JP7254510B2 - image forming device - Google Patents

Description

The present invention relates to a technique for judging the life of a developing device provided in an image forming apparatus such as a copier, printer, facsimile, or the like using an electrophotographic method, an electrostatic recording method, or the like.

In an image forming apparatus such as a printer using an electrophotographic image forming system (electrophotographic process), an electrophotographic photoreceptor (hereinafter referred to as a "photoreceptor") as an image carrier is uniformly charged, and the charged photoreceptor is used. By selectively exposing the body to light, an electrostatic image is formed on the photoreceptor. The electrostatic image formed on the photoreceptor is visualized as a toner image using toner as a developer. Then, the toner image formed on the photoreceptor is transferred onto a recording material such as a recording paper or a plastic sheet, and heat and pressure are applied to the toner image transferred onto the recording material to transfer the toner image onto the recording material. Image formation is performed by fixing.
Such an image forming apparatus generally requires developer replenishment and maintenance of various process means. In order to facilitate the replenishment of the developer and the maintenance of various process means, the photoreceptor, charging means, developing means, cleaning means, etc. are assembled into a cartridge in a frame, which can be attached to and detached from the main body of the image forming apparatus. A cartridge has been put into practical use. According to the process cartridge system, it is possible to provide an image forming apparatus with excellent usability.
In such a process cartridge, as the number of times of image formation increases, toner that is repeatedly collected without being developed on a photosensitive drum, which is an example of a photosensitive member, is generated. In such a toner, the toner image formation is repeated many times, and the added external additive is released from or embedded in the resin particles that are the base of the toner, causing deterioration. There is In such a case, the toner cannot obtain a desired charge amount, and the toner adheres to the white background portion of the image, so-called fogging may occur. In view of this, Japanese Patent Application Laid-Open No. 2002-200000 proposes a method that calculates the degree of deterioration of toner in an image forming apparatus and integrates the calculated degrees to determine that the developing device has reached the end of its life. Further, in Japanese Patent Application Laid-Open No. 2002-100000, the optimum life of the developing device is determined by taking into consideration the degree of deterioration of the developing roller due to the degree of so-called filming, in which toner and external additives accumulate on the developing roller. Proposed.

Japanese Patent No. 4743273 JP 2016-161645 A

In recent years, as one of the wide-ranging demands of the market, there is a demand for higher image density and wider color tones for the purpose of obtaining richer images. The following techniques are known for that purpose. First, in addition to the image forming mode for obtaining general image density, it has an image forming mode that changes the peripheral speed ratio of the photosensitive drum and the developing roller as a means to achieve high density and increased color. . By doing so, the amount of toner supplied to the photosensitive drum is increased, and the amount of toner on the recording medium is increased, thereby increasing the image density and increasing the color tone.
The inventors have found that if this technique is used to increase the peripheral speed ratio between the photosensitive drum and the developing roller for printing, the deterioration of the developing roller is affected. If the developing roller deteriorates early, the volume resistance value increases, and the charge of the toner on the developing roller becomes difficult to escape to the developing roller, and the toner accumulates the charge. As a result, for example, the toner on the developing roller has an excessive amount of electric charge, and the regulation by the regulation member becomes insufficient. In other words, it is desired to notify the user of the life of the developing device at an appropriate timing.
An object of the present invention is to solve such problems. That is, it is an object of the present invention to provide a technique capable of more appropriately determining the life of a developing device in an image forming apparatus capable of selecting an image forming mode that changes the rotation peripheral speed ratio of a photosensitive drum and a developing roller.

In order to achieve the above object, an image forming apparatus according to the present invention includes a rotatable image carrier;
a developing device having a developer carrier that supplies a developer to the image carrier and develops an electrostatic latent image on the image carrier;
A first mode in which the developer carrier rotates with respect to the image carrier at a first peripheral speed ratio, and a second mode in which the developer carrier rotates with respect to the image carrier at a ratio greater than the first peripheral speed ratio. and a second mode rotating at a peripheral speed ratio of 2, wherein
storage means for storing a first correction coefficient corresponding to a rotation peripheral speed ratio between the image carrier and the developer carrier and a life threshold value of the developing device;
Based on first driving amount information when the developer bearing member operates in the first mode and second driving amount information when the developer bearing member operates in the second mode, the developing a control means for accumulating or decrementing the driving amount information of the developer bearing member with respect to the life judgment value of the apparatus, and updating the life judgment value;
The control means reads out the first correction coefficient stored in the storage means and uses it for the first drive amount information and/or the second drive amount information, so that the same driving of the developer carrier is performed. With respect to the amount, the magnitude of the driving amount information that is accumulated or progressively decreased by the second driving amount information is made larger than the magnitude of the driving amount information that is accumulated or gradually decreased by the first driving amount information, and the life It is characterized by updating the judgment value.
Further, in order to achieve the above object, the image forming apparatus of the present invention includes:
a rotatable image carrier;
a developing device having a developer carrier that supplies a developer to the image carrier and develops an electrostatic latent image on the image carrier;
A first mode in which the developer carrier rotates with respect to the image carrier at a first peripheral speed ratio, and a second mode in which the developer carrier rotates with respect to the image carrier at a ratio greater than the first peripheral speed ratio. and a second mode rotating at a peripheral speed ratio of 2, wherein
storage means for storing a first correction coefficient corresponding to a rotation peripheral speed ratio between the image carrier and the developer carrier and a life threshold value of the developing device;
A first total value of drive amount information obtained by accumulating first drive amount information when the developer carrier operates in the first mode, and a second total value when the developer carrier operates in the second mode. a control means for accumulating a second total value of the driving amount information;
The control means is
Read out the first correction factor, use it for the first sum value and/or the second sum value, and determine life by summing based on the first sum value and the second sum value or subtracting from an initial value Calculate the value of
A magnitude of the sum or the subtraction based on the second sum value is larger than a magnitude of the sum or the subtraction based on the first sum value at the same driving amount of the developer carrier.

According to the present invention, even in an image forming apparatus having a plurality of image forming modes with different peripheral speed ratios between the photosensitive drum and the developing roller, it is possible to appropriately determine the life of the developing device.

Schematic diagram of image forming apparatus Schematic diagram of a drum cartridge Schematic diagram of developer cartridge Hardware block diagram of image forming apparatus Graph showing the relationship between the rotation peripheral speed ratio and the current value between the photosensitive drum and the developing roller Developing cartridge life judgment sequence chart Life judgment sequence chart for another developing cartridge Life judgment sequence chart for another developing cartridge Life judgment sequence chart for another developing cartridge Example of change in remaining life of developing cartridge The film thickness of the carrier transfer layer of the photosensitive drum and the value of the current flowing between the developing rollers An example of transition of remaining life of developing cartridge in Example 3

BEST MODE FOR CARRYING OUT THE INVENTION A mode for carrying out the present invention will be exemplarily described in detail below based on an embodiment with reference to the drawings. However, the dimensions, materials, shapes and relative arrangement of the components described in this embodiment should be appropriately changed according to the configuration of the device to which the invention is applied and various conditions. That is, it is not intended to limit the scope of the present invention to the following embodiments.

