JPH11194602A - Developing device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the total amount of toner with high accuracy by providing a stirring member in a developing device with a shading member equipped with a forcible shading part and setting the width of a detecting forcibl shading time for every developing device by the forcible shading part. SOLUTION: When the toner is the same amount, a black developing unit Db transmits more light than a color developing unit. Therefore, 'no residual toner' is displayed earlier. In order to solve this problem, the threshold of the unit Db must be set different from that of the color developing unit. In such a case, the stirring member 15 of the unit Db is provided with another member 86, and the light is forcibly shaded in the width of the specified time in the forcible shading part 87 by the member 86 when the member 15 advances to rotate to a specified position. Thus, maximum residual detection output pulse width which can be detected in a specified stirring cycle is less than the residual detection output pulse width detected when the residual toner is the same amount in the conventional manner. Namely, the threshold is set to the same set value as the color developing unit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a copying machine or a printer.

[0002]

2. Description of the Related Art An electrophotographic image forming apparatus for forming an image on a transfer material using an electrophotographic method is, for example, an electrophotographic copying machine, an electrophotographic printer (for example, a laser beam printer, an LED printer), a facsimile machine or a word processor. Has been put to practical use.

Here, the configuration of a color laser printer and a developer remaining amount detecting device used in the color laser printer will be described with reference to FIGS.

In FIG. 15, an image forming apparatus main body 101 is shown.
Inside, a rotary developing device 102, a transfer drum 103 as a transfer material carrier, an image carrier 104 composed of an electrophotographic photosensitive drum, and the like are provided.

[0005] The transfer material P fed from a cassette 105 arranged below the main body 101 of the image forming apparatus is wound around a transfer drum 103 and conveyed, and is transferred to an image carrier 104.
The toner image formed on the surface of is transferred to the transfer material P, is permanently fixed by the fixing device 106, and is discharged outside the apparatus.

[0006] The rotary developing device 102 has four color developing units 102M, 102C, 102Y and 102B having four color toners of magenta, cyan, yellow and black. These four color developing units 102M, 102C, 10C
2Y and 102B are arranged rotatably with respect to shaft 102a. A revolving gear is provided on the shaft 102a, and each of the developing devices 102M, 102C, 102Y, and 102B rotates in conjunction with a revolving gear disposed on the outer periphery of the revolving gear. 102
The postures of C, 102Y, and 102B are kept constant.

At the time of image formation, the developing units 102M, 1M
The developing device of the color corresponding to the latent image among the 02C, 102Y, and 102B is stopped at a position facing the image carrier 104, and the developing roller 102b is further opposed to the surface of the image carrier 104 at a small interval. Is positioned. Then, at the time of development, the developing roller 102b receives a bias application and a rotation drive to develop the latent image on the image carrier 104 to form a toner image.

Each of the developing units 102M, 102C, 102Y,
A supply roller 102d is rubbed against a developing roller 102b disposed in the inside of the developing roller 102B, so that a developer that has not contributed to the development is scraped off, and a fresh developer is always supplied.

FIG. 16 shows a conventional developer remaining amount detecting means employing a light transmission system. Light transmitting windows 115a and 115b for detecting the remaining amount of the developer are welded to the welding receiving portions 111a and 111b of the developer container 111 by using a method such as ultrasonic welding. Then, the detection light L emitted from the light emitting unit 106a provided on the image forming apparatus main body 101 side transmits through the light transmitting member 116a, further transmits through the light transmitting member 116b of the light transmitting window 115b, and then enters the image forming apparatus main body. 101
The remaining amount of the developer is detected by receiving light at the light receiving unit 106b provided on the side. At this time, the developer stirring member 107 provided in the developer container 111 rotates to wipe the inner surfaces of the light transmitting members 116a and 116b, and the remaining amount is detected by detecting the detection light L at that time. .

More specifically, as shown in FIG. 17, the detection light L is detected as a pulse width t in the stirring period T, and the pulse width t increases as the amount of the detection light L increases. That is, the pulse width t increases as the remaining amount of the developer in the developer container 111 decreases. Therefore, when the pulse width t reaches a predetermined value, that is, a certain threshold value, the user is notified that "the remaining amount of the developer is small". The threshold was set for each type of developer and stirring speed.

[0011]

However, when a plurality of developing devices are provided as in the above-described conventional rotary developing device, when the stirring speed of each developing device is different depending on the characteristics of the stored developer, A different threshold value must be set for each developing unit, and the processing is complicated.

Accordingly, an object of the present invention is to enable the threshold value of each developing device to be set simply or to the same set value even when the type of developer and the stirring speed of each developing device are different. Another object of the present invention is to provide an image forming apparatus and a developing device having a developer remaining amount detecting mechanism capable of detecting the remaining amount of developer with high accuracy and at the same time.

[0013]

The above object is achieved by an image forming apparatus according to the present invention. In summary, the present invention provides:
A developing container for storing the developer, a stirring member that rotates in the developing container and stirs the developer, and a light-detection-type remaining-amount-detecting unit that detects the remaining amount of the developer in the developing container. In the image forming apparatus having a plurality of developing devices having different colors, the stirring member has a light-shielding member having an integral or separate forced light-shielding portion. An image forming apparatus is characterized in that a detection light forced light shielding time width is set for each apparatus.

