JP2003195700A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus of which the maintenance cost is reduced and which forms an excellent image by judging the accurate life of a conductive member and suitably replacing the conductive member. <P>SOLUTION: The image forming apparatus is provided with a life judging program for judging the life of a transfer roller 27 on the basis of a voltage value En detected by a voltmeter 72, of the roller 27 to which transfer bias is applied and temperature T and humidity H detected by a temperature/humidity sensor 73. In the life judging program, the life of the roller 27 is judged by making the detected voltage value En, temperature T and humidity H correspond to each other. Since the life of the roller 27 has expired or not is judged in consideration of the variation of the detected voltage value En, temperature T and humidity H, accurate life can be judged. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a laser printer.

[0002]

2. Description of the Related Art In an image forming apparatus such as a laser printer, a developing roller carrying toner, a photosensitive drum on which an electrostatic latent image is formed, and a transfer roller for transferring a visible image onto paper are usually used. A cleaning roller is provided for collecting the toner remaining on the photosensitive drum after the transfer.

In such an image forming apparatus, the toner carried on the developing roller is selectively supplied to the electrostatic latent image formed on the photosensitive drum to develop the electrostatic latent image, As a result, a visible image is formed on the photosensitive drum, and when the visible image faces the sheet passing between the photosensitive drum and the transfer roller due to the rotation of the photosensitive drum, the transfer bias applied to the transfer roller. Is transferred to a sheet, and a predetermined image is formed on the sheet. After that, the toner remaining on the photosensitive drum is collected by the cleaning roller.

In such an image forming apparatus, during image formation, for example, the transfer roller is always
Since the transfer bias is applied, the resistance value of the transfer roller increases irreversibly. Then, if the resistance value of the transfer roller rises too much, even if the set transfer bias is applied, a transfer failure occurs and an image cannot be formed satisfactorily.

Therefore, for example, during long-term use, the resistance value of the transfer roller is measured, and if the measured resistance value is out of a predetermined allowable range, it is determined that the transfer roller has reached the end of its life. Various warnings such as replacing the transfer roller have been proposed.

[0006]

However, since the resistance value of the transfer roller changes depending on the environment such as temperature and humidity at the time of measurement, the resistance value of the transfer roller is simply measured and the measured value of the transfer roller is measured. If the life of the transfer roller is judged uniformly, the accurate life of the transfer roller cannot be judged.Therefore, it is necessary to replace the transfer roller whose life is not actually longer, resulting in unnecessary maintenance cost, or the life of the transfer roller is actually shorter. When a certain transfer roller is continuously used as it is, a defect such as a transfer failure may occur.

Therefore, the present invention has been made in view of such a problem, and an object of the present invention is to reduce the maintenance cost by judging the accurate life of the conductive member and appropriately replacing the conductive member. An object of the present invention is to provide an image forming apparatus capable of achieving high quality and excellent image formation.

[0008]

In order to achieve the above object, the invention according to claim 1 is an image forming apparatus including a conductive member to which a bias is applied during image formation, and detects the electrical characteristic of the conductive member. Based on the electrical characteristics of the conductive member sensed by the electrical characteristics sensing means, the environment sensing means for sensing the environment, the electrical characteristics of the conductive member, the environment sensed by the environment sensing means, The present invention is characterized in that a life determining means for determining the life of the conductive member is provided.

According to this structure, the electric characteristic detecting means detects the electric characteristic of the conductive member, the environment detecting means detects the environment at the time of detecting the electric characteristic of the conductive member, and the life judging means detects the environment. The electrical characteristics and environment are associated with each other to determine the life of the conductive member. Therefore, whether or not the conductive member has reached the end of its life can be determined in consideration of environmental fluctuations in the detected electrical characteristics, and therefore the life can be accurately determined. Therefore, by appropriately replacing the conductive member, it is possible to reduce the maintenance cost and achieve good image formation.

The invention described in claim 2 is the same as claim 1.
In the invention described in (1), the life determining means is an environment,
It has a life table in which the reference value of the electrical characteristics to be judged as the life is associated with, by the life table, the reference value of the electrical characteristics corresponding to the detected environment is specified, and the detected electrical characteristics and It is characterized in that the life of the conductive member is determined by comparison.

According to this structure, by comparing the detected electrical characteristic with the specific reference value of the electrical characteristic corresponding to the detected environment by the life table.
The life of the conductive member can be determined easily and reliably. Therefore, the conductive member can be replaced more appropriately.

The invention described in claim 3 is the same as claim 1
Alternatively, in the invention described in 2, the environment detecting means is
It is characterized by detecting temperature and / or humidity.

With such a configuration, the detected electrical characteristics are associated with the temperature and / or humidity at the time of detection to determine the life of the conductive member, so that the life of the conductive member is more reliably achieved. Can be judged.

The invention described in claim 4 is the same as that of claim 2
Or in the invention described in 3, the life table is
It is characterized in that reference values of electric characteristics are associated with each other so as to be specified based on temperature and humidity.

According to this structure, the reference value of the electric characteristic is specified in accordance with the temperature and the humidity at the time of detecting the electric characteristic, and the specified reference value is compared with the detected electric characteristic. As a result, the life of the conductive member is determined, so that the life of the conductive member can be determined more accurately, and the conductive member can be replaced more appropriately.

According to a fifth aspect of the invention, in an image forming apparatus including a conductive member to which a bias is applied during image formation, a total power amount detection for detecting the total power amount applied to the conductive member. And a life judging means for judging the life of the conductive member based on the total electric energy detected by the total electric energy detecting means.

According to this structure, the life determining means determines the life of the conductive member based on the total amount of electric power detected by the total amount of electric power detecting means, so that the total amount of electric power already includes environmental factors. Therefore, the life can be accurately determined without separately detecting the environment. Therefore, by appropriately replacing the conductive member, it is possible to reduce the maintenance cost and achieve good image formation.

The invention described in claim 6 is the same as claim 5
In the invention described in (1), the total electric power amount detecting means is an electric characteristic detecting means for detecting an electric characteristic of the conductive member, and an electric power calculating means for calculating electric power based on the electric characteristic detected by the electric characteristic detecting means. And a total power amount calculating unit for calculating the total power amount based on the power calculated by the power calculating unit and the bias application time.

According to this structure, the electric power calculating means calculates electric power based on the electric characteristic of the conductive member detected by the electric characteristic detecting means, and the total electric power is calculated based on the electric power and the bias application time. Since the amount calculation means calculates the total amount of electric power, the total amount of electric power can be calculated more easily and efficiently. Therefore, it is possible to further reduce the maintenance cost and achieve good image formation by appropriately exchanging the conductive member.

The invention according to claim 7 provides the invention according to claim 6.
In the invention described in (3), the total electric power amount calculating means is characterized in that the bias applying time is calculated by converting the number of contact mediums in contact with the conductive member.

According to this structure, the total electric power amount calculating means converts the number of contact mediums in contact with the conductive member,
Since the time during which the bias is applied is calculated, simplification and efficiency of the calculation for calculating the total power amount are achieved,
It is possible to calculate an almost accurate total electric energy.

The invention according to claim 8 is characterized in that the electric characteristic detecting means detects the electric characteristic when the contact medium is in contact.

According to this structure, the electrical characteristics in a state suitable for the actual usage can be detected, so that the life of the conductive member can be determined more in accordance with the actual usage.

The invention described in claim 9 is the same as claim 5
In the invention described in any one of (1) to (8), the total power calculation means calculates a power amount for each predetermined unit and accumulates the calculated power amount.

According to this structure, the amount of electric power is calculated for each job at the time of image formation or for each page, so that the calculation for calculating the total amount of electric power can be simplified and made more efficient. Therefore, it is possible to achieve a simple and efficient calculation of the total amount of electric power.

According to a tenth aspect of the present invention, in an image forming apparatus including a conductive member to which a bias is applied during image formation, an electric characteristic detecting unit for detecting an electric characteristic of the conductive member, and the conductive member. A reference conductive member that has the same physical properties as the member, is placed under the same environment, and to which a bias is not applied during image formation; reference electrical characteristic detection means for detecting the electrical characteristic of the reference conductive member; Life judgment for judging the life of the conductive member by comparing the electric characteristic of the conductive member detected by the characteristic detecting means and the electric characteristic of the reference conductive member detected by the reference electric characteristic detecting means. It is characterized by having means.

According to this structure, the life of the conductive member used for image formation is judged by relative comparison with the reference conductive member not used for image formation. The reference conductive member receives the same environmental history as the conductive member except that the bias is not applied during image formation, so the life of the conductive member can be determined in accordance with the actual environmental changes, and the accuracy can be improved. It is possible to accurately and accurately determine the service life. Therefore, by appropriately replacing the conductive member, it is possible to reduce the maintenance cost and achieve good image formation.

According to an eleventh aspect of the present invention, in the tenth aspect of the invention, the reference conductive member is always separated from a contact member with which the conductive member is in contact when a bias is applied. A contact / separation mechanism is provided for making contact when the reference electric characteristic detecting means detects the electric characteristic.

According to this structure, when the reference electric characteristic detecting means detects the electric characteristic, the reference conductive member is brought into contact with the contact member by the contact / separation mechanism. The characteristics and are detected under the same conditions. Therefore, it is possible to achieve more accurate determination of the life of the conductive member by accurate relative comparison. Further, since the reference conductive member is separated from the contact member by the contacting / separating mechanism except when the electric characteristics are detected, an electrical load from the contact member is not always applied, and the reference conductive member serves as a reference for the conductive member. It is kept in good condition. Therefore, the life of the conductive member can be more accurately determined.

According to a twelfth aspect of the present invention, in the invention according to any one of the first to fourth and sixth to eleventh aspects, the electrical characteristic is at least one of a current value, a voltage value and a resistance value. It is characterized by being.

According to this structure, it is possible to easily and surely determine the life of the conductive member by detecting at least one of the current value, the voltage value and the resistance value.

According to a thirteenth aspect of the present invention, in the invention according to the twelfth aspect, a bias is applied to the conductive member with a constant current, and the electrical characteristic detecting means detects a voltage value. It has a feature.

According to this structure, the bias applied to the conductive member is controlled with a constant current, and the voltage value generated from the conductive member is detected by the voltmeter, so that the electric characteristics can be detected easily and reliably. be able to. Therefore, the life of the conductive member can be more accurately determined, and the conductive member can be replaced more appropriately.

