JP3285785B2 - 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 of detecting the life of an image carrier used in an image forming apparatus, an image forming apparatus using the method of operating the image carrier, and a process cartridge used in the image forming apparatus. is there.

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 a cartridge in which a charging unit, a developing unit or a cleaning unit and an image carrier are integrally formed into a cartridge, and this cartridge is detachable from an electrophotographic image forming apparatus main body. Alternatively, at least one of the charging unit, the developing unit, and the cleaning unit and the image carrier may be integrally formed as a cartridge so as to be detachable from the main body of the electrophotographic image forming apparatus. It refers to an integrated cartridge that can be attached to and detached from the electrophotographic image forming apparatus main body.

[0004]

2. Description of the Related Art Conventionally, in an image forming apparatus, there have been the following methods for detecting the life of an image carrier (generally, a photosensitive drum is often used).

Conventional example 1: Method of accumulating the number of prints (copies) The simplest method is to use the same one sheet in the case of A4 size and A3 size, even if the print (copy) size is different. There is a drawback that the accuracy of life detection is not good because counting is performed. 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 a merit 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 is constituted by 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 to add up the number of prints and stop the apparatus to make it unusable when the guaranteed life of the image carrier has come. In the meantime, a message is displayed to indicate that the replacement time is running short and to prompt the user to prepare, and to display that the time to stop the apparatus when the device is used continuously is approaching.

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 unit are usually set so that the number of prints is prioritized. When the image carrier is likely to become full earlier than the guaranteed number of image carriers, the latter function functions.

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.

Accordingly, when an attempt is made to detect the life of the photosensitive drum in an image forming apparatus using contact charging with a plurality of charging conditions during image formation, using both an AC voltage and a DC voltage as charging means. With the conventional life detection method using the number of rotations of the drum, it is difficult to accurately predict the life of the photosensitive drum, and when the life has expired and no image failure has occurred, no warning is given or the life has not yet come. There is a possibility that an inconvenience of giving a warning may occur.

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

[0029]

The above object is achieved by a method for detecting the life of an image carrier, an image forming apparatus and a process cartridge using the method, and an image forming apparatus provided with the process cartridge according to the present invention. You. In summary, the present invention relates to a method for detecting the life of an image carrier in an image forming apparatus in which a process cartridge including at least an image carrier is detachable, wherein the process cartridge includes a storage unit and is configured to contact the image carrier. The voltage applied to the charging means for charging the image carrier includes a DC bias component and an AC bias component, and during rotation of the image carrier, no bias is applied, only a DC bias is applied, and an AC bias is applied. N of the three (n ≧
In the bias application condition 2) or during the rotation of the image carrier, no bias is applied, an AC bias is applied, and the voltage or current value or the frequency of the AC bias is reduced to apply n (n) .Gtoreq.2), and in the main body of the image forming apparatus, respective times t1, t2,.
By using tn and coefficients k1, k2,... kn, the damage index D of the image carrier is calculated as follows: D = k1 × t1 + k2 × t2 +... + kn × tn (where t1 is the AC bias application time and k1> 0) , K2
> 0, k3.gtoreq.0,..., Kn.gtoreq.0), the damage index D of the image carrier is integrated into the image carrier damage integrated value S, and the integrated value S is calculated in advance. By comparing with the determined life information R of the image carrier,
The life of the image carrier is determined, and the coefficient is stored in the storage unit and can be changed for each process cartridge.

The integrated value S and the life information R are calculated.
When the integrated image carrier damage integrated value S is equal to or more than the life information R of the image carrier based on the comparison result with
It is preferable to warn or display the life of the image carrier.

The integrated value S is compared with at least one predetermined warning information Y smaller than the life information R, and the integrated value S is larger than the warning information Y and is calculated from the life information R. If it is smaller, it is preferable to prompt the user to replace the process cartridge including the image carrier.

[0032]

The storage means stores the life information R and the warning information Y. When the comparison means compares the life information R and the warning information Y, the comparison may be performed based on the life information R and the warning information Y. preferable.

The integrated value S is preferably stored in the storage means.

