JP7533052B2 - Drum Cartridge - Google Patents

Description

This disclosure relates to a drum cartridge that allows the development roller to be separated from the photosensitive drum.

There is a known drum cartridge that allows the developing roller to be separated from the photosensitive drum (see Patent Document 1). In an image forming device equipped with this drum cartridge, the time that the developing roller is in contact with the photosensitive drum during image formation is counted. Then, when the time that the developing roller is in contact with the photosensitive drum reaches a threshold value, it is determined that the photosensitive drum has reached the end of its life.

JP 2003-323090 A

However, the technology in Patent Document 1 does not take into account the amount of wear when the developing roller is separated from the photosensitive drum, so it may not be possible to accurately calculate the amount of wear on the photosensitive drum.

Therefore, the present disclosure aims to make it possible to accurately calculate the amount of wear on a photosensitive drum.

The drum cartridge for solving the above-mentioned problem includes a photosensitive drum and a drum memory. The photosensitive drum rotates about a first axis extending in the axial direction. The photosensitive drum is in a contact state where the outer circumferential surface of the developing roller is in contact with the outer circumferential surface of the photosensitive drum, or in a separated state where the outer circumferential surface of the developing roller is separated from the outer circumferential surface of the photosensitive drum. The drum memory has a first storage area that stores a first rotation count, which is the number of times the photosensitive drum has rotated in the contact state, and a second storage area that stores a second rotation count, which is the number of times the photosensitive drum has rotated in the separated state.

With this configuration, the number of rotations in the contact state and the number of rotations in the separated state are stored separately in the drum memory, making it possible to accurately calculate the amount of wear on the photosensitive drum.

In addition, in the drum cartridge described above, the first storage area may be configured to store a first total number of rotations, which is the cumulative number of times the photosensitive drum has rotated in a contact state since the photosensitive drum was first used, as the first number of rotations, and the second storage area may be configured to store a second total number of rotations, which is the cumulative number of times the photosensitive drum has rotated in a separated state since the photosensitive drum was first used, as the second number of rotations.

With this configuration, the total number of rotations of the photosensitive drum in a contact state since the start of use and the total number of rotations of the photosensitive drum in a separated state since the start of use are stored separately in the drum memory, making it possible to accurately calculate the amount of wear on the photosensitive drum.

In addition, in the drum cartridge described above, the amount of wear of the photosensitive drum caused by the rotation of the photosensitive drum may be determined based on the first total number of rotations and the second total number of rotations.

In addition, in the drum cartridge described above, the amount of wear of the photosensitive drum caused by the rotation of the photosensitive drum may be determined by adding the number obtained by multiplying the first total number of rotations by a first coefficient and the number obtained by multiplying the second total number of rotations by a second coefficient that is smaller than the first coefficient.

In addition, in the drum cartridge described above, the first storage area may further store a first coefficient corresponding to a first number of rotations, and the second storage area may further store a second coefficient corresponding to a second number of rotations, the second coefficient being smaller than the first coefficient.

With this configuration, the amount of wear of the photosensitive drum is calculated based on the contact or separation state, as well as based on a first coefficient corresponding to the first number of rotations and a second coefficient corresponding to the second number of rotations, making it possible to calculate the amount of wear according to the state when the photosensitive drum is rotating.

In addition, in the drum cartridge described above, the amount of wear of the photosensitive drum caused by the rotation of the photosensitive drum may be determined by adding together the cumulative number of times the first rotation is multiplied by a first coefficient and the cumulative number of times the second rotation is multiplied by a second coefficient that is smaller than the first coefficient.

With this configuration, the amount of wear of the photosensitive drum is calculated based on the contact or separation state, as well as based on a first coefficient corresponding to the first number of rotations and a second coefficient corresponding to the second number of rotations, making it possible to calculate the amount of wear according to the state when the photosensitive drum is rotating.

In addition, in the drum cartridge described above, the first coefficient and the second coefficient may be configured to be values that change based on the temperature of the photosensitive drum when the photosensitive drum is rotated.

This allows the amount of wear on the photosensitive drum to be calculated accurately, since it is based on the contact or separation state and on the temperature of the photosensitive drum when it rotates.

In addition, in the drum cartridge described above, the first coefficient and the second coefficient may be configured to be values that are determined to be larger as the total number of rotations of the photosensitive drum since the photosensitive drum began to be used increases.

This allows the amount of wear to be calculated based on the contact or separation state as well as the total number of rotations of the photosensitive drum, making it possible to accurately calculate the amount of wear on the photosensitive drum.

In addition, the drum cartridge described above may be used together with a developing cartridge including a developing roller, and the developing cartridge may be configured to be attachable or detachable.

The drum cartridge may also be configured to include a separation mechanism that switches between a contact state and a separated state.

The drum cartridge described above may also be configured as a drawer that has multiple photosensitive drums and can be pulled out from the main body of the image forming device.

The drum cartridge for solving the above-mentioned problem includes a photosensitive drum and a drum memory. The photosensitive drum rotates about a first axis extending in the axial direction. The photosensitive drum is in a contact state where the outer circumferential surface of the developing roller is in contact with the outer circumferential surface of the photosensitive drum, or in a separated state where the outer circumferential surface of the developing roller is separated from the outer circumferential surface of the photosensitive drum. The drum memory stores the amount of wear of the photosensitive drum worn by the rotation of the photosensitive drum, which is determined based on a first rotation count, which is the number of times the photosensitive drum rotates in a contact state, and a second rotation count, which is the number of times the photosensitive drum rotates in a separated state.

With this configuration, the amount of wear on the photosensitive drum is determined based on the number of rotations in the contact state and the number of rotations in the separated state and is stored in the drum memory, making it possible to accurately calculate the amount of wear on the photosensitive drum.

In addition, in the drum cartridge described above, the amount of wear of the photosensitive drum caused by the rotation of the photosensitive drum may be determined by adding a number obtained by multiplying a first coefficient to a first total number of rotations, which is the cumulative number of times the photosensitive drum has rotated in a contact state since the photosensitive drum was first used, and a number obtained by multiplying a second coefficient smaller than the first coefficient to a second total number of rotations, which is the cumulative number of times the photosensitive drum has rotated in a separated state since the photosensitive drum was first used.

With this configuration, the amount of wear of the photosensitive drum is calculated based on the contact or separation state, as well as based on a first coefficient corresponding to the first number of rotations and a second coefficient corresponding to the second number of rotations, making it possible to calculate the amount of wear according to the state when the photosensitive drum is rotating.

In addition, in the drum cartridge described above, the amount of wear of the photosensitive drum caused by the rotation of the photosensitive drum may be determined by adding together the cumulative number of times the first rotation is multiplied by a first coefficient corresponding to the first rotation, and the cumulative number of times the second rotation is multiplied by a second coefficient corresponding to the second rotation, the second coefficient being smaller than the first coefficient.

With this configuration, the amount of wear of the photosensitive drum is calculated based on the contact or separation state, as well as based on a first coefficient corresponding to the first number of rotations and a second coefficient corresponding to the second number of rotations, making it possible to calculate the amount of wear according to the state when the photosensitive drum is rotating.

In addition, in the drum cartridge described above, the first coefficient and the second coefficient may be configured to be values that are determined to be smaller as the temperature of the photosensitive drum when the photosensitive drum is rotated increases.

This allows the amount of wear on the photosensitive drum to be calculated accurately, since it is based on the contact or separation state and on the temperature of the photosensitive drum when it rotates.

In addition, in the drum cartridge described above, the first coefficient and the second coefficient may be configured to be values that are determined to be larger as the total number of rotations of the photosensitive drum since the photosensitive drum began to be used increases.

This allows the amount of wear to be calculated based on the contact or separation state as well as the total number of rotations of the photosensitive drum, making it possible to accurately calculate the amount of wear on the photosensitive drum.

In addition, the drum cartridge described above may be used together with a developing cartridge including a developing roller, and the developing cartridge may be configured to be attachable or detachable.

The drum cartridge may also be configured to include a separation mechanism that switches between the contact state and the separated state.

The drum cartridge described above may also be configured as a drawer that has multiple photosensitive drums and can be pulled out from the main body of the image forming device.

