Image forming apparatus

Abstract

Provided is an image forming apparatus capable of determining degradation of a transfer belt even if the transfer belt is replaced. A control unit of an image forming apparatus executes: a light amount correction process for correcting an emission light amount, which is the light amount of light emitted from a light-emitting element of a sensor, such that the light amount of reflected light received by a light-receiving element of the sensor from a portion on the surface of a transfer belt where a toner image is not formed, becomes a predetermined value; carrying out concentration correction treatment; a first update process for updating an accumulated value stored in a transfer memory by adding an accumulated value of the change amount stored in the transfer memory to the change amount of the output light amount corrected by the light amount correction process with respect to the output light amount corrected by the previous light amount correction process stored in the transfer memory of the transfer unit; a second update process for updating the amount of emitted light stored in the transfer memory to the amount of emitted light corrected by the latest light amount correction process; and a first determination process for determining that the transfer belt is deteriorated when the accumulated value is equal to or greater than a first threshold value.

Description

Technical Field

[0001] The present invention relates to an image forming device. Background Art

[0002] Conventionally, as an image forming apparatus, there is known an apparatus that adjusts the output value of an optical sensor so that the amount of reflected light from the ground portion of a transfer belt is constant when an adjustment mode such as adjusting the density of an image is executed, and obtains the adjusted output value (Patent Document 1). In this technology, it is determined whether the ratio of the adjusted output value to the initial output value stored in a memory of the apparatus body exceeds a threshold value for executing a removal mode for removing a coating film formed on the surface of the transfer belt, and the removal mode is executed if the ratio exceeds the threshold value.

[0003] Patent Literature

[0004] Patent Document 1: Japanese Patent Application Publication No. 2016-020970

[0005] Technical problem to be solved by the invention

[0006] However, the transfer belt may be degraded to such an extent that the final surface state cannot be restored even after the coating is removed. Therefore, in an image forming apparatus, it is desirable to be able to replace the transfer belt regardless of whether or not the image forming apparatus has a function of removing the coating. Furthermore, in an image forming apparatus that can replace the transfer belt, it is desirable to be able to determine the deterioration of the transfer belt even after the transfer belt is replaced. Summary of the invention

[0007] Technical means for solving technical problems

[0008] The image forming apparatus includes an apparatus main body, a transfer unit, a sensor, and a control unit.

[0009] The transfer unit is detachable from the apparatus body and includes a transfer memory and an endless transfer belt.

[0010] The sensor includes a light emitting element that emits light and a light receiving element that can receive reflected light emitted from the light emitting element.

[0011] The control unit executes a light amount correction process, a density correction process, a first update process, a second update process, and a first determination process.

[0012] The light amount correction process is a process for correcting the amount of emitted light emitted from the light emitting element so that the amount of reflected light received by the light receiving element from a portion of the surface of the transfer belt where no toner image is formed becomes a predetermined value. The emitted light amount is the amount of light emitted from the light emitting element.

[0013] The concentration correction processing is a processing for correcting the concentration of the toner image formed on the sheet based on the reflected light from the part of the surface of the transfer belt where the toner image for concentration correction is formed and from the part of the surface of the transfer belt where the toner image is not formed, which is received by the light receiving element after the light whose emitted light amount is corrected by the light amount correction processing is emitted from the light emitting element to the surface of the transfer belt.

[0014] The first updating process is a process of updating the accumulated value stored in the transfer memory by adding the accumulated value of the change in the emission light amount corrected by the light amount correction process relative to the emission light amount corrected by the previous light amount correction process stored in the transfer memory to the accumulated value of the change in the transfer memory.

[0015] The second updating process is a process of updating the emission light amount stored in the transfer memory to the emission light amount corrected by the most recent light amount correction process.

[0016] The first determination process is a process of determining that the transfer belt has deteriorated when the cumulative value is equal to or greater than a first threshold value.

[0017] By storing the cumulative value for determining whether the transfer belt has deteriorated in the transfer memory, it is possible to determine the deterioration of the transfer belt even when the transfer belt is replaced.

[0018] The control unit may execute the second determination process to determine that the transfer belt has deteriorated when the emission light amount is equal to or greater than the second threshold value, regardless of the cumulative value.

[0019] By executing the second determination process, it is possible to determine the deterioration of the transfer belt based on the amount of emitted light.

[0020] The control unit may be configured such that, when it is determined that the transfer unit is attached to the apparatus body, the control unit reads the accumulated value from the transfer memory and executes the first determination process.

[0021] By reading the cumulative value from the transfer memory when the transfer unit is mounted on the apparatus body and executing the first determination process, it is possible to determine the deterioration of the transfer belt based on the cumulative value stored in the transfer memory.

[0022] The control unit may be configured such that, when it is determined that the transfer unit is attached to the apparatus body, the control unit reads the amount of emitted light from the transfer memory and executes the second determination process.

[0023] By reading the emission light amount from the transfer memory when the transfer unit is mounted on the apparatus body and executing the second determination process, it is possible to determine the deterioration of the transfer belt based on the emission light amount stored in the transfer memory.

[0024] The control unit may be configured to execute the light amount correction process when determining that the number of printed sheets is the predetermined number of sheets.

[0025] By executing the light amount correction process when the number of printed sheets is a predetermined number of sheets, it is possible to correct the emitted light amount to an appropriate amount corresponding to the number of printed sheets.

