JP2007047295A - Developer and developing device and image forming apparatus using them - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simple, inexpensive and accurate developer residual amount confirming mechanism by using a light transmitting mechanism. <P>SOLUTION: By arranging a light guide having shape branched like a branch inside a developing container and on the outside appearance part of the developing container, transmitting light from the outside to one direction part of the light guide and transferring the light between the branched parts of the light guide, a developer area lying between the branched parts of the light guide is irradiated with the light and the various densities of the transmitted light are visually confirmed as the residual amount of the developer from the outside of the developing container. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a process cartridge used in a copying machine, a printer, or the like that employs an electrophotographic system, and an image forming apparatus using the process cartridge.

  Here, the electrophotographic image forming apparatus forms an image on a recording medium using an electrophotographic image forming system. Examples of the electrophotographic image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (for example, a laser beam printer, an LED printer, etc.), a facsimile apparatus, a word processor, and the like.

  The process cartridge is a cartridge in which a charging unit, a developing unit or a cleaning unit and an electrophotographic photosensitive drum are integrally formed, and the cartridge can be attached to and detached from the main body of the electrophotographic image forming apparatus. In addition, at least one of the charging unit, the developing unit, and the cleaning unit and the electrophotographic photosensitive drum are integrally formed into a cartridge that can be attached to and detached from the main body of the electrophotographic image forming apparatus. Further, it means that at least the developing means and the electrophotographic photosensitive drum are integrated into a cartridge so that it can be attached to and detached from the main body of the electrophotographic image forming apparatus.

  Conventionally, in an electrophotographic image forming apparatus (hereinafter referred to as “image forming apparatus”) such as a copying machine, a printer, and a facsimile, an electrostatic latent image formed on an electrophotographic photosensitive member (hereinafter referred to as “photosensitive body”). Is visualized as a developer image (toner image) by developing with a developer (toner) filled in the process cartridge.

  Further, in an image forming apparatus that employs a process cartridge, the user can perform maintenance of the apparatus himself, so that operability can be significantly improved.

  As one of the techniques for improving the convenience of the user who handles the process cartridge, various toner remaining amount detecting means for informing the user of the remaining amount of toner filled in the toner container included in the process cartridge have been devised. Yes. Among such means, there is means for detecting the remaining amount of toner in the toner container by measuring the transmission time of light passing through the toner container within a certain period of time.

  Such a light transmission type toner remaining amount detecting means (hereinafter referred to as “remaining amount detecting means”) is provided in, for example, a light emitting portion and a light receiving portion disposed on the main body side of the image forming apparatus, and a toner container. A light transmission window; and a light guide for guiding detection light emitted from the light emitting unit from the light emitting unit to the light transmitting window and from the light transmitting window to the light receiving unit.

  According to the above configuration, the time during which the detection light can pass through the toner container depends on the remaining amount of toner, and the time becomes shorter if the remaining amount of toner is large, and becomes longer if the remaining amount of toner is small. Then, the remaining amount of toner in the toner container can be estimated by measuring the passage time of the detection light (see, for example, Patent Document 1).

However, recent image forming apparatuses are required to improve convenience.
In particular, in a color image forming apparatus having a plurality of process cartridges, it is a greater challenge to improve the convenience of the process cartridges in a small, easy and inexpensive manner.

For this reason, in order to improve convenience with a small and easy-to-cheap configuration, an attempt to provide a configuration for more accurately grasping the remaining amount of toner makes the configuration more complicated and expensive, resulting in a smaller size. There was a drawback that the purpose of being inexpensive was not fully exhibited. Therefore, in this case, a configuration is proposed in which the remaining amount detection as an improvement in convenience can be realized accurately, compactly, easily and inexpensively.
JP-A-10-186822

  If a configuration for more accurately grasping the remaining amount of developer is provided, there is a drawback that the configuration becomes more complicated and expensive, and the objectives of miniaturization and low cost are not fully exhibited. Therefore, in this case, it was decided to adopt a configuration in which the remaining amount of developer can be visually confirmed with low cost, small size, easy and accurate.

  The conventional visual confirmation mechanism has a problem that the developer adheres to the surface of the transparent member and becomes cloudy, and it is difficult to confirm the remaining amount of the developer from the outside of the developer container.

