JPH11242404A - Device and method for flicker suppression - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce flickers of lightness of a luminaire, a television, etc., connected to the same power supply system. SOLUTION: When the power source is turned ON, a CPU 3 takes a normal turn-on time out of a RAM 1, sets 240 mn as the turn-ON time of the main heater 901 and 160 mn as the turn-ON time of a subheater 902 in a heater control part 4 and a heat-up process is performed. When a standby mode entered after the heat-up process ends, the CPU 3 takes a changed turn-ON time out of the RAM 1 and sets 7200 mn as the turn-ON time of the main heater 901 and 4800 ms as the turn-ON time of the subheater 902 in the heater control part 4. With a copy start key 5 pressed, the CPU 3 takes the normal turn-ON time out of the RAM 1 and sets 240 mn as the main heater turn-ON time and 160 mn as the subheater turn-ON time in the heater control part 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for suppressing flicker in an electronic apparatus, for example, an image recording apparatus such as a copying machine or a printer having a fixing heater.

[0002]

2. Description of the Related Art In a conventional image recording apparatus, for example, a copying machine having a main heater and a sub heater as a fixing heater, every time the detected temperature of the fixing roller becomes lower than the target temperature,
For example, the main heater is turned on for 240 ms, and the sub heater is turned on for 160 ms.

[0003]

The lighting time of the fixing heater is constant and does not change during the standby or the copy sequence.
As shown in FIG. 10, it will be repeated frequently.
Therefore, both during standby and during the copy sequence, the voltage on the power supply line to the fixing heater is frequently changed, and the lighting equipment and the television connected to the same power supply system have a flickering brightness, which is annoying. I felt it. The flicker that humans perceive is called flicker. It is desired to reduce this flicker.

A first object of the present invention is to solve the above-mentioned problems and to reduce flicker in brightness of lighting equipment, televisions and the like connected to the same power supply system, and a flicker suppressing apparatus. It is to provide a method.

A second object of the present invention is to provide a flicker suppressing apparatus and method for controlling a main heater and a sub-heater to reduce flicker during standby of equipment as much as possible.

A third object of the present invention is to provide a flicker control device and method which reduce the number of power fluctuations during standby to reduce flicker.

A fourth object of the present invention is to provide a flicker suppressing apparatus and method which reduce flicker by changing a single lighting time of a heater according to the operation state of an image forming apparatus.

[0008]

According to a first aspect of the present invention, there is provided a flicker suppressing device in an image forming apparatus, a fixing device having a heating element, a temperature detecting device for detecting a temperature of the fixing device, and the temperature detecting device. Temperature control means for controlling the driving of the heating element by a pulse signal of a predetermined period so that the temperature detected by the control means becomes the target temperature, wherein the temperature control means controls the number of power fluctuations in the image forming standby state. The period of the pulse signal in the standby state is made longer than the period of the pulse signal during the image forming operation in order to reduce the time.

In the first aspect, the fixing device can have first and second heating elements, and the temperature control means includes:
For each of the first and second heating elements, the period of the pulse signal in the standby state can be longer than the period of the pulse signal during the image forming operation.

[0010] According to a second aspect of the present invention, the temperature control means is configured to turn on the first heating element during standby by comparing the on-time of the first heating element and the on-time of the second heating element during image formation. The time and the ON time of the second heating element can be lengthened.

According to a fourth aspect of the present invention, in the flicker suppressing device in the image forming apparatus, a fixing device having a heating element, a temperature detecting means for detecting a temperature of the fixing device, and a control indicating a time during which the heating element is turned on. A memory that stores data, and a temperature control unit that controls driving of the heating element by a pulse signal of a predetermined cycle based on control data read from the memory so that the temperature detected by the temperature detection unit becomes a target temperature. In order to reduce the number of power fluctuations in the standby state where image formation is possible,
The ON time of the control data in the standby state is longer than the ON time of the control data during the image forming operation.

According to a fourth aspect of the present invention, the fixing device may have first and second heating elements, and the temperature control means may include a first heating element.
For each of the second heating element and the second heating element, the cycle of the pulse signal in the standby state can be longer than the cycle of the pulse signal in the image forming operation.

