JP2833529B2 - Electrophotographic printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic printer, and more particularly to a technique for reducing power consumption and minimizing heat generation in a device in an electrophotographic printer. is there.

[0002]

2. Description of the Related Art FIG. 2 is a block circuit diagram showing a configuration of a conventional electrophotographic printer. In the electrophotographic printer, the toner adhered on the paper is fixed by heating the developed paper by the fixing roller 6. For this reason, the fixing roller 6 must be heated from the inside and always keep the surface at a constant temperature.

Usually, a main heater 10 incorporated in a fixing roller 6 is connected to a commercial power supply 1 via a main heater switch circuit 11. The temperature of the fixing roller 6 is detected by the temperature detecting means 7 and the temperature control circuit 8 performs an on / off operation of the main heater switch circuit 11 in accordance with the detected temperature, so that the temperature of the fixing roller 6 becomes constant. Is to be kept.

A DC stabilizing circuit 2 receives a commercial power supply 1 as an input, generates a stabilized DC power supply, and supplies the stabilized DC power to a load 3 including a motor and a lamp, and a control circuit 4 for controlling the entire electrophotographic printer. Supply.

[0005] The DC stabilizing circuit 2 is usually constituted by a power supply circuit of a switching power supply system. The DC stabilizing circuit 2 is designed to minimize power consumption in a steady load state, that is, in a state where a motor constituting the load 3 is rotating or a lamp is lit for miniaturization. .

FIG. 3 shows characteristics of self-consumption power versus output power in a switching power supply type DC stabilizing circuit. In FIG. 3, A indicates a light load state, and B indicates a steady load state. Is shown. As shown in FIG. 3, in a light load state in which the motors and lamps constituting the load 3 are stopped or turned off, the self-consumption power of the DC stabilization circuit 2 is:
As shown in FIG. 3, the power consumption is larger than the self-consumption in the steady load state.

The operation of the switching power supply type DC stabilizing circuit 2 becomes unstable when the load becomes extremely light as compared with the steady load state. In an electrophotographic printer, the power consumption of the load 3 composed of a motor and a lamp is considerably larger than the power consumption of the control circuit 4 which is a main load in a light load state. When the lamp is stopped or turned off, the DC stabilization circuit 2 enters an unstable operation state.

In order to prevent such an unstable operation of the DC stabilizing circuit 2 from occurring, a resistor 20 is connected to the output of the DC stabilizing circuit 2 and the DC stabilizing circuit 2 is connected.
In order to prevent the occurrence of an extremely light load state, a method is often used in which a load is always applied to a vehicle.

In Japanese Utility Model Laid-Open Publication No. 4-52213, a plurality of heaters connected to an AC power supply are incorporated in a heat fixing roller, and a switch element is provided between each heater and the AC power supply. By detecting the temperature of the roller and calculating the on / off combination of each switch element according to the temperature detection result, and controlling the on / off of each switch element according to the calculation result, the heat fixing roller It is described that the temperature is made to approach a target temperature.

[0010]

In the conventional electrophotographic printer as shown in FIG. 2, the total power consumption of the electrophotographic printer under a steady load state is the power consumed by the control circuit 4 and the rotational power. The sum of the power consumed by the load 3 including the motor in operation and the lamp being turned on, the self-power consumption of the DC stabilization circuit 2, the power consumption of the resistor 20, and the power consumption of the fixing roller 6 Become.

On the other hand, the total power consumption at the time of light load is smaller than the total power consumption at the time of the steady load state by a decrease in the power consumption of the load 3 due to the stop of the motor or the turning off of the lamp. 2 and the resistor 20
Increase by the amount of power consumption. The resistor 20 always consumes the same power as in the steady load state.

As described above, when the load is light, the heat generated by the resistor 20 for stabilizing the operation state of the DC stabilization circuit 2 and the heat generated by the increase in the self-consumption power of the DC stabilization circuit 2 during the light load are obtained. However, heat generation based on these causes causes an increase in heat generation in the device of the electrophotographic printer, and has adversely affected the environment.

In this case, as in the technique described in Japanese Utility Model Laid-Open No. 4-52213, even if the combination of a plurality of heaters is controlled to be connected to an AC power supply, the operation of the DC stabilization circuit is not possible. It is irrelevant and cannot be a means to solve the above problem.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to solve such a problem of the prior art. In an electrophotographic printer, a DC stabilizing circuit is provided even when a motor is stopped or a lamp is turned off during standby. The power consumption based on the load resistance used to increase the self-consumption power of the DC stabilization circuit in the light load state and stabilize the operation of the DC stabilization circuit at the light load state by preventing the light load state An object of the present invention is to provide an electrophotographic printer capable of preventing an increase in the number of images.

