Image forming device and determination method

Abstract

An image forming device and a judgment method. The image forming device of an embodiment includes: a developer, a developer container, and a control unit. The developer contains a developer containing a colorant and a carrier, and has a stirrer for stirring the developer. The developer container contains the developer supplied to the developer. The control unit obtains a degradation index indicating the degree of deterioration of the developer in the developer based on stirring accumulation information and supply accumulation information, and judges the timing of replacing the developer based on historical information of the degradation index. The stirring accumulation information is information related to the cumulative value of the time the stirrer stirs the developer in the developer, and the supply accumulation information is information related to the cumulative amount of the developer supplied from the developer container to the developer.

Description

Technical Field

[0001] The present embodiment generally relates to an image forming apparatus and a determination method. Background Art

[0002] Conventionally, the following technology is known: new developer is supplied to the developer, and old developer is discharged from the developer, thereby maintaining the performance of the developer in the developer. In addition, the following technology is known: a small amount of carrier (such as a magnetic body) is pre-mixed in a cylinder containing the toner supplied to the developer, and the carrier is also supplied together with the toner. In such a technology, the carrier in the developer is supplied and discharged at the same time as the toner is supplied to the developer. Therefore, if the supply of toner is small, it is difficult to replace the carrier in the developer. That is, if the print rate of the output image is low, it is not easy to replenish the carrier, and the carrier in the developer cannot be fully replaced. In the case where the replacement of the carrier in the developer is insufficient, there is a problem that the deterioration of the developer is aggravated, resulting in poor image quality. Summary of the Invention

[0003] The image forming device in the embodiment comprises: a developer that accommodates a developer containing a colorant and a carrier and has a stirrer that stirs the developer; a developer container that accommodates the developer supplied to the developer; and a control unit that obtains a degradation index indicating the degree of deterioration of the developer in the developer based on stirring accumulation information and supply accumulation information, and determines the timing of replacing the developer based on historical information of the degradation index, the stirring accumulation information being information related to the cumulative value of the time the stirrer stirs the developer in the developer, and the supply accumulation information being information related to the cumulative amount of the developer supplied from the developer container to the developer. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] Figure 1 1 is an external view showing an example of the overall configuration of the image forming apparatus 100 according to the embodiment.

[0005] Figure 2 1 is a diagram showing a configuration example of a portion of the image forming unit 130 .

[0006] Figure 3 It is a perspective view showing an example of the appearance of the developing unit 35 .

[0007] Figure 4 This is a hardware block diagram of the image forming apparatus 100 according to the embodiment.

[0008] Figure 5 It is a diagram showing a specific example of the history of degradation indices.

[0009] Figure 6: is a graph showing an example of changes in the degradation index in usage pattern d.

[0010] Figure 7 This is a flowchart showing a specific example of the operation of image forming apparatus 100 .

[0011] Figure 8 This is a hardware block diagram of image forming apparatus 100 according to a modification of the embodiment. DETAILED DESCRIPTION

[0012] Figure 1 This is an external view showing an example of the overall structure of an image forming apparatus 100 according to an embodiment. The image forming apparatus 100 is, for example, a multifunction peripheral. The image forming apparatus 100 includes a display 110, a control panel 120, an image forming unit 130, a sheet storage unit 140, and an image reading unit 200. A developer cartridge is installed in the image forming apparatus 100. The developer cartridge can be filled with either a decolorizable toner that can be subsequently removed or a non-decolorizable toner.

[0013] The image forming apparatus 100 forms an image on a sheet using toner. The sheet is, for example, paper or label paper. The sheet can be any object as long as the image forming apparatus 100 can form an image on its surface.

[0014] The display 110 is an image display device such as a liquid crystal display, an organic EL (Electro Luminescence) display, etc. The display 110 displays various information related to the image forming apparatus 100 .

[0015] The control panel 120 includes a plurality of buttons. The control panel 120 receives user operations and outputs signals corresponding to the user operations to the control unit 160 of the image forming apparatus 100. The display 110 and the control panel 120 may be formed as an integrated touch panel.

