Belt unit recycling method

Abstract

To enable determination of the need for replacement or cleaning of parts of a used belt unit without disassembling the used belt unit.SOLUTION: A belt unit recycling method is provided, comprising a rotation step, measurement step, and determination step. A belt unit comprises a transfer belt and a drive roller in contact with an inner surface of the transfer belt. The rotation step involves turning the drive roller to move the transfer belt while a first roller is in contact with an outer surface of the transfer belt. The measurement step involves measuring the speed of the outer surface of the transfer belt using a measurement device. The determination step involves determining the need for replacement of the drive roller based on the measured speed of the outer surface of the transfer belt.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a method for recycling a belt unit having a transfer belt and a drive roller that contacts the inner surface of the transfer belt. [Background technology]

[0002] Conventionally, there is known a technique for recycling toner cartridges for image forming devices (see Patent Document 1). From the viewpoint of utilizing resources sustainably, it is desirable to recycle as many parts as possible.

[0003] Furthermore, in order to prevent misregistration when color images are transferred in an overlapping manner, a method is known in which a slip measurement means is provided in the image forming apparatus to measure the slip between the belt and the drive roller (see Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 5-210304 [Patent Document 2] Japanese Patent Application Publication No. 5-281807 Summary of the Invention [Problem to be solved by the invention]

[0005] The condition of a used belt unit varies depending on the usage conditions. For example, the friction coefficient of the drive roller may decrease after a long period of use. If the friction coefficient of the drive roller decreases significantly, the belt may slip, causing problems with sheet transport.

[0006] When recycling a belt unit, disassembling every belt unit and replacing the drive roller increases the number of processes and costs. Furthermore, replacing every part results in more parts being discarded. Therefore, it is preferable to reuse used belt units that are in good condition without disassembly.

[0007] Therefore, an object of the present disclosure is to provide a belt unit recycling method that can determine the need for replacement or cleaning of belt unit parts without disassembling the used belt unit. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the present disclosure provides a belt unit recycling method including a rotating step, a measuring step, and a determining step. The belt unit includes a transfer belt and a drive roller that contacts the inner surface of the transfer belt. In the rotating step, the drive roller is rotated while the first roller is in contact with the outer surface of the transfer belt, thereby moving the transfer belt. In the measurement step, a measuring device is used to measure the speed of the outer surface of the transfer belt. In the determination step, it is determined whether the drive roller needs to be replaced based on the measured speed of the outer surface of the transfer belt.

[0009] With the first roller in contact with the outer surface of the transfer belt, the drive roller is rotated to move the transfer belt, and a measuring device is used to measure the speed of the outer surface of the transfer belt.Based on the measured speed of the outer surface of the transfer belt, it is determined whether the drive roller needs to be replaced.This makes it possible to determine the need to replace or clean parts of the belt unit without disassembling the used belt unit.

[0010] If the measured speed of the outer surface of the transfer belt is less than a first threshold, it may be determined that the drive roller needs to be replaced.

[0011] If the measured speed of the outer surface of the transfer belt is smaller than a first threshold value, it is determined that the drive roller needs to be replaced, thereby making it possible to determine that the drive roller needs to be replaced without disassembling the used belt unit.

[0012] The first threshold value is preferably smaller than the peripheral speed of the drive roller.

[0013] If the measured speed of the outer surface of the transfer belt is greater than a second threshold, it may be determined that replacement of the drive roller is not necessary.

[0014] If the measured speed of the outer surface of the transfer belt is greater than the second threshold, it is determined that replacement of the drive roller is not necessary, and it can be determined that replacement of the drive roller is not necessary without disassembling the used belt unit.

[0015] It may be determined that cleaning of the drive roller is necessary when the measured speed of the outer surface of the transfer belt is equal to or greater than a first threshold value and equal to or less than a second threshold value.

[0016] When the measured speed of the outer surface of the transfer belt is greater than or equal to a first threshold value and less than or equal to a second threshold value, it is determined that cleaning of the drive roller is necessary, thereby making it possible to determine that cleaning of the drive roller is necessary without disassembling a used belt unit.

[0017] If the measured variation in the speed of the outer surface of the transfer belt is greater than a third threshold, it may be determined that the drive roller needs to be replaced.

[0018] If the fluctuation in the speed of the outer surface of the measured transfer belt is greater than a third threshold, it is determined that the drive roller needs to be replaced, making it possible to determine that the drive roller needs to be replaced without disassembling the used belt unit.

