EP4636498A2

EP4636498A2 - Method of recycling developing cartridge, and image forming apparatus

Info

Publication number: EP4636498A2
Application number: EP25165565.0A
Authority: EP
Inventors: Masahiko Hayakawa; Kensuke Miyahara
Original assignee: Brother Industries Ltd
Current assignee: Brother Industries Ltd
Priority date: 2024-03-25
Filing date: 2025-03-24
Publication date: 2025-10-22
Also published as: EP4636498A3; JP2025147424A

Abstract

Provided is a method of recycling a developing cartridge including: a developing roller; and a casing. The method includes: a refilling step; and a developing roller rotating step. The refilling step includes refilling the casing with new toner after use of the developing cartridge. The developing roller rotating step includes rotating the developing roller for a first time period. The first time period is set based on a difference between a first charge amount and a second charge amount. The first charge amount indicates an electric charge amount of old toner accommodated in the casing before the use of the developing cartridge. The second charge amount indicates an electric charge amount of the new toner. The first time period set when the difference equals a first difference value is longer than the first time period set when the difference equals a second difference value smaller than the first difference value.

Description

The present disclosure relates to a method of recycling a developing cartridge, and an image forming apparatus.
A method known in the art for recycling used developing cartridges involves utilizing the charge amount of toner stored in a developer information storing means of the used developing cartridge (see Japanese Patent Application Publication No. H05-210304 ). With this method, the charge amount of toner stored in the developer information storing means is compared to the charge amount of new toner to be used for refilling the developing cartridge. When the charge amounts of the new and old toner are not the same, the used developing cartridge is first cleaned before being refilled with the new toner. When the charge amounts of the new and old toner are the same, the used developing cartridge is not cleaned but simply refilled with the new toner.
However, when the developing cartridge is cleaned without being disassembled in this conventional method, for example, some of the old toner may remain in the corners of a cartridge frame. When a developing cartridge containing residual old toner is recycled by refilling the developing cartridge with new toner, the old toner and new toner mix together when the recycled developing cartridge is used in an image forming apparatus. This mixing may generate toner whose charge amount has dropped to a level where the toner can no longer be retained on the developing roller, which may result in the low-charged toner leaking out of the developing cartridge.
In view of the foregoing, it is an object of the present disclosure to provide a method of recycling developing cartridges that suppresses toner from leaking out of a recycled developing cartridge when the recycled developing cartridge is used in an image forming apparatus.

(1) In order to attain the above and other object, according to aspect (1), the present disclosure provides a method of recycling a developing cartridge. The developing cartridge includes: a developing roller; a casing; and a memory. The method includes: a refilling step; and a developing roller rotating step. The refilling step includes refilling the casing with new toner after use of the developing cartridge. The developing roller rotating step including rotating the developing roller for a first time period after the refilling step. The first time period is set based on a difference between a first charge amount and a second charge amount. The first charge amount is stored in the memory and indicates an electric charge amount of old toner accommodated in the casing before the use of the developing cartridge. The second charge amount indicates an electric charge amount of the new toner refilled in the casing in the refilling step. The first time period set when the difference equals a first difference value is longer than the first time period set when the difference equals a second difference value smaller than the first difference value.
Here, the amount of toner that leaks out of the developing cartridge when the developing roller rotates increases as the difference between the first charge amount and the second charge amount becomes greater. Therefore, by configuring the method so that the first time period set when the difference between the first charge amount and the second charge amount is greater is longer than the first time period set when the difference between the first charge amount and the second charge amount is smaller, a sufficient amount of toner with a low charge amount can be discharged from the developing cartridge during the developing roller rotating step. As a result, the method suppresses toner leakage from a recycled developing cartridge when the recycled developing cartridge is used in an image forming apparatus.
(2) According to aspect (2), in the method according to aspect (1), it is preferable that the first time period set when the second charge amount equals a first amount value is longer than the first time period set when the second charge amount equals a second amount value greater than the first amount value.
Here, the amount of toner that leaks out of the developing cartridge when the developing roller rotates increases as the second charge amount becomes smaller. Therefore, by configuring the method so that the first time period set when the second charge amount is smaller is longer than the first time period set when the second charge amount is greater, a sufficient amount of toner with a low charge amount can be discharged from the developing cartridge during the developing roller rotating step. As a result, the method suppresses toner leakage from a recycled developing cartridge when the recycled developing cartridge is used in an image forming apparatus.
(3) According to aspect (3), preferably, the method according to aspect (1) or (2) further includes: a first storage step. The first storage step includes storing the second charge amount in the memory.
(4) According to aspect (4), preferably, the method according to aspect (1) or (2) further includes: a setting step; and a second storage step. The setting step includes setting a second time period based on the first charge amount and the second charge amount. The second time period indicates a time period for which an image forming apparatus executes a developing cartridge driving operation. The developing cartridge driving operation includes rotating the developing roller. The second storage step includes storing the second time period in the memory.
(5) According to aspect (5), in the method according to aspect (4), it is preferable that, in the setting step, the second time period set when the difference equals a third difference value is longer than the second time period set when the difference equals a fourth difference value smaller than the third difference value.
When the difference between the first charge amount and the second charge amount is large, there is a high possibility that toner with a charge amount slightly lower than the appropriate value remains mixed in the developing cartridge after the developing roller rotating step is performed. Therefore, by configuring the method so that the second time period set when the difference between the first charge amount and the second charge amount is greater is longer than the second time period when the difference between the first charge amount and the second charge amount is smaller, the method can raise the charge amount of toner with a charge amount slightly lower than the appropriate value during the developing cartridge driving operation.
(6) According to aspect (6), in the method according to aspect (4) or (5), it is preferable that, in the setting step, the second time period set when the second charge amount equals a third amount value is longer than the second time period set when the second charge amount equals a fourth amount value greater than the third amount value.
When the second charge amount is small, there is a high possibility that toner with a charge amount slightly lower than the appropriate value remains mixed in the developing cartridge after the developing roller rotating step is performed. Therefore, by configuring the method so that the second time period set when the second charge amount is smaller is longer than the second time period set when the second charge amount is greater, the method can raise the charge amount of toner with a charge amount slightly lower than the appropriate value during the developing cartridge driving operation.
(7) According to aspect (7), in the method according to any one of aspects (4) to (6), it is preferable that, in the setting step, the second time period is set to be shorter than the first time period.
(8) According to aspect (8), in the method according to any one of aspects (1) to (7), it is preferable that: the memory stores therein usage history information indicating a usage history of the developing cartridge; and the first charge amount is modified using the usage history information.
(9) According to aspect (9), in the method according to aspect (8), it is preferable that the usage history information includes at least one of: a cumulative number of rotations of the developing roller; a cumulative dot count for pixels formed using the developing cartridge; and a cumulative number of sheets printed using the developing cartridge.
(10) According to aspect (10), the present disclosure also provides an image forming apparatus including: a main casing; and a controller. A recycled developing cartridge is detachably mountable in the main casing. The recycled developing cartridge is the developing cartridge that has been recycled according to the method according to aspect (3). The controller is configured to perform: setting; and executing. The setting sets a second time period based on the first charge amount and the second charge amount. The executing executes a developing cartridge driving operation for the second time period set in the setting. The developing cartridge driving operation includes rotating the developing roller of the recycled developing cartridge mounted in the main casing.
(11) According to aspect (11), in the image forming apparatus according to aspect (10), it is preferable that, in the setting, the second time period set when the difference equals a third difference value is longer than the second time period when the difference equals a fourth difference value smaller than the third difference value.
By configuring the image forming apparatus so that the second time period set when the difference between the first charge amount and the second charge amount is greater is longer than the second time period set when the difference between the first charge amount and the second charge amount is smaller, the image forming apparatus can raise the charge amount of toner with a charge amount slightly lower than the appropriate value during the developing cartridge driving operation.
(12) According to aspect (12), in the image forming apparatus according to aspect (10) or (11), it is preferable that, in the setting, the second time period set when the second charge amount equals a third amount value is longer than the second time period set when the second charge amount equals a fourth amount value greater than the third amount value.
By configuring the image forming apparatus so that the second time period set when the second charge amount is smaller is longer than the second time period set when the second charge amount is greater, the image forming apparatus can raise the charge amount of toner with a charge amount slightly lower than the appropriate value during the developing cartridge driving operation.
(13) According to aspect (13), in the image forming apparatus according to any one of aspects (10) to (12), it is preferable that, in the setting, the second time period is set to be shorter than the first time period.
(14) According to aspect (14), the present disclosure further provides an image forming apparatus including: a main casing; and a controller. A recycled developing cartridge is detachably mountable in the main casing. The recycled developing cartridge is the developing cartridge that has been recycled according to the method according to aspect (4). The controller is configured to perform: obtaining; and executing. The obtaining obtains the second time period from the memory of the recycled developing cartridge mounted in the main casing. The executing executes the developing cartridge driving operation for the second time period obtained in the obtaining.
(15) According to aspect (15), in the image forming apparatus according to aspect (14), it is preferable that the second time period is shorter than the first time period.

