JP2021051118A - Image forming apparatus and control method - Google Patents

Abstract

To provide an image forming apparatus that can predict the life of a photoreceptor.SOLUTION: An image forming apparatus develops an electrostatic latent image on a surface of a photoreceptor with a toner conveyed by a developer carrier that carries a developer composed of the toner and a carrier. The image forming apparatus comprises: a storage circuit 113 that stores first correspondence indicating a change in thickness of the photoreceptor with respect to the number of prints according to the amount of movement of the carrier to the photoreceptor due to a manufacturing variation; and a life acquisition circuit 112 that estimates the amount of movement of the carrier from the developer carrier to the photoreceptor in an initial stage of use of the image forming apparatus, refers to the first correspondence based on the amount of movement of the carrier obtained through the estimation, and acquires the number of prints corresponding to a thickness in which the end of life is reached as the life of the photoreceptor.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a technique for forming an image by an electrophotographic method using a two-component developer.

In an image forming apparatus using an electrophotographic method, image formation is executed by an electrostatic copying process, and toner is consumed every time in the image forming process.

In the two-component development method using charged toner and magnetic carriers as the development method used for image formation, development bias and charge of the photoconductor are used so that the carriers do not move from the developer carrier to the photoconductor. The condition has been adjusted. However, depending on the situation in which the image forming apparatus is used, for example, when the power supply of the image forming apparatus is turned on or off, when a jam occurs, or when the potential adjustment such as development bias is not stable, A small amount of carriers may move to the photoconductor.

When the carrier moves from the developer carrier to the photoconductor, the photoconductor and the intermediate transfer belt deteriorate. In the photoconductor, by cleaning the carriers adhering to the peripheral surface thereof, scraping of the photosensitive layer on the peripheral surface is promoted, and finally charging failure occurs. Further, in the intermediate transfer belt, the carrier causes unevenness on the surface thereof, and toner or the like stays in the concave portion, resulting in a final cleaning failure. As a result, the quality of the image deteriorates.

According to Patent Document 1, paper dust, toner, etc. are deposited on the peripheral surface of the intermediate transfer belt, which deteriorates the transfer performance. In order to know when to replace the deteriorated intermediate transfer belt, the relationship between the secondary transfer voltage level and the damage coefficient in the intermediate transfer belt is determined. For example, when the secondary transfer voltage level is "1", "2", and "3", the damage coefficients in the case of monochrome image formation are "1", "1.2", and "1.5", respectively. It is stipulated. The damage index is calculated by integrating the damage coefficient and the operation time of each means under a predetermined image formation condition, and then the cumulative value of the damage index is calculated for the entire operation period. When this cumulative value reaches a certain value (for example, 35,000), the life of the intermediate transfer belt is defined. When the cumulative value exceeds a certain value, a display prompting the user to replace the intermediate transfer belt is displayed.

Japanese Unexamined Patent Publication No. 2000-305379

However, as in Patent Document 1, when it is determined that the intermediate transfer belt has reached the end of its life when the cumulative value of the damage index exceeds a certain value for all the image forming apparatus, the intermediate transfer belt is subjected to the manufacturing process. Since there are individual differences due to variations, in reality, it may be wasteful to replace the intermediate transfer belt that has not reached the end of its useful life. On the contrary, when it is judged that the intermediate transfer belt has reached the end of its life, the life of the intermediate transfer belt may have already expired due to individual differences, and as a result, the image quality is deteriorated. There is also.

Further, the same problem occurs not only in the intermediate transfer belt but also in the photoconductor.

The present disclosure provides an image forming apparatus and a control method capable of solving the above-mentioned problems and predicting the life of a photoconductor included in the image forming apparatus even when there are variations during manufacturing. The purpose is to do.

In order to achieve the above object, one aspect of the present disclosure is an image forming apparatus that develops an electrostatic latent image on the surface of a photoconductor with toner conveyed by a developer carrier that carries a developer containing a toner and a carrier. Therefore, the first correspondence relationship indicating the change in the film thickness of the photoconductor with respect to the operating amount of the image forming apparatus is stored according to the amount of movement of the carrier from the developer carrier to the photoconductor due to manufacturing variation. In the initial stage of use of the image forming apparatus, the storage means, the estimation means for estimating the movement amount of the carrier, and the first correspondence relationship based on the movement amount of the carrier obtained by the estimation are referred to, and the lifetime is reached. It is characterized by providing an acquisition means for acquiring the operating amount corresponding to the reached film thickness as the life of the photoconductor.

Here, further, an intermediate transfer body to which the toner image formed by developing the electrostatic latent image is transferred is provided, and a part of the carrier transferred to the photoconductor is placed on the peripheral surface of the intermediate transfer body. The storage means further establishes a second correspondence relationship indicating the transition of the number of carrier dents on the peripheral surface of the intermediate transfer material with respect to the operating amount according to the amount of carrier movement caused by the manufacturing variation. The acquisition means further refers to the second correspondence relationship based on the movement amount of the carrier obtained by estimation, and determines the operating amount corresponding to the number of dents reaching the life of the intermediate transfer material. It may be acquired as the life.

Here, the storage means further indicates a change in the amount of carrier transfer from the developer carrier to the photoconductor with respect to the amount of the developer conveyed in the developer carrier due to manufacturing variations. The relationship is memorized, and the estimation means refers to the sub-estimation means for estimating the amount of the developer transported by the developer carrier in the initial stage and the third correspondence relationship, and estimates the relationship. It may include a moving amount acquisition means for acquiring the moving amount of the carrier corresponding to the conveyed amount of the obtained developer.

Here, the storage means further establishes a fourth correspondence relationship indicating a change in a predetermined development bias applied to the developer carrier with respect to the amount of the developer conveyed in the developer carrier due to manufacturing variation. By switching the development bias applied to the developer carrier, the density of the toner image formed on the photoconductor is different, and the sub-estimating means has a predetermined pattern in the initial stage. With reference to the development bias acquisition means for developing the electrostatic latent image of the above and obtaining the development bias to obtain a predetermined toner concentration and the fourth correspondence relationship, the amount of the developer corresponding to the obtained development bias is determined. The transport amount acquisition means to be acquired may be included.

Here, the storage means further, in response to environmental information that fluctuates depending on the environment, a predetermined development applied to the developer carrier with respect to the amount of the developer transported by the developer carrier due to manufacturing variation. The fifth correspondence relationship indicating the change in the bias is stored, and the density of the toner image formed on the photoconductor differs by switching the development bias applied to the developer carrier, and the sub-estimation means. Acquired the environmental information acquisition means for acquiring environmental information, and the development bias acquisition means for developing an electrostatic latent image of a predetermined pattern to obtain a development bias having a predetermined toner concentration in the initial stage. It may include a transport amount acquisition means for acquiring the transport amount of the developer corresponding to the obtained development bias by referring to the fifth correspondence relationship according to the environmental information.