  In order to solve the problem, by irradiating light from within the developer container to the part where the transparent member for visual confirmation is arranged on the outer wall surface of the developer container, the remaining amount of developer can be confirmed in the shadow, A configuration that achieves the objective is proposed.

  The present invention is a cartridge and an image forming apparatus characterized by the following configurations. The numbers corresponding to the claims are attached as follows.

(1)
In order to achieve the above object, a developing member for developing a latent image formed on the electrophotographic photosensitive member that is detachable from the electrophotographic image forming apparatus main body according to the present invention;
In a developer container having a frame that stores a developer used for development by the developing member, and a light transmissive portion that transmits light in the developer container frame,
An irradiation member for irradiating light from the inside of the developer accommodating portion frame toward the transparent window portion is provided inside the developer accommodating container with a region where the developer is interposed between the light transmitting portion.

  With this configuration, the developing device is configured such that the remaining amount of developer in the developer container can be confirmed by a shadow at the transparent window portion.

(2)
The irradiation member has a light incident portion and a first member formed of an irradiation portion that transmits and further irradiates the incident light;
The second member consisting of the irradiating part that receives the light emitted from the first member and irradiates it again is formed integrally with a light transmissive transparent member, ensuring the positional accuracy of the irradiating part and the light receiving part, and transmitting performance is improved. The developing device according to (1), which can be managed and guaranteed, and further improves assembly and can be inexpensive.

(3)
The transparent window is
Consists of a member integrated with the irradiation member composed of a light incident part, a light guide part and an irradiation part,
The developing device according to (3), which ensures the positional accuracy of the light incident part, the light guide part, and the irradiation part, manages and guarantees the transmission performance, further improves the assemblability, and is inexpensive.

(4)
(3) The developing device according to (4), wherein the light incident portion of the irradiation member is disposed outside the developer accommodating portion frame.

(5)
An image carrier for carrying an electrostatic latent image;
Any one of the developing devices (1) to (4);
Having a light source part irradiated to the light transmission part,
The light transmitting portion of the developing device is configured to be visible.
An electrophotographic image forming apparatus.

It is detachable from the electrophotographic image forming apparatus,
A developing member for developing the latent image formed on the electrophotographic photosensitive member;
A developer storage container having a frame for storing the developer used for development by the developing member, and a light transmitting portion capable of transmitting light for confirming the remaining amount of the developer in the developer storage frame;
In image forming apparatuses and developing apparatuses using these,
The effects described below can be obtained by using the configuration described in the means for solving the problems.

1. Improved evaluation of developing device life, less affected by environment, developer properties, and developer container shape. 2. Optimizing the replacement timing by improving the accuracy of developing device life. Realization of improved accuracy of judgment of developing device life at low cost with easy configuration

(First embodiment)
Embodiments of a multicolor image forming apparatus according to the present invention will be described below in detail with reference to the drawings.

[Overall configuration of multicolor image forming apparatus]
First, the overall configuration of the multicolor image forming apparatus will be outlined with reference to FIG. FIG. 1 is a longitudinal sectional view showing the overall configuration of a full-color laser beam printer 100 which is an aspect of a multicolor image forming apparatus.

  The multicolor image forming apparatus 100 shown in the figure includes four photosensitive drums 1a, 1b, 1c, and 1d arranged in parallel in the vertical direction. The photosensitive drum 1 is driven to rotate counterclockwise in the drawing by a driving means (not shown). A charging device 2 (2a, 2b, 2c, 2d) for uniformly charging the surface of the photosensitive drum 1 in order according to the rotation direction, and a laser beam is irradiated around the photosensitive drum 1 based on image information. A scanner unit 3 (3a, 3b, 3c, 3d) for forming an electrostatic latent image on the drum 1, and a developing device 4 (4a, 4b, 4c, 4d) for developing the toner image by attaching toner to the electrostatic latent image ), An electrostatic transfer device 5 that transfers the toner image on the photosensitive drum 1 to the transfer material S, and a cleaning device 6 (6a, 6b, 6c, which removes transfer residual toner remaining on the surface of the photosensitive drum 1 after transfer). 6d) and the like are provided.

  Here, the photosensitive drum 1, the charging device 2, the developing device 4, and the cleaning device 6 are integrated into a cartridge to form a process cartridge 7.

  Hereinafter, the photosensitive drum 1 will be described in detail.