The present disclosure provides a method of recycling developing cartridges that suppresses toner from leaking out of a recycled developing cartridge when the recycled developing cartridge is used in an image forming apparatus.

Fig. 1 is a diagram illustrating a laser printer.
Fig. 2 is a flowchart illustrating steps in a recycling method according to a first embodiment.
Fig. 3 is a map for setting a first time period.
Figs. 4A through 4C are diagrams illustrating the procedures of the recycling method.
Figs. 5A and 5B are diagrams illustrating the procedures of the recycling method.
Fig. 6 is a flowchart illustrating steps in a process executed by a control unit of the laser printer.
Fig. 7 is a map for setting a second time period.
Fig. 8 a flowchart illustrating steps in a recycling method according to a second embodiment.
Fig. 9 is a flowchart illustrating steps in a process executed by a control unit of a laser printer according to a third embodiment.
Fig. 10 is a flowchart illustrating steps in a recycling method according to a fourth embodiment.
Fig. 11 is a flowchart illustrating steps in a process executed by a control unit of a laser printer according to a fourth embodiment.
Fig. 12 is a flowchart illustrating steps in a recycling method according to a fifth embodiment.

Next, a first embodiment of the present invention will be described in detail while referring to the drawings as needed.
Fig. 1 illustrates a laser printer 1 as an example of the image forming apparatus. The laser printer 1 includes a main casing 2, a sheet-feeding unit 3, an exposure device 4, a process cartridge 5, a fixing device 8, and a control unit 100. The control unit 100 is configured with a CPU, RAM, ROM, and input and output circuits, for example.
The sheet-feeding unit 3 is provided in the lower section of the main casing 2. The sheet-feeding unit 3 includes a sheet-feeding tray 31, a pressing plate 32, and a feeding mechanism 33. The sheet-feeding tray 31 accommodates sheets S therein. The pressing plate 32 presses the sheets S upward. The feeding mechanism 33 feeds the sheets S toward the process cartridge 5.
The exposure device 4 is disposed in the upper section of the main casing 2. The exposure device 4 includes a laser light-emitting unit (not illustrated), and a polygon mirror, lenses, reflecting mirrors, and the like not indicated with reference numerals. The exposure device 4 exposes the surface of a photosensitive drum 61 described later to laser light emitted from the laser light-emitting unit.
The process cartridge 5 is disposed below the exposure device 4. The process cartridge 5 is configured to be detachably mounted in the main casing 2 through an opening formed in the front side of the main casing 2. The opening can be exposed by opening a front cover 21 provided on the main casing 2. The process cartridge 5 has a drum cartridge 6, and a developing cartridge 7.
The drum cartridge 6 includes a photosensitive drum 61, a charger 62, and a transfer roller 63.
The developing cartridge 7 can be attached to and detached from the drum cartridge 6. The developing cartridge 7 can be detachably mounted in the main casing 2 via the drum cartridge 6. The developing cartridge 7 includes a developing roller 71, a supply roller 72, a thickness-regulating blade 73, an agitator 74, a casing 75, and a memory 76.
The developing roller 71 supplies toner onto the photosensitive drum 61. The developing roller 71 has a metal shaft, a roller portion covering the outer circumference of the shaft, and a coating layer covering the roller portion. The roller portion of the developing roller 71 is formed of silicone rubber, urethane rubber, or the like. The roller portion of the developing roller 71 contacts the photosensitive drum 61.
The supply roller 72 supplies toner onto the developing roller 71. The supply roller 72 has a metal shaft, and a roller portion that covers the outer circumference of the shaft. The roller portion of the supply roller 72 is formed of a sponge. The roller portion of the supply roller 72 contacts the developing roller 71.
The thickness-regulating blade 73 regulates the thickness of toner carried on the developing roller 71. The thickness-regulating blade 73 has a metal plate, and a rubber portion provided on an edge portion of the metal plate. The rubber portion is formed of a silicone rubber, a urethane rubber, a fluorine-containing rubber, or the like. The rubber portion of the thickness-regulating blade 73 contacts the roller portion of the developing roller 71.
The agitator 74 agitates the toner inside the casing 75. The agitator 74 conveys toner toward the supply roller 72.
The developing roller 71, supply roller 72, and agitator 74 are connected by gears to a coupling (not illustrated). A drive force is transmitted to the coupling from a motor provided in the main casing 2. When the coupling rotates, the developing roller 71, supply roller 72, and agitator 74 also rotate.
The casing 75 can accommodate toner therein. The casing 75 rotatably supports the developing roller 71, supply roller 72, and agitator 74. The casing 75 has a fill hole 75A.
The fill hole 75A is a hole provided for filling and refilling the casing 75 with toner. A cap CP is detachably mounted in the fill hole 75A. The cap CP plugs the fill hole 75A.
The memory 76 stores a first charge amount therein. The first charge amount indicates the electric charge amount of the toner used to fill the developing cartridge 7 at the production plant. Therefore, when a developing cartridge 7 is recycled for the first time, the first charge amount stored in the memory 76 of this developing cartridge 7 corresponds to the charge amount of the toner that was accommodated in the casing 75 when the developing cartridge 7 was new before being shipped for the first time.
The first charge amount in the present embodiment corresponds to the charge amount of new toner that was used to fill the casing 75 of a developing cartridge 7 when the developing cartridge 7 was new before being shipped for the first time and is determined for each production lot. The charge amount of the new toner varies among lots. Therefore, the first charge amount stored in the memory 76 of a given developing cartridge 7 may be a different value from the first charge amount stored in the memory 76 of another developing cartridge 7, for example.
When the laser printer 1 performs printing, the charger 62 charges the surface of the photosensitive drum 61. The exposure device 4 then exposes the surface of the photosensitive drum 61 to form an electrostatic latent image on the photosensitive drum 61. Toner in the casing 75 is subsequently supplied to the developing roller 71 via the agitator 74 and supply roller 72.
The developing roller 71 supplies the toner to the electrostatic latent image on the photosensitive drum 61, thereby forming a toner image on the photosensitive drum 61. Thereafter, the toner image on the photosensitive drum 61 is transferred onto a sheet S as the sheet S is conveyed between the photosensitive drum 61 and transfer roller 63.
The fixing device 8 is positioned to the rear of the process cartridge 5. The fixing device 8 includes a heating roller 81, and a pressure roller 82. After a toner image has been transferred onto a sheet S, the sheet S passes through the fixing device 8, which thermally fixes the toner image to the sheet S. Once the toner image has been thermally fixed to the sheet S, the sheet S is discharged into a discharge tray 22 by pairs of conveying rollers 23 and 24.
Next, a method of recycling the developing cartridge 7 (recycling method) will be described.
Fig. 2 is a flowchart illustrating steps in the recycling method of this embodiment. In S1 the operator first collects a used developing cartridge 7 (collection step S1). At this time, toner T1 remains in the casing 75 of the collected developing cartridge 7, as illustrated in Fig. 4A.
After completing the collection step S1, in S2 the operator removes the cap CP from the collected developing cartridge 7 and discharges the toner T1 remaining in the casing 75 through the fill hole 75A (discharge step S2), as illustrated in Figs. 2 and 4B. In the discharge step S2, since the developing cartridge 7 is not disassembled and the toner T1 is discharged from the casing 75 by simply turning the casing 75 over so that the fill hole 75A faces downward, some toner T1 may remain in the corners of the casing 75.
After completing the discharge step S2, in S3 the operator refills the casing 75 of the used developing cartridge 7 with new toner T2 through the fill hole 75A, as illustrated in Figs. 2 and 4C (refilling step S3). After completing the refilling step S3 and remounting the cap CP in the fill hole 75A, in S4 the operator mounts the developing cartridge 7 to a developing roller rotating device 200 illustrated in Fig. 5A (mounting step S4).
The developing roller rotating device 200 is a device that rotates the developing roller 71 for a preset first period of time (hereinafter referred to as "first time period"). The developing roller rotating device 200 includes a motor (not illustrated) that supplies a drive force to the coupling of the developing cartridge 7, and a second control unit 210. The second control unit 210 is configured of a CPU, RAM, ROM, and input and output circuits, for example.
After completing the mounting step S4, in S5 the operator stores a second charge amount indicating the electric charge amount of the new toner T2 in the memory 76 of the developing cartridge 7 (first storage step S5). The second charge amount is determined for each lot and varies among lots. As an example of a method of storing the second charge amount in the memory 76, the operator may input the second charge amount through an operation panel of the developing roller rotating device 200, and the second control unit 210 may then write this second charge amount to the memory 76.
As another method of storing the second charge amount, the operator may input the second charge amount using a special input device for writing information to the memory 76. In this case, the operator can store the second charge amount in the memory 76 prior to the mounting step S4.
After completing the first storage step S5, the operator may operate the operation panel of the developing roller rotating device 200 to input a start command into the second control unit 210 instructing the developing roller rotating device 200 to begin rotating the developing roller 71, for example. At this time, the second control unit 210 reads the first charge amount and second charge amount from the memory 76. Subsequently, in S6 the second control unit 210 sets a first time period based on the first charge amount and second charge amount (first setting step S6).
Specifically, the second control unit 210 sets the first time period based on the map illustrated in Fig. 3. That is, the second control unit 210 sets a longer first time period when the difference between the first charge amount A and second charge amount B (|A-B|) is greater than a first time period set when the difference between the first charge amount A and second charge amount B (|A-B|) is smaller. The second control unit 210 also sets a longer first time period for a smaller second charge amount B than a first time period set for a greater second charge amount B.
For example, when the second charge amount B satisfies the expression 20 [µC/g] ≤ B < 30 [µC/g], the second control unit 210 sets the first time period to a value increasing in the order 120 seconds, 180 seconds, 240 seconds, 300 seconds, and 360 seconds as the difference |A-B| increases. Furthermore, when the difference |A-B| satisfies the expression 20 [µC/g] ≤ |A-B| < 30 [µC/g], the second control unit 210 sets the first time period to a value increasing in the order 60 seconds, 120 seconds, 180 seconds, 240 seconds, 300 seconds, and 360 seconds as the second charge amount B decreases.
After completing the first setting step S6, in S7 the second control unit 210 rotates the developing roller 71 for the first time period set in S6 (developing roller rotating step S7). When the developing roller rotating step S7 is performed, the old toner T1 and new toner T2 mix together. As the old toner T1 and the new toner T2 rub against each other between the developing roller 71 and supply roller 72, or between the developing roller 71 and thickness-regulating blade 73, toner whose charge amount has dropped to a level where the toner can no longer be retained on the developing roller 71 (hereinafter also referred to as "degraded toner T3") may be generated, as illustrated in Fig. 5B. Specifically, when the developing roller 71 rotates in a state where the old toner T1 and new toner T2 are mixed, toner whose charge amount gradually increases may be generated, while toner whose charge amount gradually decreases may also be generated. As a result, degraded toner T3 may be generated.
