Image forming apparatus

Abstract

To provide a technique that can prevent printing quality from changing according to the type of a drum unit and the type of a transfer unit.SOLUTION: A control unit 8 of an image forming apparatus 1 reads out drum information indicating the type of a drum unit 4 from a drum memory 42. The control unit 8 reads out transfer information indicating the type of a transfer unit 5 from a transfer memory 54. The control unit 8 determines an output value of current or voltage to be supplied to the transfer roller 53 on the basis of the drum information and the transfer information. In this way, the output value of the current or the voltage supplied to the transfer roller 53 can be changed according to the combination of the type of the drum unit 4 and the type of the transfer unit 5. This can prevent printing quality from changing according to the type of the drum unit 4 and the type of the transfer unit 5.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Electrophotographic image forming apparatuses such as laser printers and LED printers are well known. The image forming apparatuses include a drum unit and a transfer unit. The drum unit includes a photosensitive drum. The transfer unit includes a transfer roller and a belt.

[0003] When printing is performed in the image forming apparatus 1, a current is supplied to the transfer roller. This 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 electrostatic force caused by the voltage on the transfer roller transfers toner from the photosensitive drum to the printing paper.

[0004] A conventional image forming apparatus having a drum unit and a transfer unit is described in, for example, Patent Document 1. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-25449 Summary of the Invention [Problem to be solved by the invention]

[0006] However, if the type of drum unit or transfer unit changes, the results of toner transfer from the photosensitive drum to the print paper will change even if the current value supplied to the transfer roller is the same.In order to stabilize print quality, it is necessary to suppress changes in the results of toner transfer depending on the type of drum unit and transfer unit.

[0007] An object of the present disclosure is to provide a technology that can suppress changes in print quality depending on the type of drum unit and the type of transfer unit. [Means for solving the problem]

[0008] The first disclosure of the present application comprises a frame, a drum unit replaceable with respect to the frame, the drum unit having a photosensitive drum and a drum memory storing drum information indicating the type of the drum unit, a transfer unit replaceable with respect to the frame, the transfer unit having a transfer roller and a transfer memory storing transfer information indicating the type of the transfer unit, and a control unit electrically connected to the drum memory, the transfer roller, and the transfer memory when the drum unit and the transfer unit are attached to the frame, wherein the control unit executes a drum information reading process that reads the drum information from the drum memory, a transfer information reading process that reads the transfer information from the transfer memory, and an output value determination process that determines an output value of current or voltage to be supplied to the transfer roller based on the drum information and the transfer information.

[0009] A second disclosure of the present application is the image forming apparatus of the first disclosure, characterized in that the control unit has a main body memory that stores multiple types of tables showing the relationship between printing conditions and the output value, and in the output value determination process, the control unit selects one of the multiple types of tables based on the drum information and the transfer information, and determines the output value according to the printing conditions in the selected table.

[0010] A third disclosure of the present application is the image forming apparatus of the second disclosure, characterized in that the printing conditions include at least one of temperature, humidity, type of printing paper, width of printing paper, and printing speed.

[0011] A fourth disclosure of the present application is an image forming apparatus according to the second or third disclosure, further comprising a developing roller, wherein the control unit further executes a correction process to correct the output value shown in the table based on toner information indicating the amount of toner used by the developing roller.

[0012] The fifth disclosure of the present application is the image forming apparatus of the fourth disclosure, characterized in that the toner information is any one of the cumulative number of rotations of the developing roller, the cumulative number of prints using the developing roller, and the cumulative dot count using the developing roller.

[0013] The sixth disclosure of the present application is an image forming apparatus according to the fourth or fifth disclosure, characterized in that the amount of correction of the output value in the correction process increases as the usage amount indicated by the toner information increases.

[0014] The seventh disclosure of the present application is an image forming apparatus according to any one of the fourth to sixth disclosures, comprising a toner cartridge that is replaceable with respect to the frame, the toner cartridge having the developing roller and a toner memory that stores the toner information, and when the toner cartridge is attached to the frame, the control unit is electrically connected to the toner memory, the control unit further executes a toner information reading process that reads the toner information from the toner memory, and in the correction process, the control unit corrects the output value based on the toner information read in the toner information reading process.

[0015] An eighth disclosure of the present application is the image forming apparatus of any one of the first to seventh disclosures, characterized in that the transfer information indicates the type of the transfer roller.

[0016] A ninth disclosure of the present application is the image forming apparatus of the eighth disclosure, wherein the transfer information indicates a manufacturer of the transfer roller.

[0017] A tenth disclosure of the present application is the image forming apparatus according to any one of the first to ninth disclosures, wherein the drum information indicates the type of the photosensitive drum.

