Image forming apparatus

Abstract

To appropriately notify a user of a service life of a developing device in a configuration in which a developer carrier is driven to rotate in a developing separation state.SOLUTION: An image forming apparatus 100 has: a moving mechanism 130 that moves a developer carrier 42; a driving unit 127 that can rotate the developer carrier 42 in either case where the developer carrier 42 is arranged at a first position in contact with an image carrier 1 or at a second position separated from the image carrier 1 compared to the first position; an acquisition unit 60 that acquires information on an amount of rotation of the developer carrier 42; and a notification unit 81. The acquisition unit 60 corrects first information on the amount of rotation of the developer carrier 42 at the first position to third information by using a first correction coefficient k1, and corrects second information on the amount of rotation of the developer carrier 42 at the second position to fourth information by using a second correction coefficient k2 different from the first correction coefficient k1. The notification unit 81 performs notification on a service life of a developing device 4 on the basis of the third information and the fourth information.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a multifunction machine having a plurality of functions of these machines, which uses an electrophotographic or electrostatic recording system. [Background technology]

[0002] In an image forming apparatus using an electrophotographic method or the like, an electrostatic latent image formed on the surface of an image carrier is developed with a developer supplied by a developer carrier of a developing device to form an image. Image forming apparatuses using a developing device of a contact development method, in which a developing operation is performed while the developer carrier is in contact with the image carrier, are also known. A rotatable photosensitive drum is often used as the image carrier.

[0003] A developing device using a contact development method generally includes a rotatable developing roller as a developer carrier, a regulating blade as a regulating member, and a rotatable supply roller as a supply member. The toner as the developer is carried and transported by the supply roller, and is supplied to the surface of the developing roller at the contact portion between the supply roller and the developing roller. The toner on the developing roller is frictionally charged at the contact portion with the regulating blade and the layer thickness is regulated, and adheres to the image portion of the electrostatic latent image formed on the surface of the photosensitive drum at the contact portion with the photosensitive drum to develop the electrostatic latent image. In addition, the toner not used for development is peeled off from the surface of the developing roller at the contact portion between the developing roller and the supply roller and collected in the developing device.

[0004] Patent document 1 discloses a configuration in which the detection result of the amount of rotation of the developing roller is corrected taking into account the degree of toner deterioration corresponding to the amount of toner remaining in the developing device, and it is determined that the developing device has reached the end of its life based on the correction result (herein referred to as "life judgment"). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-161645 A Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, an image forming apparatus using a developing device of a contact development system may be configured to have a contact / separation mechanism that brings the developing roller into contact with and separates it from the photosensitive drum. The state in which the developing roller is in contact with the photosensitive drum is also called the "development contact state," and the state in which the developing roller is separated from the photosensitive drum is also called the "development separation state." Such an image forming apparatus may be configured so that the developing roller is rotationally driven in the development separation state.

[0007] However, in the conventional technology, the amount of rotation of the developing roller is accumulated in the same way regardless of whether the developing roller is in the developer contact state or the developer separation state. Therefore, for example, the end of life may be determined before the filming state of the developing roller caused by the degree of toner deterioration reaches a threshold value. As a result, it may not be possible to properly notify the user that the developing device has reached the end of its life (also referred to as "end of life notification" here).

[0008] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide an appropriate life notification for a developing device in a configuration in which the developer carrier is rotationally driven in a development separation state. [Means for solving the problem]

[0009] The above object is achieved by the image forming apparatus according to the present invention. In summary, the present invention provides a developing device including an image carrier that carries a developer image, a developer carrier that carries a developer and rotates to supply the developer to the image carrier to form a developer image on the image carrier, a moving mechanism that moves the developer carrier to a first position where the developer carrier and the image carrier are in contact with each other, and a second position that is farther away from the image carrier than the first position, a drive unit that can rotate the developer carrier when the developer carrier is located at either the first position or the second position, and an acquisition unit that acquires information regarding the amount of rotation of the developer carrier. and an alarm unit that provides an alarm regarding the life of the developing device, wherein the acquisition unit corrects first information regarding the amount of rotation of the developer carrier when the developer carrier is arranged at the first position into third information using a first correction coefficient, and corrects second information regarding the amount of rotation of the developer carrier when the developer carrier is arranged at the second position into fourth information using a second correction coefficient different from the first correction coefficient, and the alarm unit provides an alarm regarding the life of the developing device based on the third information and the fourth information. Effect of the Invention

[0010] According to the present invention, in a configuration in which the developer carrier is rotationally driven in a development separation state, it is possible to appropriately notify the end of life of the developing device. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic cross-sectional view of an image forming apparatus. [Diagram 2] FIG. 2 is a schematic cross-sectional view of an image forming unit. [Diagram 3] 11 is a schematic diagram for explaining a contact / separation mechanism. FIG. [Figure 4] FIG. 2 is a block diagram showing an outline of a control mode of the image forming apparatus. [Diagram 5] FIG. 2 is a block diagram showing functional blocks of a control unit. [Figure 6]FIG. 4 is a flowchart of a lifespan determination sequence in the first embodiment. [Figure 7] FIG. 2 is a block diagram showing functional blocks of a control unit in Comparative Examples 1 and 2. [Figure 8] FIG. 13 is a flowchart of a lifespan determination sequence in Comparative Examples 1 and 2. [Figure 9] FIG. 11 is a block diagram showing an outline of a control mode of the image forming apparatus according to the second and third embodiments. [Figure 10] FIG. 11 is a flowchart of a lifespan determination sequence in the second embodiment. [Figure 11] FIG. 11 is a flowchart of a lifespan determination sequence in the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of an image forming apparatus according to the present invention will be described in more detail with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of the components described in the embodiment may be changed as appropriate depending on the configuration and various conditions of the apparatus to which the present invention is applied. In other words, the scope of the present invention is not limited to the following embodiment.

[0013] [Example 1] <Overall configuration of image forming apparatus and image forming operation> The overall configuration and image forming operation of an image forming apparatus 100 of the first embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic cross-sectional view of the image forming apparatus 100 of the first embodiment. In the first embodiment, the image forming apparatus 100 is a tandem type laser beam printer employing an intermediate transfer method, capable of forming a full-color image using an electrophotographic method.

[0014] The image forming apparatus 100 has, as a plurality of image forming units, four image forming units (stations) SY, SM, SC, and SK that form images of each color, yellow (Y), magenta (M), cyan (C), and black (K). Elements having the same or corresponding functions or configurations for each color may be generally described by omitting the suffixes Y, M, C, and K of the reference numerals indicating that the elements are for any one of the colors. FIG. 2 is a schematic cross-sectional view showing the configuration of the image forming unit S in more detail. In the first embodiment, the image forming unit S is composed of a photosensitive drum 1, a charging roller 2, an exposure device 3, a developing device 4, a primary transfer roller 6, a drum cleaning device 5, and the like, which will be described later. In the first embodiment, the exposure device 3 is configured as one unit common to each image forming unit S, but may be provided for each image forming unit S.

[0015] The photosensitive drum 1, which is a rotatable drum-type (cylindrical) photosensitive member (electrophotographic photosensitive member) serving as an image carrier, is driven to rotate in the direction of arrow R1 (counterclockwise direction) in the figure around its rotation axis by a driving force transmitted from a driving motor 127 (FIG. 4) serving as an image carrier driving unit serving as a driving means. In the first embodiment, the photosensitive drum 1 is driven to rotate at a rotation speed such that the moving speed (circumferential speed) of its surface (outer circumferential surface) is, for example, 140 mm / sec.

[0016] The surface of the rotating photosensitive drum 1 is uniformly charged to a predetermined potential of a predetermined polarity (negative polarity in the first embodiment) by the charging roller 2, which is a roller-type charging member serving as a charging means. In the first embodiment, the charging roller 2 is a conductive roller having a conductive rubber layer provided on a metal core, and is disposed in contact with the photosensitive drum 1 with a predetermined pressure, and rotates in accordance with the rotation of the photosensitive drum 1. During image formation (charging), a predetermined charging voltage (charging bias) is applied to the charging roller 2 by a charging power source 121 (FIG. 4) serving as a charging voltage application means (charging voltage application section). In the first embodiment, a DC voltage of, for example, −1150V is applied to the charging roller 2 during image formation (charging), and the surface potential of the photosensitive drum 1 becomes approximately −500V.

[0017] The surface of the charged photosensitive drum 1 is scanned and exposed by an exposure device (exposure unit) 3 with a laser beam corresponding to an image signal (image information) of a color component corresponding to each image forming section S, and an electrostatic latent image (electrostatic image) corresponding to the image signal is formed on the photosensitive drum 1. The image signal is input to the image forming apparatus 100 in response to a request from a user (operator), for example, from an image reading device (not shown) connected to the apparatus body 110 of the image forming apparatus 100. Alternatively, the image signal is input to the image forming apparatus 100 in response to a request from a host device (external device) (not shown), such as a personal computer, communicably connected to the apparatus body 110.

[0018] The electrostatic latent image formed on the photosensitive drum 1 is developed (visualized) by supplying toner 90 as a developer by the developing device 4 as a developing means, and a toner image (toner image, developer image) is formed on the photosensitive drum 1. In the first embodiment, the developing device 4 attaches toner 90 charged with the same polarity as the charging polarity of the photosensitive drum 1 (negative polarity in the first embodiment) to a portion (image portion, exposed portion) on the surface of the photosensitive drum 1 where the absolute value of the potential has been reduced by exposure after uniform charging processing (reverse development method). In the first embodiment, the developing device 4 uses toner 90, which is a non-magnetic one-component developer with a normal charging polarity (charging polarity for developing an electrostatic latent image) of negative polarity, as the developer. The developing device 4 will be described in more detail later.

[0019] An intermediate transfer belt 7, which is an endless belt serving as an intermediate transfer body, is disposed so as to face the four photosensitive drums 1. The intermediate transfer belt 7 is stretched around a drive roller 21, a tension roller 22, and a secondary transfer opposing roller 23 serving as a plurality of tension rollers, and stretched with a predetermined tension. The intermediate transfer belt 7 rotates (circumferentially moves) in the direction of arrow R2 in the figure (clockwise direction) by the drive roller 21 being driven and rotated by a belt drive motor 129 (FIG. 4) serving as an intermediate transfer body drive unit serving as a drive means. The intermediate transfer belt 7 rotates at a rotation speed at which the moving speed (circumferential speed) of its surface (outer peripheral surface) is substantially the same as the moving speed (circumferential speed) of the surface (outer peripheral surface) of the photosensitive drum 1. Primary transfer rollers 6Y, 6M, 6C, and 6K, which are roller-type primary transfer members serving as primary transfer means, are disposed on the inner peripheral surface side of the intermediate transfer belt 7, corresponding to the photosensitive drums 1Y, 1M, 1C, and 1K, respectively. The primary transfer roller 6 is pressed against the photosensitive drum 1 via the intermediate transfer belt 7, forming a primary transfer portion (primary transfer nip portion) N1, which is a contact portion between the photosensitive drum 1 and the intermediate transfer belt 7. The toner image formed on the photosensitive drum 1 is electrostatically transferred (primary transfer) onto the rotating intermediate transfer belt 7 as a transfer target by the action of the primary transfer roller 6 at the primary transfer portion N1. During image formation (primary transfer), a predetermined primary transfer voltage (primary transfer bias), which is a DC voltage of the opposite polarity to the normal charging polarity of the toner 90, is applied to the primary transfer roller 6 by a primary transfer power source 125 (FIG. 4) as a primary transfer voltage application means (primary transfer voltage application portion). For example, during the formation of a full-color image, the toner images of the YMCK colors formed on each photosensitive drum 1 are transferred sequentially onto the intermediate transfer belt 7 so as to be superimposed on each other.

[0020] A secondary transfer roller 9, which is a roller-type secondary transfer member serving as a secondary transfer means, is disposed at a position facing the secondary transfer opposing roller 23 on the outer peripheral surface side of the intermediate transfer belt 7. The secondary transfer roller 9 is pressed against the secondary transfer opposing roller 23 via the intermediate transfer belt 7 to form a secondary transfer portion (secondary transfer nip portion) N2, which is a contact portion between the intermediate transfer belt 7 and the secondary transfer roller 9. The toner image formed on the intermediate transfer belt 7 is transferred (secondarily transferred) onto a recording material P, such as a recording paper or a plastic sheet, which is a transfer target material being sandwiched and conveyed between the intermediate transfer belt 7 and the secondary transfer roller 9, by the action of the secondary transfer roller 9 in the secondary transfer portion N2. During image formation (secondary transfer), a predetermined secondary transfer voltage (secondary transfer bias), which is a DC voltage of a polarity opposite to the normal charging polarity of the toner 90, is applied to the secondary transfer roller 9 by a secondary transfer power source 126 (FIG. 4) serving as a secondary transfer voltage application means (secondary transfer voltage application portion). The recording material P is stored in a cassette 11 serving as a recording material storage unit of the feeding unit 10. The recording material P in the cassette 11 is separated one by one and sent out of the cassette 11 by a feeding roller 12 serving as a feeding member of the feeding unit 10. The recording material P is transported to the secondary transfer unit N2 by a transport roller (registration roller) 13 serving as a transport member so as to be synchronized with the toner image on the intermediate transfer belt 7.