[0026] The control unit may be configured to execute the light amount correction process when it is determined that the installation environment of the image forming apparatus has changed.

[0027] By executing the light amount correction process when the installation environment of the image forming apparatus changes, it is possible to correct the emission light amount to an appropriate amount corresponding to the installation environment of the image forming apparatus.

[0028] The control unit may be configured such that, when the temperature changes by a predetermined amount or more within a predetermined time, the control unit determines that the installation environment of the image forming apparatus has changed.

[0029] The control unit may be configured such that, when the humidity changes by a predetermined amount or more within a predetermined time, the control unit determines that the installation environment of the image forming apparatus has changed.

[0030] The control unit may be configured to execute the light amount correction process when it is determined that the transfer unit has been replaced.

[0031] By executing the light amount correction process when the transfer unit is replaced, it is possible to correct the emission light amount to an appropriate amount corresponding to the replaced transfer belt.

[0032] The control unit may be configured to store a flag in the transfer memory when determining that the transfer belt has deteriorated.

[0033] By storing the flag in the transfer memory, it is possible to determine whether the transfer unit can be reused when the flag is not stored in the transfer memory, or cannot be reused when the flag is stored in the transfer memory.

[0034] The following configuration may be adopted: when the flag is stored in the transfer memory, the control unit executes a notification process to cause a notification device to notify a message urging replacement of the transfer unit, the notification device being a device for notifying the user of information.

[0035] By executing the notification process, it is possible to notify the replacement time of the transfer belt.

[0036] The following configuration may be adopted: when it is determined that the transfer belt has deteriorated, the control unit executes a notification process for causing a notification device that notifies a user of information to notify a message urging replacement of the transfer unit.

[0037] By executing the notification process, it is possible to notify the replacement time of the transfer belt.

[0038] As an example, the second threshold value is the maximum value of the amount of light that can be emitted from the light emitting element.

[0039] Effects of the Invention

[0040] Even if the transfer belt is replaced, deterioration of the transfer belt can be determined. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a cross-sectional view showing the image forming apparatus.

[0042] Figure 2 It is a perspective view showing a transfer unit, an optical sensor, and a registration sensor.

[0043] Figure 3 It is a cross-sectional view showing an optical sensor.

[0044] Figure 4 It is a block diagram showing a structure related to control.

[0045] Figure 5 This is a flowchart showing the operation of the control section, and shows processing when it is determined that the transfer unit is attached to the apparatus main body.

[0046] Figure 6 This is a flowchart showing conditions for executing the light amount correction process and the density correction process.

[0047] Figure 7 : is a flowchart showing the processing after the light amount correction processing is executed.

[0048] Figure 8 : is a flowchart showing the life determination process.

[0049] Explanation of symbols

[0050] 1 Image forming device

[0051] 10 Device body

[0052] 70 transfer unit

[0053] 73 transfer belt

[0054] 75 transfer memory

[0055] 100 Optical Sensor

[0056] 120 Light emitting element

[0057] 130 first light receiving element

[0058] 140 second light receiving element

[0059] 200 Control Department

[0060] P plaque. DETAILED DESCRIPTION

[0061] Next, an embodiment will be described.

[0062] like Figure 1 As shown, the image forming apparatus 1 is a color printer, and includes an apparatus body 10 , a cover 11 , a sheet feeding unit 20 , an image forming unit 30 , a sheet discharging unit 90 , and a control unit 200 .

[0063] The device body 10 has an opening 10A. The cover 11 opens and closes the opening 10A. The cover 11 can move between a closed position for closing the opening 10A and an open position for opening the opening 10A. Specifically, the cover 11 can rotate between the closed position and the open position.

[0064] The sheet supply unit 20 includes a sheet tray 21 and a supply mechanism 22 . The sheet tray 21 is a tray for storing sheets S. The supply mechanism 22 supplies the sheets S in the sheet tray 21 toward the image forming unit 30 .

[0065] The image forming section 30 includes four exposure units 40 , four process units 50 , a transfer unit 70 , and a fixing unit 80 .

[0066] The exposure unit 40 has a plurality of LEDs. The exposure unit 40 exposes the photosensitive drum 51. The exposure unit 40 is held by the cover 11.

[0067] The process unit 50 includes a photosensitive drum 51, a charger 52, a developing roller 53, a toner storage unit 54, etc. The process unit 50 includes a process unit 50Y storing yellow toner, a process unit 50M storing magenta toner, a process unit 50C storing cyan toner, and a process unit 50K storing black toner.

[0068] The process units 50Y, 50M, 50C, and 50K are arranged in order from upstream to downstream in the conveyance direction of the sheet S. The process units 50 are detachable from the apparatus body 10. Specifically, the transfer unit 70 is detachable from the apparatus body 10 with the cover 11 open.

[0069] The transfer unit 70 includes a driving roller 71, a driven roller 72, a transfer belt 73, and four transfer rollers 74. The driving roller 71 is a roller that rotates the transfer belt 73. The transfer belt 73 is stretched between the driving roller 71 and the driven roller 72. The transfer belt 73 is an endless belt that conveys the sheet S between the photosensitive drum 51. The outer peripheral surface of the transfer belt 73 is in contact with the photosensitive drum 51. The transfer roller 74 sandwiches the transfer belt 73 between the photosensitive drum 51.