Here, it is also possible to provide a correction means for correcting the life of the acquired photoconductor according to the usage status of the photoconductor.

Here, the correction means may correct when a jam occurs in the recording sheet.

Here, it is also possible to provide a correction means for correcting the life of the acquired intermediate transfer body according to the usage status of the intermediate transfer body.

Here, the correction means may correct when a jam occurs in the recording sheet.

Further, one aspect of the present disclosure is a control method used in an image forming apparatus that develops an electrostatic latent image on the surface of a photoconductor with toner conveyed from a developer carrier that carries a developer composed of toner and a carrier. Therefore, the image forming apparatus stores the first correspondence relationship indicating the change in the film thickness of the photoconductor with respect to the operating amount of the image forming apparatus according to the amount of movement of the carrier to the photoconductor due to the manufacturing variation. The control method includes an estimation step of estimating the amount of carrier movement from the developer carrier to the photoconductor in the initial stage of use of the image forming apparatus, and an estimation step of the carrier movement amount obtained by the estimation. Based on the above, the first correspondence relationship is referred to, and the working amount corresponding to the film thickness reaching the life is included as the life of the photoconductor, including the acquisition step.

According to the above configuration, even if there are variations during manufacturing, the life of the photoconductor provided in the image forming apparatus can be predicted, which is an excellent effect.

It is a figure which shows the schematic structure of the image forming apparatus 10. The figure which shows the structure of the image formation unit 14 is shown. It is a block diagram which shows the structure of the control circuit 100. The cross-sectional view of the developer carrier 27K is shown. It is a graph which shows the change of the transport amount of the developer from the developer carrier 27K. The cross-sectional view at the position where the developer carrier 27K and the photoconductor drum 23K are close to each other is shown. It is a graph which shows the change of the movement amount of a carrier from a developer carrier 27K. It is a figure which shows a mode that a dent (carrier dent) is generated on the peripheral surface of an intermediate transfer belt 21 by a carrier. It is a graph which shows the change of the carrier dents. It is a graph which shows the change of the film thickness of the photoconductor drum 23K. It is a graph which shows the correspondence relationship between the development bias corresponding to the case where a predetermined toner density is obtained, and the transfer amount / Ds. It is a graph which shows the change of the carrier dents when a trouble occurs. It is a flowchart which shows the operation about the estimation and replacement of the life of the intermediate transfer belt 21 and the photoconductor drum 23K. It is a flowchart which shows the operation of the estimation of the life of an intermediate transfer belt and a photoconductor drum.

1 Embodiment The image forming apparatus 10 as one embodiment according to the present disclosure will be described with reference to the drawings.

1.1 Image forming apparatus 10
As shown in FIG. 1, the image forming apparatus 10 is a tandem type color multifunction device (MFP: MultiFunction Peripheral) having the functions of a scanner, a printer, and a copier.

As shown in this figure, the image forming apparatus 10 is provided with a paper feeding unit 13 for accommodating and feeding a recording sheet at the bottom of the housing. A printer 12 that forms an image by an electrophotographic method is provided above the paper feed unit 13. Above the printer 12, an image reader 11 that reads a document and generates image data, and an operation panel 19 that displays an operation screen and accepts an input operation from a user are provided. Further, inside the housing, a humidity sensor 41 for measuring the humidity inside is provided.

The image reader 11 has an automatic document transfer device. The automatic document transfer device transfers the documents set in the document tray to the document glass plate one by one via the transfer path. The image reader 11 reads the document transported to a predetermined position on the document glass plate by the automatic document transport device or the image placed on the document glass plate by the user by moving the scanner, and red (R). Image data consisting of multi-valued digital signals of green (G) and blue (B) is obtained.

The image data of each color component obtained by the image reader 11 undergoes various data processing in the control circuit 100, and further, the reproduced colors of yellow (Y), magenta (M), cyan (C), and black (K) are reproduced. Converted to image data.

The printer 12 includes an intermediate transfer belt 21 (intermediate transfer body) stretched by a drive roller, a driven roller, and a backup roller, and a density sensor 42 for measuring the density of a toner image formed on the peripheral surface of the intermediate transfer belt 21. Image-creating units 20Y, 20M, 20C, 20K, fixing units 50, control circuit 100, etc., which are arranged at predetermined intervals along the traveling direction X of the intermediate transfer belt 21 facing the secondary transfer roller 22 and the intermediate transfer belt 21. Consists of.

The image-creating units 20Y, 20M, 20C, and 20K image toner images of Y, M, C, and K colors, respectively. Specifically, as shown in FIG. 2, the image forming unit 20K includes a photoconductor drum 23K (photoreceptor) which is an image carrier, an LED array 25K for exposure scanning the surface of the photoconductor drum 23K, and a charging charger 24K. , A developer 26K, a cleaner, a primary transfer roller 28K, and the like. The developer 26K includes a developer carrier 27K, a regulating member 32K, and the like. The image forming units 20Y, 20M, and 20C also have the same configuration as the image forming unit 20K.

As shown in FIG. 2, in the image forming unit 20K, the photoconductor drum 23K is uniformly charged by the charging charger 24K and exposed by the LED array 25K, and an electrostatic latent image is formed on the surface of the photoconductor drum 23K. To. The electrostatic latent image is developed by a developing device of the corresponding color, a K-color toner image is formed on the surface of the photoconductor drum 23K, and the toner image is a primary transfer arranged on the back surface side of the intermediate transfer belt 21. It is transferred onto the surface of the intermediate transfer belt 21 by the electrostatic action of the roller 28K.

The image-creating units 20Y, 20M, and 20C are the same as those of the image-creating unit 20K, and the Y to C color toner images are transferred onto the surface of the intermediate transfer belt 21.

The image formation timing of each color is shifted so that the toner images of colors Y to K are multiple-transferred on the intermediate transfer belt 21.

Returning to FIG. 1, the paper feed unit 13 includes paper cassettes 60, 61, 62 for accommodating recording sheets of different sizes, and pickup rollers 63, 64 for feeding the recording sheets from the paper cassettes to the transport path. , 65.

A recording sheet is fed from any of the paper feed cassettes 13 in accordance with the image drawing operation by the image drawing units 20Y to 20K.

The recording sheet is conveyed on the transport path to the secondary transfer position where the secondary transfer roller 22 and the backup roller face each other across the intermediate transfer belt 21, and at the secondary transfer position, the secondary transfer roller 22 is electrostatically charged. By the action, the Y to K color toner images multiple-transferred on the intermediate transfer belt 21 are secondarily transferred to the recording sheet. The recording sheet on which the Y to K color toner images are secondarily transferred is further conveyed to the fixing portion 50.

