JP3179735B2 - Image carrier life detecting method, image forming apparatus, and process cartridge - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting the life of an image carrier used in an electrophotographic image forming apparatus, an image forming apparatus using the life method for an image carrier, a process cartridge used in the image forming apparatus, and The present invention relates to an electrophotographic image forming apparatus to which a process cartridge can be attached and detached.

Here, as an electrophotographic image forming apparatus, for example, an electrophotographic copying machine, an electrophotographic printer (for example, L
ED printers, laser beam printers, etc.), electrophotographic facsimile machines, and electrophotographic word processors.

A process cartridge is one in which charging means, developing means or cleaning means and an electrophotographic photosensitive member are integrally formed into a cartridge, and this cartridge is made detachable from an electrophotographic image forming apparatus main body. Alternatively, at least one of a charging unit, a developing unit, and a cleaning unit and an electrophotographic photosensitive member are integrally formed into a cartridge so as to be detachable from an electrophotographic image forming apparatus main body. This means that the body is integrally formed into a cartridge so as to be detachable from the main body of the electrophotographic image forming apparatus.

[0004]

2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus,
The following methods have been used to detect the life of an image carrier, that is, an electrophotographic photosensitive member (generally, a photosensitive drum is often used).

Conventional example 1: Method of integrating the number of prints (copies) Although this method is the simplest method, even if the print (copy) sizes are different, for example,
In the case of A4 size and A3 size, there is a disadvantage that the accuracy of life detection is not good because the same sheet is counted. Further, the accuracy of life detection is not good because the drum rotation time per sheet varies depending on how many sheets are printed per job.

Conventional Example 2: Method of Detecting Charge Amount by Surface Potential Sensor This method is disclosed in the prior art of Japanese Patent Application Laid-Open No. 4-51259. Actually, a decrease in the charging potential of the photosensitive drum or a decrease in the latent image contrast can be directly detected by the surface potential sensor, so that the life can be detected more accurately by reflecting the state of the output image as compared with the first conventional example.

[0007] However, a surface potential sensor and an electric circuit for processing the output of the sensor are required, which increases the cost. Further, in the longitudinal direction, only information on the drum corresponding to the sensor position can be judged, so that it is vulnerable to partial failure, and it is not always accurate in consideration of instability such as sensor variation and aging. This is not a life detection method.

As a method for solving the problem of the above-mentioned prior art example 1 and increasing the detection accuracy, there is the following method.

Japanese Patent Application Laid-Open No. 5-188677 discloses a method of integrating the number of rotations of a photosensitive drum instead of integrating the number of prints (copies). There is also a method of integrating the rotation time of the photosensitive drum with the same contents. In both cases, as compared with the case of accumulating the number of prints, the number of rotations increases when the paper size is large, and the number of rotations decreases when the paper size is small. An error in life detection due to a difference in size is reduced. Also, since the number of rotations (rotation time) of the drum is directly integrated regardless of the number of prints per job, there is an advantage that the accuracy of life detection is good.

[0010] There is also a method that further develops this method.
That is, in Japanese Patent Application Laid-Open No. 4-98265, the drum rotation speed during actual image formation is integrated by integrating the drum rotation speed only when the transfer charger is operated. It is disclosed that more accurate life detection is possible.

According to Japanese Patent Application Laid-Open No. Hei 6-180518, the number of rotations of the drum while charging is performed and the number of rotations of the drum while the cleaning member is in contact are integrated, and the respective settings are made. It is disclosed that the life (judgment) is determined based on the value (life).

On the other hand, there is the following method for notifying the user in advance of the replacement timing of the process cartridge.

According to JP-A-5-333626,
First, a process cartridge includes a cleaner and an image carrier, and a storage element is provided in the process cartridge. In addition, the replacement display operation based on the life of the image carrier is
When the number of prints has been counted and the guaranteed life of the image carrier has expired, the device is stopped in order to make it unusable, indicating that it is time to replace it before the guaranteed life. Is displayed, and a message that prompts the user to approach the time to stop the apparatus when the apparatus is used further is displayed.

In the replacement display operation based on the capacity in the toner storage unit, the on-time of the drive motor for toner replenishment is integrated, and the integrated time is assumed to be the earliest under the worst conditions in consideration of various variations. Stop the device. In this case as well, a display prompting replacement with a certain value of the integrated time until the device is stopped, and a display prompting that the time to stop the device with a further advanced integrated time is approaching.
In addition, the operation based on the life of the image carrier and the operation based on the capacity of the toner storage section are usually set so that the number of prints is prioritized. The latter operation is intended to be performed when the image carrier is likely to become full earlier than the guaranteed number of images.

In addition, when the process cartridge is replaced, the total energizing time of the primary charger of the image forming apparatus is written into the storage element by the CPU provided in the image forming apparatus, and the total time of the subsequent primary charger is written. Is written and stored, and the storage element of the used process cartridge is collected and analyzed, whereby the rotation speed of the image carrier (photosensitive drum) of the image forming apparatus using the used process cartridge at the present time It is described that the total amount such as the discharge time of the image forming apparatus and the corotron can be accurately grasped, and information can be collected for the image forming apparatus at intervals of the process cartridge replacement.

More specifically, the number of operation cycles of the image carrier of the image forming apparatus when the process cartridge is replaced, the replacement time of the ozone filter, the wear data prediction of the image carrier, and the like can be grasped. However, since the life determination of the image carrier in this publication is based solely on the number of prints, the accuracy of the life prediction is not good as described above.

[0017]

In recent years, as a primary charging device, a contact charging device has been widely used in place of a conventionally used corona charging device. The contact charging device has a great advantage in that it requires a lower applied bias than the conventional corona charging device, generates very little ozone, requires fewer components constituting the charging device, and can be provided at low cost. .

The contact charging device is roughly classified into a brush charging device and a roller charging device depending on the shape of the member used. The brush charging device has problems such as brushes of the brush and fall of the hair when the brush is in contact with the photoconductor for a long time.

On the other hand, in the roller charging device, it is necessary to adjust the resistance of the roller in order to obtain uniform charging, it is necessary to prevent the drum from being contaminated by bleed from rubber constituting the roller, There are difficult problems such as strict restrictions on the shape, surface properties, etc. of the roller to obtain.

The voltage applied to the charging member is such that only a DC bias is applied (hereinafter referred to as DC charging).
AC bias superimposed on DC bias (hereinafter referred to as A
C charge). Generally, AC charging has a feature that uniform charging is possible as compared with DC charging.

Further, in the AC charging, a roller is used as a charging member, and the applied bias is adjusted to an AC voltage of twice or more the discharge starting voltage.
A device in which a DC voltage is superimposed on a voltage (JP-A-63-1496)
No. 69, Japanese Patent Application Laid-Open No. 1-267667), a device in which a conductive brush is used as a charging member and a DC voltage is superimposed on an AC voltage having an applied bias of twice or less the discharge starting voltage (Japanese Patent Application Laid-Open No. 6-130732) Etc.

Advantages of contact charging include a small amount of ozone generated and a small number of components constituting a charging device.
Although it has already been described that the photosensitive drum can be provided at a low cost, the damage to the photosensitive drum is larger than that of the corona charging.
The tendency is remarkable in the PC drum.

Even with the same contact charging method, the damage to the photosensitive drum depends on the applied voltage, and the greater the applied voltage, the greater the damage. Even when only a DC voltage is applied, the OPC drum is rotated without applying a bias. It was found that when the AC voltage was applied, the damage (particularly, the amount of scraping of the OPC drum) was several times larger than when only the DC voltage was applied.

This phenomenon is particularly remarkable when an AC voltage that is twice or more the discharge starting voltage is applied. However, even when the AC voltage is twice or less the discharge starting voltage, it is still several times as large as the DC voltage alone. There is damage.

Also, when the frequency of the AC voltage is increased, the damage of the OPC drum tends to increase.

Further, when the operating speed (the rotation speed of the OPC) is changed, the damage to the OPC drum changes depending on the charging condition at that time.

Therefore, the life of the photosensitive drum is detected in an image forming apparatus using contact charging with a plurality of operating speeds and a plurality of charging conditions during image formation, using both an AC voltage and a DC voltage as charging means. In such a case, it is difficult to accurately predict the life of the photosensitive drum using the conventional method of detecting the life of the drum using the rotational speed of the drum. There is a possibility that an inconvenience of issuing a warning when no is coming may occur.

Accordingly, a main object of the present invention is to provide a method of detecting the life of an image carrier for accurately detecting the life of the image carrier.
An object of the present invention is to provide an image forming apparatus using the detection method, a process cartridge mounted on the image forming apparatus, and an image forming apparatus including the process cartridge.

