Image forming apparatus

Abstract

To provide an image forming apparatus having a developing device to which a supply container for supplying developer is removably attached, and to appropriately notify the timing to supply the developer to the developing device and the life of the developing device.SOLUTION: An image forming apparatus comprises: a photoconductor drum, on the surface of which an electrostatic latent image is formed; a developing device that has a storage chamber storing developer and a developing roller supplying the developer from the storage chamber to the photoconductor drum, and to which a supply container for supplying the developer to the storage chamber is removably attached; and notification means that performs a notification to a user. When a cumulative movement distance obtained by integrating the distance of movement of the surface of the developing roller in a predetermined section from the initial stage of use of the developing device, becomes equal to or more than a predetermined first supply determination threshold, the notification means performs a notification to promote the supply of the developer.SELECTED DRAWING: Figure 6(B)

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus. [Background technology]

[0002] In the developing device of an electrophotographic image forming apparatus, the toner carried on the developing roller is constantly rubbed against a supply roller that supplies the toner contained in the developing device to the developing roller and a developing blade that regulates the amount of toner on the developing roller. This rubbing causes external additives and other additives added to the toner to become detached or embedded, and the toner deteriorates as the number of image formations increases. In addition, external additives and fine toner particles that have detached from the toner adhere and accumulate on the surface of the developing roller, causing filming, which reduces the toner carrying capacity and charging ability of the developing roller and leads to image defects.

[0003] Patent Document 1 discloses a method for calculating the amount of deterioration according to the amount of toner remaining in a developing device of an image forming apparatus and determining the lifespan of the developing device. Patent Document 2 discloses a method for changing the weighting of the amount of use of a developing roller depending on the environment in which the image forming apparatus is used, and changing the replacement timing of consumable parts depending on the environment in which the image forming apparatus is used.

[0004] Patent Document 3 describes a developing device that can be replenished with toner from a replenishing container such as a toner pack or a toner bottle. Toner replenishment methods include a method in which toner is gradually replenished as consumed during image formation operations, and a method in which toner is replenished all at once when the toner in the developing device has decreased to a predetermined amount. Some image forming devices that can be replenished with toner suspend image formation operations and notify an operator to replenish toner if toner replenishment continues and the toner is consumed to the point where proper image formation is no longer possible. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4743273 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-161645 [Patent Document 3] Japanese Patent Publication No. 2022-103540 Summary of the Invention [Problem to be solved by the invention]

[0006] In an image forming apparatus having a developing device that can replenish toner from a supply container, as described in Patent Document 3, the deterioration state of the toner in the developing device changes when toner is replenished. Furthermore, the wear state of the developing roller changes depending on the deterioration state of the toner in the developing device. Therefore, unless the appropriate timing for replenishment and the end of life of the developing roller are determined taking into account the deterioration state of the toner due to replenishment and the wear state of the developing roller, fog due to filming on the developing roller and poor density in half-tone images may occur. Patent Documents 1 and 2 do not take into account that replenishment of toner from a supply container to the developing device changes the deterioration state of the toner and the wear state of the developing roller.

[0007] An object of the present invention is to more appropriately notify the timing for replenishment of developer to the developing device and the lifespan of the developing device in an image forming device having a developing device to which a replenishment container for replenishing developer can be attached or detached. [Means for solving the problem]

[0008] The present invention comprises a photosensitive drum on the surface of which an electrostatic latent image is formed; a developing device including a storage chamber for storing a developer and a developing roller for supplying the developer from the storage chamber to the photosensitive drum, the developing device having a detachable supply container for replenishing the developer to the storage chamber; a notification means for notifying a user; Equipped with The image forming device is characterized in that the notification means issues a notification to encourage replenishment of the developer when the cumulative movement distance, calculated by accumulating the movement distance of a specified section of the surface of the developing roller from the beginning of use of the developing device, becomes equal to or greater than a specified first replenishment judgment threshold.

[0009] The present invention comprises a photosensitive drum on the surface of which an electrostatic latent image is formed; a developing device including a storage chamber for storing a developer and a developing roller for supplying the developer from the storage chamber to the photosensitive drum, the developing device having a detachable supply container for replenishing the developer to the storage chamber; a notification means for notifying a user; Equipped with The image forming device is characterized in that the notification means notifies that the developing device has reached the end of its life when the cumulative movement distance, calculated by accumulating the movement distance of a specified section of the surface of the developing roller from the beginning of use of the developing device, becomes equal to or greater than a specified life judgment threshold. [Effects of the Invention]

[0010] According to the present invention, in an image forming device having a developing device to which a supply container for replenishing developer can be attached and detached, it is possible to more appropriately notify the timing for replenishing developer to the developing device and the lifespan of the developing device. [Brief explanation of the drawings]

[0011] [Figure 1] Schematic cross-sectional view of an image forming apparatus [Figure 2(A)] Schematic front view of the toner pack [Figure 2(B)] Schematic cross-sectional view showing a state in which the toner pack is attached to the developing device [Figure 3] 1 is a schematic front view of a light guide member of a toner amount sensor; [Figure 4] Circuit diagram of the toner amount sensor [Figure 5(A)] 1 is a block diagram showing a control system of an image forming apparatus; [Figure 5(B)] 1 is a schematic block diagram showing a control system of an image forming apparatus according to a first embodiment of the present invention; [Figure 6(A)]Flowchart of the supply request / life notification sequence in the first embodiment [Figure 6(B)] Flowchart of the supply request / life notification sequence in the first embodiment [Figure 7] Evaluation experiment results in Example 1 [Figure 8] 10 is a schematic block diagram showing a control system of an image forming apparatus according to a second embodiment of the present invention; [Figure 9(A)] Flowchart of the supply request / life notification sequence in the second embodiment [Figure 9(B)] Flowchart of the supply request / life notification sequence in the second embodiment [Figure 10] Evaluation experiment results in Example 2 [Figure 11] Schematic block diagram showing a control system of an image forming apparatus according to Examples 3 to 5. [Figure 12(A)] Flowchart of the supply request / life notification sequence in the third embodiment [Figure 12(B)] Flowchart of the supply request / life notification sequence in the third embodiment [Figure 13] Correction coefficient in Example 3 [Figure 14] Example of different correction coefficients in the third embodiment [Figure 15] Evaluation experiment results in Example 3 [Figure 16(A)] Flowchart of the supply request / life notification sequence in the fourth embodiment [Figure 16(B)] Flowchart of the supply request / life notification sequence in the fourth embodiment [Figure 17] Relationship between toner supply amount and correction coefficient in the fourth embodiment [Figure 18] Relationship between toner supply amount and running distance threshold between replenishment in the fourth embodiment [Figure 19(A)] Flowchart of the supply request / life notification sequence in the fifth embodiment [Figure 19(B)] Flowchart of the supply request / life notification sequence in the fifth embodiment [Figure 20] Correction coefficient in Example 5 DETAILED DESCRIPTION OF THE INVENTION

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

[0013] Example 1 <General configuration of image forming apparatus> First, a schematic configuration of an image forming apparatus according to a first embodiment will be described. FIG. 1 is a schematic cross-sectional view of an image forming apparatus 100 according to the first embodiment. In the following description, the front-to-rear direction of the image forming apparatus 100 (the left-to-right direction in FIG. 1) is referred to as the X direction, the left-to-right direction (the direction perpendicular to the paper surface of FIG. 1) is referred to as the Y direction, and the vertical direction is referred to as the Z direction. The X and Y directions are parallel to the horizontal direction, and the Y direction is parallel to the rotational axis direction of the photosensitive drum 1, charging roller 2, developing roller 4, supply roller 5, transfer roller 13, etc. The image forming apparatus 100 according to the first embodiment is a monochrome laser printer capable of forming a black and white image on a sheet-like recording material P using an electrophotographic method, and is configured such that a process cartridge 9 is detachably attached to a main body M of the apparatus. Here, the main body M of the apparatus is the components of the image forming apparatus 100 excluding the process cartridge 9. Note that the image forming apparatus to which the present invention can be applied is not limited to the image forming apparatus having the basic configuration shown in the first embodiment. For example, the present invention can also be applied to a color laser printer that has a plurality of detachable process cartridges 9 and forms a full-color image or the like by transferring a plurality of color toner images onto a recording material P using an intermediate transfer body such as an intermediate transfer belt. Also, in the first embodiment, the image forming apparatus 100 is configured so that the process cartridges 9 are detachable, but the present invention can also be applied to an image forming apparatus in which a process unit similar to that constituting the process cartridge 9 in the first embodiment is provided in the apparatus main body.

[0014] The process cartridge 9 has a photosensitive drum 1, which is a rotatable drum-type (cylindrical) photosensitive member (electrophotographic photosensitive member) serving as an image carrier on whose surface an electrostatic latent image is formed. The process cartridge 9 also has a charging roller 2, which is a roller-type charging member serving as charging means, and a developing device 8 serving as developing means, around the photosensitive drum 1. The process cartridge 9 also has a brush member 12 serving as a paper dust collecting member and a static eliminator 11 serving as static eliminator, around the photosensitive drum 1. The process cartridge 9 also has a memory 15 serving as nonvolatile storage means. The process cartridge 9 also has a toner amount sensor 20 serving as developer amount detection means. The charging roller 2, the developing roller 4 serving as a developer carrier provided in the developing device 8, and the brush member 12 are positioned in contact with the surface (outer periphery) of the photosensitive drum 1. The process cartridge 9 is configured so that it can be easily attached to and detached from the apparatus main body M as a whole via attachment means (not shown), such as attachment guides and positioning members, provided on the apparatus main body M and the process cartridge 9.

[0015] The image forming apparatus 100 also includes a transfer roller 13, which is a roller-type transfer member serving as a transfer means, an exposure device 10 serving as an exposure means, and a fixing device 14 serving as a fixing means. The transfer roller 13 is disposed in contact with the surface of the photosensitive drum 1.

[0016] Furthermore, the image forming apparatus 100 has a control unit 200 that controls the entire image forming apparatus 100, an operation panel 60 as an operation unit, etc. The operation panel 60 has a display unit for displaying information to an operator such as a user or a service representative under the control of the control unit 200, an input unit for inputting information to the control unit 200 in response to an operation by the operator, etc. It is composed of the following.

[0017] <Image formation operation> Next, an image forming operation in the image forming apparatus 100 of the first embodiment will be described. The photosensitive drum 1 receives a driving force from a driving motor (not shown) serving as a driving source constituting a driving means provided in the apparatus main body M, and is driven to rotate in the direction of arrow R1 in the drawing (counterclockwise direction) at a predetermined process speed. Here, the process speed corresponds to the peripheral speed (surface moving speed) of the photosensitive drum 1, and the process speed in the first embodiment is 140 rpm.

[0018] The charging roller 2 contacts the surface of the photosensitive drum 1 with a predetermined contact pressure to form a charging portion. A predetermined charging voltage (charging bias), which is a DC voltage, is applied to the charging roller 2 from a charging voltage application circuit (not shown) provided in the apparatus main body M as a charging voltage application means. As a result, the charging roller 2 uniformly charges the surface of the photosensitive drum 1 to a predetermined potential of a predetermined polarity (negative polarity in Example 1). In Example 1, a charging voltage of −1400 V is applied to the charging roller 2 so that the surface potential (pre-exposure potential VD) of the photosensitive drum 1 becomes −800 V. Note that, although a DC voltage is used as the charging voltage in Example 1, the present invention is not limited to this, and an oscillating voltage in which a DC voltage and an AC voltage are superimposed may also be used as the charging voltage.

[0019] The uniformly charged surface of the photosensitive drum 1 is irradiated and scanned with laser light by the exposure device 10 based on image information, and an electrostatic latent image (electrostatic image) is formed on the photosensitive drum 1. In the first embodiment, the exposure device 10 is configured as a scanner unit. Image information input to the image forming apparatus 100 from an external device (not shown), such as a personal computer connected to the image forming apparatus 100, is converted into a time-series electrical digital image signal by a video controller 206 provided in the image forming apparatus 100. The exposure device 10 is controlled by the control unit 200 to emit laser light modulated in accordance with the time-series electrical digital image signal, and scans and exposes the surface of the photosensitive drum 1. As a result, an electrostatic latent image corresponding to the image information is formed on the photosensitive drum 1. In the first embodiment, the exposure device 10 is configured to emit a light amount of 0.45 μJ / cm so that the post-exposure potential VL of the surface of the photosensitive drum 1 is −100 V. 2The surface of the photosensitive drum 1 is irradiated with laser light.