[0019] If the measured fluctuation in the speed of the outer surface of the transfer belt is equal to or less than a third threshold, it may be determined that replacement of the drive roller is not necessary.

[0020] If the measured fluctuation in the speed of the outer surface of the transfer belt is less than a third threshold, it is determined that replacement of the drive roller is not necessary, and it can be determined that replacement of the drive roller is not necessary without disassembling the used belt unit.

[0021] The first roller may be rotated in a rotation direction such that the movement direction of the outer circumferential surface is opposite to the movement direction of the portion of the transfer belt that comes into contact with the first roller.

[0022] By rotating the first roller in a direction in which the movement direction of the outer surface is opposite to the movement direction of the part of the transfer belt that contacts the first roller, a large load can be applied to the transfer belt when measuring the speed of the outer surface of the transfer belt.

[0023] The belt unit may further include a backup roller that sandwiches the transfer belt between itself and the first roller.

[0024] The first roller is a belt cleaning roller provided in an image forming apparatus in which the belt unit is used, When measuring the speed of the outer surface of the transfer belt, the first roller may be rotated at a rotational speed greater than the rotational speed of the belt cleaning roller driven by the image forming apparatus.

[0025] Resistance may be applied to the rotation of the first roller.

[0026] When measuring the speed of the outer surface of the transfer belt, a second roller may be brought into contact with the outer surface of the transfer belt.

[0027] The second roller may be rotated in a rotation direction in which the movement direction of the outer circumferential surface is the same as the movement direction of the portion of the transfer belt that contacts the second roller, and at a peripheral speed that is slower than the peripheral speed of the drive roller.

[0028] Resistance may be applied to the rotation of the second roller.

[0029] The measuring device may have a third roller that contacts and follows the transfer belt, and calculate the speed of the outer surface of the transfer belt from the rotation speed of the third roller.

[0030] The measuring device may optically detect the speed of the outer surface of the transfer belt. [Effects of the Invention]

[0031] According to the present disclosure, it is possible to determine the need for replacement or cleaning of parts of a used belt unit without disassembling the belt unit. [Brief explanation of the drawings]

[0032] [Figure 1] FIG. 1 is a cross-sectional view illustrating an example of an image forming apparatus. [Figure 2] FIG. 2 is a perspective view showing a belt unit and an optical sensor. [Figure 3] FIG. 1 is a diagram illustrating an example of an inspection device for a belt unit. [Figure 4] 4 is a flowchart of a belt unit recycling method according to the first embodiment. [Figure 5] 10 is a flowchart of a belt unit recycling method according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0033] Next, the first embodiment of the present disclosure will be described in detail with reference to the drawings as appropriate. As shown in FIG. 1, a laser printer 1 as an example of an image forming apparatus includes a main body housing 10, a supply unit 20, an image forming unit 30, a discharge unit 60, a belt cleaner 90, and a control unit 100.

[0034] The supply unit 20 includes a supply tray 21 and a sheet supply device 22. The supply tray 21 is a tray that stores sheets S. The sheet supply device 22 transports the sheets S in the supply tray 21 toward the image forming unit 30.

[0035] The image forming section 30 includes an exposure device 40, four process cartridges 50, a belt unit 70, and a fixing device 80.

[0036] The exposure device 40 includes a plurality of LED units and exposes a photosensitive drum 51, which will be described later.

[0037] The process cartridge 50 includes a photosensitive drum 51, a charger 52, a developing roller 55, a toner storage chamber 56, etc. The process cartridge 50 includes four process cartridges 50Y, 50M, 50C, and 50K corresponding to toners of yellow, magenta, cyan, and black, respectively. The multiple process cartridges 50Y, 50M, 50C, and 50K are arranged in the order of yellow, magenta, cyan, and black from upstream to downstream in the conveyance direction of the sheet S. Hereinafter, when distinguishing between the colors yellow, magenta, cyan, and black, the reference numerals will be suffixed with Y, M, C, and K, respectively.

[0038] Each charger 52 faces the corresponding photosensitive drum 51. Each charger 52 charges the corresponding photosensitive drum 51.

[0039] Each developing roller 55 faces the corresponding photosensitive drum 51 .

[0040] The belt unit 70 includes a drive roller 71, a driven roller 72, a transfer belt 73 as an example of a belt, four transfer rollers 74, and a backup roller 75.

