JP2009093961A - Heater control device and heater control method - Google Patents

Abstract

An inexpensive heater control device and heater control method that can obtain a desired amount of heat generated by a heater in a short time and increase power consumption are provided.
An electric power applied to a heater is increased for a predetermined time. For this purpose, the power supplied from the power sharing circuit is divided into two circuits, one of which is input to the active filter and the other is input to the control unit. The control unit outputs power from power-on to power-off, and controls the active filter to output power for a predetermined time from power-on. Furthermore, the heater control device and the heater control method of the present invention add the output power from the active filter and the output power from the control unit by the addition circuit, and apply them to the heater.
[Selection] Figure 1

Description

  The present invention relates to a heater control device and a heater control method for fixing an image forming material such as toner adhering to a recording medium to a recording medium in an image forming apparatus such as an electronic copying machine, a printer, and a fax machine.

  A conventional heater control apparatus applies input power boosted and rectified to a heater such as a halogen lamp at a constant voltage (for example, Patent Document 1).

  However, there is a problem that it takes time until the amount of heat generated by the heater, that is, the light quantity of the halogen lamp is suitable for fixing the image forming material.

In this regard, a method for increasing the power applied to the halogen lamp to obtain a desired light amount in a short time can be considered.
JP-A-5-216358

  However, there is a problem that increasing the amount of light increases power consumption and shortens the life of the halogen lamp.

  The present invention has been made in view of the above-described problems, and provides an inexpensive heater control device and heater control method that can obtain a desired heat generation amount of a heater in a short time and that has little increase in power consumption. The purpose is to do.

  In order to achieve this object, the heater control device and the heater control method of the present invention increase the power applied to the heater for a predetermined time. For this purpose, in the heater control apparatus and heater control method of the present invention, the power supplied from the power supply circuit is divided into two circuits, one of which is input to the active filter and the other is input to the control unit. The control unit outputs power from power-on to power-off, and controls the active filter to output power for a predetermined time from power-on. Furthermore, the heater control device and the heater control method of the present invention add the output power from the active filter and the output power from the control unit by the addition circuit, and apply them to the heater.

  According to the present invention, there is an effect that a desired heat generation amount of the heater can be obtained in a short time and an increase in power consumption can be reduced.

  Hereinafter, an embodiment of a heater control device and a heater control method according to the present invention will be described in detail with reference to the drawings. In addition, while attaching | subjecting the same code | symbol about the same location in each figure, the overlapping description is abbreviate | omitted.

<Details of Embodiment>
(First embodiment)
FIG. 1 is a schematic diagram showing the configuration of the heater control device of the present embodiment. As shown in FIG. 1, the heater control device of the present embodiment includes a boosting module 1 and a main module 2.

  The step-up module 1 steps up the power supplied from the AC power source 10 and starts the power supply when the power switch 11 is turned on, and filters the harmonics of the power supplied from the power supply circuit 12. And an active filter 13 that converts the pulse wave into a substantially sine wave and outputs electric power.

  The main module 2 is supplied with power from the power supply circuit 12, is turned on when the power switch 11 is turned on, outputs power from when the power is turned on to when the power is turned off, and has a pulse width of a voltage for a predetermined time after the power is turned on. The control unit 14 that modulates and controls the active filter 13 to output power for a predetermined time after power-on, the output power from the active filter 13, and the output power from the control unit 14 are added to the heater 16. And an adding circuit 15 for outputting.

  Pulse width modulation is performed by combining circuits such as a so-called chopper circuit, and smoothes the rectified waveform to suppress flicker.

  FIG. 2 is an example of a circuit configuration of the heater control device of this embodiment. FIG. 3 is a timing chart of the heater control device of this embodiment. 3A to 3H correspond to FIGS. 2A to 2H. In FIG. 2, the part other than the active filter 13 of the boost module 1 corresponds to the power supply circuit 12, and the part other than the addition circuit 15 corresponds to the control unit 14.

  The boost module 1 can be appropriately configured by combining known circuits such as a so-called boost circuit. The active filter 13 can use, for example, PFC (Power-factor correction), but is not limited thereto. The active filter 13 of the present embodiment includes a full-wave rectifier circuit, a switching element Q2 (e) connected to the full-wave rectifier circuit, and an integrated circuit IC1. The control unit 14 controls the operation of the active filter 13 by a control signal.

  The AC power source (a) is connected to the relays RL1 and RL2 (b) through a filter, and is further connected to the active filter 13 through an inrush current prevention circuit (c). The active filter 13 is connected to the heater 16 via the adding circuit 15.