Another object of the present invention is to provide an image carrier life detecting method for accurately detecting that the replacement time due to the life of the image carrier is near, an image forming apparatus using the detecting method, and the image forming apparatus. And an image forming apparatus provided with the process cartridge.

[0030]

The above object is achieved by a method for detecting the life of an image carrier according to the present invention, an image forming apparatus and a process cartridge using the method, and an image forming apparatus provided with the process cartridge. . In summary, the present invention relates to a method for detecting the life of an image carrier in an image forming apparatus having at least an image carrier and a charging unit to which a voltage is applied and comes into contact with the image carrier, wherein the applied voltage is a DC bias component. It includes an AC bias component and has m kinds (m ≧ 2) of operation speeds Vm and n kinds (n ≧ 1) of bias application conditions during the image forming operation, and applies the bias under the operation speed Vm. Time tm during which a bias is applied to the charging means based on condition n
n, and using the detected time tmn and a predetermined coefficient kmn, the damage index D of the image carrier is calculated as follows: D = k11 × t11 + k21 × t21 +... + kmn
× tmn (where k11> 0, k21... Kmn ≧ 0), and the obtained damage index D is integrated.
The life of the image carrier is determined by comparing the integrated value S and life information R which is a predetermined life of the image carrier. is there.

According to another aspect of the present invention, there is provided a method for detecting the life of an image carrier in an image forming apparatus having at least an image carrier and a charging unit to which a voltage is applied and comes into contact with the image carrier. Includes a DC bias component and an AC bias component, and includes m (m ≧ 2) operation speeds Vm and n (n ≧ n) operation speeds during the image forming operation.
1) detecting the time tmn during which the bias is applied to the charging means based on the bias application condition n under the operation speed Vm and the detected time t
.. Tmn, and using the accumulated time integrated values S11, S21... Smn, the damage index D of the image carrier is calculated as follows: D = k11 × S11 + k21 × S21 +.
× Smn (where k11> 0, k21... Kmn ≧ 0), and the calculated damage index D of the image carrier and a predetermined lifetime are defined as the lifetime of the image carrier. The life of the image carrier is determined by comparing information R with the life of the image carrier.

According to another aspect of the present invention, in an image forming apparatus having at least an image carrier and a charging unit applied with a voltage and in contact with the image carrier, the applied voltage includes a DC bias component and It includes an AC bias component and has m kinds (m ≧ 2) of operation speeds Vm and n kinds (n ≧ 1) of bias application conditions during the image forming operation. A detection means for detecting a time tmn during which a bias is applied to the charging means based on the detection time, and a damage index D of the image carrier using the time detected by the detection means and a predetermined coefficient kmn. t11 + k21 × t21 + ... + kmn
× tmn (where k11> 0, k21... Kmn ≧ 0), and a damage index D of the image carrier.
Means for integrating the integrated value into the integrated value S, means for comparing the integrated value S integrated by the integrating means with a predetermined lifetime information R as the life of the image carrier, and a comparison between the comparing means. Warning means or notification for warning or displaying the life of the image carrier when the integrated value of the image carrier damage integrated by the integration means based on the result is equal to or longer than a predetermined integration time as the life of the image carrier. And an image forming apparatus.

Further, according to another aspect of the present invention,
In an image forming apparatus having at least an image carrier and a charging unit to which a voltage is applied and which is in contact with the image carrier, the applied voltage includes a DC bias component and an AC bias component, and during image forming operation, the number of types of the applied voltage is m. It has (m ≧ 2) operation speed Vm and n kinds of (n ≧ 1) bias application conditions, and detects a time tmn during which a bias is applied to the charging unit based on the bias application condition n under the operation speed Vm. .. + Kmn, using a detection unit that performs the detection, and the time detected by the detection unit and a predetermined coefficient kmn, to calculate the damage index D of the image carrier. D = k11 × t11 + k21 × t21 +.
× tmn (where k11> 0, k21... Kmn ≧ 0), and a damage index D of the image carrier.
Integrating means for integrating the image bearing member, and life information R indicating the life of the image bearing member and a predetermined value of the integrated value S, or replacing the image bearing member before the image bearing member reaches the end of its life. And comparing means for comparing the warning information Y smaller than at least one or more pieces of predetermined life information R in order to prompt the preparation. The comparing means accumulates based on the comparison result of the comparing means. When the integrated value S is equal to or more than the predetermined warning information Y, a warning or display is provided for the preparation for replacing the image carrier, and based on the result of the comparing means, the integrated value S integrated by the integrating means is determined in advance. An image forming apparatus is provided which warns or displays the life of the image carrier when the life information is equal to or longer than the predetermined life information R and stops the image forming operation of the main body.

According to another aspect of the present invention, there is provided an image forming apparatus in which a process cartridge including at least an image carrier is detachably mountable to an apparatus main body, and has a charging means to which a voltage is applied and which comes into contact with the image carrier. , The process cartridge includes a storage element, the voltage applied to the charging unit includes a DC bias component and an AC bias component, and m (m ≧ 2) operation speeds Vm and n during an image forming operation. Detecting means for detecting a time tmn during which a bias is applied to the charging means based on the bias applying condition n under the operating speed Vm and having a bias application condition of a kind (n ≧ 1); Using the time and a predetermined coefficient kmn, the damage index D of the image carrier is calculated as follows: D = k11 × t11 + k21 × t21 +... + Kmn
× tmn (where k11> 0, k21... Kmn ≧ 0), and a damage index D of the image carrier.
An image forming apparatus comprising: an integrating means for integrating the integrated value S into an integrated value S; and a means for writing the integrated value S to the storage element and reading the content.

Further, according to another aspect of the present invention,
In an image forming apparatus in which a process cartridge including at least an image carrier is detachably mountable to an apparatus main body and has a charging unit to which a voltage is applied and comes into contact with the image carrier, the process cartridge includes at least information on the life of the image carrier. A storage element for storing R; a voltage applied to the charging unit includes a DC bias component and an AC bias component; and m types (m ≧ 2) during an image forming operation
And the time tmn during which the bias is applied to the charging means based on the bias application condition n under the operation speed Vm.
, And the damage index D of the image carrier is calculated using the time detected by the detection means and a predetermined coefficient kmn. D = k11 × t11 + k21 × t21 +... + Kmn
× tmn (where k11> 0, k21... Kmn ≧ 0), and a damage index D of the image carrier.
Integrating means, and the integrated value S by the integrating means
And a means for reading the integrated value S and the information R on the life span of the image forming apparatus.

When calculating the damage index D of the image carrier by the calculating means, it is preferable to change the values of the coefficients k21... Kmn according to the ratio of the times t11, t21.

According to another aspect of the present invention, in an image forming apparatus having at least an image carrier and a charging unit applied with a voltage and in contact with the image carrier, the applied voltage includes a DC bias component and an AC bias component. Components, and has m kinds (m ≧ 2) of operation speeds Vm and n kinds (n ≧ 1) of bias application conditions during the image forming operation;
Detecting means for detecting a time tmn during which a bias is applied to the charging means under an operating speed Vm based on a bias applying condition n; time t11 detected by the detecting means;
Using the integrating means for integrating t21... tmn, the integrated values S11, S21... Smn and predetermined coefficients k11, k21. = K11 × S11 + k21 × S21 +... + Kmn
× Smn (where k11> 0, k21... Kmn ≧ 0), and a damage index D of the image carrier.
And a life information R which is a predetermined life of the image carrier, and a damage index D based on the comparison result of the comparison means is calculated as a predetermined life of the image carrier. An image forming apparatus is provided that has a warning unit or a notification unit that warns or displays the life of the image carrier when the time is longer than a predetermined time.

In an image forming apparatus having at least an image carrier and a charging means to which a voltage is applied and which comes into contact with the image carrier, the applied voltage is a DC bias component and A
Including a C bias component and during the image forming operation,
m kinds (m ≧ 2) of operating speeds Vm and n kinds (n ≧ 1)
Detecting means for detecting a time tmn during which a bias is applied to the charging means based on the bias applying condition n under the operating speed Vm, and times t11, t21,... Detected by the detecting means. integrating means for integrating tmn, and integrated time integrated values S11, S21,.
Smn and predetermined coefficients k11, k21 ...
Using kmn, the damage index D of the image carrier is calculated as follows: D = k11 × S11 + k21 × S21 +... + kmn
× Smn (where k11> 0, k21... Kmn ≧ 0), and a damage index D of the image carrier.
Life information R, which is the life of the image carrier, determined in advance,
Or comparing means for comparing warning information Y smaller than at least one or more predetermined life information R in order to prompt preparation for replacement of the image carrier before the life of the image carrier has expired; When the damage index D is equal to or more than the predetermined warning information Y based on the comparison result of the comparing means, a warning or display is provided for the preparation for replacing the image carrier, and based on the result of the comparing means, the damage index D is determined in advance. An image forming apparatus is provided which warns or displays the life of an image carrier that is equal to or longer than predetermined life information R and stops the image forming operation of the main body.