However, since the degraded toner T3 leaks out of the developing cartridge 7 as the developing roller 71 rotates, the degraded toner T3 is eliminated from the developing cartridge 7.
Here, the amount of degraded toner T3 generated increases as the difference between the first charge amount and second charge amount becomes greater, and also increases as the second charge amount becomes smaller. Therefore, a sufficient amount of degraded toner T3 can be discharged from the developing cartridge 7 by rotating the developing roller 71 for the first time period, which is set to a longer period of time when the difference between the first charge amount and second charge amount is greater than when the difference between the first charge amount and second charge amount is smaller and is set to a longer period of time when the second charge amount is smaller than when the second charge amount is greater.
The degraded toner T3 that leaks out of the developing cartridge 7 may be collected in a waste toner box (not illustrated) and may subsequently be disposed of. In the present embodiment, after completing the developing roller rotating step S7, the second control unit 210 stores recycling information indicating that the developing cartridge 7 has been recycled and new product information indicating that the developing cartridge 7 is a new product in the memory 76.
Rather than storing new product information in the memory 76 to return the developing cartridge 7 to a new state, the operator may return a new product detection mechanism used for detecting whether the developing cartridge 7 is a new product to its initial state.
After completing the developing roller rotating step S7 in Fig. 2, in S8 the operator removes the developing cartridge 7 from the developing roller rotating device 200 and inspects the quality of the developing cartridge 7 (inspection step S8). After completing the inspection step S8, in S9 the operator packages and ships the developing cartridge 7.
Next, the operations of the control unit 100 when a recycled developing cartridge 7 is mounted in the main casing 2 of the laser printer 1 as a new product will be described. The control unit 100 can execute a developing cartridge driving operation to rotate the developing roller 71 for a preset second period of time (hereinafter referred to as "second time period"). The control unit 100 executes the process in Fig. 6 when determining that a developing cartridge 7 has been mounted in the main casing 2.
In S20 of the process in Fig. 6, the control unit 100 reads the new product information from the memory 76 and determines whether the developing cartridge 7 mounted in the main casing 2 is a new product on the basis of the new product information. When the control unit 100 determines in S20 that the developing cartridge 7 is not a new product (S20: NO), the control unit 100 advances to the process of S25 described later.
When the control unit 100 determines in S20 that the developing cartridge 7 is a new product (S20: YES), in S21 the control unit 100 reads recycling information from the memory 76 and determines on the basis of this recycling information whether the developing cartridge 7 mounted in the main casing 2 is a recycled product. When the control unit 100 determines in S21 that the developing cartridge 7 is not a recycled product (S21: NO), the control unit 100 advances to the process of S24 described later.
However, when the control unit 100 determines in S21 that the developing cartridge 7 is a recycled product (S21: YES), in S22 the control unit 100 reads the first charge amount and second charge amount from the memory 76 and sets a second time period based on the first charge amount and second charge amount.
Specifically, the control unit 100 sets the second time period based on the map illustrated in Fig. 7. That is, the control unit 100 sets a longer second time period when the difference between the first charge amount A and second charge amount B (|A-B|) is greater than a second time period set when the difference between the first charge amount A and second charge amount B (|A-B|) is smaller. The control unit 100 also sets a longer second time period for a smaller second charge amount B than a second time period set for a greater second charge amount B.
For example, when the second charge amount B satisfies the expression 20 [µC/g] ≤ B < 30 [µC/g], the control unit 100 sets the second time period to a value increasing in the order 60 seconds, 90 seconds, 120 seconds, 150 seconds, and 180 seconds as the difference |A-B| increases. Furthermore, when the difference |A-B| satisfies the expression 20 [µC/g] ≤ |A-B| < 30 [µC/g], for example, the control unit 100 sets the second time period to a value increasing in the order 30 seconds, 60 seconds, 90 seconds, 120 seconds, 150 seconds, and 180 seconds as the second charge amount B decreases.
The second time period is set to a shorter period of time than the first time period. Specifically, when the expression 20 [µC/g] ≤ B < 30 [µC/g] and the expression 20 [µC/g] ≤ |A-B| < 30 [µC/g] are satisfied, the first time period is set to 240 seconds based on the map in Fig. 3 while the second time period is set to 120 seconds, which is shorter than the first time period, based on the map in Fig. 7. Values in the maps of Figs. 3 and 7 can be set through experimentation, simulation, or the like.
After setting the second time period in S22, in S23 the control unit 100 executes a developing cartridge driving operation to rotate the developing roller 71 for the second time period set in S22. When the control unit 100 executes the developing cartridge driving operation, the toner in the developing cartridge 7 rubs against itself between the developing roller 71 and supply roller 72, or between the developing roller 71 and thickness-regulating blade 73, resulting in an overall increase in the charge amount of the toner.
After the developing cartridge 7 undergoes the developing roller rotating step during recycling, the toner in the developing cartridge 7 may be mixed with toner whose charge amount is slightly lower than the proper value (hereinafter referred to as "undercharged toner"). The charge amount of undercharged toner is smaller as the difference between the first charge amount and second charge amount becomes greater and is smaller as the second charge amount becomes smaller. Hence, by rotating the developing roller 71 for a second time period, which is set to a longer period of time when the difference between the first charge amount and second charge amount is greater than when the difference between the first charge amount and second charge amount is smaller and is set to a longer period of time when the second charge amount is smaller than when the second charge amount is greater, the control unit 100 can raise the charge amount of the undercharged toner to a charge amount suitable for printing.
After rotating the developing roller in S23, in S24 the control unit 100 performs various correction operations such as density correction. After completing S24, in S25 the control unit 100 shifts into a standby state and subsequently ends the process of Fig. 6.
Next, a brief summary will be given for the sequence of steps from recycling the used developing cartridge 7 to using the recycled developing cartridge 7 in the laser printer 1 for the first time.
When recycling a used developing cartridge 7, the operator collects the used developing cartridge 7, as illustrated in Fig. 4A. The operator then removes the cap CP from the developing cartridge 7, and discard the toner T1 remaining in the developing cartridge 7 through the fill hole 75A, as illustrated in Fig. 4B.
Next, the operator refills the developing cartridge 7 with new toner T2, as illustrated in Fig. 4C. The operator then fits the cap CP into the fill hole 75A and mounts the developing cartridge 7 to the developing roller rotating device 200, as illustrated in Fig. 5A.
Next, the operator stores the second charge amount in the memory 76 by inputting the second charge amount denoting the charge amount of the new toner T2 via the operation panel of the developing roller rotating device 200. When the operator subsequently inputs a start command via the operation panel, the second control unit 210 sets a first time period based on the first charge amount and second charge amount stored in the memory 76.
Next, the second control unit 210 rotates the developing roller 71 for the first time period, as illustrated in Fig. 5B. As the developing roller 71 rotates, old toner T1 becomes mixed with new toner T2, generating toner whose charge amount gradually increases and toner whose charge amount gradually decreases. When this process generates degraded toner T3, whose charge amount has dropped to the level that the toner can no longer be retained on the developing roller 71, the degraded toner T3 is discharged from the developing cartridge 7 by the rotation of the developing roller 71.
The second control unit 210 halts the rotation of the developing roller 71 after the first time period has elapsed. By setting the first time period based on the first charge amount and second charge amount, most of the degraded toner T3 generated in the developing cartridge 7 is discharged from the developing cartridge 7 by the time the developing roller rotating step is completed. As a result, the toner remaining in the developing cartridge 7 has a charge amount that does not decrease with subsequent rotations of the developing roller 71 but rather gradually increases.
The operator then removes the developing cartridge 7 from the developing roller rotating device 200. After performing a quality inspection of the developing cartridge 7, the operator then packages and ships the developing cartridge 7.
When the user who purchased the recycled developing cartridge 7 mounts this developing cartridge 7 in the main casing 2 illustrated in Fig. 1, the control unit 100 reads the first charge amount, second charge amount, recycling information, and new product information from the memory 76. When new product information has been stored in the memory 76, the control unit 100 reaches a YES determination in S20 of Fig. 6. Subsequently, the control unit 100 reaches a YES determination in S21, sets a second time period based on the first charge amount and second charge amount in S22, and rotates the developing roller 71 for the set second time period in S23.
When the control unit 100 rotates the developing roller 71, the charge amount of toner in the developing cartridge 7 gradually increases. The control unit 100 halts the rotation of the developing roller 71 after the second time period has elapsed. By setting the second time period based on the first charge amount and second charge amount, the control unit 100 can raise the charge amount of nearly all the toner in the developing cartridge 7 to a level suitable for printing.
After performing various correction operations, the control unit 100 then shifts into the standby state.
The embodiment described above can obtain the following effects:
By setting the first time period to a longer period of time when the difference between the first charge amount and second charge amount is greater than when the difference between the first charge amount and second charge amount is smaller and to a longer period of time when the second charge amount is smaller than when the second charge amount is greater, the control unit 100 can sufficiently discharge degraded toner T3 from the developing cartridge 7 during the developing roller rotating step. This can suppress toner from leaking out of the developing cartridge 7 when the recycled developing cartridge 7 is used in the laser printer 1.
By setting the second time period to a longer period of time when the difference between the first charge amount and second charge amount is greater than when the difference between the first charge amount and second charge amount is smaller and to a longer period of time when the second charge amount is smaller than when the second charge amount is greater, the control unit 100 can raise the charge amount of toner whose charge amount is slightly lower than the proper value in the developing cartridge driving operation.