According to a fourteenth aspect of the invention, in the invention of the twelfth aspect, a bias is applied to the conductive member at a constant voltage, and the electrical characteristic detecting means detects a current value. It has a feature.

According to this structure, the bias applied to the conductive member is controlled to a constant voltage, and the current value generated from the conductive member is detected by the ammeter, so that the electric characteristics can be detected easily and reliably. be able to. Therefore, the life of the conductive member can be more accurately determined, and the conductive member can be replaced more appropriately.

Further, the invention according to claim 15 is the invention according to any one of claims 1 to 14, characterized in that the conductive member is an ion conductive member.

When the conductive member is an ion conductive member, the resistance value changes remarkably depending on the environment. With such a structure, it is possible to accurately determine the life of the conductive member. With proper replacement, good image formation can always be achieved.

According to a sixteenth aspect of the present invention, in the invention according to any one of the first to fifteenth aspects, the conductive member is arranged so as to face the image carrier on which an electrostatic latent image is formed. Any one of a member, a developing member, a transfer member, and a cleaning member, characterized in that the image carrier is used when detecting the electrical characteristics of the conductive member.

According to this structure, the conductive member is any one of the charging member, the developing member, the transfer member, and the cleaning member, which are arranged to face the image carrier, and when the electric characteristics of them are detected, the image carrier is carried. Since the body is used, it is possible to detect the electrical characteristics in a state in which the body is actually used, and it is possible to more reliably determine the life of the conductive member.

According to a seventeenth aspect of the present invention, in the invention according to the sixteenth aspect, the transfer member electrically forms a developer image formed by developing the electrostatic latent image of the image carrier. It is characterized in that it is an image transfer member that sucks.

When the transfer member is an image transfer member which electrically attracts the developer image formed by developing the electrostatic latent image on the image carrier, a large transfer bias is applied,
In particular, the resistance value is largely increased due to the durability, and the transfer failure is likely to occur.

However, with this configuration, it is possible to accurately determine the life of the image transfer member and to more appropriately replace the image transfer member. Image formation can be achieved.

The invention described in claim 18 is the invention described in claim 16 or 17, characterized in that the transfer member is a transfer roller.

When the transfer member is a transfer roller, a large transfer bias is applied, so that the resistance value is greatly increased due to the durability, and the transfer failure is likely to occur.

However, with this configuration, it is possible to accurately determine the life of the transfer roller and to more appropriately replace the transfer roller, so that good transfer is always ensured and a good image is obtained. Formation can be achieved.

The invention described in claim 19 is the invention described in claim 16 or 17, characterized in that the transfer member is a transfer belt.

When the transfer member is a transfer belt, a large transfer bias is applied, so that the resistance value is greatly increased due to the durability and the transfer failure is likely to occur.

However, with this structure, it is possible to accurately determine the life of the transfer belt and to more appropriately replace the transfer belt. Therefore, good transfer is always ensured and a good image is obtained. Formation can be achieved.

According to a twentieth aspect of the present invention, in the invention according to any one of the first to nineteenth aspects, when the life determining means determines that the conductive member has reached the end of its life, It is characterized in that it is provided with a notifying means for notifying the arrival.

According to this structure, when it is determined that the conductive member has reached the end of its life, the notification means informs the user that the life of the conductive member has reached its end of life. It is possible to easily recognize the fact and replace the conductive member appropriately. Therefore, it is possible to further reduce the maintenance cost and achieve good image formation by appropriately exchanging the conductive member.

[0051]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a side sectional view of an essential part showing an embodiment of a laser printer as an image forming apparatus of the present invention. In FIG. 1, the laser printer 1 is configured as a laser printer that forms an image by an electrophotographic method, and a main body casing 2 is provided with a feeder unit 4 for feeding a sheet 3 as a contact medium and a feeding unit. An image forming unit 5 for forming a predetermined image on the printed paper 3 is provided.

The feeder unit 4 includes a paper feed tray 6 which is removably mounted on the bottom of the main body casing 2, a paper feed mechanism unit 7 provided at one end of the paper feed tray 6, and a paper feed tray. A paper pressing plate 8 provided inside 6 and a downstream side of the paper feed mechanism unit 7 in the conveyance direction of the paper 3 (hereinafter, the upstream side or the downstream side of the paper 3 in the conveyance direction is simply referred to as the upstream side or the downstream side). In some cases.), The first transport unit 9 and the second transport unit 10, and the registration roller 11 and the registration roller provided downstream of the first transport unit 9 and the second transport unit 10 in the transport direction of the sheet 3. And a sensor 70.

The paper feed tray 6 has a box shape with an open upper surface capable of accommodating the paper 3, and is attachable to and detachable from the bottom of the main body casing 2 in the horizontal direction.

The paper feed mechanism section 7 includes a paper feed roller 12 and a separation pad 13 facing the paper feed roller 12, and the separation pad 13 is pressed by a spring from the back side of the paper feed roller 12 to supply the paper. It is pressed against the paper roller 12.

The sheet pressing plate 8 is capable of stacking the sheets 3 in a stack, and is swingably supported at the end portion far from the sheet feeding roller 12, so that the near end portion is vertically moved. It is movable in any direction, and is biased upward from the back side by a spring (not shown). Therefore, as the stacking amount of the sheets 3 increases, the sheet pressing plate 8 uses the end farthest from the sheet feeding mechanism section 7 as a fulcrum,
It swings downward against the biasing force of the spring.

Then, the uppermost sheet 3 on the sheet pressing plate 8 is pressed from the back side of the sheet pressing plate 8 toward the sheet feeding roller 12 by a spring (not shown), and is fed by the rotation of the sheet feeding roller 12. After being sandwiched by the roller 12 and the separating pad 13, the sheets are separated and fed one by one by their cooperation.

The first conveying section 9 is arranged on the downstream side of the sheet feeding mechanism section 7, is arranged so as to face the first conveying roller 9a for conveying the sheet 3 and the first conveying roller 9a. First paper dust removing roller 9b formed slightly wider
And a first sponge member 9c that is disposed below and under the first paper dust removing roller 9b. Then, the fed paper 3 is conveyed while being sandwiched between the first conveyance roller 9a and the first paper dust removing roller 9b, and at that time, the paper generated on the paper 3 due to the friction between the separation pad 13 and the paper. The dust is scraped off by the first paper dust removing roller 9b.
The paper dust attached to the first paper dust removing roller 9b is
It is scraped off by the sponge member 9c.

The second carrying section 10 is arranged downstream of the first carrying section 9 and carries the second carrying roller 1 carrying the paper 3.
0a and the second transport roller 10a are arranged to face each other, and the paper 3
Second paper dust removing roller 1 formed slightly wider than the width of
0b and a second sponge member 10c that is disposed below the second paper dust removing roller 10b so as to face each other. Then, the sheet 3 conveyed from the first conveying section 9
Is the second transport roller 10a and the second paper dust removing roller 10b.
The second paper dust removing roller 10b scrapes away paper dust originally generated on the entire paper 3 at the time of cutting the paper 3 and the like. In addition,
The paper dust attached to the second paper dust removing roller 10b is scraped off by the second sponge member 10c.

The registration roller 11 is composed of a pair of rollers, and is configured to send the sheet 3 to the image forming section 5 after a predetermined registration. Therefore, the first transport unit 9
The paper 3 from which the paper dust generated by the rubbing with the separation pad 13 and the paper dust originally generated by the second transport unit 10 are removed in a well-balanced manner is the second transport unit 1.
After being sent from the registration roller 11 to the registration roller 11, the registration roller 11 conveys the image to the image forming unit 5 after a predetermined registration.

The registration sensor 70 is the registration roller 1
1, the sensor is turned on to detect the arrival of the leading edge of the sheet 3, and the sensor is turned off to detect the passage of the trailing edge of the sheet 3. The signal is input to the CPU 74 described later. In addition,
In the CPU 74, in the control described later, the image forming unit 5 is set by turning the registration sensor 70 on and off.
Whether or not the image forming process on the sheet 3 is completed by counting the number of sheets 3 conveyed to the sheet and measuring a predetermined time from the time when the registration sensor 70 is turned on to off (that is, It is determined whether or not the trailing edge of the sheet 3 has passed a contact portion between the photosensitive drum 25 and the transfer roller 27, which will be described later.

Further, the feeder section 4 of the laser printer 1 further feeds the multi-purpose tray 14 on which the sheets 3 of an arbitrary size are stacked and the sheet 3 stacked on the multi-purpose tray 14. The multi-purpose paper feed mechanism unit 15 and the multi-purpose transport unit 16 are provided.

The multi-purpose paper feeding mechanism section 15 includes a multi-purpose paper feeding roller 15a and a multi-purpose separating pad 15 opposed to the multi-purpose paper feeding roller 15a.
b and a multi-purpose separation pad 15b
Is pressed by a spring from its back side,
It is pressed toward the multi-purpose paper feed roller 15a. The uppermost sheet 3 stacked on the multi-purpose tray 14 is the multi-purpose sheet feeding roller 15a.
After being nipped by the multi-purpose paper feed roller 15a and the multi-purpose separation pad 15b, the sheets are separated and fed one by one by their cooperation.

The multi-purpose carrying section 16 is arranged on the downstream side of the multi-purpose paper feeding mechanism section 15 and on the upstream side of the registration rollers 11, and a multi-purpose carrying roller 16a for carrying the sheet 3 is provided. The multi-purpose paper dust removing roller 16b is arranged to face the multi-purpose conveying roller 16a, and the multi-purpose sponge member 16c is arranged to face below the multi-purpose paper dust removing roller 16b. Then, the paper 3 fed from the multi-purpose paper feed mechanism unit 15 is conveyed while being sandwiched between the multi-purpose conveyance roller 16a and the multi-purpose paper dust removing roller 16b, and at that time, the paper dust on the paper 3 is multi-plied. It is scraped off by the purpose paper dust removing roller 16b. In addition, multi-purpose paper dust removing roller 1
The paper powder attached to 6b is the multipurpose sponge member 1
It is scraped off by 6c.

Then, the paper 3 from which the paper dust has been removed by the multi-purpose carrying section 16 has the multi-purpose carrying section 1
6 is sent to the registration roller 11 and the registration roller 1
After a predetermined resist from 1 is carried to the image forming section 5.