Further, according to another aspect of the present invention,
In an image forming apparatus in which a process cartridge including at least an image carrier is detachably mountable to an apparatus main body and has a charging unit to which a voltage is applied and which is in contact with the image carrier, the process cartridge includes a storage element, and the process cartridge includes a storage element. Applied voltage includes a DC bias component and an AC bias component, and m types (m ≧ 2) during the image forming operation.
And the time tmn during which the bias is applied to the charging means based on the bias application condition n under the operation speed Vm.
Detecting means for detecting the times t11 and t12
.., Tmn, and means for writing the obtained time integrated values S11, S21,... Smn to the storage element and reading out the contents. You.

Further, in an image forming apparatus in which a process cartridge including at least an image carrier is detachably attached to the apparatus main body and has a charging unit to which a voltage is applied and comes into contact with the image carrier, the process cartridge includes at least an image carrier. And a storage element for storing information R relating to the life of the device.
Including a C bias component and during the image forming operation,
m kinds (m ≧ 2) of operating speeds Vm and n kinds (n ≧ 1)
, And a detecting means for detecting a time tmn during which a bias is applied to the charging means based on the bias applying condition n under the operating speed Vm, and integrating the detected times t11, t12,... Tmn. Means for calculating
The obtained time integrated values S11, S21... Smn are written in the storage element, and the time integrated values S11, S2
1. An image forming apparatus comprising: means for reading information R relating to Smn and life.

When calculating the damage index D of the image carrier by the calculating means, the time integrated values S11, S21,.
It is preferable to change the values of the coefficients k21.

According to another aspect of the present invention, in a process cartridge including at least the image carrier, which is detachably attached to an image forming apparatus main body having a charging unit in contact with the image carrier when a voltage is applied, the storage element is provided. The voltage applied to the charging means includes a DC bias component and an AC bias component, and during the image forming operation, m kinds (m ≧ 2) of operating speeds Vm and n kinds (n ≧ 1) of biases The image forming apparatus main body includes a detecting unit that detects a time tmn during which a bias is applied to the charging unit based on a bias applying condition n under an operating speed Vm, and a time detected by the detecting unit. .. + Kmn using a predetermined coefficient kmn as follows: D = k11 × t11 + k21 × t21 +.
× tmn (where k11> 0, k21... Kmn ≧ 0), and a damage index D of the image carrier.
And a means for writing the integrated value S to the storage element and reading the content.

According to another aspect of the present invention, there is provided a process cartridge including at least the image carrier detachably mountable to a main body of an image forming apparatus having a charging means applied with a voltage and contacting the image carrier. A storage element for storing information R relating to the life of the carrier; a voltage applied to the charging means includes a DC bias component and an AC bias component; and m types (m ≧ 2) of operation speeds during image forming operation Vm and n types (n ≧ 1) of bias application conditions, and the image forming apparatus main body detects the time tmn during which the bias is applied to the charging unit based on the bias application condition n under the operation speed Vm. Using the time detected by the detecting means and a predetermined coefficient kmn, the damage index D of the image carrier is calculated as follows: D = k11 × t11 + k 1 × t21 + ··· + kmn
× tmn (where k11> 0, k21... Kmn ≧ 0), and a damage index D of the image carrier.
And a means for writing the obtained integrated value S into the storage element and reading the integrated value S and the information R on the service life.

Further, according to another aspect of the present invention,
In a process cartridge including at least an image carrier that is detachable from an image forming apparatus having a charging unit that is applied with a voltage and is in contact with the image carrier, the process cartridge includes a storage element, and a voltage applied to the charging unit is DC.
M (m ≧ 2) operating speeds Vm including a bias component and an AC bias component, and during an image forming operation;
The image forming apparatus has n kinds of (n ≧ 1) bias application conditions, and the image forming apparatus main body has a bias application condition n at an operation speed Vm.
Tm during which bias is applied to the charging means based on
detecting means for detecting n, and the detected times t11 and t1
.. Tmn, and means for writing the obtained time integrated values S11, S21... Smn to the storage element and reading the contents. You.

According to another aspect of the present invention, there is provided a process cartridge including at least the image carrier detachably mountable to an image forming apparatus main body having a charging means applied with a voltage and contacting the image carrier. A storage element for storing information R relating to the life of the carrier; a voltage applied to the charging means includes a DC bias component and an AC bias component; and m types (m ≧ 2) of operation speeds during image forming operation Vm and n types (n ≧ 1) of bias application conditions, and the image forming apparatus main body detects the time tmn during which the bias is applied to the charging unit under the operation speed Vm based on the bias application condition n. Detecting means, integrating means for integrating the detected times t11, t12... Tmn, and the obtained time integrated values S11, S21
... Smn are written in the storage element, and the integrated values S11, S21.
And a means for reading out the process cartridge.

[0046]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for detecting the life of an image carrier, an image forming apparatus, and a process cartridge according to the present invention will be described in more detail with reference to the drawings.

Embodiment 1 Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 shows a printer (LBP) that performs exposure using laser light, which is an image forming apparatus of the present embodiment. The printer according to the present embodiment is configured to be able to perform a printing operation by switching between an image resolution of 600 dpi and 1200 dpi in order to respond to a user's request.
The printer according to the present embodiment includes a process cartridge shown in FIG. 2 in which process means of an electrophotographic photosensitive member 1, which is a photosensitive drum (image carrier), a charging roller 2, a developing device 7, and a cleaning device 14, are incorporated. 17, a transfer roller 13, a fixing device 15, a laser scanner 4 as an optical system, a mirror 6, and the like are provided. The process cartridge 17 is attached to the main assembly of the apparatus.
It is mounted so that it can be replaced freely.

The image forming process of this printer will be described below.

The photoreceptor 1 has an outer diameter of 30 mm, is formed by laminating a photoconductive photosensitive layer 1a on the surface of a conductive substrate 1b made of aluminum, and is 600 dpi in the direction of arrow A in the figure.
Sometimes Vps1 = 100 mm / sec, 1200 dpi
Sometimes Vps2 = 50 mm / sec peripheral speed (operating speed)
Is driven to rotate.

The photoreceptor 1 receives a uniform negative charge by a charging roller 2 serving as a charging means, and then outputs the image information sent from a video controller (not shown) output from a laser scanner 4. Scanning exposure is performed by laser exposure 5 corresponding to the series electric digital image signal, and an electrostatic latent image is formed on the surface via a mirror 6 installed in the image forming apparatus main body.

The electrostatic latent image on the photoreceptor 1 is reversely developed by the toner 8 carried on the developing sleeve 11 in the developing device 7, and is visualized as a toner image.

The toner image is transferred onto the transfer paper P by the transfer roller 13. Then, the transfer paper P to which the toner image has been transferred is separated from the photoreceptor 1 and introduced into the fixing device 15 via the conveying unit 70, where the toner image is fixed, and then discharged from the image forming apparatus main body. Is done. After the transfer process, the photoconductor 1 removes residual toner from the cleaning device 1.
The cleaning is performed at 4 and the charging process is performed again.

The developing device 7 employs a non-contact developing method, and holds a developing sleeve 11 which is a rotatably supported toner carrier which carries the toner 8 and conveys it to the photosensitive member 1. A magnetic field generating means 10 fixed in the developing sleeve 11, a blade 9 for regulating the thickness of the toner layer on the developing sleeve 11, and a toner storage chamber 3.

The developing sleeve 11 has an AC bias and D
It is connected to a power supply 16 to which a C bias can be applied.
When a DC component of 0 V is supplied, the toner 8 applied in a thin layer on the developing sleeve 11 is developed on the photoconductor 1 at a portion facing the photoconductor 1.

In this embodiment, the toner 8 uses a magnetic one-component toner and is stored in the toner storage chamber 3.

The charging roller 2 has a two-layer structure in which a sponge layer 2b and a surface layer 2c are wound around a cored bar 2a. The cored bar 2a has a diameter of 6 mm, the outer diameter of the roller is 12 mm, and the roller length is about 220 mm. Also, the core metal 2a
Are pressurized by 500 gf in the direction of arrow c in the drawing, and are in contact with the photoreceptor 1 with a nip of about 1.5 mm.

