JP3315495B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus using an electrophotographic process, and more particularly to temperature control of a fixing heater.

[0002]

2. Description of the Related Art FIG. 5 is a sectional view showing an example of an image forming apparatus using an electrophotographic process, for example, a laser beam printer.

[0005] In FIG. 5, reference numeral 100 denotes a controller, which converts an electric signal, which is code data input from a host computer (not shown), into a video controller 1.
03, the image is developed into a dot image and stored in the internal memory of the video controller unit 103.
To be transmitted as a video signal.

[0004] Each element of the engine unit 102 is controlled by an engine controller 105, and the controller unit 10
Transmission / reception of video signals to / from the engine controller 10
5 is performed. A video signal input to a video interface unit (not shown) of the engine controller 105 is sent to a laser driver 106, where ON / OFF of the semiconductor laser 107 is controlled.

The laser light 110 emitted from the semiconductor laser 107 is deflected by the polygon mirror 108 to become scanning light in the longitudinal direction of the photosensitive drum 112,
09 onto the photosensitive drum 112. The photosensitive drum 112 rotates in the direction of the arrow, and is primarily charged by the primary charger 111, and then receives an exposure corresponding to ON / OFF of the laser beam to form an electrostatic latent image on the surface of the photosensitive drum. Then, colored charged particles (hereinafter, referred to as toner) are applied by the developing device 113, and after a visualized image is obtained,
The transferred image is transferred to a recording medium taken out one by one from a sheet feeding cassette 120 by a sheet feeding roller 121 by a transfer charger 114. The transfer residual toner is wiped off from the surface of the photosensitive drum 112 by the cleaning device 115, and the photosensitive drum 112 prepares for the next image forming process.

On the other hand, the recording medium having the unfixed toner image thereon is inserted into the fixing device 116, and after a permanent fixed image is obtained, the recording medium is discharged out of the apparatus as a final print in the direction of the arrow in FIG. The arrow shown in the engine unit 102 is
4 illustrates a feeding locus of a recording medium taken out of a sheet feeding cassette 120 and conveyed.

The fixing device 116 in the laser beam printer as described above has a heater (fixing heater) 119 in the hollow fixing roller 117, and the fixing roller 117 is heated by energizing the heater 119. on the other hand,
The pressure roller 118 is pressed against the fixing roller 117 by urging means (not shown), and heats the unfixed toner on the recording medium together with the recording medium in a nip formed by the fixing roller 117 and the pressure roller 118. Permanent fixing is achieved by pressing.

Therefore, in order to perform satisfactory fixing, it is necessary to maintain the surface temperature of the fixing roller 117 at a predetermined appropriate temperature. Therefore, in this apparatus, as shown in FIG. 6, the temperature sensor 5 is mounted in contact with the fixing roller 117, and the temperature of the fixing roller 117 is detected by the temperature sensor 5. The output of the sensor 5 is input to the engine controller 105, and the temperature controller 105 turns on the fixing heater 119 using the fuser control unit 3.
/ OFF is controlled so that the surface temperature of the fixing roller 117 is maintained at a temperature necessary for heat fixing at the time of printing.

The temperature control by the engine controller 105 is performed not only at the time of printing but also at the time of start-up and at the time of standby, and control is performed at different temperatures. For example, since the fixing device takes a long time to warm up, the temperature is controlled so as to reach a predetermined standby temperature during standby, and when a print request is issued, the temperature of the fixing device is changed from the standby temperature to the required heat during the printing. The temperature has been raised to a temperature that allows fixing. In this standby mode, the temperature is controlled by turning on / off the heater 119.

FIG. 7 shows an example of temperature control during standby. FIG. 7 is a graph showing the relationship between the temperature T of the fixing device with the horizontal axis representing time t and the absolute value | I | of the fixing heater current. In the figure, T1 is the upper limit value of the standby temperature control,
T2 is a lower limit value of the standby temperature control. The engine controller 105 monitors the value of the temperature sensor 5 and starts energizing the fixing heater 119 when the temperature indicates the lower limit value T2, and ends energizing when the temperature reaches the upper limit value T1. Therefore, the energization time is between t ₀ and t ₁ as shown in FIG. On the other hand, since the heat stored in the fixing device gradually cools down, when the temperature again reaches the lower limit value T2, the heater 1
19 is energized. The time during which the temperature of the fixing device falls from the upper limit value T1 to the lower limit value T2 is between t ₁ and t _2.
Time from ₁ t _2, the length varies with elements constituting the changes and the fixing device of the surrounding air temperature. The engine controller repeats such control to perform temperature control during standby.