1 is a diagram showing a schematic configuration of an image forming apparatus according to an embodiment; FIG. 2 is an exploded perspective view showing a drawer and a separation mechanism for the drawer. 3A is a perspective view of a developing cartridge, and FIG. 4A and 4B are schematic diagrams illustrating the periphery of the developing cartridge as viewed from above, showing when the developing roller is in a contact state and when the developing roller is in a separated state. 4 is a diagram showing the inner surface (developer cartridge side) of the side frame of the drawer. FIG. 4 is a diagram showing electrical connections between a control unit, a main body memory, a drum memory, a temperature sensor, and each motor. FIG. 5 is a table showing information stored in a first storage area and a second storage area of a drum memory in the first embodiment. 5 is a flowchart showing a process in which the control unit stores information in the drum memory in the first embodiment. 5 is a flowchart showing a lifespan determination process in the first embodiment. 1 is a graph showing the relationship between the total number of rotations of a photosensitive drum and the amount of wear, and showing the transition of the calculated amount of wear in an embodiment (solid line) and the prior art (dashed line). 13 is a map of coefficients according to the state of the photosensitive drum in the second embodiment. 13 is a table showing information stored in a first storage area and a second storage area in the second and third embodiments. 10 is a flowchart showing a process in which a control unit according to a second embodiment stores information in a drum memory. 10 is a flowchart showing a life determination process in the second and third embodiments. 13 is a map of coefficients according to the state of the photosensitive drum in the third embodiment. 13 is a flowchart showing a process in which a control unit according to a third embodiment stores information in a drum memory. 13 is a flowchart showing a process in which a control unit according to a fourth embodiment stores information in a drum memory. 13 is a flowchart showing a lifespan determination process according to a fourth embodiment.

As shown in FIG. 1, the image forming device 1 is a color printer. The image forming device 1 includes a main body housing 10, a cover 11, a sheet supply unit 20, an image forming unit 30, a control unit 100, a main body memory 110, a temperature sensor TS, a main motor M1, a development motor M2, and a separation motor M3.

The main body housing 10 has a first opening 10A. The cover 11 is movable between a closed position shown by a solid line in which the first opening 10A is closed, and an open position shown by a two-dot chain line in which the first opening 10A is opened.

The sheet supply unit 20 is located at the bottom inside the main body housing 10. The sheet supply unit 20 includes a sheet tray 21 and a supply mechanism 22. The sheet tray 21 stores sheets S. The supply mechanism 22 supplies sheets S from the sheet tray 21 to the image forming unit 30. The sheet tray 21 is configured to be removable from inside the main body housing 10 to outside the main body housing 10. The supply mechanism 22 includes a paper feed roller 23, a separation roller 24, a separation pad 25, and a registration roller 27. The sheet S in this specification is a medium on which the image forming device 1 can form an image, and includes plain paper, envelopes, postcards, thin paper, thick paper, glossy paper, resin sheets, stickers, etc.

In the sheet supply unit 20, the feed roller 23 feeds the sheet S from the sheet tray 21. Then, the separation roller 24 and separation pad 25 separate the sheets S one by one. Next, the registration roller 27 regulates the leading edge position of the sheet S while the rotation is stopped. The registration roller 27 then rotates to supply the sheet S to the image forming unit 30.

The image forming unit 30 includes an exposure device 40, a drawer 90 which is an example of a drum cartridge, a number of developing cartridges 60, a conveying device 70, and a fixing unit 80.

The exposure device 40 has a laser diode, a deflector, a lens, and a mirror (not shown). The exposure device 40 is configured to emit multiple laser beams that expose the multiple photoconductor drums 50 and scan the surfaces of the photoconductor drums 50.

The drawer 90 has multiple photosensitive drums 50, developing cartridges 60, and a drum memory 98. In other words, the drawer 90 is used together with the developing cartridges 60. The developing cartridges 60 can be attached to or detached from the drawer 90.

The photoconductor drum 50 rotates about a first shaft 50X that extends in the axial direction of the photoconductor drum 50 (in the following description, the axial direction of the photoconductor drum 50 is simply referred to as the "axial direction"). A rotational driving force is input to the photoconductor drum 50 from the main motor M1.

The photosensitive drums 50 include a photosensitive drum 50Y corresponding to yellow, a photosensitive drum 50M corresponding to magenta, a photosensitive drum 50C corresponding to cyan, and a photosensitive drum 50K corresponding to black. In this specification and the drawings, the members provided corresponding to each color of yellow, magenta, cyan, and black are indicated with Y, M, C, and K, respectively, when the colors are to be distinguished.

The developing cartridge 60 has a developing roller 61. The developing roller 61 supplies toner to each photosensitive drum 50. Specifically, each developing cartridge 60Y, 60M, 60C, and 60K has a developing roller 61Y, 61M, 61C, and 61K corresponding to the photosensitive drums 50Y, 50M, 50C, and 50K of the Y, M, C, and K colors.

The temperature sensor TS is a sensor for measuring the internal temperature located near the photosensitive drum 50. In this embodiment, the temperature detected by the temperature sensor TS is used as the temperature of the photosensitive drum 50.

Developing roller 61Y, developing roller 61M, developing roller 61C, and developing roller 61K are arranged in this order from the upstream side to the downstream side in the movement direction of sheet S. Developing roller 61Y, developing roller 61M, developing roller 61C, and developing roller 61K. Developing roller 61 rotates about a second shaft 61X that extends in the axial direction.

Each developer cartridge 60 is movable between a contact position shown by a solid line in FIG. 1, where the developer roller 61 is in contact with the corresponding photosensitive drum 50, and a separation position shown by a two-dot chain line in FIG. 1, where the developer roller 61 is separated from the corresponding photosensitive drum 50.

As shown in FIG. 2, the photosensitive drum 50 is rotatably supported by a drawer 90. The drawer 90 also supports each developing cartridge 60 in a removable manner. The drawer 90 can be attached to or detached from the main body housing 10 through a first opening 10A that is formed by opening the cover 11 (see FIG. 1) of the main body housing 10. In this embodiment, the drawer 90 can be pulled out from the main body housing 10 to the outside.

The drawer 90 includes a side frame 91R, a side frame 91L, a connecting frame 92, and a connecting frame 93. The side frame 91R is positioned axially away from the side frame 91L. The connecting frame 92 connects one end of the side frame 91R to one end of the side frame 91L. The connecting frame 93 connects the other end of the side frame 91R to one end of the side frame 91L.
The drawer 90 has a charger 52 and a cleaning roller 53 (see FIG. 1 ). The charger 52 faces each photoconductor drum 50. The charger 52 charges the photoconductor drum 50. The cleaning roller 53 is in contact with the photoconductor drum 50. The cleaning roller 53 cleans the photoconductor drum 50.

Although detailed structural illustration is omitted, the side frames 91R and 91L support the ends of the photosensitive drum 50. The side frame 91L also has a second opening 91A. The second opening 91A is formed as a downwardly recessed notch on the upper edge of the side frame 91L. As a result, the second opening 91A penetrates the side frame 91L in the axial direction, allowing the cam follower 170, described below, to enter.

The image forming device 1 has a separation mechanism RK that switches between a contact state in which the outer circumferential surface of the developing roller 61 is in contact with the outer circumferential surface of the photosensitive drum 50 and a separation state in which the outer circumferential surface of the developing roller 61 is separated from the outer circumferential surface of the photosensitive drum 50.

The separation mechanism RK is a mechanism that switches the photosensitive drum 50 and the developing roller 61 between a contact state and a separated state by moving at least one of the photosensitive drum 50 or the developing roller 61.

In this embodiment, the separation mechanism RK moves each developing roller 61 between a contact position where it contacts the corresponding photosensitive drum 50 and a separation position where it is separated from the photosensitive drum 50. A separation mechanism RK is provided for each of the colors Y, M, C, and K.

Specifically, each separation mechanism RK has a support shaft 179, a cam gear 150 (150Y, 150M, 150C, 150K), a cam follower 170, a slide member 64, and a spring 176.

The support shaft 179 is a shaft that extends in the axial direction. The support shaft 179 is provided on a side frame (not shown) of the main body housing 10.

The cam gear 150 rotates about a rotation axis 150X that is parallel to the rotation axis 61X (see FIG. 1) of the developing roller 61. The cam gear 150 has a gear portion 150G, a disk portion 151, and an end cam 152.

The gear portion 150G is provided on the outer periphery of the disk portion 151. The gear portion 150G receives a driving force from the separation motor M3. The disk portion 151 has a substantially disk shape. The gear portion 150G receives a rotational driving force from the separation motor M3. As a result, the separation mechanism RK operates by the driving force from the separation motor M3.

