JPH11339930A - Heating device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control current for each heater and to reduce current fluctuation in each half wave by independently controlling switching for current carrying and non current carrying of each heating element at each half wave of the current wave-form of the AC current. SOLUTION: A CPU 105a sets a unit pattern in five wavelengths of the commercial power supply used as the prescribed number of a group of half waves to divide the heating quantities of fixing heaters 119A, B into 10 steps for controlling the power. The CPU 105a calculates the current of the heaters 119A, B based on the temperature information detected by a temperature sensor 5 and turns the heater control signal on or off according to the unit pattern based on the zero crossing signal. When a current is carried to only either one of the heaters 119A, B, the current is carried to only the heater 119A in a half wave, then the current is carried to the heater 119B in the next half wave at staggered timing. The pattern of the first half wave is resumed from the 11th half wave, and the current control of the heaters 119A, B is repeated.

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 a heating device used for a fixing device.

[0002]

2. Description of the Related Art FIG. 38 is a sectional view showing an example of this type of image forming apparatus, for example, in the case of a laser beam printer.

[0003] In FIG. 38, 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 103.
Then, after being developed into a dot image and stored in the memory inside the video controller, it is returned to the engine unit 102 as a video signal.

[0004] Each element of the engine unit 102 is controlled by an engine controller 105, and the controller unit 10
Exchanging video signals with the engine controller 1
05. 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 a semiconductor laser 107 is controlled.

The laser beam 110 emitted from the semiconductor laser 107 is deflected by the polygon mirror 108 into scanning light in the longitudinal direction of the photosensitive drum 112, and is projected on the photosensitive drum 112 via the mirror 109. The photosensitive drum 112 rotates in the direction of the arrow, and the primary charger 11
ON / OFF of laser light after primary charging by 1
And an electrostatic latent image is formed on the surface of the photosensitive drum.

Then, colored charged particles (hereinafter, referred to as toner) are applied by a developing device 113 and a developed image is obtained. After that, a transfer charger 114 takes out the sheet one by one from a sheet cassette 120 by a sheet feeding roller 121. The visualized image is transferred to the recording material thus obtained. The transfer residual toner is wiped 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, a recording material having an unfixed toner image thereon is
After passing through the fixing device 116 to obtain a permanent fixed image, the recording material is discharged out of the apparatus as a final print in the direction of the arrow in the figure. It should be noted that the arrow in FIG.
4 shows a feed trajectory of a recording material taken out of the printer and conveyed.

The fixing device 116 has a heater (fixing heater) 119 as a heating element in the hollow fixing roller 117. When the heater 119 is energized, the fixing roller 1
17 is overheated, the output of a sensor (not shown) for detecting the surface temperature of the fixing roller 117 is input to a temperature controller (not shown), and the heater 119 is turned on / off.
Thus, a predetermined surface temperature is maintained.

The pressure roller 118 is pressed against the fixing roller 117 by a biasing means (not shown), and the unfixed toner on the recording material is transferred together with the recording material in a nip formed by the fixing roller 117 and the pressure roller 118. Heat and pressure are applied and permanent fixing is performed.

The engine controller includes a temperature sensor 5 mounted in contact with the fixing roller 117 of the fixing device 116.
The fuser controller 3 determines the temperature of the fixing device 116 based on the
To control the temperature of the fixing unit 116 by controlling the heater 119.

The heater 119 is composed of a heater (A) and a heater (B).
As shown in 37, control of energization / de-energization is performed every half cycle (half wave) of one wavelength of the commercial power supply, the control program calculates the electric power according to the value of the temperature sensor, and turns the triac ON / OFF accordingly. And control.

[0012]

However, when the currents flowing through the heaters (A) and (B) are made uniform, since the current is not controlled for each heater, the following problems have occurred.

[0013] Since the fluctuation of the current for each half-wave of the commercial power supply is large, it affects other devices connected to the same commercial power supply. When a lighting device is connected, flickering of the lighting device occurs, which causes discomfort to a person.