[0021] The recording material P onto which the toner image has been transferred is transported to a fixing device 14 as a fixing means. In the process of nipping and transporting the recording material P carrying the unfixed toner image between a pair of fixing rollers, the fixing device 14 applies pressure and heat to the toner image on the recording material P to fix (melt and adhere) it onto the recording material P. The recording material P onto which the toner image has been fixed is discharged (output) as an image formed product onto a tray 16 as a discharge unit provided outside the apparatus main body 110.

[0022] Meanwhile, the toner 90 (primary transfer residual toner) remaining on the photosensitive drum 1 after the primary transfer is removed from the photosensitive drum 1 and collected by a drum cleaning device 5 serving as an image carrier cleaning means. The drum cleaning device 5 has a cleaning blade 51 serving as a cleaning member arranged in contact with the surface of the photosensitive drum 1, and a cleaning container 52 (FIG. 2). The drum cleaning device 5 scrapes off the primary transfer residual toner from the surface of the rotating photosensitive drum 1 with the cleaning blade and stores it in the cleaning container 52. In addition, a belt cleaning device 15 serving as an intermediate transfer body cleaning means is arranged on the outer circumferential surface side of the intermediate transfer belt 7. The belt cleaning device 15 is arranged downstream of the secondary transfer portion N2 and upstream of the primary transfer portion (the most upstream primary transfer portion N1Y) in the rotation direction (the movement direction of the surface) of the intermediate transfer belt 7. Toner 90 remaining on the intermediate transfer belt 7 after the secondary transfer (secondary transfer residual toner) and adhering matter such as paper powder adhering to the intermediate transfer belt 7 during the secondary transfer are removed from the intermediate transfer belt 7 and collected by the belt cleaning device 15. However, the image forming apparatus 100 is not limited to this configuration. For example, the image forming apparatus 100 may be configured not to include a dedicated cleaning means for cleaning the photosensitive drum 1, and may be configured such that the primary transfer residual toner is collected by the developing device 4 (cleanerless system).

[0023] As shown in FIG. 2, in the first embodiment, in each image forming section S, the photosensitive drum 1, the charging roller 2 acting on the photosensitive drum 1, the developing device 4, and the drum cleaning device 5 are integrated as a process cartridge 8. The process cartridge 8 is configured to be detachable from the main body 110 of the apparatus. The main body 110 of the apparatus is a portion of the image forming apparatus 100 excluding the process cartridges 8. However, the image forming apparatus 100 is not limited to such a configuration. For example, the image forming apparatus 100 may be configured such that the developing device 4 is a cartridge (developing cartridge) that is substantially detachable from the main body 110 of the apparatus. In the first embodiment, the process cartridge 8 is configured by connecting a drum unit 50 and a developing device (developing unit) 4. The drum unit 50 is provided with a photosensitive drum 1, a charging roller 2, and a drum cleaning device 5. The photosensitive drum 1 and the charging roller 2 are rotatably supported by a cleaning container (frame) 52 constituting the drum cleaning device 5. The cleaning container 52 also supports a cleaning blade 51 .

[0024] <Developing device> Next, the developing device 4 in the first embodiment will be described.

[0025] As shown in FIG. 2, the developing device 4 has a rotatable developing roller 42 as a developer carrier (developing member), a rotatable supply roller 43 as a supply member, a regulating blade 44 as a regulating member, and a developing container (frame) 41 that contains toner 90. The developing roller 42 contacts the surface of the photosensitive drum 1 to form a developing section, and supplies the toner 90, which is charged to the normal charging polarity, to the electrostatic latent image on the photosensitive drum 1 in the developing section. The developing roller 42 and the supply roller 43 are each rotatably supported by the developing container 41. The developing roller 42 is rotated in the direction of the arrow R3 in the figure (clockwise direction) by a driving force transmitted from a driving motor 127 (FIG. 4) shared with the photosensitive drum 1. Similarly, the supply roller 43 is rotated in the direction of the arrow R4 in the figure (clockwise direction) by a driving force transmitted from the driving motor 127 (FIG. 4). In the first embodiment, when the developing roller 42 is rotated, the supply roller 43 is also rotated. That is, the developing roller 42 is rotationally driven so that the movement directions of the surfaces of the photosensitive drum 1 and the developing roller 42 are forward at the opposing portion (contact portion) with the photosensitive drum 1. The supply roller 43 is rotationally driven so that the movement directions of the surfaces of the developing roller 42 and the supply roller 43 are reverse at the opposing portion (contact portion) with the developing roller 42.

[0026] In the developing device 4, the toner 90 is supplied to the surface of the developing roller 42 by the supply roller 43. The toner 90 held (carried) on the developing roller 42 is thinned by regulating the layer thickness (thickness of the toner layer) by the regulating blade 44. Here, the regulating blade 44 has a function of regulating the layer thickness of the toner 90 on the developing roller 42 and a function of imparting a predetermined charge to the toner 90 on the developing roller 42. The thinned toner 90 is transported to a contact portion with the photosensitive drum 1 as the developing roller 42 rotates, and develops the electrostatic latent image formed on the surface of the photosensitive drum 1. The toner 90 that is not used for development and remains on the developing roller 42 is removed from the developing roller 42 at the contact portion with the supply roller 43. The toner 90 removed from the developing roller 42 is stirred and mixed with the toner 90 in the developing container 41.

[0027] The developing roller 42 is configured such that a conductive elastic rubber layer having a predetermined volume resistance is provided on the outer periphery of a metal core, and the surface of the developing roller 42 has a predetermined surface roughness. The developing roller 42 may be a single-layer roller or a roller having a multi-layer structure. For example, a single-layer roller may be one in which an elastic layer is formed on a core from a rubber material such as silicone rubber, urethane rubber, or hydrin rubber. For example, a multi-layer roller may be one in which a surface layer is formed by coating the surface of the elastic layer similar to the above with silicone resin, urethane resin, polyamide resin, or fluororesin.

[0028] 3(a) and 3(b), the image forming apparatus 100 is provided with a contact / separation mechanism 130, which is a moving mechanism for bringing the developing roller 42 into contact with and separating it from the photosensitive drum 1. In the first embodiment, the contact / separation mechanism 130 is provided for each image forming unit for each color of YMCK. FIG. 3(a) shows a state in which the developing roller 42 is disposed at a contact position, which is a first position where the developing roller 42 contacts the photosensitive drum 1, and the developing roller 42 is in contact with the photosensitive drum 1 ("development contact state"). FIG. 3(b) shows a state in which the developing roller 42 is disposed at a separation position, which is a second position where the developing roller 42 is separated from the photosensitive drum 1, and the developing roller 42 is separated from the photosensitive drum 1 ("development separation state"). In the first embodiment, the developing device (developing unit) 4 is rotatable with respect to the drum unit 50, and is biased by a pressure spring (not shown) which is a biasing member serving as a biasing means so as to rotate the developing roller 42 in a direction in which the developing roller 42 contacts the photosensitive drum 1. In the first embodiment, the contact / separation mechanism 130 includes a contact / separation cam 131 which serves as a contact / separation member, and a contact / separation motor 132 which serves as a contact / separation drive section serving as a drive means. The contact / separation mechanism 130 can separate the developing roller 42 from the photosensitive drum 1 by rotating the developing device 4 against the biasing force of the pressure spring when the contact / separation cam 131 is driven by the contact / separation motor 132 (FIG. 3(b)). In addition, the contact / separation mechanism 130 allows the contact / separation cam 130 to be driven by the contact / separation motor 132 and the developing device 4 to rotate by being biased by the above-mentioned pressure spring, thereby allowing the developing roller 42 to contact the photosensitive drum 1 (Figure 3(a)).

[0029] In the first embodiment, the developing roller 42 is stopped in a state (development separation state) in which it is separated from the photosensitive drum 1 by the contact / separation mechanism 130, for example, when the image forming apparatus 100 stops operating. In the first embodiment, the photosensitive drum 1 is rotated and driven by the drive motor 127 (FIG. 4) in response to the start of an image forming operation or the like. At the same time, the developing roller 42 is rotated and driven by the drive motor 127 (FIG. 4) shared with the photosensitive drum 1 in a state in which it is separated from the photosensitive drum 1 by the contact / separation mechanism 130. Then, at a predetermined timing, the contact / separation mechanism 130 operates, and the developing roller 42 is brought into contact with the photosensitive drum 1 at a predetermined contact width by the pressure spring, and a developing operation or the like is performed. In the first embodiment, in order to obtain an appropriate image density, the developing roller 42 is rotated and driven at a rotation speed at which the moving speed (circumferential speed) of the surface of the developing roller 42 is, for example, 125% of the moving speed (circumferential speed) of the surface of the photosensitive drum 1.

[0030] The supply roller 43 is an elastic sponge roller having a foamed layer formed of a conductive foam on the outer periphery of a metal core. The supply roller 43 is arranged so as to contact the developing roller 42 with a predetermined penetration amount. In the first embodiment, the supply roller 43 has a foamed layer formed of urethane rubber, and the urethane rubber of the foamed layer contains an ion conductive agent. In the first embodiment, the supply roller 43 is configured such that an ion conductive agent formed of a salt of a cation and an anion having a reactive functional group that reacts with an isocyanate group is chemically bonded to the urethane rubber of the foamed layer via the reactive functional group. For example, the supply roller 43 having such a configuration can be manufactured by foaming and curing a urethane composition containing an ion conductive agent.

[0031] The regulating blade 44 is made of a plate-like elastic member having conductivity and flexibility. The regulating blade 44 is a plate-like member having a substantially rectangular shape in plan view, with a predetermined length in a longitudinal direction disposed substantially parallel to the rotation axis direction of the developing roller 42 and a lateral direction substantially perpendicular to the longitudinal direction. One end of the regulating blade 44 in the lateral direction is fixed to the developing container 41 and supported by a cantilever, and the other end in the lateral direction is a free end. The regulating blade 44 abuts against the surface (outer peripheral surface) of the developing roller 42 at a surface near the free end. The regulating blade 44 is disposed so as to contact the surface of the developing roller 42 at a position downstream of the opposing portion (contact portion) between the supply roller 43 and the developing roller 42 in the moving direction (rotation direction) of the surface of the developing roller 42. In the first embodiment, a SUS material is used as the elastic member of the regulating blade 44. In the first embodiment, the regulating blade 44 is provided so that its free end in the short side direction faces the upstream side of the moving direction of the surface of the developing roller 42 (counter direction).

[0032] During image formation (development), a predetermined DC voltage is applied to the developing roller 42, the supply roller 43, and the regulating blade 44. In the first embodiment, during image formation (development), a DC voltage of −350 V is applied to the developing roller 42 as a developing voltage (development bias) by a developing power source 122 (FIG. 4) serving as a developing voltage application means (development voltage application section). During image formation (development), a DC voltage of −450 V is applied to the supply roller 43 as a supply voltage (supply bias) by a supply power source 123 (FIG. 4) serving as a supply voltage application means (supply voltage application section). During image formation (development), a DC voltage of −450 V is applied to the regulating blade 44 as a regulating voltage (regulating bias) by a regulating power source 124 (FIG. 4) serving as a regulating voltage application means (regulating voltage application section). In the first embodiment, since the normal charging polarity of the toner 90 is negative, the potential difference between the supply roller 43 and the development roller 42 is set to a polarity that urges (moves) the toner 90 from the supply roller 43 side to the development roller 42 side. In other words, a potential difference is formed between the supply roller 43 and the development roller 42, in which the potential of the supply roller 43 is larger in the same polarity as the normal charging polarity of the toner 90 than the potential of the development roller 42. This makes it possible to stabilize the supply of the toner 90 from the supply roller 43 to the development roller 42. In addition, the potential difference between the regulating blade 44 and the development roller 42 is set to a polarity that urges the toner 90 from the regulating blade 44 side to the development roller 42 side. In other words, a potential difference is formed between the regulating blade 44 and the development roller 42, in which the potential of the regulating blade 44 is larger in the same polarity as the normal charging polarity of the toner 90 than the potential of the development roller 42. This makes it possible to stabilize the intake of the toner 90 into the contact portion between the regulating blade 44 and the development roller 42, and stabilize the application of the electric charge to the toner 90 by the regulating blade 44.