The cam follower 170 is a member that is slidably supported on the support shaft 179 and slides in the axial direction by contacting the end face cam 152. Specifically, the cam follower 170 is guided by the end face cam 152 as the cam gear 150 rotates, and can slide between a first position shown in FIG. 4(b) and a second position shown in FIG. 4(a). When the cam follower 170 is located at the first position, the developing roller 61 is in a separated state. When the cam follower 170 is located at the second position, the developing roller 61 is in a contact state. The cam follower 170 has a sliding shaft portion 171, a contact portion 172, and a spring hook portion 174.

As shown in FIG. 2, the spring 176 is a tension spring. One end of the spring 176 is hooked to the spring hook portion 174. The other end of the spring 176 is hooked to a position on the drawer 90 that is lower than the spring hook portion 174. As a result, the spring 176 urges the cam follower 170 from the first position toward the second position. In this way, the spring 176 constantly presses the cam follower 170 against the end face cam 152.

The slide shaft portion 171 is a portion that engages with the support shaft 179. The contact portion 172 extends from the slide shaft portion 171. The axial end face of the contact portion 172 faces the end face cam 152 and can come into contact with the end face cam 152.

As shown in FIG. 3, the slide member 64 is a member that can slide in the axial direction relative to the case 63 of the developer cartridge 60. The slide member 64 can slide in the axial direction by being pressed by the cam follower 170.

As shown in Figures 4(a) and (b), the slide member 64 includes a shaft 191, a first abutment member 192, and a second abutment member 193. The first abutment member 192 is fixed to one end of the shaft 191, and the second abutment member 193 is fixed to the other end of the shaft 191.

The shaft 191 is disposed through an axially extending hole formed in the case 63 and is supported in the case 63 so that it can slide.

The first contact member 192 has a pressing surface 192A which is an end surface in the axial direction, and an inclined surface 192B which is inclined with respect to the axial direction.
The pressing surface 192A is a surface that is pressed by the cam follower 170 .
When the slide member 64 is pressed axially by the cam follower 170, the inclined surface 192B comes into contact with the contact portion 94 of the drawer 90 to urge the developer cartridges 60 (60Y, 60M, 60C, 60K) in a direction parallel to the moving direction of the sheet S, thereby moving the developer cartridges 60. As the inclined surface 192B moves from one end of the shaft 191 to the other end, it is inclined so as to be positioned in a direction from the photosensitive drum 50 toward the corresponding developer roller 61 in the second direction.

The second contact member 193 has an inclined surface 193B that is inclined similarly to the inclined surface 192B of the first contact member 192. When the slide member 64 is pressed axially by the cam follower 170, the inclined surface 193B also comes into contact with the contacted portion 94 of the drawer 90, and urges the developer cartridges 60 (60Y, 60M, 60C, 60K) in a direction parallel to the moving direction of the sheet S, thereby moving the developer cartridges 60.

A spring 194 is disposed between the first contact member 192 and the case 63 to bias the slide member 64 in one axial direction. The spring 194 is a compression coil spring, and is disposed outside the shaft 191 so that the shaft 191 passes through the coil. The spring 194 also functions as a spring that presses the cam follower 170 against the end cam 152 when the developing roller 61 is in a separated state.

The drawer 90 has contact portions 94 at the top of the side frames 91R and 91L that contact the slide members 64 described below. The contact portions 94 are, for example, rollers that can rotate around an axis along a third direction (vertical direction) that is perpendicular to both a first direction parallel to the axial direction of the photosensitive drums 50 and a second direction in which the photosensitive drums 50 are arranged.

The drawer 90 also includes a pressing member 95. The pressing member 95 is provided in the drawer 90 corresponding to each developer cartridge 60. The pressing member 95 is provided at both ends of the photosensitive drum 50 in the axial direction. The pressing member 95 is biased by a spring 95A (see Figures 4(a) and (b)). When the developer cartridge 60 is attached to the drawer 90, the pressing member 95 presses the protrusion 63D of the developer cartridge 60 to bring the developer roller 61 into contact with the corresponding photosensitive drum 50.

As shown in Figures 3(a) and (b), the developing cartridge 60 (60Y, 60M, 60C, 60K) has a case 63 that contains toner, a sliding member 64, and a coupling 65.

The case 63 has, on one side thereof, a first protruding portion 63A and a second protruding portion 63B as protruding portions that protrude in the axial direction.
The first protruding portion 63A is disposed coaxially with the rotation shaft 61X of the developing roller 61 and protrudes in the axial direction.
The second protrusion 63B is disposed at a predetermined distance from the first protrusion 63A. In this embodiment, the second protrusion 63B is disposed above the first protrusion 63A.
The first protruding portion 63A and the second protruding portion 63B are both rollers that can rotate around an axis that is parallel to the axial direction.
Although not shown, the case 63 has a first protrusion 63A and a second protrusion 63B on the other side surface at positions symmetrical to those on the one side surface.

The case 63 also has a protrusion 63D on the upper part of the front surface that is pressed by the pressing member 95. The protrusions 63D are provided on both ends of the case 63 in the axial direction.

The coupling 65 receives a rotational driving force from the development motor M2. The development roller 91 rotates in accordance with the rotation of the coupling 65.

5, the drawer 90 has a first support surface 96A and a second support surface 96B as support surfaces on the inner surface of one of the side frames 91L. The first support surface 96A and the second support surface 96B support the first protrusion 63A and the second protrusion 63B from below, respectively, when the first developing roller 61Y, the second developing roller 61M, the third developing roller 61C, and the fourth developing roller 61K move from the contact position to the separation position. The first support surface 96A and the second support surface 96B extend in the movement direction of the sheet S.
The first support surface 96A is disposed so as to support the first protruding portion 63A. The first support surface 96A serves both to guide the developing roller 61 when the developing cartridge 60 is attached to the drawer 90 and to position the developing roller 61 in the up-down direction.
The second support surface 96B is disposed above the first support surface 96A so as to support the second protrusion 63B.
Although not shown, the drawer 90 also has a first support surface 96A and a second support surface 96B on the inner surface of the other side frame 91R, which are symmetrical to the first support surface 96A and the second support surface 96B on the inner surface of the other side frame 91L.

When the developing roller 61 is in a contact position where it contacts the photosensitive drum 50, the first protrusion 63A is positioned toward the downstream side of the sheet movement direction on the first support surface 96A, as in the first developing cartridge 60Y, the second developing cartridge 60M and the third developing cartridge 60C in Figure 5.
On the other hand, when the developing roller 61 is in a separated position away from the photosensitive drum 50, the first protruding portion 63A is positioned upstream in the sheet movement direction on the first support surface 96A, as in the fourth developing cartridge 60K in FIG.
In this manner, when the separating mechanism RK moves each developing roller 61 from the contact position to the separated position, the separating mechanism RK moves the developing roller 61 from the downstream side to the upstream side in the moving direction of the sheet S.

Returning to FIG. 1, the conveying device 70 is provided between the sheet tray 21 and the photosensitive drums 50. The conveying device 70 includes a drive roller 71, a driven roller 72, a conveying belt 73 consisting of an endless belt, and four transfer rollers 74. The conveying belt 73 is stretched between the drive roller 71 and the driven roller 72, and its outer surface is arranged to face each photosensitive drum 50. Each transfer roller 74 is arranged inside the conveying belt 73 so as to sandwich the conveying belt 73 between each photosensitive drum 50. The conveying device 70 conveys the sheet S by moving the conveying belt 73 with the sheet S placed on the upper outer peripheral surface, and at this time, transfers the toner images of the multiple photosensitive drums 50 to the sheet S.

The fixing device 80 is provided downstream of the photoconductor drum 50 and the transport device 70 in the sheet movement direction. The fixing device 80 includes a heating roller 81 and a pressure roller 82 arranged opposite the heating roller 81. A transport roller 15 is provided above the fixing device 80, and a discharge roller 16 is provided above the transport roller 15.

In the image forming unit 30 configured in this manner, the surface of each photoconductor drum 50 is first uniformly charged by the charger 52, and then exposed to light emitted from the exposure device 40. This forms an electrostatic latent image based on image data on each photoconductor drum 50.

The toner in the case 63 is carried on the surface of the developing roller 61, and when the developing roller 61 comes into contact with the photosensitive drum 50, it is supplied to the electrostatic latent image formed on the photosensitive drum 50. This forms a toner image on the photosensitive drum 50.

