JPH07104618A - Image forming device - Google Patents

Abstract

PURPOSE:To accurately detect the exchange time of a photoreceptor drum and a cartridge by detecting the driving time of an image carrier so that the life thereof may be detected. CONSTITUTION:The integrated time for driving a main motor 2 is counted in a DC controller 20. When the counted time exceeds a fixed time, a motor(or a solenoid) 23 is driven so as to slightly rotate a disk 15. Therefore, the image forming device is driven and the main motor 22 is driven, so that the disk 15 is gradually rotated according to the driving time and an aperture is rotated to a specified position. A photocoupler 18 detects the effect and transmits it to the DC controller 20. When the fixed time for driving the photoreceptor drum rotated by the main motor 22 elapses, the DC controller 20 detects the effect and outputs a signal showing that the photoreceptor drum ends its life.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for rotating an image carrier to form an image on a recording medium, and more particularly to an image forming apparatus for detecting the life of an image carrier or a cartridge.

[0002]

2. Description of the Related Art An image forming apparatus such as a printer forms a latent image by selectively exposing a uniformly charged photosensitive drum to form a latent image, and the latent image is visualized with a toner. An image is recorded by transferring the image to a recording medium. In such an apparatus, when it is used for a long period of time, the photosensitive drum is scraped off, and so-called fog or the like occurs during image formation.

Therefore, conventionally, as a means for informing the life of the photoconductor drum, an analog counter system has generally been used in which the rotation of the photoconductor drum is decelerated by a plurality of stages of gears to rotate a disk.

Further, in the image forming apparatus, toner must be replenished each time it runs out, but this toner replenishment work is not only troublesome, but it can also become dirty. In addition, maintenance of each member can be performed only by a specialized service person, which often causes inconvenience to the user.

Therefore, the photosensitive drum, the charging device, the developing device, the cleaning unit, and the like are integrally formed into a cartridge so that the user can load the cartridge into the main body of the apparatus to replenish toner and extend the life. It has been put into practical use that the parts of the photoconductor drum that have reached can be replaced and the maintenance is easy. In an image forming apparatus equipped with such a cartridge, it is necessary to replace the cartridge when the toner in the cartridge is used up.

Therefore, conventionally, as a means for notifying the replacement of the cartridge, a method of detecting the amount of the residual toner in the developing device or the amount of the waste toner removed by the cleaning portion by the change of the electrostatic capacity is generally used. ing.

[0007]

However, in the analog counter method, there is a problem that the gear reduction ratio has to be increased and the cost is increased. In addition, this deceleration mechanism must be provided on the cartridge side in the system in which the cartridge is mounted, and there is a problem that the cost of the cartridge itself is increasing.

Further, in the method of detecting the amount of toner in the developing device, for example, when image recording with a small print ratio is performed, the abrasion of the photosensitive drum becomes large after the prescribed standard number of prints has passed. However, there is a problem in that the toner consumption amount is small and the toner amount more than the specified amount remains in the developing device.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to form an image capable of accurately detecting the replacement time of the photosensitive drum or the cartridge without increasing the cost. It is intended to provide a device.

[0010]

A typical constitution according to the present invention for achieving the above object is to provide an image carrier, a developing means for forming a toner image on the image carrier, and an image carrier. When a cleaning unit for removing residual toner, an image carrier driving time detecting unit for detecting that the driving time of the image carrier exceeds a certain time, and a signal from the image carrier driving time detecting unit are input. It is characterized in that a life detecting means for outputting a life detecting signal of the image carrier is provided.

[0011]

In the above construction, since the life is detected by detecting the driving time of the image carrier, the life can be accurately determined. Further, since no special deceleration mechanism is required for detecting the drive time, no increase in cost will occur.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, as an embodiment of the present invention, an image forming apparatus in which a process cartridge can be mounted will be specifically described with reference to the drawings.

[First Embodiment] FIG. 1 is a structural explanatory view of an image forming apparatus in which a process cartridge is mounted, and FIG. 2 is a structural explanatory view of a process cartridge. Here, as the order of description, the overall configuration of the image forming apparatus in which the process cartridge is mounted will be described, and then the lifetime detection configuration will be described.