[Example 1]
An overall configuration of an embodiment of an electrophotographic image forming apparatus (image forming apparatus) will be described. FIG. 1 is a cross-sectional view of an image forming apparatus 100 of this embodiment. The image forming apparatus 100 of this embodiment is a full-color laser beam printer that employs an in-line method and an intermediate transfer method. The image forming apparatus 100 can form a full-color image on a recording material (for example, recording paper, plastic sheet, cloth, etc.) according to image information. Image information is input to the image forming apparatus main body from an image reading device connected to the image forming apparatus main body or a host device such as a personal computer communicably connected to the image forming apparatus main body. Image forming apparatus 100 includes SY, SM, SC, and SK for forming images of yellow (Y), magenta (M), cyan (C), and black (K), respectively, as a plurality of image forming units. have. In this embodiment, the image forming units SY, SM, SC, and SK are arranged in a row in a direction crossing the vertical direction.

The image forming apparatus 100 of this embodiment integrates the photosensitive drum 1, the charging roller 2, the cleaning blade 6, and the drum cartridge frame 11 shown in FIG. It is configured as a drum cartridge 210 . Similarly, the developing roller 4, the toner supply roller 5, the toner amount regulating member 8, the developing chamber 20a, and the developer container 22 constituting the developer storage chamber 20b shown in FIG. A developing cartridge 200 is used.
The aforementioned image forming section comprises drum cartridges 210 (210Y, 210M, 210C, 210K) and developer cartridges 200 (200Y, 200M, 200C, 200K). These drum cartridge 210 and developing cartridge 200 can be attached to and detached from the image forming apparatus 100 via attachment means such as an attachment guide and a positioning member provided in the main body of the image forming apparatus. In this embodiment, the drum cartridges 210 and developing cartridges 200 for each color have the same shape, and the developing cartridges 200 for each color contain yellow (Y), magenta (M), and cyan (C) inks, respectively. , and black (K). In this embodiment, the drum cartridge 210 and the developing cartridge 200 are separately attachable and detachable.

The photosensitive drum 1 is rotationally driven by driving means (driving source) (not shown). A scanner unit (exposure device) 30 is arranged around the photosensitive drum 1 . The scanner unit 30 is exposure means for forming an electrostatic image (electrostatic latent image) on the photosensitive drum 1 by irradiating a laser based on image information. Writing of laser exposure is performed from a position signal called BD in the polygon scanner for each scanning line in the main scanning direction (direction orthogonal to the conveying direction of the recording material 12). On the other hand, in the sub-scanning direction (conveyance direction of the recording material 12), it is delayed by a predetermined time from the TOP signal starting from a switch (not shown) in the conveyance path of the recording material 12. FIG. As a result, the four process stations Y, M, C, and K can always perform laser exposure on the same position on the photosensitive drum 1 .

An intermediate transfer belt 31 serving as an intermediate transfer member for transferring the toner images on the photosensitive drums 1 onto the recording material 12 is arranged to face the four photosensitive drums 1 . An intermediate transfer belt 31, which is an endless belt as an intermediate transfer member, contacts all the photosensitive drums 1 and circulates (rotates) in the arrow B direction (counterclockwise direction). Four primary transfer rollers 32 as primary transfer means are arranged side by side on the inner peripheral surface side of the intermediate transfer belt 31 so as to face each photosensitive drum 1 . A primary transfer bias power source (high voltage power source) serving as primary transfer bias applying means (not shown) applies a bias having a polarity opposite to the normal charging polarity of the toner to the primary transfer roller 32 . As a result, the toner image on the photosensitive drum 1 is transferred (primary transfer) onto the intermediate transfer belt 31 .

A secondary transfer roller 33 as a secondary transfer unit is arranged on the outer peripheral surface side of the intermediate transfer belt 31 . A secondary transfer bias power supply (high voltage power supply) serving as secondary transfer bias applying means (not shown) applies a bias having a polarity opposite to the normal charging polarity of the toner to the secondary transfer roller 33 . As a result, the toner image on the intermediate transfer belt 31 is transferred (secondary transfer) onto the recording material 12 . For example, when forming a full-color image, the above-described processes are sequentially performed in the image forming stations SY, SM, SC, and SK, and the toner images of the respective colors are sequentially superimposed and primarily transferred onto the intermediate transfer belt 31 . After that, the recording material 12 is conveyed to the secondary transfer portion in synchronization with the movement of the intermediate transfer belt 31 . The four-color toner images on the intermediate transfer belt 31 are collectively secondary-transferred onto the recording material 12 by the action of the secondary transfer roller 33 which is in contact with the intermediate transfer belt 31 via the recording material 12 . be.

The recording material 12 onto which the toner image has been transferred is conveyed to a fixing device 34 as fixing means. The toner image is fixed on the recording material 12 by applying heat and pressure to the recording material 12 in the fixing device 34 .

[Drum cartridge]
The configuration of the drum cartridge 210 installed in the image forming apparatus 100 of this embodiment will be described. FIG. 2 is a cross-sectional (main cross-sectional) view of the drum cartridge 210 of the present embodiment viewed along the longitudinal direction (rotational axis direction) of the photosensitive drum 1. FIG.
The photosensitive drum 1 is rotatably attached to the drum cartridge 210 via a bearing (not shown). The photosensitive drum 1 receives the driving force of a driving motor as photosensitive drum driving means (driving source a), and is rotationally driven in the direction of the arrow A in the image forming operation.

The photosensitive drum 1 is an organic photoreceptor in which an outer peripheral surface of an aluminum cylinder with a diameter of 30 mm is coated with an undercoat layer, a high resistance layer, a carrier layer, and a carrier transfer layer, which are functional films, in this order. Since the carrier transfer layer is scraped and worn out by the image forming operation, the film thickness must be formed according to the life of the drum cartridge 210 . In order to meet recent market demand and achieve a longer life, the thickness is set to 25 μm in this embodiment.

Further, the charging roller 2 and the cleaning blade 6 made of an elastic material are arranged in the drum cartridge 210 so as to be in contact with the peripheral surface of the photosensitive drum 1 . Further, a drum cartridge frame 11 having a storage space for storing toner on the photosensitive drum 1 removed by the cleaning blade 6 is provided. A charging bias power supply (high voltage power supply) serving as a charging bias applying means (not shown) applies a sufficient bias to the charging roller 2 so that any charge can be placed on the photosensitive drum 1 . In this embodiment, the bias applied is set so that the potential (charging potential: Vd) on the photosensitive drum 1 is -500V. A laser 35 is emitted from the scanner unit 30 based on image information to form an electrostatic image (electrostatic latent image) on the photosensitive drum 1 . As a result of the irradiation with the laser 35, the charge on the surface of the photosensitive drum 1 disappears due to the carriers from the carrier generating layer, and the potential of the irradiated portion decreases. As a result, an electrostatic latent image is formed in which the irradiated portion of the laser 35 has a predetermined bright portion potential (Vl) and the non-irradiated portion has a predetermined dark portion potential (Vd).

