Image forming apparatus

Abstract

To provide a technique that can determine the amount of consumption of a transfer unit, considering deterioration of a belt along with supply of current.SOLUTION: An image forming apparatus 1 comprises: a cleaning roller 61 that cleans a belt 52 of a transfer unit 5, and a current supply circuit 7 that supplies current to the cleaning roller 61. A control section 8 of the image forming apparatus 1 calculates the amount of consumption of the transfer unit on the basis of a cumulative value of the values of current supplied from the current supply circuit 7 to the cleaning roller 61. The amount of consumption of the transfer unit 5 can thus be determined, considering deterioration of the belt 52 along with the supply of current to the cleaning roller 61.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an image forming apparatus. [Background technology]

[0002] Conventionally, electrophotographic image forming apparatuses such as laser printers and LED printers are known. The image forming apparatus has a photosensitive drum and a transfer unit. When printing is performed in the image forming apparatus 1, printing paper is fed between the photosensitive drum and the transfer unit. Then, toner is transferred from the photosensitive drum to the printing paper between the photosensitive drum and the transfer unit.

[0003] Conventional image forming apparatuses having a transfer unit are described in, for example, Patent Documents 1 and 2. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-52329 [Patent Document 2] Japanese Patent Publication No. 2022-25449 Summary of the Invention [Problem to be solved by the invention]

[0005] The transfer unit has a transfer roller and a belt. The image forming device supplies current to the transfer roller, which then applies a voltage corresponding to the current to the transfer roller. The printing paper is transported by the belt between the photosensitive drum and the transfer roller. At this time, the toner is transferred from the photosensitive drum to the printing paper by electrostatic force generated by the voltage on the transfer roller.

[0006] The image forming apparatus also has a cleaning roller that collects toner from the belt. The image forming apparatus supplies a current to the cleaning roller. This applies a voltage corresponding to the current to the cleaning roller. The electrostatic force generated by this voltage then causes the toner to be collected from the belt onto the cleaning roller.

[0007] However, when the transfer unit is used for a long period of time, the belt may deteriorate due to the supply of current to the transfer roller and cleaning roller.

[0008] An object of the present disclosure is to provide a technique that can determine the wear level of a transfer unit, taking into account the deterioration of the belt due to the supply of current. [Means for solving the problem]

[0009] The first disclosure of the present application is characterized in that it comprises a photosensitive drum, a replaceable transfer unit having a transfer roller and a belt, a cleaning roller for cleaning the belt, a current supply circuit for supplying current to the cleaning roller, and a control unit electrically connected to the current supply circuit, and the control unit calculates the amount of wear of the transfer unit based on the cumulative value of the current value supplied from the current supply circuit to the cleaning roller.

[0010] A second disclosure of the present application is the image forming apparatus of the first disclosure, characterized in that the current supply circuit also supplies current to the transfer roller, and the control unit calculates the amount of wear of the transfer unit based on the cumulative value of the current value supplied from the current supply circuit to the transfer roller and the cumulative value of the current value supplied from the current supply circuit to the cleaning roller.

[0011] A third disclosure of the present application is the image forming apparatus of the second disclosure, characterized in that the control unit executes a belt cumulative value calculation process, which is a process that is performed periodically, to calculate a belt parameter that is the sum of the current value supplied from the current supply circuit to the cleaning roller and the current value supplied from the current supply circuit to the transfer roller, and to calculate a belt cumulative value that is the cumulative value of the belt parameter, and a first life calculation process that calculates a first life that indicates the remaining life of the transfer unit based on the belt cumulative value.

[0012] A fourth disclosure of the present application is the image forming apparatus of the third disclosure, characterized in that the control unit further executes a transfer cumulative value calculation process, which is a process that is performed periodically, to calculate transfer parameters based on the current value supplied from the current supply circuit to the transfer roller and calculate a transfer cumulative value, which is the cumulative value of the transfer parameters, and a second life calculation process that calculates a second life indicating the remaining life of the transfer unit based on the transfer cumulative value.

[0013] The fifth disclosure of the present application is the image forming apparatus of the fourth disclosure, characterized in that the control unit further executes a third life calculation process that calculates a third life indicating the remaining life of the transfer unit based on the cumulative number of rotations of the belt, a fourth life calculation process that calculates a fourth life indicating the remaining life of the transfer unit based on the cumulative number of prints by the transfer unit, and a life determination process that sets the smallest minimum life among the first life, the second life, the third life, and the fourth life as the remaining life of the transfer unit.

[0014] A sixth disclosure of the present application is the image forming apparatus of the fifth disclosure, further comprising a display, and characterized in that the control unit further executes a display step of displaying a warning on the display when the minimum life is less than a threshold value.

[0015] The seventh disclosure of the present application is an image forming apparatus according to the fifth or sixth disclosure, characterized in that the control unit reduces the current value supplied from the current supply circuit to the transfer roller when the minimum life is less than a threshold value.

[0016] An eighth disclosure of the present application is the image forming apparatus of any one of the fourth to seventh disclosures, wherein the transfer unit further has a transfer memory that stores the belt cumulative value and the transfer cumulative value.

[0017] A ninth disclosure of the present application is an image forming apparatus according to any one of the fourth to eighth disclosures, characterized in that the transfer unit has a plurality of the transfer rollers, and the control unit calculates the transfer cumulative value for each of the transfer rollers. [Effects of the Invention]

[0018] According to the first to ninth disclosures of the present application, the amount of wear of the transfer unit can be determined by taking into consideration the deterioration of the belt caused by the supply of current to the cleaning roller.

[0019] Furthermore, according to the second disclosure of the present application, the amount of wear of the transfer unit can be determined by taking into consideration the deterioration of the belt that accompanies the supply of current to the transfer roller.

[0020] Furthermore, according to the seventh disclosure of the present application, it is possible to prevent the voltage value of the transfer roller from becoming excessively high.

