Image forming apparatus

Abstract

To provide a technique that can reduce the amount of information to be stored in a memory of a developing cartridge.SOLUTION: A voltage to be supplied to developing rollers 12, 22 itself is not stored in developing memories 13, 14 of developing cartridges 10, 20, but a change rate and an intercept are stored in the developing memories. A control unit 40 of an image forming apparatus 1 reads the change rate and intercept from the developing memories 13, 23, and calculates a voltage value according to the number of prints on the basis of the change rate and intercept. The amount of information to be stored in the memories 13, 23 can thus be reduced.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Conventionally, electrophotographic image forming devices such as laser printers and LED printers are known. The image forming device has a developer cartridge. The developer cartridge is attachable to the main body frame of the image forming device. The developer cartridge contains toner. The developer cartridge also has a developer roller for supplying the toner. The image forming device supplies a voltage to the developer roller. The electrostatic force generated by this voltage carries the toner on the outer peripheral surface of the developer roller.

[0003] A conventional image forming apparatus is described, for example, in Patent Document 1. The image forming apparatus of Patent Document 1 changes the voltage value supplied to the developing roller depending on the number of sheets to be printed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-292475 Summary of the Invention [Problem to be solved by the invention]

[0005] It is desirable to change the voltage value supplied to the developing roller depending on the specifications of the developing cartridge, for example, depending on the manufacturer of the developing roller, the number of times the developing roller has been recycled, or the toner capacity of the developing cartridge.

[0006] In order to change the voltage value according to the specifications of the developer cartridge, for example, it is possible to store the voltage value according to the specifications of the developer cartridge in a memory provided in the developer cartridge. In this way, the control unit of the image forming apparatus can read the voltage value according to the specifications of the developer cartridge from the memory. However, if all of the voltage values ​​that change as the number of prints increases are stored in the memory, the amount of information stored in the memory will be large.

[0007] An object of the present disclosure is to provide a technology that can reduce the amount of information stored in the memory of a developer cartridge. [Means for solving the problem]

[0008] The first disclosure of the present application is an image forming apparatus having a main body frame to which either a first developing cartridge or a second developing cartridge can be attached, wherein the first developing cartridge has a first developing roller and a first developing memory that stores a first rate of change and a first intercept that indicate a change in a first voltage value supplied to the first developing roller according to the number of printed sheets, and the second developing cartridge has a second developing roller and a second developing memory that stores a second rate of change and a second intercept that indicate a change in a second voltage value supplied to the second developing roller according to the number of printed sheets, the second rate of change being different from the first rate of change and the second intercept being different from the first intercept, and when the first developing cartridge is attached to the main body frame, the image forming apparatus is electrically connected to the first developing roller and the first developing memory. and a control unit that is electrically connected to the second developing roller and the second developing memory when the second developing cartridge is attached to the main frame, wherein when the first developing cartridge is attached to the main frame, the control unit reads the first change rate and the first intercept from the first developing memory, calculates the first voltage value based on the first change rate, the first intercept, and the number of prints, and supplies a voltage of the first voltage value to the first developing roller, and when the second developing cartridge is attached to the main frame, reads the second change rate and the second intercept from the second developing memory, calculates the second voltage value based on the second change rate, the second intercept, and the number of prints, and supplies a voltage of the second voltage value to the second developing roller.

[0009] The second disclosure of the present application is the image forming apparatus of the first disclosure, wherein the control unit has a main memory that stores a maximum voltage value that is an upper limit value of the first voltage value and the second voltage value, and the control unit supplies a voltage of the maximum voltage value to the first developing roller when the first voltage value calculated based on the first change rate, the first intercept, and the number of printed sheets is greater than the maximum voltage value, and supplies a voltage of the maximum voltage value to the second developing roller when the second voltage value calculated based on the second change rate, the second intercept, and the number of printed sheets is greater than the maximum voltage value.

[0010] The third disclosure of the present application is an image forming apparatus according to the first or second disclosure, wherein the control unit has a main memory that stores a minimum voltage value that is the lower limit of the first voltage value and the second voltage value, and the control unit supplies a voltage of the minimum voltage value to the first developing roller when the first voltage value calculated based on the first change rate, the first intercept, and the number of printed sheets is smaller than the minimum voltage value, and supplies a voltage of the minimum voltage value to the second developing roller when the second voltage value calculated based on the second change rate, the second intercept, and the number of printed sheets is smaller than the minimum voltage value.

[0011] A fourth disclosure of the present application is the image forming apparatus of any one of the first to third disclosures, characterized in that the first developing roller and the second developing roller are made by different manufacturers.

[0012] A fifth disclosure of the present application is the image forming apparatus of any one of the first to fourth disclosures, characterized in that the first developing roller and the second developing roller have different recycling counts.

[0013] The sixth disclosure of the present application is an image forming apparatus according to any one of the first to fifth disclosures, characterized in that the first developing cartridge and the second developing cartridge have different amounts of toner stored therein.