Next, the sheet S fed onto the conveyor belt 73 passes between each photosensitive drum 50 and each transfer roller 74, so that the toner image formed on each photosensitive drum 50 is transferred onto the sheet S. Then, the sheet S passes between the heating roller 81 and the pressure roller 82, so that the toner image transferred onto the sheet S is thermally fixed onto the sheet S.

The sheet S discharged from the fixing unit 80 is accumulated in the discharge tray 13 on the top surface of the main body housing 10 by the transport rollers 15 and discharge rollers 16.

As shown in FIG. 6, the control unit 100 has a CPU 101, a RAM 102, a ROM 103, an EEPROM 104, and an input/output circuit. The control unit 100 executes printing control by performing calculations based on information about the installed cartridge and programs and data stored in the RAM 102, ROM 103, etc. The RAM 102 and EEPROM 104 are examples of the main memory 110. The RAM 102 is an example of a volatile memory. The EEPROM 104 is an example of a non-volatile memory. The CPU 101 is electrically connected to the RAM 102, ROM 103, and EEPROM 104.

The control unit 100 is electrically connected to the temperature sensor TS, the drum memory 98, the main motor M1, and the development motor M2. The main motor M1 drives the photosensitive drum 50 via a gear train (not shown). The development motor drives the development roller 61 and the separation mechanism RK via a gear train and clutch (not shown). Note that in FIG. 6, the transmission of electrical signals is indicated by solid lines, and the transmission of driving force is indicated by dashed lines.

The control unit 100 can obtain the temperature detected by the temperature sensor TS. The control unit 100 can read data from the drum memory 98 and can write data thereto.
The control unit 100 can count the number of rotations of the main motor M1. As a result, the control unit 100 can calculate the number of rotations of the photosensitive drum 50 based on the counted number of rotations of the main motor M1 and the gear ratio. The gear ratio is the gear ratio between the output gear of the main motor M1 and the input gear of the photosensitive drum 50, and is stored in, for example, the EEPROM 104.
The control unit 100 can count the number of rotations of the developing motor M2. As a result, the control unit 100 can calculate the number of rotations of the developing roller 61 based on the counted number of rotations of the developing motor M2 and the gear ratio. Note that the gear ratio is the gear ratio between the output gear of the developing motor M2 and the input gear of the developing roller 61, and is stored in the EEPROM 104, for example.

The control unit 100 counts the first number of rotations, which is the number of times the photoconductor drum 50 rotates in a contact state. The control unit 100 counts the second number of rotations, which is the number of times the photoconductor drum 50 rotates in a separated state. The control unit 100 determines the amount of wear W due to the rotation of the photoconductor drum 50 based on the first number of rotations and the second number of rotations. The control unit 100 then calculates the life of the photoconductor drum 50 from the amount of wear W of the photoconductor drum 50. Below, the method of calculating the amount of wear W of the photoconductor drum 50 and the life and remaining life of the photoconductor drum 50 for the first embodiment will be specifically described.

The control unit 100 counts the number of rotations of the main motor M1 from when it is turned on to when it is turned off. The number of rotations of the main motor M1 counted by the control unit 100 is written in the RAM 102 one by one.
The control unit 100 calculates the number of rotations of the photosensitive drum 50 from the number of rotations of the main motor M1. The number of rotations of the photosensitive drum 50 calculated by the control unit 100 is written in the RAM 102 one by one.
The control unit 100 _counts the first number of rotations _xm and the second number of rotations yn in a predetermined period separately by determining whether the main motor M1 is in a contact state or a separated state when the main motor M1 is turned on. The first number of rotations _xm and the second number of rotations _yn are written to the RAM 102 one by one.

The control unit 100 stores the counted first and second rotation counts in the drum memory 98. As shown in FIG. 7, the drum memory 98 has a first storage area 98A and a second storage area 98B.

The first storage area 98A stores a first rotation count. In this embodiment, the first storage area 98A stores a first total rotation count X as the first rotation count. The first total rotation count X is the cumulative number of times the photoconductor drum 50 has rotated in a contact state from when the photoconductor drum 50 is brand new ( _x1 + _x2 + _x3 + ... + _xm ). That is, the first storage area 98A is overwritten and stored with the first total rotation count X every time the photoconductor drum 50 rotates in a contact state.

The second storage area 98B stores the second number of rotations. In this embodiment, the second storage area 98B stores a second total number of rotations Y as the second number of rotations. The second total number of rotations Y is the cumulative number of times the photoconductor drum 50 has rotated in a separated state from a state in which the photoconductor drum 50 is brand new ( _y1 + _y2 + _y3 + ... + _yn ). That is, the second total number of rotations Y is overwritten and stored in the second storage area 98B every time the photoconductor drum 50 rotates in the separated state.

When the control unit 100 calculates the wear amount of the photosensitive drum 50, it reads the first total number of rotations X and the second total number of rotations Y from the drum memory 98 and the RAM 102 of the main body memory 110. Then, the control unit 100 calculates the wear amount W of the photosensitive drum 50 based on the first total number of rotations X and the second total number of rotations Y stored in the RAM 102. Specifically, the control unit 100 calculates the wear amount W of the photosensitive drum 50 as the sum of the number obtained by multiplying the first total number of rotations X by the first coefficient a and the number obtained by multiplying the second total number of rotations Y by the second coefficient b (W = aX + bY). The second coefficient b is a number smaller than the first coefficient a. Note that the first coefficient a and the second coefficient b are positive numbers and are values obtained from experimental data before the shipment of the image forming device 1. The first coefficient a and the second coefficient b are pre-stored in the drum memory 98 or the main memory 110 (e.g., EEPROM 104).

When the wear amount W of the photoconductor drum 50 reaches a threshold value, the control unit 100 determines that the photoconductor drum 50 has reached the end of its life. The threshold value for determining the end of its life is stored in advance in the drum memory 98 or the main body memory 110 (e.g., EEPROM 104).

The control unit 100 calculates the remaining life of the photoconductor drum 50 by subtracting the wear amount W of the photoconductor drum 50 from the life of the photoconductor drum 50. For example, the calculated remaining life is displayed on a display unit (not shown) of the image forming device 1.

Next, an example of the process of the first embodiment executed by the control unit 100 will be described with reference to the flowchart in FIG. 8. The control unit 100 repeatedly executes this process for each of the four photoconductor drums 50 while the power of the image forming apparatus 1 is ON.

As shown in FIG. 8, the control unit 100 determines whether the main motor M1 is turned on (S1). If the control unit 100 does not determine that the main motor M1 is turned on (S1, No), the control unit 100 waits until the main motor M1 is turned on.

In step S1, if the control unit 100 determines that the main motor M1 is turned on (S1, Yes), it determines whether the photosensitive drum 50 is in a contact state (S2).

In step S2, when the control unit 100 determines that the photoconductor drum 50 is in a contact state (S2, Yes), it counts the first number of rotations _xm of the photoconductor drum 50 for a predetermined period (S3). The first number of rotations _xm is written sequentially to the RAM 102. The predetermined period may be a fixed time, may be the time for one print job, or may be a period during which the photoconductor drum 50 rotates a predetermined number of times.

After step S3, the first rotation number _xm for the predetermined period is added to the first total rotation number X stored in the first storage area 98A of the drum memory 98 to update the first total rotation number X (S4).

After step S4, the control unit 100 determines whether there has been a change in the contact or separation state of the photoconductor drum 50 before and after the specified period has elapsed (S5).

In step S5, when the control unit 100 determines that there has been a change in the contact or separation state of the photoconductor drum 50 (S5, Yes), the control unit 100 proceeds to step S2.
On the other hand, in step S5, when the control unit 100 determines that there has been no change in the contact or separation state of the photosensitive drum 50 (S5, No), the control unit 100 determines whether to turn off the main motor M1 (S6).

If the control unit 100 does not determine in step S6 that the main motor M1 should be turned OFF (S6, No), the process proceeds to step S3. On the other hand, if the control unit 100 determines in step S6 that the main motor M1 should be turned OFF (S6, Yes), the process ends.

In step S2, if the control unit 100 does not determine that the photosensitive drum 50 is in a contact state (S2, No), that is, if the photosensitive drum 50 is in a separated state, it _counts the second number of rotations yn of the photosensitive drum 50 for a predetermined period of time (S7).

