JP2020106744A - Image formation device - Google Patents

Abstract

To properly determine a product life of a development device even in an image formation device having a plurality of image formation modes different in a revolving circumferential velocity ratio between a photosensitive drum and a development roller.SOLUTION: In an image formation device having a first mode and a second mode different in respective revolving circumferential velocities of an image carrier and a developer carrier, the image formation device has: storage means that stores a first correction coefficient in response to the revolving circumferential velocity and a product life threshold of a development device; and control means that accumulatedly adds or accumulatedly reduces drive-amount information on the developer carrier with respect to a product life determination value of the development device on the basis of first drive-amount information when the developer carrier operates in the first mode and second drive-amount information when the developer carrier operates in the second mode. The control means is configured to, by using the first correction coefficient with respect to the first drive-amount information and/or the second drive-amount information, make the drive-amount information to be accumulatedly added or accumulatedly reduced by the second drive-amount information greater than the drive-amount information to be accumulatedly added or accumulatedly reduced by the first drive-amount information with respect to the same drive-amount information on the developer carrier, and renews the product life determination value.SELECTED DRAWING: Figure 6

Description

The present invention relates to a technique for determining the life of a developing device provided in an image forming apparatus such as a copying machine, a printer, and a facsimile, which uses an electrophotographic method, an electrostatic recording method, or the like.

In an image forming apparatus such as a printer using an electrophotographic image forming method (electrophotographic process), an electrophotographic photosensitive member (hereinafter referred to as “photosensitive member”) as an image carrier is uniformly charged, and the charged photosensitive member is charged. An electrostatic image is formed on the photoreceptor by selectively exposing the body. The electrostatic image formed on the photoconductor is visualized as a toner image with toner as a developer. Then, the toner image formed on the photoconductor is transferred to a recording material such as recording paper or a plastic sheet, and heat or pressure is applied to the toner image transferred onto the recording material to form the toner image on the recording material. An image is formed by fixing.
Such an image forming apparatus generally requires replenishment of the developer and maintenance of various process means. In order to facilitate the developer replenishment work and the maintenance of various process means, a process in which the photoconductor, the charging means, the developing means, the cleaning means and the like are collectively made into a cartridge and can be attached to and detached from the image forming apparatus main body. It has been put to practical use as a cartridge. According to the process cartridge system, it is possible to provide an image forming apparatus having excellent usability.
In such a process cartridge, as the number of times an image is formed increases, toner that is repeatedly collected without being developed on a photosensitive drum, which is an example of a photosensitive member, is generated. Such a toner may be deteriorated due to the fact that the toner image formation is repeated many times, so that the external additive that is added is released from or embedded in the resin particles that are the base of the toner. There is. In such a case, the toner may not be able to obtain a desired charge amount, and so-called fogging or the like may occur in which the toner adheres to a white background portion on the image. In view of this, Japanese Patent Application Laid-Open No. 2004-242242 proposes a method in which the degree of deterioration of toner in the image forming apparatus is calculated and integrated to determine that the developing apparatus has reached the end of its life. Further, in Japanese Patent Laid-Open No. 2004-242242, a more optimal 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 are deposited on the developing roller. Proposed.

Japanese Patent No. 4743273 JP, 2016-161645, A

In recent years, one of a wide variety of market demands has been made to increase the image density and expand the color tone for the purpose of obtaining a richer image. The following techniques are known for achieving the purpose. First, in addition to an image forming mode for obtaining a general image density, an image forming mode for changing the peripheral speed ratio between the photosensitive drum and the developing roller is provided as a means for realizing high density and an increase in tint. .. 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, so that the density of the image is increased and the tint is increased.
It has been found by the study by the inventor that if the peripheral speed ratio between the photosensitive drum and the developing roller is increased by using this technique for printing, the deterioration of the developing roller is affected. If the developing roller deteriorates early, the volume resistance value increases, and the electric charge of the toner on the developing roller does not easily escape to the developing roller, and the toner accumulates the electric charge. As a result, for example, the electric charge of the toner on the developing roller becomes excessive, and the regulation by the regulation member becomes insufficient, so-called regulation failure occurs at an early timing. That is, 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 a problem. 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 device capable of selecting an image forming mode in which the rotation peripheral speed ratio of a photosensitive drum and a developing roller is changed.

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 for supplying a developer to the image carrier to develop the electrostatic latent image on the image carrier,
A first mode in which the developer bearing member rotates at a first peripheral speed ratio with respect to the image bearing member, and a first mode in which the developer bearing member has a larger peripheral speed ratio with respect to the image bearing member. An image forming apparatus having a second mode of rotating at a peripheral speed ratio of 2,
Storage means for storing a first correction coefficient according to a rotational peripheral speed ratio between the image carrier and the developer carrier, and a life threshold of the developing device;
The development based on first drive amount information when the developer carrier operates in the first mode and second drive amount information when the developer carrier operates in the second mode. Control means for cumulatively adding or subtracting the driving amount information of the developer carrier with respect to the life judgment value of the apparatus, and updating the life judgment value,
The control unit reads the first correction coefficient stored in the storage unit and uses the first correction coefficient for the first drive amount information and/or the second drive amount information so that the same drive of the developer carrying member is performed. With respect to the amount, the size of the drive amount information that is cumulatively added or reduced by the second drive amount information is made larger than the size of the drive amount information that is cumulatively added or reduced by the first drive amount information, and the life is increased. The feature is that the judgment value is updated.
Further, in order to achieve the above object, the image forming apparatus of the present invention,
A rotatable image carrier,
A developing device having a developer carrier for supplying a developer to the image carrier to develop the electrostatic latent image on the image carrier,
A first mode in which the developer bearing member rotates at a first peripheral speed ratio with respect to the image bearing member, and a first mode in which the developer bearing member has a larger peripheral speed ratio with respect to the image bearing member. An image forming apparatus having a second mode of rotating at a peripheral speed ratio of 2,
Storage means for storing a first correction coefficient according to a rotational 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 cumulatively adding 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. Control means for cumulatively adding a second total value of driving amount information obtained by cumulatively adding driving amount information,
The control means is
The first correction coefficient is read and used for the first total value and/or the second total value, and the life is judged by the sum based on the first total value and the second total value or by subtracting from the initial value. Calculate the value,
It is characterized in that, in the same drive amount of the developer carrying member, the sum or the subtraction amount by the second sum value is larger than the sum or the subtraction amount by the first sum value.