[0021] According to the eighth disclosure of the present application, the belt cumulative value and the transfer cumulative value are stored in the transfer memory of the transfer unit. This allows the other image forming device to appropriately determine the remaining life of the transfer unit even if the transfer unit that has been used is attached to another image forming device. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a schematic diagram of an image forming apparatus. [Figure 2]FIG. 2 is a block diagram showing electrical connections between a transfer unit, a cleaning unit, a current supply circuit, and a control unit. [Figure 3] 10 is a flowchart showing the flow of an initial process. [Figure 4] 10 is a flowchart showing the flow of a latch process. [Figure 5] 10 is a diagram showing an example of a table showing the relationship between contract information, transfer unit types, and transfer unit usage modes. FIG. [Figure 6] 10 is a flowchart showing the flow of a periodic execution process. [Figure 7] 10 is a flowchart showing the flow of a print sheet count process. [Figure 8] 10 is a flowchart showing the flow of a belt rotation count process. [Figure 9] 10 is a flowchart showing the flow of a transfer cumulative value calculation process. [Figure 10] 10 is a flowchart showing the flow of a belt cumulative value calculation process. [Figure 11] 10 is a flowchart showing the flow of a lifespan determination process. [Figure 12] 10 is a flowchart showing the flow of a lifespan determination process. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, preferred embodiments of the present disclosure will be described with reference to the drawings.

[0024] <1. Configuration of image forming device> FIG. 1 is a schematic diagram of an image forming apparatus 1. This image forming apparatus 1 is an electrophotographic printer. Specifically, the image forming apparatus 1 is a laser printer or an LED printer. The image forming apparatus 1 includes a main body frame 2, four developing cartridges 3, a drum unit 4, a transfer unit 5, a cleaning unit 6, a current supply circuit 7, a control unit 8, and a display 9.

[0025] The main body frame 2 has an insertion slot 21 and a cover 22. The cover 22 is rotatable between an open position where the insertion slot 21 is open and a closed position where the insertion slot 21 is closed. The image forming apparatus 1 has a cover sensor 23 that detects that the cover 22 has been rotated from the open position to the closed position. When the cover sensor 23 detects that the cover 22 has been rotated from the open position to the closed position, it transmits a detection signal to the control unit 8.

[0026] The four developer cartridges 3 can be individually attached to and detached from the drum unit 4. Furthermore, the drum unit 4 with the four developer cartridges 3 attached can be attached to and detached from the main body frame 2. The drum unit 4 with the four developer cartridges 3 attached is attached to the main body frame 2 via an insertion port 21.

[0027] Each of the four developer cartridges 3 has a developer roller 31. The drum unit 4 has four photosensitive drums 41. When a developer cartridge 3 is attached to the drum unit 4, the developer roller 31 comes into contact with the photosensitive drum 41. The four developer cartridges 3 contain toner of different colors (for example, cyan, magenta, yellow, and black).

[0028] The transfer unit 5 is a unit for transferring toner from the photosensitive drum 41 to a printing paper. The transfer unit 5 is detachable from the main body frame 2. In other words, the transfer unit 5 is a replaceable unit.

[0029] The transfer unit 5 has a first pulley 51a, a second pulley 51b, a belt 52, and four transfer rollers 53. The belt 52 is a circular flat belt. The belt 52 is stretched between the first pulley 51a and the second pulley 51b. The first pulley 51a rotates by power output from a motor (not shown). This causes the belt 52 to rotate between the first pulley 51a and the second pulley 51b. The second pulley 51b rotates in accordance with the rotation of the belt 52.

[0030] The transfer roller 53 is a roller for transferring toner from the photosensitive drum 41 to the printing paper. When the transfer unit 5 is attached to the main body frame 2 and the drum unit 4, to which the four developer cartridges 3 are attached, is also attached to the main body frame 2, a part of the belt 52 is positioned between the photosensitive drum 41 and the transfer roller 53. Specifically, a part of the belt 52 is sandwiched between the photosensitive drum 41 and the transfer roller 53.

[0031] The cleaning unit 6 is a unit for cleaning the belt 52. The cleaning unit 6 is detachable from the main body frame 2. In other words, the cleaning unit 6 is a replaceable unit.

[0032] The cleaning unit 6 has a cleaning roller 61 and a waste toner box 62. The cleaning roller 61 is a roller that cleans the belt 52. The cleaning roller 61 comes into contact with the outer surface of the belt 52. The cleaning roller 61 collects toner from the outer surface of the belt 52. The toner collected by the cleaning roller 61 is stored in the waste toner box 62.

[0033] The current supply circuit 7 is an electric circuit for supplying current to the transfer rollers 53 and the cleaning rollers 61. The current supply circuit 7 is located inside the main body frame 2. FIG. 2 is a block diagram showing the electrical connections between the transfer unit 5, the cleaning unit 6, the current supply circuit 7, and the control unit 8. As shown in FIG. 2, the current supply circuit 7 is electrically connected to the control unit 8. Furthermore, when the cleaning unit 6 and the transfer unit 5 are attached to the main body frame 2, the current supply circuit 7 is electrically connected to the four transfer rollers 53 and the cleaning rollers 61.

[0034] The control unit 8 is located within the main body frame 2. As shown in FIG. 2, the control unit 8 has a processor 81 such as a CPU, and a main body memory 82. The main body memory 82 is a storage medium from which information can be read and written. The processor 81 can read information from the main body memory 82 and write information to the main body memory 82. The control unit 8 executes printing processing in the image forming apparatus 1 by the processor 81 operating in accordance with a program stored in the main body memory 82.

[0035] The display 9 is, for example, a liquid crystal display or an organic EL display. The display 9 is electrically connected to the control unit 8. In accordance with instructions from the control unit 8, the display 9 displays various information related to the operation of the image forming apparatus 1 on the screen.

[0036] When the image forming apparatus 1 performs a printing process, the toner contained in the developer cartridge 3 is supplied to the photosensitive drum 41 via the developer roller 31. The toner moves from the developer roller 31 to the photosensitive drum 41 in accordance with the electrostatic latent image formed on the outer circumferential surface of the photosensitive drum 41. The printing paper is also transported between the belt 52 and the four photosensitive drums 41. At this time, a current is supplied from the current supply circuit 7 to the transfer roller 53. A voltage corresponding to the current is then applied to the transfer roller 53. The toner carried on the outer circumferential surface of the photosensitive drum 41 is transferred from the outer circumferential surface of the photosensitive drum 41 to the printing paper by electrostatic force due to the voltage of the transfer roller 53. As a result, a toner print image is formed on the surface of the printing paper.

