Image forming device

Abstract

To provide an image forming apparatus that can accurately detect whether an installation location of the image forming apparatus is inappropriate.SOLUTION: An image forming apparatus 1 comprises a body housing 2, a fixing device 9, a first sensor 11, a second sensor 12, and a control unit 13. The first sensor 11 is located near a side wall 21A of the main body housing 2. The first sensor 11 can measure a first temperature and relative humidity. The second sensor 12 is located near a side wall 21B of the body housing 2. The second sensor 12 can measure a second temperature. When a temperature inside the apparatus TH calculated based on the second temperature exceeds a threshold T, the control unit 13 decreases the temperature inside the body housing 2. When a target temperature of the fixing device 9 is a print setting value, the first temperature has increased by a first predetermined value T1 or more compared with a first time earlier, and absolute humidity calculated from the relative humidity has increased by a second predetermined value H or more (S21: YES), the control unit 13 corrects the temperature inside the apparatus TH (S6, S7).SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to an image forming apparatus. [Background technology]

[0002] Conventionally, an image forming apparatus includes an internal temperature sensor and an external temperature sensor, and if the difference between the detection result of the internal temperature sensor and the detection result of the external temperature sensor is equal to or greater than a predetermined temperature, the image forming apparatus notifies the user that the installation location of the image forming apparatus is inappropriate (see Patent Document 1 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-58756 Summary of the Invention [Problem to be solved by the invention]

[0004] In the image forming device described in Patent Document 1, even if the installation location of the image forming device is appropriate, if the temperature around the image forming device changes due to the influence of air conditioning equipment or the like, the installation location of the image forming device may be mistakenly determined to be inappropriate.

[0005] Therefore, an object of the present disclosure is to provide an image forming apparatus that can accurately detect whether the installation location of the image forming apparatus is inappropriate. [Means for solving the problem]

[0006] (1) The image forming apparatus of the present disclosure includes a main body housing, a photosensitive drum, a developing roller, a fixing device, a first sensor, a second sensor, and a control unit. The main body housing has a first side wall and a second side wall. The first side wall has an exhaust port. The second side wall is located on the opposite side of the first side wall in a first direction. The developing roller supplies toner to the photosensitive drum. The fixing device heats the toner transferred from the photosensitive drum to a sheet and fixes it to the sheet.

[0007] The first sensor is located near a first side wall of the main body housing. The first sensor is located away from the exhaust port. The first sensor is capable of measuring a first temperature and relative humidity. The second sensor is located near a second side wall of the main body housing. The second sensor is located away from the fixing device. The second sensor is capable of measuring a second temperature.

[0008] The control unit executes a cooling-down process and a correction process.

[0009] The control unit executes a cooling-down process when the temperature near the developing roller calculated based on the second temperature exceeds a first threshold value. In the cooling-down process, the control unit lowers the temperature inside the main body housing.

[0010] The control unit executes a correction process when the target temperature of the fixing device is a print setting value, the first temperature has increased by a first predetermined value or more, and the absolute humidity calculated from the relative humidity has increased by a second predetermined value or more, compared to a first time before. In the correction process, the control unit corrects the temperature near the developing roller.

[0011] According to this configuration, the temperature in the vicinity of the developing roller is corrected based on not only the increase in the first temperature within the first time period but also the increase in the absolute humidity within the first time period.

[0012] Here, when a printing process is being performed, the moisture contained in the sheet evaporates when the sheet is heated by the fixing device.

[0013] Therefore, if the image forming apparatus is installed in an inappropriate location, the moisture inside the main body housing may not be properly discharged to the outside of the main body housing, and the absolute humidity inside the main body housing may increase excessively.

[0014] On the other hand, if the installation location of the image forming apparatus is appropriate, the moisture inside the main body housing is properly discharged to the outside of the main body housing, and therefore an increase in the absolute humidity inside the main body housing is suppressed.

[0015] Therefore, if the installation location of the image forming apparatus is appropriate and the temperature around the image forming apparatus increases due to the influence of air conditioning equipment or the like, the increase in absolute humidity inside the main body housing will be less than the second predetermined value.

[0016] As a result, it is possible to accurately detect whether the installation location of the image forming apparatus is appropriate.

