan, and black are respectively given reference numerals with Y, M, C, and Bk suffixes. However, in the following description, if it is not necessary to distinguish any of the process cartridges, the subscripts may be omitted.

  Reference numeral 21 in FIG. 1 denotes a photosensitive drum as an image carrier. For the surface of the photosensitive drum 21, a charging roller 23 as a charging device, a developing roller 22 for developing an electrostatic latent image formed on the surface of the photosensitive drum 21, and a transfer roller 40 as a transfer device The cleaning blade 28 is disposed in contact therewith.

  The photosensitive drum 21, the charging roller 23, and the cleaning blade 28 are installed in a waste toner storage container 29 and are integrated as a photosensitive drum unit 2a.

  Further, the developing unit 2b (developing means) has a developing container 71 including a developer container 70 as a casing, a developing roller 22, a developer supplying roller 72, a developing blade 73, and a developer conveying member 74 (see FIG. 2).

  The photosensitive drum unit 2a and the developing unit 2b are integrated together and configured as a process cartridge 2 that can be attached to and detached from an image station provided in the apparatus main body.

  Hereinafter, an image forming process of the image forming apparatus having such a configuration will be described.

  The photosensitive drum 21 is rotated at a predetermined speed in the direction of arrow X by a driving device (not shown), a charging bias is applied to the charging roller 23 from a power source (not shown), and the surface of the photosensitive drum 21 is set to a predetermined potential. Charge uniformly (charging process).

  The charged surface of the photosensitive drum 21 is exposed by a laser exposure device (not shown), and an electrostatic latent image is formed on the surface of the photosensitive drum 21.

  The electrostatic latent image formed on the surface of the photosensitive drum 21 is sent to a contact portion with the developing roller 22 and is developed as a developer image by the developer D supplied from the developing roller 22.

  In this embodiment, a non-magnetic one-component toner is used as the developer D. A developing bias is applied between the developing roller 22 and the photosensitive drum 21 by a power source (not shown).

  The developer image developed on the surface of the photosensitive drum 21 is further sent to the contact portion of the transfer roller 40, and the developer image is transferred onto the recording material P conveyed in synchronization. A transfer bias is applied between the transfer roller 40 and the photosensitive drum 21 by a power source (not shown).

  The recording material P to which the developer image has been transferred is sent to the fixing device 50, where the recording material P is heated and pressurized, and the transferred developer image is fixed on the recording material P.

  On the other hand, the developer D remaining on the photosensitive drum 21 without being transferred is scraped off by the cleaning blade 28 and stored in the waste toner storage container 29. The surface of the photosensitive drum 21 from which the remaining developer has been removed is charged again by the charging roller 23, and the above image forming process is repeated.

  Further, the image forming apparatus according to the present embodiment includes a neutralizing LED 101 (FIG. 3) as an image carrier neutralizing light emitting unit that irradiates light on the surface of the photosensitive drum 21 to neutralize the surface potential. Is provided.

  Thus, by providing the neutralizing LED 101 as the neutralizing means on the surface of the photosensitive drum 21, the disturbance of the potential on the photosensitive drum 21 before the charging step can be suppressed, and the deterioration of the image quality can be prevented. become.

  Specifically, before the charging step, the surface of the photosensitive drum 21 is irradiated with the LED light directly from the static elimination LED 101 or via a light guide (not shown) attached to the process cartridge 2, so that the photosensitive drum 21 is irradiated. The residual potential on the surface (surface potential) is removed.

As shown in FIG. 3, the neutralizing LED 101 in the present exemplary embodiment is arranged in the image forming apparatus main body so that the optical axis of the neutralizing LED 101 is parallel to the rotation axis of the photosensitive drum 21.

  The neutralizing LED 101 is on the downstream side of the transfer roller 40 with respect to the rotation direction of the photosensitive drum 21 and on the upstream side of the cleaning blade 28, from the side surface outside the photosensitive area of the photosensitive drum 21 to the surface of the photosensitive drum 21. Irradiate LED light. The state in which the photosensitive drum 21 is irradiated with LED light before the charging process by the neutralizing LED 101 may be referred to as pre-exposure.