[0041] The driving roller 71 and the driven roller 72 are rollers that rotate the transfer belt 73. The driving roller 71 and the driven roller 72 are in contact with the inner surface of the transfer belt 73.

[0042] The transfer belt 73 is a belt that transports the sheet S between the photosensitive drums 51. The outer surface of the transfer belt 73 faces each of the photosensitive drums 51. The transfer rollers 74 sandwich the transfer belt 73 between themselves and the photosensitive drums 51.

[0043] The backup roller 75 comes into contact with the inner surface of the transfer belt 73, and sandwiches the transfer belt 73 between itself and a belt cleaning roller 91 of a belt cleaner 90, which will be described later.

[0044] The fixing device 80 includes a heating roller 81 and a pressure roller 82. The heating roller 81 includes a halogen heater 81A therein. The pressure roller 82 sandwiches the sheet S between itself and the heating roller 81.

[0045] In the image forming unit 30, first, the surface of the photosensitive drum 51 is charged by the charger 52 and then exposed by the exposure device 40. As a result, an electrostatic latent image is formed on the photosensitive drum 51. Thereafter, toner is supplied from the development roller 55 to the electrostatic latent image, thereby forming a toner image on the photosensitive drum 51. In this embodiment, the toner has, as an example, a positively charged characteristic.

[0046] Next, the sheet S supplied onto the transfer belt 73 passes between the photosensitive drum 51 and the transfer roller 74, whereby the toner image formed on the photosensitive drum 51 is transferred onto the sheet S. Then, the sheet S passes between the heating roller 81 and the pressure roller 82, whereby the toner image transferred onto the sheet S is thermally fixed.

[0047] The discharge section 60 is configured to transport the sheet S discharged from the fixing device 80 toward the outside of the main body housing 10. The discharge section 60 includes a transport roller 61 and a discharge roller 62. The sheet S discharged from the fixing device 80 is transported to the discharge roller 62 by the transport roller 61, and is discharged onto the discharge tray 11 by the discharge roller 62.

[0048] The belt cleaner 90 includes a belt cleaning roller 91 as a first roller, a collection roller 92, a scraping blade 93, and a storage unit 94. The belt cleaner 90 is configured to collect toner on the transfer belt 73 into the storage unit 94.

[0049] More specifically, the belt cleaning roller 91 comes into contact with the outer surface of the transfer belt 73 and collects toner adhering to the outer surface of the transfer belt 73. The collection roller 92 comes into contact with the belt cleaning roller 91 and collects toner on the belt cleaning roller 91. The scraping blade 93 comes into contact with the collection roller 92 and scrapes off the toner on the collection roller 92. The storage section 94 stores the toner scraped off the collection roller 92 by the scraping blade 93.

[0050] 1 and 2, the image forming unit 30 further includes an optical sensor 200. The optical sensor 200 faces the end of the transfer belt 73 on the drive roller 71 side.

[0051] The optical sensor 200 faces the outer surface of the transfer belt 73. The optical sensor 200 is a sensor that detects the position and density of a patch image P formed on the outer surface of the transfer belt 73. Here, the patch image P is an adjustment toner image used to correct toner color misregistration and density. The patch images P are formed on the transfer belt 73 as patch images PY, PM, PC, and PK corresponding to the colors yellow, magenta, cyan, and black. The patch images P are transferred from each photosensitive drum 51 to the transfer belt 73 when correcting toner color misregistration and density. When detecting the position and density of the patch image P, the control unit 100 of the laser printer 1 forms the patch image P on the outer surface of the transfer belt 73. The control unit 100 determines the position and density of the patch image P based on the detection result of the optical sensor 200.

[0052] Used belt units 70 are collected for recycling. It is desirable to reuse belt units 70 that are in good condition. However, if the belt unit 70 is used for a long period of time, the coefficient of friction of the drive roller 71 may decrease, causing slippage of the transfer belt 73. If slippage occurs between the transfer belt 73 and the drive roller 71, the drive roller 71 must be replaced or cleaned.

[0053] An inspection is performed to determine whether the drive roller 71 needs to be replaced or cleaned without disassembling the belt unit 70. Fig. 3 shows an example of an inspection device 300 that can be used to inspect the belt unit 70. The inspection device 300 has a support base 301, a photosensitive drum dummy 51D as the second roller, a speed measuring device 400, and a belt cleaner 90.