[0070] The transfer unit 70 is detachable from the apparatus main body 10. In other words, the transfer unit 70 is replaceable. The transfer unit 70 is detachable from the apparatus main body 10 in a state where the cover 11 is opened and the process unit 50 is removed.

[0071] The fixing unit 80 includes a heating roller 81 and a pressure roller 82. The heating roller 81 includes a heater 81A inside. The pressure roller 82 sandwiches the sheet S with the heating roller 81.

[0072] The image forming unit 30 charges the surface of the photosensitive drum 51 by the charger 52, and then exposes the surface by the exposure unit 40. Thus, an electrostatic latent image is formed on the photosensitive drum 51. Thereafter, the image forming unit 30 supplies toner to the photosensitive drum 51 from the developing roller 53, thereby forming a toner image on the photosensitive drum 51.

[0073] Next, the image forming unit 30 conveys the sheet S fed by the feeding mechanism 22 onto the transfer belt 73 between the photosensitive drum 51 and the transfer roller 74, thereby transferring the toner image on the photosensitive drum 51 onto the sheet S. Then, the image forming unit 30 conveys the sheet S between the heating roller 81 and the pressure roller 82, thereby fixing the toner image transferred onto the sheet S, and forming an image on the sheet S.

[0074] The sheet discharge unit 90 conveys the sheet S conveyed from the image forming unit 30 toward the outside of the apparatus body 10. The sheet discharge unit 90 includes a conveying roller 91 and a discharge roller 92. The sheet discharge unit 90 conveys the sheet S conveyed from the image forming unit 30 toward the discharge roller 92 via the conveying roller 91, and discharges the sheet S onto the discharge tray 12 via the discharge roller 92.

[0075] like Figure 2 As shown, the image forming apparatus 1 further includes an optical sensor 100 and a registration sensor RS as sensors. The optical sensor 100 and the registration sensor RS are arranged to face the end of the transfer belt 73 close to the driving roller 71 .

[0076] The registration sensor RS is a sensor for detecting the position of the patch P formed on the surface of the transfer belt 73. The patch P is a toner image for density correction for correcting the density of the toner image of each color formed on the sheet S. In addition, the patch P is also a toner image for position correction for correcting the position (color deviation) of the toner image of each color formed on the sheet S. The patch P is formed on the surface of the transfer belt 73 as patches PY, PM, PC, PK corresponding to the colors yellow, magenta, cyan, and black. The patch P is transferred from the photosensitive drum 51 of each color to the surface of the transfer belt 73 when density correction or the like is performed.

[0077] The positioning sensor RS includes a light emitting element and a light receiving element. The light emitting element is an element that emits light, and the light receiving element is an element that can receive reflected light of the light emitted from the light emitting element.

[0078] The optical sensor 100 is a sensor for detecting the density and position of the patch P formed on the surface of the transfer belt 73. Figure 3 As shown, the optical sensor 100 includes a substrate 110 , a light emitting element 120 , a first light receiving element 130 and a second light receiving element 140 as light receiving elements, a lens 150 , and a holder 160 .

[0079] The light emitting element 120, the first light receiving element 130, and the second light receiving element 140 are located on the substrate 110. The light emitting element 120 is an element that emits light. The light emitting element 120 is, for example, an LED.

[0080] The first light receiving element 130 and the second light receiving element 140 are elements capable of receiving reflected light of the light emitted from the light emitting element 120. The first light receiving element 130 and the second light receiving element 140 are photodiodes sensitive to the wavelength of the light emitted from the light emitting element 120, for example.

[0081] The first light receiving element 130 is arranged at a position where the regular reflection component of the light reflected by the patch P is incident. Specifically, the first light receiving element 130 is arranged at a position where the light having the same incident angle and reflection angle with respect to the patch P among the light irradiated from the light emitting element 120 to the patch P is incident. Thus, the first light receiving element 130 receives the regular reflection component of the light of the light emitting element 120 reflected by the patch P.

[0082] The second light receiving element 140 is arranged at a position where the diffuse reflection component of the light reflected by the patch P is incident. Specifically, the second light receiving element 140 is arranged at a position where the light component other than the regular reflection component of the light irradiated from the light emitting element 120 to the patch P is incident. Thus, the second light receiving element 140 receives the diffuse reflection component of the light of the light emitting element 120 reflected by the patch P.

[0083] The lens 150 is a lens through which light emitted from the light emitting element 120 passes. The lens 150 bends the light emitted from the light emitting element 120 toward the patch P.

[0084] The holder 160 is a member for holding the substrate 110. The holder 160 is made of, for example, resin. The holder 160 is attached to the substrate 110 so as to cover the light emitting element 120, the first light receiving element 130, and the second light receiving element 140.

[0085] like Figure 4As shown, the transfer unit 70 further includes a transfer memory 75. The transfer memory 75 is a memory that stores information related to the transfer unit 70, such as unique identification information such as a serial number, information for determining deterioration of the transfer belt 73, etc. As an example, the transfer memory 75 is an IC chip.

[0086] The control unit 200 includes a CPU, a RAM, a ROM, an input / output circuit, etc. The control unit 200 performs control by performing calculations based on programs and data stored in the ROM, etc. The control unit 200 can read information from the transfer memory 75 of the transfer unit 70 installed in the device body 10, or write information to the transfer memory 75.