[0016] The image forming unit 130 forms an image on a sheet based on the image information generated by the image reading unit 200 or the image information received via the communication path. The image forming unit 130 forms an image by, for example, the following processing. The image forming unit 130 forms an electrostatic latent image on a photosensitive drum based on the image information. The image forming unit 130 forms a visible image by attaching a colorant to the electrostatic latent image. Specific examples of the colorant include decolorizing toner, non-decolorizing toner (normal toner), decorative toner, and the like. There are also toners whose color fades (disappears) when heated.

[0017] Image forming unit 130 transfers the visible image onto a sheet. Image forming unit 130 heats and pressurizes the sheet to fix the visible image onto the sheet. It should be noted that the sheet on which the image is formed can be a sheet contained in sheet storage unit 140 or a sheet manually inserted.

[0018] The image reader 200 reads image information of the object as light and dark. The image reader 200 records the read image information. The recorded image information can be transmitted to other information processing devices via a network. The recorded image information can also be formed into an image on a sheet by the image forming unit 130.

[0019] Figure 2 1 is a diagram showing a partial configuration example of the image forming unit 130 , which includes a cartridge 2 (developer cartridge), a sensor 17 , a developer supply motor 31 (feeder), a cleaning unit 32 , a charger 33 , a photoreceptor 34 , and a developing device 35 .

[0020] The sensor 17 outputs a physical quantity (a first physical quantity) that is correlated with the amount of toner remaining in the developer 35 of the image forming apparatus 100. In the following description, the greater the amount of toner remaining in the developer 35, the larger the value of the first physical quantity. The sensor 17 may be configured using, for example, an automatic toner sensor. In this case, the sensor 17 may also be configured to detect the concentration of the toner. Alternatively, the sensor 17 may be configured to detect the remaining amount of toner. The sensor 17 may also be configured using, for example, a sensor that measures magnetic permeability.

[0021] The cartridge 2 is configured to be attachable to and detachable from the image forming apparatus 100. The cartridge 2 is filled with a developer containing toner and a carrier. The developer supply motor 31 operates to supply the developer in the cartridge 2 to the developing device 35. The cleaning unit 32 removes toner adhering to the surface of the photoreceptor 34. The charger 33 charges the surface of the photoreceptor 34. The photoreceptor 34 has a surface on which an image is formed using toner.

[0022] Figure 3This is a perspective view showing an example of the appearance of the developer 35. The developer 35 is configured to accommodate developer. The developer 35 includes a developing roller 41, a developer supply port 42, and a developer discharge port 43. The developer 35 supplies toner to the photoreceptor 34 via the developing roller 41. A predetermined amount of carrier exists in the developer 35. By stirring the toner and the carrier, electric charge is generated in the toner. The amount of carrier present in the developer 35 is approximately constant. Therefore, when the amount of toner in the developer 35 is large, the amount of carrier becomes relatively small. On the other hand, when the amount of toner in the developer 35 is small, the amount of carrier becomes relatively large. In this way, physical quantities such as magnetic permeability change according to the amount of toner in the developer 35. The sensor 17 detects the amount of toner in the developer 35 based on the physical quantity that changes in this way.

[0023] When the developer supply motor 31 is driven, the developer in the box 2 moves to the developer 35 via the developer supply port 42. The colorant contained in the developer moved to the developer 35 adheres to the electrostatic latent image of the photoreceptor 34 during image formation. A visible image is formed by the adhesion of the colorant. If the colorant in the developer 35 is used for image formation, the amount of the colorant in the developer 35 gradually decreases. The amount of the colorant in the developer 35 is detected based on the output of the sensor 17. When it is determined that the amount of the colorant in the developer 35 is less than the lower limit threshold, the developer supply motor 31 is driven until the amount of the colorant reaches or exceeds the upper limit threshold. By driving the developer supply motor 31, the developer in the box 2 moves to the developer 35.