Since the wave numbers in the forward and reverse directions of the AC are not uniform, a DC component is generated with respect to the AC current, which causes an effect such that the transformer of the commercial power supply generates heat.

Since currents in the forward and reverse directions flowing through the heater (A) or the heater (B) do not become uniform, a current flows in a constant direction at a contact point of a connector connecting the control circuit and the heater, and a current flows to a contact portion. This may affect migration and the like, lowering durability.

When the control power is gradually increased or decreased, the currents flowing through the heaters (A) and (B) do not become uniform, so that the heat values of the heaters (A) and (B) become the same. Can not be controlled.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to control the current for each heater so as to reduce the fluctuation of the current for each half-wave and to have excellent reliability. A heating device and an image forming apparatus.

[0018]

In order to achieve the above object, a heating apparatus according to the present invention has a plurality of heating elements provided with an alternating current to be heated and has a current waveform of the alternating current. Switching of energization / de-energization of each heating element is controlled independently for each half-wave.

Therefore, it is possible to reduce the fluctuation of the current for each half-wave of the commercial power supply.

It is preferable that, of the plurality of heating elements, the first heating element and the second heating element are controlled by shifting the timing of switching from energization to non-energization and non-energization to energization.

As a result, it is possible to reduce the fluctuation of the current for each half-wave of the commercial power supply.

A plurality of unit patterns are provided with a predetermined half-wave number in accordance with the amount of power supplied to each heating element, in which a pattern for switching between energization and non-energization is provided. It is preferable to perform control to obtain the amount.

As a result, it is possible to reduce the fluctuation of the current for each half-wave of the commercial power supply.

The unit pattern is a half-wave number obtained by equally dividing the predetermined half-wave number by the number of heating elements, and sets a division pattern for switching between energization and non-energization for each heating element. It is preferable to replace each other and repeat the division pattern.

This makes it possible to reduce the fluctuation of the electric current for each half-wave of the commercial power supply.

The unit pattern is a half-wave number obtained by dividing the predetermined half-wave number equally into four, and a 4-division pattern for switching between energization and non-energization is set for each heating element, and the 4-division pattern is supplied to each heating element. It is preferable to supply a 4-division pattern in which the heating elements are exchanged with each other, further supply the 4-division pattern in the reverse direction from the end, and exchange the heating elements with each other and supply the 4-division pattern in the opposite direction.

This makes it possible to reduce the fluctuation of the electric current for each half-wave of the commercial power supply.

The predetermined half-wave number of the unit pattern of each heating element is provided by an even number, and the wave number of the positive half-wave in which the alternating current flows in the positive direction is equal to the wave number of the negative half-wave in which the alternating current flows in the reverse direction. Is preferred.

As a result, the consumed AC current does not include the DC component, and abnormal heat generation of the transformer of the power supply equipment can be prevented. In addition, it is possible to prevent migration that occurs at a contact portion of a connector that connects each heating element to the control circuit.

When the amount of electric power is changed, it is preferable to make the sum of the half-wave numbers of the respective heating elements equal.

Thus, even when the electric energy is changed,
Fluctuations in current for each half-wave of the commercial power supply can be reduced.

An image forming apparatus according to the present invention is characterized in that any one of the above-mentioned heating devices is provided in a fixing device for fixing an unfixed image on a recording material.

Therefore, the fluctuation of the current for each half-wave of the commercial power supply can be reduced, and the influence on the equipment connected to the same commercial power supply is small. In particular, flickering of connected lighting equipment can be reduced.

[0034]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the dimensions of the components described in this embodiment,
The material, shape, relative arrangement, and the like are not intended to limit the scope of the present invention only to them unless otherwise specified.

(First Embodiment) FIG. 1 is a block diagram showing an electrical configuration of an image forming apparatus.

