JP3266447B2 - Image forming device - Google Patents

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, and more particularly to an improvement in the performance of a developer amount detecting mechanism in a developer container.

[0002]

2. Description of the Related Art Conventionally, as a method of detecting the amount of toner in a toner container, which is a developer container of a developing device, a transparent window member is provided in the toner container, and the window member is transmitted through the window member to optically detect the remaining amount of toner. The method of detecting was used. In order to reliably detect the remaining amount of toner by this method, it is necessary to appropriately clean the window member. As a cleaning method, a stirring blade in a toner container is generally used. Further, in the case of a developing cartridge, a shutter that protects a user from touching a toner carrier, which is a developer carrier, before mounting on the image forming apparatus main body, and is opened after mounting is generally provided. At that time, when the shutter or the like is on the optical path outside the toner container, a notch or an opening is formed to secure the optical path.

[0003]

In order to reliably detect the remaining amount of toner in the toner container, the optical path of the optical detection means must be arranged so as to pass through the lower surface of the toner container.
The reason for this is that the optical detection means determines the absence of toner based on the light transmission time from the time when the stirring member in the toner container cleans the window member to the time when the toner falls on the window member again. At that time, it is necessary to form an opening so as not to block the optical path even in the shutter protecting the developing device.

[0004] However, scattered toner or foreign matter from the outside accumulates on the shutter, drops from the opening, and accumulates on the optical detecting means. On the optical path of the optical detection means provided in the image forming apparatus, scattered toner and the like are gradually accumulated even after the replacement of the developing cartridge, which is a consumable, and as a result, the amount of light on the light emission side decreases, or light is not received. There was a problem that the detection became unstable and the function was erroneously detected or the function stopped.

Accordingly, a first object of the present invention is to provide a developing cartridge capable of preventing erroneous detection or function stop due to accumulation of scattered toner or foreign matter in an optical detecting means for detecting the remaining amount of developer in a developer container. An object of the present invention is to provide an image forming apparatus including:

A second object of the present invention is to provide an image forming apparatus provided with a developing cartridge capable of stabilizing the light emission amount and light receiving accuracy of the optical detecting means.

A third object of the present invention is to provide an image forming apparatus provided with a developing cartridge which does not stain the optical path of the optical detecting means with scattered toner or foreign matter.

[0008]

The above object is achieved by an image forming apparatus according to the present invention. In summary, the present invention provides:
A cartridge main body including a developer accommodating portion for accommodating a developer provided with a first window capable of transmitting light and a rotatable developer carrier, the cartridge main body being movable to a position covering the developer carrier and an exposed position; When the relative position with respect to the cartridge body reaches a predetermined position, a light-transmissible second facing the first window.
A rotating member for holding a plurality of detachable developing cartridges having a protective member provided with a window, and an image carrier on which a latent image to be developed by the developer is formed. It has a function to detect the amount of developer in the developer container through the window, and the rotation of the rotating body switches the developer carrier facing the image carrier, so that the developer contained in each developing cartridge is switched. In an image forming apparatus for forming an image on an image carrier, the protection member is fixed to the rotating body in a state where the developing cartridge is mounted on the rotating body, and the cartridge body is configured to rotate the rotating body. Irrespective of the position in the direction, it is configured to rotate with respect to the rotating body so as to maintain a constant posture, and the relative position between the cartridge body and the protection member caused by the rotation of the rotating body. Cleaning member provided in the cartridge body by a change in an image forming apparatus characterized by rubbing the second window.

[0009]

[0010]

[0011]

[0012]

[0013]

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a reference example of an image forming apparatus to which the present invention can be applied will be described in more detail with reference to the drawings.

"Overall Description of Image Forming Apparatus" First, an overall configuration of a color image forming apparatus will be schematically described with reference to FIG. FIG. 6 is an explanatory diagram of the overall configuration of a laser beam printer which is one mode of the color image forming apparatus.

As shown in FIG. 6, the present apparatus winds a transfer material 22 fed from a feed unit 21 around a transfer drum 23, and loads the transfer material 22 with four rotatable developing units. The toner image developed by the forming unit is transferred in a multiplex manner to form a color image. Then, the transfer material 22 is fixed to the fixing unit 26.
Then, the color image is fixed on the transfer material 22, and is discharged by a discharge roller pair 27 to a discharge section 28 in the upper portion of the apparatus.

The rotatable developing device is provided in the main assembly 29 of the apparatus.
Are configured to be individually attachable and detachable.

Exposure to the image forming unit is performed by the scanner unit 3
Sent from 0. That is, when an image signal is given to the laser diode, the laser diode irradiates the polygon mirror 30a with image light corresponding to the image signal. The polygon mirror 30a is rotated at a high speed by a scanner motor, and the image light reflected by the polygon mirror 30a is radiated from the exposure unit of the image carrier unit via the imaging lens 30b and the reflection mirror 30c to selectively cause the image carrier. Is configured to be exposed.