[0011]

[SUMMARY OF THE INVENTION However, the above conventional example, the fixing heater 119 of the fixing device 116 adopts the halogen heater using tungsten as filament, from t ₁ filament at time t ₂ When the temperature cools, the inrush current I as shown in FIG.
There is a problem that s flows.

In a halogen heater that radiates heat using a halogen cycle, the filament needs to be heated to a high temperature in order to increase the efficiency of the halogen cycle.
In this high temperature state, the specific resistance value of the tungsten is set to an optimum value. However, the specific resistance value of tungsten decreases as the temperature decreases, and the specific resistance value becomes very small at a low temperature before the heater is energized. Therefore, a large rush current flows when the heater is turned on as shown in FIG. As a result, it affects other devices that are supplying power from the same power supply line, and causes a flicker phenomenon of lighting devices, for example.

Further, in order to reduce this effect, the European Community (EC) has taken regulatory measures, and the EC EC standard E95
In N60555-3, the power supply voltage fluctuation value and the number of fluctuations are specified, but in order to conform to this standard, it is necessary to reduce the number of times the heater is turned ON / OFF repeatedly and the rush current value. In other words, the power supply voltage fluctuation value is defined by connecting a load having an impedance of 0.4 + 0.25j [Ω] to the power supply and the device under test in series, and defining the variation, and is consumed by the device under test. The power supply voltage fluctuation value increases as the current value increases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of solving the above-mentioned problems and reducing the number of intermittent driving of a heater and the rush current.

[0015]

According to the present invention, there is provided a heat fixing means for fixing colored charged particles on a recording medium by using a resistance heating element as a heat source, and a temperature of the heat fixing means. Means for detecting whether or not power is supplied to the resistance heating element based on the temperature detected by the temperature detection means.
By switching the electric, in an image forming apparatus and a temperature control means allowed to maintain respective different temperatures in the standby and during printing the temperature of the heat fixing means, temperature control means, against the said resistance heating element when it becomes a de-energized and
A counting means for counting the elapsed time from the image forming instrumentation
While waiting for the position, the time measured by the timer
Based on the temperature detected by the temperature detecting means,
During such becomes more than a predetermined time to a predetermined, waiting
And setting means for variably setting the upper limit temperature in the above.

[0016]

According to the present invention, during standby, the timer measures the elapsed time from when the power to the resistance heating element is turned off.
Is actually measured, and the time measured and the temperature detection means are detected.
At a predetermined time when the de-energization time is determined in advance based on the temperature
The maximum temperature during standby is variably set so that
Without lowering the standby temperature, and
Ensure that the de-energization time is longer than a predetermined time
Becomes Was, but I, the change and the fixing device of the surrounding air temperature
Even if the constituent elements are different, the resistance heating element
Prevents the resistance value from dropping extremely and energizes the resistance heating element
The inrush current generated at the time of
Reduce the number of times, and
The effect on other equipment being supplied is reduced.

[0017]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1> First, Embodiment 1 of the present invention will be described with reference to FIGS. The same parts as those of the conventional apparatus shown in FIG.

FIG. 4 is a block diagram showing an electrical configuration of the laser beam printer. In FIG. 4, reference numeral 1 denotes a power switch, which is used to turn on / off the power of the image forming apparatus. Numeral 2 denotes a noise filter for reducing noise generated by the image forming apparatus so as not to propagate to the AC line.

Reference numeral 105 denotes an engine controller.
A PU 105a, a RAM 105b, a ROM 105c, and a video I / F circuit 21. A series of control sequences for performing paper feed control of a recording medium, print control using an electrophotographic process, communication control with a video controller, and an engine. The control of each component of the unit and the exception handling control of the electrophotographic process sequence are performed.

Reference numeral 3 denotes a fuser control unit, which detects the temperature of a fixing heater 119 serving as a heat source for performing heat fixing by a temperature sensor 5 and turns ON / OFF so as to keep the temperature constant by a signal from an engine controller 105. Used for control. FIG. 1 shows the details of the circuit of the fuser control unit 3. As shown in FIG. 1, the fuser control unit 3 is provided with a triac and an SSR.
CPU 105a of engine controller 105 based on the temperature detected by temperature sensor 5
, A signal for turning ON / OFF the SSR is output. As a result, the conduction state of the triac is switched, and the current flowing through the heater 119 is controlled.

