JP6569308B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus including a developing unit and a fixing device having a heating unit for heating a sheet.

  2. Description of the Related Art Some conventional electrophotographic image forming apparatuses are configured such that after a developer image is formed on a sheet by a developing unit having a developing roller, the sheet is heated by a fixing unit having a heating unit. In such an image forming apparatus, when the temperature of the developing unit rises to near the melting point of the developer due to friction generated in the developing unit or heat from the heating unit, the developer may be deteriorated. In order to prevent the developing unit from becoming high in this manner, for example, in the image forming apparatus disclosed in Patent Document 1, an in-apparatus temperature measuring unit that measures the temperature of the developing unit is provided in the developing unit. Control is performed to suppress an increase in the temperature of the developing device from the temperature inside the developing unit measured by the temperature measuring means and the outside air temperature.

JP 2013-190753 A

  However, the above-described technique has a problem that the cost of the developing unit increases because the developing unit is provided with the temperature measuring means in the apparatus.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus that can appropriately control cooling of a developing unit and suppress deterioration of a developer while suppressing the cost of a developing device.

In order to achieve the above-described object, an image forming apparatus of the present invention includes a developing roller, a developing unit that forms a developer image on a sheet, a fixing unit that includes a heating unit that heats the sheet, a developing unit, A housing that houses the fixing device, an in-machine temperature sensor that detects an in-machine temperature that is a temperature inside the housing, an outside air temperature sensor that detects an outside air temperature that is a temperature outside the housing, and a control unit. .
The control unit calculates the temperature of the developing unit based on the in-machine temperature, the outside air temperature, and the driving state of the developing roller, and executes cooling control based on the obtained temperature of the developing unit.

  According to the image forming apparatus configured as described above, since it is not necessary to provide a temperature sensor in the developing unit, the cost of the developing unit can be suppressed. And by calculating the temperature of a developing part, cooling control can be performed appropriately and deterioration of a developer can be controlled.

  According to the present invention, since it is not necessary to provide a temperature sensor in the developing unit, the cost of the developing unit can be suppressed. And by calculating the temperature of a developing part, cooling control can be performed appropriately and deterioration of a developer can be controlled.

1 is a diagram illustrating a schematic configuration of a laser printer according to an embodiment of the present invention. It is a figure which shows the structure of a control part. It is a flowchart explaining operation | movement of a control part. It is a flowchart explaining the temperature calculation by a control part. It is a flowchart explaining the temperature calculation by a control part. It is a flowchart explaining the temperature calculation by a control part. It is a flowchart explaining the temperature calculation by a control part. It is a flowchart explaining the cold start determination by a control part. It is a flowchart explaining the temperature determination by a control part. It is a flowchart explaining the process at the time of the cover opening by a control part.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In the following description, first, the overall configuration of a laser printer as an example of an image forming apparatus according to the present invention will be described, and then the features of the present invention will be described in detail.

  In the following description, the direction is “front side” on the right side of the page of FIG. 1, “rear side” on the left side of the page, “right side” on the back side of the page, and front side of the page. Is “left side”. In addition, the vertical direction toward the page is defined as the “vertical direction”.

  As shown in FIG. 1, the laser printer 1 includes a housing 2, a sheet feeding unit 3 for feeding a sheet P as an example of a sheet to the image forming unit 4, and an image for forming an image on the sheet P. An image forming unit 4 and a transport unit 9 are provided.

  The housing 2 accommodates the paper feed unit 3 and the image forming unit 4 therein, and mainly includes a pair of left and right main body frames 21, an upper panel 22 that connects the upper portions of the main body frames 21, and each main body frame. A front cover 23 and a rear cover 24 are provided as an example of a cover provided so as to be rotatable with respect to 21. On the upper panel 22, a paper discharge tray 22 </ b> A for placing the paper P discharged outside the housing 2 is formed.

  The front cover 23 is a cover that opens and closes an opening 2A formed on the front side of the housing 2, and is provided so as to be rotatable about a rotation shaft 23B disposed at the lower end. The rear cover 24 is a cover that opens and closes the rear portion of the housing 2, and is provided so as to be rotatable about a rotation shaft 24 </ b> B disposed at the lower end. The laser printer 1 can discharge the paper P carried out from the image forming unit 4 from the rear part of the housing 2 to the rear side by opening the rear cover 24.

  The paper feed unit 3 includes a paper feed tray 31 that is provided in the lower part of the housing 2 and is detachably mounted from the front side, and a pressure plate 32 provided in the paper feed tray 31. The paper feed unit 3 is provided on the downstream side of the paper feed direction of the paper P with respect to the paper feed roller 33 provided above the front end of the paper P stacked in the paper feed tray 31. A separation roller 34 and a separation pad 35 are provided.

  Further, the paper feed unit 3 includes a paper dust removing roller 36 provided on the downstream side in the transport direction of the separation roller 34 and a registration roller 37 provided on the downstream side in the transport direction of the paper dust removing roller 36.

  In the paper feed unit 3 configured as described above, the paper P in the paper feed tray 31 is urged to the paper feed roller 33 by the pressure plate 32 and is sent out by the paper feed roller 33 to be separated from the separation roller 34 and the separation roller 34. Separated by a pad 35. Thereafter, after the paper dust is removed by the paper dust removing roller 36, the front end position is aligned by the registration roller 37 and the paper P is conveyed to the image forming unit 4 at an appropriate timing.

  The image forming unit 4 includes a scanner unit 5, a process cartridge 6 as an example of a developing unit, and a fixing device 7.

  The scanner unit 5 is provided in an upper part of the housing 2 and includes a laser light emitting unit (not shown), a polygon mirror, a lens, a reflecting mirror, and the like that are not shown. The scanner unit 5 scans a laser beam to expose the surface of a photosensitive drum 61 described later.

  The process cartridge 6 is configured to be detachable from the housing 2 through an opening 2 </ b> A formed by opening the front cover 23. The process cartridge 6 includes a photosensitive drum 61, a transfer roller 62 facing the photosensitive drum 61, and the developing cartridge 10.

  The developing cartridge 10 mainly includes a developing roller 123, a supply roller 122, a layer thickness regulating blade 124 in contact with the developing roller 123, and a toner storage unit 111 that stores toner as an example of a developer.

  The laser printer 1 includes a reading unit 30 that reads information from the IC 10 </ b> A mounted on the developing cartridge 10. The laser printer 1 can detect that the developing cartridge 10 has been replaced with a new one based on the reading result of the reading unit 30.

  In the process cartridge 6, the surface of the rotating photosensitive drum 61 is uniformly charged by a charger and then exposed by scanning with a laser beam from the scanner unit 5. As a result, an electrostatic latent image based on the image data is formed on the surface of the photosensitive drum 61. The toner in the toner storage unit 111 is first supplied to the supply roller 122 and then supplied from the supply roller 122 to the developing roller 123. The toner supplied to the developing roller 123 is carried on the developing roller 123 with the layer thickness regulated between the developing roller 123 and the layer thickness regulating blade 124 as the developing roller 123 rotates.

  The toner carried on the developing roller 123 is supplied from the developing roller 123 to the electrostatic latent image formed on the photosensitive drum 61. As a result, the electrostatic latent image is visualized, and a toner image as an example of a developer image is formed on the photosensitive drum 61. Thereafter, the sheet P is conveyed between the photosensitive drum 61 and the transfer roller 62, whereby the toner image on the photosensitive drum 61 is transferred onto the sheet P.