[0017] (2) In the cooling-down process, the control unit changes the target temperature of the fixing device to a temperature lower than the print setting value until the temperature in the vicinity of the developing roller becomes lower than a second threshold value that is lower than the first threshold value.

[0018] According to this configuration, the control unit can lower the temperature near the developing roller by suspending the printing process and changing the target temperature of the fixing device to a temperature lower than the print setting value.

[0019] (3) In the correction process, the control unit may increase the temperature in the vicinity of the developing roller to a value higher than the value calculated based on the second temperature.

[0020] According to this configuration, if the first temperature increases by a first predetermined value or more and the absolute humidity increases by a second predetermined value or more compared to the first hour before, i.e., if the first temperature and absolute humidity increase excessively due to the printing process, the temperature near the developing roller is corrected to be higher.

[0021] This makes it easier for the corrected "temperature in the vicinity of the developing roller" to exceed the threshold value, and the cooling-down process can be executed earlier than before the correction.

[0022] As a result, the frequency with which the cooling-down process is executed can be increased.

[0023] (4) In the correction process, the control unit may add a correction value that changes at regular intervals to the temperature in the vicinity of the developing roller calculated based on the second temperature.

[0024] According to this configuration, by adding the correction value that changes at regular intervals, the temperature in the vicinity of the developing roller can be increased in accordance with increases in the first temperature and absolute humidity.

[0025] As a result, it is possible to prevent the calculation result of the temperature in the vicinity of the developing roller from suddenly changing.

[0026] (5) The image forming apparatus may further include a display unit. When the first temperature has increased by a first predetermined value or more and the absolute humidity has increased by a second predetermined value or more compared to a first hour before, the control unit may cause the display unit to display a message indicating that the installation location of the image forming apparatus is inappropriate.

[0027] With this configuration, the user can be prompted to change the installation location.

[0028] (6) When the first temperature increases by a first predetermined value or more and the absolute humidity increases by a second predetermined value or more compared to the first hour before, the control unit may cause the display unit to display a message indicating that the time until the cooling-down process is performed will be shortened.

[0029] With this configuration, the user can be notified that the frequency of the cooling-down process will increase. [Effects of the Invention]

[0030] According to the image forming apparatus of the present disclosure, it is possible to accurately detect whether the installation location of the image forming apparatus is inappropriate. [Brief explanation of the drawings]

[0031] [Figure 1]FIG. 1 is a schematic diagram of an image forming apparatus. [Figure 2] FIG. 2 is an explanatory diagram for explaining the arrangement of the fixing device, the first sensor, the second sensor, the fan, and the control unit in the image forming apparatus shown in FIG. [Figure 3] FIG. 3 is a block diagram for explaining control of the image forming apparatus shown in FIG. [Figure 4] FIG. 4 is a flowchart for explaining the control of the image forming apparatus. [Figure 5] FIG. 5 is a flowchart for explaining the improper installation state detection process in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0032] 1. Overview of image forming apparatus 1 An outline of an image forming apparatus 1 will be described with reference to FIG.

[0033] The image forming apparatus 1 includes a main body housing 2, a sheet storage section 3, a photosensitive drum 4, a charging device 5, an exposure device 6, a developing cartridge 7, a transfer device 8, and a fixing device 9.

[0034] 1.1 Main body casing 2 The main body housing 2 accommodates a sheet storage section 3, a photosensitive drum 4, a charging device 5, an exposure device 6, a developing cartridge 7, a transfer device 8, and a fixing device 9.

[0035] 1.2 Sheet storage section 3 The sheet storage unit 3 can store sheets S. The sheets S are, for example, printing paper. The sheets S are transported toward the photosensitive drum 4.

[0036] 1.3 Photosensitive drum 4 The photosensitive drum 4 has a cylindrical shape. The photosensitive drum 4 extends in a first direction. The photosensitive drum 4 is rotatable about an axis A1. The axis A1 extends in the first direction.

[0037] 1.4 Charging device 5 The charging device 5 charges the surface of the photosensitive drum 4. The charging device 5 is a scorotron charger. The charging device 5 may also be a charging roller.