[0020] The electrostatic latent image formed on the photosensitive drum 1 is developed (visualized) by the developing device 8, which supplies toner 3 as a developer, and a toner image (toner image, developer image) is formed on the photosensitive drum 1. The developing device 8 has a developing roller 4 as a developer carrier. The developing roller 4 contacts the surface of the photosensitive drum 1 with a predetermined contact pressure to form a developing portion. A toner layer is formed on the developing roller 4 by toner 3 charged to a predetermined polarity (negative polarity in Example 1). A predetermined developing voltage (developing bias), which is a DC voltage, is applied to the developing roller 4 from a developing voltage application circuit (not shown) serving as a developing voltage application means provided in the device main body M. As a result, the toner 3 adheres to the electrostatic latent image on the photosensitive drum 1 in the developing portion. As a result, a toner image is formed on the photosensitive drum 1. In Example 1, a developing voltage of −400 V is applied to the developing roller 4. In Example 1, toner 3 charged with the same polarity as the charge polarity of the photosensitive drum 1 (negative polarity in Example 1) adheres to the exposed portion (image portion) on the photosensitive drum 1, where the absolute value of the potential has been reduced by exposure after being uniformly charged (reverse development method). In Example 1, the normal charge polarity of the toner 3, which is the main charge polarity of the toner 3 during development, is negative polarity.

[0021] The transfer roller 13 contacts the photosensitive drum 1 with a predetermined contact pressure to form a transfer portion. The toner image formed on the photosensitive drum 1 is transferred to the recording material P, which is being conveyed while being sandwiched between the photosensitive drum 1 and the transfer roller 13, in the transfer portion. During transfer, a predetermined transfer voltage (transfer bias), which is a DC voltage, is applied to the transfer roller 13 from a transfer voltage application circuit (not shown) as a transfer voltage application means. In the first embodiment, the transfer roller 13 is biased at +150 A transfer voltage of 0V is applied.

[0022] Recording material P (transfer material, recording medium, sheet) is supplied from a feeding section 30 to the transfer section. The feeding section 30 is configured to have a cassette 31 as a recording material storage section, a feeding roller 32 as a feeding member, and the like. The recording material P stored in the cassette 31 is separated one by one by the feeding roller 32 and sent out from the cassette 31. This recording material P is transported to the transfer section by a transport roller 50 (registration roller) as a transport member so as to synchronize with the toner image on the photosensitive drum 1.

[0023] The recording material P onto which the toner image has been transferred is conveyed to a fixing device 14 serving as a fixing means. The fixing device 14 applies heat and pressure to the recording material P to fix (melt and adhere) the toner image onto the recording material P. The recording material P onto which the toner image has been fixed is discharged (output) onto a tray 40 serving as a discharge unit provided outside the apparatus main body M.

[0024] Meanwhile, toner (transfer residual toner) remaining on the photosensitive drum 1 without being transferred to the recording material P during the transfer process is removed from the photosensitive drum 1 as follows: After the transfer process, the surface of the photosensitive drum 1 is neutralized by a neutralization device 11 (discharge lamp) so that the surface potential is 0 V, and then the photosensitive drum 1 enters the charging section. The transfer residual toner remaining on the photosensitive drum 1 includes a mixture of positively charged toner and negatively charged toner that does not have a sufficient charge. This transfer residual toner is negatively charged by discharge in the charging section. The transfer residual toner negatively charged in the charging section reaches the developing section as the photosensitive drum 1 rotates. Here, an electrostatic latent image corresponding to the image information is formed on the surface of the photosensitive drum 1 that has reached the developing section. The transfer residual toner adhering to the non-exposed areas (non-image areas) of the photosensitive drum 1 moves from the photosensitive drum 1 to the developing roller 4 in the developing section due to the potential difference between the pre-exposure potential VD on the photosensitive drum 1 and the development voltage, and is then collected in the developing chamber 8b of the developing device 8. The toner collected in the developing chamber 8b is reused for image formation. Meanwhile, the residual toner adhering to the exposed area (image area) on the photosensitive drum 1 does not move from the photosensitive drum 1 to the developing roller 4 in the developing section, but forms a toner image together with the toner that has moved from the developing roller 4 to the photosensitive drum 1. Then, this toner is transferred onto the recording material P in the transfer section and removed from the photosensitive drum 1.

[0025] In addition, a brush member 12 is provided as a paper dust collecting member to remove paper dust fibers generated from the recording material P that adhere to the photosensitive drum 1 from the recording material P during the transfer process. The brush member 12 is arranged so as to come into contact with the photosensitive drum 1 downstream of the transfer unit in the rotation direction of the photosensitive drum 1 and upstream of the charging unit. As the photosensitive drum 1 rotates, the brush member 12 rubs against the surface of the photosensitive drum 1, thereby picking up and removing the paper dust fibers from the photosensitive drum 1.

[0026] <Detailed configuration of developing device 8> Next, a detailed configuration of the developing device 8 in the image forming apparatus 100 of the first embodiment will be described. In the first embodiment, the developing device 8 is a one-component contact developing device that uses a non-magnetic one-component developer (toner) as a developer. The developing device 8 has a developing container 80 (frame body) that includes a developing chamber 8b as a developing member storage chamber and a toner storage chamber 8a as a storage chamber for storing the developer. The developing chamber 8b and the toner storage chamber 8a are in communication with each other through an opening. The developing chamber 8b is provided with a developing roller 4 as a developer carrier (developing member) that supplies toner from the toner storage chamber 8a to the photosensitive drum 1, and a supply roller 5 as a supply member that supplies toner 3 to the developing roller 4. The developing chamber 8b is also provided with a developing blade 6 as a regulating member that regulates the amount of toner on the developing roller 4 while applying a charge of a predetermined polarity to the toner 3 on the developing roller 4. The developing roller 4 is rotatably disposed in the opening of the developing chamber 8b (developing container 80), and rotates while carrying the toner 3, thereby transferring the toner 3 to the developing chamber 8b (developing container 80). The toner 3 is transported from the inside of the toner storage chamber 8a to the outside of the developing chamber 8b. The toner storage chamber 8a contains toner 3 as a developer. The toner storage chamber 8a is provided with an agitating member 7 for agitating the toner 3 in the toner storage chamber 8a and transporting the toner 3 from the toner storage chamber 8a to the developing chamber 8b.

[0027] In the first embodiment, the developing device 8 uses a contact development system in which the image carrier and the developer carrier are arranged in contact with each other, but the invention is not limited to this. The developing device 8 may use a two-component development system that uses a two-component developer, or a non-contact development system in which the image carrier and the developer carrier are arranged opposite each other with a predetermined gap between them.

[0028] In Example 1, the developing roller 4 is configured by coating a base layer of silicone rubber and a surface layer of urethane rubber in this order on the outer periphery of a core metal having a diameter of 6 mm so that the outer diameter becomes 15 mm. Also, in Example 1, the electrical resistance value of the developing roller 4 is 1×10 4 ~1×10 12 It is Omega.

[0029] In Example 1, the supply roller 5 is a conductive elastic sponge roller formed by forming a foam layer on the outer periphery of a core metal having a diameter of 6 mm. In Example 1, the electrical resistance of the supply roller 5 is 1×10 4 ~1×10 8 The hardness of the supply roller 5 is measured by the load when a flat plate having a longitudinal width of 50 mm is inserted 1 mm into the surface of the supply roller 5.

[0030] In Example 1, the developing blade 6 is a 0.1 mm thick SUS sheet metal made of metal, having a predetermined length in both a longitudinal direction aligned with the rotational axis of the developing roller 4 and a lateral direction substantially perpendicular to the longitudinal direction. This developing blade 6 is disposed so that its free end in the lateral direction faces upstream in the rotational direction of the developing roller 4, and the side surface near the free end contacts the developing roller 4 along the longitudinal direction. In Example 1, the developing blade 6 is made by cutting the tip (free end) of a SUS sheet metal from the side that contacts the developing roller 4. The tip portion of the developing blade 6 is bent in the cutting direction by the cutting process, and the amount of bending of the tip of the developing blade 6, which corresponds to the radius of curvature R, is 0.02 mm.

[0031] The movement of toner 3 in developing device 8 during operation will be described. A driving force is transmitted to developing device 8 from a drive motor (not shown) serving as a driving source constituting a driving means provided in device main body M. This causes developing roller 4, supply roller 5, and agitating member 7 to rotate in the directions indicated by arrows R2 (clockwise), R3 (clockwise), and R4 (counterclockwise), respectively. Note that a common driving source may be used for photosensitive drum 1 and each of the rotating members of developing device 8 (developing roller 4, supply roller 5, and agitating member 7). As agitating member 7 in toner storage chamber 8a rotates, toner 3 in toner storage chamber 8a is agitated and transported toward supply roller 5 in developing chamber 8b. The toner 3 held in the foam layer of supply roller 5 is transported to the contact point with developing roller 4 by the rotation of supply roller 5. At this contact point, the toner 3 is rubbed by the surfaces of developing roller 4 and supply roller 5, which are moving in opposite directions, and some of the toner adheres to the surface of developing roller 4. In Example 1, a configuration was exemplified in which the developing roller 4 and the supply roller 5 move in opposite directions at the contact point, but it may also be a configuration in which the supply roller 5 moves in the forward direction by rotating in the opposite direction (counterclockwise) to the arrow R3.

[0032] The toner 3 adhering to the surface of the developing roller 4 is sent to the contact point with the developing blade 6 as the developing roller 4 rotates. The developing blade 6 regulates the amount of toner 3 adhering to the surface of the developing roller 4 to form a uniform thin layer, and also frictionally charges the toner 3. The thin layer of toner 3 is sent to the contact point with the photosensitive drum 1 as the developing roller 4 rotates, and is used to develop the electrostatic latent image formed on the photosensitive drum 1. The toner 3 on the surface of the developing roller 4 that is not used for development is The toner 3 remaining on the developing roller 4 is transported to the contact point with the supply roller 5 and is removed from the surface of the developing roller 4 by the supply roller 5. The removed toner 3 is sent into the toner storage chamber 8a and is stirred and mixed with the toner 3 in the toner storage chamber 8a.

[0033] <Toner supply configuration> Next, a configuration for supplying toner to the developing container 80 of the developing device 8 in the first embodiment will be described. The developing device 8 is detachably provided with a toner pack 16, which is a supply container for supplying toner to the toner storage chamber 8a. Fig. 2(A) is a schematic front view of the toner pack 16 as a toner supply container in the first embodiment. Fig. 2(B) is a schematic cross-sectional view showing the toner pack 16 attached to the developing container 80 of the developing device 8.

[0034] As shown in Figures 1 and 2(B), a supply protrusion 8c is formed in the developing container 80. The supply protrusion 8c is hollow and communicates with the toner storage chamber 8a via a supply port 8d. A top cover 17 is provided on the top of the apparatus main body M in an openable and closable manner. The upper surface of the top cover 17 forms the tray 40 described above.

[0035] As shown in FIG. 2A, in the first embodiment, the toner pack 16 includes a plastic wrapper 16a that is easily deformed and a connecting portion 16b provided at one end of the wrapper 16a. The interior of the wrapper 16a is connected to the interior of the connecting portion 16b. As shown in FIG. 2B, the image forming apparatus 100 is configured such that the supply protrusion 8c is exposed to the outside when the top cover 17 is opened upward. The toner pack 16 can be attached to the end of the supply protrusion 8c. When the toner pack 16 is attached to the supply protrusion 8c, toner can be replenished from the toner pack 16 to the toner storage chamber 8a. When the top cover 17 is open, the toner pack 16 is connected to the supply protrusion 8c by the connecting portion 16b, and is attached to the supply protrusion 8c with at least a portion of the end of the wrapper 16a opposite the connecting portion 16b exposed to the outside of the image forming apparatus 100. 1 and 2(B), the top cover 17, which is an opening / closing member for exposing the supplying protrusion 8c to the outside, also serves as the tray 40. However, the present invention is not limited to this configuration. For example, the top cover 17 may be configured so that only the top of the supplying protrusion 8c can be opened.

[0036] When the toner pack 16 is attached to the supply protrusion 8c, the inside of the toner pack 16 (wrap 16a, connecting portion 16b) and the inside of the supply protrusion 8c are connected to each other. The toner stored in the toner pack 16 is discharged into the supply protrusion 8c from an opening (not shown) provided in the connecting portion 16b of the toner pack 16, and the toner is supplied from the supply protrusion 8c to the toner storage chamber 8a through the supply port 8d.

