JP2003295596A - Developer detection method, developing device, process cartridge and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of realizing stable notification on the residual amount of toner even in constitution where a signal for detecting the residual amount of the toner easily gets unstable by a shock given when a developing roller abuts on a photoreceptor drum when forming an image. <P>SOLUTION: The light emitting element 30a and the light receiving element 30b of a developing device constituted to rock with a supporting shaft 49 as the center of turning so that an image carrier 1 can contact with/separate from the developing roller 40 start to detect the developer after a stirring member 42 is rotated by an amount equal to or above the deflection of a stirring blade 42x. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process cartridge used in a copying machine or a printer adopting an electrophotographic method, and an image forming apparatus using the process cartridge.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus using an electrophotographic image forming process, an image carrier and process means acting on the image carrier are integrally formed into a cartridge so that the image carrier can be attached to and detached from the main body of the image forming apparatus. The process cartridge system is adopted. According to this process cartridge system, the maintenance of the device can be performed by the user himself without resorting to a serviceman, and the operability can be markedly improved. Therefore, this process cartridge system has been widely adopted in image forming apparatuses.

As a developing means of a process cartridge used in an image forming apparatus, generally, a contact developing system in which a developing roller is in contact with an image bearing member for developing, and a developing roller with respect to the image bearing member are used. There are known two configurations of a non-contact developing system in which development is performed with a predetermined gap provided. In any of the methods, the developing roller and the image carrier are in a state of being urged against the image carrier in order to maintain a predetermined contact pressure, an amount of intrusion, or a gap during image formation. There is a need.

However, in the contact developing type process cartridge for developing while the developing roller is in contact with the image carrier, the developing roller is biased by the image carrier, that is, the elastic layer of the developing roller is Since it is in contact with the image carrier at a predetermined contact pressure, the elastic layer of the developing roller is permanently deformed when it is not used for a long period of time when it is mounted in the image forming apparatus. Image unevenness may occur.

Further, when the bias is not applied to the developing roller when the developing roller is not in operation, the toner on the developing roller may adhere to the image bearing member and stain the recording medium.

As a structure for avoiding the above problem, an image forming apparatus having a structure provided with a mechanism for separating the image bearing member and the developing roller when the image forming operation is not performed has been conventionally proposed. ing.

Further, even in such a cartridge, there is a cartridge in which when the toner is used up, the user is notified of the replacement time of the cartridge to improve the convenience.

[0008]

However, in the conventional image forming apparatus as described above, the signal for detecting the remaining toner amount is likely to be unstable due to a shock when the developing roller and the photosensitive drum come into contact with each other during image formation. There was a problem.

Therefore, according to the present invention, even when the signal for detecting the remaining toner amount is likely to become unstable due to the shock when the developing roller and the photosensitive drum contact each other during image formation, the stable remaining toner amount is notified. An object of the present invention is to provide an image forming apparatus capable of performing the above.

[0010]

In order to solve the above-mentioned problems, a method for detecting a developer according to the present invention includes a developing roller which is a developer carrying member, a developing frame member which holds the developing roller, and a developer. A developer container to be housed, a flexible member that is bent by abutting against the inner wall of the developer container to bend, and a stirring member that rotates to stir the developer in the developer container; An input gear for rotating the image forming apparatus, and a developer detecting unit for detecting the remaining amount of the developer in the developer container. A developing device is configured so that a drive gear provided on the apparatus main body side is meshed with each other, and is configured to be swingable around a support shaft so that the image carrier and the developing roller can be brought into contact with and separated from each other. The developer remaining amount detecting means of the Characterized in that to start the developer detection after above rotation.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] An embodiment of a multicolor image forming apparatus as an electrophotographic image forming apparatus according to the present invention will be described in detail below with reference to the drawings.

{Overall Configuration of Multicolor Image Forming Apparatus and Electrophotographic Image Forming Process} First, the overall configuration of the image forming apparatus and electrophotographic image formation will be outlined with reference to FIGS. 1 and 2. FIG. 1 is a vertical cross-sectional view showing the overall configuration of a full-color laser beam printer 100 which is one mode of a multicolor image forming apparatus.

The image forming apparatus 100 shown in FIG. 1 includes four photosensitive drums 1a to 1a which are image carriers arranged in a vertical direction.
It is equipped with 1d. The photosensitive drum 1 is rotationally driven counterclockwise in the figure by a driving unit (not shown).

