JP7057089B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus such as a copier, a printer, and a facsimile machine using an electrophotographic method or an electrostatic recording method, and more specifically, the temperature to be predicted in the image forming apparatus when the power is turned on. It relates to an image forming apparatus having a predicting function.

In an image forming apparatus using an electrophotographic method or the like, a toner image formed on an image carrier such as a photoconductor is transferred to a recording material directly or via an intermediate transfer body, and then the toner image is fixed to the recording material by means for fixing the toner image to the recording material. Is fixed by. As the fixing means, a fixing device, which is a heating device having a heating element for heating a recording material carrying an unfixed toner image, is widely used.

In such an image forming apparatus, the temperature at various points in the image forming apparatus (hereinafter referred to as "in-flight temperature") is affected by the heat of the fixing device, the transfer of the heated recording material, the heat generation of the electric element, and the like. Rise. An excessive rise in the cabin temperature may lead to image defects and the like. Therefore, there is an image forming apparatus that predicts the temperature of the prediction target in the image forming apparatus and controls the operation of the image forming apparatus so that the predicted temperature does not exceed a preset temperature. For example, a temperature rise suppressing operation such as making the image forming apparatus stand by for a certain period of time is executed. Further, there is an image forming apparatus that predicts the temperature to be predicted when the power is turned on again when the power supply is stopped due to a power failure or the like.

Patent Document 1 discloses a method of predicting the temperature of a prediction target when the power is turned on again based on the detection result of a fixing thermistor provided for detecting the temperature of the fixing device. That is, the elapsed time in the state where the power supply is stopped is estimated based on the detection results of the fixing thermistor when the power is turned off and when the power is turned on, and the estimated elapsed time and the prediction target stored in the storage unit immediately before the power is turned off. From the temperature, the temperature to be predicted when the power is turned on again is predicted.

Japanese Unexamined Patent Publication No. 2010-134407

However, the fixing thermistor is required to accurately detect the temperature of the fixing device in the fixing process. Therefore, as the fixing thermistor, one having high detection accuracy in a high temperature region and low detection accuracy in a low temperature region such as room temperature is generally used. Further, the temperature of the fixing device drops sharply after the fixing step is completed. For these reasons, if the elapsed time from the end of the fixing process is long when the power is turned on again, the estimation accuracy of the elapsed time in the state where the power supply is stopped is low. As a result, when predicting the temperature of a prediction target whose temperature drops more slowly than that of the fixing device, for example, the temperature of the process cartridge, the prediction accuracy of the temperature of the prediction target when the power is turned on again becomes low.

In order to deal with the above-mentioned decrease in accuracy, even if the temperature of the prediction target is sufficiently lowered when the power is turned on again, priority is given to suppressing defects such as image defects, and the temperature of the prediction target is actually set. It is possible to predict higher than the temperature. However, in this method, for example, when continuous printing is performed after the power is turned on again, the temperature rise suppressing operation is executed earlier than the time when it is actually necessary, which may reduce the image productivity.

Therefore, an object of the present invention is to accurately predict the temperature of the prediction target in the image forming apparatus when the power supply to the image forming apparatus is started, such as when the power supply is turned on again when the power supply is stopped due to a power failure or the like. It is to provide an image forming apparatus which can be done.

The above object is achieved by the image forming apparatus according to the present invention. In summary, the present invention is an image forming apparatus having an image forming means for forming a toner image on a recording material, and a fixing means for heating and fixing an unfixed toner image formed on the recording material on the recording material. A fixing thermista that detects the temperature of the fixing means, a cooling fan that introduces outside air into the image forming apparatus, an environmental temperature detecting means arranged in the vicinity of the leeward of the cooling fan in the image forming apparatus, and the above. An in-flight temperature detecting means that is arranged downstream in the ventilation direction from the environmental temperature detecting means in the image forming apparatus and detects the in-flight temperature, and a predicting means that predicts the target temperature that is the temperature of the prediction target in the image forming apparatus. In the state where the power is supplied to the image forming apparatus, the information indicating the target temperature is provided based on the information regarding the temperature fluctuation of the prediction target set in advance according to the operating state of the image forming apparatus. The predictive means has a predictive means to be acquired, a storage means for storing the information indicating the temperature inside the machine and the information indicating the target temperature, and holding the information even when the power supply to the image forming apparatus is stopped. Is information indicating the temperature of the fixing means detected by the fixing thermistor when the power supply to the image forming apparatus is started from the state where the power supply to the image forming apparatus is stopped. The information indicating the environmental temperature detected by the environmental temperature detecting means at the start, the information indicating the in-flight temperature detected at the start, and the information indicating the in-flight temperature detected at the start are stored in the storage means before the stop. Based on the information indicating the in-machine temperature and the information indicating the target temperature, the information indicating the target temperature at the start is acquired , and is detected by the fixing thermista at the start. When the fixing device temperature rise amount Tfe, which is the difference between the temperature of the fixing means and the environmental temperature detected by the environmental temperature detecting means at the start, is larger than the predetermined temperature, the fixing device temperature rise amount Tfe When the information indicating the target temperature at the start is acquired based on the parameter according to the value and the temperature rise amount Tfe of the fixing device is smaller than the predetermined temperature, the in-flight temperature detected at the start and the above. At the time of the start, the information indicating the target temperature at the time of the start is acquired based on the parameter corresponding to the value of the in-flight atmosphere temperature rise rate Tsx based on the difference in the environmental temperature detected by the environmental temperature detecting means. It is an image forming apparatus characterized by this.

According to the present invention, it is possible to accurately predict the temperature of the prediction target in the image forming apparatus when the power supply to the image forming apparatus is started, such as when the power supply is turned on again when the power supply is stopped due to a power failure or the like. Can be done.

It is a schematic cross-sectional view of an image forming apparatus. It is a block diagram which shows the control mode of the main part of an image forming apparatus. It is a graph for demonstrating the acquisition method of the temperature rise prediction parameter of a normal operation prediction unit. It is a flowchart of the temperature prediction process of the normal operation prediction unit. It is a graph which shows the temperature drop curve of the developing container temperature T, the fixing temperature Tf, and the machine atmosphere temperature Ts. It is a graph for demonstrating the acquisition method of the temperature rise prediction parameter of the low power consumption mode return prediction unit, and the table which shows the parameter. It is a graph for explaining the acquisition method of the temperature rise prediction parameter of the power-on time prediction unit, and the table which shows the parameter. It is a graph for explaining the acquisition method of the temperature rise prediction parameter of the power-on time prediction unit, and the table which shows the parameter. It is a flowchart of the temperature prediction process of the prediction unit at the time of returning to a low power consumption mode. It is a flowchart of the temperature prediction process of the power-on time prediction unit. It is a flowchart of the temperature rise suppression process of a temperature rise suppression part. It is a graph for demonstrating the effect of an Example.