[0037] <2. About the Subscription Agreement> A user of the image forming device 1 can enter into a subscription contract for the transfer unit 5 with the manufacturer of the transfer unit 5. If a subscription contract has not been entered into between the user and the manufacturer, the user purchases a transfer unit 5 separately, attaches it to the main body frame 2, and uses the image forming device 1. If a subscription contract has been entered into between the user and the manufacturer, the user attaches the transfer unit 5 delivered by the manufacturer of the transfer unit 5 to the main body frame 2 and uses the image forming device 1.

[0038] In this embodiment, a user can enter into one of two types of subscription contracts, a first contract or a second contract, with the manufacturer of the transfer unit 5. The first contract is a contract under which a regular transfer unit 5 (hereinafter referred to as the "first transfer unit") is delivered from the manufacturer. The second contract is a contract under which a transfer unit 5 (hereinafter referred to as the "second transfer unit") that is cheaper than the first transfer unit is delivered from the manufacturer.

[0039] The main body memory 82 stores contract information indicating whether or not there is a subscription contract as described above, or whether the type of subscription contract is a first contract or a second contract. Specifically, the main body memory 82 stores any of "normal," "first contract," and "second contract" as contract information. "Normal" is contract information indicating that the user has not concluded a subscription contract with the manufacturer of the transfer unit 5. "First contract" is contract information indicating that the user has concluded a first contract with the manufacturer of the transfer unit 5. "Second contract" is contract information indicating that the user has concluded a second contract with the manufacturer of the transfer unit 5.

[0040] <3. About transcription memory> As shown in FIGS. 1 and 2, the transfer unit 5 has a transfer memory 54. The transfer memory 54 is a storage medium from which information can be read and written. When the transfer unit 5 is attached to the main body frame 2, the transfer memory 54 is electrically connected to the control unit 8. As a result, the control unit 8 can read information from the transfer memory 54 and write information to the transfer memory 54.

[0041] The transfer memory 54 stores various information related to the transfer unit 5. Specifically, the transfer memory 54 stores the cumulative number of printed sheets, cumulative number of rotations, cumulative transfer value Σαx, cumulative belt value Σβ, sample time, sample count, and transfer unit type. However, the transfer memory 54 may store only a portion of this information.

[0042] The cumulative number of printed sheets indicates the number of sheets printed using the transfer unit 5 after the image forming apparatus 1 started using the transfer unit 5. The cumulative number of rotations indicates the number of rotations of the belt 52 after the image forming apparatus 1 started using the transfer unit 5. The transfer cumulative value Σαx indicates the cumulative value of current supplied from the current supply circuit 7 to the transfer roller 53 after the image forming apparatus 1 started using the transfer unit 5. The belt cumulative value Σβ indicates the cumulative value of current supplied from the current supply circuit 7 to the transfer roller 53 and the cleaning roller 61 after the image forming apparatus 1 started using the transfer unit 5. The sample time indicates the time interval for calculating the transfer cumulative value Σαx and the belt cumulative value Σβ in the periodic execution process described below. The sample count indicates the number of times the transfer cumulative value Σαx and the belt cumulative value Σβ are calculated in the periodic execution process described below. The transfer unit type indicates whether the transfer unit 5 is the "first transfer unit" or the "second transfer unit" described above.

[0043] <4. Processing of the control section> Next, the process executed by the control unit 8 in the image forming apparatus 1 will be described.

[0044] <4-1. Initial processing> First, the initial processing executed by the control unit 8 when the power of the image forming apparatus 1 is switched from off to on or when the cover 22 of the image forming apparatus 1 is closed will be described. Fig. 3 is a flowchart showing the flow of the initial processing. In this embodiment, it is assumed that the cleaning unit 6 and the transfer unit 5 are attached to the main body frame 2 and the drum unit 4 with four developer cartridges 3 attached is attached to the main body frame 2 at the start of the initial processing in Fig. 3.

[0045] First, the control unit 8 detects that the power of the image forming apparatus 1 has been switched from off to on or that the cover 22 of the image forming apparatus 1 has been closed (step S11). For example, when the supply of current to the control unit 8 starts, the control unit 8 determines that the power has been switched from off to on. Furthermore, when the control unit 8 receives a detection signal from the cover sensor 23, it determines that the cover 22 has been closed.

[0046] When the control unit 8 detects that the power has been switched from off to on or that the cover 22 of the image forming apparatus 1 has been closed (step S11: yes), the control unit 8 then executes latch processing (step S12). The latch processing is a process in which the control unit 8 reads information from the transfer memory 54.

[0047] 4 is a flowchart showing the detailed flow of the latch process. As shown in FIG. 4, the control unit 8 executes the following operations from the transfer memory 54: reading the cumulative number of printed sheets (step S21), reading the cumulative number of rotations (step S22), reading the cumulative transfer value Σαx (step S23), reading the cumulative belt value Σβ (step S24), reading the sample time (step S25), reading the sample count (step S26), and reading the transfer unit type (step S27). The control unit 8 then writes the read cumulative number of printed sheets, cumulative number of rotations, cumulative transfer value Σαx, cumulative belt value Σβ, sample time, sample count, and transfer unit type to the main body memory 82.

[0048] Note that steps S21 to S27 may be executed in any order different from that shown in FIG.

[0049] When the latching process is completed, the control unit 8 reads out the contract information and the transfer unit type stored in the main body memory 82. Then, the control unit 8 sets the usage mode of the transfer unit 5 based on the read out contract information and transfer unit type (step S13).

[0050] FIG. 5 is a diagram showing an example of Table T, which shows the relationship between contract information, transfer unit type, and the usage mode of the transfer unit 5. Table T specifies three usage modes according to the contract information and transfer unit type: "usable and extendable," "usable and not extendable," and "unusable." "Usable and extendable" indicates that the transfer unit 5 can be used, and that even if the transfer unit 5 reaches the end of its life, it can be extended and used. "Usable and not extendable" indicates that the transfer unit 5 can be used, but if the transfer unit 5 reaches the end of its life, it cannot be extended and used. "Unusable" indicates that the transfer unit 5 cannot be used.