When the toner image on the surface of the recording sheet passes through the fixing nip formed between the heating roller 51 of the fixing portion 50 and the pressure roller 52 pressed against the heating roller 51, the toner image of the recording sheet is heated and pressed. The recording sheet is fused and fixed to the surface, and after passing through the fixing portion 50, the recording sheet is sent to the discharge tray 15.

The operation panel 19 is provided with a display unit composed of a liquid crystal display board or the like, and displays contents set by the user and various messages. The operation panel 19 receives an instruction to start copying, a setting of the number of copies, a setting of copying conditions, a setting of a data output destination, and the like from the user, and notifies the control circuit 100 of the received contents.

When it is determined that the intermediate transfer belt 21 or the photoconductor drum 23K has reached the end of its useful life, the operation panel 19 is moved from the printer main control circuit 111 via the main control unit 101a and the input / output circuit 108, as will be described later. Then, the replacement request of the intermediate transfer belt 21 or the photoconductor drum 23K is received. Upon receiving the replacement request, the operation panel 19 displays the replacement request for the intermediate transfer belt 21 or the photoconductor drum 23K.

1.2 The gap between the developer carrier 27K and the restricting member 32K After that, the image forming portion 20K will be described as a representative of the image forming portions 20Y to 20K. Since the image-forming units 20Y, 20M, and 20C have the same configuration as the image-creating unit 20K, the description of the image-creating units 20Y, 20M, and 20C will be omitted.

As shown in FIG. 4, the peripheral surface 27Ka of the developer carrier 27K and the tip portion 32Ka of the regulating member 32K have a gap of 29K, and the tip portion 32Ka of the regulating member 32K is the peripheral surface 27Ka of the developer carrier 27K. A regulating member 32K is provided so as to face the side. Here, the length of the gap 29K is represented by the width Db.

The regulating member 32K regulates the amount of the developer (supported amount in the region) conveyed to the region (development position) facing the photoconductor drum 23K on the developer carrier 27K. When the width Db is wide, the amount of the developer transported increases. On the other hand, when the width Db is narrow, the amount of the developer transported is small.

The width Db varies from product to product (image forming apparatus 10) at the time of manufacture, although it is within the tolerance. Therefore, the amount of the developer transported by the developer carrier 27K also varies from product to product during production.

FIG. 5 is a graph showing a change in the amount of the developer conveyed by the developer carrier 27K with respect to the width Db that fluctuates due to variations during manufacturing. In this graph, the horizontal axis shows the width Db, and the vertical axis shows the amount of the developer transported by the developer carrier 27K. Further, this graph shows the range 201 of the variation of the width Db at the time of manufacturing. The range 201 is a range from the lower limit 203 to the upper limit 204.

As shown in the curve 202 showing the change in the transport amount in this graph, the transport amount of the developer monotonously increases as the width Db becomes wider.

The transport amounts corresponding to the lower limit 203 and the upper limit 204 are the transport amount B and the transport amount A, respectively.

1.3 Gap between the developer carrier 27K and the photoconductor drum 23K As shown in FIG. 6, the position where the peripheral surface of the developer carrier 27K and the peripheral surface of the photoconductor drum 23K are closest to each other (development position 30K). ), The distance between the peripheral surface of the developer carrier 27K and the peripheral surface of the photoconductor drum 23K is represented by the width Ds.

When a two-component developer is used, as shown in this figure, a developer containing toner and a carrier is attached to the peripheral surface of the developer carrier 27K.

At the developing position 30K, a voltage (development bias) is applied to the developing agent carrier 27K, and the toner contained in the developing agent is moved to the latent image portion of the photoconductor drum 23K by an electric field. On the other hand, the carriers contained in the developer are left on the peripheral surface of the developer carrier 27K by the principal magnetic force of the developer carrier 27K. Normally, by adjusting the development bias and the surface potential of the photoconductor drum 23K, only the toner moves to the peripheral surface of the photoconductor drum 23K, and the carrier does not move to the photoconductor drum 23K side.

1.4 Adhesion of Carriers to Photoreceptor Drum 23K As described above, carriers contained in the developer usually do not move from the developer carrier 27K to the photoconductor drum 23K side.

However, depending on the situation in which the image forming apparatus 10 operates, a minute amount of carriers may move to the photoconductor drum 23K. The amount of movement is related to the amount of transport / Ds and the strength of the magnetic force that keeps the carrier on the developer carrier 27K.

FIG. 7 is a graph showing the change in the amount of carrier movement from the developer carrier 27K.

As shown in FIG. 7, when the width Ds is narrow and the magnetic force of the developer carrier 27K is weak in a state where the amount of the developer conveyed is large, the carrier easily moves to the photoconductor drum 23K side.

In this figure, the horizontal axis represents the amount of transport / width Ds, and the vertical axis represents the amount of carrier movement to the photoconductor drum 23K. Further, the curve 211 of the change in the amount of movement of the carrier when the magnetic force is large is shown, and the curve 212 of the change in the amount of movement of the carrier when the magnetic force is small is shown.

In both the case where the magnetic force is large and the case where the magnetic force is small, the amount of movement of the carrier increases monotonically as the amount of transport / Ds increases. Further, in the entire range of the conveyed amount / Ds, the moving amount of the carrier when the magnetic force is small is larger than the moving amount of the carrier when the magnetic force is large.

The transport amounts / Ds (B216) and (A217) shown in FIG. 7 correspond to the transport amounts B206 and A205 shown in FIG. 5, respectively.

The carrier movement amount B1 is the carrier movement amount in the case of the transport amount / Ds (B216). Further, the carrier movement amounts A1 and A2 are the carrier movement amounts when the magnetic force is large (211) and when the magnetic force is small (212), respectively, in the case of the transport amount / Ds (A217).

As described above, FIG. 7 shows a third correspondence relationship showing a change in the amount of carrier transfer from the developer carrier 27K to the photoconductor drum 23K with respect to the amount of the developer conveyed in the developer carrier 27K due to manufacturing variation. Represents.

1.5 Life of the intermediate transfer belt 21 FIG. 8 is a diagram showing how a carrier causes a dent (carrier dent) on the peripheral surface of the intermediate transfer belt 21.

As shown in FIG. 8, the carrier 230 moved from the developer carrier 27K to the photoconductor drum 23K side is sandwiched between the peripheral surface of the intermediate transfer belt 21 at the primary transfer position 232, and is sandwiched by the sandwiched carrier 230. ,, Recesses 231 and 232, ... Are formed on the peripheral surface of the intermediate transfer belt 21. If the peripheral surface of the intermediate transfer belt 21 has more dents, the toner stays inside the dents without being cleaned, and the peripheral surface of the intermediate transfer belt 21 becomes poorly cleaned, and the life of the intermediate transfer belt 21 ends. The life of the intermediate transfer belt 21 can be estimated by predicting the number of dents on the peripheral surface of the intermediate transfer belt 21.