  The fixing device 7 includes a heating unit 71 that heats the paper P including a halogen heater, a fixing belt, a nip plate, and the like that are omitted from the reference numerals, and a pressure that clamps the fixing belt between the nip plate of the heating unit 71. And a roller 72. In the fixing device 7 configured as described above, the toner transferred onto the paper P is thermally fixed while the paper P passes between the heating unit 71 and the pressure roller 72.

  The transport unit 9 functions as a discharge mechanism that discharges the paper P carried out of the image forming unit 4 to the outside of the housing 2, and displays the front and back sides of the paper P on which one image is formed by the image forming unit 4. It functions as a re-conveying means for conveying the paper P again to the image forming unit 4 in the inverted state. Specifically, the transport unit 9 mainly includes a transport path 91, a discharge roller 92, and a re-transport path 93.

  The conveyance path 91 extends from the rear of the fixing device 7 upward and then extends so as to curve the course forward.

  The discharge roller 92 is configured to be rotatable in both forward and reverse directions, and discharges the paper P transported from the image forming unit 4 toward the outside of the housing 2 during forward rotation, and discharges the paper P into the housing during reverse rotation. 2 so as to be pulled in.

  The re-conveying path 93 is configured to convey the paper P on which an image is formed on one side by the image forming unit 4 to the image forming unit 4 again under the image forming unit 4.

  In the transport unit 9, when the image formation is completed, the paper P transported from the image forming unit 4 is transported through the transport path 91 and is discharged to the outside of the housing 2 by the discharge roller 92 that rotates forward. It is placed on the paper tray 22A. Further, when an image is formed on the other side of the paper P having an image formed on one side, the discharge roller 92 rotates in reverse before the entire paper P is completely discharged to the outside of the housing 2. As a result, the paper P is pulled back into the housing 2 again, and is transported from the transport path 91 to the re-transport path 93. Thereafter, as indicated by a broken line, the paper P is transported along the re-transport path 93 and is transported again to the image forming section 4 by the paper feed section 3.

  The housing 2 includes a fan 81, an in-machine temperature sensor SE1, an air inlet 82, and an outside air temperature sensor SE2.

  The fan 81 is disposed obliquely above and in front of the fixing device 7. The fan 81 is configured to suck the air in the housing 2 and discharge it outside, and is provided on the right main body frame 21 of the pair of left and right main body frames 21.

  The air inlet 82 is an opening for taking in air from the outside provided in the rear part of the housing 2, and is formed in one of the pair of left and right main body frames 21. Specifically, the air inlet 82 is disposed on the side opposite to the process cartridge 6 with the fixing device 7 interposed therebetween in the front-rear direction. The air inlet 82 is disposed below the fixing device 7 in the vertical direction. That is, the air inlet 82 is disposed at a position that is not easily affected by the heat generated by the fixing device 7 and the process cartridge 6.

  The in-machine temperature sensor SE1 is, for example, a thermistor, and is configured to detect an in-machine temperature that is the temperature in the housing 2. The in-machine temperature sensor SE1 is disposed at a position between the fixing device 7 and the developing roller 123 in the housing 2 in the front-rear direction. The in-machine temperature sensor SE1 is disposed on one of the pair of left and right body frames 21. That is, the in-machine temperature sensor SE <b> 1 is disposed outside the process cartridge 6 in the housing 2.

  The outside air temperature sensor SE2 is a thermistor, for example, and is disposed facing the inside of the air inlet 82. The outside air temperature sensor SE <b> 2 is configured to detect the outside air temperature that is the temperature outside the housing 2 by detecting the temperature of the air taken in from the air inlet 82.

  As shown in FIG. 2, the laser printer 1 further includes a front cover opening / closing sensor 23 </ b> A that detects opening / closing of the front cover 23, a rear cover opening / closing sensor 24 </ b> A that detects opening / closing of the rear cover 24, and a control unit 100. Yes.

  The front cover open / close sensor 23A and the rear cover open / close sensor 24A output an ON signal to the control unit 100 when the covers 23, 24 are closed, and output an ON signal to the control unit 100. The covers 23 and 24 are separated from each other and the OFF signal is output to the control unit 100.

  The control unit 100 includes a CPU, a RAM, a ROM, and the like, a program stored in the ROM, a print job input from a personal computer connected to the laser printer 1, an in-machine temperature sensor SE1, an outside air temperature sensor SE2, a front The image forming unit 4 is configured to be controlled based on signals input from the cover opening / closing sensor 23A and the rear cover opening / closing sensor 24A.

  Specifically, the control unit 100 calculates the temperature of the process cartridge 6 based on the in-machine temperature, the outside air temperature, and the driving state of the developing roller 123, and executes cooling control based on the obtained temperature of the process cartridge 6. Is configured to do.

  The control unit 100 mainly includes a print control unit 110, a fan control unit 120, a cover open / close determination unit 130, a temperature calculation unit 140, and a storage unit 150.

  The print control unit 110 is configured to be able to control the image forming unit 4. Specifically, the print control unit 110 controls the motor 4A for driving the developing roller 123 and the drive transmission mechanism 4B that connects the motor 4A and the developing roller 123 to rotate, stop, and rotate the developing roller 123. The speed is controlled. The drive transmission mechanism 4B is configured to be able to change the speed of the developing roller 123 relative to the speed of the motor 4A by changing the reduction ratio between the motor 4A and the developing roller 123.

  The print control unit 110 is configured to be able to control the fixing device 7. In the present embodiment, the print control unit 110 puts the fixing device 7 into a ready state or a sleep state when the print process is not being performed. The ready state is a state in which the fixing device 7 is maintained at a predetermined temperature, and the sleep state is a state in which the fixing device 7 is OFF.

  Then, the print control unit 110 controls the paper feed unit 3, the conveyance unit 9, and the like, so that one-sided printing that prints on one side of the paper P and one-sided printing that is printed on one side based on the input print job. 7 is configured to carry out double-sided printing in which the paper P heated by 7 is conveyed again to the process cartridge 6 and printed on both sides of the paper P.

  In addition, when performing single-sided printing, the print control unit 110 is configured to determine whether or not to print on a small size paper based on a print job. In this embodiment, the size of a normal paper P that is not a small size paper is A4 or letter size, and the small size paper is a paper P of A5 size or smaller.

  The fan control unit 120 is configured to control operation / stop of the fan 81 by controlling the fan 81. Further, the fan control unit 120 operates the fan 81 at full speed or at a speed slower than full speed. The fan 81 is operated at full speed, for example, when printing is continuously performed by the image forming unit 4, and when the fan 81 is operated at a speed slower than the full speed, for example, preparation before printing is performed. It is during operation or after the end of printing.

  The cover open / close determining unit 130 is configured to determine whether the front cover 23 is open or closed based on a signal from the front cover open / close sensor 23A. When the cover open / close determining unit 130 determines that the front cover 23 is open, the cover open / close determining unit 130 can count the time during which the front cover 23 is open. The cover open / close determining unit 130 is configured to determine whether the rear cover 24 is open or closed based on a signal from the rear cover open / close sensor 24A.

  The temperature calculation unit 140 calculates a differential temperature, which is a temperature change of the process cartridge 6 from the previous calculation to the present, at predetermined time intervals based on the in-machine temperature, the outside air temperature, the driving state of the developing roller 123, and the like. Then, the sum of the obtained differential temperature and the previously calculated temperature of the process cartridge 6 is calculated as the current temperature of the process cartridge 6. In the present embodiment, the temperature calculation unit 140 calculates the temperature of the layer thickness regulating blade 124 and the temperature of the developing roller 123 as the temperature of the process cartridge 6.