(Schematic configuration of development unit)
A schematic configuration of the developing unit 2b in the present embodiment will be described with reference to FIG. FIG. 2 shows a schematic configuration in a cross section of the developing unit 2b in the present embodiment.

  In the developing unit 2b, the developing roller 22 and the developer supply roller 72 are rotatably supported by the developing container 71. The developer supply roller 72 is disposed so as to be in contact with the peripheral surface of the developing roller 22.

  The rotation directions of the developing roller 22 and the developer supply roller 72 are the same direction (reverse direction on the peripheral surface of the contact portion) as indicated by arrows Y and Z in FIG.

  The developing roller 22 is provided with a conductive elastic rubber layer having a predetermined volume resistance around a metal core, and the developer supply roller 72 is provided with a foamed urethane layer around the metal core. Is used. In the surface layer of the foamed urethane layer, foamed cells are opened so that the developer D can be easily held and transported.

  The developing blade 73 is made of an elastic plate such as flexible phosphor bronze, one end of which is fixed to the developing container 71, and the plate surface near the free end is on the surface of the conductive elastic rubber layer of the developing roller 22. It is arranged to rub.

  The developer conveying member 74 is provided inside the developer accommodating portion 70 and is configured to be rotatable about a rotation shaft 76. Further, the front end portion 75 of the developer conveying member 74 is disposed so as to contact the bottom surface of the developer accommodating portion 70.

  Two light transmission parts (incident light transmission window 61 and outgoing light transmission window 62) are provided on the bottom surface of the developer accommodating section 70.

  The front end portion 75 of the developer transport member 74 is configured to contact the light transmission windows 61 and 62 in the developer accommodating portion 70, and the developer D on the light transmission windows 61 and 62 is temporarily received. (In other words, the light transmission windows 61 and 62 are cleaned).

  Next, the movement of the developer in the developing unit 2b being driven will be described.

  When the developing unit 2b is driven, each of the developing roller 22, the developer supplying roller 72, and the developer conveying member 74 rotates in the direction of the arrow in FIG.

  By rotating the developer transport member 74 in the developer container 70, the developer D in the developer container 70 is stirred and transported toward the developer supply roller 72.

The developer D held on the foamed urethane layer of the developer supply roller 72 is sent to a contact portion with the development roller 22 by the rotation of the developer supply roller 72. The developer D reaching the contact portion is rubbed by the surfaces of the developing roller 22 and the developer supply roller 72 moving in opposite directions, and a part of the developer D is transferred and adhered to the surface of the developing roller 22.

  The developer D adhering to the surface of the developing roller 22 is sent to the developing blade 73 as the developing roller 22 rotates. The developing blade 73 regulates the amount of the developer D adhering to the surface of the developing roller 22 to form a uniform thin layer, and frictionally charges the developer D.

  The thinned developer D is sent to the contact portion with the photosensitive drum 21 as the developing roller 22 rotates, and is used to develop the electrostatic latent image formed on the surface of the photosensitive drum 21. .

  The developer D that is not used for development and remains on the surface of the developing roller 22 is conveyed to a contact portion with the developer supplying roller 72 and is removed from the surface of the developing roller 22 by the developer supplying roller 72.

  The removed developer D is sent into the developer container 70 and stirred and mixed with the developer D in the developer container 70.

(About developer remaining amount detection means)
With reference to FIGS. 4 and 5, the developer remaining amount detecting means in the present invention will be described. 4 and 5 are schematic views for explaining a method of detecting the remaining amount of developer in the present embodiment.

  As shown in FIG. 4, the image forming apparatus includes a light emitting element 102 (light emitting means for detecting the remaining amount of developer) that emits LED light and light that has passed through the developer container 70 as the developer remaining amount detecting means. And a light receiving element 103 (light receiving means for detecting the remaining amount of developer). A phototransistor (PTR) is used for the light receiving element 103.