  The photosensitive drum 1 is configured by providing a photosensitive layer on the outer peripheral surface of an aluminum cylinder having a diameter of 24 mm, for example. The photosensitive drum 1 is rotatably supported at both ends by a support member, and is driven to rotate counterclockwise by transmitting a driving force from a drive motor (not shown) to one end. The

  As the charging device 2, a contact charging type can be used. The charging member is a conductive roller formed in a roller shape. The roller is brought into contact with the surface of the photosensitive drum 1 and the surface of the photosensitive drum 1 is made uniform by applying a charging bias voltage to the roller. To be charged. In this embodiment, since a reversal development system is used, the surface of the photosensitive drum 1 is charged with a negative polarity.

  The scanner unit 3 irradiates the polygon mirror 9 (9a, 9b, 9c, 9d) with image light corresponding to the image signal by a laser diode (not shown) that is rotated at a high speed by a scanner motor (not shown). The image light reflected by the polygon mirror 9 selectively exposes the surface of the charged photosensitive drum 1 through the imaging lens 10 (10a, 10b, 10c, 10d) to form an electrostatic latent image. It is composed.

  The developing device 4 includes toner containers 41 (41 a, 41 b, 41 c, 41 d) that respectively store yellow, magenta, cyan, and black toners. The toner in the developing container unit 46 is supplied by the feeding mechanism 42. Feed to roller 43.

  The toner supply roller 43 rotates in the clockwise direction in the drawing, and supplies toner to the developing sleeve 40 and peels off the toner from the developing sleeve 40 after developing to the photosensitive drum 1.

The toner supplied to the developing sleeve 40 is applied to the outer periphery of the developing sleeve 40 that rotates in the clockwise direction in the figure by a developing blade 44 that is pressed against the outer periphery of the developing sleeve 40, and is given an electric charge.

  Then, a developing bias is applied to the developing sleeve 40 facing the photosensitive drum 1 on which the latent image is formed, whereby toner development is performed on the photosensitive drum 1 in accordance with the latent image.

  The electrostatic transfer device 5 is provided with an electrostatic conveyance belt 11 that circulates and moves so as to face and contact all the photosensitive drums 1a, 1b, 1c, and 1d. The electrostatic transport belt 11 is made of a resin film or a multilayer film member having a resin layer provided on a rubber base layer. The electrostatic conveyance belt 11 is stretched around a driving roller 13, driven rollers 14a and 14b, and a tension roller 15. The transfer material S is electrostatically adsorbed on the outer peripheral surface on the left side in the drawing and is attached to the photosensitive drum 1. The transfer material S is circulated so as to contact it. As a result, the transfer material S is conveyed to the transfer position by the electrostatic transfer belt 11, and the toner image on the photosensitive drum 1 is transferred.

  The transfer roller 12 (12a, 12b, 12c, 12d) is arranged in parallel at a position in contact with the inside of the electrostatic transfer belt 11 and facing the four photosensitive drums 1a, 1b, 1c, 1d. A positive polarity bias is applied to the transfer rollers 12 during transfer, and positive polarity charges are applied to the transfer material S via the electrostatic transfer belt 11. The negative polarity toner image on the photosensitive drum 1 is transferred to the transfer material S in contact with the photosensitive drum 1 by the electric field generated at this time.

  The paper feed unit 16 feeds and conveys the transfer material S to the image forming unit, and a plurality of transfer materials S are stored in the paper feed cassette 17. At the time of image formation, the paper feed roller 18 (half-moon roller) and the registration roller 19 are driven and rotated in accordance with the image forming operation to separate and feed the transfer material S in the paper feed cassette 17 one by one. After abutting against the registration roller 19 and temporarily forming a loop, the rotation of the electrostatic transfer belt 11 and the image writing position are synchronized, and the sheet is fed to the electrostatic transfer belt 11 by the registration roller 19.

  The fixing unit 20 fixes a plurality of color toner images transferred to the transfer material S, and includes a heating roller 21a that rotates, and a pressure roller 21b that presses and applies heat and pressure to the transfer material S. Consists of.

  That is, the transfer material S to which the toner image on the photosensitive drum 1 is transferred is conveyed by the pressure roller 21b when passing through the fixing unit 20, and is given heat and pressure by the heating roller 21a. As a result, the toner images of a plurality of colors are fixed on the surface of the transfer material S.