According to a fifth aspect of the present invention, the temperature control means is configured to compare the ON time of the first heating element during standby with the ON time of the first heating element during image formation and the ON time of the second heating element. The on time of the heating element 2 can be lengthened.

According to a seventh aspect of the present invention, there is provided an image forming apparatus comprising: a fixing device having a heating element; a temperature detecting means for detecting a temperature of the fixing device; and a memory storing control data indicating a time for turning on the heating element. In the flicker suppressing method in the forming apparatus, when the image forming apparatus enters a standby state in which an image can be formed, a first reading step of reading out first control data representing an ON time in the standby state from the memory, and the temperature detecting unit detects the first control data. Temperature is first
A first driving step of driving the heating element by a pulse signal of a predetermined cycle based on the first control data read in the first reading step so that the target temperature is reached, and an image forming operation is started. A second reading step of reading second control data representing an ON time during image formation from the memory, and the second reading step such that a temperature detected by the temperature detecting means becomes a first target temperature. A second driving step of driving the heating element with a pulse signal of a predetermined cycle based on the second control data read in the step, and a pulse signal in a standby state for reducing the number of power fluctuations in a standby state. Is longer than the period of the pulse signal at the time of image formation.

[0015] In claim 7, the fixing device may have first and second heating elements, and in the first and second driving steps, reading is performed for the first and second heating elements, respectively. The first and second heating elements can be driven by a pulse signal having a predetermined cycle based on the control data.

In claim 8, the on-time of the first heating element and the on-time of the second heating element during standby are determined by the on-time of the first heating element and the on-time of the second heating element during image formation. It can be longer than the time.

According to a tenth aspect of the present invention, there is provided a fixing device having a heating element, a temperature detecting means for detecting a temperature of the fixing device,
A flicker suppressing device in the image forming apparatus, comprising: a temperature control unit that controls driving of the heating element so that the temperature detected by the temperature detection unit becomes a target temperature. In order to reduce the number of power fluctuations in the standby state, the off time of the heating element in the standby state is set to a fixed time longer than the off time of the heating element in the image forming operation.

According to a tenth aspect, the temperature control means can change the off time of the heating element according to the target temperature during standby.

According to a tenth aspect of the present invention, the apparatus may further include a memory storing data indicating the off time of the heating element, and the temperature control means may control the driving of the heating element based on the data read from the memory. .

According to a tenth aspect of the present invention, the fixing device may have first and second heating elements, and the temperature control means may set an off time during standby for each of the first and second heating elements. Can be set independently.

According to a tenth aspect of the present invention, the temperature control means can cancel the setting of the off-time at the standby time when the image forming operation is started.

According to a fifteenth aspect of the present invention, there is provided a fixing device having a heating element, temperature detecting means for detecting a temperature of the fixing device,
A flicker suppressing method in the image forming apparatus, comprising: a temperature controller that controls driving of the heating element so that the temperature detected by the temperature detector becomes a target temperature.
A determining step of determining whether or not the image forming apparatus is in a standby state in which an image can be formed; and, if determining that the image forming apparatus is in a standby state, setting an off time of the heating element in a standby state to the heating element in an image forming operation. A setting step of setting a fixed time longer than the off time, and controlling the driving of the heating element based on the set off time so that the temperature detected by the temperature detecting means becomes a target temperature during standby. And a control step of performing

[0023] In claim 15, in the setting step,
The off time of the heating element can be changed according to the target temperature during standby.

According to a fifteenth aspect, the image forming apparatus can have a memory storing data indicating the off time of the heating element, and in the setting step, the off time can be set based on the data read from the memory. .

According to a fifteenth aspect, the fixing device can have first and second heating elements, and in the setting step, the first and second heating elements have independent off-time during standby. Can be set to

According to a fifteenth aspect, it is possible to further include a release step of releasing the off-time set in the setting step when the image forming operation is started.