Specifically, the current temperature T _B (n) [° C.] of the layer thickness regulating blade 124 is the same as the previously calculated temperature T _B (n−1) [° C.] of the layer thickness regulating blade 124. Using the difference temperature ΔT _B [° C.] of 124,
T _B (n) = T _B (n−1) + ΔT _B (1)
It is calculated by the operation.

Further, the current temperature T _D (n) [° C.] of the developing roller 123 is equal to the previously calculated temperature T _D (n−1) [° C.] of the developing roller 123 and the difference temperature ΔT _D [° C.] of the developing roller 123. Using,
T _D (n) = T _D (n−1) + ΔT _D (2)
It is calculated by the operation.

Here, the difference temperature ΔT _B [° C.] of the layer thickness regulating blade 124 in the equation (1) is the amount of heat ΔE _in−B (n) [J] transferred from the air in the machine to the layer thickness regulating blade 124 and the layer thickness. Using the amount of heat ΔE _out-B (n) [J] that moves from the regulating blade 124 to the outside air and the calorific value Q _B [W] of the layer thickness regulating blade 124,
ΔT _B
= (ΔE _in−B (n) −ΔE _out−B (n) + Q _B × Δt) / C _B (3)
However,
C _B [J / ° C.] Heat capacity of layer thickness regulating blade Δt [s] It is obtained by the calculation of the time from the previous calculation to the present.

Note that the amount of heat ΔE _in-B (n) [J] transferred from the air in the machine to the layer thickness regulating blade 124 in the equation (3) is the previously obtained in-machine temperature T _in (n−1) [° C.]. Using the calculated temperature T _B (n−1) [° C.] of the layer thickness regulating blade 124 and the thermal resistance R _in-B [° C./W] between the air in the machine and the layer thickness regulating blade 124,
ΔE _in-B (n)
= (T _in (n−1) −T _B (n−1)) × Δt / R _in−B (4)
It is calculated by the operation.

In addition, the amount of heat ΔE _out-B (n) [J] transferred from the layer thickness regulating blade 124 to the outside air in the equation (3) was previously calculated as the previously acquired outside air temperature T _out (n−1) [° C.]. Using the temperature T _B (n−1) [° C.] of the layer thickness regulating blade 124 and the thermal resistance R _out-B [° C./W] between the outside air temperature and the layer thickness regulating blade 124,
ΔE _out-B (n)
= (T _B (n-1) -T _out (n-1)) × Δt / R _out-B (5)
It is calculated by the operation.

Note that Q _B , C _B , R _in-B , and R _{out-B in the} expressions (3) to (5) are constants used when calculating the temperature of the layer thickness regulating blade 124. It depends on the state of the laser printer 1 such as the driving state.

Next, the difference temperature ΔT _D [° C.] of the developing roller 123 will be described. Since the developing roller 123 is in contact with the photosensitive drum 61, there is an influence of heat received from the paper P in addition to frictional heat with the layer thickness regulating blade 124. Therefore, the temperature of the developing roller 123 is calculated in consideration of the heat at the contact point between the developing roller 123 and the photosensitive drum 61.

The differential temperature ΔT _D [° C.] of the developing roller in equation (2) is the amount of heat ΔE _in−D (n) [J] that moves from the air in the machine to the developing roller 123 and the amount of heat ΔE that moves from the developing roller 123 to the outside air. _out-D (n) [J] and the amount of heat ΔE _P-D (n) [J] moving from the contact point between the developing roller 123 and the photosensitive drum 61 to the developing roller 123,
ΔT _{D
= (Δ E in-D (} n) + Δ E P-D (n) -Δ E out-D (n)) / C D ·· (6)
However,
C _D [J / ° C.] Calculated by calculation of the heat capacity of the developing roller.

Note that (6) heat ΔE _in-D (n) from the air in the machine that put moves to the developing roller 123 in the formula [J] is the internal temperature _T in (n-1) acquired previously [° C.], Using the previously calculated temperature T _D (n−1) [° C.] of the developing roller 123 and the thermal resistance R _in-D [° C./W] between the air in the apparatus and the developing roller 123,
ΔE _in-D (n)
= (T _in (n−1) −T _D (n−1)) × Δt / R _in−D (7)
It is calculated by the operation.

Further, the amount of heat ΔE _out-D (n) [J] transferred from the developing roller 123 to the outside air in the expression (6) is the previously acquired outside air temperature T _out (n−1) [° C.] and the previously calculated developing roller. 123 using a temperature T _D (n−1) [° C.] and a thermal resistance R _out-D [° C./W] between the outside air temperature and the developing roller 123,
ΔE _out-D (n)
_{= (T D (n-1} ) -T out (n-1)) × Δt / R out-D ·· (8)
It is calculated by the operation.

The amount of heat ΔE _P−D (n) [J] transferred from the contact point between the developing roller 123 and the photosensitive drum 61 to the developing roller 123 in the equation (6) is the temperature of the contact point between the developing roller 123 and the photosensitive drum 61 previously calculated. T _P (n−1) [° C.], the previously calculated temperature T _D (n−1) [° C.] of the developing roller 123, and the thermal resistance between the developing roller 123 and the contact point of the photosensitive drum 61 and the developing roller 123. _RP-D [° C./W]
ΔE _P-D (n)
_{= (T P (n-1} ) -T D (n-1)) × Δt / R P-D ·· (9)
It is calculated by the operation. Note that the temperature T _P (n) [° C.] of the contact point between the developing roller 123 and the photosensitive drum 61 is obtained by using the heat generation amount Q _P [W] at the contact point between the developing roller 123 and the photosensitive drum 61.
T _P (n)
= (Q _P × Δt−Δ E _P−D (n)) / C _P + T _P (n−1) (10)
However,
C _P [J / ° C.] Calculated by calculation of the heat capacity of the contact point between the developing roller and the photosensitive drum.

C _D , R _in-D , R _out-D , R _P-D , Q _P , and C _{P in the} expressions (6) to (10) are constants used when calculating the temperature of the developing roller 123. It differs depending on each state such as the driving state of the developing roller 123.

The temperature calculation unit 140 indicates the driving state of the developing roller 123, the opening / closing state of the rear cover 24, the case of executing single-sided printing and the case of executing double-sided printing, the size of the paper P, the driving state of the fan 81, and the state of the fixing unit 7. In accordance with each state, the constants (Q _B , C _B , R _in-B , R _out-B , C _D , R _in-D , R _out-D , R _P-D , Q _P , C _P ) are obtained, and the temperature of the layer thickness regulating blade 124 and the temperature of the developing roller 123 are calculated using the obtained constants. At this time, the time Δt [s] from the previous calculation to the present time may be a different value between the normal time and the power saving mode, and any time interval can be obtained by obtaining Δt [s] during the calculation. It is possible to calculate with. That is, when the printing operation is not performed for a predetermined time, the calculation time interval can be set long as the power saving mode.

  Here, the driving state of the developing roller 123 is the driving / stopping of the motor 4A for driving the developing roller 123 and the rotational speed of the developing roller 123 in this embodiment. The temperature calculation unit 140 may determine the rotation speed of the developing roller 123 from the rotation speed of the developing roller 123 set by the print control unit 110, or from the operation state of the motor 4A and the driving state of the drive transmission mechanism 4B. May be.

The temperature calculating unit 140, the calculated temperature _T B of the layer thickness regulating blade 124 (n) [℃] temperature _T D of the developing roller 123 (n) [℃], the previous operation is used in the next operation as the temperature _T B of the layer thickness regulating blade 124 (n-1) [℃ ] temperature _T D (n-1) of the developing roller 123 [° C.], is configured to be stored in the storage unit 150. In addition, the temperature calculation unit 140 uses the in-machine temperature T _in (n) [° C.] and the outside air temperature T _out (n) [° C.] used in the current calculation for the previous in-machine temperature T _in (n -1) It is comprised so that it may memorize | store in the memory | storage part 150 as [ _degreeC ] and external temperature _Tout (n-1) [degreeC].

