Determination method and determination device

Abstract

To provide a determination device and a determination method that can determine whether an electrifier can be recycled without disassembling an image forming apparatus or a drum unit.SOLUTION: A determination device executes a voltage changing step and a voltage determination step. The voltage changing step includes applying voltage to a wire 331 so that a grid voltage Vg changes between a plurality of preset voltage values. The voltage determination step includes determining whether an electrifier 33 can be recycled on the basis of a change of a wire voltage Vw relative to a change of the grid voltage Vg in the voltage changing step. Consequently, a determination can be made as to whether the electrifier 33 can be recycled without disassembling an image forming apparatus or a drum unit.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a determination method and a determination device. [Background technology]

[0002] Conventionally, electrophotographic image forming apparatuses such as LED printers are known. The electrophotographic image forming apparatuses include a photosensitive drum and a charger that charges the photosensitive drum. The photosensitive drum and the charger may be mounted in a drum unit that is detachable from the image forming apparatus.

[0003] Conventionally, in this type of image forming apparatus, when determining whether the charger can be recycled, it was necessary to disassemble the image forming apparatus or the drum unit and inspect the charger, which resulted in a labor-intensive process.

[0004] Therefore, an image forming apparatus that uses a drum memory to determine whether or not a charger can be recycled is described in Patent Document 1. In Patent Document 1, the image forming apparatus reads out the number of times the wire has been cleaned by a cleaner from the drum memory, and determines whether or not the wire can be reused. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2022-157975 Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, the Scorotron charger disclosed in Patent Document 1 is prone to abnormal discharges such as spark discharges and arc discharges if foreign matter adheres to the wire. Chargers prone to such discharges are not suitable for recycling.

[0007] An object of the present disclosure is to provide a determination method and a determination device that can determine whether a charger can be recycled without disassembling an image forming apparatus or a drum unit, using a method different from the conventional method. [Means for solving the problem]

[0008] The first disclosure of the present application is a method for determining whether a Scorotron type charger used in an electrophotographic image forming apparatus can be recycled by a determination device, the charger having a wire and a grid, and in which a grid voltage, which is the voltage of the grid, changes depending on a wire voltage, which is the voltage applied to the wire, the method comprising: a voltage change step in which the determination device applies a voltage to the wire so that the grid voltage changes between a plurality of preset voltage values; and a voltage determination step in which the determination device determines whether the charger can be recycled based on the change in the wire voltage relative to the change in the grid voltage in the voltage change step.

[0009] A second disclosure of the present application is the determination method of the first disclosure, wherein the determination device increases the grid voltage stepwise in the voltage changing step.

[0010] A third disclosure of the present application is the judgment method of the first or second disclosure, characterized in that, in the voltage judgment process, the judgment device judges that the charger cannot be recycled when the wire voltage is smaller than a predetermined threshold corresponding to the grid voltage.

[0011] A fourth disclosure of the present application is the determination method of the third disclosure, characterized in that the threshold value is set based on a proportional relationship between the grid voltage and the wire voltage when the grid voltage is smaller than a predetermined value.

[0012] A fifth disclosure of the present application is a determination method according to any one of the first to fourth disclosures, characterized in that the charger is used in a drum unit that is detachable from a main body frame of the image forming apparatus.

[0013] A sixth disclosure of the present application is the judgment method of the fifth disclosure, further comprising a reading step in which the judgment device reads out the number of sheets printed by the drum unit from a memory provided in the drum unit, and a number of sheets printed judgment step in which the judgment device judges whether the number of sheets printed read out by the reading step is less than a predetermined value, wherein the judgment device executes the voltage change step and the voltage judgment step if it determines that the number of sheets printed is less than the predetermined value, and wherein the judgment device does not execute the voltage change step and the voltage judgment step if it determines that the number of sheets printed is equal to or greater than the predetermined value.

[0014] A seventh disclosure of the present application is a determination method according to any one of the first to sixth disclosures, characterized in that the determination device further includes a voltage application step in which the determination device applies a voltage to the wire so that the grid voltage is higher than when the charger is in use, and a spark discharge determination step in which the determination device determines that the charger cannot be recycled if a spark discharge occurs in the voltage application step.

