JPH10186912A - Flicker reducing device and image recorder provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a change in current sudden in a load and to reduce flickering, in a copying machine, etc., with the load requiring a high current such as a heater, an illuminating lamp, etc. SOLUTION: A current limiter circuit 111 constituted of a series circuit consisting of a switch 112 and a resistance element part 113 is connected to a switch 110 connected to a heater 102 in series, in parallel. Further, a current limiter circuit 131 constituted of a series circuit consisting of a switch 132 and a resistance element part 133 is connected to a switch 130 connected to a lamp 121 in series, in parallel. Then, each switch is controlled by a heater control part 114 and a lamp control part 134 and at the time of supplying power to the heater 102 and the lamp 121, the switches 112 and 132 of the respective current limiter circuits 111 and 131 are turned on and then, the switches 110 and 130 are turned on after a specified time lapses. At the time of turning off the power, the switches 110 and 130 are tuned off and then, the switches 112 and 132 are turned off after the specified time lapses.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flicker reducing apparatus for reducing flicker caused by a load such as a heater or a lamp requiring a large current, and an image recording apparatus provided with the same.

[0002]

2. Description of the Related Art Conventionally, for example, in a fixing control operation in a heat fixing control device having a heater, the temperature is obtained from a temperature detecting means provided adjacent to a fixing roller or a fixing film (or a belt) in which a heater is stored. Based on the temperature information, if the temperature is lower than the predetermined temperature, the heating operation is started (turns on the heater). If it is confirmed that the temperature has reached the predetermined temperature, the heating operation is stopped (the heater is turned off) and the temperature is lowered to the predetermined temperature or lower. Then, the power supply operation is restarted (the heater is turned on), and the temperature is controlled to be maintained at the predetermined temperature.

In a lamp control operation of an image reading apparatus having a lamp, the lamp is turned on at the start of image reading and is turned off at the end of reading.

[0004]

However, in the above-described conventional operation control, a sharp current change occurs when the heater or the lamp is turned on and when the heater or the lamp is turned off. There has been a problem that a power supply fluctuation occurs due to the impedance and a sudden current change, and flicker occurs in an external lighting device or the like due to the power supply fluctuation. In particular, the larger the wattage of the heater or lamp, the greater the change in current and the more noticeable the flicker.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides a flicker reducing apparatus capable of suppressing a sudden change in current and reducing flicker, and an image recording apparatus having the same. It is intended to be.

[0006]

The flicker reducing apparatus according to the present invention is configured as follows.

(1) a first switch connected in series with a load, a suppression circuit including a series circuit of a second switch and an impedance element connected in parallel with the first switch; A control unit for controlling a switch and a second switch, wherein the control unit is configured to control the first switch a predetermined time after the second switch is turned on when power is supplied to the load.
Is controlled to be turned on, and the second switch is controlled to be turned off a predetermined time after the first switch is turned off when the power supply to the load is stopped.

(2) In the flicker reduction apparatus of (1), the impedance element is a resistance element.

(3) In the flicker reduction apparatus of (1) or (2), the load is a heater.

(4) In the flicker reducing apparatus of (1) or (2), the load is a lamp.

The image recording apparatus according to the present invention is configured as follows.

(5) a first switch connected in series with the load, a second switch connected in parallel with the first switch, and a suppression circuit including a series circuit of an impedance element; The first switch is controlled to be turned on a predetermined time after the second switch is turned on when power is supplied, and the power is turned off when the power to the load is stopped. Second
And a control unit for controlling the switch to be turned off.

(6) In the image recording apparatus of (5), the impedance element is a resistance element.

(7) In the image recording apparatus of the above (5) or (6), the load is a halogen heater for heat fixing.

(8) In the image recording apparatus of (5) or (6), the load is a ceramic heater for heat fixing.

(9) In the image recording apparatus of (5) or (6), the load is a lamp for reading an image.

(10) In the image recording apparatus of (5) or (6), the load is a heater for heat fixing and a lamp for reading an image.

