Method for recycling

Abstract

To provide a technique of determining the state of a cleaning roller without disassembling a drum unit.SOLUTION: A measuring instrument 90 acquires a measurement value V reflecting the nip pressure between a photosensitive drum 30 and a cleaning roller 40, with the photosensitive drum 30 and the cleaning roller 40 being assembled to a drum frame. Then, whether the measurement value V is equal to or greater than a first threshold value V1 is determined. The state of the cleaning roller 40 can be thus determined without disassembling the drum unit.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present disclosure relates to recycling methods. [Background technology]

[0002] Electrophotographic image forming devices such as laser printers and LED printers are well known. These image forming devices have a drum unit that is detachable from a main body frame. The drum unit has a photosensitive drum and a cleaning roller that cleans the photosensitive drum. The cleaning roller removes toner and paper dust from the outer circumferential surface of the photosensitive drum.

[0003] A conventional drum unit having a cleaning roller is described in, for example, Patent Document 1. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-182009 Summary of the Invention [Problem to be solved by the invention]

[0005] Used drum units are sometimes recycled to make effective use of resources. In such cases, it is necessary to determine whether the cleaning roller can be reused. However, in the past, determining whether the cleaning roller can be reused required disassembling the drum unit and inspecting the cleaning roller. This resulted in a labor-intensive process.

[0006] An object of the present disclosure is to provide a technique that can determine the state of a cleaning roller without disassembling the drum unit. [Means for solving the problem]

[0007] The first disclosure of the present application is a method for recycling a used drum unit that includes a drum frame, a photosensitive drum, and a cleaning roller that contacts the photosensitive drum, and is characterized by having a measurement step of obtaining a measurement value that reflects the nip pressure between the photosensitive drum and the cleaning roller using a measuring instrument while the photosensitive drum and the cleaning roller are assembled to the drum frame, and a determination step of determining whether the measurement value is equal to or greater than a first threshold value.

[0008] The second disclosure of the present application is the recycling method of the first disclosure, characterized in that the measuring instrument includes a pressure-sensitive element, and the measuring process includes a process of inserting the pressure-sensitive element between the photosensitive drum and the cleaning roller, and a process of acquiring the measurement value output from the pressure-sensitive element as the measurement value.

[0009] A third disclosure of the present application is the recycling method of the first or second disclosure, wherein the measuring device includes a force gauge and a sheet connected to a measurement axis of the force gauge, and the measuring step includes inserting the sheet between the photosensitive drum and the cleaning roller, and measuring, as the measurement value, the tensile force when pulling the sheet out from between the photosensitive drum and the cleaning roller while the rotation of the photosensitive drum and the cleaning roller is stopped, using the force gauge.

[0010] The fourth disclosure of the present application is a method for recycling a used drum unit comprising a drum frame, a photosensitive drum, a cleaning roller in contact with the photosensitive drum, and a cleaning shaft in contact with the cleaning roller, characterized by comprising: a measurement step of obtaining a measurement value reflecting the nip pressure between the cleaning roller and the cleaning shaft using a measuring instrument while the cleaning roller and the cleaning shaft are assembled to the drum frame; and a determination step of determining whether the measurement value is equal to or greater than a first threshold value.

[0011] The fifth disclosure of the present application is the recycling method of the fourth disclosure, characterized in that the measuring instrument includes a pressure-sensitive element, and the measuring process includes a process of inserting the pressure-sensitive element between the cleaning roller and the cleaning shaft, and a process of acquiring the measurement value output from the pressure-sensitive element as the measurement value.

[0012] A sixth disclosure of the present application is the recycling method of the fourth or fifth disclosure, wherein the measuring device includes a force gauge and a sheet connected to a measurement axis of the force gauge, and the measuring step includes inserting the sheet between the cleaning roller and the cleaning shaft, and measuring, as the measurement value, the tensile force when pulling the sheet out from between the cleaning roller and the cleaning shaft while stopping the rotation of the cleaning roller and the cleaning shaft, using the force gauge.

[0013] The seventh disclosure of the present application is a recycling method according to any one of the first to sixth disclosures, characterized in that in the measurement process, the measurement values are obtained at multiple positions in a first direction parallel to the rotation axis of the cleaning roller, and in the determination process, it is determined whether all of the multiple measurement values are greater than or equal to the first threshold value.