[0054] The support base 301 supports the belt unit 70 so that the drive roller 71, the driven roller 72, the four transfer rollers 74, and the backup roller 75 can rotate. The support base 301 also supports the photosensitive drum dummy 51D and the speed measuring device 400.

[0055] In this embodiment, two photosensitive drum dummies 51D are provided. The photosensitive drum dummies 51D are driven by a motor (not shown). When the belt unit 70 is attached to the inspection device 300, the photosensitive drum dummies 51D sandwich the transfer belt 73 between themselves and the transfer roller 74.

[0056] The speed measuring device 400 has a roller 401 as a third roller and a rotary encoder (not shown). The roller 401 contacts and follows the outer surface of the transfer belt 73. In other words, while the roller 401 follows the outer surface of the transfer belt 73, the speed of the outer surface of the roller 401 is the same as the speed of the outer surface of the transfer belt 73. When the belt unit 70 is attached to the inspection device 300, the roller 401 sandwiches the transfer belt 73 between itself and the transfer roller 74. The speed measuring device 400 obtains the rotational speed of the roller 401 using the rotary encoder and calculates the speed of the outer surface of the transfer belt 73 from the rotational speed of the roller 401.

[0057] The belt cleaner 90 is provided in the laser printer 1 in which the belt unit 70 is used. That is, the same belt cleaner 90 as that installed in the laser printer 1 is installed in the inspection device 300. When the belt unit 70 is installed in the inspection device 300, the belt cleaning roller 91 of the belt cleaner 90 sandwiches the transfer belt 73 between itself and the backup roller 75 of the belt unit 70. The belt cleaning roller 91 of the belt cleaner 90 is driven by a motor (not shown).

[0058] Next, a description will be given of a method for recycling the belt unit 70 using the inspection device 300. The belt unit 70 to be inspected is attached to the inspection device 300 so that the transfer belt 73 is sandwiched between the photosensitive drum dummy 51D and the transfer roller 74, between the roller 401 of the speed measuring device 400 and the transfer roller 74, and between the belt cleaning roller 91 and the backup roller 75.

[0059] The recycling method for the belt unit 70 includes a rotating step, a measuring step, and a determining step. In the rotating step, the belt cleaning roller 91 and the dummy photosensitive drum 51D are in contact with the outer surface of the transfer belt 73, and a motor (not shown) rotates the drive roller 71 to move the transfer belt 73.

[0060] At this time, the belt cleaning roller 91 rotates in a direction such that the movement direction of the outer circumferential surface is opposite to the movement direction of the portion of the transfer belt 73 that the belt cleaning roller 91 contacts. As a result, the belt cleaning roller 91 applies a relatively large load to the transfer belt 73. It is desirable to rotate the belt cleaning roller 91 at a rotational speed that is higher than the rotational speed of the belt cleaning roller 91 driven by the laser printer 1, that is, the rotational speed at which the belt cleaning roller 91 collects toner on the transfer belt 73.

[0061] Furthermore, the photosensitive drum dummy 51D rotates in a rotation direction such that the movement direction of the outer peripheral surface is the same as the movement direction of the portion of the transfer belt 73 with which the photosensitive drum dummy 51D comes into contact, and at a peripheral speed that is slower than the peripheral speed of the drive roller 71. As a result, the transfer drum dummy 51D applies a slight load to the transfer belt 73.

[0062] In the measurement step, the speed measuring device 400 measures the speed of the outer surface of the transfer belt 73. Specifically, the speed measuring device 400 obtains the rotation speed of the roller 401 that contacts and follows the transfer belt 73 using a rotary encoder (not shown), and calculates the speed of the outer surface of the transfer belt 73 from the rotation speed of the roller 401.

[0063] In other words, the speed of the outer surface of the transfer belt 73 is measured with a load applied to the transfer belt 73 by the belt cleaning roller 91 and the transfer drum dummy 51D. A load is also applied to the transfer belt 73 by the bearing of the driven roller 72. Note that the driving force of the motor (not shown) that drives the drive roller 71 during measurement is set to the same level as during normal operation of the laser printer 1.