[0051] Table T is pre-stored in the main body memory 82. The control unit 8 reads out Table T from the main body memory 82, and sets the usage mode of the transfer unit 5 based on Table T, the contract information, and the belt type described above.

[0052] In the example of FIG. 5, when the transfer unit type is the "first transfer unit," or when the transfer unit type is the "second transfer unit" and the contract information is the "second contract," the control unit 8 sets the usage mode to "usable and extendable." In this case, the control unit 8 writes in the main body memory 82 that the usage mode is "usable and extendable." Also, when the transfer unit type is the "second transfer unit" and the contract information is the "first contract," the control unit 8 sets the usage mode to "usable and not extendable." In this case, the control unit 8 writes in the main body memory 82 that the usage mode is "usable and not extendable."

[0053] Furthermore, if the transfer unit type is "second transfer unit" and the contract information is "normal," the control unit 8 sets the usage mode to "unusable." In this case, the control unit 8 writes the usage mode to the main body memory 82, indicating that the usage mode is "unusable." In addition, in this case, the control unit 8 displays an error on the display 9. Specifically, the control unit 8 displays a message on the display 9 indicating that the transfer unit 5 is unusable.

[0054] The relationship between the contract information and the type of transfer unit and the use mode of the transfer unit 5 is not limited to the example shown in FIG.

[0055] Next, the control unit 8 checks the remaining life of the transfer unit 5 (step S14, life determination process). Specifically, the control unit 8 calculates the remaining life of the transfer unit 5 based on the cumulative number of printed sheets, cumulative number of rotations, cumulative transfer value Σαx, and cumulative belt value Σβ read in the latch process of step S12. If the calculated remaining life is shorter than a preset threshold, the control unit 8 determines that the remaining life of the transfer unit 5 is short or that the transfer unit 5 has reached the end of its life. Details of the life determination process will be described later.

[0056] If it is determined in the lifespan determination process of step S14 that the lifespan is still remaining, the control unit 8 waits for input of a print instruction (step S15).

[0057] <4-2.Regular Processing> Next, a description will be given of the periodic execution process that is repeatedly executed at predetermined time intervals by the control unit 8 after the above-described initial process is completed. Fig. 6 is a flowchart showing the flow of the periodic execution process.

[0058] <4-2-1. Print count processing> First, the control unit 8 counts the cumulative number of printed sheets (step S31, printed sheet count process). Fig. 7 is a flowchart showing the flow of the printed sheet count process.

[0059] In the print count process, first, the control unit 8 determines whether or not one print process has been executed (step S41). If the control unit 8 determines that no print process has been executed (step S41: no), the control unit 8 ends the print count process.

[0060] On the other hand, if the control unit 8 determines in step S41 that printing processing for one sheet has been executed (step S41: yes), the control unit 8 updates the cumulative number of printed sheets stored in the main memory 82 (step S42). Specifically, the control unit 8 increments the cumulative number of printed sheets stored in the main memory 82. Then, the control unit 8 writes the updated cumulative number of printed sheets to the transfer memory 54 (step S43).

[0061] <4-2-2. Belt rotation count processing> Next, the control unit 8 counts the cumulative number of rotations (step S32, belt rotation count process). FIG. 8 is a flowchart showing the flow of the belt rotation count process. In the belt rotation count process, the control unit 8 first determines whether the belt 52 is rotating (step S51). If the control unit 8 determines that the belt 52 is rotating (step S51: yes), the control unit 8 then determines whether the belt 52 has made one rotation (step S52). If the control unit 8 determines that the belt 52 has not made one rotation (step S52: no), the control unit 8 ends the belt rotation count process.

[0062] On the other hand, if the control unit 8 determines in step S52 that the belt 52 has made one rotation, the control unit 8 updates the cumulative number of rotations stored in the main memory 82 (step S53). Specifically, the control unit 8 increments the cumulative number of rotations stored in the main memory 82. Then, the control unit 8 determines whether the cumulative number of rotations has increased by a predetermined amount or more since the previous writing of the cumulative number of rotations to the transfer memory 54 (step S54). If the control unit 8 determines that the cumulative number of rotations has not increased by a predetermined amount or more since the previous writing of the cumulative number of rotations to the transfer memory 54 (step S54: no), the control unit 8 ends the belt rotation number counting process.

[0063] On the other hand, in step S54, if the control unit 8 determines that the cumulative rotation count has increased by more than a predetermined amount since the previous time the cumulative rotation count was written to the transfer memory 54 (step S54: yes), the control unit 8 writes the updated cumulative rotation count to the main memory 82 (step S55).

[0064] Furthermore, if the control unit 8 determines in step S51 that the belt 52 is not rotating (step S51: no), the control unit 8 determines whether the cumulative number of rotations has been updated (step S56). For example, if the previous belt rotation count process in step S54 proceeds to no and the current belt rotation count process in step S51 proceeds to no, the cumulative number of rotations has been updated. If the control unit 8 determines that the cumulative number of rotations has been updated (step S56: yes), the control unit 8 writes the updated cumulative number of rotations to the transfer memory 54 (step S55). On the other hand, if the control unit 8 determines in step S56 that the cumulative number of rotations has not been updated (step S56: no), the control unit 8 ends the belt rotation count process.

[0065] <4-2-3. Cumulative transfer value calculation process> Next, the control unit 8 calculates the transfer cumulative value Σαx, which is one of the indices for determining the wear level of the transfer unit 5 (step S33, transfer cumulative value calculation process). Fig. 9 is a flowchart showing the flow of the transfer cumulative value calculation process.

[0066] In the transfer cumulative value calculation process, first, the control unit 8 determines whether or not the current supply circuit 7 is currently supplying current to the transfer roller 53 (step S61). If the control unit 8 determines that the current supply circuit 7 is currently supplying current to the transfer roller 53 (step S61: yes), the control unit 8 calculates the elapsed time of the current supply from the current supply circuit 7 to the transfer roller 53 (step S62).

[0067] Next, the control unit 8 determines whether the elapsed time since the current supply circuit 7 supplied current to the transfer roller 53 has reached the sample time (step S63). If the control unit 8 determines that the elapsed time since the current supply circuit 7 supplied current to the transfer roller 53 has not reached the sample time (step S63: no), the control unit 8 ends the transfer cumulative value calculation process.