The image forming section 5 comprises a scanner section 17, a process section 18, a fixing section 19 and the like.

The scanner unit 17 is provided in the upper portion of the main body casing 2, and includes a laser emitting unit (not shown), a polygon mirror 20 that is driven to rotate, and lenses 21a and 21.
b, a reflecting mirror 22 and the like, and emits a laser beam based on predetermined image data emitted from the laser emitting section,
As indicated by the chain line, the polygon mirror 20 and the lens 21
A, the reflecting mirror 22, and the lens 21b are passed or reflected in this order, and the surface of the photosensitive drum 25 of the process unit 18 described later is irradiated with high-speed scanning.

The process section 18 is disposed below the scanner section 17, and is provided inside the drum cartridge 23 which is detachably attached to the main body casing 2, and the developing cartridge 24 and a contact member serving as an image carrier. Photosensitive drum 25, a charging roller 26 as a charging member, and a transfer roller 2 as an electrically conductive member that is an image transfer member (transfer member).
7 and 7.

The developing cartridge 24 is detachably attached to the drum cartridge 23, and is provided with a toner accommodating portion 30, a supply roller 31, a layer thickness regulating blade 32, a developing roller 33 as a developing member, and the like.

In the toner containing portion 30, as a developer,
It is filled with positively chargeable non-magnetic one-component toner. Examples of the toner include a polymerizable monomer, for example, a styrene-based monomer such as styrene, acrylic acid, alkyl (C
Polymerized toners obtained by copolymerizing acrylic monomers such as 1-C4) acrylates and alkyl (C1-C4) methacrylates by a known polymerization method such as suspension polymerization are used. Since such a polymerized toner has a spherical shape and has extremely good fluidity, good development can be achieved, and as a result, a high quality image can be formed. In addition to such a toner, a coloring agent such as carbon black and a wax are mixed, and an external additive such as silica is added in order to improve fluidity. The average particle size is about 6
It is about 10 μm.

Then, the toner in the toner container 30 is
The toner is discharged from the toner storage unit 30 toward the supply roller 31 by an agitator (not shown).

A supply roller 31 is rotatably arranged at a side position of the toner containing portion 30, and a developing roller 33 is rotatably arranged so as to face the supply roller 31. . The supply roller 31 and the developing roller 33 are in contact with each other in such a state that they are compressed to some extent.

The supply roller 31 has a metal roller shaft,
A roller made of a conductive sponge body is covered.

The developing roller 33 has a metal roller shaft,
A roller made of an elastic material which is a conductive rubber material is covered. More specifically, in the roller of the developing roller 33, the surface of a roller body made of conductive urethane rubber or silicone rubber containing carbon fine particles or the like is coated with a coating layer of fluorine-containing urethane rubber or silicone rubber. Has been done. The developing roller 33
A predetermined developing bias is applied by a developing bias applying circuit 84 (see FIG. 4) described later.

Further, a layer thickness regulating blade 32 is arranged near the developing roller 33. The layer thickness regulating blade 32 is disposed above the developing roller 33 so as to face each other along the axial direction of the developing roller 33, and is provided on the leaf spring member attached to the developing cartridge 24 and the tip portion of the leaf spring member. A pressing member having a semicircular cross section made of insulating silicone rubber is provided, and the pressing member is configured to be pressed against the developing roller 33 by the elastic force of the leaf spring member.

The toner discharged from the toner storage chamber 30 is rotated by the supply roller 31 to cause the developing roller 3 to rotate.
3 is supplied to the developing roller 3 at this time.
3 is positively triboelectrically charged, and further, the developing roller 33
The toner supplied onto the developing roller 33 and the pressing member of the layer thickness regulating blade 32 are rotated by the rotation of the developing roller 33.
Between and where it is more tribocharged,
It is carried on the developing roller 33 as a thin layer having a constant thickness.

The photosensitive drum 25 is rotatably arranged at a position lateral to the developing roller 33 so as to face the developing roller 33. This photosensitive drum 25
The drum main body is grounded, and the surface portion thereof is formed of a positively chargeable photosensitive layer made of polycarbonate or the like.

The charging roller 26 is disposed above the photosensitive drum 25 so as to be in contact with the photosensitive drum 25.
In the charging roller 26, a conductive metal core connected to a high voltage power supply 79 (see FIG. 4) is coated with a conductive rubber or a semiconductive material as a charge supply layer, and a charging circuit 83 (see FIG. 4), the surface of the photosensitive drum 25 is uniformly charged to the positive polarity.

The surface of the photosensitive drum 25 is first charged by the charging roller 26 as the photosensitive drum 25 rotates.
After being uniformly positively charged by, the laser beam from the scanner unit 17 is exposed by high-speed scanning to form an electrostatic latent image based on predetermined image data.

Next, when the toner carried on the developing roller 33 and positively charged comes into contact with the photosensitive drum 25 so as to face the photosensitive drum 25 by the rotation of the developing roller 33, a static charge is formed on the surface of the photosensitive drum 25. An electrostatic latent image, that is, a surface of the photosensitive drum 25 that is uniformly positively charged, is supplied to an exposed portion of the surface of the photosensitive drum 25 that is exposed by a laser beam and has a reduced potential, and is selectively carried to form a visible image. And thus reversal development is achieved.

The transfer roller 27 is arranged below the photosensitive drum 25 so as to face the photosensitive drum 25, and is rotatably supported by the drum cartridge 23. The transfer roller 27 is a metallic roller shaft 2.
7a (see FIG. 2) is covered with a roller 27b (see FIG. 2) made of an ion conductive rubber material. And
At the time of transfer, a high voltage constant current power supply 71 (see FIG. 4) described later.
Is configured so that a transfer bias of constant current is applied. Therefore, in the visible image carried on the surface of the photosensitive drum 27, the paper 3 is the photosensitive drum 25 and the transfer roller 2
It is transferred to the sheet 3 while passing between the sheet 7 and the sheet 7. Then, the sheet 3 to which the visible image is transferred is conveyed to the fixing unit 19 via the conveyance belt 45.

Further, the process section 18 further includes
A cleaning unit 40 for cleaning the surface of the photosensitive drum 25 after transfer is provided in the drum cartridge 23. The cleaning unit 40 is disposed on the opposite side of the developing roller 33 with respect to the photosensitive drum 25, on the downstream side of the transfer roller 27 and on the upstream side of the charging roller 26 in the rotation direction of the photosensitive drum 25, and serves as a cleaning member. The cleaning roller 41, the backup roller 42, the scraping sponge 43, and the collecting and storing section 44 are provided.

The cleaning roller 41 is the photosensitive drum 2
5 is made of foamed elastic material such as silicone rubber, and a predetermined cleaning bias is applied to the photosensitive drum by a cleaning bias application circuit 85 (see FIG. 4) described later.

The backup roller 42 is provided on the opposite side of the cleaning roller 41 from the photosensitive drum 25.
The cleaning roller 41 is arranged so as to be in contact with the cleaning roller 41, is made of a metal roller, and a predetermined cleaning bias is applied to the cleaning roller 41 by a cleaning bias application circuit 85 (see FIG. 4) described later.

The scraping sponge 43 is arranged on the opposite side of the backup roller 42 from the cleaning roller 41 so as to be in pressure contact with the surface of the backup roller 42. The scraping sponge 43 is made of a sponge member such as urethane foam, and is configured to scrape off the toner and paper dust attached to the surface of the backup roller 42.

The collecting and storing section 44 is provided in the drum cartridge 2
3 is formed as a space below the scraping sponge 43, and the toner and the paper powder scraped by the scraping sponge 43 are stored in the collecting and storing section 44.

After the transfer onto the sheet 3, the photosensitive drum 2
The toner and paper dust remaining on the sheet 5 are electrically captured by the cleaning roller 41 when the surface of the photosensitive drum 25 faces the cleaning roller 41. After that, the captured toner and paper dust are electrically captured by the backup roller 42 when the cleaning roller 41 rotates and face the backup roller 42, and are then scraped off by the scraping sponge 43 and collected. It is stored in the storage unit 44.

The fixing section 19 is arranged on the downstream side of the process section 18, and is provided on the heating roller 46, the pressing roller 47 for pressing the heating roller 46, and the downstream side of the heating roller 46 and the pressing roller 47. Transport roller 4
Eight.

The heating roller 46 is made of metal and is provided with a halogen lamp for heating. The paper 3 heats the toner transferred onto the paper 3 in the process section 18.
6 is fixed by heat while passing between 6 and the pressing roller 47,
After that, the sheet 3 is conveyed by the conveying roller 48 of the fixing unit 19 to the conveying roller 49 and the sheet discharging roller 50 provided in the main body casing 2. The sheet 3 sent to the transport roller 49 is then discharged from the discharge roller 50.
Then, the sheet is discharged onto the sheet discharge tray 51.

The fixing section 19 includes a heating roller 46 and a pressing roller 47 in the sheet 3 conveying direction,
A paper passage sensor 60 for setting a switching timing of a reversing roller 57, which will be described later, between the conveyance roller 48 and
Is provided.

Further, the laser printer 1 is provided with a paper 3
Re-conveying unit 52 for forming images on both sides of The re-conveying unit 52 includes a reversing mechanism section 53.
And the re-conveying tray 54 are integrally configured, and the re-conveying tray 54 is inserted above the feeder section 4 while the reversing mechanism section 53 is externally attached from the rear side of the main body casing 2. In this state, it is detachably attached.

The reversing mechanism portion 53 is externally attached to the rear wall of the main body casing 2, and has a flapper 56, a reversing roller 57 and a re-conveying roller 58 in a casing 55 having a substantially rectangular cross section, and a reversing guide from the upper end portion. Plate 59
Is projected upward.

The flapper 56 is rotatably supported on the rear portion of the main body casing 2, is arranged in the vicinity of the downstream side of the conveying roller 48, and an image is formed on one surface by exciting or de-exciting a solenoid (not shown). The sheet 3 conveyed by the conveyance roller 48 is conveyed by the conveyance roller 4
9 (solid line state) and a direction (represented by imaginary line) toward the reversing roller 57, which will be described later, are swingably provided.

The reversing roller 57 is arranged on the downstream side of the flapper 56 and above the casing 55, and is composed of a pair of rollers, and is configured so that the rotation can be switched between the forward direction and the reverse direction. This reversing roller 57
First, the sheet 3 is rotated in the forward direction so that the sheet 3 is reversed to the guide plate
9 and then rotate in the opposite direction to feed paper 3
Can be conveyed in the reverse direction.