  Then, the temperature calculation unit 140 determines whether the obtained temperature of the layer thickness regulating blade 124 and the temperature of the developing roller 123 are appropriate values, and if not, improper cooling control is executed. In order to suppress this, the calculation result is reset.

Specifically, the temperature calculation unit 140 determines that the difference between the temperature of the obtained layer thickness regulating blade 124 and the in-machine temperature, and the difference between the obtained temperature of the developing roller 123 and the in-machine temperature are within a predetermined range. The temperature T _B (n) of the layer thickness regulating blade 124 and the temperature T _D (n) of the developing roller 123 are not in the range of the first predetermined temperature T1 [° C.] or more and the second predetermined temperature T2 [° C.] or less. Are set to the _in- machine temperature T _in (n) [° C.], respectively. Further, the temperature calculation unit 140 determines that when the difference between the temperature of the developing roller 123 and the temperature of the layer thickness regulating blade 124 is not within the second predetermined range, specifically, when it is greater than the third predetermined temperature T3 [° C.]. It is adapted to set the temperature _T B (n) and the temperature _T D (n) the temperature inside each _T in the developing roller 123 of the layer thickness regulating blade 124 (n) [℃].

In addition, when the laser printer 1 is turned on, the temperature calculation unit 140 determines that the difference between the internal temperature measured at that time and the outside air temperature is equal to or less than a sixth predetermined temperature T6 [° C.], or the internal temperature is When the temperature T _B (n) ′ [° C.] of the layer thickness regulating blade 124 stored in the storage unit 150 and the temperature T _D (n) ′ [° C.] of the developing roller 123 are lower, the current layer thickness regulating blade The temperature T _B (n) 124 and the current temperature T _D (n) of the developing roller 123 are set to the same value as the _in- machine temperature T _in (n) [° C.]. Thereby, even if the laser printer 1 is in the OFF state for a long time and the temperature of the developing cartridge 10 is lower than the previous calculation, an appropriate calculation result can be obtained.

When the power of the laser printer 1 is turned on, the temperature calculation unit 140 has a difference between the internal temperature measured at that time and the outside air temperature is larger than the sixth predetermined temperature T6 [° C.], and the internal temperature is When the temperature T _B (n) ′ [° C.] of the layer thickness regulating blade 124 stored in the storage unit 150 and the temperature T _D (n) ′ [° C.] of the developing roller 123 are equal to or higher than the current layer thickness regulating blade 124. The temperature T _B (n) and the current temperature T _D (n) of the developing roller 123, the temperature T _B (n) ′ [° C.] of the layer thickness regulating blade 124 stored in the storage unit 150, and the current developing roller A temperature T _D (n) ′ of 123 is set to “° C.”. As a result, even if the power of the laser printer 1 is turned off after printing and the power is turned on again before the temperature inside the apparatus is sufficiently lowered, an appropriate calculation result can be obtained.

Further, when the temperature calculation unit 140 detects that the developing cartridge 10 has been replaced, the temperature T _B (n) of the current layer thickness regulating blade 124 and the temperature T _D (n) of the developing roller 123 are converted into the in-machine temperature T. _in (n) [° C.]. As a result, even if the developing cartridge 10 is replaced and the developing cartridge 10 having a lower temperature than that calculated at the previous time is mounted, an appropriate calculation result can be obtained.

When the front cover 23 is opened after being opened for a predetermined time or more, for example, 3 minutes or more and then closed, the temperature calculation unit 140 calculates the temperature of the layer thickness regulating blade 124 and the temperature of the developing roller 123 as the in-machine temperature T. If _in (n) [° C.] is higher than the set temperature _T D of the temperature _T B of the current layer thickness regulating blade 124 (n) and the developing roller 123 (n) to the apparatus temperature _T in (n) [° C.] When the calculated temperature of the layer thickness regulating blade 124 and the temperature of the developing roller 123 are equal to or lower than the _in- machine temperature T _in (n) [° C.], the current temperature T _B (n) of the layer thickness regulating blade 124 and the developing roller The temperature T _D (n) of 123 is calculated as the temperature of the layer thickness regulating blade 124 and the temperature of the developing roller 123. Thus, by opening the front cover 23 for a long time, it is possible to obtain an appropriate calculation result even when the temperature of the developing cartridge 10 is lower than the previous calculation.

The storage unit 150 is used in the calculation performed by the temperature calculation unit 140, the driving state of the developing roller 123, the open / close state of the rear cover 24, the case of executing single-sided printing and the case of executing double-sided printing, the size of the paper P, and the fan 81. Constants (Q _B , C _B , R _in-B , R _out-B , C _D , R _in-D , R _out-D , R _P- according to each state of the driving state and the state of the fixing device 7. _D , Q _P , C _P ) are stored. Specifically, a map indicating a relationship between a plurality of combinations of each state and a plurality of constants is stored.

In addition, the storage unit 150 includes a nonvolatile memory, and the temperature T _B (n) [° C.] of the layer thickness regulating blade 124 calculated by the temperature calculation unit 140 and the temperature T _{D of the} developing roller 123 are appropriately calculated in the nonvolatile memory. (N) [° C.], and the _in- machine temperature T _in (n) [° C.] and the outside air temperature T _out (n) [° C.] used in the calculation are stored. When the storage unit 150 includes a volatile memory having a circuit that is energized even when the power of the laser printer 1 is turned off, the layer thickness regulation calculated by the temperature calculation unit 140 is included in the volatile memory. temperature _T B of the blade 124 (n) [℃] temperature _T D of the developing roller 123 (n) [℃], and the internal temperature _T in used in calculation (n) [℃] the outside air temperature _{T out} (n ) [° C] may be stored.

When receiving the print job, the print control unit 110 receives the current temperature T _B (n) [° C.] of the layer thickness regulating blade 124 stored in the storage unit 150 and the temperature T _D (n) of the developing roller 123. get the [° C.], the fifth predetermined at least one of which is a first threshold temperature _T B of the current layer thickness regulating blade 124 (n) [℃] temperature _T D of the developing roller 123 (n) [℃] The cooling control is executed when the temperature is higher than T5 [° C.]. Then, the print control unit 110, a fourth both the temperature _T B of the current layer thickness regulating blade 124 (n) [℃] temperature _T D of the developing roller 123 (n) [℃] is a second threshold value When the temperature falls below a predetermined temperature T4 [° C.], the cooling control is stopped. Incidentally, when the temperature _T B of the layer thickness regulating blade 124 (n) [℃] temperature _T D of the developing roller 123 (n) [℃] is, when became less than the second threshold value, falls below a second threshold value Alternatively, the time when it is lower than the second threshold may be set as the time when it falls below the second threshold.

  The fifth predetermined temperature T5 [° C.] is a temperature not higher than the melting point of the toner. The fourth predetermined temperature T4 [° C.] may be the same as the fifth predetermined temperature T5 [° C.], or may be lower than the fifth predetermined temperature T5 [° C.].

  The printing control unit 110 sets the rotation speed V of the developing roller 123 to the first speed V1 [rpm] when the cooling control is not being executed. In the cooling control, the print control unit 110 sets the rotation speed V of the developing roller 123 to a second speed V2 [rpm] that is lower than the first speed V1 [rpm].