(11) In the image recording apparatus according to (7), (8) or (10), the control unit controls energization of the heater based on the detected temperature of the heater detected by the temperature detecting means. I made it.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIG. 1 is a view showing the structure of a first embodiment of the present invention, and shows the structure of a copying machine provided with a heat fixing device having a heater as an image recording device and an image reading device having a lamp. Is shown.

In FIG. 1, reference numeral 1 denotes an external AC power supply, 2 denotes a power line impedance circuit, and 3a and 3b denote AC outlets. Power is supplied to the present apparatus from the AC outlet 3a, and from the AC outlet 3b to the external lighting device 4. Power is supplied.

Reference numeral 100 denotes a copying machine having a flicker reduction circuit; 101, a heater section having a heater (load) 102 made of ceramic, halogen, or the like; 103, a heater 10;
Heater roller of a heat fixing device in which 2 is disposed, 1
Reference numeral 04 denotes a pressure roller disposed to face the heater roller 103, and reference numeral 105 denotes a temperature detecting unit that detects a surface temperature of the heater roller 103.

Reference numeral 110 denotes a first switch for turning on or off a normal heater current, which is connected in series with the heater 102. 111 is a current limiting circuit (suppression circuit) connected in parallel with the first switch,
12 and a series circuit of a resistance element section (impedance element section) 113. Reference numeral 114 denotes a heater control unit that controls on / off of the first switch 110 and the second switch 112 based on the temperature information obtained from the temperature detection unit 105.

Reference numeral 120 denotes an image reading unit having a lamp (load) 121; 122, a document table on which a document 123 is placed;
Reference numeral 124 denotes the light of the lamp 121,
3 is a document light receiving unit that captures the reflected light when the light is applied to the document 3.

Reference numeral 130 denotes a third switch (first switch) for turning on or off a normal lamp current, which is connected in series with the lamp 121. 131 is a current limiting circuit (suppression circuit) connected in parallel with the third switch.
It comprises a series circuit of a fourth switch (second switch) 132 and a resistance element section (impedance element section) 133. Reference numeral 134 denotes a lamp control unit that controls on / off of the third switch 130 and the fourth switch 132 based on image capture start information given from an operation panel unit (not shown).

In the above configuration, AC power is supplied from the external AC power supply 1 to the copying machine 100 from the AC outlet 3a via the power supply line impedance circuit 2, and AC power is supplied from the AC outlet 3b to the external lighting device 4. .

When the power switch of the copier 100 is turned on, the heater unit 101 first performs a heating operation in order to shift to a copying operation enabled state. At the time of this heating operation, first, the temperature detection unit 1 inside the heater unit 101 is used.
In step 05, the surface temperature of the heater roller 104 having the heater 102 therein is detected.

If the detected temperature is equal to or lower than the copy operable temperature, first, the resistance element portion 113 of the current limiting circuit 111
And a second switch 1 for supplying a current to the heater 102.
12 is turned on. Then, after a predetermined time, the first switch 110 is turned on, so that a regular heater current flows through the heater 101.

At this time, when the second switch 112 is turned on, a heater current flows through the resistance element portion 113, so that the heater current first flowing through the heater 101 is equal to the impedance of the resistance element portion 113 and the second switch 112. Only limited. When the first switch 110 is turned on, the heater 101 is warmed up, so that the rush current of the heater 101 is reduced.

When the temperature detected by the temperature detecting means 105 becomes higher than the copy operable temperature, the first switch 110 is first turned off from the state where both the first switch 110 and the second switch 112 are turned on. The heater 10 is connected via the resistance element 113 of the current limiting circuit 111.
By turning off the second switch 112 a predetermined time after turning on the second switch 112 for flowing the current through the heater 2, the current flowing through the heater 101 is shut off.

At this time, even if the first switch 110 is turned off, a heater current flows through the resistance element portion 113. That is, a current limited by the impedance of the resistance element portion 113 and the second switch 112 flows through the heater 101. Then, when the second switch 112 is turned off, the current of the heater 101 is cut off from the limited state, so that the change in the heater current is reduced.