[0014] A seventh disclosure of the present application is an image forming apparatus according to any one of the first to sixth disclosures, characterized in that the first development memory stores multiple types of the first change rate and the first intercept according to the printing speed, and the control unit calculates the first voltage value based on the first change rate and the first intercept corresponding to the printing speed specified by the job.

[0015] The eighth disclosure of the present application is an image forming device according to any one of the first to seventh disclosures, characterized in that the control unit has a main memory that stores the number of prints, and the control unit updates the number of prints stored in the main memory when printing.

[0016] The ninth disclosure of the present application is an image forming apparatus according to any one of the first to eighth disclosures, wherein the first developing memory stores the number of pages printed by the first developing cartridge, the second developing memory stores the number of pages printed by the second developing cartridge, and the control unit updates the number of pages printed stored in the first developing memory when printing is performed with the first developing cartridge attached to the main frame, and updates the number of pages printed stored in the second developing memory when printing is performed with the second developing cartridge attached to the main frame.

[0017] The tenth disclosure of the present application is an image forming apparatus according to any one of the first to ninth disclosures, characterized in that the first developing memory stores the first voltage value, the second developing memory stores the second voltage value, and the control unit writes the first voltage value supplied to the first developing roller into the first developing memory when printing is performed with the first developing cartridge attached to the main body frame, and writes the second voltage value supplied to the second developing roller into the second developing memory when printing is performed with the second developing cartridge attached to the main body frame.

[0018] An eleventh disclosure of the present application is an image forming apparatus having a main body frame to which either a first developing cartridge or a second developing cartridge can be attached, wherein the first developing cartridge has a first developing roller and a first developing memory that stores specifications of the first developing cartridge, and the second developing cartridge has a second developing roller and a second developing memory that stores specifications of the second developing cartridge, and the image forming apparatus further comprises a control unit that is electrically connected to the first developing roller and the first developing memory when the first developing cartridge is attached to the main body frame, and is electrically connected to the second developing roller and the second developing memory when the second developing cartridge is attached to the main body frame, and the control unit is configured to control the first developing memory when the first developing cartridge is attached to the main body frame. and when the second developer cartridge is mounted in the main frame, the specification is read from the second developer memory, and based on the specification read from the first developer memory, a first change rate and a first intercept that indicate a change in a first voltage value to be supplied to the first developer roller in response to the number of prints is calculated, the first voltage value is calculated based on the first change rate, the first intercept, and the number of prints, and a voltage of the first voltage value is supplied to the first developer roller. When the second developer cartridge is mounted in the main frame, the specification is read from the second developer memory, and based on the specification read from the second developer memory, a second change rate and a second intercept that indicate a change in a second voltage value to be supplied to the second developer roller in response to the number of prints is calculated, the second voltage value is calculated based on the second change rate, the second intercept, and the number of prints, and a voltage of the second voltage value is supplied to the second developer roller. [Effects of the Invention]

[0019] According to the first to eleventh disclosures, the control unit calculates the first voltage value to be supplied to the first developing roller without storing the first voltage value itself in the first developing memory. This makes it possible to reduce the amount of information stored in the first developing memory. Also, the control unit calculates the second voltage value to be supplied to the second developing roller without storing the second voltage value itself in the second developing memory. This makes it possible to reduce the amount of information stored in the second developing memory.

[0020] According to the second disclosure, the main body memory stores the maximum voltage value, which makes it possible to further reduce the amount of information stored in the first and second developing memories.

[0021] According to the third disclosure, the main body memory stores the minimum voltage value, which makes it possible to further reduce the amount of information stored in the first and second developing memories.

[0022] Furthermore, according to the seventh disclosure, the first voltage value can be changed according to the printing speed. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a schematic diagram of an image forming apparatus. [Figure 2] FIG. 4 is a diagram showing information stored in a first development memory. [Figure 3] FIG. 10 is a diagram showing information stored in a second development memory. [Figure 4] FIG. 2 is a diagram showing information stored in a main body memory. [Figure 5] 10 is a flowchart showing the flow of a printing process. [Figure 6] 10 is a graph showing the correspondence relationship between the first number of printed sheets and the first voltage value. [Figure 7] 10 is a graph showing the correspondence relationship between the second number of printed sheets and the second voltage value. [Figure 8] FIG. 10 is a diagram showing information stored in a first development memory in a first modified example. [Figure 9] 10 is a flowchart showing the flow of a printing process according to a second modified example. [Figure 10] FIG. 11 is a diagram showing information stored in a first development memory in a third modified example. [Figure 11] FIG. 11 is a diagram showing information stored in a main body memory in a third modified example. [Figure 12] FIG. 10 is a diagram showing an example of a table. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, an embodiment of the present disclosure will be described. In the following description, the direction in which the rotation axis of the first developing roller 12 extends will be referred to as the "first direction."