The charging roller 2 is not driven and is driven to rotate relative to the photosensitive member 1.

The charging roller 2 is connected to a primary bias application power supply 12 via a cored bar 2a. In this embodiment, during a 600 dpi printing operation (photoconductor rotation speed Vps1), an image is set as bias application condition 1 AC bias (peak-to-peak voltage 1600)
V, frequency 1000 Hz, sine wave)
A bias voltage of 00V is applied to uniformly charge the surface of the photoconductor 1 to about -680V. In other parts during rotation of the photoconductor, the bias application condition 2 is set to -1250
There are a portion where only V is applied and the surface of the photoconductor 1 is charged to about -680 V, and a portion where no bias is applied as the bias application condition 3 (see FIG. 3).

During the 1200 dpi printing operation (photosensitive member rotation speed Vps2), DC bias -700V is superimposed on AC bias (peak-to-peak voltage 1600V, frequency 700Hz, sine wave) in a part including the image forming area as bias application condition 4. The applied bias is applied to uniformly charge the surface of the photoconductor 1 to about -680V. As in the 600 dpi print operation, in the other portions during rotation of the photoconductor, only -1250 V is applied as the bias application condition 2 to charge the surface of the photoconductor 1 to about -680 V. There is a portion to which no voltage is applied.

Here, in this embodiment, the bias application conditions are bias application conditions 1 and 4, and an AC bias is used to obtain a uniform good image in the image area and to eliminate the surface potential at the end of printing. Bias application condition 2; a uniform surface potential is not particularly required, but a constant surface potential is required for preventing unnecessary development of toner from a developing unit, cleaning a transfer member, and the like, and there is little damage to the photosensitive drum. It is switched for the purpose of using only DC bias, bias application condition 3; in particular, no bias is applied because a constant surface potential is not required.

The applied bias frequency under the bias application conditions 1 and 4 is set as follows: the moire image (the spatial frequency of the horizontal line image determined by the laser scanning frequency and the rotation speed of the photosensitive drum, the charging uneven frequency = the applied bias frequency) Is set to a frequency that does not cause interference fringes caused by approaching.

For the same purpose as the bias application condition 2,
There are also methods of lowering the voltage value (or current value) of the AC bias, lowering the frequency, and the like, and are similarly effective.

Next, a method of detecting the life of the electrophotographic photosensitive member, which is a characteristic part of the present invention, will be described with reference to the flowchart of FIG.

In FIG. 1, the photosensitive member 1 is rotated (rotational speed, rotation ON / OFF) by the photosensitive member rotation instructing section 22.
In the charging roller 2 serving as a contact charging unit, an AC bias and a DC bias are independently controlled by a primary AC voltage output instruction unit 21 and a primary DC voltage output instruction unit 20 as appropriate from a primary bias application power supply 12. And applied. The primary AC voltage output instructing unit 21, the primary DC voltage output instructing unit 20, and the photoconductor rotation instructing unit 22 are connected to a bias application time detecting unit 23, and during a 600 dpi print operation (rotation speed Vps1), one print operation is performed. Application time tmn = t11, t
12, t13 are detected.

The application time tmn is a combination of the type m (m ≧ 2) of the rotation speed of the photoconductor and the type n (n ≧ 1) of the above-described bias application condition, and t11 is the type of the photoconductor. Indicates that the rotation speed is 1 at Vps1 and the bias application condition is 1 described above. Similarly to t12, the bias application condition is 2 at the same rotation speed as t11, and t13 is Similarly, it shows that the bias application condition is 3 at the same rotation speed.

As shown in the printing operation sequence of FIG. 3, t11 is the application time information tac (= t11 = tac1 + tac) from the primary AC voltage output instructing section 21.
2), t12 is a time T in which the primary AC voltage is superimposed based on the application time information tdc from the primary DC voltage output instructing section 20.
The value after subtracting acdc (t12 = tdc-tacd)
c) and t13 are obtained by subtracting t11 and t12 from the photoconductor rotation time information tdr from the photoconductor rotation instruction unit 22 (t1).
3 = tdr− (t11 + t12)).

During a 1200 dpi print operation (rotational speed Vps2), application times t22, t23 and t24 of each bias application condition in one job of the print operation are detected (step 1). The application times t22 and t22
About the meaning of 23 and t24, t11, t12,
The description is omitted because it conforms to t13.

After one job of the printing operation is completed, the application time t11, t12, t13, t2 of each bias application condition
2, t23 and t24 are transferred to the photoconductor damage calculating unit 24, and the photoconductor damage index D is calculated by the following equation (step 2).

D = k11 × t11 + k12 × t12 + k13 × t13 + k22 × t22 + k23 × t23 + k24 × t24 (In the above formula, each coefficient is k11 = 1, k12 = 0.3,
k13 = 0.1, k22 = 0.15, k23 = 0.0
(5, k24 = 0.65) Next, the photoconductor damage integration storage unit 25 adds the photoconductor damage index D for one job to the stored photoconductor damage integration value S, and calculates the photoconductor damage integration value S. Update (step 3).

These operations are repeated for each print job. When one job is completed and the update of the integrated value S stored in the photoconductor damage integration storage unit 25 is completed, the comparison unit 26 reads the preset life information R from the photoconductor life information storage unit 27, and The magnitude relationship with the updated photosensitive member damage integrated value S is compared (step 4). As a result, when the updated integrated value S is larger than the life information R, a signal is sent to the warning unit (display unit) 28,
It warns or displays that the service life is reached, and prohibits printing of the main body (step 5). On the other hand, if the updated integrated value S is smaller than the life information R, the process returns to the normal operation without displaying any warning or the like (step 6).

As shown in the sequence of FIG. 3, the photosensitive member rotation time, the primary DC application time, the primary AC application time, or
The transfer bias application time is different from each other.

The inventors of the present invention have studied focusing on the damage to the photosensitive member 1 in each state in the sequence, particularly the drum scraping, and as a result, have found that the drum scraping per unit time in the state where no bias is applied. When it is set to 1, drum abrasion in a state where a primary DC bias is applied is 2 to 2.
3. It was found that the drum abrasion in the state where the primary AC bias was applied had a large difference of 8 to 10.

When the rotation speed of the photosensitive member is reduced to half speed with respect to each bias application condition, about 1/2 of the primary AC bias is applied when no bias is applied and when the primary DC bias is applied. In the applied state, when the frequency is the same, about 3/4, and when the frequency is halved, about 1 /
It turned out that it was 2. This result indicates that an OP having a surface layer using a polycarbonate resin as a main binder as a photosensitive member was obtained.
This was obtained as a result of a study using a C photosensitive member and a system using blade cleaning as the photosensitive member cleaning.

From the above examination results, it is considered that the life of the photosensitive member 1 is predominantly determined by the drum scraping.
Accurate life detection is possible by multiplying each operating speed × applied time for each bias application condition by a coefficient, estimating the amount of drum scraping by integrating the total calculated value, and judging the life.

The conventionally proposed method uses corona charging, in which the drum rotation time and the drum scraping amount are almost proportional at a constant rotation speed. Therefore, the drum rotation number or the drum rotation time is integrated. However, as described above, in a system in which contact printing is used as a charging unit, an AC bias is applied, and a photoconductor rotation speed is changed to perform a printing operation, as described above. In addition, the drum rotation time and the drum scraping amount are not proportional, so that accurate life detection cannot be performed.

The time during which AC is applied can be estimated to some extent by integrating the time during which the transfer bias is applied. However, as shown in the sequence of FIG. 3, the AC bias is higher than the image area. Since the voltage is applied for a relatively long time, and is also applied at the end of the printing operation, there is a difference from the application time Tt of the transfer bias applied almost only to the image area. The accuracy will be lost.

In this embodiment, the bias application time detecting section 23 detects the rotational speeds in one job of the printing operation and the application times t11, t12, and t under each bias application condition.
13, t22, t23, and t24 are detected, and a photoconductor damage index D is calculated by the photoconductor damage calculation unit 23 using the above-described formula and each coefficient, and the photoconductor damage integration of the photoconductor damage integration storage unit 24 is performed. By updating the value S with the latest integrated value, the drum scraping amount of the photoconductor 1 is estimated,
Accurate life detection can be performed.

In this embodiment, the sponge charging roller is used as the contact charging member. However, a solid rubber roller may be used, and the roller is not limited to the roller shape. A roller or the like may be used.