Next, a second embodiment of the present invention will be described in detail while referring to the drawings as needed. Since this embodiment partially modifies the operations of the control unit 100 and second control unit 210 according to the first embodiment described above, components and processes similar to those in the first embodiment will be designated with the same reference numerals and step numbers to avoid duplicating description.
The second embodiment differs from the first embodiment in that the first charge amount stored in the memory 76 of a developing cartridge 7 is updated to a new value each time the developing cartridge 7 is recycled and refilled with new toner.
Fig. 8 illustrates steps in a recycling method according to the second embodiment. In this recycling method, a determination step S31 and an update step S32 are performed after the mounting step S4 and before the first storage step S5. All other steps in the recycling method according to the second embodiment (S1 through S4 and S5 through S9) remain the same as those in the first embodiment.
As illustrated in Fig. 8, in the recycling method according to the second embodiment, when the developing cartridge 7 is set in the developing roller rotating device 200 in the mounting step S4, the second control unit 210 of the developing roller rotating device 200 determines whether the memory 76 stores the second charge amount, which indicates the charge amount of the toner used to refill the casing 75 of the developing cartridge 7 when the developing cartridge 7 was previously recycled and refilled (determination step S31).
This determination step S31 is performed prior to executing the first storage step S5, in which a new second charge amount indicating the charge amount of the new toner T2 used to refill the casing 75 of the developing cartridge 7 in the current recycling process is stored.
When the developing cartridge 7 is being recycled for the first time, the second control unit 75 determines that the second charge amount is not stored in the memory 76 (S31: NO). In this case, the second control unit 75 advances to the first storage step S5 without performing the update step S32.
On the other hand, when the developing cartridge 7 is undergoing the second or a subsequent recycling process, the second charge amount has already been stored in the memory 76 since the first storage step S5 of the previous recycling process. In this case, in the determination step S31 the second control unit 75 determines that the second charge amount is stored in the memory 76 (S31: YES). The second control unit 75 then overwrites the first charge amount with the stored value of the second charge amount to update the first charge amount in the memory 76 (update step S32), and advances to the first storage step S5.
Note that the update of the first charge amount may alternatively be performed after both the first time period and the second time period have been set, as described in a third embodiment.
In addition to the effects obtained in the first embodiment, the second embodiment provides the following advantages:
Since the first charge amount, which is used to set the first time period and second time period, is updated each time the developing cartridge 7 is recycled, the first charge amount stored in the memory 76 accurately reflects the charge amount of the toner T1 remaining in the developing cartridge 7 at the time of collection in the collection step S1 and after the discharge step S2. As a result, in the recycling method of the present embodiment, the first time period and second time period can be set to more appropriate lengths, thereby enhancing the effects obtained in the first embodiment.