[0038] 1.5 Exposure equipment 6 The exposure device 6 exposes the surface of the photosensitive drum 4 that has been charged by the charging device 5. The exposure device 6 is a laser scanning unit. The exposure device 6 may also be an LED array.

[0039] 1.6 Developer Cartridge 7 The developing cartridge 7 can be installed inside the main body housing 2. The developing cartridge 7 supplies toner onto the photosensitive drum 4. More specifically, the developing cartridge 7 supplies toner onto the surface of the photosensitive drum 4 exposed by the exposure device 6. The developing cartridge 7 has a developing housing 71, a developing roller 72, and a layer thickness regulating blade 73. In other words, the image forming apparatus 1 has the developing roller 72.

[0040] The developing casing 71 is capable of containing toner.

[0041] The developing roller 72 is capable of supplying toner in the developing housing 71 to the surface of the photosensitive drum 4. The developing roller 72 contacts the photosensitive drum 4. The developing roller 72 may be spaced apart from the photosensitive drum 4 by a predetermined distance. The developing roller 72 has a cylindrical shape. The developing roller 72 extends in a first direction. The developing roller 72 is rotatable about an axis A2. The axis A2 extends in the first direction.

[0042] The layer thickness regulating blade 73 regulates the layer thickness of the toner on the developing roller 72. If the temperature of the layer thickness regulating blade 73 rises excessively, the toner on the developing roller 72 may melt due to the heat of the layer thickness regulating blade 73 and adhere to the layer thickness regulating blade 73. If the toner adheres excessively to the layer thickness regulating blade 73, unevenness may occur in the printed image. Therefore, it is necessary to control the temperature of the layer thickness regulating blade 73.

[0043] 1.7 Transfer device 8 The transfer device 8 transfers the toner on the photosensitive drum 4 onto the sheet S. In this embodiment, the transfer device 8 has a transfer roller 81.

[0044] The transfer roller 81 contacts the photosensitive drum 4. The transfer roller 81 may be spaced a predetermined distance from the photosensitive drum 4. The sheet S in the sheet storage section 3 passes between the photosensitive drum 4 and the transfer roller 81 and is transported to the fixing device 9. The transfer roller 81 transfers the toner on the photosensitive drum 4 to the sheet S passing between the photosensitive drum 4 and the transfer roller 81. The transfer roller 81 has a cylindrical shape. The transfer roller 81 extends in a first direction. The transfer roller 81 is rotatable about an axis A3. The axis A3 extends in the first direction. The transfer device 8 may have a transfer belt.

[0045] 1.8 Fusing unit 9 The fixing device 9 applies heat and pressure to the sheet S onto which the toner has been transferred. The fixing device 9 heats the toner transferred from the photosensitive drum 4 to the sheet S, thereby fixing the toner to the sheet S. The sheet S that has passed through the fixing device 9 is discharged onto the top surface of the main body housing 2.

[0046] 2. Details of Image Forming Apparatus 1 Next, the image forming apparatus 1 will be described in detail with reference to FIGS.

[0047] As shown in FIG. 2, the image forming apparatus 1 includes a first sensor 11, a second sensor 12, a control unit 13, a display unit 14 (see FIG. 1), and a fan 15.

[0048] 2.1 Details of the main body 2 The main body housing 2 has two side walls 21A and 21B and two inner walls 22A and 22B.

[0049] The side wall 21A is one of the outer walls of the main body housing 2 in the first direction. The side wall 21A is located at one end of the main body housing 2 in the first direction. The side wall 21A extends in the vertical direction and the second direction. The second direction intersects with both the first direction and the vertical direction. The second direction is preferably perpendicular to the first direction and the vertical direction. The side wall 21A has an exhaust port 23.

[0050] The side wall 21B is the other outer wall of the main body housing 2 in the first direction. The side wall 21B is located at the other end of the main body housing 2 in the first direction. The side wall 21B is located on the opposite side to the side wall 21A in the first direction. The side wall 21B is located away from the side wall 21A in the first direction. The side wall 21A extends in the up-down direction and the second direction.

[0051] The inner wall 22A is located between the side wall 21A and the side wall 21B in the first direction. The inner wall 22A is located away from the side wall 21A in the first direction. The inner wall 22A extends in the vertical direction and the second direction.