FIG. 9 is a graph showing the correspondence between the number of printed sheets (operating amount) and the number of carrier dents.

In the present disclosure, it is determined which curve shown in FIG. 9 corresponds to, and the number of printed sheets to be used for the life is estimated.

In FIG. 9, the horizontal axis shows the number of printed sheets, and the vertical axis shows the number of dents on the carrier. Curves A2, A1 and B1 correspond to the carrier movement amounts A2, A1 and B1 shown in FIG. 7, respectively, and show changes in the number of dents on the carriers as the number of printed sheets increases. In each of the curves A2, A1 and B1, the number of dents on the carrier increases monotonically as the number of printed sheets increases.

The figure also shows the poor cleaning line 251. When the number of dents on the carrier exceeds the cleaning failure line 251, the intermediate transfer belt 21 is determined to be poorly cleaned. That is, it is determined that the life of the intermediate transfer belt 21 has expired.

The points where the curves A2, A1 and B1 intersect with the cleaning failure line 251 are different. That is, the life of the intermediate transfer belt 21 varies according to the curves A2, A1 and B1. The range of variation in life is between the number of printed sheets 252 and the number of printed sheets 253.

When estimating the number of prints to be the life, for example, when the state of the intermediate transfer belt 21 corresponds to the curve indicated by B1, the number of prints (253) at the intersection of the curve B1 and the cleaning defective line 251 is defined as the life. To do.

As described above, FIG. 9 shows the second correspondence relationship showing the transition of the number of dents on the peripheral surface of the intermediate transfer belt 21 with respect to the operating amount according to the amount of movement of the carrier due to the manufacturing variation.

When a new developer carrier is attached and the intermediate transfer belt is used, in the graph shown in FIG. 9, a curve showing the transition of the number of carrier dents after that time is shown on the vertical axis of the graph. The life may be corrected by translating in the direction.

1.6 Life of the photoconductor drum 23K When the carrier is moved to the photoconductor drum 23K, the carrier adhering to the peripheral surface of the photoconductor drum 23K is scraped off by the blade 31K (FIG. 2). The blade 31K wears the peripheral surface (photoreceptor film) of the photoconductor drum 23K when scraping the carrier. If the film thickness of the photoconductor drum 23K is reduced by a predetermined threshold value or more, the charged charge cannot be maintained and the life of the photoconductor drum 23K is exhausted. The life of the photoconductor drum 23K can be estimated by predicting the wear of the photoconductor film on the peripheral surface of the photoconductor drum 23K.

FIG. 10 is a graph showing a change in the film thickness of the photoconductor drum 23K.

In the present disclosure, it is determined which curve shown in FIG. 10 corresponds to, and the number of printed sheets (operating amount) that reaches the end of its life is estimated.

In FIG. 10, the horizontal axis shows the number of printed sheets, and the vertical axis shows the film thickness of the photoconductor drum 23K. Curves A2, A1 and B1 correspond to the carrier movement amounts A2, A1 and B1 shown in FIG. 7, respectively, and show changes in the film thickness of the photoconductor drum 23K as the number of printed sheets increases. In each of the curves A2, A1 and B1, the film thickness of the photoconductor drum 23K decreases monotonically as the number of printed sheets increases.

The figure also shows the poorly charged line 261. When the film thickness is lower than the poorly charged line 261, the photoconductor drum 23K is determined to be poorly charged. That is, it is determined that the life of the photoconductor drum 23K has expired.

The points at which the curves A2, A1 and B1 intersect with the poorly charged line 261 are different. That is, the life of the photoconductor drum 23K varies according to the curves A2, A1 and B1. The range of variation in life is between the number of printed sheets 262 and the number of printed sheets 263.

When estimating the number of prints to be the life, for example, when the state of the photoconductor drum 23K corresponds to the curve indicated by B1, the point where the curve B1 and the poorly charged line 261 intersect is defined as the life of the number of prints.

As described above, FIG. 10 shows a change in the film thickness of the photoconductor with respect to the operating amount of the image forming apparatus 10 according to the amount of movement of the carrier from the developer carrier 27K to the photoconductor drum 23K due to manufacturing variation. It represents the first correspondence.

1.7 Life Estimation The procedure shown below is performed immediately before the image forming apparatus 10 is shipped from the manufacturing plant or immediately after the image forming apparatus 10 is shipped from the manufacturing plant. Immediately before shipping from a manufacturing plant or immediately after shipping from that manufacturing plant is called the initial stage.

The development bias to be applied is changed with respect to the predetermined test pattern (latent image pattern) so as to take a plurality of values, and the test pattern is developed on the peripheral surface of the photoconductor drum 23K, and each development is performed. The toner image of the test pattern obtained for each bias is transferred onto the peripheral surface of the intermediate transfer belt 21. Next, the toner density of the toner image of the test pattern transferred onto the peripheral surface of the intermediate transfer belt 21 and developed with different development biases is measured using the density sensor 42 (FIG. 1). Next, the development bias at which a predetermined toner concentration is obtained is recorded.

If the distance Ds between the peripheral surface of the developer carrier 27K and the peripheral surface of the photoconductor drum 23K is closer, a predetermined toner concentration can be obtained with a lower development bias.

Further, the development bias when a predetermined toner concentration is obtained is also affected by the environment (temperature).

FIG. 11 is a graph showing the correspondence relationship between the development bias corresponding to the case where a predetermined toner concentration is obtained and the conveyed amount / Ds. In this graph, the horizontal axis shows the amount of transport / Ds, and the vertical axis shows the development bias corresponding to the case where a predetermined toner concentration is obtained.

Further, this graph shows a curve 272 showing a change in development bias in a low humidity environment and a curve 271 showing a change in development bias in a high humidity environment.

In both the cases of the curve 272 and the curve 271, the development bias corresponding to the case where the predetermined toner concentration is obtained increases monotonically according to the increase in the conveyed amount / Ds.

When the development bias (C) corresponding to the case where a predetermined toner concentration is obtained is obtained by the measurement by the density sensor 42, the transfer amount / Ds (D) corresponding to the development bias (C) is used with reference to FIG. ). Specifically, in FIG. 11, an intersection 274 that passes through the obtained development bias point (C) and intersects the straight line 273 parallel to the horizontal axis and the curve 272 is obtained, and from the intersection 274, the vertical axis is obtained. Find the intersection (D) where the straight line 275 parallel to and the horizontal axis intersects. The finally obtained intersection (D) is the transport amount / Ds (D) corresponding to the development bias.

Here, it is assumed that the image forming apparatus 10 is installed in an environment of low humidity according to the humidity measured by the humidity sensor 41.