The re-conveying roller 58 is on the downstream side of the reversing roller 57, and is the reversing roller 57 in the casing 55.
The re-transport tray 5 is provided with a pair of rollers, which is disposed immediately below the sheet 3 and is reversed by the reversing roller 57.
4 is configured so that it can be transported.

The reversing guide plate 59 is made of a plate-like member extending further upward from the upper end of the casing 55, and the sheet 3 fed by the reversing roller 57.
Is configured to guide.

When images are to be formed on both sides of the sheet 3, the flapper 56 is first switched in the reversing mechanism section 53 so as to direct the sheet 3 to the reversing roller 57, and the reversing mechanism section 53 is turned on. Then, the sheet 3 having the image formed on one surface is received. After that, when the accepted sheet 3 is sent to the reversing roller 57,
The reversing roller 57 rotates forward with the paper 3 being sandwiched,
The sheet 3 is once conveyed upward and outward along the reverse guide plate 59, and most of the sheet 3 is sent upward and upward, and when the rear end of the sheet 3 is nipped by the reverse roller 57,
Stop forward rotation. Next, the reversing roller 57 rotates in the reverse direction, and conveys the sheet 3 to the re-conveying roller 58 in a state in which the sheet 3 is reversed in the front-rear direction so as to face substantially right below. The timing for rotating the reversing roller 57 from the forward rotation to the reverse rotation is
Paper passage sensor 60 provided on the downstream side of the fixing unit 19
However, it is controlled so that a predetermined time elapses after the trailing edge of the sheet 3 is detected. In addition, flapper 56
When the conveyance of the sheet 3 to the reversing roller 57 is completed, the original state, that is, the sheet 3 sent from the conveying roller 48 is sent.
Is switched to a state where it is sent to the conveyance roller 49.

Next, the sheet 3 conveyed in the opposite direction to the re-conveyance roller 58 is re-conveyed by the re-conveyance roller 58.
It is transported to the re-transport tray 54 described below.

The re-conveyance tray 54 includes a sheet supply section 61 to which the sheet 3 is supplied, a tray body 62 and a skew roller 63.
Is equipped with.

The sheet feeding section 61 is externally attached to the rear portion of the main body casing 2 below the reversing mechanism section 53, and is provided with a curved sheet guiding member 64. This paper supply unit 6
In 1, the sheet 3 fed in the substantially vertical direction from the re-conveying roller 58 of the reversing mechanism section 53 is guided in the substantially horizontal direction by the sheet guide member 64 and is moved in the substantially horizontal direction toward the tray body 62. I try to send it out.

The tray main body 62 has a substantially rectangular plate shape and is provided above the paper feed tray 6 in a substantially horizontal direction. The upstream end of the tray main body 62 is connected to the paper guide member 64, and The downstream end is the second from the tray main body 62.
It is connected to a re-conveyance path 65 for guiding the sheet 3 to the conveyance section 10.

In the middle of the tray main body 62 in the conveyance direction of the paper 3, a skew roller 63 for conveying the paper 3 while abutting against a reference plate (not shown) is provided at a predetermined interval in the conveyance direction of the paper 3. Are separated by two.

Each of the skew rollers 63 is disposed in the vicinity of a reference plate (not shown) provided at one end of the tray body 62 in the width direction, and the skew line is arranged in a direction whose axis is substantially orthogonal to the conveying direction of the sheet 3. The drive roller 66 and the skew drive roller 66 are opposed to each other with the paper 3 interposed therebetween, and the axis of the drive roller 66 is inclined from the direction substantially orthogonal to the transport direction of the paper 3 toward the reference plane. And a slanting driven roller 67 arranged in the direction.

Then, the tray body 6 is fed from the paper feeding portion 61.
The paper 3 delivered to the 2 is fed by the skew roller 63.
While one widthwise end edge of the sheet 3 is in contact with the reference plate,
It is conveyed toward the image forming unit 5 via the re-conveyance path 65 again with the front and back reversed. Then, the rear surface of the sheet 3 conveyed to the image forming section 5 is brought into contact with the photosensitive drum 25 so that the visible image is transferred, and then the fixing section 1 is transferred.
In the state where it is fixed in 9 and images are formed on both sides,
The paper is discharged onto the paper discharge tray 51.

As shown in FIG. 2, the laser printer 1 is provided with a high voltage constant current power source 71, a voltmeter 72 as an electric characteristic detecting means, and a temperature / humidity sensor 73 as an environment detecting means. .

The high-voltage constant current power source 71 is the main casing 2
It is provided inside and is connected to the roller shaft 27a of the transfer roller 27, and is configured as a power source for applying a constant current transfer bias to the transfer roller 27.

The voltmeter 72 is arranged in the main body casing 2, and the wiring on one end side, which is the detection side, is in the middle of the wiring connecting the roller shaft 27a of the transfer roller 27 and the high-voltage constant-current power supply 71. And the wiring on the other end side is grounded. Then, in the voltmeter 72, the transfer roller 27 when the transfer bias is applied from the high voltage constant current power source 71
The voltage value En is detected as the electric characteristic of. In addition,
The voltage value En of the transfer roller 27 detected by the voltmeter 72 is used to judge the life of the transfer roller 27 by a life judgment program described later.

As shown in FIG. 3, the temperature / humidity sensor 73 is used for the transfer roller 2 at the center of the transfer roller 27 in the axial direction.
7 is provided in the vicinity of the downstream side of the transfer roller 2 at a predetermined interval so as not to come into contact with the transfer roller 27.
7 is configured to detect the temperature T and the humidity H of the installation environment. The temperature T and the humidity H detected by the temperature / humidity sensor 73 are used to judge the life of the transfer roller 27 by a life judgment program described later.

In the laser printer 1, the voltage value En of the transfer roller 27 detected by the voltmeter 72 is detected.
And the temperature T and humidity H detected by the temperature / humidity sensor 73, the life of the transfer roller 27 is determined.

FIG. 4 is a block diagram of a control system for executing such control. As shown in FIG. 4, in this control system, the I / O 6 is provided to the CPU 74 that controls each part.
9, a registration sensor 70, a voltmeter 72, a temperature / humidity sensor 73, a key input device 77, a motor drive circuit 78,
A high voltage constant current power source 71, a high voltage power source 79 and a display panel 80 as an informing means are connected.

Although not shown in FIG. 1, the key input device 77 is provided on the upper surface of the main body casing 2 and is provided with a plurality of keys so that the operator can input print setting information and the like. . An input signal from the key input device 77 is sent to the CPU 74 and used for various controls of the laser printer 1.

Although not shown in FIG. 1, the display panel 80 is provided on the upper surface of the main body casing 2 similarly to the key input device 77, and the life judgment program displays information such as the life of the transfer roller 27. The operator is notified by turning on a notification lamp or displaying on a liquid crystal panel or the like.

The CPU 74 has a ROM 75 and a RAM 7
6 is provided, and control of each part is performed. The ROM 75 stores a drive control program for executing the above-described image forming operation, a service life determining program as a service life determining unit described later, and the like. The RAM 72 stores temporary numerical values from the registration sensor 70, the voltmeter 72, the temperature / humidity sensor 73, the key input device 77, and the like for driving and controlling each unit.

A motor 81 is connected to the motor drive circuit 78, and the photosensitive drum 25, the cleaning roller 41, and the cleaning roller 41 are connected to the motor 81 via a gear train (not shown).
The backup roller 42, the developing roller 33, the charging roller 26, and the transfer roller 27 are connected. And
The motor 81 is connected to the CPU 7 via the motor drive circuit 78.
The drive control program stored in the ROM 75 of No. 4 controls the drive or stop. Therefore, the photosensitive drum 25, the cleaning roller 41, the backup roller 42, the developing roller 33, the charging roller 26, and the transfer roller 27 are controlled by the drive control program.
Its drive or stop is controlled.

The transfer roller 27 is connected to the high voltage constant current power source 71.
Is connected to the roller shaft 27a of
A drive control program stored in M75 controls ON / OFF of transfer bias application of the high-voltage constant-current power supply 71.

In the high voltage power supply 79, the roller shaft of the charging roller 26 via the charging circuit 83, the roller shaft of the developing roller 33 via the developing bias applying circuit 84, and the like.
The roller shafts of the cleaning roller 41 and the backup roller 42 are connected to each other via the cleaning bias applying circuit 85. Therefore, R of CPU74
By the drive control program stored in the OM75,
ON / OFF of charging is controlled via the charging circuit 83,
ON / OFF of the application of the developing bias is controlled via the developing bias applying circuit 84, and ON / OFF of the cleaning bias is applied via the cleaning bias applying circuit 85.
Off is controlled.

The life judgment program stored in the ROM 75 has a life table in which a life voltage value Eo is set as a reference value for judging the life of the transfer roller 27. More specifically, this life table is as shown in FIG.
5 ° C or lower, higher than 17.5 ° C and 26 ° C or lower, and 2
3 for temperature categories higher than 6 ° C and humidity H
0% or less, higher than 30% and 70% or less, and 70%
It has three higher humidity zones. And, corresponding to the combination of those temperature and humidity categories,
Life voltage value E, which is the reference value for the life judgment of the transfer roller 27
o are set respectively. Then, the life judgment program uses the life voltage value Eo in the life table corresponding to the temperature T and the humidity H detected by the temperature / humidity sensor 73, and the voltage value En of the transfer roller 27 detected by the voltmeter 72. Are compared with each other to determine the life of the transfer roller 27.

As described above, the life judgment program judges whether or not the transfer roller 27 is at the end of its life, and the judgment result is used as the life judgment value (for example, when the transfer roller 27 is at the end of life). , Life judgment value = YE
S, if it is not life, C is set as life judgment value = NO)
It is stored in a nonvolatile memory (not shown) in the PU 74.

Details of such control will be described below with reference to the flow chart shown in FIG.