[0014] The eighth disclosure of the present application is the recycling method of the seventh disclosure, characterized in that the determination step determines whether the difference between the maximum and minimum values of the multiple measurement values is less than or equal to a second threshold value.

[0015] A ninth disclosure of the present application is a recycling method according to any one of the first to eighth disclosures, characterized in that, in the determination process, if the measurement value is determined to be equal to or greater than the first threshold value, it is determined that the cleaning roller can be recycled, and if the measurement value is determined to be less than the first threshold value, it is determined that the cleaning roller cannot be recycled.

[0016] A tenth disclosure of the present application is the recycling method of the ninth disclosure, characterized in that it further comprises a replacement step of replacing the cleaning roller when it is determined that the cleaning roller cannot be recycled.

[0017] The 11th disclosure of the present application is the recycling method of the 10th disclosure, characterized in that the drum unit further includes a spring that presses the cleaning roller toward the photosensitive drum, and the replacement process involves replacing the cleaning roller and the spring.

[0018] The 12th disclosure of the present application is a recycling method according to any one of the 1st to 11th disclosures, characterized in that in the measurement process, the measurement value is input into a computer, the computer has a memory that stores the first threshold value, and in the judgment process, the computer judges whether the measurement value is greater than or equal to the first threshold value read from the memory. [Effects of the Invention]

[0019] According to the first to twelfth disclosures, the state of the cleaning roller can be determined without disassembling the drum unit. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a schematic diagram of an image forming apparatus. [Figure 2] FIG. 2 is a perspective view of the drum unit. [Figure 3] FIG. 2 is a vertical cross-sectional view of the drum unit. [Figure 4] FIG. 4 is a cross-sectional view of the drum unit taken along line AA in FIG. 3. [Figure 5] FIG. 4 is a cross-sectional view of the drum unit taken along line BB in FIG. 3. [Figure 6] 3 is a flowchart showing a processing flow in the first embodiment. [Figure 7] FIG. 2 is a diagram showing a processing state of the first embodiment. [Figure 8]FIG. 10 is a diagram showing a processing state of the second embodiment. [Figure 9] 10 is a flowchart showing a processing flow according to a third embodiment. [Figure 10] FIG. 10 is a diagram showing a processing state of the third embodiment. [Figure 11] FIG. 10 is a diagram showing a processing state of a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following, a direction parallel to the rotation axis of the cleaning roller 40 will be referred to as a "first direction." Furthermore, a direction in which the photosensitive drum 30 and the cleaning roller 40 are aligned will be referred to as a "second direction." The first direction and the second direction intersect with each other. Preferably, the first direction and the second direction are perpendicular to each other.

[0022] <1. Configuration of image forming device> FIG. 1 is a schematic diagram of an image forming apparatus 100. The image forming apparatus 100 is an electrophotographic printer. Specifically, the image forming apparatus 100 is a laser printer or an LED printer. As shown in FIG. 1, the image forming apparatus 100 includes a main body frame 101, a drum unit 2, and four developing cartridges 1.

[0023] Toner, which is a developer, is accommodated inside the developer cartridge 1. The four developer cartridges 1 accommodate toner of different colors. Each developer cartridge 1 has a developer roller 10. The developer roller 10 is rotatably supported on the housing of the developer cartridge 1. The developer roller 10 has a cylindrical outer surface extending in a first direction. The toner accommodated inside the developer cartridge 1 is carried on the outer surface of the developer roller 10.

[0024] The four developer cartridges 1 can be attached to the drum unit 2. Furthermore, the drum unit 2 with the four developer cartridges 1 attached can be attached to the main body frame 101. The image forming device 100 prints an image on the surface of printing paper using toner supplied from the developer cartridges 1.

[0025] 2 is a perspective view of the drum unit 2. As shown in FIGS.

[0026] The drum frame 20 is a frame that supports four photosensitive drums 30. Four developer cartridges 1 can be attached to the drum frame 20. The photosensitive drums 30 are cylindrical members that extend along a first direction. The photosensitive drums 30 are rotatable about a drum axis Ad (see Figures 4 and 5) that extends in the first direction. The outer surfaces of the photosensitive drums 30 are covered with a photosensitive material.

