JP2019133100A - Image formation apparatus - Google Patents

Abstract

To reduce power consumed by cooling means while suppressing decrease in productivity.SOLUTION: An image formation apparatus comprises: a process cartridge 120 and a fixation ejection sensor 109 which heat up along with a printing operation; a fan 140 for cooling the members; temperature sensors 400, 500 detecting the temperatures of the members; and a CPU 201 controlling the driving of the fan 140. Based on element temperature Tdetected by the temperature sensors 400, 500 at time when the printing operation started and printing operation time t, the CPU 201 determines a control parameter for driving the fan 140 so that element temperature T at time twhen the printing operation is completed does not exceed temperature T.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an image forming apparatus having a cooling unit.

  Various control methods for realizing power saving by omitting unnecessary operation of the cooling means have been proposed as control of the cooling means provided in the image forming apparatus or the like. For example, there is a control in which the cooling operation is started when the printing operation is started and the cooling unit is stopped when a time corresponding to the number of printed sheets has elapsed after the printing operation is finished (for example, see Patent Document 1). By performing such control, power saving is realized as compared with the conventional control in which the cooling unit is stopped when a fixed time has elapsed after the printing operation is completed.

  Further, the temperature of the element on the electrical component is estimated for each of various conditions such as the environment where the image forming apparatus is placed and the set use mode, and the cooling means only when the estimated temperature exceeds a predetermined temperature. There is a control to operate (see, for example, Patent Document 2). This control realizes power saving compared to the conventional control in which the control values are uniformly set. Here, the control value is uniformly set so that the temperature of the element on the electrical component is below the upper limit of the recommended operating temperature in the most severe environment set as the use limit of the image forming apparatus and in any use mode. It is a set value. Compared with the control in which the cooling unit is stopped when the time corresponding to the number of printed sheets has elapsed, there is a period during which the cooling unit is not operated during the printing operation, so that the control method achieves further power saving.

Japanese Patent Laid-Open No. 11-184355 JP 2003-076251

  In the control of operating the cooling unit based on the estimated temperature, if the cooling unit is operated during the printing operation, a great effect is exhibited for an image forming apparatus having an element in which the temperature of the element on the electrical component is lowered. However, even if the cooling means is operated during the printing operation, the image forming apparatus having an element that does not prevent the temperature increase only by decreasing the temperature rise rate of the element cannot be sufficiently exhibited. In the case of such an element, since the temperature of the element will eventually exceed the upper limit of the recommended operating temperature, it is necessary for the image forming apparatus to prevent the temperature of the element from increasing by stopping the printing operation or reducing the throughput. There is. When the image forming apparatus shifts to a mode in which the temperature rise of the element is suppressed, the productivity may be reduced.

  The present invention has been made under such circumstances, and an object of the present invention is to reduce the power consumption by the cooling means while not reducing the productivity.

  In order to solve the above-described problems, the present invention has the following configuration.

  (1) An image forming apparatus that forms an image on a recording material, a member that increases in temperature with a printing operation, a cooling unit that cools the member, a detection unit that detects the temperature of the member, Control means for controlling the drive of the cooling means, the control means based on the temperature of the member detected by the detection means when the printing operation is started and the time required for the printing operation A parameter for driving the cooling means is determined so that the temperature of the member when the printing operation is finished does not exceed a predetermined temperature.

  According to the present invention, it is possible to reduce the power consumption by the cooling means while not reducing the productivity.

Schematic cross-sectional view of image forming apparatuses of Examples 1 and 2 The graph which shows the temperature change of the element during the printing of Examples 1 and 2 Block diagram of control system of Examples 1 and 2 Flowchart showing fan drive control according to the first embodiment. The figure explaining the temperature change of the element of Example 1, and the drive and stop timing of a fan The figure explaining the subject of Example 2 The figure explaining the temperature change of the element of Example 2, and the drive and stop timing of a fan 7 is a flowchart showing fan drive control according to the second embodiment. Flowchart showing fan drive control of Embodiment 3

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail by way of examples with reference to the drawings.