Further, the drum cartridge 210 is provided with a non-volatile memory (hereinafter referred to as O memory m1) as a storage means. The O memory m1 stores information such as the number of rotations of the photosensitive drum 1 and the manufacturing number, and the amount of usage of the drum cartridge can be grasped based on the information held by the O memory m1. The O memory m1 is configured to be able to communicate (write and read information) with the controller 300 of the image forming apparatus 100 shown in FIG.

[Development cartridge]
Next, the configuration of the developing cartridge 200 mounted on the image forming apparatus 100 of this embodiment will be described. FIG. 3 is a cross-sectional (main cross-sectional) view of the developing cartridge 200 of the present invention viewed along the longitudinal direction (rotational axis direction) of the developing roller 4. FIG.

The developing cartridge 200 includes a developing chamber 20a, a developer containing chamber 20b, a developing roller 4, a toner supply roller 5, and a developer container 22 constituting the developing chamber 20a and the developer containing chamber 20b. The developer containing chamber 20b is arranged below the developing chamber 20a. Toner 9 as a developer is stored inside the developer storage chamber 20b. In this embodiment, the normal charging polarity of the toner 9 is negative, and the case of using negative charging toner will be described below. However, the present invention is not limited to negatively chargeable toners.

Further, the developer containing chamber 20b is provided with a developer conveying member 21 for conveying the toner 9 to the developing chamber 20a. are transported to The developer conveying member 21 is composed of an elastic sheet-like member extending in the longitudinal direction of the cartridge.

In the developing chamber 20a, there is a developing roller 4 as a developer carrying member which is in contact with the corresponding photosensitive drum 1 and rotates in the illustrated arrow D direction by receiving the driving force of a driving motor as developing driving means (driving source a). is provided. In this embodiment, the developing roller 4 and the photosensitive drum 1 rotate so that their surfaces move in the same direction at the facing portion (contact portion). Further, the developing roller 4 is provided with a conductive elastic rubber layer having a predetermined volume resistance around a metal core. A bias sufficient to develop and visualize the electrostatic latent image on the photosensitive drum 1 as a toner image is applied from a developing bias power supply (high voltage power supply) as developing bias applying means (not shown).

Further, inside the developing chamber 20a, a toner supply roller (hereinafter simply referred to as a "supply roller") 5 for supplying the toner conveyed from the developer storage chamber 20b to the developing roller 4, and a supply roller 5 supply toner. A toner amount regulating member (hereinafter simply referred to as "regulating member") 8 is arranged for regulating the amount of toner coated on the developing roller 4 and for imparting electric charges.

Further, the developing cartridge 200 is provided with a non-volatile memory (hereinafter referred to as DT memory m2) as a storage means. The DT memory m2 stores the total driving amount of the developing roller 4, the remaining amount of toner, and the like, and the usage amount of the developing cartridge can be grasped based on the information held by the DT memory m2. The DT memory m2 is configured to be able to communicate (write and read information) with the controller 300 of the image forming apparatus 100 in a non-contact manner or in contact via an electrical contact (not shown).

[Image Forming Mode]
The image forming apparatus 100 of this embodiment has two image forming modes. The first mode is an image forming mode for obtaining a normal image density (hereinafter referred to as normal mode). In the second mode, while lowering the dark area potential on the image carrier, the rotation peripheral speed ratio between the photosensitive drum 1 as the image carrier and the developing roller 5 as the developer carrier is increased to select high density and color tone. An image forming mode (hereinafter referred to as a high density mode) for obtaining an increase in range.
Table 1 below shows specific differences in control between the normal mode and the high density mode in this embodiment.

表１中の暗部電位Ｖｄは、帯電ローラ２で感光ドラム１表面を帯電した後の感光ドラム１表面の電位である。また、明部電位Ｖｌは、レーザ３５が照射された後の感光ドラム１表面の電位である。現像電位Ｖｄｃは現像ローラ４に現像バイアス電源によって印加される電位である。

The dark area potential Vd in Table 1 is the potential of the surface of the photosensitive drum 1 after the surface of the photosensitive drum 1 is charged by the charging roller 2 . Also, the light area potential Vl is the potential of the surface of the photosensitive drum 1 after the laser 35 is irradiated. The development potential Vdc is a potential applied to the development roller 4 by the development bias power supply.

The rotation peripheral speed ratio in this embodiment is the rotation peripheral speed ratio of the developing roller 4 when the rotation peripheral speed of the photosensitive drum 1 is assumed to be one. Specifically, in the normal mode, the rotational peripheral speed of the photosensitive drum 1 is set to 200 mm/sec, and the rotational peripheral speed of the developing roller 4 is set to 280 mm/sec. On the other hand, in the high density mode, the rotational peripheral speed of the photosensitive drum 1 is set at 100 mm/sec, and the rotational peripheral speed of the developing roller 4 is set at 250 mm/sec. Here, the reason why the rotation peripheral speed of the photosensitive drum 1 is slowed down in the high density mode is that the amount of toner on the recording material 12 is increased, so that good fixability is ensured. Although the heat applied to the recording material 12 in the fixing device 34 may be increased, the power consumption is increased.

As shown in Table 1, the difference between the development potential Vdc and the light area potential Vl (hereinafter referred to as development contrast) is set larger in the high density mode than in the normal mode. As a result, the amount of toner coated on the developing roller 4 that is developed onto the photosensitive drum 1 is greater in the high-density mode than in the normal mode. Further, by setting the rotation peripheral speed ratio between the photosensitive drum 1 and the developing roller 4 to be large, the amount of toner supplied from the developing roller 4 per unit area of the photosensitive drum 1 increases. With these two effects, the amount of toner on the recording material 12 can be increased, and an image with high density and wide color gamut can be printed.