[0027] When the developer cartridge 1 is mounted in the drum frame 20, the outer circumferential surface of the developer roller 10 comes into contact with the outer circumferential surface of the photosensitive drum 30. The toner in the developer cartridge 1 is supplied to the outer circumferential surface of the photosensitive drum 30 via the outer circumferential surface of the developer roller 10. Then, the toner carried on the outer circumferential surface of the photosensitive drum 30 is transferred to the printing paper.

[0028] <2. Cleaning roller and cleaning shaft> Fig. 3 is a longitudinal cross-sectional view of the drum unit 2. Fig. 3 shows a cross section perpendicular to the first direction. Fig. 4 is a cross-sectional view of the drum unit 2 taken along line AA in Fig. 3. Fig. 5 is a cross-sectional view of the drum unit 2 taken along line BB in Fig. 3. As shown in Figs. 3 and 4, the drum unit 2 includes a cleaning roller 40 and a cleaning shaft 50.

[0029] The cleaning roller 40 is a roller for cleaning the outer peripheral surface of the photosensitive drum 30. The cleaning roller 40 is rotatable about a first axis A1 extending in a first direction. The cleaning roller 40 has a roller shaft 41 and a roller main body 42.

[0030] The roller shaft 41 is a cylindrical member extending along the first axis A1. The roller shaft 41 is made of metal or conductive resin. The roller shaft 41 penetrates the roller body 42 and extends in the first direction. The roller shaft 41 is rotatably supported by the drum frame 20.

[0031] The roller body 42 is a cylindrical member centered on the first axis A1. The roller body 42 is made of elastically deformable rubber or sponge. The roller body 42 is fixed to the periphery of the roller shaft 41. The outer circumferential surface of the roller body 42 contacts the outer circumferential surface of the photosensitive drum 30. The roller body 42 is porous. For this reason, the outer circumferential surface of the roller body 42 is more susceptible to wear than the photosensitive drum 30 and the cleaning shaft 50.

[0032] With the drum unit 2 attached to the main body frame 101, the image forming apparatus 100 supplies a first voltage to the roller shaft 41. After the toner is transferred from the photosensitive drum 30 to the printing paper, the toner remaining on the outer circumferential surface of the photosensitive drum 30 is moved from the outer circumferential surface of the photosensitive drum 30 to the outer circumferential surface of the cleaning roller 40 by electrostatic force due to the first voltage of the roller shaft 41. This removes the toner from the outer circumferential surface of the photosensitive drum 30.

[0033] Furthermore, the outer peripheral surface of the cleaning roller 40 rotates at a different rotation speed relative to the outer peripheral surface of the photosensitive drum 30. As a result, paper dust adhering to the outer peripheral surface of the photosensitive drum 30 is scraped off and transferred to the outer peripheral surface of the cleaning roller 40.

[0034] The cleaning shaft 50 is a member for removing paper dust from the cleaning roller 40. The cleaning shaft 50 is rotatable about a second axis A2 extending in the first direction. The cleaning shaft 50 has a cylindrical shape extending in the first direction. The cleaning shaft 50 is made of metal or conductive resin.

[0035] The cleaning shaft 50 is rotatably supported by the drum frame 20. The outer circumferential surface of the cleaning shaft 50 contacts the outer circumferential surface of the cleaning roller 40.

[0036] With the drum unit 2 attached to the main body frame 101, the image forming apparatus 100 supplies a second voltage to the cleaning shaft 50. The second voltage supplied to the cleaning shaft 50 is different from the first voltage. The paper dust adhering to the outer surface of the cleaning roller 40 is moved from the outer surface of the cleaning roller 40 to the outer surface of the cleaning shaft 50 by the electrostatic force caused by the second voltage of the cleaning shaft 50. This removes the paper dust from the outer surface of the cleaning roller 40.

[0037] 4 and 5, the drum unit 2 also includes a bearing member 60. The bearing member 60 is a single member having a first bearing hole 61 and a second bearing hole 62. An end of the roller shaft 41 of the cleaning roller 40 is inserted into the first bearing hole 61. An end of the cleaning shaft 50 is inserted into the second bearing hole 62. As a result, the cleaning roller 40 and the cleaning shaft 50 are each rotatably supported while maintaining a constant distance between the first shaft A1 and the second shaft A2.