[0024] As the developer moves into the developing unit 35, it overflows. The overflowed developer is discharged outside the developing unit 35 through the developer discharge port 43. This overflow of developer maintains a constant amount of developer within the developing unit 35, and degraded carrier within the developing unit 35 is discharged to the outside. As new carrier is supplied to the developing unit 35 as developer, the carrier within the developing unit 35 is gradually replaced with new carrier. This replacement of the developer within the developing unit 35 is performed for each developing unit 35 corresponding to each toner.

[0025] Figure 4 This is a hardware block diagram of the image forming apparatus 100 according to the embodiment. The image forming apparatus 100 includes an image reading unit 200, a display 110, a control panel 120, an image forming unit 130, a sheet storage unit 140, a storage unit 150, a control unit 160, and a communication unit 170. The image reading unit 200, display 110, control panel 120, image forming unit 130, and sheet storage unit 140 have already been described, and therefore their description is omitted.

[0026] The storage unit 150 is constructed using a storage device such as a magnetic hard disk drive or a semiconductor memory device. The storage unit 150 stores data required for the operation of the image forming apparatus 100. For example, the storage unit 150 may store data for a program executed by the control unit 160. For example, the storage unit 150 may temporarily store image data generated by the image forming apparatus 100. For example, the storage unit 150 may store image data generated by the image reading unit 200. For example, the storage unit 150 may store information indicating conditions for determination by the control unit 160 or the value of a counter.

[0027] The control unit 160 is configured using a processor such as a CPU (Central Processing Unit) and memory. The control unit 160 reads and executes programs pre-stored in the storage unit 150. The control unit 160 controls the operation of each device included in the image forming apparatus 100. The control unit 160 controls the driving of the developer supply motor 31 based on the physical quantity output from the sensor 17. For example, if the physical quantity output from the sensor 17 indicates a decrease in toner concentration, the control unit 160 drives the developer supply motor 31 to supply developer to the developing unit 35. The control unit 160 estimates the deterioration of the developer within the developing unit 35.

[0028] The communication unit 170 is a communication interface for performing data communication with other devices according to a predetermined communication protocol.

[0029] Next, the processing of the control unit 160 is described in more detail. The control unit 160 obtains information related to the cumulative value of the time for stirring the developer in the developer 35 in the image forming apparatus 100 (hereinafter referred to as "stirring accumulation information"). The control unit 160 obtains information related to the cumulative amount of developer supplied to the developer 35 (hereinafter referred to as "supply accumulation information"). The control unit 160 obtains the stirring accumulation information and the supply accumulation information for each developer 35. For example, when the developer 35 is set for each color of Y (yellow), M (magenta), C (cyan), and K (black), the control unit 160 obtains the stirring accumulation information and the supply accumulation information for each color. Based on the stirring accumulation information and the supply accumulation information, the control unit 160 estimates the degree of deterioration of the developer in the developer 35 for each developer 35. For example, the control unit 160 can estimate the degree of deterioration by obtaining an index value (hereinafter referred to as "deterioration index") indicating the degree of deterioration of the developer in the developer 35.

[0030] As a specific example of the accumulated agitation information, the control unit 160 can obtain the accumulated value of the number of sheets printed in the image forming apparatus 100 (hereinafter referred to as the "printed sheet count value"). As a specific example of the accumulated agitation information, the control unit 160 can obtain the accumulated value of the driving time of the developer 35 (hereinafter referred to as the "developer count value"). The developer count value can be obtained by, for example, counting every two seconds while the developer 35 is being driven.

[0031] As a specific example of replenishment accumulation information, the control unit 160 can obtain the cumulative value of the driving time of the developer replenishment motor 31 (hereinafter referred to as the "replenishment motor count value"). The replenishment motor count value can be obtained, for example, by counting every 12 seconds while the developer replenishment motor 31 is driven. As a specific example of replenishment accumulation information, the control unit 160 can obtain the cumulative value of the value obtained by multiplying the printing rate by the number of printed sheets. As a specific example of replenishment accumulation information, the control unit 160 can obtain the cumulative value of the number of printed pixels.