[0068] On the other hand, in step S63, if the control unit 8 determines that the elapsed time of current supply from the current supply circuit 7 to the transfer roller 53 has reached the sample time (step S63: yes), the control unit 8 calculates the transfer parameter αx based on the current value being supplied from the current supply circuit 7 to the transfer roller 53 (step S64: transfer parameter calculation process).

[0069] Specifically, assuming that the current value supplied to the transfer roller 53 is Ix, the sampling time is Tx, and the coefficient is Ax, the control unit 8 calculates the transfer parameter αx using the following formula (1). αx=Ax×Ix×Tx (1)

[0070] In the above formula (1), x represents the color of the toner. That is, x is one of cyan (c), magenta (m), yellow (y), and black (k). The control unit 8 calculates the transfer parameter αc for the cyan transfer roller 53, the transfer parameter αm for the magenta transfer roller 53, the transfer parameter αy for the yellow transfer roller 53, and the transfer parameter αk for the black transfer roller 53 using the following formulas. αc=Ac×Ic×Tc (1c) αm=Am×Im×Tm (1m) αy=Ay×Iy×Ty (1y) αk=Ak×Ik×Tk (1k)

[0071] Next, the control unit 8 calculates the transfer cumulative value Σαx (step S65). The transfer cumulative value Σαx is the cumulative value of the transfer parameter αx. The control unit 8 calculates the transfer cumulative value Σαx by adding the transfer parameter αx measured in the current step S64 to the transfer cumulative value Σαx calculated in the previous step S65.

[0072] The control unit 8 calculates the above-mentioned transfer cumulative value Σαx for each transfer roller 53. Specifically, the control unit 8 calculates a transfer cumulative value Σαc for the cyan transfer roller 53, a transfer cumulative value Σαm for the magenta transfer roller 53, a transfer cumulative value Σαy for the yellow transfer roller 53, and a transfer cumulative value Σαk for the black transfer roller 53. Then, the control unit 8 writes the calculated transfer cumulative value Σαx to the main body memory 82.

[0073] Furthermore, the control unit 8 updates the sample count (step S66). Specifically, the control unit 8 increments the sample count. Then, the control unit 8 writes the updated sample count into the main memory 82. Note that step S66 may be executed before steps S64 and S65.

[0074] Thereafter, the control unit 8 determines whether the sample count has been updated by a predetermined amount or more since the previous writing of the sample count to the transfer memory 54 (step S67). If it is determined that the sample count has not been updated by a predetermined amount or more since the previous writing of the sample count to the transfer memory 54 (step S67: no), the control unit 8 ends the transfer cumulative value calculation process.

[0075] On the other hand, if the control unit 8 determines that the sample count has been updated by a predetermined amount or more since the previous writing of the sample count to the transfer memory 54 (step S67: yes), the control unit 8 writes the transfer cumulative value Σαx calculated in step S65 to the transfer memory 54 (step S68, transfer cumulative value writing process). Also, the control unit 8 writes the sample count updated in step S66 to the transfer memory 54 (step S69). The order of steps S68 and S69 may be reversed.

[0076] Furthermore, when the control unit 8 determines in step S61 that the current supply from the current supply circuit 7 to the transfer roller 53 is not being executed (step S61: no), the control unit 8 determines whether the sample count has been updated (step S70). For example, if the previous transfer cumulative value calculation process in step S67 proceeds to no and the current transfer cumulative value calculation process in step S61 proceeds to no, the sample count has been updated. In this case, the transfer cumulative value Σαx has also been updated.

[0077] If the control unit 8 determines in step S70 that the sample count has been updated (step S70: yes), it writes the updated transfer cumulative value Σαx and the updated sample count to the transfer memory 54 (steps S68, S69). On the other hand, if the control unit 8 determines in step S70 that the sample count has not been updated (step S70: no), it ends the transfer cumulative value calculation process.

[0078] <4-2-4. Belt cumulative value calculation process> Next, the control unit 8 calculates a belt cumulative value Σβ, which is one of the indices for determining the wear level of the transfer unit 5 (step S34, belt cumulative value calculation process). Fig. 10 is a flowchart showing the flow of the belt cumulative value calculation process.

[0079] In the belt cumulative value calculation process, first, the control unit 8 determines whether or not the current supply circuit 7 is currently supplying current to the transfer roller 53 and the cleaning roller 61 (step S71). If the control unit 8 determines that the current supply circuit 7 is currently supplying current to the transfer roller 53 and the cleaning roller 61 (step S71: yes), the control unit 8 calculates the elapsed time since the current supply circuit 7 has supplied current to the transfer roller 53 and the cleaning roller 61 (step S72).

[0080] Next, the control unit 8 determines whether the elapsed time since the current supply circuit 7 supplied current to the transfer roller 53 and the cleaning roller 61 has reached the sample time (step S73). If the control unit 8 determines that the elapsed time since the current supply circuit 7 supplied current to the transfer roller 53 and the cleaning roller 61 has not reached the sample time (step S73: no), the control unit 8 ends the belt cumulative value calculation process.

[0081] On the other hand, in step S63, if the control unit 8 determines that the elapsed time since the current supply circuit 7 supplied current to the transfer roller 53 and the cleaning roller 61 has reached the sample time (step S73: yes), the control unit 8 calculates the belt parameter β based on the transfer parameter αx calculated in step S64 of FIG. 9 and the current value supplied from the current supply circuit 7 to the cleaning roller 61 (step S74: belt parameter calculation process).

[0082] Specifically, the control unit 8 calculates the belt parameter β using the following formula (2) where Ib is the current value supplied to the cleaning roller 61, Tb is the sampling time, and B is the coefficient. The latest values ​​calculated in step S64 of the transfer cumulative value calculation process are used for the transfer parameters αc, αm, αy, and αk. β=αc+αm+αy+αk+B×Ib×Tb (2)

[0083] The belt parameter β is a parameter that reflects the total value of the current value supplied from the current supply circuit 7 to the cleaning roller 61 and the current value supplied from the current supply circuit 7 to the four transfer rollers 53.