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 detachable, the process cartridge includes a storage unit, and contacts the image carrier in contact with the image carrier. The voltage applied to the charging means for charging the body includes a DC bias component and an AC bias component. During rotation of the image carrier, no bias is applied, only a DC bias is applied, and an AC bias is applied. n types (n ≧ 2)
Bias application conditions, or no bias application, AC bias application,
There are n types (n ≧ 2) of bias application conditions from among the three types of application by lowering the bias voltage value or current value or frequency, and the respective time t1, t2... Tn in the bias application condition n Using the coefficients k1, k2,... Kn, the damage index D of the image carrier is calculated as follows: D = k1 × t1 + k2 × t2 +... + Kn × tn (where t1 is the AC bias application time and k1> 0, k2
> 0, k3 ≧ 0,..., Kn ≧ 0), an integrating means for integrating the damage index D of the image carrier into an integrated value of the image carrier damage, and an integrating means. A means for comparing the integrated value with life information indicating a predetermined life of the image carrier; and an image carrier damage integrated value integrated by the integrating means based on a result of the comparing means. Warning means or notifying means for warning or displaying the life of the image carrier when the life is equal to or more than the life information, wherein the coefficient is stored in the storage means and can be changed for each process cartridge An image forming apparatus is provided.

According to another aspect of the present invention, in a process cartridge detachable from an image forming apparatus main body, an image carrier and at least a charging device which contacts the image carrier and charges the image carrier. A process unit having a unit, and a storage unit, wherein the voltage applied to the charging unit includes a DC bias component and an AC bias component, and no bias is applied during rotation of the image carrier.
N-type (n ≧ 2) bias application conditions out of three of the DC bias application and AC bias application, or no bias application, AC bias application, and voltage value of this AC bias during rotation of the image carrier Alternatively, the image forming apparatus main body has n types (n ≧ 2) of bias application conditions from among the three types of application by lowering the current value or the frequency, and the image forming apparatus main body performs the respective times t1 and t in the bias application conditions n
2... Tn and coefficients k1, k2.
The damage index D of the image carrier is given by: D = k1 × t1 + k2 × t2 +... + Kn × tn (where t1 is the AC bias application time, k1> 0, k2
> 0, k3 ≧ 0,..., Kn ≧ 0), an integrating means for integrating the damage index D of the image carrier into an integrated value of the image carrier damage, and an integrating means. A means for comparing the integrated value with life information indicating a predetermined life of the image carrier; and an image carrier damage integrated value integrated by the integrating means based on a result of the comparing means. Warning means or notifying means for warning or displaying the life of the image carrier when the life is equal to or more than the life information, wherein the coefficient is stored in the storage means and can be changed for each process cartridge A process cartridge is provided.

[0037]

[0038]

[0039]

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.

As shown in FIG. 2, the printer of this embodiment integrates a photosensitive drum 1 (image carrier), a charging roller 2 and a cleaning device 14 into a drum unit (process cartridge) 29, and The device 7 is a separate unit. The storage element 30 is mounted in the drum unit 29. The container 29a 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 container 29a is mounted on the image forming apparatus. Further, 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 image forming process of the printer having the above-described structure will be described below.

The photoreceptor 1 has an outer diameter of 30 mm, and is formed by laminating a photoconductive photosensitive layer 1a on the surface of a conductive base 1b made of aluminum.
It is driven to rotate at a peripheral speed of sec.

The photoreceptor 1 receives a uniform negative polarity charge by the charging roller 2, and then outputs a laser scanner 4, which is a time-series electric digital image signal of image information sent from a video controller (not shown). Is scanned and exposed at a resolution of 600 dpi, and an electrostatic latent image is formed on the surface via a mirror 6 installed in the main body of the image forming apparatus.

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 system, and includes a developing sleeve 11 which is a rotatably supported toner carrying member which carries the toner 8 and conveys it to the photosensitive member 1. The image forming apparatus includes a magnetic field generation unit 10 fixed in the developing sleeve 11 and the 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 by the toner regulating member 9 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 on 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 configured to rotate following the photoconductor 1.