[0015] An eighth disclosure of the present application is the determination method of the seventh disclosure, characterized in that the determination device performs the voltage changing step and the voltage determination step after the voltage application step and the spark discharge determination step.

[0016] The ninth disclosure of the present application is a method for determining whether a Scorotron type charger used in an electrophotographic image forming apparatus can be recycled by a determination device, the charger having a wire and a grid, and in which a grid voltage, which is the voltage of the grid, changes depending on a wire voltage, which is the voltage applied to the wire, the method comprising: a voltage application step in which the determination device applies a voltage to the wire so that the grid voltage is higher than when the charger is in use; and a spark discharge determination step in which the determination device determines that the charger cannot be recycled if a spark discharge occurs during the voltage application step.

[0017] A tenth disclosure of the present application is the determination method according to the ninth disclosure, characterized in that the charger is used in a drum unit that is detachable from a main body frame of the image forming apparatus.

[0018] An eleventh disclosure of the present application is the judgment method of the tenth disclosure, further comprising a reading step in which the judgment device reads out the number of sheets printed by the drum unit from a memory provided in the drum unit, and a number of sheets printed judgment step in which the judgment device judges whether the number of sheets printed read out by the reading step is less than a predetermined value, wherein the judgment device executes the voltage application step and the spark discharge judgment step if it determines that the number of sheets printed is less than the predetermined value, and does not execute the voltage application step and the spark discharge judgment step if it determines that the number of sheets printed is equal to or greater than the predetermined value.

[0019] The twelfth disclosure of the present application is a determination device for determining whether a Scorotron type charger used in an electrophotographic image forming apparatus can be recycled, the charger having a wire and a grid, and in which a grid voltage, which is the voltage of the grid, changes depending on a wire voltage, which is the voltage applied to the wire, the determination device comprising: a voltage application circuit for applying a voltage to the charger; and a control unit electrically connected to the voltage application circuit, the control unit executing a voltage change process for changing the grid voltage between a plurality of preset voltage values ​​by the voltage application circuit; and a voltage determination process for determining whether the charger can be recycled based on the change in the wire voltage relative to the change in the grid voltage in the voltage change process.

[0020] A thirteenth disclosure of the present application is a determination device for determining whether a scorotron type charger used in an electrophotographic image forming apparatus can be recycled, the charger having a wire and a grid, and in which a grid voltage, which is the voltage of the grid, changes depending on a wire voltage, which is the voltage applied to the wire, the determination device comprising: a voltage application circuit that applies a voltage to the charger; a spark discharge detection circuit electrically connected to the voltage application circuit, the spark discharge detection circuit being capable of detecting the occurrence of a spark discharge in the charger; and a control unit electrically connected to the voltage application circuit and the spark discharge detection circuit, the control unit executing a voltage application process in which the voltage application circuit applies a voltage to the wire so that the grid voltage is higher than when the charger is in use; and a spark discharge determination process in which the spark discharge detection circuit determines that the charger cannot be recycled if a spark discharge occurs in the voltage application process. Effect of the Invention

[0021] According to the first to thirteenth disclosures of the present application, it is possible to determine whether or not a charger can be recycled without disassembling an image forming apparatus or a drum unit. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a schematic diagram of an image forming apparatus. [Diagram 2] FIG. 2 is a control block diagram of the image forming apparatus. [Diagram 3] FIG. 2 is a circuit diagram of a voltage application circuit. [Figure 4] 10 is a flowchart showing a process for determining whether a charger can be recycled. [Diagram 5] 1 is a graph showing the relationship between grid voltage and wire voltage. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0024] <1. Configuration of image forming device> 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 casing 10, four toner cartridges 20, a drum unit 30, a control unit 40, and a display 50.

[0025] The casing 10 has a box-shaped main body frame 11 and a cover 12. Four toner cartridges 20, a drum unit 30, and a control unit 40 are housed inside the main body frame 11.