Next, the structure of each section of the image forming section will be sequentially described in detail.

[Feeding Unit] The feeding unit 21 feeds the transfer material 22 to the image forming unit, and loads a paper feed cassette 21a containing a plurality of transfer materials 22 into the inner bottom of the apparatus main body 29. I do. During image formation, the feed roller 21b is driven and rotated in accordance with the image forming operation, and the transfer material 22 in the cassette 21a is rotated.
Are separated and fed one by one, guided by a guide plate 21c, and fed to a transfer drum 23 through a registration roller 21e.

[Transfer Drum] The transfer drum 23 winds the fed transfer material 22 and rotates in the direction of the arrow in FIG. 6 to transfer each color toner to the transfer material 22.

The transfer drum 23 according to this embodiment has a diameter of about 1 mm.
An elastic layer 23b such as sponge or rubber is formed on the outer circumference of a 60 mm aluminum cylinder 23a, a resistance layer 23c is formed on the outer circumference thereof, and a dielectric layer 23d is formed on the outermost circumference. The transfer drum 23 is rotatably supported by a fixed shaft 23e, and transmits a driving force of a drive motor to a gear (not shown) fixed to the transfer drum 23, so that the transfer force in the direction of the arrow in FIG. It is configured to rotate.

A gripper 23f is provided at a predetermined position on the outer periphery of the transfer drum 23 so as to grip the leading end of the fed transfer material 22. Further, the electrostatic attraction roller 2
3 g is provided on the outer periphery of the transfer drum 23 so as to be able to contact and separate therefrom.
The transfer material 22 is transferred to the electrostatic attraction roller 23 g and the transfer drum 2.
3 and is pressed against the outer periphery of the transfer drum 23 so as to be sandwiched between the transfer drum 23 and the electrostatic attraction roller 23 g and the transfer drum 23.
A voltage is applied between the transfer material 22 and the transfer material 22 which is a dielectric, and induces electric charges in the dielectric layer 23 d of the transfer drum 23, and the transfer material 22 is electrostatically attracted to the outer periphery of the transfer drum 23. are doing.

The method for adsorbing the transfer material 22 to the transfer drum 23 is not limited to the above-mentioned electrostatic attraction, but may be a suction method using air or the like.

"Image Carrier Unit" The image carrier 24a according to the present embodiment is formed by applying an organic photoconductor layer to the outer peripheral surface of an aluminum cylinder having a diameter of about 40 mm, and the rotation axis is set to the image carrier unit cover 24. Is rotatably supported. A cleaner 2 is provided around the image carrier.
4c, a primary charging means 24b is disposed, and by transmitting a driving force of a driving motor (not shown) to one end of the rotating shaft, the image carrier 24a is rotated in the direction of the arrow in FIG. I try to make it. This unit is detachable from the apparatus main body and can be easily replaced according to the life of the image carrier.

"Charging means" The charging means 24b is disclosed in
The method uses a so-called contact charging method as disclosed in JP-A-149669, in which a conductive roller is brought into contact with an image carrier 24a, and a voltage is applied to the conductive roller to form a surface of the image carrier 24a. Is charged uniformly.

"Cleaning means" The cleaning means is a developing means
After the toner visualized in 4a is transferred to the transfer material 22, the toner remaining on the image carrier 24a is cleaned.
Waste toner transport screw 2 passed through waste toner container
4d, the toner is sent to the waste toner container attached to the side of the main body, and when the waste toner container is full of waste toner, it is removed and replaced.

"Developing Means" The developing means 100 includes a magenta, cyan, yellow,
Four developing devices, that is, developing cartridges 100M, 100C, 100, and 100K capable of developing each color of black
It has.

These four developing units 100M, 100C,
100Y and 100K are arranged rotatably about the shaft 14, and the center of each developing unit rotates in conjunction with a rotation gear arranged on the outer periphery of the revolving gear, so that the posture is always kept constant. .

When forming an image, a developing device 100 corresponding to each of magenta, cyan, yellow and black color development
M, 100C, 100Y, and 100K rotate around the shaft 14, a predetermined developing device stops at a position facing the image carrier unit, and the developing sleeve is moved to the image carrier 24a.
Are positioned so as to face each other with a minute interval (about 300 μm), and then a visible image is formed by the toner on the image carrier 24a. The toner in the container corresponding to the color to be developed is sent to the application roller 5 by the feeding mechanism, and a thin layer of the toner is applied to the outer periphery of the rotating application roller 5 and the rotating developing roller 3 by the blade 4, and a charge is applied to the toner. (Frictional charging). By applying a developing bias between the developing roller 3 and the image carrier 24a on which the latent image is formed, toner development is performed on the image carrier 24a in accordance with the latent image.