  Further, when the cooling control is not being executed, the print control unit 110 sets the conveyance interval D of the paper P to the first interval D1 [s]. In the cooling control, the print control unit 110 sets the conveyance interval D of the paper P to the second interval D2 [s] that is longer than the first interval D1 [s]. Here, the conveyance interval D is a time interval at which a plurality of sheets P are sent to the image forming unit 4 by the sheet feeding unit 3. That is, the conveyance interval D correlates with the number of sheets P conveyed to the image forming unit 4 per unit time.

Next, a specific control operation of the control unit 100 will be described.
As shown in FIG. 3, when the laser printer 1 is powered on, the control unit 100 first performs a cold start determination (S1).

As shown in FIG. 8, when the control unit 100 starts the cold start determination, first, from the detection results of the in-machine temperature sensor SE1 and the outside air temperature sensor SE2, the current in-machine temperature T _in (n) [° C.] and the current It is determined whether the absolute value of the difference between the outside air temperatures T _out (n) [° C.] is equal to or lower than a sixth predetermined temperature T 6 [° C.] (S101).

When it is determined in step S101 that the absolute value of the difference between the current in-machine temperature T _in (n) [° C.] and the current outside air temperature T _out (n) [° C.] is equal to or less than the sixth predetermined temperature T6 [° C.] ( S101, Yes), the control unit 100 sets the current temperature T _B (n) of the layer thickness regulating blade 124 to the current in-machine temperature T _in (n) [° C.] detected by the in-machine temperature sensor SE1, and The temperature T _D (n) of the developing roller 123 is set to the current in-machine temperature T _in (n) [° C.] detected by the in-machine temperature sensor SE1 (S102).

When it is determined in step S101 that the absolute value of the difference between the current in-machine temperature T _in (n) [° C.] and the current outside air temperature T _out (n) [° C.] is not less than or equal to the sixth predetermined temperature T6 [° C.] ( S101, No), the control unit 100 determines that the temperature T _B (n) ′ [° C.] of the layer thickness regulating blade 124 stored in the storage unit 150 is higher than the current in-machine temperature T _in (n) [° C.] Further, it is determined whether or not the temperature T _D (n) ′ [° C.] of the developing roller 123 stored in the storage unit 150 is higher than the current in-machine temperature T _in (n) [° C.] (S103).

In step S103, the temperature T _B (n) ′ [° C.] of the layer thickness regulating blade 124 stored in the storage unit 150 is higher than the current in-machine temperature T _in (n) [° C.], and the storage unit 150 When it is determined that the stored temperature T _D (n) ′ [° C.] of the developing roller 123 is higher than the current in-machine temperature T _in (n) [° C.] (S103, Yes), the control unit 100 performs step S102. The current temperature T _B (n) of the layer thickness regulating blade 124 is set to the current in-machine temperature T _in (n) [° C.] detected by the in-machine temperature sensor SE1, and the current temperature of the developing roller 123 is set. T _D (n) is set to the current in-machine temperature T _in (n) [° C.] detected by the in-machine temperature sensor SE1.

In step S103, the temperature T _B (n) ′ [° C.] of the layer thickness regulating blade 124 stored in the storage unit 150 is higher than the current in-machine temperature T _in (n) [° C.], and the storage unit 150 When it is not determined that the stored temperature T _D (n) ′ [° C.] of the developing roller 123 is higher than the current in-machine temperature T _in (n) [° C.] (S103, No), the control unit 100 The temperature T _B (n) of the current layer thickness regulating blade 124 is set to the temperature T _B (n) ′ [° C.] of the layer thickness regulating blade 124 stored in the storage unit 150, and the current developing roller 123 The temperature T _D (n) is set to the temperature T _D (n) ′ [° C.] of the developing roller 123 stored in the storage unit 150 (S104).

  And the control part 100 complete | finishes a cold start determination after step S102 or step S104.

  As shown in FIG. 3, the controller 100 proceeds to step S <b> 2 and performs a temperature calculation after making a cold start determination. In the present embodiment, the control unit 100 repeatedly performs the control from step S2 to step S7 in a predetermined control cycle.

  As shown in FIG. 4, when the temperature calculation is started, the control unit 100 first determines whether or not the rear cover 24 is open (S201).

In step S201, if it is determined that the rear cover 24 is not open (S201, No), the control unit 100 sets the rear cover open flag _{F C} to zero (S202). On the other hand, in step S201, when it is determined that the rear cover 24 is opened (S201, Yes), the control unit 100 sets the rear cover open flag _{F C} to 1 (S203).

After setting the rear cover open flag _{F C} at step S202 or step S203, the control unit 100, a motor 4A for driving the developing roller 123 determines whether it is being driven (S204).

In step S204, the motor 4A for driving the developing roller 123 is determined to be being driven (S204, Yes), the control unit 100 sets the motor flag _{F M} to 1 (S205), the developing roller 123 is first It is determined whether or not it is rotating at a speed V1 [rpm] (S206).

If it is determined in step S206 that the developing roller 123 is rotating at the first speed V1 [rpm] (S206, Yes), the control unit 100 sets the developing roller speed flag _FV to 1 (S207). On the other hand, in step S206, when the developing roller 123 was determined not to be rotated at a first speed V1 [rpm] (S206, No ), the control unit 100 sets the developing roller velocity flag _{F V} to zero (S208 ).

Step S207 or after setting the developing roller velocity flag _{F V} in step S208, the control unit 100 determines whether there is a print job (S209).

In step S209, if it is determined that there is print job (S209, Yes), the control unit 100 sets the job flag _{F J} to 1 (S210), as shown in FIG. 5, whether or not to execute the double-sided printing Is determined (S211).

If it is determined in step S211 that double-sided printing is not performed, that is, single-sided printing is to be performed (S211, No), the control unit 100 sets the double-sided printing flag _FP to zero (S212) and prints on small-size paper. It is determined whether or not to perform (S213).

In step S213, if it is determined not to print a small size sheets (S213, No), the control unit 100 sets the paper size flag _{F S} to zero (S214). On the other hand, in step S213, when it is determined that the printing on small size sheets (S213, Yes), the control unit 100 sets the paper size flag _{F S} to 1 (S215).

After setting the paper size flag _{F S} at step S214 or step S215, the control unit 100, the flag _F C is set so _{far, F M, F J, F} P, F S, F R, F F1, F F2 Accordingly, the constant is acquired from the storage unit 150 (S216).

After obtaining the constant in step S216, the control unit 100 calculates the current temperature T _B (n) of the layer thickness regulating blade 124 and the current temperature T _D (n) of the developing roller 123 (S217). .

In step S211, when it is determined to execute the double-sided printing (S211, Yes), the control unit 100 sets the duplex printing flag _{F P} to 1 (S218), obtains a constant proceeds to step S216.

Further, as shown in FIG. 4, in step S209, when it is determined that there is no print job (S209, No), the control unit 100 sets the job flag _{F J} to zero (S219), as shown in FIG. 5 In step S216, a constant is acquired.

Then, as shown in FIG. 4, at step S204, the motor 4A for driving the developing roller 123 is determined not to be driven (S204, No), the control unit 100 sets the motor flag _{F M} to zero ( S220), as shown in FIG. 7, it is determined whether or not the fixing device 7 is in a ready state (S221).

In step S221, if the fixing device 7 is determined not to be ready (S221, No), the control unit 100 sets the fuser flag _{F R} to zero (S222). On the other hand, in step S221, if the fixing device 7 is determined to be ready (S221, Yes), the control unit 100 sets the fuser flag _{F R} to 1 (S223).

After setting the fuser flag _{F R} at step S222 or step S223, the control unit 100 determines whether fan 81 is running (S224).

When it is determined in step S224 that the fan 81 is operating (S224, Yes), the control unit 100 sets the fan flag _FF1 to 1 (S225), and whether or not the fan 81 is operating at full speed. Is determined (S226).