[0026] The main body frame 11 has an opening 13. The cover 12 is rotatable between a closed position shown by a two-dot chain line in Fig. 1 and an open position shown by a solid line in Fig. 1. When the cover 12 is disposed in the closed position, the opening 13 of the main body frame 11 is covered by the cover 12. When the cover 12 is disposed in the open position, the opening 13 of the main body frame 11 is exposed.

[0027] The four toner cartridges 20 are detachably attached to the drum unit 30. Toner, which is a developer, is accommodated inside the toner cartridges 20. The four toner cartridges 20 accommodate toner of different colors (for example, cyan, magenta, yellow, and black). Each toner cartridge 20 has a developing roller 21. The developing roller 21 is a cylindrical member extending along a developing shaft. The developing roller 21 is rotatable about the developing shaft. The toner accommodated inside the toner cartridge 20 is supported on the outer surface of the developing roller 21.

[0028] The drum unit 30 is detachable from the main body frame 11. More specifically, the drum unit 30 can be attached to the main body frame 11 with the four toner cartridges 20 attached thereto. That is, the drum unit 30 is used together with the four toner cartridges 20. As shown in FIG. 1, the drum unit 30 has a drum frame 31, four photosensitive drums 32, four chargers 33, and a drum memory 34.

[0029] The drum frame 31 has four slots 311 corresponding to the four toner cartridges 20. One toner cartridge 20 is attached to one slot 311.

[0030] The photoconductor drum 32 is provided for each slot 311. The photoconductor drum 32 is a cylindrical member extending along a drum axis. The photoconductor drum 32 is rotatable about the drum axis. The outer surface of the photoconductor drum 32 is covered with a photosensitive material.

[0031] When the toner cartridge 20 is installed in the slot 311, the outer surface of the developing roller 21 comes into contact with the outer surface of the photosensitive drum 32. The toner in the toner cartridge 20 is supplied to the outer surface of the photosensitive drum 32 via the outer surface of the developing roller 21. Then, the toner carried on the outer surface of the photosensitive drum 32 is transferred to the printing paper.

[0032] A charger 33 is provided for each slot 311. The charger 33 is a device that charges the outer surface of the photoconductor drum 32. In this embodiment, the charger 33 is a scorotron type charger having a wire and a grid. The charger 33 charges the outer surface of the photoconductor drum 32 by corona discharge generated by a voltage applied to the wire.

[0033] The drum memory 34 is a storage medium from which information can be read and written. The drum memory 34 is, for example, a flash ROM or an EEPROM. The drum memory 34 is attached to the drum frame 31. The drum memory 34 stores information about the drum unit 30. Specifically, the drum memory 34 stores identification information for identifying the drum unit 30. The identification information is, for example, a serial number.

[0034] Fig. 2 is a control block diagram of the image forming apparatus 1. As shown in Fig. 2, the drum memory 34 stores the number of sheets N printed by the drum unit 30. The number of sheets N represents the number of times the image forming apparatus 1 has performed printing using one drum unit 30 identified by the identification information. The image forming apparatus 1 increments the number of sheets N printed stored in the drum memory 34 every time it performs one printing.

[0035] The control unit 40 controls the printing process using the drum unit 30. As shown in FIG.

[0036] The processor 41 is, for example, a CPU (Central Processing Unit). The main memory 42 is a storage medium from which information can be read and written. The main memory 42 is, for example, a flash ROM or an EEPROM. The main memory 42 may be disposed on the same board as the processor 41, or may be disposed in another location.

[0037] The main body memory 42 stores a computer program for controlling the operation of the image forming apparatus 1. The processor 41 executes various processes in accordance with the computer program stored in the main body memory 42. Specifically, the processor 41 can execute a printing process and a recyclability determination process, which will be described later.

[0038] 2, when the drum unit 30 is attached to the main body frame 11, the control unit 40 is electrically connected to the drum memory 34. This enables the processor 41 to read information from the drum memory 34 and write information to the drum memory 34.

[0039] 2, the image forming apparatus 1 includes a voltage application circuit 43 and a spark discharge detection circuit 44. The voltage application circuit 43 and the spark discharge detection circuit 44 are electrically connected to the control unit 40.

