JPH09237018A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exactly predict the service life of a photoreceptor on a photoreceptor drum in an electrophotographic image forming device such as laser beam printer. SOLUTION: When an electrifying roller 11 is arranged to be in contact with a photoreceptor 13 on the surface of a photoreceptor drum 10, and a bias voltage is applied to the roller 11 by a high-voltage power source, a current sensor 18 detects the current flowing through the photoreceptor drum 10. Consumption of the photoreceptor 13 is related to the value of this current. By comparing the integrated current value at the time of using the image forming device with the integrated current which corresponds to the service life of the photoreceptor 13, the service estimate of the photoreceptor 13 is conducted and the predicted value is displayed on a display panel.

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 having a life detecting means for detecting the life of an electrophotographic photosensitive member mounted on a copying machine, a laser beam printer or the like.

[0002]

2. Description of the Related Art FIG. 8 shows a schematic configuration of an electrophotographic laser beam printer as a conventional image forming apparatus.

Drum type electrophotographic photosensitive member (photosensitive drum)
31 is rotationally driven in the direction of arrow R31, and the surface thereof is uniformly charged by the charging member 32 of the charger. Here, when the environment in which the image forming apparatus is used has a low relative humidity such as low temperature and low humidity, in order to uniformly charge the surface of the photosensitive drum 31, a charging bias higher than usual is used. It is necessary to charge. Next, the laser light 33 performs image exposure to form an electrostatic latent image. The electrostatic latent image is developed (visualized) as a toner image with toner attached by the charger 34. On the other hand, the transfer material P such as paper is fed to the transfer portion in synchronization with the toner image on the photosensitive drum 31, and the toner image on the photosensitive drum 31 is transferred onto the transfer material P by the transfer discharger 35. Is transcribed to. The transfer material P after the transfer of the toner image is heated and pressed by the charger 37 to fix the toner image on the surface. On the other hand, the transfer residual toner remaining on the surface of the photosensitive drum 31 after the toner image transfer is removed by the cleaning member 36, and the photosensitive drum 31 is used for the next image formation.

The photosensitive member (photosensitive layer) formed on the surface of the above-mentioned photosensitive drum 31 is generally zinc oxide, selenium,
There are inorganic optical semiconductors such as cadmium sulfide and amorphous silicon, and organic optical semiconductors. These photoreceptors
For example, it is used in a state of being applied or vapor-deposited on the surface of a drum base made of aluminum formed in a drum shape. In addition,
In addition to the photosensitive drum 31, a photosensitive belt in which a photosensitive member is provided on the surface of the belt base is also known.

Since the photosensitive drum 31 described above gradually deteriorates in accordance with its usage time, it is necessary to replace it with a new photosensitive drum after a predetermined usage period.
The reason why the replacement is necessary is that when the transfer residual toner on the surface of the photosensitive drum 31 is removed by the cleaning blade 36, the photosensitive member is gradually scraped off together with the transfer residual toner.
This is because when the film thickness of the photoconductor becomes less than a predetermined value, charging failure, developing failure, transfer failure, etc. are caused. Therefore, in order to replace the photosensitive drum 31 at an appropriate time, the life detecting means detects the life.

As the life detecting means, there is known a method of judging the life of the photoconductor by detecting the film thickness of the photoconductor from the current value output when the photoconductor is charged by applying a charging bias to the charging member 32. (For example, Japanese Patent Application No. 6-020433)
Issue).

[0007]

However, according to the method of detecting the photoconductor film thickness from the above-mentioned current value, the detected current value is very small, and therefore it is actually applied due to a problem such as an electric circuit error. Had a problem with poor accuracy. For example, laser beam printer (Canon LB
± 50% of the actual life when applied to P-730)
There is a degree of error, and even if it can be used, it may be detected as a life due to an error, or conversely, it may be detected even if it has reached the end of its life.

Further, there is also known one which informs the user of the detected life of the photoconductor through a display device. However, in this case, since the display is made only when the photoconductor reaches the end of its life, the user may not be ready for a new photoconductor drum even when the life is displayed.In this case, It is very inconvenient because the image forming apparatus cannot be used until the preparation can be made, or an image defect occurs if the image forming apparatus is forcibly used. As a method to eliminate such inconvenience, the number of cleanings or the number of rotations of the photosensitive drum is counted from the time when the photosensitive drum is new so that the user can be informed of the replacement time (approaching the life) before the photosensitive body reaches the end of its life. And accumulate
It is possible to display the replacement time to the user when the predetermined number of times or the number of rotations is exceeded.