On the periphery of the photosensitive drum 1, charging devices 2a to 2d for uniformly charging the surface of the photosensitive drum 1 in order according to the rotation direction thereof, and irradiating a laser beam on the photosensitive drum 1 based on image information. Scanner units 3a to 3d for forming electrostatic latent images, and a developing unit 4a for developing a toner image by attaching toner as a developer to the electrostatic latent images.
4d, an electrostatic transfer device 5 that transfers the toner image on the photosensitive drum 1 to the transfer material S, and a cleaning device 6a that 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 unit 4, and the cleaning device 6 are integrated into a cartridge to form a process cartridge 7.

The photosensitive drum 1 is constituted by coating an organic photoconductive layer (OPC photosensitive member) on the outer peripheral surface of an aluminum cylinder having a diameter of 30 mm, for example. Photoconductor drum 1
Has both ends rotatably supported by support members, and is driven to rotate counterclockwise by transmitting a driving force from a drive motor (not shown) to one end.

As the charging device 2, a contact charging type device can be used. The charging member is a conductive roller formed in the shape of a roller. The roller is brought into contact with the surface of the photosensitive drum 1 and a charging bias voltage is applied to the roller to make the surface of the photosensitive drum 1 uniform. It is to be charged.

The scanner unit 3 is arranged substantially in the horizontal direction of the photosensitive drum 1 and has a laser diode (not shown).
The image light corresponding to the image signal is rotated at a high speed by a scanner motor (not shown) by the polygon mirror 9
(9a, 9b, 9c, 9d) is irradiated. The image light reflected by the polygon mirror 9 is formed by the imaging lens 10 (10a, 10a).
b, 10c, 10d), the surface of the charged photosensitive drum 1 is selectively exposed to form an electrostatic latent image.

Each of the developing devices 4a, 4b, 4c, 4d is composed of a developing device in which toner of each color of yellow, magenta, cyan and black is stored.

All the photosensitive drums 1a, 1b, 1c,
An electrostatic transfer belt 11 is disposed so as to face 1d and to circulate so as to come into contact therewith. The electrostatic transfer belt 11 is 10 ¹¹ to 10 ¹⁴
It is composed of a film-like member having a volume specific resistance of Ω · cm and a thickness of about 150 μm. This electrostatic transfer belt 11
Is supported by rollers 13, 14a, 14b, 15 on four axes in the vertical direction, and electrostatically adsorbs a transfer material S as a recording medium on the outer peripheral surface on the left side in the figure to transfer the transfer material S to the photosensitive drum 1. Circulate to make contact. As a result, the transfer material S is conveyed to the transfer position by the electrostatic transfer belt 11, and the photosensitive drum 1
The toner image on the top is transferred.

The inner surface of the electrostatic transfer belt 11 is abutted and
Transfer rollers 5 (5a, 5b, 5c, 5d) are arranged in parallel at positions facing the respective photosensitive drums 1a, 1b, 1c, 1d. A positive charge is applied from the transfer roller 5 to the transfer material S via the electrostatic transfer belt 11, and an electric field generated by the charge causes a negative polarity on the photosensitive drum 1 on a sheet in contact with the photosensitive drum 1. Toner image is transferred.

The electrostatic transfer belt 11 is a belt having a peripheral length of about 700 mm and a thickness of 150 μm, and is stretched around four rollers of a driving roller 13, driven rollers 14a and 14b, and a tension roller 15 and rotated in the direction of the arrow in the figure. To do. As a result, the toner image is transferred while the electrostatic transfer belt 11 described above circulates and the transfer material S is conveyed from the driven roller 14a side to the drive roller 13 side.

The feeding unit 16 feeds and conveys the transfer material S to the image forming unit, and a plurality of transfer materials S are fed to the feeding cassette.
It is stored in 17. At the time of image formation, the feeding roller 18 (half-moon roller) and the registration roller pair 19 are driven and rotated in accordance with the image forming operation to separate and feed the transfer materials S in the feeding cassette 17 one by one, and at the end of the transfer material S. Is a pair of registration rollers
After hitting 19 and once stopping, forming a loop, the rotation of the electrostatic transfer belt 11 and the cycle of the image writing position are taken,
The registration roller pair 19 feeds the electrostatic transfer belt 11.

The fixing section 20 is for fixing the toner images of a plurality of colors transferred to the transfer material S, and includes a rotating heating roller 21a and a pressurizing member which is in pressure contact with the heating roller 21a to apply heat and pressure to the transfer material S. A fixing roller pair 21 including a roller 21b is provided.

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

In the image forming operation, the process cartridges 7a, 7b, 7c and 7d are driven in accordance with the recording timing, and the photosensitive drum 1a,
1b, 1c, and 1d are rotationally driven. Then, the scanner unit 3 corresponding to each process cartridge 7
Are sequentially driven. By this drive, the charging rollers 2a ...
2d applies a uniform charge to the peripheral surface of the photosensitive drum 1, and the scanner unit 3 exposes the peripheral surface of the photosensitive drum 1 according to an image signal to electrostatically charge the peripheral surface of the photosensitive drum 1. Form a latent image. The developing roller in the developing device 4 transfers the toner to the low potential portion of the electrostatic latent image to form (develop) a toner image on the peripheral surface of the photosensitive drum 1.