[0025] <1. Configuration of image forming device> FIG. 1 is a schematic diagram of an image forming apparatus 1. The image forming apparatus 1 is an electrophotographic printer. Specifically, the image forming apparatus 1 is a laser printer or an LED printer. As shown in FIG. 1, the image forming apparatus 1 includes a main body frame 100, a first developing cartridge 10, a second developing cartridge 20, a drum cartridge 30, and a control unit 40.

[0026] 1, the drum cartridge 30 can be fitted with either the first developing cartridge 10 or the second developing cartridge 20. The drum cartridge 30 fitted with the first developing cartridge 10 or the second developing cartridge 20 can be fitted to the main body frame 100.

[0027] That is, when the first developing cartridge 10 is used, the first developing cartridge 10 is attached to the drum cartridge 30 and then attached to the main body frame 100. When the second developing cartridge 20 is used, the second developing cartridge 20 is attached to the drum cartridge 30 and then attached to the main body frame 100.

[0028] The first developing cartridge 10 has a first housing 11, a first developing roller 12, and a first developing memory 13. The first housing 11 is a container that contains toner. The first developing roller 12 is located at an end of the first housing 11. The first developing roller 12 is a roller that can rotate about a rotation axis that extends in a first direction. The toner is carried on the outer circumferential surface of the first developing roller 12. A portion of the outer circumferential surface of the first developing roller 12 is exposed to the outside of the first housing 11.

[0029] The first developing roller 12 has a first developing roller body 121 and a first developing roller shaft 122. The first developing roller body 121 is a cylindrical member extending in a first direction. The first developing roller body 121 is made of, for example, elastic rubber. The first developing roller shaft 122 is a cylindrical member that penetrates the first developing roller body 121 in the first direction. The first developing roller shaft 122 is made of, for example, metal or conductive resin. The first developing roller body 121 is fixed to the first developing roller shaft 122.

[0030] When the drum cartridge 30 with the first developing cartridge 10 attached thereto is mounted to the main body frame 100, the control unit 40 is electrically connected to the first developing roller shaft 122. The control unit 40 supplies a voltage to the first developing roller shaft 122. As a result, the toner is carried on the outer circumferential surface of the first developing roller 12 by electrostatic force caused by the voltage supplied to the first developing roller shaft 122. In other words, the control unit 40 has a voltage application circuit that applies a voltage to the first developing roller 12 when the first developing cartridge 10 is attached to the main body frame 100.

[0031] The first developing memory 13 is a storage medium from which information can be read and written. The first developing memory 13 stores information about the first developing cartridge 10.

[0032] FIG. 2 is a diagram showing information stored in the first developing memory 13. As shown in FIG. 2, the first developing memory 13 stores a first change rate A1, a first intercept B1, and a first number of prints X1. The first number of prints X1 is the cumulative number of prints using the first developing cartridge 10. The first change rate A1 and the first intercept B1 are values ​​that indicate the relationship between the first number of prints X1 and the first voltage value V1 supplied to the first developing roller 12. More specifically, the first voltage value V1 is expressed as a linear function of the first number of prints X1. The first change rate A1 is the slope of this linear function. The first intercept B1 is the first voltage value V1 when the first number of prints X1 is 0.

[0033] The second developing cartridge 20 has a second housing 21, a second developing roller 22, and a second developing memory 23. The second housing 21 is a container that contains toner. The second developing roller 22 is located at an end of the second housing 21. The second developing roller 22 is a roller that can rotate about a rotation axis that extends in the first direction. The toner is carried on the outer peripheral surface of the second developing roller 22. A portion of the outer peripheral surface of the second developing roller 22 is exposed to the outside of the second housing 21.

[0034] The second developing roller 22 has a second developing roller body 221 and a second developing roller shaft 222. The second developing roller body 221 is a cylindrical member extending in a first direction. The second developing roller body 221 is made of, for example, elastic rubber. The second developing roller shaft 222 is a cylindrical member that penetrates the second developing roller body 221 in the first direction. The second developing roller shaft 222 is made of, for example, metal or conductive resin. The second developing roller body 221 is fixed to the second developing roller shaft 222.

[0035] When the drum cartridge 30 with the second developer cartridge 20 attached thereto is mounted to the main body frame 100, the control unit 40 is electrically connected to the second developer roller shaft 222. The control unit 40 supplies a voltage to the second developer roller shaft 222. As a result, the toner is carried on the outer circumferential surface of the second developer roller 22 by electrostatic force caused by the voltage supplied to the second developer roller shaft 222. In other words, the control unit 40 has a voltage application circuit that applies a voltage to the second developer roller 22 when the second developer cartridge 20 is attached to the main body frame 100.

[0036] The second developing memory 23 is a storage medium from which information can be read and written. The second developing memory 23 stores information about the second developing cartridge 20.