{Overall Configuration} This image forming apparatus A is shown in FIG.
As shown in FIG. 3, a structure based on image information is irradiated from the optical system 1 to form an image of a developer (hereinafter referred to as “toner”) on the photosensitive drum that is an image carrier. Then, in synchronization with the formation of the toner image, the recording medium 2 is transferred from the cassette 3a to the pickup roller 3b and the registration roller pair 3c1, 3c2.
In the image forming portion which is conveyed by the conveying unit 3 including the above, and which is formed into a cartridge as the process cartridge B, the toner image formed on the photosensitive drum is applied with voltage to the transfer roller 4 serving as the transfer unit to thereby form the recording medium 2. And the recording medium 2 is conveyed to the fixing unit 5 by the intermediate discharge roller 3d and the guide plate 3e. The fixing means 5 comprises a driving roller 5a and a fixing roller 5c having a heater 5b built therein, and applies heat and pressure to the recording medium 2 passing therethrough to fix the transferred toner image. Then, the recording medium 2 is conveyed by the discharge roller pair 3f, and is discharged to the discharge portion 6 through the reverse transport path.

On the other hand, in the process cartridge B forming the image forming portion, as shown in FIGS. 1 and 2, the photosensitive drum 7 having a photosensitive layer is rotated, and the surface thereof is transferred to a charging roller 8 as a charging means. Is uniformly charged by the application of the voltage, and the optical image from the optical system 1 is exposed to the photosensitive drum 7 through the exposure unit 9 to form a latent image, and the latent image is developed by the developing means 10. There is. The developing means 10 feeds the toner in the toner reservoir with a toner feeding member 10a, rotates a developing sleeve 10c having a fixed magnet 10b built therein, and at the same time, a toner layer to which a triboelectric charge is applied by a developing blade 10d is applied to the developing sleeve 10c. By forming the toner on the surface and transferring the toner to the photosensitive drum 7 according to the latent image, a toner image is formed and visualized. Then, after a voltage having a polarity opposite to that of the toner image is applied to the transfer roller 4 to transfer the toner image onto the recording medium 2, the cleaning blade 11a scrapes off the toner remaining on the photosensitive drum 7, and the scooping sheet 11b scoops it. take,
The residual toner on the photosensitive drum 7 is removed by the cleaning means 11 which collects in the waste toner reservoir 11c. Each component such as the photosensitive drum 7 is housed in a housing 12 in which a first frame body 12a and a second frame body 12b are combined to form a cartridge, and a cartridge mounting means provided in a main body 13 of the apparatus. In contrast, it is detachably attached.

In the cartridge mounting means, when the opening / closing member 14 is opened around the shaft 14a, a cartridge mounting guide member (not shown) is mounted on the left and right inner side surfaces of the opening / closing member 14, and the left and right guide members are process cartridges. Guide portions for inserting B are provided facing each other. Insert the process cartridge B along this guide,
The process cartridge B is attached to the image forming apparatus A by closing the opening / closing member 14.

{Photosensitive Drum Life Detecting Structure} Next, the photosensitive drum 7 life detecting structure will be described. As shown in FIG. 3, the cartridge B is provided with a disc 15 rotatable about a shaft 15a. When the cartridge B is attached to the device body 13, the disc 15 is provided to the device body 13. It is configured to be pressed against the roller 16. The roller 16 is connected to a stepping motor 17 and is rotated by driving the motor 17. Further, the circular plate 15 is provided with an opening 15b at a predetermined position, a cartridge B is mounted on the apparatus main body 13 side, and a light emitting element 18a which irradiates the opening 15b with light when the opening 15b is rotated to a predetermined position, A photocoupler 18 including a light receiving element 18b that receives the reflected light is provided.

Now, in this embodiment, the life of the photosensitive drum 7 is detected by the rotation of the disk 15, and its control structure is shown in the block circuit of FIG. In the figure,
The DC power supply 19 generates a predetermined voltage and supplies the DC voltage to each unit. The DC controller 20 controls the driving of the entire apparatus, and includes a CPU 20a and a ROM 20 inside.
b, RAM 20c and clock circuit 20d for generating a clock
have. The DC controller 20 also controls a high-voltage power supply 21 that biases the charging roller 8 and the developing sleeve 10c, and also controls the drive of a main motor 22 that rotates the photosensitive drum 7.