[0064] In the determination process, whether the drive roller 71 needs to be replaced is determined based on the measured speed of the outer surface of the transfer belt 73. Specifically, if the measured speed of the outer surface of the transfer belt 73 is smaller than a first threshold, it is determined that the drive roller 71 needs to be replaced. The first threshold is set to a value smaller than the circumferential speed of the drive roller 71. This is because, if no slippage occurs, the speed of the outer surface of the transfer belt 73 is approximately the same as the circumferential speed of the drive roller 71, whereas if slippage occurs, the speed of the outer surface of the transfer belt 73 is slower than the circumferential speed of the drive roller 71. If the measured speed of the outer surface of the transfer belt 73 is greater than a second threshold, it is determined that the drive roller 71 does not need to be replaced. If the measured speed of the outer surface of the transfer belt 73 is equal to or greater than the first threshold and equal to or less than the second threshold, it is determined that the drive roller 71 needs to be cleaned. The drive roller 71 can be cleaned, for example, by pressing a rubber blade against the surface of the drive roller 71 to remove foreign matter, and then wiping the drive roller 71 with a cloth using alcohol. After cleaning the drive roller 71, the belt unit 70 is subjected to inspection again.

[0065] Next, a method for recycling the belt unit 70 according to this embodiment using the inspection device 300 will be described with reference to the flowchart of FIG.

[0066] With the belt unit 70 attached to the inspection device 300, the drive roller 71 is rotated by a motor (not shown) to move the transfer belt 73 (S1). Subsequently, the belt cleaning roller 91 and the photosensitive drum dummy 51D are rotated (S2).

[0067] After step S2, the speed of the outer surface of transfer belt 73 is measured using speed measuring device 400 (S3). Next, it is determined whether the speed of the outer surface of transfer belt 73 is less than a first threshold value (S4). If the speed of the outer surface of transfer belt 73 is less than the first threshold value, that is, if the speed of the outer surface of transfer belt 73 is slow (S4, Yes), it is considered that the coefficient of friction of drive roller 71 has decreased, and it is determined that drive roller 71 needs to be replaced (S5). If the speed of the outer surface of transfer belt 73 is equal to or greater than the first threshold value (S4, No), the process proceeds to step S6.

[0068] In step S6, it is determined whether the speed of the outer surface of transfer belt 73 is greater than a second threshold. If the speed of the outer surface of transfer belt 73 is greater than the second threshold, i.e., if the speed of the outer surface of transfer belt 73 is sufficiently fast (S6, Yes), it is determined that the coefficient of friction of drive roller 71 has not decreased, and therefore it is determined that replacement and cleaning of drive roller 71 is not necessary (S7). If the speed of the outer surface of transfer belt 73 is equal to or less than the second threshold, i.e., if the speed of the outer surface of transfer belt 73 is somewhat slow (S6, No), it is determined that the coefficient of friction of drive roller 71 has decreased somewhat but can be restored by cleaning, and therefore it is determined that cleaning of drive roller 71 is necessary (S8).

[0069] As described above, the following effects can be obtained in this embodiment.

[0070] In this embodiment, the drive roller 71 is rotated to move the transfer belt 73 while the belt cleaning roller 91 and the transfer drum dummy 51D are in contact with the outer surface of the transfer belt 73, and the speed of the outer surface of the transfer belt 73 is measured using the speed measuring device 400. Whether the drive roller 71 needs to be replaced is determined based on the measured speed of the outer surface of the transfer belt 73. This makes it possible to determine whether the drive roller 71 needs to be replaced without disassembling the used belt unit 70.

[0071] If the measured speed of the outer surface of the transfer belt 73 is smaller than a first threshold value, it is determined that the drive roller 71 needs to be replaced; if the measured speed of the outer surface of the transfer belt 73 is greater than a second threshold value, it is determined that the drive roller 71 does not need to be replaced; and if the measured speed of the outer surface of the transfer belt 73 is greater than or equal to the first threshold value and less than or equal to the second threshold value, it is determined that the drive roller 71 needs to be cleaned.This makes it possible to determine the need for replacement or cleaning of the drive roller 71 without disassembling the used belt unit 70.

[0072] When measuring the speed of the outer surface of the transfer belt 73, the belt cleaning roller 91 is rotated in a direction such that the movement direction of its outer circumferential surface is opposite to the movement direction of the portion of the transfer belt 73 with which the belt cleaning roller 91 contacts, and the transfer drum dummy 51D is rotated in a direction such that the movement direction of its outer circumferential surface is the same as the movement direction of the portion of the transfer belt 73 with which the transfer drum dummy 51D contacts, and at a peripheral speed slower than the peripheral speed of the drive roller 71. In other words, the load on the transfer belt 73 during measurement is greater than the load on the transfer belt 73 during normal operation of the laser printer 1, and therefore the slip resistance of the recycled belt unit 70 can be guaranteed.

