JP5440247B2 - Image forming apparatus, maintenance management system for image forming apparatus, developer life calculation method, developer life calculation program, and storage medium - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine or a laser printer, and more specifically, an image forming apparatus that appropriately determines a developer life by predicting a deterioration state of a developer from information on accumulated printing conditions. The present invention relates to an image forming apparatus maintenance management system, a developer life calculation method, a developer life calculation program, and a storage medium.

In an image forming apparatus using a two-component developer composed of a toner and a carrier, the life of the developer is determined by the deterioration of the carrier over time. Therefore, the developer should be replaced on the condition that a predetermined number of sheets have been printed. Often set. There are various types of carrier deterioration with time. For example, toner or a toner external additive adheres to the surface of the carrier and the charging ability decreases, or the carrier surface wears down and the carrier resistance decreases. The carrier film is scraped off. The state of deterioration of these carriers with time varies greatly depending on the image area ratio in the printing operation and the conditions such as whether the printing operation is continuous or intermittent. For this reason, if the lifetime of the developer is uniformly determined based on the number of printed sheets, there is a waste that the developer must be replaced even though the lifetime has not yet been reached.
In order to solve the above-described problem, Patent Document 1 discloses a technique for detecting the volume of a developer, predicting the deterioration state of toner and developer from the detection result, and predicting the replacement time of the developer. Yes.
Further, Patent Document 2 uses that the toner density is lower in the control of keeping the image density constant because the charging ability of the carrier is lowered and the charge amount of the toner is lowered when the developer is deteriorated. An invention for predicting the deterioration state of the developer is disclosed. In the present invention, the state in which the toner density is lower than a certain amount is judged from the image patch density in a very strong developing electric field, thereby predicting the deterioration state of the developer and the replacement time.
Further, Patent Document 3 discloses a technique for measuring the electrostatic capacity of the developer on the developing sleeve, predicting the deterioration state of the developer from the measurement result, and predicting the replacement time of the developer.
If the deterioration state of the developer can be correctly detected by the techniques described in Patent Documents 1 to 3, matching between the deterioration state of the developer and the replacement time of the developer can be achieved. That is, by using the developer just before the end of its life, it is possible to replace the developer without waste, and it is possible to realize cost reduction and environmental load reduction.

However, since the technique disclosed in Patent Document 1 is greatly affected by the change in the bulk of the developer due to the environmental change, there is a difference between the actual deterioration state of the developer and the predicted deterioration state of the developer. There is a problem that will occur.
Further, in the technique disclosed in Patent Document 2, since a decrease in toner density in a high-humidity environment is not considered, when the environmental fluctuation is large, the actual developer deterioration state and the predicted developer There is a problem that a deviation occurs in the deterioration state.
Further, the technique disclosed in Patent Document 3 has a disadvantage that if a mechanism for measuring the electrostatic capacity of the developer is provided, the developing device is enlarged and the cost is increased. Also, since there is no good correlation between the decrease in carrier charging ability and the change in capacitance due to the addition of the additive released from the toner to the carrier surface, the actual developer deterioration state was predicted. There is a problem that a deviation occurs in the deterioration state of the developer.
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a method that is less susceptible to environmental fluctuations, in which a developer deterioration state is predicted from accumulated printing conditions. To provide an image forming apparatus that matches the deterioration state of the developer with the actual developer life by calculating the life of the developer, reduces waste, reduces cost, and reduces environmental impact. is there.

In order to solve the above problems, an invention according to claim 1 is an image forming apparatus for developing a latent image on a latent image carrier with a two-component developer comprising toner and a carrier, and is a cumulative print page. A counting means for counting the number of pages and the number of continuous print pages per job, an image area ratio calculating means for calculating an image area ratio per page printed on a recording medium, and a cumulative print page number counted by the counting means Average image area ratio calculating means for calculating an average image area ratio per page based on the image area ratio calculated by the image area ratio calculating means, and continuous print pages per job counted by the counting means. based on the number, the average duty calculating means for calculating the average number of continuous printing of pages, and the average image area ratio and the average continuous printing number of pages in per job, the developer And wherein the correction coefficient deriving means for deriving a correction factor for life reference value, a developer life calculating means for calculating the developer life by multiplying the correction coefficient to the developer life reference value, an image forming apparatus comprising To do .

According to a second aspect of the present invention, when the image area ratio is equal to or less than a predetermined threshold value, an image area ratio difference determination for calculating a toner amount corresponding to a difference between the threshold value and the image area ratio. comprising means, and wherein the image forming apparatus according to claim 1, wherein the adjusting toner pattern for consuming toner calculated amount of the image area ratio difference determining means for forming the latent image bearing member.
The invention according to claim 3, wherein the adjusting toner pattern, wherein the image forming apparatus of claim 2, wherein the formed outside the transfer area.
According to a fourth aspect of the present invention, there is provided the image forming apparatus according to any one of the first to third aspects, a service terminal that manages maintenance / inspection information of the image forming apparatus, the image forming apparatus, and the service terminal. And the image forming apparatus is characterized by a maintenance management system for the image forming apparatus that transmits the developer life calculated by the developer life calculating means to the service terminal.