[0084] Next, the control unit 8 calculates a belt cumulative value Σβ (step S75). The belt cumulative value Σβ is a cumulative value of the belt parameter β. The control unit 8 calculates the belt cumulative value Σβ by adding the belt parameter β measured in the current step S74 to the belt cumulative value Σβ calculated in the previous step S75. Then, the control unit 8 writes the calculated belt cumulative value Σβ to the main body memory 82.

[0085] Furthermore, the control unit 8 updates the sample count (step S76). Specifically, the control unit 8 increments the sample count. Then, the control unit 8 writes the updated sample count into the main memory 82. Note that step S76 may be executed before steps S74 and S75.

[0086] Thereafter, the control unit 8 determines whether the sample count has been updated by a predetermined amount or more since the previous writing of the sample count to the transfer memory 54 (step S77). If it is determined that the sample count has not been updated by a predetermined amount or more since the previous writing of the sample count to the transfer memory 54 (step S77: no), the control unit 8 ends the belt cumulative value calculation process.

[0087] On the other hand, if the control unit 8 determines that the sample count has been updated by a predetermined amount or more since the previous writing of the sample count to the transfer memory 54 (step S77: yes), the control unit 8 writes the belt cumulative value Σβ calculated in step S75 to the transfer memory 54 (step S78, belt cumulative value writing process). Also, the control unit 8 writes the sample count updated in step S76 to the transfer memory 54 (step S79). The order of steps S78 and S79 may be reversed.

[0088] Furthermore, when the control unit 8 determines in step S71 that the current supply circuit 7 is not currently supplying current to the transfer roller 53 and the cleaning roller 61 (step S71: no), the control unit 8 determines whether the sample count has been updated (step S80). For example, if the previous belt cumulative value calculation process in step S77 proceeds to no, and the current belt cumulative value calculation process in step S71 proceeds to no, the sample count has been updated. In this case, the belt cumulative value Σβ has also been updated.

[0089] If the control unit 8 determines in step S80 that the sample count has been updated (step S80: yes), it writes the updated belt cumulative value Σβ and the updated sample count to the transfer memory 54 (steps S78 and S79). On the other hand, if the control unit 8 determines in step S80 that the sample count has not been updated (step S70: no), it ends the belt cumulative value calculation process.

[0090] <4-2-5. Lifespan determination process> Returning to FIG. 6, the control unit 8 may execute the processes of steps S31 to S34 described above in any order. After steps S31 to S34 are completed, the control unit 8 determines whether at least one of the cumulative number of printed sheets, the cumulative number of rotations, the cumulative transfer value Σαx, and the cumulative belt value Σβ has been updated (step S35). If the control unit 8 determines that all of the cumulative number of printed sheets, the cumulative number of rotations, the cumulative transfer value Σαx, and the cumulative belt value Σβ have not been updated (step S35: no), the control unit 8 ends the regular execution process.

[0091] On the other hand, in step S35, if the control unit 8 determines that at least one of the cumulative number of printed sheets, the cumulative number of rotations, the cumulative transfer value Σαx, and the cumulative belt value Σβ has been updated (step S35: yes), the control unit 8 determines the lifespan of the transfer unit 5 (step S36, lifespan determination process). Specifically, the control unit 8 calculates the remaining lifespan of the transfer unit 5 based on the cumulative number of printed sheets, the cumulative number of rotations, the cumulative transfer value Σαx, and the cumulative belt value Σβ. Then, if the calculated lifespan is shorter than a preset threshold, the control unit 8 determines that the remaining lifespan of the transfer unit 5 is short or that the transfer unit 5 has reached its end of life.

[0092] 11 and 12 are flowcharts showing the detailed flow of the lifespan determination process in steps S14 and S36.

[0093] When executing the lifespan determination process, the control unit 8 calculates a first lifespan L1 indicating the remaining lifespan of the transfer unit 5 based on the belt cumulative value Σβ (step S81). First, the control unit 8 calculates the belt wear amount by multiplying the sample time by the belt cumulative value Σβ. The main body memory 82 stores in advance a belt wear amount, which is an upper limit value of the belt wear amount. The control unit 8 calculates the first lifespan L1 based on the belt cumulative value Σβ, for example, using the following formula (3). That is, the control unit 8 calculates the remaining value obtained by subtracting the belt wear amount from the belt lifespan wear amount, as a percentage of the belt lifespan wear amount, as the first lifespan L1. L1 (%) = 100 - {(belt wear amount / belt life wear amount) × 100} (3)

[0094] Furthermore, the control unit 8 calculates a second life L2 indicating the remaining life of the transfer unit 5 based on the transfer cumulative value Σαx (step S82). First, the control unit 8 calculates the transfer wear amount by multiplying the sample time by the transfer cumulative value Σαx. The main body memory 82 stores in advance a transfer wear amount, which is an upper limit value of the transfer wear amount. The control unit 8 calculates the second life L2 based on the transfer cumulative value Σαx, for example, using the following formula (4). That is, the control unit 8 calculates the remaining value obtained by subtracting the transfer wear amount from the transfer cumulative value Σαx, as a percentage of the transfer wear amount, as the second life L2. L2 (%) = 100 - {(transfer wear amount / transfer life wear amount) × 100} (4)

[0095] The control unit 8 calculates the second life L2 using the above method for each of the four transfer rollers 53. Then, the minimum value of the four calculated second lives L2 is set as the calculation result of the second life L2.

[0096] Furthermore, the control unit 8 calculates a third life L3 indicating the remaining life of the transfer unit 5 based on the cumulative number of rotations of the belt 52 (step S83). A life rotation count, which is an upper limit value for the number of rotations of the belt 52, is stored in advance in the main body memory 82. The control unit 8 calculates the third life L3 based on the cumulative rotation count, for example, using the following formula (5). That is, the control unit 8 calculates the remaining number of rotations, which is obtained by subtracting the cumulative rotation count from the life rotation count, as a percentage of the life rotation count, as the third life L3. L3(%) = 100 - {(cumulative rotations / lifetime rotations) × 100} (5)

[0097] The control unit 8 also calculates a fourth life L4 indicating the remaining life of the transfer unit 5 based on the cumulative number of pages printed by the transfer unit 5 (step S84). A lifetime print count, which is the upper limit of the number of pages printed using the transfer unit 5, is stored in advance in the main unit memory 82. The control unit 8 calculates the fourth life L4 based on the cumulative number of pages printed, for example, using the following formula (6). That is, the control unit 8 calculates the remaining number of pages printed, which is obtained by subtracting the cumulative number of pages printed from the lifetime print count, as a percentage of the lifetime print count, as the fourth life L4. L4(%) = 100 - {(cumulative number of prints / lifetime number of prints) x 100} (5)

[0098] The control unit 8 may execute the processes of steps S81 to S84 in any order. The control unit 8 may also calculate the remaining lives L1, L2, L3, and L4 using a calculation method different from the above.