First, when the printing process is started, the printing data is read, pre-printing processes such as setting the size of the paper 3 are performed (S1), and then stored in the non-volatile memory by the life judgment program. The life judgment value is read and judged (S2). If the life judgment value is NO (S2: NO), the high voltage power supply 79 is turned on by the drive control program, and the charging roller 2 is charged via the charging circuit 83.
6 is turned on, the developing bias to the developing roller 33 is turned on via the developing bias applying circuit 84, and the cleaning bias to the cleaning roller 41 and the backup roller 42 is turned on via the cleaning bias applying circuit 85. (S3). Next, after the high voltage constant current power supply 71 is turned on and a transfer bias of a predetermined constant current (for example, 10 μA) is turned on to the transfer roller 27 (S
4) The image forming process is performed (S5). Then, the temperature T (for example, 22 ° C.) and humidity H in the vicinity of the transfer roller 27 are measured by the temperature / humidity sensor 73.
(For example, 55%) is detected (S6), and the voltmeter 72 is detected.
The voltage value En of the transfer roller 27 (for example, 11
00V) is detected (S7). The voltage value En is
A predetermined time has passed after the trailing edge of the sheet 3 has passed the registration sensor 70, and the voltmeter 72 has passed when the sheet 3 has passed the contact portion between the photosensitive drum 25 and the transfer roller 27 and the image forming process has ended. Is the value detected by. As a result, according to the life judgment program, the life voltage value Eo in the life table corresponding to the current temperature T and humidity H
(1500V) is specified (S8), and then the specified lifetime voltage value Eo (1500V) is compared with the voltage value En (1100V) of the transfer roller 27 (S9). When the voltage value En of the transfer roller 27 is lower than the life voltage value Eo (S9: YES), all print data for one job is image-formed on the paper 3, and the paper 3 is discharged to the paper discharge tray 51. After that, by turning off the high voltage power supply 79, the charging of the charging roller 26 via the charging circuit 83 is turned off, the developing bias of the developing roller 33 via the developing bias applying circuit 84 is turned off, and the cleaning bias applying circuit is turned on. The cleaning bias to the cleaning roller 41 and the backup roller 42 via 85 is turned off (S10), the high-voltage constant current power source 71 is turned off, and the transfer bias of the transfer roller 27 is turned off (S11). Will be terminated.

On the other hand, in step 9, the transfer roller 2
Voltage value En of 7 (for example, at 22 ° C. and 55%, 150
0V) is equal to or higher than the life voltage value Eo (1500V) (S9: NO), the high voltage power supply 79 is turned off as in Steps 10 and 11, so that the charging roller 26, the developing unit The energization of the cartridge 28, the cleaning roller 41 and the backup roller 42 is stopped (S17), and the transfer bias to the transfer roller 27 is turned off (S18). Then, after the life judgment value is stored as YES in the non-volatile memory by the life judgment program (S19), a message indicating that the transfer roller 27 replacement time has come is displayed on the display panel 80, and is transferred to the operator. The end of the life of the roller 27 is notified (S20).

On the other hand, if the life judgment value is YES in step 2 for the next job (S2: Y
ES), the life judgment program displays a confirmation message on the display panel 80 as to whether or not the transfer roller 27 has reached the end of its life, but whether or not to continue the printing process, and the process by key input from the key input device 77 by the operator. Is prompted (S12). Next, the operator's selection is judged (S13). That is, when the operator makes a selection to continue the printing process using the key input device 77 (S
13: YES), as in step 3, the high voltage power supply is turned on, the charging roller 26, the developing cartridge 28, the cleaning roller 41, and the backup roller 42 are energized (S14), and the high voltage constant current power supply 71 is turned on. A transfer bias of a predetermined constant current is turned on to the transfer roller 27 (S15), and an image forming process is performed (S1).
6). Then, when the image forming process is completed,
Processing similar to that of step 17 to step 20 is performed (S17 to S20).

If the operator makes a selection to continue the printing process by the key input device 77 in step 13 (S13: NO), the process proceeds to step 20 and the display panel 80 is displayed by the life judging program. A message to the effect that the time to replace the transfer roller 27 has arrived is displayed, and the operator is notified of the end of the life of the transfer roller 27 (S20).

Thus, in this laser printer 1,
The voltmeter 72 detects the voltage value En when a constant current transfer bias is applied to the transfer roller 27, and the temperature / humidity sensor 73 detects the temperature T and the humidity H when the voltage value En of the transfer roller 27 is detected. , The detected voltage value En by the life judgment program
The temperature T and the humidity H are associated with each other to determine the life of the transfer roller 27. Therefore, the transfer roller 27
Whether or not is the life, whether the detected voltage value En is temperature T
Since the determination is made in consideration of the fluctuation of the humidity H and the humidity H, it is possible to accurately determine the life. Therefore, by appropriately replacing the transfer roller 27, it is possible to reduce maintenance cost and achieve good image formation.

More specifically, this life judgment program is provided with a life table in which the temperature T and the humidity H are associated with the life voltage value Eo which is a reference value for judging the life. Temperature T detected by
The life voltage of the transfer roller 27 is determined by specifying the life voltage value Eo corresponding to the humidity H and comparing the detected voltage value En of the transfer roller 27. Therefore, by comparing the specific life voltage value Eo corresponding to the detected temperature T and humidity H with the detected voltage value En using the life table, the life of the transfer roller 27 can be determined easily and reliably. can do. Therefore, the transfer roller 27 can be replaced more appropriately.

Further, in this life judgment program, the temperature / humidity sensor 73 detects the temperature T and the humidity H, respectively, and in the life table, the life voltage value Eo is calculated based on the detected temperature T and humidity H. Since the correspondence is made so as to be identifiable, the life voltage value Eo is specified in correspondence with the temperature T and the humidity H at the time of detecting the voltage value En of the transfer roller 27, and the life voltage value Eo is specified as the specified life voltage value Eo. By comparing the detected voltage value En of the transfer roller 27, the life of the transfer roller 27 is determined.
The life of the transfer roller 27 can be accurately determined, and the transfer roller 27 can be replaced more appropriately.

Further, the timing of detecting and displaying the end of life is after the image formation of one job is completed, but when it is detected that the end of life is reached, after the image formation of one page is completed, You may make it perform the process from step 17 to step 20.

As a method of judging the life of the transfer roller 27, a total power detection program serving as a total power detection means detects the total amount of electric power applied to the transfer roller 27, and the life judgment program is determined from the total amount of electric power. Alternatively, the life of the transfer roller 27 may be determined.

That is, the total power detection program is CP
It is stored in the ROM 75 of the U74 and includes a power calculation program as power calculation means and a total power calculation program as total power calculation means.

The power calculation program is configured to calculate the voltage value En of the transfer roller 27 when the constant-current transfer bias detected by the voltmeter 72 is applied, as the amount of power Es applied to the transfer roller 27. . More specifically, in this power calculation program, the paper size time Tz, which is the time during which the transfer bias is applied to the transfer roller 27 corresponding to the size of the paper 3, is set,
The paper size time Tz is, for example, A3 size paper 3
Is "3", and for A5 size paper 3, "2" is A6
“1.5” is set for each of the size sheets 3. Then, this power calculation program calculates the power amount Es for one sheet 3 based on the following equation 1.

Es = En × Tz Equation 1 The total power calculation program calculates the power amount Eu applied to the transfer roller 27 for each predetermined unit based on the power amount Es calculated by the power calculation program. The total electric energy EX applied to the transfer roller 27 is calculated by accumulating the electric energy Eu for each predetermined unit. More specifically, in this total power calculation program,
The number of sheets counter C is converted by the number of sheets of paper 3, and the predetermined unit is set as a process for each page of the paper 3, for example. Then, the total power calculation program calculates the total power amount EX based on the following equations 2 and 3.

Eu = Es × C Equation 2 EX = ΣEu Equation 3 The above-mentioned total electric energy EX is stored in the voltage counter of the nonvolatile memory in the CPU 74 by the life judgment program. It Further, in the life judgment program, the life total power value Ez is set as a reference value for judging whether or not the value of the voltage counter has reached the value of the life of the transfer roller 27. By comparing the total power value Ez and the value of the voltage counter,
The life of the transfer roller 27 is determined. The life total power value Ez is, for example, 72 in the control described below.
It is set to 0,000,000.

Next, according to the flow shown in FIG. 7, when the transfer roller 27 is new (that is, the value of the voltage counter is 0) and the environment is low temperature and low humidity (temperature 10 ° C., humidity 20%), one job is performed. The details of such control will be described by taking as an example the case where one sheet of A3 and three sheets of A5 are printed.

First, when the printing process is started, after the printing data is read and the pre-printing process such as the setting of the paper size is performed (S21), the high voltage power supply 79 is turned on by the drive control program, and the charging circuit is turned on. The charging of the charging roller 26 is turned on via 83, and the developing bias applying circuit 8
The developing bias to the developing roller 33 is turned on via No. 4, and the cleaning bias to the cleaning roller 41 and the backup roller 42 is turned on via the cleaning bias applying circuit 85 (S22). Next, after the high-voltage constant current power supply 71 is turned on and the transfer bias of a predetermined constant current is turned on to the transfer roller 27 (S23), the image forming process is performed (S24). Then, the process stands by until the image forming process on the sheet 3 is completed (S25: NO),
When a predetermined time elapses after the trailing edge of the sheet 3 passes the registration sensor 70, the sheet 3 passes the contact portion between the photosensitive drum 25 and the transfer roller 27, and the image forming process ends (S25: YES), the voltage value En of the transfer roller 27 is detected by the voltmeter 72. And, for example,
When the voltage value En at this time is 5,000 V, the electric power amount Es is calculated as Es = 5,000 × 3 by the electric power calculation program according to the above Expression 1. Then, based on the electric power amount Es, the total electric power calculation program subsequently calculates the total electric power amount EX by the formulas 2 and 3 as follows: Eu = 15,000 × 1 EX = 0 + 15,000.

Thereafter, this total electric energy EX is stored in the value of the voltage counter (S27). Next, it is judged from the print data and the paper size information read in step 21 whether or not the print processing is continuously performed (S2).
8) If printing is to be performed continuously (S28: Y)
ES), the process returns to step 24 again, and the image forming process is executed (S24). Then, similarly to the above, when the image forming process is completed (S25: YES), the voltmeter 72
Thus, the voltage value En of the transfer roller 27 is detected again. Then, when the voltage value En at this time is 4,500 V, the power amount Es is calculated as Es = 4,500 × 2 by the power calculation program according to the above-described formula 1. Then, based on this electric power amount Es, the total electric power calculation program subsequently calculates the total electric power amount EX as Eu = 9000 × 1 EX = 15,000 + 9,000 by the above-described equations 2 and 3. Next, it is judged from the print data or the paper size information read in step 21 whether or not the continuous print processing is to be performed (S28). If there is no data to be continuously printed (S28: NO), the high voltage power supply 79 is turned off, the charging of the charging roller 26 via the charging circuit 83 is turned off, the developing bias of the developing roller 33 via the developing bias applying circuit 84 is turned off, and the cleaning bias applying circuit. Cleaning roller 41 and backup roller 42 via 85
The cleaning bias is turned off (S29), the high voltage constant current power source 71 is turned off, and the transfer bias of the transfer roller 27 is turned off (S30).