Hereinafter, the image forming apparatus according to the present invention will be described in more detail with reference to the drawings.

[Example 1]
1. 1. Overall Configuration and Operation of the Image Forming Device FIG. 1 is a schematic cross-sectional view of the image forming apparatus 100 of the present embodiment. The image forming apparatus 100 of this embodiment is a laser beam printer using an electrophotographic method.

The image forming apparatus 100 has a recording material cassette 110 that can be attached to and detached from the apparatus main body (hereinafter, simply referred to as “device main body”) 101 of the image forming apparatus 100. The recording material cassette 110 can accommodate a plurality of recording materials (sheets, transfer materials) S such as recording paper. When the print start signal is emitted by the control unit 300 described later that controls the operation of the image forming apparatus 100, the feeding roller 111 is rotationally driven. By the rotation of the feeding roller 111, one sheet is fed from the uppermost recording material S among the recording materials S loaded on the recording material cassette 110, and the downstream side of the feeding roller 111 in the transport direction of the recording material S. It is conveyed toward the transfer roller pair 109 arranged in. The recording material S is conveyed further toward the downstream side by the transfer roller pair 109.

Further, the process cartridge 200 is detachably attached to the apparatus main body 101. The process cartridge 200 includes a photosensitive drum 201 as an image carrier, a charging roller 202 as a charging means, a developing device 203 as a developing means, a cleaning device 204 as a cleaning means, and the like. The photosensitive drum 1 is a drum-shaped (cylindrical) electrophotographic photosensitive member (photoreceptor). The charging roller 2 is a roller-type charging member arranged in contact with the photosensitive drum 1. The developing apparatus 203 includes a developing container 231 as an accommodating container for accommodating a developing agent, a developing roller 232 as a developing agent carrier, and the like. The cleaning device 204 includes a cleaning container 241 as a developer recovery container, a cleaning blade 242 as a cleaning member arranged in contact with the photosensitive drum 201, and the like.

An image (toner image) of the developer is formed on the photosensitive drum 201 at the same timing as the transfer of the recording material S by the transfer roller pair 109. That is, the surface of the photosensitive drum 201 is uniformly charged to a predetermined potential having a predetermined polarity (negative electrode property in this embodiment) by the charging roller 202. The surface of the charged photosensitive drum 201 is irradiated with laser light modulated based on image data from an exposure device (laser scanner) 108 as an exposure means arranged at the upper part in the drawing of the process cartridge 200. As a result, an electrostatic latent image (electrostatic image) is formed on the surface of the photosensitive drum 201. The electrostatic image formed on the surface of the photosensitive drum 201 is developed (realized) by the developing apparatus 203 using a developer (toner). The developing device 203 develops an electrostatic latent image by supplying the developing agent contained in the developing container 231 to the photosensitive drum 201 by the developing roller 232.

The image formed on the surface of the photosensitive drum 201 is transferred to the recording material S which is narrowly held and conveyed by the transfer roller 206 as the transfer means and the photosensitive drum 201. The transfer roller 206 is a roller-type transfer member, and is urged toward the surface of the photosensitive drum 201 to form a transfer portion N at a contact portion between the photosensitive drum 201 and the transfer roller 206. Further, the developer that is not transferred to the recording material S and remains on the surface of the photosensitive drum 201 is removed from the surface of the photosensitive drum 201 by the cleaning device 204 and recovered, and the surface of the photosensitive drum 201 is cleaned. The cleaning device 204 scrapes the developer from the surface of the rotating photosensitive drum 201 by the cleaning blade 242 and stores the developer in the cleaning container 241.

The recording material S on which the image is transferred is conveyed toward the fixing device 103 arranged on the downstream side of the transfer unit N in the conveying direction of the recording material S. The fixing device 103 is an example of a heating device that heats the recording material S on which an image is formed. The fixing device 103 includes a fixing film 131 as a heating means, a heater 132 as a heating element, a pressure roller 133 as a pressure means, a fixing thermistor 134 arranged in the vicinity of the heater 132, and the like. The recording material S is heated and pressurized by the heater 134 and the pressure roller 133 while being sandwiched and conveyed between the fixing film 131 and the pressure roller 133. As a result, the image transferred to the recording material S is fixed (melted and fixed) to the recording material S. The detection result of the fixing thermistor 134 as a fixing temperature detecting means for detecting the fixing temperature Tf, which is the temperature of the fixing device 103, is used for controlling the heater 132 (fixing temperature), and the temperature to be predicted will be described in detail later. Used for prediction of.

The recording material S on which the image is fixed is conveyed toward the discharge roller pair 106 arranged on the downstream side of the fixing device 103 in the transport direction of the recording material S, and is transported to the outside of the device main body 101 (outside the machine) by the discharge roller pair 106. ). The recording material S discharged to the outside of the machine is loaded on the discharge tray 105.

Further, in the double-sided print mode, the discharge roller pair 106 is started to reverse at a predetermined timing before the recording material S is discharged to the outside of the machine. As a result, the recording material S is conveyed toward the double-sided transfer path 112, and then is conveyed toward the transfer roller pair 109 by the refeed roller pair 107. After that, the recording material S is discharged to the outside of the machine by the discharge roller pair 106 after the image is transferred by the transfer unit N and the image is fixed by the fixing device 103, as in the case of printing on the first surface.

In this embodiment, an image forming means for forming an image on the recording material S is configured by a process cartridge 200, an exposure apparatus 108, a transfer roller 206, and the like.

2. 2. When the image forming apparatus 100 performs the printing operation, the temperature inside the machine temperature, for example, the temperature inside the machine, for example, due to the heat generation of the heater 132 of the fixing device 103, the heat generation of the electric element, the heat transfer of the heated recording material S during transportation, and the like. The temperature of the process cartridge 200 rises.

The image forming apparatus 100 has a cooling fan 115 in order to suppress an increase in the temperature inside the machine. The cooling fan 115 is arranged near the inside of the opening 116a provided in the housing 116 of the apparatus main body 101, takes in outside air through the opening 116a, and is directed toward the process cartridge 200 by a duct (not shown). Blow outside air.

Then, in the vicinity of the leeward of the cooling fan 115, an environmental thermistor 113 as an environmental temperature detecting means for detecting an environmental temperature which is the temperature of the environment in which the image forming apparatus 100 is installed (environment around the image forming apparatus 100) is provided. Have been placed. The environmental thermistor 113 is mounted on the electric board 117.