In the present embodiment, the calculation coefficients for the photoconductor damage are: k11 = 1, k12 = 0.3, k13 = 0.1, k22
= 0.15, k23 = 0.05, and k24 = 0.65, but these values vary depending on the combination of the photoconductor material, the bias application condition, the cleaning method, and the like. Good. Also, in the sequence, it does not significantly affect the scraping of the photosensitive drum (the calculation coefficient kmn is significantly smaller than k11, the application time tmn is significantly smaller than t11, etc.).
The term of the bias application condition may be omitted to the extent that required accuracy is not reduced.

In this embodiment, an example of the image forming apparatus in which the operation speed is varied when the image resolution is switched has been described. However, when the operation speed is reduced for fixing the OHT film or the thick paper, the cleaning of the transfer roller and the like is performed. Therefore, it goes without saying that the present invention is similarly applied to a case where the operation speed is increased.

In this embodiment, an example is described in which a process cartridge is used in which a photosensitive member, a charging roller, a developing device, and a cleaning device are integrated, but an image in which a single photosensitive member is replaced as a consumable item is used. It goes without saying that a similar effect is obtained in the forming apparatus.

Embodiment 2 Hereinafter, Embodiment 2 of the present invention will be described with reference to FIG. 5 and FIG.

In the present embodiment, the information for determining the life of the photoconductor is set in two stages in the photoconductor life information storage unit 27 of FIG. That is, since the life of the photosensitive member is approaching, the warning information Y for instructing the user to prepare for replacement is set, and the life information R which is the true life of the photosensitive member is set in two stages. . Naturally, the relationship is such that the warning information Y <the photoconductor life R.

In FIG. 1, the photosensitive member 1 is rotated (rotational speed, rotation ON / OFF) by the photosensitive member rotation instructing section 25.
The charging roller 2 serving as a contact charging unit is supplied with an AC bias,
DC bias is applied to primary AC voltage output instructing section 21 and primary DC
It is controlled and applied independently by the output instruction unit 20.

The primary AC voltage output instruction unit 21, the primary DC voltage output instruction unit 20, and the photoconductor rotation instruction unit 22 are connected to a bias application time detection unit 23, and have a resolution of 600 dpi.
At the time of the printing operation (rotation speed Vps1), the application time t11 of each bias application condition in one job of the printing operation,
t12 and t13 are detected. In the 1200 dpi print operation (rotation speed Vps2), the application times t22 and t22 of each bias application condition in one job of the print operation are set.
23 and t24 are detected (step 11).

After one job of the printing operation is completed, the application time t11, t12, t13, t2 of each bias application condition.
2, t23 and t24 are transferred to the photoreceptor damage calculation unit 24, and the photoreceptor damage index D is expressed by the following equation shown in the first embodiment: D = k11 × t11 + k12 × t12 + k13 × t13 + k22 × t22 + k23 × t23 + k24 × t24. .. (in the above equation, each coefficient is k11 = 1, k12 = 0.3,
k13 = 0.1, k22 = 0.15, k23 = 0.0
5, k24 = 0.65. ) (Step 12).

The photosensitive member damage accumulation storage unit 25 updates the photosensitive member damage integrated value S by adding the photosensitive member damage index D for one job to the stored photosensitive member damage integrated value S (step 13).

Next, the comparison section 26 reads the preset warning information Y and life information R from the photoconductor life storage section 27, and reads the updated integrated value S from the photoconductor damage accumulation storage section 25, First, the integrated value S is compared with the warning information Y (step 14).

As a result of the comparison, if the updated integrated value S is smaller than the warning information Y, the process returns to the normal print sequence, and the life information of the photosensitive member 1 is not displayed (step 1).
5).

On the other hand, if the result of comparing the updated integrated value S with the warning information Y is S ≧ Y, the integrated value S is compared with the life information R (step 16).

If the result is S <R, the warning unit (display unit) is instructed to prompt the user to prepare for replacement because the life of the photoconductor is approaching. It is prohibited (step 16).

On the other hand, if the result of the comparison is S ≧ R, the photosensitive member life warning unit (display unit) 28 informs the user that the photosensitive member has reached the end of its life and prompts the user to replace the photosensitive member. And the printing operation is blocked (step 1).
8). When it is confirmed that the photoconductor 1 has been newly replaced, the printing operation is permitted again.

In this embodiment, the information for judging the life of the photosensitive member is set in two stages of the warning information and the life information. It goes without saying that it may be presented to the user.

By the above, the user can sense that the life of the photosensitive member is near and the time for replacement is near, and the user can prepare a new photosensitive member in advance and immediately replace the photosensitive member when it reaches the end of its life. When the service life is reached, the apparatus is stopped, so that damage to the main body due to printing after the service life can be prevented.

Third Embodiment Hereinafter, a third embodiment of the present invention will be described with reference to FIGS. Since the schematic configuration of the image forming apparatus is the same as that of the first embodiment, only the different points will be described.

In the first embodiment, the process cartridge includes an electrophotographic photosensitive member 1, a charging roller 2, a developing device 3,
In this embodiment, the electrophotographic photosensitive member 1, the charging roller 2, and the cleaning device are integrated as a drum unit (process cartridge) 29 and attached to the main body of the device. The developing device 7 is a separate unit because it can be replaced by the guide means 80. Drum unit 29
A storage element 30 serving as a storage unit is mounted in the inside, and a connection terminal (not shown) is provided in the container of the drum unit 29 so that it can communicate with a control unit of the main body when the drum unit 29 is mounted on the image forming apparatus. Is provided.

The image forming process is the same as that of the first embodiment, and will not be described.

In FIG. 6, the photosensitive member 1 is rotated (rotation speed, rotation ON / OF) by the photosensitive member rotation instructing section 22.
F), the charging roller 2 serving as a contact charging means is supplied with an AC bias and a DC bias from a primary bias application power supply 12 as appropriate by a primary AC voltage output instruction unit 21 and a primary DC voltage output instruction unit 20 independently. Controlled and applied.

The primary AC voltage output instructing unit 21, the primary DC voltage output instructing unit 20, and the photoreceptor rotation instructing unit 22 are connected to the bias application time detecting unit 23, and perform the printing operation at 600 dpi printing operation (rotation speed Vps1). Application time t11, t for each bias application condition in one job
12, t13 are detected. Also, at the time of 1200 dpi print operation (rotation speed Vps2), 1
Application time t22, t2 of each bias application condition during job
3, t24 is detected (step 21).

After one print job is completed, the application time t11, t12, t13, t2 of each bias application condition
2, t23 and t24 are transferred to the photoreceptor damage calculation unit 24, and the photoreceptor damage index D is given by the following equation: D = k11 × t11 + k12 × t12 + k13 × t13 + k22 × t22 + k23 × t23 + k24 × t24 (in the above equation) , Each coefficient is k11 = 1, k12 = 0.3,
k13 = 0.1, k22 = 0.15, k23 = 0.0
5, k24 = 0.65. ).

The photoreceptor damage calculation unit 24 is connected to the storage element 30 in the drum unit 29, reads the photoreceptor damage integrated value Sold from the storage element 30 for each job, and stores the read value of the photoreceptor damage value for one job. Body damage index D
Is added to update the photosensitive member damage integrated value Snew stored in the storage element 30 (step 22).

In this operation, when one job of the printing operation is completed and the update of the integrated value S stored in the storage element 30 of the drum unit 29 is completed, the comparing section 26 updates the integrated value S from the storage element 30 of the drum unit 29. Integrated value S
Then, the life information R set and stored in advance is read, and the magnitude relation between them is compared (step 23).

As a result, when the updated integrated value S is larger than the life information R (S ≧ R), the warning unit (display unit) 2
8. Send a signal to 8 to warn or display that the life is over,
The printing of the main body is prohibited (step 24). On the other hand, if S <R, the display returns to the normal operation without displaying a warning or the like (step 25).

In the present embodiment, since the photosensitive element damage index D stored for each unit is different by providing the storage element 30 in the drum unit 29, the unit can be easily identified. That is, when a new unit is replaced, even if the user mistakenly installs the old unit, it can be determined without providing a special identifying means. When used, problems such as outputting a defective image can be prevented.

Further, by storing in advance the information R on the life of the photosensitive drum in the storage element 30 of the drum unit 29, even when drum units having different lifespans are mounted, the lifespan is appropriately detected in accordance with the lifespan of each, and a warning is issued. Etc. can be performed.

Embodiment 4 Next, Embodiment 4 of the present invention will be described with reference to FIG.
As in the third embodiment, the schematic configuration of the image forming apparatus according to the present embodiment is a drum unit (process cartridge) 29 by integrating the electrophotographic photosensitive member 1, the charging roller 2, and the cleaning device 14, and the developing device 7 is separate. This is an example in which a storage element 30 is mounted in a drum unit 29 as a unit. Similarly, the container of the drum unit 29 is provided with a connection terminal (not shown) so as to be able to communicate with a control unit of the main body when the main body is mounted on the main body of the image forming apparatus.