[0052] The inner wall 22B is located between the inner wall 22A and the side wall 21B in the first direction. The inner wall 22B is located away from the inner wall 22A in the first direction. The inner wall 22B extends in the vertical direction and the second direction. The photosensitive drum 4, the developing cartridge 7, and the fixing device 9 are located between the inner wall 22A and the inner wall 22B in the first direction.

[0053] 2.2 First Sensor 11 The first sensor 11 is located near the side wall 21A of the main body housing 2 in the first direction. The first sensor 11 is located between the side wall 21A and the inner wall 22A in the first direction. The first sensor 11 is located away from the fixing device 9 in the second direction. The first sensor 11 is located on the opposite side of the fixing device 9 with respect to the photosensitive drum 4 in the second direction. The first sensor 11 is located away from the exhaust port 23 in the second direction. The first sensor 11 is located on the opposite side of the exhaust port 23 with respect to the photosensitive drum 4 in the second direction. The first sensor 11 is capable of measuring a first temperature and a relative humidity.

[0054] 2.3 Second Sensor 12 The second sensor 12 is located near the side wall 21B of the main body housing 2 in the first direction. The second sensor 12 is located between the side wall 21B and the inner wall 22B in the first direction. The second sensor 12 is located away from the fixing device 9 in the second direction. The second sensor 12 is located to the side of the developing roller 72 in the second direction. The second sensor 12 is capable of measuring a second temperature. The second temperature is different from the temperature of the layer thickness regulating blade 73 that is close to or in contact with the developing roller 72.

[0055] 2.4 Control Unit 13 As shown in FIG. 3, the control unit 13 is electrically connected to the first sensor 11, the second sensor 12, the display unit 14, and the fan 15. The control unit 13 is a circuit board having a processor and a memory. As shown in FIG. 2, the control unit 13 is located between the side wall 21A and the inner wall 22A in the first direction. An example of the processor is a CPU. The memory may be a volatile memory or a non-volatile memory. An example of the memory is a RAM or a ROM.

[0056] 2.5 Display section 14 1, the display unit 14 is located on the top surface of the main body housing 2. The display unit 14 is, for example, a display of an operation panel of the image forming apparatus 1.

[0057] 2.6 Fan 15 2, the fan 15 generates an airflow inside the main body housing 2 toward the exhaust port 23. The fan 15 is located near the side wall 21A of the main body housing 2 in the first direction. The fan 15 is located between the side wall 21A and the fixing device 9 in the first direction.

[0058] 3. Control of image forming apparatus 1 Next, control of the image forming apparatus 1 will be described with reference to FIGS.

[0059] If the installation location of the image forming apparatus 1 is inappropriate, the control unit 13 increases the frequency of the cooling down process.

[0060] Specifically, an inappropriate installation location for image forming apparatus 1 is when exhaust port 23 faces a wall. In the cooling-down process, control unit 13 stops the supply of power to fixing device 9, lowers the target temperature of fixing device 9 below the print setting value, and stops the supply of the next sheet S, thereby lowering the temperature inside main body housing 2.

[0061] When image forming apparatus 1 is put into an operating state, control unit 13 first resets (S1) the time Tn that has elapsed since the target temperature of fixing device 9 became the print setting value, the time Tm that has elapsed since the target temperature of fixing device 9 was no longer the print setting value, and a flag for when the installation location of image forming apparatus 1 is inappropriate. Note that if the installation location of image forming apparatus 1 is inappropriate, the flag is 1. If the installation location of image forming apparatus 1 is appropriate, the flag is 0. Resetting a flag means that the flag is set to 0.

[0062] Next, the control unit 13 executes an inappropriate installation state detection process (S2). The "inappropriate installation state detection process" is a process for detecting that the installation location of the image forming apparatus 1 is inappropriate.

[0063] 3.1 Improper installation detection process As shown in FIG. 5, in the inappropriate installation state detection process (S2), the control unit 13 first calculates the amount of increase ΔT of the current first temperature relative to the first temperature one hour ago. (out) The controller 13 determines whether the installation location is inappropriate based on the absolute humidity measured by the first sensor 11 and the increase ΔH in the current absolute humidity relative to the absolute humidity measured one hour ago.