The integrated time during which the main motor 22 is driven is counted in the DC controller 20, and when this time exceeds a certain time, the motor (or solenoid) 23 is driven to rotate the disk 15 slightly. Let As a result, when the image forming apparatus is driven and the main motor 22 is driven, the disk 15 gradually rotates depending on the driving time. And opening
When 15b is rotated to the specified position, it is rotated by the photo coupler 18
Detected and transmitted to the DC controller 20.

Therefore, when the drive time of the photosensitive drum 7 rotated by the main motor 22 has passed a certain time, the DC controller 20 detects this and the controller 20 gives a signal indicating that the photosensitive drum 7 has reached the end of its life. Output. As a result, it is possible to reliably determine the life of the photoconductor drum 7 without providing a special speed reduction mechanism as in the conventional case.

Further, the process cartridge B is installed in the apparatus main body 13
Even if the disk B is removed from the cartridge B, since the disk 15 is provided on the cartridge B, the usage state of the cartridge B can be grasped by the rotation amount of the disk 15.

[Second Embodiment] In the above-described first embodiment, an example in which only the life of the photosensitive drum 7 is detected has been shown, but in the case of the process cartridge B, the cartridge B is replaced when the toner is out of the toner reservoir. Must. Also, when the waste toner reservoir 11c of the cleaning means 11 is full of waste toner, it must be replaced.

Therefore, as a structure for detecting the life of the cartridge B, means for detecting the remaining amount of toner or the amount of waste toner is provided in addition to the detection of the life of the photosensitive drum 7, and the developing means is provided.
When the remaining amount of toner in 10 becomes less than a certain amount, or when the amount of waste toner in the cleaning unit 11 becomes more than a certain amount,
An example of detecting the life of the cartridge B is shown.

For example, as a structure for detecting the remaining amount of toner in the developing means 10, as shown in FIG.
An antenna wire 23, which is formed by stretching a conductive wire parallel to the developing sleeve 10c, is attached in the vicinity of, and the remaining amount of toner is detected by detecting the impedance change between the developing sleeve 10c and the antenna wire 23. Development sleeve
Since the toner layer formed on 10c is applied with a bias voltage in which an AC component is superimposed on a DC component is applied to the developing sleeve 10c so that the toner layer is developed at a position facing the photosensitive drum 7, the antenna wire 23 It becomes an electrode and a voltage is generated.
Since the electrostatic capacity of the voltage varies depending on the amount of toner interposed between the developing sleeve 10c and the antenna wire 23, the voltage changes depending on the amount of toner, as shown in FIG. The remaining toner amount is detected based on this voltage change.

A toner remaining amount detecting means having the above-mentioned structure,
The process cartridge is provided with both the life detecting means of the photosensitive drum 7 of the first embodiment described above, and when the remaining toner amount from each means becomes less than a certain amount or when the photosensitive drum 7 reaches the life, A signal indicating that B is at the end of its life may be output and a display prompting replacement of the process cartridge B may be displayed.

In place of the toner remaining amount detecting means in the developing means 10, a means for detecting that the waste toner removed by the cleaning means 11 is full in the waste toner reservoir 11c is provided, and the waste toner is removed. May be output when the process cartridge B has reached the end of its life, or when the photosensitive drum 7 has reached the end of its life. In this case, whether or not a certain amount of waste toner has been collected in the waste toner reservoir 11cd can be determined by the same configuration as the toner remaining amount detecting configuration using the antenna wire described above.

As the structure for detecting the toner amount, it is also possible to use, for example, a piezo type detection element, a system for detecting the presence or absence of toner by the intensity of light, in addition to the structure for providing the antenna wire. .

[Third Embodiment] In the first embodiment described above,
The disk 15 is used as a method for detecting the drive time of the photosensitive drum 7.
However, the driving time itself may be counted.