However, the film thickness of the photoconductor when it is new varies, and the amount of abrasion of the photoconductor during cleaning is
There are differences between the image forming apparatuses. Further, when the environmental conditions of use of the image forming apparatus are low humidity, the charging bias is increased, so that the damage on the surface of the photoconductor during charging is increased, and the amount of abrasion of the photoconductor during cleaning is increased. For these reasons, it has been conventionally considered difficult to detect the life of the photoconductor that is suitable for each usage state.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an image forming apparatus capable of detecting the life of the photoconductor in accordance with the individual use condition.

[0011]

According to a first aspect of the present invention, there is provided a charged member having a photosensitive member on its surface, a charging member disposed in contact with the photosensitive member, and a voltage for applying a voltage to the charging member. An image forming apparatus that includes an applying unit and that charges or discharges the photoconductor through the charging member, and detects a current that is output when the photoconductor is charged or discharged through the charging member. Means, first storing means for updating and storing the integrated value of the current detected by the current detecting means, and integrated value of the current updated and stored by the first storing means,
And a control unit for predicting the life of the photoconductor by comparing the integrated value of the current corresponding to the life of the photoconductor.

The present invention according to claim 2 is characterized in that the first storage means is provided integrally with the body to be charged.

The present invention according to claim 3 is characterized in that the member to be charged is unitized independently and the first storage means is provided in a part of the unit.

According to a fourth aspect of the present invention, the charged body and at least one process device are integrated into a cartridge container to form a process cartridge which is detachable from the image forming apparatus main body. The first
The storage means is incorporated in a part of the process cartridge.

According to a fifth aspect of the present invention, there is provided a member to be charged having a photosensitive member on its surface, a charging member arranged in contact with the photosensitive member, and voltage applying means for applying a voltage to the charging member. In an image forming apparatus that charges or removes electricity from the photoconductor through the charging member, an environment detection unit that detects an environmental condition, a count unit that detects the number of cleanings of the photoconductor, and a cleaning number that the count unit counts. Correcting means for correcting the above based on the output of the environment detecting means, a second storing means for updating and storing an integrated value of the cleaning number corrected by the correcting means, and a cleaning number updated and stored by the second storing means. And the integral value of
Control means for predicting the life of the photoconductor by comparing the integral value of the number of cleanings corresponding to the life of the photoconductor,
Is provided.

The present invention according to claim 6 is characterized in that the second storage means is provided integrally with the member to be charged.

The present invention according to claim 7 is characterized in that the member to be charged is unitized independently and the second storage means is provided in a part of the unit.

According to an eighth aspect of the present invention, the charged body and at least one process device are integrated into a cartridge container to form a process cartridge which is detachable from the main body of the image forming apparatus. The first
The storage means is incorporated in a part of the process cartridge.

The present invention according to claim 9 is characterized by comprising display means for displaying a life expectancy of the photoconductor by the control device.

The present invention according to claim 10 is characterized in that when the photoconductor approaches the end of its life, the life expectancy is displayed by the display means.

[Operation] Since the life of the photoconductor is predicted based on the integrated value of the current output when the photoconductor is charged (or discharged), the life is predicted based on the output current value itself. Unlike the case, it is possible to accurately detect that the photoconductor approaches the end of its life or reaches the end of its life.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. <Embodiment 1> First, referring to FIG. 1, an electrophotographic photosensitive member (hereinafter referred to as "photosensitive drum") as an image bearing member (charged member) mounted on an image forming apparatus 1 such as a laser beam printer. ) The film thickness measuring principle of the photoconductor 13 will be described.

The photosensitive drum 10 is constructed by providing a photosensitive member (photosensitive layer) 13 such as OPC (organic optical semiconductor) on the surface of a drum-shaped base 14 made of aluminum. Base 1
4 is grounded via a resistor 15 and connected to a current value sensor (current detecting means) 18 via an amplifier 17. A charging roller (charging member) 11 is placed in contact with the photoconductor 13 and a high voltage is applied by a high voltage power supply (voltage applying means) 12. As a result, a current flows through the photoconductor 13, the base 14, the resistor 15, and the ground 16. This current is amplified by the amplifier 17 and measured by the current value sensor 18.

For example, in a laser beam printer (LBP-730 manufactured by Canon Inc.), there is a relation between the current value measured by the above measuring method and the film thickness of the photoconductor, and the film thickness of the photoconductor can be known from the current value. You can Since the film thickness at the life of the photoconductor is known to be 8 μm by the experiment, if the photoconductor film thickness when not in use is known, the above measurement is performed and the current photoconductor film thickness can be obtained from the obtained current value. What percentage have you consumed so far?
You can find out what percentage remains.