As described above, FIG. 11 shows the fourth correspondence relationship showing the change in the predetermined development bias applied to the developer carrier 27K with respect to the amount of the developer conveyed in the developer carrier 27K due to the manufacturing variation. There is. Further, FIG. 11 shows changes in a predetermined development bias applied to the developer carrier 27K with respect to the amount of the developer transported by the developer carrier 27K due to manufacturing variations according to environmental information that fluctuates depending on the environment. It represents the fifth correspondence shown.

Next, using FIG. 7, the carrier movement amount (E) corresponding to the transport amount / Ds (D) obtained above is obtained. Specifically, in FIG. 7, an intersection 214 that passes through the obtained transport amount / Ds (D) and intersects the straight line 213 parallel to the vertical axis and the curve 212 is obtained, and from the intersection 214, the horizontal axis Find the intersection (E) where the straight line 215 parallel to and the horizontal axis intersects. The finally obtained intersection (E) is the carrier movement amount (E) corresponding to the transport amount / Ds (D).

Next, using FIG. 9, the life (F) of the intermediate transfer belt 21 corresponding to the obtained carrier movement amount (E) is determined. Specifically, in FIG. 9, the curve E corresponding to the carrier movement amount (E) is selected, and the intersection 254 where the selected curve E and the cleaning defective line 251 intersect is obtained. Next, the number of prints (F) at the intersection 254 is read. The number of printed sheets (F) thus obtained is the life (F) of the intermediate transfer belt 21 corresponding to the carrier movement amount (E).

Next, using FIG. 10, the life (G) of the photoconductor drum 23K corresponding to the obtained carrier movement amount (E) is determined. Specifically, in FIG. 10, a curve E corresponding to the carrier movement amount (E) is selected, and an intersection 264 at which the selected curve E and the poorly charged line 261 intersect is obtained. Next, the number of prints (G) at the intersection 264 is read. The number of printed sheets (G) thus obtained is the life (G) of the photoconductor drum 23K corresponding to the carrier movement amount (E).

1.8 Carrier movement during use of the image forming apparatus 10 For example, when a trouble such as jamming of a recording sheet occurs and the printer 12 is stopped urgently, the development bias and the potential of the surface of the photoconductor drum 23K The balance is lost. In such a case, if the difference between the two potentials becomes large, a minute amount of carriers will move to the photoconductor drum 23K. When the carrier moves to the photoconductor drum 23K in such a usage situation, the life of the photoconductor drum 23K and the life of the intermediate transfer belt 21 are corrected.

Specifically, it is as follows.

FIG. 12 is a graph showing the correspondence relationship between the number of printed sheets and the number of carrier dents, as in FIG. 9. In this figure, curve 281 shows the change in the number of carrier dents estimated in the initial stage, and the number of prints 287 is the number of prints in the life of the intermediate transfer belt 21 estimated in this initial stage.

When a jam occurs in the image forming apparatus 10, the curve 281 after the time point 282 is translated in the vertical direction of this graph at the time point 282 when the jam occurs. As a result, the curve 281 becomes a curve 283. Further, when a jam occurs, at the time point 284 when the jam occurs, the curve 283 after the time point 284 is translated in the vertical direction of this graph. As a result, the curve 283 becomes the curve 285.

The number of printed sheets at the point where the curve 285 thus obtained intersects the cleaning defective line 288 is the number of sheets with the corrected life.

In the above, the correction of the life of the intermediate transfer belt 21 has been described, but in the case of the photoconductor drum 23 as well, the curve showing the transition of the film thickness of the photoconductor drum 23 is translated in parallel to move the photoconductor. The life of the drum 23 may be corrected.

The above-mentioned life correction may be performed when a condition that the carrier easily moves occurs, other than when a jam occurs. For example, the above-mentioned life may be corrected at a timing when the potential adjustment such as development bias is not stable, such as when the power supply of the image forming apparatus is turned on or off.

1.9 Control circuit 100
As shown in FIG. 3, the control circuit 100 includes a CPU 101, a ROM 102, a RAM 103, an image memory 104, an image processing circuit 105, a network communication circuit 106, a scanner control circuit 107, an input / output circuit 108, a printer control circuit 109, and the like. ing.

The CPU 101, ROM 102, and RAM 103 constitute the main control unit 101a.

The RAM 103 temporarily stores various control variables, the number of copies set by the operation panel 19, and provides a work area when the program is executed by the CPU 101.

The ROM 102 stores a control program for executing various jobs such as a copy operation.

The CPU 101 operates according to the control program stored in the ROM 102.

When the CPU 101 operates according to the control program, the main control unit 101a unifies the image memory 104, the image processing circuit 105, the network communication circuit 106, the scanner control circuit 107, the input / output circuit 108, the printer control circuit 109, and the like. Control.

Further, the main control unit 101a receives the user's operation from the operation panel 19. When the user's operation is a print instruction, the main control unit 101a causes the printer control circuit 109 to execute the image forming process. When the user's operation is another instruction, the main control unit 101a causes the other processing to be executed. For example, the main control unit 101a receives set completion information from the operation panel 19 indicating that a new developer carrier has been set by the manufacturer. Upon receiving the set completion information, the main control unit 101a outputs the set completion information to the life acquisition circuit 112 via the printer main control circuit 111, which will be described later.

The image memory 104 temporarily stores image data such as a print job.

The image processing circuit 105, for example, performs various data processing on the image data of each color component of R, G, and B obtained by the image reader 11, and performs various data processing on the reproduced colors of Y, M, C, and K. Convert to image data.

The network communication circuit 106 accepts a print job from an external terminal device such as a PC (personal computer) via a network such as a LAN.

The scanner control circuit 107 controls the image reader 11 to execute an operation of reading an image of a document.

The printer control circuit 109 will be described below.

1.10 Printer control circuit 109
As shown in FIG. 3, the printer control circuit 109 includes a printer main control circuit 111, a life acquisition circuit 112, a storage circuit 113, and the like.

(1) Printer main control circuit 111
The printer main control circuit 111 uniformly controls the feeding operation from the paper feeding unit 13 and the image forming operation of the image forming units 20Y to 20K of the printer 12 to execute the image forming operation.

Further, the printer main control circuit 111 controls the life acquisition circuit 112 to perform a process for acquiring the life.

The printer main control circuit 111 determines whether or not there is a usage situation in which the carrier moves from the developer carrier 27K to the photoconductor drum 23K. For example, it is determined whether or not an event that causes the operation of the printer 12 to be stopped urgently occurs due to jamming of the recording sheet or the like. When it is determined that there is a usage situation in which the carrier moves, the printer main control circuit 111 outputs an emergency stop signal to the life acquisition circuit 112 to correct the life of the intermediate transfer belt 21 and the photoconductor drum 23K. Let me.