The threshold of the output pulse width of the developer remaining amount detecting means for giving a notice of the remaining amount of the developer is set to a predetermined time width by the forcible light-shielding section to forcibly shade each developing device. It is preferable to set the same value. It is preferable that the stirring member has a stirring blade at one end, and the light shielding member is provided on a side opposite to the stirring blade with respect to a stirring rotation center axis of the stirring member. It is preferable that the forced light-shielding time width of the plurality of developing devices differs depending on the type of the developer. According to another aspect, it is preferable that the forced light shielding time width of the plurality of developing devices differs depending on the stirring speed of the stirring member.

It is preferable that the stirring blade provided on the stirring member is a light shielding member having the forced light shielding portion. According to another aspect, it is preferable that a stirring stay holding a stirring blade provided on the stirring member is a light shielding member including the forced light shielding unit.

According to another aspect of the present invention, a plurality of developing devices of different colors including a developing container for storing a developer, and a stirring member in the developing container for stirring the developer, and a light emitting unit And a light detection type developer remaining amount detecting unit including a light receiving unit, and a stirring rotation center of the stirring member is formed near an optical axis of the light emitting unit and the light receiving unit. Image forming apparatus provided with an opening for performing the forced light shielding by providing an angled member near the opening of the stirring member.

It is preferable that a portion having the above angle is formed by bending a portion of the stirring stay provided on the stirring member, which supports the stirring blade, located near the opening.

According to another aspect of the present invention, a plurality of developing devices of different colors including a developing container for storing a developer, and a stirring member in the developing container for stirring the developer, And a light detection type developer remaining amount detecting unit including a light-receiving unit and a light-receiving unit. In the image forming apparatus provided with an opening for the image forming apparatus, an image forming apparatus is provided in which forced light shielding is performed by adjusting the width of the opening.

It is preferable that the width of the opening is adjusted by a member different from the stirring member. According to another aspect, it is preferable that the width of the opening is adjusted by a stirring blade attached to the stirring member. According to still another aspect, it is preferable that the width of the opening is adjusted by a stirring stay attached to the stirring member.

The developing device includes upper and lower window members provided in the developing container so as to allow light to pass therethrough, and the stirring member has stirring blades for cleaning the upper and lower window members. The developer remaining amount detecting means has a light emitting unit and a light receiving unit attached to the apparatus main body near the window member,
Preferably, when the window member is cleaned by the stirring blade, the light receiving unit receives light emitted from the light emitting unit.

According to another aspect of the present invention, there is provided a developing container for storing a developer, and a stirring member in the developing container for stirring the developer. In the developing device used in an image forming apparatus having a light detection type developer remaining amount detecting unit for detecting, the stirring member has a light shielding member having an integral or separate forced light shielding unit. Is provided.

According to another aspect of the present invention, there is provided a developing device for use in an image forming apparatus including a light detecting type developer remaining amount detecting unit including a light emitting unit and a light receiving unit, which stores a developer. A developing container, a stirring member provided in the developing container for stirring the developer, a stirring rotation center of the stirring member provided near the optical axis of the light emitting section and the light receiving section, and provided on the stirring member. In a developing device having an opening for transmitting light, a member having an angle is attached near an opening of the stirring member to form a forced light shielding unit.

According to another aspect of the present invention, there is provided a developing device for use in an image forming apparatus provided with a light detecting type developer remaining amount detecting means including a light emitting portion and a light receiving portion, wherein the developer is stored. A developing container, a stirring member provided in the developing container for stirring the developer, a stirring rotation center of the stirring member provided near the optical axis of the light emitting unit and the light receiving unit, and a stirring member provided in the stirring member. A developing device having an opening for transmitting light, wherein the forcing is performed by adjusting the width of the opening.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a developing device and an image forming apparatus according to the present invention will be described in more detail with reference to the drawings.

Embodiment 1 A first embodiment in which the present invention is applied to a multicolor electrophotographic image forming apparatus will be described with reference to FIGS.

(Image Forming Apparatus) First, a schematic configuration of the image forming apparatus of the present embodiment will be described. FIG. 1 shows a laser beam printer which is an embodiment of an image forming apparatus for forming a color image by an electrophotographic method.

The surface of a drum-shaped electrophotographic photosensitive member (hereinafter referred to as "photosensitive drum") 1 rotating at a constant speed is uniformly charged by charging means 2. Then, the latent image is formed by irradiating the photosensitive drum 1 with a laser beam corresponding to the image information from the exposing means 3, and the latent image is formed into four developing cartridges Dy and D.
Develop with m, Dc and Dk (collectively D). Then, the developed image formed on the photosensitive drum 1 is sequentially transferred onto the belt-like intermediate transfer member 4 so as to be superposed thereon, thereby forming a color image. This color image is transferred by a transfer unit 6 from a recording medium (for example, a recording paper, an OHP sheet, etc.) P conveyed by a conveying unit 5 from a feeding unit. And
The recording medium P is transported to the fixing unit 7 to fix the color image, and is discharged to the discharge unit 8 on the upper surface of the apparatus.