At the timing when the leading edge of the toner image on the peripheral surface of the most upstream photosensitive drum 1 is rotatably conveyed to the opposite point to the electrostatic transfer belt 11, the recording start position of the transfer material S is set at the opposite point. The pair of registration rollers 19 starts to rotate so that the transfer material S is fed to the electrostatic transfer belt 11 so as to coincide with each other.

The transfer material S is sandwiched between the electrostatic attraction roller 22 and the electrostatic transfer belt 11 so that the electrostatic transfer belt 11 is held.
Of the dielectric material of the transfer material S as a dielectric and the dielectric layer of the electrostatic transfer belt 11 by applying a voltage between the electrostatic transfer belt 11 and the electrostatic attraction roller 22 while being pressed against the outer periphery of the electrostatic transfer belt 11. The transfer material is configured to be electrostatically attracted to the outer circumference of the electrostatic transfer belt 11. As a result, the transfer material S is stably attracted to the electrostatic transfer belt 11 and is conveyed to the most downstream transfer unit.

While being conveyed in this way, the transfer material S sequentially transfers the toner images on the respective photosensitive drums 1 by the electric field formed between the respective photosensitive drums 1 and the transfer roller 5. The transfer material S onto which the toner images of four colors have been 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. The transfer material S is heat-fixed with the toner image by the fixing unit 20, and is then discharged from the discharge unit 24 to the outside of the main body by the discharge roller pair 23 with the image surface facing down.

{Process Cartridge} Next, the process cartridge will be described in detail with reference to FIGS. 2 is a main cross section of the process cartridge 7 containing toner, FIG. 3 is an assembly perspective view, and FIG. 4 is a drive transmission mechanism. The yellow, magenta, cyan, and black process cartridges 7a to 7d have the same configuration.

As shown in FIG. 2, the process cartridge 7 includes a drum-shaped image carrier as an image carrier, that is, a photosensitive drum 1, an image carrier unit 50 having a charging unit and a cleaning unit, and a photosensitive member. It has a developing unit 4 having developing means for developing the electrostatic latent image on the drum 1.

In the image carrier unit 50, the photosensitive drum 1 is rotatably attached to the cleaning frame 51 via bearings 31a and 31b (bearings). On the circumference of the photosensitive drum 1, a charging device 2 for uniformly charging the surface of the photosensitive drum 1 and a cleaning blade 60 for removing the developer (toner) remaining on the photosensitive drum 1. Is arranged, and the driving force of a driving motor (not shown) is transmitted to one end on the rear side in the drawing, so that the photosensitive drum 1 is rotationally driven counterclockwise in the drawing in accordance with an image forming operation.

As shown in FIG. 3, the developing unit 4 has a support shaft 49, which is a swing center provided on each of bearing members 47 and 48 attached to both ends of the developing unit 4, as a center.
The developing unit 4 as a whole is swingably supported by the pin 49a with respect to the image carrier unit 50, and in the state where the process cartridge 7 alone (not attached to the printer body), the support shaft 49 is centered. Further, the developing unit 4 is constantly biased by the biasing spring 54 which is a biasing member so that the developing roller 40 contacts the photosensitive drum 1 by the rotation moment. Further, the toner container 41 of the developing unit 4 is integrally provided with an acting portion 46 for contacting a separating means (described later) of the apparatus main body 100 when the developing roller 40 is separated from the photosensitive drum 1. Here support shaft 49
Is disposed between the developing roller 40 and the rear end portion of the toner container 41, and by pushing up the acting portion 46,
40 is in a state of being separated from the photosensitive drum 1 by a predetermined gap.

As shown in FIG. 2, the developing unit 4 comprises a developing roller 40 that contacts the photosensitive drum 1 and rotates in the direction of arrow Y, a toner container 41 containing toner and a developing frame 45. To be done. The developing roller 40 is rotatably supported by a developing frame body 45 via a bearing member, and on the circumference of the developing roller 40, a toner supply roller 43 and a developing blade 44 which come into contact with the developing roller 40 and rotate in the arrow Z direction. Are arranged respectively. Further, the toner container 41 is provided with a stirring member 42 that stirs the stored toner and also transports the toner to the toner supply roller 43.