[Image forming apparatus]
FIG. 1 is a schematic sectional view of an image forming apparatus 100 according to the first embodiment. In FIG. 1, a photosensitive drum 122, which is a photosensitive member, is an organic photosensitive member, an amorphous silicon photosensitive member, or the like, and is rotationally driven in a clockwise direction at a predetermined peripheral speed (process speed). The peripheral surface of the photosensitive drum 122 is uniformly charged to a predetermined polarity and potential by the charging roller 123. The laser beam output from the laser optical box 108 is irradiated onto the charging surface of the photosensitive drum 122 by changing the optical path by the reflection mirror 107, thereby performing scanning exposure and an electrostatic latent image corresponding to image information. Is formed. The laser beam is modulated (on / off converted) in accordance with a time-series electric digital pixel signal of target image information input from an image signal generator (not shown) such as an image reading device or a computer. A developing roller 121 as a developing unit supplies toner in the toner container 124 to the electrostatic latent image formed on the photosensitive drum 122 (on the photosensitive member), and is formed corresponding to the target image. The electrostatic latent image is developed as a toner image which is a developer image. Here, the developing roller 121, the photosensitive drum 122, the charging roller 123, the toner container 124, and the cleaning device 125 are housed in one process cartridge (hereinafter referred to as a cartridge) 120. The cartridge 120 is configured to be detachable from the image forming apparatus 100, and the entire cartridge 120 can be replaced. Further, the members in the cartridge 120 function as image forming means.

  Next, one sheet of recording paper P is fed from a sheet feeding cassette 151 by a sheet feeding roller 102 and conveyed by a conveying roller 103 and a registration roller (hereinafter referred to as a registration roller) 104, and is conveyed to a photosensitive drum 122. Sent in. The paper presence sensor 101 is used to detect that the paper P is placed in the paper feed cassette 151. As a result, the toner image formed on the photosensitive drum 122 is transferred onto the paper P by the transfer roller 106 serving as transfer means. The transfer roller 106 transfers a toner image from the photosensitive drum 122 to the paper P by supplying a charge having a polarity opposite to that of the toner from the back surface of the paper P. Note that the image forming apparatus 100 includes one sheet feeding cassette 151 as a sheet feeding port, but may include a plurality of sheet feeding cassettes and a manual feed tray, or a large capacity connected as an optional apparatus. The configuration may be such that the paper P is fed from the paper feed port. When there are a plurality of paper feed ports (for example, paper feed port 1, paper feed port 2, etc.), one of the paper feed ports is designated during printing.

  The sheet P on which the toner image has been transferred is separated from the photosensitive drum 122 and sent to a heat fixing device 130 as a fixing unit, and an unfixed toner image is transferred onto the sheet P by a heater 132, a fixing film 133, and a pressure roller 134. It is fixed on (on the recording material). The thermistor 131 detects the temperature of the heater 132, and the detection result of the thermistor 131 is used to control the thermal fixing device 130 to a temperature suitable for the fixing process of the paper P. The sheet P carrying the fixed toner image is conveyed by the discharge roller 110 and the FD roller 111 and discharged to the tray 112. Here, the normal conveyance of the paper P is confirmed by the top sensor 105 provided on the conveyance path and the fixing discharge sensor 109 which is a recording material detection unit for detecting the paper P subjected to the fixing process. . Each sensor is composed of, for example, a photo interrupter and a flag installed so as to block its optical path, and the paper P defeats the flag to secure the optical path to the photo interrupter. Can be confirmed. The image forming apparatus 100 has a single tray 112 as a discharge port. However, a plurality of trays may be provided, and a discharge port through which the post-processed paper P (or paper bundle) is discharged from a post-processing device that performs various post-processing connected as an optional device. The structure which has this may be sufficient. When there are a plurality of outlets (for example, outlet 1, outlet 2, etc.), one of the outlets is designated during printing.

  Further, the image forming apparatus 100 is equipped with a fan 140 as a cooling unit. The fan 140 cools a flag (hereinafter referred to as a sensor flag) of the cartridge 120 and the fixing discharge sensor 109 which are elements and members (hereinafter referred to as elements) that increase in temperature with an image forming operation. The image forming apparatus 100 may have one element or a plurality of elements. If these elements are not sufficiently cooled and the temperature continues to rise, the parts may be deformed. If the parts are deformed, the image forming apparatus 100 may not be able to draw an accurate image, or may not be able to confirm whether or not the paper P has passed through the discharge unit. The target to be cooled may be a photo interrupter of the fixing discharge sensor 109. Since the amount of light output changes when the temperature of the photo interrupter increases, in this case as well, there is a possibility that it may not be possible to confirm whether or not the paper P has passed through the discharge section.