Next, the configuration of each of the above components will be specifically described.

The photosensitive drum 1, as a process cartridge U, has a cleaning means 9 for removing toner remaining on the photosensitive drum 1 after transferring an image of a developer (hereinafter referred to as "toner") to the intermediate transfer member 4. And is integrally formed with the container-shaped frame 9a. The process cartridge U is removably mounted to the image forming apparatus main body 30 and can be replaced by the user according to the life of the photosensitive drum 1.

The photosensitive drum 1 is formed by applying an organic photoconductive layer to the outside of an aluminum cylinder having a diameter of about 50 mm, and is rotatable around a container-like frame 9a of cleaning means 9 which also serves as a holder for the photosensitive drum 1. It is supported by.

Around the photosensitive drum 1, a cleaning blade 9b for scraping and removing the toner remaining on the photosensitive drum 1 and a charging means 2 are provided. Therefore, in this embodiment, the photosensitive drum 1, the cleaning means 9, and the charging means 2 are integrally formed as a cartridge to constitute a process cartridge U which can be attached to and detached from the apparatus main body 30.

The photosensitive drum 1 rotates counterclockwise in FIG. 1 according to an image forming operation by transmitting a driving force of a driving motor (not shown).

The charging means 2 of this embodiment employs a so-called contact charging method, and applies a voltage to a conductive roller which rotates in contact with the surface of the photosensitive drum 1 to apply a voltage to the photosensitive drum 1. This is to charge the surface uniformly.

When an image signal is given to a laser diode (not shown), the exposing means 3 for exposing the charged photosensitive drum 1 irradiates the polygon mirror 3a with image light corresponding to the image signal. The polygon mirror 3a is rotated at a high speed by a scanner motor 3b, and the image light reflected by the mirror 3a selectively exposes the surface of the photosensitive drum 1 rotating at a constant speed via the imaging lens 3c and the reflection mirror 3d. To form an electrostatic latent image.

The electrostatic latent image is developed for each color by a developing cartridge (developing device) D. The configuration of the developing cartridge D will be described later. Developing cartridge D
Is transferred to the intermediate transfer member 4.

A transfer unit (intermediate transfer member) 4 serving as a second image bearing member collectively transfers a plurality of toner images, which are sequentially primary-transferred from the photosensitive drum 1 and are superimposed, collectively on a recording medium P.
Secondary transfer. The transfer unit 4 has an arrow R4
An intermediate transfer belt 4a running in the direction is provided. The intermediate transfer belt 4a of this embodiment is a belt having a circumference of about 440 mm, and includes a driving roller 4b, a secondary transfer facing roller 4c,
It is stretched over three rollers of the driven roller 4d. Further, a pressing roller 4j is provided which is close to the driven roller 4d and presses the intermediate transfer belt 4a against the photosensitive drum 1 and which is retracted so as to take a position where the intermediate transfer belt 4a is separated from the photosensitive drum 1. The intermediate transfer belt 4a runs in the direction of arrow R4 due to the rotation of the drive roller 4b.

Further, at a predetermined position outside the intermediate transfer belt 4a, there is provided a cleaning unit 4e capable of coming in contact with and separating from the surface of the intermediate transfer belt 4a, and removes transfer residual toner remaining after the secondary transfer. The cleaning unit 4e brings the charging roller 4f into contact with the intermediate transfer belt 4a and gives the toner a charge opposite to that at the time of transfer. The toner having the opposite charge is electrostatically attached to the photosensitive drum 1, and
Thereafter, the photosensitive drum 1 is collected by a cleaning device 6 described later.

The method of cleaning the intermediate transfer belt 4a is not limited to the above-described electrostatic cleaning, but may be a mechanical method such as a blade or a fur brush, or a method using both of them.

Further, the toner remaining on the surface of the photosensitive drum 1 after transferring the toner image to the intermediate transfer belt 4a is removed by the cleaning means 9, which contacts the surface of the photosensitive drum 1. Waste toner container 9c scraped off by the cleaning blade 9b
To store. This waste toner container 9c is
a. The amount of waste toner stored in the waste toner container 9c is such that the waste toner container 9c is not filled earlier than the life of the photosensitive drum 1, and the waste toner in the waste toner container 9c is When the life of the drum 1 expires and the process cartridge U is replaced, the replacement process is performed integrally.

The transfer means 6 for transferring the toner images multiplex-transferred onto the intermediate transfer member 4 onto the recording medium P is constituted by a transfer roller in this embodiment. It is wound around the body and provided so as to be movable in the vertical direction in FIG.

While the transfer roller 6 is forming a four-color toner image on the intermediate transfer member 4, that is, while the intermediate transfer member 4 rotates a plurality of times, the transfer roller 6 does not disturb the image so that the image is not disturbed. As shown in FIG.