According to a twentieth aspect of the present invention, there is provided a fixing device having a heating element, temperature detecting means for detecting the temperature of the fixing device, and driving of the heating element such that the temperature detected by the temperature detecting means becomes a target temperature. In the flicker suppression device in the image forming apparatus having a temperature control unit that controls the temperature control unit, the temperature control unit, in order to reduce the number of power fluctuations in a standby state in which an image can be formed, the off time of the heating element during standby, It can be set to a fixed time longer than the off time of the heating element during the image forming operation.

In the twentieth aspect, the temperature control means can change the off time of the heating element according to the target temperature during standby.

According to a twentieth aspect of the present invention, the apparatus may further include a memory storing data indicating the off time of the heating element, and the temperature control means may control the driving of the heating element based on the data read from the memory. .

[0030] In the twentieth aspect, the fixing device may have first and second heating elements, and the temperature control means may include:
The off-time during standby can be set independently for each of the first and second heating elements.

In the twentieth aspect, the temperature control means can cancel the setting of the off time in the standby state when the image forming operation is started.

[0032]

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

<First Embodiment> FIG. 1 shows a first embodiment of the present invention.
An embodiment will be described. This is an example of a copying machine, and its structure is shown in FIG. The copying machine includes a color reader unit and a printer unit.

The color reader will be described. In FIG. 2, reference numeral 302 denotes a document feeder (DF) for feeding a document to a platen glass (platen) 301. 303
Reference numerals 304 and 304 denote light sources (halogen lamps or fluorescent lamps) for illuminating a document on the document table glass 301. 305 and 306 are reflecting umbrellas, and light sources 303,
The light 304 is focused on the document. 314
Denotes a carriage, which accommodates halogen lamps 303 and 304, reflectors 305 and 306, and a mirror 307.
A carriage 315 accommodates mirrors 308 and 309.

The reflected light (or transmitted light) from the original on the original platen glass 301 is guided to the condenser lens 310 by mirrors 307 to 309, and is transmitted to the condenser lens 310 by the condenser lens 310.
It is guided on D101. The CCD 101 is mounted on a substrate 311 and converts an optical signal into an electric signal.
The carriage 314 moves at a speed V and the carriage 315 moves at a speed V / 2 in a direction perpendicular to the electrical scanning (main scanning) direction of the CCD 101, thereby scanning the entire surface of the document (sub scanning). An image processing unit 312 drives and controls the CCD 101 and processes the obtained electric signal. Reference numeral 313 denotes an interface (I / F) with another IPU or the like.

The printer section will be described. In FIG. 2, 3
Reference numerals 40 and 441 denote cassettes for storing recording paper. 338 and 339 are pickup rollers for picking up recording sheets one by one from the cassettes 340 and 341 respectively. 336,337
Denotes paper feed rollers, and pickup rollers 338 and 33
9 supplies the recording paper picked up to the transfer belt 333. Reference numeral 446 denotes an attraction charger, which charges the recording paper fed by the paper feed rollers 336 and 337 in cooperation with the transfer belt roller 448 that drives the transfer belt 333. Reference numeral 447 denotes a paper leading edge sensor for detecting the leading edge of the recording paper on the transfer belt 333. The detection signal from the paper leading edge sensor 447 is sent from the printer unit to the color reader unit, and is used as a sub-scan synchronization signal when a video signal is sent from the color reader unit to the printer unit.

Reference numeral 317 denotes an M (magenta) image forming unit;
8 is a C (cyan) image forming unit, 319 is Y (yellow)
An image forming unit 320 is a K (black) image forming unit, and is arranged from the upstream side to the downstream side so as to face the transfer belt 333. M image forming section 317, C image forming section 318, Y image forming section 319, K image forming section 32
In the case of 0, the configurations are essentially the same except that the colors of the developers of the developing units 322, 325, 328, and 331 are different.

The M image forming section 317 includes a primary charger 321
When the surface of the photosensitive drum 341 is charged to a predetermined potential to prepare for the formation of a latent image, the LED array 210 is driven based on the first color image data to scan the photosensitive drum 341 and the latent image is formed on the surface. And develops the latent image into a developing device 3
22 to form an M toner image. Note that the developing device 322 includes a sleeve 345 for applying a developing bias to perform development. Then, discharge is performed from the rear surface of the transfer belt 333 by the transfer charger 323, and the M toner image on the photosensitive drum 341 is transferred to the recording paper on the transfer belt 333.