[0037] FIG. 3 is a diagram showing information stored in the second development memory 23. As shown in FIG. 3, the second development memory 23 stores a second change rate A2, a second intercept B2, and a second number of prints X2. The second number of prints X2 is the cumulative number of prints using the second development cartridge 20. The second change rate A2 and the second intercept B2 are values ​​that indicate the relationship between the second number of prints X2 and the second voltage value V2 supplied to the second development roller 22. More specifically, the second voltage value V2 is expressed as a linear function of the second number of prints X2. The second change rate A2 is the slope of this linear function. The second intercept B2 is the second voltage value V2 when the second number of prints X2 is 0.

[0038] The first developing cartridge 10 and the second developing cartridge 20 have different specifications. For example, the manufacturer of the first developing roller 12 is different from the manufacturer of the second developing roller 22. Furthermore, for example, the number of times the first developing roller 12 has been recycled is different from the number of times the second developing roller 22 has been recycled. Furthermore, for example, the amount of toner contained inside the first developing cartridge 10 is different from the amount of toner contained inside the second developing cartridge 20.

[0039] If these specifications differ, the toner carrying performance of the first developing roller 12 and the toner carrying performance of the second developing roller 22 will differ. Furthermore, the change in performance relative to the number of printed sheets will also differ. Therefore, the first voltage value V1 supplied to the first developing roller shaft 122 and the second voltage value V2 supplied to the second developing roller shaft 222 must be different voltage values. Therefore, the first change rate A1 and the second change rate A2 are set to different values. Furthermore, the first intercept B1 and the second intercept B2 are set to different values.

[0040] The drum cartridge 30 has a photosensitive drum 31. The photosensitive drum 31 is rotatable about a rotation axis extending in a first direction. The photosensitive drum 31 has a cylindrical outer surface centered on the rotation axis. The outer surface of the photosensitive drum 31 is covered with a photosensitive material.

[0041] When the first developing cartridge 10 is attached to the drum cartridge 30, the first developing roller 12 comes into contact with the photosensitive drum 31. Specifically, the outer circumferential surface of the first developing roller 12 comes into contact with the outer circumferential surface of the photosensitive drum 31. The toner in the first housing 11 is supplied to the photosensitive drum 31 via the first developing roller 12.

[0042] When the second developing cartridge 20 is attached to the drum cartridge 30, the second developing roller 22 comes into contact with the photosensitive drum 31. Specifically, the outer circumferential surface of the second developing roller 22 comes into contact with the outer circumferential surface of the photosensitive drum 31. The toner in the second housing 21 is supplied to the photosensitive drum 31 via the second developing roller 22.

[0043] The control unit 40 is located within the main body frame 100 of the image forming apparatus 1. The control unit 40 has a processor 41 such as a CPU, and a main body memory 42. The main body memory 42 is a storage medium from which information can be read and written. The processor 41 can read information from the main body memory 42 and write information to the main body memory 42. The control unit 40 executes the printing process in the image forming apparatus 1 by the processor 41 operating in accordance with a program stored in the main body memory 42.

[0044] The image forming apparatus 1 has an electrode 101 in a main body frame 100. The electrode 101 is electrically connected to the control unit 40. When the drum cartridge 30 with the first developing cartridge 10 attached thereto is attached to the main body frame 100, the first developing memory 13 is electrically connected to the electrode 101. This electrically connects the first developing memory 13 to the control unit 40 via the electrode 101. As a result, the control unit 40 can read information from the first developing memory 13 and write information to the first developing memory 13.

[0045] Furthermore, when the drum cartridge 30 with the second developing cartridge 20 attached thereto is attached to the main body frame 100, the second developing memory 23 is electrically connected to the electrode 101. This electrically connects the second developing memory 23 to the control unit 40 via the electrode 101. As a result, the control unit 40 can read information from the second developing memory 23 and write information to the second developing memory 23.

[0046] 4 is a diagram showing information stored in the main memory 42. As shown in FIG. 4, the main memory 42 stores a maximum voltage value Vmax, a minimum voltage value Vmin, and the number of prints X. The maximum voltage value Vmax is the maximum value of the voltage supplied to the first developing roller 12 and the second developing roller 22. The minimum voltage value Vmin is the minimum value of the voltage supplied to the first developing roller 12 and the second developing roller 22.

[0047] The number of prints X is the cumulative number of prints made by the developer cartridge attached to the main body frame 100. When the drum cartridge 30 with the first developer cartridge 10 attached is attached to the main body frame 100, the number of prints X represents the first number of prints X1 made by the first developer cartridge 10. When the drum cartridge 30 with the second developer cartridge 20 attached is attached to the main body frame 100, the number of prints X represents the second number of prints X2 made by the second developer cartridge 20.

[0048] <2. Operation of image forming device> Next, a description will be given of the printing process performed by the image forming apparatus 1. Fig. 5 is a flowchart showing the flow of the printing process performed by the image forming apparatus 1.

[0049] When the first developing cartridge 10 is attached to the main body frame 100, the control unit 40 first reads out the first change rate A1 and the first intercept B1 from the first developing memory 13 (step S1). Next, the control unit 40 calculates the correspondence relationship between the first number of prints X1 by the first developing roller 12 and the first voltage value V1 supplied to the first developing roller shaft 122 based on the first change rate A1 and the first intercept B1 (step S2).