Next, a third embodiment of the present invention will be described in detail while referring to the drawings as needed. Since this embodiment partially modifies the operations of the control unit 100 according to the first and second embodiments described above, components and processes similar to those in the first and second embodiments will be designated with the same reference numerals and step numbers to avoid duplicating description.
The third embodiment differs from the first and second embodiments in that the first charge amount stored in the memory 76 of a developing cartridge 7 is updated on the basis of a usage history of the developing cartridge 7.
The memory 76 of the developing cartridge 7 of the present embodiment stores the first charge amount, and usage history information therein. The usage history information indicates a usage history of the developing cartridge 7. The usage history information includes at least one of: a cumulative rotation number, which is the cumulative number of rotations of the developing roller 71; a cumulative dot count, which is the cumulative dot count for pixels formed using the developing cartridge 7; and a cumulative printed sheet number, which is the cumulative number of sheets printed using the developing cartridge 7.
The first charge amount indicates the electric charge amount of the toner T1 remaining in the casing 75. In the present embodiment, the first charge amount is calculated on the basis of the initial charge amount and the usage history information stored in the memory 76. Therefore, the first charge amount may be modified from the initial charge amount and updated after each image formation process using the toner in the casing 75, or the first charge amount may be modified from the initial charge amount as needed without being stored in the memory 75. In latter cases, the first charge amount stored in the memory 76 corresponds to the initial charge amount, which indicates the electric charge amount of the toner when the casing 75 was last refilled. In other words, in the present embodiment, the first charge amount may be a value calculated and updated based on at least one of: the cumulative number of rotations of the developing roller 71; the cumulative dot count for pixels formed using the developing cartridge 7; and the cumulative number of sheets printed using the developing cartridge 7.
Since the recycling method of the developing cartridge 7 in the present embodiment is the same as that of the first embodiment illustrated in Fig. 2, the description thereof is omitted.
The control unit 100 of the laser printer 1 according to the third embodiment executes the process illustrated in Fig. 9.
The process in Fig. 9 includes a new step S33, which is performed after step S22 and before step S23 in the process of Fig. 6. The remaining steps in the process of Fig. 9 (S20 through S22 and S23 through S25) are the same as those in the first and second embodiments.
When the control unit 100 makes YES determinations in S20 and S21 and sets the second time period based on the first charge amount and second charge amount stored in the memory 76 in S22, in S33 the control unit 100 overwrites the first charge amount with the second charge amount to update the first charge amount in the memory 76. After completing step S33, in S23 the control unit 100 rotates the developing roller 71 for the second time period.
Note that the control unit 100 may perform steps S33 and S23 in reverse order. In other words, the control unit 100 may update the first charge amount after completing step S23.
In addition to the effects obtained in the first and second embodiments, the third embodiment provides the following additional advantages:
Since the first charge amount, which is used to set the first time period and second time period, is updated based on the usage history of the developing cartridge 7, the updated first charge amount more accurately reflects the degree of degradation of the toner during printing. Consequently, in the recycling method of the present embodiment, the first time period and second time period can be set to more appropriate lengths, thereby more enhancing the effects obtained in the first and second embodiments.
Furthermore, in the present embodiment, the first charge amount is updated after the second time period has been set. This eliminates the need for the determination step regarding the presence of the second charge amount in the memory 76, thereby reducing the time required for updating the first charge amount.