[0040] The voltage application circuit 43 is an electric circuit for applying a voltage to the charger 33. Fig. 3 is a circuit diagram of the voltage application circuit 43. As described above, the charger 33 in this embodiment has the wire 331 and the grid 332. The wire 331 and the grid 332 are located near the outer surface of the photoconductor drum 32. The grid 332 is located between the outer surface of the photoconductor drum 32 and the wire 331.

[0041] The voltage application circuit 43 has a power supply 431, a resistor 432, and an ammeter 433. The positive terminal of the power supply 431 is connected to the wire 331. The negative terminal of the power supply 431 is grounded to the ground G. This allows the power supply 431 to apply a voltage to the wire 331. Hereinafter, the voltage (potential with respect to the ground G) that the power supply 431 applies to the wire 331 is referred to as a "wire voltage Vw."

[0042] One end of the resistor 432 is connected to the grid 332. The other end of the resistor 432 is grounded to the ground G. The voltage of the grid 332 changes according to the wire voltage Vw. Hereinafter, the voltage of the grid 332 (potential with respect to the ground G) is referred to as the "grid voltage Vg." A current according to the grid voltage Vg flows through the resistor 432. The ammeter 433 measures the value of the current flowing through the resistor 432.

[0043] The grid voltage Vg varies not only with the value of the wire voltage Vw, but also with the state of dust, toner, silica compounds derived from external additives of the toner, and the like attached to the wire 331. Specifically, when dust or toner adheres to the wire 331, the resistance value of the wire 331 increases, and the grid voltage Vg decreases.

[0044] Since the resistance value of the resistor 432 is constant, the grid voltage Vg is proportional to the value of the current flowing through the resistor 432. The control unit 40 feedback controls the wire voltage Vw applied to the wire 331 by the power supply 431 so that the current value measured by the ammeter 433 becomes constant. This keeps the grid voltage Vg constant.

[0045] The spark discharge detection circuit 44 is an electric circuit for detecting the occurrence of a spark discharge in the charger 33. A spark discharge is a discharge accompanied by a spark different from a normal corona discharge. A spark discharge is likely to occur when dust or toner adheres locally inside the charger 33. The spark discharge detection circuit 44 detects the occurrence of a spark discharge based on the value of a current flowing through the voltage application circuit 43. More specifically, the voltage application circuit 43 has a transformer (not shown). The spark discharge detection circuit 44 detects the occurrence of a spark discharge when the value of a current flowing through the transformer exceeds a preset allowable range. When the spark discharge detection circuit 44 detects the occurrence of a spark discharge in the image forming apparatus 1 during printing, the control unit 40 stops printing.

[0046] The display 50 displays various information related to the operation of the image forming apparatus 1. The display 50 is located on the outer surface of the main body frame 11. For example, a liquid crystal display is used for the display 50. The display 50 is electrically connected to the control unit 40. The display 50 displays the operating status, errors, and the like of the image forming apparatus 1 based on information output from the control unit 40.

[0047] The control unit 40 drives a motor (not shown) when executing a printing process. The developing roller 21 and the photosensitive drum 32 rotate by the driving force transmitted from this motor. The control unit 40 also applies a voltage to the charger 33 by the voltage application circuit 43 described above. As a result, the outer surface of the photosensitive drum 32 is charged.

[0048] Furthermore, the control unit 40 causes a light source (not shown) to emit light. The light emitted from the light source is irradiated onto the outer surface of the photoconductor drum 32. As a result, an electrostatic latent image is formed on the outer surface of the photoconductor drum 32. The toner supplied from the toner cartridge 20 is supplied onto the electrostatic latent image on the photoconductor drum 32 via the developing roller 21. As a result, a toner image is formed on the outer surface of the photoconductor drum 32.

[0049] The print paper is transported between the photoconductor drum 32 on which the toner image is formed and a transfer belt (not shown). This causes the toner image to be transferred from the outer surface of the photoconductor drum 32 to the print paper. The toner image is then thermally fixed to the print paper in a fixing unit within the image forming apparatus 1. As a result, an image is printed on the print paper.