The charging roller 2 is connected to a primary bias application power supply 12 through a cored bar 2a. In this embodiment, during the rotation of the photosensitive member, an AC bias is applied to a part including the image forming area as the bias application condition 1. (Peak-to-peak voltage 1
A bias in which a DC bias of -700 V is superimposed on 600 V, a frequency of 1000 Hz, and a sine wave is applied to uniformly charge the surface of the photoconductor 1 to about -680 V. In other parts during rotation of the photoconductor, the bias application condition 2 is set to −12.
There are a portion where only 50 V is applied and the surface of the photosensitive member 1 is charged to about -680 V, and a portion where no bias is applied as the bias application condition 3 (see FIG. 3).

Here, in this embodiment, bias application condition 1; in order to obtain a uniform good image in the image area,
Further, an AC bias is used to eliminate the surface potential at the end of printing. Bias application condition 2; particularly, a uniform surface potential is not required, but unnecessary development of toner from a developing device is prevented, and transfer member cleaning is performed. Surface potential is required, and DC with less damage to the photosensitive drum
Bias application condition 3 using only a bias; no bias is applied because no particular surface potential is required;
It has been switched for the purpose of.

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 for detecting the life of the photosensitive member, which is a characteristic part of the present invention, will be described. FIG. 4 is a flowchart showing a method for detecting the life of the photoconductor.

In FIGS. 1 and 4, the rotation of the photosensitive member 1 is controlled by a photosensitive member rotation instructing section 22, and the charging roller 2 serving as a contact charging member is supplied with an AC power from a primary bias application power supply 12 as appropriate. Bias and DC bias are primary A
The C voltage output instructing section 21 and the primary DC voltage output instructing section 20 independently control and apply. 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 to apply each bias application condition in one job of the printing operation. Times t1, t2, and t3 are detected.

Here, as shown in the printing operation sequence of FIG. 3, t1 is the application time information Tac (t1 = Tac = Tac1 + Tac) from the primary AC voltage output instruction unit 21.
2), t2 is a time Ta during which the primary AC voltage is superimposed from the application time information tdc from the primary DC voltage output instructing section 20.
The value obtained by subtracting cdc (t2 = Tdc−Tacdc), t
Reference numeral 3 denotes photoconductor rotation time information T from the photoconductor rotation instruction unit 22.
dr minus t1, t2 (t3 = Tdr- (t
1 + t2)).

As described above, the bias application time detector 2
At 3, the application time t1, 2t, t under each bias application condition
3 is detected (step 1 (S1)).

After one printing operation is completed, the application time t1, t2, t3 of each bias application condition and the photoconductor calculation coefficients k1, k2, k3 in the storage element 30 are passed to the photoconductor damage calculation unit 24. (S2), the photoconductor damage index D is calculated by the following equation (S3).

D = k1 × t1 + k2 × t1 + k3 × t3 (where the coefficients are k1 = 1, k2 = 0.3, k3
= 0.1. The photoconductor damage calculation unit 24 reads the photoconductor damage integrated value S stored from the storage element 30 for each job, adds the photoconductor damage index D for one job to the photoconductor damage integrated value S, Update the photoconductor damage integrated value S (Snew = Sold + D, S
4). This operation is repeated for each job of the printing operation.

When one job has been completed and the update of the integrated value S stored in the storage element 30 of the drum unit 29 has been completed, the comparison unit 26
Then, the updated integrated value S and the preset life information R are read, and the magnitude relation with the updated photosensitive member damage integrated value S is compared (S5, S7).

As a result, when the updated integrated value S is larger than the life information R, the photoconductor life warning unit (display unit) 2
8 to warn or display the end of life (S6).

If it is determined in step 5 (S5) that the photosensitive member damage integrated value S is smaller than the warning (lifetime) information, no warning is displayed, and the process returns to the normal operation (S8).

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 during the sequence, particularly the drum scraping, and as a result, the drum scraping in the state where no bias is applied is set to 1. It was found that there was a large difference between 2 and 3 for the drum scraping with the primary DC bias applied and 8 to 10 for the drum scraping with the primary AC bias applied. This result indicates that an O layer having a surface layer using a polycarbonate resin as a main binder as a photoreceptor was obtained.
The results were obtained by examining a system using a PC photoreceptor and using blade cleaning as the photoreceptor cleaning.