During development, when the toner stored by the stirring member 42 that conveys toner is conveyed to the toner supply roller 43, the toner supply roller 43 that rotates in the arrow Y direction rotates the toner in the arrow Z direction. It is supplied to the developing roller 40 by rubbing against the developing roller 40 and is carried on the developing roller 40. The toner carried on the developing roller 40 reaches the developing blade 44 with the rotation of the developing roller 40, and the developing blade 44 regulates the toner to give a desired charge amount, and a predetermined toner thin layer. To form.
The regulated toner is conveyed to the developing unit where the photosensitive drum 1 and the developing roller 40 are in contact with each other as the developing roller 40 rotates, and in the developing unit, the developing roller is supplied from a power source (not shown).
By the DC developing bias applied to 40, the photosensitive drum 1
The latent image is developed by adhering to the electrostatic latent image formed on the surface of the.

In the contact developing system in which the photosensitive drum 1 and the developing roller 40 are brought into contact with each other to develop as in this embodiment, the photosensitive drum 1 is a rigid body and the developing roller 40 is a roller having an elastic body. Is preferred. As the elastic body, a solid rubber single layer or a solid rubber layer coated with a resin in consideration of charge imparting property to toner is used.

The developing unit 4 sends out the toner by a rotatable stirring member 42 which is a toner feeding means in the toner container 41, and scrapes off the toner which has not contributed to the development by the toner supply roller 43 which is driven to rotate. Always supply fresh toner to the developing roller 40. Then, while the developing roller 40 is rotated, a toner layer to which a triboelectric charge has been applied by the developing blade 44 is formed on the surface of the developing roller 40, and the toner is transferred to the photosensitive drum 1 according to the latent image to thereby transfer the toner. An image is formed and visualized.

The stirring member 42 is a flexible P having a thickness of 0.1 mm.
42x stirring blade, which is a flexible member made of ET sheet
(Sheet) is provided on the outer circumference of rotation. The agitating blade 42x bends and rubs against the toner container to convey the toner to the developing roller 40 side while agitating the toner without excess.

Here, the bending amount of the stirring member 42 means a virtual point w which comes into contact with the toner container when the stirring blade 42x attached to the stirring member 42 is in an unloaded state and the tip y of the actual stirring blade 42x.
Is the angle from the center of stirring, and in this embodiment is 30 degrees,
It is bent.

Here, the stirring blade 42x is bent by 30 degrees in order to stabilize the behavior of the toner in the toner container and increase the accuracy of detection of the remaining amount of toner.

[Drive transmission mechanism] The drive transmission of the developing device is performed by mounting the process cartridge on the main body of the image forming apparatus so that the drive gear on the main body side meshes with the input gear on the process cartridge side.

FIG. 4 is a view showing that the drive gear 77 and the input gear 78 are meshingly transmitting and rotating.

The drive gear 77 on the main body side is rotated by a motor (not shown) to transmit the drive force to the developing device.

The input gear 78 rotates the idler gear 79 in the direction of the arrow. The idler gear 79 rotates the front stirring gear 76 and the developing side idler gear 90.

The stirring gear 76 rotates the stirring member 42a to stir the toner to the developing roller side.

Further, the stirring idler gear 81 is rotated in the direction of the arrow.

The stirring idler gear 81 rotates the stirring gear 82 in the direction of the arrow, and the stirring gear 82 rotates the rear stirring member 42b to stir and convey the toner in the toner container to the developing roller 40 side.

The developing side idler gear 90 is a developing roller gear 91.
The coating roller gear 92 is rotated in the direction of the arrow to develop the latent image written on the photosensitive drum 1. Bias spring here
The support shaft 49 serves as the center of rotation, and the developing roller 40 and the photosensitive drum 1 are in contact with each other.

{Toner Remaining Amount Detecting Method} Next, a light transmitting toner remaining amount detecting method will be described with reference to FIGS. 2 and 5 to 8.

Inside the toner container 41, a first stirring member 42a and a second stirring member 42b are provided in order from the side closer to the developing roller 40. By rotating the respective stirring members 42a, 42b, the toner The toner T is conveyed to the supply roller 43. The first stirring member 42a also has a wiping function of removing the toner T attached to the light guide portions 245a and 246a, in addition to carrying the toner T.

Further, as shown in FIGS. 5 and 6, on the side surface of the toner container 41 of the image forming apparatus main body, a light emitting element 30a such as an infrared LED which is a light emitting member and a phototransistor which is a light receiving member are provided. The light receiving element 30b is arranged. In FIG. 2 and FIG. 6, the detection light L emitted from the light emitting element 30a is refracted outside the toner container 41, and a part of the detection light L passes through a light guide portion 245a arranged over the length of the toner container 41. The light is emitted into the toner container 41 toward the light guide portion 246a. Then, the detection light L emitted into the toner container 41
Are incident on the light guide portion 246a and are refracted, and the toner container 41
A part of the detection light L that has passed to the outside reaches the light receiving element 30b via the light guide portion 246a that is also provided over the length of the toner container 41, and the light receiving element 30b is there while the stirring member 1 is rotating. The remaining amount of the toner T stored in the toner container 41 is detected depending on how long the detection light L is received. The light emitting element 30a is vertically below the toner container 41, and the light receiving element 30b is the toner container 41.
Is arranged vertically above.