Further, the printer main control circuit 111 determines whether or not the intermediate transfer belt 21 or the photoconductor drum 23K has reached the end of its useful life. When it is determined that the intermediate transfer belt 21 or the photoconductor drum 23K has reached the end of its useful life, the printer main control circuit 111 sends the intermediate transfer belt to the operation panel 19 via the main control unit 101a and the input / output circuit 108. 21 or the photoconductor drum 23K replacement request is output.

(2) Memory circuit 113
The storage circuit 113 (storage means) is composed of, for example, a non-volatile semiconductor memory or the like. Of course, the storage circuit 113 may be composed of a hard disk.

The storage circuit 113 includes an area for storing the life of the intermediate transfer belt 21 and the life of the photoconductor drum 23K.

Further, the storage circuit 113 has a data table in which curves and straight lines showing changes in the graphs shown in FIGS. 7, 9, 10 and 11 are stored in advance as data. The storage circuit 113 may store in advance the curves and straight lines showing the changes in the graphs shown in FIGS. 7, 9, 10 and 11 as functions.

That is, the storage circuit 113 stores the above-mentioned first correspondence, second correspondence, third correspondence, fourth correspondence, and fifth correspondence in advance.

(3) Life acquisition circuit 112
The life acquisition circuit 112 receives the set completion information from the main control unit 101a via the printer main control circuit 111. Further, when it is determined by the printer main control circuit 111 that the carrier has moved from the developer carrier 27K to the photoconductor drum 23K, the life acquisition circuit 112 is urgent from the printer main control circuit 111. Receive a stop signal.

(A) Upon receiving the set completion information, the life acquisition circuit 112 (development bias acquisition means, sub-estimation means) causes the printer main control circuit 111 to form a toner image of a predetermined test pattern, and the toner concentration thereof. By executing the measurement, the development bias (C) when a predetermined toner concentration is obtained is acquired.

Further, the life acquisition circuit 112 (environmental information acquisition means, sub-estimation means) acquires humidity (environmental information) from the humidity sensor 41.

Further, the life acquisition circuit 112 estimates the life of the intermediate transfer belt 21 and the photoconductor drum 23K according to the procedures (a-1) to (a-4) shown below. In the following procedures (a-1) to (a-4), calculations are performed using the data tables corresponding to each graph. The method is not limited to this. A function stored in the storage circuit 113 and corresponding to each graph may be used to perform an operation.

(A-1) The life acquisition circuit 112 (conveyance amount acquisition means, sub-estimation means) obtains the transfer amount / Ds (D) corresponding to the acquired development bias (C) using FIG. 11.

FIG. 11 is a graph showing the correspondence relationship between the development bias corresponding to the case where a predetermined toner concentration is obtained and the conveyed amount / Ds.

The life acquisition circuit 112 reads out the data table corresponding to the graph shown in FIG. 11 from the storage circuit 113.

Next, using the read data table, the life acquisition circuit 112 passes through the obtained development bias point (C) in the graph shown in FIG. 11, and has a straight line 273 parallel to the horizontal axis and a curve 272. The calculation is performed to obtain the intersection 274 at which the two intersect, and from the intersection 274, the calculation is performed to obtain the intersection (D) at which the straight line 275 parallel to the vertical axis and the horizontal axis intersect. The finally obtained intersection (D) is the transport amount / Ds (D) corresponding to the development bias.

(A-2) Next, the life acquisition circuit 112 (estimating means) obtains a carrier movement amount (E) corresponding to the obtained transport amount / Ds (D) using FIG. 7.

FIG. 7 is a graph showing the correspondence between the amount of transport / Ds and the amount of carrier movement from the developer carrier 27K.

The life acquisition circuit 112 reads out the data table corresponding to the graph shown in FIG. 7 from the storage circuit 113.

Next, using the read data table, the life acquisition circuit 112 passes through the obtained transport amount / Ds (D) in the graph shown in FIG. 7, and has a straight line 213 parallel to the vertical axis and a curve 212. The calculation is performed to obtain the intersection 214 where the two intersect, and from the intersection 214, the calculation is performed to obtain the intersection (E) where the straight line 215 parallel to the horizontal axis and the horizontal axis intersect. The finally obtained intersection (E) is the carrier movement amount (E) corresponding to the transport amount / Ds (D).

(A-3) Next, the life acquisition circuit 112 (acquisition means) determines the life (F) of the intermediate transfer belt 21 corresponding to the carrier movement amount (E) using FIG.

FIG. 9 is a graph showing the correspondence between the number of printed sheets and the number of carrier dents.

The life acquisition circuit 112 reads out the data table corresponding to the graph shown in FIG. 9 from the storage circuit 113.

Next, the life acquisition circuit 112 performs an operation of selecting the curve E corresponding to the obtained carrier movement amount (E) in the graph shown in FIG. 9 using the read data table, and the selected curve E is performed. And the calculation to find the intersection 254 where the cleaning failure line 251 intersects. Next, the life acquisition circuit 112 reads the number of prints (F) at the intersection 254. The number of printed sheets (F) thus obtained is the life (F) of the intermediate transfer belt 21 corresponding to the carrier movement amount (E).

(A-4) Next, the life acquisition circuit 112 (acquisition means) determines the life (G) of the photoconductor drum 23K corresponding to the carrier movement amount (E) using FIG.

FIG. 10 is a graph showing the correspondence between the number of printed sheets and the film thickness of the photoconductor drum 23K.

The life acquisition circuit 112 reads out the data table corresponding to the graph shown in FIG. 10 from the storage circuit 113.

Next, the life acquisition circuit 112 uses the read data table to perform an operation of selecting the curve E corresponding to the obtained carrier movement amount (E) in the graph shown in FIG. , The calculation for finding the intersection 264 where the poorly charged line 261 intersects is performed. Next, the life acquisition circuit 112 reads the number of prints (G) at the intersection 264. The number of printed sheets (G) thus obtained is the life (G) of the photoconductor drum 23K corresponding to the carrier movement amount (E).

(B) Upon receiving the emergency stop signal, the life acquisition circuit 112 (correction means) corrects the life of the intermediate transfer belt 21 and the photoconductor drum 23K.

Specifically, for the intermediate transfer belt 21, the life acquisition circuit 112 has a curve showing the change in the number of carrier dents shown in FIG. 12, in the vertical direction of the graph after the time when the emergency stop signal is received. Performs a translation operation. The same calculation is performed for the photoconductor drum 23K.

As described above, the life acquisition circuit 112 may correct the acquired life of the photoconductor drum 23K according to the usage status of the photoconductor drum 23K. Here, the life acquisition circuit 112 may correct when a jam occurs in the recording sheet.

Further, the life acquisition circuit 112 may correct the acquired life of the intermediate transfer belt 21 according to the usage status of the intermediate transfer belt 21. Here, the life acquisition circuit 112 may correct when a jam occurs in the recording sheet.