From the above examination results, it is considered that the life of the photosensitive member 1 is predominantly determined by the drum scraping.
The application time for each bias application condition is multiplied by a coefficient, and the sum of the calculated values is integrated to estimate the drum scraping amount,
By judging the life, accurate life detection can be performed.

In the conventionally proposed method, the corona charging, in which the drum rotation time is substantially proportional to the drum scraping amount, is used. Therefore, by accurately integrating the number of rotations of the drum or the rotation time of the drum, the life can be accurately detected. However, as described above, in a system in which contact charging is used as the charging means and an AC bias is applied, the drum rotation time and the drum scraping amount are not proportional, and accurate life detection cannot be performed.

It is possible to estimate the time during which AC is applied 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 Ttr of the transfer bias applied almost only to the image area. The accuracy will be lost.

In this embodiment, the application time t1, t2, t3 of each bias application condition in one job of the printing operation is detected by the bias application time detector 23, and the photoconductor damage index is calculated by the photoconductor damage calculator 24. D is calculated using the above equation and the respective coefficients, and the photosensitive member damage integrated value S is updated with the latest integrated value, whereby the photosensitive member 1
The amount of drum abrasion can be estimated, and accurate life detection can be performed.

Since the storage element 30 is provided in the drum unit 29, the photoreceptor damage index stored for each unit is different, so that 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. Use of the device can prevent problems such as outputting a defective image.

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

Further, the photoreceptor calculation coefficients k1, k2, and k3 can be changed for each photoreceptor or for each lot of photoreceptors, and can cope with variations in the characteristics of the photoreceptor materials. Appropriate 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 present invention is not limited to the roller shape. , A brush roller, or the like.

Further, in the sequence, there is no significant effect on the scraping of the photosensitive drum (the operation coefficient kn is k1).
, The application time tn is significantly smaller than t1, etc.). The term of the bias application condition may be omitted to the extent that the required accuracy is not reduced.

In this embodiment, the photoconductor calculation coefficients K1, k2, and k3 in the storage element 30 are stored for each job.
Has been passed to the photoreceptor damage calculation unit 24, but may be performed only once when the power of the apparatus main body is turned on.

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

In this embodiment, 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 magnitude relationship between the two is such that the warning information Y <the photoconductor life R.

In FIG. 1, the rotation of the photoreceptor 1 is controlled by a photoreceptor rotation instructing unit 22, and a charging roller 2 serving as a contact charging member is appropriately supplied with an AC bias and a DC bias from a primary bias application power supply 12. Are controlled and applied independently by the primary AC voltage output instruction section 21 and the primary DC output instruction section 20.

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 the bias application time detecting unit 23, and each bias in one job of the printing operation is performed. Application time of application conditions t1, t
2, t3 are detected (S11).

After one print job is completed, the application time t1, t2, t3 of each bias application condition and the photoconductor calculation coefficients k1, k2, k3 in the storage element 30 are passed to the photoconductor damage calculation unit 24. (S12). Here, the photoconductor damage calculation unit 24 is connected to the storage element 30 in the drum unit 29. Next, the photoconductor damage index D is expressed by the following equation shown in the first embodiment: D = k1 × t1 + k2 × t2 + k3 × t3 (where the coefficients are k1 = 1, k2 = 0. 3, k3
= 0.1. ) (S13).

The photoreceptor damage calculation unit 24 reads the photoreceptor damage integrated value S stored from the storage element 30 for each job, adds the photoreceptor damage index D for one job to the value, and The body damage integrated value S is updated (Snew = Sold + D, S14). This operation is repeated for each job of the printing operation.

When one job is completed and the update of the integrated value S stored in the photoconductor damage accumulation storage unit 25 of the storage element 30 is completed, the comparison unit 26 reads out the photoconductor life storage unit 27 of the storage element 30 from the storage unit 30. The warning information Y and the life information R set in advance are read (S17), and the updated integrated value S is read from the photoconductor damage integrated storage unit 25 of the storage element 30.

In the comparing section 26, first, the integrated value S is compared with the warning information Y (S15). As a result, if the updated integrated value S is smaller than the warning information Y, the process returns to the normal print sequence. The life information of the photoconductor 1 is not displayed (S18).