According to the present invention, even in an image forming apparatus having a plurality of image forming modes in which the rotation peripheral speed ratio between the photosensitive drum and the developing roller is different, the life of the developing apparatus can be appropriately determined.

Schematic of image forming device Schematic of drum cartridge Schematic of developer cartridge Hardware block diagram of image forming apparatus A graph showing the relationship between the rotational peripheral speed ratio and the current value between the photosensitive drum and the developing roller. Development cartridge life judgment sequence chart Life judgment sequence chart of another developer cartridge Life judgment sequence chart of another developer cartridge Life judgment sequence chart of another developer cartridge Example of change in remaining life of developing cartridge Film thickness of carrier transfer layer of photosensitive drum and current value flowing between developing rollers Example of change in remaining life of developing cartridge in Embodiment 3

MODES FOR CARRYING OUT THE INVENTION Modes for carrying out the present invention will be exemplarily described in detail below based on embodiments with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in this embodiment should be appropriately changed depending on the configuration of the apparatus to which the invention is applied and various conditions. That is, the scope of the present invention is not intended to be limited to the following embodiments.

[Example 1]
An overall configuration of an embodiment of the electrophotographic image forming apparatus (image forming apparatus) will be described. FIG. 1 is a sectional view of the image forming apparatus 100 of this embodiment. The image forming apparatus 100 according to the present exemplary 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 the image information. The image information is input to the image forming apparatus main body from an image reading apparatus connected to the image forming apparatus main body or a host device such as a personal computer communicatively connected to the image forming apparatus main body. The image forming apparatus 100 includes SY, SM, SC, and SK for forming images of respective colors of yellow (Y), magenta (M), cyan (C), and black (K) as a plurality of image forming units. Have. In this embodiment, the image forming units SY, SM, SC, SK are arranged in a line in a direction intersecting the vertical direction.

The image forming apparatus 100 according to the present exemplary embodiment includes the photosensitive drum 1, the charging roller 2, the cleaning blade 6, and the drum cartridge frame 11 shown in FIG. The drum cartridge 210 is configured. Further, 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 accommodating chamber 20b shown in FIG. The developing cartridge 200 is used.
The above-described image forming unit includes the drum cartridge 210 (210Y, 210M, 210C, 210K) and the developing cartridge 200 (200Y, 200M, 200C, 200K). The drum cartridge 210 and the developing cartridge 200 can be attached to and detached from the image forming apparatus 100 via an attaching means such as an attaching guide and a positioning member provided in the image forming apparatus main body. In this embodiment, the drum cartridge 210 for each color and the developing cartridge 200 have the same shape, and the developing cartridge 200 for each color has yellow (Y), magenta (M), and cyan (C), respectively. , And black (K) toners are stored. In this embodiment, the configuration in which the drum cartridge 210 and the developing cartridge 200 are independently attachable/detachable is described, but the configuration in which the drum cartridge 210 and the developing cartridge 200 are integrally attachable/detachable to/from the image forming apparatus main body may be employed.

The photosensitive drum 1 is rotationally driven by a driving unit (driving source) not shown. A scanner unit (exposure device) 30 is arranged around the photosensitive drum 1. The scanner unit 30 is an exposure unit that irradiates a laser based on image information to form an electrostatic image (electrostatic latent image) on the photosensitive drum 1. In the main scanning direction (the direction orthogonal to the conveying direction of the recording material 12), the writing of the laser exposure is performed for each scanning line from a position signal in the polygon scanner called BD. On the other hand, in the sub-scanning direction (conveying direction of the recording material 12), the recording is performed with a delay of a predetermined time from the TOP signal originating from a switch (not shown) in the recording material 12 conveying path. As a result, the laser exposure can always be performed at the same position on the photosensitive drum 1 in the four process stations Y, M, C, and K.

An intermediate transfer belt 31 as an intermediate transfer member for transferring the toner image on the photosensitive drums 1 to the recording material 12 is arranged facing the four photosensitive drums 1. The intermediate transfer belt 31 formed of an endless belt as an intermediate transfer member contacts all the photosensitive drums 1 and circulates (rotates) in the direction of arrow B (counterclockwise) in the drawing. On the inner peripheral surface side of the intermediate transfer belt 31, four primary transfer rollers 32 as primary transfer means are arranged in parallel so as to face the photosensitive drums 1. Then, a bias having a polarity opposite to the regular charging polarity of the toner is applied to the primary transfer roller 32 from a primary transfer bias power source (high voltage power source) as a primary transfer bias applying unit (not shown). 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. Then, a bias having a polarity opposite to the regular charging polarity of the toner is applied to the secondary transfer roller 33 from a secondary transfer bias power source (high voltage power source) as a secondary transfer bias applying unit (not shown). As a result, the toner image on the intermediate transfer belt 31 is transferred (secondary transfer) to the recording material 12. For example, when forming a full-color image, the above-described process is sequentially performed in the image forming units SY, SM, SC, and SK, and the toner images of the respective colors are sequentially superposed and primarily transferred onto the intermediate transfer belt 31. Thereafter, the recording material 12 is conveyed to the secondary transfer portion in synchronization with the movement of the intermediate transfer belt 31. Then, the four-color toner images on the intermediate transfer belt 31 are collectively secondarily 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. It

The recording material 12 to which the toner image is transferred is conveyed to the fixing device 34 as a fixing unit. By applying heat and pressure to the recording material 12 in the fixing device 34, the toner image is fixed on the recording material 12.