[0032] Next, a specific example will be described of a process in which the control unit 160 uses the developer count value as the agitation accumulation information and the replenishment motor count value as the replenishment accumulation information.

[0033] The control unit 160 records the developer count value and the supply motor count value in the storage unit 150. The control unit 160 updates these count values at a predetermined update timing. The update timing may be, for example, the timing after a printing job is executed. The control unit 160 updates these count values to zero by initializing them at a predetermined initialization timing (initialization processing). The initialization timing may be, for example, the timing when the developer is first added to the developer 35, the timing when the developer is replaced, or the timing when an initial action (such as a toner concentration adjustment action) is performed after the developer is replaced. The initialization timing may also be automatically determined as the timing when the developer replacement is detected by a sensor or the like provided in the developer 35. The initialization timing may also be manually indicated by a person who replaces the developer in the developer 35.

[0034] The control unit 160 can calculate the degradation index based on the following equation, for example.

[0035] Current degradation index = (last degradation index + A) × (1-B) × 100

[0036] A = (current developer count value - previous developer count value) / developer count reference value

[0037] B = (current supply motor count value - last supply motor count value) / supply motor count reference value

[0038] In the above formula, the developer count reference value represents the driving time counter value of the developer 35 required for printing during the period without replenishing the carrier until the developer performance reaches the replacement level. In addition, the supply motor count reference value represents the supply time counter value of the box 2 required to replenish the developer 35 with the amount of developer that fills the capacity of the developer 35. In addition, the current degradation index is the latest degradation index newly calculated, and the last degradation index is the degradation index calculated in the previous process. The current developer count value is the latest developer count value, and the last developer count value is the developer count value obtained in the previous process. The current supply motor count value is the latest supply motor count value, and the last supply motor count value is the supply motor count value obtained in the previous process.

[0039] The value of A calculated in this manner represents the rate at which the developer deteriorated between the end of the previous print job and the end of the current print job. The value of B calculated in this manner represents the rate at which the developer was replaced (refreshed) with fresh developer between the end of the previous print job and the end of the current print job. It should be noted that the driving of the developer 35 in this embodiment is not so-called continuous printing, but rather an operating mode (so-called intermittent operation) in which the developer prints a predetermined number of sheets (e.g., five sheets) in succession, then stops and resumes printing.

[0040] The term "previous degradation index + A" in the first half of the right-hand side of the equation for calculating the current degradation index represents the rate at which the developer deteriorated due to agitation in the developer 35 during the current print job. The term "1 - B" in the second half of the right-hand side represents the rate at which new developer was supplied to the developer 35 during the current print job but remained unreplaced (unupdated) and thus within the developer 35. By multiplying the terms in the first and second half, the degradation state of the developer contained within the developer 35 can be estimated.

[0041] The control unit 160 can determine the necessity of replacing the developer based on the history of the degradation index. A specific example of the determination process will be described. Figure 5 This graph shows a specific example of the degradation index history. The horizontal axis represents the number of printed sheets. The vertical axis represents the degradation index, with "100" representing the threshold. When the degradation index exceeds the threshold, it indicates that the developer in the developing unit 35 is deteriorating and is likely to require replacement.

[0042] For example, in usage mode a, in which a large amount of printing is performed at an average printing rate of more than 10%, the carrier is frequently replaced. Therefore, the degradation index maintains a low value and the degradation index does not exceed the threshold value. On the other hand, in usage mode a, in which printing is almost performed at an average printing rate of about 1%, the carrier is not easily replaced, so the degradation index gradually increases, and the degradation index exceeds the threshold value when about 150K sheets are printed. In usage mode c, although the average printing rate is more than 10% until about 300K sheets, the average printing rate drops to about 1% thereafter. Therefore, after printing about 300K sheets, the degradation index gradually increases, and the degradation index exceeds the threshold value when about 400K sheets are printed.

[0043] The control unit 160 may estimate the following matters based on the history of the degradation index up to that point in each usage mode, and may output the estimation result.