Then, according to the life judgment program, the value (24,000) of the voltage counter indicates the life total power value Ez.
It is determined whether or not it is less than (720,000,000) (S31). Here, since the value of the voltage counter is less than the total lifetime power value Ez (S31: YES), the printing process ends.

Next, for example, in the laser printer 1 in which the value of the voltage counter is 719,999,000, which is close to the total life power value Ez, the high temperature and high humidity (temperature 32).
In the environment of (° C., 80% humidity), when three sheets of A3 size paper 3 are printed, first the first sheet 3 is processed from step 21 to step 26 in the same manner as above. When the voltage value En of the transfer roller 27 which has been processed and detected by the voltmeter 72 is 500 V, the power amount Es is Es = 500 × 1.5 according to the above equation 1 by the power calculation program. It is calculated. Then, based on this electric power amount Es, the total electric power calculation program subsequently calculates the total electric power amount EX as Eu = 750 × 1 EX = 719,999,000 + 750 by the above-described equations 2 and 3. Then, for the second and third sheets, similarly to the above, the transfer roller 27 detected in step 26 is also used.
If the voltage value En is 500 V, the value of the voltage counter in step 27 during the processing of the second sheet is 7
20,000,500, and the value of the voltage counter in step 27 at the time of processing the third sheet is 72.
It becomes 0,001,250. Then, similarly to the above, step 29 and step 30 are executed, and the value of the voltage counter (720,00
1,250) is the total life power value Ez (720,000)
It is determined whether it is less than (00) (S31). Then, since the value of the voltage counter exceeds the life total power value Ez (S31: NO), the life determination program
A message to the effect that the replacement time of the transfer roller 27 has arrived is displayed on the display panel 80, and the operator is notified of the end of the life of the transfer roller 27 (S32).

The power amount Eu for each predetermined unit calculated by such a total power calculation program may be calculated as a unit for each sheet 3 as described above.
It may be calculated for each job. That is,
For example, when a plurality of sheets are continuously printed by one job, the voltage value En of the transfer roller 27 is detected by the voltmeter 72 immediately before or after the processing of this one job, and the voltage value En is detected. The power amount Es is calculated by the power calculation program based on the paper size set for the job, and then the power amount Eu for each predetermined unit is calculated by the total power calculation program based on the number of prints set for the job. May be calculated.

In the laser printer 1, normally,
A reverse bias opposite to the transfer bias is applied to the transfer roller 27 when the power is turned on, after jam processing, or for each job, so that the toner adhering to the transfer roller 27 can be removed.
Although the cleaning mode for discharging to 5 is executed, the time for applying the reverse bias in this cleaning mode is shorter than the normal image forming time, so it is not considered in the above control, but in the power calculation program, It is also possible to calculate the power amount when the reverse bias is applied as described above and calculate the total power amount EX by the total power program based on this.

As described above, in the above-described method, the life determination program determines the life of the transfer roller 27 based on the total power amount EX detected by the total power amount detection program, that is, the total power amount EX is determined. Since the electric energy Es calculated from the voltage value En based on the temperature T and the humidity H at the time of detection is accumulated, the environmental factor has already been included, so that the temperature / humidity sensor 73 need not be provided separately. It is possible to accurately determine the life. Therefore, the transfer roller 2
By appropriately replacing 7, the maintenance cost can be reduced and good image formation can be achieved.

Further, this total electric energy detection program is executed by the voltage value E of the transfer roller 27 detected by the voltmeter 72.
The electric power calculation program calculates the electric energy Es based on n, and the electric energy Es and the number of sheets of paper 3 are converted to calculate the time during which the transfer bias is applied. Since the total power amount calculation program calculates the total power amount EX based on this, the total power amount EX can be calculated more easily and efficiently. Therefore, by appropriately replacing the transfer roller 27, it is possible to reduce the maintenance cost and achieve good image formation.

The total power amount calculation program is 1
Since the bias application time per sheet is determined, it is possible to calculate the total amount of electric power while simplifying the calculation for calculating the total amount of electric power and improving the efficiency.

Further, the total power calculation program uses the power amount E for each page or for each predetermined unit for each job.
Since the total electric energy EX is calculated by calculating u and accumulating the electric energy Eu for each predetermined unit, simplification and efficiency of the calculation for calculating the total electric energy EX are achieved. Therefore, a simple and efficient calculation of the total amount of electric power can be achieved.

Further, in the above control, the timing at which the voltage value En of the transfer roller 27 is detected by the voltmeter 72 is the time when the image forming process is completed, that is, the paper 3
After a predetermined time has passed after the trailing edge of the sheet passed the registration sensor 70 and the sheet 3 has passed the contact portion between the photosensitive drum 25 and the transfer roller 27, for example, before the image forming process, It may be at a time when the transfer roller 27 and the photosensitive drum 25 are in direct contact with each other.

Further, the transfer roller 2 by the voltmeter 72 is used.
The timing of detecting the voltage value En of 7 may be the time when the sheet 3 is between the transfer roller 27 and the photosensitive drum 25 and is in contact with the transfer roller 27. When the voltage value En of the transfer roller 27 is detected at such a timing, the voltage value En in a state more conforming to the actual use state is detected, so that the transfer roller 27 more conforming to the actual use state is detected. Life can be judged.

As a method of judging the life of the transfer roller 27, a reference roller 86 as a reference conductive member having the same physical properties as the transfer roller 27 and arranged in the same environment is prepared. Voltage value E of the reference roller 86
It is also possible to compare r with the voltage value En of the transfer roller 27.

FIG. 8 is a block diagram showing the vicinity of the transfer roller 27 of the laser printer 1 having such a structure.

That is, in FIG. 8, the reference roller 86
Is disposed below the photosensitive drum 25, on the downstream side of the transfer roller 27 in the rotating direction of the photosensitive drum, and on the upstream side of the cleaning roller 41 so as to face the photosensitive drum 25 and rotate in the drum cartridge 23. Supported as possible. The reference roller 86 is
Although it has a smaller diameter than the transfer roller 27, it is made of a material having the same physical properties as the transfer roller 27, that is, the metal roller shaft 86a is covered with a roller made of an ion conductive rubber material. ing. The reference roller 86 is always separated from the photosensitive drum 25 by a contacting / separating mechanism portion 87 described later, and the photosensitive drum 2 is detected when the voltage value Er of the reference roller 86 described later is detected.
5 is configured to be able to come into contact with and separate from the photosensitive drum 25.

The reference roller 86 is the transfer roller 27.
It may be arranged on the same axial end as the transfer roller 27 in the axial direction.

In the laser printer 1, the wiring from the high voltage constant current power source 71 is connected to the power source side switch 89.
It is branched into two, one side of which is connected to the roller shaft 27a of the transfer roller 27, and the other side is
It is connected to the roller shaft 86 a of the reference roller 86.

The wiring connected to the voltmeter 72 is also branched into two from the voltmeter side switch 90, one side of which is connected to the roller shaft 27a of the transfer roller 27 and the other side. Is connected to the roller shaft 86a of the reference roller 86. In such a circuit configuration, as shown in FIG. 8A, the voltage value En of the transfer roller 27 is detected by connecting both the power source side switch 89 and the voltmeter side switch 90 to the roller shaft 27a side. A transfer roller voltage detection circuit as an electric characteristic detection means is configured, and by connecting both the power supply side switch 89 and the voltmeter side switch 90 to the reference roller shaft 86a side as shown in FIG. 8B. A reference roller voltage detection circuit as reference electrical characteristic detection means for detecting the voltage value Er of the reference roller 86 is configured.

FIG. 9 shows a block diagram of the control section of such a laser printer 1. In FIG. 9, the same members as those in the block diagram shown in FIG. 4 are designated by the same reference numerals, and the description thereof will be omitted.

That is, referring to FIG. 9, in the control section of the laser printer 1, the contact / separation mechanism section 87 as a contact / separation mechanism is used.
And the switch circuit 88 connects the CPU 7 via the I / O 69.
4 is connected.

A reference roller 86 is connected to the contact / separation mechanism section 87. The contact / separation mechanism section 87 is composed of a drive mechanism such as a cam (not shown), and
As shown in FIG. 8A, the reference roller 86 is separated from the photosensitive drum 25, and when the voltage value Er of the reference roller 86 is detected by the voltmeter 72, as shown in FIG. The reference roller 86 is configured to contact the photosensitive drum 25.

The switch circuit 88 includes a power source side switch 8
9 and a voltmeter side switch 90 are connected. Therefore, the ROM of the CPU 74 is connected via the switch circuit 88.
The life determination program stored in 75 controls the switching of the power source side switch 89 and the voltmeter side switch 90.

In addition, in the life judgment program of this laser printer 1, when the voltage value Er of the reference roller 86 and the voltage value En of the transfer roller 27 are compared to judge whether or not the transfer roller 27 has reached the life, Voltage value Er of the reference roller 86
The reference roller voltage addition value K to be added to is set.
That is, the reference roller 86 is made of the same material as the transfer roller 27 and has the same physical properties,
Since the diameter and the axial length of the transfer roller 27 are different from those of the transfer roller 27, the reference roller voltage added value K is set in consideration of this and the reference roller voltage added value K is set to the reference roller 86.
It is configured so that the life of the transfer roller 27 can be accurately determined by adding it to the voltage value Er.

In the laser printer 1, the voltage value Er of the reference roller 86 in an environment of normal temperature and normal humidity (for example, temperature 23 ° C., humidity 60%) is 1,000 V, and the reference roller voltage added value K is The voltage value Er of the reference roller 86 in the environment of low temperature and low humidity (for example, temperature 10 ° C., humidity 20%) is 4,500 V, and the reference roller voltage addition value K is set to 1,000 V. The voltage value Er of the reference roller 86 in a high temperature and high humidity environment (for example, temperature 32 ° C., humidity 80%) is 500V,
The reference roller voltage addition value K is set to 100V. Note that the relationship between temperature and humidity is classified into nine such as normal temperature and normal humidity, low temperature and constant humidity, and high temperature and high humidity in the range with reference to the vertical axis and the horizontal axis in FIG. 5, and the reference roller voltage added value for each of these classifications. K is set.