The developing roller 3 of each developing device is connected to a high-voltage power supply for developing each color provided in the apparatus main body 29 when each developing device is rotated to the developing position, and is selectively provided for each color development. A voltage is applied.

"Fixing section" The fixing section 26 is provided with the developing means 10
0, the image formed on the transfer material 22 wound around the transfer drum 23 is fixed. As shown in FIG. 6, a driving roller 26a that is driven and rotated is pressed against the transfer roller 26a to apply heat and pressure to the transfer material 22. And a fixing roller 26b to be applied. That is, the transfer material 22 peeled off from the transfer drum 23 is conveyed by the driving roller 26a when passing through the fixing unit 26, and heat and pressure are applied by the fixing roller 26b. As a result, the image forming toner is transferred to the transfer material 2
Fix to 2.

The cleaning member 26c is in contact with the fixing roller 26b, and the toner adhered to the fixing roller 26b is removed by the cleaning member 26c.

"Image Forming Operation" Next, the operation in the case where an image is formed by the above-configured apparatus will be described.

First, the feed roller 21b shown in FIG. 6 is rotated to separate one transfer material 22 in the paper feed cassette 21a.
The sheet is fed to the transfer drum 23. The transfer drum 23 rotates in the direction of the arrow in FIG. 6 to grip the leading end of the fed transfer material 2 with the gripper 23f, and electrostatically attracts the transfer material 22 to the peripheral surface thereof.

The image carrier 24a is rotated in the direction of the arrow in FIG. 6 in synchronization with the rotation of the transfer drum 23, and the surface of the image carrier 24a is uniformly charged by the charging means 24b. Irradiation is performed to form a magenta latent image on the image carrier 24a. The magenta developing device 100M is driven simultaneously with the formation of the latent image, and the image carrier 24a is driven.
Image carrier 2 so that magenta toner adheres to the upper latent image.
A voltage having substantially the same potential as the charging polarity of the toner 4a is applied for magenta development, and a voltage having a polarity opposite to that of the toner is applied to the transfer roller 3 to transfer the toner on the image carrier 24a to the transfer drum 2.
3 is transferred to the transfer material 22 above.

When the transfer of the magenta toner is completed as described above, the next developing device is rotated and moved to the image carrier 24a.
In the same manner as magenta, cyan, yellow, and black latent images and toner transfer are sequentially performed to form a color image on the transfer material 22.

After the image is formed, the transfer material 22 is separated from the transfer drum 23 and is conveyed to the fixing unit 26.
After the toner is fixed, the sheet is discharged to the discharge tray 28 by the discharge roller pair 27, and the image formation is completed.

Next, the developing cartridge will be described in detail with reference to FIGS. Since the developing cartridges of the respective colors have the same configuration, they will be described simply as developing cartridges.

The developing cartridge 100 includes the developing container 1
And a toner container 2 which is a developer container for storing the toner.
A blade 4 for applying a thin layer of toner and applying a charge to the developing roller 3 which is a developer carrier rotatably supported on the developing container 1; and a supply roller 5 for supplying toner to the developing roller 3. And a stirring member 6 rotatably supported by the toner container 2 and supplying the toner into the developing container.
And the general configuration. This developing cartridge is rotatably supported with its outer periphery covered so as to be sandwiched by protective container shutters 7a and 7b serving as protective members.

An opening 8 for securing an optical path is formed in the protective container shutter 7a, and a foreign matter blocking member 9 is attached to the opening 8 from outside the shutter 7a.

On the wall of the toner container 2, window members 10a and 10b capable of transmitting light are formed on opposing surfaces passing through the rotation center of the stirring member 6, respectively.

On the other hand, the main body 29 of the image forming apparatus (see FIG. 6) is provided with optical detecting means by the light emitting element 11a and the light receiving element 11b at a position where the light can be transmitted through the window members 10a and 10b into the toner container. An optical path is formed through the blocking member 9 and the window members 10a and 10b.

As a result, even if scattered toner or foreign matter from the outside accumulates on the shutters 7a and 7b, the foreign matter blocking member 9 prevents falling and depositing on the light emitting element 11a from the opening 8. As a result, the scattered toner stays in the developing cartridge, and even after the consumable developing cartridge can be replaced, the operation of the optical detecting means in the image forming apparatus main body can be normally maintained.

Since the foreign matter blocking member 9 must transmit light, it is preferable that the foreign matter blocking member 9 be colorless and transparent, such as a PET sheet, and have a smooth surface. Also, a colorless and transparent resin such as acrylic or PS is effective.