According to a fifth aspect of the present invention, there is provided a developer life calculation method in an image forming apparatus for developing a latent image on a latent image carrier with a two-component developer comprising a toner and a carrier, wherein the counting means is a cumulative print page. The step of counting the number of pages and the number of continuous print pages per job, the step of calculating the image area ratio per page printed on the recording medium by the image area ratio calculating means, and the average image area ratio calculating means A step of calculating an average image area ratio per page based on the cumulative number of printed pages counted by the means and the image area ratio calculated by the image area ratio calculating means; and an average duty calculating means comprising: based on the continuous printing number of pages per job count, calculating the average number of continuous printing pages in per job, the correction coefficient deriving means The average image area ratio and the average continuous printing number of pages, and deriving a correction factor for the developer life reference value, the developer life calculating means, by multiplying the correction coefficient to the developer life reference value And a developer life calculation method comprising: calculating a developer life.
The invention according to claim 6, characterized by the developer life calculation program for executing the developer life calculation method according to claim 5, wherein the computer.
A seventh aspect of the invention is characterized by a computer-readable storage medium in which the developer life calculation program of the sixth aspect is recorded.

  According to the present invention, the lifetime of the carrier in the two-component developer over time is predicted from the image area ratio in the printing operation and the average number of continuously printed pages per job, and the developer life is calculated. Actually, it is possible to reduce waste that the developer must be replaced even though the developer life has not been reached, and it is possible to achieve cost reduction and environmental load reduction.

1 is a schematic configuration diagram illustrating a printer according to an embodiment. A schematic cross-sectional view of a process unit as image forming means is shown. FIG. 3 is a diagram illustrating a control unit of the image forming apparatus according to the present invention. It is a figure which shows the relationship between the average image area ratio A and developer lifetime which concerns on 1st embodiment. It is a figure which shows the relationship between average dutyB and developer lifetime which concern on 1st embodiment. It is a table which shows the developer lifetime correction coefficient which concerns on 1st embodiment. It is a figure which compares the cumulative number of printed sheets until the developer replacement in the first embodiment and the conventional example. It is a figure which shows the relationship between the average image area ratio A and developer lifetime which concerns on 2nd embodiment. 10 is a table showing developer life correction coefficients according to the second embodiment. It is a figure which shows the cumulative number of printed sheets until the developer replacement in the second embodiment and the conventional example. It is a figure which shows the relationship between the average image area ratio A and developer lifetime which concerns on 3rd embodiment. 10 is a table showing developer life correction coefficients according to a third embodiment. It is a figure which shows the cumulative number of printed sheets until the developer replacement in the third embodiment and the conventional example. It is a figure which shows the maintenance management system of the printer which concerns on 4th embodiment.

Hereinafter, an embodiment of an electrophotographic printer (image forming apparatus) will be described as an image forming apparatus to which the present invention is applied.
First, a basic configuration of the printer according to the present embodiment will be described with reference to FIG. FIG. 1 is a schematic configuration diagram illustrating a printer according to the present embodiment.
The printer 1 is disposed at the lowermost part of the printer 1, and includes a first paper cassette 11 and a second paper cassette 15 that store recording paper P as a recording medium, and recording paper P one by one from a bundle of recording paper P. And the first paper feed roller 13 and the second paper feed roller 17 that feed the paper to a paper feed path 19 formed in a substantially vertical direction, and the recording paper P that is disposed in the paper feed path 19 is conveyed. A secondary transfer nip N <b> 2 is formed between the plurality of conveying roller pairs 21, the registration roller pair 23 that abuts the recording paper P that has been conveyed and stops temporarily to take the image transfer timing, and the belt driving roller 53. Thus, a fixing unit 27 that includes a secondary transfer roller 25 that transfers the toner image onto the recording paper P, a pressure roller 29, and a fixing roller 31, and that fixes the toner image onto the recording paper P by heat and pressure, and a fixing roller. 31 electromagnetic induction An IH coil unit 33 that generates heat in the heat layer, a discharge roller pair 37 that is disposed in the discharge path 35 and discharges the recording sheet P to the outside of the printer 1, and the recording sheet P discharged to the outside of the printer 1 A stack unit 39 that stacks and a double-sided path 41 that reverses the recording paper P having a toner image fixed on one side thereof are provided.

In addition, the printer 1 is disposed below the process unit 100 (100Y, 100C, 100M, 100K) that forms a toner image for each color, and the photosensitive member 111 (111Y, 111C, 111M, 111K), an exposure unit 43 for writing a latent image, an intermediate transfer belt 47 to which a toner image formed by the process unit 100 is transferred, a belt cleaning unit 49 for cleaning the intermediate transfer belt 47, and the surface of the photoreceptor 111 A primary transfer roller 51 (51Y, 51C, 51M, 51K) for transferring the formed toner image to the intermediate transfer belt, a belt driving roller 53 for driving the intermediate transfer belt 47, and a belt tension roller for adjusting the tension of the intermediate transfer belt 47 Intermediate transfer unit 4 with 55 A waste toner bottle 57 which is disposed below the intermediate transfer unit 45 and accommodates the transfer residual toner removed from the intermediate transfer belt 47 by the belt cleaning unit 49; Toner bottle 59 (59Y, 59C, 59M, 59K).
The printer 1 also includes control means (not shown) that controls the entire apparatus of the printer 1.
The printer 1 shown in FIG. 1 includes four process units 100Y, 100C, 100M, and 100K for yellow, cyan, magenta, and black (hereinafter referred to as Y, C, M, and K) as process units 100 that are toner image forming units. It has. In these, Y, C, M, and K toners of different colors are used as image forming substances for forming an image, but the other configurations are the same.