Here, the ratio of the time when the light receiving element 30b receives light changes depending on the amount of toner T in the toner container 41. Therefore, when the toner T occupies the space in the toner container 41 for a certain amount or more, the toner container 4 is guided through the light guide portion 245a.
The light incident on the inside 1 is blocked by the toner T, and the light guide portion 2
Since the light does not reach 46a, the light receiving element 30b does not receive light. When the toner T in the toner container 41 decreases, the stirring member 42
The ratio of the light passing between the light guide portions 245a and 246a gradually increases due to the stirring of a. By this, the remaining amount of the toner T is known.

With such a configuration, the stirring member 42
It is possible to sequentially detect the remaining amount of the toner T stored in the toner container 41 by changing the length of time that the light receiving element 30b receives the detection light L while a is rotated once. The user is informed that the toner T is running out in the toner container 41.

FIG. 7 is an electrical block diagram of the main body of the image forming apparatus. As shown in FIG. 7, an MPU 1000, which is an engine controller, is installed in the image forming apparatus 100 to perform electrical control. After the power of the main unit is turned on, it is possible to detect various states and perform image forming operations.

The light emitting element 30a is caused to emit light by an input / output signal from the IO port of the MPU, the state of the cartridge is detected by the light receiving element 30b, and the remaining toner amount is displayed on the display 70 of the computer 60 as shown in FIG. As a result, the remaining amount of toner can be successively notified to the user.

{Attachment / Detachment Method of Process Cartridge to / from Image Forming Apparatus Body} Next, an attaching / detaching method of the process cartridge 7 to / from the image forming apparatus body 100 will be described with reference to FIG. As shown in FIG. 9, the process cartridge 7 is attachable to and detachable from the image forming apparatus main body 100. At this time, the process cartridge 7 is horizontal when the front door 32 of the image forming apparatus main body 100 is open. It is configured to be inserted and removed in the direction. The front door 32 is rotated about the shaft 32a with respect to the apparatus main body 30 and is in a closed state as shown in FIG. 1 or in a laterally opened state as shown in FIG.

The front door 32 includes an electrostatic transfer belt 11, a driving roller 13 for supporting the electrostatic transfer belt 11, a driven roller 14a, and a driven roller 14.
b, the tension roller 15, and the transfer rollers 5a and 5
b, 5c and 5d are provided.

(Separation Mechanism of Process Cartridge) Next, the separation mechanism for attaching and detaching the process cartridge 7 to and from the apparatus main body 100 will be described with reference to FIGS. 9 and 10.

As described above, the process cartridge 7
In the single unit state, the developing roller 40 is always in contact with the photosensitive drum 1 as shown in FIG. The process cartridge 7 is attached to the apparatus main body 100 by inserting bearings 31a and 31b for supporting the photosensitive drum 1 from the direction of arrow A along the guide groove 33 as shown in FIGS. .

At this time, as shown in FIG. 1, FIG. 9, and FIG. 10, the developing unit 4 is arranged on the side of the photosensitive drum 1 with the support shaft 49 as the center of rotation on the inner side in the insertion direction of the process cartridge 7 of the apparatus main body 100. A separating plate 80 for separating the developing roller 40 from the photosensitive drum 1 against the biasing spring 54 that biases the developing roller 40 toward the photosensitive drum 1.
Are arranged. Yellow, magenta, and
Separation plate 80a for pushing up the operating portions 46a to 46d provided in the developing units 4a to 4d for cyan and black, respectively.
.About.80d are provided respectively, and are driven by driving means such as a stepping motor (not shown).

The developing unit 4 has a separating position where the separating plate 80 is pushed up to separate the developing roller 40 from the photosensitive drum 1, and a developing position where the separating plate 80 is released to push the developing roller 40 into contact with the photosensitive drum 1. It is possible to move to. Then, only during image formation, the push-up of the spacing plate 80 is released to move the developing unit 4 to the developing position.

In FIG. 10, the process cartridge 7
When is attached to the apparatus main body 100, the spacing plate 80 is in a pushed-up state. Therefore, when the process cartridge 7 is inserted in the direction A, the operating portion 46Y provided on the developing unit 4 rides on the spacing plate 80 and moves to the position 46, so that the developing unit 4 moves to the position 4Y of the two-dot chain line. To the position indicated by the solid line 4 and the developing roller 40 is separated from the photosensitive drum 1 by a predetermined gap PC.