After step S7, the second rotation count _yn for the predetermined period is added to the second total rotation count Y stored in the second storage area 98B of the drum memory 98 to update the second total rotation count Y (S8).

After step S8, the control unit 100 determines whether there has been a change in the contact or separation state of the photoconductor drum 50 before and after the specified period has elapsed (S9).

In step S9, when the control unit 100 determines that there has been a change in the contact or separation state of the photoconductor drum 50 (S9, Yes), the control unit 100 proceeds to step S2.
On the other hand, in step S9, when the control unit 100 determines that there has been no change in the contact or separation state of the photosensitive drum 50 (S9, No), the control unit 100 determines whether to turn off the main motor M1 (S10).

If the control unit 100 does not determine in step S10 that the main motor M1 should be turned OFF (S10, No), the process proceeds to step S7. On the other hand, if the control unit 100 determines in step S10 that the main motor M1 should be turned OFF (S10, Yes), the process ends.

Next, an example of the lifespan determination process in the first embodiment executed by the control unit 100 will be described with reference to the flowchart in FIG. 9. The control unit 100 repeatedly executes the lifespan determination process for each of the four photoconductor drums 50 while the image forming apparatus 1 is powered on.

As shown in FIG. 9, when executing the lifespan determination process, the control unit 100 reads the first total number of rotations X and the second total number of rotations Y from the drum memory 98 to the RAM 102 (S11).

After step S11, the control unit 100 calculates the wear amount W of the photoconductor drum 50 by adding the first total number of rotations X read into the RAM 102 multiplied by the first coefficient a and the second total number of rotations Y read into the RAM 102 multiplied by the second coefficient b (W = aX + bY) (S12).

After step S12, the control unit 100 determines whether the calculated consumption amount W is equal to or greater than a threshold value (S13).

In step S13, when the control unit 100 determines that the calculated wear amount W is equal to or greater than the threshold value (S13, Yes), it determines that the photoconductor drum 50 has reached the end of its life (S14), and ends the process.
On the other hand, in step S13, if the control unit 100 does not determine that the calculated wear amount W is equal to or greater than the threshold value (S13, No), the control unit 100 does not determine that the photoconductor drum 50 has reached the end of its life and ends the process.

According to the above-described embodiment, the drum memory 98 stores the first rotation count in the first storage area 98A and the second rotation count in the second storage area, so that the rotation count in the contact state and the rotation count in the separated state can be stored separately in the drum memory 98. If the amount of wear is calculated based on the first rotation count and the second rotation count, the drum cartridge 50 can accurately calculate the amount of wear of the photosensitive drum 50.
By providing such a drum cartridge 50, the control unit 100 of the image forming apparatus 1 is able to calculate the amount of wear W of the photosensitive drum 50 based on the first total number of rotations X and the second total number of rotations Y.

Fig. 10 is a graph showing the relationship between the total number of rotations of the photoconductor drum 50 calculated by the control unit 100 and the wear amount W of the photoconductor drum 50. In Fig. 10, the solid line shows the calculation according to the present embodiment, and the dashed line shows the calculation according to the conventional technology.
In the conventional technology, the amount of wear when the developing roller 61 is separated from the photosensitive drum 50 is not taken into consideration, and only the amount of wear when the developing roller 61 is in contact with the photosensitive drum 50 is counted.
In contrast, in this embodiment, the wear amount W is calculated by distinguishing between the first rotation count _xm , which is the contact state, and the second rotation count _yn , which is the separated state. Specifically, the second rotation count _yn , which is the separated state, is multiplied by a second coefficient b, which is smaller than the first coefficient a. This makes it possible to accurately calculate the wear amount W of the photoconductor drum 50.

Next, a second embodiment will be described.
In the first embodiment, the wear amount W of the photoconductor drum 50 is calculated separately for the two states of the photoconductor drum 50 being in contact and in a separated state, whereas in the second embodiment, the wear amount W of the photoconductor drum 50 is calculated using a coefficient according to the temperature of the photoconductor drum 50 when it is rotating in addition to the state of the photoconductor drum 50 being in contact or separated, which is different from the first embodiment. That is, in the second embodiment, the wear amount W is calculated by changing the first coefficient a _m and the second coefficient b _n according to the temperature of the photoconductor drum 50 when it is rotating.

The control unit 100 determines the first coefficient a _m and the second coefficient b _n based on the temperature of the photoconductor drum 50 acquired from the temperature sensor TS. The first coefficient a _m and the second coefficient b _n are values that change based on the temperature of the photoconductor 50. The first coefficient a _m and the second coefficient b _n may become smaller or larger as the temperature of the photoconductor drum 50 acquired from the temperature sensor TS increases, depending on the materials of the photoconductor drum 50 and the cleaning roller 53. Here, as an example, a case will be described in which the first coefficient a _m and the second coefficient b _n become smaller as the temperature of the photoconductor drum 50 acquired from the temperature sensor TS increases. That is, the control unit 100 determines the first coefficient a _m and the second coefficient b _n so that the higher the temperature acquired from the temperature sensor TS becomes, the smaller the value becomes. In other words, the first coefficient _{a_m} and the second coefficient _{b_n} are values that are determined to be smaller as the temperature of the photoconductor drum 50 when the photoconductor drum 50 is rotated increases.

To determine the first coefficient a _m and the second coefficient b _n , for example, a map of coefficients according to the temperature of the photoconductor drum 50 and the contact or separation state shown in Fig. 11 may be used. The map of coefficients is stored in, for example, the drum memory 98 or the EEPROM 104.
11, when the acquired temperature is high, the first coefficient a _m is set to a _H , when the acquired temperature is medium, it is set to a _M , and when the acquired temperature is low, it is set to a _L. Similarly, when the acquired temperature is high, the second coefficient b _n is set to b _H , when the acquired temperature is medium, it is set to b _M , and when the acquired temperature is low, it is set to b _L.
As an example, high temperature is equal to or higher than 30° C., medium temperature is equal to or higher than 10° C. and lower than 30° C., and low temperature is lower than 10° C. Furthermore, the coefficients satisfy the relationships _{aH <} aM<aL, bH< _bM <bL, aH> _bH , _aM >bM, and _aL > _bL .

12, the control unit 100 stores a first rotation count _xm during a predetermined period and a first coefficient am corresponding to the first rotation count _xm in a first storage area _98A of the drum memory 98. In other words, the first storage area 98A stores the first coefficient _am corresponding to the first rotation count _xm in addition to the first rotation count _xm .
Similarly, the second rotation count _yn and the second coefficient _bn corresponding to the second rotation count _yn are stored in the second storage area 98B of the drum memory 98. In other words, the second storage area 98B stores the second rotation count _yn , as well as the second coefficient _bn corresponding to the second rotation count _yn .

The control unit 100 reads out all of the first rotation count _xm , the first coefficient _am , the second rotation count _yn , and the second coefficient _bn into the main memory 110 (e.g., RAM 102), and calculates the wear amount _W of the photoconductor drum _{50 by adding together the cumulative number of times the first rotation count xm multiplied by the first coefficient am and} the cumulative number of times the first rotation count xm multiplied by the second coefficient _bn (W=Σa _{m xm} +Σb _{ny n} ). In other words, the wear amount W of the photoconductor drum 50 worn down by the rotation of the photoconductor drum 50 is determined by adding together the cumulative number of times the first rotation count _xm multiplied by the first coefficient _am and the cumulative number of times the second rotation count yn multiplied by the second coefficient _bn , which is smaller _than the first coefficient _am .

Next, an example of the processing executed by the control unit 100 in the second embodiment will be described with reference to the flowchart in FIG. 13.

As shown in FIG. 13, the control unit 100 determines whether the main motor M1 is turned on (S21). If the control unit 100 does not determine that the main motor M1 is turned on (S21, No), the control unit 100 waits until the main motor M1 is turned on.

In step S21, if the control unit 100 determines that the main motor M1 is turned on (S21, Yes), it determines the first coefficient a _m or the second coefficient b _n depending on the contact or separation state of the photoconductor drum 50 and the obtained temperature (S22).

After step S22, the control unit 100 counts the number of rotations of the photoconductor drum 50 for a predetermined period (S23). The number of rotations at this time is either a first number of rotations x _m or a second number of rotations y _n depending on the contact or separation state of the photoconductor drum 50.

After step S23, the control unit 100 stores the first rotation number _xm and the first coefficient _am , or the second rotation number _yn and the second coefficient _bn , in the drum memory 98 (S24).