[0050] FIG. 6 is a graph showing the relationship between the first number of printed sheets X1 and the first voltage value V1. As the first number of printed sheets X1 increases, the toner becomes increasingly difficult to charge. Therefore, if the first voltage value V1 is constant, the amount of toner moving from the first developing roller 12 to the photosensitive drum 31 changes. As a result, the print density changes. Therefore, to maintain a constant print density, the first voltage value V1 is decreased as the first number of printed sheets X1 increases. Specifically, as shown in FIG. 6, the first voltage value V1 is set to a linear function expressed as V1 = B1 - A1 × X1.

[0051] However, even if the first print count X1 is small, there is an upper limit to the amount of charge on the toner. Therefore, the first voltage value V1 is also set to a maximum voltage value Vmax in accordance with the upper limit of the amount of charge on the toner. That is, as shown in Figure 6, if the value of B1 - A1 x X1 is greater than the maximum voltage value Vmax, the first voltage value V1 is set to the maximum voltage value Vmax.

[0052] Furthermore, even if the first print count X1 increases and the toner charge decreases, there is a lower limit to the toner charge. Therefore, the first voltage V1 also has a minimum voltage Vmin set to match the lower limit of the toner charge. That is, as shown in Figure 6, if the value of B1 - A1 x X1 is smaller than the minimum voltage Vmin, the first voltage V1 is set to the minimum voltage Vmin.

[0053] When the control unit 40 receives the print job, it performs printing in accordance with the print job. At that time, the control unit 40 calculates a first voltage value V1 corresponding to the first number of printed sheets X1 at that time based on the result calculated in step S2 (step S3). The control unit 40 then supplies the calculated first voltage value V1 to the first developing roller shaft 122 (step S4). This makes it possible to supply an appropriate voltage according to the charge amount of the toner to the first developing roller shaft 122. As a result, it is possible to suppress changes in print density as the first number of printed sheets X1 increases.

[0054] The control unit 40 updates the first number of prints X1 stored in the main memory 42 each time one printing is completed. Specifically, the control unit 40 increments the first number of prints X1 stored in the main memory 42. The control unit 40 also periodically writes the first number of prints X1 stored in the main memory 42 to the first developing memory 13 (step S5). This updates the first number of prints X1 stored in the first developing memory 13.

[0055] When the second developer cartridge 20 is attached to the main body frame 100, the control unit 40 performs the same processes as steps S1 to S5. Specifically, the control unit 40 reads the second change rate A2 and the second intercept B2 from the second development memory 23 (step S1), and calculates the correspondence relationship between the second number of prints X2 and the second voltage value V2 based on the second change rate A2 and the second intercept B2 (step S2). FIG. 7 is a graph showing the correspondence relationship between the second number of prints X2 and the second voltage value V2. When printing, the control unit 40 calculates the second voltage value V2 corresponding to the second number of prints X2 based on the correspondence relationship obtained in step S2 (step S3). The control unit 40 then supplies the calculated second voltage value V2 to the second development roller shaft 222 (step S4). The control unit 40 also periodically updates the second number of prints X2 stored in the second development memory 23 (step S5).

[0056] As described above, when the first developer cartridge 10 is attached to the main body frame 100, the image forming apparatus 1 calculates the first voltage value V1 corresponding to the first number of prints X1 based on the first change rate A1 and the first intercept B1. When the second developer cartridge 20 is attached to the main body frame 100, the image forming apparatus 1 calculates the second voltage value V2 corresponding to the second number of prints X2 based on the second change rate A2 different from the first change rate A1 and the second intercept B2 different from the first intercept B1. Therefore, an appropriate voltage according to the differences in specifications between the first developer cartridge 10 and the second developer cartridge 20 can be supplied to the developer roller shaft of each developer cartridge.

[0057] Furthermore, the first developing memory 13 stores the first change rate A1 and the first intercept B1 instead of storing a large number of first voltage values ​​V1 corresponding to the first number of prints X1. The control unit 40 then calculates the first voltage value V1 corresponding to the first number of prints X1 based on the first change rate A1 and the first intercept B1 read from the first developing memory 13. This reduces the amount of information stored in the first developing memory 13. Therefore, compared to storing a large number of first voltage values ​​V1 corresponding to the first number of prints X1 in the first developing memory 13, the storage capacity of the first developing memory 13 can be reduced. Furthermore, even if the number of terminals of the first developing memory 13 is small, the communication time is shorter when the amount of information stored in the first developing memory 13 is small compared to when the amount of information stored in the first developing memory 13 is large.