Reference numeral 1 denotes a power switch for turning on the power of the image forming apparatus.
Used for N / OFF. Reference numeral 2 denotes a noise filter which reduces noise generated by the image forming apparatus so that the noise does not propagate to the AC line. Reference numeral 3 denotes a heater 1 as a heating element for performing heat fixing in the fuser control unit.
19 is detected by the temperature sensor 5 and the engine controller 105 is turned ON / OFF so as to keep the temperature constant.
Used for control.

FIG. 2 is a circuit block diagram of a fuser control unit embodying the present invention.
Is detected by the temperature sensor 5, and the current flowing to the heater is controlled by changing the timing of turning on the triac according to the temperature.

Two heaters 119 are connected in parallel, and are connected to a triac for controlling a current supplied to each of the heaters (A) and (B). Heater (A)
And the heater (B) have the same resistance value of 20Ω for easy explanation. The CPU 105a outputs heater control signals (A) and (B) as signals for controlling the triacs (A) and (B).

FIG. 3 shows the relationship between the voltage of the commercial power supply and the current waveform of the heater. Output a signal.

The amount of power to the heater is calculated based on the temperature information detected by the temperature sensor 5 by the program in the CPU. The program outputs heater control signals (A) and (B) based on the amount of electricity and the zero-cross signal. The triac of the fuser controller controls the heater to supply a current to the heater when the heater control signal is at a “high” level.

The heater control signal (A) controls the triac (A) to control the current supplied to the heater (A), and the heater control signal (B) controls the triac (B) to control the heater (B). Controls the current flow.
The current supplied to both heaters has a waveform obtained by adding the current supplied to the heater (A) and the current supplied to the heater (B), as shown in FIG.

Accordingly, the current supplied from the commercial power supply to the image forming apparatus has a waveform in which the current supplied to both heaters (A) and (B) and the current consumed in the low-voltage power supply unit are combined. For the sake of explanation, the current flowing through the heaters (A) and (B) will be described ignoring the current consumed by the low-voltage power supply unit.

The current supplied to the heater (A) and the heater (B) is turned on by turning on the control signal at the zero cross, and if the control signal is not turned on at the next zero cross, the half-wave current of the sine wave is increased. Flows.

The control signal is turned on at a certain timing from the leading edge on the front side of the zero-cross signal, and is turned off at a timing after a predetermined time until the gate current continues to flow for a time equal to or longer than the turn-on time of the triac. Once the current starts to flow, the triac continues to flow the current until the next zero-cross timing.

The program of the CPU 105a determines the current to be supplied to the heaters (A) and (B) based on the power consumption of the heaters to control the temperatures of the heaters (A) and (B).

FIGS. 4, 5, 6, and 7 are diagrams showing the relationship between the current waveform supplied to the heater and the power consumption of the heater. The control program divides the heating values of the heaters (A) and (B) into 10 steps and collects five wavelengths (10 half-waves) of the commercial power supply so that the power supplied to the heaters (A) and (B) can be controlled. Set the unit pattern as the predetermined half-wave number of
The temperatures of the heaters (A) and (B) are read to determine how much power is required for the heaters (A) and (B) so as to reach a desired temperature, and a control signal is turned ON / OFF according to the unit pattern. Control the current flowing through the heater.

FIG. 8 is a cross-sectional view illustrating the details of the fixing device. Heaters (A) and (B) are arranged in the fixing nip. The heaters (A) and (B) are formed on the same heater substrate, and the film and the heaters (A) and
A protective layer for protecting the heaters (A) and (B) is provided between (B). Further, a temperature sensor is provided in the fixing nip above the heater substrate to detect the temperature in the fixing nip.

With such a configuration, the amount of power supplied to the heater is controlled so that the heat generation in the fixing nip becomes constant.

In the unit pattern of the heater (A) and the heater (B) shown in FIGS.
When the first half-wave to the fourth half-wave are used, the same current is applied to both, and in the fifth half-wave, the current is applied only to the heater (A), and in the sixth half-wave, the heater (B) is used. And the seventh to tenth half-waves allow current to flow through both.