The C image forming section 318 includes a primary charger 324
When the surface of the photosensitive drum 342 is charged to a predetermined potential to prepare for latent image formation, the LED array 211 is driven based on the first color image data to scan the photosensitive drum 342, and the latent image is formed on the surface. And develops the latent image into a developing device 3
25 to form a C toner image. The developing device 325 includes a sleeve 346 for applying a developing bias to perform development. Then, discharge is performed from the back of the transfer belt 333 by the transfer charger 326, and the C toner image on the photosensitive drum 342 is transferred to the recording paper on the transfer belt 333.

The Y image forming section 319 includes a primary charger 327
When the surface of the photosensitive drum 343 is charged to a predetermined potential to prepare for latent image formation, the LED array 212 is driven based on the first color image data to scan the photosensitive drum 343, and the latent image is formed on the surface. And develops the latent image into a developing device 3
28 to form a Y toner image. Note that the developing device 328 includes a sleeve 347 for applying a developing bias to perform development. Then, discharge is performed from the back of the transfer belt 333 by the transfer charger 329 to transfer the Y toner image on the photosensitive drum 343 to recording paper on the transfer belt 333.

The K image forming section 320 includes a primary charger 330
When the surface of the photosensitive drum 344 is charged to a predetermined potential to prepare for latent image formation, the LED array 213 is driven based on the first color image data to scan the photosensitive drum 344, and the latent image is formed on the surface. And develops the latent image into a developing device 3
31 to form a K toner image. Note that the developing device 331 includes a sleeve 348 for applying a developing bias to perform development. Then, discharge is performed from the rear surface of the transfer belt 333 by the transfer charger 332, and the K toner image on the photosensitive drum 344 is transferred to the recording paper on the transfer belt 333.

Reference numeral 349 denotes a static eliminator, which neutralizes the recording paper to facilitate separation of the recording paper having passed through the K image forming section 320 from the transfer belt 333. 350
Reference numeral denotes a peeling charger for preventing an image from being disturbed by peeling discharge when the recording paper is separated from the transfer belt 333. Reference numerals 351 and 352 denote pre-fixing chargers for charging the recording paper separated from the charging belt 333 in order to supplement the toner attraction force and prevent image disturbance. Reference numeral 334 denotes a fixing device, and the fixing heater 90
Rollers 903 and 9 warmed by 1 and 902
This is to heat-fix the toner image on the recording paper by the heat of 04. 335 is a paper discharge tray for receiving the discharged recording paper.

Referring to FIG. In FIG. 1, 1 is RA
M (random access memory), which stores a heater lighting time setting table. 6 is ROM (read only me)
mory), and the control program is stored. Reference numeral 3 denotes a CPU (central processing unit).
The control program detects whether the state of the copying machine is in the heat-up state, in the standby state, or in the copying operation. The heater ON time and the light OFF time corresponding to the state of the copying machine detected by the CPU 3 or the cycle of the heater driving pulse are stored in the RAM 1.
From the heater turn-on time setting table of FIG. 4 is a heater control unit,
The CPU 3 drives and controls the fixing heaters 901 and 902 based on the lighting time and cycle set out of the RAM 1 by the CPU 3.

FIG. 3 is a flowchart showing an example of the control program stored in the ROM 6 shown in FIG. When the power is turned on, in step S201, data of the normal lighting time and cycle of the fixing heater is extracted from the RAM 1, and 240 ms is set as the lighting time of the main heater 901 in the heater control unit 4, and the lighting time of the sub heater 902 is set. Is set to 160 ms, and in step S202, the heater control unit 4 causes the heater to heat up.
The timing of the sub heater 902 is controlled so as not to be turned on in parallel with the main heater 901.

When the heating up by the heater control section 4 is completed, the process proceeds to step S203, and the process proceeds to step S203.
At 203, it is determined whether or not the copying machine is in a standby state, which is a copying standby state. If not, the process proceeds to step S204, and in step S204, it is determined whether the copying machine is in a copying operation. If the copying operation is being performed, the process returns to step S203. If the copying operation is not being performed, this control is terminated.