[0018] An eleventh disclosure of the present application is the image forming apparatus of the tenth disclosure, wherein the drum information indicates a manufacturer of the photosensitive drum.

[0019] The twelfth disclosure of the present application is an image forming apparatus according to any one of the first to eleventh disclosures, characterized in that the control unit further executes a printing process that performs printing while supplying the current or voltage of the output value determined in the output value determination process to the transfer roller.

[0020] The 13th disclosure of the present application is an image forming apparatus according to any one of the first to third disclosures, wherein the frame has an opening through which the drum unit or the transfer unit passes when the drum unit or the transfer unit is attached to the frame, and a cover that opens and closes the opening, and the control unit executes the drum information reading process, the transfer information reading process, and the output value determination process when it detects that the power of the image forming apparatus has been switched from OFF to ON or that the cover has moved from an open position to a closed position. [Effects of the Invention]

[0021] According to the first to thirteenth disclosures of the present application, the output value of the current or voltage supplied to the transfer roller can be changed depending on the combination of the type of drum unit and the type of transfer unit, thereby preventing print quality from varying depending on the type of drum unit and the type of transfer unit.

[0022] Furthermore, according to the second disclosure of the present application, the output value of the current or voltage supplied to the transfer roller can be changed depending on the printing conditions.

[0023] According to the fourth disclosure of the present application, the output value of the current supplied to the transfer roller is corrected based on the amount of toner used by the developing roller, thereby preventing the amount of toner transferred from the photosensitive drum to the printing paper from changing depending on the amount of toner used by the developing roller. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a schematic diagram of an image forming apparatus. [Figure 2] 10 is a flowchart showing a processing flow of the image forming apparatus. [Figure 3] 10 is a flowchart showing the flow of a latch process. [Figure 4] FIG. 10 is a diagram showing an example of a table. [Figure 5] 10 is a flowchart showing the flow of an output value determination process. [Figure 6] FIG. 10 is a diagram showing an example of reference information. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, preferred embodiments of the present disclosure will be described with reference to the drawings.

[0026] <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 frame 2, four toner cartridges 3, a drum unit 4, a transfer unit 5, and a control unit 8.

[0027] The frame 2 has an opening 21 and a cover 22. The cover 22 is movable between an open position where the opening 21 is open and a closed position where the opening 21 is closed. The image forming apparatus 1 has a cover sensor 23 that detects that the cover 22 has moved from the open position to the closed position. When the cover sensor 23 detects that the cover 22 has rotated from the open position to the closed position, it transmits a detection signal to the control unit 8.

[0028] The four toner cartridges 3 are detachable from the drum unit 4. Furthermore, the drum unit 4 with the four toner cartridges 3 attached thereto is detachable from the frame 2. The drum unit 4 with the four toner cartridges 3 attached thereto is attached to the frame 2 through an opening 21. In other words, the four toner cartridges 3 and the drum unit 4 are all replaceable with respect to the frame 2.

[0029] Each of the four toner cartridges 3 has a developing roller 31. The drum unit 4 has four photosensitive drums 41. When a toner cartridge 3 is attached to the drum unit 4, the developing roller 31 comes into contact with the photosensitive drum 41. The four toner cartridges 3 contain toner of different colors (for example, cyan, magenta, yellow, and black).

[0030] 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 frame 2. In other words, the transfer unit 5 is replaceable with respect to the frame 2. The transfer unit 5 is attached to the frame 2 through an opening 21.

[0031] 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.

[0032] Transfer roller 53 is a roller for transferring toner from photosensitive drum 41 to printing paper. When transfer unit 5 is mounted on frame 2 and drum unit 4, on which four toner cartridges 3 are mounted, is also mounted on frame 2, a portion of belt 52 is positioned between photosensitive drum 41 and transfer roller 53. Specifically, a portion of belt 52 is sandwiched between photosensitive drum 41 and transfer roller 53. Furthermore, when transfer unit 5 is mounted on frame 2, the four transfer rollers 53 are electrically connected to control unit 8.

[0033] The control unit 8 is located within the frame 2. As shown in FIG. 1, 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.

[0034] The image forming apparatus 1 also has a thermometer 83 and a hygrometer 84. The thermometer 83 measures the temperature inside the frame 2. The thermometer 83 also inputs the measured temperature value to the control unit 8. The hygrometer 84 measures the humidity inside the frame 2. The hygrometer 84 also inputs the measured humidity value to the control unit 8.

[0035] When the image forming apparatus 1 performs a printing process, the toner contained in the toner cartridge 3 is supplied to the photosensitive drum 41 via the developing roller 31. The toner moves from the developing 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. As a result, a toner image is formed on the outer circumferential surface of the photosensitive drum 41.