[0038] As shown in FIG. 4 , the drum unit 2 also includes a spring 70. The spring 70 is an elastic member that can expand and contract in the second direction. One end of the spring 70 in the second direction is connected to the bearing member 60. The other end of the spring 70 in the second direction is connected to the drum frame 20. The spring 70 is compressed in the second direction beyond its natural length. Therefore, the spring 70 presses the bearing member 60 in the second direction toward the photosensitive drum 30.

[0039] As described above, the roller shaft 41 and the cleaning shaft 50 are supported by the bearing member 60. Therefore, the spring 70 presses the bearing member 60, the cleaning roller 40, and the cleaning shaft 50 together toward the photosensitive drum 30. This allows the cleaning roller 40 to come into contact with the photosensitive drum 30 while the cleaning roller 40 and the cleaning shaft 50 are in contact with each other.

[0040] 3 and 5, the drum unit 2 is also provided with a paper dust collection box 80. The paper dust collection box 80 is a container that collects paper dust from the cleaning shaft 50. The paper dust collection box 80 has a blade 81. The blade 81 is made of an elastic material such as urethane. The blade 81 comes into contact with the outer circumferential surface of the cleaning shaft 50. As a result, the paper dust adhering to the outer circumferential surface of the cleaning shaft 50 is scraped off by the blade 81 and collected in the paper dust collection box 80.

[0041] The paper dust collection box 80 is fixed to the bearing member 60. This maintains a constant positional relationship between the cleaning shaft 50 and the paper dust collection box 80. Therefore, the blade 81 of the paper dust collection box 80 can effectively collect paper dust from the cleaning shaft 50.

[0042] <3. Recycling of cleaning rollers> Next, a method for determining whether or not the cleaning roller 40 can be recycled when recycling a used drum unit 2 will be described.

[0043] <3-1. First embodiment> First, a process of a first embodiment for determining whether the cleaning roller 40 can be recycled will be described. FIG. 6 is a flowchart showing the process flow of the first embodiment. FIG. 7 is a diagram showing the process of the first embodiment. In this first embodiment, a measuring device 90 including a pressure-sensitive element 91 is used. The pressure-sensitive element 91 is a sheet-like element. The pressure-sensitive element 91 measures the pressure applied to its surface and outputs a measurement signal corresponding to the pressure.

[0044] When determining whether the cleaning roller 40 can be recycled, first, a pressure-sensitive element 91 is inserted between the photosensitive drum 30 and the cleaning roller 40, which are assembled to the drum frame 20 (step S1). Specifically, with the tip of the pressure-sensitive element 91 inserted between the photosensitive drum 30 and the cleaning roller 40, the photosensitive drum 30 and the cleaning roller 40 are rotated. This causes the pressure-sensitive element 91 to be drawn between the photosensitive drum 30 and the cleaning roller 40. As a result, the pressure-sensitive element 91 is sandwiched between the photosensitive drum 30 and the cleaning roller 40, as shown in FIG. 7 .

[0045] Next, the measuring device 90 acquires the measurement value V output from the pressure-sensitive element 91 (step S2: measurement step). The measurement value V output from the pressure-sensitive element 91 is a value that reflects the nip pressure between the photosensitive drum 30 and the cleaning roller 40. The nip pressure is the pressure with which the cleaning roller 40 is pressed against the photosensitive drum 30. As the nip pressure decreases, the ability of the cleaning roller 40 to collect toner and paper dust from the photosensitive drum 30 also decreases.

[0046] 7, the measuring instrument 90 is electrically connected to a computer 92. The measuring instrument 90 inputs a measurement value V output from a pressure-sensitive element 91 to the computer 92. A first threshold value V1 related to the measurement value V is stored in the memory of the computer 92. The computer 92 determines whether the measurement value V input from the measuring instrument 90 is equal to or greater than the first threshold value V1 read from the memory (step S3, determination step).

[0047] The roller body 42 of the cleaning roller 40 may wear out or lose elasticity with use. Also, the force of the spring 70 pressing the cleaning roller 40 may weaken with use. In these cases, the nip pressure between the photosensitive drum 30 and the cleaning roller 40 decreases. Therefore, the measurement value V input from the measuring device 90 also decreases.