Next, a method of determining the photoconductor film thickness when not in use and life expectancy will be described with reference to the flow charts of FIGS. 3 and 4. In the memory (first storage means) 24, the current value measured by the current value sensor 22 (the current value sensor is shown by 18 in FIG. 1) and the data of the photoconductor film thickness corresponding to the current value are measured. , Data of the photoconductor film thickness (hereinafter referred to as M1) measured at the previous power-on, the photoconductor film thickness when not in use (hereinafter referred to as M)
0) and the photoconductor film thickness at the end of its life (hereinafter referred to as M2) are written. When the power source of the image forming apparatus 1 is turned on, the CPU (control means) 21 has a current value sensor 22.
The current value is read by and the photoconductor film thickness (hereinafter referred to as M) corresponding to the current value is extracted from the memory 24 (S
1). Next, it is compared with the previously measured film thickness M1 stored in the memory 24 (S2). At this time, considering the error 1
Leave a margin of μm. If the photoconductor film thickness is thicker than the previous time, it is determined that the photoconductor drum 10 is new, and the initial value M0 is changed to the current measurement value M and rewritten in the memory 24 (S3). Next, the previously measured value M1 is replaced with the currently measured value M and rewritten in the memory 24 (S4). Memory 2
It is determined whether the photoconductor 13 has reached the end of life by comparing it with the life value M2 stored in No. 4 (S5). If the photoconductor 13 has reached the end of life, it is displayed on the display panel (display means) 26 that the photoconductor 13 has reached the end of life (S5).
6). If the service life is not reached, the remaining number up to the service life is calculated from the initial value M0 and the measured value M stored in the memory 24 and displayed on the display panel 26 (S7). The remaining number is calculated as follows.

{(M−M2) / (M0−M2)} × 100 (%) The life expectancy is calculated by the image forming user using the operation panel 2
It may be performed when 7 is operated, may be performed before image output, or may be displayed as a warning only when the remaining number is small as a result of life estimation.

Here, the feature of the present invention is to predict the life by detecting the current value and taking the cumulative value. There is a large error in predicting the life by measuring the current once. Therefore, the error between the expected life and the actual life is reduced by taking the cumulative value (integral value) of the current. <Second Embodiment> A second embodiment will be described with reference to FIGS.

Normally, in the image forming apparatus, when the relative humidity is lowered, the charging bias is set high in order to prevent the charging failure, so that the surface of the photoconductor 13 is greatly damaged by the discharge, and at the time of cleaning. The amount of scraping will increase.

FIG. 5 shows the photoconductor film thickness after 6000 image formation (printing) using the same laser beam printer (LBP-730 manufactured by Canon Inc.) used in the first embodiment while changing the relative humidity. Indicates the amount of decrease. Here, the amount of decrease in the photoconductor film thickness when the relative humidity is 50% (relative decrease rate)
Was set to 1. According to the figure, the amount of decrease in the photosensitive member film thickness when the relative humidity is 20% is 1.3 times as large as that when the relative humidity is 50%. In other words, one cleaning at a relative humidity of 20% requires a relative humidity of 50%.
This is equivalent to 1.3 times of cleaning at%. Therefore, each time the cleaning is performed by the cleaning blade, if the amount of decrease in the photosensitive member film thickness (hereinafter referred to as “relative decrease amount C”) corrected by the correction unit in the CPU 21 is counted, the environment (humidity is reduced). ), It is possible to predict the life expectancy.

Next, referring to FIGS. 6 and 7, the life expectancy of the photoconductor will be described.

In the memory 24 in the image forming apparatus 1 in FIG. 7, the data in FIG. 5 (data indicating the relationship between the relative humidity and the relative decrease rate) and the life of the photoconductor 13 at the relative humidity of 50% are stored in the memory 24. The number of cleanings (hereinafter "lifetime value F2")
And) are written. A memory (second storage means) 28 is also incorporated in the photoconductor 13 so that the number of times of cleaning up to now (hereinafter referred to as "cumulative number F") can be stored. Of course, the cumulative number F of unused photoconductors 13 becomes zero.

When the power of the image forming apparatus 1 is turned on, the CPU 21
Reads the current value measured by the current value sensor 22 and extracts the corresponding photoconductor film thickness, reads the relative humidity from the relative humidity sensor (environment detecting means) 23 (S11), and corresponds to the relative humidity from the memory 24. The reduction rate C is derived (S12). Next, the image forming apparatus 1
When the photoconductor 13 is cleaned (S13), the reduction rate C is added to the memory in the photoconductor 13 (S14). If the added total exceeds the life value F2 (S5), it is displayed on the display panel 26 that it is a life (S16).
If the life is not reached, the remaining number is calculated and displayed on the display panel 26 (S17). The remaining number is obtained as follows: {(F2-F) / F2} × 100 (%) Note that this life prediction may be performed when the user operates the operation panel 27, or the life prediction is performed. As a result, the warning may be displayed only when the remaining number is small.