[0033] In Example 1, a negatively charged non-magnetic toner manufactured by a suspension polymerization method was used as the toner 90. However, the toner 90 is not limited thereto, and may be a toner manufactured by other polymerization methods such as a pulverization method or an emulsion polymerization method. The volume average particle diameter of the toner 90 is preferably 5.0 to 8.0 μm. Here, the volume average particle diameter of the toner 90 was measured by a precision particle size distribution measuring device, Multisizer 3, manufactured by Beckman Coulter, Inc. In Example 1, the volume average particle diameter of the toner 90 was about 7.0 μm.

[0034] In Example 1, all of the four color toners 90Y, 90M, 90C, and 90K are toner particles that contain toner base particles containing a release agent and an organosilicon polymer on the surface of the toner base particles. 1 / 2 )3, in which R represents an alkyl group or a phenyl group having 1 to 6 carbon atoms, and the organosilicon polymer forms a convex portion on the surface of the toner base particle. This creates a spacer effect between the surface of the toner base particle and a member such as the developing roller 42, reducing the adhesive force. The convex portion is characterized by being in surface contact with the surface of the toner base particle, and the surface contact is expected to have a significant effect of suppressing the movement, detachment, and embedment of the convex portion. Therefore, even in a configuration in which the developing roller 42 is driven in a state separated from the photosensitive drum 1, the developing roller 42 can be used for a long period of time. However, although toner particles containing an organosilicon polymer on the surface of the toner base particle are used in Example 1, the present invention is not limited to this, and toner particles not containing an organosilicon polymer on the surface of the toner base particle may be used, for example.

[0035] Toner 90 may contain additives (also referred to as "external additives" herein) such as a fluidizing agent and a cleaning aid in order to improve fluidity, chargeability, cleaning properties, etc. Examples of external additives include inorganic oxide fine particles such as silica fine particles, alumina fine particles, and titanium oxide fine particles, inorganic stearic acid compound fine particles such as aluminum stearate fine particles and zinc stearate fine particles, and inorganic titanic acid compound fine particles such as strontium titanate and zinc titanate. These may be used alone or in combination of two or more. These inorganic fine particles are preferably gloss-treated with a silane coupling agent, a titanium coupling agent, a higher fatty acid, silicone oil, etc., in order to improve heat-resistant storage properties and environmental stability. The BET specific surface area of ​​the external additive is 10 m 2 / g or more 450m 2 The BET specific surface area can be determined by a low-temperature gas adsorption method using a dynamic constant pressure method in accordance with the BET method (preferably the BET multipoint method). For example, a specific surface area measuring device (product name: Gemini 2375 Ver. 5.0, manufactured by Shimadzu Corporation) is used to adsorb nitrogen gas onto the surface of a sample, and the BET multipoint method is used to measure the BET specific surface area (m 2 / g) can be calculated. The total amount of these various external additives is 0.05 parts by mass or more and 5 parts by mass or less, preferably 0.1 parts by mass or more and 3 parts by mass or less, relative to 100 parts by mass of the toner. Various external additives may be used in combination.

[0036] Here, in the first embodiment, the image forming apparatus 100 can perform a printing operation of transferring a toner image to a recording material P in a "full color mode" as a first image forming mode and a "monochrome mode" as a second image forming mode. The "full color mode" is an image forming mode in which an image forming operation is performed in all of the image forming units for each color of YMCK. The "monochrome mode" is an image forming mode in which an image forming operation is performed only in the image forming unit for K color among the image forming units for each color of YMCK. In the first embodiment, when performing image formation in the monochrome mode, the developing roller 42 is rotationally driven in the developing separation state in the image forming units for each color of YMC. That is, in the first embodiment, as described above, the developing roller 42 is rotationally driven by the driving motor 127 (FIG. 4) common to the photosensitive drum 1, and the developing roller 42 rotates simultaneously when the photosensitive drum 1 rotates. In the first embodiment, even in the monochrome mode, the photosensitive drums 1 for each color of YMC are rotationally driven to avoid friction with the intermediate transfer belt 7. Also, to simplify the device configuration, a clutch is not provided in the drive transmission path to the developing roller 42. Therefore, in the mono mode, when the photosensitive drum 1 and the developing roller 42 are brought into contact with each other and rotated for image formation in the image forming unit for K color, the developing roller 42 rotates even if the photosensitive drum 1 and the developing roller 42 are separated from each other in the image forming units for Y, M, and C colors.

[0037] <Control mode> Next, a description will be given of a control mode in the image forming apparatus 100 of the embodiment 1. Fig. 4 is a block diagram showing an outline of a control mode in the image forming apparatus 100 of the embodiment 1. Fig. 5 is a block diagram showing functional blocks of the control unit 30 of the embodiment 1.

[0038] As shown in Fig. 4, the device main body 110 is provided with a control unit 30 as a control means. The control unit 30 is configured to include a CPU 31 as a calculation processing means which is a central element for performing calculation processing, a storage unit 32 such as a ROM, RAM, or non-volatile memory as a storage means, and an input / output unit (not shown). The ROM stores a control program, a data table obtained in advance, and the like. The RAM stores information input to the control unit 30, detected information, calculation results, and the like. The input / output unit inputs and outputs signals between the control unit 30 and devices connected thereto.

[0039] Each part of the image forming apparatus 100 is connected to the control unit 30. The control unit 30 communicates bidirectionally with each part of the image forming apparatus 100 to control the operation of each part. For example, various power sources (power supply devices, high-voltage power supply circuits) such as a charging power source 121, a developing power source 122, a supply power source 123, a regulating power source 124, a primary transfer power source 125, and a secondary transfer power source 126 are connected to the control unit 30. Also, for example, various motors (drive units, drive sources) such as a drive motor 127, a belt drive motor 129, and a contact / separation motor 132 are connected to the control unit 30. The drive motor 127 may be common to the image forming units for each color of YMCK, or may be provided independently for at least one (or all) of the image forming units for each color of YMCK. Also, for example, an image processing unit 17, an exposure device 3, an operation panel 20, and the like are connected to the control unit 30. The control unit 30 controls each unit of the image forming apparatus 100 to perform an image forming operation based on signals (start signal, image signal) input from an external device (not shown) such as a personal computer. The image processing unit (video controller) 17 generates an image signal used for image formation in the image forming apparatus 100 based on the signal input from the external device. The operation panel 20 is configured to include a display unit for displaying information to a user (operator) under the control of the control unit 30, an input unit for inputting information to the control unit 30 according to the user's operation, and the like.

[0040] In the first embodiment, the process cartridge 8 is provided with a memory 80 (FIGS. 2 and 4) which is a non-volatile storage means. The memory 80 stores usage information and life information of the developing device 4 (developing roller 42), usage information and life information of the toner 90, and the like. This makes it possible to calculate the usage status and replacement time (life) of the developing device 4 (developing roller 42) even when the power of the main body 110 of the apparatus is turned on / off or when the process cartridge 8 is replaced. In the first embodiment, the memory 80 is provided in the cleaning container 52. However, this is not limited thereto, and the memory 80 may be provided in the developing device 4, for example. The control unit 30 can read and write information from and to the memory 80 of the process cartridge 8 mounted in the main body 110 of the apparatus.

[0041] 5, the image forming apparatus 100 includes a traveling distance calculation device 60 as a rotation amount acquisition unit, a developer amount detection device 70 as a developer amount acquisition unit, and a life determination unit 81 as a notification unit. In the first embodiment, the traveling distance calculation device 60, the developer amount detection device 70, and the life determination unit 81 are realized by the CPU 31 executing a program stored in the storage unit (ROM) 32.

[0042] The travel distance calculation device 60 has a contact travel distance measurement unit 61 that counts (measures) a contact travel distance W1, which is a travel distance as the amount of rotation of the developing roller 42 in the development contact state. The travel distance calculation unit 60 also has a separation travel distance measurement unit 62 that counts (measures) a separation travel distance W2, which is a travel distance as the amount of rotation of the developing roller 42 in the development separation state. The travel distance calculation device 60 also has a contact travel distance calculation unit 63 that corrects the contact travel distance W1. The travel distance calculation device 60 also has a separation travel distance calculation unit 64 that corrects the separation travel distance W2. The travel distance calculation device 60 also has a travel distance calculation unit 65 that calculates the travel distance as the amount of rotation of the developing roller 42 from the corrected contact travel distance and the corrected separation travel distance.

[0043] However, the information regarding the amount of rotation of the developing roller 42 is not limited to the distance traveled by the developing roller 42, but may be the number of rotations of the developing roller 42, the rotation time (driving time), etc., and any index value that correlates with the amount of rotation (driving amount) of the developing roller 42 can be used.

[0044] The developer amount detection device 70 detects the remaining amount of toner 90 (toner remaining amount) in the development device 4 as developer amount information related to the amount of toner 90 (toner amount) in the development device 4. In the first embodiment, a video count method is adopted as a method for detecting the toner amount. The developer amount detection device 70 has a video count measurement unit 71 that measures pixel information (number of pixel signals: video count value) of an output image (image portion of an electrostatic latent image) formed on a recording material P by an image forming operation. The developer amount detection device 70 also has a developer remaining amount calculation unit 72 that calculates the remaining amount of toner in the development device 4 based on the measured video count value.

[0045] However, the toner amount detection method is not limited to the developer amount detection device 70 of the video count method. For example, known detection methods of remaining toner amount such as electrostatic capacitance method, light transmission method (optical detection method), weight detection method, and developer surface detection method may be used. The electrostatic capacitance method is a method of detecting the amount of toner in the developing device 4 based on the change in the detected electrostatic capacitance using an electrode whose electrostatic capacitance changes according to the change in the state of the toner in the developing device 4 (for example, by attaching a conductive member to the inner wall of the container). The light transmission method is a method of detecting the amount of toner based on the change in the light receiving state of the light receiving unit using a light source that irradiates light into the inside of the developing device 4 and a light receiving unit that receives the light that has passed through the developing device 4. The weight detection method is a method of detecting the amount of toner in the developing device 4 based on the weight of the developing device 4 that contains toner. The developer surface detection method is a method of detecting the amount of toner in the developing device 4 based on the position (height) of the developer surface of the toner in the developing device 4. The toner amount detection methods such as the video count method, the capacitance method, the light transmission method, the weight detection method, the toner surface detection method, etc. may be used alone or in combination. Specifically, for example, when the remaining toner amount acquired by the video count method becomes equal to or less than a predetermined remaining toner amount, another method such as the capacitance method or the light transmission method may be used.

[0046] The life determination unit 81 determines the life of the developing device 4 (determines that the developing device 4 has reached the end of its life) based on the travel distance of the developing roller 42 calculated by the travel distance calculation device 60. Then, the life determination unit 81 notifies the user that the developing device 4 has reached the end of its life by displaying the same on the operation panel 20. In the first embodiment, the life determination unit 81 also notifies the user when the remaining amount of toner reaches a predetermined remaining amount of toner (when the remaining amount of toner is almost empty in the first embodiment) based on the remaining amount of toner detected by the developer amount detection device 70 by displaying the same on the operation panel 20. This makes it possible to more appropriately notify the user of the life (time to replace) of the developing device 4.

[0047] <Calculating the Travel Distance of the Developing Roller> Next, the calculation of the travel distance of the developing roller 42 in the first embodiment will be described.

[0048] In the first embodiment, the contact travel distance W1 and the separation travel distance W2 are measured, and the contact travel distance W1 and the separation travel distance W2 are corrected using the first and second load correction coefficients k1 and k2, respectively. Then, the travel distance of the developing roller 42 is calculated based on the corrected values.