[0044] At the current moment, whether the deterioration has progressed to the point where the developer needs to be replaced (whether replacement is required)

[0045] Timing when deterioration progresses to the point where the developer's effect becomes necessary (replacement timing)

[0046] The control unit 160 can calculate the degradation process index when judging whether replacement is necessary, and make a judgment based on the degradation index and the degradation process index. The degradation process index is an index that represents the time-dependent change in the degradation of the developer. The degradation process index can be, for example, a statistical value (such as a maximum value) that represents the magnitude of the change in the degradation index during a specified period from the present to the past (such as a differential value), or it can be another value. When the degradation index exceeds a threshold value and the degradation process index is a value indicating that there is no specified sharp change during the above-mentioned specified period (for example, from the present to the past 1 week, etc.), the control unit 160 judges that the developer needs to be replaced. These two conditions are collectively referred to as degradation conditions. On the other hand, even if the degradation index exceeds the threshold value, when the degradation process index is a value indicating that there is a specified sharp change during the specified period, the control unit 160 judges that the developer does not need to be replaced.

[0047] Regarding the reasons for this judgment, Figure 6 Provide explanation. Figure 6: This is a diagram showing an example of the change of the degradation index in usage mode d. In usage mode d, printing is performed at an average printing rate of 10% or more in most of the printing, but printing is performed at an extremely low average printing rate (for example, about 0.5%) in a certain short period. Therefore, in a specific short period, the value of the degradation index sometimes deteriorates sharply and exceeds the threshold. However, if the specific short period ends, printing starts again at a higher average printing rate. Therefore, if the specific short period ends, the degradation index will improve sharply. Therefore, even if the degradation index temporarily exceeds the threshold, the degradation index will naturally improve without the need to replace the developer. In such usage mode d, the degradation process index indicates a specified sharp change in a specified period. Therefore, when the degradation process index is such a value, it is determined that the developer does not need to be replaced.

[0048] The output destination of the estimation result can be the display 110 of the image forming apparatus 100, the information processing device (e.g., a personal computer, a smartphone) of the user of the image forming apparatus 100, or the information processing device (e.g., a personal computer, a smartphone) of the maintenance personnel of the image forming apparatus 100. When the estimation result is output to another device, the information is transmitted via the communication unit 170. By referring to such estimation results, maintenance personnel can, for example, replace the developer at an appropriate time. In addition, for usage patterns such as usage pattern c where the average printing rate changes midway, maintenance personnel can also replace the developer at an appropriate time.

[0049] Figure 7 1 is a flowchart showing a specific example of the operation of the image forming apparatus 100. First, the control unit 160 performs initialization processing (ACT101). Next, the control unit 160 transitions to a state of waiting for a print job (ACT102). Then, when a print job is input, the control unit 160 starts the print job (ACT103). When the print job ends (ACT104), the control unit 160 obtains each count value at that moment and calculates a degradation index (ACT105). In addition, the control unit 160 calculates a degradation process index based on the history of the degradation index up to that moment (ACT106). The control unit 160 determines whether the degradation condition is met based on the calculated degradation index and the degradation process index (ACT107). If the degradation condition is not met (ACT107-No), the control unit 160 returns to the processing of ACT102. On the other hand, if the degradation condition is met (ACT107-Yes), the control unit 160 outputs that the degradation condition is met (ACT108).

[0050] According to the image forming apparatus 100 configured in this manner, the timing at which the developer in the developing unit 35 should be replaced due to degradation is determined based on the degradation history. Figure 5 Even in the case of various usage patterns, it is possible to make a high-precision judgment. Figure 6 Even if the degradation index deteriorates extremely temporarily and exceeds the threshold, but it is expected to improve later based on the history so far, it is not determined as the timing for replacement. Therefore, unnecessary replacement of the developer can be suppressed.

[0051] It should be noted that the control unit 160 can also Figure 5 The history of the degradation index is displayed on the display 110. In this case, only one actual graph among the graphs represented by the three types of lines may be displayed.