That is, when a current is supplied to only one of the heaters (A) and (B), the current is supplied to the heater (B) in a half-wave immediately after the current is supplied only to the heater (A). Stagger the timing. The amounts of heat generated by the heaters (A) and (B) are the same within one wavelength (two half waves).
In addition, the amount of change in the total current of the fourth half wave and the fifth half wave and the total current amount of the sixth half wave and the seventh half wave is only the amount of current flowing to one of the heaters, and is controlled so as to reduce the fluctuation of the current.

The control program returns to the first half-wave pattern after the eleventh half-wave in order to control the ten half-waves as a group of unit patterns.
The energization control of (B) is repeated.

As a result, the amount of electricity supplied to the heaters (A) and (B) becomes constant, and the amount of heat generated by each heater can be controlled to be the same.

The present invention can be applied to the case where the number of heaters is three or more. Also, even if the present invention is applied to the case where the resistance values of the heaters are different, the fluctuation of the current can be reduced and the lighting equipment can be connected. If so, flicker can be reduced.

(Second Embodiment) FIGS. 9, 10, 11,
FIG. 12 is a diagram illustrating a unit pattern of the heater according to the second embodiment.

Other configurations and operations are the same as those of the first embodiment, and therefore, the same components will be denoted by the same reference characters and description thereof will be omitted.

In the present embodiment, the heater (A) and the heater (B) are combined into five half-waves so that the amount of energization can be controlled in ten steps. Set the unit pattern for passing current.

A ten-step division pattern is set on the memory map of the control program from the first half wave to the fifth half wave.
If the division pattern from the first half wave to the fifth half wave is repeated as it is, the heat generation is biased to either the heater (A) or the heater (B) at an odd power ratio, so that the sixth half of the next five half waves. The division pattern from the wave to the tenth half wave is controlled so that the current flows by exchanging the division pattern of the heater (A) and the heater (B) of the previous five half waves (first to fifth half waves). I do.

Taking the power ratio of 90% as an example, in the first to fourth half waves, current flows through both the heater (A) and the heater (B), and in the fifth half wave, current flows only through the heater (A). Shed. Since the unit pattern of the heater (A) and the heater (B) is inverted from the sixth half wave, the current flows through both the heater (A) and the heater (B) from the sixth half wave to the ninth half wave, The tenth half wave is controlled so that current flows only through the heater (B). From the eleventh half wave, the control is repeatedly performed by returning from the first half wave to the second unit pattern.

To explain also when the current ratio is 70%, the first half wave allows current to flow only to the heater (A), the second half wave allows current to flow only to the heater (B), and the third and fourth half waves , The current flows through both the heaters (A) and (B), and the fifth half wave causes the current to flow only through the heater (A). The sixth half wave passes a current to the heater (B) opposite to the first half wave, the seventh half wave passes a current to the heater (A) opposite to the second half wave, and the eighth and ninth half waves Is the opposite of the third and fourth half-waves, both heaters (A),
An electric current is applied to (B), and an electric current is applied only to the heater (B) opposite to the fifth half wave in the tenth half wave.

The control is performed so that the memory of the control program can be reduced, and the deviation of the heat generation amount between the heater (A) and the heater (B) is reduced. Heater (A) and heater (B)
The unit pattern is set so that the variation of the total current for each half-wave is equal to or less than the current of one of the heaters.

Thus, the current flowing through the heaters (A) and (B) can be controlled to be the same in the unit pattern.

(Third Embodiment) FIGS. 13, 14, 1
5 and 16 are diagrams showing unit patterns of the heater according to the present embodiment. Similar to the second embodiment, the heater (A) is a unit pattern in which ten half-waves are grouped together and the previous five half-waves (first to fifth half-waves) are divided.
And the heater (B) is reversed, and the heater is energized for the next five half waves (sixth to tenth half waves).

Other structures and operations are the same as those of the second embodiment, and the description thereof is omitted.