[0050] <2. How to determine whether chargers can be recycled> Next, a method for determining whether charger 33 can be recycled will be described. In this embodiment, image forming apparatus 1 has a function as a determination device that determines whether charger 33 can be recycled. Fig. 4 is a flowchart showing a process flow for determining whether charger 33 can be recycled by image forming apparatus 1 as a determination device. The process from step S2 in Fig. 4 onwards proceeds as processor 41 of control unit 40 operates according to a computer program.

[0051] When determining whether the charger 33 is recyclable, first, the drum unit 30 is attached to the image forming apparatus 1 as a determination device (step S1). Specifically, the drum unit 30 is attached to the main body frame 11 of the image forming apparatus 1. This electrically connects the control unit 40 and the drum memory 34. In addition, the voltage application circuit 43 and the spark discharge detection circuit 44 are electrically connected to the charger 33.

[0052] Next, the control unit 40 reads the number of prints N from the drum memory 34 (step S2: reading step). A predetermined value as a threshold value for the number of prints N is stored in advance in the main memory 42. The control unit 40 compares the number of prints N read from the drum memory 34 with the predetermined value read from the main memory 42. Then, the control unit 40 determines whether the number of prints N is less than the predetermined value (step S3: print number determination step).

[0053] When the control unit 40 determines that the number of printed sheets N is equal to or greater than a predetermined value (No in step S3), it displays a message or image indicating that an overhaul inspection of the charger 33 is necessary on the display 50 (step S4). In this case, the control unit 40 does not execute the processes in and after step S5, which will be described later.

[0054] On the other hand, when the control unit 40 determines that the number of printed sheets N is less than the predetermined value (Yes in step S3), it executes the process of step S5 and subsequent steps. In this case, the control unit 40 first applies a high voltage to the charger 33 (step S5: voltage application step). Specifically, the control unit 40 applies a voltage to the wire 331 by the voltage application circuit 43 while rotating the photoconductor drum 32. At this time, the voltage application circuit 43 applies a voltage to the wire 331 so that the grid voltage Vg is higher than that during normal use of the charger 33. For example, when the maximum value of the grid voltage Vg during printing in the image forming apparatus 1 is 800V, the voltage is applied to the wire 331 so that the grid voltage Vg becomes 900V, which exceeds the maximum value. The time for applying the voltage may be, for example, 5 to 15 seconds.

[0055] The control unit 40 determines whether or not a spark discharge has occurred in the charger 33 in the above-mentioned voltage application step (step S6: spark discharge determination step). Specifically, the control unit 40 determines whether or not the spark discharge detection circuit 44 has detected the occurrence of a spark discharge.

[0056] More specifically, the spark discharge detection circuit 44 includes resistors, capacitors, transistors, etc. When a spark discharge occurs, a large current flows instantaneously through the spark discharge detection circuit 44. When the value of the current flowing through the spark discharge detection circuit 44 reaches or exceeds a predetermined value, the spark discharge detection circuit 44 outputs a voltage different from that when a normal discharge, i.e., a corona discharge, is occurring. When the control unit 40 detects that a voltage different from that in normal times is output from the spark discharge detection circuit 44, it determines that a spark discharge has occurred.

[0057] When the control unit 40 determines that a spark discharge has occurred in the voltage application process (Yes in step S6), it determines that recycling of the charger 33 is not possible. In this case, the control unit 40 displays a message or an image on the display 50 indicating that recycling of the charger 33 is not possible (step S7).

[0058] On the other hand, if the control unit 40 determines that no spark discharge has occurred in the voltage application process (No in step S6), then the control unit 40 gradually changes the voltage applied to the charger 33 (step S8: voltage changing process). Specifically, the control unit 40 gradually changes the voltage applied to the wire 331 from the voltage application circuit 43, thereby gradually changing the grid voltage Vg.

[0059] In this voltage changing step, the voltage application circuit 43 changes the grid voltage Vg among a plurality of preset voltage values. For example, the voltage application circuit 43 increases the grid voltage Vg stepwise at intervals of 200 V from 100 to 900 V. Then, the control unit 40 stores the relationship between the grid voltage Vg and the wire voltage Vw applied to the wire 331 at that grid voltage Vg.