For example, as shown in the block diagram of FIG.
The photoconductor drum 7 is driven by the main motor 22, and a counter 20e is provided in the DC controller 20 that controls the drive of the main motor 22 so that the integrated drive time of the main motor 22 is counted and the count value is a constant value. When it exceeds the limit, a signal indicating that the photosensitive drum 7 has reached the end of its life is output.

When the process cartridge B is replaced, the counter 20 is reset by the reset switch 24.
Reset e. With such a configuration, it is not necessary to provide the disc 15 or the like, and thus there is an advantage that the configuration is simplified.

[Other Embodiments] In the above-described embodiment, the process cartridge B is mounted on the image forming apparatus A and the life of the photosensitive drum 7 is detected. The configuration is not limited to the cartridge system, that is, the image forming apparatus in which the photosensitive drum is directly attached to the apparatus body can be similarly applied.

Further, the process cartridge B according to the present invention described above is not limited to the case of forming a single color image as described above, but a plurality of developing means are provided and a plurality of color images (for example, 2).
It can also be suitably applied to a cartridge that forms a color image, a three-color image, a full-color image, or the like.

As the developing method, various known developing methods such as a two-component magnetic brush developing method, a cascade developing method, a touchdown developing method and a cloud developing method can be used.

As for the structure of the charging means, the so-called contact charging method was used in the above-mentioned first embodiment, but a tungsten wire which has been conventionally used as another structure is provided with metal shields such as aluminum around the three sides, It goes without saying that a configuration may be used in which positive or negative ions generated by applying a high voltage to the tungsten wire are moved to the surface of the photosensitive drum to uniformly charge the surface of the drum.

The charging means may be of a blade type (charging blade), a pad type, a block type, a rod type, a wire type or the like, other than the roller type.

Further, as a method for cleaning the toner remaining on the photosensitive drum, the cleaning means may be constituted by using a blade, a fur brush, a magnetic brush or the like.

The above-mentioned process cartridge is
For example, an electrophotographic photosensitive member as an image carrier and at least one process means are provided. Therefore, as the mode of the process cartridge, in addition to the embodiment described above, for example, the image carrier and the charging means are integrally made into a cartridge, which can be attached to and detached from the apparatus main body. The image carrier and the developing means are integrally formed into a cartridge, which can be attached to and detached from the main body of the apparatus. The image carrier and the cleaning means are integrally made into a cartridge so that it can be attached to and detached from the apparatus main body. Further, there is one in which an image carrier and two or more of the above-mentioned process means are combined into an integrated cartridge, which can be attached to and detached from the apparatus main body.

That is, the above-mentioned process cartridge is one in which the charging means, the developing means or the cleaning means and the electrophotographic photosensitive member are integrally made into a cartridge, and the cartridge can be attached to and detached from the main body of the image forming apparatus. . Further, at least one of the charging means, the developing means, and the cleaning means and the electrophotographic photosensitive member are integrally made into a cartridge so that it can be attached to and detached from the main body of the image forming apparatus. Further, it means that at least the developing means and the electrophotographic photosensitive member are integrally made into a cartridge so as to be attachable to and detachable from the apparatus main body.

Further, although the laser beam printer has been illustrated as the image forming apparatus in the above-mentioned embodiments, the present invention is not limited to this, and other image forming apparatus such as an electrophotographic copying machine, a facsimile machine or a word processor can be used. It is also possible to use for.

[0040]

As described above, according to the present invention, the life of the image bearing member is detected by detecting the driving time of the image bearing member.
It is possible to accurately determine the life. Further, since no special deceleration mechanism is required for detecting the drive time, no increase in cost will occur.

Further, by using it together with the toner amount detecting means, it becomes possible to make a more accurate cartridge life judgment.

[Brief description of drawings]

FIG. 1 is a configuration explanatory view of an image forming apparatus equipped with a process cartridge according to an exemplary embodiment of the present invention.

FIG. 2 is an explanatory diagram of a configuration of a process cartridge.

FIG. 3 is an explanatory diagram of a life detection configuration of a photosensitive drum.

FIG. 4 is a block diagram of a cartridge life detection configuration.

FIG. 5 is a graph showing a relationship between a toner amount and a voltage of an antenna wire.