  In the vicinity of the cartridge 120, a temperature sensor 400, which is a detecting means for detecting the temperature of the cartridge 120, is provided. The temperature sensor 400 detects the temperature of the cartridge 120 during the printing operation. Further, a temperature sensor 500 that is a detection unit that detects the temperature of the sensor flag of the fixing discharge sensor 109 is provided in the vicinity of the fixing discharge sensor 109. If the image forming apparatus 100 has an environmental sensor (not shown) that detects temperature and humidity, the following may be performed. For example, when there is a correlation between the temperature detected by the environmental sensor and the temperature of the sensor flag of the cartridge 120 or the fixing / discharging sensor 109, the temperature of these elements may be detected based on the detection result of the environmental sensor. .

[Relationship between fan operation and element temperature]
FIG. 2 is a graph showing the temperature change of the cartridge 120 in the case where the cooling by the fan 140 is not performed during the printing operation and in the case where the cooling is performed. FIG. 2 shows time [min (min)] on the horizontal axis and element temperature (hereinafter referred to as element temperature) T [° C.] on the vertical axis. Moreover, the graph of A shows the case where cooling by the fan 140 was not performed, and the graph of B shows the case where cooling by the fan 140 was performed. In FIG. 2, the intercept of each graph indicates the element temperature when the printing operation is started (at the start of the printing operation), and the upper limit of the recommended operation temperature of the element is indicated by a broken line. When the cooling by the fan 140 is not performed, the temperature of the cartridge 120 rapidly increases, and although not shown in the figure, when the upper limit of the recommended operating temperature is exceeded, the heat dissipation amount and the heat generation amount become thermal equilibrium and the temperature increase stops.

On the other hand, when the cooling by the fan 140 is performed, the temperature of the cartridge 120 rises relatively slowly compared to the case where the cooling is not performed. If a certain amount of time elapses even while the fan 140 is being driven, the temperature of the cartridge 120 exceeds the upper limit of the recommended operating temperature at time _t01 , and then reaches thermal equilibrium. Although not shown in FIG. 2, a similar temperature rise curve is drawn for the sensor flag of the fixing discharge sensor 109 which is an example of the element.

[Block diagram of image forming apparatus]
FIG. 3 is a block diagram of a control system of the image forming apparatus 100. The image forming control unit 200 includes a CPU 201 that is a control unit that controls the entire image forming apparatus 100, a ROM 202 that stores a control program, a RAM 203 that stores data, and the like. The CPU 201 can communicate with a controller unit 300 described later via the video interface control circuit 204. The CPU 201 can also control the fan 140 via the fan control circuit 205. The CPU 201 determines the temperature of the cartridge 120 based on the result detected by the temperature sensor 400. The CPU 201 determines the temperature of the sensor flag of the fixing discharge sensor 109 based on the result detected by the temperature sensor 500.

  The CPU 201 has a timer (not shown) and can also measure time using the timer. Here, an example of one fan 140 will be described. However, a plurality of fans 140 may be mounted. When a plurality of fans are mounted, it is possible to apply the fan drive control of the present invention to only some fans, or apply the fan drive control of the present invention to all fans. Is also possible.

  The controller unit 300 includes a CPU 301 that controls the entire controller unit 300, a ROM 302 that stores a control program, a RAM 303 that stores data, and the like. The controller unit 300 is connected to a device such as an image reading device or a computer (not shown) and the image formation control unit 200 via a video interface control circuit 304. The controller unit 300 outputs job information and print instructions to the image formation control unit 200 via the video interface control circuit 304. Here, the job information includes, for example, the number of prints, information about single-sided printing or double-sided printing, designation of a print mode, designation of a paper feed port and a discharge port (hereinafter referred to as a supply / discharge port), and the like.

Before describing specific processing performed by the image formation control unit 200 in the first embodiment, terms necessary for description will be described. A mode in which a printing operation is stopped or a measure such as a reduction in throughput is performed in order to suppress the temperature rise of the element is hereinafter referred to as a temperature rise suppression mode. Here, the throughput refers to the number of sheets of paper P on which an image is formed per minute.
Temperature T _max : A threshold value (temperature) used for determination to shift to the temperature rise suppression mode.
It is set lower than the upper limit of the recommended operating temperature (temperature T _max <the upper limit temperature of the recommended operating temperature). When the image forming control unit 200 determines that the element temperature T has reached the temperature _Tmax , the process _proceeds to the temperature rise suppression mode, and measures such as stopping the printing operation or reducing the throughput are performed. This prevents the element from exceeding the upper limit of the recommended operating temperature.
Temperature T _m : Target value (temperature) for controlling so as not to exceed temperature T _max .
Specifically, a target value (temperature) for controlling the estimated temperature of the element so as not to exceed the temperature T _max after the printing operation is completed. It is set lower than the temperature T _max with a margin (T _m <T _max ).