The first switch 110 and the second switch 110
Switch 112 is turned on and off by the temperature detecting means 105.
Is controlled by the heater control unit 114 based on the temperature information from the controller.

When the heater 101 of the copying machine 110 reaches a predetermined temperature, the copying machine is ready for copying. In this state, when the copy button on the operation panel (not shown) is pressed, the document 12 on the platen 122 of the image reading unit 120 is pressed.
3 is irradiated with light from a lamp 121, and the resulting reflected light from a document 123 is read by a document light receiving unit 124.

The read image information of the document 123 is processed by an image processing unit (not shown) and then charged, exposed, developed, and transferred by a recording unit (not shown) of an electrophotographic process system. After each process, it is transferred to a transfer material (recording paper). The toner is thermally fixed on the transfer material by the heater roller 103 and the pressure roller 104, which are maintained at the above-described copying operable temperature by the heater unit 101, and are discharged outside the copying machine 100.

The lamp 121 of the image reading unit 120
, The current limiting circuit 131
The fourth switch 132 is turned on in order to supply a current to the resistance element portion 133 and the lamp 121. Then, by turning on the third switch 130 after a predetermined time,
A normal lamp current is supplied to the lamp 121.

At this time, when the fourth switch 132 is turned on, a lamp current flows through the resistance element portion 133. The current flowing through the lamp 121 is equal to the resistance element portion 133.
And the impedance of the fourth switch 132. When the third switch 130 is turned on, the lamp 121 is warmed up, so that the rush current of the lamp 121 is reduced.

When the image reading is completed, the third
First, the third switch 130 is turned off from the state where both the switch 130 and the fourth switch 132 are turned on, and the fourth switch for flowing a current to the lamp 121 via the resistance element portion 133 of the current limiting circuit 131. By turning off the fourth switch 132 a predetermined time after the switch 132 is turned on, the lamp current of the lamp 121 is cut off.

At this time, when the third switch 130 is turned off, a lamp current flows through the resistance element portion 133.
And the impedance of the fourth switch 132. Further, when the fourth switch 132 is turned off, the current flowing through the lamp 121 is cut off from the limited state, so that the change in the lamp current is reduced.

Note that the third switch 130 and the fourth
Of the switch 132 is controlled by the lamp control unit 134 based on the copy start information.

Here, the copying machine 100 has an external AC power source 1
Power is supplied from the AC outlet 3a via the power supply line impedance circuit 2, and similarly, power is supplied to the external lighting device 4 from the AC outlet 3b via the power supply line impedance circuit 2 from the external AC power supply 1. I have. That is, the power line impedance circuit 2
Are shared by the two devices, so if a sudden current change occurs in one of the devices, the AC outlet 3a and the AC outlet 3b are affected by the power line impedance circuit 2.
The power supply voltage fluctuation occurs in the portion.

In the case of the copying machine 100, there are mainly a heater 102 and a lamp 121 as loads having a large wattage, and when these are turned on and turned off, a sudden change in current is caused. As a result, the power supply voltage fluctuates in the AC outlet 3a and the AC outlet 3b. In this embodiment,
This rapid current change is suppressed by the control of the current limiting unit 111 and the heater control unit 114 and by the current limiting unit 131 and the lamp control unit 134 to reduce flicker.

FIG. 2 shows the current limiting section 111 in this embodiment.
5 shows the effect of a change in current when the heater control unit 114 is used and a change in power supply voltage at the AC outlet 3a and the AC outlet 3b.

FIG. 3 shows the current limiting section 1 in this embodiment.
3 shows the effect of a current change and a power supply voltage change at the AC outlet 3a and the AC outlet 3b when the lamp control unit 31 and the lamp control unit 134 are used.