This separated state is always maintained when the power is off and when the development is not performed. Therefore, even when the process cartridge 7 is not used for a long time with the process cartridge 7 mounted, the developing roller 40 is always separated from the photosensitive drum 1, so that the developing roller 40 can be used as the photosensitive drum 1 for a long time. It is possible to reliably prevent the permanent deformation of the roller layer caused by the contact.

{Image forming operation} When the image forming operation is started by the print signal next, as shown in FIG. 11, the push-up of the spacing plate 80 is released at the developing operation timing,
The urging force of the urging spring 54 causes the developing unit 4 to rotate about the support shaft 49, and the developing roller 40 comes into contact with the photosensitive drum 1 to be in a developable state as shown in FIG.

The process cartridge 7 has a suspension structure in which the developing unit 4 is swingably supported with respect to the image carrier unit 50 around the support shaft 49. The roller 40 is biased by a biasing spring 54 in a direction in which the roller 40 contacts the photosensitive drum 1. Therefore, at the time of releasing the separation, that is, at the time of image formation, a stable contact pressure to the photosensitive drum 1 can be obtained only by the spring pressure of the biasing spring 54 without being influenced by the main body configuration or the like.

The direction FE in which the photosensitive drum 1 and the developing roller 40 contact at this time is the same as the rotation direction of the input gear 78. Therefore, with respect to the stopped input gear 78, the stirring idler gear 79 moves in the FG direction around the support shaft 49 as the center of rotation, and rotates around the contact 79P in the direction FH opposite to the normal rotation direction.

Here, the developing unit 4 is the photosensitive drum 1
By swinging in a direction in which the developing roller 40 and the developing roller 40 come into contact with each other,
A force acts on the stirring blade 42x in the direction opposite to the direction in which the stirring blade 42x bends (the direction in which the bending is released), and the stirring member 42 and the stirring blade 42x
Becomes unstable, the behavior of the toner in the toner container 41 is not stable, and it becomes difficult to detect the normal amount of remaining toner.

Further, due to the contact shock between the photosensitive drum 1 and the developing roller 40, the toner in the vicinity of the toner remaining amount detecting portion becomes unstable.

{Developer detecting method of the present invention} In the developer detecting method of the present invention, the developing roller 40 and the photosensitive drum 1 are rotated about the support shaft 49 to come into contact with and separate from each other, and the stirring blade 42x is provided. In the sequence of detecting the remaining amount of toner based on the amount of light transmission during one rotation, the start of the residual toner detection is waited until the stirring blade 42x is sufficiently bent. As a result, the unstable state at the beginning of the stirring rotation due to the backlash of the stirring system caused by the fact that the rotation direction of the input gear 78 that drives the developing unit 4 and the developing contact direction FE are the same is avoided, and the remaining toner amount is detected. It stabilizes and improves reliability.

FIG. 12 is an example of a sequence for realizing the toner remaining amount detection of the present invention. In the present embodiment, the image forming sequence (S
3 to S9), the remaining toner amount detection sequence may be included in the image forming sequence.

The toner remaining amount detection sequence is MPU100.
When it is executed at 0 (S1), infrared light is emitted from the light emitting element 30a (S2). After that, the image forming operation forms an image as described above according to an image forming command from the formatter 134 (see FIG. 7) in a predetermined pattern, a predetermined number of sheets (S3 to S10).

During the image forming operation, the MPU 1000 informs the user of the cartridge life (remaining amount of toner) (S9). However, due to the contact shock between the photosensitive drum 1 and the developing roller 40 (S5), the drive gear 77 Is slightly different from the rotation of the stirring gear 76 via the stirring idler gear 79, and a force is applied to the stirring idler gear 79 in the direction of arrow FH, so that the stirring blade 42x is bent in a slightly different manner from the steady rotation. As a result, the stirring property of the toner becomes unstable,
The reliability of the toner detection signal decreases.

In this embodiment, since the first stirring member 42a starts to rotate, the deflection (30 °) of the stirring blade 42x,
It waits until 42x moves (S6) and detects the toner amount. As a result, the toner residual detection signal is stabilized. .

To convert the remaining amount of toner, the amount of toner consumed (cartridge life) is converted from the light receiving time when the light receiving element 30b detects light (S7) (S8). Then, the converted value is compared with the converted value of the life written in advance in the non-volatile memory 143 of the image processing apparatus main body to notify the user of the cartridge life (S9).

After the image formation is completed (S10), the photosensitive drum 1 and the developing roller 40 are separated by the separating plate 80 (S1).
1) The stirring by the stirring member 42 is stopped (S12), the light emitting element 30a is turned off, and the remaining amount detection sequence is ended.