[0073] Next, a second embodiment of the present disclosure will be described in detail. This embodiment is a method for recycling a belt unit 70 using the inspection device 300 according to the first embodiment, and includes the same rotation process and measurement process as the first embodiment. The same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0074] In the determination process of this embodiment, if the measured fluctuation in the speed of the outer surface of the transfer belt 73 is greater than a third threshold, it is determined that the drive roller 71 needs to be replaced. Also, if the measured fluctuation in the speed of the outer surface of the transfer belt 73 is equal to or less than the third threshold, it is determined that the drive roller 71 does not need to be replaced. When slippage occurs in the transfer belt 73, the fluctuation in the speed of the outer surface of the transfer belt 73 becomes large. The fluctuation in the speed of the outer surface of the transfer belt 73 can be, for example, the difference between the maximum and minimum speed values ​​within a predetermined period.

[0075] Next, a method for recycling the belt unit 70 according to this embodiment using the inspection device 300 will be described with reference to the flowchart of FIG.

[0076] With the belt unit 70 attached to the inspection device 300, the drive roller 71 is rotated by a motor (not shown) to move the transfer belt 73 (S11). Subsequently, the belt cleaning roller 91 and the photosensitive drum dummy 51D are rotated (S12).

[0077] After step S12, the speed of the outer surface of transfer belt 73 is measured using speed measuring device 400 (S13). Next, it is determined whether the speed fluctuation of the outer surface of transfer belt 73 is greater than a third threshold (S14). If the speed fluctuation of the outer surface of transfer belt 73 is greater than the third threshold, i.e., if the speed fluctuation of the outer surface of transfer belt 73 is large (S14, Yes), it is considered that the coefficient of friction of drive roller 71 has decreased, and it is determined that drive roller 71 needs to be replaced (S15). If the speed fluctuation of the outer surface of transfer belt 73 is equal to or less than the third threshold, i.e., if the speed fluctuation of the outer surface of transfer belt 73 is small (S14, No), it is considered that the coefficient of friction of drive roller 71 has not decreased, and it is determined that drive roller 71 does not need to be replaced (step S16).

[0078] As described above, the following effects can be obtained in this embodiment.

[0079] If the measured fluctuation in speed of the outer surface of the transfer belt 73 is greater than a third threshold, it is determined that the drive roller 71 needs to be replaced, and if the measured fluctuation in speed of the outer surface of the transfer belt 73 is equal to or less than the third threshold, it is determined that the drive roller 71 does not need to be replaced.This makes it possible to determine the need to replace the drive roller 71 without disassembling the used belt unit 70.

[0080] The present disclosure is not limited to the embodiments, and can be used in various forms as exemplified below.

[0081] In the above-described embodiment, the belt cleaning roller 91 is driven by a motor, but the belt cleaning roller 91 may not be rotated by a motor, and a load may be applied to the transfer belt 73 by applying resistance to the rotation of the belt cleaning roller 91. For example, a friction member may be pressed against a gear that rotates the belt cleaning roller 91.

[0082] In the above-described embodiment, the photosensitive drum dummy 51D is driven by a motor, but the photosensitive drum dummy 51D may not be rotated by a motor, and a load may be applied to the transfer belt 73 by applying resistance to the rotation of the photosensitive drum dummy 51D. For example, a friction member may be pressed against a gear that rotates the photosensitive drum dummy 51D.

[0083] In the above embodiment, two photosensitive drum dummies 51D are provided in the inspection device 300, but the number of photosensitive drum dummies 51D may be one or three or more. Also, in the above embodiment, two identical photosensitive drum dummies 51D are provided, but the photosensitive drum dummies 51D may have different diameters, materials, etc. Instead of providing the inspection device 300 with a photosensitive drum dummy 51D, a photosensitive drum identical to the photosensitive drum 51 attached to the laser printer 1 may be attached to the inspection device 300.