[0064] Increase ΔT (out) If the increase ΔH is less than the first predetermined value T1 or the increase ΔH is less than the second predetermined value H (S21: NO), the installation location of the image forming apparatus 1 is appropriate.

[0065] On the other hand, the increase ΔT (out) If the increase ΔH is equal to or greater than the first predetermined value T1 and the increase ΔH is equal to or greater than the second predetermined value H (S21: YES), the installation location of the image forming apparatus 1 is inappropriate.

[0066] The first time is, for example, 1500 seconds. The first predetermined value T1 is, for example, 4° C. The second predetermined value H is, for example, 2 g / cm 3 is.

[0067] 3.1.1 Processing when the installation location of the image forming device 1 is appropriate (S21: NO) If the installation location of the image forming apparatus 1 is appropriate, the control unit 13 checks whether the flag is 0 (S22).

[0068] If the flag is 1 (S22: NO), the control unit 13 sets the flag to 0 (S23).

[0069] The control unit 13 also calculates the elapsed time T G Set to 0 and the elapsed time T G The control unit 13 starts measuring the temperature TH at the time of executing the process (S23) as the correction value ΔR0 immediately before the flag is switched (S23). The control unit 13 also stores the correction value ΔR at the time of executing the process (S23) as the correction value ΔR0 immediately before the flag is switched (S23). The control unit 13 also stores the internal temperature TH at the time of executing the process (S23) as the internal temperature TH0 immediately before the mode of the image forming apparatus 1 is switched (S23). The modes of the image forming apparatus 1 will be described later. The correction value ΔR is calculated in the process (S26), process (S27), process (S32), or process (S33) described later. The internal temperature TH is calculated in the process (S6), process (S7), process (S12), or process (S13) described later.

[0070] On the other hand, if the flag is 0 (S22: NO), the control unit 13 does not execute the process (S23).

[0071] Next, control unit 13 hides the message indicating that the installation location of image forming apparatus 1 is inappropriate (S24). More specifically, if a message indicating that the installation location of image forming apparatus 1 is inappropriate is displayed on display unit 14 (S22: NO), control unit 13 erases the message. On the other hand, if a message indicating that the installation location of image forming apparatus 1 is inappropriate is not displayed on display unit 14 (S22: YES), control unit 13 maintains the state.

[0072] Next, the control unit 13 calculates a correction value ΔR, which is used to calculate an internal temperature TH, which will be described later.

[0073] Elapsed time T G is equal to or shorter than the predetermined time T2 (S25: NO), the control unit 13 executes a first correction value calculation process (S26).

[0074] The predetermined time T2 is, for example, 20 seconds.

[0075] In the first correction value calculation process, the correction value ΔR is calculated by the following calculation formula (1).

[0076] Calculation formula (1): Correction value ΔR = Correction value ΔR0 × (1 - elapsed time T G / predetermined time T2) That is, the correction value ΔR changes at regular intervals.

[0077] On the other hand, the elapsed time T G If the time exceeds the predetermined time T2 (S25: YES), the correction value ΔR is set to 0 (S27).

[0078] 3.1.2 Processing when the installation location of the image forming device 1 is inappropriate (S21: YES) If the installation location of the image forming apparatus 1 is appropriate, the control unit 13 checks whether the flag is 1 (S28).

[0079] If the flag is 0 (S28: NO), the control unit 13 sets the flag to 1 (S29).

[0080] The control unit 13 also calculates the elapsed time T NG Set to 0 and the elapsed time T NG The control unit 13 starts measuring the temperature ΔR at the time of executing the process (S29) as a correction value ΔR0 (S29). The control unit 13 also stores the internal temperature TH at the time of executing the process (S23) as an internal temperature TH0 (S29). On the other hand, if the flag is 1 (S28: NO), the control unit 13 does not execute the process (S29).

[0081] Next, control unit 13 displays a message indicating that the installation location of image forming apparatus 1 is inappropriate (S30). That is, when the first temperature has increased by a first predetermined value T1 or more and the absolute humidity has increased by a second predetermined value H or more compared to the first hour before (S21: YES), control unit 13 causes display unit 14 to display a message indicating that the installation location of image forming apparatus 1 is inappropriate. Note that control unit 13 may also cause display unit 14 to display a message indicating that the time until the cooling-down process is performed will be shortened.