Then, after the toner image is multiply transferred onto the intermediate transfer member 4 to form a color image, the recording medium P
The transfer roller 6 is moved to an upper position indicated by a chain line by a cam (not shown) in accordance with the timing of transferring the color image to the transfer roller 6. Thereby, the transfer roller 6 is pressed against the intermediate transfer body 4 via the recording medium P with a predetermined pressure. At the same time, a bias voltage is applied to the transfer roller 6, and the toner image on the intermediate transfer member 4 is transferred to the recording medium P.

The transport means 5 for transporting the recording medium P includes a pickup roller 5b, a feed roller 5c1, a retard roller 5c2 for preventing double feed, a transport roller pair 5d, a registration roller pair 5e, a discharge roller pair 5f, and a transport guide 5g.
Consists of

At the time of image formation, the pickup roller 5b is driven and rotated in accordance with the image forming operation, and separates and feeds the recording media P in the paper feed cassette 5a one by one. Then, the recording medium P sent out from the paper feed cassette 5a is guided by the conveyance guide 5g, and reaches the registration roller pair 5g via the conveyance roller pair 5d. During the image forming operation, the registration roller 5e performs a non-rotating operation of keeping the recording medium P stationary and standby and a rotating operation of transporting the recording medium P toward the intermediate transfer body 4 in a predetermined sequence, and performs the next step, transfer. The image in the process is aligned with the recording medium P, and the color image is transferred by the above-described transfer unit.

The recording medium P to which the color image has been transferred is conveyed to the fixing means 7 where the toner image is fixed. The fixing unit 7 includes a fixing roller 7a for applying heat to the recording medium P.
And a pressure roller 7b for pressing the recording medium P against the fixing roller 7a. Both rollers 7a and 7b are hollow rollers, and are rotatably driven with heaters 7a1 and 7b1 therein. The toner image is conveyed while applying heat and pressure to the recording medium P so that the toner image is transferred to the recording medium P.
Established in

Then, the recording medium P on which the toner has been fixed is discharged to the discharge section 8 by a discharge roller pair 5f constituting a conveying means.
Is discharged to

(Developing Cartridge (Developing Apparatus)) Next, the configuration of a developing cartridge for developing a latent image formed on the photosensitive drum 1 will be described.

The image forming apparatus according to the present embodiment has four developing cartridges D (Dy, Dm, Dc, Dc,...) For developing each color of yellow, magenta, cyan, and black in order to form a full-color image. Db). The developing cartridge D is detachably mounted on a rotary unit 11 that rotates about a shaft 10. Then, at the time of image formation, each developing cartridge D is rotated around the shaft 10 while being held by the rotary unit 11. Then, the developing cartridge D containing the predetermined color toner stops at a position facing the photosensitive drum 1. Further, a developing roller to be described later is minutely spaced (approximately 300 μm) with respect to the photosensitive drum 1.
Then, toner is supplied to the electrostatic latent image on the photosensitive drum 1 to develop the electrostatic latent image.

When forming a color image, one of the intermediate transfer members 4
The rotary unit 11 rotates for each rotation, and a magenta developing cartridge Dm containing magenta and a cyan developing cartridge D containing cyan toner
c, the developing process is performed in the order of the yellow developing cartridge Dy containing the yellow toner and the black developing cartridge Db containing the black toner.
The black toner is a magnetic toner, and the other color toners are non-magnetic toners.

FIG. 2 shows a state in which the developing cartridge D (for example, a yellow developing cartridge Dy) is positioned at a developing position facing the photosensitive drum 1 and is stationary.

The developing cartridge D includes a developing roller 1 serving as a toner carrier for supplying toner to the photosensitive drum 1.
2 and a toner storage section 63a for storing toner to be supplied to the developing roller 12. The cartridge frame 63 includes a plurality of frames for supporting the developing roller 12 and a shutter 64 that exposes the developing roller 12 and that can open and close an opening provided in the cartridge frame 63. . Further, a toner stirring member 15 is provided in the toner storage section 63a.

The new developing cartridge is provided with a toner seal 27 so that the toner stored in the toner storing section 63a does not leak. Therefore, before the user attaches the new developing cartridge D to the apparatus main body 30, the user peels off the toner seal 27 and opens the toner storage portion 63a. Thus, the toner in the toner storage section 63a can be supplied to the developing roller 12.

When the driving force is obtained from the apparatus main body 30, the toner stirring member 15 rotates to feed the toner in the toner storage section 63a to the developing roller 12. The developing roller 12 is a rotatable aluminum roller, and a developing blade 16 is pressed against the peripheral surface of the developing roller 12. For this reason, when the developing roller 12 rotates in the counterclockwise direction in FIG. 2, a thin layer of toner is applied to the peripheral surface thereof, and a charge is applied to the toner (frictional charging).

Then, the photosensitive drum 1 on which the latent image has been formed
By applying the developing bias supplied from the apparatus main body 30 to the developing roller 12 facing the toner image, a toner image can be formed on the photosensitive drum 1 according to the latent image.