[Fan drive control]
Specific processing performed by the image formation control unit 200 according to the first exemplary embodiment will be described with reference to FIGS. 4 and 5. When the controller unit 300 transmits job information and a print instruction to the image formation control unit 200 based on information from an image reading apparatus, a computer, or the like, the CPU 201 performs processing after step 401 (hereinafter referred to as S) 401 and subsequent steps. Start.

S401 in CPU201, based on the job information received from the controller unit 300, calculates the printing operation time _{t p.} Various parameters necessary for the calculation of the print operation time _{t p} (e.g., throughput, printing speed, etc.) is CPU201 may be stored in advance in the ROM 202 shall be used to calculate reads the information from the ROM 202.

(Calculation of the print operation time _{t p)}
Here, as an example of job information, a job having the conditions “number of prints N”, “printing speed V”, “single-sided printing”, and “feed from sheet feeding port 1 and eject to ejection port 1” is received. shows the method of calculating the printing operation time t _p when performing printing. The CPU 201 reads the throughput Th [sheets / min] of single-sided printing that feeds the paper P from the paper feed port 1 at the print speed V and discharges it to the discharge port 1 from the ROM 202, and calculates Equation (1).
t _p = N / Th [min] Formula (1)
However, the calculation method using Formula (1) is an example, and is not limited thereto.

Return to the description of the flowchart. In step S <b> 402, the CPU 201 acquires the element temperature T _s of the element (here, the cartridge 120) when the printing operation is started from the temperature sensor 400, for example. In step S403, the CPU 201 stops the fan 140, which is a parameter (hereinafter referred to as a control parameter) for controlling the fan 140, based on the element temperature T _s and job information when the printing operation is started (hereinafter referred to as a control parameter). _Tf ) (referred to as stop time).

(Fan of stop time _t f)
Figure 5 is a diagram for explaining a method for determining the stop time t _f of the fan 140. In FIG. 5, (i) shows time [min] on the horizontal axis and element temperature T [° C.] on the vertical axis. In (i), the element temperature T _s when the printing operation is started, the target temperature T _m , and the temperature T _max that is a threshold used for determination of the temperature rise suppression mode transition are indicated by broken lines. (Ii) shows the state (printer state) of the image forming apparatus 100, and is in the print state while the print operation is being executed, and shifts to the standby state when the print operation is completed at time _tpf . Print operation time _{t p} is the time from the time 0 to time _{t pf.} (Iii) shows the operation of the fan 140, which is “ON” when the fan 140 is operating, and “OFF” when the fan 140 is stopped.

Stop time t _f is the element temperature T at time t _pf even printing operation has been completed is stopped in the middle of the printing operation of the fan 140 is a time that does not exceed the temperature T _m. Stored stop time t _f is the element temperature T _s at which printing operation is _started, the printing operation time t _p, is obtained in advance experimentally depending on the printing speed V, and ROM202 as these were associated table Has been. CPU201 by referring to the ROM202 table, the element temperature _{T s} at which printing operation is started, the printing operation time _{t p,} selects an appropriate stop time _{t f} from the table printing speed V as an index.

Return to the description of the flowchart. S404 in CPU201 is subject to all the cooling elements (hereinafter, referred to as target device) it determines whether to determine the stop time _{t f} of. S404 in CPU201, when it is determined that not decided stop time _{t f} for all target devices, the process returns to S402. CPU201 determines stop time _{t f} of the following elements (the sensor lever of the fixing discharge sensor 109 in this case). S404 in CPU201, when it is determined that determines the stop time _{t f} of all target devices, the process proceeds to S405. CPU201 is stored in a RAM203 in association with each stop time _{t f} of the resulting fan 140 for each subject element and each target element.