If it is determined in step S226 that the fan 81 is operating at full speed (S226, Yes), the control unit 100 sets the fan speed flag _FF2 to 1 (S227). On the other hand, if it is determined in step S226 that the fan 81 is not operating at full speed (S226, No), the control unit 100 sets the fan speed flag _FF2 to zero (S228).

After setting the fan speed flag _{F F2} in step S227 or step S228, the control unit 100, as shown in FIG. 5, to obtain the constant proceeds to step S216.

Further, as shown in FIG. 7, in step S224, if fan 81 is determined not to run (S224, No), the control unit 100 sets the fan flag _{F F1} to zero (S229), FIG. 5 As shown in FIG. 4, the process proceeds to step S216 to obtain a constant.

In step S217, when the current temperature T _B (n) [° C.] of the layer thickness regulating blade 124 and the current temperature T _D (n) [° C.] of the developing roller 123 are calculated, as shown in FIG. The part 100 has an absolute value of the difference between the temperature T _B (n) [° C.] and the in-machine temperature T _in (n) [° C.] of the layer thickness regulating blade 124 obtained in step S217 under the three conditions (1). Between the predetermined temperature T1 [° C.] and the second predetermined temperature T2 [° C.] (2) The temperature T _D (n) [° C.] of the developing roller 123 obtained in step S217 and the in-machine temperature T _in (n) The absolute value of the difference in [° C.] is between the first predetermined temperature T1 [° C.] and the second predetermined temperature T2 [° C.], and (3) the temperature T of the layer thickness regulating blade 124 obtained in step S217 Absolute difference between _B (n) [° C.] and developing roller 123 temperature T _D (n) [° C.] It is determined whether or not all of the values equal to or lower than the third predetermined temperature T3 [° C.] are satisfied (S230).

When it is determined in step S230 that all three conditions are satisfied (S230, Yes), the control unit 100 determines the temperature of the layer thickness regulating blade 124 in the storage unit 150 in the previous calculation used in the next calculation. T _B (n−1) [° C.], the temperature T _D (n−1) [° C.] of the developing roller 123, the previous in-machine temperature T _in (n−1) [° C.], and the outside temperature T _out (n−1) ) [° C.] is updated (S232), and the temperature calculation is terminated.

On the other hand, when it is determined in step S230 that one or more of the three conditions are not satisfied (S230, No), the control unit 100 determines the current temperature T _B (n) of the layer thickness regulating blade 124 as the in-machine temperature sensor. SE1 while the internal temperature _T in the detected (n) [° C.] is the current development temperature _T D of the roller 123 (n) is a machine temperature _T in the apparatus temperature sensor SE1 detects (n) [° C.] ( S231), the process proceeds to step S232, and the data in the storage unit 150 is updated.

  As shown in FIG. 3, after completing the temperature calculation in step S2, the control unit 100 determines whether there is a print job (S3).

In step S3, when it is determined that there is no print job (S3, No), i.e. if the job flag _{F J} is zero, the control unit 100 determines whether or not the front cover 23 is opened (S6).

On the other hand, in step S3, if it is determined that there is print job (S3, Yes), i.e. if the job flag _{F J} is 1, the control unit 100 performs the temperature determination (S4).

As shown in FIG. 9, when the control unit 100 starts temperature determination, first, from the storage unit 150, the current temperature T _B (n) [° C.] of the layer thickness regulating blade 124 and the current temperature of the developing roller 123. T _D (n) [° C.] is acquired (S401).

Then, the control unit 100 determines that the acquired temperature T _B (n) [° C.] of the layer thickness regulating blade 124 is equal to or lower than the fourth predetermined temperature T4 [° C.] and the acquired temperature T _D (n of the developing roller 123 ) It is determined whether or not [° C.] is equal to or lower than the fourth predetermined temperature T4 [° C.] (S402).

In step S402, the acquired temperature T _B (n) [° C.] of the layer thickness regulating blade 124 is equal to or lower than the fourth predetermined temperature T4 [° C.], and the acquired temperature T _D (n) [° C. of the developing roller 123 is obtained. ] Is equal to or lower than the fourth predetermined temperature T4 [° C.] (Yes in S402), the control unit 100 sets the conveyance interval D of the paper P to the first interval D1 [s] and the developing roller 123. The rotational speed V is set to the first speed V1 [rpm] (S404).

In step S402, the acquired temperature T _B (n) [° C.] of the layer thickness regulating blade 124 is equal to or lower than the fourth predetermined temperature T4 [° C.], and the acquired temperature T _D (n) [° C. of the developing roller 123 is obtained. ] Is equal to or lower than the fourth predetermined temperature T4 [° C.] (No in S402), the control unit 100 detects the temperature T _B (n of the layer thickness regulating blade 124 acquired in step S401. ) Whether [° C.] is equal to or lower than the fifth predetermined temperature T5 [° C.], and whether the temperature T _D (n) [° C.] of the developing roller 123 acquired in step S401 is equal to or lower than the fifth predetermined temperature T5 [° C.]. It is determined whether or not (S403).

In step S403, the acquired temperature T _B (n) [° C.] of the layer thickness regulating blade 124 is equal to or lower than the fifth predetermined temperature T5 [° C.], and the acquired temperature T _D (n) [° C. of the developing roller 123 is obtained. ] Is determined to be equal to or lower than the fifth predetermined temperature T5 [° C.] (S403, Yes), the control unit 100 proceeds to step S404 and sets the conveyance interval D of the paper P to the first interval D1 [s]. At the same time, the rotation speed V of the developing roller 123 is set to the first speed V1 [rpm].

On the other hand, in step S403, the acquired temperature T _B (n) [° C.] of the layer thickness regulating blade 124 is equal to or lower than the fifth predetermined temperature T5 [° C.], and the acquired temperature T _D (n) of the developing roller 123 is obtained. When it is determined that the condition that [° C.] is equal to or lower than the fifth predetermined temperature T5 [° C.] (S403, No), the control unit 100 sets the transport interval D of the paper P to the second interval D2 [s]. And the rotation speed V of the developing roller 123 is set to the second speed V2 [rpm] (S405).

  When the conveyance interval D of the paper P and the rotation speed V of the developing roller 123 are determined in step S404 or step S405, the control unit 100 ends the temperature determination.

  As shown in FIG. 3, the controller 100 executes (continues) the printing process after the temperature determination (S5).

  Then, the control unit 100 determines whether or not the front cover 23 is open (S6).

  If it is determined in step S6 that the front cover 23 is not open (S6, No), the control unit 100 returns to step S2 and performs temperature calculation. On the other hand, when it determines with the front cover 23 being open by step S6 (S6, Yes), the control part 100 performs a cover open time process (S7).

  As illustrated in FIG. 10, when the cover opening process is started, the control unit 100 first determines whether or not the front cover 23 is closed (S701).

  If it is determined in step S701 that the front cover 23 is not closed (S701, No), the control unit 100 stands by while continuing the temperature calculation until it is determined that the front cover 23 is closed.

  If it is determined in step S701 that the front cover 23 is closed (S701, Yes), the control unit 100 determines whether or not the developing cartridge 10 is new (S702).

If it is determined in step S702 that the developing cartridge 10 is new (S702, Yes), the control unit 100 detects the current temperature T _B (n) of the layer thickness regulating blade 124 by the outside air temperature sensor SE2. In addition to setting T _out (n) [° C.], the current temperature T _D (n) of the developing roller 123 is set to the outside air temperature T _out (n) [° C.] detected by the outside air temperature sensor SE2 (S703). Then, the control unit 100 determines whether or not the front cover 23 has been opened for 3 minutes or more (S704).