When the yellow developing cartridge Dy, the magenta developing cartridge Dm, the cyan developing cartridge Dc, and the black developing cartridge Db are respectively moved to the developing positions, each developing roller 12 of each developing cartridge D is attached to the image forming apparatus main body. The developing roller 12 and the like are rotated by being connected to a high-voltage power source and a driving source for each color provided in the developing unit 30, to sequentially and selectively apply a developing bias to each developing cartridge D, and to transmit a driving force.

The yellow developing cartridge D shown in FIG.
y, magenta developing cartridge Dm, and cyan developing cartridge Dc have the same configuration. As shown in FIG. 2, each of the color developing cartridges Dy, Dm, and Dc includes an application roller 19 having a peripheral surface that moves in a direction opposite to the peripheral surface of the developing roller 12. 63A is provided rotatably.

On the other hand, the black developing cartridge Db does not have the coating roller 19. The toner adheres to the developing roller 12 by the magnetic force and adhesive force of a magnet (not shown) incorporated in the inside of the developing roller, and the layer thickness of the toner is regulated by the developing blade 16 which is in contact with the peripheral surface of the developing roller 12 and the toner is charged by friction. An electric charge is generated in the toner.

Next, the toner remaining amount detecting mechanism of the developing unit will be described with reference to FIG. 2, taking the yellow developing unit Dy as a representative.

As shown in FIG. 2, the yellow developing device Dy has a toner stirring member 15 in its toner storage portion 63a.
The stirring member 15 includes a stirring blade 15a and a stirring stay 15b, and stirs the toner inside the toner storage unit 63a and conveys the toner to the developing sleeve 12 side.

The toner storage section 63a faces the vicinity of two upper and lower residual detection windows (window ratios) 81 and 82 which transmit light.
Upper and lower light guides (light-emitting part, light-receiving part) for guiding light to the main body light-emitting part and the main body light-receiving part provided in the apparatus main body 30
84 and 85 are provided, respectively, and constitute an optical circuit of the main body light emitting section → the inside of the developing device → the main body light receiving section.

A residual detection window 8 is provided at the tip of the stirring stay 15b.
Agitating blades 15a for cleaning the first and second cleaning nozzles 82 and 82 are provided to clean the remaining detection windows 81 and 82 and provide an optical path when the amount of toner is small. When there is a large amount of toner in the toner storage section 63a, the stirring blade 15a is immediately covered with the toner even after cleaning the residual detection windows 81 and 82, so that light is not transmitted. Window 8
The time required for transmission through the light emitting elements 1 and 82, that is, the pulse width t shown in FIG.

Incidentally, the black toner developing devices Db and 3
Color (yellow, magenta, cyan) toner developer D
y, Dm, and Dc contain toners having different characteristics, respectively, and the stirring speed of the stirring stay 15b, that is, the stirring cycle is different. Generally, color toner developing units Dy, D
For m and Dc, the stirring speed of the stirring stay 15b is set faster than that of the black toner developing device Db because the coating amount of the color toner on the developing roller 12 is small.

The black toner developing device Db described above has a lower stirring speed than the other color developing devices Dy, Dm, and Dc. It becomes larger than the other color developing units Dy, Dm, Dc. Therefore, the threshold value of the developer remaining amount detection output pulse width cannot be set to the same value for the black toner developing device and the color developing device.

Therefore, in this embodiment, a separate member 86 is provided for the stirring member 15 in the black toner developing device Db, and the light is forcibly shielded by the forcible light shielding portion 87 for a predetermined time width, so that the stirring period T The remaining detectable power pulse width of the developer remaining amount detecting means for making a notice of the remaining amount of the developer by bringing the detectable maximum remaining detective power pulse width close to or matching with the other color developing devices Dy, Dm, Dc. The threshold value can be set to the same value.

The above will be further described with reference to FIGS. 3, 4 and 5.

The time required for the stirring cycle differs depending on the type of toner in each developing device, ie, the stirring speed. In other words, the developing device having a low stirring speed has a larger maximum remaining detection power pulse width detectable in the stirring period T than the developing device having a high stirring speed.

FIG. 3 shows that the maximum remaining detection power pulse width detectable in the stirring cycle of the black toner developing device Db is 900 ms, and the maximum detectable pulse width in the color developing devices Dy, Dm, and Dc having a faster stirring period is the maximum. The remaining detection pulse width is 700 ms,
The case where the threshold value of the output pulse width of the developer remaining amount detecting means for performing the developer remaining amount notice is set to 500 ms is shown.

In this case, for example, if only the difference in the stirring speed is described, the remaining toner amount in the black toner developing device Db is
Even if it is the same amount as other color developing units Dy, Dm, Dc,
Even if the position of the stirring member 15 is the same in black and color when the stirring blade 15a cleans the residual detection windows 81 and 82 and covers the residual detection windows 81 and 82 due to the difference in the stirring speed, the black toner developing device Db is Transmit a lot of light. Therefore, the black toner developing device Db
In the case of (2), when the amount of toner is reduced, "the remaining toner is low" is displayed quickly.