On the other hand, if the result of determination in step S203 is that the apparatus is on standby, the flow proceeds to step S205. In step S205, the data of the changed lighting time and cycle of the fixing heater is extracted from the RAM 1 and is given to the heater controller 4 as 720 as the lighting time of the main heater 901.
0 ms is set, and the lighting time of the sub-heater 902 is set to 4
800 ms is set, and in step S206, the process waits until the copy start key 5 is pressed. Also in this case, the timing of the sub heater 902 is controlled so as not to be turned on in parallel with the main heater 901. Then, when the copy start key 5 is pressed, the process proceeds to step S207, and in step S207, data of the normal lighting time and cycle of the fixing heater is extracted from the RAM 1 and the main heater 9 is read.
The lighting time of 01 is set to 240 ms, the lighting time of the sub-heater 902 is set to 160 ms, and the process returns to step S203.

Since it is not necessary to control the temperature of the fixing heater with higher precision during standby than during copying, as described above, the lighting time of the main heater 901 is set to 7200 ms and the lighting time of the sub heater 902 is set to 48 during standby.
Since the number of times of lighting is reduced instead of extending the lighting time of the heater by controlling so as to be 00 ms, the power fluctuation with respect to the main heater control signal and the sub heater control signal is as shown in FIG. As can be seen from FIG. 4, the power fluctuation width is reduced, and the number of power fluctuations can be dramatically reduced. Therefore, IEC555-3 (IEC10-00-3), which regulates voltage fluctuation and flicker in a commercial power supply system due to switching of an electric load of an electric / electronic device.
-3) The flicker standard value can be cleared.

In the present embodiment, an example of an image recording apparatus having two fixing heaters has been described. However, the same effect can be obtained with one fixing heater.

Further, by changing the lighting time of the main heater 901 and the lighting time of the sub-heater 902 during the image recording operation and during the standby, the number of power fluctuations can be drastically reduced. The flicker standard value can be cleared by reducing the number of voltage fluctuations in the system.

FIG. 5 is a sectional view of the fixing device. In FIG. 5, 11 is a fixing main heater, 12 is a fixing sub-heater,
13 is a thermistor, 14 is a thermostat, and 15 is a fixing roller.

<Second Embodiment> FIG. 6 shows the relationship between the power fluctuation a when the fixing heater OFF time is controlled in accordance with the sequence, the fixing main heater control signal b, and the fixing sub-heater control signal c. This will be described below in accordance with specific operations.

In this embodiment, the off time of the fixing heater is set while the image forming apparatus is on standby. For example, if the temperature control temperature is 190 ° C., the off time of the fixing main heater (500 W) is set to 10000 m as shown in the table of FIG.
s (shown by A in FIG. 6), and the fixing sub-heater (60
0 W) of 13000 ms (shown by B in FIG. 6)
Set to. The data of the OFF time of each heater shown in FIG. 6 is stored in the ROM 6 of FIG. Since the off time of the heater in the standby state is set sufficiently long as compared with the driving cycle of the heater in the image forming operation, the number of times of lighting of the entire fixing heater can be reduced. If you ’re on standby,
Since it is not necessary to always maintain the surface temperature of the fixing roller at the temperature regulation temperature, there is no problem in this control.

However, if the controlled temperature during standby is not ensured to some extent, the amount of heat required for fixing cannot be secured immediately after the copy start key is pressed. As shown in the heater off time characteristic table, the off time of the fixing heater is appropriately changed depending on the heater power and the temperature.

The lighting time of the fixing main heater and the fixing sub-heater during standby is determined by whether or not the temperature reaches the temperature regulation temperature (the lighting time is not controlled in this case). That is, once each fixing heater is turned on, it is turned on until the temperature reaches the regulated temperature, and when the temperature reaches the regulated temperature, the fixing heater is turned off and the set off time is counted.

As shown in FIG. 6, when the copy start key 5 is pressed to start copying during the counting of the off time, the counting of the off time is canceled (shown by A "and B" in FIG. 6). ).