[0037] In the first embodiment, the toner supply container is configured with a plastic wrapper that is easily deformed, but this is not limited thereto. For example, the toner supply container may be configured with a bottle container having a substantially conical or cylindrical shape. Furthermore, for example, the toner supply container may be configured with a paper container. Furthermore, the method of discharging the toner 3 from the toner supply container is preferably such that, in the case of the toner pack 16 or a paper container as in the first embodiment, the operator squeezes the container with his / her fingers. In the case of a bottle container, it is preferably such that the operator vibrates the container by tapping it, for example. Furthermore, a discharging mechanism may be provided in the bottle container to discharge the toner 3 from the bottle container. Furthermore, the discharging mechanism may be configured to engage with a drive mechanism provided in the apparatus main body M of the image forming apparatus 100 and receive drive power from the drive mechanism.

[0038] In addition, to prevent toner leakage from the toner supply container, a rotating or sliding shutter member may be provided on the toner supply container. The shutter member may be configured to be destroyed when attached to the supply port 8d of the developing device 8, or may have a removable lid structure such as a seal.

[0039] <Toner amount sensor> Next, a description will be given of toner amount sensor 20 as developer amount detection means for detecting the amount of toner (remaining toner amount) in developing device 8 in embodiment 1. FIG. 3 is a schematic front view of light guiding member 18 constituting toner amount sensor 20 in embodiment 1. FIG. 4 is a circuit diagram of sensor unit 19 constituting toner amount sensor 20 in embodiment 1. FIG. 5 is a schematic block diagram showing a control system of image forming apparatus 100 in embodiment 1, where FIG. 5(A) shows a schematic configuration of control unit 200 and FIG. 5(B) shows a schematic functional block diagram of control unit 200.

[0040] As shown in FIG. 1, developing device 8 is provided with light-guiding member 18 that constitutes toner amount sensor 20. As shown in FIG. 3, light-guiding member 18 has light-emitting side light-guiding section 18a and light-receiving side light-guiding section 18b. Light-emitting side light-guiding section 18a guides light emitted from light-emitting element 19a of sensor section 19, which will be described later, into the interior of developing container 80. Light-receiving side light-guiding section 18b guides light that has passed through light-emitting side light-guiding section 18a and spatial light path Q inside developing container 80, to light-receiving element 19b of sensor section 19, which will be described later.

[0041] As shown in FIG. 1, the developing device 8 is provided with a sensor unit 19 that constitutes the toner amount sensor 20. As shown in FIG. 4, the sensor unit 19 includes a light-emitting element 19a, a light-receiving element 19b, and a substrate (not shown) on which the light-emitting element 19a and the light-receiving element 19b are provided. In the first embodiment, an LED is used as the light-emitting element 19a, and a phototransistor is used as the light-receiving element 19b. The phototransistor is turned on by light from the LED. A cable connector (not shown) is also provided on the substrate, and the sensor unit 19 is connected to a control unit 200 (described later) provided in the apparatus main body M of the image forming apparatus 100 via the cable connector.

[0042] Next, the arrangement of toner amount sensor 20 in Example 1 will be described. Toner amount sensor 20 (light guiding member 18 and sensor unit 19) is arranged on the side surface of toner storage chamber 8a of developer container 80. In Example 1, toner amount sensor 20 (light guiding member 18 and sensor unit 19) is provided in the center of toner storage chamber 8a (developer container 80) in the Y direction. The longitudinal direction of toner storage chamber 8a is parallel to the Y direction. Toner inside toner storage chamber 8a may be unevenly distributed in the longitudinal direction of toner storage chamber 8a, but the uneven distribution of toner is less in the longitudinal center of toner storage chamber 8a. Therefore, by providing toner amount sensor 20 (light guiding member 18 and sensor unit 19) in the longitudinal center of toner storage chamber 8a, the amount of toner can be detected while the influence of uneven distribution of toner is suppressed.

[0043] Next, a method for detecting the toner amount using toner amount sensor 20 will be described. In FIG. 4, a switch (not shown) is provided between light-emitting element 19a and power supply voltage Vcc. When this switch is turned on, voltage is applied from power supply voltage Vcc to light-emitting element 19a, bringing light-emitting element 19a into a conductive state. Meanwhile, a switch (not shown) is also provided between light-receiving element 19b and power supply voltage Vcc. When this switch is turned on, light-receiving element 19b is brought into a conductive state, and a current corresponding to the amount of light detected by light-receiving element 19b flows. Light-emitting element 19a is connected to power supply voltage Vcc and current-limiting resistor R1, and light-emitting element 19a emits light with a current determined by current-limiting resistor R1. Light emitted from light-emitting element 19a passes through spatial optical path Q and is received by light-receiving element 19b. A collector terminal of light-receiving element 19b is connected to power supply voltage Vcc, and a detection resistor R2 is connected to an emitter terminal of light-receiving element 19b. The light receiving element 19b, which is a phototransistor, receives the light emitted from the light emitting element 19a and outputs a signal (current) according to the amount of light received. This signal is converted into a voltage V1 by the detection resistor R2 and input to an A / D conversion unit 202 (described later) of the control unit 200. That is, the light receiving element 19b detects the amount of light in the toner storage chamber 8a. The output value changes depending on the amount of toner stored in the toner amount sensor 20. Electric power is supplied to the toner amount sensor 20 from a power source provided in the main body M of the apparatus.

[0044] A toner amount calculation unit 300 (described later) of the control unit 200 determines whether the light-receiving element 19b has received light from the light-emitting element 19a based on the voltage level input to the control unit 200 by the toner amount sensor 20 and converted into a digital signal by the A / D conversion unit 202. The toner amount calculation unit 300 then calculates the length of time during which the toner amount sensor 20 detected light when the toner 3 in the developing container 80 was stirred by the stirring member 7 for a predetermined time. A ROM 203 (described later) of the control unit 200 stores toner amount determination information for determining (calculating, predicting, estimating) the toner amount in advance as a table showing the relationship between the time and the toner amount. The toner amount calculation unit 300 then calculates the amount of toner in the developing container 80 based on the voltage level input to the control unit 200 by the toner amount sensor 20 and converted by the A / D conversion unit 202, and the information in the table.

[0045] The toner amount calculation unit 300 stores the amount of toner in the developing container 80 calculated based on the detection result by the toner amount sensor 20 in the memory 15. In the first embodiment, the memory 15 stores in advance the remaining amount T of toner stored in the toner storage chamber 8a when the developing device 8 (process cartridge 9) is new (initially used, unused state).

[0046] In the first embodiment, when an image forming operation is performed, the toner amount calculation unit 300 calculates the remaining toner amount T' most recently detected by the toner amount sensor 20 at the end of the image forming operation. If the calculated remaining toner amount T' is smaller than the remaining toner amount T stored in the memory 15, the toner amount calculation unit 300 updates the remaining toner amount T stored in the memory 15 to T' (stores T=T' in the memory 15). Furthermore, when a supply operation is performed to supply toner from the toner pack 16 to the developing device 8, the toner amount calculation unit 300 calculates the remaining toner amount T'' detected by the toner amount sensor 20 during the supply operation. If the calculated remaining toner amount T'' is larger than the remaining toner amount T stored in the memory 15, the toner amount calculation unit 300 updates the remaining toner amount T stored in the memory 15 to T'' (stores T=T'' in the memory 15). This makes it possible to prevent erroneous detection of an increase in the toner amount during an image forming operation and erroneous detection of a decrease in the toner amount during a supply operation.

[0047] In the first embodiment, the toner amount is calculated from the time when light is detected, but it is also possible to use a method of calculating the toner amount from pixel count information of an image, a method of calculating the toner amount from electrostatic capacitance, etc. The method is not limited to these as long as it can calculate the toner amount.

[0048] <Control configuration> As shown in FIG. 5A, the apparatus main body M of the image forming apparatus 100 is provided with a control unit 200 as a control means. The control unit 200 is configured with a CPU 201 as a calculation processing means which is a central element for performing calculation processing, an A / D conversion unit 202, a ROM 203 and a RAM 204 as storage means (storage media), an input / output circuit 205, etc. The A / D conversion unit 202 converts an analog signal input to the control unit 200 into a digital signal. The ROM 203 stores a control program, a pre-determined data table, etc. The RAM 204 stores information input to the control unit 200, detected information, calculation results, etc. The input / output circuit 205 controls the input and output of signals between the control unit 200 and devices connected thereto.

[0049] The control unit 200 is connected to each part of the image forming apparatus 100 (various driving devices, various power sources, various sensors, etc.). The control unit 200 communicates bidirectionally with each part of the image forming apparatus 100 to control the operation of each part. The control unit 200 controls the operation of each part in response to an operation by an operator. Based on signals (start signal, image signal) input from an external device (not shown) such as a printer, the image forming apparatus 100 controls each part of the image forming apparatus 100 to perform an image forming operation.

[0050] 5(B), in the first embodiment, the control unit 200 has a toner amount calculation unit 300. The toner amount calculation unit 300 calculates the amount of toner (remaining toner amount) in the developing container 80 based on the detection result by the toner amount sensor 20 as described above. In the first embodiment, the toner amount calculation unit 300 is realized by the CPU 201 executing a program stored in the ROM 203.

[0051] As shown in FIG. 5B, in the first embodiment, the control unit 200 includes a developing roller travel distance detection unit 400 as a developing roller travel distance detection unit. The developing roller travel distance detection unit 400 includes a developing roller travel distance measurement unit 401 that counts the travel distance of the developing roller 4 as development drive information related to the travel distance of the surface of the developing roller 4. Hereinafter, in this specification, "travel of the developing roller" means the rotation of the developing roller, and "travel distance of the developing roller" is defined as the distance the surface of the developing roller has advanced due to the rotation. Therefore, the "travel distance of the developing roller" can be rephrased as "surface travel distance of the developing roller" or "number of rotations of the developing roller." The developing roller travel distance detection unit 400 also includes a total travel distance calculation unit 402 that calculates, as development drive information, the cumulative travel distance of the developing roller 4 since the start of use (initial use) of the developing device 8. In the first embodiment, the developing roller travel distance detection unit 400 (developing roller travel distance measurement unit 401, total travel distance calculation unit 402) is realized by the CPU 201 executing a program stored in the ROM 203.

[0052] The control unit 200 has a determination unit 500 including a replenishment request processing unit 501 and a life determination processing unit 502. The replenishment request processing unit 501 displays information on the operation panel 60 as a replenishment request notification, urging the operator to perform a replenishment operation. The replenishment request processing unit 501 also detects (recognizes) that a replenishment operation has been performed based on a signal input from the operation panel 60 in response to an operation by the operator. The replenishment request processing unit 501 may also be configured to detect that a replenishment operation has been performed based on the opening and closing of the top cover 17 or the detection result of the toner amount. In the first embodiment, the replenishment request processing unit 501 is realized by the CPU 201 executing a program stored in the ROM 203.

[0053] The lifespan determination processing unit 502 displays information indicating a lifespan notification to the operator on the operation panel 60. The lifespan notification is information notification that informs the operator that the developing device 8 has reached the end of its lifespan and that proper images may not be printed even if replenishment is performed. The lifespan determination processing unit 502 detects (recognizes) that the process cartridge 9 has been replaced based on a signal input from the operation panel 60 in response to an operation by the operator. The lifespan determination processing unit 502 may also detect the replacement of the process cartridge 9 based on the opening and closing of an opening / closing member (not shown) provided in the apparatus main body M for replacing the process cartridge 9. The top cover 17 may also serve as the opening / closing member for replacing the process cartridge 9. In other words, the process cartridge 9 may be configured to be replaceable with the top cover 17 shown in FIG. 2B open. The replacement of the process cartridge 9 may also be detected based on information communication between the control unit 200 of the apparatus main body M and the memory 15 of the process cartridge 9. In the first embodiment, the lifespan determination processing unit 502 is realized by the CPU 201 executing a program stored in the ROM 203.

[0054] The control unit 200 functions as a notification means, which notifies the user via the operation panel 60 to urge them to replenish toner and notifies that the developing device 8 has reached the end of its life based on the processing results of the replenishment request processing unit 501 and the life judgment processing unit 502.

[0055] In the first embodiment, the process cartridge 9 is provided with a memory 15, which is a non-volatile storage means. The control unit 200 can read and write information from and to the memory 15 of the process cartridge 9. The memory 15 stores information related to the calculation of the usage status (usage history) of the developing device 8 and the replenishment request notification, such as information about the toner amount, information about the threshold value related to the toner amount, information about the travel distance of the developing roller 4, and information about the threshold value related to the travel distance of the developing roller 4. This makes it possible to appropriately control the process cartridge 9 (developing device 8) based on the information stored in the memory 15, even when the power of the apparatus main body M is turned on / off or the process cartridge 9 is attached or detached. However, the present invention is not limited to this, and the information stored in the memory 15 in the first embodiment may be stored in a memory provided in, for example, the control unit 200 of the apparatus main body M.