[0087] The control unit 200 performs light amount correction processing, density correction processing, first update processing, second update processing, first determination processing, second determination processing, flag storage processing, and notification processing. Here, the reflected light received by the light receiving elements 130 and 140 from the portion of the surface of the transfer belt 73 where the toner image including the patch P is not formed is referred to as "belt reflected light". In addition, the reflected light received by the light receiving elements 130 and 140 from the portion of the surface of the transfer belt 73 where the patch P is formed is referred to as "patch reflected light".

[0088] The light amount correction process is a process for correcting the emission light amount LO, which is the light amount of light emitted from the light emitting element 120. The control unit 200 corrects the emission light amount LO of the light emitting element 120 so that the light amount of the belt reflected light becomes a specified value. Specifically, the control unit 200 emits light of the emission light amount LOA stored in the transfer memory 75 from the light emitting element 120 to the surface of the transfer belt 73, and detects the belt reflected light through the first light receiving element 130. Then, the control unit 200 calculates the emission light amount LOB so that the light amount of the detected belt reflected light becomes a specified value, and uses the calculated emission light amount LOB as the emission light amount LO of the light emitted by the light emitting element 120.

[0089] The control unit 200 executes the light amount correction process when it is determined that the number of printed sheets is the predetermined number of sheets. In other words, the control unit 200 executes the light amount correction process every time the predetermined number of sheets S are printed.

[0090] In addition, when it is determined that the installation environment of the image forming apparatus 1 has changed, the control unit 200 performs light amount correction processing. Specifically, in the embodiment, the image forming apparatus 1 further includes a temperature and humidity sensor 210. The temperature and humidity sensor 210 is a sensor for detecting temperature and humidity. The temperature and humidity sensor 210 can detect the temperature and humidity inside the apparatus body 10, and can also detect the temperature and humidity outside the apparatus body 10.

[0091] When the detected temperature detected by the temperature and humidity sensor 210 changes by a predetermined amount or more within a predetermined time, the control unit 200 determines that the installation environment of the image forming apparatus 1 has changed. As an example, when the detected temperature T rises to a temperature threshold value Tth1 or more within a predetermined time TM1, the control unit 200 determines that the installation environment of the image forming apparatus 1 has changed, and performs the light amount correction process.

[0092] In addition, when the detected temperature T drops below the temperature threshold value Tth2 within the specified time TM2, the control unit 200 determines that the installation environment of the image forming apparatus 1 has changed, and executes the light amount correction process. The specified times TM1 and TM2 may be the same or different. In addition, the temperature threshold values ​​Tth1 and Tth2 may be the same or different.

[0093] In addition, when the detected humidity detected by the temperature and humidity sensor 210 changes by a predetermined amount or more within a predetermined time, the control unit 200 determines that the installation environment of the image forming apparatus 1 has changed. As an example, when the detected humidity H rises to or above the humidity threshold value Hth1 within a predetermined time TM3, the control unit 200 determines that the installation environment of the image forming apparatus 1 has changed, and executes the light amount correction process.

[0094] In addition, when the detected humidity H drops below the humidity threshold value Hth2 within the specified time TM4, the control unit 200 determines that the installation environment of the image forming apparatus 1 has changed, and executes the light amount correction process. The specified times TM3 and TM4 may be the same or different. In addition, the humidity threshold values ​​Hth1 and Hth2 may be the same or different.

[0095] In addition, the control unit 200 executes the light amount correction process when receiving an instruction to execute the light amount correction process. As an example, the image forming apparatus 1 includes an operation panel, and the control unit 200 executes the light amount correction process when a user operates the operation panel and inputs an instruction to execute the light amount correction process.

[0096] In addition, as another example, when the user operates an external device connected to the image forming apparatus 1 and sends an instruction to execute the light amount correction process, the control unit 200 executes the light amount correction process. The external device is, for example, a personal computer, a smart phone, a tablet computer, etc. The image forming apparatus 1 and the external device may be connected in a communicative manner via a wire or wirelessly.

[0097] In addition, the control unit 200 performs the light amount correction process when it is determined that the transfer unit 70 has been replaced. In the embodiment, the control unit 200 obtains the identification information from the transfer memory 75 when it is determined that the transfer unit 70 is installed in the device body 10. As an example, the control unit 200 determines that the transfer unit 70 is installed in the device body 10 when the power of the image forming apparatus 1 is turned on or the cover 11 is closed. Then, when the obtained identification information is different from the currently held identification information, the control unit 200 determines that the transfer unit 70 has been replaced. In other words, when there is an update of the identification information, the control unit 200 determines that the transfer unit 70 has been replaced.

[0098] The density correction process is a process for correcting the density of the toner image formed on the sheet S. After executing the light amount correction process, the control unit 200 executes the density correction process using the light of the corrected emission light amount LO. The control unit 200 emits the light of the corrected emission light amount LO from the light emitting element 120 to the surface of the transfer belt 73, and corrects the density of the toner image formed on the sheet S based on the patch reflected light and the belt reflected light received by the light receiving elements 130 and 140.

[0099] As an example, the control unit 200 first transfers the patches P from the photosensitive drums 51 of each color to the surface of the transfer belt 73, and forms patches P (PY, PM, PC, PK) on the transfer belt 73. Next, the control unit 200 irradiates light from the light emitting element 120 to the surface of the transfer belt 73, and uses the first light receiving element 130 and the second light receiving element 140 to detect the belt reflected light and the patch reflected light of each color.