If the result of comparing the integrated value S with the warning information Y is S ≧ Y, the integrated value S is compared with the life information R (S16).

If the result of the comparison is S <R, the user has approached the photosensitive member life at the photosensitive member life warning unit (display unit) 28, so that the user is prompted to prepare for replacement while continuing normal operation. (S19).

On the other hand, if the result of comparison is S ≧ R, the photosensitive member life warning section (display section) 28 informs the user that the photosensitive member has reached the end of life and prompts the user to replace the photosensitive member. And the printing operation is blocked. When it is confirmed that the photoconductor 1 has been newly replaced, the printing operation is permitted again (S20).

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 is needless to say that the notification may be made.

Embodiment 3 Hereinafter, Embodiment 3 of the present invention will be described with reference to FIGS. 1, 6, and 7. 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 present embodiment, the storage element 30 does not have photoconductor calculation coefficients k1, k2, and k3, but has photoconductor coefficient selection information I. This photoconductor coefficient selection information I
Is, for example, 1 as shown in the photoreceptor coefficient table of FIG.
It consists of zero information I, and each information I is associated with a different combination of photoreceptor operation coefficients k1, k2, and k3. The photoconductor damage calculation unit 24 selects one of the combinations of photoconductor calculation coefficients k1, k2, and k3 based on the photoconductor life coefficient selection information I in the storage element 30 according to the photoconductor coefficient table in FIG. And perform an operation.

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

In FIG. 1, the rotation of the photosensitive member 1 is controlled by a photosensitive member rotation instructing section 25, and a primary bias application power supply 12 is applied to the charging roller 2 as a contact charging member.
More appropriately, the AC bias and the DC bias are independently controlled and applied by the primary AC voltage output instruction section 21 and the primary DC voltage output instruction section 20.

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. Application time t of bias application condition
1, t2 and t3 are detected (S21).

After one job of the printing operation is completed, the application time t1, t2, t3 of each bias application condition and the photoconductor calculation coefficient selection information I in the storage element 30 are passed to the photoconductor damage calculation unit 24 ( S22). The photoreceptor damage calculation unit 24 is connected to the storage element 30 in the drum unit 29. Here, the photoconductor damage calculation unit 24
Selects a set of calculation coefficients k1, k2, and k3 based on photoconductor calculation coefficient selection information I (S23). Next, the photoreceptor damage index D is calculated by the following equation: D = k1 × t1 + k2 × t2 + k3 × t3 (S24).

Further, the photoconductor damage calculating section 24 updates the photoconductor damage integrated value S by adding the photoconductor damage index D for one job to the stored photoconductor damage integrated value S (S25). This operation is repeated for each job of the printing operation.

When the updating of the integrated value S stored in the storage element 30 of the drum unit 29 is completed, the comparing section 26
The updated integrated value S and the life information R set and stored in advance are read from the storage element 30 of the drum unit 29 (S28), and the magnitude relation between the two is compared (S2).
6). As a result, when the updated integrated value S is larger than the life information R (S ≧ R), a signal is sent to the photoconductor life warning unit (display unit) 28 to warn or display that the life is over, and Printing is prohibited (S27).

As a result of the comparison, when the integrated value S is smaller than the life information R (S <R), the process returns to the normal operation without displaying a warning (S29).

In this embodiment, the drum unit 30
By having the photoconductor coefficient selection information I instead of having the photoconductor operation coefficients k1, k2, and k3 in the storage element 30, the information held in the storage element 30 can be reduced, and It is possible to reduce the capacity,
The cost of the storage element can be reduced.

In this embodiment, the photoconductor calculation coefficient selection information I in the storage element 30 is passed to the photoconductor damage calculation unit 24 for each job, but when the power of the apparatus main body is turned on. May be performed only once.

Fourth Embodiment Next, a fourth 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 this embodiment, as in the second 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, the warning information Y for instructing the user to prepare for replacement because the life of the photoconductor is approaching, and the life information R that is the true life of the photoconductor. Naturally, the magnitude relationship between the two is that the warning information Y <the life information R. The storage element 30 has ten pieces of life selection information J as shown in the information table of FIG.
, And each life selection information J corresponds to the warning information Y and the life information R stored in the comparison unit.