[Remaining amount of toner detection method]
Here, a method for detecting the remaining amount of toner by the video counting method used in this embodiment will be described. FIG. 4 shows a hardware block diagram of the image forming apparatus in this embodiment. The control unit 300 of the image forming apparatus 100 includes a correction information acquisition unit that performs various calculation processes and acquires correction amount information such as a correction distance of the developing roller, which will be described later, and a remaining amount acquisition unit that acquires information about the remaining amount of toner. A CPU 501 that also serves as a Also provided is a memory 502 on the main body side of the apparatus, in which information necessary for controlling the motor drive unit 511 and the high-voltage power supply 512 is stored. Further, the information stored in the O memory m1 of the drum cartridge 210 and the DT memory m2 of the developing cartridge 200 is input/output from the input/output I/F 503 to the CPU 501 via the memory communication unit 500, and exchanged with the control unit 300. Is going. Also, the control unit 300 is connected to a video count measuring unit 305 that measures a video signal output by an image forming operation.
The principle of toner remaining amount detection using video counting will be described. Another control device (not shown) is arranged upstream of the control unit 300. A laser driving signal (video signal) from the control device is branched, and a video signal is generated during a period of forming an electrostatic latent image on the photosensitive drum. Sample the signal. The sampled video signal is input to the hardware counter in the control unit 300 , the ON/OFF state of the video signal is counted, and the CPU 501 reads the value. This read value indicates the amount of toner consumed, and a value obtained by subtracting the count value from a predetermined initial value becomes information indicating the remaining amount of toner. If the number of ON states of the video signal is divided by the number of ON states that is measured when a black image is printed on the entire area of the recording material where the image is to be printed, the number of ON states for forming the electrostatic latent image is calculated. It is possible to obtain the ratio of how many lasers are lit. An electrostatic latent image is formed on the portion irradiated with the laser, and toner adheres to the portion. Therefore, the remaining amount of toner can be calculated based on the lighting ratio of the laser. Note that the counting by the video count measurement unit 305 specifically corresponds to the counting of the ON video signal for irradiating the laser beam, but the sampling period does not have to be synchronized with the video clock of the video signal. If sampling is performed at a period shorter than the video clock, the video count measurement unit 305 may count pixel information asynchronously with the video clock. Then, the CPU 501 provided in the control unit 300 calculates the remaining amount of the toner 9 in the developing cartridge 200 from the measured video count value.

A video count measurement unit 305 measures pixel information (video count value VCn) of an output image. In this embodiment, one recording material 12 to be output is taken as one video count value VCn. The CPU 501 calculates the remaining amount of toner according to the following procedure. First, the video count value VCn measured by the video count measuring section 305 is added to the cumulative video count value VCr from the start of use of the developing cartridge 200 stored in the DT memory m2 of the developing cartridge 200, and the total video count value VCt is obtained. Calculate
VCt=VCr+VCn

Next, the CPU 501 calculates the toner remaining amount TP in the developing cartridge 200 from the video count threshold value VCth stored in the DT memory m2 and the total video count value VCt.
TP [%] = (1-VCt/VCth) x 100
Then, the CPU 501 writes the total video count value VCt to the DT memory m2 as the cumulative video count value VCr.
Here, when the toner remaining amount TP=100%, the toner 9 in the developing cartridge 200 is full, indicating that the developing cartridge 200 is new. Further, when the toner remaining amount TP=0%, the remaining amount of toner 9 in the developing cartridge 200 is almost exhausted, indicating that the developing cartridge 200 is to be replaced.
In this embodiment, the video count threshold value VCth at which the remaining toner amount TP is 0% is such that insufficient toner supply from the supply roller 5 to the development roller 4 occurs even when a high print image such as a solid image is printed. It is set based on the remaining amount of the toner 9 that is not used. Therefore, the actual remaining amount of toner may be set to TP=5%, for example.

[Developing Roller Life Calculation Method]
Next, a method for calculating the life of the developing roller 4 will be described. The life of the developing roller 4 is determined according to the running distance Wu of the developing roller 4 . In the following description, the traveling distance Wu is used as an example of driving amount information indicating how much the developing roller 4 has been driven. , various parameters can be used. For example, the total driving time of the developing cartridge 200 or the total number of revolutions of the developing roller 4 may be used. Alternatively, the number of prints formed using the developing cartridge 200 may be used.
The image forming apparatus 100 is provided with a developing roller travel distance measuring unit 302 that measures the travel distance Wu of the developing roller 4. The CPU 501 measures the travel distance Wu of the developing roller 4 using the developing roller travel distance correction coefficient k. The travel distance Wu is corrected.

The developing roller traveling distance measuring unit 302 measures the traveling distance Wu from the driving time Td of the developing cartridge 200, the process speed Ps of the image forming apparatus 100, and the peripheral speed ratio Sr of the developing roller 4 to the photosensitive drum 1.
Wu = Td x Ps x Sr
Here, the running distance Wu represents how far a point on the surface of the developing roller 4 has progressed due to the rotation of the developing roller 4 . Further, the process speed Ps of the image forming apparatus 100 is the rotation speed of the photosensitive drum 1 .

The CPU 501 reads the developing roller running distance correction coefficient k, which is the first correction coefficient stored in the DT memory m2 as a coefficient acquisition unit, according to the image forming mode. More specifically, the developing roller running distance correction coefficient k is read according to the peripheral speed ratio between the photosensitive drum 1 and the developing roller 4 . For example, the developing roller traveling distance correction coefficient k read by the CPU 501 can be k=1 in the normal mode and k=1.5 in the high density mode.
Then, the CPU 501, as a corrected distance obtaining unit, multiplies a predetermined developing roller traveling distance Wu by a developing roller traveling distance correction coefficient k to calculate a corrected developing roller traveling distance Hu.
Hu=Wu×k

Next, the corrected developing roller travel distance Hu is added to the accumulated developing roller travel distance HTn _-1 from the start of use of the developing cartridge 200 stored in the DT memory m2. By doing _so , the total post-correction developing roller travel distance HT _n (n=1, ₂ . do.
_HTn = HTn _-1 + Hu

Then, from the developing roller travel distance threshold value Wth stored in the DT memory m2 and the latest accumulated developing roller travel distance _HTn , the developing roller remaining life DP is calculated by the following formula.
DP [%] = (1- _HTn /Wth) x 100
It should be noted that the developing roller travel distance threshold Wth corresponds to a life threshold relating to the life of the developing roller.

Then, the latest accumulated developing roller traveling distance HT _n (life judgment value) is written in the DT memory m2 as the accumulated developing roller traveling distance HT _n−1 at the time of the next life judgment, and updated.
Here, when the developing roller remaining life DP=100%, it means that the developing cartridge 200 is new. Further, when the developing roller remaining life DP≦0%, it indicates that it is time to replace the developing cartridge 200 .

In this embodiment, the developing roller traveling distance threshold value Wth is set based on the developing roller traveling distance at which the control member 8 does not sufficiently regulate the amount of toner coated on the developing roller 4 , that is, a so-called regulation failure occurs.

Here, the relationship between the running distance of the developing roller and the poor regulation will be described. The supply roller 5, the regulating member 8, and the surface of the photosensitive drum 1 are in contact with the developing roller 4 with a predetermined potential difference. At this time, a current flows through the developing roller 4, and the resistance value of the developing roller 4 increases (energization deterioration). When the resistance value of the developing roller 4 increases, the charge held by the toner on the developing roller 4 becomes difficult to escape, and the charge amount of the toner increases. When the adhesive force to the developing roller 4 increases and exceeds the regulating force of the regulating member 8, the regulating force becomes insufficient, resulting in defective regulation.
The energization deterioration changes depending on the magnitude of the current flowing through the developing roller 4 . When the rotation peripheral speed ratio between the photosensitive drum 1 and the developing roller 4 changes, the current flowing through the developing roller increases as the rotation peripheral speed ratio increases, as shown in FIG. In other words, the larger the rotational peripheral speed ratio, the more progressed deterioration due to electrical conduction. If there are modes with different rotation peripheral speed ratios, it is necessary to correct them. In addition, the susceptibility to electrical deterioration varies depending on the characteristics of the developing roller. Since the specifications of the developing roller may change, it is preferable to store the correction coefficients in the DT memory m2 mounted on the developing cartridge 200. FIG. However, it is not limited to this, and may be stored in the memory of the image forming apparatus main body.