[0052] Figure 8 This is a hardware block diagram of the image forming apparatus 100a involved in a modified example of the embodiment. In the modified example, the image forming apparatus 100a includes a control unit 160a and a communication unit 170a instead of the control unit 160 and the communication unit 170. The control unit 160a communicates with the information device 300 via the communication unit 170a. The control unit 160a can, for example, send each count value to the information device 300 via the communication unit 170a. In this case, the information device 300 can calculate the degradation index, record the history of the degradation index, and calculate the degradation process index instead of the control unit 160a. In this case, the information device 300 can prompt the user or maintenance personnel of the image forming apparatus 100a with the degradation index, the history of the degradation index, the degradation process index, the judgment result, etc.

[0053] Although several embodiments have been described, these embodiments are provided for illustrative purposes only and are not intended to limit the scope of the invention. These embodiments can be implemented in various other ways and can be omitted, replaced, or modified without departing from the spirit of the invention. These embodiments and their variations are intended to be included within the scope and spirit of the invention and are also intended to be included within the scope of the invention set forth in the claims and their equivalents.

Claims

1. An image forming apparatus comprising: a developer containing a developer including a toner and a carrier and having a stirrer for stirring the developer; a developer container for storing developer supplied to the developer; and a control unit that acquires a degradation index indicating a degree of degradation of the developer in the developer based on cumulative stirring information and cumulative replenishment information, and determines a timing for replacing the developer based on historical information of the degradation index, wherein the cumulative stirring information is information related to a cumulative value of a time during which the developer in the developer is stirred by the stirrer, and the cumulative replenishment information is information related to a cumulative amount of the developer supplied from the developer container to the developer. The control unit determines that it is time to replace the developer when the degradation index exceeds a predetermined threshold value indicating that the developer has deteriorated and a degradation progress index indicating a magnitude of change in the degradation index in the history of the degradation index indicates that the degradation index has not changed rapidly.

2. The image forming apparatus according to claim 1, wherein The image forming apparatus includes a plurality of developers. The control section determines the timing at which the developer should be replaced for each developing device.

3. The image forming apparatus according to claim 1, wherein The control unit acquires a cumulative value of the driving time of the developing device as the agitation cumulative information.

4. The image forming apparatus according to claim 1, wherein The control unit acquires a cumulative value of the number of sheets printed in the image forming apparatus as the cumulative agitation information.

5. The image forming apparatus according to claim 1, wherein The image forming apparatus further includes a supply motor configured to supply the developer from the developer container to the developing device by driving the supply motor. The control unit acquires a cumulative value of a driving time of the replenishment motor as the replenishment accumulation information.

6. The image forming apparatus according to claim 1, wherein The control unit calculates the degradation index using a value obtained by dividing a difference between the current accumulated agitation information and the accumulated agitation information at a predetermined time in the past by accumulated agitation information required for printing until the developer performance deteriorates to a state requiring replacement without replenishing the carrier.

7. The image forming apparatus according to claim 1, wherein The control unit calculates the degradation index using a value obtained by dividing a difference between the current supply accumulation information and the supply accumulation information at a predetermined timing in the past by the supply accumulation information required to replenish the developer in an amount sufficient to fill the developer capacity.

8. A judgment method, wherein: An image forming apparatus includes: a developing unit that contains a developer containing a toner and a carrier and has a stirrer for stirring the developer; and a developer container that contains the developer supplied to the developing unit. The image forming apparatus operates as follows: acquiring agitation accumulation information, the agitation accumulation information being information related to a cumulative value of a time for which the agitator agitates the developer in the developer; acquiring supply accumulation information indicating information related to a cumulative amount of developer supplied from the developer container to the developer; acquiring a degradation index indicating a degree of degradation of the developer in the developer based on the agitation accumulation information and the replenishment accumulation information, determining the timing of replacing the developer based on the historical information of the degradation index; When the degradation index exceeds a predetermined threshold value and indicates that the developer has deteriorated, and a degradation progress index indicating a change in the degradation index in the degradation index history indicates that the degradation index has not changed rapidly, it is determined that the developer should be replaced.

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