In FIG. 1, the rotation of the photoreceptor 1 is controlled by a photoreceptor rotation instructing unit 25, and the charging roller 2 as a contact charging member is supplied with an AC bias and a DC bias from a primary bias application power supply 12 as appropriate. Are controlled and applied independently by the primary AC voltage output instruction section 21 and the primary DC output instruction section 20.

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 a bias application time detecting unit 23. Application time of application conditions t1, t
2, t3 is detected (S31).

After one job of the printing operation is completed, the application time t1, t2, t3 of each bias application condition and the photoconductor calculation coefficients k1, k2, k3 in the storage element 30 are passed to the photoconductor damage calculation unit 24. (S32). Here, the photoconductor damage calculation unit 24 is connected to the storage element 30 in the drum unit 29. Next, the photoreceptor damage index D is given by the formula D = k1 × t1 + k2 × t2 + k3 × t3.
(Where the above coefficients are k1 = 1, k2 = 0.3, k
3 = 0.1. ) (S33), and the photoconductor damage calculating unit 24 updates the photoconductor damage integrated value S by adding the photoconductor damage index D for one job to the stored photoconductor damage integrated value S (S33). S34). This operation is repeated for each print job.

When one job is completed and the update of the integrated value S stored in the photoconductor damage accumulation storage unit 25 of the storage element 30 is completed, the comparison unit 26 stores the photoconductor life information storage unit 27 of the storage element 30. From the photoconductor life selection information J (S35), and based on the photoconductor life selection information J, the warning information Y and the life information R are selected from the information table shown in FIG. 9 (S36), and the photoconductor damage accumulation storage unit 2
From 5, the updated integrated value S is read, and first, the updated integrated value S is compared with the warning information Y (S37).

As a result of the comparison, when the updated integrated value S is smaller than the warning information Y, the process returns to the normal print sequence, and the life of the photoconductor 1 is not displayed (S38).

On the other hand, if the result of comparing the integrated value S with the warning information Y is S ≧ Y, then the integrated value S is compared with the life information R (S39).

If the result of comparison is that the integrated value S <life information R, the photosensitive member life warning unit (display unit) 28 indicates that the photosensitive member life is approaching, and prompts the user to prepare for replacement. (S40). On the other hand, if the result of the comparison is S ≧ R, a warning unit (display unit) 28 informs the user that the life of the photoconductor has expired, instructs the user to replace the photoconductor, and prints the image. Block operation. When it is confirmed that the photoconductor has been newly replaced, the printing operation is permitted again (S41).

In this embodiment, not the warning information Y and the life information R but the photoconductor life selection information J in the storage element 30.
Thus, the amount of information held in the storage element 30 can be reduced, the capacity of the storage element 30 can be reduced, and the cost of the storage element can be reduced.

In this embodiment, the photoconductor life selection information J in the storage element 30 is compared with the comparison unit 2 for each job.
6 when the power of the main unit was turned on.
It may be performed only once.

Fifth Embodiment In the image forming apparatus of the first to fourth embodiments, the process cartridge including at least the photosensitive drum is made detachable from the apparatus main body, and the storage element is mounted on the process cartridge. In Example 5, as shown in FIG. 10, the storage element 30 is mounted on the apparatus main body without mounting the process cartridge, and the storage element 30 includes, for example, the photosensitive member life information storage unit 27 and the like.

By applying the invention described in Embodiments 1 to 4 to the image forming apparatus of this embodiment, substantially the same functions and effects as in Embodiments 1 to 4 can be obtained. still,
For these descriptions, the descriptions of Examples 1 to 4 are cited.

[0111]

As is apparent from the above description, according to the present invention, when calculating the damage index of the image carrier, the coefficients of the respective application times of the bias application conditions are as follows:
Since the coefficient is stored in the storage means of the process cartridge and can be changed for each process cartridge, the coefficient can be changed for each image carrier or each lot of the image carrier. More appropriate life detection corresponding to the variation of
Since a good image carrier can always be used, it is possible to provide an image carrier life detecting method capable of always obtaining a good image, an image forming apparatus using this method, and a process cartridge detachable from the image forming apparatus. .