[0099] When the processing of steps S81 to S84 is completed, the control unit 8 determines the minimum life, which is the shortest life among the first life L1, the second life L2, the third life L3, and the fourth life L4, as the remaining life of the transfer unit 5 (step S85: life determination processing).

[0100] 12. After step S85, the control unit 8 determines whether the minimum lifespan is smaller than a preset first threshold value (step S86). If the control unit 8 determines that the minimum lifespan is equal to or greater than the first threshold value (step S86: no), the control unit 8 ends the lifespan determination process. In this case, since there is sufficient remaining lifespan, the control unit 8 does not display a message regarding the lifespan on the display 9.

[0101] On the other hand, if the control unit 8 determines in step S86 that the minimum life is shorter than the first threshold value (step S86: yes), then the control unit 8 determines whether the minimum life is shorter than a preset second threshold value (step S87). The second threshold value is a threshold value smaller than the first threshold value. If the control unit 8 determines that the minimum life is equal to or greater than the second threshold value (step S87: no), the control unit 8 displays a warning on the display 9. Specifically, the control unit 8 displays a message on the display 9 indicating that the remaining life of the transfer unit 5 is short (step S88: first display step).

[0102] On the other hand, in step S87, if the control unit 8 determines that the minimum life is shorter than the second threshold value (step S87: yes), the control unit 8 displays a warning on the display 9. Specifically, the control unit 8 displays a message on the display 9 indicating that the transfer unit 5 has reached the end of its life (step S89: second display step).

[0103] After step S89, the control unit 8 reads out the usage mode stored in the main body memory 82. Then, the control unit 8 determines whether the usage mode is "usable and extendable" or "usable and not extendable" (step S90).

[0104] If the control unit 8 determines that the usage mode is "usable / extendable" (step S89: yes), it permits extended use of the transfer unit 5 (step S91). That is, the control unit 8 waits for the input of the next print instruction.

[0105] In this way, when the transfer unit 5 is used for an extended period of time, the resistance value of the transfer roller 53 may be higher than normal. If the resistance value of the transfer roller 53 is high, the voltage value of the transfer roller 53 when the same current is supplied will be higher than if the resistance value of the transfer roller 53 is low. For this reason, when the transfer unit 5 is used for an extended period of time, the control unit 8 may reduce the current value supplied from the current supply circuit 7 to the transfer roller 53. This prevents the voltage value of the transfer roller 53 from becoming excessive.

[0106] On the other hand, in step S90, if the control unit 8 determines that the usage mode is "usable / unextendable" (step S90: no), the control unit 8 prohibits extended use of the transfer unit 5. In this case, the control unit 8 displays a warning on the display 9 (step S92). Specifically, the control unit 8 displays a message on the display 9 urging the user to replace the transfer unit 5. The control unit 8 will not execute printing until the transfer unit 5 is replaced with a new transfer unit 5.

[0107] As described above, in this image forming apparatus 1, the control unit 8 calculates the amount of wear of the transfer unit 5 based on the cumulative value of the current supplied from the current supply circuit 7 to the cleaning roller 61. This makes it possible to determine the amount of wear of the transfer unit 5, taking into account the deterioration of the belt 52 caused by the supply of current to the cleaning roller 61.

[0108] Furthermore, in this image forming apparatus 1, the control unit 8 calculates the amount of wear of the transfer unit 5 based on the cumulative value of the current supplied from the current supply circuit 7 to the transfer roller 53 and the cumulative value of the current supplied from the current supply circuit 7 to the cleaning roller 61. This makes it possible to determine the amount of wear of the transfer unit 5, taking into account the deterioration of the belt 52 caused by both the current supply to the transfer roller 53 and the current supply to the cleaning roller 61.

[0109] Furthermore, in this image forming apparatus 1, the control unit 8 stores the calculated transfer cumulative value Σαx and belt cumulative value Σβ in the transfer memory 54 of the transfer unit 5. In this way, even if the transfer unit 5 that has once been put into use is removed from the main body frame 2 and attached to the main body frame 2 of another image forming apparatus 1, the other image forming apparatus 1 can read out the transfer cumulative value Σαx and belt cumulative value Σβ from the transfer memory 54. Therefore, the control unit 8 of the other image forming apparatus 1 can appropriately determine the remaining life of the transfer unit 5 based on the read-out transfer cumulative value Σαx and belt cumulative value Σβ.

[0110] Furthermore, in this image forming apparatus 1, the control unit 8 sets the usage mode of the transfer unit 5 based on the transfer unit type read from the transfer memory 54. Then, when the control unit 8 determines that the transfer unit 5 has reached the end of its life, it permits or prohibits extended use of the transfer unit 5 in accordance with the usage mode. This makes it possible to appropriately permit or prohibit extended use of the transfer unit 5 depending on the type of the transfer unit 5.

[0111] Furthermore, in this image forming apparatus 1, the control unit 8 sets the usage mode of the transfer unit 5 based on the contract information read from the main body memory 82. Then, when the control unit 8 determines that the transfer unit 5 has reached the end of its life, it permits or prohibits extended use of the transfer unit 5 in accordance with the usage mode. This makes it possible to appropriately permit or prohibit extended use of the transfer unit 5 in accordance with the contract information.

[0112] <5. Variations> Although one embodiment of the present disclosure has been described above, the present disclosure is not limited to the above embodiment. Various modifications will be described below, focusing on differences from the above embodiment.