After step S24, the control unit 100 performs the following before and after the predetermined period has elapsed:
It is determined whether there is a change in at least one of the contact or separation state of the photoconductor drum 50 and the acquired temperature (S25). Note that a change in the acquired temperature refers to a change from a high, medium, or low temperature state to another state (see FIG. 11). That is, in step S25, the control unit 100 determines whether or not to change the coefficient.

If the control unit 100 determines in step S25 that there is a change in at least one of the contact or separation state of the photoconductor drum 50 and the acquired temperature (S25, Yes), it proceeds to step S22. On the other hand, if the control unit 100 does not determine in step S25 that there is a change in at least one of the contact or separation state and the acquired temperature (S25, No), it determines whether to turn off the main motor M1 (S26).

If the control unit 100 does not determine in step S26 that the main motor M1 should be turned OFF (S26, No), the process proceeds to step S23. On the other hand, if the control unit 100 determines in step S26 that the main motor M1 should be turned OFF (S26, Yes), the process ends.

Next, an example of the lifespan determination process executed by the control unit 100 in the second embodiment will be described with reference to the flowchart in FIG. 14.

As shown in FIG. 14, when executing the life determination process, the control unit 100 reads out the first rotation count x _m , the first coefficient a _m , the second rotation count y _n , and the second coefficient b _n from the drum memory 98 (S31).

After step S31, the control unit 100 calculates the wear amount W of the photoconductor drum 50 by adding the cumulative number obtained by multiplying the first rotation count _xm by the first coefficient _am to the cumulative number _obtained by multiplying the first rotation count xm by the second coefficient _bn (W = Σa _m x _m + Σb _{ny n} ) (S32).

After step S32, the control unit 100 determines whether the calculated consumption amount W is equal to or greater than a threshold value (S33).

In step S33, when the control unit 100 determines that the calculated wear amount W is equal to or greater than the threshold value (S33, Yes), it determines that the photoconductor drum 50 has reached the end of its life (S34), and ends the process.
On the other hand, in step S33, if the control unit 100 does not determine that the calculated wear amount W is equal to or greater than the threshold value (S33, No), the control unit 100 does not determine that the photoconductor drum 50 has reached the end of its life and ends the process.

According to the second embodiment described above, the wear amount W of the photosensitive drum 50 is calculated based on the contact or separation state, as well as based on the first coefficient a _m corresponding to the first rotation count x _m and the second coefficient b _n corresponding to the second rotation count _yn , so that the wear amount W can be calculated according to the state when the photosensitive drum 50 is rotating.

For example, the amount of wear W due to the rotation of the photosensitive drum 50 differs depending on the temperature of the photosensitive drum 50. For example, if the lower the temperature of the photosensitive drum 50, the more easily the photosensitive drum 50 is abraded, then the higher the temperature of the photosensitive drum 50, the smaller the amount of wear W due to rotation. On the other hand, if the higher the temperature of the photosensitive drum 50, the more easily the photosensitive drum 50 is abraded, then the higher the temperature of the photosensitive drum 50, the greater the amount of wear W due to rotation. Note that the relationship between the ease of abrasion of the photosensitive drum 50 and the temperature differs depending on the constituent materials of the photosensitive drum 50 and the cleaning roller 53, etc.
To address this issue, in the second embodiment, the amount of wear W is calculated based on the state of contact or separation, as well as on the temperature of the photosensitive drum 50 when the photosensitive drum 50 rotates, so that the amount of wear W of the photosensitive drum 50 can be calculated with high accuracy.

Next, a third embodiment will be described.
In the second embodiment, the wear amount W of the photosensitive drum 50 was calculated using a coefficient depending on the temperature of the photosensitive drum 50 in addition to the contact or separation state of the photosensitive drum 50. In the third embodiment, however, the wear amount W of the photosensitive drum 50 is calculated using a coefficient depending on the total number of rotations Z of the photosensitive drum 50 in addition to the contact or separation state and temperature of the photosensitive drum 50.

The total number of rotations Z of the photosensitive drum 50 is calculated by adding the first total number of rotations X and the second total number of rotations Y (Z=X+Y). When the total number of rotations Z=0, the photosensitive drum 50 is brand new, and the larger the total number of rotations Z, the closer the photosensitive drum 50 is to the end of its life.

Specifically, the control unit 100 determines the first coefficient a _{m and the second coefficient b n so that the first coefficient a m} and the second coefficient b _n become larger as the total number of rotations Z of the photoconductor drum 50 since the photoconductor drum 50 is brand new increases. In other words, the first coefficient a _m and the second coefficient b _n are values that are determined to become larger as the total number of rotations Z of the photoconductor drum 50 since the photoconductor drum 50 is brand new increases.

To determine the first coefficient a _m and the second coefficient b _n , for example, a map shown in FIG. 15 may be used.
As shown in FIG. 15, when the contact state is established and the total number of rotations Z is small, the first coefficient a _m is set to a _HS when the acquired temperature is high, a _MS when the acquired temperature is medium, and a _LS when the acquired temperature is low.
In the case of contact and the total number of rotations Z being normal, when the acquired temperature is high, the first coefficient a _m is set to a _HF , when it is medium temperature, a _MF , and when it is low, a _LF .
In the case of a contact state and a large total number of rotations Z, when the acquired temperature is high, the first coefficient a _m is set to a _HO , when the acquired temperature is medium, a _MO , and when the acquired temperature is low, a _LO .

Similarly, in the case of the separated state and the total number of rotations Z being small, when the acquired temperature is high, the second coefficient _bn is set to _bHS , when it is medium temperature, _aMS , and when it is low, _bLS .
In the case of contact and the total number of rotations Z being normal, when the acquired temperature is high, the second coefficient _bn is set to _bHF , when it is medium temperature, it is set to _bMF , and when it is low, it is set to _bLF .
In the case of a contact state and a large total number of rotations Z, when the acquired temperature is high, the second coefficient _bn is set to _bHO , when the acquired temperature is medium, _bMO , and when the acquired temperature is low, _bLO .

As an example, a low total rotation count Z is less than 10,000 rotations from a new state, a normal total rotation count Z is between 10,000 and 20,000 rotations, and a high total rotation count Z is 20,000 rotations or more.
In addition, each coefficient is, for example,
a _HS < a _MS < a _LS , a _HF < a _MF < a _LF , a _HO < a _MO < a _LO ,
a _HS <a _HF <a _HO , a _MS <a _MF <a _MO , a _LS <a _LF <a _LO ,
b _HS < b _MS < b _LS , b _HF < b _MF < b _LF , b _HO < b _MO < b _LO ,
The relationships _bHS < _bHF < _bHO , _bMS < _bMF < _bMO , and _bLS < _bLF < _bLO are satisfied.

Next, an example of the processing executed by the control unit 100 in the third embodiment will be described with reference to the flowchart in FIG. 16.

As shown in FIG. 16, the control unit 100 determines whether the main motor M1 is turned on (S41). If the control unit 100 does not determine that the main motor M1 is turned on (S41, No), the control unit 100 waits until the main motor M1 is turned on.

In step S41, if the control unit 100 determines that the main motor M1 is turned on (S41, Yes), it determines the first coefficient a _m or the second coefficient b _n according to the contact or separation state of the photosensitive drum 50, the obtained temperature, and the total number of rotations Z of the photosensitive drum 50 (S42).

After step S42, the control unit 100 counts the number of rotations of the photoconductor drum 50 for a predetermined period (S43). The number of rotations at this time is either a first number of rotations x _m or a second number of rotations y _n depending on the contact or separation state of the photoconductor drum 50.

After step S43, the control unit 100 stores the first rotation number _xm and the first coefficient _am , or the second rotation number _yn and the second coefficient _bn , in the drum memory 98 (S44).

After step S44, the control unit 100 performs the following before and after the predetermined period has elapsed:
It is determined whether there is a change in at least one of the contact/separation state of the photoconductor drum 50 and the acquired temperature (S45). Note that a change in the acquired temperature refers to a change from a high, medium, or low temperature state to another state (see FIG. 15). That is, in step S45, the control unit 100 determines whether or not to change the coefficient.

In step S45, if the control unit 100 determines that there is a change in at least one of the contact or separation state of the photoconductor drum 50 and the acquired temperature (S45, Yes), it proceeds to step S42.