[0036] The printing paper moves together with the belt 52 and is transported between the photosensitive drum 41 and the transfer roller 53. At this time, the control unit 8 supplies a current to the transfer roller 53. As a result, a voltage corresponding to the current is applied to the transfer roller 53. The toner image formed on the outer peripheral surface of the photosensitive drum 41 is transferred from the outer peripheral 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. Toner memory> As shown in FIG. 1, the toner cartridge 3 has a toner memory 32. The toner memory 32 is a storage medium from which information can be read and written. When the drum unit 4 with the four toner cartridges 3 installed is mounted on the frame 2, the toner memory 32 is electrically connected to the control unit 8. This allows the control unit 8 to read information from the toner memory 32 and write information to the transfer memory 54.

[0038] Toner information is stored in the toner memory 32. The toner information is information indicating the amount of toner used by the developing roller 31. The toner information includes, for example, at least one of the cumulative number of rotations, the cumulative number of printed pages, and the cumulative dot count. The cumulative number of rotations indicates the number of times the developing roller 31 has rotated after use of the toner cartridge 3 in the image forming device 1 began. The cumulative number of printed pages indicates the number of pages printed using the developing roller 31 after use of the toner cartridge 3 in the image forming device 1 began. The cumulative dot count indicates the number of dots printed using the developing roller 31 after use of the toner cartridge 3 in the image forming device 1 began.

[0039] <3. About Drum Memory> As shown in FIG. 1, the drum unit 4 has a drum memory 42. The drum memory 42 is a storage medium from which information can be read and written. When the drum unit 4 is attached to the frame 2, the drum memory 42 is electrically connected to the control unit 8. This allows the control unit 8 to read information from and write information to the drum memory 42.

[0040] Drum information is stored in the drum memory 42. The drum information is information indicating the type of drum unit 4. For example, the drum information is information indicating the type of photosensitive drum 41. More specifically, the drum information is information indicating the manufacturer of the photosensitive drum 41. The drum information may also be information indicating the number of times the photosensitive drum 41 has been recycled.

[0041] <4. About transcription memory> As shown in FIG. 1, 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 frame 2, the transfer memory 54 is electrically connected to the control unit 8. This allows the control unit 8 to read information from the transfer memory 54 and write information to the transfer memory 54.

[0042] Transfer information is stored in the transfer memory 54. The transfer information is information indicating the type of transfer unit 5. For example, the transfer information is information indicating the type of transfer roller 53. More specifically, the transfer information is information indicating the manufacturer of the transfer roller 53. The transfer information may also be information indicating the number of times the transfer roller 53 has been recycled.

[0043] <5. Processing of the control section> Next, a description will be given of the processing executed by the control unit 8 in the image forming apparatus 1. Fig. 2 is a flowchart showing the processing flow of the image forming apparatus 1. It is assumed that, at the start of the processing in Fig. 2, the transfer unit 5 is attached to the frame 2, and the drum unit 4 with four toner cartridges 3 attached thereto is attached to the frame 2.

[0044] 2, the control unit 8 first detects that the power of the image forming apparatus 1 has been switched from OFF to ON or that the cover 22 has moved from the open position to the closed position (step S1). For example, when the supply of power 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, the control unit 8 determines that the cover 22 has moved from the open position to the closed position.

[0045] When the control unit 8 detects that the power has been switched from OFF to ON or that the cover 22 has moved from the open position to the closed position (step S1: yes), the control unit 8 then executes a latch process (step S2). The latch process is a process in which the control unit 8 reads information from the toner memory 32, the drum memory 42, and the transfer memory 54.

[0046] 3 is a flowchart showing the flow of the latch process. As shown in FIG. 3, the control unit 8 executes the steps of reading transfer information from the transfer memory 54 (step S21: transfer information reading process), reading drum information from the drum memory 42 (step S22: drum information reading process), and reading toner information from the toner memory 32 (step S23: toner information reading process). Then, the control unit 8 writes the read transfer information, drum information, and toner information to the main body memory 82.

[0047] Note that steps S21 to S23 may be executed in any order different from that shown in FIG.

[0048] Returning to Fig. 2, when the latching process is completed, the control unit 8 determines the output value V of the current to be supplied to the transfer roller 53 (step S3: output value determination process). In the output value determination process, the control unit 8 determines the output value V of the current to be supplied to the transfer roller 53 based on the drum information and the transfer information.