As described above, by controlling the OFF time of the fixing heater, the number of times the fixing heater is turned on as a whole can be reduced. Accordingly, since the number of times of power fluctuation can be drastically reduced, the flicker standard value can be cleared.

The value of the off-time in the present embodiment is an example, and the value changes depending on the examination. Further, the same effect can be obtained even with a single fixing heater.

FIG. 8 is a flowchart showing an example of the flicker countermeasure control procedure. When the power is turned on, S2
At 01, the fixing heater is simultaneously turned on to heat up the fixing heater, and the lighting time during normal copying is set. Then, in S202, the process waits until the heating up of the fixing heater is completed (until the temperature reaches the temperature regulation temperature). Upon completion of the heating up of the fixing heater, S203
It is determined whether or not the image forming apparatus is in a standby state.
If it is determined that the standby state has been set, the process proceeds to step S205 where RO
The fixing heater off time read from M6 is set (this step will be described later with reference to FIG. 9).
At 206, the process waits until the copy start key 5 is pressed. When the copy start key 5 is pressed, S
At 207, the lighting time of the fixing heater is reset (off-time setting is released), and at 204, the process waits until the copying operation is completed. When the copy operation is completed, S2
At 08, it is determined whether or not the apparatus is in the standby state. If it is determined that the apparatus is not in the standby state, the control is thereafter terminated. On the other hand, if it is determined that the apparatus is in the standby state, S2
Go to 05.

On the other hand, if it is determined in S203 that the image forming apparatus is not in the standby state, the process proceeds to S204.

FIG. 9 is a flowchart showing a control procedure when the OFF time of the fixing heater is set. S40
When the off time of the fixing main heater 11 and the fixing sub-heater 12 is set in the standby state in S1, the process proceeds to S40.
At 2, it is determined whether or not the temperature of the fixing device has reached the temperature regulation temperature. If it is determined that the temperature has reached the regulated temperature,
At 403, the main heater 11 is turned off, the sub-heater 12 is turned on, and the counting of the main heater off time set at S401 is started. And S404
In, it is determined whether the copy start key 5 is pressed,
If it is determined that the copy start key 5 has not been pressed, in S405, the main heater 11 is forcibly maintained in the OFF state until the counting is completed. Then, S40
Return to 2. On the other hand, if it is determined that the copy start key 5 has been pressed, in step S408, the heater off time setting is released, and then this processing ends.

On the other hand, if it is determined in S402 that the temperature of the fixing device 334 has not reached the temperature regulation temperature, the main heater 11 is turned on in S406. And S407
It is determined whether or not the temperature has reached the regulated temperature. If it is determined that the temperature has reached the regulated temperature, the process proceeds to S403. If it is determined that the temperature has not been reached, the process returns to S406.

While the main heater 11 has been described above, the sub heater 12 is controlled in the same manner as the main heater 11.

By performing the above control, the flicker standard can be cleared.

As described above, the storage medium storing the program codes of the software for realizing the functions of the above-described embodiment is supplied to the system or the apparatus, and the computer (or CPU or MP) of the system or the apparatus is supplied.
It goes without saying that the object of the present invention is also achieved when U) reads out and executes the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the novel function of the present invention, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM
(Compact disk ROM), CD-R (compact disk recor)
dable), magnetic tape, nonvolatile memory card, ROM
(Read only memory), and so on.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS running on the computer based on the instruction of the program code.
It goes without saying that an operating system or the like performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function is executed based on the instruction of the program code. The CPU provided on the expansion board or function expansion unit performs part or all of the actual processing,
It goes without saying that the processing may realize the functions of the above-described embodiments.

The present invention is not limited to the above-described embodiment, but can be variously modified within the scope shown in the claims.

[0070]

As described above, according to the present invention,
With the configuration as described above, it is possible to reduce the flickering of the brightness of a lighting fixture, a television, or the like connected to the same power supply system.

Further, according to the present invention, the main heater and the sub-heater are controlled respectively, and flicker during standby of the apparatus can be reduced as much as possible.