[0060] In the example mentioned above in which the grid voltage Vg is increased in steps of 200 V from 100 V to 900 V, the control unit 40 stores the wire voltage Vw when the grid voltage Vg is 100 V, stores the wire voltage Vw when the grid voltage Vg is 300 V, stores the wire voltage Vw when the grid voltage Vg is 500 V, stores the wire voltage Vw when the grid voltage Vg is 700 V, and stores the wire voltage Vw when the grid voltage Vg is 900 V.

[0061] FIG. 5 is a graph showing an example of the grid voltage Vg and the wire voltage Vw measured in the voltage changing process. The horizontal axis of FIG. 5 represents the grid voltage Vg. The vertical axis of FIG. 5 represents the wire voltage Vw. When no arc discharge occurs between the wire 331 and the grid 332, the wire voltage Vw changes with respect to the grid voltage Vg at a substantially constant rate, as shown by the dotted line in FIG. 5. However, when an arc discharge occurs between the wire 331 and the grid 332, the wire voltage Vw drops, as shown by Vwa in FIG. 5.

[0062] Arc discharge occurs between the wire 331 and the grid 332 when a large amount of dust or toner adheres to the charger 33. When an arc discharge occurs, the wire voltage Vw stabilizes at a value lower than normal. Arc discharge can cause poor printing due to insufficient charging of the photoconductor drum 32. Note that this arc discharge cannot be detected by the spark discharge detection circuit 44.

[0063] The control unit 40 sets a threshold value for the wire voltage Vw based on the proportional relationship between the grid voltage Vg and the wire voltage Vw in a region where the grid voltage Vg is smaller than a predetermined reference value (hereinafter referred to as the "low voltage region A1"). The predetermined reference value is, for example, 500V. Specifically, the control unit 40 sets a threshold line Vw0 with a constant slope as shown in the graph of FIG. 5. The slope of the threshold line Vw0 may be the slope of the change in the wire voltage Vw with respect to the grid voltage Vg measured in the low voltage region A1, or may be a fixed value stored in advance. The threshold line Vw0 is set at a position smaller than the wire voltage Vw measured in the low voltage region A1 by a predetermined offset value Vwd. The offset value Vwd is, for example, 500V.

[0064] The control unit 40 determines whether or not the wire voltage Vw is smaller than the threshold line Vw0 in a region where the grid voltage Vg is larger than the above-mentioned reference value (hereinafter referred to as "high voltage region A2") (step S9: voltage determination step).

[0065] In the high voltage region A2, when the wire voltage Vw is smaller than the threshold line Vw0, there is a possibility that an arc discharge is occurring between the wire 331 and the grid 332. Therefore, when the wire voltage Vw is smaller than the threshold line Vw0 in the high voltage region A2 (Yes in step S9), the control unit 40 determines that recycling of the charger 33 is not possible. In that case, the control unit 40 displays on the display 50 a message or image indicating that recycling of the charger 33 is not possible (step S7).

[0066] On the other hand, in the high voltage region A2, when the wire voltage Vw is equal to or greater than the threshold line Vw0, it is considered that no arc discharge is occurring between the wire 331 and the grid 332. Therefore, in the high voltage region A2, when the wire voltage Vw is equal to or greater than the threshold line Vw0 (No in step S9), the control unit 40 determines that the charger 33 is recyclable. In that case, the control unit 40 displays on the display 50 a message or image indicating that the charger 33 is recyclable (step S10).

[0067] As described above, in steps S5 to S6, the control unit 40 supplies a grid voltage Vg to the grid 332 that is higher than that when the charger 33 is in use, and determines whether or not the charger 33 is recyclable based on whether or not a spark discharge occurs. Therefore, it is possible to determine whether or not the charger 33 is recyclable without disassembling the drum unit 30.

[0068] As described above, the control unit 40 changes the grid voltage Vg between a plurality of voltage values, and determines whether the charger 33 is recyclable based on the change in the wire voltage Vw relative to the change in the grid voltage Vg. Therefore, it is possible to determine whether the charger 33 is recyclable without disassembling the drum unit 30.