In S405 CPU 201 is in the stop time _{t f} of the fan 140 of each target device determined in S403, selects the stop time _{t f} of the driving time of the fan 140 is the longest. By selecting a stop time t _f in this way, prevent exceeding the temperature T _max is a threshold temperature of the whole target device enters the heating suppression mode. CPU201 starts the printing operation in S406 and later, controls the fan 140 in the printing based on the selected stop time _{t f.}

In step S406, the CPU 201 starts a printing operation. In step S407, the CPU 201 starts measurement of an elapsed time until the fan 140 is stopped by using a timer (not shown). In step S <b> 408, the CPU 201 starts driving the fan 140. S409 in CPU201 refers to the timer and determines if the stop time _{t f} selected in S405. S409 in CPU201, when it is determined that not in the stop time _{t f,} the processing returns to S409, and continues the driving of the fan 140 until the stop time _{t f.} S409 in the CPU201 is, if it is determined that it is to stop time _{t f,} the process proceeds to S410. In step S410, the CPU 201 stops the fan 140 without waiting for the end of the printing operation. Compared with the case where the fan 140 is stopped when the printing operation is finished (time t _{pf in} FIG. 5), the fan 140 is stopped earlier by the time Δt shown in FIG.

As shown in FIG. 5I, since the fan 140 is stopped during the printing operation, the element temperature T rises more rapidly than when the fan 140 is driven. However, since the fan 140 is stopped so as not to exceed the target temperature T _m at the end of printing (time t _pf ), the element temperature T does not exceed the temperature T _max that is the threshold value for entering the temperature increase suppression mode. . In other words, the upper limit of the recommended operating temperature of the device is not exceeded. This is true for all the elements of interest. This is because the driving time of the fan 140 is selecting the longest stop time t _f. In other words, the control parameter of the element that reaches the upper limit of the recommended operating temperature earliest is adopted. Furthermore, power consumption corresponding to the time Δt (FIG. 5) during which the operation of the fan 140 is stopped can be suppressed. Further, since the fan 140 is stopped before the printing is finished, the operation sound (such as the driving sound of the fan 140) that the user feels when approaching the image forming apparatus 100 to pick up the paper P after the printing is reduced. You can also. In the first embodiment, the electrophotographic image forming apparatus 100 has been described as an example. However, the present invention is not limited to the electrophotographic image forming apparatus 100 and can be applied to an apparatus having a cooling unit.

  As described above, according to the first embodiment, it is possible to reduce the power consumption by the cooling unit while not reducing the productivity.

  When the printing operation is started continuously after the printing operation is finished, the temperature rising suppression mode may be shifted depending on the element temperature T, the heat dissipation rate of the element, and the printing operation time. Such a case will be described with reference to FIG. FIG. 6 is a diagram similar to FIG. 5, and (i) to (iii) correspond to (i) to (iii) of FIG.

In FIG. 6A, as described in the first embodiment, the element temperature Ts at the start of the printing operation, the printing operation time t _p , and the printing speed are selected from the table experimentally obtained in advance stored in the ROM 202. Appropriate control parameters are selected using V as an index. However, in the second embodiment, there are two types of control parameters for the fan 140, the time when the fan 140 starts to be driven (hereinafter referred to as the drive time) _tf1 and the stop time _tf2 . According to the control parameters of the fan 140, the CPU 201 stops the fan 140 immediately after the printing operation is started, and drives the fan 140 when the driving time _tf1 is reached. Furthermore, the CPU 201 stops the fan 140 again when the stop time _tf2 is reached.

The control parameter of the fan 140 is a value obtained experimentally in advance so that the element temperature T _s does not exceed the temperature T _m when the printing operation ends (time t _pf ). For this reason, the operating time of the fan 140 can be reduced and the element temperature T _s can be suppressed to the temperature T _m or less. Up to this point, only the drive time t _f1 is added to the first embodiment, and the outline of the processing is the same as that described in the first embodiment.

Next, a case where another print job is transmitted from the controller unit 300 to the image formation control unit 200 at time t _s ′ while the same printing operation as that of the first embodiment is being performed is illustrated in FIG. ). When the operation of the fan 140 during the first print job is controlled as described above, the element temperature T is at the temperature T _m at the stage where the first print job is completed (time t _pf ). For this reason, even if an appropriate control parameter is selected again at time t _pf , the element temperature T is inherently high, so that depending on the time required for the next print job, the temperature T _max may be exceeded before the next print operation is completed. There is. 'Beyond the temperature _{T max} in, CPU 201, the time _{t m'} element temperature T the time _{t m} will migrate with the Atsushi Nobori suppression mode, the productivity of up to time _{t pf} 'that all print jobs completed It will decline.