In FIG. 4, reference numeral 4 denotes a low-voltage power supply unit, which generates a voltage necessary for operating the image forming apparatus.

Reference numeral 6 denotes a fan motor, which is used to lower the temperature of the fixing device after printing and to suppress a rise in the temperature of each element forming the image forming apparatus. The rotation is controlled via the.

Reference numeral 8 denotes a light receiving element, which is a polygon mirror 10
The laser beam reflected at 8 is received, converted into an electric signal, and
The signal is transmitted to the D circuit 9. The BD circuit 9 shapes the signal and converts it into a horizontal synchronization signal to the video controller 103.
Tell For this reason, the light receiving element 8 is placed outside the photosensitive drum in the horizontal direction (main scanning direction), and generates a signal for each horizontal scanning.

Reference numeral 10 denotes a high-voltage power supply,
2, a primary charging voltage for primary charging, a developing voltage for developing a latent image generated on the photosensitive drum with toner, a transfer voltage for transferring the photosensitive drum to paper, and a separation for separating paper from the photosensitive drum. Generates voltage, etc. These voltages are applied to the primary charger 111 and the developing device 113 (developing cylinder and the like). The transfer and separation are performed by the transfer device 11.
4 (transfer roller), which is applied to a separator (not shown).
The engine controller 105 controls the timing at which these voltages are generated.

A scanner motor 11 reflects a laser beam generated by a laser diode 107 in a horizontal direction (main scanning direction) and applies a polygon mirror 108 to a latent image in the longitudinal direction of the photosensitive drum 112 to form a latent image. It is to rotate. The scanner motor driver 12 that controls the rotation of the polygon mirror 108 controls the rotation of the scanner motor 11 to be constant.

Reference numeral 13 denotes a main motor. The engine controller 105 outputs a signal from the main motor driver 14 to an O.
By performing N / OFF control, the photosensitive drum 112, the developing device 113, the transfer roller 114, the fixing roller 117,
The rotation control of rollers such as the pressure roller 118 and the conveyance roller (not shown) and the paper conveyance control are performed.

Reference numeral 16 denotes a paper presence / absence sensor, which is used by the engine controller 105 to detect the presence / absence of paper in a ready-to-feed state.

Reference numerals 18 and 19 denote a paper feed sensor and a paper discharge sensor, respectively, which are provided on a transport path for monitoring the transport state of the paper when the paper is transported and an electrophotographic process is performed. The paper feed sensor 18 is installed near the paper feed port,
The paper discharge sensor 19 is installed near the paper discharge port.

Reference numeral 20 denotes a cartridge sensor which is used to detect the presence or absence of a toner cartridge.

Reference numeral 22 denotes a pickup solenoid, which is an engine controller 105 for feeding sheets one by one.
Controlled by.

Reference numeral 107 denotes a laser diode. When a dot image created by the video controller 103 and converted into a video signal is transferred to the engine controller 105 through the video I / F circuit 21, the engine controller 105 The laser diode 107 is controlled by the driver 106 to adjust the intensity of the laser beam and perform modulation by a video signal.

As described above, the engine unit 102 is composed of components necessary for the image forming apparatus to output an image on paper by an electrophotographic process.

In FIG. 4, reference numeral 101 denotes a host I / F.
This circuit is used to control the reception of code data from the host computer and to input the code data to the video controller 103. Video controller 10
3 is a CPU 103a, a RAM 103b, a ROM 103
c, a buffer 103d, and a video I / F circuit 21. Code data from the host computer is developed into a dot image, the data is stored in the buffer 103d, and the dot image is sent to the engine controller 105 through the video I / F circuit 21. Transfer control. In addition, display control and input control of the display / operation panel 104 are also performed. 10
3f is a nonvolatile storage medium (NVRAM, EEPROM
, Etc.), and stores initial information necessary for controlling the image forming apparatus. That is, the user operates the display / operation panel 1
This is for storing various types of information set by using the command line 04 and information set by the control program of the image forming apparatus even after the power is turned off, so that the set state can be restored when the system is restarted. .