[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 view (main cross-sectional view) of the drum cartridge 210 of the present embodiment as seen along the longitudinal direction (rotational axis direction) of the photosensitive drum 1.
The photosensitive drum 1 is rotatably attached to the drum cartridge 210 via a bearing (not shown). The photosensitive drum 1 is rotationally driven in the direction of arrow A in the figure according to an image forming operation by receiving the driving force of a driving motor as a photosensitive drum driving unit (driving source A).

The photosensitive drum 1 uses an organic photosensitive member in which an underlayer, a high resistance layer, a carrier layer, and a carrier transfer layer, which are functional films, are sequentially coated on the outer peripheral surface of an aluminum cylinder having a diameter of 30 mm. Since the carrier transfer layer is scraped and consumed by the image forming operation, it is necessary to form a film thickness according to the life of the drum cartridge 210. In order to achieve a long service life in response to recent market demand, the thickness is set to 25 μm in this embodiment.

Further, in the drum cartridge 210, the cleaning blade 6 formed of an elastic body and the charging roller 2 is arranged so as to contact the peripheral surface of the photosensitive drum 1. Further, a drum cartridge frame 11 having a storage space for storing the toner on the photosensitive drum 1 removed by the cleaning blade 6 is provided. The charging roller 2 is applied with a sufficient bias so that an arbitrary charge can be placed on the photosensitive drum 1 from a charging bias power source (high voltage power source) as a charging bias applying unit (not shown). In this embodiment, the applied bias is set so that the potential (charging potential: Vd) on the photosensitive drum 1 becomes −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 of the laser 35, the electric charge on the surface of the photosensitive drum 1 disappears due to the carriers from the carrier generation layer, and the electric potential of the irradiation portion decreases. As a result, the irradiated portion of the laser 35 forms an electrostatic latent image having 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 an O memory m1) which is a storage unit. The O memory m1 stores information such as the number of rotations of the photosensitive drum 1 and the manufacturing number, and the usage amount 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 capable of communicating (writing and reading of information) with the control unit 300 of the image forming apparatus 100 shown in FIG. 1 by non-contact or by contact via an electric contact (not shown).

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

The developing cartridge 200 includes a developing chamber 20a, a developer accommodating chamber 20b, a developing roller 4, a toner supply roller 5, and a developer container 22 that constitutes the developing chamber 20a and a developer accommodating chamber 20b. The developer accommodating chamber 20b is arranged below the developing chamber 20a. The toner 9 as a developer is stored in the developer storage chamber 20b. In the present embodiment, the normal charge polarity of the toner 9 is negative, and the case of using a negative charge toner will be described below. However, the present invention is not limited to the negatively chargeable toner.

Further, in the developer accommodating chamber 20b, a developer conveying member 21 for conveying the toner 9 to the developing chamber 20a is provided, and by rotating in the direction of arrow G in the figure, the toner 9 is transferred to the developing chamber 20a. Is being transported to. The developer carrying member 21 is composed of an elastic sheet-shaped member extending in the longitudinal direction of the cartridge.

In the developing chamber 20a, a developing roller 4 as a developer bearing member that comes into contact with the corresponding photosensitive drum 1 and rotates in the direction of arrow D in the drawing by receiving the driving force of a driving motor as a developing driving unit (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 cored bar. Then, a sufficient bias for developing and visualizing the electrostatic latent image on the photosensitive drum 1 as a toner image is applied from a developing bias power source (high voltage power source) as a developing bias applying unit (not shown).

Further, inside the developing chamber 20 a, a toner supply roller (hereinafter, simply referred to as “supply roller”) 5 that supplies the toner conveyed from the developer accommodating chamber 20 b to the developing roller 4, and a supply roller 5 supply the toner. A toner amount regulating member (hereinafter, simply referred to as “regulating member”) 8 that regulates the amount of toner coated on the developing roller 4 and imparts electric charge is arranged.

Further, the developing cartridge 200 is provided with a non-volatile memory (hereinafter, DT memory m2) which is a storage unit. The DT memory m2 stores the total driving amount of the developing roller 4, the remaining toner amount, 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 control unit 300 of the image forming apparatus 100 in a non-contact manner or a 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 a normal mode). In the second mode, the rotation peripheral speed ratio between the photosensitive drum 1 as the image bearing member and the developing roller 5 as the developer bearing member is increased while lowering the dark portion potential on the image bearing member to select high density and tint. An image forming mode (hereinafter, referred to as a high density mode) for increasing the range.
Table 1 below shows specific differences in control between the normal mode and the high-concentration 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 portion 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. The bright portion potential Vl is the potential of the surface of the photosensitive drum 1 after being irradiated with the laser 35. The developing potential Vdc is a potential applied to the developing roller 4 by the developing bias power source.

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

As shown in Table 1, the difference between the developing potential Vdc and the bright portion potential Vl (hereinafter, referred to as developing contrast) is set to be larger in the high density mode than in the normal mode. As a result, the amount of toner developed on the photosensitive drum 1 among the toner coated on the developing roller 4 is larger 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 is increased. Due to these two effects, the amount of toner on the recording material 12 can be increased, and an image with high density and high color gamut can be printed.