1.11 Operation in the image forming apparatus 10 An operation relating to the life of the intermediate transfer belt 21 and the photoconductor drum 23K in the image forming apparatus 10 will be described.

(1) The operation related to the estimation and replacement of the life of the intermediate transfer belt 21 and the photoconductor drum 23K will be described with reference to the flowchart shown in FIG.

The main control unit 101a receives the set completion information indicating that the new developer carrier has been set by the manufacturer from the operation panel 19 (step S101).

The life acquisition circuit 112 causes the printer main control circuit 111 to read the initial density, and acquires the humidity from the humidity sensor as environmental information (step S102).

Next, the life acquisition circuit 112 estimates the life of the intermediate transfer belt 21 and the photoconductor drum 23K (step S103).

The printer main control circuit 111 determines whether or not there is a usage situation in which the carrier moves from the developer carrier 27K to the photoconductor drum 23K (step S104).

When it is determined that there is a usage situation in which the carrier moves (“YES” in step S104), the life acquisition circuit 112 corrects the life of the intermediate transfer belt 21 and the photoconductor drum 23K (step S105).

The printer main control circuit 111 determines whether or not the intermediate transfer belt 21 or the photoconductor drum 23K has reached the end of its useful life (step S106).

When it is determined that the intermediate transfer belt 21 or the photoconductor drum 23K has not reached the number of lifespans (“NO” in step S106), the printer main control circuit 111 shifts control to S104 and continues the process.

When it is determined that the intermediate transfer belt 21 or the photoconductor drum 23K has reached the end of its useful life (“YES” in step S106), the printer main control circuit 111 passes through the main control unit 101a and the input / output circuit 108. A replacement request for the intermediate transfer belt 21 or the photoconductor drum 23K is output to the operation panel 19, and the operation panel 19 displays a replacement request for the intermediate transfer belt 21 or the photoconductor drum 23K (S107).

This completes the description of operations related to estimation and replacement of the life of the intermediate transfer belt 21 and the photoconductor drum 23K.

(2) Operation of Estimating the Life of the Intermediate Transfer Belt and the Photoreceptor Drum The operation of estimating the life of the intermediate transfer belt and the photoconductor drum will be described with reference to the flowchart shown in FIG.

The life acquisition circuit 112 obtains the transfer amount / Ds (D) corresponding to the development bias (C) using FIG. 11 (step S131).

Next, the life acquisition circuit 112 obtains the carrier movement amount (E) corresponding to the transport amount / Ds (D) using FIG. 7 (step S132).

Next, the life acquisition circuit 112 obtains the life (F) of the intermediate transfer belt 21 corresponding to the carrier movement amount (E) using FIG. 9 (step S133).

Next, the life acquisition circuit 112 obtains the life (G) of the photoconductor drum 23K corresponding to the carrier movement amount (E) using FIG. 10 (step S134).

From the above, the life of the intermediate transfer belt 21 and the life of the photoconductor drum 23K can be estimated.

1.12 Summary As described above, the image forming apparatus that develops the electrostatic latent image on the surface of the photoconductor drum with the toner conveyed by the developer carrier that carries the developer containing the toner and the carrier is caused by manufacturing variations. The first correspondence relationship indicating the change in the film thickness of the photoconductor with respect to the operating amount of the image forming apparatus is stored according to the amount of movement of the carrier from the developer carrier to the photoconductor drum, and the image forming apparatus is used. In the initial stage of the above, the amount of carrier movement is estimated, the first correspondence relationship is referred to based on the amount of carrier movement obtained by the estimation, and the number of prints (operating amount) corresponding to the film thickness reaching the life is determined by the photoconductor. It may be acquired as the life of the drum.

Further, the image forming apparatus may include an intermediate transfer belt on which a toner image formed by developing an electrostatic latent image is transferred. A part of the carrier moved to the photoconductor drum causes a dent on the peripheral surface of the intermediate transfer belt. The image forming apparatus stores the second correspondence relationship indicating the transition of the number of dents on the peripheral surface of the intermediate transfer belt with respect to the operating amount according to the amount of carrier movement caused by the manufacturing variation, and is obtained by estimation. The second correspondence relationship may be referred to based on the movement amount of the carrier, and the operating amount corresponding to the number of dents reaching the life may be acquired as the life of the intermediate transfer belt body.

Further, the image forming apparatus stores a third correspondence relationship indicating a change in the amount of carrier movement from the developer carrier to the photoconductor drum with respect to the amount of the developer conveyed in the developer carrier due to manufacturing variation. Therefore, the transport amount of the developer transported by the developer carrier may be estimated, and the transfer amount of the carrier corresponding to the transport amount of the developer obtained by the estimation may be obtained by referring to the third correspondence relationship. ..

Further, the image forming apparatus stores a fourth correspondence relationship indicating a change in a predetermined development bias applied to the developer carrier with respect to the amount of the developer transported by the developer carrier due to manufacturing variation. By switching the development bias applied to the developer carrier, the density of the toner image formed on the photoconductor is different. In the initial stage, the image forming apparatus develops an electrostatic latent image of a predetermined pattern, obtains a development bias having a predetermined toner concentration, refers to the fourth correspondence relationship, and corresponds to the obtained development bias. The amount of the developer transported may be obtained.

Further, the image forming apparatus shows a change in a predetermined development bias applied to the developer carrier with respect to the amount of the developer conveyed in the developer carrier due to manufacturing variation according to the environmental information that fluctuates depending on the environment. I remember the fifth correspondence. By switching the development bias applied to the developer carrier, the density of the toner image formed on the photoconductor drum is different. The image forming apparatus acquires environmental information, develops an electrostatic latent image of a predetermined pattern at an initial stage, obtains a development bias to obtain a predetermined toner concentration, and obtains a fifth correspondence according to the acquired environmental information. The amount of the developer corresponding to the obtained development bias may be obtained by referring to the relationship.

As described above, the image forming apparatus has an excellent effect that the life of the intermediate transfer belt 21 and the life of the photoconductor drum 23K included in the image forming apparatus can be predicted even when there are variations in manufacturing.

2 Other Modifications Although the present disclosure has been described based on the above-described embodiment, the present disclosure is not limited to the embodiment. It may be as shown below.

(1) In the above embodiment, the image forming apparatus 10 includes, but is not limited to, the intermediate transfer belt 21.

The image forming apparatus may not include an intermediate transfer belt and may employ a direct transfer method in which the toner image is directly transferred from the photoconductor drum to the recording sheet.

(2) In the above embodiment, when it is determined that the intermediate transfer belt 21 or the photoconductor drum 23K has reached the end of its useful life, the operation panel 19 requests replacement of the intermediate transfer belt 21 or the photoconductor drum 23K. it's shown. However, it is not limited to this.