FIG. 6 is another block explanatory diagram of the cartridge life detection configuration.

[Explanation of symbols]

A ... Image forming apparatus, B ... Process cartridge, 1 ... Optical system, 2 ... Recording medium, 3 ... Conveying means, 3a ... Cassette,
3b ... Pickup roller, 3c1, 3c2 ... Registration roller, 3d ... Intermediate transport roller, 3e ... Guide plate, 3f ... Ejection roller, 4 ... Transfer roller, 5 ... Fixing means, 5a ... Drive roller, 5b ... Heater, 5c ... Fixing Rollers, 6 ... Ejection section, 7 ... Photosensitive drum, 8 ... Charging roller, 9 ... Exposed section,
10 ... Developing means, 10a ... Toner feeding member, 10b ... Magnet, 10
c ... developing sleeve, 10d ... developing blade, 11 ... cleaning means, 11a ... cleaning blade, 11b ... squeegee sheet, 11c ... waste toner reservoir, 12 ... housing, 12a ...
1st frame, 12b ... 2nd frame, 13 ... Device body, 14 ... Opening / closing member, 14a ... Shaft, 15 ... Disc, 15a ... Shaft, 15b ... Opening, 16 ...
Roller, 17 ... Stepping motor, 18 ... Photo coupler,
18a ... Light emitting element, 18b ... Light receiving element, 19 ... DC power source, 20 ...
DC controller, 20a ... CPU, 20b ... ROM, 20c
... RAM, 20d ... Clock circuit, 20e ... Counter, 21 ...
High voltage power supply, 22 ... Main motor, 23 ... Antenna wire, 24 ... Reset switch

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroto Hasegawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kazuro Ono 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (72) Inventor Hiroaki Sakai, 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) In Minor, Minakuma, 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yasunari Obara 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (6)

[Claims] 1. An image forming apparatus for forming an image on a recording medium by rotating an image bearing member, an image bearing member, a developing unit for forming a toner image on the image bearing member, and a residual toner remaining on the image bearing member. Cleaning means for removing toner, image carrier drive time detecting means for detecting that the drive time of the image carrier exceeds a certain time, and image carrier when a signal from the image carrier drive time detecting means is inputted. An image forming apparatus comprising: a life detecting unit that outputs a life detecting signal for a body. 2. A removal toner amount detection unit for detecting that the amount of toner removed by the cleaning unit exceeds a certain amount, and the life detection unit is the removal toner amount detection unit or the image carrier driving unit. The image forming apparatus according to claim 1, wherein the image forming apparatus outputs a life detection signal of the image bearing member when a signal from the time detecting unit is input. 3. A remaining toner amount detecting means for detecting that the amount of toner remaining in the developing means is less than a certain amount, and the life detecting means is the remaining toner amount detecting means or the remaining toner amount detecting means. 2. The image forming apparatus according to claim 1, wherein when the signal from the image carrier driving time detecting means is inputted, a life detecting signal of the image carrier is outputted. 4. An image forming apparatus for mounting a process cartridge to form an image on a recording medium, wherein a process cartridge having an image carrier and at least one process unit acting on the image carrier is mounted. Mounting means, image carrier drive time detecting means for detecting that the drive time of the image carrier exceeds a certain time, and a cartridge exchange signal is output when a signal from the image carrier drive time detecting means is input. An image forming apparatus comprising: a life detecting unit. 5. A removed toner amount detecting means for detecting that the amount of toner removed by the cleaning means exceeds a certain amount, the cleaning means for removing the toner remaining on the image carrier is provided as the process means. The image forming apparatus according to claim 4, wherein the life detecting unit outputs a cartridge exchange signal when a signal from the removed toner amount detecting unit or the image carrier driving time detecting unit is input. 6. A residual toner amount detection for detecting that the amount of toner remaining on the developing unit is less than a certain amount, which has a developing unit for forming a toner image on the image carrier as the process unit. 5. The image according to claim 4, further comprising means, wherein the life detecting means outputs a cartridge exchange signal when a signal from the remaining toner amount detecting means or the image carrier driving time detecting means is input. Forming equipment.