[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 mounted on the image forming apparatus of FIG. 1;

FIG. 3 is a diagram illustrating a timing chart of image formation according to the first exemplary embodiment.

FIG. 4 is a flowchart of a photoconductor life detecting process according to the first embodiment.

FIG. 5 is a flowchart of photoconductor life detection according to a second embodiment.

FIG. 6 is a flowchart of photoconductor life detection according to a third embodiment.

FIG. 7 is a coefficient table diagram according to the third embodiment.

FIG. 8 is a flowchart of photoconductor life detection according to a fourth embodiment.

FIG. 9 is a table of a life selection information table according to the fourth embodiment.

FIG. 10 is a schematic configuration diagram illustrating an image forming apparatus according to a fifth embodiment.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 photoconductor (image carrier) 2 charging roller (charging unit) 7 developing device (developing unit) 10 developing sleeve 14 cleaning unit 17 process cartridge 23 bias application time detection unit (detection unit) 24 photoconductor damage calculation unit (calculation unit) 25 photoconductor damage accumulation storage unit (accumulation unit) 26 comparison unit (comparison unit) 28 photoconductor life warning unit (display unit / warning unit / notification unit) 30 storage element (storage unit)

Continuation of front page (56) References JP-A-8-185094 (JP, A) JP-A-8-63053 (JP, A) JP-A-8-179670 (JP, A) JP-A-10-39691 (JP) , A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 21/00 370-540 G03G 21/14 G03G 15/00 303 G03G 15/02-15/02 103 G03G 21/00 350 G03G 21/16-21/18 G03G 15/00 550

Claims (14)