The feature of the present embodiment is that the method of detecting the life of the photosensitive member according to the first to third embodiments uses the application time t11, t12, t13 for each bias application condition in one job of the printing operation.
After detecting t22, t23, and t24 and calculating the photoconductor damage index by the photoconductor damage calculation unit, the photoconductor damage integrated value was stored in the photoconductor damage integration storage unit of the main body or the storage element of the drum unit. On the other hand, the application time t11 and t1 for each bias application condition at each rotation speed
2, t13, t22, t23 and t24 themselves are integrated and stored in respective integrated values S11, S12, S13, S22, S23 and S24, and the integrated values S11,
Read S12, S13, S22, S23, S24,
The coefficient k11, k12, k
13, k22, k23, and k24, the total photoreceptor damage index D is obtained by the following equation: D = k11 × S11 + k12 × S12 + k13 × S13 + k22 × S22 × k23 × S23 + k24 × S24... , K13, k2
The values of 2, k23 and k24 are calculated as integrated values S11, S12, S13, S22, S2 of the application time under each bias application condition.
(3) The point is changed according to the ratio of S24.

The method of detecting the life of the photosensitive member, which is a feature of the present invention, will be described with reference to the flowchart of FIG.

The rotation (rotation speed, rotation ON / OFF) of the photoreceptor 1 is controlled by a photoreceptor rotation instructing unit 22. The bias and the DC bias are controlled and applied independently by the primary AC voltage output instruction unit 21 and the primary DC voltage output instruction unit 20.

The primary AC voltage output instructing unit 21, the primary DC output instructing unit 20, and the photoreceptor rotation instructing unit 22 are connected to the bias application time detecting unit 23, and perform one of the printing operations at 600 dpi printing operation (rotation speed Vps1). Application time t11, t1 of each bias application condition during job
2, t13 is detected. In the 1200 dpi print operation (rotation speed Vps2), the application time t22, t2 of each bias application condition in one job of the print operation.
3, t24 is detected (step 31).

After one print operation job is completed, the application time t11, t12, t13, t2 of each bias application condition is set.
2, t23, and t24 are transferred to the photoconductor damage calculation unit 24, and the photoconductor damage calculation unit 24 reads the application time of the bias application condition of each stored photoconductor from the storage element 30 in the connected drum unit 29. Integrated value S11,
Read S12, S13, S22, S23, S24,
The application time t for each bias application condition during one job
11, t12, t13, t22, t23 and t24 are added, and the integrated values S11, S12, S13, S22 of the application time of each bias application condition stored in the storage element 30 are calculated.
S23 and S24 are updated (step 32).

Thereafter, the integrated values S11, S12, S13, S22, S of the application time under each updated bias application condition are set.
Using S23 and S24, the photoreceptor damage index D is calculated by the following equation: D = k11 × S11 + k12 × S12 + k13 × S13 + k22 × S22 × k23 × S23 + k24 × S24. At this time, the coefficients k11, k12, k1
The values of 3, k22, k23, and k24 are integrated values S11, S12, S13, S22 of the application time under each bias application condition.
It is appropriately adjusted by the ratio of S23 and S24.

In the present embodiment, attention is paid to the integrated values S11 and S24 of the application time when the AC bias is applied, which has the greatest influence on the photosensitive drum scraping, and the photosensitive drum rotation time (S
11 + S12 + S13 + S22 + S23 + S24) integrated value of AC bias application time (S11 + S24)
Is calculated. That is, the ratio ρ = (S11 + S24) / (S11 + S12 + S13 + S22 + S23 + S24).

Then, according to the ratio ρ, k11 = 1, k12 = 0.5 × ρ, k13 = 0.2 ×
ρ, k22 = 0.25 × ρ, k23 = 0.1 × ρ, k2
4 = 0.65 is set (step 33).

When the calculation of the photoreceptor damage index is completed,
The comparison unit 26 reads the life information R that is set and stored in advance from the storage element 30 of the drum unit 29, and compares the calculated photoconductor damage index D with the magnitude relationship (Step 34).

As a result, if the calculated photoreceptor damage index D is larger than the life information R (D ≧ R), a signal is sent to a warning section (display section) 28 to warn or display that the life is reached (step S1). 35).

If the photoreceptor damage index D is smaller than the life information R, the process returns to the normal operation without displaying a warning or the like (step 36).

As in this embodiment, the photosensitive drum rotation time (S11 + S24) of the integrated value of the AC bias application time (S11 + S24)
+ S12 + S13 + S22 + S23 + S24), the coefficients k12, k13, k22, and k23 related to the integrated values S12, S13, S22, and S23 of the DC bias application time and the time without bias application were changed based on the following experimental results. ing.

That is, as described in the first embodiment, there is a difference in the damage (mainly the shaved amount) of the photosensitive drum due to the difference in the bias application conditions such as the application of the AC bias, the application of the DC bias only, and the absence of the bias. is there. In particular, experiments confirmed that the amount of scraping of the photosensitive drum when the AC bias was applied was larger than in the other cases.

The present inventors further believe that the degree of the AC bias application time during the rotation of the photosensitive drum affects the amount of scraping of the photosensitive drum under other bias application conditions. An experiment was conducted to measure the amount of scraping of the photosensitive drum per unit time while changing the application time ratio of the AC bias during the rotation time from 50% to 70%.

As a result, as the AC bias application time ratio becomes larger, the amount of scraping of the photosensitive drum under other bias application conditions becomes smaller, assuming that the amount of scraping when the AC bias is applied is 1 DC.
It was found that when the bias was applied only, it increased from about 0.20 to 0.4, and when no bias was applied, it increased from about 0.1 to 0.15. Further, even when the rotation speed of the photosensitive drum was reduced to half speed, the change in the shaving amount under each bias application condition showed a tendency substantially similar to the above.

This experiment was performed in the same manner as in Example 1, using an OPC photoreceptor having a surface layer of polycarbonate resin as a main binder as the photoreceptor 1, and using a blade cleaning as a photoreceptor cleaning system.

Based on the above results, in this embodiment, the calculation coefficients k11, k12, k
13, k22, k23, and k24 are determined by the photosensitive drum rotation time (S11 + S12 + S13 + S22 + S23 + S24)
AC bias application time integration value (S11 + S2
4) k11 = 1, k12 = 0.5 × ρ, k13 = 0.2 ×
ρ, k22 = 0.25 × ρ, k23 = 0.1 × ρ, k2
4 = 0.65 was set.

When the life of the photosensitive drum is short (for example, about 10,000 sheets can be passed), the calculation coefficients k11, k12, k13, and d13 of the damage index of the photosensitive drum as in the first to third embodiments are used.
Even if k22, k23, and k24 are constants, the accuracy can be sufficiently improved as compared with the conventional method. However, when the life of the photosensitive drum is long (for example, about 50,000 sheets can be passed), the number of durable sheets increases in proportion. Since the error increases, the accuracy can be further improved by changing the operation coefficient as in the present embodiment.

As in this embodiment, the storage element 30 is provided in the drum unit 29, and one of the printing operations at each rotation speed is performed.
Application time t11, t1 of bias application condition during job
2, t13, t22, t23, and t24 themselves are added to respective integrated values S11, S12, S13, S22, S23, and S24 and stored in the storage element 30, and the integrated values S11, S12, S13, S22, and S23,
S24 is read out, and the integrated values S11, S12, S13, S22, S23, S2
Coefficients k11, k12, k13, k determined by the ratio of 4.
By using a method of calculating the total photoconductor damage index D using 22, k23, and k24, the life of the photoconductor can be accurately estimated.

In addition, by collecting the used drum unit 29, it is possible to collect a lot of information on the actual situation of use in the market. Can be achieved.

However, for the purpose of accurately estimating the life of the photosensitive member, the application time t of each bias application condition is set.
The integrated values S11, S12, S13, S22, S23, and S24 of 11, t12, t13, t22, t23, and t24 may be stored in the image forming apparatus main body.
The application time t of each bias application condition in one job
After detecting t11, t12, t13, t22, t23, and t24 and calculating the photoconductor damage index by the photoconductor damage calculation unit, the photoconductor damage integration value is stored in the photoconductor damage integration storage unit of the main body or the storage element of the drum unit. In the storage method, when calculating the photoconductor damage index for each job, the coefficients k11, k12, and k13 are calculated from the ratios of the application times t11, t12, t13, t22, t23, and t24 of each bias application condition in one job. , K22, k2
3. Even if k24 is changed and the photoconductor damage index in one job is obtained, the same effect can be obtained.