FIG. 2 is a schematic cross-sectional view of a process unit as image forming means. The process unit 100 includes a photoconductor unit 110 including a photoconductor 111 and a developing unit 130 that develops the photoconductor 111. The photoconductor unit 110 and the developer unit 130 can be attached to and detached from the printer 1 main body.
The photoconductor unit 110 includes a drum-shaped photoconductor 111 serving as a latent image carrier, a drum cleaning device 113 serving as a latent image carrier cleaning unit that removes and collects transfer residual toner attached to the photoconductor 111, and the like. Lubricant application brush 117 and lubricant 119 (zinc stearate) for making the surface friction coefficient a predetermined value, lubricant application blade 121 for uniformly applying the lubricant 119 on the photoconductor 111, and the photoconductor 111 are uniformly charged. A charging roller 123 for cleaning the charging roller, a charging roller cleaner 125 for cleaning the charging roller 123, and the like.
The drum cleaning device 113 includes a cleaning blade 115 that removes transfer residual toner and the like attached to the photoconductor 111.
The charging roller 123 applies a charging bias obtained by superimposing a DC voltage on an AC voltage from a charging bias applying unit (not shown) to the surface of the photosensitive member 111 that is rotated in a clockwise direction (arrow A direction) in the drawing by a driving unit (not shown). To charge uniformly. Subsequently, exposure scanning is performed with a laser beam L emitted from an exposure unit 43 (see FIG. 1) corresponding to the image signal to form an electrostatic latent image.

The developing unit 130 includes a first developer accommodating portion 131 in which the first conveying screw 133 is disposed, and a second developer accommodating portion 135 in which the second conveying screw 137 is disposed. A toner concentration sensor 139 including a magnetic permeability sensor is installed on the lower surface of the agent container 131, and the mixing ratio between the carrier particles, which are magnetic materials, and the toner is calculated from the magnetic permeability so as to obtain a predetermined toner concentration. The toner is replenished as necessary from a toner replenishing device (not shown).
The first conveying screw 133 is rotationally driven by a driving means (not shown), and the developer in the first developer accommodating portion 131 is conveyed from the back side to the near side in the direction orthogonal to the paper surface of FIG. It enters the second developer accommodating portion 135 through a communication port (not shown) provided in the partition wall 141 between the accommodating portion 131 and the second developer accommodating portion 135.
The second conveying screw 137 in the second developer accommodating portion 135 is rotationally driven by a driving means (not shown) to convey the developer from the near side to the far side in the direction orthogonal to the paper surface of FIG. Above the second conveying screw 137, a developing sleeve 143 is arranged in a posture parallel to the second conveying screw 141, and the developing sleeve 143 as a developer carrying member rotates counterclockwise (arrow B direction) in the figure. Driven.
The developing sleeve 143 is made of a nonmagnetic material (aluminum) pipe, and the surface is roughened by sandblasting. A magnet (not shown) is disposed inside the developing sleeve 143, and a part of the developer conveyed by the second conveying screw 137 is pumped up to the surface of the developing sleeve 143 by the magnetic force generated by the magnet. Then, after the layer thickness is regulated by a doctor blade 145 disposed so as to maintain a predetermined gap with the developing sleeve 143, the layer thickness is conveyed to a developing region facing the photosensitive member 111, and from a developing bias applying unit (not shown). The toner is attached to the electrostatic latent image formed on the photoconductor 111 by the developing bias applied to the developing sleeve 143 to form a toner image. The developer that has consumed toner by development is returned to the second conveying screw 137 as the developing sleeve 143 rotates. Then, when the sheet is conveyed to the back side in the direction orthogonal to the paper surface of FIG. 2, the sheet returns to the first developer accommodating portion 131 through a communication port (not shown).

  The result of detecting the magnetic permeability of the developer by the toner density sensor 139 is sent to a control means (not shown) as a voltage signal. Since the magnetic permeability of the developer has a correlation with the toner concentration of the developer, the toner concentration sensor 139 outputs a voltage having a value corresponding to the toner concentration. The control means includes information storage means such as RAM (Randam Access Memory), in which Vref, which is a target value of the output voltage from the toner density sensor 139, is stored and output from the toner density sensor 139. The voltage value is compared with Vref, and a toner amount corresponding to the comparison result is supplied from a toner supply device (not shown) from the back side in the direction perpendicular to the paper surface of FIG. 2 of the first developer accommodating portion 131 in the developing unit 130. The toner concentration in the developer is maintained at a desired value. This control by the toner density sensor 139 and the toner supply device is performed for each color individually.