[Toner level detection method]
Here, the toner remaining amount detecting method by the video counting method used in the present 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. The CPU 501 is also provided that also plays the role of. Further, a memory 502 and the like on the apparatus main body side, which stores information necessary for controlling the motor drive unit 511 and the high-voltage power supply 512, are also provided. Further, the information stored in the O memory m1 of the drum cartridge 210 or the DT memory m2 of the developing cartridge 200 is input/output to/from the CPU 501 from the input/output I/F 503 via the memory communication unit 500 and exchanged with the control unit 300. Is going. Further, the control unit 300 is connected to a video count measuring unit 305 that measures a video signal output by the image forming operation.
The principle of toner remaining amount detection using video count will be described. Another control device (not shown) is arranged upstream of the control unit 300, and a laser drive signal (video signal) from the control device is branched to form a video during a period in which an electrostatic latent image is formed on the photosensitive drum. Sample the signal. The sampled video signal is input to a hardware counter in the control unit 300 to count the number of ON of the video signal ON/OFF, and the CPU 501 reads the value. The read value indicates the amount of toner consumed, and the value obtained by subtracting the count value from the predetermined initial value is used as information indicating the remaining amount of toner. Then, when the number of ONs of the video signal is divided by the number of ONs measured when a black image is printed on the area on the recording material where the image is to be printed, which is calculated to form an electrostatic latent image. Only the ratio of whether the laser is turned on can be obtained. The electrostatic latent image is formed on the portion irradiated with the laser, and the toner adheres to the portion. Therefore, the remaining toner amount can be calculated based on the lighting ratio of the laser. Note that the count by the video count measurement unit 305 specifically corresponds to the count of ON video signals for irradiating a laser beam, but the sampling period may not be synchronized with the video clock of the video signal. If sampling is performed at a cycle shorter than the video clock, the video count measuring 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.

The video count measuring unit 305 measures pixel information (video count value VCn) of the output image. In the present embodiment, one output of the recording material 12 is set as one video count value VCn. The CPU 501 calculates the remaining toner amount according to the following procedure. First, the video count value VCn measured by the video count measuring unit 305 is added to the cumulative video count value VCr stored in the DT memory m2 of the development cartridge 200 from the start of use of the development cartridge 200 to obtain the total video count value VCt. To 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)×100
Then, the CPU 501 writes the total video count value VCt as the cumulative video count value VCr in the DT memory m2.
Here, when the toner remaining amount TP=100%, the toner 9 in the developing cartridge 200 is in a full state, which means that the developing cartridge 200 is new. Further, when the remaining toner amount TP=0%, the remaining amount of the toner 9 in the developing cartridge 200 almost disappears, which indicates that the developing cartridge 200 is at the replacement timing.
In the present embodiment, the video count threshold value VCth at which the remaining toner amount TP=0% indicates that the toner supply from the supply roller 5 to the developing roller 4 is insufficient even when a high print image such as a solid image is printed. It was set based on the remaining amount of toner 9 which is not present. Therefore, the actual remaining toner amount may be TP=5%, for example.

[Development roller life calculation method]
Next, a method of calculating the life of the developing roller 4 will be described. The life of the developing roller 4 is determined according to the traveling distance Wu of the developing roller 4. In the following description, the travel distance Wu will be described as an example of drive amount information indicating how much the developing roller 4 has driven. However, the drive amount information may indicate how much the developing roller 4 has driven. , Various parameters can be used. For example, it may be the total drive time of the developing cartridge 200 or the total number of rotations of the developing roller 4. Alternatively, it may be the number of printed sheets formed using the developing cartridge 200.
The image forming apparatus 100 includes a developing roller running distance measuring unit 302 that measures the running distance Wu of the developing roller 4, and the CPU 501 measures the developing roller running distance Wu of the developing roller 4 using the developing roller running distance correction coefficient k. The traveling distance Wu is corrected.

The developing roller running distance measuring unit 302 measures the running 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×Ps×Sr
Here, the traveling distance Wu represents how much a certain point on the surface of the developing roller 4 has advanced by the rotation of the developing roller 4. 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 travel 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 rotational 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 set to k=1 in the normal mode and k=1.5 in the high density mode.
Then, the CPU 501, as a correction distance acquisition unit, multiplies a predetermined developing roller running distance Wu by a developing roller running distance correction coefficient k to calculate a corrected developing roller running distance Hu.
Hu=Wu×k

Next, the corrected developing roller running distance Hu is cumulatively added to the cumulative developing roller running distance HT _n−1 from the start of use of the developing cartridge 200 stored in the DT memory m2. By doing so, the total corrected developing roller traveling distance HT _n (n=1, 2... N, HT ₀ =0), that is, the latest cumulative developing roller traveling distance HT _n is calculated. To do.
HT _n =HT _n-1 +Hu

Then, from the developing roller running distance threshold value Wth stored in the DT memory m2 and the latest cumulative developing roller running distance HT _n , the developing roller remaining life DP is calculated by the following formula.
DP [%]=(1-HT _n /Wth)×100
The developing roller travel distance threshold value Wth corresponds to the life threshold value regarding the life of the developing roller.

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

In the present embodiment, the developing roller travel distance threshold value Wth is set based on the developing roller travel distance at which so-called regulation failure occurs in which the toner coating amount on the developing roller 4 is not sufficiently regulated by the regulation member 8.

Here, the relationship between the developing roller travel distance and the regulation failure 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 (current 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 regulation force of the regulation member 8, the regulation cannot be sufficiently performed, resulting in defective regulation.
The energization deterioration varies 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 value flowing through the developing roller increases as the rotation peripheral speed ratio increases, as shown in FIG. That is, the energization deterioration progresses as the rotation peripheral speed ratio increases. If there are modes with different rotational peripheral speed ratios, it is necessary to correct them. The susceptibility to deterioration due to energization changes depending on the characteristics of the developing roller. Since the specifications of the developing roller may change, it is preferable to store the correction coefficient in the DT memory m2 mounted on the developing cartridge 200. However, the present invention 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 determining the life of the developing cartridge 200 in the first embodiment. Based on the information of the DT memory m2 mounted on the developing cartridge 200, the CPU 501 incorporated in the control unit 300 performs the process shown in the flowchart of FIG. 6 as a life determining unit to determine the life of the developing cartridge 200, and Notify the user of the result.