[0049] The contact travel distance measuring unit 61, as a contact travel distance acquiring unit (first information acquiring unit), measures a contact travel distance (first information) W1 based on the driving time Td1 of the developing device 4 in the development contact state, the process speed Ps of the image forming apparatus 100, and the ratio Sr of the surface movement speed (circumferential speed) of the developing roller 42 and the photosensitive drum 1 (herein also referred to as the "development peripheral speed ratio"). Here, the contact travel distance W1 is a distance (surface movement distance) that indicates how far a certain point on the surface of the developing roller 42 has advanced (moved) by the rotation of the developing roller 42 in the development contact state. Moreover, the process speed Ps of the image forming apparatus 100 is the rotation speed (circumferential speed) of the photosensitive drum 1. Moreover, the development peripheral speed ratio Sr is the ratio of the peripheral speed of the developing roller 42 to the peripheral speed of the photosensitive drum 1 (=peripheral speed of the developing roller 42 / peripheral speed of the photosensitive drum 1). Specifically, the contact travel distance W1 is calculated by the following formula (1). W1 = Td1 × Ps × Sr (1)

[0050] Similarly, the separation travel distance measuring unit 62, as a separation travel distance acquiring unit (second information acquiring unit), measures a separation travel distance (second information) W2 based on the drive time Td2 of the developing device 4 in the development separation state, the process speed Ps of the image forming apparatus 100, and the development peripheral speed ratio Sr. Here, the separation travel distance W2 is a distance (surface travel distance) that indicates how far a certain point on the surface of the developing roller 42 has advanced (moved) due to the rotation of the developing roller 42 in the development separation state. Specifically, the separation travel distance W2 is calculated by the following formula (2). W2 = Td2 × Ps × Sr (2)

[0051] Next, when the contact mileage measurement unit 61 measures the contact mileage W1, the contact mileage calculation unit 63 reads out the first load correction coefficient k1 stored in the memory 80. Then, the contact mileage calculation unit 63, as the first correction distance acquisition unit (third information acquisition unit), multiplies the contact mileage W1 by the first load correction coefficient k1 to calculate the corrected contact mileage (third information) H1. Specifically, the corrected contact mileage H1 is calculated by the following calculation formula (3). H1 = k1 × W1 (3)

[0052] Similarly, when the separation travel distance W2 is measured by the separation travel distance measuring unit 62, the separation travel distance calculating unit 64 reads out the second load correction coefficient k2 stored in the memory 80. Then, the separation travel distance calculating unit 64, as a second correction distance acquiring unit (fourth information acquiring unit), multiplies the separation travel distance W2 by the second load correction coefficient k2 to calculate a corrected separation travel distance (fourth information) H2. Specifically, the corrected separation travel distance H2 is calculated by the following calculation formula (4). H2 = k2 × W2 (4)

[0053] Next, the travel distance calculation unit 65 adds up the corrected contact travel distance H1 and the corrected separation travel distance H2 to obtain a total travel distance (total rotation amount) H. Specifically, the total travel distance H is calculated by the following formula (5). H = H1 + H2 (5)

[0054] Furthermore, the travel distance calculation unit 65, as a total correction distance acquisition unit (fifth information acquisition unit), adds (accumulates) the predetermined total travel distance Hu to the total cumulative travel distance Hr from the start of use (when new) of the developing device 4 (process cartridge 8) stored in the memory 80 each time the obtained total travel distance H increases by a predetermined distance Hu, and calculates a total cumulative total travel distance (fifth information) Ht, which is a total correction distance (total rotation amount). Specifically, the total cumulative total travel distance Ht is calculated by the following calculation formula (6). Ht = Hr + Hu (6)

[0055] In the first embodiment, the above-mentioned predetermined total travel distance Hu is set to about two sheets of A4 paper (about 300 mm). However, the predetermined total travel distance Hu is not limited to this, and can be appropriately set according to the device configuration and the desired accuracy of the life judgment. For example, the total travel distance H may be directly integrated instead of the predetermined total travel distance Hu.

[0056] Next, the life determination unit 81 calculates the developing roller remaining life GJ based on the travel distance threshold Wth and the total accumulated combined travel distance Ht stored in the memory 80. Specifically, the developing roller remaining life GJ is calculated by the following calculation formula (7). GJ[%]=(1-Ht / Wth)×100 ···(7)

[0057] Then, the lifespan determination unit 81 writes (updates) the obtained total accumulated combined mileage Ht in the memory 80 as a new accumulated combined mileage Hr.

[0058] Here, when the developing roller remaining life GJ=100%, it indicates that the developing device 4 (process cartridge 8) is brand new. Also, when the developing roller remaining life GJ≦0%, that is, when the total accumulated combined running distance Ht exceeds the running distance threshold Wth, it indicates that the developing device 4 (process cartridge 8) has reached the end of its life and it is time to replace the developing device 4 (process cartridge 8).

[0059] When the remaining life of the developing roller GJ becomes ≦0%, the life judgment unit 81 notifies the user that the developing device 4 has reached the end of its life by displaying on the operation panel 20. The content of this display may be a message simply informing the user that the developing device 4 (developing roller 42) has reached the end of its life, a message instructing the user to replace the developing device 4 (process cartridge 8), or both of these.

[0060] As described above, in the first embodiment, the contact travel distance W1 and the separation travel distance W2 are corrected using the first and second load correction coefficients k1 and k2. This allows the travel distance of the developing roller 42 to be counted while taking into account the influence of the friction of the toner 90 and the influence of filming of the developing roller 42 in each of the development contact state and development separation state. Here, "filming" refers to a phenomenon in which the toner and external additives added to the toner adhere to and accumulate on the surface of the developing roller 42. When filming of the developing roller 42 progresses, the electrical resistance value of the developing roller 42 increases and the surface roughness of the developing roller 42 decreases. As a result, it becomes impossible to provide an appropriate charge to the toner or to secure the amount of toner required to obtain a desired image density, which may cause problems such as adhesion of the toner to non-image areas (so-called fogging) and a decrease in image density.

[0061] Specifically, in the developer separation state, the toner 90 is less affected by the friction than in the developer contact state, and the filming of the developing roller 42 progresses more slowly. In consideration of this, the load correction coefficient is set so that the progress of the running distance of the developing roller 42 in the developer separation state is slower than the progress of the running distance in the developer contact state (k1>k2). In the first embodiment, the first load correction coefficient (first correction coefficient) k1 is set to 1.0, and the second load correction coefficient (second correction coefficient) k2 is set to 0.08. That is, the absolute value of the first correction coefficient is greater than the absolute value of the second correction coefficient. In the first embodiment, the information on the first and second load correction coefficients k1 and k2 is stored in the memory 80 provided in the process cartridge 8. This is related to the characteristics of the toner 90 used in the first embodiment. In particular, in the first embodiment, toner particles containing an organosilicon polymer on the surface of the toner base particle are used, and the convex parts formed on the surface of the toner base particle have high durability against the load caused by repeated friction. Therefore, when the friction load on the toner 90 is small, the progress of filming on the developing roller 42 is considered to be small. Therefore, k1 and k2 are set to be significantly different. For the toner used this time, k2 is set to be less than 30% of k1. Furthermore, less than 10% is preferable. In addition, in the first embodiment, the toner 90 of each color has almost the same influence on the filming on the developing roller 42, so the first load correction coefficient k1 and the second load correction coefficient k2 are set to the same set values ​​for the developing devices 4Y, 4M, 4C, and 4K for each color of YMCK. However, this is not limited to this. The progress of filming on the developing roller 42 varies depending on, for example, the physical properties and shape of the toner 90, the type, shape, or amount of additives, the physical properties and surface shape of the developing roller 42, and the physical properties, surface shape, or contact conditions of the member that contacts the developing roller 42. Therefore, in accordance with these conditions, at least one of the first load correction coefficient k1 and the second load correction coefficient k2 may be made different for at least one of the developing devices 4Y, 4M, 4C, and 4K for each of the YMCK colors from those for the other colors. For example, at least one of the first load correction coefficient k1 and the second load correction coefficient k2 may be set individually for each of the developing devices 4Y, 4M, 4C, and 4K for each of the YMCK colors.

[0062] <Detecting remaining toner> Next, the developer amount detection device 70 of the video count type in the first embodiment will be described.

[0063] A video count measurement unit 71 of the developer amount detection device 70 measures pixel information (video count value) of an output image. In the first embodiment, one sheet of the output recording material P is defined as one video count value VCn (amount of toner 90 used).

[0064] The developer remaining amount calculation unit 72 of the developer amount detection device 70 calculates a total video count value VCt by adding the video count value VCn measured by the video count measurement unit 71 to the accumulated video count value VCr from the start of use of the developing device 4 (process cartridge 8) stored in the memory 80. Specifically, the total video count value VCt is calculated by the following calculation formula (8). VCt = Vcr + VCn (8)

[0065] Next, the developer remaining amount calculation unit 72 calculates the toner remaining amount TJ in the developing device 4 based on the video count threshold value VCth and the total video count value VCt stored in the memory 80. Specifically, the toner remaining amount TJ in the developing device 4 is calculated by the following calculation formula (9). TJ[%]=(1-VCt / VCth)×100 (9)

[0066] Then, the developer remaining amount calculation unit 72 writes (updates) the obtained total video count value VCt in the memory 80 as a new accumulated video count value VCr.

[0067] Here, when the toner remaining amount TJ=100%, the toner 90 in the developing device 4 is full, and the developing device 4 (process cartridge 8) is new. When the toner remaining amount TJ≦0%, that is, when the total video count value VCt exceeds the video count threshold value VCth, the toner 90 available for image formation in the developing device 4 is almost depleted, and it is time to replace the developing device 4 (process cartridge 8).

[0068] When the remaining toner amount TJ becomes ≦0%, the life judgment unit 81 notifies the user by displaying on the operation panel 20 that there is no toner left in the developing device 4. The content of this display may be a message simply informing the user that there is no toner left in the developing device 4, a message instructing the user to replace the developing device 4 (process cartridge 8), or both of these.

[0069] The remaining toner amount may be evaluated using an index called toner consumption amount. In this case, the toner consumption amount is 0% when the product is new, and the toner consumption amount is 100% when the toner amount in the developing device 4 decreases to a predetermined threshold value.

[0070] <Developing device life determination sequence> Next, a lifespan determination sequence for the developing device 4 in the first embodiment will be described. Fig. 6 is a flow chart of the lifespan determination sequence for the developing device 4 in the first embodiment. The control unit 30 performs each process shown in Fig. 6 based on information in the memory 80 provided in the process cartridge 8 to determine the lifespan of the developing device 4, and can notify the user of the result. The lifespan determination (lifespan notification) of the developing device 4 by the lifespan determination sequence shown in Fig. 6 is performed for each of the image forming units for each color of YMCK.

[0071] First, when a print signal (start signal, image signal) is sent to the image forming apparatus 100 (S101), the control unit 30 drives the developing device 4 to start the image forming operation (S102).

[0072] Next, the control unit 30, in the travel distance calculation unit 65, adds (accumulates) the distance Hu to the accumulated combined travel distance Hr stored in the memory 80 for each predetermined total travel distance Hu to calculate a total accumulated combined travel distance Ht (S103). Then, the control unit 30 calculates the remaining life GJ of the developing roller (S104) and writes the total accumulated combined travel distance Ht in the memory 80 as a new accumulated combined travel distance Hr (S105).

[0073] Next, the control unit 30 judges whether the developing roller remaining life GJ is 0% or less (whether it is less than a predetermined remaining life threshold value or not) (S106). If the control unit 30 judges that the developing roller remaining life GJ is 0% or less, it notifies the user by displaying on the operation panel 20 provided in the apparatus main body 110 that the developing device 4 has reached the end of its life (S107). On the other hand, if the control unit 30 judges that the developing roller remaining life GJ is not 0% or less (greater than 0%), the process proceeds to S108.

[0074] Next, the control unit 30 receives image information from the developer amount detection device 70 (S108). Then, the control unit 30 measures a video count value VCn in the video count measurement unit 71, and calculates a total video count value VCt in the developer remaining amount calculation unit 72 (S109). Thereafter, the control unit 30 calculates the remaining toner amount TJ (S110), and writes the total video count value VCt in the memory 80 as a new accumulated video count value VCr (S111).

[0075] Next, the control unit 30 judges whether the remaining toner amount TJ is 0% or less (whether it is less than a predetermined toner remaining amount threshold) (S112). If the control unit 30 judges that the remaining toner amount TJ is 0% or less, it notifies the user by displaying on the operation panel 20 provided in the apparatus main body 110 that the toner 90 in the developing device 4 is almost depleted and it is time to replace the developing device 4 (S107). On the other hand, if the control unit 30 judges that the remaining toner amount TJ is not 0% or less (greater than 0%), it prepares for the next image formation. Here, the notification that the developing device 4 (developing roller 42) has reached the end of its life and it is time to replace the developing device 4, or the notification that the toner 90 in the developing device 4 is almost depleted and it is time to replace the developing device 4, as described above, is also simply referred to as a "life notification."

[0076] In the first embodiment, the processes of S102 to S106 are followed by the processes of S108 to S112, but the process may be reversed (the processes of S102 to S106 are executed after the processes of S108 to S112). Also, the process may be executed in parallel with the processes of S102 to S106 and S108 to S112.

[0077] The timing for obtaining the remaining toner amount may be, for example, every predetermined total travel distance Hu, which is the timing for detecting the travel distance of the developing roller 42, that is, the time interval during which the developing roller 42 travels the predetermined total travel distance Hu. Alternatively, the timing for obtaining the remaining toner amount may be multiple times within the time during which the developing roller 42 travels the predetermined total travel distance Hu.

[0078] As described above, in the first embodiment, the travel distance of the developing roller 42 is acquired taking into consideration, for example, the influence of friction on the toner 90 and the influence of filming on the developing roller 42 in each of the developer contact state and the developer separated state. Then, based on this travel distance of the developing roller 42, the life of the developing device 4 is judged and notified to the user. As a result, even if the developing devices 4Y, 4M, and 4C for the respective colors of YMC are often driven in the developer separated state in, for example, a mono mode, it is possible to appropriately judge the life in accordance with the filming state of the developing roller 42 of each developing device 4.