[Development cartridge life judgment sequence]
FIG. 6 is a sequence chart for judging the life of the developing cartridge 200 in the first embodiment. Based on the information in the DT memory m2 mounted on the developing cartridge 200, the CPU 501 incorporated in the control unit 300 performs the processing shown in the flow chart of FIG. Notify the user of the results.

The flowchart shown in FIG. 6 will be described. First, the image forming apparatus 100 receives print data based on a document created by an external computer through the external I/F 504 (S101).
The CPU 501 selects the normal mode if, for example, "0" is set in the setting information included in the print data, and selects the high-density mode if "1" is set in the setting information, and executes subsequent processing. (S102).

Next, the CPU 501 starts the image forming operation of the image forming apparatus 100 including the developing cartridge 200 (S103). In this image forming operation, the setting of the charging potential of the charging roller 2, the development potential of the developing roller 4, and the rotational driving of the photosensitive drum 1 and the developing roller 4 having a predetermined rotation peripheral speed ratio, etc., which are described in Table 1, are performed. , including all the operations necessary for image formation. Note that when the driving of the developing roller 4 is started, the running distance Wu is measured by the CPU 501, and such measurement processing is also included in the image forming operation here. The travel distance Wu measured when the normal mode is selected in S101 corresponds to the first driving amount information of the first mode, and the travel distance Wu measured when the high density mode is selected corresponds to the second driving amount information. It corresponds to the second driving amount information of the mode.

Next, the CPU 501 reads the developing roller running distance correction coefficient k corresponding to the image forming mode selected in S102 from the DT memory m2 (S104). For example, the CPU 501 reads k=1.5 if the image forming mode selected by the CPU 501 in S102 is the high density mode, or k=1 if the normal mode. If the correction coefficient of the selected image forming mode is 1, the CPU 501 may skip the process of S102 because there is no need for correction.

Next, the CPU 501 uses the read developing roller travel distance correction coefficient k to calculate the post-correction developing roller travel distance Hu (S105). The timing at which the CPU 501 calculates the post-correction developing roller running distance Hu may be after the end of printing or at a predetermined interval. In either case, the object of calculation is the uncalculated developing roller traveling distance Wu.

Then, the CPU 501 calculates the latest accumulated developing roller traveling distance as a life judgment value from the corrected developing roller traveling distance Hu and the previous accumulated developing roller traveling distance HT _n−1 stored in the DT memory m2. A distance HT _n is calculated (S106).
Thereafter, the CPU 501 compares the latest cumulative developing roller travel distance _HTn with the travel distance threshold Wth, and determines whether the latest cumulative developing roller travel distance _HTn exceeds the travel distance threshold Wth (S107). Then, if _HTn exceeds Wth, the CPU 501 writes the latest accumulated developing roller travel distance _HTn , which is the total post-correction developing roller travel distance, to the DT memory m2 (S109). After that, the user is notified that the development cartridge 200 has reached the end of its life by using a notification means through the external I/F 504 (S110). The notification means may be a display means such as a monitor or an audio speaker, but is not limited to these. For example, a message may be sent to an external device such as a PC connected to the image forming apparatus. good.

Further, in S107, if the latest cumulative developing roller travel distance _HTn , which is the post-correction total developing roller travel distance, does not exceed the travel distance threshold value Wth, the CPU 501 calculates the latest cumulative developing roller travel distance _HTn . The DT memory m2 is written and updated (S108). Then, preparations are made for the next image formation.

In the above description, the life of the developing roller is determined based on whether or not the total post-correction developing roller travel distance _HTn exceeds the travel distance threshold value Wth, but the present invention is not limited to this. That is, in S106, the CPU 501 obtains the developing roller remaining life DP using the following formula, and the life of the developing roller may be determined based on whether DP is 0 or less than a predetermined value.
DP [%] = (1- _HTn /Wth) x 100
The method using the developing roller remaining life DP is the same as in FIG. 8 described later.

On the other hand, after receiving the image information based on the print data (S111), the CPU 501 measures the video count value VC with the video count measurement unit 305 and calculates the total video count value VCt (S112). After that, the CPU 501 calculates the remaining toner amount TP (S113), and determines whether the remaining toner amount is low, that is, whether the remaining toner amount TP is 0% or less (below a predetermined threshold remaining amount). (S114). If the remaining toner amount TP has reached 0% or less, the CPU 501 writes the cumulative video count value VCr into the DT memory m2 (S116), and notifies the user that the developing cartridge 200 has reached the end of its life (S110). . On the other hand, if the toner remaining amount TP has not reached 0% or less, the CPU 501 writes the cumulative video count value VCr into the DT memory m2 (S115), and the image forming apparatus 100 prepares for the next image formation. conduct.

As a method for determining whether or not the remaining amount of toner is low, calculation of the remaining amount of toner TP has been described, but the present invention is not limited to this. For example, since the total video count value VCt indicates the amount of toner consumption itself, the CPU 501 determines whether the total video count value Vct exceeds a predetermined threshold and determines whether the remaining amount of toner is low. Also good. Also, although the remaining toner amount detection method using the video count method has been described as an example, the present invention is not limited to this. For example, a residual amount detection method using capacitance or a light transmission method may be used, or both of them may be used. Specifically, when the remaining amount of toner obtained by the video counting method is equal to or less than a predetermined amount of remaining toner, either the capacitance method or the light transmission method may be used. In other words, a configuration may be adopted in which a more suitable remaining amount acquisition method is selected according to the degree of the remaining amount of toner. Note that the electrostatic capacitance method uses an electrode (for example, a conductive member is attached to the inner wall of the developer storage chamber) that changes the detected capacitance in response to changes in the state of the toner inside the developer storage chamber. It is a method of obtaining the amount of toner based on the change in capacitance applied. Since this is a conventionally well-known method, detailed description thereof will be omitted. The light transmission method uses a light source for irradiating the inside of the developer storage chamber with light and a light receiving section for receiving the light that has passed through the storage chamber. A way to get the quantity. This method is also a conventionally known method, and a detailed description thereof will be omitted. The same applies to the flow charts described later.

In the first embodiment that executes this series of flowcharts, the running distance Wu of the developing roller 4 is corrected with the developing roller running distance correction coefficient k according to the image forming mode selected by the user. By doing so, it is possible to properly determine the life of the developing cartridge 200 and notify the user. In addition, the detection result of the toner remaining amount is also used to detect that the toner amount in the developing cartridge 200 has almost run out. As a result, the life of the developing cartridge 200 due to the remaining amount of toner can be notified in addition to the life due to deterioration of the developing roller 4, so that the user can be notified of the life of the developing cartridge 200 more appropriately.