Further, in the present embodiment, the coefficient is calculated as k11 =
1, k12 = 0.5 × ρ, k13 = 0.2 × ρ, k22
= 0.25 × ρ, k23 = 0.1 × ρ, k24 = 0.6
Although the value is set to 5, the value varies depending on the combination of the photoconductor material, the bias application condition, the cleaning method, and the like. Therefore, the optimum value and the variable method may be appropriately selected in each system.

Further, the AC bias voltage value and the current value are changed by the fluctuation of the resistance of the charging means due to environmental fluctuation, fluctuation of durability and the like, and the fluctuation of the capacity of the photosensitive drum due to the scraping of the photosensitive drum.
If the amount of damage to the photosensitive drum changes,
It is also effective to provide a means for detecting the voltage value or current value of the AC bias, and thereby change the operation coefficient when the AC bias is applied.

[0130]

As is apparent from the above description, according to the present invention, it is possible to accurately detect the life of the image carrier, and to accurately determine that the replacement time due to the life of the image carrier is near. Since it is possible to detect and thus replace a new process cartridge in advance and immediately replace it when it reaches the end of its service life, the downtime of the image forming apparatus can be shortened to improve work efficiency. Since the image forming apparatus is stopped, even if the display or warning prompting replacement is ignored and the apparatus is used without damaging the apparatus, the life of the image carrier is not damaged, and image forming using the life detecting method is performed. An apparatus, a process cartridge, and an image forming apparatus including the process cartridge can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to a first exemplary embodiment.

FIG. 2 is a configuration diagram illustrating a process cartridge that can be attached to and detached from the image forming apparatus of FIG. 1;

FIG. 3 is a diagram illustrating an image forming sequence of the image forming apparatus of FIG. 1;

FIG. 4 is a flowchart of life detection according to the first embodiment.

FIG. 5 is a flowchart of life detection of the image forming apparatus according to the second embodiment.

FIG. 6 is a schematic configuration diagram illustrating an image forming apparatus according to a third embodiment and a fourth embodiment.

FIG. 7 is a flowchart for detecting the life of the image forming apparatus according to the third embodiment.

FIG. 8 is a flowchart for detecting the life of the image forming apparatus according to the fourth embodiment.

[Explanation of symbols]

Reference Signs List 1 photosensitive drum (image carrier) 2 charging roller (charging unit) 7 developing device (developing unit) 10 developing sleeve 14 cleaning unit 17, 29 process cartridge 23 bias application time detecting unit (detecting unit) 24 photoconductor damage calculating unit ( Computing unit) 25 Photoconductor damage accumulation storage unit (integration unit) 26 Comparison unit (comparison unit) 28 Warning unit (display unit / warning unit / notification unit) 30 Storage element (storage unit) 70 Transport unit 80 Mounting unit

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) G03G 21/00 370-540 G03G 15/00 303 G03G 15/02-15/02 103 G03G 21/00 350 G03G 21/18

Claims (20)