[0069] Although the above describes the process of determining whether one charger 33 of the drum unit 30 is recyclable, the other chargers 33 of the drum unit 30 may be similarly determined whether they are recyclable.

[0070] <3. Modifications> Although one embodiment of the present disclosure has been described above, the present disclosure is not limited to the above embodiment.

[0071] In the above embodiment, the image forming apparatus 1 plays the role of the determination apparatus. However, the determination apparatus may be a device separate from the image forming apparatus 1 that performs printing. For example, the determination apparatus may be a device installed in a factory that is dedicated to determining whether or not an item can be recycled.

[0072] In the above embodiment, the control unit 40 executes the print number determination step of step S3 before executing the voltage application step, the spark discharge determination step, the voltage change step, and the voltage determination step from step S5 onwards. However, the print number determination step may be omitted. In other words, the control unit 40 may execute the processes from step S5 onwards regardless of the print number N.

[0073] In the above embodiment, the control unit 40 first determines whether or not recycling is possible through the voltage application step and the spark discharge determination step (steps S5 to S6), and then determines whether or not recycling is possible through the voltage change step and the voltage determination step (steps S8 to S9). However, the control unit 40 may first determine whether or not recycling is possible through the voltage change step and the voltage determination step (steps S8 to S9), and then determine whether or not recycling is possible through the voltage application step and the spark discharge determination step (steps S5 to S6).

[0074] In the above embodiment, the control unit 40 performs both the determination of whether or not recycling is possible through the voltage application step and the spark discharge determination step (steps S5 to S6) and the determination of whether or not recycling is possible through the voltage change step and the voltage determination step (steps S8 to S9). However, the control unit 40 may perform only one of the determination of whether or not recycling is possible through the voltage application step and the spark discharge determination step (steps S5 to S6) and the determination of whether or not recycling is possible through the voltage change step and the voltage determination step (steps S8 to S9).

[0075] In the above embodiment, the drum unit 30 includes four photosensitive drums 32. However, the number of photosensitive drums 32 included in the drum unit 30 may be one to three, or may be five or more.

[0076] In the above embodiment, the drum unit 30 includes four chargers 33. However, the number of chargers 33 included in the drum unit 30 may be one to three, or may be five or more.

[0077] In the above embodiment, four toner cartridges 20 can be attached to the drum unit 30. However, the number of toner cartridges 20 that can be attached to the drum unit 30 may be one to three, or may be five or more.

[0078] For example, the drum unit 30 may include one photosensitive drum 32 and one charger 33. A plurality of drum units 30, each having one toner cartridge 20 attached thereto, may be mountable on the main body frame 11.

[0079] Furthermore, the toner cartridge 20 does not necessarily have to have the developing roller 21. In that case, the drum unit 30 may have the developing roller 21.

[0080] In the above embodiment, the drum unit 30 includes the charger 33. However, the main body frame 11 of the image forming apparatus 1 may include the charger 33.

[0081] Furthermore, the elements appearing in the above-described embodiment and modified examples may be combined as appropriate to the extent that no contradiction arises. [Explanation of symbols]

[0082] 1. Image forming device 10 Casing 20 Toner Cartridge 30 Drum unit 31 Drum Frame 32 Photoconductor drum 33 Charger 34 Drum Memory 40 Control section 43 Voltage application circuit 44 Spark discharge detection circuit 50 Display 331 Wire 332 Grid 431 Power supply 432 resistor 433 Ammeter Vg Grid voltage Vw Wire Voltage

Claims

1. A method for determining whether a scorotron charger used in an electrophotographic image forming apparatus is recyclable, the charger having a wire and a grid, and a grid voltage that is a voltage of the grid, changes in response to a wire voltage that is a voltage applied to the wire, by a determination device, comprising: a voltage changing step of applying a voltage to the wire by the determination device so that the grid voltage changes between a plurality of preset voltage values; a voltage determination step in which the determination device determines whether the charger can be recycled based on a change in the wire voltage relative to a change in the grid voltage in the voltage changing step; A method for determining whether a particular

2. The method of claim 1, The determination method, wherein the determination device increases the grid voltage step stepwise in the voltage changing step.