In the case where the stirring speed is the same for black and color and the toner characteristics, that is, only the fluidity, are different, the toner amount decreases. When the toner amounts are the same for both black and color, the stirring blade 15a remains. Even if the inspection windows 81 and 82 are cleaned and light can pass therethrough, the color toner having excellent fluidity can be obtained only by slightly rotating the stirring member 15.
However, the black toner having poor fluidity covers the residual detection windows 81 and 82 only at the position where the stirring member 15 has advanced considerably.

In other words, when the toner amount is the same, the black developing device Db is more effective than the color developing devices Dy, Dm and Dc.
A lot of light is transmitted. For this reason, "the remaining toner is low" is displayed quickly. To solve this, the threshold value of the black toner developing device must be changed to 850 ms, that is, a threshold value different from that of the color developing device must be set.

Here, the type of the developer, that is, whether the developer is a magnetic substance or a non-magnetic substance, is one component or two components, and the stirring speed, that is, is displayed at a fixed time without being influenced by the stirring cycle. As shown in FIGS. 4 and 5, another member 86 is provided on the stirring member 15 of the black toner developing device Db, and when the rotation of the stirring member 15 is advanced to a predetermined position,
By forcibly shading the light with a predetermined time width by the forcible shading section 87 by the separate member 86, the maximum remaining detection power pulse width detectable in the stirring period T is reduced as shown in FIG. In this case, the pulse width becomes smaller than the remaining detection power pulse width, so that the same threshold value as the other color developing units Dy, Dm, and Dc, that is, the threshold value can be set to the same set value of 500 ms.

Thus, a complicated operation for setting different threshold values for each developing device can be omitted, and the threshold values can be set easily.

Embodiment 2 Next, a second embodiment of the present invention will be described with reference to FIG. In the embodiments after this embodiment, members having the same functions are denoted by the same reference numerals.

In the present embodiment, there is a difference in the toner characteristics and the developer stirring speed, and the image forming apparatus has a plurality of developing devices which constitute the optical axis L of the light emitting / receiving portion at a position deviated from the stirring rotation center 88. In FIG. 7, as shown in FIG.
The stirring blade 15a of the stirring member 15 is extended,
By performing the forced shading as described above, the residual detection pulse width t detectable in the stirring period T can be brought close to or matched with another developing device, and the threshold value of the output pulse width of the developer remaining amount detecting means can be reduced. It is possible to set the same value.

Embodiment 3 Next, a third embodiment of the present invention will be described with reference to FIG.

In the present embodiment, there is a difference in the toner characteristics and the developer stirring speed, and in the image forming apparatus having a plurality of developing devices which constitute the optical axis L of the light emitting and receiving portion at a position deviated from the stirring rotation center 88. As shown in FIG. 8, the stirring stay 15b of the stirring member 15 is extended to form a forced light shielding unit 87, and the residual light detection pulse width t detectable in the stirring cycle T is made closer to another developing device by performing the forced light shielding. Alternatively, the threshold value of the output pulse width of the developer remaining amount detection means can be set to the same value.

Embodiment 4 Next, a fourth embodiment of the present invention will be described with reference to FIGS.

In the present embodiment, there is a difference in the characteristics of the toner and the developer stirring speed, and the configuration of the developer remaining amount detecting means is located at the stirring rotation center 88 near the optical axis L of the light emitting and light receiving portion. In an image forming apparatus having a plurality of developing devices having openings 89 in the stirring stay 15b for light transmission, a separate member 86 having an angle with respect to the stirring member 15 and having a light shielding ability is provided, and a forced light shielding portion 87 is provided. By doing so, the stirring cycle T
It is possible to make the residual detection pulse width t detectable with the other developing devices close to or match the other developing devices, and to set the threshold value of the output pulse width of the developer remaining amount detecting means to the same set value.

Embodiment 5 Next, a fifth embodiment of the present invention will be described with reference to FIG.

In the present embodiment, there are differences in the characteristics of the toner and the developer stirring speed, and the structure of the developer remaining amount detecting means is such that the stirring rotation center 88 is located near the optical axis L of the light receiving and light receiving portion.
, And an opening 8 in the stirring stay 15b for light transmission.
In the image forming apparatus having a plurality of developing devices having the number 9, the stirring stay 15b is bent so as to have an angle to form the forced light shielding portion 87, so that the remaining detection power pulse width t detectable in the stirring cycle T can be changed to another. The threshold value of the output pulse width of the developer remaining amount detecting means can be set to the same value as that of the developing device.

Embodiment 6 Next, a sixth embodiment of the present invention will be described with reference to FIG.

In this embodiment, there are differences in the characteristics of the toner and the developer stirring speed, and the structure of the developer remaining amount detecting means is such that the stirring rotation center 88 is located near the optical axis L of the light receiving and light receiving portion.
In the image forming apparatus having a plurality of developing devices provided with the opening 89 in the stirring stay 15b so as to transmit light, the width of the opening 89 is adjusted by another member 86, that is, the stirring period is reduced. The light transmission time width at T, that is, the forced light-shielding time width can be adjusted, and the remaining detection power pulse width t detectable in the stirring period T can be brought close to or matched with another developing device, and the remaining amount of developer can be adjusted. The threshold value of the output pulse width of the detection means can be set to the same value.