Further, according to the present invention, the number of power fluctuations during standby can be reduced to reduce flicker.

Further, according to the present invention, flicker can be reduced by changing the lighting time of one turn of the heater according to the operation state of the image forming apparatus.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a structure of the image recording apparatus.

FIG. 3 is a flowchart showing an example of a control program stored in a ROM 6 of FIG.

FIG. 4 is a diagram illustrating an example of power fluctuation with respect to a main heater control signal and a sub heater control signal.

FIG. 5 is a cross-sectional view illustrating a structure of a fixing device.

FIG. 6 is an explanatory diagram for explaining heater driving according to a second embodiment.

FIG. 7 is a table showing a relationship between a temperature control temperature and a heater off time.

FIG. 8 is a flowchart illustrating an example of a flicker countermeasure control procedure according to the second embodiment.

FIG. 9 is a flowchart illustrating S205 of FIG. 8 in more detail.

FIG. 10 is a diagram showing an example of a power fluctuation with respect to a main heater control signal and a sub-heater control signal in a conventional example.

[Explanation of symbols]

 1 RAM 3 CPU 4 Heater control unit 5 Copy start key 11 Fixing main heater 12 Fixing sub-heater 13 Thermistor 14 Thermostat 15 Fixing roller 334 Fixing device

Claims (24)