As shown in FIG. 1, an exposure unit 43 is disposed below the process unit 100 in the drawing. The exposure unit 43 serving as a latent image writing unit irradiates the surface of the photosensitive member 111 of each process unit 100 with a laser beam L based on the image information. Thereby, an electrostatic latent image is formed on the photosensitive member 111. The exposure unit 43 irradiates the photosensitive member 111 with a laser beam L emitted from a laser diode (not shown) as a light source. The laser light L emitted from the laser diode is scanned by a polygon mirror that is rotationally driven by a motor, and reaches the photosensitive member 111 via a plurality of optical lenses and mirrors. Instead of such a configuration, exposure means using an LED array may be employed.
Below the exposure unit 43, a first paper feed cassette 11 and a second paper feed cassette 15 are arranged side by side in the vertical direction. Each of these paper feed cassettes contains a recording paper P as a recording medium, and the first paper feed roller 13 and the second paper feed roller 17 are in contact with the uppermost recording paper P, respectively. . When the paper feed roller is driven to rotate counterclockwise (in the direction of arrow C) in FIG. 1 by a driving means (not shown) at a predetermined timing, the recording paper P is in a substantially vertical direction on the right side of the paper feed cassette in the figure. The sheet is discharged toward the sheet feeding path 19 disposed in the area. A plurality of conveying roller pairs 21 are arranged in the sheet feeding path 19, and the recording paper P sent to the sheet feeding path 19 is conveyed upward by these conveying roller pairs 21.

A registration roller pair 23 is disposed in the paper feed path 19. The registration roller pair 23 temporarily stops the recording paper P conveyed by the conveyance roller pair 21. The registration roller pair 23 is driven in accordance with the timing at which the toner image formed on the intermediate transfer belt 47 reaches the secondary transfer nip N2 formed between the intermediate transfer belt 47 and the secondary transfer roller 25. Then, the recording paper P is sent out toward the secondary transfer nip N2.
Above each process unit 100 in the figure, an intermediate transfer unit 45 is arranged to endlessly move the intermediate transfer belt 47, which is an endless moving body, in the counterclockwise direction (arrow D direction) in the figure. . In addition to the intermediate transfer belt 47, the intermediate transfer unit 45 serving as a transfer unit includes a belt cleaning unit 49, a primary transfer roller 51 (51Y, 51C, 51M, 51K) disposed at a position facing the photoconductor 111 of each color, an external The belt drive roller 53, the belt tension roller 55, and the like that drive the intermediate transfer belt 47 in response to the drive from the belt. The belt drive roller 53 also serves as a counter roller for the secondary transfer roller 25.
While being stretched by these rollers, the intermediate transfer belt 47 is moved endlessly by the rotational drive of the belt driving roller 53.

The primary transfer roller 51 is in contact with the photoconductor 111 via the intermediate transfer belt 47 to form a primary transfer nip N1 (see FIG. 2). The toner image on the photoconductor 111 is transferred onto the intermediate transfer belt 47 by applying to the primary transfer roller 51 a transfer bias having the opposite polarity to the toner of the toner image formed on the photoconductor 111. The toner images of the respective colors formed by the process units 100 of the respective colors are sequentially primary-transferred onto the intermediate transfer belt 47, and a color image is formed on the intermediate transfer belt 47.
The secondary transfer roller 25 is disposed outside the intermediate transfer belt 47 and at a position facing the belt driving roller 53 and the intermediate transfer belt 47 across the belt. The secondary transfer roller 25 abuts against the belt driving roller 53 with a predetermined load by a spring load, and a secondary transfer nip N2 is formed.
The color image formed on the intermediate transfer belt 47 moves to the secondary transfer nip N2 by the endless movement of the intermediate transfer belt 47. The registration roller pair 23 is driven in synchronization with the color image carried on the intermediate transfer belt 47 entering the secondary transfer nip N2, and causes the recording paper P to enter the secondary transfer nip N2.
The toner image is secondarily transferred onto the recording paper P by a secondary transfer electric field and a nip pressure formed between the secondary transfer roller 25 and the belt driving roller 53. The electric field for secondary transfer is formed by applying a transfer bias having the same polarity as the toner to the belt driving roller 53 and grounding the secondary transfer roller 25.

A small amount of toner that has not been transferred to the recording paper P remains on the intermediate transfer belt 47 after passing through the secondary transfer nip N2. This is cleaned by the belt cleaning unit 49. The belt cleaning unit 49 has a cleaning blade 50 that comes into contact with the surface of the intermediate transfer belt 47, and the transfer residual toner on the intermediate transfer belt 47 is scraped and removed by the cleaning blade 50.
The transfer residual toner removed from the intermediate transfer belt 47 is accommodated in a waste toner bottle 57 and discarded.
A fixing unit 27 is disposed downstream (upward) of the secondary transfer nip N2 in the recording paper P conveyance direction. The fixing unit 27 includes a fixing roller 31 that includes an electromagnetic induction heat generating layer, a pressure roller 29 that is in contact with the fixing roller 31 with a predetermined pressure to form a predetermined nip width, a temperature sensor (not shown), and the like. . On the left side of the fixing roller 31 in the figure, there is an IH coil unit 33 which is an electromagnetic induction means for generating heat in the electromagnetic induction heat generating layer in the fixing roller 31. The fixing roller 31 is heated by electromagnetic induction by an IH coil. The pressure roller 29 rotates in a clockwise direction (arrow E direction) and the fixing roller 31 rotates in a counterclockwise direction (arrow F direction) by a drive source (not shown).
The recording paper P that has passed through the secondary transfer nip N 2 is separated from the intermediate transfer belt 47 and then conveyed into the fixing unit 27. Then, in the process of being conveyed from the lower side to the upper side in the figure while being sandwiched by the fixing nip N3 of the fixing unit 27, the toner image is heated by the fixing roller 31 and simultaneously pressurized by the fixing nip N3, so that the toner image is printed on the recording paper P. Fixed on top.