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 the setting information included in the print data is set to "0", for example, and the high density mode if the setting information is set to "1", and executes the subsequent processing. (S102).

Next, the CPU 501 starts the image forming operation of the image forming apparatus 100 including the developing cartridge 200 (S103). The image forming operation here includes the charging potential of the charging roller 2, the developing potential setting of the developing roller 4, 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. , Including all operations required for image formation. It should be noted that when the driving of the developing roller 4 is started, the traveling distance Wu is measured by the CPU 501, and such measurement processing is also included in the image forming operation here. Then, the traveling distance Wu measured when the normal mode is selected in S101 corresponds to the first drive amount information of the first mode, and the traveling distance Wu measured when the high concentration mode is selected is the second. This corresponds to the second drive 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 it is the normal mode. Note that when the correction coefficient of the selected image forming mode is 1, it is not necessary to perform correction, and thus the processing of S102 may be skipped by the CPU 501.

Next, the CPU 501 calculates the corrected developing roller traveling distance Hu using the read developing roller traveling distance correction coefficient k (S105). The timing at which the CPU 501 calculates the corrected developing roller travel distance Hu may be after the printing is completed or at a predetermined interval. In either case, the calculation target is the uncalculated developing roller travel distance Wu.

Then, the CPU 501 runs the corrected developing roller running distance Hu and the latest cumulative developing roller running distance HT _n-1 stored in the DT memory m2 from the latest cumulative developing roller running distance as a life judgment value. The distance HT _n is calculated (S106).
Then, CPU 501 compares the latest cumulative after development roller running distance HT _n and the travel distance threshold Wth, the latest cumulative after development roller running distance HT _n determines whether exceeds a mileage threshold Wth (S107). Then, if HT _n exceeds Wth, the CPU 501 writes the latest cumulative post-correction developing roller traveling distance HT _n , which is the above-described total corrected developing roller traveling distance, in the DT memory m2 (S109). After that, the notification means is used to notify the user that the developing cartridge 200 has reached the end of its life through the external I/F 504 (S110). The notification means may be a body display means such as a monitor, a voice speaker, or the like, 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, when the latest cumulative post-accumulation developing roller travel distance HT _n, which is the total corrected developing roller travel distance, does not exceed the travel distance threshold Wth, the CPU 501 sets the latest cumulative post-accumulation developing roller travel distance HT _n . 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 the post-correction developing roller travel distance HT _n exceeds the travel distance threshold Wth, but the invention is not limited to this. That is, the remaining life DP of the developing roller may be obtained by the CPU 501 in S106 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-HT _n /Wth)×100
The method using the remaining life DP of the developing roller is the same in FIG. 8 described later.

On the other hand, after the CPU 501 receives the image information based on the print data (S111), the video count measuring unit 305 measures the video count value VC to calculate 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 small, that is, whether the remaining toner amount TP is 0% or less (whether or not it is less than or equal to a predetermined threshold remaining amount). (S114). If the toner remaining amount TP reaches 0% or less, the CPU 501 writes the cumulative video count value VCr in 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, when the toner remaining amount TP has not reached 0% or less, the CPU 501 writes the cumulative video count value VCr in the DT memory m2 (S115), and the image forming apparatus 100 prepares for the next image formation. To do.

The calculation of the toner remaining amount TP has been described as the method of determining whether or not the toner remaining amount is low, but the method is not limited to this. For example, since the total video count value VCt indicates the toner consumption amount itself, the CPU 501 determines whether or not the total video count value Vct exceeds a predetermined threshold value, and determines whether or not the toner remaining amount is low. Is also good. Further, although the toner remaining amount detecting method by the video counting method has been described as an example, the present invention is not limited to this. For example, a remaining amount detection method based on capacitance or a light transmission remaining amount detection method may be used, or may be used in combination with these. Specifically, when the remaining amount of toner acquired by the video count method is less than or equal to a predetermined remaining amount, either the electrostatic capacity method or the light transmission method may be used. That is, a more suitable remaining amount acquisition method may be selected according to the degree of the remaining amount of toner. Note that the electrostatic capacitance method uses an electrode whose electrostatic capacitance that is detected according to a change in the state of the toner inside the developer accommodating chamber is used (for example, a conductive member is attached to the inner wall of the accommodating chamber) for detection. In this method, the amount of toner is acquired based on the change in the electrostatic capacity. This is a known method in the related art, and detailed description thereof will be omitted. Further, the light transmission method uses a light source for irradiating the interior of the developer accommodating chamber with a light and a light receiving unit for receiving the light passing through the accommodating chamber, and the toner is detected based on a change in the light receiving state of the light receiving unit. This is how to get the amount. This method is also a known method in the related art, and detailed description thereof will be omitted. The same applies to the flowcharts described below.

In the first embodiment that executes this series of flowcharts, the traveling distance Wu of the developing roller 4 is corrected by the developing roller traveling distance correction coefficient k according to the image forming mode selected by the user. By doing so, it becomes possible to properly judge the life of the developing cartridge 200 and notify the user. The detection result of the remaining amount of toner is also used to detect that the amount of toner in the developing cartridge 200 is almost exhausted. As a result, not only the life due to the deterioration of the developing roller 4 due to energization but also the life of the developing cartridge 200 due to the remaining amount of toner can be reported, and the life of the developing cartridge 200 can be more appropriately notified to the user.

Here, the difference between the total corrected developing roller travel distance HT _n between when the printing is performed in the normal mode and when the printing is performed in the high density mode will be described with reference to FIG. 10. FIG. 10A shows a case where a fixed pattern is printed in each of the normal mode and the high density mode. The horizontal axis represents the number of prints, and the vertical axis represents the remaining toner amount TP. Even when the same pattern is printed, the amount of toner used in the high density mode is larger and 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, defective regulation occurred due to deterioration of energization of the developing roller. This is the point indicated by point A. FIG. 10B shows the horizontal axis of FIG. 10A converted to the remaining life DP of the developing roller 4. 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%, that is, the image adverse effect occurs before the user is notified of the life. It shows that it has been done.