Here, with reference to FIG. 10, the difference in the developing roller travel distance _HTn after total correction between when printing is performed in the normal mode and when printing is performed in the high density mode will be specifically described. FIG. 10(a) shows a case where a given pattern is printed in both the normal mode and the high density mode. The horizontal axis indicates the number of prints, and the vertical axis indicates the remaining amount of toner TP. Even when the same pattern is printed, the high-density mode uses a larger amount of toner, so the inclination is different. In the normal mode, no problem occurred until the remaining toner amount TP reached 0%. On the other hand, in the case of the high-density mode, a regulation failure occurred due to deterioration of the developing roller due to electrification. This is the point indicated by point A. FIG. 10(b) shows the remaining life DP of the developing roller 4 converted from the horizontal axis of FIG. 10(a). As indicated by point A in FIG. 10B, neither the remaining toner amount TP nor the remaining life DP of the developing roller reaches 0%. It shows that it is broken.

FIG. 10C shows correction of the development roller life by applying a correction coefficient k = 1.5 to the life of the developing roller when printing in the high-density mode, with the correction coefficient k = 1 when printing in the normal mode. is shown. As a result, image defects such as poor regulation did not occur until the remaining life DP of the developing roller 4 was 0%. Therefore, by correcting the running distance W of the developing roller 4, it is possible to notify the end of the life of the developing cartridge 200 before an image problem such as poor regulation due to deterioration of the developing roller 4 occurs.

[First Another Developing Cartridge Life Judgment Sequence]
In the description of FIG. 6, the post-correction developing roller travel distance Hu is accumulated to HT _n−1 corresponding to the previous total post-correction developing roller travel distance, and the latest cumulative post-correction developing roller travel distance (total travel distance) HT _{n is} obtained. is obtained at any time to determine the life of the developing roller. However, it is not limited to this. For example, the post-correction developing roller traveling distance Hu is decremented from the developing roller travelable distance TD (Total Distance) as an initial value at the start of use of the developing cartridge 200 stored in the DT memory m2. By doing so, the travelable distance _HT'n may be calculated as a life judgment value for judging the life of the developing roller. Note that HT ₀ matches the developing roller travelable distance TD as an initial value.
Ht′ _n =HT _n−1 −Hu
Then, the calculated developing roller life DP' is calculated by the following formula using the developing roller running distance threshold value Wth stored in the DT memory m2.
DP' [%] = ( _HT'n /Wth) x 100

Hereinafter, the developing cartridge life judgment sequence by the cumulative decrease processing of the CPU 501 will be described in detail using the flowchart of FIG. First, the processing from S201 to S205 in FIG. 7 is the same as the processing from S101 to S105 described with reference to FIG. 6, so detailed description thereof will be omitted. Next, the corrected developing roller travel distance Hu is decremented from the initial value TD stored in the DT memory m2 or from the previous travelable distance HT'n _-1 to calculate the latest travelable distance _HT'n (S206). ). Note that this latest travelable distance _HT'n corresponds to the life judgment value.
Then, the CPU 501 compares the latest possible travel distance _HT'n with the travel distance threshold Wth to determine whether the latest travelable distance _HT'n is below the travel distance threshold Wth (S207). If the CPU 501 determines in S207 that the travelable distance _HT'n is below the travel distance threshold value Wth, the CPU 501 writes the reduced travelable distance _HT'n to the DT memory m2 (S209). After that, the user is notified that the development cartridge 200 has reached the end of its life by using a notification means through the external I/F 504 (S110).

On the other hand, if the latest possible travel distance _HT'n is not below the travel distance threshold value Wth, the CPU 501 writes the latest possible travel distance _HT'n into the DT memory m2 for updating (S108), and updates the next image. Prepare for formation. Other processes are the same as those in the flowchart shown in FIG. 6, so detailed description thereof will be omitted.
In the above description, the life of the developing roller is determined based on whether or not the travelable distance _HT'n is less than the travel distance threshold value Wth, but the present invention is not limited to this. That is, in S206, the CPU 501 obtains the developing roller remaining life DP' using the following equation, and the life of the developing roller may be determined based on whether DP' is 0 or less than a predetermined value.
DP' [%] = ( _HT'n /Wth) x 100
The method of using the developing roller remaining life DP' is the same as in FIG. 9, which will be described later.
It should be noted that the frequency with which the processes of S205 to S207 are executed is not limited to a specific frequency. For example, the processing of S205 to S207 may be performed on the traveling distance Wu that is measured by the CPU 501 every second. Alternatively, the processing of S205 to S207 may be performed on the traveling distance Wu measured from the start of the print job each time the print job is completed. Furthermore, the process of S205 may be performed each time a predetermined number of print jobs are completed. The same applies to S105 to S107 in FIG. 6 described above.

[Second Different Developing Cartridge Life Judgment Sequence]
6 and 7, the CPU 501 updates the post-accumulated developing roller travel distance _HTn and the travelable distance _HT'n at a predetermined frequency as needed to determine whether the developing cartridge 200 has reached the end of its life. I explained to judge whether or not. However, a similar effect can be obtained with another lifespan determination sequence.
For example, a total developing roller travel distance Wt ₀ in the normal mode and a total developing roller travel distance Wt ₁ in the high-density mode are stored, respectively, and the CPU 501 determines the developing cartridge 200 based on the stored Wt ₀ and Wt ₁ . You can judge the life of As for the subscripts of Wt, "0" means the normal mode and "1" means the high density mode. The form will be described in detail below with reference to the flow chart of FIG.

First, the processing from S301 to S303 in FIG. 8 is the same as the processing from S101 to S103 described with reference to FIG. 6, so detailed description thereof will be omitted. Next, the CPU 501 updates Wt ₀ or Wt ₁ based on the image forming mode selected in S302 and the travel distance Wu measured in S303 (S304). For example, if the image forming mode selected in S302 is the high-density mode, the traveling distance Wu measured in S303 is added to the developing roller total traveling distance Wt ₁ , and the CPU 301 calculates the latest Wt ₀ and Wt Get ₁ . Here, _Wt0 is the first total value obtained by accumulating the first driving amount information, which is the traveling distance Wu measured in the normal mode, and _Wt1 is the second driving amount information, which is the traveling distance Wu measured in the high density mode. respectively, and will be described in this terminology below.

Next, the CPU 501 reads the developing roller traveling distance correction coefficient k corresponding to the image forming mode from the DT memory m2 (S305). Then, the CPU 501 calculates the corrected developing roller traveling distance Hu ₀ in the normal mode and the corrected developing roller traveling distance Hu ₁ in the high density mode based on the developing roller traveling distance correction coefficient k read in S305 (S306). ). For example, when the correction coefficient k for the normal mode is 1 and the correction coefficient k for the high-density mode is 1.5, the CPU 501 calculates Hu ₀ =Wt ₀ ×1, Hu ₁ =Wt ₁ ×1.5. Hu ₀ and Hu ₁ are calculated.
Then, using the calculated Hu ₀ and Hu ₁ , the CPU 501 calculates the total travel distance Ht by the arithmetic expression Ht=Hu ₀ +Hu ₁ (S307), and the calculated total travel distance Ht becomes the travel distance threshold value Wth. is exceeded (S308). In S309 and S310, the CPU 501 writes the first total value _Wt0 and the second total value _Wt1 updated in S304 to the DT memory m2. The processing of other steps is the same as described with reference to FIG. 6, so detailed description thereof will be omitted here.