[0100] Specifically, the control unit 200 irradiates light from the light emitting element 120 to a portion of the surface of the transfer belt 73 where no patch P is formed, and detects the belt reflected light using the first light receiving element 130 and the second light receiving element 140. In addition, the control unit 200 irradiates light from the light emitting element 120 to a portion of the surface of the transfer belt 73 where the patch P is formed, and detects the patch reflected light of each color using the first light receiving element 130 and the second light receiving element 140.

[0101] Next, the control unit 200 calculates the measured intensity ΔB of the band reflected light and the measured intensity ΔP of the patch reflected light of each color. Specifically, the control unit 200 calculates the measured intensity ΔB of the band reflected light and the measured intensity ΔP of the patch reflected light of each color based on the following formulas (1) and (2).

[0102] ΔB=B1×Gsp-B2···(1)

[0103] ΔP=P1×Gsp-P2···(2)

[0104] Here, B1 is the intensity of the regular reflection component of the reflected light received by the first light receiving element 130, and B2 is the intensity of the diffuse reflection component of the reflected light received by the second light receiving element 140. P1 is the intensity of the regular reflection component of the spot reflected light received by the first light receiving element 130, and P2 is the intensity of the diffuse reflection component of the spot reflected light received by the second light receiving element 140. Gsp is a correction coefficient for the value of the measured intensity of the regular reflection component.

[0105] Then, the control unit 200 compares the measured intensity ΔB of the band reflected light with the measured intensity ΔP of the patch reflected light, and determines the parameter value for correcting the density of the toner image. Specifically, the control unit 200 calculates the ratio ΔP / ΔB of the measured intensity ΔB of the band reflected light and the measured intensity ΔP of the patch reflected light. Then, the control unit 200 determines the parameter value for correcting the density of the toner image based on the calculated ratio ΔP / ΔB and a pre-set density correction table. The control unit 200 determines the parameter value for each color.

[0106] The first update process is a process for updating the cumulative value VC stored in the transfer memory 75. The cumulative value VC is a cumulative value of the amount of change of the emitted light amount LOB corrected by the light amount correction process relative to the emitted light amount LOA corrected by the previous light amount correction process. Specifically, the cumulative value VC is a cumulative value of the value obtained by subtracting the emitted light amount LOA corrected by the previous light amount correction process from the emitted light amount LOB corrected by the light amount correction process. The emitted light amount LOA and the cumulative value VC are stored in the transfer memory 75.

[0107] The control unit 200 adds the cumulative value VC stored in the transfer memory 75 to the value obtained by subtracting the emission light amount LOA corrected by the previous light amount correction process from the emission light amount LOB corrected by the light amount correction process, and updates the cumulative value VC stored in the transfer memory 75. The control unit 200 updates the cumulative value VC (previous value) stored in the transfer memory 75 to the newly calculated cumulative value VC (this time value).

[0108] The second update process is a process for updating the emission light amount LOA stored in the transfer memory 75. The control unit 200 updates the emission light amount LOA stored in the transfer memory 75 to the emission light amount LOB corrected by the most recent light amount correction process. In other words, the control unit 200 replaces the emission light amount LOA stored in the transfer memory 75 with the emission light amount LOB corrected by the most recent light amount correction process and stores it in the transfer memory 75.

[0109] The first determination process and the second determination process are processes for determining the deterioration of the transfer belt 73 .

[0110] In the first determination process, the control unit 200 determines that the transfer belt 73 is deteriorated when the cumulative value VC is greater than or equal to the first threshold value VCth. The control unit 200 executes the first determination process when the cumulative value VC is updated. In addition, when the control unit 200 determines that the transfer unit 70 is mounted on the device body 10, the control unit 200 reads the cumulative value VC from the transfer memory 75 and executes the first determination process.

[0111] In the second determination process, the control unit 200 determines that the transfer belt 73 is degraded regardless of the accumulated value VC when the emitted light amount LOA is greater than the second threshold value LOth. In the embodiment, the second threshold value LOth is the maximum value of the light amount of light that can be emitted from the light emitting element 120. If the emitted light amount LOA exceeds the maximum value (maximum light amount value) of the light amount of light that can be emitted from the light emitting element 120, the light amount correction process cannot be performed, and therefore the concentration correction process cannot be performed correctly. Therefore, the control unit 200 determines that the transfer belt 73 is degraded when the emitted light amount LOA exceeds the maximum light amount value.

[0112] When the emission light amount LOA is updated, the control unit 200 executes the second determination process. When the control unit 200 determines that the transfer unit 70 is attached to the apparatus body 10, the control unit 200 reads the emission light amount LOA from the transfer memory 75 and executes the second determination process.

[0113] In the embodiment, when the control unit 200 determines that the transfer belt 73 is deteriorated in the second determination process, the control unit 200 does not perform the determination of whether the cumulative value VC is equal to or greater than the first threshold value VCth.

[0114] The flag storage process is a process of storing a degradation flag as a flag in the transfer memory 75. The degradation flag is a flag indicating that the transfer belt 73 is degraded. When the control unit 200 determines that the transfer belt 73 is degraded by executing the first determination process or the second determination process, the control unit 200 executes the flag storage process to store the degradation flag in the transfer memory 75. Specifically, when the control unit 200 determines that the transfer belt 73 is degraded, it updates the degradation flag stored in the transfer memory 75 from off to on.