  The AC power source (a) is connected to the relays RL3 and RL4 (g) through a filter, and is connected to the control unit 14 through a full-wave rectifier circuit. The control unit 14 includes an integrated circuit IC2 and a switching element Q1 (d). Further, the control unit 14 is connected to the heater 16 (h) via the addition circuit 15.

  The adder circuit 15 is configured by connecting the power output pattern from the active filter 13 and the power output pattern from the control unit 14.

  When the switch 1 shown in FIG. 2 is turned on, current flows through the coil RL3c of the relay RL3 and the coil RL4c of the relay RL4, the relay RL3 and the relay RL4 are closed, and power is supplied to the control unit 14.

  When power is supplied to the active filter 13, the control unit 14 controls the current to flow through the coil RL1c of the relay RL1 and the coil RL2c of the relay RL2. When current flows through these coils, the relays RL1 and RL2 are closed, and power is supplied to the active filter 13. Note that the time during which current flows through the active filter 13 may be controlled by a timer, and the controller 14 may be configured to control this timer.

  Next, description will be made with reference to FIG. When the power is turned on and the AC input (a) is started at a soft start (t0 to t1) that suppresses the voltage increase rate and reduces flicker at time t0, the relays RL1 and RL2 (b) in FIG. The relays RL5 (c) are turned on until a predetermined time t2. The switching element Q1 (d) in FIG. 2 is turned on from power-on t0 to power-off t6. On the other hand, the switching element Q2 (e) in FIG. 2 is turned on from the power-on time t0 to a predetermined time t2.

  While the switching element Q2 (e) is ON (t0 to t2), the active filter 13 is ON. The relay RL3 and the relay RL4 (g) in FIG. 2 are turned on in synchronization with the timing t2 when the switching element Q2 (e) is turned off.

  For this reason, the voltage applied to the halogen lamp as the heater 16 (h) is the output voltage 110V of the active filter 13 and the output voltage of the control unit 14 while the active filter 13 is ON (t0 to t2). It becomes 190V which is the voltage which added 80V. The time (t0 to t2) during which the added voltage is applied to the heater 16 is, for example, about 0.5 to 1.0 seconds.

  When the active filter 13 is turned off, the voltage applied to the heater 16 (h) is only the output voltage from the control unit 14 and is 80V.

  When the power is turned off and the AC input (a) is turned off at time t7, the switching element Q1 (d), relay RL3, relay RL4 (g) is turned off, and the voltage applied to the heater 16 (h) is 0V. Become.

  FIG. 4 is a graph showing the time until the target light amount of the heater 16 is obtained. The vertical axis represents the light amount and current, and the horizontal axis represents time. A curve 23 indicates a current flowing through the active filter 13. A curve 21 is a curve showing the relationship between the amount of light of the heater 16 and time by the heater control device of the present embodiment. When a current flows through the active filter 13 at time t11 as shown by the curve 23, the light quantity of the heater 16 increases rapidly as shown by the curve 21, and reaches the target light quantity at time t12. That is, according to the heater control apparatus of the present embodiment, the heater 16 reaches the target light intensity at 520 ms indicated from t11 to t12 when the power is turned on.

  A curve 22 is a curve showing the relationship between the amount of light of the heater 16 and time by the conventional heater control device. As shown by the curve 22, according to the conventional heater control device, the heater 16 takes 1720 ms from t11 when the power is turned on until t13 when the target light amount is reached. The target light amount is reached in less than a minute.

  As described above, according to the heater control device and the heater control method of the present embodiment, the output power of the active filter 13 and the power are output from the time of power-on to the time of power-off, and the active filter 13 is turned on from the time of power-on. The adder circuit 15 adds the output power of the control unit 14 that controls to output power for a predetermined time and supplies the sum to the heater 16. For this reason, there is an effect that a desired heat generation amount of the heater 16 can be obtained in a short time and an increase in power consumption can be reduced.

(Second Embodiment)
The heater control device of the present embodiment is characterized in that the control unit 14 of the heater control device of the first embodiment further changes the time during which the active filter 13 outputs power in proportion to the power-off time.

  In FIG. 3, T OFF represents the time during which the power is turned off. In proportion to the length of T OFF, the control unit 14 changes Th, which is the time during which the active filter 13 outputs power.

  The control unit 14 counts time using the internal clock of the control unit 14. The control unit 14 starts counting time when the power is turned off, and ends counting time when the power is turned on again. The control unit 14 calculates a time proportional to the length of the counted time, starts counting time when the active filter 13 starts outputting power, and when the calculated time is reached, the active filter 13 Terminate output.

  As described above, in the present embodiment, the control unit 14 changes the time during which the active filter 13 outputs power in proportion to the power-off time. For this reason, there is an effect that power consumption can be reduced.