In the second embodiment, when the power ratio is an odd number, the wave number of the heater (A) is larger than the wave number of the heater (B), but in this embodiment, the power amount is changed. At times, the relationship of the heater wave numbers shown below is set so that the sum of the half-wave numbers of each heater is equal.

[0065]

[Table 1] Thus, in the unit pattern with the power ratio of 90%, the heater (A) is set for one half wave more, and in the unit pattern with the power ratio of 70%, the heater (B) is set for one half wave, and the power ratio is set at 50%. In the unit pattern of, the heater (A) is set for one half wave more, the heater (B) is set for one half wave at a power ratio of 30%, and the heater (A) is set for one half wave at a power ratio of 10%. Set.

Considering the case where the energization amount is gradually increased from, for example, 20% to 60% in the heater temperature control, the energization amount of the heater (A) and the heater (B) is 2
At 0% it is equal, at 30% the heater (B)
Is increased by one half wave, equal at 40%, and 50%
At the time of (a), the heater (A) increases by one half wave, and at 60%, the heater (A) becomes equal. It is possible to control the heater (A) and the heater (B) so that the total amount of electricity is equal when all of them are added up.

(Fourth Embodiment) FIGS. 17 and 18 are diagrams showing a unit pattern of a heater in this embodiment.
A unit pattern of a current flowing through the heaters (A) and (B) as a group of five wavelengths (10 half waves) of the commercial frequency is shown.

Since other structures and operations are the same as those of the first embodiment, the same components are denoted by the same reference numerals and description thereof is omitted.

The current flowing through each heater is controlled such that the positive direction current is the positive direction and the negative direction current is the reverse direction, so that the positive direction and the reverse direction are the same in 10 half-waves. The following table summarizes the current flowing through each heater (A) and (B) for each direction.

[0070]

[Table 2] As described above, by implementing the present embodiment, the direction of the current flowing through the heaters (A) and (B) can be made to flow uniformly in the opposite direction to the forward direction to eliminate bias.
The consumed AC current does not include a DC component, so that abnormal heat generation of the transformer of the power supply equipment can be prevented. Also,
It is possible to prevent migration occurring at a contact portion of a connector that connects each heating element and the control circuit.

(Fifth Embodiment) FIGS. 19 to 32 are views showing this embodiment, and are diagrams showing unit patterns of current flowing through each heater.
(0 half wave) as a unit, and the unit patterns of the heaters (A) and (B) are shown for each power ratio.

The program reads the temperature with the temperature sensor, calculates the power ratio for supplying electricity to the heaters (A) and (B), and supplies the power to the heaters (A) and (B) as shown in the figure according to the power ratio. Apply current. The unit pattern of the present embodiment is a case where the power ratio is set in 20 steps in 5% steps. 19 to 26 show unit patterns from the first half wave to the thirteenth half wave, and FIGS. 26 to 32 show unit patterns from the eighteenth half wave to the thirty half wave.

The features of the present embodiment will be described by taking the case where the power ratio is 75% as an example. In the unit pattern with a power ratio of 75% in FIG. 20, the first half-wave energizes both the heaters (A) and (B),
The second half wave energizes only the heater (B). The third half wave energizes only the heater (A), and the fourth and fifth half waves energize both heaters.

The sixth and seventh half waves energize only the heater (A), and the eighth half wave energizes both. The ninth half wave energizes only the heater (B), and the tenth half wave energizes both.
The current on the upper side of the figure is the forward direction, and the current on the lower side is the reverse direction. Therefore, the odd half-wave is the current in the positive direction, and the even half-wave is
The current is in the opposite direction.

This is applied to the heater (A),
FIG. 34B is a table summarizing the wave numbers in the forward direction and the reverse direction. In the same table, the first half wave of 75% ~
When reading the value of the tenth half wave, the heater (A)
Four half waves, reverse direction = 4 half waves, heater (B) forward direction = 3 half waves, reverse direction = 4 half waves.