  On the other hand, if it is determined in step S702 that the developing cartridge 10 is not new (S702, No), the control unit 100 proceeds to step S704 and determines whether the front cover 23 has been opened for 3 minutes or more.

When it is determined in step S704 that the front cover 23 has been opened for 3 minutes or more (S704, Yes), the control unit 100 determines that the current temperature T _B (n) [° C.] of the layer thickness regulating blade 124 is the in-machine temperature T _in. It is determined whether or not the current temperature T _D (n) [° C.] of the developing roller 123 is higher than (n) [° C.] and greater than the _in- machine temperature T _in (n) [° C.] (S705).

In step S705, the current temperature T _B (n) [° C.] of the layer thickness regulating blade 124 is greater than the _in- machine temperature T _in (n) [° C.], and the current temperature T _D (n) [ [° C.] is determined to be larger than the _in- machine temperature T _in (n) [° C.] (S705, Yes), the control unit 100 determines the current temperature T _B (n) of the layer thickness regulating blade 124 by the in-machine temperature sensor SE1. The detected in-machine temperature T _in (n) [° C.] and the current temperature T _D (n) of the developing roller 123 are set to the in-machine temperature T _in (n) [° C.] detected by the in-machine temperature sensor SE1 (S706). ).

On the other hand, if it is determined in step S704 that the front cover 23 has not been opened for 3 minutes or longer (S704, No), the control unit 100 ends the cover opening process. In step S705, the current temperature T _B (n) [° C.] of the layer thickness regulating blade 124 is larger than the _in- machine temperature T _in (n) [° C.], and the current temperature T _D (n of the developing roller 123). When the condition that [° C.] is larger than the _in- machine temperature T _in (n) [° C.] is not satisfied (No in S705), the control unit 100 ends the cover opening process.

  As shown in FIG. 3, when the cover opening process is completed, the control unit 100 returns to step S2 to perform temperature calculation.

The operation and effect of the laser printer 1 configured as described above will be described.
When the developing roller 123 is rotated by a warming operation performed during the printing operation or after the front cover 23 is closed and before the printing operation, the temperature of the developing roller 123 and the layer thickness regulating blade 124 rises due to friction or the like. Further, when the fixing device 7 is in the ON state, the developing cartridge 10 is warmed by the heat from the heating unit 71.

  In the laser printer 1, the temperature and layer thickness of the developing roller 123 based on the in-machine temperature detected by the in-machine temperature sensor SE 1, the outside air temperature detected by the outside air temperature sensor SE 2, and the driving state of the developing roller 123 by the control unit 100. The temperature of the regulating blade 124 is calculated, and when the temperature of the developing roller 123 and the temperature of the layer thickness regulating blade 124 become higher than the fifth predetermined temperature T5 during the printing operation, the cooling control is executed. As a result, the cooling control is appropriately executed, so that the deterioration of the toner can be suppressed.

  In particular, in this embodiment, the cooling process is performed when at least one of the temperature of the developing roller 123 and the temperature of the layer thickness regulating blade 124 becomes higher than the fifth predetermined temperature T5. Even when the execution of the cooling control is determined based on only one of the temperatures of the blades 124, the cooling control can be executed at an appropriate timing.

  Since the control unit 100 changes the constants used in the calculation of the temperature of the developing roller 123 and the temperature of the layer thickness regulating blade 124 according to the driving state of the developing roller 123, the development due to the difference in the driving state of the developing roller 123 is performed. The calculation can be performed in consideration of the difference in temperature change of the cartridge 10. Thereby, cooling control can be performed appropriately.

  In addition, when only the cooled paper P is supplied to the process cartridge 6 as in the case of executing single-sided printing, and when the paper P heated through the fixing device 7 is used in the case of executing double-sided printing. Although there is a difference in the temperature change of the developing cartridge 10 depending on whether it is supplied to the process cartridge 6, the control unit 100 determines the constant used in the calculation of the temperature of the developing roller 123 and the temperature of the layer thickness regulating blade 124 on one side. Since the case of executing printing and the case of executing double-sided printing are changed, the calculation can be performed in consideration of the difference in temperature change of the developing cartridge 10 between the case of executing single-sided printing and the case of performing double-sided printing.

  When printing on small size paper, the heat capacity of the paper P is small, so the amount of heat transferred from the developing cartridge 10 to the paper P is smaller than when printing on the paper P larger than the small size paper, and the developing cartridge 10 Temperature rises easily. In the present embodiment, the control unit 100 prints the constants used in the calculation of the temperature of the developing roller 123 and the temperature of the layer thickness regulating blade 124 on the small size paper and on the paper P larger than the small size paper. Therefore, the calculation can be performed in consideration of the difference in the temperature change of the developing cartridge 10 due to the difference in the size of the paper P.

  In addition, since the control unit 100 changes the constants used in the calculation of the temperature of the developing roller 123 and the temperature of the layer thickness regulating blade 124 according to the operating state of the fan 81, the development due to the difference in cooling effect in the machine by the fan 81 is developed. The calculation can be performed in consideration of the difference in temperature change of the cartridge 10.

  Since the control unit 100 changes the constants used in the calculation of the temperature of the developing roller 123 and the temperature of the layer thickness regulating blade 124 according to the operating state of the fixing device 7, the developing cartridge 10 depending on the operating state of the fixing device 7. It is possible to calculate in consideration of the difference in temperature change.

  In this embodiment, since the temperature sensor is not provided in the process cartridge 6, the cost of the process cartridge 6 can be suppressed.

  Further, since the in-machine temperature sensor SE1 is disposed at a position between the fixing device 7 and the developing roller 123 in the housing 2, the in-machine temperature sensor SE1 generates heat flowing from the fixing device 7 toward the developing cartridge 10. Can be measured.

  Since the outside air temperature sensor SE2 is disposed so as to face the air inlet 82, the outside air temperature sensor SE2 can appropriately measure the outside air temperature taken into the housing 2.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment. About a concrete structure, it can change suitably in the range which does not deviate from the meaning of this invention.

  In the embodiment, in the cooling control, the control unit 100 makes the conveyance interval D of the paper P longer than when the cooling control is not executed, and the rotation speed V of the developing roller 123 is lower than when the cooling control is not executed. Although the speed is set, the cooling control is not limited to this. For example, the control unit 100 may stop the developing roller 123 in the cooling control.

  Moreover, the control part 100 may make the speed of the fan 81 larger in the cooling control than when the cooling control is not executed.

  And the memory | storage part 150 may memorize | store the several 2nd space | interval D2 according to the kind (one-sided printing, double-sided printing, paper size) of printing jobs, and 2nd speed V2. In the cooling control, the control unit 100 may switch the second interval D2 and the second speed V2 according to the type of print job (single-sided printing, double-sided printing, paper size) and the outside air temperature.

In the embodiment, the print control unit 110 of the control unit 100 has the first threshold value in which at least one of the current temperature T _B (n) of the layer thickness regulating blade 124 and the temperature T _D (n) of the developing roller 123 is the first threshold value. 5 When the temperature is higher than the predetermined temperature T5, the cooling control is executed, and both the current temperature T _B (n) of the layer thickness regulating blade 124 and the temperature T _D (n) of the developing roller 123 are second threshold values. 4 The configuration is such that the execution of the cooling control is stopped when the temperature falls below the predetermined temperature T4, but the configuration of the control unit is not limited to this. For example, the control unit switches the first threshold value and the second threshold value according to the type of print job (single-sided printing, double-sided printing, paper size) and the outside air temperature, and the first threshold value and the second threshold value are switched to the current layer thickness regulating blade. The temperature T _B (n) 124 may be compared with the temperature T _D (n) of the developing roller 123.