  As an image forming operation, the process cartridges 7a, 7b, 7c, and 7d are sequentially driven in accordance with the print timing, and the photosensitive drums 1a, 1b, 1c, and 1d are rotated counterclockwise in accordance with the drive. Driven. Then, the scanner units 3 corresponding to the respective process cartridges 7 are sequentially driven. By this driving, the charging roller 2 imparts a uniform charge to the circumferential surface of the photosensitive drum 1, and the scanner unit 3 exposes the circumferential surface of the photosensitive drum 1 according to the image signal to perform photosensitive drum 1. An electrostatic latent image is formed on the peripheral surface. The developing sleeve 40 in the developing device 4 forms (develops) a toner image on the circumferential surface of the photosensitive drum 1 by transferring the toner to the low potential portion of the electrostatic latent image.

  At the timing when the leading edge of the toner image on the circumferential surface of the most upstream photosensitive drum is rotated and conveyed to a point facing the electrostatic transfer belt 11, the printing start position of the transfer material S coincides with that point. The registration roller 19 starts rotating and feeds the transfer material S to the electrostatic transfer belt 11.

  The transfer material S is pressed against the outer periphery of the electrostatic transfer belt 11 so as to be sandwiched between the electrostatic adsorption roller 22 and the electrostatic transfer belt 11, and a voltage is applied between the electrostatic transfer belt 11 and the electrostatic adsorption roller 22. By applying the charge, charge is induced in the transfer material S that is a dielectric and the dielectric layer of the electrostatic transfer belt 11, and the transfer material is electrostatically attracted to the outer periphery of the electrostatic transfer belt 11. As a result, the transfer material S is stably adsorbed to the electrostatic transfer belt 11 and conveyed to the most downstream transfer unit.

  While being conveyed in this way, the toner image on each photoconductive drum 1 is sequentially transferred to the transfer material S by an electric field formed between each photoconductive drum 1 and the transfer roller 12.

  The transfer material S on which the toner images of four colors are transferred is separated from the electrostatic transfer belt 11 by the curvature of the belt driving roller 13 and is carried into the fixing unit 20. After the toner image is thermally fixed by the fixing unit 20, the transfer material S is discharged by the paper discharge roller 23 from the paper discharge unit 24 to the outside of the main body with the image surface facing down.

[Configuration of process cartridge]
Next, the process cartridge embodying the present invention will be described in detail with reference to FIGS. 2 and 3 show a main cross section and a perspective view of the process cartridge 7 containing toner. The yellow, magenta, cyan, and black process cartridges 7a, 7b, 7c, and 7d have the same configuration.

  The process cartridge 7 includes an electrophotographic photosensitive drum 1 (hereinafter referred to as a photosensitive drum 1) that is an image carrier, a cleaner unit 50 that includes a charging unit and a cleaning unit, and an electrostatic latent image on the photosensitive drum 1. It is divided into a developing unit 4 having developing means for developing.

  In the cleaner unit 50, the photosensitive drum 1 is rotatably attached to the cleaning frame 51 via bearing members 31 (31a, 31b). On the periphery of the photosensitive drum 1, primary charging means 2 for uniformly charging the photosensitive layer provided on the outer peripheral surface of the photosensitive drum 1, and developer (residual toner) remaining on the photosensitive drum 1 after transfer A cleaning blade 60 and a flexible sheet member 80 are disposed. Further, residual toner (waste toner) removed from the surface of the photosensitive drum 1 by the cleaning blade 60 is stored in a waste toner chamber 55 provided behind the cleaning frame. The transfer residual toner on the drum passes through the drum contact portion of the flexible sheet member 80 and reaches the position of the cleaning blade 60. The residual toner removed from the drum by the cleaning blade 60 is removed from the cleaning frame. The contact condition of the flexible sheet member 80 is set so as not to leak out of the body 51.

  The developing unit 4 includes a photosensitive sleeve 1 and a developing sleeve 40 that rotates in the arrow Y direction while maintaining a small gap, and developing frame bodies 45a and 45b that store toner.

  The developing frame bodies 45a and 45b are coupled (coupled by ultrasonic welding or the like) to form the developing container unit 46.

  The developing sleeve 40 is rotatably supported by a developing container unit 46 via a bearing member, and a toner supply roller 43 and a developing blade which are in contact with the developing sleeve 40 and rotate in the arrow Z direction on the circumference of the developing sleeve 40. 44 are arranged respectively. Further, a toner transport mechanism 42 for stirring the toner contained in the developer container unit 46 and transporting the toner to the toner supply roller 43 is provided.