[0049] Fig. 4 is a diagram showing an example of table T used in the output value determination process. As shown in Fig. 4, multiple types of table T are stored in main body memory 82. Table T is information indicating the relationship between printing conditions and output value V of the current to be supplied to transfer roller 53. The printing conditions include at least one of the temperature measured by thermometer 83, humidity measured by hygrometer 84, type of printing paper, width of printing paper, and printing speed.

[0050] 5 is a flowchart showing the flow of the output value determination process. As shown in FIG. 5, the control unit 8 first selects one table T from among a plurality of types of tables T (step S31: table selection process).

[0051] The main body memory 82 pre-stores reference information R that indicates the correspondence between combinations of drum information and transfer information and the corresponding tables T. Fig. 6 is a diagram showing an example of the reference information R. As shown in Fig. 6, the reference information R specifies one table T for each combination of transfer information and drum information.

[0052] For example, if the transfer information read from the transfer memory 54 in step S21 is "first transfer information" and the drum information read from the drum memory 42 in step S22 is "first drum information," the control unit 8 selects "first table" as table T by referring to the reference information R. In this way, the control unit 8 selects one of the multiple types of tables T based on the drum information and the transfer information.

[0053] Next, the control unit 8 corrects the output value V shown in the selected table T based on the toner information (step S32: table correction process). In this embodiment, toner that is positively charged by friction is used. However, the toner becomes less likely to be charged with use. Therefore, the control unit 8 corrects the output value V of the table T so that the output value V supplied to the transfer roller 53 increases as the amount of use of the developing roller 31 indicated by the toner information increases.

[0054] For example, if the usage amount of the developing roller 31 indicated by the toner information read from the toner memory 32 in step S23 is less than a first threshold, the control unit 8 does not correct the output value V indicated in table T. Furthermore, if the usage amount of the developing roller 31 indicated by the toner information read from the toner memory 32 in step S23 is equal to or greater than the first threshold and less than a second threshold that is greater than the first threshold, the control unit 8 adds a first correction amount to the output value V indicated in table T. Furthermore, if the usage amount of the developing roller 31 indicated by the toner information read from the toner memory 32 in step S23 is equal to or greater than a second threshold, the control unit 8 adds a second correction amount that is greater than the first correction amount to the output value V indicated in table T.

[0055] Alternatively, the control unit 8 may calculate the correction amount by multiplying the usage amount of the developing roller 31 indicated by the toner information read out from the toner memory 32 in step S23 by a predetermined coefficient. Then, the control unit 8 may add the calculated correction amount to the output value V indicated in the table T.

[0056] Next, the control unit 8 determines the output value V of the current to be supplied to the transfer roller 53 based on the corrected table T (step S33). The control unit 8 calculates the printing conditions based on any one or a combination of the temperature, humidity, type of printing paper, width of printing paper, and printing speed. The control unit 8 then references the corrected table T to determine the output value V corresponding to the calculated printing conditions and the toner color.

[0057] Thereafter, when a print job is input to the control unit 8, the control unit 8 executes the print process (step S4: print process). At that time, the control unit 8 supplies a current of the output value V determined in step S33 to the transfer roller 53. This generates an electrostatic force between the photosensitive drum 41 and the transfer roller 53. As a result, the toner image is transferred from the photosensitive drum 41 to the printing paper.

[0058] As described above, the image forming apparatus 1 determines the output value V of the current to be supplied to the transfer roller 53 based on the drum information and the transfer information. Therefore, the output value V of the current to be supplied to the transfer roller 53 can be changed depending on the combination of the type of drum unit 4 and the type of transfer unit 5. This makes it possible to prevent changes in print quality depending on the type of drum unit 4 and the type of transfer unit 5.

[0059] Furthermore, the image forming apparatus 1 of this embodiment determines the output value V to be supplied to the transfer roller 53 taking into consideration not only the drum information and transfer information but also the printing conditions. Therefore, the output value V of the current supplied to the transfer roller 53 can be changed according to the printing conditions. For example, the higher the temperature measured by the thermometer 83, the more the output value V can be increased. Also, the higher the humidity measured by the hygrometer 84, the more the output value V can be increased. Also, the faster the printing speed, the more the output value V can be increased. This allows the toner image to be transferred more satisfactorily from the photosensitive drum 41 to the printing paper.

[0060] Furthermore, the image forming apparatus 1 of this embodiment corrects the output value V of the current supplied to the transfer roller 53 based on the usage amount of the developing roller 31 indicated by the toner information. Specifically, the control unit 8 increases the correction amount of the output value V as the usage amount of the developing roller 31 indicated by the toner information increases. This makes it possible to prevent a decrease in the amount of toner transferred from the photosensitive drum 41 to the printing paper in accordance with a decrease in the charge amount of the toner.