[0048] If the computer 92 determines that the measurement value V is equal to or greater than the first threshold value V1 (Yes in step S3), it determines that the cleaning roller 40 is recyclable (step S4). In this case, the computer 92 may display on a display that the cleaning roller 40 is recyclable.

[0049] On the other hand, if the computer 92 determines that the measurement value V is less than the first threshold value V1 (No in step S3), it determines that the cleaning roller 40 cannot be recycled (step S5). In this case, the computer 92 may display on a display that the cleaning roller 40 cannot be recycled.

[0050] If the computer 92 determines that the cleaning roller 40 is recyclable, the cleaning roller 40 is reused (step S6). If other parts in the drum unit 2, such as the photosensitive drum 30 and the charger, are also reusable, only cleaning is performed and the drum unit 2 is reused without disassembly. On the other hand, if the computer 92 determines that the cleaning roller 40 is not recyclable, the cleaning roller 40 is replaced (step S7: replacement process).

[0051] In the replacement process of step S7, the worker replaces the cleaning roller 40 with a new cleaning roller 40. However, the worker may replace not only the cleaning roller 40 but also the spring 70 with a new spring 70.

[0052] As described above, in this embodiment, with the photosensitive drum 30 and cleaning roller 40 assembled in the drum frame 20, the measurement value V reflecting the nip pressure between the photosensitive drum 30 and the cleaning roller 40 is obtained by the measuring device 90. Then, it is determined whether the measurement value V is equal to or greater than the first threshold value V1. This makes it possible to determine the condition of the cleaning roller 40 without disassembling the drum unit 2. Therefore, it is possible to determine whether the cleaning roller 40 is recyclable without disassembling the drum unit 2.

[0053] In the measurement step of step S2, the measurement values V may be obtained at multiple positions in the first direction. For example, the measuring instrument 90 may perform measurements using the pressure-sensitive element 91 at three locations of the contact portion between the photosensitive drum 30 and the cleaning roller 40: near one end in the first direction, at the center in the first direction, and near the other end in the first direction. The number of measurement locations may be two, or may be four or more. In this case, in the determination step of step S3, for example, the computer 92 may determine whether all of the multiple measurement values V are equal to or greater than the first threshold value V1.

[0054] Furthermore, if there is a difference in nip pressure at multiple positions in the first direction, the cleaning roller 40 may not be able to collect toner uniformly in the first direction. Therefore, a second threshold value V2 related to the difference between the maximum and minimum values of the measurement values V may be stored in the memory of the computer 92. In this case, the computer 92 may determine whether the difference between the maximum and minimum values of the multiple measurement values V is equal to or smaller than the second threshold value V2. If the computer 92 determines that the difference between the maximum and minimum values of the multiple measurement values V is greater than the second threshold value V2, it may determine that the cleaning roller 40 is not recyclable.

[0055] <3-2. Second embodiment> Next, a description will be given of a process of a second embodiment for determining whether the cleaning roller 40 can be recycled. Fig. 8 is a diagram showing the process of the second embodiment. In this second embodiment, a measuring device 90 including a pressure-sensitive element 91 is also used.

[0056] The process flow in the second embodiment is the same as the process flow in the first embodiment, except that, whereas in the first embodiment, the pressure-sensitive element 91 is inserted between the photosensitive drum 30 and the cleaning roller 40, in the second embodiment, the pressure-sensitive element 91 is inserted between the cleaning roller 40 and the cleaning shaft 50, as shown in FIG.

[0057] The measuring instrument 90 obtains a measurement value V that reflects the nip pressure between the cleaning roller 40 and the cleaning shaft 50 using the pressure-sensitive element 91. The measuring instrument 90 inputs the measurement value V output from the pressure-sensitive element 91 to the computer 92. The computer 92 then determines whether the measurement value V is equal to or greater than a first threshold value V1. Because the metal cleaning shaft 50 is resistant to wear, the measurement value V changes depending on the condition of the cleaning roller 40, which is relatively susceptible to wear. Therefore, by determining whether the measurement value V is equal to or greater than the first threshold value V1, the condition of the cleaning roller 40 can be determined without disassembling the drum unit 2. Therefore, it can be determined whether the cleaning roller 40 can be recycled without disassembling the drum unit 2.