  In the developing unit 4, the coupling holes 47 and 48 provided at both ends of the developing container unit 46 are aligned with the support holes 52 and 53 provided at both ends of the cleaning frame 51 of the cleaner unit 50, and the pins 49 are inserted from both ends of the cleaner unit 50. As a result, the entire developing unit 4 has a suspended structure that is swingably supported with respect to the cleaner unit 50.

  Further, the developing unit 4 is always urged by the pressure spring 54 so that the developing sleeve 40 contacts the photosensitive drum 1 around the support holes 52 and 53. At the time of development, the toner stored in the toner container 41 is conveyed to the toner supply roller 43 by the toner stirring mechanism 42. A toner supply roller 43 that rotates in the arrow Y direction supplies the toner to the developing sleeve 40 by rubbing against the developing sleeve 40 that rotates in the arrow Z direction, and carries the toner on the developing sleeve 40. The toner carried on the developing sleeve 40 reaches the developing blade 44 as the developing sleeve 40 rotates, and the developing blade 44 regulates the toner to form a predetermined toner thin layer, and a desired charged charge amount. Is granted. The toner thinned on the developing sleeve 40 is transported to the developing portion where the photosensitive drum 1 and the developing sleeve 40 approach each other as the developing sleeve 40 rotates, and is applied to the developing sleeve 40 from a power source (not shown) in the developing portion. The developed bias adheres to the electrostatic latent image formed on the surface of the photosensitive drum 1 and develops the latent image. The toner remaining on the surface of the developing sleeve 40 without contributing to the development of the electrostatic latent image is returned to the developing device with the rotation of the developing sleeve 40, and the developing sleeve is rubbed with the toner supply roller 43. 40 is peeled off and collected. The collected toner is stirred and mixed with the remaining toner by the toner stirring mechanism 42.

[Light transmission type developer remaining amount confirmation means]
Next, the light transmission type developer remaining amount checking means will be described with reference to FIGS.

  FIG. 4 is a cross-sectional view of the process cartridge 7 provided with the light transmission type developer remaining amount confirmation unit according to the present embodiment, and FIG. 5 illustrates the light transmission type developer remaining amount confirmation unit according to the present embodiment. It is a cross-sectional perspective view of the development unit 4 provided.

  The light guide 81 is disposed in the developer container 45 at a position where it does not interfere with the toner feeding mechanism 42, and light is incident from the external light source 25, so that the light can be visually observed on the outer wall (see FIG. 8) of the developer container 45. The remaining developer amount can be confirmed by the remaining developer amount confirmation unit 89 which is a part of the arranged light guide 81.

  The details of the light transmission type developer confirmation means will be described with reference to the detailed view of the light guide 81 in FIG. 6. The light irradiated from the external light source 25 (shown in FIG. 4) to the first light guide light receiving unit 81a 6 passes through the light transmission path 88 and passes through the light transmission refracting portion 82a (see the enlarged view of FIG. 6) having a shape that allows the light transmission angle to be changed. The amount of the developer entering the space E region by entering the second light receiving portion 83a from the guide irradiation portion 82b through the space E and passing through the developer remaining amount confirmation portion 89 is determined as the developer amount. The remaining amount confirmation unit 89 can confirm the density of transmitted light due to the shadow of the developer.

  The light guide 81 includes a first light guide portion 82 having a first irradiation portion 82b, a second light receiving portion 83a, and a second light guide portion 83 composed of a developer remaining amount confirmation portion 89 in a branch shape. It is composed of one piece.

  At that time, in the space E area, the first light guide is used to prevent the developer from lumping up in the space E area so that the powder level of the developer changes as the developer is consumed. An arrangement in which a clearance is secured is performed between the portion 82 and the second light guide portion 83.

  FIG. 7 shows how the developer remaining amount changes in the developer remaining amount checking unit 89 according to the density of the transmitted light (shaded portion: developer remaining amount 89a) due to the shadow of the developer.

  FIG. 9 is a side external view of the process cartridge 7. The developer remaining amount confirmation portion 89 shown here is disposed at a position that can be confirmed from the outside of the process cartridge 7 or the developer container 45, and as shown in FIG. The developer remaining amount confirmation unit 89 can be confirmed from the outside of the electrophotographic image forming apparatus 100.