[0058] Furthermore, instead of storing a large number of second voltage values ​​V2 corresponding to the second number of prints X2 in the second developing memory 23, the second developing memory 23 stores the second change rate A2 and the second intercept B2. The control unit 40 then calculates the second voltage value V2 corresponding to the second number of prints X2 based on the second change rate A2 and the second intercept B2 read from the second developing memory 23. This reduces the amount of information stored in the second developing memory 23. Therefore, compared to storing a large number of second voltage values ​​V2 corresponding to the second number of prints X2 in the second developing memory 23, the storage capacity of the second developing memory 23 can be reduced. Furthermore, even if the number of terminals of the second developing memory 23 is small, communication time is shorter when the amount of information stored in the second developing memory 23 is small compared to when the amount of information stored in the second developing memory 23 is large.

[0059] Furthermore, in this embodiment, the maximum voltage value Vmax and the minimum voltage value Vmin are also stored in the main memory 42, rather than in the first developing memory 13 and the second developing memory 23. This allows the amount of information stored in the first developing memory 13 and the second developing memory 23 to be further reduced.

[0060] Furthermore, in this embodiment, when printing is performed with the first developer cartridge 10 attached to the main body frame 100, the control unit 40 writes the latest first number of prints X1 to the first development memory 13. This causes the latest first number of prints X1 to be stored in the first development memory 13. In this way, even if a first developer cartridge 10 that is being used is removed from the main body frame 100 and attached to the main body frame 100 of another image forming apparatus 1, the control unit 40 of the other image forming apparatus 1 can read the latest first number of prints X1 from the first development memory 13. Therefore, the control unit 40 of the other image forming apparatus 1 can calculate an appropriate first voltage value V1 based on the latest first number of prints X1.

[0061] Similarly, in this embodiment, when printing is performed with the second developer cartridge 20 attached to the main body frame 100, the control unit 40 writes the latest second number of prints X2 to the second development memory 23. This causes the latest second number of prints X2 to be stored in the second development memory 23. In this way, even if a second developer cartridge 20 that is being used is removed from the main body frame 100 and attached to the main body frame 100 of another image forming apparatus 1, the control unit 40 of the other image forming apparatus 1 can read the latest second number of prints X2 from the second development memory 23. Therefore, the control unit 40 of the other image forming apparatus 1 can calculate an appropriate second voltage value V2 based on the latest second number of prints X2.

[0062] <3. Modifications> Although one embodiment of the present disclosure has been described above, the present disclosure is not limited to the above embodiment.

[0063] <3-1. First modified example> Fig. 8 is a diagram showing information stored in the first development memory 13 of the first modified example. As shown in Fig. 8, the first development memory 13 may store multiple types of first change rate A1 and first intercept B1 according to the printing speed. Specifically, it is preferable to set the first change rate A1 and first intercept B1 so that the faster the printing speed, the higher the first voltage value V1.

[0064] In this case, the control unit 40 may read the first change rate A1 and first intercept B1 corresponding to the printing speed specified by the print job from the first development memory 13. Then, the control unit 40 may calculate the first voltage value V1 corresponding to the first number of prints X1 based on the first change rate A1 and first intercept B1 corresponding to the printing speed. This allows the first voltage value V1 supplied to the first developing roller shaft 122 to be further optimized according to the printing speed. As a result, changes in print density can be further suppressed.

[0065] Similarly, the second development memory 23 may store a plurality of second change rates A2 and second intercepts B2 corresponding to different printing speeds. The control unit 40 may then calculate the second voltage value V2 corresponding to the second number of prints X2 based on the second change rates A2 and second intercepts B2 corresponding to the printing speeds.

[0066] <3-2. Second modified example> 9 is a flowchart showing the flow of printing processing by the image forming apparatus 1 of the second modified example. In the embodiment described above, the control unit 40 writes the latest first number of prints X1 to the first developing memory 13 in step S5. In contrast, in the example of FIG. 9, the control unit 40 writes the latest first voltage value V1 to the first developing memory 13 in step S5.

[0067] In this way, when printing is performed with the first developer cartridge 10 attached to the main body frame 100, the control unit 40 may write the first voltage value V1 supplied to the first developer roller shaft 122 to the first development memory 13. In this way, the latest first voltage value V1 is stored in the first development memory 13. Therefore, even if a first developer cartridge 10 that is being used is removed from the main body frame 100 and attached to the main body frame 100 of another image forming apparatus 1, the control unit 40 of the other image forming apparatus 1 can read the latest first voltage value V1 from the first development memory 13 and recognize the latest first number of printed sheets X1 based on the first voltage value V1. Therefore, the control unit 40 of the other image forming apparatus 1 can calculate an appropriate first voltage value V1 based on the latest first number of printed sheets X1.

[0068] Similarly, when printing is performed with the second developing cartridge 20 attached to the main body frame 100, the control unit 40 may write the second voltage value V2 supplied to the second developing roller shaft 222 to the second developing memory 23. In this way, the latest second voltage value V2 may be stored in the second developing memory 23.