In FIG. 10C, the correction coefficient k=1 when printing in the normal mode, and the correction coefficient k=1.5 is applied to the life of the developing roller when printing in the high density mode to correct the life of the developing roller. It shows the case of performing. As a result, image defects such as poor regulation did not occur until the remaining life DP of the developing roller 4=0%. Therefore, by correcting the running distance W of the developing roller 4, it is possible to notify the life of the developing cartridge 200 before the adverse effect of the image such as the restriction failure due to the deterioration of the energization of the developing roller 4 occurs.

[First different development cartridge life judgment sequence]
In the description of FIG. 6, the corrected developing roller traveling distance Hu is cumulatively added to HT _n−1 corresponding to the previous total corrected developing roller traveling distance, and the latest accumulated developing roller traveling distance (total traveling distance) HT _{n is} calculated. The method of determining the life of the developing roller by determining However, it is not limited to this. For example, the corrected developing roller travel distance Hu is cumulatively reduced from the developing roller travelable distance TD (Total Distance) stored in the DT memory m2 as an initial value at the start of use of the developing cartridge 200. By doing so, the travelable distance HT′ _n as a life judgment value for judging the life of the developing roller may be calculated. Note that HT ₀ matches the developing roller travelable distance TD as an initial value.
Ht' _n =HT _n-1 -Hu
Then, the developing roller calculated 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) × 100

Hereinafter, the developing cartridge life determination sequence by the cumulative reduction process of the CPU 501 will be described in detail with reference to the flowchart of FIG. 7. First, since the processing of S201 to S205 of FIG. 7 is the same as the processing of S101 to S105 described in FIG. 6, detailed description thereof will be omitted. Next, the corrected developing roller travel distance Hu is gradually reduced from the initial value TD stored in the DT memory m2 or the previous travelable distance HT' _n-1 to calculate the latest travelable distance HT' _n (S206). ). Incidentally, the traveling distance HT _'n of the latest is equivalent to the lifetime determination value.
Then, CPU 501 is 'compares _n with mileage threshold Wth, latest DTE HT' latest DTE HT determines whether the _n falls below the mileage threshold Wth (S207). If the travelable distance HT′ _n is less than the travel distance threshold Wth as determined by the CPU 501 in S207, the CPU 501 writes the cumulative travelable distance HT′ _n in the DT memory m2 (S209). After that, the notification means is used to notify the user that the developing cartridge 200 has reached the end of its life through the external I/F 504 (S110).

On the other hand, when the latest travelable distance HT′ _n is not below the traveled distance threshold Wth, the CPU 501 writes the latest travelable distance HT′ _n in the DT memory m2 and updates (S108) the next image. Prepare for formation. Other processes are the same as those in the flowchart shown in FIG. 6, and 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 below the travel distance threshold Wth, but the invention is not limited to this. That is, the remaining life DP' of the developing roller may be obtained by the CPU 501 in S206 using the following formula, and the life of the developing roller may be determined by whether DP' is 0 or less than a predetermined value.
DP '[%] = (HT ' n / Wth) × 100
The method using the remaining life DP' of the developing roller is the same in FIG. 9 described later.
The frequency at which the processing of S205 to S207 is executed is not limited to a particular frequency. For example, the processing of S205 to S207 may be performed for the traveling distance Wu measured by the CPU 501 as needed every one second. Alternatively, each time the print job is completed, the processes of S205 to S207 may be performed on the traveling distance Wu measured from the start of the print job. Furthermore, the process of S205 may be performed every time a predetermined number of print jobs are completed. The same applies to S105 to S107 of FIG. 6 described above.

[Second development cartridge life judgment sequence]
In the description of FIGS. 6 and 7 above, whether the CPU 501 updates the post-accumulation developing roller traveling distance HT _n or the travelable distance HT′ _{n at} a predetermined frequency, and whether the developing cartridge 200 has reached the end of its life. It was explained to judge whether or not. However, the same effect can be obtained by another life judgment sequence.
For example, the total running distance Wt ₀ of the developing roller in the normal mode and the total running distance Wt ₁ of the developing roller in the high density mode are stored respectively, and the CPU 501 stores the developing cartridge 200 based on the stored Wt ₀ and Wt _1. You may judge the life of the. In the suffix of Wt, "0" means the normal mode and "1" means the high density mode. Hereinafter, the form will be described in detail with reference to the flowchart of FIG.

First, since the processing of S301 to S303 in FIG. 8 is the same as the processing of S101 to S103 described in FIG. 6, 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 traveling distance Wu measured in S303 (S304). For example, an image forming mode selected in S302, in the case of high concentration mode, a running distance Wu measured in S303, and added to the developing roller total distance Wt _1, CPU 301, the latest Wt ₀ and Wt _{Get 1} . Here, Wt ₀ is the first total value obtained by accumulating the first drive amount information that is the travel distance Wu measured in the normal mode, and Wt ₁ is the second drive amount information that is the travel distance Wu measured in the high concentration mode. Respectively corresponding to the second total value, which will be described below.

Next, the CPU 501 reads the developing roller running distance correction coefficient k corresponding to the image forming mode from the DT memory m2 (S305). Then, CPU 501 is amended development roller running distance Hu ₀ in the normal mode, and the amended development roller running distance Hu ₁ high concentration mode is calculated based on the developing roller running distance correction coefficient k read in S305, respectively (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 sets Hu ₀ =Wt ₀ ×1, Hu ₁ =Wt ₁ ×1.5. Calculate Hu ₀ and Hu ₁ .
Then, the CPU 501 uses the calculated Hu ₀ and Hu ₁ to calculate the total travel distance Ht by an arithmetic expression of Ht=Hu ₀ +Hu ₁ (S307), and the calculated total travel distance Ht is the travel distance threshold Wth. It is determined whether or not it exceeds (S308). In S309 and S310, the CPU 501 writes the first total value Wt ₀ and the second total value Wt ₁ updated in S304 into the DT memory m2. The processing of each of the other steps is the same as that described with reference to FIG. 6, and detailed description thereof is omitted here.