Next, a method of determining the life of the transfer roller 27 by the life determining program in the laser printer 1 will be described in detail with reference to FIG.

First, at the time of image formation, FIG.
As shown in FIG.
Is connected to the high voltage constant current power supply 71.
From the above, a constant current transfer bias is applied to the transfer roller 27. On the other hand, the voltmeter-side switch 90 is open as shown by the dotted line, and the reference roller 86 is separated from the photosensitive drum 25 by the contact / separation mechanism section 87.

When the image forming process is completed, the transfer bias remains on and the voltmeter side switch 90 is connected to the transfer roller 27 side as shown by the solid line. Then, the voltage value En of the transfer roller 27 is detected by the voltmeter 72, the voltage value En is stored in the RAM 25, and then the power supply side switch 89 and the voltmeter side switch 90 are opened as shown by the dotted line. .

Next, as shown in FIG. 8B, the reference roller 86 is brought into contact with the photosensitive drum 25 by the contact / separation mechanism portion 87, and as shown by the solid line, the power source side switch 89 and the voltmeter side. The switch 90 is connected to the reference roller 86 side. Then, the voltage value Er of the reference roller 86
Is detected by the voltmeter 72, and the voltage value Er of the reference roller 86 is stored in the RAM 75. Then, the reference roller 86 is separated from the photosensitive drum 25 by the contact / separation mechanism section 87, and as shown by the dotted line, Power switch 8
9 and the voltmeter side switch 90 are opened.

Then, the life judging program compares the voltage value En of the transfer roller 27 with the value obtained by adding the reference roller added voltage value K to the voltage value Er of the reference roller 86. For example, in a normal temperature and normal humidity environment (for example, temperature 23 ° C., humidity 60%), the detected voltage value Er of the reference roller 86 is 1,000 V, and the detected voltage value En of the transfer roller 27 is 1,000 V. In the case, the reference roller addition voltage value K in this environment, that is, 500V is added to the voltage value Er of the reference roller 86, and the 1,500V and the voltage value En of the transfer roller 27 are compared. In this case, the voltage value En of the transfer roller 27
Is less than 1,500V, the transfer roller 27
Is judged not to be a lifetime. At this time, for example, when the voltage value En of the transfer roller 27 is 1,500 V or more, the transfer roller 27 is determined to have reached the end of its life.

Further, for example, in the environment of low temperature and low humidity (for example, temperature 10 ° C., humidity 20%), the detected voltage value Er of the reference roller 86 is 4,500 V, and the detected voltage value En of the transfer roller 27 is En. Is 5,000 V, the reference roller addition voltage value K in this environment is added to the voltage value Er of the reference roller 86, that is, 1,000 V.
Is added and the voltage value En of the transfer roller 27 is compared with this 5,500V. In this case, since the voltage value En of the transfer roller 27 is less than 5,500 V, it is determined that the transfer roller 27 has not reached the end of its life. At this time, for example, the voltage value En of the transfer roller 27 is
Is 5,500 V or more, the transfer roller 27 is determined to have reached the end of its life.

Further, for example, in a high temperature and high humidity environment (for example, temperature 32 ° C., humidity 80%), the detected voltage value Er of the reference roller 86 is 500 V, and the detected voltage value En of the transfer roller 27 is When the voltage is 500V, the reference roller addition voltage value K in this environment, that is, 100V is added to the voltage value Er of the reference roller 86, and this 600V is compared with the voltage value En of the transfer roller 27. In this case, the voltage value E of the transfer roller 27
Since n is less than 600V, this transfer roller 27
Is judged not to be a lifetime. At this time, for example, when the voltage value En of the transfer roller 27 is 600 V or more, the transfer roller 27 is determined to have reached the end of its life.

As described above, the reference roller 86 has the same physical properties as the transfer roller 27, is arranged in the same environment, and is the same as the transfer roller 27 except that the transfer bias is not applied during image formation. Since the environmental history is received, if the reference roller 86 and the transfer roller 27 are relatively compared with each other to determine the life of the transfer roller 27, the environmental change can be more closely matched. The life of the transfer roller 27 can be determined, and more accurate and accurate life can be determined. for that reason,
By appropriately replacing the transfer roller 27, it is possible to reduce maintenance costs and achieve good image formation.

Further, according to this method, the reference roller 86 is always separated from the photosensitive drum 25 by the contact / separation mechanism portion 87, while the reference roller 86 is moved to the photosensitive drum 25 when the voltage value Er of the reference roller 86 is detected by the voltmeter 72. Since they are brought into contact with each other, the voltage value En of the transfer roller 27 and the voltage value Er of the reference roller 86 are detected under the same condition. Therefore, more accurate determination of the life of the transfer roller 27 can be achieved by accurate relative comparison. Further, since the reference roller 86 is separated from the photosensitive drum 25 by the contact / separation mechanism portion 87 except when the voltage value Er thereof is detected, an electrical load from the photosensitive drum 25 is not always applied. , As a reference for the transfer roller 27, is held in a good state. Therefore, the life of the transfer roller 27 can be more accurately determined.

In the method of determining the life of the transfer roller 27 described above, the bias voltage applied to the transfer roller 27 is controlled to a constant current, and the voltage value En generated from the transfer roller 27 is detected by the voltmeter 72. As a result, the detection of the electrical characteristics of the transfer roller 27 can be achieved simply and reliably. Therefore, the transfer roller 2
It is possible to achieve accurate determination of the life of the transfer roller 7 and to replace the transfer roller 27 more appropriately.

In the laser printer 1 described above, since the roller 27b of the transfer roller 27 is formed of an ion conductive rubber member, the resistance value changes remarkably depending on the environment. Since it is possible to accurately determine the life of the transfer roller 27 by a program, it is possible to always achieve good image formation by appropriately replacing the transfer roller 27.

Further, in this method, the voltage value En of the transfer roller 27 is detected while the transfer roller 27 is in contact with the photosensitive drum 25. Therefore, the voltage value in a state corresponding to the actual use mode at the time of image formation. Since the detection of En is realized, the life of the transfer roller 27 can be determined more reliably.

The transfer roller 27 is the photosensitive drum 25.
This is an image transfer member that electrically attracts the visible image formed in the above. Since a large transfer bias is applied, in particular, the resistance value is largely increased due to durability, and the transfer failure is likely to occur.

However, with this method, it is possible to accurately determine the life of the transfer roller 27, and the transfer roller 2
Since it is possible to replace 7 more appropriately, it is possible to always secure good transfer and achieve good image formation.

Further, in this method, when the transfer roller 27 is judged to have reached the end of its life by the life judgment program, the display panel 80 notifies the operator of the end of the life. By recognizing that the transfer roller 27 has reached the end of its life, the transfer roller 27 can be replaced accurately. Therefore, by appropriately replacing the transfer roller 27, it is possible to reduce the maintenance cost and achieve good image formation.

In the above embodiment, a constant current is applied to the transfer bias by constant current control, whereby the transfer roller 27 and / or the reference roller 8 are applied.
As the electrical characteristics of 6, the voltage value is detected by the voltmeter 72 and the life is judged based on the voltage value. For example, the transfer bias is controlled by a constant voltage control to apply a constant voltage. As the electric characteristics of the transfer roller 27 and / or the reference roller 86, a current value may be detected by an ammeter and the life may be determined based on the current value. Even with this method, you can easily and surely
The electric characteristics of the transfer roller 27 are detected and the transfer roller 27 is detected.
It is possible to accurately determine the life of the transfer roller 27, and it is possible to more appropriately replace the transfer roller 27.

Further, a resistance measuring electrode may be connected to the transfer roller 27 to measure the resistance value as an electric characteristic of the transfer roller 27.

FIG. 10 is a block diagram showing the vicinity of the transfer roller 27 of the laser printer 1 having such a structure. In FIG. 10, the same members as those shown in FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted.

That is, in FIG. 10, the laser printer 1 has a resistance value measuring device 9 as an electric characteristic detecting means.
1 is provided.

The resistance value measuring device 91 is connected to the roller shaft 27a of the transfer roller 27 and has a resistance value measuring electrode 92. The resistance value measuring electrode 92 is made of a metal roller and is arranged in contact with the transfer roller 27. The resistance value measuring device 91 is configured to directly detect the resistance value of the transfer roller 27 to which a predetermined transfer bias is applied. Further, in this case, the life judgment program includes a life table in which a life resistance value is set as a reference value for judging the life of the transfer roller 27, for example. This life table is, more specifically, as shown in FIG. 11, for the temperature T, 17.5.
℃ or less, higher than 17.5 ℃ and 26 ℃ or less, and 26
30 for three temperature categories above ℃ and humidity H
%, Less than 30% and less than 70%, and three humidity categories greater than 70%. Then, a life resistance value serving as a reference value for the life judgment of the transfer roller 27 is set corresponding to each combination of the temperature classification and the humidity classification. Then, the life judgment program compares the life resistance value in the life table corresponding to the temperature T and the humidity H detected by the temperature / humidity sensor 73 with the resistance value of the transfer roller 27 detected by the voltmeter 72. By doing so, the life of the transfer roller 27 is determined.

Even with such a method, the life of the transfer roller 27 can be determined easily and reliably.

Although the transfer roller 27 is exemplified as the conductive member (transfer member) in the above-mentioned embodiment,
The conductive member (transfer member) may be, for example, a transfer belt (including an intermediate transfer belt used in an intermediate transfer type color laser printer).

Even with the transfer belt, as with the transfer roller 27, a large transfer bias is applied.
Although the resistance value increases greatly due to endurance and a transfer failure is likely to occur, the life judgment program described above makes it possible to accurately judge the life of the transfer belt, and more appropriately replace the transfer belt. Therefore, good transfer can always be ensured and good image formation can be achieved.

Further, as the conductive member, if a bias is applied and its electrical characteristics (voltage, current, resistance value) change due to durability, which affects the image quality, etc. Not limited to the roller 27,
Other members, such as a charging roller, a developing roller, or a cleaning roller, arranged to face the photosensitive drum 25 may be used.