[0056] <Developing roller travel distance detection control> Next, a description will be given of developing roller travel distance detection control for detecting the travel distance of the developing roller 4 in Example 1. In Example 1, the total travel distance TotalL is calculated, which is a value equivalent to the cumulative travel distance obtained by adding up the travel distance of the developing roller 4 from the beginning of use to the present, by adding up the travel distance of the developing roller 4 for each predetermined section (predetermined developing roller travel distance) L. The travel distance of the developing roller 4 for the predetermined section is, for example, the travel distance of the surface of the developing roller 4 from the start to the end of an image forming operation.

[0057] <Supply requirement / lifespan judgment threshold> Next, the replenishment request determination threshold and the life determination threshold in the first embodiment will be described.

[0058] In the first embodiment, the operator can perform the replenishment operation at any time. However, if the developer container 80 is not replenished with toner for a long period of time, problems that lead to poor images, such as filming on the developing roller 4, can occur. Filming is a phenomenon in which developer and external additives added to the developer accumulate on the developing roller, reducing the surface roughness of the developing roller and increasing the electrical resistance of the developing roller. This filming not only makes it impossible to obtain appropriate image density, but also causes fog and uneven density in halftones.

[0059] Therefore, the image forming apparatus 100 of the first embodiment issues a replenishment request notification to the operator to prompt the operator to replenish toner from the toner pack 16 to the developing device 8, based on the remaining toner amount T in the developing container 80 and the total travel distance TotalL as development drive information. The remaining toner amount T is remaining amount information that is information related to the amount of toner contained in the toner storage chamber 8a. The total travel distance TotalL is development drive information that is information related to the movement distance of the surface of the developing roller 4.

[0060] In the first embodiment, the replenishment request processing unit 501 and the lifespan determination processing unit 502 make the determination using three thresholds (toner remaining amount threshold Tth, total travel distance threshold TotalLth, and replenishment execution travel distance threshold L1th) as follows.

[0061] The replenishment request processing unit 501 calculates the printable remaining toner amount Tj based on the remaining toner amount (total toner amount) T in the developing container 80 using the remaining toner amount threshold Tth as the replenishment determination threshold value, according to the following formula (1). Tj=T-Th formula (1)

[0062] The life determination processing unit 502 calculates a printable total travel distance TotalLj based on the travel distance (total travel distance TotalL) that the developing roller 4 has traveled since the start of use of the developing container 80 until the present. The printable total travel distance TotalLj is calculated by using the total travel distance as a life determination threshold. The distance threshold TotalLth (in the first embodiment, a travel distance equivalent to 25,000 pages with two-sheet intermittent printing) is used to calculate the distance using the following formula (2). TotalLj=TotalLth-TotalL Formula (2)

[0063] In other words, the total printable travel distance TotalLj is a value indicating the printable travel distance from the present time until the end of the life.

[0064] The replenishment request processing unit 501 calculates a pre-replenishment travelable distance L1j based on the travel distance (total travel distance TotalL) that the developing roller 4 has traveled since the start of use of the developing container 80 until the present. The pre-replenishment travelable distance L1j is calculated by the following formula (3) using a replenishment travel distance threshold L1th as a replenishment determination threshold. L1j=L1th-TotalL Equation (3)

[0065] That is, the pre-replenishment travelable distance L1j is a value indicating the travelable distance that can be printed from the current time (TotalL) until the replenishment request (L1th).

[0066] It should be noted that the replenishment running distance threshold L1th may be preset to a plurality of values ​​(for example, 10 km, 20 km, etc.).

[0067] In the first embodiment, the remaining toner amount threshold Tth, the total travel distance threshold TotalLth, and the replenishment travel distance threshold L1th are set in advance and stored in the memory 15. These thresholds are set in advance as values ​​that may cause an appropriate image to be unable to be formed due to a decrease in the remaining toner amount or an increase in the travel distance of the developing roller 4.

[0068] Furthermore, the replenishment request processing unit 501 and the lifespan determination processing unit 502 store in the memory 15 the calculated remaining printable toner amount Tj, total printable travel distance TotalLj, and pre-replenishment travel distance L1j.

[0069] When Tj≦0 or L1j≦0, the replenishment request processing unit 501 issues a replenishment request notification to prompt the operator to replenish, since there is a possibility that an appropriate image will not be printed. Tj≦0 is when the remaining toner amount T is equal to or less than a predetermined toner remaining amount threshold Tth (equal to or less than the remaining amount threshold). L1j≦0 is when the total travel distance TotalL (accumulated travel distance) is equal to or greater than the replenishment execution travel distance threshold L1th (equal to or greater than the first replenishment determination threshold). Furthermore, when TotalLj≦0, the life determination processing unit 502 issues a life notification to the operator, since there is a possibility that an appropriate image will not be printed even if replenishment is performed. TotalLj≦0 is when the total travel distance TotalL (accumulated travel distance) is equal to or greater than the total travel distance threshold TotalLth (equal to or greater than the life determination threshold).

[0070] In the first embodiment, the replenishment request processing unit 501 and the lifespan determination processing unit 502 display, on the operation panel 60, information to prompt the operator to perform a replenishment operation or information informing the operator that the lifespan has been reached, as a replenishment request notification or lifespan notification. The replenishment request processing unit 501 also detects that a replenishment operation has been performed based on a signal input from the operation panel 60 in response to an operation by the operator. This signal is, for example, a signal input from the operation panel 60 in response to the operator operating a button on the operation unit when the replenishment operation is completed. When the replenishment request processing unit 501 detects that a replenishment operation has been performed, it drives the developing device 8 to acquire information regarding the amount of toner remaining after the replenishment operation and the travel distance of the developing roller 4. .

[0071] <Developing device replenishment request / life notification sequence> The image forming apparatus 100 of the first embodiment issues a replenishment request notification and a lifespan notification to the operator based on the remaining toner amount T in the developing container 80, the total printable travel distance TotalLj, and the remaining travel distance L1j before replenishment. The replenishment request notification is a notification that prompts the user to perform a replenishment operation to replenish toner from the toner pack 16 to the developing device 8.

[0072] 6(A) and 6(B) are flowcharts showing a sequence for determining the replenishment timing or lifespan of the developing device 8 in Example 1. The control unit 200 detects the replenishment request timing and lifespan of the developing device 8 by performing the processes shown in the flowcharts of Fig. 6(A) and 6(B) based on the information in the memory 15 of the developing device 8, and notifies the user of the results.

[0073] First, from the start (S101), a print signal is sent to the image forming apparatus 100 (S102). Then, the image forming operation starts (S103), the developing roller travel distance L during the image forming operation is counted (S104), and the image forming operation ends (S105).

[0074] Next, the total travel distance TotalL up to the present (from S103 to S105 until just before the image forming operation is performed) is read from the memory 15 (S106).

[0075] Then, the total travel distance up to now read in S106 is added to TotalL(n-1) and the travel distance L traveled in this image forming operation is added to calculate the latest total travel distance TotalL(n) using the following equation (4) (S107). TotalL(n)=TotalL(n-1)+L Equation (4)

[0076] In the above description, an example was given of a process for updating the total distance traveled up to the present time after the image forming operation is completed, but the process may also be such that the total distance traveled is updated in real time while the image forming operation is being performed.

[0077] Next, the remaining toner amount T is measured (S108).

[0078] Then, TotalL(n) calculated in S107 is written to the memory 15 as the total travel distance TotalL updated to the latest value, and the remaining toner amount measured in S108 is written to the memory 15 as the latest remaining toner amount T (S109).

[0079] Next, the remaining toner amount threshold Tth, the total travel distance threshold TotalLth, and the replenishment travel distance threshold L1th are read from the memory 15 (S110).

[0080] First, the total printable travel distance TotalLj is calculated using the above-mentioned formula (2), and it is determined whether the relationship TotalLj>0 holds (S111).

[0081] If TotalLj>0 is not satisfied (S111: NO), the remaining printable distance is not reached, so the end of life is notified (S112), the process cartridge 9 is replaced (S118), and the process proceeds to End (S113).

[0082] If TotalLj>0 (S111: YES), the printable toner remaining amount Tj is calculated from the above formula (1), and it is determined whether the relationship Tj>0 holds (S114).

[0083] If Tj>0 is not satisfied (S114: NO), there is no remaining toner that can be used for printing, so a toner replenishment request is issued (S115). After that, a replenishment operation is carried out (S116), and the process proceeds to End (S113).

[0084] If Tj>0 (S114: YES), the pre-refueling travelable distance L1j is calculated using the above-mentioned formula (3), and it is determined whether the relationship L1j>0 holds (S117).

[0085] If L1j>0 is not satisfied (S117: NO), there is no remaining driving distance until refueling is required, so a refueling request is notified (S115). Thereafter, the refueling operation is performed (S116), and the process proceeds to End (S113).

[0086] If L1j>0 (S117: YES), there is still a remaining travelable distance before refueling, so the process proceeds to End (S113).

[0087] By executing this series of flowcharts, in the first embodiment, it is possible to notify the user of a request for a replenishment operation and the end of life of the developing device 8 before fog due to filming occurs. The end of life notification may be notified using the operation panel 60 or the like, or may be by stopping the image forming operation.

[0088] The lifespan warning threshold may be set before the total travel distance threshold TotalLth is reached. For example, if the lifespan warning threshold is set to 90% of the total travel distance threshold TotalLth, a warning that the lifespan of the developing device 8 is approaching the end of its life can be issued to the user when the remaining lifespan of the developing device 8 reaches 10%. This allows the user to prepare in advance for the replacement of the developing device 8.

[0089] Furthermore, in the first embodiment, the memory 15 is provided in the developing device 8, but this is not limitative, and a memory provided in the main body M of the image forming apparatus 100 may be used.

[0090] <Low print rate printing> Here, we will explain image formation operations with low print ratios. The print ratio can be defined as the ratio of the print area (the area of ​​the toner-covered portion of the image-formable area of ​​the recording material) to the paper area (the area of ​​the image-formable area of ​​the recording material). A typical example of low print ratio image formation is image formation in which the image is composed only of text or lines, resulting in low toner consumption. Even if the content of the image to be formed is the same, the print volume (toner consumption) is lower for smaller-sized paper than for larger-sized paper. Therefore, another definition of print ratio is the ratio of the print volume to the print volume when a full black image (solid black image) is formed on a sheet of paper of a specified size (e.g., letter size). Under this definition, for the same image content, the smaller the paper size, the lower the print ratio of the image formed.

[0091] Deterioration of toner is one of the causes of image defects such as fogging, and one of the factors of toner deterioration is the flow of toner inside the developing container during image formation. The toner inside the developing container 80 is repeatedly rubbed by the supply roller 5 and the developing blade 6 during image formation, causing external additives to separate from or be embedded in the toner matrix, and deformation of the toner matrix itself, leading to deterioration. The toner used for development during image formation is only a portion of the toner inside the developing container 80, and most toner remains in the developing container 80 without being used for development. This residual toner becomes more noticeable when image formation continues at a low print rate. The lower the print rate of image formation, the more toner in the developing container 80 remains in the developing container 80 without being consumed, and many image formations are formed before toner is replenished into the developing container 80. The toner deterioration progresses as it remains in the developer container 80 without being used for development each time an image is formed. Therefore, the lower the print rate of image formation, the more the toner deterioration in the developer container 80 accelerates before the toner in the developer container 80 is consumed to a predetermined amount that prompts the user to replenish toner, and image defects such as fogging are more likely to occur before toner replenishment is performed. In other words, when an image mainly consists of text or lines, or when the size of the recording material is small, image defects are more likely to occur due to toner deterioration in the developer container 80.

[0092] In the first embodiment, even when image formation operations with a low print rate are repeated, a toner replenishment request is notified and toner is replenished when L1j reaches 0 before the amount of toner in the developer container 80 reaches the remaining toner threshold Tth. Therefore, fresh toner can be replenished before the running distance of the developing roller 4 becomes excessively long when the amount of toner consumption is low, which would cause toner deterioration or wear of the developing roller 4. This makes it possible to prevent image defects such as fogging caused by toner deterioration or wear of the developing roller 4.

[0093] <Evaluation Experiment of Example 1> Images were formed on 25,000 sheets of recording material using experimental image data. Three types of horizontal line patterns with image printing rates of 4%, 2%, and 1.75% were used as experimental images. The replenishment running distance threshold L1th was set to 10 km, and the total running distance threshold TotalLth was set to 25 km. Figure 7 shows the results of these tests. Each case will be explained below.