[Third Alternative Development Cartridge Lifetime Determination Sequence]
Further, by modifying the flow chart described in FIG. 8, the first total value Wt ₀ and the second total value Wt _{1 in} the high density mode are subtracted from the developing roller travelable distance TD as an initial value to determine the life of the developing cartridge 200. You may judge. Hereinafter, the form will be described in detail with reference to the flowchart of FIG.
First, the processing of S401 to S406 in FIG. 9 is the same as the processing of S301 to S306 described in FIG. 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 an initial value to calculate the travelable distance Ht′.
_{Ht '= TD- (Hu 0 +} Hu 1)
Next, the CPU 501 determines whether or not the calculated travelable distance Ht′ is below the traveled distance threshold Wth, and in S409 and S410, the same processing as S309 and S310 is performed. The processing of each of the other steps is the same as that described with reference to FIG. 6, and detailed description thereof is 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。 [Modification of Usage of Correction Coefficient k]
In the description of FIGS. 6 to 10, the development roller travel distance correction coefficient in the normal mode is 1, and the development roller travel distance correction coefficient in the high density mode is 1.5, but the invention is not limited to this. A different correction coefficient may be assigned to each mode as long as the relationship between the ratio of the development roller traveled distance correction coefficient value in each mode and the development roller traveled distance threshold value Wth is maintained. Hereinafter, examples are shown in Tables 2 and 3.

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

As described above, various combinations of the developing roller traveling distance correction coefficient and the developing roller traveling distance threshold value Wth are assumed for each mode, but the same effect can be obtained in any combination. That is, with respect to the same drive amount of the developing roller 4, the size of the drive amount information that is cumulatively added or reduced in the normal mode is made larger than the size of the drive amount information that is cumulatively added or reduced in the high density mode to determine the life. You can update the value.

As described above, when the developing roller travel distance correction coefficient k is 1, the reading of the correction coefficient by the CPU 501 may be skipped, but when a correction coefficient other than 1 is assigned. The CPU 501 needs to read the correction coefficient. That is, the CPU 501 uses the correction coefficient only for the traveling distance Wu measured in the normal mode or the high concentration mode, or the traveling distance Wu measured in each mode, depending on what correction coefficient is assigned to each mode. A correction coefficient is used for both. In the case of FIGS. 8 and 9, the correction coefficient is used only for the first total value Wt ₀ or the second total value Wt _1, or the first total value Wt ₀ and the second total value accumulated in each mode are added. A correction coefficient is used for both of the values Wt ₁ . in this way,
In this embodiment, the life of the developing cartridge 200 can be properly determined by using various correction coefficients.

In this embodiment, the case where the developing roller traveling 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 remaining life DP of the developing roller. That is, first, as shown in Table 4, the developing roller running distance correction coefficient k is divided into a plurality of correction coefficients (k1 to k3) according to the range of the remaining life DP of the developing roller. Then, the CPU 501 can use the above-mentioned developing roller traveling distance correction coefficient k as a correction coefficient divided according to the remaining life DP of the developing roller. The plurality of correction coefficients are stored in, for example, the DT memory m2 and read by the CPU 501 as appropriate.

Then, the correction coefficient classified according to the remaining life DP of the developing roller in Table 4 may be applied only to the normal mode or the high density mode, or may be applied to both modes. Further, although Table 4 describes the case where the developing roller traveling distance correction coefficient k is changed according to the remaining life DP of the developing roller 4, the present invention is not limited to this. It may be changed according to the toner remaining amount TP, or the remaining life DP of the developing roller 4 and the toner remaining amount TP may be used together. It suffices that the developing roller correction coefficient k be appropriately determined according to the change in the parameter that contributes to the deterioration of the developing roller 4 used.

[Example 2]
In this embodiment, the correction coefficient is also stored in the O memory m1 mounted in the drum cartridge 210, and the correction coefficient is determined together with the correction coefficient stored in the DT memory m2 mounted in the developing cartridge 200. It is a thing. As shown in FIG. 11, the current flowing between the developing roller and the photosensitive drum changes depending on the film thickness of the carrier transfer layer of the photosensitive drum. That is, the life of the developing roller may change depending on the state of the drum cartridge, which is determined from the degree of wear of the photosensitive drum. Therefore, as shown in Table 5, the correction coefficient (second correction coefficient) divided into a plurality according to the remaining life of the drum cartridge is also stored in the O memory m1 mounted on the drum cartridge 210. By determining the final developing roller running distance correction coefficient k together with the developing roller running distance correction coefficient described above, it is possible to notify the user of the life more accurately.

[Development roller life calculation sequence in this embodiment]
A sequence for calculating the developing roller remaining life DP in this embodiment will be described. The description of the same parts as those of the first or second embodiment will be omitted. The remaining life of the drum cartridge is obtained from the rotational speed 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 calculated using the degree of wear. Using the tables of Tables 4 and 5, the corrected developing roller traveling distance Hu is set to the predetermined developing roller traveling distance Wu, the developing roller traveling distance correction coefficient kn stored in the DT memory m2, and the O memory m1. It is obtained by multiplying the stored developing roller travel distance correction coefficient on. The same applies to the corrected developing roller travel distances Hu ₀ and Hu ₁ described with reference to 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.
As described above, the life history of the developing cartridge 200 can be determined more appropriately by considering the driving history of the developing roller.