[0079] Furthermore, in the first embodiment, based on the detection result of the developer amount detection device 70, it is also notified that the toner 90 in the developing device 4 is almost depleted. In other words, even if the amount of rotation of the developing roller 42 does not exceed a predetermined threshold, if the amount of remaining toner in the developing device 4 falls to or below a predetermined threshold, it is determined that the developing device 4 has reached the end of its life. This makes it possible to notify not only the life of the developing device 4 due to filming of the developing roller 42, but also the life of the developing device 4 due to the amount of remaining toner, making it possible to more appropriately notify the user of the time to replace the developing device 4 (process cartridge 8).

[0080] In the first embodiment, only the travel distance threshold Wth is used as the threshold value of the travel distance of the developing roller 42, but the present invention is not limited to this. For example, a life notice threshold WL may be set before the travel distance threshold Wth is reached. That is, when the total accumulated combined travel distance Ht reaches or exceeds the life notice threshold WL, control may be performed so as to notify the user of the end of life notice of the developing device 4. When the life notice threshold WL is set to be, for example, 90% of the travel distance threshold Wth, it is possible to notify the user of the fact that the life of the developing device 4 is nearing the end of its life when the remaining life GJ of the developing roller reaches 10%. Therefore, the user can prepare in advance for replacement of the developing device 4 (process cartridge 8). The same applies to the remaining amount of toner.

[0081] In the first embodiment, the life of the developing device 4 is notified when the developing roller remaining life GJ reaches 0%. However, this is not limited to this, and for example, the developing roller remaining life GJ can be displayed on the operation panel every time the total cumulative combined travel distance Ht is updated. In addition to automatically notifying the developing roller remaining life GJ under the control of the control unit 30 in this way, the developing roller remaining life GJ may be notified at any timing in response to the user's operation on the operation panel 20. This makes it possible to inform the user how much longer the developing device 4 (process cartridge 8) can be used, thereby providing an image forming apparatus 100 with better usability. The same applies to the remaining amount of toner.

[0082] Furthermore, the determination of the life of the developing device 4 by the various calculations described above may be calculated and controlled, for example, during operation of the image forming apparatus 100, or may be controlled using a table previously stored in the memory unit (ROM) 32.

[0083] <Comparative Example 1> Next, Comparative Example 1 will be described. The basic configuration and operation of the image forming apparatus 100 of Comparative Example 1 are the same as those of Example 1. Therefore, in the image forming apparatus of Comparative Example 1, elements having the same or corresponding functions or configurations as those of the image forming apparatus 100 of Example 1 are given the same reference numerals as those of Example 1, and detailed explanations are omitted. The same applies to Comparative Example 2 described later.

[0084] In Comparative Example 1, the travel distance of the developing roller 42 is counted without distinguishing between the developer contact state and the developer separated state, and the travel distance of the developing roller 42 is not corrected. Fig. 7 is a block diagram showing functional blocks of the control unit 30 in Comparative Example 1. In Comparative Example 1, the travel distance calculation device 60 has a travel distance measurement unit 66 that counts the travel distance W of the developing roller 42 regardless of whether it is in the developer contact state or the developer separated state, and a travel distance calculation unit 65.

[0085] (Calculation of the travel distance of the developing roller) In Comparative Example 1, the travel distance measuring unit 66 measures the travel distance W based on the drive time Td of the developing device 4, the process speed Ps of the image forming apparatus 100, and the development peripheral speed ratio Sr. Here, in Comparative Example 1, the travel distance W is a distance (surface travel distance) that indicates how far a certain point on the surface of the developing roller 42 has advanced (moved) due to the rotation of the developing roller 42, regardless of whether the developing roller 42 is in the development contact state or the development separation state. Specifically, the travel distance W is calculated by the following formula (10). W = Td × Ps × Sr (10)

[0086] Next, each time the traveling distance W obtained by the traveling distance measuring unit 66 increases by a predetermined distance Wu, the traveling distance calculating unit 65 adds (integrates) the predetermined traveling distance Wu to the accumulated traveling distance Wr from the start of use of the developing device 4 (process cartridge 8) stored in the memory 80, to calculate a total accumulated traveling distance Wt, which is the total distance. Specifically, the total accumulated traveling distance Wt is calculated by the following calculation formula (11). Wt = Wr + Wu (11)

[0087] In Comparative Example 1, the predetermined travel distance Wu was set to approximately two sheets of A4 paper (approximately 300 mm).

[0088] Next, the life determination unit 81 calculates the developing roller remaining life GJ based on the travel distance threshold Wth and the total accumulated travel distance Wt stored in the memory 80. Specifically, the developing roller remaining life GJ is calculated by the following formula (12). GJ[%]=(1-Wt / Wth)×100 ···(12)

[0089] Then, the lifespan determination unit 81 writes the total accumulated traveling distance Wt into the memory 80 as a new accumulated traveling distance Wr.

[0090] Here, when the developing roller remaining life GJ=100%, it indicates that the developing device 4 (process cartridge 8) is brand new. Also, when the developing roller remaining life GJ≦0%, that is, when the total accumulated travel distance Wt exceeds the travel distance threshold Wth, it indicates that the developing device 4 (process cartridge 8) has reached the end of its life and it is time to replace the developing device 4 (process cartridge 8).

[0091] (Developing device life determination sequence) FIG. 8 is a flowchart of a sequence for determining the end of life of the developing device 4 in Comparative Example 1. In FIG.

[0092] First, when a print signal (start signal, image signal) is sent to the image forming apparatus 100 (S201), the control unit 30 drives the developing device 4 to start the image forming operation (S202).

[0093] Next, the control unit 30 adds (accumulates) the distance Wu to the accumulated traveling distance Wr stored in the memory 80 for each predetermined traveling distance Wu in the traveling distance calculation unit 65 to calculate the total accumulated traveling distance Wt (S203). Then, the control unit 30 calculates the remaining life GJ of the developing roller (S204) and writes the total accumulated traveling distance Wt as a new accumulated traveling distance Wr in the memory 80 (S205).

[0094] Next, the control unit 30 judges whether the developing roller remaining life GJ is 0% or less (whether it is less than a predetermined remaining life threshold value or not) (S206). If the control unit 30 judges that the developing roller remaining life GJ is 0% or less, it notifies the user that the developing device 4 has reached the end of its life by displaying this on the operation panel 20 provided in the apparatus main body 110 (S207). On the other hand, if the control unit 30 judges that the developing roller remaining life GJ is not 0% or less (greater than 0%), the process proceeds to S208.

[0095] The processing in steps S208 to S212 is the same as the processing in steps S108 to S112 in FIG. 6 in the first embodiment, and therefore a description thereof will be omitted.

[0096] <Comparative Example 2> Next, a description will be given of Comparative Example 2. In Comparative Example 2, only the contact travel distance, which is the travel distance of the developing roller 42 in the development contact state, is counted, and the separation travel distance, which is the travel distance of the developing roller 42 in the development separation state, is not counted. That is, in Comparative Example 2, the contact travel distance is used as the travel distance W.

[0097] (Calculation of the travel distance of the developing roller) The functional blocks of the control unit 30 in Comparative Example 2 are similar to those in Comparative Example 1 shown in Fig. 7. In Comparative Example 2, the travel distance measurement unit 66 measures the travel distance W based on the drive time Td1 of the developing device 4 in the development contact state, the process speed Ps of the image forming apparatus 100, and the development peripheral speed ratio Sr. Here, in Comparative Example 2, the travel distance W is a distance (surface travel distance) that indicates how far a certain point on the surface of the developing roller 42 has advanced (moved) due to the rotation of the developing roller 42 in the development contact state. Specifically, the travel distance W is calculated by the following formula (13). W = Td1 × Ps × Sr (13)

[0098] The subsequent processing is the same as in Comparative Example 1, and therefore a description thereof will be omitted.

[0099] <Effectiveness verification> (Evaluation method) To confirm the effect of Example 1, a life evaluation was performed from the start of use of the developing device 4 (process cartridge 8) (developing roller remaining life GJ is 100%) until the developing roller remaining life GJ reached 0%.

[0100] Specifically, horizontal line images (lines extending in a direction approximately perpendicular to the conveying direction of the recording paper) with an image ratio of 1 to 2% were intermittently printed on A4-sized recording paper. Here, intermittent printing refers to a printing method in which the operation of the developing device 4 (image forming device 100) is temporarily stopped after a predetermined number of sheets are printed, and then the printing operation is performed again. In this evaluation, the operation of the developing device 4 (image forming device 100) is temporarily stopped after two sheets are printed in succession, and then the printing operation is performed again. The evaluation was performed under the following evaluation conditions in an environment with a temperature of 23°C and a relative humidity of 50%. Mileage threshold Wth: Equivalent to 3,000 sheets of A4 size paper printed intermittently Evaluation mode (1): Image formation in full color mode only Evaluation mode (2): Mono and full color modes are used in combination at an average ratio of 5:5 to form an image.

[0101] In each evaluation mode, the occurrence of image defects when the remaining life GJ of the developing roller reached 0% was evaluated. In this evaluation, the image defects were visually judged and evaluated in terms of the decrease in image density (especially the low density in the latter half of an all-black image) due to filming of the developing roller 42 according to the following criteria. ○: No thinning of the second half of the print, or slight thinning but no practical problem ×: The density of the second half is significantly low, and there is a problem in practical use.

[0102] Furthermore, in this evaluation, the number of sheets printed before the remaining life GJ of the developing roller reaches 0% (here, also referred to as the "printable number") was also compared. Specifically, for the process cartridges 8Y, 8M, and 8C for each of the Y, M, and C colors, image formation is not performed in the mono mode, so the number of sheets printed in the full color mode is the printable number. On the other hand, for the process cartridge 8K for K color, image formation is performed in both the full color mode and the mono mode, so the total number of sheets printed in each image forming mode is the printable number. In other words, for the process cartridge 8K for K color, the printable number when forming an image in the full color mode and the mono mode is almost the same as the printable number when forming an image only in the full color mode. Therefore, in this evaluation, the comparison was made using the process cartridges 8Y, 8M, and 8C for each of the Y, M, and C colors, in which the effect of Example 1 is remarkable.

[0103] (Comparison between Example 1 and Comparative Examples 1 and 2) Table 1 shows the evaluation results.

[0104] [Table 1]

[0105] In evaluation mode (1), there was no significant difference between Example 1 and Comparative Examples 1 and 2, the number of printable sheets was almost the same, and low density in the latter half did not occur until the remaining life GJ of the developing roller reached 0%. On the other hand, in evaluation mode (2), differences in the evaluation results appeared between Example 1 and Comparative Examples 1 and 2.

[0106] First, in the evaluation mode (2), in the comparative example 1, when the remaining life of the developing roller GJ reached 0%, the second half density was good, but the number of printable sheets was as low as 1500 sheets. This is because in the comparative example 1, the running distance of the developing roller 42 is counted without distinguishing between the developer contact state and the developer separation state, and the running distance of the developing roller 42 is not corrected. Specifically, the filming state of the developing roller 42 is good, but half of the remaining life of the developing roller GJ is consumed as the running distance of the developing roller 42 in the mono mode, and the number of printable sheets is half of the total number of prints. In this way, if the life judgment is performed earlier than the actual filming state of the developing roller 42 reaches the threshold value, the user will suffer a disadvantage.

[0107] Next, in evaluation mode (2), in comparative example 2, when the remaining life GJ of the developing roller reached 0%, the number of printable sheets was 3000 sheets, and low density in the latter half occurred. This is because in comparative example 2, only the contact travel distance, which is the travel distance of the developing roller 42 in the developing contact state, is counted, and the separation travel distance, which is the travel distance of the developing roller 42 in the developing separated state, is not counted. In other words, the travel distance of the developing roller 42 in mono mode was not taken into consideration in judging the life, and filming of the developing roller 42 progressed, causing low density in the latter half.

[0108] In contrast, in the evaluation mode (2), in Example 1, the running distance of the developing roller 42 is obtained, taking into account the influence of rubbing received by the toner 90 and the influence of filming received by the developing roller 42 in each of the developing contact state and the developing separation state. Then, based on the running distance of the developing roller 42, the life of the developing device 4 is determined. As a result, even when the developing devices 4Y, 4M, and 4C for each color of YMC are often driven in the developing separation state as in the monomode, an appropriate life determination can be made according to the filming state of the developing roller 42 of each developing device 4. Here, let Pf1 be the cumulative number of printed sheets when it is determined that the total cumulative running distance Ht has reached the life by exceeding a predetermined threshold value when the developing device 4 is used only in the full-color mode. Also, let Pf2 be the cumulative number of printed sheets in the full-color mode when it is determined that the total cumulative running distance Ht has reached the life by exceeding a predetermined threshold value when the developing device 4 is used such that the usage ratio of the full-color mode and the monomode is 5:5 on average (executed so that the respective usage ratios are the same on average). At this time, as shown in Table 1, in Example 1, the relationship of Pf1×0.5 < Pf2 < Pf1 is satisfied. Note that in Comparative Examples 1 and 2, this relationship is not satisfied.