In this embodiment, the present invention is applied to the electrophotographic image forming apparatus in which the process cartridge is detachably mounted. However, the cartridge developing device, that is, the developing cartridge is detachable. It goes without saying that the present invention can also be applied to a mounted electrophotographic image forming apparatus.

As described above, in the sequence of detecting the remaining amount of toner in the process cartridge 7 in which the developing roller 40 and the photosensitive drum 1 are in contact with each other during image formation, the stirring blade 42x rotates more than the bending amount of the stirring blade 42x. The developer detection was started later. As a result, the unstable state at the beginning of the stirring rotation can be avoided, the remaining toner amount detection can be stabilized, the reliability can be improved, and the convenience for the user can be achieved.

Further, the reliability of the toner detection signal can be improved by limiting the attitude of the developing roller 40 when the toner amount is detected only when the drum and the developing roller are connected to each other.

Further, since the method of detecting the developer is the light transmission type, it is possible to provide the inexpensive developing unit 4.

Further, by providing the light guide portion 245a below the rotation center of the stirring member 42 and the light guide portion 246a above the rotation center of the stirring member 42, it is possible to reliably detect when the toner runs out.

The stirring blade 42x has a thickness of 0.05-0.
By using the PET sheet having a thickness of 2 mm, the cleaning properties of the light guide portions 245a and 246a can be improved.

Further, by having the light emitting element 30a and the light receiving element 30b at positions facing the light guide portions 245a and 246a, the detection light L can be surely transmitted to the inside of the toner container 41.

Further, by detecting the remaining amount of the developer at the time when the light receiving element 30b detects the light, variation in the sensitivity of the light amount-voltage conversion due to the individual difference is suppressed as compared with the detection method by the voltage of the light receiving element 30b. It is possible to eliminate the cost of selection.

Further, the developing unit 4 and the image carrier unit
By integrally forming 50 and the process cartridge 7 as a process cartridge, convenience for the user is improved and the replaceability of the process cartridge 7 for the user is improved.

[0084]

As described above, in the sequence of detecting the remaining amount of toner in the cartridge in which the developing roller and the photosensitive drum are in contact with each other during image formation, after the flexible member rotates more than the bending amount of the flexible member, The developer detection has started.
As a result, the unstable state at the beginning of the stirring rotation can be avoided, the remaining toner amount detection can be stabilized, the reliability can be improved, and the convenience for the user can be achieved.

Further, the reliability of the toner detection signal can be improved by limiting the attitude of the developing roller at the time of detecting the toner amount to the drum-developing roller contact.

Further, since the method of detecting the developer is the light transmission type, an inexpensive developing device can be provided.

By providing the first light transmission window above the rotation center of the stirring member and the second light transmission window below the rotation center of the stirring member, it is possible to reliably detect when the toner is exhausted.

The flexible member has a thickness of 0.05-0.
By using the PET sheet having a thickness of 2 mm, the cleaning property of the light transmitting window can be improved.

Further, by having the light emitting element and the light receiving element at the position facing the light transmitting window, the detection light can be surely transmitted into the developer container.

Further, by detecting the remaining amount of the developer at the time when the light receiving element detects the light, it is possible to suppress the variation in the sensitivity of the light receiving element, and the cost such as selection is not required.

Further, by integrally forming the developing device and the image carrying unit as a process cartridge, the convenience of the user is improved and the exchangability of the user's cartridge is improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a multicolor image forming apparatus according to this embodiment.

FIG. 2 is a sectional view of a process cartridge.

FIG. 3 is an assembled perspective view showing a process cartridge.

FIG. 4 is a diagram showing drive transmission of a process cartridge.

FIG. 5 is a frame perspective view of the image forming apparatus.

FIG. 6 is a perspective view showing an optical path of toner detection light of the process cartridge.

FIG. 7 is an electrical block diagram of the main body of the image forming apparatus.

FIG. 8 is a computer and a display that communicate with the main body of the image forming apparatus.

FIG. 9 is a diagram showing how the process cartridge is attached to the image forming apparatus main body.

FIG. 10 is a diagram showing separation of the photosensitive drum and the developing roller of the process cartridge.

FIG. 11 is a diagram showing contact between the photosensitive drum and the developing roller of the process cartridge.

FIG. 12 is a flowchart of a developer detection method.