[0115] The notification process is a process of notifying the notification device 220 of a message urging replacement of the transfer unit 70. In the embodiment, the image forming apparatus 1 further includes the notification device 220. The notification device 220 is a device for notifying the user of information. As an example, the notification device 220 is a display provided in the apparatus body 10.

[0116] When the control unit 200 determines that the transfer belt 73 is deteriorated by executing the first determination process or the second determination process, the control unit 200 causes the notification device 220 to notify a message urging replacement of the transfer unit 70. Specifically, when the control unit 200 determines that the transfer belt 73 is deteriorated, the notification device 220 (display) displays text, such as "Replace Belt", as a message urging replacement of the transfer unit 70.

[0117] In addition, when the degradation flag is stored in the transfer memory 75, the control unit 200 causes the notification device 220 to notify a message urging replacement of the transfer unit 70. Specifically, when the transfer unit 70 is replaced and the degradation flag stored in the transfer memory 75 is turned on, the control unit 200 displays the text "Replace tape" on the notification device 220.

[0118] Next, the operation of the control unit 200 will be described.

[0119] like Figure 5 As shown, when the control unit 200 determines that the transfer unit 70 is attached to the apparatus body 10 , specifically, when the image forming apparatus 1 is powered on or the cover 11 is closed, the control unit 200 reads information from the transfer memory 75 .

[0120] Specifically, the control unit 200 reads the tape ID (identification information) from the transfer memory 75 (S11). In addition, the control unit 200 reads the emission light amount LOA from the transfer memory 75 (S12). In addition, the control unit 200 reads the cumulative value VC from the transfer memory 75 (S13). In addition, the control unit 200 reads the degradation flag from the transfer memory 75 (S14). Thereafter, the control unit 200 performs the life determination process (S40). When the life determination process is completed, the control unit 200 ends the process and enters a state of waiting for an action request.

[0121] like Figure 6 As shown, the control unit 200 performs the light amount correction process (S24) when the number of printed sheets is the specified number of sheets (S21, Yes). In addition, the control unit 200 performs the light amount correction process (S24) when the installation environment of the image forming apparatus 1 is changed (S22, Yes). In addition, the control unit 200 performs the light amount correction process (S24) when there is an instruction to perform the light amount correction process due to the user's operation (S23, Yes).

[0122] After executing the light amount correction process, the control unit 200 uses the emission light amount LOB calculated by the light amount correction process as the emission light amount LO of the light emitted by the light emitting element 120 (S25). Thereafter, the control unit 200 executes the density correction process (S25), and when the density correction process is completed, the process is terminated.

[0123] If the number of printed sheets is not the specified number (S21, No), the installation environment of the image forming device 1 has not changed (S22, No), and there is no instruction to execute the light amount correction processing (S23, No), the control unit 200 does not execute the light amount correction processing and ends the processing.

[0124] like Figure 7 As shown, when the light amount correction process is executed (S31, Yes), the control unit 200 calculates a new cumulative value VC (S32) by adding the cumulative value VC (previous value) read from the transfer memory 75 to the value obtained by subtracting the output light amount LOA read from the transfer memory 75 from the output light amount LOB corrected by the most recent light amount correction process. Then, the control unit 200 writes the new cumulative value VC into the transfer memory 75 (S33) (first update process).

[0125] In addition, the control unit 200 replaces the emission light amount LOA with the emission light amount LOB corrected by the most recent light amount correction process (S34), and writes the new emission light amount LOA into the transfer memory 75 (S35) (second update process). When there is an update of the emission light amount LOA (S36, yes) or an update of the cumulative value VC (S37, yes), the control unit 200 performs a life determination process (S40).

[0126] like Figure 8 As shown, in the life determination process, the control unit 200 determines whether the belt ID is updated (S41). If the belt ID is updated (if the transfer belt 73 is replaced) (S41, Yes), the control unit 200 determines whether the degradation flag is on (S42). If it is determined that the degradation flag is not on (if it is off) (S42, No), the control unit 200 performs the light amount correction process (S43).

[0127] After executing the light amount correction process, the control unit 200 sets the emission light amount LOB calculated by the light amount correction process as the emission light amount LO of the light emitted by the light emitting element 120 ( S44 ), and executes the density correction process ( S45 ).

[0128] After executing the concentration correction process, the control unit 200 replaces the emission light amount LOA with the emission light amount LOB corrected by the most recent light amount correction process (S46), writes the new emission light amount LOA into the transfer memory 75 (S47), and executes the process of step S48. In addition, in step S41, if there is no update of the belt ID (if the transfer belt 73 is not replaced) (No), the control unit 200 executes the process of step S48.

[0129] In step S48, the control unit 200 determines whether the emission light amount LOA is greater than or equal to the second threshold value LOth (second determination process). When the emission light amount LOA is greater than or equal to the second threshold value LOth (S48, Yes), the control unit 200 performs the process of step S50. On the other hand, when the emission light amount LOA is not greater than or equal to the second threshold value LOth (S48, No), the control unit 200 determines whether the cumulative value VC is greater than or equal to the first threshold value VCth (S49) (first determination process).