[0094] Case 1 (Reference Example 1): High print rate print (image print rate 4%) Because the print rate was high, toner consumption progressed, and the time when the remaining printable toner amount Tj = 0 occurred was when the total travel distance TotalL = 5 km. Because the toner was consumed before the toner deteriorated or the developing roller began to wear out, no fogging occurred and the time to replenish the toner arrived. Furthermore, by carrying out the replenishment operation, the deteriorated toner in the developing device was replaced with new toner. This mitigated the effects of toner deterioration and wear of the developing roller, and the image forming device could continue to be used up to the total travel distance threshold TotalLth = 25 km without fogging occurring.

[0095] Case 2 (Reference Example 2): Low print rate print 1 (image print rate 2%) Because the print rate is half that of Case 1, the timing when the remaining printable toner amount Tj = 0 occurs is when the total travel distance TotalL = 10 km, which is twice as long as in Case 1. Compared to Case 1, toner consumption is lower, so toner degradation and wear of the developing roller progress, but fogging does not occur and the time for toner replenishment arrives. Also, as in Case 1, the replenishment operation replaces the deteriorated toner in the developing device with new toner. This mitigates the effects of toner degradation and wear of the developing roller, and the image forming device can continue to be used up to the total travel distance threshold TotalLth = 25 km without fogging occurring.

[0096] Case 3 (comparison example): Low print rate print 2 (image print rate 1.75%) Because the print rate is slightly lower than in Case 2, the timing when the remaining printable toner amount Tj=0 occurs when the total travel distance TotalL=11.5 km. Because the amount of toner consumed is even less than in Case 2, the toner deteriorates and the developing roller wears out, and fogging occurs when the total travel distance TotalL=11 km, just before the timing of Tj=0.

[0097] Case 4 (Example 1): Low print rate print 2 (image print rate 1.75%) + L1j In a case similar to Case 3, by setting the replenishment running distance threshold L1th=10 km, the replenishment operation was performed just before the total running distance at which fogging occurs was reached. By replacing the deteriorated toner in the developing device 8 with new toner, the deterioration of the toner and the development The influence of roller wear was alleviated, and the image forming apparatus 100 could be used without fog occurring up to the total travel distance threshold TotalLth=25 km.

[0098] It was found that in the method of replenishing toner all at once as in Example 1, the supply of fresh developer by replenishment significantly improved the filming state of the developing roller 4. By carrying out the replenishment operation at the appropriate time as in Example 1, it became possible to continue printing without the occurrence of fogging.

[0099] As described above, by setting the pre-replenishment travelable distance L1j, replenishment can be performed before fogging occurs, allowing the image forming apparatus 100 to be used continuously without fogging occurring.

[0100] In the first embodiment, only one value (10 km) is set as the refueling mileage threshold L1th, but multiple thresholds may be set. For example, the first threshold L1th1 may be set to 10 km and the second threshold L1th2 may be set to 19 km, and refueling may be performed based on the first threshold L1th1 (10 km) in S117. Thereafter, the threshold used in S117 may be changed to the second threshold L1th2 (19 km), and processing may continue according to the flowcharts of FIGS. 6(A) and 6(B).

[0101] Example 2 In the second embodiment, explanation of the parts that overlap with the first embodiment will be omitted, and only the parts that are unique to the second embodiment will be explained. In the second embodiment, in addition to the first embodiment, a running distance between replenishments RefillL, a toner usage amount T1, and a possible running distance between replenishments L2j before replenishment are set. The running distance between replenishments RefillL (the running distance between replenishments) is the sum of the running distance (travel distance) of a predetermined section of the surface of the developing roller 4 after toner replenishment. The toner usage amount T1 is the amount of toner used from the initial time or immediately after replenishment. The possible running distance between replenishments L2j before replenishment is the running distance that can be printed from the current time until a replenishment request is made. This makes it possible to notify an early replenishment request in cases where the amount of toner usage is low and the running distance between replenishments is long. This makes it possible to suppress toner deterioration in the developing device 8 and wear of the developing roller 4, and to prevent fogging.

[0102] <Control configuration> 8 shows a block diagram used in the second embodiment. Explanation of parts that overlap with the first embodiment will be omitted. In the second embodiment, the developing roller travel distance detection unit 400 has an inter-replenishment travel distance calculation unit 403 in addition to a developing roller travel distance measurement unit 401 and a total travel distance calculation unit 402. The inter-replenishment travel distance calculation unit 403 calculates the travel distance of the developing roller 4 from the start of use or from immediately after a replenishment operation is performed until the next replenishment operation is performed.

[0103] 9(A) and 9(B) are flowcharts showing a sequence for determining the replenishment timing or lifespan of the developing device 8 in Example 2. The control unit 200 detects the replenishment request timing and lifespan of the developing device 8 by performing the processes shown in the flowcharts of Fig. 9(A) and 9(B) based on the information in the memory 15 of the developing device 8, and notifies the user of the results.

[0104] First, from the start (S201), a print signal is sent to the image forming apparatus 100 (S202). Then, the image forming operation starts (S203), the developing roller travel distance L during the image forming operation is counted (S204), and the image forming operation ends (S205).

[0105] Next, the total travel distance TotalL up to the present (from S203 to S205 until just before the image forming operation is performed) and the travel distance between replenishments RefillL up to the present are read from the memory 15 (S2 06).

[0106] The total travel distance up to now read in S206 is set as TotalL(n-1), and the travel distance L in the current image forming operation is added to this to calculate the latest total travel distance TotalL(n) (S207). The latest total travel distance TotalL(n) is calculated using the formula (4) used in the first embodiment.

[0107] The current inter-replenishment travel distance read in S206 is set as RefillL(n-1), and the travel distance L in the current image forming operation is added to this to calculate the latest inter-replenishment travel distance RefillL(n) (S208). The latest inter-replenishment travel distance RefillL(n) is calculated using the following equation (5). RifillL(n)=RifillL(n-1)+L Equation (5)

[0108] Next, the remaining toner amount T is measured (S209).

[0109] Then, TotalL(n) calculated in S207 is written to memory 15 as the total travel distance TotalL updated to the latest value. Also, RefillL(n) calculated in S208 is written to memory 15 as the travel distance between replenishments RefillL updated to the latest value. Also, the remaining toner amount measured in S209 is written to memory 15 as the latest remaining toner amount T (S210).

[0110] Next, the remaining toner amount threshold Tth, the toner usage amount threshold T1th, the initial / immediately after replenishment remaining toner amount T0, the total travel distance threshold TotalLth, and the travel distance between replenishment executions threshold L2th are read from the memory 15 (S211).

[0111] If a replenishment operation has never been performed, the initial / immediately after replenishment remaining toner amount T0 stores the amount of toner filled when the product was new. After a replenishment operation has been performed, the amount of toner remaining immediately after the replenishment operation is actually measured, and the initial / immediately after replenishment remaining toner amount T0 is updated with this measured value.

[0112] First, the total printable travel distance TotalLj is calculated from the equation (2) explained in the first embodiment, and it is determined whether the relationship TotalLj>0 holds (S212).

[0113] If TotalLj>0 is not satisfied (S212: NO), there is no remaining printable distance, so the end of life is notified (S213), the process cartridge 9 is replaced (S222), and the process proceeds to End (S214).

[0114] If TotalLj>0 (S212: YES), the printable toner remaining amount Tj is calculated from the formula (1) explained in the first embodiment, and it is determined whether the relationship Tj>0 holds (S215).

[0115] If Tj > 0 is not true (S215: NO), there is no toner remaining that can be used for printing, and a toner replenishment request is issued (S216). Then, a replenishment operation is performed (S217), and the amount of toner remaining in the developer container immediately after replenishment, T, is measured (S218). Then, the travel distance between replenishments, RefillL, in memory 15, is updated to 0, and the initial / immediately after replenishment toner remaining amount, T0, is updated to T (S219), and the process proceeds to End (S214).

[0116] If Tj>0 (S215: YES), the toner usage amount T1 from the beginning or immediately after replenishment is calculated using the following formula (6), and is compared with the toner usage amount threshold T1th to determine the toner usage amount. It is determined whether the amount is small (S220). T1=T0-T formula (6)

[0117] If T1>T1th (S220: YES), that is, if the amount of toner T1 used from the beginning or immediately after replenishment is large, it is determined that toner deterioration or developing roller filming will not occur, and the process proceeds to End (S214).

[0118] If T1>T1th is not true (S220: NO), that is, if the amount of toner used T1 from the beginning or immediately after replenishment is small, the remaining travel distance L2j between replenishment and before replenishment is calculated using the following equation (7), and it is determined whether there is a remaining travel distance sufficient for printing (S221). L2j=L2th-RifillL Equation (7)

[0119] That is, the pre-replenishment travel distance L2j is a value indicating the pre-replenishment travel distance that can be printed from the current time (RefillL) to the replenishment request (L2th).

[0120] If L2j > 0 is not true (S221: NO), new toner needs to be replenished due to toner degradation and developing roller filming, so a toner replenishment request is issued (S216). Then, a replenishment operation is performed (S217), and the amount of toner remaining in the developing container immediately after replenishment, T, is measured (S218). Then, the travel distance between replenishments, RefillL, in memory 15 is updated to 0, and the initial / immediately after replenishment toner remaining amount, T0, is updated to T (S219), and the process proceeds to End (S214).

[0121] If L2j>0 (S221: YES), the remaining toner amount is sufficient and the running distance between replenishments is not too far, so it is determined that toner deterioration or developing roller filming will not occur, and the process proceeds to End (S214).

[0122] By executing this series of flowcharts, a replenishment request notification is issued when the remaining toner amount T becomes equal to or less than a predetermined toner remaining amount threshold Tth (below the remaining amount threshold). Furthermore, a replenishment request notification is issued when the amount of toner used since the previous replenishment T1 becomes equal to or less than a predetermined threshold T1th and the travel distance between replenishments RefillL (travel distance between replenishments) becomes equal to or greater than the travel distance between replenishments threshold L2th (above the second replenishment determination threshold). In the second embodiment, a replenishment operation request and the end of life of the developing device 8 can be notified to the user before fog due to filming occurs. The end of life notification may be notified via the operation panel 60 or the like, or by stopping the image forming operation.

[0123] In addition, in the second embodiment, only one value is used as the toner usage threshold T1th to determine the toner usage T1 from the beginning or immediately after replenishment. However, multiple toner usage thresholds may be used. Furthermore, the inter-replenishment travel distance RefillL may be determined using multiple inter-replenishment travel distance thresholds L2th based on the determination results based on the multiple toner usage thresholds T1th. This allows for life setting that corresponds to various print rate patterns.

[0124] In the second embodiment, the timing of replenishment is changed (S221) depending on the determination of the toner usage amount T1 (S220). However, it is also possible to calculate the print rate and the amount of toner consumed per unit travel distance, and set a different inter-replenishment travel distance threshold L2th for each print rate zone or for each amount of toner consumed per unit travel distance. For example, the threshold can be set to 4 km when the print rate is 0 to 0.5%, and 6 km when the print rate is 0.6 to 1%.

[0125] In the second embodiment, the determination of whether to replenish (S221) is performed based on the pre-replenishment running distance L2j is performed in accordance with the result of the determination of the toner usage amount T1 (S220). However, the determination of whether to replenish is performed may also be performed in accordance with the result of the determination of the toner usage amount in printing with a lower print rate than a predetermined print rate (low print rate toner usage amount). For example, by performing the determination of S221 when the low print rate toner usage amount exceeds the low print rate toner usage threshold, early replenishment can be performed for operators who mainly print with low print rates, thereby suppressing fogging.

[0126] If no refueling has been performed, the distance traveled between refuelings, RefillL, is equal to the total distance traveled, TotalL.

[0127] <Evaluation Experiment of Example 2> Images were formed on 30,000 sheets of recording material using experimental image data. Three types of horizontal line patterns with image printing rates of 4%, 2%, and 1.5% were used as experimental images. The toner usage threshold T1th was set to 30 g, the running distance threshold between replenishment L2th was set to 7 km, and the total running distance threshold TotalLth was set to 30 km. Figure 10 shows the results of these tests. Each case will be explained below.

[0128] Case 1 (Reference Example 1): High print rate print (image print rate 4%) Because the print coverage was high, toner consumption progressed, and the remaining printable toner amount Tj = 0 occurred when the total travel distance TotalL = 5 km. Because the toner was consumed before the toner deteriorated or the developing roller began to wear out, no fogging occurred and the time for toner replenishment arrived. In addition, by performing replenishment operations every 5 km, such as when the total travel distance TotalL = 5 km, 10 km, etc., the deteriorated toner in the developing device was replaced with new toner. This mitigated the effects of toner deterioration and wear on the developing roller, and the image forming device could continue to be used up to the total travel distance threshold TotalLth = 30 km without fogging occurring.