[0113] In the above embodiment, the control unit 8 calculates the first life L1, the second life L2, the third life L3, and the fourth life L4, and determines the remaining life of the transfer unit 5 based on the smallest of these. However, the control unit 8 does not necessarily have to calculate all four types of life L1 to L4. For example, the control unit 8 may calculate only the first life L1 without calculating the second life L2, the third life L3, and the fourth life L4, and determine the remaining life of the transfer unit 5 based only on the first life L1.

[0114] In the above embodiment, the sample time is stored in the transfer memory 54. However, the sample time may be stored in advance in the main memory 82 instead of the transfer memory 54.

[0115] Furthermore, in the above embodiment, the control unit 8 displayed a message on the display 9 in step S88 indicating that the remaining life of the transfer unit 5 is short, regardless of the contract information. However, the control unit 8 may change whether or not to display the message in step S88 depending on the contract information. For example, if a subscription contract has been concluded, the user does not need to prepare a new transfer unit 5 in preparation for the transfer unit 5 reaching the end of its life. Therefore, if the contract information is "first contract" or "second contract," the control unit 8 may not need to display a message on the display 9 in step S88 indicating that the remaining life of the transfer unit 5 is short.

[0116] The image forming apparatus of the above embodiment includes a current supply circuit 7 that supplies current to the transfer roller 53 and the cleaning roller 61. This current supply circuit 7 may include a plurality of different electric circuits. For example, the current supply circuit 7 may include a first circuit that supplies current to the transfer roller 53 and a second circuit that supplies current to the cleaning roller 61, as separate circuits.

[0117] In the above embodiment, the number of developer cartridges 3 mounted on the drum unit 4 is four. However, the number of developer cartridges 3 mounted on the drum unit 4 may be one to three, or five or more. The number of transfer rollers 53 included in the transfer unit 5 may also be one to three, or five or more.

[0118] In the above embodiment, the transfer unit 5 and the cleaning unit 6 are separate entities. However, the transfer unit 5 and the cleaning unit 6 may be integrated. For example, the transfer unit 5 may have a cleaning roller 61 and a waste toner box 62.

[0119] In the above embodiment, the drum unit 4 and the transfer unit 5 are separate entities. However, the drum unit 4 and the transfer unit 5 may be integrated. For example, the drum unit 4 may have a belt 52 and a transfer roller 53. In this case, the control unit 8 may treat the remaining life of the transfer unit 5 calculated by the above method as the life of the drum unit 4.

[0120] In the above embodiment, the developer cartridge 3 and the transfer unit 5 are separate entities. However, the developer cartridge 3 and the transfer unit 5 may be integrated. For example, the developer cartridge 3 may have a belt 52 and a transfer roller 53. In this case, the control unit 8 may treat the remaining life of the transfer unit 5 calculated by the above-described method as the life of the developer cartridge 3.

[0121] Furthermore, the detailed shapes of the components constituting the image forming apparatus 1 and the details of the processes executed by the control unit 8 may be changed as appropriate. Furthermore, the elements appearing in the above-described embodiment and modified examples may be selected as appropriate within the scope of not causing any contradiction. [Explanation of symbols]

[0122] 1: Image forming device 2: Main frame 3: Developing cartridge 4: Drum unit 5: Transcription unit 6: Cleaning unit 7: Current supply circuit 8: Control section 9: Display 31: Developing roller 41: Photosensitive drum 52: Belt 53: Transfer roller 54: Transfer Memory 61: Cleaning roller T: Table

Claims

1. A photosensitive drum; A replaceable transfer unit, A transfer roller; Belt and a transcription unit having a cleaning roller for cleaning the belt; a current supply circuit for supplying a current to the cleaning roller; a control unit electrically connected to the current supply circuit; Equipped with The control unit 10. An image forming apparatus, comprising: a current supply circuit for supplying a current to said cleaning roller; a current supply circuit for supplying a current to said cleaning roller;

2. 2. The image forming apparatus according to claim 1, the current supply circuit also supplies current to the transfer roller; The control unit calculates the amount of wear of the transfer unit based on the cumulative value of the current value supplied from the current supply circuit to the transfer roller and the cumulative value of the current value supplied from the current supply circuit to the cleaning roller.

3. 3. The image forming apparatus according to claim 2, The control unit a belt cumulative value calculation process that is periodically performed to calculate a belt parameter that is a sum of a current value supplied from the current supply circuit to the cleaning roller and a current value supplied from the current supply circuit to the transfer roller, and calculates a belt cumulative value that is a cumulative value of the belt parameter; a first life calculation process for calculating a first life indicating a remaining life of the transfer unit based on the belt cumulative value; An image forming apparatus comprising:

4. 4. The image forming apparatus according to claim 3, The control unit a transfer cumulative value calculation process that is periodically performed and calculates a transfer parameter based on a current value supplied from the current supply circuit to the transfer roller, and calculates a transfer cumulative value that is a cumulative value of the transfer parameter; a second life calculation process for calculating a second life indicating a remaining life of the transfer unit based on the transfer cumulative value; The image forming apparatus further comprises:

5. 5. The image forming apparatus according to claim 4, The control unit a third life calculation process for calculating a third life indicating a remaining life of the transfer unit based on the cumulative number of rotations of the belt; a fourth life calculation process for calculating a fourth life indicating a remaining life of the transfer unit based on the cumulative number of printed sheets by the transfer unit; a lifespan determination process for determining the smallest of the first lifespan, the second lifespan, the third lifespan, and the fourth lifespan as the remaining lifespan of the transfer unit; The image forming apparatus further comprises:

6. 6. The image forming apparatus according to claim 5, display Furthermore, The control unit a display step of displaying a warning on the display when the minimum lifespan is less than a threshold value; The image forming apparatus further comprises:

7. 6. The image forming apparatus according to claim 5, The image forming apparatus is characterized in that the control unit reduces a value of the current supplied from the current supply circuit to the transfer roller when the minimum life is less than a threshold value.

8. 8. The image forming apparatus according to claim 4, wherein: The transfer unit comprises: a transfer memory for storing the belt cumulative value and the transfer cumulative value; The image forming apparatus further comprises:

9. 8. The image forming apparatus according to claim 4, wherein: the transfer unit has a plurality of the transfer rollers, The image forming apparatus is characterized in that the control unit calculates the transfer cumulative value for each of the transfer rollers.

Images