Embodiment 1 Next, Embodiment 1 of the image forming apparatus according to the present invention will be described with reference to FIGS. The present embodiment is characterized in that the foreign matter blocking member in the above reference example is provided inside the toner container, and a foreign matter scraping member is additionally provided.

As shown in FIGS. 3 and 4, the shutter 7
a foreign matter blocking member 9 covering the opening 8 of FIG. 1a is adhered to the inside of the shutter 7a to form a light transmissive window, and further a foreign matter scraping for scraping foreign matter adhered on the inner surface of the foreign matter blocking member 9 is performed. The member 12 was attached to the toner container 2.

The plurality of developing cartridges 100
Is an axis 14 parallel to the image carrier axis 13 as shown in FIG.
The developing device selecting mechanism 15 is a rotating body that rotates around the center of the developing device. The developing device selecting mechanism 15 has shutters 7 a and 7.
b is fixedly supported.

On the other hand, the developing means including the developing container 1 and the toner container 2 is configured to perform a rotation operation in order to keep its posture constant.

As a result, the developing means rotates with respect to the outer peripheral shutters 7a and 7b at the time of development switching, and at this time, the scraping member 12, which is a cleaning member attached to the toner container 2, is moved inside the shutter 7a. Can be cleaned by rubbing at least once by the time of next development.

With the above configuration, the light transmittance of the foreign matter blocking member 9 is reduced due to the adhesion of the scattered toner. Light transmission can be easily recovered, and the normal operation of the optical detection means 11a and 11b can be maintained.

As the scraping member 12, a thin and soft sheet such as PET or urethane, a brush, urethane foam, or the like is effective.

The present invention is very effective especially for a long-life developing cartridge, considering that a large amount of scattered toner adheres to the foreign matter blocking member 9.

[0054]

As is apparent from the above description, according to the present invention, the protective member is fixed to the rotating body in a state where the developing cartridge is mounted on the rotating body, and the cartridge body is rotated in the rotating direction of the rotating body. The cleaning unit is configured to rotate with respect to the rotating body so as to maintain a constant posture regardless of the position of the cartridge, and the cleaning provided on the cartridge body due to a change in the relative position between the cartridge body and the protection member caused by the rotation of the rotating body. Since the member is configured to rub against the light-transmissible second window provided on the protection member, the second member provided on the protection member of the developing cartridge can be provided without a special structure for moving the cleaning member. 2 can automatically clean windows. Therefore, according to the present invention, it is possible to prevent erroneous detection or function stop due to accumulation of scattered toner or foreign matter on the optical detection means.
Further, it is possible to stabilize the amount of light emitted from the optical detecting means and the accuracy of light reception, and furthermore, the optical path of the optical detecting means is not contaminated by scattered toner or foreign matter, and therefore, the developer in the developer container The amount can be accurately detected, and good image formation can be maintained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a reference example of a developing cartridge configured according to the present invention.

FIG. 2 is a partial perspective view of the developing cartridge of FIG.

FIG. 3 is a sectional view showing an embodiment of the developing cartridge according to the present invention.

FIG. 4 is a partial perspective view of the developing cartridge of FIG. 3;

FIG. 5 is a cross-sectional view showing a state in which the developing cartridge of FIG. 3 is carried by a developing device selecting mechanism.

FIG. 6 is an overall configuration diagram illustrating an example of a color image forming apparatus in which the present invention is implemented.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Developing container 2 Toner container (developer container) 3 Developing sleeve (developer carrying member) 7a, 7b Shutter (protection member) 8 Opening 9 Foreign matter blocking member 10a, 10b Window member 11a Light emitting element (optical detection means) 11b Light receiving Element (optical detection means) 12 Scraping member (cleaning member) 15 Developing device selecting mechanism (rotary body) 100 Developing cartridge

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 15/08-15/095

Claims (1)

(57) [Claims] 1. A cartridge main body having a first light-transmitting window and a developer accommodating portion for accommodating a developer, and a rotatable developer carrier, wherein the cartridge body has a position covering the developer carrier and a position exposing the developer carrier. A plurality of detachable developing cartridges having a movable member which is movable and has a second window capable of transmitting light which faces the first window when the relative position with respect to the cartridge body becomes a predetermined position; And a function of detecting the amount of developer in the developer accommodating portion through the first and second windows. And an image forming apparatus that switches the developer carrier facing the image carrier by rotating the rotating body to form an image on the image carrier with the developer contained in each of the developing cartridges. Times The protection member is fixed to the rotating body in a state of being mounted on the body, and the cartridge main body is fixed with respect to the rotating body so as to maintain a constant posture regardless of the position in the rotating direction of the rotating body. The cleaning member provided on the cartridge body rubs the second window due to a change in the relative position between the cartridge body and the protection member caused by the rotation of the rotating body. Characteristic image forming apparatus.