Further, an in-flight atmosphere thermistor 114 as an in-flight temperature detecting means for detecting the in-flight temperature at a predetermined position in the image forming apparatus 100 is arranged on the downstream side of the environmental thermistor 113 in the blowing direction of the cooling fan 115. The in-flight atmosphere thermistor 114 is mounted on the electric board 117, and detects the in-flight atmosphere temperature Ts, which is the in-flight temperature in the vicinity of the mounting portion.

When the in-flight temperature at a predetermined position of the image forming apparatus 100, for example, the temperature of the process cartridge 200 is rising, the in-flight atmosphere temperature Ts detected by the in-flight atmosphere thermistor 114 also rises. Further, in such a situation, a detection error may occur between the environment detection temperature Te, which is the temperature detected by the environment thermistor 113, and the actual environment temperature Tet. The image forming apparatus 100 of this embodiment is configured such that a part of the cooling air of the cooling fan 115 is blown toward the environmental thermistor 113, and this detection error becomes small when the cooling fan 115 is driven. There is.

Here, the definitions of the main parameters related to the temperature used in the description of this embodiment are as follows.
Fixing temperature (heating temperature) Tf: Temperature of the fixing device detected by the fixing thermistor In-flight atmosphere temperature (in-flight temperature) Ts: In-flight temperature environment detected by the in-flight atmosphere thermistor Te: Environmental temperature environment detected by the environmental thermista Temperature Tet: Actual environmental temperature Development container temperature (target temperature) T: Predicted value of predicted target temperature (T = Tz + Te)
Measured temperature Tt: Measured value of predicted temperature at the time of acquisition of temperature rise suppression parameter Predicted temperature rise Tz: Predicted value of difference between predicted target temperature and environment detection temperature Predicted temperature rise Tmz: Stored in NVRAM Predicted temperature rise fluctuation temperature ΔTz: Predicted value of the temperature fluctuation amount of the prediction target in the prediction cycle during normal operation Memory atmosphere temperature rise amount Tmse: Difference between the in-flight atmosphere temperature and the environment detection temperature stored in NVRAM (Tmse) = Ts-Te)

3. 3. Control mode FIG. 2A is a block diagram showing a control configuration of the image forming apparatus 100. The apparatus main body 101 is provided with a control unit 300 as a control means for comprehensively controlling the operation of each unit of the image forming apparatus 100. The control unit 300 includes a CPU 301 as an arithmetic control means, a ROM 302 as a storage means, a RAM 304, an NVRAM 303, and the like. The CPU 301 performs various arithmetic processes necessary for controlling the image forming apparatus 100. The ROM 302 is a storage means for storing fixed information, and stores information such as programs, parameters, and tables necessary for the calculation of the CPU 301. The RAM 304 is a memory for temporarily storing information necessary for the CPU 301 to perform arithmetic processing. The NVRAM 303 is a non-volatile memory in which information does not volatilize even when the power supply to the image forming apparatus 100 is stopped, such as during a power failure.

FIG. 2B is a functional block diagram showing each means realized by the CPU 301 executing the program stored in the ROM 302 in the control unit 300.

The process cartridge 200 has a large amount of temperature rise, especially when a large number of continuous prints are performed in the double-sided print mode. At this time, if the temperature of the developing container 231 rises excessively, the developing agent contained in the developing container 231 exceeds the glass dislocation point and melts, and adheres to the seal member or the like in the process cartridge 200. There is a possibility that it will end up. As a result, image defects and toner leakage may occur.

Therefore, the image forming apparatus 100 of the present embodiment is configured to predict the temperature of the process cartridge 200, particularly the developing container 231 as a prediction target, and control the operation so that the predicted temperature does not exceed a preset temperature. ing.

The control unit 300 includes a process cartridge 200 as a prediction target, a prediction unit 311 as a prediction means for predicting the temperature T of the developing container, which is the temperature of the development container 231 in particular, and a temperature rise suppression unit 312 as a temperature rise suppression means. Has. The temperature rise suppressing unit 312 controls the operation of the image forming apparatus 100 so that the developing container temperature T does not exceed the threshold temperature Tmax which is a predetermined threshold set in advance. The temperature rise suppressing unit 312 will be described later.

The prediction unit 311 includes a normal operation prediction unit 311a as a normal operation prediction means, a low power consumption mode return prediction unit 311b as a low power consumption mode return prediction means, and a power-on prediction means as a power-on prediction means. It has a time prediction unit 311c.

The normal operation time prediction unit (hereinafter, also referred to as “first prediction unit”) 311a predicts the developing container temperature T at each time interval Δt during the normal operation of the image forming apparatus 100. During normal operation, power is supplied to the image forming apparatus 100, the power switch is turned on, and normal operation is possible, that is, a state in which printing operation or adjustment operation is performed, or printing operation. It refers to the state of waiting for adjustment operation.

The low power consumption mode return prediction unit (hereinafter, also referred to as “second prediction unit”) 311b predicts the developing container temperature T when the image forming apparatus 100 returns from the low power consumption mode to the normal operation. The low power consumption mode means a state in which power is supplied to the image forming apparatus 100, but the power switch is turned off (including a sleep state that is automatically started). In the low power consumption mode, the power supply target is limited to the control unit 300 or a part of the control unit 300, and the power consumption is suppressed to be lower than that in the normal operation.

The power-on prediction unit (hereinafter, also referred to as “third prediction unit”) 311c develops when the power is turned on to the image forming apparatus 100, for example, when recovering from a power failure or when the inlet cable is inserted into an outlet. Predict the container temperature T.

Further, the predictor 311 uses the temperature rise suppression parameter 313 as a fixed parameter when calculating the developing container temperature T. The temperature rise suppression parameter 313 generally attaches a thermocouple to the developing container 231 and monitors the fluctuation of the measured temperature Tt, which is the measured value of the temperature of the developing container 231, during various operations and stops of the image forming apparatus 100. By doing so, it is obtained experimentally. Further, the acquired temperature rise suppression parameter 311 is stored in the ROM 302 in advance.

In the present embodiment, the temperature prediction target is the process cartridge 200, particularly the developing container 231. However, the present invention is not limited to this, and other elements in the image forming apparatus 100 may be predicted. good. However, since it tends to be difficult to arrange the temperature detecting means in the unit that can be attached to and detached from the device main body 101 or in the device main body 101 in the vicinity of the unit from the viewpoint of space and cost, in this embodiment, the unit is set to the temperature. It can be said that it is particularly effective when it is a prediction target.