[0069] <3-3.Third modified example> FIG. 10 is a diagram showing information stored in the first developing memory 13 of the third modified example. In the above-described embodiment, the first developing memory 13 stores the first change rate A1 and the first intercept B1. In contrast, in the example of FIG. 10, the first developing memory 13 stores the specifications C1 of the first developing cartridge 10 instead of the first change rate A1 and the first intercept B1. The specifications C1 are, for example, at least one of the manufacturer of the first developing roller 12, the number of times the first developing roller 12 has been recycled, and the amount of toner contained inside the first developing cartridge 10.

[0070] Fig. 11 is a diagram showing information stored in the main body memory 42 of the third modified example. In the example of Fig. 11, the main body memory 42 stores a table T. The table T is information indicating the correspondence between the specification C1 of the first developing cartridge 10 and the first change rate A1 and the first intercept B1.

[0071] Fig. 12 is a diagram showing an example of Table T. Table T in Fig. 12 specifies the values ​​of the first rate of change A1 and the first intercept B1 for each combination of the manufacturer of the first developing roller 12 and the amount of toner contained inside the first developing cartridge 10.

[0072] When the first developer cartridge 10 is attached to the main body frame 100, the control unit 40 reads out the specification C1 from the first developer memory 13. The control unit 40 also reads out a table T from the main body memory 42. The control unit 40 then refers to the table T to calculate a first change rate A1 and a first intercept B1 corresponding to the specification C1 read out from the first developer memory 13. Thereafter, the control unit 40 calculates a first voltage value V1 based on the first change rate A1, the first intercept B1, and the first number of printed sheets X1, as in the above embodiment.

[0073] As described above, in the third modified example, the first developing memory 13 stores the specifications C1 of the first developing cartridge 10, rather than storing the first voltage value V1, the first change rate A1, and the first intercept B1. The control unit 40 then calculates the first change rate A1 and the first intercept B1 based on the specifications C1 read from the first developing memory 13. The control unit 40 then calculates the first voltage value V1 corresponding to the first number of prints X1 based on the first change rate A1 and the first intercept B1. This allows the first voltage value V1 to be calculated while reducing the amount of information stored in the first developing memory 13.

[0074] Similarly, the specifications of the second developer cartridge 20 may be stored in the second developer memory 23 of the second developer cartridge 20. In this case, the control unit 40 reads the specifications from the second developer memory 23 and calculates the second change rate A2 and the second intercept B2 based on the read specifications. The control unit 40 then calculates the second voltage value V2 corresponding to the second number of prints X2 based on the second change rate A2 and the second intercept B2. This makes it possible to calculate the second voltage value V2 while reducing the amount of information stored in the second developer memory 23. <3-4. Other variations>

[0075] In the above embodiment, the first developer cartridge 10 was attached to the main body frame 100 when attached to the drum cartridge 30. However, the first developer cartridge 10 may be attached directly to the main body frame 100 without being attached to the drum cartridge 30. Also, in the above embodiment, the second developer cartridge 20 was attached to the main body frame 100 when attached to the drum cartridge 30. However, the second developer cartridge 20 may be attached directly to the main body frame 100 without being attached to the drum cartridge 30.

[0076] In the above embodiment, two types of developer cartridges, the first developer cartridge 10 and the second developer cartridge 20, can be attached to the main body frame 100. However, the number of types of developer cartridges that can be attached to the main body frame 100 may be three or more.

[0077] In the above embodiment, the first developing memory 13 stores the first number of prints X1, but this is not limiting. For example, the main body memory 42 may store the first number of prints X1.

[0078] In the above embodiment, the second development memory 23 stores the second number of prints X2, but this is not limiting. For example, the main body memory 42 may store the second number of prints X2.

[0079] The details of the configuration and processing of the image forming apparatus may be appropriately modified without departing from the spirit of the present disclosure. Furthermore, the elements appearing in the above-described embodiments and modifications may be appropriately combined without causing any contradiction. [Explanation of symbols]

[0080] 1: Image forming device 10: First developing cartridge 12: First developing roller 13: First development memory 20: Second developing cartridge 22: Second developing roller 23: Second development memory 30: Drum cartridge 31: Photosensitive drum 40: Control section 100: Main frame 101: Electrode A1: First rate of change A2: Second rate of change B1: 1st section B2: 2nd section C1: Specifications T: Table V1: First voltage value V2: Second voltage value Vmax: Maximum voltage value Vmin: Minimum voltage value X1: First print quantity X2: Second print quantity