[0061] <6. Variations> Although one embodiment has been described above, the present disclosure is not limited to the above embodiment.

[0062] In the above embodiment, the control unit 8 controls the current supplied to the transfer roller 53. However, the control unit 8 may also control the voltage supplied to the transfer roller 53. In this case, the control unit 8 determines the output value V of the voltage to be supplied to the transfer roller 53 based on the drum information and the transfer information. In this case, the output value V of the voltage to be supplied to the transfer roller 53 may be specified in the table T for each printing condition.

[0063] In the above embodiment, the number of toner cartridges 3 mounted on the drum unit 4 is four. However, the number of toner cartridges 3 mounted on the drum unit 4 may be one to three, or five or more. The number of transfer rollers 53 provided in the transfer unit 5 may also be one to three, or five or more.

[0064] 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]

[0065] 1: Image forming device 2: Frame 3: Toner cartridge 4: Drum unit 5: Transcription unit 8: Control section 31: Developing roller 32: Toner memory 41: Photosensitive drum 42: Drum memory 52: Belt 53: Transfer roller 54: Transfer Memory T: Table V: Output value

Claims

1. The frame and a drum unit replaceable with respect to the frame, A photosensitive drum; a drum memory that stores drum information indicating the type of the drum unit; a drum unit having A transfer unit that is replaceable with respect to the frame, A transfer roller; a transfer memory that stores transfer information indicating the type of the transfer unit; a transcription unit having a control unit electrically connected to the drum memory, the transfer roller, and the transfer memory when the drum unit and the transfer unit are mounted on the frame; Equipped with The control unit a drum information reading process for reading the drum information from the drum memory; a transfer information reading process for reading the transfer information from the transfer memory; an output value determination process for determining an output value of a current or a voltage to be supplied to the transfer roller based on the drum information and the transfer information; An image forming apparatus comprising:

2. 2. The image forming apparatus according to claim 1, The control unit A main memory that stores a plurality of types of tables showing the relationship between printing conditions and the output values. and an image forming apparatus characterized in that, in the output value determination process, the control unit selects one of the plurality of types of tables based on the drum information and the transfer information, and determines the output value according to the printing conditions in the selected table.

3. 3. The image forming apparatus according to claim 2, The image forming apparatus is characterized in that the printing conditions include at least one of temperature, humidity, type of printing paper, width of printing paper, and printing speed.

4. 4. The image forming apparatus according to claim 2, wherein: Developing roller Furthermore, The control unit a correction process for correcting the output value shown in the table based on toner information indicating the amount of toner used by the developing roller; The image forming apparatus further comprises:

5. 5. The image forming apparatus according to claim 4, The toner information the cumulative number of rotations of the developing roller; The cumulative number of prints using the developing roller, and Cumulative dot count using the developing roller 1. An image forming apparatus, comprising:

6. 5. The image forming apparatus according to claim 4, an amount of correction of the output value in the correction process increasing as the amount of use indicated by the toner information increases;

7. 5. The image forming apparatus according to claim 4, a toner cartridge replaceable with respect to the frame, the developing roller; a toner memory that stores the toner information; Toner cartridge having Equipped with When the toner cartridge is attached to the frame, the control unit is electrically connected to the toner memory, The control unit A toner information reading process for reading the toner information from the toner memory. Further execute The image forming apparatus, wherein the control unit corrects the output value in the correction process based on the toner information read in the toner information reading process.

8. 4. The image forming apparatus according to claim 1, 10. An image forming apparatus, wherein the transfer information indicates a type of the transfer roller.

9. 9. The image forming apparatus according to claim 8, 10. An image forming apparatus, wherein the transfer information indicates a manufacturer of the transfer roller.

10. 4. The image forming apparatus according to claim 1, 2. An image forming apparatus, wherein the drum information indicates a type of the photosensitive drum.

11. 11. The image forming apparatus according to claim 10, 10. An image forming apparatus, wherein the drum information indicates a manufacturer of the photosensitive drum.

12. 4. The image forming apparatus according to claim 1, The control unit A printing process in which printing is performed while supplying the current or voltage of the output value determined in the output value determination process to the transfer roller. The image forming apparatus further comprises:

13. 4. The image forming apparatus according to claim 1, The frame is an opening through which the drum unit or the transfer unit passes when the drum unit or the transfer unit is attached to the frame; a cover that opens and closes the opening; and The image forming apparatus is characterized in that the control unit executes the drum information reading process, the transfer information reading process, and the output value determination process when it detects that the power of the image forming apparatus has been switched from OFF to ON or that the cover has moved from an open position to a closed position.

Images