As a result, the heater (B) has one half wave less than the heater (A), and the forward direction has one half wave less than the reverse direction. Therefore, if the current ratio is maintained at 75% and the pattern from the first half wave to the tenth half wave is repeated without any change, the heater (A) generates heat from the heater (B), and the current in the forward direction becomes the current in the reverse direction. It will flow even more.

The heat generated by the heaters (A) and (B) becomes unbalanced and affects the image. If the direction of current flow is biased, the power supply equipment of the commercial power supply is affected.

In the present embodiment, in order to prevent such a situation, the first half wave to the tenth half wave are not repeated so that a problem does not occur. Add the unit pattern of. The first half wave to the tenth half wave are 4
Let it be a division pattern.

The eleventh-half to twenty-half-wave quarter-divided patterns correspond to the first half-wave to tenth half-wave quartered patterns by setting the energization timing of the heater (A) and the heater (B) respectively. Switch the power supply.

In the case where the energization ratio is 75% in FIG. 20 as an example, the eleventh half-wave is the first half-wave heaters (A) and (B).
Replace the pattern and turn on electricity. Since the first half wave energizes both heaters (A) and (B), the eleventh half wave also energizes both heaters. In the twelfth half-wave, since only the heater (B) is energized in the second half-wave, only the heater (A) is energized. In the thirteenth half wave, since only the heater (A) is energized in the third half wave, only the heater (B) is energized.

Although not shown, the fourteenth to seventeenth half waves are similarly energized by exchanging the heaters (A) and (B) for the fourth to seventh half waves. The eighteenth half-wave is the eighth half-wave, so that both heaters (A) and (B) are energized, so both are energized. In the nineteenth half wave, since only the heater (A) is energized in the ninth half wave, only the heater (B) is energized. In the second half wave, since both heaters are energized in the tenth half wave, both heaters are energized.

Therefore, when the wave numbers of the heaters (A) and (B) and the forward and reverse wave numbers of the eleventh to the twelfth half waves are totaled, the heater (A) forward direction = 3 ＝ wave,
The reverse direction = 4 half waves, the heater (B) forward direction = 4 half waves, and the reverse direction = 4 half waves.

The heater (A) is one more than the heater (B).
One half wave is reduced in the forward direction and one half wave is reduced in the forward direction. Therefore, if the first half wave to the second half wave are repeatedly energized, the energization amounts of the heater (A) and the heater (B) become the same. However, the amount of current flowing in the forward direction is smaller by two half waves than the amount of current flowing in the reverse direction.

The four-divided pattern from the twenty-first half wave to the thirty-half half wave is such that the four-divided pattern from the first half wave to the tenth half wave is turned on in reverse to the tenth half wave to energize. The 21st half wave is energized by the 10th half wave, and the 30th half wave is energized by the first half wave.

Referring to the example of the case of a 75% energization ratio in FIG. 27, the eleventh half-wave is energized in the same manner as the tenth half-wave, so that both heaters (A) and (B) are energized. Since the 22nd half-wave is the same as the ninth half-wave, only the heater (B) is energized.

Similarly, the 23rd half-wave is the same as the eighth half-wave and energizes both heaters (A) and (B). The 24th half-wave is the same as the seventh half-wave and (A) is energized only, the 25th half-wave is the same as the sixth half-wave, and only the heater (A) is energized. The 26th half-wave is the same as the fifth half-wave, and both heaters are energized. (A) and (B) are energized, the 27th half-wave is the same as the fourth half-wave and both are energized, and the 28th half-wave is the same as the third half-wave and the heater (A) Only energize the 29th half wave
As in the second half-wave, only the heater (B) is energized, and the thirtieth half-wave is the same as the first half-wave, and both heaters (A),
(B) is energized.

Therefore, when the wave numbers of the heaters (A) and (B) and the forward and reverse wave numbers of the 21st to 30th half waves are totaled, the heater (A) forward direction = 4 Half wave, reverse direction = 4 half wave, heater (B) forward direction = 4
Half wave, reverse direction = 3 half waves.