On the other hand, in step S45, if the control unit 100 does not determine that there has been a change in at least one of the contact/separation state of the photoconductor drum 50 and the acquired temperature (S45, No), it determines whether the total number of rotations Z has exceeded a predetermined value (S46). The total number of rotations Z exceeds the predetermined value when the total number of rotations Z changes from "low" to "normal" or when the total number of rotations Z changes from "normal" to "high" (see FIG. 15). That is, in step S46, the control unit 100 determines whether to change the coefficient.

If the control unit 100 determines in step S46 that the total number of rotations Z has exceeded the predetermined value (S46, Yes), it proceeds to step S42. On the other hand, if the control unit 100 does not determine in step S46 that the total number of rotations Z has exceeded the predetermined value (S46, No), it determines whether to turn off the main motor M1 (S47).

If the control unit 100 does not determine in step S47 that the main motor M1 should be turned OFF (S26, No), the process proceeds to step S43. On the other hand, if the control unit 100 determines in step S47 that the main motor M1 should be turned OFF (S46, Yes), the process ends.

The life determination process performed by the control unit 100 in the third embodiment is the same as in the second embodiment (see Figure 14).

According to the third embodiment described above, the wear amount W of the photosensitive drum 50 is calculated based on the contact or separation state of the photosensitive drum 50 and the temperature of the photosensitive drum, as well as based on the total number of rotations Z of the photosensitive drum 50, so that the wear amount W of the photosensitive drum 50 can be calculated with high accuracy.

Next, a fourth embodiment will be described.
In the first embodiment, the control unit 100 stores the first total number of rotations X and the second total number of rotations Y of the photosensitive drum 50 in the drum memory 98, whereas in the fourth embodiment, the control unit 100 stores the amount of wear W of the photosensitive drum 50 in the drum memory 98, which is different from the first embodiment.

Specifically, the control unit 100 stores the wear amount W of the photosensitive drum 50 in the drum memory 98. When the photosensitive drum 50 is new, the wear amount W = 0.

When the photoconductor drum 50 is rotated for a predetermined period, the control unit 100 counts the number of rotations z _n during the predetermined period. The control unit 100 determines a coefficient α _n according to the contact or separation state of the photoconductor drum 50, the acquired temperature, and the total number of rotations Z of the photoconductor drum 50 when the number of rotations z _n is counted. The coefficient α _n is a first coefficient a _m or a second coefficient b _n according to the contact or separation state of the photoconductor drum 50. To determine the coefficient α _n , it is advisable to use the map shown in FIG. 15 as in the third embodiment.

When the control unit 100 rotates the photoconductor drum 50 , it adds a number obtained by multiplying the number of rotations z _n and the coefficient α _n to the consumption amount W, and stores the result in the drum memory 98 as a new consumption amount W.

Next, an example of the processing of the fourth embodiment executed by the control unit 100 will be described with reference to the flowchart in FIG. 17.

As shown in FIG. 17, the control unit 100 determines whether the main motor M1 is turned on (S51). If the control unit 100 does not determine that the main motor M1 is turned on (S51, No), the control unit 100 waits until the main motor M1 is turned on.

In step S51, if the control unit 100 determines that the main motor M1 is turned on (S51, Yes), it determines the coefficient _αn according to the contact or separation state of the photosensitive drum 50, the obtained temperature, and the total number of rotations Z of the photosensitive drum 50 (S52).

After step S52, the control unit 100 counts the number of rotations _zn of the photoconductor drum 50 for a predetermined period (S53).

After step S53, the control unit 100 updates the wear amount W of the photosensitive drum 50 stored in the drum memory 98 by adding the _value obtained by multiplying the coefficient _αn by the number of rotations _zn to the wear amount W, and stores the updated wear amount W in the drum memory 98 (W←W+ _αnzn ) (S54).

After step S54, it is determined whether to turn off the main motor M1 (S55).

If the control unit 100 does not determine in step S55 that the main motor M1 should be turned OFF (S55, No), the process proceeds to step S53. On the other hand, if the control unit 100 determines in step S55 that the main motor M1 should be turned OFF (S55, Yes), the process ends.

Next, an example of the lifespan determination process executed by the control unit 100 in the fourth embodiment will be described with reference to the flowchart in FIG. 18.

As shown in FIG. 18, when performing the lifespan determination process, the control unit 100 reads the wear amount W from the drum memory 98 (S61).

After step S61, the control unit 100 determines whether the consumption amount W is equal to or greater than the threshold value (S62).

In step S62, when the control unit 100 determines that the wear amount W is equal to or greater than the threshold value (S62, Yes), it determines that the photoconductor drum 50 has reached the end of its life (S63), and ends the process.
On the other hand, in step S62, when the control unit 100 does not determine that the wear amount W is equal to or greater than the threshold value (S62, No), the control unit 100 does not determine that the photoconductor drum 50 has reached the end of its life and ends the process.

In the above-described fourth embodiment, the drum cartridge 50 stores the wear amount W of the photosensitive drum 50 in the drum memory 98, which is determined based on the number of rotations in the contact state (first number of rotations x _m ) and the number of rotations in the separated state (second number of rotations y _n ), so that the wear amount W of the photosensitive drum 50 can be accurately calculated.
Therefore, the control unit 100 of the image forming apparatus 1 calculates the amount of wear W based on the contact or separation state of the photosensitive drum 50 and the temperature of the photosensitive drum, as well as the total number of rotations Z of the photosensitive drum 50, so that the amount of wear W of the photosensitive drum 50 can be calculated with high accuracy.

Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments and can be modified as appropriate.

In the second, third and fourth embodiments described above, a map of the state of the photoconductor drum 50 and the coefficients corresponding to the state is used to determine the first coefficient a _m and the second coefficient b _n , but this is not limited to this, and the coefficients may be determined by a calculation formula.

For example, when the photoconductor drum 50 is in a contact state, the coefficient _αn may be a value obtained by adding the first constant _a0 multiplied by the first correction coefficient _c1 and the total number of rotations Z ( _αn = _a0 + _c1Z ). Similarly, when the photoconductor drum 50 is in a separated state, the coefficient _αn may be a value obtained by adding the second constant _b0 multiplied by the second correction coefficient _c2 and the total number of rotations Z ( _αn = _b0 + _c2Z ). The first correction coefficient _c1 and the second correction coefficient _c2 are positive values.

The control unit 100 can calculate the amount of wear W of the photoconductor drum 50 by accumulating the number of rotations _zn of the photoconductor drum 50 multiplied by a coefficient _αn during a predetermined period (W= _Σαn · _zn ).
Alternatively, the control unit 100 can store the consumption amount W in the drum memory 98, and when the photosensitive drum 50 is rotated, can add the product of the number of rotations z _n and a coefficient α _n corresponding to the number of rotations z _n to the consumption amount W and store the result in the drum memory 98 as a new consumption amount W.

In the above embodiment, a map of three temperature categories, high, medium, and low, was used to determine each coefficient, but the number of temperature categories may be two or four or more.

In the above embodiment, a map with three categories of total rotation count Z, "low," "normal," and "high," was used to determine each coefficient, but the number of categories may be two or four or more.

In the above embodiment, the contact or separation state of the photoconductor drum 50, the temperature of the photoconductor drum 50, and the total number of rotations Z are used to determine each coefficient, but the present disclosure is not limited to this.
For example, if the image forming apparatus is equipped with a cleaning roller 53 that can move between a contact position in contact with the photosensitive drum 50 and a separation position away from the photosensitive drum 50, the coefficient may be determined based on the contact or separation state of the cleaning roller 53.
Furthermore, if the image forming device is equipped with a charging roller instead of the charger 52 and the charging roller is movable between a contact position where it contacts the photosensitive drum 50 and a separation position where it is separated from the photosensitive drum 50, the coefficient may be determined based on the contact or separation state of the charging roller.

In the above embodiment, the separation mechanism RK switches between the contact state and the separation state by moving the developing roller 61, but the separation mechanism RK may also switch between the contact state and the separation state by moving the photosensitive drum 50, or may switch between the contact state and the separation state by moving both the developing roller 61 and the photosensitive drum 50.

In the third embodiment described above, the wear amount W of the photosensitive drum 50 was calculated using a coefficient corresponding to the temperature of the photosensitive drum 50 and the total number of rotations Z of the photosensitive drum 50. However, the wear amount W may be calculated using a coefficient that is not dependent on the temperature of the photosensitive drum 50 but is dependent on the total number of rotations Z.