[0109] Thus, in the first embodiment, the image forming apparatus 100 includes an image carrier (photosensitive drum) 1 that carries a developer image, a developing device 4 that includes a developer carrier 42 that carries a developer, rotates, and supplies the developer to the image carrier 1 to form a developer image on the image carrier 1, a moving mechanism (contact / separation mechanism) 130 that moves the developer carrier 42 to a first position (contact position) where the developer carrier 42 and the image carrier 1 are in contact with each other, and a second position (separation position) that is further away from the image carrier 1 than the first position, a driving unit 127 that can rotate the developer carrier 42 when the developer carrier 42 is disposed at either the first position or the second position, and an acquisition unit (travel distance calculation device) that acquires information regarding the amount of rotation of the developer carrier 42. The acquiring unit 60 corrects first information (contact travel distance) regarding the amount of rotation of the developer carrier 42 when the developer carrier 42 is arranged at the first position to third information (corrected contact travel distance) using a first correction coefficient (first load correction coefficient) k1, and corrects second information (separation travel distance) regarding the amount of rotation of the developer carrier 42 when the developer carrier 42 is arranged at the second position to fourth information (corrected separation travel distance) using a second correction coefficient (second load correction coefficient) k2 different from the first correction coefficient k1, and the notifying unit 81 performs notification regarding the life of the developing device 4 based on the third information and the fourth information. In the first embodiment, the acquisition unit 60 includes a first information acquisition unit (contact travel distance measurement unit) 61 that acquires the first information, a second information acquisition unit (separation travel distance measurement unit) 62 that acquires the second information, a third information acquisition unit (contact travel distance calculation unit) 63 that corrects the first information using the first correction coefficient k1 to acquire the third information, a fourth information acquisition unit (separation travel distance calculation unit) 64 that corrects the second information using the second correction coefficient k2 to acquire the fourth information, and a fifth information acquisition unit (travel distance calculation unit) 65 that acquires fifth information (total accumulated combined travel distance) regarding a combined rotation amount (combined corrected distance) obtained by accumulating a combined rotation amount (combined travel distance) obtained by combining an amount of rotation indicated by the third information and an amount of rotation indicated by the fourth information, and the notification unit 81 performs notification regarding the life of the developing device 4 based on the fifth information.In the first embodiment, the first information acquisition unit 61 acquires the first information based on the amount of rotation of the developer carrier 42 measured when the developer carrier 42 is disposed at the first position. Also, in the first embodiment, the image forming apparatus 100 has a developer amount acquisition unit (developer amount detection device) 70 that acquires developer amount information related to the amount of developer in the developing device, and the notification unit 81 can further perform notification related to the life of the developing device 4 when the amount of developer remaining in the developing device 4 indicated by the developer amount information becomes equal to or less than a predetermined threshold. Also, in the first embodiment, the absolute value of the first correction coefficient k1 is greater than the absolute value of the second correction coefficient k2.

[0110] As described above, according to the first embodiment, in a configuration in which the developing roller 42 is rotationally driven in the developer separation state, the life of the developing device 4 can be appropriately determined, and the life of the developing device 4 can be appropriately notified.

[0111] [Example 2] Next, a description will be given of Example 2. The basic configuration and operation of the image forming apparatus 100 of Example 2 are the same as those of Example 1. Therefore, in the image forming apparatus of Example 2, elements having the same or corresponding functions or configurations as those of the image forming apparatus 100 of Example 1 are given the same reference numerals as those of Example 1, and detailed descriptions thereof will be omitted.

[0112] The filming of the developing roller 42 may vary depending on the usage environment (ambient environment of the image forming apparatus 100) of the image forming apparatus 100. For example, in a low temperature and low humidity environment, the charge amount of the toner 90 increases, and the electrostatic adhesion force of the toner 90, external additives, etc. may become strong. As a result, when the developing roller 42 is rubbed against the regulating blade 44, the supply roller 43, and the photosensitive drum 1, the toner 90, external additives, etc. may easily adhere to the developing roller 42.

[0113] Therefore, in the second embodiment, the first load correction coefficient k1 and the second load correction coefficient k2 are changed according to the temperature and humidity of the environment in which the image forming apparatus 100 is used.

[0114] <Control mode> 9 is a block diagram showing an outline of a control mode of the image forming apparatus 100 of the embodiment 2. The functional blocks of the control unit 30 in the embodiment 2 are similar to those in the embodiment 1 shown in FIG.

[0115] In the second embodiment, the image forming apparatus 100 has a temperature and humidity sensor 82, which is a temperature and humidity detection unit that detects the temperature and humidity inside the image forming apparatus 100, as an environment detection unit (environment acquisition unit) that detects the usage environment (environment information) of the image forming apparatus 100. In the second embodiment, the control unit 30 calculates the absolute humidity (here, also referred to as "absolute moisture content") [g / m 3 In the second embodiment, the memory 80 provided in the process cartridge 8 stores a first load correction coefficient k1 and a second load correction coefficient k2 that are set according to the classification of the absolute moisture content.

[0116] <Calculating the Travel Distance of the Developing Roller> Next, the calculation of the travel distance of the developing roller 42 in the second embodiment will be described. In the second embodiment, the first load correction coefficient k1 (k1a, k1b) and the second load correction coefficient k2 (k2a, k2b) are set according to the classification of the absolute moisture content as shown in Table 2. In the second embodiment, the information on the first and second load correction coefficients k1 and k2 as shown in Table 2 is stored in the memory 80 provided in the process cartridge 8.

[0117] [Table 2]

[0118] First, similarly to the first embodiment, the contact travel distance measuring unit 61 measures the contact travel distance W1, and the separation travel distance measuring unit 62 measures the separation travel distance W2.

[0119] Next, the contact travel distance calculation unit 63 reads out the first load correction coefficient k1 stored in the memory 80 according to the calculated absolute moisture content. For example, if the absolute moisture content of the environment in which the image forming apparatus 100 is used is 3.0 g / m 3If it is less than k1a, the first load correction coefficient k1 is read out. Then, the contact travel distance calculation unit 63 multiplies the contact travel distance W1 by the first load correction coefficient k1 to calculate the corrected contact travel distance H1. Specifically, the corrected contact travel distance H1 is calculated by the following calculation formula (14). H1 = k1 × W1 (14)

[0120] Similarly, the separation travel distance calculation unit 64 reads out the second load correction coefficient k2 stored in the memory 80 according to the calculated absolute moisture content. For example, when the absolute moisture content of the usage environment of the image forming apparatus 100 is 3.0 g / m 3 If it is less than k2a, k2a is read out as the second load correction coefficient k2. Then, the separation travel distance calculation unit 64 multiplies the separation travel distance W2 by the second load correction coefficient k2 to calculate the corrected separation travel distance H2. Specifically, the corrected separation travel distance H2 is calculated by the following calculation formula (15). H2 = k2 × W2 (15)

[0121] Subsequent calculations of the combined travel distance H and the total accumulated combined travel distance Ht in the travel distance calculation unit 65, and calculation of the remaining life GJ of the developing roller and updating of the accumulated combined travel distance Hr in the life determination unit 81 are the same as in the first embodiment, and therefore will not be described.

[0122] As described above, in the second embodiment, the first load correction coefficient k1 and the second load correction coefficient k2 are changed according to the temperature and humidity of the usage environment of the image forming apparatus 100. This makes it possible to count the travel distance of the developing roller 42 in accordance with the progress of filming on the developing roller 42 in the usage environment of the image forming apparatus 100.

[0123] In the second embodiment, the relationship between the absolute moisture content and the first and second load correction coefficients k1 and k2 as shown in Table 2 is used, but the present invention is not limited to this. For example, the absolute moisture content may be divided into smaller categories than those shown in Table 2, and different first and second load correction coefficients k1 and k2 may be set for each category.

[0124] In the second embodiment, the absolute moisture content is used as an index indicating the usage environment of the image forming apparatus 100, but the present invention is not limited to this. For example, a configuration may be adopted in which the first load correction coefficient k1 and the second load correction coefficient k2 are acquired according to the temperature or humidity category detected by the temperature and humidity sensor 82. If there is a correlation with the progress of filming on the developing roller 42, the usage environment of the image forming apparatus 100 (ambient environment of the image forming apparatus 100) may be at least one of the temperature and humidity inside or outside the image forming apparatus 100.

[0125] <Developing device life determination sequence> Next, a description will be given of a lifespan determination sequence for the developing device 4 in the embodiment 2. Fig. 10 is a flow chart of the lifespan determination sequence for the developing device 4 in the embodiment 2. The control unit 30 performs each process shown in Fig. 10 based on information in the memory 80 provided in the process cartridge 8 to determine the lifespan of the developing device 4, and can notify the user of the result.

[0126] First, when a print signal (start signal, image signal) is sent to the image forming apparatus 100 (S301), the control unit 30 calculates the absolute moisture content of the usage environment of the image forming apparatus 100 based on the detection result of the temperature and humidity sensor 82 (S302). Thereafter, the control unit 30 drives the developing device 4 to start the image forming operation (S303).

[0127] Next, the control unit 30, in the travel distance calculation unit 65, adds (accumulates) the distance Hu to the accumulated combined travel distance Hr stored in the memory 80 for each predetermined total travel distance Hu to calculate a total accumulated combined travel distance Ht (S304). Then, the control unit 30 calculates the remaining life GJ of the developing roller (S305), and writes the total accumulated combined travel distance Ht in the memory 80 as a new accumulated combined travel distance Hr (S306).

[0128] Next, the control unit 30 judges whether the developing roller remaining life GJ is 0% or less (whether it is less than a predetermined remaining life threshold value or not) (S307). If the control unit 30 judges that the developing roller remaining life GJ is 0% or less, it notifies the user by displaying on the operation panel 20 provided in the apparatus main body 110 that the developing device 4 has reached the end of its life (S308). On the other hand, if the control unit 30 judges that the developing roller remaining life GJ is not 0% or less (greater than 0%), the process proceeds to S309.

[0129] The processing in steps S309 to S313 is the same as the processing in steps S108 to S112 in FIG. 6 in the first embodiment, and therefore a description thereof will be omitted.

[0130] Thus, in the second embodiment, the image forming apparatus 100 has an environment acquisition unit (temperature and humidity sensor) 82 that acquires environmental information related to the atmospheric environment of the image forming apparatus 100, and the notification unit 81 performs notification related to the life of the developing device 4 based on the third information (corrected contact travel distance) and the fourth information (corrected separation travel distance) obtained by correcting the first information (contact travel distance) and the second information (separation travel distance) according to the environmental information by the acquisition unit 60. In particular, in the second embodiment, the third information acquisition unit (contact travel distance calculation unit) 63 acquires the third information by correcting the first information using the first correction coefficient k1 according to the environmental information, and the fourth information acquisition unit (separation travel distance calculation unit) 64 acquires the fourth information by correcting the second information using the second correction coefficient k2 according to the environmental information.

[0131] As described above, in the second embodiment, the first load correction coefficient k1 and the second load correction coefficient k2 are changed according to the temperature and humidity of the usage environment of the image forming apparatus 100. As a result, in the second embodiment, the same effects as in the first embodiment can be obtained, and an appropriate lifespan determination can be made according to the progress of filming on the developing roller 42 in the usage environment of the image forming apparatus 100. That is, in the second embodiment, even if the developing devices 4Y, 4M, and 4C for the respective colors of Y, M, and C are often driven in the development separation state as in the mono mode, a more appropriate lifespan determination can be made for each developing device 4 by taking into account the usage environment of the image forming apparatus 100.

[0132] [Example 3] Next, a description will be given of Example 3. The basic configuration and operation of the image forming apparatus 100 of Example 3 are the same as those of Examples 1 and 2. Therefore, in the image forming apparatus of Example 3, elements having the same or corresponding functions or configurations as those of the image forming apparatus 100 of Examples 1 and 2 are denoted by the same reference numerals as those of Examples 1 and 2, and detailed descriptions thereof will be omitted.

[0133] As the image forming apparatus 100 is used, the amount of toner remaining in the developing device 4 decreases, and the opportunities for the same toner 90 to be repeatedly rubbed increase, so that filming of the developing roller 42 is more likely to progress.

[0134] Therefore, in the third embodiment, the total travel distance H of the developing roller 42 is corrected using a third load correction coefficient (third correction coefficient) k3 corresponding to the remaining amount of toner in the developing device 4.