Next, a basic printing operation in the image forming apparatus will be described. First, a program (built in the ROM 103c) for controlling the video controller 103 of the image forming apparatus inputs code data created by the host computer through the host I / F circuit 101 of the image forming apparatus. The input code data is sequentially stored in the RAM 103b or the buffer 103 of the video controller 103.
d, the program of the video controller 103 decodes the code data, develops it into a dot image, and stores the image data in the buffer 103d. And
After developing one page of code data into a dot image, the video I /
A print request is made through the F circuit 21.

Upon receiving the print request, the engine controller 105 starts up the components constituting the engine unit 102. First, the control of the fixing heater 119 is started so that the temperature of the fixing device becomes a fixable temperature, and the rotation control of the main motor 28 and the scanner motor 11 is started.
Further, the laser driver is controlled so that the laser light amount becomes a predetermined light amount. Then, when the adjustment of the scanner motor 11 and the laser light amount is completed, the signal detected by the light receiving element 8 is shaped as a BD signal by the BD circuit 9, and this signal is monitored to determine whether there is any abnormality. As a result, when it is determined that there is no abnormality in the control of each of these elements, it is determined from the signal of the paper presence / absence sensor 16 that there is paper in the paper feed cassette and paper can be fed, and then the pickup solenoid 22 is operated. Turn ON to feed paper. Then, the timing at which the fed paper passes the paper feed sensor 18 is detected, and the leading edge synchronization signal (vertical synchronization signal) of the paper and the horizontal synchronization signal (BD) are sent to the video controller 103.
Signal).

Thus, the video controller 103
Sends the dot image as a video signal for each column in the horizontal direction to the engine unit 102 in synchronization with the synchronization signal in the vertical and horizontal directions. The engine controller 105 includes an area where an image can be formed on paper (image printable area) and the light receiving element 8.
Mask the video signal so that the laser diode 107 does not emit light except at the timing of detecting the laser light in
Laser driver 106 based on the masked video signal
The laser light is modulated by the laser diode 107.
As a result, the laser light is reflected by the polygon mirror 108 and exposes the photosensitive drum 112.

On the other hand, the engine controller 105 controls the high-voltage power supply 10 to generate a primary charging voltage prior to the above exposure, and uniformly charges the surface of the photosensitive drum 112 so that an image can be formed from the leading edge of the paper. Let it. The above-described exposure is performed on the charged photosensitive drum 112 to form an electrostatic latent image on the photosensitive drum 112. Further, the electrostatic latent image moves to a position facing the developing device 113 with the rotation of the photosensitive drum 112 and is visualized by toner. That is, a developing voltage is applied to the developing cylinder of the developing device 113 by the high-voltage power supply 10, and the toner contained in the developing device 113 is moved toward the photosensitive drum 112 by the action of the electric field to perform the developing. Will be Then, the developed image is further moved to a portion facing the transfer charger 114 by rotation of the photosensitive drum 112, and is transferred onto paper conveyed to the facing portion by the transfer voltage applied by the high voltage power supply 10. The paper is separated from the photosensitive drum 112 by the separation voltage applied by the high voltage power supply 10.

The paper thus transferred and separated is guided to a fixing device and is fixed by heat and pressure fixing. After fixing, the paper is discharged from a discharge port. In this embodiment, an image is formed on paper through such a process.

In the image forming apparatus of the present embodiment as described above, the fixing device is heated at a low temperature during standby in order to shorten the printing start time from standby. For this reason, the engine controller 105 judges the input value from the temperature sensor 5 and turns on / off the fixing heater so that the fixing device maintains a predetermined low temperature.

In this embodiment, temperature control during standby is performed as shown in the flowchart of FIG. Hereinafter, a description will be given with reference to graphs of the temperature T and the absolute value | I | of the current flowing through the heater shown in FIGS. In FIG. 3, T1 is the maximum temperature when the heater is turned on during the conventional standby temperature control. T2 is a standby lower limit temperature, and lighting control of the heater is performed so that the temperature becomes higher than this temperature during standby. Furthermore, T3 can while OFF the heater from time t ₃ to time t _4, a temperature which allowed to lower the temperature of the heater to a temperature slightly higher than the temperature T2. T4 is the temperature when the heat radiation ratio is higher than T3.
T5 is the maximum temperature of the heater set at the time of printing.