[0129] Case 2 (Reference Example 2): Low print rate print 1 (image print rate 2%) Because the print rate is half that of Case 1, the timing when the remaining printable toner amount Tj = 0 occurs is when the total travel distance TotalL = 10 km, twice as long as in Case 1. Compared to Case 1, toner consumption is lower, so toner degradation and wear of the developing roller progress, but fogging does not occur and the time for toner replenishment arrives. In addition, by performing a replenishment operation every 10 km, such as when the total travel distance TotalL = 10 km, 20 km, etc., the degraded toner in the developing device is replaced with new toner. This mitigates the effects of toner degradation and wear of the developing roller, and the image forming device can continue to be used up to the total travel distance threshold TotalLth = 30 km without fogging occurring.

[0130] Case 3 (comparison example): Low print rate print 2 (image print rate 1.5%) Because the print rate is lower than in Case 2, the timing when the remaining printable toner amount Tj=0 occurs when the total travel distance TotalL=13.5 km. Because the amount of toner consumed is even less than in Case 2, the toner deteriorates and the developing roller wears out, and fogging occurs when the total travel distance TotalL=8.5 km, just before the timing of Tj=0.

[0131] Case 4 (Example 2): Low print rate print 2 (image print rate 1.5%) + T1, L2j set In the same case as Case 3, the toner usage threshold T1th is set to 30 g, and the running distance between replenishments threshold L2th is set to 7 km. As a result, the remaining toner amount T is sufficient for printing (the toner usage amount T1 is small), but the running distance between replenishments RefillL is long. Even in such a usage situation where low print rate printing is the main focus, in the case of Example 2, the deteriorated toner in the developing device 8 is replaced with new toner by performing a replenishment operation every time the travel distance between replenishments, RefillL, reaches 7 km (L2th). This reduces the effects of toner deterioration and wear of the developing roller, and the image forming apparatus 100 can be used continuously up to the total travel distance threshold, TotalLth, of 30 km, without the occurrence of fogging.

[0132] As described above, by setting the toner usage amount T1 and the travelable distance between replenishment and pre-replenishment L2j, replenishment can be performed before fogging occurs, allowing the image forming apparatus 100 to continue to be used without fogging occurring.

[0133] In the second embodiment, a single value (e.g., 30 g) is used as the toner usage threshold T1th. However, multiple values ​​may be set, and a different inter-replenishment travel distance threshold L2th may be set for each toner usage threshold. For example, the second toner usage threshold T1th2 may be set to 15 g, and the second inter-replenishment travel distance threshold L2th2 may be set to 4 km. This allows users with even lower print rates to perform a replenishment operation before toner degradation or development roller wear progresses, enabling them to continue using the image forming apparatus without generating fogging.

[0134] In the second embodiment, a single value (e.g., 7 km) is set as the inter-replenishment travel distance threshold L2th, but multiple values ​​may be set. For example, depending on the number of replenishments, the threshold used to determine whether a second replenishment is required may be set to 6.8 km, and the threshold used to determine whether a third replenishment is required may be set to 6.7 km, and the processing may continue after one replenishment according to the flowcharts of Figures 9(A) and 9(B).

[0135] Example 3 The third embodiment is characterized in that, in addition to the parameters described in the first embodiment, a correction coefficient for correcting the travel distance of the developing roller 4 is used to calculate the corrected total travel distance and the corrected travel distance between replenishments. In the third embodiment, explanations of parts that overlap with the first embodiment will be omitted, and only parts unique to the third embodiment will be explained.

[0136] <Control configuration> FIG. 11 shows a block diagram used in the third embodiment. Explanation of parts that overlap with the first and second embodiments will be omitted. In the third embodiment, the developing roller travel distance detection unit 400 has a corrected inter-replenishment travel distance calculation unit 404. The corrected inter-replenishment travel distance calculation unit 404 corrects and integrates the inter-replenishment travel distance using a correction coefficient. The correction coefficient will be described later.

[0137] In the third embodiment, in addition to the parameters described in the first embodiment, a correction coefficient for correcting the travel distance of the developing roller 4 is used to calculate the corrected total travel distance and the corrected travel distance between replenishments. As a result, in cases where the amount of toner used is small and the travel distance since replenishment is long, a large correction is made to the travel distance, making it possible to notify an early replenishment request. This makes it possible to suppress toner deterioration in the developing device 8 and wear of the developing roller 4, and to prevent fogging.

[0138] 12(A) and 12(B) are flowcharts showing a sequence for determining the replenishment timing or lifespan of developing device 8 in Example 3. Control unit 200 performs the processes shown in the flowcharts of Fig. 12(A) and 12(B) based on the information in memory 15 of developing device 8, thereby detecting the replenishment request timing and lifespan of developing device 8 and notifying the user of the results.

[0139] First, from the start (S301), a print signal is sent to the image forming apparatus 100 (S302). Then, the image forming operation starts (S303), the travel distance L during the image forming operation is counted (S304), and the image forming operation ends (S305).

[0140] Next, the total travel distance TotalL up to now (from S303 to just before the image forming operation in S305 is performed), the corrected total travel distance TotalLt up to now, and the corrected inter-replenishment travel distance Lt up to now are read from the memory 15 (S306).

[0141] The total travel distance up to now read in S306 is set as TotalL(n-1), and the travel distance L in the current image forming operation is added to this to calculate the latest total travel distance Total(n) (S307). The latest total travel distance TotalL(n) is calculated using the formula (4) used in the first embodiment.

[0142] Next, the remaining toner amount T is measured (S308).

[0143] Then, the correction coefficient k corresponding to the remaining toner amount T is determined by referring to the correction table (FIG. 13) stored in advance in the memory 15 (S309).

[0144] Next, the corrected travel distance Lu is calculated using the selected correction coefficient k according to the following equation (8) (S310). Lu=L×k Equation (8)

[0145] The corrected total mileage up to now read in S306 is defined as TotalLt(n-1), and the corrected mileage Lu calculated by equation (8) is added to this to calculate the latest corrected total mileage TotalLt(n) (S311). The latest corrected total mileage TotalLt(n) is calculated by the following equation (9). TotalLt(n)=TotalLt(n-1)+Lu Equation (9)

[0146] The corrected travel distance Lu is a corrected travel distance obtained by correcting the travel distance of a predetermined section of the surface of the developing roller 4 based on remaining amount information, which is information related to the amount of toner contained in the toner storage chamber 8a. The corrected total travel distance TotalLt is a corrected cumulative travel distance obtained by integrating the corrected travel distances from the beginning of use of the developing device 8.

[0147] Next, the corrected inter-refueling mileage up to now read in S306 is set as Lt(n-1), and the corrected mileage Lu calculated by equation (8) is added to this to calculate the latest corrected inter-refueling mileage Lt(n) (S312). The latest corrected inter-refueling mileage Lt(n) is calculated by the following equation (10). Lt(n)=Lt(n-1)+Lu Equation (10)

[0148] The corrected inter-replenishment travel distance Lt is a corrected inter-replenishment travel distance obtained by accumulating the corrected travel distance since the previous toner replenishment.

[0149] Then, TotalL(n) calculated in S307 is written as the latest total mileage TotalL in the memory 15. Also, TotalLt(n) calculated in S311 is written as the latest total mileage TotalL. The correct total travel distance TotalLt is written to the memory 15. Also, Lt(n) calculated in S312 is written to the memory 15 as the latest corrected inter-replenishment travel distance Lt. Also, the remaining toner amount measured in S308 is written to the memory 15 as the latest remaining toner amount T (S313).

[0150] Next, the remaining toner amount threshold Tth, the total travel distance threshold TotalLth, and the inter-replenishment travel distance threshold L3th are read from the memory 15 (S314).

[0151] First, the total printable travel distance TotalLj is calculated from the equation (2) explained in the first embodiment, and it is determined whether the relationship TotalLj>0 holds (S315).

[0152] If TotalLj>0 is not satisfied (S315: NO), there is no remaining printable distance, so the end of life is notified (S316), the process cartridge 9 is replaced (S324), and the process proceeds to End (S317).

[0153] If TotalLj>0 (S315: YES), the corrected total printable travel distance TotalL1j is calculated using the following formula (11), and it is determined whether there is any remaining amount (S318). TotalL1j=TotalLth-TotalLt Equation (11)

[0154] That is, the corrected total printable travel distance TotalL1j is a value indicating the corrected travel distance between replenishments that can be printed from the current time (TotalLt) until the end of the life.

[0155] If TotalL1j>0 is not satisfied (S318: NO), the remaining printable distance is not reached, so the end of life is notified (S316) and the process proceeds to End (S317).

[0156] If TotalL1j>0 (S318: YES), there is still a printable distance remaining, so the remaining printable toner amount Tj is calculated using equation (1) described in the first embodiment, and it is determined whether the relationship Tj>0 holds (S319).

[0157] If Tj>0 is not satisfied (S319: NO), there is no remaining toner suitable for printing, and a toner replenishment request is issued (S320). Then, a replenishment operation is carried out (S321), the corrected inter-replenishment travel distance Lt in memory 15 is updated to 0 (S322), and the process proceeds to End (S317).

[0158] If Tj>0 (S319: YES), the pre-replenishment running distance L3j is calculated using the following equation (12), and it is determined whether there is any remaining amount (S323). L3j=L3th-Lt Equation (12)

[0159] If L3j>0 is not satisfied (S323: NO), a toner replenishment request is issued (S320), and a replenishment operation is then performed (S321), the corrected inter-replenishment travel distance Lt in the memory 15 is updated to 0 (S322), and the process proceeds to End (S317).

[0160] If L3j>0 (S323: YES), there is still a driving distance remaining before refueling, so the process proceeds to End (S317).

[0161] By executing this series of flowcharts, the corrected total mileage TotalLt( When the corrected cumulative travel distance (Lt) becomes equal to or greater than the total travel distance threshold TotalLth (equal to or greater than the life determination threshold), a notification is issued that the developing device 8 has reached the end of its life. Also, when the remaining toner amount T becomes equal to or less than the remaining toner amount threshold Tth, a replenishment request notification is issued. Also, when the corrected inter-replenishment travel distance Lt (corrected inter-replenishment travel distance) becomes equal to or greater than the inter-replenishment travel distance threshold L3th (equal to or greater than the third replenishment determination threshold), a replenishment request notification is issued.

[0162] In the third embodiment, the need for replenishment can be determined based on a corrected travel distance, which is the actual travel distance corrected according to the remaining toner amount. In the example shown in FIG. 13, the greater the remaining toner amount, the larger the correction coefficient, resulting in a longer calculated corrected travel distance. That is, when correcting the travel distance based on the remaining toner amount information, the greater the remaining toner amount, the greater the corrected travel distance. Therefore, in a usage situation where there is a lot of low-coverage printing and little toner usage, the cumulative value of the corrected travel distance is likely to increase, resulting in earlier replenishment. This allows the user to be notified of a replenishment operation request and the end of life of the developing device 8 before filming occurs. The end-of-life notification method may be a method of notifying the user that the end of life has been reached via the operation panel 60, or a method of stopping image formation operations.

[0163] In the third embodiment, the determination of whether there is a remaining driving distance until refueling is performed is performed using the inter-refueling driving distance threshold L3th. However, the determination may also be performed using L1th used in the first embodiment or L2th used in the second embodiment.

[0164] Although the third embodiment describes an example in which the correction coefficient is determined based only on the remaining toner amount, the correction coefficient may be determined based on other conditions. For example, the correction coefficient may be determined based on the travel distance between replenishments at the time of replenishment or the remaining toner amount at the time of the previous replenishment, in addition to the remaining toner amount. In the example shown in FIG. 14, the correction coefficient increases as the travel distance between replenishments increases, so the corrected travel distance increases as the travel distance increases. That is, the corrected travel distance is further corrected to a larger value as the travel distance between replenishments, which is the cumulative total of the travel distance since the previous toner replenishment, increases. Therefore, in usage situations where there are many low-coverage prints and the travel distance is likely to increase, the cumulative value of the corrected travel distance is more likely to increase, and replenishment will be performed earlier. Furthermore, the greater the remaining toner amount at the time of the previous replenishment, the larger the correction coefficient. That is, the corrected travel distance is further corrected to a larger value as the remaining toner amount at the time of the previous replenishment increases. Therefore, in situations where there are many low-coverage prints and replenishment is performed when toner usage is low, the cumulative value of the corrected travel distance is more likely to increase, and replenishment will be performed earlier. In this way, it is possible to use an appropriate correction coefficient depending on the deterioration of toner in the developing device 8 and the degree of wear of the developing roller 4 during the replenishment operation. Note that while the example in FIG. 14 shows an example in which the correction coefficient is changed in two stages depending on the running distance between replenishments, the correction coefficient may be changed more finely depending on the running distance between replenishments. For example, the correction coefficient is set to be larger as the running distance between replenishments increases. This makes it possible to issue an earlier replenishment request notification in usage situations where there is a lot of low-coverage printing and the running distance is likely to increase.