The recording paper P thus subjected to the fixing process is discharged out of the printer 1 via the discharge roller pair 37 and is stacked on the stack unit 39 formed on the upper surface of the printer 1 main body.
Above the intermediate transfer unit 45, toner bottles 59 (59Y, 59C, 59M, and 59K) for each color that store Y, C, M, and K toners are disposed. The toner of each color stored in the toner bottle 59 is appropriately supplied to the developing unit 130 of the process unit 100 of each color. These toner bottles 59 can be detached from the main body of the printer 1, and the toner bottle 59 can be replaced when the toner remaining in the toner bottle 59 runs out.

[First embodiment]
A first embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a diagram showing the control means of the image forming apparatus according to the present invention. FIG. 4 is a diagram showing the relationship between the average image area ratio A and the developer life according to the present embodiment. FIG. 5 is a diagram showing a relationship between the average duty B and the developer life according to the present embodiment. FIG. 6 is a table showing developer life correction coefficients according to the present embodiment.
In this embodiment, a correction coefficient for calculating the life of the developer is obtained from the cumulative number of printed pages, the image area ratio, and the number of continuous printed pages per job, and this correction coefficient is used as a reference value for the developer life. By multiplying, the characteristic is that the developer life closer to the actual life of the developer is calculated.
In the present embodiment, the Ricoh Imagio MPC4500 is used as the printer 1 (image forming apparatus). The printing speed of this apparatus is 35 sheets / minute (A4Y), and the process speed is 205 mm / s. In addition, the Example shown below is one Embodiment of this invention, and is not the meaning which limits the timing of a process control, a control method, etc.

As illustrated in FIG. 3, the control unit 200 according to the present embodiment counts the cumulative print page number C, the duty Bj that is the number of continuous print pages per continuous print operation (one job), and the total job number J. Means 201, image area ratio calculating means 202 for calculating the image area ratio Ap of the recording paper P (recording medium) for each page, and the cumulative number of printed pages C and the image area ratio Ap of each page. An average image area ratio calculating means 203 for calculating an average value of the image area ratios (average image area ratio A), an average duty calculating means 204 for calculating an average dutyB indicating the average value of the number of continuously printed pages per job, A correction coefficient deriving means 206 for deriving a correction coefficient (a, b) for the reference value of developer life (developer life reference value D) from the average image area ratio A and average duty B; The number comprises (a, b) and the developer life calculating means 207 for calculating a developer life X indicate when to replace the developer from the developer life reference value D, and. The control unit 200 includes a storage unit 205 including a non-volatile memory that stores the cumulative print page number C, duty Bj, total job number J, image area ratio Ap, average image area ratio A, average duty B, and correction coefficient. Yes.
The developer life is a value based on the cumulative number of printed pages. The developer life reference value D is the cumulative number of printed pages in which the developer has reached the end of life when printing is continued under predetermined conditions, and is calculated in advance through experiments. The developer life X is the cumulative number of printed pages indicating the developer life required by the present invention.

The operation of each unit included in the control unit 200 and a method for deriving the developer life X using each unit will be described below.
The counting unit 201 counts the cumulative print page number C, the duty Bj that is the number of continuous print pages per continuous print operation (one job), and the total job number J (counting step).
The counting unit 201 counts up by one each time printing is performed in order to calculate the cumulative print page number C. Here, the term “one-time printing” refers to printing on one side of the recording paper P. When printing on both sides of the recording paper P, the counting unit counts printing on the front side and printing on the back side, and thus counts up twice.
The printer 1 according to the present embodiment includes a monochrome mode and a full color mode as print modes. The monochrome mode is an operation mode of the printer 1 in which only the process unit 100K operates, and the full color mode is an operation mode of the printer 1 in which the process units 100 of all four colors operate. The counting means 201 counts the cumulative number of printed pages Cm in the monochrome mode and the cumulative number of printed pages Cc in the full color mode. Therefore, the cumulative print page number Ck of the process unit 100K is equal to the cumulative print page number Cm plus the cumulative print page number Cc (Ck = Cm + Cc). Further, the cumulative print page numbers Cma, Ccy, and Cye of the process units 100M, 100C, and 100Y are equal to the cumulative print page number Cc, respectively. The accumulated print page numbers Cm and Cc counted by the counting unit 201 are stored in the storage unit 205, respectively. Since the calculation method of the developer life in each process unit is the same, in the following description, the cumulative print page number Ck, Cma, Ccy, and Cye are typically expressed as the cumulative print page number C.

The image area ratio calculating means 202 calculates the image area ratio Ap of the recording paper P (recording medium) for each page and stores it in the storage means 205 (image area ratio calculating step).
The average image area ratio calculation unit 203 reads the cumulative print page number C from the storage unit 5, calculates the average value (average image area ratio A) of the image area ratio Ap in the cumulative print page number C, and stores it in the storage unit 205. Store (average image area ratio calculation step).
The average duty calculation unit 204 defines one continuous printing as one job, reads the duty Bj and the total job number J of each job from the storage unit 5, and accumulates print pages from the duty Bj and the total job number J. An average duty B that is an average value of the number of continuously printed pages in the number C is calculated and stored in the storage unit 205 (average duty calculating step). The duty is information indicating whether printing is performed continuously or intermittently.