4. Temperature prediction processing 4-1. Normal operation prediction unit First, the temperature prediction process by the normal operation prediction unit (first prediction unit) 311a will be described.

The first prediction unit 311a uses the reached temperature rise amount Ta and the fluctuating temperature coefficient (temperature change coefficient) k as the temperature rise suppression parameter 313 when calculating the developing container temperature T. With reference to FIG. 3, a method of acquiring the reached temperature rise amount Ta and the fluctuating temperature coefficient k will be described.

In FIG. 3, the solid line g is time-series data of the measured temperature Tt of the developing container 231. The measurement conditions are as follows. The recording material S was loaded into the recording material cassette 110, and continuous printing was performed in the double-sided printing mode. The environmental temperature Tet in which the image forming apparatus 100 is installed was maintained at a constant temperature during the measurement. Further, continuous printing was started in a state where the initial temperature T0 of the measured temperature Tt of the developing container 231 and other in-machine temperatures substantially match the environmental temperature Tet (hereinafter, also referred to as “cold state”).

Of the temperature rise suppression parameters 313, the reached temperature rise amount Ta is acquired by using the following formula A. Here, T1 is the ultimate temperature, which is the temperature at which the actually measured temperature Tt of the developing container 231 converges by continuing the printing operation.
Ta = T1-T0 (Equation A)

Further, in FIG. 3, the broken line h is an approximate curve of the solid line g, and was obtained by using an exponential function represented by the following equation B. Here, k is a temperature coefficient of fluctuation and t is time. The fluctuating temperature coefficient k is obtained by selecting a value at which the broken line h fits the solid line g.
T = T1- (T1-T0) x e- ^kt (Equation B)

The temperature fluctuation of the developing container 231 differs depending on the operating state of the image forming apparatus 100. Therefore, the reached temperature rise amount Ta and the fluctuating temperature coefficient k are acquired for each of the various operating states of the image forming apparatus 100 during normal operation such as the double-sided print mode, the single-sided print mode, and the standby mode, and are stored in the ROM 302 in advance. Further, although the case where the temperature of the developing container 231 rises has been described as an example, when the initial temperature T0 of the developing container 231 is higher than the reached temperature T1, the temperature falls. Also in this case, the fluctuating temperature coefficient k is obtained by fitting the measured temperature Tt of the developing container 231 with the approximate curve of the formula B. Normally, the fluctuation temperature coefficient k at the time of temperature rise and the fluctuation temperature coefficient k at the time of temperature fall are different values, and are stored in the ROM 302 in advance as the temperature change coefficient kup at the time of rise and the temperature change coefficient kwon at the time of fall, respectively.

Next, the temperature prediction process by the first prediction unit 311a will be described with reference to the flowchart shown in FIG.

In S101, the first prediction unit 311a reads the predicted temperature rise amount Tz predicted so far from the RAM 304. Further, the first prediction unit 311a reads out the storage prediction temperature rise amount Tmz stored in the NVRAM 303.

In S102, the first prediction unit 311a reads out the reached temperature rise amount Ta and the temperature coefficient k of fluctuation corresponding to the operating state of the image forming apparatus 100 from the ROM 302.

In S103, the first prediction unit 311a acquires the detection result of the environment detection temperature Te by the environment thermistor 113 and the detection result of the in-flight atmosphere temperature Ts by the in-flight atmosphere thermistor 114.

In S104, the first prediction unit 311a calculates the fluctuation temperature ΔTz, which is the fluctuation amount of the predicted temperature rise amount Tz at the time interval Δt, using the following equation C.
ΔTz = k × Δt × (Ta−Tz) (Equation C)

In S105, the first prediction unit 311a calculates the predicted temperature rise amount Tz using the following formula D, updates it to the RAM 304, and stores it. Further, the first prediction unit 311a calculates the developing container temperature T using the following formula E, updates it to the RAM 304, and stores it.
Tz = Tz + ΔTz (Equation D)
T = Tz + Te (Equation E)

In S106, the first prediction unit 311a determines whether or not the relationship between the predicted temperature rise amount Tz and the memory predicted temperature rise amount Tmz satisfies the following condition A.
-1 (° C) <Tz-Tmz <1 (° C) (Condition A)

When the first prediction unit 311a determines in S106 that the condition A is satisfied, the first prediction unit 311a ends the temperature prediction process. On the other hand, when the first prediction unit 311a determines in S106 that the condition A is not satisfied, the process proceeds to S107, and the memory prediction temperature rise amount Tmz and the memory atmosphere temperature rise amount Tmse stored in the NVRAM 303 are updated. Later, the temperature prediction process is terminated. At this time, the first prediction unit 311a updates (overwrites) the stored predicted temperature rise amount Tmz stored in the NVRAM 303 with the predicted temperature rise amount Tz acquired this time. Further, the first prediction unit 311a obtains a new storage atmosphere temperature rise amount Tmse stored in the NVRAM 303 by the following equation, Tmse = Ts-Te, from the environment detection temperature Te and the in-flight atmosphere temperature Ts acquired this time. Update (overwrite) with the value.

The first prediction unit 311a executes the processing of the flowchart shown in FIG. 4 at each time interval Δt. That is, the predicted temperature rise amount Tz and the developing container temperature T stored in the RAM 304 are updated every time interval Δt. In this embodiment, this time interval Δt is set to 6 seconds.

Further, in this embodiment, the memory predicted temperature rise amount Tmz and the storage atmosphere temperature rise amount Tmse stored in the NVRAM 303 are updated when the condition A is met, but they may be updated every predetermined time interval Δt2. ..

4-2. Low power consumption mode return prediction unit and power-on time prediction unit Next, temperature prediction processing by the low power consumption mode return time prediction unit (second prediction unit) 311b and power-on power-on prediction unit (third prediction unit) 311c. explain.

<Development vessel temperature, in-machine atmosphere temperature temperature rise rate, fixing temperature temperature rise amount>
FIG. 5 shows a downward curve of the temperature of the developing container 231, the temperature of the fixing device 103, and the in-machine atmosphere temperature. In FIG. 5, the solid line a is time-series data of the measured temperature Tt of the developing container 231, and the thermocouple was attached to the developing container 231 for measurement. Further, the solid line b is the fixing temperature Tf, and the fixing thermistor 134 was driven by an external power source for measurement. Further, the solid line c is the in-flight atmosphere temperature Ts, and the in-flight atmosphere thermistor 114 was driven by an external power source for measurement. Further, the solid line d is the environmental temperature Tet of the image forming apparatus 100, and the environmental temperature Tet is kept constant. The measurement conditions are as follows. Continuous printing is performed in the double-sided print mode, and after the measured temperature Tt of the developing container 231 converges to the temperature (reached temperature) T2 and the in-machine atmosphere temperature Ts converges to the temperature (reached temperature) T3, the power switch of the image forming apparatus 100 is turned off. I made it. The timing of turning off the power switch was set to 0 minutes.