  When there is no developer D in the developer accommodating portion 70, the light emitted from the light emitting element 102 enters from the light transmitting window 61, passes through the toner accommodating portion 70 and exits from the light transmitting window 62, and the light receiving element 103. Led to.

  On the other hand, when the developer D is sufficiently stored in the developer storage unit 70, light is blocked by the developer D on the optical path between the light transmission window 61 and the light transmission window 62, and the light is received. It is configured not to reach the element 103.

  In the present embodiment, since the developer conveying member 74 rotates at a predetermined cycle when the developer remaining amount is detected, the light receiving period and the light shielding period are alternated even when there is no developer D in the developer accommodating portion 70. Appear.

  Here, FIG. 5A shows that when the developer D remains in the developer accommodating portion 70 to some extent, the light is blocked by the developer D conveyed by the tip 75 of the developer conveying member 74. It shows the state.

  FIG. 5B shows a state where the developer D is transported and the remaining amount of the developer becomes small, and the light emitted from the light emitting element 102 is guided to the light receiving element 103.

  When the developer D remains in the developer accommodating portion 70 to some extent, the developer D conveyed by the tip 75 of the developer conveying member 74 is present, so that the light shielding period is longer than when the developer D is not present. (See FIGS. 5A and 5B). That is, the light shielding period corresponds to the amount of the developer D inside the developer container 70.

  Therefore, the remaining amount of the developer D inside the developer accommodating portion 70 can be detected by measuring the ratio of the light-shielding period of the period in which the developer transport member 74 rotates once (hereinafter referred to as a stirring period). .

  The light emitting element 102 can be arranged at an arbitrary position of the image forming apparatus main body by the shape of the light transmitting windows 61 and 62 or the installation of the optical waveguide. In the present embodiment, the light emitting element 102 is disposed at a position facing the neutralizing LED 101 as shown in FIG.

  On the other hand, the arrangement of the light receiving elements 103 will be described below.

  In the state where the process cartridges 2Y and 2M are mounted on the image station as shown in FIG. 3, the light emitted from the neutralizing LEDs 101Y and 101M is blocked by the process cartridges 2Y and 2M. Therefore, light does not reach the light receiving elements 103Y and 103M.

  On the other hand, when the process cartridges 2C and 2Bk are not attached to the image station, the light emitted from the neutralizing LEDs 101C and 101Bk reaches the light receiving elements 103C and 103Bk.

  That is, the light receiving element 103 is provided so that the light receiving element 103 can receive the light emitted from the neutralizing LED 101 only when the process cartridge 2 is not attached to the main body of the image forming apparatus.

  In the present embodiment, the light receiving element 103 is disposed in the vicinity of the optical axis of the neutralizing LED 101, whereby the luminous flux of the LED light emitted from the neutralizing LED 101 can surely reach the light receiving element 103.

(Regarding the discriminating means for discriminating the mounting state of the process cartridge)
With reference to FIGS. 6 and 7, a determination unit for determining the mounting state of the process cartridge 2 in the present embodiment will be described.

  In the present embodiment, a control CPU (not shown) is provided in the apparatus main body as a discriminating means for discriminating the mounting state.

  FIG. 6 is a flowchart showing the determination process of the control CPU in the present embodiment.

  FIG. 7 shows a light emission pattern of light emitted from the static elimination LED 101 in the present embodiment.

  First, when the main body power of the image forming apparatus main body is turned on and the open / close door of the apparatus main body provided for attaching / detaching the process cartridge 2 is closed, an open / closed state detection switch for detecting the open / closed state of the open / close door is provided. The closing of the open / close door is detected (step 1).

  The image forming apparatus turns off the light emitting element 102 (LED) as the developer remaining amount detecting means, and turns on the electricity removing LED 101 with a unique light emission pattern for each image station (step 2).

The light emission pattern unique to each image station at this time is a light emission pattern as shown in FIG. 6. In this embodiment, the light emission patterns have different light emission ON / OFF intervals.

  With the static elimination LED 101 in step 2 turned on, the light pattern received by the light receiving element 103 provided for each image station is monitored (step 3).