[0058] <3-3. Third embodiment> Next, a process of a third embodiment for determining whether the cleaning roller 40 can be recycled will be described. Fig. 9 is a flowchart showing the process flow of the third embodiment. Fig. 10 is a diagram showing the process of the third embodiment. In this third embodiment, a measuring device 90 including a force gauge 93 and a sheet 94 connected to a measurement axis 931 of the force gauge 93 is used.

[0059] The force gauge 93 is a push-pull gauge capable of measuring the tensile force and the pressing force applied to the measurement axis 931. However, the force gauge 93 may be a gauge capable of measuring only the tensile force applied to the measurement axis 931. The sheet 94 is made of, for example, paper. However, the sheet 94 may also be made of a resin film or the like.

[0060] When determining whether the cleaning roller 40 is recyclable, first, a sheet 94 is inserted between the photosensitive drum 30 and the cleaning roller 40, which are assembled to the drum frame 20 (step S1). Specifically, with the leading edge of the sheet 94 inserted between the photosensitive drum 30 and the cleaning roller 40, the photosensitive drum 30 and the cleaning roller 40 are rotated. This causes the sheet 94 to be pulled between the photosensitive drum 30 and the cleaning roller 40. As a result, the sheet 94 is sandwiched between the photosensitive drum 30 and the cleaning roller 40, as shown in FIG. 10 .

[0061] Next, with the rotation of the photosensitive drum 30 and the cleaning roller 40 stopped, the sheet 94 is pulled out from between the photosensitive drum 30 and the cleaning roller 40 as indicated by the dashed arrow in Fig. 10. Then, the tensile force acting on the measurement shaft 931 just before the sheet 94 starts to move or while the sheet 94 is being pulled out is measured with the force gauge 93 to obtain a measurement value V (step S2: measurement step).

[0062] The measurement value V output from the force gauge 93 represents the frictional force of the sheet 94 against the photosensitive drum 30 and the cleaning roller 40. Therefore, the measurement value V is a value that reflects the nip pressure between the photosensitive drum 30 and the cleaning roller 40. As shown in FIG. 10 , the measuring device 90 is electrically connected to a computer 92. The measuring device 90 inputs the measurement value V output from the force gauge 93 to the computer 92.

[0063] A first threshold value V1 related to the measurement value V is stored in the memory of the computer 92. The computer 92 determines whether the measurement value V input from the measuring instrument 90 is equal to or greater than the first threshold value V1 read from the memory (step S3, determination step).

[0064] The roller body 42 of the cleaning roller 40 may wear out or lose elasticity with use. Also, the force of the spring 70 pressing the cleaning roller 40 may weaken with use. In these cases, the nip pressure between the photosensitive drum 30 and the cleaning roller 40 decreases. Therefore, the measurement value V input from the measuring device 90 also decreases.

[0065] If the computer 92 determines that the measurement value V is equal to or greater than the first threshold value V1 (Yes in step S3), it determines that the cleaning roller 40 is recyclable (step S4). In this case, the computer 92 may display on a display that the cleaning roller 40 is recyclable.

[0066] On the other hand, if the computer 92 determines that the measurement value V is less than the first threshold value V1 (No in step S3), it determines that the cleaning roller 40 cannot be recycled (step S5). In this case, the computer 92 may display on a display that the cleaning roller 40 cannot be recycled.

[0067] If the computer 92 determines that the cleaning roller 40 is recyclable, the cleaning roller 40 is reused (step S6). On the other hand, if the computer 92 determines that the cleaning roller 40 is not recyclable, the cleaning roller 40 is replaced (step S7: replacement step).

[0068] In the replacement process of step S7, the worker replaces the cleaning roller 40 with a new cleaning roller 40. However, the worker may replace not only the cleaning roller 40 but also the spring 70 with a new spring 70.

[0069] As described above, in this embodiment, with the photosensitive drum 30 and cleaning roller 40 assembled in the drum frame 20, the measurement value V reflecting the nip pressure between the photosensitive drum 30 and the cleaning roller 40 is obtained by the measuring device 90. Then, it is determined whether the measurement value V is equal to or greater than the first threshold value V1. This makes it possible to determine the condition of the cleaning roller 40 without disassembling the drum unit 2. Therefore, it is possible to determine whether the cleaning roller 40 is recyclable without disassembling the drum unit 2.