Embodiment 7 Next, a seventh embodiment of the present invention will be described with reference to FIG.

In the present embodiment, there is a difference in the characteristics of the toner and the developer stirring speed, and the structure of the developer remaining amount detecting means is located at the stirring rotation center 88 near the optical axis L of the light emitting and light receiving portion. In order to transmit light, the opening 89 is stirred with a stirring stay 1.
5b, the width of the opening 89 is adjusted by extending the stirring blade 15a.
That is, by narrowing the width, the light transmission time width in one stirring period T, that is, the forced light shielding time width can be adjusted, so that the remaining detection power pulse width t detectable in the stirring period T is made closer to another developing device. Alternatively, the thresholds of the output pulse widths of the developer remaining amount detecting means can be set to the same set values.

Embodiment 8 Next, an eighth embodiment of the present invention will be described with reference to FIG.

In the present embodiment, as shown in FIG. 14, there are differences in the characteristics of the toner and the stirring speed of the developer.
In an image forming apparatus having a plurality of developing devices in which an opening 89 is provided in the stirring stay 15b so as to transmit light, the stirring stay 15b
By adjusting, ie, narrowing, the width of the opening 89, the light transmission time width in the stirring period T, that is, the forced light shielding time width can be adjusted, and the remaining detection power pulse width t detectable in the stirring period T can be adjusted. It is possible to approach or match another developing device, and to set the threshold value of the output pulse width of the developer remaining amount detecting means to the same set value.

[0087]

As is apparent from the above description, according to the developing device and the image forming apparatus of the present invention, the stirring member in the developing container has the light shielding member provided with the integral or separate forced light shielding portion. However, by setting the detection light forced light-shielding time width for each developing device by the forced light-shielding portion, when the types of the developers of the plurality of developing devices are different, or when the stirring period of the stirring member is different, In the above, the threshold value of the output pulse width of the developer remaining amount detecting means for performing the developer remaining amount notice can be set to the same value and simplified, complicated work can be omitted, and the total amount of toner can be detected with high accuracy. I was able to.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a multicolor image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional configuration diagram illustrating the color toner developing device of FIG. 1;

FIG. 3 is a graph showing a relationship between a residual toner amount in a conventional cartridge and an output pulse width of a residual toner sensor.

FIG. 4 is a cross-sectional configuration diagram illustrating the developing device for black toner of FIG. 1;

FIG. 5 is a perspective view illustrating a main part of the developing device of FIG. 4;

FIG. 6 is a graph showing the relationship between the remaining toner amount in the cartridge and the output pulse width of the remaining toner sensor in which the present invention is implemented.

FIG. 7 is a perspective view of a main part showing a developing device of a second embodiment.

FIG. 8 is a perspective view of a main part showing a developing device according to a third embodiment.

FIG. 9 is a perspective view of a main part showing a developing device of a fourth embodiment.

FIG. 10 is a sectional view illustrating a developing device according to a fourth embodiment.

FIG. 11 is a perspective view of a main part showing a developing device according to a fifth embodiment.

FIG. 12 is a perspective view showing a main part of a developing device according to a sixth embodiment.

FIG. 13 is a perspective view showing a main part of a developing device according to a seventh embodiment.

FIG. 14 is a perspective view showing a main part of a developing device according to an eighth embodiment.

FIG. 15 is a configuration diagram illustrating an example of a conventional image forming apparatus.

16 is a partial perspective view illustrating a developing device of the image forming apparatus of FIG.

17 is a waveform chart showing output pulses of a developer remaining amount detecting mechanism of the developing device of FIG.

[Explanation of symbols]

 Reference Signs List 15 Stirring member 15a Stirrer blade 15b Stirring stay 63 Developing container 84 Upper light guide unit (light emitting unit) 85 Lower light guide unit (light receiving unit) 86 Separate member (light shielding member) 87 Forced light shielding unit 89 Opening D Developing cartridge (developing device) )

Claims (26)