For example, when it is determined that the number of prints on the intermediate transfer belt 21 or the photoconductor drum 23K has reached 90% of the life, the operation panel 19 prepares to replace the intermediate transfer belt 21 or the photoconductor drum 23K. The fact (the fact that the replacement time is approaching) may be displayed.

(3) As described above, the image forming apparatus is a computer system including a microprocessor and a memory. The memory stores the computer program, and the microprocessor may operate according to the computer program.

The microprocessor is composed of a fetch unit, a decoding unit, an execution unit, a register file, an instruction counter, and the like. The fetch unit reads one instruction code included in the computer program from the computer program stored in the memory. The decoding unit decodes the read instruction code. The execution unit operates according to the decoding result. In this way, the microprocessor operates according to the computer program stored in the memory.

Here, a computer program is configured by combining a plurality of instruction codes indicating instructions to a computer in order to achieve a predetermined function.

Further, the computer program may be recorded on a computer-readable recording medium such as a flexible disk, a hard disk, an optical disk, or a semiconductor memory.

Further, the computer program may be transmitted via a wired or wireless telecommunication line, a network typified by the Internet, data broadcasting, or the like.

(4) The above-described embodiment and the above-described modification may be combined.

The image forming apparatus according to the present disclosure has an excellent effect of being able to predict the life of the photoconductor included in the individual image forming apparatus even when there are variations during manufacturing, and has two components. It is useful as a technique for forming an image by an electrophotographic method using a system developer.

10 Image forming device 11 Image reader 12 Printer 13 Paper feeding unit 14 Image forming unit 15 Discharge tray 19 Operation panel 20Y to 20K Image forming unit 21 Intermediate transfer belt 22 Secondary transfer roller 23K Photoreceptor drum 24K Charged charger 25K LED array 26K Development Printer 27K Developer carrier 28K Primary transfer roller 29K Gap 30K Development position 31K Blade 32K Regulator 41 Humidity sensor 42 Concentration sensor 50 Fixing part 51 Heating roller 52 Pressurizing roller 60-62 Paper feed cassette 63-65 Pickup roller 100 Control circuit 101 CPU
101a Main control unit 102 ROM
103 RAM
104 Image memory 105 Image processing circuit 106 Network communication circuit 107 Scanner control circuit 108 Input / output circuit 109 Printer control circuit 111 Printer main control circuit 112 Life acquisition circuit 113 Storage circuit

Claims (10)

An image forming apparatus that develops an electrostatic latent image on the surface of a photoconductor with toner conveyed by a developer carrier that carries a developer containing toner and carriers.
A memory that stores the first correspondence relationship indicating a change in the film thickness of the photoconductor with respect to the operating amount of the image forming apparatus according to the amount of movement of the carrier from the developer carrier to the photoconductor due to manufacturing variation. Means and
In the initial stage of use of the image forming apparatus, an estimation means for estimating the amount of carrier movement and
The feature is that the first correspondence relationship is referred to based on the movement amount of the carrier obtained by estimation, and an acquisition means for acquiring the working amount corresponding to the film thickness reaching the life as the life of the photoconductor is provided. Image forming device. Further, an intermediate transfer body on which the toner image formed by developing the electrostatic latent image is transferred is provided.
A part of the carrier that has moved to the photoconductor causes a dent on the peripheral surface of the intermediate transfer material.
The storage means further stores a second correspondence relationship indicating a transition of the number of dents of the carrier on the peripheral surface of the intermediate transfer body with respect to the operating amount according to the amount of movement of the carrier due to the manufacturing variation.
The acquisition means further refers to the second correspondence relationship based on the movement amount of the carrier obtained by estimation, and acquires the operating amount corresponding to the number of dents reaching the life as the life of the intermediate transfer member. The image forming apparatus according to claim 1. The storage means further stores a third correspondence relationship indicating a change in the amount of carrier transfer from the developer carrier to the photoconductor with respect to the amount of the developer transported in the developer carrier due to manufacturing variations. And
The estimation means
In the initial stage, a sub-estimating means for estimating the amount of the developer transported by the developer carrier, and
The image according to claim 1 or 2, further comprising a movement amount acquisition means for acquiring a movement amount of a carrier corresponding to a transport amount of the developer obtained by referring to the third correspondence relationship. Forming device. The storage means further stores a fourth correspondence relationship indicating a change in a predetermined development bias applied to the developer carrier with respect to the amount of the developer conveyed by the developer carrier due to manufacturing variations. Ori,
By switching the development bias applied to the developer carrier, the density of the toner image formed on the photoconductor is different.
The sub-estimation means
In the initial stage, a development bias acquisition means for developing an electrostatic latent image of a predetermined pattern to obtain a development bias to obtain a predetermined toner concentration, and
The image forming apparatus according to claim 3, further comprising a transport amount acquisition means for acquiring a transport amount of the developer corresponding to the obtained development bias with reference to the fourth correspondence relationship. The storage means further changes in a predetermined development bias applied to the developer carrier with respect to the amount of the developer transported by the developer carrier due to manufacturing variations in response to environmental information that varies depending on the environment. Remembers the fifth correspondence that indicates
By switching the development bias applied to the developer carrier, the density of the toner image formed on the photoconductor is different.
The sub-estimation means
Environmental information acquisition means for acquiring environmental information and
In the initial stage, a development bias acquisition means for developing an electrostatic latent image of a predetermined pattern to obtain a development bias to obtain a predetermined toner concentration, and
The third aspect of claim 3, wherein the transport amount acquisition means for acquiring the transport amount of the developer corresponding to the obtained development bias is included with reference to the fifth correspondence relationship according to the acquired environmental information. Image forming device. The image forming apparatus according to claim 1, further comprising a correction means for correcting the life of the acquired photoconductor according to the usage status of the photoconductor. The image forming apparatus according to claim 6, wherein the correction means corrects when a jam in the recording sheet occurs. The image forming apparatus according to claim 2, further comprising a correction means for correcting the life of the acquired intermediate transfer body according to the usage status of the intermediate transfer body. The image forming apparatus according to claim 8, wherein the correction means corrects when a jam in the recording sheet occurs. A control method used in an image forming apparatus that develops an electrostatic latent image on the surface of a photoconductor with toner conveyed from a developer carrier that carries a developer composed of toner and a carrier.
The image forming apparatus stores the first correspondence relationship indicating a change in the film thickness of the photoconductor with respect to the operating amount of the image forming apparatus according to the amount of movement of the carrier to the photoconductor due to manufacturing variation.
The control method is
In the initial stage of use of the image forming apparatus, an estimation step of estimating the amount of carrier transfer from the developer carrier to the photoconductor, and an estimation step.
The feature is that the first correspondence relationship is referred to based on the movement amount of the carrier obtained by estimation, and the working amount corresponding to the film thickness reaching the life is included as the life of the photoconductor, and the acquisition step is acquired. Control method to do.

Images