Here, for convenience, the temperature rise rate Tx of the developing container 231, the in-machine atmosphere temperature rise rate Tsx, and the fixing device temperature rise amount Tfe are defined by the following formula F, the following formula G, and the following formula H, respectively.
Tx = (Tt-Tet) / (T2-Tet) (Equation F)
Tsx = (Ts-Tet) / (T3-Tet) (Equation G)
Tfe = Tf-Tet (Equation H)

<Fire temperature prediction parameter of the second prediction unit>
With reference to FIG. 6, a method of acquiring the parameters m and n as the temperature rise prediction parameter 313 used by the second prediction unit 311b when calculating the developing container temperature T will be described.

FIG. 6A is a graph plotted by converting the vertical axis into a temperature rise rate Tx using the temperature measurement data shown in FIG. In FIG. 6A, the solid line e is the temperature rise rate Tx of the developing container 231. Further, the broken line f is an approximate straight line of the solid line e, and was obtained by using a linear function represented by the following equation I.
Ty = m × t1 + n (Equation I)

Here, Ty is an approximate temperature rise rate, m and n are temperature rise suppression parameters 313, and t1 is an elapsed time. The elapsed time t1 is divided into a plurality of regions, and the parameters m and n are acquired by fitting the solid line e with the approximate straight line represented by the equation I in each region. The parameters m and n take different values depending on the value of the elapsed time t1. The temperature rise suppression parameters m and n thus acquired are stored in the ROM 302 in advance in the form of the table A shown in FIG. 6 (b).

The method of dividing the elapsed time t1 and the values of the parameters m and n are examples, and it is possible to arbitrarily divide the elapsed time and acquire the parameters m and n. Further, in this embodiment, the parameters m and n are acquired so that the plurality of approximate straight lines indicated by the broken line f become continuous values according to the value of the elapsed time t1, but even if they are acquired so as to be discontinuous. good. For example, the elapsed time t1 may be divided into a plurality of regions, m = 0, and the parameter n may be acquired.

<Fire temperature prediction parameter of the 3rd prediction unit>
Next, with reference to FIGS. 7 and 8, a method for acquiring parameters p and q as the temperature rise prediction parameter 313 used when the third prediction unit 311c calculates the developing container temperature T will be described.

FIG. 7A is a graph plotted by converting the temperature measurement data shown in FIG. 5 into a fixing device temperature rise amount Tfe on the horizontal axis and a temperature rise rate Tx on the vertical axis. In FIG. 7A, the solid line r is the temperature rise rate Tx of the developing container 231. The Tfe is divided into a plurality of regions in the region (high temperature region) where the temperature rise amount Tfe> 25 (° C.) of the fixing device, and the representative value of the temperature rise rate Tx in each region is acquired as the parameter p. The parameter p thus acquired is stored in the ROM 302 in advance in the form of the table B shown in FIG. 7 (b).

FIG. 8A is a graph plotted by converting the temperature measurement data shown in FIG. 5 into an in-flight atmosphere temperature rise rate Tsx on the horizontal axis and a temperature rise rate Tx on the vertical axis. In FIG. 8A, the solid line s is the temperature rise rate Tx of the developing container 231. The in-flight atmosphere temperature rise rate Tsx is divided into a plurality of regions, and the representative value of the temperature rise rate Tx in each region is acquired as the parameter q. The parameter q thus acquired is stored in the ROM 302 in advance in the form of the table C shown in FIG. 8 (b).

<Temperature prediction processing of the second prediction unit>
Next, the temperature prediction process by the second prediction unit 311b will be described with reference to the flowchart shown in FIG.

In S201, when the second prediction unit 311b receives the low power consumption mode entry signal, the process proceeds to S202.

In S202, the second prediction unit 311b reads out the predicted temperature rise amount Tz stored in the RAM 304, and updates (overwrites) the stored predicted temperature rise amount Tmz stored in the NVRAM 303 with the predicted temperature rise amount Tz. After that, the image forming apparatus 100 enters the low power consumption mode.

In S203, the second prediction unit 311b causes the CPU 301 functioning as a measuring means to measure the elapsed time t1 from entering the low power consumption mode, and sequentially stores the elapsed time t1 in the RAM 304 as a counter. Here, in the low power consumption mode, the clock frequency of the CPU 301 is lowered and the amount of arithmetic processing is reduced in order to suppress the power consumption. The second prediction unit 311b measures the elapsed time t1 by raising the counter at a timing that is a predetermined multiple of the clock frequency of the CPU 301.

In S204, when the image forming apparatus 100 returns from the low power consumption mode, the second prediction unit 311b receives a return signal from the low power consumption mode.

In S205, the second prediction unit 311b reads out the storage prediction temperature rise amount Tmz stored in the NVRAM 303 at the time of entering the low power consumption mode.

In S206, the second prediction unit 311 reads out the parameters m and n according to the value of the elapsed time t1 with reference to the table A (FIG. 6B) stored in the ROM 302.

In S207, the second prediction unit 311b acquires the detection result of the environment detection temperature Te by the environment thermistor 113.

In S208, the second prediction unit 311b calculates the predicted temperature rise amount Tz using the following equation (J). Further, the second prediction unit 311b calculates the developing container temperature T by using the above-mentioned formula E. Further, the second prediction unit 311b ends the temperature prediction process after storing the calculated predicted temperature rise amount Tz and the developing container temperature T in the RAM 304.
Tz = Tmz × (m × t1 + n) (Equation J)

<Temperature prediction processing of the third prediction unit>
Next, the temperature prediction process by the third prediction unit 311c will be described with reference to the flowchart shown in FIG.

When the power supply to the image forming apparatus 100 is started, in S301, the third prediction unit 311c reads out the storage prediction temperature rise amount Tmz and the memory temperature rise amount Tmse from the NVRAM 303.

In S302, the third prediction unit 311c acquires the detection results of the fixing temperature Tf, the environment detection temperature Te, and the in-flight atmosphere temperature Ts by the fixing thermistor 134, the environment thermistor 113, and the in-flight atmosphere thermistor 114, respectively.