The heater (B) is one more than the heater (A).
One half wave is reduced in the reverse direction and one half wave is reduced in the reverse direction. Therefore, if current is repeatedly supplied from the first half wave to the thirtieth half wave, the heater (A) becomes one half wave larger than the heater (B), and the amount of electricity in the forward direction is one half wave larger than the amount of electricity in the reverse direction. Less.

The four-divided pattern from the 31st half-wave to the 40th half-wave is a pattern in which the four-divided pattern from the 11th half-wave to the 20th half-wave is applied in the reverse direction. The 31st half wave
Energize in the same way as the 20th half wave. Similarly, the 32nd to 40th half waves are energized in the same manner as the 19th to 11th half waves.

Accordingly, when the wave numbers of the heaters (A) and (B) and the forward and reverse wave numbers of the 31st to the 40th half waves are totaled, the heater (A) forward direction = Four half waves,
Reverse direction = 3 half waves, heater (B) forward direction = 4 half waves, reverse direction = 4 half waves.

The heater (A) is one more than the heater (B).
One half wave is reduced in the reverse direction and one half wave in the reverse direction. Therefore, if the first half wave to the forty half wave are repeatedly energized, the heater (A) and the heater (B) become the same, and the energization amount in the forward direction is the same as the energization amount in the reverse direction.

After the forty-first half wave, the current is repeatedly supplied from the first half wave.

FIG. 33 shows a table in which the wave numbers from the first half wave to the forty-half wave are tabulated for each power ratio.

In this embodiment, the heater (A),
Even when the amount of current supply in (B) is different and the amount of current supply in the forward and reverse directions of the AC power supply is different, the amount of current supply to the heater can be the same without setting a plurality of unit patterns.
The amount of the forward current and the amount of the reverse current can be the same.

[0095]

According to the heating apparatus of the present invention, a plurality of heaters are provided for heating by being supplied with an alternating current. By independently controlling the switching of non-energization, it is possible to reduce the fluctuation of the current for each half-wave of the commercial power supply.

[0096] Of the plurality of heating elements, the first heating element and the second heating element are controlled by shifting the timing of switching from energization to non-energization and from non-energization to half-wave of the commercial power supply. It is possible to reduce the fluctuation of the current for each.

A plurality of unit patterns in which a pattern for switching between energization and non-energization is provided at a predetermined half-wave number in accordance with the amount of power supplied to each heating element, and a predetermined power is obtained by repeating the unit patterns. By performing control to obtain the amount, each heating element is independently energized, and the fluctuation of the current for each half-wave of the commercial power supply can be reduced.

The unit pattern is a half-wave number obtained by equally dividing a predetermined half-wave number by the number of heating elements, and sets a division pattern for switching energization / de-energization for each heating element. , And by repeating the division pattern, it is possible to reduce the fluctuation of the current for each half-wave of the commercial power supply.

The unit pattern is a half-wave number obtained by equally dividing the predetermined half-wave number into four. A 4-division pattern for switching between energization and non-energization is set for each heating element, and the 4-division pattern is supplied to each heating element. By supplying a 4-division pattern in which each heating element is exchanged with each other, further supplying the 4-division pattern in reverse from the end, and exchanging each heating element with each other and supplying the 4-division pattern in reverse, Fluctuations in current for each half-wave of the power supply can be reduced.

The predetermined half-wave number of the unit pattern of each heating element is provided by an even number, and the wave number of the positive half-wave in which the AC current flows in the positive direction is equal to the wave number of the negative half-wave in the reverse direction in which the AC current flows. By doing so, the DC component is not included in the consumed AC current, and abnormal heat generation of the transformer of the power supply equipment can be prevented. In addition, it is possible to prevent migration that occurs at a contact portion of a connector that connects each heating element to the control circuit.

When the amount of power is changed, by making the sum of the half-wave numbers of the respective heating elements equal, it is possible to reduce the fluctuation of the current for each half-wave of the commercial power supply.