The correction coefficient deriving unit 206 derives a correction coefficient a corresponding to each average image area ratio A and a correction coefficient b corresponding to each average duty B from the developer life reference value D and FIGS. 4 and 5.
Here, a method of determining the reference developer life reference value D will be described. When the developer reaches the end of its life, (1) when the external additive detached from the toner covers the carrier, the charging ability of the carrier is lowered, and the charge amount of the toner becomes a predetermined threshold value or less. (2) The carrier surface film is abraded and the resistance of the carrier is reduced, and the amount of carrier adhering to the photosensitive drum due to the carrier being charged with the opposite polarity due to the charge injected into the carrier is a predetermined threshold value. This is the case. The developer life reference value D is determined by experimentally obtaining the cumulative number of printed pages when at least one of (1) and (2) is satisfied. In this embodiment, when an experiment was performed under the conditions of an image area ratio of 5 [%] and a duty of 5 [page / job], the developer life reference value D was 450,000 pages. Note that the developer life reference value D is a numerical value that varies depending on experimental conditions, and 450,000 pages in the present embodiment is merely an example.

As shown in FIG. 4, the developer life varies depending on the average image area ratio A. Further, as shown in FIG. 5, when the duty changes, the toner consumption with respect to the unit driving time of the process unit changes, so that the developer life also changes depending on the duty.
Derivation of the correction coefficient a and the correction coefficient b will be described.
The correction coefficient deriving unit 206 derives, as a correction coefficient a, the ratio of the developer life in each average image area ratio when the developer life in the printing conditions when the developer life reference value D is determined is 1. The ratio of the developer life at each average duty B is derived as a correction coefficient b (correction coefficient deriving step).
In this embodiment, the correction coefficient “a” is derived from the correction coefficient “a” and “b”, where the developer life at an average image area ratio of 5% is 1. FIG. 6 shows the correction coefficients created by dividing the image area ratio A into 8 and deriving 8 correction coefficients a, and dividing the average duty B into 5 and deriving 8 correction coefficients b. A table is shown. In this manner, a table obtained by dividing the correction coefficients a and b into predetermined sections in advance may be created, and the correction coefficients a and b may be determined based on this table.

The developer life calculation means 207 calculates the developer life X (developer life calculation step). The developer life calculating means 207 calculates the developer life X as D × a × b, that is,
X [page] = 450,000 [page] × a × b
(1)
It has been decided. Also, the cumulative print page number C and developer life X are
C [page] ≥ X [page]
(2)
Is satisfied, it is determined that it is time to replace the developer.
Conventionally, the cumulative number of printed pages used to determine the developer life has been determined assuming that printing is continued under the most severe conditions. However, in practice, it is difficult to think that the assumed conditions are continuous, and the developer has to be replaced even if the life has not actually been reached. In this embodiment, the deterioration state of the developer and the developer life are matched, and the cumulative number of printed pages closer to the actual developer life is determined as the developer life. Can be reduced.

  FIG. 7 shows a comparison of the number of pages printed until the developer replacement in this embodiment and the conventional example when repeated printing is performed under conditions of an average image area ratio of 5 [%] and an average duty of 5 [pages / jobs]. It is a figure to do. In the present embodiment, the cumulative number of printed pages until the developer replacement is increased, and the developer can be used without waste.

As described above, according to the present embodiment, the lifetime of the developer in the two-component developer is predicted from the image area ratio in the printing operation and the average number of continuously printed pages per job, and the developer life is thereby increased. Therefore, it is possible to reduce waste that the developer must be replaced even though the developer life has not actually been reached, and to achieve cost reduction and environmental load reduction.
Note that the method for calculating the developer life X shown in the present embodiment may be realized by a program that causes a computer to execute the method. Further, the program can be distributed by storing it in a computer-readable storage medium such as a CD-ROM.

[Second Embodiment]
A second embodiment of the present invention will be described based on FIG. 3, FIG. 8, and FIG. FIG. 8 is a diagram showing the relationship between the average image area ratio A and the developer life according to the present embodiment. FIG. 9 is a table showing developer life correction coefficients according to the present embodiment. The present embodiment is characterized in that when the image area ratio per page is equal to or less than a predetermined threshold, toner corresponding to the difference from the threshold is consumed. Hereinafter, the description of the same parts as those of the first embodiment is omitted.
In the printer 1 according to the present embodiment, as shown in FIG. 6, the correction coefficient a when the average image area ratio A is 5 [%] is the maximum value 1, and the developer life is the longest. Therefore, in this embodiment, 5%, which is the average image area ratio A with the longest developer life, is determined as the threshold value E. Note that the method of determining the threshold value E in the present embodiment is merely an example, and may be determined by another method.
The control unit 210 in the present embodiment further includes an image area ratio difference determination unit 211 (hereinafter referred to as a difference determination unit 211) in addition to the control unit 200 in the first embodiment. The difference determination unit 211 compares the threshold value E with the actual image interview rate Ap, and when the image area ratio Ap is equal to or less than the threshold value E (Ap ≦ E), the toner corresponding to the difference is obtained. Calculate the amount. The printer 1 forms a toner pattern (adjustment toner pattern) that can consume a toner amount corresponding to the difference on the photosensitive member 111 (see FIG. 2), and calculates the best image area ratio and the actual toner consumption amount. We are trying to match.
This adjustment toner pattern is formed in an inter-paper area between the printing operation in which the image area ratio Ap is equal to or less than the threshold value E and the next printing operation, that is, an area not transferred to the transfer paper P (outside the transfer area) It is formed and consumes toner. Note that this toner consumption may be performed not for each page but for each predetermined number of pages or for each job. Further, the adjustment toner pattern may be formed at a place other than the inter-paper area. For example, an adjustment toner pattern may be formed on the photoconductor 111 after a certain job is finished, and the toner pattern may be cleaned without printing.