In S303, the third prediction unit 311c calculates the fixing device temperature rise amount Tfe and the in-flight atmosphere temperature rise rate Tsx. At this time, the third prediction unit 311c calculates the temperature rise amount Tfe of the fixing device by the following equation, Tfe = Tf-Te. Further, the third prediction unit 311c calculates the in-flight atmosphere temperature rise rate Tsx by the following equation, Tsx = (Ts-Te) / Tmse.

In S304, the third prediction unit 311c determines whether or not the fixing device temperature rise amount Tfe meets the following condition B.
Tfe> 25 (° C) (Condition B)

If the third prediction unit 311c determines in S304 that the condition B is satisfied, the process proceeds to S305. In S305, the third prediction unit 311c reads out the parameter p corresponding to the value of the fixing device temperature rise amount Tfe with reference to the table B (FIG. 7B) stored in the ROM 302. In S306, the third prediction unit 311c calculates the predicted temperature rise amount Tz using the following formula K. Further, the third prediction unit 311c stores the calculated predicted temperature rise amount Tz in the RAM 304, and then proceeds to the process in S309.
Tz = Tmz × p (Equation K)

On the other hand, if the third prediction unit 311c determines in S304 that the condition B is not satisfied, the process proceeds to S307. In S307, the third prediction unit 311c reads out the parameter q corresponding to the value of the in-flight atmosphere temperature rise rate Tsx with reference to the table C (FIG. 8B) stored in the ROM 302. In S308, the third prediction unit 311c calculates the predicted temperature rise amount Tz using the following formula L. Further, the third prediction unit 311c stores the calculated predicted temperature rise amount Tz in the RAM 304, and then proceeds to the process in S309.
Tz = Tmz × q (Equation L)

In S309, the third prediction unit 311c calculates the developing container temperature T using the above-mentioned formula E. Further, the third prediction unit 311c ends the temperature prediction process after storing the calculated developing container temperature T in the RAM 304.

5. Temperature rise suppression process Next, the temperature rise suppression process by the temperature rise suppression unit 312 will be described with reference to the flowchart shown in FIG. The temperature rise suppressing unit 312 carries out the processing of the flowchart shown in FIG. 11 every time the developing container temperature T is updated.

First, in S401, the temperature rise suppressing unit 312 determines whether or not the print command is transmitted in the control unit 300. Then, when the temperature rise suppressing unit 312 determines that the print command has not been transmitted in S401, the process ends. Further, when the temperature rise suppressing unit 312 determines that the print command is transmitted in S401, the process proceeds to S402.

In S402, the temperature rise suppressing unit 312 determines whether or not the image forming apparatus 100 is in the temperature rise suppressing operation. Here, F is a temperature rise suppression flag, takes a value of 1 or 0, and is stored in the RAM 304. When the image forming apparatus 100 is in the temperature rise suppression operation, 1 is stored in the temperature rise suppression flag F, and 0 is stored in other cases. When the temperature rise suppression unit 312 determines in S402 that 0 is stored in the temperature rise suppression flag F, that is, when the image forming apparatus 100 is not in the temperature rise suppression mode, the process is set to S403. Proceed.

In S403, the temperature rise suppressing unit 312 determines whether or not the developing container temperature T read from the RAM 304 exceeds the threshold temperature Tmax read from the ROM 302 (whether it is equal to or lower than the threshold temperature Tmax). The threshold temperature Tmax is preset as a fixed parameter and stored in the ROM 302.

When the temperature rise suppressing unit 312 determines in S403 that the developing container temperature T is equal to or lower than the threshold temperature Tmax, the process proceeds to S405. Then, in S405, the temperature rise suppressing unit 312 permits the image forming operation. As a result, the image forming operation is executed. Further, when the temperature rise suppressing unit 312 determines in S403 that the developing container temperature T exceeds the threshold temperature Tmax, the process proceeds to S406. Then, in S406, the temperature rise suppression unit 312 stores 1 in the temperature rise suppression flag F. After that, in S408, the temperature rise suppressing unit 312 executes the temperature rise suppressing operation. In this embodiment, the temperature rise suppressing unit 312 controls the image forming apparatus 100 to be in the standby state as the temperature rise suppressing operation. The temperature rise suppressing operation is not limited to the operation of temporarily stopping the image forming operation, for example, the amount of air flowing into the device main body 101 per unit time by increasing the driving speed of the fan and the device main body 101. It may be an arbitrary operation such as an operation of increasing the amount of air discharged from the air.

Further, when the temperature rise suppression unit 312 determines in S402 that 1 is stored in the temperature rise suppression flag F, that is, when the image forming apparatus 100 is in the temperature rise suppression operation, the process is performed in S404. Proceed to. In S404, the temperature rise suppressing unit 312 determines whether or not the relationship between the developing container temperature T, the threshold temperature Tmax, and the cooling temperature R satisfies the following condition C. Here, R is a cooling temperature, which is preset as a fixed parameter and stored in the ROM 302. That is, it is determined whether or not the developing container temperature T has dropped by a predetermined temperature.
T> Tmax-R (Condition C)

If the temperature rise suppressing unit 312 determines in S404 that the condition C is satisfied, the process proceeds to S408. Then, in S408, the temperature rise suppressing unit 312 continues the temperature rise suppressing operation. If the temperature rise suppressing unit 312 determines in S404 that the condition C is not satisfied, the process proceeds to S407. Then, in S407, the temperature rise suppression unit 312 stores 0 in the temperature rise suppression flag F and ends the temperature rise suppression operation. Further, the processes of S402, S403, and S405 are subsequently performed, the image forming operation is permitted in S405, and the image forming operation is executed.

6. Effect Next, the effect of this embodiment will be described. In this embodiment, the power-on prediction unit (third prediction unit) 311c switches the temperature prediction process for calculating the developing container temperature T according to the value of the fixing device temperature rise amount Tfe at the time of power-on. That is, in the case of a high temperature region where the fixing device temperature rise amount Tfe meets the condition B, the third prediction unit 311c calculates the predicted temperature rise amount Tz using the fixing temperature Tf detected by the fixing thermistor 134. .. On the other hand, in the case of a low temperature region where the fixing device temperature rise amount Tfe does not meet the condition B, the third prediction unit 311c uses the in-flight atmosphere temperature Ts detected by the in-flight atmosphere thermistor 114 to determine the predicted temperature rise amount Tz. Calculate. That is, the detection result of the in-flight atmosphere thermistor 114, which has a relatively high detection accuracy in the low temperature region in the low temperature region near room temperature, is used, and the detection accuracy in the high temperature region is relatively high in the high temperature region near the fixing temperature. The developing vessel temperature T is predicted using the detection result of the thermistor 134. Thereby, for example, the developing vessel temperature T can be accurately predicted in both the low temperature region and the high temperature region without separately providing a highly accurate temperature detecting means in the low temperature region and the high temperature region. As a result, the developing container temperature T at the time of turning on the power can be accurately predicted regardless of the elapsed time from the stop of the power supply to the turning on of the power again.