[0070] In the measurement step of step S2, the measurement values V may be obtained at multiple positions in the first direction. For example, the measuring instrument 90 may perform measurements using the force gauge 93 at three locations of the contact portion between the photosensitive drum 30 and the cleaning roller 40: near one end in the first direction, the center in the first direction, and near the other end in the first direction. The number of measurement locations may be two, or may be four or more. In this case, in the determination step of step S3, for example, the computer 92 may determine whether all of the multiple measurement values V are equal to or greater than the first threshold value V1.

[0071] The memory of the computer 92 may also store a second threshold value V2 related to the difference between the maximum and minimum values of the measurement values V. In this case, the computer 92 may determine whether the difference between the maximum and minimum values of the multiple measurement values V is equal to or smaller than the second threshold value V2. If the computer 92 determines that the difference between the maximum and minimum values of the multiple measurement values V is greater than the second threshold value V2, it may determine that the cleaning roller 40 cannot be recycled.

[0072] <3-4. Fourth embodiment> Next, a process of a fourth embodiment for determining whether the cleaning roller 40 can be recycled will be described. Fig. 11 is a diagram showing the process of the fourth embodiment. In this fourth embodiment, a measuring device 90 including a force gauge 93 and a sheet 94 connected to a measurement axis 931 of the force gauge 93 is also used.

[0073] The process flow in the fourth embodiment is the same as the process flow in the third embodiment, except that, whereas in the third embodiment, the sheet 94 is inserted between the photosensitive drum 30 and the cleaning roller 40, in the fourth embodiment, the sheet 94 is inserted between the cleaning roller 40 and the cleaning shaft 50, as shown in FIG.

[0074] With the rotation of the cleaning roller 40 and the cleaning shaft 50 stopped, the measuring device 90 pulls out the sheet 94 from between the cleaning roller 40 and the cleaning shaft 50 as indicated by the dashed arrow in Figure 11. The force gauge 93 measures the tensile force acting on the measuring shaft 931 just before the sheet 94 starts to move or while the sheet 94 is being pulled out, thereby obtaining a measurement value V.

[0075] Measuring instrument 90 inputs the measurement value V output from force gauge 93 to computer 92. Then, computer 92 determines whether measurement value V is equal to or greater than first threshold value V1. This makes it possible to determine the condition of cleaning roller 40 without disassembling drum unit 2. Therefore, it is possible to determine whether cleaning roller 40 can be recycled without disassembling drum unit 2.

[0076] <4. Modifications> The present disclosure is not limited to the above embodiments.

[0077] In the above embodiment, the computer 92 determines whether the measurement value V output from the measuring instrument 90 is equal to or greater than the first threshold value V1. However, the determination whether the measurement value V output from the measuring instrument 90 is equal to or greater than the first threshold value V1 may be made by an operator.

[0078] In the above embodiment, the drum unit 2 includes four photosensitive drums 30. However, the number of photosensitive drums 30 included in the drum unit 2 may be one to three, or may be five or more.

[0079] In the above embodiment, the drum unit 2 includes four cleaning rollers 40. However, the number of cleaning rollers 40 included in the drum unit 2 may be one to three, or may be five or more.

[0080] In the above embodiment, four developer cartridges 1 can be attached to the drum unit 2. However, the number of developer cartridges 1 that can be attached to the drum unit 2 may be one to three, or may be five or more.

[0081] For example, the drum unit 2 may include one photosensitive drum 30, one cleaning roller 40, and one cleaning shaft 50. A plurality of drum units 2, each with one developer cartridge 1 attached, may be mountable to the main body frame 101.

[0082] Furthermore, the developing cartridge 1 does not necessarily have to have the developing roller 10. In that case, the drum unit 2 may have the developing roller 10.