Next, a fourth embodiment of the present invention will be described in detail while referring to the drawings as needed. Since this embodiment partially modifies the operations of the control unit 100 and second control unit 210 according to the first embodiment described above, components and processes similar to those in the first embodiment will be designated with the same reference numerals and step numbers to avoid duplicating description.
Fig. 10 illustrates steps in a recycling method according to the second embodiment. In this recycling method, a second setting step S41 and a second storage step S42 are provided in place of the first storage step S5 and the first setting step S6 of the recycling method in Fig. 2. All other steps in the recycling method according to the second embodiment (S1 through S3 and S7 through S9) are the same as those in the first embodiment.
When the operator inputs a second charge amount via the operation panel of the developing roller rotating device 200 after completing the mounting step S4, the second control unit 210 receives this second charge amount. In S41 the second control unit 210 sets a first time period and a second time period based on the second charge amount received from the operator, the first charge amount stored in the memory 76, and the maps in Figs. 3 and 7 (second setting step S41).
As in the first through third embodiments, in the second setting step S41 the second control unit 210 sets a longer first time period when the difference between the first charge amount and second charge amount is greater than a first time period set when the difference between the first charge amount and second charge amount is smaller, and sets a longer first time period when the second charge amount is smaller than a first time period set when the second charge amount is greater. Furthermore, as in the first through third embodiments, the second control unit 210 sets a longer second time period when the difference between the first charge amount and second charge amount is greater than a second time period set when the difference between the first charge amount and second charge amount is smaller and sets a longer second time period when the second charge amount is smaller than a second time period set when the second charge amount is greater.
After completing the second setting step S41, in S42 the second control unit 210 stores the second time period in the memory 76 (second storage step S42). As in the first through third embodiments, the second time period is set to a shorter period of time than the first time period.
The control unit 100 according to the second embodiment executes the process illustrated in Fig. 11.
The process in Fig. 11 includes new steps S61 and S62 in place of steps S22 and S23 in the process of Fig. 6. The remaining steps in the process of Fig. 11 (S20, S21, S24, and S25) are the same as those in the first embodiment.
When the control unit 100 reaches YES determinations in S20 and S21, in S61 the control unit 100 obtains the second time period from the memory 76. After completing step S61, in S62 the control unit 100 rotates the developing roller 71 for the second time period obtained in S61. After rotating the developing roller 71 in S62, the control unit 100 advances to the process of S24 described in the first embodiment.
In addition to the effects obtained in the first embodiment, the fourth embodiment can obtain the following effects:
In the fourth embodiment described above, the control unit 100 of the laser printer 1 need not calculate the second time period. Hence, this method reduces the time required for the control unit 100 to perform operations after a new recycled developing cartridge 7 has been mounted in the laser printer 1.