[0135] <Calculating the Travel Distance of the Developing Roller> Next, the calculation of the travel distance of the developing roller 42 in the third embodiment will be described. In the third embodiment, the travel distance calculation unit 65 corrects the total travel distance H of the developing roller 42 by using the third load correction coefficient k3 according to the remaining amount of toner in the developing device 4. In the third embodiment, the third load correction coefficient k3 (k31 to k36) is set according to the remaining amount of toner TJ in the developing device 4 as shown in Table 3. Specifically, the remaining amount of toner in the developing device 4 is divided into a plurality of ranges, and one set value of the third load correction coefficient k3 is assigned to one division. In addition, the third load correction coefficient k3 in one division is assumed to be constant. In the third embodiment, the information on the third load correction coefficient k3 as shown in Table 3 is stored in the memory 80 provided in the process cartridge 8.

[0136] [Table 3]

[0137] First, similarly to the first and second embodiments, the contact travel distance calculation unit 63 and the separation travel distance calculation unit 64 calculate the corrected contact travel distance H1 and the corrected separation travel distance H2, respectively.

[0138] Next, the travel distance calculation unit 65 adds up the corrected contact travel distance H1 and the corrected separation travel distance H2 to obtain a total travel distance H. Specifically, the total travel distance H is calculated by the following calculation formula (16). H = H1 + H2 (16)

[0139] In the third embodiment, the travel distance calculation unit 65 refers to the remaining toner amount TJ calculated by the developer amount detection device 70 and reads out the third load correction coefficient k3 stored in the memory 80 according to the remaining toner amount TJ every time the total travel distance H increases by a predetermined distance Hu. For example, if the remaining toner amount TJ in the developing device 4 is 35%, k33 is read out as the third load correction coefficient k3. In the third embodiment, the predetermined total travel distance Hu is set to about two sheets of A4 paper (approximately 300 mm).

[0140] Next, the mileage calculation unit 65 multiplies the predetermined total mileage Hu by the third load correction coefficient k3 to calculate a corrected total mileage (corrected total rotation amount) Hs. Specifically, the corrected total mileage Hs is calculated by the following calculation formula (17). Hs = k3 × Hu (17)

[0141] Furthermore, the running distance calculation unit 65 adds (integrates) the obtained corrected total running distance Hs to the accumulated total running distance Hr from the start of use of the developing device (process cartridge 8) stored in the memory 80 to calculate the total accumulated total running distance Ht, which is the total corrected distance. Specifically, the total accumulated total running distance Ht is calculated by the following calculation formula (18). Ht = Hr + Hs (18)

[0142] Next, the life determination unit 81 calculates the developing roller remaining life GJ based on the travel distance threshold Wth and the total accumulated combined travel distance Ht stored in the memory 80. Specifically, the developing roller remaining life GJ is calculated by the following calculation formula (19). GJ[%]=(1-Ht / Wth)×100 ···(19)

[0143] Then, the lifespan determination unit 81 writes (updates) the obtained total accumulated combined mileage Ht in the memory 80 as a new accumulated combined mileage Hr.

[0144] As described above, in the third embodiment, the total travel distance H of the developing roller 42 is corrected using the third load correction coefficient k3 according to the remaining amount of toner in the developing device 4. This makes it possible to count the travel distance of the developing roller 42 taking into account the effect on filming of the developing roller 42 when the remaining amount of toner in the developing device 4 becomes low. Specifically, the fewer the remaining amount of toner in the developing device 4, the more opportunities there are for the same toner 90 to be repeatedly rubbed, so the third load correction coefficient k3 is set so that the travel distance of the developing roller 42 increases.

[0145] As described above, in the third embodiment, the value of the third load correction coefficient k3 is set to be larger as the remaining amount of toner decreases. However, this is not limited to this. For example, the same third load correction coefficient k3 may be set for a plurality of sections, or the third load correction coefficient k3 may be set to be smaller as the remaining amount of toner decreases. This is because, depending on the configuration of the developing device 4, the circulation of the toner 90 may be improved in a certain remaining toner amount range, and the effect of the remaining amount of toner decreasing may be mitigated.

[0146] In the third embodiment, the relationship between the remaining toner amount TJ and the third load correction coefficient k3 as shown in Table 3 is used, but the present invention is not limited to this. For example, the range of the remaining toner amount TJ may be subdivided as shown in Table 3, and a different third load correction coefficient k3 may be set for each range, or conversely, the range of the remaining toner amount TJ may be reduced.

[0147] In the third embodiment, the third load correction coefficient k3 is set to a value of 1.0 or more, but is not limited to this. The degree of progress of filming on the developing roller 42 differs depending on, for example, the usage environment of the image forming apparatus 100, the physical properties and shape of the toner 90, and the type, shape, or amount of additives, and the third load correction coefficient k3 may be set to a value less than 1.0.

[0148] <Developing device life determination sequence> Next, a description will be given of a lifespan determination sequence for the developing device 4 in the embodiment 3. Fig. 11 is a flow chart of the lifespan determination sequence for the developing device 4 in the embodiment 3. The control unit 30 performs each process shown in Fig. 11 based on the information in the memory 80 provided in the process cartridge 8 to determine the lifespan of the developing device 4, and can notify the user of the result.

[0149] First, when a print signal (start signal, image signal) is sent to the image forming apparatus 100 (S401), the control unit 30 calculates the absolute moisture content of the usage environment of the image forming apparatus 100 based on the detection result of the temperature and humidity sensor 82 (S402). Thereafter, the control unit 30 drives the developing device 4 to start the image forming operation (S403).

[0150] Next, the control unit 30 refers to the toner remaining amount TJ calculated by the developer amount detector 70 for each predetermined total travel distance Hu in the travel distance calculation unit 65, and reads out the third load correction coefficient k3 stored in the memory 80 according to the toner remaining amount TJ (S404). Then, the control unit 30 multiplies the predetermined total travel distance Hu by the third load correction coefficient k3 in the travel distance calculation unit 65 to calculate the corrected total travel distance Hs (S405). The control unit 30 also adds (integrates) the obtained corrected total travel distance Hs to the accumulated total travel distance Hr stored in the memory 80 to calculate the total accumulated total travel distance Ht (S406). Furthermore, the control unit 30 calculates the remaining life GJ of the developing roller (S407), and writes the total accumulated total travel distance Ht as a new accumulated total travel distance Hr in the memory 80 (S408).

[0151] Next, the control unit 30 judges whether the developing roller remaining life GJ is 0% or less (whether it is less than a predetermined remaining life threshold value or not) (S409). If the control unit 30 judges that the developing roller remaining life GJ is 0% or less, it notifies the user that the developing device 4 has reached the end of its life by displaying this on the operation panel 20 provided in the apparatus main body 110 (S410). On the other hand, if the control unit 30 judges that the developing roller remaining life GJ is not 0% or less (greater than 0%), the process proceeds to S411.

[0152] The processing in steps S411 to S415 is the same as the processing in steps S108 to S112 in FIG. 6 in the first embodiment, and therefore a description thereof will be omitted.

[0153] As described above, in the third embodiment, the notification unit 81 notifies about the life of the developing device 4 based on the third information (corrected contact travel distance) and the fourth information (corrected separation travel distance) obtained by correcting the first information (contact travel distance) and the second information (separation travel distance) according to the developer amount information by the acquisition unit 60. In particular, in the third embodiment, the fifth information acquisition unit (travel distance calculation unit) 65 acquires the fifth information (total accumulated combined travel distance) by integrating a corrected combined rotation amount obtained by correcting the combined rotation amount (combined travel distance) using a third correction coefficient (third load correction coefficient) k3 according to the developer amount information.

[0154] As described above, in the third embodiment, the total travel distance H of the developing roller 42 is corrected using the third load correction coefficient k3 according to the amount of toner remaining in the developing device 4. This makes it possible to perform an appropriate lifespan judgment in accordance with the progression of filming on the developing roller 42 even when the amount of toner remaining in the developing device 4 becomes small as the image forming apparatus 100 is used. That is, in the third embodiment, even if the developing devices 4Y, 4M, and 4C for the respective colors of Y, M, and C are often driven in the development separation state as in the mono mode, a more appropriate lifespan judgment can be performed by taking into account the amount of toner remaining in the developing device 4.

[0155] In the third embodiment, the third load correction coefficient k3 is not changed according to the use environment of the image forming apparatus 100, but the present invention is not limited to this. For example, the third load correction coefficient k3 may be changed according to the absolute moisture amount calculated from the detection result of the temperature and humidity sensor 82, or the temperature or humidity detected by the temperature and humidity sensor 82. Specifically, the third load correction coefficient k3 set according to the toner remaining amount TJ in the developing device 4 and the above-mentioned absolute moisture amount classification is stored in the memory 80 provided in the process cartridge 8. Then, every time the total travel distance H increases by a predetermined distance Hu, the travel distance calculation unit 65 reads out the third load correction coefficient k3 stored in the memory 80 with reference to the toner remaining amount TJ calculated by the developer amount detection device 70 and the absolute moisture amount calculated from the detection result of the temperature and humidity sensor 82. Next, the travel distance calculation unit 65 multiplies the predetermined total travel distance Hu by the third load correction coefficient k3 to calculate the corrected total travel distance Hs.

[0156] In addition, in the third embodiment, by performing correction using the third load correction coefficient k3, when the remaining amount of toner in the developing device 4 becomes small, the progression of the travel distance of the developing roller 42 appears to be faster, and the progression of the developing roller remaining life GJ also becomes faster. Therefore, a correction may be performed using a known method so that the developing roller remaining life GJ does not change suddenly but decreases at a constant rate. For this purpose, for example, the method described in Patent Document 1 can be applied. According to this, the developing roller remaining life WGJ before correction is estimated using the total travel distance when the developing roller remaining life GJ reaches 0% without correction using the third load correction coefficient k3, and the developing roller remaining life GJ is corrected.

[0157] [Example 4] Next, a fourth embodiment will be described. In the fourth embodiment, several modified examples (modified examples 1 to 4) of the image forming apparatus 100 of the first to third embodiments will be described. The basic configuration and operation of the image forming apparatus 100 of each modified example are the same as those of the first to third embodiments. Therefore, in the image forming apparatus of each modified example, elements having the same or corresponding functions or configurations as those of the image forming apparatus 100 of the first to third embodiments are denoted by the same reference numerals as those of the first embodiment, and detailed description thereof will be omitted.

[0158] <Variation 1> A description will be given of Modification 1. The image forming apparatus 100 of Modification 1 is similar to the image forming apparatuses 100 of the first to third embodiments, except for the points described below.

[0159] In Modification 1, the set values ​​of the first load correction coefficients (k1a, k1b) and the second load correction coefficients (k2a, k2b) are all negative values, as shown in Table 4. In Modification 1, information on the first and second load correction coefficients (first and second correction coefficients) k1 and k2 as shown in Table 4 is stored in a memory 80 provided in the process cartridge 8. As shown in Table 4, in Modification 1, the absolute value of the first correction coefficient is larger than the absolute value of the second correction coefficient.

[0160] [Table 4]

[0161] In this case, the travel distance calculation unit 65 performs the same processing as in the first to third embodiments each time the absolute value of the obtained total travel distance H increases by a predetermined distance Hu (each time the total travel distance H decreases by a predetermined distance Hu). In the first modification, the predetermined total travel distance Hu is set to about two sheets of A4 paper (about 300 mm). In the first modification, for example, the travel distance of the developing roller 42 is subtracted from the travel distance of the developing roller 42 corresponding to the end of its life, and when the travel distance of the developing roller 42 becomes equal to or less than a predetermined remaining travel distance threshold (for example, zero), the end of life of the developing device 4 can be determined.

[0162] In this way, even if the set values ​​of the first load correction coefficient and the second load correction coefficient are all negative values, the same effects as those of the first to third embodiments can be obtained.

[0163] <Variation 2> A description will now be given of Modification 2. The image forming apparatus 100 of Modification 2 is similar to the image forming apparatuses 100 of the first to third embodiments, except for the points described below.

[0164] In the second modification, the contact travel distance W1 is calculated by subtracting the separation travel distance W2 from the travel distance W, which is independent of whether the developer contact state or the developer separated state is being established.

[0165] In the second modification, the contact travel distance measuring unit 61 measures the travel distance W based on the drive time Td of the developing device 4, the process speed Ps of the image forming apparatus 100, and the development peripheral speed ratio Sr. Here, in the second modification, the travel distance W is a distance (surface travel distance) that indicates how far a certain point on the surface of the developing roller 42 has advanced (moved) due to the rotation of the developing roller 42, regardless of whether the developing roller 42 is in the development contact state or the development separation state. Specifically, the travel distance W is calculated by the following formula (20). W = Td × Ps × Sr (20)

[0166] In the second modification, the contact travel distance measurement unit 61 calculates the contact travel distance W1 by subtracting the separation travel distance W2 of the developing roller 42 obtained by the separation travel distance measurement unit 62 from the travel distance W. Specifically, the contact travel distance W1 is calculated by the following formula (21). W1 = W - W2 (21)

[0167] The subsequent processing is similar to that in the first to third embodiments, and therefore a description thereof will be omitted.