[Fan drive control]
Therefore, in the second embodiment, a control method for preventing the temperature rise suppression mode from entering as much as possible even when the printing operation is started after the printing operation is completed will be described with reference to FIGS. 7 and 8. The processing of the image formation control unit 200 when the first print job is transmitted to the image formation control unit 200 is the same as that described in the first embodiment. However, the control parameters of the fan 140 and two drive time as described above _{t f1} and stop time _{t f2.}

FIG. 7 is a graph similar to FIG. In (i), the graph when the control of the second embodiment is performed is indicated by a solid line, and the graph when the control of the second embodiment is not performed is indicated by a broken line. Round frame shown in FIG. 7 (a) is an enlarged view of the time t _s' neighborhood that has received the next print job to be executed sequentially. CPU201 is driving time _{t f1} decided for the first print job, where that controlled the fan 140 at the stop time _{t f2} (control parameter), to receive the next print job at a time _{t s'.} The CPU 201 interrupts the process of the flowchart of FIG. 4 that has been performed so far, and starts the process shown in the flowchart of FIG.

In step S <b> 801, the CPU 201 calculates a print operation time t _p ′ from the current time t _s ′ until all the print jobs are completed (time t _pf ′) from the contents of the print job. As shown in FIG. 7 (i), the print operation time is the time from the time t _s 'to the time t _pf ' at which all print jobs are completed (t _pf '-t _s '). In step S802, the CPU 201 obtains the element temperature T _s ′ at the time t _s ′ when the print job is received (point P1 in FIG. 7A). S803 in CPU201, the time _{t s} of receiving a print job 'element temperature at _{T s',} the print operation time _{t p} calculated in S801', the printing speed V by referring to the table as an index, suitable drive time _{t f1} Select “and stop time t _f2 ”.

  Here, when the print speed V of the first print job is different from that of the next print job, the print speed V with the higher temperature rise rate of the element is adopted as an index. By controlling the fan 140 using the control parameters thus selected, the upper limit of the recommended operating temperature of the element is not exceeded. When a plurality of print jobs are received, the print speed V of the print job having the highest element temperature increase rate is selected. Furthermore, the magnitude of the temperature rise rate of the element for each print speed V is experimentally obtained in advance and stored in the ROM 202. The CPU 201 selects the print speed V based on the temperature increase rate of the element for each print speed V stored in the ROM 202.

In step S804, the CPU 201 determines whether the drive time t _f1 ′ and the stop time t _f2 ′ of all target elements have been determined. If the CPU 201 determines in step S804 that the drive time _tf1 ′ and the stop time _tf2 ′ have not been determined for all target elements, the process returns to step S802. If the CPU 201 determines that the drive time t _f1 ′ and the stop time t _f2 ′ of all the target elements have been determined in S804, the process proceeds to S805.

In step S805, the CPU 201 selects a control parameter as follows in order to prevent the temperature of all target elements from exceeding the temperature _Tmax , which is a threshold value for shifting to the temperature rise suppression mode. In other words, the CPU 201 selects the drive time t _f1 ′ and the stop time t _f2 ′ in which the drive time of the fan 140 is the longest among the drive times t _f1 ′ and stop time t _f2 ′ of each target element determined in S803. To do.

In step S806, the CPU 201 starts measuring the elapsed time from the time t _s ′ using a timer. In step S <b> 807, the CPU 201 stops the fan 140. Since the fan 140 may be started depending on the first print job, the process of S807 is performed. In step S808, the CPU 201 refers to the timer and determines whether or not the driving time _tf1 ′ has come. If the CPU 201 determines in S808 that the drive time _tf1 ′ has not been reached, the process returns to S808, and if it is determined that the drive time _tf1 ′ has been reached, the process proceeds to S809. In step S <b> 809, the CPU 201 drives the fan 140.

In S810, the CPU 201 refers to the timer and determines whether or not the stop time _tf2 ′ has come. S810 in the CPU201 is, 'If it is determined that not a, returns the process to S810, stop time _{t f2'} stop time _{t f2} when it is determined that it is a, the process proceeds to S811. In step S811, the CPU 201 stops the fan 140.

  Compared with the case where the control parameters of the fan 140 are determined only at the start of the printing operation (see the broken line graph in FIG. 7 (i)), the drive control (solid line) of the fan 140 of Example 2 enters the temperature increase suppression mode. The printing operation can be completed without any loss of productivity. Further, it is possible to suppress power consumption corresponding to the operation of the fan 140 being stopped during the printing operation.