[Example 3]
In the present embodiment, a case will be described in which the rotational peripheral speed ratio between the photosensitive drum 1 and the developing roller 4 is changed by the image forming unit during printing in the high density mode. Specifically, the following settings were made by setting the potential and the rotation peripheral speed ratio as shown in Table 6. That is, high density/wide color gamut is realized in the image forming portions of yellow (Y), magenta (M), and cyan (C), and black (K), which is mainly used for text printing, has high density/wide color gamut. The setting is not such a setting that suppresses deterioration of the developing roller 4. As a result, when it is not necessary to set the rotation peripheral speed ratio between the photosensitive drum 1 and the developing roller 4 to a high value depending on how the developing cartridge 200 of each image forming unit is used, the developing roller 4 is unnecessarily set. Since it is not deteriorated, the number of times the developing cartridge 200 is replaced can be reduced.

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

The difference in the total corrected 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 the user 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). In FIG. 12B, the horizontal axis represents the remaining life DP of the developing roller and the vertical axis represents the remaining toner amount TP in FIG. 12A. The remaining toner amount TP is calculated according to each toner amount. FIG. 12C shows the state after the correction using the developing roller traveling distance correction coefficient k from FIG. 12B. For yellow (Y), magenta (M), and cyan (C), correction was performed as described in Example 1. However, for black (K), the rotational peripheral speed ratio between the developing roller 4 and the photosensitive drum 1 is not changed from the normal mode even in the high density mode, and therefore no correction is made (developing roller travel distance correction coefficient k=1). I chose As a result, when the high density mode is selected, the developing roller running distance is not unnecessarily corrected in the image forming unit that does not change the rotation peripheral speed ratio between the photosensitive drum 1 and the developing roller 4, and the developing cartridge 200 is properly performed. I was able to report the life of the.

Reference numeral 100... Image forming device, 200... Developing cartridge (developing device), 1... Photosensitive drum, 4... Developing roller, 303... Developing roller running distance calculation unit, 300... Control unit

Claims (12)

A rotatable image carrier,
A developing device having a developer carrier for supplying a developer to the image carrier to develop the electrostatic latent image on the image carrier,
A first mode in which the developer bearing member rotates at a first peripheral speed ratio with respect to the image bearing member, and a first mode in which the developer bearing member has a larger peripheral speed ratio with respect to the image bearing member. An image forming apparatus having a second mode of rotating at a peripheral speed ratio of 2,
Storage means for storing a first correction coefficient according to a rotational peripheral speed ratio between the image carrier and the developer carrier, and a life threshold of the developing device;
The development based on first drive amount information when the developer carrier operates in the first mode and second drive amount information when the developer carrier operates in the second mode. Control means for cumulatively adding or subtracting the driving amount information of the developer carrier with respect to the life judgment value of the apparatus, and updating the life judgment value,
The control unit reads the first correction coefficient stored in the storage unit and uses the first correction coefficient for the first drive amount information and/or the second drive amount information so that the same drive of the developer carrying member is performed. With respect to the amount, the size of the drive amount information that is cumulatively added or reduced by the second drive amount information is made larger than the size of the drive amount information that is cumulatively added or reduced by the first drive amount information, and the life is increased. An image forming apparatus that updates a judgment value. A rotatable image carrier,
A developing device having a developer carrier for supplying a developer to the image carrier to develop the electrostatic latent image on the image carrier,
A first mode in which the developer bearing member rotates at a first peripheral speed ratio with respect to the image bearing member, and a first mode in which the developer bearing member has a larger peripheral speed ratio with respect to the image bearing member. An image forming apparatus having a second mode of rotating at a peripheral speed ratio of 2,
Storage means for storing a first correction coefficient according to a rotational 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 cumulatively adding 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. Control means for cumulatively adding a second total value of driving amount information obtained by cumulatively adding driving amount information,
The control means is
The first correction coefficient is read out and used for the first total value and/or the second total value, and the life is judged by a sum based on the first total value and the second total value or by subtraction from an initial value. Calculate the value,
Image formation characterized in that, in the same drive amount of the developer carrying member, the sum or the subtraction magnitude by the second sum value is larger than the sum or the subtraction magnitude by the first sum value. apparatus. The image according to claim 1 or 2, wherein the control means compares the life judgment value with the life threshold value and judges whether the life judgment value exceeds or falls below the life threshold value. Forming equipment. Further comprising a remaining amount acquisition unit for acquiring the amount of the 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 remaining 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 claim 1, wherein the control unit makes a determination regarding a life of the developing device based on the life determination value and the life threshold value. The image forming apparatus has a plurality of image forming units including the image carrier and the developer carrier corresponding to the image carrier,
An image forming unit that operates in the first mode and the second mode when operating in the first mode or the second mode, and the image carrier even in the first mode or the second mode. In the case where there is an image forming unit whose rotational peripheral speed ratio with the developer carrying member is not the first peripheral speed ratio or the second peripheral speed ratio,
4. The driving amount information of the developer carrying member is corrected only in the image forming unit that operates in the first mode or the second mode among the plurality of image forming units. The image forming apparatus according to item 1. The image forming apparatus according to claim 1, wherein the first correction coefficient includes a plurality of correction coefficients according to the remaining life of the developer carrier. The image forming apparatus according to claim 7, wherein the smaller the remaining life of the developer carrier is, the larger the first correction coefficient is assigned. The control means further corrects the drive amount information of the developer carrier corrected by the first correction coefficient by a second correction coefficient according to the degree of wear of the image carrier. 9. The image forming apparatus according to any one of items 8 to 8. The image forming apparatus according to claim 9, wherein the second correction coefficient increases as the remaining life of the image carrier provided in the cartridge detachable from the image forming apparatus decreases. The image forming apparatus according to claim 10, wherein the second correction coefficient is stored in a storage unit provided in the cartridge. The image forming apparatus according to any one of claims 1 to 11, further comprising an informing unit for informing about a life of the developing device.

Images