With reference to FIG. 12, the results of examining the prediction accuracy of the temperature of the developing container 231 in the present embodiment and the comparative example will be described. Here, the measured temperature Tt of the developing container 231 and the developing container temperature T are compared with each other, taking as an example the case where the elapsed time from the power supply stop to the power re-turning on is long. In the comparative example, the third prediction unit 311c is configured to directly shift to S305 after the processing of S303 in the flowchart shown in FIG. Then, in the comparative example, in the table B shown in FIG. 7B, the value of the parameter p in the case of Tfe ≦ 25 (° C.) (low temperature region) was set to 0.5. Except for these points, the configuration and operation of the image forming apparatus 100 of the comparative example are substantially the same as those of the image forming apparatus 100 of the present embodiment.

The measurement conditions are as follows. When the developing container temperature T was the threshold temperature Tmax, the power supply to the image forming apparatus 100 was stopped. Then, it was left until the image forming apparatus 100 became a cold state. Then, after the power was turned on to the image forming apparatus 100, continuous printing in the double-sided printing mode was started. The timing of printing start was set to 0 minutes. In order to compare the temperature prediction accuracy of the developing container 231, the control program of the image forming apparatus 100 was changed so that the temperature rise suppressing unit 312 does not function in both the present embodiment and the comparative example.

In FIG. 12, the solid line u is the measured temperature Tt of the developing container 231, the broken line v is the developing container temperature T of this embodiment, and the broken line w is the developing container temperature T of the comparative example. As can be seen from FIG. 12, the initial temperature of the developing container temperature T of the comparative example is larger than the initial temperature of the measured temperature Tt. Therefore, the developing container temperature T of the comparative example reaches the threshold temperature Tmax at a timing earlier than the measured temperature Tt. As a result, in the comparative example, the temperature rise suppressing operation is started earlier than necessary. As a result, there is a concern that image productivity will decrease. On the other hand, the initial temperature of the developing container temperature T of this embodiment is almost the same as the initial temperature of the measured temperature Tt. Further, the developing container temperature T of this embodiment reaches the threshold temperature Tmax at a timing substantially coincide with the measured temperature Tt. Therefore, in this embodiment, the temperature rise suppressing operation is not performed earlier than necessary.

As described above, the image forming apparatus 100 of this embodiment has an in-flight atmosphere thermistor 114 as an in-flight temperature detecting means for detecting the in-flight temperature (in-flight atmosphere temperature). Further, the image forming apparatus 100 has a predicting unit 311 as a predicting means for predicting a target temperature (development container temperature in this embodiment) which is a prediction target temperature in the image forming apparatus. The prediction unit 311 determines the target temperature based on the information (FIG. 3) regarding the temperature fluctuation of the prediction target set in advance according to the operating state of the image forming apparatus 100 in the state where the power is supplied to the image forming apparatus 100. Get the information shown. Further, the image forming apparatus 100 has an NVRAM 303 as a storage means for storing information indicating the temperature inside the machine and information indicating the target temperature, and holding the information even when the power supply to the image forming apparatus 100 is stopped. Then, when the power supply to the image forming apparatus 100 is started from the state where the power supply to the image forming apparatus 100 is stopped, the prediction unit 311 gives information indicating the target temperature at the time of the start as follows. To get. That is, the target at the start is based on the information indicating the in-flight temperature detected at the start, the information indicating the in-flight temperature stored in the NVRAM 303 before the stop, and the information indicating the target temperature. Get information indicating the temperature. In particular, in this embodiment, the prediction unit 311 is the target at the start of the above based on the preset information (FIG. 8) indicating the relationship between the rate of change in the in-flight temperature and the rate of change in the target temperature. Get information indicating the temperature.

Further, in this embodiment, the image forming apparatus 100 has a fixing thermistor 134 as a heating temperature detecting means for detecting the fixing temperature as the heating temperature. Then, in the present embodiment, when the power supply to the image forming apparatus 100 is stopped from the state where the power supply to the image forming apparatus 100 is stopped, the prediction unit 311 is a condition in which the fixing temperature detected at the time of the start is preset. When the condition is satisfied, the information indicating the target temperature at the start is acquired as follows. That is, based on the information indicating the fixing temperature detected at the start and the information indicating the target temperature stored in the NVRAM 303 before the stop, the information indicating the target temperature at the start is acquired. do. In particular, in this embodiment, the prediction unit 311 is based on preset information (FIG. 7) indicating the relationship between the amount of change in the fixing temperature and the rate of change in the target temperature, and the target temperature at the start of the above. Get the information that indicates.

Further, in this embodiment, the image forming apparatus 100 can operate in a normal mode (during normal operation) and a low power consumption mode in a state where power is supplied. The normal mode is a mode in which the prediction unit 311 can acquire information indicating the target temperature at preset time intervals. The low power consumption mode is a mode in which the prediction unit 311 cannot acquire information indicating the target temperature at preset time intervals. Further, in the present embodiment, the image forming apparatus 100 has a measuring means for measuring the elapsed time in the low power consumption mode. In this embodiment, the CPU 301 functions as a measuring means. Then, when the prediction unit 311 returns to the normal mode after shifting from the normal mode to the low power consumption mode, the prediction unit 311 acquires information indicating the target temperature at the time of the return as follows. That is, based on the elapsed time measured after the transition, the information indicating the target temperature acquired immediately before the transition, and the information indicating the target temperature at the time of the return, the information indicating the target temperature is acquired. In particular, in this embodiment, the prediction unit 311 provides preset information indicating the relationship between the elapsed time from the transition from the normal mode to the low power consumption mode and the rate of change in the target temperature (FIG. 6). Based on this, information indicating the target temperature at the time of the return is acquired.

Here, in this embodiment, the image forming apparatus 100 has an environmental thermistor 113 as an environmental temperature detecting means for detecting an environmental temperature which is the temperature of the environment in which the image forming apparatus 100 is installed. In this embodiment, the information indicating the target temperature is information indicating the difference between the environmental temperature and the target temperature. Further, the information indicating the in-flight temperature is information indicating the difference between the environmental temperature and the in-flight temperature. Further, the information indicating the fixing temperature is information indicating the difference between the environmental temperature and the fixing temperature. Then, in this embodiment, the prediction unit 311 obtains the target temperature based on the information indicating the target temperature and the environmental temperature.