  As described above, according to the second embodiment, it is possible to reduce the power consumption by the cooling means while not reducing the productivity.

  In the first embodiment, the element temperature T at the end of printing is estimated at the print start timing, and the control parameter of the fan 140 is determined. In the second embodiment, the control parameter of the fan 140 is determined at the start of printing, and when another job is entered during the printing operation, the element temperature T at the end of all printing is estimated again at that time, and the control parameter is determined again. Was. In the third embodiment, the element temperature T at that time is acquired every control cycle, the element temperature T at the end of printing is estimated every time, and the control parameter of the fan 140 is continuously corrected (determined). explain.

[Fan drive control]
When the controller unit 300 transmits job information and a print instruction to the image formation control unit 200 based on information from an apparatus such as an image reading apparatus or a computer, the CPU 201 starts the process of the flowchart of FIG. In step S901, the CPU 201 selects an element whose temperature rises severely, that is, an element that reaches the upper limit of the recommended operating temperature earliest. With reference to FIG. 9B, the element selection process in S901 with a severe temperature rise will be described. S911 in CPU201, as in Example 1, from the contents of the print job, calculates the printing operation time _{t p.} In step S912, the CPU 201 obtains the element temperature T _s when starting the printing operation. S913 in CPU201, the print operation time _{t p} calculated in element temperature _T s, S911 at the time of printing start, by referring to the table printing speed V as an index to determine the appropriate driving time _{t f1} and stop time _{t f2.}

S914 in CPU201 determines whether to determine the driving time _{t f1} and stop time _{t f2} of all subjects elements. If the CPU 201 determines in S914 that the drive time _tf1 and the stop time _tf2 have not been determined for all target elements, the process returns to S912. S914 in CPU201, when it is determined that determines the driving time _{t f1} and stop time _{t f2} of all target devices, the process proceeds to S915. S915 in CPU201, among the drive time _{t f1} and stop time _{t f2} of each target device determined in S913, and selects the element driving time is longest fan 140, the processing in the processing shown in FIG. 9 (a) return. The element thus selected is hereinafter referred to as a selected element.

Returning to the description of the flowchart of FIG. In step S902, the CPU 201 starts a printing operation. In step S <b> 903, the CPU 201 starts measurement of elapsed time for measuring timing for switching the operation of the fan 140 using a timer. In step S904, the CPU 201 stops driving the fan 140 until the driving time _tf1 ′ is reached. With reference to FIG. 9C, the stop process up to the drive time t _f1 ′ in S904 will be described.

In S941, the CPU 201 acquires the element temperature Ts ′ of the selected element at the current time. Thus, when the element temperature Ts ′ is acquired at a predetermined time, the selected element selected in the process of FIG. 9B is targeted. In step S <b> 942, the CPU 201 calculates a printing operation time t _p ′ from the current time until all the print jobs are completed from the contents of the print job. S943 in CPU201, the element temperature _{T s} of the selected element ', the print operation time _{t p',} referring to the table printing speed V as an index to determine the appropriate driving time _{t f1} '. Here, _'but it can also be determined, at the moment the drive time t _f1' by referring to the table stop time t _f2 are determined only driving time t _{f1 'so} only required.

In S944, the CPU 201 refers to the timer to determine whether or not the current time is the driving time _tf1 ′. If the CPU 201 determines in S944 that the drive time _tf1 'has not been reached, the CPU 140 stops the fan 140 in S945 and returns the process to S941. While the processing from S941 to S945 is repeated, the element temperature T _s ′ of the selected element changes. For this reason, the driving time t _f1 ′ determined in S943 is updated to a more appropriate value (also referred to as correction). If the CPU 201 determines in S944 that the drive time _tf1 'has come, the process returns to the process of FIG. The CPU 201 corrects the driving time t _f1 ′ while repeating the processing from S941 to S945. Therefore, the element temperature T is acquired in a cycle (also referred to as a control cycle) from S941 to S945, the element temperature T at the end of printing is estimated, and the drive time t _f1 ′, which is a control parameter, is corrected. It can be said.

Returning to the description of the flowchart of FIG. In step S905, the CPU 201 drives the fan 140 until the stop time _tf2 ′ is reached. With reference to FIG. 9D, the drive processing up to the stop time t _f2 ′ in S905 will be described. In S951, the CPU 201 acquires the element temperature T _s ′ of the selected element at the current time. In step S <b> 952, the CPU 201 calculates a print operation time t _p ′ from the current time until the completion of all print jobs from the contents of the print job. S953 in CPU201, the element temperature _{T s} of the selected element ', the print operation time _{t p',} referring to the table printing speed V as an index to determine the appropriate stopping time _{t f2} '.