  If the light pattern received by the light receiving element 103 does not match the light emission pattern unique to the image station, it is determined that the process cartridge 2 is attached to the image station (step 4).

  Even when light is not received by the light receiving element 103, it is determined that the received light pattern does not match the unique light emission pattern, and it is determined that the process cartridge 2 is mounted on the image station.

  In step 3, if the light pattern received by the light receiving element 103 matches the light emission pattern unique to the image station, it is determined that the process cartridge 2 is not attached to the image station (step 4).

  As described above, the control CPU according to the present embodiment is based on whether the pattern of the light received by the light receiving element 103 matches the light emission pattern unique to the image station in which the light receiving element 103 is provided. Then, the mounting state of the process cartridge is determined.

  Here, the effect of using a light emission pattern unique to each image station as shown in FIG. 6 in determining the mounting state of the process cartridge will be described.

  In general, the input to the light receiving element for detecting the developer remaining amount is processed on the binarization circuit and is often input to the control CPU as a voltage signal of “Hi” or “Low”.

  However, when inputting the neutralizing LED light optimal for neutralizing the residual potential on the surface of the photosensitive drum to the light receiving element, “ON” and “OFF” of lighting of the neutralizing LED is a binarization circuit of the light receiving element. In some cases, it cannot be detected as a “Hi” or “Low” voltage signal processed above.

  In this case, when detecting the mounting state of the process cartridge, it is necessary to lower the threshold value when the light receiving element for detecting the developer remaining amount detects the input voltage signal as “Hi”.

  However, if the threshold value detected as “Hi” is lowered, the detection accuracy of “Hi” decreases due to the influence of noise or the like. That is, the accuracy in determining the mounting state of the process cartridge is lowered.

  Therefore, when the light emitted from the static elimination LED is patterned as a unique light emission pattern, the mounting state may be determined depending on whether the “Hi” pattern detected by the light receiving element matches the unique light emission pattern. Therefore, it becomes possible to maintain the discrimination accuracy.

  However, when a process cartridge is attached to only one image station among a plurality of image stations and a process cartridge is not attached to an adjacent image station, there is a problem in that a light emission pattern of the adjacent image station is recognized and erroneous determination occurs. .

  Therefore, each image station is provided with a unique light emission pattern, and a determination is made based on whether the light receiving element for detecting the remaining amount of developer receives a light emission pattern unique to each image station. It was possible to prevent.

  As described above, in this embodiment, the light receiving element 102 for detecting the remaining amount of developer and the light removal LED 101 for neutralizing the photosensitive drum surface residual potential are diverted so that the light pattern received by the light receiving element 102 is received. Based on the above, it is possible to determine the mounting state of the process cartridge.

  Therefore, it is possible to determine the mounting state of the process cartridge with respect to the apparatus main body with a simple configuration without providing a specialized sensor for detecting the mounting state of the process cartridge such as a photo interrupter or an electric circuit. Therefore, cost reduction of the image forming apparatus main body can be achieved.

  Further, according to the present embodiment, it is necessary to drive the motor for driving the rotating body in the process cartridge and to form the patch image for mounting state determination after the main body power is turned on or the open / close door is closed. Absent.

  Therefore, a long wait time is not required, and the time required to determine the process cartridge mounting state in the initial operation of the image forming apparatus main body can be shortened.

  In the present embodiment, the light receiving element 103 is disposed in the vicinity of the optical axis of the neutralizing LED 101 so that the light flux of the LED light emitted from the neutralizing LED 101 reliably reaches the light receiving element 103.

  However, if such an arrangement is not possible due to space limitations of the apparatus main body, a mirror member, for example, is arranged as the light guide member in the image forming apparatus main body or the process cartridge, and the light receiving element 103 is provided at an arbitrary position. LED light flux may be guided.

  In the present embodiment, the optical path from the light emitted from the static elimination LED 101 to the light receiving element 103 is configured to be blocked by the process cartridge body when the process cartridge is mounted on the image station. ing.