3. The method of claim 2, further comprising: The determination method, wherein the determination device determines that the charger cannot be recycled when the wire voltage is lower than a predetermined threshold value corresponding to the grid voltage in the voltage determination step.

4. The method of claim 3, further comprising: The method of claim 1, wherein the threshold value is set based on a proportional relationship between the grid voltage and the wire voltage when the grid voltage is smaller than a predetermined value.

5. The method of claim 1, The determination method, wherein the charger is used in a drum unit that is detachable from a main body frame of the image forming apparatus.

6. The method of claim 5, further comprising: a reading step in which the determination device reads out the number of sheets printed by the drum unit from a memory included in the drum unit; a print number determination step in which the determination device determines whether the print number read out by the reading step is less than a predetermined value; and when it is determined that the number of printed sheets is less than the predetermined value, the determination device executes the voltage changing step and the voltage determination step; The determination method, wherein the determination device does not execute the voltage change step and the voltage determination step when it determines that the number of printed sheets is equal to or greater than the predetermined value.

7. The method of claim 1, a voltage application step in which the determination device applies a voltage to the wire so that the grid voltage is higher than that when the charger is in use; a spark discharge determination step in which the determination device determines that recycling of the charger is not possible when a spark discharge occurs in the voltage application step; The method for determining whether or not a patient has a blood vessel is further characterized by the following:

8. The method of claim 7, further comprising: The determination method, wherein the determination device performs the voltage changing step and the voltage determination step after the voltage application step and the spark discharge determination step.

9. A method for determining whether a scorotron charger used in an electrophotographic image forming apparatus is recyclable, the charger having a wire and a grid, and a grid voltage that is a voltage of the grid, changes in response to a wire voltage that is a voltage applied to the wire, by a determination device, comprising: a voltage application step in which the determination device applies a voltage to the wire so that the grid voltage is higher than that when the charger is in use; a spark discharge determination step in which the determination device determines that recycling of the charger is not possible when a spark discharge occurs in the voltage application step; A method for determining whether a particular

10. The method of claim 9, further comprising: The determination method, wherein the charger is used in a drum unit that is detachable from a main body frame of the image forming apparatus.

11. The method of claim 10, further comprising: a reading step in which the determination device reads out the number of sheets printed by the drum unit from a memory included in the drum unit; a print number determination step in which the determination device determines whether the print number read out by the reading step is less than a predetermined value; and When the determination device determines that the number of printed sheets is less than the predetermined value, the determination device executes the voltage application step and the spark discharge determination step, The determination method, wherein the determination device does not execute the voltage application step and the spark discharge determination step when it determines that the number of printed sheets is equal to or greater than the predetermined value.

12. A determination device for determining whether a scorotron type charger used in an electrophotographic image forming apparatus can be recycled, the charger having a wire and a grid, and a grid voltage that is a voltage of the grid, which varies depending on a wire voltage that is a voltage applied to the wire, comprising: a voltage application circuit that applies a voltage to the charger; A control unit electrically connected to the voltage application circuit; Equipped with The control unit is a voltage changing step of changing the grid voltage between a plurality of preset voltage values ​​by the voltage application circuit; a voltage determination step of determining whether the charger can be recycled based on a change in the wire voltage relative to a change in the grid voltage in the voltage changing step; A determination device that executes the above.

13. A determination device for determining whether a scorotron type charger used in an electrophotographic image forming apparatus can be recycled, the charger having a wire and a grid, and a grid voltage that is a voltage of the grid, which varies depending on a wire voltage that is a voltage applied to the wire, comprising: a voltage application circuit that applies a voltage to the charger; a spark discharge detection circuit electrically connected to the voltage application circuit and capable of detecting the occurrence of a spark discharge in the charger; a control unit electrically connected to the voltage application circuit and the spark discharge detection circuit; Equipped with The control unit is a voltage application step of applying a voltage to the wire by the voltage application circuit so that the grid voltage is higher than that when the charger is in use; a spark discharge determination step of determining that recycling of the charger is not possible when the spark discharge occurs in the voltage application step by the spark discharge detection circuit; A determination device that executes the above.

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