[0082] More specifically, if the display unit 14 does not display a message indicating that the installation location of the image forming apparatus 1 is inappropriate (S28: NO), the control unit 13 causes the display unit 14 to display a message indicating that the installation location of the image forming apparatus 1 is inappropriate. On the other hand, if the display unit 14 displays a message indicating that the installation location of the image forming apparatus 1 is inappropriate (S28: YES), the control unit 13 maintains that state.

[0083] Next, the control unit 13 calculates the correction value ΔR.

[0084] Elapsed time T NG is equal to or shorter than the predetermined time T2 (S31: NO), the control unit 13 executes a second correction value calculation process (S32).

[0085] In the second correction value calculation process, the correction value ΔR is calculated by the following calculation formula (2).

[0086] Calculation formula (2): Correction value ΔR = 2 × (elapsed time T NG / predetermined time T2) + correction value ΔR0 × (1 - elapsed time T NG / predetermined time T2) On the other hand, the elapsed time T NG If the time exceeds the predetermined time T2 (S31: YES), the correction value ΔR is set to 2 (S33).

[0087] When the calculation and setting of the correction value ΔR is completed, the control unit 13 ends the improper installation state detection process (S2).

[0088] 3.2 Calculation of internal temperature TH Next, the control unit 13 corrects the in-machine temperature TH based on the correction value ΔR calculated in the improper installation state detection process (S2). The in-machine temperature TH is an estimated temperature of the layer thickness regulating blade 73 near the developing roller 72. The in-machine temperature TH is calculated based on the second temperature measured by the second sensor 12.

[0089] If the target temperature of the fixing device 9 is the print setting value, i.e., if printing is in progress (S3: YES), the control unit 13 sets the elapsed time Tm since the target temperature of the fixing device 9 changed from the print setting value to 0 (S4), and if the elapsed time Tn since the target temperature of the fixing device 9 became the print setting value exceeds a predetermined time Tn1 (S5: NO), it executes a first internal temperature calculation process (S6).

[0090] The predetermined time Tn1 is, for example, 20 seconds.

[0091] In the first internal temperature calculation process (S6), the control unit 13 corrects the internal temperature TH using the following calculation formula (A). That is, if the target temperature of the fixing device 9 is the print setting value (S3: YES), and the first temperature has increased by a first predetermined value T1 or more and the absolute humidity has increased by a second predetermined value H or more compared to the first hour ago (S21: YES), the control unit 13 corrects the internal temperature TH. The first internal temperature calculation process (S6) is an example of a correction process.

[0092] Calculation formula (A): In-machine temperature TH=a×log (second temperature) 2 + b × log (second temperature) + c + correction value ΔR In the above formula (A), "a × log (second temperature) 2 +b×log(second temperature)+c" is the internal temperature TH when no correction is made. The internal temperature TH when no correction is made is calculated based on the second temperature. That is, in the correction process, the control unit 13 adds a correction value ΔR, which changes every certain time, to the internal temperature TH when no correction is made. As a result, in the correction process, the control unit 13 makes the internal temperature TH higher than the value calculated based on the second temperature. Note that a, b, and c are coefficients obtained by multiple regression analysis from experimental results.

[0093] On the other hand, if the elapsed time Tn is equal to or less than the predetermined time Tn1 (S5: YES), the control unit 13 executes a second internal temperature calculation process (S7).

[0094] In the second internal temperature calculation process (S7), the control unit 13 corrects the internal temperature TH using the following calculation formula (B): In other words, the second internal temperature calculation process (S7) is also an example of a correction process.

[0095] Calculation formula (B): In-machine temperature TH={a×log(2nd temperature) 2 + b × log (second temperature) + c + correction value ΔR} × Tn ÷ Tn1 + TH0 × (Tn1 - Tn) ÷ Tn1 Furthermore, if the target temperature of the fixing device 9 is not the print setting value, i.e., if printing is not in progress (S3: NO), the control unit 13 sets the elapsed time Tn since the target temperature of the fixing device 9 became the print setting value to 0 (S8), and if the elapsed time Tm since the target temperature of the fixing device 9 was no longer the print setting value is less than or equal to a predetermined time Tm1 (S9: YES), it executes a third internal temperature calculation process (S10).