Further, in the present embodiment, the display panel is adopted as the notifying means, but the notification may be made, for example, by turning on a lamp, or by a sound such as a buzzer or an announcement. .

In the above-described embodiment, the voltage value En of the transfer roller 27 is detected after image formation, but the voltage value En (current value or resistance value may be used).
If the transfer bias is applied to the transfer roller 27, the detection may be performed before the image formation.

[0183]

As described above, according to the first aspect of the present invention, maintenance cost can be reduced and good image formation can be achieved by appropriately replacing the conductive member.

According to the second aspect of the present invention, the life of the conductive member can be determined easily and reliably, and the conductive member can be replaced more appropriately.

According to the third aspect of the present invention, the life of the conductive member can be determined more reliably.

According to the invention described in claim 4, it is possible to more accurately determine the life of the conductive member, and it is possible to more appropriately replace the conductive member.

According to the fifth aspect of the present invention, it is possible to reduce the maintenance cost and achieve good image formation by appropriately replacing the conductive member.

According to the sixth aspect of the present invention, the maintenance cost can be reduced and good image formation can be achieved by appropriately replacing the conductive member.

According to the invention as set forth in claim 7, it is possible to calculate the total amount of electric power almost accurately while simplifying the calculation for calculating the total amount of electric power and improving the efficiency.

According to the invention described in claim 8, it is possible to further judge the life of the conductive member according to the actual use mode.

According to the ninth aspect of the present invention, it is possible to easily and efficiently calculate the total amount of electric power.

According to the tenth aspect of the present invention, the maintenance cost can be reduced and excellent image formation can be achieved by appropriately replacing the conductive member.

According to the eleventh aspect of the present invention, the life of the conductive member can be more accurately determined.

According to the twelfth aspect of the present invention, it is possible to achieve a simple and reliable determination of the life of the conductive member by detecting at least one of the current value, the voltage value and the resistance value.

According to the thirteenth aspect of the present invention, the bias applied to the conductive member is controlled to a constant current, and the voltage value generated from the conductive member is detected by the voltmeter. Detection can be achieved, more accurate determination of the life of the conductive member can be achieved, and more appropriate replacement of the conductive member can be achieved.

According to the fourteenth aspect of the present invention, the bias applied to the conductive member is controlled to a constant voltage, and the current value generated from the conductive member is detected by the ammeter. Detection can be achieved, more accurate determination of the life of the conductive member can be achieved, and more appropriate replacement of the conductive member can be achieved.

According to the fifteenth aspect of the present invention, since it is possible to accurately determine the life of the conductive member, it is possible to always achieve good image formation by appropriately replacing the conductive member.

According to the sixteenth aspect of the present invention, the life of the conductive member can be determined more reliably.

According to the seventeenth aspect of the present invention, it is possible to always ensure good transfer and achieve good image formation.

According to the eighteenth aspect of the present invention, it is possible to accurately determine the life of the transfer roller, and it is possible to more appropriately replace the transfer roller. Therefore, good transfer is always ensured. Thus, good image formation can be achieved.

According to the nineteenth aspect of the present invention, it is possible to accurately determine the life of the transfer belt and to more appropriately replace the transfer belt, so that good transfer is always ensured. Thus, good image formation can be achieved.

According to the twentieth aspect of the present invention, it is possible to further reduce the maintenance cost and achieve good image formation by appropriately exchanging the conductive member.

[Brief description of drawings]

FIG. 1 is a side sectional view of an essential part showing an embodiment of a laser printer as an image forming apparatus of the present invention.

FIG. 2 is a main part configuration diagram in the vicinity of a transfer roller of the laser printer shown in FIG.

FIG. 3 is a schematic plan view of a transfer roller of the laser printer shown in FIG.

FIG. 4 is a block diagram of a control system of the laser printer shown in FIG.

5 is a diagram showing a life table of a life determination program for the laser printer shown in FIG.

6 is a flow chart of control of a life determination program for the laser printer shown in FIG.

FIG. 7 is a control flowchart of another embodiment (determining the life of the transfer roller from the total amount of power) of the life determining program for the laser printer shown in FIG.

8 is a main part configuration diagram of another embodiment (a reference roller is provided to determine the life of the transfer roller) near the transfer roller of the laser printer shown in FIG.

9 is a block diagram of a control system of the laser printer shown in FIG.

10 is a main part configuration diagram of another embodiment (a resistance value measuring device is provided to determine the life of the transfer roller) near the transfer roller of the laser printer shown in FIG.

11 is a diagram showing a life table of a life determination program for the laser printer shown in FIG.

[Explanation of symbols]

1 laser printer 3 sheets 25 photosensitive drum 26 Charging roller 27 Transfer roller 33 developing roller 41 Cleaning roller 72 Voltmeter 73 Temperature and humidity sensor 80 display panel 86 Reference roller 87 Contact / separation mechanism section 91 Resistance value measuring device

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/08 501 501 G03G 15/08 501D 15/16 103 15/16 103 21/10 21/00 312 (72) ) Inventor Hideaki 15-1 Naedai-cho, Mizuho-ku, Nagoya-shi F-term in Brother Industries, Ltd. (reference) 2H027 DA01 DA13 DA14 DA39 DA41 DA50 DE05 DE07 EF06 EF13 GA43 GA48 GB01 HB01 HB16 ZA07 2H073 AA02 BA13 BA23 BA27 BA33 2H077 AD06 AD13 AE04 DA22 DA43 DA57 EA14 FA13 FA27 GA02 GA03 2H134 GA01 GB02 GB05 HA11 HA12 HA17 KA08 KA13 KA28 KA30 KD07 KG01 KG03 KG04 KH01 KH04 KH16 KJ03 2H200 FA01 H02B22 HA02B22 HA22B22 HA22B30 HA02 GA20 GA20 GA20 GA20 GA20 GA20 GA20 JA25 JA26 JA28 JA29 JA30 JB13 JB17 JB20 JC02 JC03 JC15 JC16 JC18 JC19 JC20 MA03 MA08 MB01 MB02 NA16 PA24 PA27 PB03 PB27 PB 28 PB33 PB34 PB35 PB38

Claims (20)

[Claims] 1. An image forming apparatus including a conductive member to which a bias is applied during image formation, wherein an electric characteristic detecting unit for detecting an electric characteristic of the conductive member; an environment detecting unit for detecting an environment; An image forming method, comprising: a life determining unit that determines the life of the conductive member based on the electrical characteristics of the conductive member detected by the characteristic detecting unit and the environment detected by the environment detecting unit. apparatus. 2. The life determining means includes a life table in which an environment and a reference value of an electrical characteristic to be judged as a life are associated with each other, and the life table indicates an electrical property corresponding to the detected environment. The image forming apparatus according to claim 1, wherein a life of the conductive member is determined by identifying a reference value of a characteristic and comparing the value with a detected electrical characteristic. 3. The environment detecting means detects temperature and / or humidity.
The image forming apparatus according to item 1. 4. The image forming according to claim 2, wherein the life table is associated with the reference value of the electric characteristic so as to be specified based on the temperature and the humidity. apparatus. 5. An image forming apparatus including a conductive member to which a bias is applied during image formation, wherein a total power amount detecting unit for detecting a total power amount applied to the conductive member; and a total power amount detecting unit. An image forming apparatus comprising: a life determining unit that determines a life of the conductive member based on a total amount of electric power detected by the image forming apparatus. 6. The total electric energy detecting means includes an electric characteristic detecting means for detecting an electric characteristic of the conductive member, and a power calculating means for calculating electric power based on the electric characteristic detected by the electric characteristic detecting means. 6. The total electric energy calculating means for calculating the total electric energy based on the electric power calculated by the electric power calculating means and the bias application time, and the total electric energy calculating means according to claim 5, Image forming apparatus. 7. The image according to claim 6, wherein the total electric power amount calculating means calculates the bias application time by converting the number of contact media in contact with the conductive member. Forming equipment. 8. The image forming apparatus according to claim 7, wherein the electrical characteristic detecting unit detects an electrical characteristic when the contact medium is in contact. 9. The image forming apparatus according to claim 5, wherein the total power calculation means calculates a power amount for each predetermined unit and accumulates the calculated power amount. 10. An image forming apparatus provided with a conductive member to which a bias is applied during image formation, comprising: an electrical characteristic detection unit for detecting an electrical characteristic of the conductive member; and physical properties similar to those of the conductive member, A reference conductive member that is arranged in the same environment and to which a bias is not applied during image formation, a reference electric characteristic detection unit for detecting electric characteristics of the reference conductive member, and the electric conductivity detected by the electric characteristic detection unit. A life judging means for judging the life of the conductive member by comparing the electric characteristics of the member and the electric characteristics of the reference conductive member detected by the reference electric characteristic detecting means. An image forming apparatus. 11. A contact for always separating the reference conductive member from a contact member with which the conductive member is in contact when a bias is applied so that the reference conductive member is brought into contact with the reference electric characteristic detecting means when the electric characteristic is detected. The image forming apparatus according to claim 10, further comprising a separating mechanism. 12. The image forming apparatus according to claim 1, wherein the electric characteristic is at least one of a current value, a voltage value, and a resistance value. 13. The image forming apparatus according to claim 12, wherein a bias is applied to the conductive member with a constant current, and the electrical characteristic detection unit detects a voltage value. 14. The image forming apparatus according to claim 12, wherein a bias is applied to the conductive member at a constant voltage, and the electrical characteristic detection unit detects a current value. 15. The image forming apparatus according to claim 1, wherein the conductive member is an ion conductive member. 16. The electrically conductive member is any one of a charging member, a developing member, a transfer member, and a cleaning member, which are arranged to face an image carrier on which an electrostatic latent image is formed, and the electrical characteristics of the electrically conductive member. 16. The image forming apparatus according to claim 1, wherein the image carrier is used when detecting the. 17. The image transfer member according to claim 16, wherein the transfer member is an image transfer member that electrically attracts a developer image formed by developing the electrostatic latent image on the image carrier. Image forming device. 18. The image forming apparatus according to claim 16, wherein the transfer member is a transfer roller. 19. The image forming apparatus according to claim 16, wherein the transfer member is a transfer belt. 20. An informing means for informing that the life of the conductive member is reached when the life determining means determines that the conductive member has reached the end of its life. An image forming apparatus according to claim 2.