[0168] Thus, in variant example 2, the first information acquisition unit (contact travel distance measurement unit) 61 acquires the first information (contact travel distance) based on the amount of rotation of the developer carrier 42 measured regardless of whether the developer carrier 42 is positioned at the first position (contact position) or the second position (separated position) and the amount of rotation of the developer carrier 42 measured when the developer carrier 42 is positioned at the second position (separated position).

[0169] With this configuration as well, the same effects as those of the first to third embodiments can be obtained.

[0170] <Variation 3> A description will now be given of Modification 3. The image forming apparatus 100 of Modification 3 is similar to the image forming apparatus 100 of the second and third embodiments, except for the points described below.

[0171] In the third modification, the first load correction coefficient k1 and the second load correction coefficient k2 are each subjected to environmental correction using an environmental correction coefficient z set according to the category of the absolute moisture content.

[0172] In the third modification, the environmental correction coefficient z (za, zb) is set according to the classification of the absolute moisture content, as shown in Table 5. In the third modification, the information on the environmental correction coefficient z as shown in Table 5 is stored in the memory 80 provided in the process cartridge 8.

[0173] [Table 5]

[0174] First, similarly to the second and third embodiments, the contact travel distance measuring unit 61 measures the contact travel distance W1, and the separation travel distance measuring unit 62 measures the separation travel distance W2.

[0175] Next, the contact travel distance calculation unit 63 reads out the first load correction coefficient k1 stored in the memory 80, and also reads out the environmental correction coefficient z stored in the memory 80 according to the calculated absolute moisture content. For example, if the absolute moisture content of the usage environment of the image forming apparatus 100 is 3.0 g / m3 If it is less than z, za is read out as the environmental correction coefficient z. Then, the contact travel distance calculation unit 63 multiplies the contact travel distance W1 by the first load correction coefficient k1 and the environmental correction coefficient z to calculate the corrected contact travel distance H1. Specifically, the corrected contact travel distance H1 is calculated by the following calculation formula (22). H1 = k1 × z × W1 (22)

[0176] Similarly, the separation travel distance calculation unit 64 reads out the second load correction coefficient k2 stored in the memory 80, and also reads out the environmental correction coefficient z stored in the memory 80 according to the calculated absolute moisture content. Then, the separation travel distance calculation unit 64 multiplies the separation travel distance W2 by the second load correction coefficient k2 and the environmental correction coefficient z to calculate the corrected separation travel distance H2. Specifically, the corrected separation travel distance H2 is calculated by the following calculation formula (23). H2 = k2 × z × W2 (23)

[0177] Here, in the third modification, the first load correction coefficient k1 is set to 1.0, and the second load correction coefficient k2 is set to 0.08.

[0178] The subsequent processing is similar to that in the second and third embodiments, and therefore a description thereof will be omitted.

[0179] In this manner, in the third modification, the third information acquisition unit (contact travel distance calculation unit) 63 corrects the first information (contact travel distance) using the first correction coefficient k1 and the environmental correction coefficient z according to the environmental information to acquire the third information (corrected contact travel distance), and the fourth information acquisition unit (separation travel distance calculation unit) 64 corrects the second information (separation travel distance) using the second correction coefficient k2 and the environmental correction coefficient z to acquire the fourth information (corrected separation travel distance).

[0180] With this configuration as well, the same effects as those of the second and third embodiments can be obtained.

[0181] In the third modification, the environmental correction coefficient z shown in Table 5 is used, but the present invention is not limited to this. For example, an environmental correction coefficient z1 for performing environmental correction of the first load correction coefficient and an environmental correction coefficient z2 for performing environmental correction of the second load correction coefficient can be set. These environmental correction coefficients z1 and z2 can be stored in the memory 80 and read out according to the calculated absolute moisture content for use. Furthermore, the absolute moisture content may be divided into smaller categories than those shown in Table 5, and a different environmental correction coefficient z may be set for each category.

[0182] In addition, in the third modification, the absolute moisture content is used as an index showing the usage environment of the image forming apparatus 100, but the present invention is not limited to this. For example, the environmental correction coefficient z may be obtained according to the temperature or humidity category detected by the temperature and humidity sensor 82.

[0183] <Variation 4> A description will now be given of Modification 4. The image forming apparatus 100 of Modification 4 is similar to the image forming apparatus 100 of the third embodiment, except for the points described below.

[0184] In the fourth modification, the contact travel distance W1 and the separation travel distance W2 of the developing roller 42 are corrected using the first load correction coefficient k1 and the second load correction coefficient k2 according to the remaining amount of toner in the developing device 4. In the fourth modification, the first load correction coefficient k1 (k11a to k16a, k11b to k16b) and the second load correction coefficient k2 (k21a to k26a, k21b to k26b) are set as shown in Table 6 according to the remaining amount of toner TJ in the developing device 4. Specifically, the remaining amount of toner in the developing device 4 is divided into a plurality of ranges, and the set values ​​of the first load correction coefficient and the second load correction coefficient are assigned to each range. In addition, the first and second load correction coefficients k1 and k2 in one range are constant. In the fourth modification, the first and second load correction coefficients k1 and k2 according to the remaining amount of toner in the developing device 4 are set according to the absolute moisture content. In the fourth modified example, information on the first and second load correction coefficients k1 and k2 as shown in Table 6 is stored in the memory 80 provided in the process cartridge 8.

[0185] [Table 6]

[0186] First, similarly to the third embodiment, the contact travel distance measuring unit 61 measures the contact travel distance W1, and the separation travel distance measuring unit 62 measures the separation travel distance W2.

[0187] Next, the contact travel distance calculation unit 63 refers to the remaining toner amount TJ calculated by the developer amount detection device 70 and the absolute moisture amount calculated separately, and reads out the first load correction coefficient k1 stored in the memory 80. For example, if the remaining toner amount TJ in the development device 4 is 35% and the absolute moisture amount in the usage environment of the image forming apparatus 100 is 3.0 g / m 3 If it is equal to or greater than this, k13b is read out as the first load correction coefficient k1. Then, the contact travel distance calculation unit 63 multiplies the contact travel distance W1 by the first load correction coefficient k1 to calculate the corrected contact travel distance H1. Specifically, the corrected contact travel distance H1 is calculated by the following calculation formula (24). H1 = k1 × W1 (24)

[0188] Similarly, the separation travel distance calculation unit 64 refers to the remaining toner amount TJ calculated by the developer amount detection device 70 and the absolute moisture amount calculated separately, and reads out the second load correction coefficient k2 stored in the memory 80. For example, when the remaining toner amount TJ in the developing device 4 is 35% and the absolute moisture amount in the usage environment of the image forming apparatus 100 is 3.0 g / m 3 If it is equal to or greater than this, k23b is read out as the second load correction coefficient k2. Then, the separation travel distance calculation unit 64 multiplies the separation travel distance W2 by the second load correction coefficient k2 to calculate the corrected separation travel distance H2. Specifically, the corrected separation travel distance H2 is calculated by the following calculation formula (25). H2 = k2 × W2 (25)

[0189] Next, the travel distance calculation unit 65 adds up the corrected contact travel distance H1 and the corrected separation travel distance H2 to obtain a total travel distance H. Specifically, the total travel distance H is calculated by the following calculation formula (26). H = H1 + H2 (26)

[0190] Furthermore, the running distance calculation unit 65 adds (integrates) the predetermined total running distance Hu to the total accumulated running distance Hr from the start of use of the developing device 4 (process cartridge 8) stored in the memory 80 each time the obtained total running distance H increases by a predetermined distance Hu, thereby calculating a total accumulated total running distance Ht, which is a total correction distance. Specifically, the total accumulated total running distance Ht is calculated by the following calculation formula (27). Ht = Hr + Hu (27)

[0191] In the fourth modification, the predetermined total travel distance Hu is set to approximately two A4 sheets of paper (approximately 300 mm).

[0192] The subsequent processing is the same as in the third embodiment, and therefore the description will be omitted.

[0193] In this manner, in the fourth modified example, the third information acquisition unit (contact travel distance calculation unit) 63 corrects the first information (contact travel distance) using the first correction coefficient k1 corresponding to the developer amount information to acquire the third information (corrected contact travel distance), and the fourth information acquisition unit (separation travel distance calculation unit) 64 corrects the second information (separation travel distance) using the second correction coefficient k2 corresponding to the developer amount information to acquire the fourth information (corrected separation travel distance).

[0194] With this configuration as well, the same effects as those of the third embodiment can be obtained.

[0195] [others] Although the present invention has been described above with reference to specific embodiments, the present invention is not limited to the above-mentioned embodiments.

[0196] Notification of information to the operator is not limited to a display of a message on the display unit, etc. For example, notification may be made by a warning sound or voice generated by a sound generating unit, or by lighting or blinking of a light emitting unit.

[0197] Furthermore, the displays and inputs described above as being performed on the operation panel may be performed on an external device communicably connected to the image forming apparatus.

[0198] Furthermore, the information described above as being stored in a memory that is detachable from the main body of the apparatus together with the developing device may instead be stored in a storage unit provided in the main body of the apparatus.

[0199] In addition, in Examples 2 and 3 and Modifications 1, 3, and 4, the correction coefficient was set on the assumption that filming on the developing roller is more likely to progress in a low-temperature, low-humidity environment than in a high-temperature, high-humidity environment. However, this is not limited to the above, and depending on the device configuration, the characteristics of the toner and external additives, etc., there may be cases where filming on the developing roller is more likely to progress in a high-temperature, high-humidity environment than in a low-temperature, low-humidity environment. In this case, the absolute value of the correction coefficient can be set to be larger in a high-temperature, high-humidity environment than in a low-temperature, low-humidity environment.

[0200] Furthermore, the present invention is also applicable to, for example, a monochrome image forming apparatus having only one developing device, so long as the developer carrier is driven in the developer separation state.

[0201] In the above embodiment, the developing device is capable of moving the developer carrier to and from the image carrier, but is not limited thereto. The image forming device may have a moving mechanism for moving the developer carrier to a first position where the developer carrier contacts the image carrier and a second position that is farther away from the image carrier than the first position, and may be rotated while the developer carrier is disposed at the second position. In addition, the developer carrier may contact the image carrier at the second position, and the developer carrier may be smaller in intrusion amount or smaller in contact pressure at the second position than at the first position. Therefore, the second position is a position where the influence of filming on the developer carrier is smaller than that at the first position. In addition, the developing device is not limited to a device that uses a non-magnetic one-component developer as the developer, and may use a magnetic one-component developer, a two-component developer including a toner and a carrier, or the like.

[0202] In addition, in the above-described embodiment, a configuration has been described in which a drive motor (drive unit, drive source) is common to the image carrier and the developer carrier, but the image carrier and the developer carrier may be driven by separate drive motors (drive unit, drive source). [Explanation of symbols]

[0203] 1 Photosensitive drum 4. Developing device 8 Process cartridge 30 Control section 60 Mileage calculation device 61 Contact mileage measurement unit 62 Distance travel distance measurement unit 63 Contact travel distance calculation section 64 Separation travel distance calculation unit 65 Mileage calculation unit 66 Odometer unit 70 Developer amount detection device 71 Video Counting Unit 72 Developer remaining amount calculation unit 80 Memory 81 Lifespan judgment section 82 Temperature and Humidity Sensor 90 Toner

Claims

1. an image carrier that carries a developer image; a developing device including a developer carrier that carries a developer, rotates, and supplies the developer to the image carrier to form a developer image on the image carrier; a moving mechanism that moves the developer carrier to a first position where the developer carrier and the image carrier are in contact with each other, and a second position that is farther from the image carrier than the first position; a drive unit capable of rotating the developer carrier when the developer carrier is located at either the first position or the second position; an acquiring unit that acquires information including first information regarding a rotation amount of the developer carrier when the developer carrier is located at the first position and second information regarding a rotation amount of the developer carrier when the developer carrier is located at the second position; a control unit that controls the drive unit and the acquisition unit; The control unit (i) controlling the developing device so that the remaining life of the developing device is shortened based on the first information and so that the remaining life of the developing device is shortened based on the second information; (ii) controlling the developing device so as to change the degree of decrease in the remaining life span based on the first information and the degree of decrease in the remaining life span based on the second information; An image forming apparatus characterized by:

2. 2. The image forming apparatus according to claim 1, wherein the acquiring unit acquires the first information based on an amount of rotation of the developer carrier measured when the developer carrier is disposed at the first position.

3. 2. The image forming apparatus according to claim 1, wherein the acquiring unit acquires the first information based on an amount of rotation of the developer carrier measured regardless of whether the developer carrier is positioned at the first position or the second position, and an amount of rotation of the developer carrier measured when the developer carrier is positioned at the second position.

4. an environment acquisition unit that acquires environmental information relating to an ambient environment of the image forming apparatus; a notification unit that notifies information regarding the life of the developing device, 2. The image forming apparatus according to claim 1, wherein the notification unit issues a notification regarding the life of the developing device in accordance with the environmental information.

Images