  In the above-described configuration, the developer residual light that is integrally formed with the light guide 81 disposed inside the developer container 45 using light irradiated from the outside of the process cartridge 7 and is disposed so as to be confirmed from the outside of the developer container 45. The remaining amount of developer 89h in the developer container 45 can be visually confirmed from the outside of the electrophotographic image forming apparatus 7 by the density of the transmitted light of the amount confirmation unit 89.

1 is a cross-sectional view showing an example of a multicolor image forming apparatus according to the present invention. Sectional drawing which shows the process cartridge which concerns on this invention. The perspective view which shows the process cartridge which concerns on this invention. FIG. 3 is a cross-sectional view showing a process cartridge including a light transmission type developer remaining amount checking unit according to the present invention. FIG. 3 is a cross-sectional perspective view showing a developing unit including a light transmission type developer remaining amount checking unit according to the present invention. FIG. 2 is a perspective view showing a light transmission type developer remaining amount checking unit according to the present invention. FIG. 3 is a detailed view showing a light transmission type developer remaining amount checking unit according to the present invention. FIG. 3 is an external view showing a process cartridge including a light transmission type developer remaining amount confirmation unit according to the present invention. FIG. 3 is an external view showing a multicolor image forming apparatus including a light transmission type developer remaining amount checking unit according to the present invention.

Explanation of symbols

1 (1a, 1b, 1c, 1d) Photosensitive drum 2 (2a, 2b, 2c, 2d) Charging device 3 (3a, 3b, 3c, 3d) Scanner unit 4 (4a, 4b, 4c, 4d) Developing device, development Unit 5 Electrostatic transfer means 6 (6a, 6b, 6c, 6d) Cleaning device 7 (7a, 7b, 7c, 7d) Process cartridge 9 Polygon mirror 10 Imaging lens 11 Electrostatic transfer belt 12 Transfer roller 13 Drive roller 14a, 14b Follower roller 15 Tension roller 16 Paper feed unit 17 Paper feed cassette 18 Paper feed roller 19 Registration roller 20 Fixing unit 21a Heating roller 21b Pressure roller 22 Electrostatic adsorption roller 23 Paper discharge roller 24 Paper discharge unit 25 External light source 31 Bearing member 40 (40a, 40b, 40c, 40d) Developing sleeve 42 Toner feeding mechanism 42a Toner feeding member Shaft 42b Toner feeding member 43 Toner supply roller 44 Developing blade 45 Developer container 45a, 45b Developing frame 46 Developer container unit 47, 48 Joint hole 49 Pin,
DESCRIPTION OF SYMBOLS 50 Cleaner unit 51 Cleaning frame body 52,53 Support hole 54 Pressure spring 55 Waste toner chamber 60 Cleaning blade 80 Flexible sheet member 81 Light guide 81a First light guide light-receiving part 82 First light guide part 82a Light transmission Refraction unit 82b First light guide irradiation unit 83 Second light guide unit 83a Second light receiving unit 88 Light transmission path 89 Developer remaining amount confirmation unit 89h Developer remaining amount 100 Image forming apparatus main body 101 Front door
E space

Claims (5)

It is detachable from the electrophotographic image forming apparatus,
A developing member for developing the latent image formed on the electrophotographic photosensitive member;
In a developer container having a frame body that stores a developer used for development by the developing member, and a light transmission part that transmits light into the developer container frame,
An irradiation member for irradiating light from the inside of the developer accommodating portion frame toward the light transmitting portion is provided inside the developer containing container by providing a region where the developer is interposed between the light transmitting portion,
A developing device. The irradiation member has a light incident portion and a first member formed of an irradiation portion that transmits and further irradiates the incident light;
The developing device according to claim 1, wherein the second member including the irradiation unit that receives the light irradiated from the first member and irradiates the light again is integrally formed of a light transmitting transparent member. The transparent window is
The developing device according to claim 2, comprising a light incident portion, a transmission portion, and an irradiation portion, and integrally formed with the light transmission transparent member.   The developing device according to claim 2, wherein the light incident portion of the irradiation member is disposed outside the developer accommodating portion frame. An electrophotographic photoreceptor;
A developing device according to any one of claims 1, 2, 3, or 4,
Having a light source part irradiated to the light transmission part,
The transparent window of the developing device is configured to be visible.
An electrophotographic image forming apparatus.

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