  However, by providing a member that moves on the optical path along with the mounting operation for mounting the process cartridge on the image station, the optical path may be blocked by this member only when the process cartridge is mounted. Good.

  Further, in the present embodiment, the input from the light receiving element 103 to the control CPU is performed by a digital signal binarized by an electric circuit or a microcomputer. That is, the control CPU detects the amount of light received (detected) by the light receiving element 103 as a binarized digital signal.

  Further, according to the present embodiment, it is not necessary to drive a rotating body (photosensitive drum or the like) in the process cartridge in order to determine the mounting state of the process cartridge. Can be suppressed.

  In the present embodiment, the mounting state of the process cartridge is determined using the light emission pattern as shown in FIG. 6 as the light emission pattern of the neutralizing LED 101 unique to the image station.

  However, the light emission pattern unique to the image station is not limited to the light emission pattern shown in FIG.

  For example, a case where a light emission pattern having a different light emission timing for each image station may be used.

  Further, it may be a case where light having a different wavelength is emitted for each image station. Furthermore, the light emission interval, the light emission timing, and the wavelength difference may be combined to form a light emission pattern unique to each image station.

  As described above, in an image forming apparatus in which a plurality of process cartridges are configured to be detachable from the apparatus main body, it is possible to determine the mounting state of the process cartridge in a short time with a simple configuration, and image formation with higher discrimination accuracy An apparatus can be provided.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. 1 is a schematic configuration diagram of a developing unit in an embodiment of the present invention. 1 is a schematic configuration diagram of a light emitting means for image carrier neutralization in an embodiment of the present invention. FIG. FIG. 3 is a schematic diagram for explaining a method for detecting a developer remaining amount in the present embodiment. Schematic for demonstrating the method to detect the developer residual amount in this Embodiment. The flowchart which shows the discrimination process of control CPU in this Embodiment. The light emission pattern of the light emitted from LED for static elimination in this Embodiment.

Explanation of symbols

2 Process Cartridge 2a Photosensitive Drum Unit 2b Developing Unit 21 Photosensitive Drum 22 Developing Roller 61 Incident Light Transmitting Window 62 Emitted Light Transmitting Window 70 Developer Storage Portion 74 Developer Conveying Member 101 Discharge LED
102 light emitting element (light emitting means for detecting developer remaining amount)
103 light receiving element (light receiving means for detecting remaining amount of developer)

Claims (4)

An image carrier on which an electrostatic latent image is formed;
Developing means for developing the electrostatic latent image formed on the image carrier with a developer;
A plurality of process cartridges having at least a plurality of process cartridges are detachably provided to an image station provided in the apparatus main body corresponding to each of the process cartridges,
A light-emitting means for discharging the image carrier that irradiates the surface of the image carrier with light to remove the potential of the surface;
A developer remaining amount detecting light emitting means and a developer remaining amount detecting light receiving means; and the light from the developer remaining amount detecting light emitting means is passed through a developer container provided in the developing means. And a developer remaining amount detecting means for detecting the remaining amount of the developer contained in the developer containing portion by receiving the light with the developer remaining amount detecting light receiving means,
Is provided for each of the image stations,
The image forming unit provided with the light receiving means for detecting the remaining amount of developer so as to receive light emitted by the light emitting means for discharging the image carrier when the process cartridge is not mounted on the image station. In the device
The light emitting means for discharging the image carrier is
Each of the image stations has a unique light emission pattern,
Based on the light received by each of the developer remaining amount detecting light receiving means and the light emission pattern unique to the image station provided with the developer remaining amount detecting light receiving means, An image forming apparatus comprising: a determination unit configured to determine a mounting state of a process cartridge. Each of the image carrier charge eliminating light emitting means,
The image forming apparatus according to claim 1, wherein the light emitting patterns have different light emission intervals. Each of the image carrier charge eliminating light emitting means,
The image forming apparatus according to claim 1, wherein the light emitting patterns have different light emission timings. Each of the image carrier charge eliminating light emitting means,
The image forming apparatus according to claim 1, wherein the image forming apparatus emits light having different wavelengths.

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