In the graph of FIG. 8, it can be seen that the developer life at the image area ratio equal to or lower than the threshold is improved as compared with the graph of FIG. When the toner consumption is low, the developer is continuously agitated under a condition where the toner balance is low, so that there is a problem that the carrier wears quickly and the life of the developer is shortened due to a decrease in the resistance of the carrier. In this embodiment, when the image area ratio is 5% or less, the toner is consumed by forming the difference image area ratio patch so that the toner consumption is 5%. Life is getting longer.
The correction coefficient a in the present embodiment is derived based on FIG. Note that the calculation methods of the correction coefficient a, the correction coefficient b, the developer life reference value D, and the developer life X are the same as those in the first embodiment, and thus description thereof is omitted.

  FIG. 10 compares the cumulative number of pages printed until the developer replacement in this embodiment and the conventional example when repeated printing is performed under the conditions of an average image area ratio of 5 [%] and an average duty of 5 [page / job]. It is a figure to do. In the present embodiment, the cumulative number of printed pages until the developer replacement is increased, and the developer can be used without waste.

As described above, according to the present embodiment, when the image area ratio per page is equal to or smaller than a certain threshold value, the adjustment toner pattern having a toner amount corresponding to the difference between the image area ratio and the threshold value is obtained. By forming on the latent image carrier, a certain amount or more of toner can always be consumed. Accordingly, it is possible to reduce the deterioration of the toner and the carrier due to the low toner consumption. Further, in the present embodiment, toner scattering and abnormal images due to toner deterioration can be suppressed, and there is an advantage that carrier deterioration due to low toner balance is small.
Since the carrier deterioration state changes between when the adjustment pattern is formed and when it is not formed, the life of the developer is likely to vary, and the life of the developer is determined when a predetermined number of pages have been printed as in the past. If it is determined that the developer life is, the developer life (developer replacement time) must be set short. However, in the present invention, since the life of the developer is calculated from the image area ratio and the number of continuously printed pages per job, the conventional problem does not occur. Accordingly, it is possible to reduce waste and achieve cost reduction and environmental load reduction.
Note that the method for calculating the developer life X shown in the present embodiment may be realized by a program that causes a computer to execute the method. Further, the program can be distributed by storing it in a computer-readable storage medium such as a CD-ROM.

[Third embodiment]
A third embodiment of the present invention will be described with reference to FIGS. FIG. 11 is a diagram showing a relationship between the average image area ratio A and the developer life according to the present embodiment. FIG. 12 is a table showing developer life correction coefficients according to the present embodiment. This embodiment is characterized in that a carrier is mixed in a toner bottle. Hereinafter, the description of the same parts as those of the first and second embodiments is omitted.
In the present embodiment, in the toner bottle 59 of the printer 1 (see FIG. 1), an amount of carrier having a ratio of 10 wt% is mixed in advance.
In FIG. 11, compared to FIG. 4, the developer life on the high image area ratio side indicated by oblique lines is improved. This is because a new carrier is replenished in printing with a high image area ratio with a large amount of toner replenishment, and the deterioration state of the entire carrier is suppressed. Note that the excess developer in the developing unit 130 due to toner replenishment is automatically discharged out of the developing unit 130 by a developer discharge screw (not shown) (see FIG. 2).
The correction coefficient a in the present embodiment is derived based on FIG. Note that the calculation methods of the correction coefficient a, the correction coefficient b, the developer life reference value D, and the developer life X are the same as those in the first embodiment, and thus description thereof is omitted.
FIG. 13 shows a comparison of the number of pages printed until the developer replacement in this embodiment and the conventional example when repeated printing is performed under conditions of an average image area ratio of 5 [%] and an average duty of 5 [page / job]. It is a figure to do. In the present embodiment, the cumulative number of printed pages until the developer replacement is increased, and the developer can be used without waste.