In this embodiment, when it is detected at time t ₀ that the detected temperature has dropped below the temperature T 2, the heater is turned on and turned on until time t ₃ , and the temperature of the heater is raised to temperature T 3. Then, after a predetermined time has elapsed, the heater is turned off,
When the natural heat dissipation up to time t _4, so again the detected temperature after time t ₄ elapses is lower than the temperature T2, the heater O
N and repeat the above process. The time t ₃ to t ₄ is controlled by a timer and is always the same time. If the temperature of the fixing device becomes T2 or less before the time t ₄ ,
The control is performed by raising the temperature of the heater ON to T4.

That is, in the present embodiment, the upper limit temperature during standby is set higher than in the prior art, so that the energization interval to the heater is made longer than in the prior art to reduce the number of times the heater is turned on and off. By making the temperature during the heater OFF period higher than in the past, a decrease in the resistance value of the heater is prevented, and the rush current is reduced.

Next, the temperature control of this embodiment will be described with reference to the flowchart of FIG. First, after the power is turned on and the warm-up sequence is performed, the process proceeds to the standby sequence, and the standby temperature control is started (S
0). At this time, the temperature of the heater has warmed to T2 (standby lower limit temperature) or more during warm-up. Next, the control ROM103c, interval ON the heater had been stored in a nonvolatile storage medium 103f such video controllers (interval t ₄ from t _3), said control ROM103c
And the like, and set a timer value (S1).
Then, the timer is started (S2), and it is determined whether or not the timer has exceeded the set value (S3). If not, it is determined whether or not the input value of the temperature sensor 5 has become T2 or less (S4). If the input value is higher than the temperature T2, the monitoring of the timer is continued (S4 to S3).
If it is not more than 2, a new temperature adjustment temperature T3 is set by adding ΔT to the temperature adjustment temperature T3 of the fixing heater (S5). This new temperature regulation temperature T3 corresponds to the temperature T4 in FIG. 3 and must be kept within a range not exceeding the maximum temperature T5.
Therefore, the temperature T3 is determined whether higher than the maximum temperature T5 (S6), reducing the timer value temperature T3 is determined the interval t ₄ from t ₃ if the maximum temperature T5 higher (S7), With this, control is performed so that the temperature does not drop below the standby lower limit temperature. If the new temperature control temperature T3 is lower than the maximum temperature T5, the heater is immediately turned on (S
6 to S8). When the heater is turned on, the temperature sensor 5 is monitored, and control is performed so that the temperature of the fixing device does not exceed the temperature regulation temperature T3 (S9 to S10). That is, when the detected temperature is the temperature control temperature T
If it exceeds 3, the heater is turned off, and the process returns to the timer start routine to repeat the control (S10 to S2). On the other hand, in the timer check routine, if it exceeds the set value of the timer, that is, when it reaches the t _4, to check the temperature of the fixing device (S3 through S11), raising the temperature adjustment temperature T3 if T2 or less ( S11-S5), T if T2 or more
The value of 3 is decreased (S12), and the control is repeated by turning on the heater in the same manner as described above.

As described above, according to the temperature control of the present embodiment, even when the ambient temperature changes and the components constituting the fixing device are different, the heater ON / O is always performed at a constant interval.
By performing the FF, the heater OFF period is maintained at a higher temperature than in the past, so that an extreme decrease in the resistance value of the fixing heater can be prevented, and an increase in the rush current can be prevented.

<Embodiment 2> Next, Embodiment 2 of the present invention will be described. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description is omitted.

In the first embodiment, the lower limit temperature is fixed. However, if the user determines that the time required to shift from the standby state to the print state may be longer, the user operates the operation panel to operate the temperature T2. Turn off the heater or turn off the heater by extending the timer setting value without setting it.
The intervals at which they are performed may be widened.

Third Embodiment Next, a third embodiment of the present invention will be described. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description is omitted.

Information necessary for control such as the set value of the temperature control temperature T3 and the set value of the timer shown in the first and second embodiments is always stored in the nonvolatile storage medium, and after the power is turned off and restarted, Alternatively, the setting value may be read from the non-volatile storage medium, and control may be performed based on this information. Alternatively, the stored contents may be input from an operation panel or the like, and the temperature control may be performed by changing control parameters based on the input contents.

Embodiment 4 Next, Embodiment 4 of the present invention will be described. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description is omitted.

The timer set value described in the third embodiment may not necessarily be set in the non-volatile storage medium, but may be always returned to the initial state at the time of startup to prevent the timer set value from becoming too short.

Fifth Embodiment Next, a fifth embodiment of the present invention will be described. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description is omitted.