[0130] When the cumulative value VC is not equal to or greater than the first threshold value VCth (S49, No), the control unit 200 terminates the process. When the cumulative value VC is equal to or greater than the first threshold value VCth (S49, Yes), the control unit 200 executes the process of step S50.

[0131] In step S50, the control unit 200 turns the degradation flag from off to on. Thereafter, the control unit 200 writes the degradation flag (on) into the transfer memory 75 (S51) (flag storage process). In addition, the control unit 200 causes the notification device 220 to display "Replace belt" (S52) (notification process), and the process ends. In addition, in step S42, when the degradation flag stored in the transfer memory 75 is on (yes), the control unit 200 also causes the notification device 220 to display "Replace belt" (S52) (notification process), and the process ends.

[0132] Next, the effects of the image forming apparatus 1 will be described.

[0133] By storing the cumulative value VC for determining that the transfer belt 73 is deteriorated in the transfer memory 75 , even if the transfer belt 73 is replaced, it is possible to determine whether the transfer belt 73 is deteriorated.

[0134] By executing the second determination process for determining that the transfer belt 73 has deteriorated when the emission light amount LOA is equal to or greater than the second threshold value LOth, it is possible to determine the degradation of the transfer belt 73 even based on the emission light amount LOA. In addition, by storing the emission light amount LOA in the transfer memory 75, it is possible to determine the degradation of the transfer belt 73 even when the transfer belt 73 is replaced.

[0135] By reading the cumulative value VC from the transfer memory 75 and executing the first determination process when the transfer unit 70 is mounted in the apparatus body 10 , it is possible to determine the deterioration of the transfer belt 73 based on the cumulative value VC stored in the transfer memory 75 .

[0136] By reading the emission light amount LOA from the transfer memory 75 and executing the second determination process when the transfer unit 70 is mounted in the apparatus body 10 , it is possible to determine the deterioration of the transfer belt 73 based on the emission light amount LOA stored in the transfer memory 75 .

[0137] By executing the light amount correction process when the number of printed sheets is a predetermined number of sheets, it is possible to correct the emitted light amount LO to an appropriate amount corresponding to the number of printed sheets.

[0138] By executing the light amount correction process when the installation environment of the image forming apparatus 1 changes, it is possible to correct the emission light amount LO to an appropriate level corresponding to the installation environment of the image forming apparatus 1 .

[0139] By executing the light amount correction process when the transfer unit 70 is replaced, it is possible to correct to an appropriate emission light amount LO corresponding to the replaced transfer belt 73 .

[0140] By storing the degradation flag in the transfer memory 75, the transfer unit 70 can be judged to be reusable when the degradation flag is not stored in the transfer memory 75 (when it is off), and cannot be reused when the degradation flag is stored in the transfer memory 75.

[0141] By executing the notification process of causing the notification device 220 to notify a message urging replacement of the transfer unit 70 , it is possible to notify the replacement timing of the transfer belt 73 .

[0142] When the transfer belt 73 is replaced, the light amount correction process is performed to calculate the emission light amount LOB, and the calculated emission light amount LOB is replaced with the emission light amount LOA, thereby calculating the cumulative value VC based on the initial emission light amount of the transfer belt 73. Since the surface state of the transfer belt 73 when it is new varies from one product to another, by calculating the cumulative value VC based on the initial emission light amount of the transfer belt 73, the deterioration of the transfer belt 73 can be appropriately determined.

[0143] When the cumulative value is stored in the memory of the device body, if a transfer belt in use or a recycled transfer belt is installed, the cumulative value of the change from the initial state cannot be calculated, and thus the deterioration of the transfer belt cannot be correctly determined. By storing the cumulative value VC in the transfer memory 75, the cumulative value VC of the change from the initial state can be calculated even if the transfer belt 73 in use or a recycled transfer belt 73 is installed, and thus the deterioration of the transfer belt 73 can be correctly determined.

[0144] Although the embodiment has been described above, the image forming apparatus can be implemented in various appropriately modified forms as exemplified below.

[0145] In the above-mentioned embodiment, the density correction process is executed after the light amount correction process is executed, but for example, both the density correction process and the color deviation correction process may be executed. The color deviation correction process is a process for correcting the position (color deviation) of the toner image of each color formed on the sheet S using the optical sensor 100 and the registration sensor RS.

[0146] In the above-mentioned embodiment, the light amount correction process is executed when an instruction indicating execution of the light amount correction process is received, but for example, the following configuration may be adopted: when an instruction indicating execution of the concentration correction process is received, the light amount correction process is executed before the concentration correction process is executed. In addition, the following configuration may be adopted: when an instruction indicating execution of the color deviation correction process is received, the light amount correction process is executed before the color deviation correction process is executed.

[0147] In the above-mentioned embodiment, the notification device 220 is a display, but the notification device may be, for example, a speaker that emits a sound or voice as a message urging the transfer unit to be replaced. In addition, for example, the notification device may be a lamp that lights up or flashes to notify the message urging the transfer unit to be replaced. In addition, the notification device may be a combination of two or more of a display, a speaker, a lamp, etc. In addition, the notification device may be a display of an external device connected to the image forming apparatus 1, etc.

[0148] In the above-mentioned embodiment, the control unit 200 is configured to make the notification device 220 notify the message urging the transfer unit 70 to be replaced when the transfer belt 73 is determined to be deteriorated. However, for example, the control unit 200 may be configured to update the correction coefficient Gsp in the density correction process when the transfer belt 73 is determined to be deteriorated. Specifically, the control unit 200 may be configured to make the correction coefficient Gsp larger than before the update when the transfer belt 73 is determined to be deteriorated. In this way, the density of the toner image formed on the sheet S can be maintained, and thus the image quality can be maintained.