As described above, according to this embodiment, not only the toner but also a certain amount of carrier is contained in the toner bottle, whereby a new carrier is replenished little by little in the developing unit, and the excess developer is supplied as the developer. Since it is discharged out of the developing device by the discharge device, the life of the carrier can be extended.
In the configuration of the present embodiment, since the carrier replacement rate varies depending on the image area ratio, there is a problem that the life of the developer greatly varies depending on the image area ratio. For example, when it is determined that the life of the developer is due to the printing of a predetermined number of pages as in the past, there is a problem that the developer life (developer replacement time) must be set short. . Specifically, even if the carrier life is extended by replenishing the carrier, the carrier life may not be extended in an extreme use environment where there is almost no toner balance, resulting in a shorter developer life. There is a problem that it must be set. However, in this embodiment, a new carrier is replenished in the developing unit, and the developer replacement time is determined by predicting the deteriorated state of the carrier, so that the extended carrier lifetime can be appropriately determined. And can maximize the effect of extending the carrier life.

[Fourth Embodiment]
A fourth embodiment of the present invention will be described with reference to FIG. FIG. 14 is a diagram showing a printer maintenance management system according to the present embodiment. In this embodiment, the printer 1 (1a, 1b, 1c) shown in the first to third embodiments and the service side terminal 301 for performing management including maintenance and inspection of the printer 1 are connected to the communication network. The printer is characterized in that a printer maintenance management system 300 is constructed by connecting via the network 302.
The printer 1 calculates the developer life X from the correction coefficient a derived based on the average image area ratio A, the correction coefficient b derived based on the average duty B, and the developer life reference value D, and the developer The service life X is transmitted to the service side terminal 301 as a developer replacement time prediction result. In addition, the printer 1 also transmits the cumulative print page number C to the service side terminal 301. The service-side terminal 301 manages the prediction result received from the printer 1 and the cumulative print page number C as maintenance management information.
As is apparent from the descriptions in the first to third embodiments, the correction coefficients a and b vary depending on the printing conditions of the printer 1, so that the developer life X also varies as the cumulative print page number C increases. Therefore, it is desirable that the printer 1 transmits the developer life X to the service side terminal 301 at a predetermined interval, for example, every predetermined cumulative number of printed pages or every predetermined period. Further, the service-side terminal 301 can more accurately predict the developer replacement time by managing the received cumulative number of printed pages C, the developer life X, and the fluctuation status of the developer life X as maintenance management information. Can do.

  As described above, according to the present embodiment, since the service side terminal manages the developer replacement time predicted based on the maintenance management information, the developer replacement is performed based on the predicted developer replacement time information. Service can be provided. Therefore, the developer can be replaced more smoothly and accurately, and the downtime of the printer can be reduced.

  DESCRIPTION OF SYMBOLS 1, 1a, 1b, 1c ... Printer, 200, 210 ... Control means, 201 ... Counting means, 202 ... Image area ratio calculation means, 203 ... Average image area ratio calculation means, 204 ... Average duty calculation means, 205 ... Storage means 207, correction coefficient deriving means, 207 developer life calculating means, 211 image area ratio difference determining means, 300 maintenance management system, 301 service-side terminal, 302 communication network

JP 2008-076428 A JP 2004-233826 A JP 2009-015046 A

Claims (7)

An image forming apparatus for developing a latent image on a latent image carrier with a two-component developer composed of a toner and a carrier,
Counting means for counting the cumulative number of printed pages and the number of continuous printed pages per job;
Image area ratio calculating means for calculating an image area ratio per page printed on the recording medium;
An average image area rate calculating unit that calculates an average image area rate per page based on the cumulative number of printed pages counted by the counting unit and the image area rate calculated by the image area rate calculating unit;
An average duty calculating means for calculating an average number of continuous printed pages per job based on the number of continuous printed pages per job counted by the counting means;
Correction coefficient deriving means for deriving a correction coefficient for the developer life reference value from the average image area ratio and the average number of continuously printed pages;
An image forming apparatus comprising: developer life calculating means for calculating the developer life by multiplying the developer life reference value by the correction coefficient . When the image area ratio is equal to or less than a predetermined threshold value, the image area ratio difference determining means for calculating a toner amount corresponding to the difference between the threshold value and the image area ratio is provided. the image forming apparatus according to claim 1, wherein the adjusting toner pattern for consuming toner calculated amount be formed on the latent image bearing member judging means. The image forming apparatus according to claim 2 , wherein the toner pattern for adjustment is formed outside a transfer region. And an image forming apparatus of any one of claims 1 to 3, a service terminal that manages the maintenance and inspection information of the image forming apparatus, and a communication network for connecting the service terminal and the image forming apparatus, a Prepared,
The image forming apparatus transmits the developer life calculated by the developer life calculating means to the service terminal. A developer life calculation method in an image forming apparatus that develops a latent image on a latent image carrier with a two-component developer comprising a toner and a carrier,
A counting means for counting the cumulative number of printed pages and the number of continuous printed pages per job;
An image area ratio calculating unit calculating an image area ratio per page printed on the recording medium;
An average image area rate calculating unit calculating an average image area rate per page based on the cumulative number of printed pages counted by the counting unit and the image area rate calculated by the image area rate calculating unit;
An average duty calculating unit calculating an average continuous printed page number per job based on the continuous printed page number per job counted by the counting unit;
A correction coefficient deriving unit deriving a correction coefficient for the developer life reference value from the average image area ratio and the average continuous print page number;
A developer life calculating method, comprising: calculating a developer life by multiplying the developer life reference value by the correction coefficient . A developer life calculation program for causing a computer to execute the developer life calculation method according to claim 5 . A computer-readable storage medium having the developer life calculation program according to claim 6 recorded thereon.

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