With such a configuration, according to the present embodiment, even when the power supply to the image forming apparatus 100 is stopped due to a power failure or the like, the temperature of the prediction target in the image forming apparatus 100 at the time of turning on the power again is accurately predicted. Can be done. Further, even when continuous printing is performed after the power is turned on again, it is possible to suppress the execution of the temperature rise suppressing operation earlier than the time when it is actually necessary.

[others]
Although the present invention has been described above with reference to specific examples, the present invention is not limited to the above-mentioned examples.

In the above-described embodiment, the image forming apparatus is a process cartridge detachable image forming apparatus, but the present invention is not limited thereto. For example, the developing device or the developing container may be a unit that can be attached to and detached from the main body of the device substantially by itself. In general, the process cartridge is a cartridge in which a photoconductor and at least one of a charging means, a developing means, or a cleaning means as a process means acting on the photoconductor are integrally formed into a cartridge and can be attached to and detached from the main body of the apparatus. It was supposed to be.

In the above-described embodiment, the case where the power supply to the image forming apparatus is stopped due to a power failure has been described as an example, but the case where the operator such as a user or a service person intentionally stops the power supply to the image forming apparatus. The same applies even if it is.

Further, in the above-described embodiment, the temperature rise suppressing unit as the control means suppresses the temperature rise of the predicted target when the target temperature predicted by the predicting means exceeds the preset temperature (lowers the temperature). The case where the operation is executed has been described as an example. However, the operation executed according to the prediction result of the temperature of the prediction target is not limited to this, and may be an operation of suppressing a decrease in the temperature of the prediction target (increasing the temperature). That is, the control means is provided with an operation of suppressing a decrease in the temperature of the predicted target (increasing the temperature) when the target temperature predicted by the predicting means is equal to or lower than a preset temperature, for example, a heater of a fixing device or a separate control means. The heating operation of the heater may be executed. Further, the process executed according to the prediction result of the temperature of the prediction target is not limited to the process of controlling the temperature of the prediction target, for example, the operation of stirring the developer in the developing container according to the prediction result. It may be an arbitrary process for controlling the presence / absence of execution and the execution time. That is, the control means may change the operating state of the image forming apparatus according to the target temperature predicted by the prediction means.

Further, the heating device for heating the recording material on which the image is formed is typically a fixing device for fixing the unfixed toner image to the recording material, but the recording material on which the toner image is fixed is reheated. It may be a device for controlling gloss.

100 Image forming device 103 Fixing device 113 Environmental thermistor 114 In-flight atmosphere thermistor 132 Heater 134 Fixing thermistor 200 Process cartridge 231 Development container 300 Control unit 303 NVRAM
311 Prediction unit 312 Temperature rise suppression unit 313 Temperature rise prediction parameter

Claims (7)

An image forming apparatus having an image forming means for forming a toner image on a recording material.
A fixing means for heating and fixing the unfixed toner image formed on the recording material to the recording material,
A fixing thermistor that detects the temperature of the fixing means,
A cooling fan that introduces outside air into the image forming apparatus,
An environmental temperature detecting means arranged in the vicinity of the leeward side of the cooling fan in the image forming apparatus, and
An in-flight temperature detecting means that is arranged downstream in the blowing direction from the environmental temperature detecting means in the image forming apparatus and detects the in-flight temperature, and an in-flight temperature detecting means.
It is a prediction means for predicting the target temperature, which is the temperature of the prediction target in the image forming apparatus, and is preset according to the operating state of the image forming apparatus in a state where the power is supplied to the image forming apparatus. A prediction means for acquiring information indicating the target temperature based on the information regarding the temperature fluctuation of the prediction target, and
A storage means for storing information indicating the temperature inside the machine and information indicating the target temperature, and holding the information even when the power supply to the image forming apparatus is stopped.
Have,
When the power supply to the image forming apparatus is started from the state where the power supply to the image forming apparatus is stopped, the predicting means is the temperature of the fixing means detected by the fixing thermistor at the time of the start. Information indicating the environment temperature detected by the environmental temperature detecting means at the start, information indicating the in-flight temperature detected at the start, and the storage means before the stop. Based on the information indicating the in-flight temperature and the information indicating the target temperature stored in the above, the information indicating the target temperature at the start is acquired.
The temperature rise amount Tfe of the fixing device, which is the difference between the temperature of the fixing means detected by the fixing thermistor at the start and the environmental temperature detected by the environmental temperature detecting means at the start, is larger than the predetermined temperature. In this case, information indicating the target temperature at the start is acquired based on the parameter corresponding to the value of the temperature rise amount Tfe of the fixing device.
When the temperature rise amount Tfe of the fixing device is smaller than the predetermined temperature, the in-flight atmosphere rises based on the difference between the in-flight temperature detected at the start and the environmental temperature detected by the environmental temperature detecting means at the start. Obtaining information indicating the target temperature at the start, based on a parameter corresponding to the value of the temperature factor Tsx.
An image forming apparatus characterized in that. The image forming apparatus has a normal mode in which information indicating the target temperature can be acquired by the predicting means at preset time intervals and a low power consumption mode in which the prediction means cannot be acquired while the power is supplied. It has a measuring means for measuring the elapsed time in the low power consumption mode.
When the normal mode is changed to the low power consumption mode and then the normal mode is returned to the normal mode, the predictive means measures the elapsed time measured after the transition and the target temperature acquired immediately before the transition. The image forming apparatus according to claim 1, wherein the information indicating the target temperature is acquired based on the information shown. The predictive means measures after the transition based on preset information indicating the relationship between the elapsed time from the transition from the normal mode to the low power consumption mode and the rate of change in the target temperature. The image formation according to claim 2, wherein the information indicating the target temperature at the time of the return is acquired from the elapsed time obtained and the information indicating the target temperature acquired immediately before the transition. Device. The image forming apparatus according to any one of claims 1 to 3, wherein the prediction target is a container containing toner for forming an image, or a unit including the container. The image forming apparatus according to claim 4, wherein the container or the unit is removable from the apparatus main body of the image forming apparatus. The image forming apparatus according to any one of claims 1 to 5, further comprising a control means for changing the operating state of the image forming apparatus according to the target temperature predicted by the predicting means. Any of claims 1 to 5, further comprising a control means for executing an operation of suppressing an increase in the temperature of the predicted target when the target temperature predicted by the predicting means exceeds a preset temperature. The image forming apparatus according to claim 1.

Images