[0096] The predetermined time Tm1 is, for example, 400 seconds.

[0097] In the third internal temperature calculation process (S10), the control unit 13 calculates the internal temperature TH using the following calculation formula (C): Note that in the third internal temperature calculation process (S10) and the fourth internal temperature calculation process (S11), the internal temperature TH is not corrected by the correction value ΔR.

[0098] Calculation formula (C): Internal temperature TH = TH0 × (Tm1 - Tm) ÷ Tm1 + second temperature × Tm ÷ Tm1 On the other hand, if the elapsed time Tm exceeds the predetermined time Tm1 (S9: NO), the control unit 13 executes a fourth internal temperature calculation process (S11).

[0099] In the fourth internal temperature calculation process (S11), the control unit 13 calculates the internal temperature TH using the following calculation formula (D).

[0100] Calculation formula (D): Inside temperature TH = 2nd temperature 3.3 Cooling down process Next, if the calculated internal temperature TH exceeds the first threshold value TH1 (S12: YES), the control unit 13 executes the cooling-down process (S13) and executes the improper installation detection process (S2) again.

[0101] The first threshold TH1 is, for example, 42°C.

[0102] On the other hand, if the calculated internal temperature TH is lower than the second threshold TH2 (S12: NO, S14: NO), the control unit 13 cancels the cooling-down process (S15) and executes the improper installation detection process (S2) again. The second threshold TH2 is lower than the first threshold TH1.

[0103] The second threshold TH2 is, for example, 41°C.

[0104] Furthermore, if the calculated internal temperature TH is less than the first threshold TH1 and exceeds the second threshold TH2 (S12: NO, S14: YES), the control unit 13 maintains the cooling-down process and executes the improper installation detection process (S2) again.

[0105] That is, in the cooling-down process (S13), the control unit 13 changes the target temperature of the fixing device 9 to a temperature lower than the print setting value until the internal temperature TH becomes lower than the second threshold value TH2.

[0106] 4. Effects (1) According to the image forming apparatus 1, as shown in FIG. 5, the increase amount ΔT of the first temperature within the first time period (out) In addition, the internal temperature TH is corrected (S6, S7) using the increase amount ΔH of absolute humidity within the first time period as a condition (S21).

[0107] Here, when a printing process is being performed, when the sheet S is heated by the fixing device 9, the moisture contained in the sheet S evaporates.

[0108] Therefore, if the installation location of the image forming device 1 is inappropriate and the exhaust port 23 faces a wall, the moisture inside the main body housing 2 will not be discharged outside the main body housing 2 through the exhaust port 23, and the absolute humidity inside the main body housing 2 may increase excessively.

[0109] On the other hand, if the installation location of the image forming apparatus 1 is appropriate, the moisture inside the main body housing 2 is discharged to the outside of the main body housing 2 through the exhaust port 23, so that an increase in the absolute humidity inside the main body housing 2 is suppressed.

[0110] Therefore, if the installation location of the image forming apparatus 1 is appropriate and the temperature around the image forming apparatus 1 is increasing due to the influence of air conditioning equipment or the like, the increase in absolute humidity ΔH inside the main body housing 2 will be less than the second predetermined value H.

[0111] As a result, it is possible to accurately detect whether the installation location of the image forming apparatus 1 is appropriate.

[0112] (2) According to the image forming apparatus 1, the control unit 13 lowers the target temperature of the fixing device 9 in the cooling-down process (S13) until the internal temperature TH becomes less than the second threshold value TH2 (S14: NO).

[0113] The control unit 13 can lower the temperature in the vicinity of the developing roller 72 by suspending the printing process and lowering the target temperature of the fixing device 9.

[0114] (3) According to the image forming device 1, the control unit 13 sets the internal temperature TH higher than the value calculated based on the second temperature in the first internal temperature calculation process (S6) and the second internal temperature calculation process (S7), which are examples of correction processes.