FIG. 4 is a diagram showing a current change in the case where the conventional current limiting section 111 and the heater control section 114 are not provided, and the influence of a power supply voltage change in the AC outlets 3a and 3b. FIG. 7 is a diagram illustrating a current change when there is no current limiting unit 131 and a lamp control unit 134 and an influence of a power supply voltage change between the AC outlet 3a and the AC outlet 3b.

By shifting the timing of turning on and off the heater 102 and the lamp 121, the copying machine 1
It is also possible to control so as to reduce the current change in the whole 00, and to give the heater control unit 114 and the lamp control unit 134 a priority order. (Second Embodiment) In the above-described embodiment, the number of heaters 102 is one. However, in the case of having two or more heaters, a heater having the same configuration and control as the heater 101 is provided. The function and effect of can be obtained.

Also, when there are a plurality of heater units, the heater control unit 114, the lamp control unit 134, and the other heater control units are given a priority order to turn on and off the heater 102, the lamp 121, and the other heaters. By shifting the timing, it is also possible to control so as to reduce the current change in the entire copying machine 100.

(Other Embodiments) Further, in the above-described embodiment, the copying machine has the image reading section 120. However, the same function and effect can be obtained in a printer without the image reading section 120.

[0047]

As described above, according to the present invention,
When supplying power to the load, first turn on the current suppression circuit in parallel with the load for a predetermined time, and then turn on the switch for flowing the normal load current. Since the current suppressing circuit is turned off a predetermined time after the switch for flowing the normal load current is turned off, an abrupt current change can be suppressed, and there is an effect that power supply fluctuation is small and flicker can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a control example of a heater unit according to the embodiment.

FIG. 3 is an explanatory diagram showing a control example of the lamp according to the embodiment;

FIG. 4 is an explanatory diagram showing a control example of a conventional heater unit.

FIG. 5 is an explanatory diagram showing a control example of a conventional lamp unit.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 external AC power supply 2 power supply line impedance circuit 4 external lighting device 100 copying machine 101 heater section 102 heater (load) 105 temperature detecting means 110 first switch 111 current limiting circuit (suppression circuit) 112 second switch 113 resistance element section (Impedance element unit) 114 Heater control unit 120 Image reading unit 121 Lamp (load) 130 Third switch (first switch) 131 Current limiting circuit (suppression circuit) 132 Fourth switch (second switch) 133 Resistance Element section (impedance element section) 134 Lamp control section

Claims (11)

[Claims] A first switch connected in series with a load; a suppression circuit including a series circuit of a second switch and an impedance element connected in parallel with the first switch; and the first switch. And a control unit that controls the second switch, and the control unit controls the first switch to be turned on a predetermined time after the second switch is turned on when power is supplied to the load. And a flicker reducing device that controls the second switch to be turned off a predetermined time after the first switch is turned off when the power supply to the load is stopped. 2. The flicker reducing apparatus according to claim 1, wherein the impedance element is a resistance element. 3. The flicker reducing apparatus according to claim 1, wherein the load is a heater. 4. The flicker reducing apparatus according to claim 1, wherein the load is a lamp. 5. A suppression circuit comprising a first switch connected in series with a load, a second switch connected in parallel with the first switch, and a series circuit of an impedance element, and a power supply to the load. The first switch is controlled to be turned on a predetermined time after the second switch is turned on at the time of supply, and the first switch is turned off a predetermined time after the first switch is turned off when the power to the load is stopped. An image recording apparatus, comprising: a flicker reduction device having a control unit for controlling a switch of the second switch to be turned off. 6. The image recording apparatus according to claim 5, wherein the impedance element is a resistance element. 7. The image recording apparatus according to claim 5, wherein the load is a halogen heater for heat fixing. 8. The image recording apparatus according to claim 5, wherein the load is a ceramic heater for heat fixing. 9. The image recording apparatus according to claim 5, wherein the load is a lamp for reading an image. 10. The image recording apparatus according to claim 5, wherein the loads are a heater for heat fixing and a lamp for reading an image. 11. The heater according to claim 7, wherein the controller controls energization of the heater based on the temperature of the heater detected by the temperature detector.
The image forming apparatus as described in the above.