[Claims] 1. A developing container for storing a developer, a stirring member rotating in the developing container and stirring the developer, and a photodetection type developing device for detecting a remaining amount of the developer in the developing container. An image forming apparatus having a plurality of developing devices of different colors, wherein the stirring member has a light shielding member having an integral or separate forced light shielding portion; An image forming apparatus for setting a detection light forcible light shielding time width for each developing device. 2. The developing device according to claim 1, wherein a threshold of an output pulse width of said developer remaining amount detecting means for performing a developer remaining amount notice is forcibly light-shielded for a predetermined time width by said forced light-shielding section. 2. The image forming apparatus according to claim 1, wherein the setting values are set to the same values. 3. The stirring member has a stirring blade at one end, and the light blocking member is provided on a side opposite to the stirring blade with respect to a stirring rotation center axis of the stirring member. Item 3. The image forming apparatus according to item 1 or 2. 4. The image forming apparatus according to claim 1, wherein the forced light-shielding time width of the plurality of developing devices differs depending on the type of developer. 5. The image forming apparatus according to claim 1, wherein the forced light blocking time width of the plurality of developing devices varies depending on the stirring speed of the stirring member. 6. The image forming apparatus according to claim 1, wherein the stirring blade provided on the stirring member is a light shielding member having the forced light shielding unit. 7. The image forming apparatus according to claim 1, wherein a stirring stay for holding a stirring blade provided on the stirring member is a light shielding member having the forced light shielding unit. 8. A light detecting system including a developing container containing a developer, a plurality of developing devices of different colors including a stirring member in the developing container for stirring the developer, a light emitting unit and a light receiving unit. An image in which an agitating rotation center of the agitating member is formed near the optical axis of the light emitting unit and the light receiving unit, and an opening for transmitting light is provided in the agitating member. The image forming apparatus according to claim 1, wherein forcible shading is performed by providing an angled member near an opening of the stirring member. 9. A threshold value of an output pulse width of said developer remaining amount detecting means for giving a developer remaining amount notice is set by forcibly shading for a predetermined time width by using a member having said angle as a forced light shielding portion. 9. The image forming apparatus according to claim 8, wherein the same setting value is set for each of the developing devices. 10. A member having the angle by bending a portion of the stirring stay provided on the stirring member, which supports a stirring blade, located in the vicinity of the opening. Image forming device. 11. A light detection system including a developing container containing a developer, a plurality of developing devices of different colors including a stirring member in the developing container for stirring the developer, and a light emitting unit and a light receiving unit. An image in which a stirring rotation center of the stirring member is formed near the optical axis of the light emitting unit and the light receiving unit, and an opening for transmitting light is provided in the stirring member. An image forming apparatus, wherein forced light shielding is performed by adjusting a width of the opening. 12. A threshold value of an output pulse width of said developer remaining amount detecting means for giving a developer remaining amount notice is set to a predetermined time width,
12. The image forming apparatus according to claim 11, wherein the forcible shading is performed to set the same set value in each of the developing devices. 13. The apparatus according to claim 11, wherein the width of the opening is adjusted by a member different from the stirring member.
Or 12 image forming apparatuses. 14. The image forming apparatus according to claim 11, wherein the width of the opening is adjusted by a stirring blade attached to the stirring member. 15. The image forming apparatus according to claim 11, wherein the width of the opening is adjusted by a stirring stay attached to the stirring member. 16. The developing device includes upper and lower window members provided in the developing container so as to be able to transmit light, the stirring member has stirring blades for cleaning the upper and lower window members, and The developer remaining amount detecting means of the detection method has a light emitting unit and a light receiving unit attached to the apparatus main body near the window member, and when the window member is cleaned by the stirring blade, the light emitting unit The image forming apparatus according to claim 1, wherein the emitted light is received by the light receiving unit. 17. A light detecting system for detecting a remaining amount of the developer in the developing container, comprising: a developing container for storing the developer; and a stirring member in the developing container for stirring the developer. A developing device used in an image forming apparatus provided with a developer remaining amount detecting unit, wherein the stirring member has a light shielding member having an integral or separate forced light shielding portion. 18. The stirring member has a stirring blade at one end, and the light shielding member is provided on the opposite side of the stirring blade with respect to a stirring rotation center axis of the stirring member. Item 17. A developing device. 19. The developing device according to claim 17, wherein a stirring blade of the stirring member is extended to be a light shielding member having the forced light shielding portion. 20. The developing device according to claim 17, wherein a stirring stay for holding a stirring blade of said stirring member is extended to be a light shielding member having said forced light shielding portion. 21. A developing device for use in an image forming apparatus provided with a light detection type developer remaining amount detecting unit including a light emitting unit and a light receiving unit, comprising: a developing container for storing a developer; A stirring member provided to stir the developer, a stirring rotation center of the stirring member provided near the optical axis of the light emitting unit and the light receiving unit, and an opening for light transmission provided in the stirring member. The developing device according to claim 1, wherein an angled member is attached near an opening of the stirring member to form a forced light shielding unit. 22. The stirrer provided on the stirrer, the stirrer supporting the stirrer blade, wherein a portion located near the opening is bent to form a member having the angle. Developing device. 23. A developing device used in an image forming apparatus provided with a light detection type developer remaining amount detecting unit including a light emitting unit and a light receiving unit, wherein a developing container for storing a developer and a developing container are provided. A stirring member provided to stir the developer, a stirring rotation center of the stirring member provided near the optical axis of the light emitting unit and the light receiving unit, and an opening for light transmission provided in the stirring member. The forcible light shielding is performed by adjusting the width of the opening. 24. The apparatus according to claim 23, wherein the width of the opening is adjusted by a member different from the stirring member.
Developing device. 25. The image forming apparatus according to claim 23, wherein the width of the opening is adjusted by a stirring blade attached to the stirring member. 26. The developing device according to claim 23, wherein the width of the opening is adjusted by a stirring stay attached to the stirring member.