Claims

1. An image forming apparatus having a main body frame to which either a first developing cartridge or a second developing cartridge can be attached, The first developing cartridge is a first developing roller; a first development memory that stores a first rate of change and a first intercept that indicate a change in a first voltage value supplied to the first development roller according to the number of printed sheets; and The second developing cartridge is A second developing roller; a second development memory that stores a second rate of change and a second intercept that indicate a change in the second voltage value supplied to the second development roller according to the number of printed sheets, the second rate of change being different from the first rate of change and the second intercept being different from the first intercept; and the image forming apparatus, a control unit that is electrically connected to the first developing roller and the first developing memory when the first developing cartridge is attached to the main body frame, and that is electrically connected to the second developing roller and the second developing memory when the second developing cartridge is attached to the main body frame; Equipped with The control unit When the first developing cartridge is attached to the main body frame, reading out the first rate of change and the first intercept from the first development memory; calculating the first voltage value based on the first rate of change, the first intercept, and the number of printed sheets; supplying a voltage of the first voltage value to the first developing roller; When the second developing cartridge is attached to the main body frame, reading out the second change rate and the second intercept from the second development memory; calculating the second voltage value based on the second rate of change, the second intercept, and the number of printed sheets; a voltage of the second voltage value is supplied to the second developing roller; An image forming apparatus comprising:

2. 2. The image forming apparatus according to claim 1, The control unit a main memory for storing a maximum voltage value that is an upper limit value of the first voltage value and the second voltage value; and The control unit supplying a voltage of the maximum voltage value to the first developing roller when the first voltage value calculated based on the first rate of change, the first intercept, and the number of printed sheets is greater than the maximum voltage value; When the second voltage value calculated based on the second rate of change, the second intercept, and the number of printed sheets is greater than the maximum voltage value, a voltage of the maximum voltage value is supplied to the second developing roller. An image forming apparatus comprising:

3. 2. The image forming apparatus according to claim 1, The control unit a main memory for storing a minimum voltage value that is a lower limit of the first voltage value and the second voltage value; and The control unit supplying a voltage of the minimum voltage value to the first developing roller when the first voltage value calculated based on the first rate of change, the first intercept, and the number of printed sheets is smaller than the minimum voltage value; When the second voltage value calculated based on the second rate of change, the second intercept, and the number of printed sheets is smaller than the minimum voltage value, a voltage of the minimum voltage value is supplied to the second developing roller. An image forming apparatus comprising:

4. 4. The image forming apparatus according to claim 1, The image forming apparatus is characterized in that the first developing roller and the second developing roller are made by different manufacturers.

5. 4. The image forming apparatus according to claim 1, 10. An image forming apparatus, wherein the first developing roller and the second developing roller have different recycling counts.

6. 4. The image forming apparatus according to claim 1, The image forming apparatus is characterized in that the first developing cartridge and the second developing cartridge have different amounts of toner stored therein.

7. 4. The image forming apparatus according to claim 1, the first development memory stores a plurality of types of the first change rate and the first intercept according to the printing speed; The image forming apparatus, wherein the control unit calculates the first voltage value based on the first rate of change and the first intercept corresponding to a printing speed specified by a job.

8. 2. The image forming apparatus according to claim 1, the control unit has a main body memory for storing the number of prints, The image forming apparatus is characterized in that the control unit updates the number of prints stored in the main body memory when printing is performed.

9. 4. The image forming apparatus according to claim 1, the first developing memory stores the number of prints made by the first developing cartridge; the second developing memory stores the number of prints made by the second developing cartridge; The control unit When printing is performed with the first developing cartridge attached to the main body frame, the number of printed sheets stored in the first developing memory is updated; When printing is performed with the second developing cartridge attached to the main body frame, the number of prints stored in the second developing memory is updated. An image forming apparatus comprising:

10. 4. The image forming apparatus according to claim 1, the first development memory stores the first voltage value; the second development memory stores the second voltage value; The control unit when printing is performed with the first developing cartridge attached to the main body frame, the first voltage value supplied to the first developing roller is written into the first developing memory; When printing is performed with the second developing cartridge attached to the main body frame, the second voltage value supplied to the second developing roller is written to the second developing memory. An image forming apparatus comprising:

11. An image forming apparatus having a main body frame to which either a first developing cartridge or a second developing cartridge can be attached, The first developing cartridge is a first developing roller; a first developing memory that stores the specifications of the first developing cartridge; and The second developing cartridge is A second developing roller; a second developing memory that stores the specifications of the second developing cartridge; and a control unit that is electrically connected to the first developing roller and the first developing memory when the first developing cartridge is attached to the main body frame, and that is electrically connected to the second developing roller and the second developing memory when the second developing cartridge is attached to the main body frame; Equipped with The control unit When the first developing cartridge is attached to the main body frame, reading the specifications from the first development memory; calculating a first rate of change and a first intercept that indicate a change in a first voltage value supplied to the first developing roller according to the number of printed sheets, based on the specifications read from the first developing memory; calculating the first voltage value based on the first rate of change, the first intercept, and the number of printed sheets; supplying a voltage of the first voltage value to the first developing roller; When the second developing cartridge is attached to the main body frame, reading the specifications from the second development memory; calculating a second rate of change and a second intercept, which indicate a change in the second voltage value supplied to the second developing roller according to the number of printed sheets, based on the specifications read from the second developing memory; calculating the second voltage value based on the second rate of change, the second intercept, and the number of printed sheets; a voltage of the second voltage value is supplied to the second developing roller; An image forming apparatus comprising:

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