[Claims] 1. A flicker suppressing device in an image forming apparatus, comprising: a fixing device having a heating element; a temperature detecting device for detecting a temperature of the fixing device; and a temperature detected by the temperature detecting device being a target temperature. Temperature control means for controlling the driving of the heating element by a pulse signal of a predetermined cycle, wherein the temperature control means includes a pulse during an image forming operation for reducing the number of power fluctuations in a standby state in which an image can be formed. A flicker suppressing device characterized in that the period of the pulse signal in the standby state is made longer than the period of the signal. 2. The image forming apparatus according to claim 1, wherein the fixing device has first and second heating elements, and the temperature control unit performs image formation on each of the first and second heating elements. A flicker suppressing device characterized in that the period of the pulse signal in the standby state is made longer than the period of the pulse signal during operation. 3. The method according to claim 2, wherein the temperature control unit is configured to perform the first heating in the standby state more than the on time of the first heating element and the on time of the second heating element during image formation. A flicker suppressing device, wherein the on-time of the element and the on-time of the second heating element are lengthened. 4. A flicker suppressing device in an image forming apparatus, comprising: a fixing device having a heating element; a temperature detecting means for detecting a temperature of the fixing device; and a memory storing control data indicating a time for turning on the heating element. And temperature control means for controlling driving of the heating element by a pulse signal of a predetermined cycle based on control data read from the memory so that the temperature detected by the temperature detection means becomes a target temperature, A flicker suppressing apparatus characterized in that the on-time of control data in the standby state is longer than the on-time of control data in the image forming operation in order to reduce the number of power fluctuations in the standby state. 5. The image forming apparatus according to claim 4, wherein the fixing device has first and second heating elements, and the temperature control unit performs an image forming operation on each of the first and second heating elements. A period of the pulse signal in the standby state longer than a period of the pulse signal at the time. 6. The method according to claim 5, wherein the temperature control unit is configured to perform the first heating in the standby mode more than the ON time of the first heating element and the ON time of the second heating element during image formation. A flicker suppressing device, wherein the on-time of the element and the on-time of the second heating element are lengthened. 7. A flicker suppressor in an image forming apparatus, comprising: a fixing device having a heating element; a temperature detecting unit for detecting a temperature of the fixing device; and a memory storing control data indicating a time for turning on the heating element. A first reading step of reading, from the memory, first control data representing an ON time in the standby state when the image forming apparatus enters a standby state capable of forming an image; A first driving step of driving the heating element by a pulse signal of a predetermined cycle based on the first control data read in the first reading step so as to reach a target temperature; and when an image forming operation is started. A second read step of reading second control data representing an ON time during image formation from the memory; Driving the heating element with a pulse signal of a predetermined cycle based on the second control data read in the second reading step so that the temperature detected by the temperature detection means becomes the first target temperature. With two drive steps, in order to reduce the number of power fluctuations in the standby state,
A method of suppressing flicker, wherein a period of a pulse signal during standby is longer than a period of a pulse signal during image formation. 8. The fixing device according to claim 7, wherein the fixing device has first and second heating elements, and in the first and second driving steps, reading is performed for each of the first and second heating elements. A method for suppressing flicker, wherein the first and second heating elements are driven by a pulse signal having a predetermined cycle based on the issued control data. 9. The image forming apparatus according to claim 8, wherein the on-time of the first heating element and the on-time of the second heating element in a standby state are the same as the on-time of the first heating element in an image forming operation. 2. A flicker suppressing method characterized in that the ON time of the heating element is longer than the ON time of the heating element. 10. A fixing device having a heating element, a temperature detecting means for detecting a temperature of the fixing device, and controlling the driving of the heating element so that the temperature detected by the temperature detecting means becomes a target temperature. A flicker suppression device in the image forming apparatus having a temperature control unit, wherein the temperature control unit sets the off time of the heating element in a standby state to reduce the number of power fluctuations in a standby state in which an image can be formed. A flicker suppressing device, wherein the fixed time is set to be longer than an off time of the heating element during operation. 11. The flicker suppressing device according to claim 10, wherein the temperature control means changes an off time of the heating element according to a target temperature during standby. 12. The device according to claim 10, further comprising a memory storing data indicating an off time of the heating element, wherein the temperature control unit controls driving of the heating element based on data read from the memory. A flicker suppression device characterized by the above-mentioned. 13. The fixing device according to claim 10, wherein the fixing device has first and second heating elements, and wherein the temperature control unit controls each of the first and second heating elements during standby. A flicker suppressor characterized by setting an off time independently. 14. The flicker suppression device according to claim 10, wherein the temperature control unit cancels the setting of an off-time in a standby time when an image forming operation is started. 15. A fixing device having a heating element, a temperature detecting means for detecting a temperature of the fixing device, and controlling the driving of the heating element so that the temperature detected by the temperature detecting means becomes a target temperature. A flicker suppressing method in the image forming apparatus having a temperature control unit, wherein a determining step of determining whether or not the image forming apparatus is in a standby state in which an image can be formed; A setting step of setting the off time of the heating element to a fixed time longer than the off time of the heating element during an image forming operation, so that the temperature detected by the temperature detection means becomes a target temperature during standby. Controlling the driving of the heating element based on the set off time. . 16. The flicker suppressing method according to claim 15, wherein in the setting step, an off time of the heating element is changed according to a target temperature during standby. 17. The image forming apparatus according to claim 15, further comprising: a memory storing data indicating an off time of the heating element, wherein the setting step sets the off time based on data read from the memory. A flicker suppression method characterized by: 18. The fixing device according to claim 15, wherein the fixing device has first and second heating elements, and in the setting step, each of the first and second heating elements is turned off during standby. A flicker suppression method characterized by independently setting the time. 19. The flicker suppressing method according to claim 15, further comprising a canceling step of canceling the off time set in the setting step when the image forming operation is started. 20. A fixing device having a heating element, a temperature detecting means for detecting a temperature of the fixing device, and controlling the driving of the heating element such that the temperature detected by the temperature detecting means becomes a target temperature. A flicker suppressing device in the image forming apparatus having a temperature control unit that performs the image forming operation. A flicker suppressing device, wherein the fixed time is set to be longer than an off time of the heating element during a forming operation. 21. The flicker suppression device according to claim 20, wherein the temperature control means changes an off time of the heating element according to a target temperature during standby. 22. The device according to claim 20, further comprising a memory storing data indicating an off time of the heating element, wherein the temperature control unit controls driving of the heating element based on data read from the memory. A flicker suppression device characterized by the above-mentioned. 23. The fixing device according to claim 20, wherein the fixing device has first and second heating elements, and wherein the temperature control unit controls each of the first and second heating elements during standby. A flicker suppressor characterized by setting an off time independently. 24. The flicker suppressing device according to claim 20, wherein the temperature control unit cancels the setting of the off time during standby when the image forming operation is started.