Next, a fifth embodiment of the present invention will be described in detail while referring to the drawings as needed. Since the present embodiment partially modifies the operations of the control unit 100 and second control unit 210 according to the fourth embodiment described above, components and processes similar to those in the fourth embodiment will be designated with the same reference numerals and step numbers to avoid duplicating description.
The fifth embodiment differs from the fourth embodiment in that the first charge amount stored in the memory 76 of a developing cartridge 7 is updated to a new value each time the developing cartridge 7 is recycled and refilled with new toner, as in the second embodiment.
Fig. 12 illustrates steps in a recycling method according to the fifth embodiment. In the recycling method, an update step S51 is performed after the second storage step S42 and before the developing roller rotating step S7. All other steps in the recycling method according to the fourth embodiment (S1 through S4, S41, S42 and S7 through S9) remain the same as those in the fourth embodiment.
As illustrated in Fig. 12, in the recycling method according to the fifth embodiment, after setting the first time period and second time period based on the first charge amount and second charge amount in the second setting step S41, the second control unit 210 of the developing roller rotating device 200 stores the second time period in the memory 76 of the developing cartridge 7, and advances to S51. In S51 the second control unit 210 then updates the first charge amount with the second charge amount (update step S51). The second control unit 210 subsequently performs the developing roller rotating step S7.
Note that the update step S51 may alternatively be performed prior to the second storage step S42 or after the developing roller rotating step S7.
In addition to the effects obtained in the fourth embodiment, the fifth embodiment provides the following advantages:
Since the first charge amount, which is used to set the first time period and second time period, is updated each time the developing cartridge 7 is recycled, the first charge amount stored in the memory 76 accurately reflects the charge amount of the toner T1 remaining in the developing cartridge 7 at the time of collection in the collection step S1 and after the discharge step S2. As a result, in the recycling method of the present embodiment, the first time period and second time period can be set to more appropriate lengths, thereby enhancing the effects obtained in the fourth embodiment.