Furthermore, the control unit 100, the temperature _T D of the temperature _T B (n) and the developing roller 123 of the current layer thickness regulating blade 124 (n), compared with a plurality of threshold values including a first threshold value, the current thickness When at least one of the temperature T _B (n) of the regulating blade 124 and the temperature T _D (n) of the developing roller 123 exceeds a higher threshold, the conveyance interval D of the paper P is set to a larger interval, or the developing roller 123 Alternatively, the rotation speed V may be made smaller. Specifically, the control unit 100 determines whether or not at least one of the current temperature T _B (n) of the layer thickness regulating blade 124 and the temperature T _D (n) of the developing roller 123 is higher than the fifth predetermined temperature T5. When the temperature is exceeded, the conveyance interval D of the paper P may be set to be larger than the second interval D2, or the rotation speed V of the developing roller 123 may be set to a rotation speed smaller than the second speed V2 or zero. .

  In the above-described embodiment, the laser printer 1 is configured such that the reading unit 30 detects whether the developing cartridge 10 is new or not by reading information of the IC 10A mounted on the developing cartridge 10. The configuration for detecting whether or not the developing cartridge 10 is new is not limited to this. For example, the laser printer 1 and the developing cartridge 10 may include a new article detection mechanism that operates in conjunction with the driving of the developing cartridge 10. As an example, the developing cartridge 10 has a detected member that irreversibly moves from a new position when the developing cartridge 10 is attached to the casing 2, and the casing 2 is an exchange detection that detects the position of the detected member. A sensor 65 may be provided.

  In the embodiment, the control unit 100 switches the constant for calculating the temperature of the process cartridge 6 between single-sided printing and double-sided printing, but the configuration of the control unit is not limited to this. For example, the control unit switches the constant for calculating the temperature of the process cartridge 6 between when printing on the first side of the paper P and when printing on the second side of the paper P. May be.

  In the embodiment, the heating unit 71 including the fixing belt and the nip plate is exemplified, but the configuration of the heating unit is not limited thereto. For example, the heating unit may have a configuration mainly including a heating roller and a halogen heater disposed inside the heating roller.

DESCRIPTION OF SYMBOLS 1 Laser printer 2 Housing | casing 6 Process cartridge 7 Fixing device 23 Front cover 71 Heating part 82 Inlet 123 Developing roller 124 Layer thickness control blade 150 Storage part P Paper SE1 In-machine temperature sensor SE2 Outside air temperature sensor

Claims (15)

A developing unit having a developing roller and a layer thickness regulating blade in contact with the developing roller, and forming a developer image on the sheet;
A fixing device having a heating section for heating the sheet;
A housing for housing the developing unit and the fixing device;
An in-machine temperature sensor that detects an in-machine temperature that is the temperature in the housing;
An outside air temperature sensor that detects outside air temperature that is outside the housing;
A storage unit for storing a constant according to the driving state of the developing roller;
A control unit,
The constant includes a calorific value of the layer thickness regulating blade,
The control unit calculates the temperature of the developing roller and the temperature of the layer thickness regulating blade as the temperature of the developing unit based on the internal temperature, the outside air temperature, and the driving state of the developing roller, and the developing roller When at least one of the temperature of the layer thickness and the temperature of the layer thickness regulating blade is higher than a predetermined temperature, the cooling control is executed ,
The formula for calculating the temperature of the developing roller includes a term including the internal temperature and a term including the outside air temperature,
The equation for calculating the temperature of the layer thickness regulating blade includes a term including the in-machine temperature, a term including the outside air temperature, and a term including the calorific value which is the constant.
The control unit acquires the heat generation amount from the storage unit according to the driving state of the developing roller, and calculates the temperature of the layer thickness regulating blade using the acquired heat generation amount. Forming equipment. The controller is
Performing single-sided printing for printing on one side of the sheet, and double-sided printing for feeding the sheet printed on one side and heated by the fixing device to the developing unit and printing on both sides of the sheet,
The constants are depending on each case of executing the double-sided printing with the case of executing the one-side printing,
The image according to claim 1 , wherein the control unit obtains the constant from the storage unit and calculates the temperature of the developing unit depending on whether single-sided printing or double-sided printing is performed. Forming equipment. The control unit calculates a differential temperature, which is a temperature change of the developing unit from the previous calculation to the present, at predetermined intervals based on the internal temperature, the outside air temperature, and the driving state of the developing roller. 3. The image forming apparatus according to claim 1, wherein a sum of the obtained differential temperature and the temperature of the developing unit calculated last time is set as a current temperature of the developing unit. 2. The control unit according to claim 1, wherein when the difference between the obtained temperature of the developing unit and the temperature in the apparatus is not within a predetermined range, the temperature of the developing unit is set as the temperature in the apparatus. 4. The image forming apparatus according to any one of items 3 . The housing has an air inlet for taking in air from the outside,
The ambient temperature sensor, an image forming apparatus according to any one of claims 1 to 4, characterized in that it is arranged facing the intake port of the casing. The internal temperature sensor, the image forming apparatus according to any one of claims 5 being disposed claims 1, wherein a position between the housing of the fixing device and the developing roller . Wherein the control unit, wherein in the cooling control, the rotational speed of the developing roller, to any one of claims 1 to claim 6, characterized in that the lower rate than when not performing the cooling control Image forming apparatus. Wherein the control unit is configured in the cooling control, the sheet conveyance interval, the image forming apparatus according to any one of claims 1 to 7, characterized in that longer than without running the cooling control . The control unit executes the cooling control when the temperature of the developing unit exceeds a first threshold, and after executing the cooling control, when the temperature of the developing unit falls below a second threshold, the image forming apparatus according to any one of claims 8 to stop the execution of the cooling control from claim 1, wherein. The image forming apparatus according to claim 9 , wherein the control unit stops driving of the developing roller in the cooling control. When the difference between the temperature of the developing roller and the temperature of the layer thickness regulating blade is not within the second predetermined range, the control unit determines the temperature of the developing roller and the temperature of the layer thickness regulating blade as the in-machine temperature. The image forming apparatus according to claim 1 , wherein the image forming apparatus is an image forming apparatus. With memory,
The controller is
The calculated temperature of the developing unit is stored in the memory,
When the image forming apparatus is turned on, if the internal temperature is lower than the temperature of the developing unit stored in the memory, the current temperature of the developing unit is set to the same value as the internal temperature. When the internal temperature is equal to or higher than the temperature of the developing unit stored in the memory, the current temperature of the developing unit is set as the temperature of the developing unit stored in the memory. The image forming apparatus according to any one of claims 1 to 11 . The controller is
13. The image forming apparatus according to claim 12 , wherein when the difference between the in-machine temperature and the outside air temperature is equal to or less than a predetermined value, the current temperature of the developing unit is set to the same value as the in-machine temperature. . The developing unit is configured to be detachable from the housing,
The control unit according to any one of claims 1 to 13 , wherein when detecting that the developing unit has been replaced, the control unit sets the current temperature of the developing unit to the outside air temperature. The image forming apparatus described. A cover for opening and closing a part of the housing;
When the calculated temperature of the developing unit is higher than the in-machine temperature when the cover is closed after being opened for a predetermined time or more, the control unit sets the current temperature of the developing unit to the in-machine temperature. set the temperature of the calculated the developing unit, if the at internal temperature below the preceding claims, characterized in that the temperature of the developing unit which calculates the current temperature of the developing unit of claim 14 The image forming apparatus according to claim 1.

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