[0083] Furthermore, the elements appearing in the above-described embodiment and modified examples may be combined as appropriate within the scope of not causing any contradiction. [Explanation of symbols]

[0084] 1: Developing cartridge 2: Drum unit 20: Drum frame 30: Photosensitive drum 40: Cleaning roller 50: Cleaning shaft 60: Bearing material 70: Spring 80: Paper dust collection box 90: Measuring instruments 91: Pressure-sensitive element 92: Computer 93: Force gauge 94: Sheet 100: Image forming device 101: Main frame V: Measurement value V1: First threshold V2: Second threshold

Claims

1. Drum frame and A photosensitive drum; a cleaning roller that contacts the photosensitive drum; A method for recycling a used drum unit, comprising: a measuring step of acquiring a measurement value reflecting a nip pressure between the photosensitive drum and the cleaning roller by a measuring instrument in a state in which the photosensitive drum and the cleaning roller are assembled to the drum frame; a determination step of determining whether the measurement value is equal to or greater than a first threshold value; A recycling method comprising the steps of:

2. The recycling method according to claim 1, the meter includes a pressure-sensitive element; The measuring step includes: inserting the pressure-sensitive element between the photosensitive drum and the cleaning roller; acquiring a measurement value output from the pressure-sensitive element as the measurement value; A recycling method comprising:

3. The recycling method according to claim 1 or claim 2, The measuring instrument is Force gauge and a sheet connected to the measurement axis of the force gauge; Including, The measuring step includes: inserting the sheet between the photosensitive drum and the cleaning roller; a recycling method characterized in that the force gauge measures, as the measurement value, a tensile force when the sheet is pulled out from between the photosensitive drum and the cleaning roller while the rotation of the photosensitive drum and the cleaning roller is stopped.

4. Drum frame and A photosensitive drum; a cleaning roller that contacts the photosensitive drum; a cleaning shaft that contacts the cleaning roller; A method for recycling a used drum unit, comprising: a measuring step of acquiring a measurement value reflecting a nip pressure between the cleaning roller and the cleaning shaft by a measuring instrument in a state in which the cleaning roller and the cleaning shaft are assembled to the drum frame; a determination step of determining whether the measurement value is equal to or greater than a first threshold value; A recycling method comprising the steps of:

5. The recycling method according to claim 4, the meter includes a pressure-sensitive element; The measuring step includes: inserting the pressure-sensitive element between the cleaning roller and the cleaning shaft; acquiring a measurement value output from the pressure-sensitive element as the measurement value; A recycling method comprising:

6. The recycling method according to claim 4 or claim 5, The measuring instrument is Force gauge and a sheet connected to the measurement axis of the force gauge; Including, The measuring step includes: inserting the sheet between the cleaning roller and the cleaning shaft; a force gauge measuring, as the measurement value, a tensile force applied when the sheet is pulled out from between the cleaning roller and the cleaning shaft while the rotation of the cleaning roller and the cleaning shaft is stopped.

7. The recycling method according to claim 1, claim 2, claim 4, or claim 5, In the measuring step, the measurement values are obtained at a plurality of positions in a first direction parallel to a rotation axis of the cleaning roller, The recycling method is characterized in that in the determining step, it is determined whether or not all of the plurality of measurement values are equal to or greater than the first threshold value.

8. The recycling method according to claim 7, The recycling method is characterized in that in the determining step, it is determined whether or not the difference between the maximum value and the minimum value of the plurality of measurement values is equal to or less than a second threshold value.

9. The recycling method according to claim 1, claim 2, claim 4, or claim 5, In the determination step, when it is determined that the measurement value is equal to or greater than the first threshold value, it is determined that the cleaning roller is recyclable; The recycling method is characterized in that, in the determining step, if it is determined that the measured value is less than the first threshold value, it is determined that the cleaning roller cannot be recycled.

10. The recycling method according to claim 9, a replacing step of replacing the cleaning roller when it is determined that the cleaning roller cannot be recycled; The recycling method further comprises:

11. The recycling method according to claim 10, The drum unit is A spring that presses the cleaning roller toward the photosensitive drum Furthermore, The recycling method is characterized in that the replacing step includes replacing the cleaning roller and the spring.

12. The recycling method according to claim 1, claim 2, claim 4, or claim 5, In the measuring step, the measurement value is input into a computer, the computer has a memory that stores the first threshold value; The recycling method is characterized in that, in the determining step, the computer determines whether the measured value is equal to or greater than the first threshold value read from the memory.

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