(57) [Claims] 1. A method for detecting the life of an image carrier in an image forming apparatus in which a process cartridge including at least an image carrier is detachable, wherein the process cartridge includes a storage unit and contacts the image carrier to form the image. The voltage applied to the charging means for charging the carrier includes a DC bias component and an AC bias component. During rotation of the image carrier, no bias is applied, only a DC bias is applied, and an AC bias is applied. To n (n ≧ 2) bias application conditions, or no bias application, AC bias application, and application by lowering the AC bias voltage or current value or frequency during rotation of the image carrier. The image forming apparatus has n types (n ≧ 2) of bias application conditions, and the main body of the image forming apparatus has Each of the time t1, t2 ··· tn, coefficient k1, k2 ·
By using kn, the damage index D of the image carrier is calculated as follows: D = k1 × t1 + k2 × t2 +... + Kn × tn (where t1 is the AC bias application time, k1> 0, k2
> 0, k3.gtoreq.0,..., Kn.gtoreq.0), the damage index D of the image carrier is integrated into the image carrier damage integrated value S, and the integrated value S is calculated in advance. By comparing with the determined life information R of the image carrier,
The life of the image carrier is determined, and the coefficient is stored in the storage unit and can be changed for each process cartridge. 2. When the integrated image carrier damage integrated value S is equal to or greater than the image carrier life information R based on a comparison result between the integrated value S and the life information R, 2. The method according to claim 1, wherein the life of the image carrier is warned or displayed. 3. The integrated value S is compared with at least one predetermined warning information Y smaller than the life information R, and the integrated value S is larger than the warning information Y and the life information is compared. 3. The image carrier life detecting method according to claim 2, wherein when the value is smaller than R, the user is urged to replace the process cartridge including the image carrier. 4. The storage means stores life information R and warning information Y. When comparing with the integrated value S by the comparing means, the comparison is performed based on the life information R and the warning information Y. 4. The method according to claim 3, wherein the life of the image carrier is detected. 5. The method according to claim 1, wherein the integrated value is stored in the storage unit. 6. An image forming apparatus in which a process cartridge including at least an image carrier is detachable, wherein the process cartridge includes a storage unit, and a charging unit that contacts the image carrier and charges the image carrier is applied. The voltage to be applied includes a DC bias component and an AC bias component, and during rotation of the image carrier, n types (n ≧ 2) of three of the following three types: no bias application, only DC bias application, and AC bias application N kinds (n ≧ 2) of the following three conditions: bias application condition, no bias application, AC bias application, and voltage / current value or frequency of this AC bias applied during rotation of the image carrier. , T2, t2,... T
n and the coefficients k1, k2,... kn, the damage index D of the image carrier is calculated as follows: D = k1 × t1 + k2 × t2 +. , K2
> 0, k3 ≧ 0,..., Kn ≧ 0), an integrating means for integrating the damage index D of the image carrier into an integrated value of the image carrier damage, and an integrating means. A means for comparing the integrated value with life information indicating a predetermined life of the image carrier; and an image carrier damage integrated value integrated by the integrating means based on a result of the comparing means. Warning means or notifying means for warning or displaying the life of the image carrier when the life is equal to or longer than the life information, wherein the coefficient is stored in the storage means and can be changed for each process cartridge An image forming apparatus comprising: 7. A warning information, which is smaller than at least one or more predetermined life information, and prompts the user to prepare for replacement of the image carrier before the image carrier reaches the end of its life. A comparing means for comparing the integrated value with the image carrier damage value, based on the result of the comparing means, when the integrated value integrated by the integrating means is equal to or greater than predetermined warning information, Means for warning or displaying replacement preparation and warning or displaying the life of the image carrier when the integrated value integrated by the integrating means based on the result of the comparing means is equal to or longer than predetermined life information. 7. The image forming apparatus according to claim 6, wherein when the life of the image carrier is warned or displayed by the warning unit or the display unit, the image forming operation of the image forming apparatus main body is stopped. Forming equipment. 8. Writing the integrated value into the storage means,
8. The image forming apparatus according to claim 6, further comprising a reading unit. 9. The storage means stores life information R and warning information Y. When comparing with the integrated value by the comparing means, the comparison is performed based on the life information R and the warning information Y. 9. The image forming apparatus according to claim 6, wherein: 10. The image forming apparatus according to claim 6, wherein the integrated value is stored in the storage unit. 11. A process cartridge detachably mountable to an image forming apparatus main body, comprising: an image carrier; and a process unit having at least charging means for charging the image carrier by contacting the image carrier;
And a voltage applied to the charging means,
A DC bias component and an AC bias component are included, and no bias is applied during rotation of the image carrier.
Apply only bias and apply AC bias n
There are three types of bias application conditions (n ≧ 2), or no application of bias, application of AC bias, and application of this AC bias by lowering the voltage value or current value or frequency during rotation of the image carrier. The image forming apparatus main body has n types (n ≧ 2) of bias application conditions, and the image forming apparatus main body has respective times t1, t2,.
Using k,... Kn, the damage index D of the image carrier is calculated as follows: D = k1 × t1 + k2 × t2 +... + Kn × tn (where t1 is the AC bias application time, k1> 0, k2
> 0, k3 ≧ 0,..., Kn ≧ 0), integrating means for integrating the damage index D of the image carrier into an integrated value of image carrier damage, and integrating means. Means for comparing the integrated value with a predetermined life information of the image carrier, and an image carrier damage integrated value integrated by the integrating means based on the result of the comparing means. Warning means or notifying means for warning or displaying the life of the image carrier when the life information is longer than the life information, wherein the coefficient is stored in the storage means and can be changed for each process cartridge A process cartridge. 12. The image forming apparatus main body according to claim 1, wherein the warning is smaller than at least one or more of the predetermined lifetime information in order to prompt the user to prepare for replacement of the image carrier before the image carrier reaches the end of its life. Information, and comparing means for comparing the life information with the integrated value of the image carrier damage. Based on the result of the comparing means, the integrated value integrated by the integrating means is equal to or larger than predetermined warning information. At one time, warning or display of the preparation for replacing the image carrier is issued or displayed, and when the integrated value integrated by the integrating means based on the result of the comparing means is longer than predetermined life information, the life of the image carrier is Means for warning or displaying a warning. When the warning means or the display means warns or displays the life of the image bearing member, the image forming operation of the image forming apparatus main body is stopped. The process cartridge according to claim 11, wherein: 13. The process cartridge according to claim 11, wherein the image forming apparatus main body includes a unit that writes or reads the integrated value to or from the storage unit. 14. The process cartridge according to claim 11, wherein the integrated value is stored in the storage unit.