Although the above description has been made by mounting the memory 28 in the photosensitive member 13, when the photosensitive drum 10 is configured as a photosensitive drum unit that can be easily replaced, a part of the unit other than the photosensitive drum is used. In addition, the photosensitive drum 10 and at least one other process device (for example,
In the case where a developing device and a cleaning device) are integrally incorporated in a cartridge container to form a process cartridge that is detachable from the main body of the image forming apparatus, the memory 28 is mounted on a part of the process cartridge. Good.

[0034]

As described above, according to the present invention,
Since the life of the photoconductor is predicted based on the integrated value of the current output when the photoconductor is charged (or discharged), unlike the case where the life is predicted based on the output current value itself, the photoconductor It is possible to accurately detect the life expectancy of (the photoconductor has approached its life or has reached its life). Further, when the result of life prediction is displayed on the display means, the user can prepare a new member to be charged in advance before the photoconductor reaches the end of its life according to this display.

Further, when the life of the photoconductor is predicted based on the integrated value of the number of cleanings, the cleaning frequency is further corrected by correcting the number of cleanings according to the environment such as humidity detected by the environment detecting means. It becomes possible to predict the service life.

[Brief description of drawings]

FIG. 1 is a diagram showing a method of detecting a photoconductor film thickness.

FIG. 2 is a diagram showing a correlation between a photoreceptor film thickness and a current value.

FIG. 3 is a block diagram showing a schematic configuration of the image forming apparatus according to the first embodiment.

FIG. 4 is a flowchart of a photosensitive member life prediction in the first embodiment.

FIG. 5 is a diagram showing a correlation between relative humidity and a relative reduction rate (of the photoconductor).

FIG. 6 is a flowchart of a photosensitive member life prediction in the second embodiment.

FIG. 7 is a block diagram showing a schematic configuration of an image forming apparatus according to a second embodiment.

FIG. 8 is a diagram showing a schematic configuration of an image forming apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Charged body (photosensitive drum) 11 Charging member (charging roller) 12 Voltage applying means (high voltage power source) 13 Photosensitive body (photosensitive layer) 14 Substrate 17 Amplifiers 18, 22 Current detecting means (current sensor) 21 Control Means (CPU, correction means) 23 Environment detection means (relative humidity detection sensor) 24 First storage means (memory) 26 Display means (display panel) 28 Second storage means (memory)

Claims (10)

[Claims] 1. An object to be charged having a photoconductor on its surface, a charging member arranged in contact with the photoconductor, and a voltage applying means for applying a voltage to the charging member, wherein the charging member is provided through the charging member. In an image forming apparatus for charging or discharging a photoconductor, a current detection unit for detecting a current output when the photoconductor is charged or discharged via the charging member, and an integral of a current detected by the current detection unit. A first storage unit for updating and storing a value; a current integral value updated and stored by the first storage unit is compared with an integral value of a current corresponding to the life of the photoconductor, and the life of the photoconductor is compared. An image forming apparatus, comprising: a control unit that predicts. 2. The image forming apparatus according to claim 1, wherein the first storage unit is provided integrally with the body to be charged. 3. The image forming apparatus according to claim 2, wherein the member to be charged is unitized independently and the first storage unit is provided in a part of the unit. 4. A process cartridge detachably attached to a main body of an image forming apparatus by integrally incorporating the member to be charged and at least one process device into a cartridge container, and further comprising the first storage means. The image forming apparatus according to claim 2, wherein the image forming apparatus is incorporated in a part of the process cartridge. 5. An object to be charged having a photoconductor on the surface thereof, a charging member arranged in contact with the photoconductor, and a voltage applying means for applying a voltage to the charging member, wherein the charging member is provided through the charging member. In an image forming apparatus for charging or discharging a photoconductor, an environment detection unit for detecting an environmental condition, a count unit for detecting the number of cleanings of the photoconductor, and an output of the environment detection unit for the number of cleanings counted by the counting unit. Correction means for making corrections based on the above, a second storage means for updating and storing the integrated value of the number of cleanings corrected by the correction means, an integrated value for the number of cleanings updated and stored by the second storage means, and the photosensitive material. And a control unit that predicts the life of the photoconductor by comparing the integral value of the number of cleanings corresponding to the life of the body. Place. 6. The image forming apparatus according to claim 5, wherein the second storage unit is provided integrally with the charged body. 7. The image forming apparatus according to claim 6, wherein the member to be charged is made into a single unit, and the second storage unit is provided in a part of the unit. 8. A process cartridge detachably attached to an image forming apparatus main body by integrally incorporating the member to be charged and at least one process device into a cartridge container, and further comprising the first storage means. The image forming apparatus according to claim 6, wherein the image forming apparatus is incorporated in a part of the process cartridge. 9. The image forming apparatus according to claim 1, further comprising display means for displaying a life expectancy of the photoconductor by the control device. 10. When the photoconductor approaches the end of its life,
The image forming apparatus according to claim 9, wherein the display unit displays a life prediction.