[Third Another Developing Cartridge Life Judgment Sequence]
Further, the flowchart described in FIG. 8 is changed, and the first total value _Wt0 and the second total value _Wt1 in the high-density mode are subtracted from the developing roller travelable distance TD as the initial value, and the life of the developing cartridge 200 is extended. You can judge. The form will be described in detail below with reference to the flow chart of FIG.
First, the processing from S401 to S406 in FIG. 9 is the same as the processing from S301 to S306 described with reference to FIG. 8, so detailed description thereof will be omitted. Next, in S407, the CPU 501 subtracts the first total value Wt- ₀ and the second total value Wt- ₁ from the developing roller travelable distance TD as the initial value to calculate the travelable distance Ht'.
Ht′=TD−(Hu ₀ +Hu ₁ )
Next, the CPU 501 determines whether the calculated possible travel distance Ht' is less than the travel distance threshold value Wth, and performs the same processing as in S309 and S310 in S409 and S410. The processing of other steps is the same as described with reference to FIG. 6, so detailed description thereof will be omitted here.

また、各モードの現像ローラ走行距離補正係数と、現像ローラ走行可能距離ＴＤとの関係についても同様である。

このように、各モードに対する現像ローラ走行距離補正係数及び現像ローラ走行距離閾値Ｗｔｈの組み合わせは様々な形態が想定されるが、何れでも同様の効果を得られる。即ち、現像ローラ４の同じ駆動量に対して、通常モードにおいて累加又は累減する駆動量情
報の大きさを、高濃度モードにおける累加又は累減する駆動量情報の大きさよりも大きくし、寿命判断値を更新できる。 [Modified example of how to use the correction coefficient k]
6 to 10, the developing roller travel distance correction coefficient in the normal mode is 1, and the developing roller travel distance correction coefficient in the high density mode is 1.5. However, the present invention is not limited to this. A different correction coefficient may be assigned to each mode as long as the ratio between the developing roller traveling distance correction coefficient value and the developing roller traveling distance threshold value Wth in each mode is maintained. Examples are shown in Tables 2 and 3 below.

The same applies to the relationship between the developing roller traveling distance correction coefficient in each mode and the developing roller travelable distance TD.

As described above, various combinations of the developing roller travel distance correction coefficient and the developing roller travel distance threshold value Wth for each mode are assumed, but similar effects can be obtained in any of them. That is, with respect to the same amount of driving of the developing roller 4, the magnitude of information on the amount of driving that accumulates or decreases in the normal mode is made larger than the amount of information on the amount of driving that accumulates or decreases in the high-density mode, and the service life is determined. You can update the value.

As described above, when the developing roller traveling distance correction coefficient k is 1, reading of the correction coefficient by the CPU 501 may be skipped. CPU 501 needs to read the correction factor. That is, the CPU 501 may use a correction coefficient only for the travel distance Wu measured in the normal mode or the high density mode, depending on what kind of correction coefficient is assigned to each mode, or use the correction coefficient only for the travel distance Wu measured in each mode. A correction factor is used for both. In addition, in the case of FIGS. 8 and 9, the correction coefficient is used only for the first total value _Wt0 or the second total value _Wt1 , or the first total value _Wt0 and the second total value accumulated in each mode are A correction factor may be used for both values _Wt1 . in this way,
In this embodiment, it is possible to appropriately determine the lifespan of the developing cartridge 200 by using various correction coefficients.

In this embodiment, the case where the developing roller running distance correction coefficient k is single has been described, but the present invention is not limited to this. For example, the developing roller running distance correction coefficient k may be changed according to the developing roller remaining life DP. That is, first, as shown in Table 4, the developing roller running distance correction coefficient k is classified into a plurality of correction coefficients (k1 to k3) according to the range of remaining life DP of the developing roller. Then, the CPU 501 can use a correction coefficient classified according to the developing roller remaining life DP as the developing roller running distance correction coefficient k. These multiple correction coefficients are stored, for example, in the DT memory m2 and read by the CPU 501 as appropriate.

The correction coefficients classified according to the developing roller remaining life DP in Table 4 may be applied only to the normal mode or the high density mode, or may be applied to both modes. Also, in Table 4, the case where the developing roller running distance correction coefficient k is changed according to the remaining life DP of the developing roller 4 has been described, but the present invention is not limited to this. It may be changed according to the remaining toner amount TP, or the remaining life DP of the developing roller 4 and the remaining toner amount TP may be used together. It suffices if the developing roller correction coefficient k is properly determined in accordance with the change in parameters that contribute to the deterioration of the developing roller 4 used.

[Example 2]
In this embodiment, the correction coefficients are also stored in the O memory m1 mounted on the drum cartridge 210, and are determined together with the correction coefficients stored in the DT memory m2 mounted on the developing cartridge 200. It is. As shown in FIG. 11, the current flowing between the developing roller and the photosensitive drum varies depending on the thickness of the carrier transfer layer of the photosensitive drum. In other words, the life of the developing roller may vary depending on the state of the drum cartridge determined from the degree of consumption of the photosensitive drum. Therefore, in the O memory m1 mounted on the drum cartridge 210, a plurality of correction coefficients (second correction coefficients) classified according to the remaining life of the drum cartridge as shown in Table 5 are also stored. By determining the final developing roller travel distance correction coefficient k together with the developing roller travel distance correction coefficient described above, more accurate life information can be provided to the user.

[Developing Roller Life Calculation Sequence in this Embodiment]
A sequence for calculating the developing roller remaining life DP in this embodiment will be described. Note that descriptions of portions that overlap those of the first or second embodiment will be omitted. The remaining life of the drum cartridge is determined from the number of revolutions of the photosensitive drum 1, the film thickness of the carrier transfer layer of the photosensitive drum 1 in the initial state stored in the O memory m1, the scraping speed of the carrier transfer layer, and the like. It is obtained using the degree of consumption. Using the tables of Tables 4 and 5, the post-correction developing roller travel distance Hu is a predetermined developing roller travel distance Wu, the developing roller travel distance correction coefficient kn stored in the DT memory m2, and the developing roller travel distance correction coefficient kn stored in the O memory m1. It is obtained by multiplying the stored developing roller traveling distance correction coefficient on. The same applies to the corrected developing roller running distances Hu ₀ and Hu ₁ described in FIGS. 8 and 9 .
Hu=Wu×kn×on (n=1, 2, 3)
For example, when the remaining life of the developing cartridge is 80% and the remaining life of the drum cartridge is 20%, the developing roller correction coefficient k is k=k1×o3=1.5×1.2=1.8.
In this manner, by taking into account the driving history of the developing roller, it is possible to more appropriately determine the life of the developing cartridge 200 .