[0149] In the above-described embodiment, the control unit 200 is configured to execute both the first determination process and the second determination process. However, for example, the control unit may be configured to execute the first determination process but not execute the second determination process.

[0150] In the above-described embodiment, the transfer belt 73 that conveys the sheet S between the photosensitive drum 51 is exemplified as the transfer belt, but the transfer belt may be, for example, an intermediate transfer belt.

[0151] In the above-mentioned embodiment, the image forming apparatus 1 is provided with the temperature and humidity sensor 210, but for example, the image forming apparatus may also be provided with a temperature sensor for detecting temperature and a humidity sensor for detecting humidity. The temperature sensor may detect the temperature inside the apparatus body or the temperature outside the apparatus body. The humidity sensor may detect the humidity inside the apparatus body or the humidity outside the apparatus body.

[0152] In addition, in order to determine the change of the installation environment of the image forming apparatus, the image forming apparatus may be configured to include only one of the temperature sensor and the humidity sensor. In addition, when the change of the installation environment of the image forming apparatus is not determined, the image forming apparatus may be configured to include neither the temperature sensor nor the humidity sensor.

[0153] In the above-described embodiment, the image forming apparatus 1 is a color printer, but the image forming apparatus may be, for example, a monochrome printer. Alternatively, the image forming apparatus may be a copy machine, a multifunction peripheral, or the like.

[0154] The respective elements described in the above-mentioned embodiment and modified examples may be implemented in any combination.

Claims

1. An image forming device comprising: Device body; a transfer unit which is detachable from the device body and includes a transfer memory and an endless transfer belt; a sensor including a light emitting element for emitting light and a light receiving element for receiving reflected light of the light emitted from the light emitting element; and Control Department, It is characterized in that The control unit performs the following processing: A light amount correction process for correcting the amount of emitted light, which is the amount of light emitted from the light emitting element, so that the amount of reflected light received by the light receiving element from a portion of the surface of the transfer belt where a toner image is not formed becomes a predetermined value; a concentration correction process for correcting the concentration of the toner image formed on the sheet based on reflected light from a portion of the surface of the transfer belt where a toner image for concentration correction is formed and reflected light from a portion of the surface of the transfer belt where no toner image is formed, which is received by the light receiving element after the light of the emitted light amount corrected by the light amount correction process is emitted from the light emitting element to the surface of the transfer belt; A first updating process of adding a change amount of the emitted light amount corrected by the light amount correction process relative to the emitted light amount corrected by the previous light amount correction process stored in the transfer memory to a cumulative value of the change amount stored in the transfer memory, thereby updating the cumulative value stored in the transfer memory; a second updating process of updating the emission light amount stored in the transfer memory to the emission light amount corrected by the most recent light amount correction process; as well as In the first determination process, when the cumulative value is equal to or greater than a first threshold value, it is determined that the transfer belt has deteriorated.

2. The image forming apparatus according to claim 1, wherein: The control unit executes a second determination process for determining that the transfer belt has deteriorated regardless of the cumulative value when the emission light amount is equal to or greater than a second threshold value.

3. The image forming apparatus according to claim 1, wherein: When it is determined that the transfer unit is attached to the apparatus body, the control unit reads the accumulated value from the transfer memory and executes the first determination process.

4. The image forming apparatus according to claim 2, wherein: When it is determined that the transfer unit is attached to the apparatus body, the control unit reads the emission light amount from the transfer memory and executes the second determination process.

5. The image forming apparatus according to any one of claims 1 to 4, characterized in that: The control unit executes the light amount correction process when it is determined that the number of printed sheets is a predetermined number of sheets.

6. The image forming apparatus according to any one of claims 1 to 4, characterized in that: The control unit executes the light amount correction process when it is determined that the installation environment of the image forming apparatus has changed.

7. The image forming apparatus according to claim 6, wherein: The control unit determines that the installation environment of the image forming apparatus has changed when the temperature has changed by a predetermined amount or more within a predetermined time.

8. The image forming apparatus according to claim 6, wherein: The control unit determines that the installation environment of the image forming apparatus has changed when the humidity has changed by a predetermined amount or more within a predetermined time.

9. The image forming apparatus according to any one of claims 1 to 4, characterized in that: The control unit executes the light amount correction process when it is determined that the transfer unit has been replaced.

10. The image forming apparatus according to any one of claims 1 to 4, characterized in that: The control unit stores a flag in the transfer memory when determining that the transfer belt has deteriorated.

11. The image forming apparatus according to claim 10, wherein: When the flag is stored in the transfer memory, the control unit executes a notification process to cause a notification device, which is a device for notifying a user of information, to notify a message urging replacement of the transfer unit.

12. The image forming apparatus according to any one of claims 1 to 4, characterized in that: When it is determined that the transfer belt has deteriorated, the control unit executes a notification process to cause a notification device, which is a device for notifying a user of information, to notify a message urging replacement of the transfer unit.

13. The image forming apparatus according to claim 2 or 4, characterized in that: The second threshold value is a maximum value of the amount of light that can be emitted from the light emitting element.

Images