[0165] <Evaluation Experiment of Example 3> Images were formed on 30,000 sheets of recording material using experimental image data. Three types of horizontal line patterns with image printing rates of 4%, 2%, and 1% were used as experimental images. The correction coefficients shown in Figure 13 were set. The travel distance threshold between replenishment runs, L3th, was set to 10 km, and the total travel distance threshold, TotalLth, was set to 30 km. Figure 15 shows the results of these tests. Each case will be explained below.

[0166] Case 1 (Reference Example 1): High print rate print (image print rate 4%) Because the print rate is high, toner consumption progresses, and the timing when the remaining printable toner amount Tj becomes 0 occurs when the total distance traveled TotalL = 5 km. At this point, the corrected running distance between replenishments, Lt, reached 10 km, reaching the preset running distance threshold between replenishments, L3th, at 10 km. In this case, the toner was consumed before the toner deteriorated or the developing roller began to wear out, so there was no fogging and the time for toner replenishment arrived. Furthermore, replenishment operations were performed every 5 km, with the total running distance TotalL = 5 km, 10 km, etc. As a result, the deteriorated toner in the developing device was replaced with new toner, mitigating the effects of toner deterioration and developing roller wear. The image forming device could then be used up to the total running distance threshold TotalLth = 30 km without fogging. By continuing to replenish every 5 km, the lifespan warning was issued when the total running distance threshold TotalLth = 30 km.

[0167] Case 2 (Reference Example 2): Low print rate print 1 (image print rate 2%) Because the print rate was half that of Case 1, the timing when the printable toner remaining amount Tj = 0 occurred was when the total travel distance TotalL = 10 km, twice that of Case 1. Furthermore, after actually traveling 10 km, the corrected travel distance between replenishments Lt = 10 km, reaching the preset travel distance threshold between replenishments L3th = 10 km. Compared to Case 1, toner consumption was lower, so toner degradation and wear of the developing roller progressed, but fogging did not occur, and the time for toner replenishment arrived. Furthermore, replenishment operations were performed every 10 km, for total travel distances TotalL = 10 km, 20 km, etc. By replacing the deteriorated toner in the developing device with new toner, the effects of toner degradation and wear of the developing roller were mitigated, and the image forming device could continue to be used without fogging until the total travel distance threshold TotalLth = 30 km. After that, replenishment was repeated every 10 km, and a lifespan notification was issued when the total travel distance threshold TotalLth = 30 km.

[0168] Case 3 (Comparative Example 1): Low print rate print 2 (image print rate 1%) Because the print rate is lower than in Case 2, the timing when the remaining printable toner amount Tj = 0 occurred when the total travel distance TotalL = 20 km. Because the toner consumption amount was even lower than in Case 2, the toner degradation and wear of the developing roller progressed, and fogging occurred when the total travel distance TotalL = 7 km, just before the timing when Tj = 0 occurred. Because fogging occurred, the evaluation was discontinued before the total travel distance threshold TotalLth = 30 km was reached.

[0169] Case 4 (Comparative Example 2): Low print rate print 2 (image print rate 1%) + L3j In a case similar to Case 3, the corrected inter-replenishment mileage Lt was calculated using a preset correction coefficient. The uncorrected inter-replenishment mileage Lt reached the inter-replenishment mileage threshold L3th = 10 km when the vehicle had traveled 6 km. As a result, a replenishment operation was performed at 6 km, before the 7 km mark where fogging occurred. Replenishment operations were performed every 6 km thereafter, but after the third replenishment at 18 km, fogging occurred at 19 km. In other words, most of the toner from the third replenishment was unusable, and fogging occurred at 19 km. This indicates that the toner in the developing device had deteriorated and the developing roller had worn out just before the replenishment. Even adding new toner during the replenishment operation could not mitigate these effects, making further use difficult. Due to the occurrence of fogging at 19 km, the evaluation was discontinued before the total mileage threshold TotalLth = 30 km was reached.

[0170] Case 5 (Example 3): Low print rate print 2 (image print rate 1%) + L3j, TotalLt In the third embodiment, when the uncorrected total travel distance TotalL=18 km when the third replenishment is performed, the corrected total travel distance TotalLt reaches the total travel distance threshold TotalLth=30 km, and the end of life notification is performed at this timing. This allows the user to take measures such as replacing the developing device 8 and continue using the image forming apparatus 100 without causing fogging or wasting the replenished toner.

[0171] As described above, by setting the correction coefficient for correcting the developing travel distance and the corrected total travel distance, replenishment is performed before fogging occurs. This makes it possible to provide an image forming apparatus that suppresses the occurrence of fogging and issues a lifespan warning to prevent unnecessary toner replenishment.

[0172] Example 4 In addition to the parameters described in the third embodiment, the fourth embodiment is characterized in that it sets the amount of toner replenished last time from the toner pack 16, ΔT, and uses a correction coefficient k corresponding to the amount of toner replenished ΔT. In the fourth embodiment, explanations of parts that overlap with the first and third embodiments will be omitted, and only parts unique to the fourth embodiment will be explained.

[0173] In the fourth embodiment, even when the amount of replenished toner is small or large, it is possible to notify a replenishment request at an appropriate timing by setting a correction coefficient k that takes into account the progress of toner deterioration and wear of the developing roller 4. This makes it possible to suppress toner deterioration in the developing device 8 and wear of the developing roller 4, and to prevent the occurrence of fogging.

[0174] 16(A) and 16(B) are flowcharts showing a sequence for determining the replenishment timing or lifespan of developing device 8 in Example 4. Control unit 200 performs the processes shown in the flowcharts of Fig. 16(A) and 16(B) based on the information in memory 15 of developing device 8, thereby detecting the replenishment request timing and lifespan of developing device 8 and notifying the user of the results.

[0175] The flowcharts of Figures 16(A) and 16(B) are generally the same as the flowcharts of Figures 12(A) and 12(B) of the third embodiment. That is, S401 to S405, S407 to S408, S410 to S421, and S423 to S424 are the same as S301 to S305, S307 to S308, S310 to S321, and S323 to S324 in the flowcharts of Figures 12(A) and 12(B). S406, S409, and S422 are different from S306, S309, and S322, and S4211, which was not included in the flowcharts of Figures 12(A) and 12(B), has been added. The differences from Figures 12(A) and 12(B) will be described below.

[0176] At the timing of replenishment in S421, the toner replenishment amount ΔT is measured (S4211), and the corrected inter-replenishment travel distance Lt=0 and information on the toner replenishment amount ΔT are written to memory 15 (S422). The toner replenishment amount ΔT from the previous replenishment written here is read from memory 15 (S406), and based on the read toner replenishment amount ΔT, a correction coefficient k is determined by referring to the correction table (S409).

[0177] An example of the correction table is shown in FIG. 17. A correction coefficient k corresponding to the remaining toner amount T is determined for each of the cases where the toner supply amount ΔT is 80 g and 40 g. In this way, it is possible to select a correction coefficient corresponding to the previous toner supply amount. Different toner supply amounts result in different progressions of toner deterioration and wear of the developing roller 4. Specifically, when the toner supply amount is small, toner deterioration in the developing device 8 and wear of the developing roller 4 progress. In the example of FIG. 17, the smaller the toner supply amount, the larger the correction coefficient, and therefore the larger the corrected travel distance Lt. In other words, the smaller the amount of toner supplied the previous time, the larger the corrected travel distance Lt. This allows for earlier determination of whether toner needs to be supplied or if the toner has reached its end of life, thereby preventing fogging and unnecessary toner supply.

[0178] In the fourth embodiment, the toner supply amount ΔT is obtained by actual measurement. For example, if the memory of the toner pack stores information indicating the amount of toner filled in the toner pack, the device main body M or the developing device 8 may be provided with a means for communicating with the memory of the toner pack. Then, by receiving information from the memory of the toner pack at the timing of the replenishment operation, the amount of toner replenishment may be obtained and written to the memory 15.

[0179] Furthermore, if product information such as the model number of the toner pack is stored in a memory provided in the toner pack, a means for communicating with the memory of the toner pack is provided in the device main body M or the developing device 8. Furthermore, a table showing the correspondence between the product information of the toner pack and the amount of toner filled therein is stored in memory 15. Then, during a replenishment operation, the product information may be received from the memory of the toner pack, the amount of toner corresponding to the product information may be obtained, and this may be written to memory 15.

[0180] Furthermore, in the fourth embodiment, an example was shown in which the correction coefficient was determined based on the toner supply amount ΔT, but as shown in FIG. 18, the replenishment execution travel distance threshold L3th may also be set according to the toner supply amount ΔT. In this case, as in the third embodiment, the correction coefficient may also be determined based only on the remaining toner amount T. In the example of FIG. 18, the smaller the toner supply amount ΔT when the previous toner replenishment was performed, the smaller the replenishment execution travel distance threshold L3th (third replenishment determination threshold). Therefore, in a situation where the toner supply amount is low and toner deterioration in the developing device 8 or wear of the developing roller 4 is likely to progress, the replenishment determination will be made earlier.

[0181] Example 5 The fifth embodiment is characterized by using a different correction coefficient for each number of replenishments performed in addition to the parameters described in the third embodiment. In the fifth embodiment, explanations of the parts that overlap with the first and third embodiments will be omitted, and only the parts specific to the fifth embodiment will be explained.

[0182] In the fifth embodiment, it is possible to notify a replenishment request at an appropriate timing by setting a correction coefficient k that takes into consideration the deterioration of toner in the developing device 8 due to an increase in the number of replenishments and the progress of wear of the developing roller 4. This makes it possible to suppress the deterioration of toner in the developing device 8 and wear of the developing roller 4, and to prevent the occurrence of fogging.

[0183] 19(A) and 19(B) are flowcharts showing a sequence for determining the replenishment timing or lifespan of developing device 8 in Example 5. Control unit 200 performs the processes shown in the flowcharts of Fig. 19(A) and 19(B) based on the information in memory 15 of developing device 8, thereby detecting the replenishment request timing and lifespan of developing device 8 and notifying the user of the results.

[0184] The flowcharts in Figures 19(A) and 19(B) are generally the same as the flowcharts in Figures 12(A) and 12(B) of the third embodiment. That is, S501 to S505, S507 to S508, S510 to S521, and S523 to S524 are the same as S301 to S305, S307 to S308, S310 to S321, and S323 to S324 in the flowcharts in Figures 12(A) and 12(B). S506, S509, and S522 are different from S306, S309, and S322. Below, the differences from Figures 12(A) and 12(B) will be explained.

[0185] After the replenishment operation is performed (S521), the corrected inter-replenishment traveling distance Lt=0 and the latest number of replenishments N are written to memory 15 (S522). Here, the latest number of replenishments is calculated as N(n)=N(n-1)+1, where N(n-1) is the number of replenishments up to the previous replenishment read in S506, and N(n) is the latest number of replenishments. N(n) calculated in this way is written to memory 15 as the latest number of replenishments N (S522). The number of replenishments N written here is read from memory 15 (S506), and a correction coefficient k is determined by referring to the correction table based on the read number of replenishments N (S509).

[0186] An example of the correction table is shown in FIG. 20. A correction coefficient k corresponding to the remaining toner amount T is set for each of the cases where the number of replenishments N is 0, 1, and 2. In this way, it is possible to select a correction coefficient according to the number of toner replenishments. As the number of replenishments increases, toner deterioration in the developing device 8 and wear of the developing roller 4 progresses. As shown in FIG. 20, by increasing the correction coefficient as the number of replenishments N increases, the corrected inter-replenishment travel distance Lt increases. In other words, the corrected travel distance is a value that is further corrected so that it becomes larger the more times toner is replenished. This allows for earlier judgment of replenishment and end of life, making it possible to prevent fogging and unnecessary toner replenishment.

[0187] Although the fifth embodiment shows an example in which the correction coefficient is determined based on the number of replenishments N, similarly to FIG. 18, the replenishment execution inter-replenishment travel distance threshold L3th may be set according to the number of replenishments N. In this case, similarly to the third embodiment, the correction coefficient may be determined only according to the remaining toner amount T. The greater the number of replenishments N, the smaller the replenishment execution inter-replenishment travel distance threshold L3th is set to. This allows for an early replenishment decision to be made in situations where the number of replenishments is high and toner deterioration in the developing device 8 and wear of the developing roller 4 are likely to progress.