In addition, in the above embodiment, the motor that drives the photosensitive drum 81 and the motor that drives the developing roller 91 are the same, but the motor that drives the photosensitive drum 81 and the motor that drives the developing roller 91 may be separate.

In addition, in the above-described embodiment, the drum cartridge is a drawer that can be pulled out from the main body housing and has four photosensitive drums and four installable or removable developing cartridges, but this is not limited to this form.
For example, the drum cartridge is not limited to a configuration having a plurality of developing cartridges and a plurality of photosensitive drums, and may be a configuration having one developing cartridge and one photosensitive drum.
Also, for example, the drum cartridge is configured to be able to be pulled out from the main body housing, but it may be configured to be able to be attached to or detached from the main body housing from above or at an angle.
Also, for example, the drum cartridge is configured such that a developing cartridge having a developing roller can be attached or detached, but it may be configured such that a toner cartridge without a developing roller can be attached or detached. In this case, the drum cartridge has a developing roller and a photosensitive drum. Also, the toner cartridge does not have a developing roller, but has a toner storage section that stores toner.
In addition, for example, the developing cartridge is mountable or detachable from the drum cartridge, and the drum cartridge with the developing cartridge mounted thereon is mountable or detachable from the main body housing, but the developing cartridge and the drum cartridge may be mountable or detachable from the main body housing separately. Also, the developing cartridge may be mounted or detachable from the main body housing as an integrated drum cartridge in which the developing cartridge cannot be removed separately from the drum cartridge. In this case, the drum cartridge has a toner storage section that stores toner, a developing roller, and a photosensitive drum.

In addition, in the above embodiment, an image forming device 1 that prints color images using four color toners is exemplified, but the image forming device may be one that can only print in monochrome, or may be a device that prints color images using three or five or more color toners.

The image forming device may also be a multifunction device or a copier.

The elements of each of the above-mentioned embodiments and variations can be implemented in any combination.

REFERENCE SIGNS LIST 1 Image forming apparatus 10 Main body housing 50 Photoconductor drum 50X First shaft 60 Development cartridge 61 Development roller 61X Second shaft 90 Drawer 98 Drum memory 98A First storage area 98B Second storage area 100 Control unit

Claims (16)

A drum cartridge,
a photosensitive drum that rotates about a first axis extending in an axial direction, the photosensitive drum being in a contact state in which an outer circumferential surface of a developing roller is in contact with an outer circumferential surface of the photosensitive drum, or in a separated state in which an outer circumferential surface of the developing roller is separated from an outer circumferential surface of the photosensitive drum;
a drum memory having a first storage area for storing a first rotation count, which is the number of times the photosensitive drum has rotated in the contact state, and a second storage area for storing a second rotation count, which is the number of times the photosensitive drum has rotated in the separated state;
Equipped with
the first storage area stores, as the first rotation count, a first total rotation count that is an accumulation of the number of times that the photosensitive drum has rotated in the contact state since the photosensitive drum started to be used;
The drum cartridge is characterized in that the second memory area stores as the second rotation count a second total rotation count, which is the cumulative number of times the photosensitive drum has rotated in the separated state since the photosensitive drum began to be used. 2. The drum cartridge according to claim 1 , wherein the amount of wear of the photosensitive drum caused by rotation of the photosensitive drum is determined based on the first total number of rotations and the second total number of rotations. 3. The drum cartridge according to claim 2, wherein the amount of wear of the photosensitive drum caused by rotation of the photosensitive drum is determined by adding a number obtained by multiplying the first total number of rotations by a first coefficient and a number obtained by multiplying the second total number of rotations by a second coefficient smaller than the first coefficient. A drum cartridge,
a photosensitive drum that rotates about a first axis extending in an axial direction, the photosensitive drum being in a contact state in which an outer circumferential surface of a developing roller is in contact with an outer circumferential surface of the photosensitive drum, or in a separated state in which an outer circumferential surface of the developing roller is separated from an outer circumferential surface of the photosensitive drum;
a drum memory having a first storage area for storing a first rotation count, which is the number of times the photosensitive drum has rotated in the contact state, and a second storage area for storing a second rotation count, which is the number of times the photosensitive drum has rotated in the separated state;
Equipped with
the first storage area further stores a first coefficient corresponding to the first number of rotations;
the second storage area further stores a second coefficient corresponding to the second number of rotations, the second coefficient being smaller than the first coefficient;
a drum cartridge characterized in that an amount of wear of the photosensitive drum caused by rotation of the photosensitive drum is determined by adding together an accumulation of the number obtained by multiplying the first number of rotations by the first coefficient and an accumulation of the number obtained by multiplying the second number of rotations by the second coefficient smaller than the first coefficient. 5. The drum cartridge according to claim 3, wherein the first coefficient and the second coefficient are values which change based on the temperature of the photosensitive drum when the photosensitive drum is rotated. 6. The drum cartridge according to claim 3, wherein the first coefficient and the second coefficient are determined to be larger values as the total number of rotations of the photosensitive drum since the start of use of the photosensitive drum increases. The drum cartridge is
The developing roller is used together with a developing cartridge including the developing roller,
7. The drum cartridge according to claim 1, wherein the developing cartridge is mountable or detachable. 8. The drum cartridge according to claim 1, further comprising a separation mechanism for switching between the contact state and the separated state. The drum cartridge is
A plurality of the photoconductor drums are provided,
9. The drum cartridge according to claim 1, wherein the drum cartridge is a drawer that can be pulled out from a main body of an image forming apparatus. A drum cartridge,
a photosensitive drum that rotates about a first axis extending in an axial direction, the photosensitive drum being in a contact state in which an outer circumferential surface of a developing roller is in contact with an outer circumferential surface of the photosensitive drum, or in a separated state in which an outer circumferential surface of the developing roller is separated from an outer circumferential surface of the photosensitive drum;
a drum memory that stores an amount of wear of the photosensitive drum that is worn down by the rotation of the photosensitive drum, the amount being determined based on a first rotation number that is the number of times the photosensitive drum rotates in the contact state and a second rotation number that is the number of times the photosensitive drum rotates in the separated state;
Equipped with
The amount of wear of the photosensitive drum caused by the rotation of the photosensitive drum is
a number obtained by multiplying a first total number of rotations, which is the cumulative number of times the photosensitive drum has rotated in the contact state since the start of use of the photosensitive drum, by a first coefficient;
a number obtained by multiplying a second total number of rotations, which is an accumulation of the number of rotations of the photosensitive drum in the separated state since the start of use of the photosensitive drum, by a second coefficient smaller than the first coefficient;
The drum cartridge is characterized in that the value is determined by adding A drum cartridge,
a photosensitive drum that rotates about a first axis extending in an axial direction, the photosensitive drum being in a contact state in which an outer circumferential surface of a developing roller is in contact with an outer circumferential surface of the photosensitive drum, or in a separated state in which an outer circumferential surface of the developing roller is separated from an outer circumferential surface of the photosensitive drum;
a drum memory that stores an amount of wear of the photosensitive drum that is worn down by the rotation of the photosensitive drum, the amount being determined based on a first rotation number that is the number of times the photosensitive drum rotates in the contact state and a second rotation number that is the number of times the photosensitive drum rotates in the separated state;
Equipped with
The amount of wear of the photosensitive drum caused by the rotation of the photosensitive drum is
an accumulation of a number obtained by multiplying the first number of rotations by a first coefficient corresponding to the first number of rotations;
an accumulation of a number obtained by multiplying the second number of rotations by a second coefficient corresponding to the second number of rotations, the second coefficient being smaller than the first coefficient;
The drum cartridge is characterized in that the value is determined by adding: 12. The drum cartridge according to claim 10, wherein the first coefficient and the second coefficient are determined to be smaller values as the temperature of the photosensitive drum when the photosensitive drum is rotated increases. 13. The drum cartridge according to claim 10, wherein the first coefficient and the second coefficient are determined to be larger values as the total number of rotations of the photosensitive drum since the start of use of the photosensitive drum increases. The drum cartridge is
The developing roller is used together with a developing cartridge including the developing roller,
14. The drum cartridge according to claim 10, wherein the developing cartridge is mountable or detachable. 15. The drum cartridge according to claim 10 , further comprising a separation mechanism for switching between the contact state and the separated state. The drum cartridge is
A plurality of the photoconductor drums are provided,
16. The drum cartridge according to claim 10 , which is a drawer that can be pulled out from a main body of an image forming apparatus.

Images