S954 in the CPU201 is, by referring to the timer, it is determined whether or not the current time has become to stop time _{t f2} '. S954 in CPU201, when it is determined that not in the stop time _{t f2} ', by driving the fan 140 at S955, the process returns to S951. At this time, as described above, the stop time t _f2 ′ is updated (corrected) in accordance with the change in the element temperature T _s ′ of the selected element. If the CPU 201 determines in S954 that the stop time t _f2 ′ has been reached, the process returns to the process of FIG. The CPU 201 corrects the stop time t _f2 ′ while repeating the processing from S951 to S955. From this, it can be said that the element temperature T is acquired in a cycle (control cycle) in which S951 to S955 are repeated, the element temperature T at the end of printing is estimated, and the stop time t _f2 ′, which is a control parameter, is corrected. . Returning to the description of the flowchart of FIG. In step S906, the CPU 201 stops the fan 140 and ends the process.

Thus, by increasing the number of times of obtaining the element temperature T and estimating the element temperature T at the end of printing, the control parameters (drive time t _f1 and stop time t _f2 ) are updated (corrected) to more optimal values. It will be done. Since the operation of the fan 140 can be controlled more optimally, power saving can be achieved. Moreover, since it can prevent that element temperature T shift | deviates from the estimated temperature and transfers to temperature rising suppression mode, the fall of productivity can also be reduced.

  As described above, according to the third embodiment, it is possible to reduce the power consumption by the cooling unit while not reducing the productivity.

109 Fixing / Emitting Sensor 120 Process Cartridge 140 Fan 201 CPU
400 Temperature sensor 500 Temperature sensor

Claims (9)

An image forming apparatus for forming an image on a recording material,
A member whose temperature rises with the printing operation;
Cooling means for cooling the member;
Detecting means for detecting the temperature of the member;
Control means for controlling the driving of the cooling means;
With
The control means determines whether the temperature of the member when the printing operation is completed is predetermined based on the temperature of the member detected by the detection means when the printing operation is started and the time required for the printing operation. An image forming apparatus, wherein a parameter for driving the cooling unit is determined so as not to exceed a temperature of the image forming apparatus.   The predetermined temperature is a temperature lower than a temperature used for determination to shift to a mode for performing a process of stopping the print operation or a process of reducing a throughput during the print operation. The image forming apparatus according to claim 1. A plurality of the members;
The control unit determines the parameter for each of the plurality of members, and selects and selects the parameter in which the cooling unit is driven for the longest time among the plurality of determined parameters. The image forming apparatus according to claim 1, wherein the driving of the cooling unit is controlled using the parameter.   4. The control unit according to claim 1, wherein the control unit obtains a time required for the printing operation based on a number of recording materials printed in the printing operation and a throughput of the printing operation. 2. The image forming apparatus according to item 1. A process cartridge including at least a photosensitive member on which an electrostatic latent image is formed, and developing means for developing the electrostatic latent image on the photosensitive member with toner to form a developer image;
Transfer means for transferring a developer image formed by the process cartridge to a recording material;
Fixing means for performing a fixing process on an unfixed developer image on the recording material transferred by the transfer means;
A recording material detecting means for detecting the recording material subjected to the fixing process by the fixing means;
With
The image forming apparatus according to claim 1, wherein the member includes the process cartridge or the recording material detection unit.   When the control means receives an instruction for the next print operation to be continuously executed while the print operation is being performed, the control means is detected by the detection means when the next print operation is received. 6. The image formation according to claim 1, wherein the parameter is determined again based on the temperature of the member, and the driving of the cooling unit is controlled using the parameter determined again. apparatus.   7. The control unit according to claim 1, wherein the control unit determines, as the parameter, a driving time for starting driving of the cooling unit and / or a stop time for stopping driving of the cooling unit. The image forming apparatus described in the item.   The image according to claim 7, wherein the control unit updates the stop time while the cooling unit is driven, and stops driving the cooling unit using the updated stop time. Forming equipment.   The image according to claim 7, wherein the control unit updates the driving time while the cooling unit is stopped, and starts driving the cooling unit using the updated driving time. Forming equipment.

Images