[Explanation of symbols]

L ... Detection light S ... Transfer material T ... Toner w ... virtual point y ... tip 1 ... Photosensitive drum 2 ... Charging device 3a to 3d ... Scanner unit 4 ... Development unit 5 ... Electrostatic transfer device 5a to 5d ... Transfer roller 6 ... Cleaning device 7 ... Process cartridge 9 ... Polygon mirror 10… Imaging lens 11… Electrostatic transfer belt 13… Drive roller 14a, 14b ... driven roller 15… Tension roller 16… Feeding department 17… Feed cassette 18… Feeding roller 19… Registration roller pair 20 ... Fixing unit 21… Fixing roller pair 21a ... Heating roller 21b ... Pressure roller 22… Electrostatic attraction roller 23… Ejection roller pair 24… Ejector 30a ... Light emitting element 30b ... Light receiving element 31a, 31b ... Bearing 32… Front door 32a ... axis 33… Guide groove 40 ... Developing roller 41… Toner container 42 ... Stirrer 42a ... First stirring member 42b ... Second stirring member 42x ... stirring blade 43… Toner supply roller 44… Development blade 45 ... Development frame 46… Working part 47, 48 ... Bearing members 49… Support shaft 49a ... pin 50 ... Image carrier unit 51… Cleaning frame 54 ... Pressure spring 60… Cleaning blade 70… Display 76… stirring gear 77… Drive gear 78… Input gear 79… Stir idler gear 79P ... Contact 80 ... Spacer 81… Stirring idler gear 82 ... stirring gear 90… Developer idler gear 91… Developing roller gear 92… Coating roller gear 100 ... Image forming device 134 ... formatter 143 ... Nonvolatile memory 245a, 246a ... Optical guide section

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Naofumi Horikawa             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F-term (reference) 2H077 AB03 AB14 AB18 AD06 AD13                       AD17 BA02 BA07 BA08 BA09                       DA15 DA42 DA64 DA78 DA81                       DA86 DB10 DB14

Claims (11)

[Claims] 1. A developing roller which is a developer carrying member, a developing frame body which holds the developing roller, a developer container which contains a developer, and a contact roller rub against the inner wall of the developer container to bend. A flexible member is provided, a stirring member that rotates to stir the developer in the developer container, an input gear for rotating the stirring member, and a developer detection unit that detects the remaining amount of the developer. By including the input gear in the main body of the image forming apparatus,
A drive gear provided on the image forming apparatus main body side is configured to mesh with each other, and is configured to be swingable around a support shaft so that the image carrier and the developing roller can be brought into and out of contact with each other. The developer detecting method, wherein the developer remaining amount detecting means of the developing device starts the developer detection after the stirring member has rotated more than a bending amount of the flexible member. 2. The developing device has a first attitude in which the image carrier and the developing roller are in contact with each other and a second attitude in which they are separated from each other, and the developer remaining amount detecting means detects the developer. ,
The developer detecting method according to claim 1, wherein the method is performed only in the first posture. 3. A developing roller which is a developer carrying member, a developing frame body which holds the developing roller, a developer container which contains the developer, and a contact roller rub against the inner wall of the developer container to bend. A flexible member is provided, a stirring member that rotates to stir the developer in the developer container, an input gear for rotating the stirring member, and a developer detection unit that detects the remaining amount of the developer. By including the input gear in the main body of the image forming apparatus,
In a developing device configured such that a drive gear provided on the image forming apparatus main body side meshes with each other, the supporting shaft is swingable about a supporting shaft so that an image carrier and a developing roller can be brought into contact with and separated from each other. The developer remaining amount detecting means starts the developer detection after the stirring member rotates by the amount of bending of the flexible member or more. 4. The developing device according to claim 3, wherein the developer detecting unit is a light transmission type. 5. The developing device has a first posture in which the image carrier and the developing roller are in contact with each other and a second posture in which they are separated from each other, and the developer remaining amount detecting means detects the developer. ,
The developing device according to claim 3, wherein the developing device is performed only in the first posture. 6. The developer container includes a first light transmission window disposed above a rotation center of the stirring member and a second light transmission window disposed below a rotation center of the stirring member. The developing device according to claim 3, further comprising: 7. The flexible member has a thickness of 0.05-0.
7. The developing device according to claim 3, wherein the developing device is a PET sheet having a size of 2 mm. 8. The developing device, wherein the developer remaining amount detecting means detects the remaining amount of the developer at the time when the light receiving member receives the light. 9. A process cartridge comprising: the developing device according to claim 1; and an image carrier unit that holds an image carrier. 10. The image forming apparatus according to claim 1, wherein the developing device is attachable / detachable, wherein the developer detecting unit emits light to one of the first light transmitting window and the second light transmitting window. An image forming apparatus comprising a member, and a light receiving member facing the other member. 11. The image forming apparatus to which the process cartridge according to claim 9 is attachable / detachable, wherein the developer detecting means has a light emitting member in one of the first light transmitting window or the second light transmitting window. The image forming apparatus is characterized in that a light receiving member is arranged opposite to the other.