Next, a sixth embodiment of the present invention will be described. The sixth embodiment differs from the fourth and fifth embodiments in that the first charge amount stored in the memory 76 of a developing cartridge 7 is updated on the basis of the usage history of the developing cartridge 7, as in the third embodiment.
The memory 76 of the developing cartridge 7 of the present embodiment stores the first charge amount, and the usage history information therein, as in the third embodiment.
The first charge amount indicates the electric charge amount of the toner T1 remaining in the casing 75, and is calculated on the basis of the initial charge amount and the usage history information stored in the memory 76, as in the third embodiment.
Since the recycling method of the developing cartridge 7 in the present embodiment is the same as that in the sixth embodiment illustrated in Fig.12, the description thereof is omitted.
In addition to the effects obtained in the fourth and fifth embodiments, the sixth embodiment provides the following additional advantages:
Since the first charge amount, which is used to set the first time period and second time period, is updated based on the usage history of the developing cartridge 7, the updated first charge amount more accurately reflects the degree of degradation of the toner during printing. Consequently, in the recycling method of the present embodiment, the first time period and second time period can be set to more appropriate lengths, thereby more enhancing the effects obtained in the fourth and fifth embodiments.
While the invention has been described in conjunction with various example structures outlined above and illustrated in the figures, various alternatives, modifications, variations, improvements, and/or substantial equivalents, whether known or that may be presently unforeseen, may become apparent to those having at least ordinary skill in the art. Accordingly, the example embodiments of the disclosure, as set forth above, are intended to be illustrative of the invention, and not limiting the invention. Various changes may be made without departing from the spirit and scope of the disclosure. Therefore, the disclosure is intended to embrace all known or later developed alternatives, modifications, variations, improvements, and/or substantial equivalents. Some specific examples of potential alternatives, modifications, or variations in the described invention are provided below, wherein like parts and components to those in the above embodiment are designated with the same reference numerals to avoid duplicating description:
In the embodiments described above, the developing roller rotating device 200 is used in the developing roller rotating step, but an image forming apparatus may be used in this developing roller rotating step, for example.
Furthermore, the control unit of the device that rotates the developing roller, such as a developing roller rotating device or an image forming apparatus, sets the first time period in the embodiments described above. However, the control unit of a device other than the device that rotates the developing roller may set the first time period instead.
The second charge amount and the second time period need not be stored in a memory. In other words, it is only necessary to store the first charge amount in a memory. In this case, the first time period can still be set based on the first charge amount and second charge amount at the time of recycling.
The first time period may be set based solely on the difference between the first charge amount and the second charge amount.
The second time period may also be set based solely on the difference between the first charge amount and the second charge amount.
While an operator performs some of the operations in the recycling methods of the embodiments described above, these operations may be performed by machines. For example, the entire series of steps may be automated or only some of the steps may be performed by machines.
The image forming apparatus is not limited to a monochrome laser printer 1 but may be another type of image forming apparatus, such as a color printer, a copier, or a multifunction peripheral.
The elements appearing in the embodiments and modifications described above may be implemented in any suitable combination.
Note that the present disclosure includes the phrases "at least one of A and B", "at least one of A, B and C", and the like as alternative expressions that mean one or more of A and B, one or more of A, B and C, and the like, respectively. More specifically, the phrase "at least one of A and B" means (A), (B) or (A and B), and the phrase "at least one of A, B and C" means (A), (B), (C), (A and B), (A and C), (B and C) or (A, B and C).

Claims

A method of recycling a developing cartridge (7), the developing cartridge (7) including: a developing roller (71); a casing (75); and a memory (76), the method comprising:
a refilling step (S3) including refilling the casing (75) with new toner (T2) after use of the developing cartridge (7); and

a developing roller rotating step (S7) including rotating the developing roller (71) for a first time period after the refilling step (S3),

wherein the first time period is set based on a difference between a first charge amount (A) and a second charge amount (B), the first charge amount (A) being stored in the memory (76) and indicating an electric charge amount of old toner (T1) accommodated in the casing (75) before the use of the developing cartridge (7), the second charge amount (B) indicating an electric charge amount of the new toner (T2) refilled in the casing (75) in the refilling step (S3), and

wherein the first time period set when the difference equals a first difference value is longer than the first time period set when the difference equals a second difference value smaller than the first difference value.
The method according to claim 1,
wherein the first time period set when the second charge amount equals a first amount value is longer than the first time period set when the second charge amount equals a second amount value greater than the first amount value.
The method according to claim 1 or 2, further comprising:
a first storage step (S5) including storing the second charge amount (B) in the memory (76).
The method according to claim 1 or 2, further comprising:
a setting step (S41) including setting a second time period based on the first charge amount and the second charge amount, the second time period indicating a time period for which an image forming apparatus executes a developing cartridge driving operation, the developing cartridge driving operation including rotating the developing roller (71); and

a second storage step (S42) including storing the second time period in the memory (76).
The method according to claim 4,
wherein, in the setting step (S41), the second time period set when the difference equals a third difference value is longer than the second time period set when the difference equals a fourth difference value smaller than the third difference value.
The method according to claim 4 or 5,
wherein, in the setting step (S41), the second time period set when the second charge amount equals a third amount value is longer than the second time period set when the second charge amount equals a fourth amount value greater than the third amount value.
The method according to any one of claims 4 to 6,
wherein, in the setting step (S41), the second time period is set to be shorter than the first time period.
The method according to any one of claims 1 to 7,
wherein the memory (76) stores therein usage history information indicating a usage history of the developing cartridge (7), and

wherein the first charge amount (A) is modified using the usage history information.
The method according to claim 8,
wherein the usage history information includes at least one of:
a cumulative number of rotations of the developing roller (71);

a cumulative dot count for pixels formed using the developing cartridge (7); and

a cumulative number of sheets printed using the developing cartridge (7).
An image forming apparatus (1) comprising:
a main casing (2) in which a recycled developing cartridge is detachably mountable, the recycled developing cartridge being the developing cartridge (7) that has been recycled according to the method according to claim 3; and

a controller (100) configured to perform:
setting (S22) a second time period based on the first charge amount and the second charge amount; and

executing (S23) a developing cartridge driving operation for the second time period set in the setting (S22), the developing cartridge driving operation including rotating the developing roller (71) of the recycled developing cartridge mounted in the main casing (2).
The image forming apparatus (1) according to claim 10,
wherein, in the setting (S22), the second time period set when the difference equals a third difference value is longer than the second time period when the difference equals a fourth difference value smaller than the third difference value.
The image forming apparatus (1) according to claim 10 or 11,
wherein, in the setting (S22), the second time period set when the second charge amount equals a third amount value is longer than the second time period set when the second charge amount equals a fourth amount value greater than the third amount value.
The image forming apparatus (1) according to any one of claims 10 to 12,
wherein, in the setting (S22), the second time period is set to be shorter than the first time period.
An image forming apparatus (1) comprising:
a main casing (2) in which a recycled developing cartridge is detachably mountable, the recycled developing cartridge being the developing cartridge (7) that has been recycled according to the method according to claim 4; and

a controller (100) configured to perform:
obtaining (S61) the second time period from the memory (76) of the recycled developing cartridge (7) mounted in the main casing (2); and

executing (S62) the developing cartridge driving operation for the second time period obtained in the obtaining (S61).
The image forming apparatus (1) according to claim 14,
wherein the second time period is shorter than the first time period.