[Example 3]
In this embodiment, in printing in the high-density mode, a case will be described in which the rotation peripheral speed ratio between the photosensitive drum 1 and the developing roller 4 is changed by the image forming section. Specifically, the following settings were made by setting the potential setting and the rotation peripheral speed ratio as shown in Table 6. That is, the image forming units for yellow (Y), magenta (M), and cyan (C) achieve high density and wide color gamut, while black (K), which is mainly used for text printing, has high density and wide color gamut. This is a setting that suppresses the deterioration of the developing roller 4, rather than a setting that reduces the deterioration of the developing roller 4. FIG. As a result, when it is not necessary to set a high rotation peripheral speed ratio between the photosensitive drum 1 and the developing roller 4 according to how the developing cartridge 200 of each image forming section is used, the developing roller 4 is not used unnecessarily. Since deterioration does not occur, the number of exchanges of the developing cartridge 200 can be reduced.

Specifically, the potential setting and the rotation peripheral speed ratio were set as shown in Table 6. At this time, the peripheral speed of rotation of the photosensitive drum 1 was set to 100 mm/sec. This is to ensure that the rotation peripheral speed ratio between the intermediate transfer belt 31 and the photosensitive drum 1 is the same for yellow (Y), magenta (M), cyan (C) and black (K). Then, the peripheral speed of rotation of the yellow (Y), magenta (M), and cyan (C) developing rollers 4 is set to 250 mm/sec, and the peripheral speed of the developing roller 4 of black (K) is set to 1400 mm/sec. is set to

The difference in the post-correction developing roller travel distance HTn for yellow (Y), magenta (M), cyan (C), and black (K) will be described with reference to FIG. FIG. 11A is a diagram showing the amount of toner with respect to the number of printed sheets. Since the amount of black (K) used by users is large, the amount of toner contained in the developing cartridge 200 at the time of shipment is larger than that of yellow (Y), magenta (M), and cyan (C). FIG. 12B is obtained by converting FIG. 12A to the developing roller remaining life DP on the horizontal axis and the toner remaining amount TP on the vertical axis. The toner remaining amount TP is calculated according to each toner amount. FIG. 12(c) shows a state after correction is performed from FIG. 12(b) using the developing roller traveling distance correction coefficient k. Corrections for yellow (Y), magenta (M), and cyan (C) were performed as described in the first embodiment. However, since black (K) does not change the peripheral speed ratio between the developing roller 4 and the photosensitive drum 1 even in the high-density mode, it is not corrected (developing roller running distance correction coefficient k=1). made it As a result, when the high-density mode is selected, in the image forming section that does not change the rotation peripheral speed ratio between the photosensitive drum 1 and the developing roller 4, the running distance of the developing roller is not corrected unnecessarily. It was possible to report the lifespan of

DESCRIPTION OF SYMBOLS 100... Image forming apparatus 200... Developing cartridge (developing apparatus) 1... Photoconductive drum 4... Developing roller 303... Developing roller running distance calculation part 300... Control part

Claims (11)

a rotatable image carrier;
a developing device having a developer carrier that supplies a developer to the image carrier and develops an electrostatic latent image on the image carrier;
A first mode in which the developer carrier rotates with respect to the image carrier at a first peripheral speed ratio, and a second mode in which the developer carrier rotates with respect to the image carrier at a ratio greater than the first peripheral speed ratio. and a second mode rotating at a peripheral speed ratio of 2, wherein
storage means for storing a first correction coefficient corresponding to a rotation peripheral speed ratio between the image carrier and the developer carrier and a life threshold value of the developing device;
Based on first driving amount information when the developer bearing member operates in the first mode and second driving amount information when the developer bearing member operates in the second mode, the developing a control means for accumulating or decrementing the driving amount information of the developer bearing member with respect to the life judgment value of the apparatus, and updating the life judgment value;
The control means reads out the first correction coefficient stored in the storage means and uses it for the first drive amount information and/or the second drive amount information, so that the same driving of the developer carrier is performed. With respect to the amount, the magnitude of the driving amount information that is accumulated or progressively decreased by the second driving amount information is made larger than the magnitude of the driving amount information that is accumulated or gradually decreased by the first driving amount information, and the life An image forming apparatus characterized by updating a judgment value. a rotatable image carrier;
a developing device having a developer carrier that supplies a developer to the image carrier and develops an electrostatic latent image on the image carrier;
A first mode in which the developer carrier rotates with respect to the image carrier at a first peripheral speed ratio, and a second mode in which the developer carrier rotates with respect to the image carrier at a ratio greater than the first peripheral speed ratio. and a second mode rotating at a peripheral speed ratio of 2, wherein
storage means for storing a first correction coefficient corresponding to a rotation peripheral speed ratio between the image carrier and the developer carrier and a life threshold value of the developing device;
A first total value of drive amount information obtained by accumulating first drive amount information when the developer carrier operates in the first mode, and a second total value when the developer carrier operates in the second mode. a control means for accumulating a second total value of the driving amount information;
The control means is
Read out the first correction factor, use it for the first sum value and/or the second sum value, and determine life by summing based on the first sum value and the second sum value or subtracting from an initial value Calculate the value of
Image formation, wherein the magnitude of the sum or the subtraction based on the second total value is larger than the magnitude of the sum or the subtraction based on the first total value in the same driving amount of the developer carrier. Device. 3. An image according to claim 1, wherein said control means compares said lifespan judgment value with said lifespan threshold value and judges whether said lifespan judgment value exceeds or falls below said lifespan threshold value. forming device. a remaining amount acquisition unit that acquires the amount of developer contained in the developer container to be supplied to the developer carrier,
The control means determines that the developing device has reached the end of its life when the residual amount of the developer is small even when the life judgment value does not exceed the life threshold. The image forming apparatus according to claim 3. The image forming apparatus according to any one of claims 1 to 4, wherein the control means determines the life of the developing device based on the life judgment value and the life threshold. 6. The image forming apparatus according to claim 1, wherein the first correction coefficient includes a plurality of correction coefficients corresponding to remaining life of the developer carrier. 7. The image forming apparatus according to claim 6 , wherein the smaller the remaining life of said developer carrying member, the larger said first correction coefficient is assigned. 2. The control means further corrects the driving amount information of the developer carrier corrected by the first correction coefficient by a second correction coefficient corresponding to the degree of wear of the image carrier. 8. The image forming apparatus according to any one of 1 to 7 . 9. The image forming apparatus according to claim 8 , wherein the second correction coefficient increases as the remaining life of the image carrier provided in a cartridge detachable from the image forming apparatus decreases. 10. The image forming apparatus according to claim 9 , wherein the second correction coefficient is stored in storage means provided in the cartridge. 11. The image forming apparatus according to any one of claims 1 to 10 , further comprising informing means for informing about the life of said developing device.

Images