[0084] In the above-described embodiment, the belt cleaning roller 91 is rotated in a direction in which the movement direction of its outer circumferential surface is opposite to the movement direction of the transfer belt 73, and the photosensitive drum dummy 51D is rotated in a direction in which the movement direction of its outer circumferential surface is the same as the movement direction of the portion of the transfer belt 73 with which the photosensitive drum dummy 51D makes contact, and at a circumferential speed slower than the circumferential speed of the drive roller 71. However, as long as the load applied to the transfer belt 73 by the bearings of the belt cleaning roller 91, the photosensitive drum dummy 51D, and the driven roller 72 is sufficiently large, the rotations of the belt cleaning roller 91 and the photosensitive drum dummy 51D may be set in any way.

[0085] In the above embodiment, a load is applied to the transfer belt 73 by both the belt cleaning roller 91 and the dummy photosensitive drum 51D, but a load may be applied to the transfer belt 73 by using only the belt cleaning roller 91.

[0086] In the above-described embodiment, the measuring device is of a contact type, but the measuring device may also be one that optically detects the speed of the outer surface of the transfer belt 73. For example, a laser Doppler velocimeter can be used.

[0087] The elements described in the above-described embodiment and modified examples may be implemented in any combination. [Explanation of symbols]

[0088] 70 Belt unit 71 Drive roller 73 Transfer belt 91 Belt cleaning roller 400 speed measuring device

Claims

1. A method for recycling a belt unit having a transfer belt and a drive roller that contacts the inner surface of the transfer belt, comprising: a rotating step of rotating the drive roller to move the transfer belt while the first roller is in contact with the outer surface of the transfer belt; a measuring step of measuring the speed of the outer surface of the transfer belt using a measuring device; and a determining step of determining whether the drive roller needs to be replaced based on the measured speed of the outer surface of the transfer belt.

2. 2. The method for recycling a belt unit according to claim 1, wherein it is determined that the drive roller needs to be replaced when the measured speed of the outer surface of the transfer belt is smaller than a first threshold value.

3. 3. The method for recycling a belt unit according to claim 2, wherein the first threshold value is smaller than the peripheral speed of the drive roller.

4. 3. The method for recycling a belt unit according to claim 2, wherein it is determined that replacement of the drive roller is unnecessary when the measured speed of the outer surface of the transfer belt is greater than a second threshold value.

5. 5. The method for recycling a belt unit according to claim 4, wherein it is determined that cleaning of the drive roller is necessary when the measured speed of the outer surface of the transfer belt is equal to or greater than a first threshold value and equal to or less than a second threshold value.

6. 2. The method for recycling a belt unit according to claim 1, further comprising determining that the drive roller needs to be replaced when the measured fluctuation in speed of the outer surface of the transfer belt is greater than a third threshold value.

7. 7. The method for recycling a belt unit according to claim 6, wherein it is determined that replacement of the drive roller is unnecessary when the measured fluctuation in speed of the outer surface of the transfer belt is equal to or less than a third threshold value.

8. 8. The method for recycling a belt unit according to claim 1, wherein the first roller is rotated in a direction in which the direction of movement of the outer peripheral surface is opposite to the direction of movement of the portion of the transfer belt with which the first roller contacts.

9. 9. The method for recycling a belt unit according to claim 8, wherein the belt unit further comprises a backup roller that sandwiches the transfer belt between the first roller and the backup roller.

10. The first roller is a belt cleaning roller provided in an image forming apparatus in which the belt unit is used, 9. The method for recycling a belt unit according to claim 8, wherein when measuring the speed of the outer surface of the transfer belt, the first roller is rotated at a rotational speed higher than the rotational speed of a belt cleaning roller driven by the image forming apparatus.

11. 8. The method for recycling a belt unit according to claim 1, further comprising the step of applying resistance to the rotation of the first roller.

12. 8. The method for recycling a belt unit according to claim 1, wherein a second roller is brought into contact with the outer surface of the transfer belt when measuring the speed of the outer surface of the transfer belt.

13. The method for recycling a belt unit according to claim 12, wherein the second roller is rotated in a direction in which the direction of movement of its outer circumferential surface is the same as the direction of movement of the portion of the transfer belt that contacts the second roller, and at a peripheral speed that is slower than the peripheral speed of the drive roller.

14. 13. The method for recycling a belt unit according to claim 12, further comprising the step of applying resistance to the rotation of the second roller.

15. 2. The method for recycling a belt unit according to claim 1, wherein the measuring device has a third roller that contacts and follows the transfer belt, and calculates the speed of the outer surface of the transfer belt from the rotation speed of the third roller.

16. 2. The method for recycling a belt unit according to claim 1, wherein the measuring device optically detects the speed of the outer surface of the transfer belt.

Images