[0115] As a result, if the first temperature has increased by more than a first predetermined value and the absolute humidity has increased by more than a second predetermined value compared to the first hour ago (S21: YES, see Figure 5), that is, if the first temperature and absolute humidity have increased excessively due to the printing process, the internal temperature TH is corrected to be higher.

[0116] Therefore, when the corrected internal temperature TH exceeds the first threshold value T1 (S12: YES), the cooling-down process (S13) can be executed.

[0117] As a result, the frequency with which the cooling-down process is executed can be increased.

[0118] (4) According to the image forming apparatus 1, in the first internal temperature calculation process (S6) and the second internal temperature calculation process (S7), the correction value ΔR, which changes at regular intervals, is added to the internal temperature TH.

[0119] By adding the correction value ΔR that changes at regular intervals, the inside temperature TH can be gradually increased in accordance with increases in the first temperature and absolute humidity.

[0120] As a result, it is possible to prevent the calculation result of the internal temperature TH from suddenly changing.

[0121] (5) According to the image forming device 1, as shown in FIG. 5, when the first temperature has increased by a first predetermined value or more and the absolute humidity has increased by a second predetermined value or more compared to the first hour before (S21: YES), the control unit 13 causes the display unit 14 (see FIG. 1) to display a message indicating that the installation location of the image forming device 1 is inappropriate.

[0122] This can prompt the user to change the installation location.

[0123] (6) According to the image forming device 1, as shown in FIG. 5, when the first temperature increases by a first predetermined value or more and the absolute humidity increases by a second predetermined value or more compared to the first hour before (S21: YES), the control unit 13 causes the display unit 14 to display a message indicating that the time until the cooling-down process is performed will be shortened.

[0124] This allows the user to be notified that the frequency of the cooling down process will increase. [Explanation of symbols]

[0125] 1. Image forming device 2 Main unit housing 4 Photosensitive drum 9 Fixing device 11 First sensor 12 Second sensor 13 Control Unit 14 Display section 21A Side wall (1st side wall) 21B Side wall (2nd side wall) 23 Exhaust port 72 Developing roller TH In-flight temperature TH1 First threshold TH2 Second threshold

Claims

1. a main body housing having a first side wall having an exhaust port and a second side wall located on the opposite side of the first side wall in a first direction; A photosensitive drum; a developing roller that supplies toner to the photosensitive drum; a fixing device that fixes the toner transferred from the photosensitive drum to the sheet by heating; a first sensor located near the first side wall of the main body housing and away from the exhaust port, the first sensor being capable of measuring a first temperature and a relative humidity; a second sensor located near the second side wall of the main body housing and away from the fixing device, the second sensor being capable of measuring a second temperature; a control unit, The control unit a cooling-down process for lowering the temperature inside the main body casing when the temperature near the developing roller calculated based on the second temperature exceeds a first threshold value; and performing a correction process to correct the temperature near the developing roller when the target temperature of the fixing device is a print setting value, the first temperature increases by more than a first predetermined value compared to a first time ago, and the absolute humidity calculated from the relative humidity increases by more than a second predetermined value.

2. 2. The image forming apparatus according to claim 1, wherein the control unit changes the target temperature of the fixing device to a value lower than the print setting value during the cooling-down process until the temperature near the developing roller becomes lower than a second threshold value that is lower than the first threshold value.

3. 3. The image forming apparatus according to claim 1, wherein the control unit, in the correction process, makes the temperature in the vicinity of the developing roller higher than a value calculated based on the second temperature.

4. 4. The image forming apparatus according to claim 3, wherein the control unit adds a correction value that changes at regular intervals to the temperature in the vicinity of the developing roller calculated based on the second temperature in the correction process.

5. The image forming apparatus further includes a display unit, The control unit 2. The image forming apparatus according to claim 1, wherein, when the first temperature increases by more than the first predetermined value and the absolute humidity increases by more than the second predetermined value compared to the first time period, the display unit displays a message indicating that the installation location of the image forming apparatus is inappropriate.

6. The image forming apparatus further includes a display unit, The control unit 2. The image forming apparatus according to claim 1, wherein, when the first temperature increases by more than the first predetermined value and the absolute humidity increases by more than the second predetermined value compared to the first time period, the display unit displays a message indicating that the time until the cooling-down process is performed will be shortened.

Images