[0188] In the fifth embodiment, the correction coefficient is increased as the number of replenishment times increases, assuming a situation in which low-print-ratio printing is continuously performed. For example, in the image forming apparatus 100, a low-print-ratio print mode is selectable and the image forming apparatus 100 is set to that print mode. If high-print-ratio printing is performed even once, it is considered that toner deterioration and wear of the developing roller 4 will improve.

[0189] In the third to fifth embodiments, the travel distance L and the total travel distance TotalL are changed according to the remaining toner amount T. However, the second parameter used to determine replenishment or the end of life may be changed according to a first parameter related to the progression of toner deterioration or wear of the developing roller. Examples of the first parameter include the operating environment (temperature, humidity, etc.) of the image forming apparatus 100 and the number of toner replenishments N. Examples of the first parameter include the remaining toner amount T, the toner replenishment amount ΔT, the inter-replenishment travel distance RefillL, the total travel distance TotalL, and the corrected inter-replenishment travel distance Lt when toner was last replenished. On the other hand, examples of the second parameter include the total travel distance threshold TotalLth, the replenishment travel distance threshold L1th, the inter-replenishment travel distance threshold L2th, the inter-replenishment travel distance threshold L3th, and the correction coefficient k. The method of changing the second parameter according to the first parameter may be changed so that the replenishment request notification or the end of life notification can be made earlier in situations where toner deterioration or wear of the developing roller is more likely to progress.

[0190] In the above embodiment, the life end notification is given when the total mileage TotalL or the corrected total mileage TotalLt reaches the total mileage threshold TotalLth, but the condition for giving the life end notification is not limited to this. For example, the life end notification may be given when the number of replenishments reaches a predetermined threshold or more.

[0191] The disclosure of this embodiment includes the following configuration. (Configuration 1) a photosensitive drum on whose surface an electrostatic latent image is formed; a developing device including a storage chamber for storing a developer and a developing roller for supplying the developer from the storage chamber to the photosensitive drum, the developing device having a detachable supply container for replenishing the developer to the storage chamber; a notification means for notifying a user; Equipped with The notification means notifies the user of the movement distance of the surface of the developing roller in a predetermined section when the developing device is in use. The image forming apparatus is characterized in that, when a cumulative moving distance accumulated from the beginning reaches or exceeds a predetermined first replenishment determination threshold, a notification is given to prompt the replenishment of the developer. (Configuration 2) The image forming apparatus according to configuration 1, wherein the notification means issues a notification to prompt the developer to be replenished when the inter-replenishment movement distance, calculated by accumulating the movement distance of a predetermined section of the surface of the developing roller since the last time the developer was replenished, becomes equal to or greater than a predetermined second replenishment judgment threshold. (Configuration 3) The image forming apparatus according to configuration 2, wherein the notification means issues a notification to prompt replenishment of the developer when the amount of developer used since the last replenishment of the developer is equal to or less than a predetermined threshold and the distance traveled between replenishments is equal to or greater than the second replenishment judgment threshold. (Configuration 4) The image forming apparatus according to configuration 1, wherein the notification means issues a notification to prompt the user to replenish the developer when the corrected movement distance, which is a value obtained by correcting the movement distance of a predetermined section of the surface of the developing roller based on remaining amount information, which is information related to the amount of developer contained in the storage chamber, and the corrected movement distance accumulated since the last time the developer was replenished, becomes equal to or greater than a predetermined third replenishment judgment threshold. (Configuration 5) 5. The image forming apparatus according to configuration 4, wherein the third replenishment determination threshold value is set to a smaller value as the amount of developer replenished the previous time is smaller. (Configuration 6) The image forming apparatus according to configuration 4 or 5, wherein the correction based on the remaining amount information is performed such that the greater the amount of the developer contained in the containing chamber, the greater the corrected movement distance. (Configuration 7) The image forming apparatus according to configuration 4 or 5, wherein the corrected movement distance is a value that is further corrected so that the larger the amount of developer contained in the storage chamber when the developer was last replenished, the larger the value becomes. (Configuration 8) The image forming apparatus according to configuration 4 or 5, wherein the corrected movement distance is a value that is further corrected so that the larger the inter-replenishment movement distance, which is the sum of the movement distance of a predetermined section of the surface of the developing roller since the previous replenishment of the developer, the larger the value becomes. (Configuration 9) The image forming apparatus according to configuration 4 or 5, wherein the corrected movement distance is a value that is further corrected so that the smaller the amount of developer replenished the previous time, the larger the value becomes. (Configuration 10) The image forming apparatus according to configuration 4 or 5, wherein the corrected movement distance is a value that is further corrected so that the greater the number of times the developer has been replenished, the greater the value becomes. (Configuration 11) An image forming apparatus according to any one of configurations 1 to 10, wherein the notification means changes a second parameter used when determining whether to notify in accordance with a first parameter related to the deterioration of the developer or the progress of wear of the developing roller, so that the notification can be made early in a situation where the deterioration of the developer or the progress of wear of the developing roller is likely to progress. (Configuration 12) The image forming apparatus of configuration 11, wherein the first parameter is at least one of the usage environment of the image forming apparatus, the number of times the developer has been replenished, the amount of developer contained in the storage chamber the last time the developer was replenished, the amount of developer replenished the last time the developer was replenished, the cumulative travel distance from the beginning of use of the developing device the last time the developer was replenished, and the travel distance between replenishments of the developing device the last time the developer was replenished. (Configuration 13) 13. The image forming apparatus according to claim 11, wherein the second parameter is at least one of a first replenishment determination threshold, a second replenishment determination threshold, a third replenishment determination threshold, and a correction coefficient k used to calculate a corrected movement distance. (Configuration 14) a photosensitive drum on whose surface an electrostatic latent image is formed; a developing device including a storage chamber for storing a developer and a developing roller for supplying the developer from the storage chamber to the photosensitive drum, the developing device having a detachable supply container for replenishing the developer to the storage chamber; a notification means for notifying a user; Equipped with The image forming apparatus is characterized in that the notification means notifies that the developing device has reached the end of its life when the cumulative movement distance, calculated by accumulating the movement distance of a specified section of the surface of the developing roller from the beginning of use of the developing device, becomes equal to or greater than a specified life judgment threshold. (Configuration 15) The image forming apparatus according to configuration 14, wherein the notification means notifies that the developing device has reached the end of its life when the corrected cumulative movement distance, which is a value obtained by correcting the movement distance of a predetermined section of the surface of the developing roller based on remaining amount information, which is information related to the amount of developer contained in the storage chamber, and which is calculated from the initial use of the developing device, becomes equal to or greater than a predetermined life judgment threshold. (Configuration 16) 16. The image forming apparatus according to claim 14, wherein the notification means notifies the user that the developing device has reached the end of its life when the number of times the developer has been replenished reaches a predetermined threshold value. (Configuration 17) 17. The image forming apparatus according to any one of configurations 1 to 16, wherein the movement distance of the predetermined section is the movement distance from the start to the end of an image forming operation. (Configuration 18) 18. The image forming apparatus according to any one of configurations 1 to 17, wherein the developing device is included in a cartridge that is detachably attachable to the main body of the image forming apparatus. [Explanation of symbols]

[0192] 1: photosensitive drum, 8: developing device, 16: toner pack, 60: operation panel, 200: control unit, 300: toner amount calculation unit, 400: developing roller travel distance detection unit, 500: determination unit, 501: replenishment request processing unit, 502: life determination processing unit

Claims

1. A photosensitive drum, A developing apparatus comprising: a storage chamber for containing a single-component developer; a developing roller that contacts the photosensitive drum to form a developing section, and in the developing section supplies the single-component developer from the storage chamber to the photosensitive drum; and a developing apparatus to which a supply container for replenishing the single-component developer can be attached and detached to the storage chamber; A notification method for informing the user, Equipped with, The image forming apparatus is characterized in that the notification means provides notification prompting the replenishment of the one-component developer when the cumulative travel distance, calculated by accumulating the travel distance of a predetermined section of the surface of the developing roller from the initial use of the developing apparatus, exceeds a predetermined first replenishment judgment threshold.

2. The image forming apparatus according to claim 1, wherein the notification means provides notification prompting the replenishment of the one-component developer when the distance traveled between replenishments, calculated by accumulating the distance traveled in a predetermined section of the surface of the developing roller since the last replenishment of the one-component developer, exceeds a predetermined second replenishment judgment threshold.

3. The image forming apparatus according to claim 2, wherein the notification means provides notification prompting the replenishment of the one-component developer when the amount of the one-component developer used since the last replenishment of the one-component developer is below a predetermined threshold and the distance traveled between replenishments is equal to or greater than the second replenishment judgment threshold.

4. The image forming apparatus according to claim 1, wherein the notification means provides notification prompting the replenishment of the one-component developer when the corrected travel distance, which is a value obtained by correcting the travel distance of a predetermined section of the surface of the developing roller based on remaining amount information, which is information related to the amount of the one-component developer stored in the storage chamber, becomes equal to or greater than a predetermined third replenishment judgment threshold, since the last replenishment of the one-component developer.

5. The image forming apparatus according to claim 4, wherein the third replenishment judgment threshold is used to be smaller the amount of replenishment when the one-component developer was replenished last time.

6. The image forming apparatus according to claim 4 or 5, wherein, in the correction based on the remaining amount information, the correction is made such that the correction travel distance increases as the amount of the one-component developer contained in the storage chamber increases.

7. The image forming apparatus according to claim 4 or 5, wherein the correction travel distance is a value that has been further corrected so that it becomes larger the larger the amount of the one-component developer contained in the storage chamber when the one-component developer was replenished last time.

8. The image forming apparatus according to claim 4 or 5, wherein the corrected travel distance is a value that is further corrected so that it becomes larger as the inter-replenishment travel distance, which is the sum of the travel distances over a predetermined section of the surface of the developing roller since the previous replenishment of the one-component developer, increases.

9. The image forming apparatus according to claim 4 or 5, wherein the correction travel distance is a value that has been further corrected so that it becomes larger the smaller the amount of the one-component developer supplied when it was supplied last time.

10. The image forming apparatus according to claim 4 or 5, wherein the correction travel distance is a value that has been further corrected so that it becomes larger as the number of times the one-component developer has been replenished increases.

11. The image forming apparatus according to any one of claims 1 to 5, wherein, in situations where the deterioration of the one-component developer or the wear of the developing roller is likely to progress, the notification is given early, and the second parameter used by the notification means when making a decision to give the notification is changed according to a first parameter related to the deterioration of the one-component developer or the wear of the developing roller.

12. The image forming apparatus according to claim 11, wherein the first parameter is at least one of the following: the operating environment of the image forming apparatus, the number of times the one-component developer has been replenished, the amount of the one-component developer contained in the storage chamber at the time of the previous replenishment of the one-component developer, the amount of the one-component developer replenished at the time of the previous replenishment, the cumulative distance traveled by the developing apparatus from the start of use at the time of the previous replenishment of the one-component developer, and the distance traveled by the developing apparatus between replenishments at the time of the previous replenishment of the one-component developer.

13. The image forming apparatus according to claim 11, wherein the second parameter is at least one of the first replenishment decision threshold, the second replenishment decision threshold, the third replenishment decision threshold, and the correction coefficient k used to calculate the corrected travel distance.

14. A photosensitive drum, A developing apparatus comprising: a storage chamber for containing a single-component developer; a developing roller that contacts the photosensitive drum to form a developing section, and in the developing section supplies the single-component developer from the storage chamber to the photosensitive drum; and a developing apparatus to which a supply container for replenishing the single-component developer can be attached and detached to the storage chamber; A notification method for informing the user, Equipped with, The image forming apparatus is characterized in that the notification means notifies that the developing device has reached the end of its lifespan when the cumulative distance traveled by a predetermined section of the surface of the developing roller, accumulated from the initial use of the developing device, exceeds a predetermined lifespan threshold.

15. Claim 14: The notification means provides notification that the developing device has reached the end of its lifespan when the cumulative corrected travel distance, which is a value obtained by correcting the travel distance of a predetermined section of the surface of the developing roller based on remaining amount information, which is information related to the amount of the one-component developer stored in the storage chamber, accumulates from the beginning of use of the developing device and exceeds a predetermined lifespan determination threshold. The image forming apparatus described above.

16. The image forming apparatus according to claim 14 or 15, wherein the notification means provides notification that the developing apparatus has reached the end of its lifespan when the number of times the one-component developer has been replenished exceeds a predetermined threshold.

17. The image forming apparatus according to any one of claims 1 to 5, 14, or 15, wherein the travel distance of the predetermined section is the travel distance from the start to the end of the image forming operation.

18. The image forming apparatus according to any one of claims 1 to 5, 14, or 15, wherein the developing device is included in a cartridge that can be attached to or removed from the main body of the image forming apparatus.

Images