In the image forming apparatus of the present invention, since any one of the above-described heating devices is provided in the fixing device for fixing the unfixed image on the recording material, the fluctuation of the electric current for each half-wave of the commercial power supply can be reduced. And has little effect on devices connected to the same commercial power supply. In particular, flickering of connected lighting equipment can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an electrical configuration of an image forming apparatus.

FIG. 2 is a circuit block diagram illustrating a fuser control unit of the image forming apparatus.

FIG. 3 is a graph showing a relationship between a voltage of a commercial power supply and a current waveform of a heater.

FIG. 4 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 5 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 6 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 7 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 8 is a sectional view showing a fixing device according to the first embodiment.

FIG. 9 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 10 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 11 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 12 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 13 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 14 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 15 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 16 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 17 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 18 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 19 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 20 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 21 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 22 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 23 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 24 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 25 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 26 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 27 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 28 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 29 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 30 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 31 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 32 is a graph showing a relationship between a current waveform supplied to the heater and power consumption of the heater.

FIG. 33 is a table showing a total of half-waves of a current waveform supplied to a heater for each power consumption.

FIG. 34 is a graph showing a relationship between a current waveform supplied to a conventional heater and power consumption of the heater.

FIG. 35 is a graph showing a relationship between a current waveform supplied to a conventional heater and power consumption of the heater.

FIG. 36 is a graph showing a relationship between a current waveform supplied to a conventional heater and power consumption of the heater.

FIG. 37 is a graph showing a relationship between a current waveform supplied to a conventional heater and power consumption of the heater.

FIG. 38 is a schematic configuration diagram showing a conventional image forming apparatus.

[Explanation of symbols]

 Reference Signs List 1 power switch 2 noise filter 3 fuser control unit 5 temperature sensor 105 engine controller 105a CPU 119 fixing heater

Claims (8)

[Claims] 1. A heating device comprising: a plurality of heating elements to which an alternating current is supplied to heat the heating elements, wherein switching of energization / non-energization of each heating element is independently controlled for each half-wave of a current waveform of the alternating current. A heating device, characterized in that: 2. The method according to claim 1, wherein, of the plurality of heating elements, the first heating element and the second heating element are controlled by shifting the timing of switching from energization to non-energization and non-energization to energization. Item 2. The heating device according to Item 1. 3. A plurality of unit patterns in which a pattern for switching between energization and non-energization is provided at a predetermined half-wave number in accordance with the amount of power supplied to each heating element, and the unit pattern is repeated by repeating the unit pattern. The heating device according to claim 2, wherein control is performed to obtain the amount of electric power. 4. A unit pattern is a half-wave number obtained by equally dividing a predetermined half-wave number by the number of heating elements, and sets a division pattern for switching between energization and non-energization for each heating element. 4. The method according to claim 3, wherein the division pattern is repeated by replacing each body.
A heating device according to claim 1. 5. The unit pattern is a half-wave number obtained by equally dividing a predetermined half-wave number into four, and a four-division pattern for switching between energization and non-energization is set for each heating element, and the four-division pattern is supplied to each heating element. Then, a four-part pattern in which the heating elements are exchanged with each other is supplied, and further, the four-part pattern is supplied in reverse from the end to the front, and the four-part pattern is supplied in reverse with the respective heating elements exchanged. The heating device according to claim 3, characterized in that: 6. A predetermined half-wave number of a unit pattern of each heating element is provided as an even number, and a wave number of a positive half-wave in which an alternating current flows in a positive direction and a wave number of a negative half-wave in a reverse direction of the alternating current flow. The heating device according to claim 3, 4 or 5, characterized in that: 7. The method according to claim 3, wherein when the electric energy is changed, the sum of the half-wave numbers of the respective heating elements is made equal.
The heating device according to 4, 5, or 6. 8. An image forming apparatus comprising the heating device according to claim 1 in a fixing device for fixing an unfixed image on a recording material.