(Third embodiment)
The heater control device of the present embodiment is characterized in that, in the heater control device of the first embodiment, the control unit 14 further performs dimming control. As shown in FIG. 2, the dimming circuit Dim (f) can be provided inside the integrated circuit IC2.

  As shown in FIG. 3, after the power supply from the active filter 13 is stopped at time t <b> 2, the control unit 14 turns on the dimming circuit Dim (f) at time t <b> 4 that is a predetermined time later, and turns on the heater 16. Reduce the output power. As shown in FIG. 3, for example, when the dimming circuit Dim (f) is ON (t4 to t6), the control unit 14 decreases the voltage applied to the halogen lamp as the heater 16 from 80V to 50V.

  As described above, in the heater control device of the present embodiment, the control unit 14 reduces the power output after a predetermined time after the power supply from the active filter 13 is stopped. For this reason, there is an effect that power consumption can be further reduced.

(Fourth embodiment)
The heater control device according to the present embodiment is the same as that of the heater control device according to the third embodiment, except that the power supply from the active filter 13 is stopped from the time t4 to t5 during which the control unit 14 further shows in FIG. When the power output after a predetermined time is reduced, the speed at which the power is reduced is slower than when the control is not performed.

  For example, the control unit 14 measures the time with the internal clock, and controls the power to decrease at a constant rate every fixed time, so that the speed at which the power is decreased is slower than when the control is not performed.

  Even if the controller 14 controls the dimming circuit Dim to reduce the power reduction rate so that it is slower than when the control is not performed, the dimming circuit Dim may reduce the power reduction rate. The control unit 14 may be configured to slow down the power reduction rate.

  In addition, control is performed when power is supplied from the other part indicated by Ts in FIG. 3, that is, when power is supplied from the active filter 13 and power is not supplied from the active filter 13, and when the dimming circuit Dim is turned from ON to OFF. Even when the power supplied by the unit 14 is increased, the rate of change of the power output by the control unit 14 can be controlled to be smaller than when the control is not performed.

  As described above, in the heater control device of the present embodiment, when the control unit 14 decreases the power output after a predetermined time after the power supply from the active filter 13 is stopped, the speed at which the power is decreased is Slower than when not controlling. For this reason, there is an effect that generation of flicker can be further suppressed.

<Possibility in the embodiment of the present invention>
Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

It is a schematic diagram which shows the structure of the heater control apparatus of this invention. It is an example of the circuit structure of the heater control apparatus of this invention. It is a timing chart of the heater control device of the present invention. It is the graph which showed time until it obtains the target light quantity of a heater.

Explanation of symbols

1: Boost module,
2: Main module
10: AC power supply,
11: Power switch
12: power supply circuit,
13: Active filter
14: control unit,
15: Adder circuit,
16: Heater.

Claims (8)

A power supply circuit that boosts and supplies power; and
An active filter for filtering harmonics of power supplied from the power supply circuit;
A control unit that receives power from the power supply circuit, outputs power from power-on to power-off, and controls the active filter to output power for a predetermined time from power-on;
An adding circuit that adds the output power from the active filter and the output power from the control unit and outputs the sum to the heater;
A heater control device comprising: A power supply circuit that boosts and supplies power; and
An active filter for filtering harmonics of power supplied from the power supply circuit;
Receives power from the power supply circuit, outputs power from power-on to power-off, modulates voltage for a predetermined time from power-on, and outputs power for a predetermined time from power-on to the active filter A control unit for controlling to
An adding circuit that adds the output power from the active filter and the output power from the control unit and outputs the sum to the heater;
A heater control device comprising:   The heater control device according to claim 1, wherein the control unit changes a time for which the active filter outputs power in proportion to a power-off time.   4. The heater control device according to claim 1, wherein the control unit reduces power output after a predetermined time after power supply from the active filter is stopped. 5.   The control unit, when reducing the power output after a predetermined time after the power supply from the active filter is stopped, makes the power reduction rate slower than when the control is not performed. Item 5. The heater control device according to Item 4. In the heater control device that controls power supply to the heater,
Output power of an active filter that filters harmonics of power supplied from a power supply circuit that boosts and supplies power; and
Receives power from the power supply circuit, outputs power from power-on to power-off, and adds the output power of the control unit that controls the active filter to output power for a predetermined time from power-on Add in the circuit and supply to the heater,
The heater control method characterized by the above-mentioned.   The heater control method according to claim 6, wherein the control unit reduces the power output after a predetermined time after the power supply from the active filter is stopped.   The control unit, when reducing the power output after a predetermined time after the power supply from the active filter is stopped, makes the power reduction rate slower than when the control is not performed. Item 8. The heater control method according to Item 7.

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