In the first embodiment, the heater is turned off and then turned on.
Although the time until the heater is controlled by the timer, the time from when the heater is turned on to when the heater is next turned on may be controlled by moving the place where the process for starting the timer (S2 in FIG. 2) is inserted. .

[0054]

As described above, according to the present invention,
Oite while waiting, counting means pair to the de-energized the resistive heating element
The actual time elapsed since the
Is de-energized based on the time
Wait until the time is longer than the predetermined time
Since the upper limit temperature in the middle is variably set , the temperature during standby
Without deteriorating, and reliably, the non-energizing time
Can be set to a predetermined time or more . I
Therefore, changes in the ambient temperature and the structure of the fixing device are considered.
Even if the formed elements are different, while suppressing an increase in inrush current generated distinctive low resistance value of the resistance heating element when energized proof sealed by resistance heating element, reducing the number of inrush current can be, electrodeposition from the same power supply as the image forming apparatus
It is possible to reduce the influence that pairs to other devices receiving power supply.

[Brief description of the drawings]

FIG. 1 is an electric block diagram of a heater control unit in an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating temperature control during standby in the image forming apparatus according to the first exemplary embodiment of the present invention.

FIG. 3 is a diagram illustrating a temperature change during standby and a change in an absolute value of a current flowing through a heater in the image forming apparatus according to the first embodiment of the present invention.

FIG. 4 is an electric block diagram of the image forming apparatus according to the first embodiment of the present invention.

FIG. 5 is a side sectional view showing a schematic configuration of a conventional image forming apparatus.

FIG. 6 is an electric block diagram of a conventional image forming apparatus.

FIG. 7 is a diagram illustrating a temperature change during standby and a change in an absolute value of a current flowing through a heater in a conventional image forming apparatus.

FIG. 8 is a diagram illustrating an inrush current flowing through a heater in a conventional image forming apparatus.

[Explanation of symbols]

 Reference Signs List 3 fuser control unit (energization switching unit) 5 temperature sensor (temperature detection unit) 105 engine controller (temperature control unit) 116 fixing device (thermal fixing unit) 119 fixing heater (resistance heating element)

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Kenjiro Hori 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-4-287080 (JP, A) JP-A-5 JP-A-158381 (JP, A) JP-A-2-244179 (JP, A) JP-A-2-64590 (JP, A) Japanese Utility Model Application No. Sho 63-113170 (JP, U) Japanese Utility Model Application Laid-open No. 1-88964 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) G03G 13/20 G03G 15/20

Claims (5)

(57) [Claims] 1. A thermal fixing means for fixing colored charged particles on a recording medium by using a resistance heating element as a heat source, a temperature detecting means for detecting a temperature of the thermal fixing means, and a detection by the temperature detecting means. passing to the resistance heating element based on the temperature
By switching the electric and de-energized, in an image forming apparatus and a temperature control means allowed to maintain the temperature of the heat fixing means at different temperatures in the standby and during printing, the temperature control means, the resistance heating elapsed from when paired with a non-energized to the body
A time measuring means for measuring time, and a time measuring means for counting the time while the image forming apparatus is on standby.
Time and the temperature detected by the temperature detecting means.
Te, so that the predetermined time or more of the non-energization time is predetermined, set for variably setting the upper limit temperature during standby
An image forming apparatus comprising: the means. 2. The method according to claim 1, wherein the setting means is configured to determine that the timing means is in the location.
When measuring a constant time, when the detection temperature of the temperature detection means is equal to or higher than the lower limit temperature is set again to lower the maximum temperature
The image forming apparatus according to claim 1, wherein to Rukoto. 3. The apparatus according to claim 2, further comprising : an operating means , wherein said setting means is configured to control a lower limit during standby based on an operation of said operating means.
The image forming apparatus according to claim 1 or claim 2, wherein the temperature is a settable. 4. The method according to claim 1, further comprising :
At least one of the upper limit temperature , the lower limit temperature, and the predetermined time.
The image forming apparatus according to any one of claims 1 to 3, characterized in that have a non-volatile memory means for storing One. 5. The temperature control means according to claim 1, wherein:
Even if a predetermined maximum value is set as the upper limit temperature,
The temperature is detected before the timer measures the predetermined time.
If the temperature detected by the means is below the lower limit,
The image forming apparatus according to claim 1, further comprising a time setting unit configured to set the image forming apparatus to a shorter time .