(57) [Claims] 1. A method for detecting the life of an image carrier in an image forming apparatus having at least an image carrier and a charging unit applied with a voltage and in contact with the image carrier, wherein the applied voltage includes a DC bias component and an AC bias component. And m (m ≧ 2) operation speeds Vm and n (n ≧ 1) bias application conditions during the image forming operation, and the bias application condition n under the operation speed Vm Time tm during which a bias is applied to the charging means
n, and using the detected time tmn and a predetermined coefficient kmn, the damage index D of the image carrier is calculated as follows: D = k11 × t11 + k21 × t21 +... + kmn
× tmn (where k11> 0, k21... Kmn ≧ 0), and the obtained damage index D is integrated.
An image carrier life detecting method, wherein the life of the image carrier is determined by comparing the integrated value S with life information R which is a predetermined life of the image carrier. 2. The image carrier according to claim 1, wherein the value of the coefficient k21... Kmn is changed according to the ratio of time t11, t21. Body life detection method. 3. A method for detecting the life of an image carrier in an image forming apparatus having at least an image carrier and a charging unit applied with a voltage and in contact with the image carrier, wherein the applied voltage is a DC bias component and an AC bias component. And has m (m ≧ 2) operation speeds Vm and n (n ≧ 1) bias application conditions during the image forming operation;
Under the operating speed Vm, a time tmn during which a bias is applied to the charging means is detected based on a bias application condition n, and the detected times t11, t21... Tmn are integrated, and the integrated time integrated value S11 is calculated. , S21 ... Smn
The damage index D of the image carrier is calculated using the following equation: D = k11 × S11 + k21 × S21 +... + Kmn
× Smn (where k11> 0, k21... Kmn ≧ 0), and the calculated damage index D of the image carrier and a predetermined lifetime are defined as the lifetime of the image carrier. A method for detecting the life of the image carrier, comprising determining the life of the image carrier by comparing the information with information R. 4. The method according to claim 3, wherein when calculating the damage index D of the image carrier, the values of the coefficients k21... Kmn are changed according to the ratio of the time integrated values S11, S21. Image carrier life detection method. 5. An image forming apparatus having at least an image carrier and a charging unit applied with a voltage and in contact with the image carrier, the applied voltage includes a DC bias component and an AC bias component, and an image forming operation is performed. Among them, there are m kinds (m ≧ 2) of operation speeds Vm and n kinds (n ≧ 1) of bias application conditions, and a bias is applied to the charging means under the operation speed Vm based on the bias application condition n. Using a detecting means for detecting the time tmn and the time detected by the detecting means and a predetermined coefficient kmn, the damage index D of the image carrier is calculated as follows: D = k11 × t11 + k21 × t21 +... + Kmn
× tmn (where k11> 0, k21... Kmn ≧ 0), and a damage index D of the image carrier.
Means for integrating the integrated value into the integrated value S, means for comparing the integrated value S integrated by the integrating means with a predetermined lifetime information R as the life of the image carrier, and a comparison between the comparing means. Warning means or notification for warning or displaying the life of the image carrier when the integrated value of the image carrier damage integrated by the integration means based on the result is equal to or longer than a predetermined integration time as the life of the image carrier. And an image forming apparatus. 6. An image forming apparatus having at least an image carrier and a charging unit applied with a voltage and in contact with the image carrier, the applied voltage includes a DC bias component and an AC bias component, and an image forming operation is performed. Among them, there are m kinds (m ≧ 2) of operation speeds Vm and n kinds (n ≧ 1) of bias application conditions, and a bias is applied to the charging means based on the bias application condition n under the operation speed Vm. .. + Kmn using a detecting means for detecting the time tmn, and a time detected by the detecting means and a predetermined coefficient kmn, the damage index D of the image carrier is calculated as follows: D = k11 × t11 + k21 × t21 +.
× tmn (where k11> 0, k21... Kmn ≧ 0), and a damage index D of the image carrier.
Integrating means for integrating the image bearing member, and life information R indicating the life of the image bearing member and a predetermined value of the integrated value S, or replacing the image bearing member before the image bearing member reaches the end of its life. And comparing means for comparing the warning information Y smaller than at least one or more pieces of predetermined life information R in order to prompt the preparation. The comparing means accumulates based on the comparison result of the comparing means. When the integrated value S is equal to or more than the predetermined warning information Y, a warning or display is provided for the preparation for replacing the image carrier, and based on the result of the comparing means, the integrated value S integrated by the integrating means is determined in advance. An image forming apparatus which warns or displays the life of the image carrier when the life information is equal to or longer than the life information R, and stops the image forming operation of the main body. 7. An image forming apparatus in which a process cartridge including at least an image carrier is detachably mountable to an apparatus main body and has a charging unit to which a voltage is applied and comes into contact with the image carrier, the process cartridge includes a storage element. And the voltage applied to the charging means is a DC bias component and A
Including a C bias component and during the image forming operation,
m kinds (m ≧ 2) of operating speeds Vm and n kinds (n ≧ 1)
Detecting means for detecting the time tmn during which the bias is applied to the charging means based on the bias applying condition n under the operating speed Vm, and the time detected by the detecting means and a predetermined time. Using the coefficient kmn, the damage index D of the image carrier is calculated as follows: D = k11 × t11 + k21 × t21 +... + Kmn
× tmn (where k11> 0, k21... Kmn ≧ 0), and a damage index D of the image carrier.
An image forming apparatus comprising: an integrating means for integrating the integrated value into an integrated value S; and a means for writing the integrated value S to the storage element and reading the content. 8. An image forming apparatus in which a process cartridge including at least an image carrier is detachably mountable to an apparatus main body and has a charging unit to which a voltage is applied and comes into contact with the image carrier, the process cartridge includes at least an image carrier. A storage element for storing information R on the life of the body, wherein a voltage applied to the charging means is a DC bias component and A
Including a C bias component and during the image forming operation,
m kinds (m ≧ 2) of operating speeds Vm and n kinds (n ≧ 1)
Detecting means for detecting the time tmn during which the bias is applied to the charging means based on the bias applying condition n under the operating speed Vm, and the time detected by the detecting means and a predetermined time. Using the coefficient kmn, the damage index D of the image carrier is calculated as follows: D = k11 × t11 + k21 × t21 +... + Kmn
× tmn (where k11> 0, k21... Kmn ≧ 0), and a damage index D of the image carrier.
Integrating means, and the integrated value S by the integrating means
Means for writing in the storage element and reading out the integrated value S and the information R on the lifetime. 9. The method according to claim 5, wherein when calculating the damage index D of the image carrier by the calculating means, the values of the coefficients k21... Kmn are changed according to the ratio of times t11, t21. 9. The image forming apparatus according to any one of items 1 to 8. 10. An image forming apparatus having at least an image carrier and a charging unit applied with a voltage and in contact with the image carrier, wherein the applied voltage is a DC bias component and an AC voltage.
M including a bias component and during the image forming operation.
There are two types (m ≧ 2) of operating speeds Vm and n types (n ≧ 1) of bias application conditions. The detecting means for detecting, the integrating means for integrating the times t11, t21,... Tmn detected by the detecting means, and the integrated values S11, S21,.
Smn and predetermined coefficients k11, k21,.
mn, the damage index D of the image carrier is calculated as follows: D = k11 × S11 + k21 × S21 +... + kmn
× Smn (where k11> 0, k21... Kmn ≧ 0), and a damage index D of the image carrier.
And a lifetime information R which is a predetermined life of the image carrier; and a damage index D based on the comparison result of the comparison means, which is a predetermined lifetime of the image carrier. An image forming apparatus comprising: a warning unit or a notification unit that warns or displays the life of the image carrier when the time is longer than a predetermined time. 11. An image forming apparatus having at least an image carrier and a charging unit applied with a voltage and in contact with the image carrier, wherein the applied voltage is a DC bias component and an AC voltage.
M including a bias component and during the image forming operation.
It has a type (m ≧ 2) of operation speed Vm and n types (n ≧ 1) of bias application conditions, and detects a time tmn during which a bias is applied to the charging means under the operation speed Vm based on the bias application condition n. .. Tmn detected by the detecting means, integrating means for integrating the times t11, t21,... Tmn detected by the detecting means, and integrated time integrated values S11, S21,.
Smn and predetermined coefficients k11, k21,.
mn, the damage index D of the image carrier is calculated as follows: D = k11 × S11 + k21 × S21 +... + kmn
× Smn (where k11> 0, k21... Kmn ≧ 0), and a damage index D of the image carrier.
Life information R, which is the life of the image carrier, determined in advance,
Or comparing means for comparing warning information Y smaller than at least one or more predetermined life information R in order to prompt preparation for replacement of the image carrier before the life of the image carrier has expired; When the damage index D is equal to or more than the predetermined warning information Y based on the comparison result of the comparing means, a warning or display is provided for the preparation for replacing the image carrier, and based on the result of the comparing means, the damage index D is determined in advance. An image forming apparatus, which warns or displays the life of an image carrier that is equal to or longer than predetermined life information R and stops the image forming operation of the main body. 12. An image forming apparatus in which a process cartridge including at least an image carrier is detachably mountable to an apparatus main body and has a charging unit to which a voltage is applied and comes into contact with the image carrier, the process cartridge includes a storage element. And the voltage applied to the charging means is a DC bias component and A
Including a C bias component and during the image forming operation,
m kinds (m ≧ 2) of operating speeds Vm and n kinds (n ≧ 1)
, And a detecting means for detecting a time tmn during which a bias is applied to the charging means based on the bias applying condition n under the operating speed Vm, and integrating the detected times t11, t12,... Tmn. Means for calculating
An image forming apparatus comprising: means for writing the obtained time integrated values S11, S21,... Smn to the storage element and reading the contents. 13. An image forming apparatus in which a process cartridge including at least an image carrier is detachably attached to an apparatus main body, and has a charging unit to which a voltage is applied and comes into contact with said image carrier, said process cartridge is at least an image carrier. And a storage element for storing information R relating to the life of the device.
Including a C bias component and during the image forming operation,
m kinds (m ≧ 2) of operating speeds Vm and n kinds (n ≧ 1)
, And a detecting means for detecting a time tmn during which a bias is applied to the charging means based on the bias applying condition n under the operating speed Vm, and integrating the detected times t11, t12,... Tmn. Means for calculating
The obtained time integrated values S11, S21... Smn are written in the storage element, and the time integrated values S11, S2
1. An image forming apparatus comprising: means for reading information R relating to Smn and life. 14. When the calculating means calculates the damage index D of the image carrier, the time integrated values S11, S21,.
14. The image forming apparatus according to claim 10, wherein a value of the coefficient k21... kmn is changed according to a ratio of mn. 15. A process cartridge which is detachably attached to a main body of an image forming apparatus having a charging unit which is in contact with an image bearing member when a voltage is applied thereto, includes at least a storage element in a process cartridge including the image bearing member, and The applied voltage is D
M types (m ≧ 2) of operation speeds Vm including the C bias component and the AC bias component and during the image forming operation
And n types (n ≧ 1) of bias application conditions, and the image forming apparatus main body detects the time tmn during which the bias is applied to the charging unit based on the bias application condition n under the operation speed Vm. Using the time detected by the detecting means and a predetermined coefficient kmn, the damage index D of the image carrier is calculated as follows: D = k11 × t11 + k21 × t21 +... + Kmn
× tmn (where k11> 0, k21... Kmn ≧ 0), and a damage index D of the image carrier.
And a means for writing the integrated value S to the storage element and reading the content. 16. A process cartridge including at least the image carrier detachably mountable to an image forming apparatus main body having a charging unit applied with a voltage and contacting the image carrier.
A storage element storing at least information R on the life of the image carrier; a voltage applied to the charging unit includes a DC bias component and an AC bias component; and m types (m ≧ 2) during an image forming operation. The image forming apparatus main body has an operation speed Vm and n kinds of (n ≧ 1) bias application conditions, and the image forming apparatus main body detects a time tmn during which a bias is applied to the charging unit under the operation speed Vm based on the bias application condition n. .. + Kmn, using a detection unit that performs the detection, and the time detected by the detection unit and a predetermined coefficient kmn, to calculate the damage index D of the image carrier. D = k11 × t11 + k21 × t21 +.
× tmn (where k11> 0, k21... Kmn ≧ 0), and a damage index D of the image carrier.
And a means for writing the obtained integrated value S into the storage element and reading out the information R on the integrated value S and the life. 17. The method according to claim 1, wherein the calculating means changes the value of the coefficient k21... Kmn according to the ratio of time t11, t21. 15 or 16 process cartridges. 18. A process cartridge including at least an image carrier, which is detachable from an image forming apparatus having a charging unit which is in contact with an image carrier and which is applied with a voltage, wherein the process cartridge includes a storage element and is connected to the charging unit. Applied voltage includes a DC bias component and an AC bias component, and has m kinds (m ≧ 2) of operation speeds Vm and n kinds (n ≧ 1) of bias application conditions during the image forming operation. The forming apparatus main body includes a detecting unit that detects a time tmn during which the bias is applied to the charging unit based on the bias applying condition n under the operation speed Vm, and an integrating unit that integrates the detected times t11, t12,. , And means for writing the obtained time integrated values S11, S21,... Smn to the storage element and reading the contents. Process cartridge. 19. A process cartridge including at least the image carrier detachably mountable to an image forming apparatus main body having a charging unit applied with a voltage and contacting the image carrier, wherein at least information R relating to the life of the image carrier is stored. The voltage applied to the charging means includes a DC bias component and an AC bias component, and includes m types (m ≧ 2) of operation speeds Vm and n types (n ≧ 1) during an image forming operation. And the time tmn during which the bias is applied to the charging means under the operation speed Vm based on the bias application condition n.
Detecting means for detecting the times t11 and t12
... Integrating means for integrating tmn, and means for writing the obtained time integrated values S11, S21... Smn in the storage element, and for reading the integrated values S11, S21. And a process cartridge comprising: 20. At the time of calculating the damage index D of the image carrier by the calculating means, the time integrated values S11, S21,.
20. The process cartridge according to claim 18, wherein the values of the coefficients k21... kmn are changed according to the ratio of mn.