[0015]

In order to achieve the above object, an electrophotographic printer according to the present invention comprises the following means.

(1) a main heater housed in the fixing roller;
A temperature detecting means for detecting a temperature of the fixing roller, a temperature control circuit for turning on and off a main heater switch circuit provided between the main heater and the commercial power supply in accordance with a result of the temperature detection by the temperature detecting means; A DC stabilization circuit that converts AC power from a power supply into DC power and supplies it to a load such as a motor for driving a printing operation, and a control that operates with the DC power from the DC stabilization circuit and controls the operation of the motor and the like. And a circuit. Moreover, the main heater, and an auxiliary heater for heating the fixing roller, the auxiliary heater features an auxiliary heater switch circuit connected to the output of the DC stabilizing circuit, control circuit, the steady load state of the load as a reference
A function is provided to turn on the auxiliary heater switch circuit when the load is light .

Consumed by load 3 in steady load condition
The power is much larger than the power consumed by the control circuit 4.
DC stabilization circuit in the non-printing state of the printer
The load on the road 2 becomes extremely light. In such a situation,
The DC stabilization circuit 2 configured by the switching power supply method
Extreme stable operation may not be possible.
Load the DC stabilization circuit 2 so that it does not become lightly loaded.
Need to be applied. In a normal DC stabilization circuit, this
In such a case, a method using a resistor as a load
However, in the present invention, whether or not a resistor is connected
Instead, it is housed inside the fixing roller 6 together with the main heater 10.
The auxiliary heater 9 is connected to an auxiliary heater switch circuit.
5 to the output of the DC stabilization circuit 2. Therefore, according to the present invention, the power consumption of the resistor, which was conventionally required to stabilize the operation of the DC stabilization circuit under light load, is reduced by the power consumption of the auxiliary heater required for heating the fixing roller. Therefore, unnecessary power consumption can be reduced.

(2) In addition to the items specified in (1), the control circuit has a function of turning off the auxiliary heater switch circuit when driving control of a load such as a motor is started.

(3) In addition to the matter specified in (1), power supply from the DC stabilization circuit to the auxiliary heater causes the DC stabilization circuit to be in a steady load state.

Therefore, according to the present invention, it is possible to prevent an increase in the power consumption of the DC stabilizing circuit under a light load.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block circuit diagram showing one embodiment of the present invention.

The main heater 10 inside the fixing roller 6 is connected to the commercial power supply 1 via a main heater switch circuit 11. The temperature detecting means 7 detects the temperature of the fixing roller 6. The temperature control circuit 8 includes the main heater switch circuit 1.
By turning on and off the power supply 1, the amount of electric power supplied from the commercial power supply 1 to the fixing roller 6 is controlled, and the temperature of the fixing roller 6 detected by the temperature detecting means 7 is kept constant.

The DC stabilizing circuit 2 converts AC power from the commercial power supply 1 into DC power and supplies the DC power to the load 3 and the control circuit 4. The load 3 includes a motor for rotating the photoreceptor, a lamp serving as a light source for exposing the photoreceptor, and the like, and needs to supply DC power only while the electrophotographic printer is printing. The control circuit 4 includes a microprocessor, a memory, and the like, operates by DC power, and controls driving of a motor and a lamp.

When the DC stabilization circuit 2 converts AC power into DC power, the power required by itself is, as shown in FIG. 3, a steady load state in which the load 3 is consuming power.
That is, during printing by the printer, the standby state,
That is, in a non-printing state of the printer, it is generally larger when the motor constituting the load 3 is stopped or the lamp is turned off.

Further, since the power consumed by the load 3 in the steady load state is considerably larger than the power consumed by the control circuit 4, the load of the DC stabilization circuit 2 in the non-printing state of the printer is extremely light. Become. In such a state, the DC stabilization circuit 2 configured by the switching power supply method may not be able to maintain a stable operation state.
DC stabilization circuit 2 to prevent extreme light load condition
Need to be stressed.

In a normal DC stabilizing circuit, a method using a resistor as a load is performed as a countermeasure for such a case. In the present invention, instead of connecting a resistor,
The auxiliary heater 9 housed inside the fixing roller 6 together with the main heater 10 is connected to the output of the DC stabilization circuit 2 via the auxiliary heater switch circuit 5.

ON / OFF of the auxiliary heater switch circuit 5,
That is, the control circuit 4 controls whether or not the auxiliary heater 9 is used as a load of the DC stabilization circuit 2. The control circuit 4 is in charge of controlling the entire printer. The control circuit 4 turns on the auxiliary heater switch circuit 5 at the same time when the motors and lamps constituting the load 3 are stopped and turned off, and switches the auxiliary heater 9 on the DC stabilizing circuit 2. Connect as a load. At the same time as the rotation and lighting of the motor and lamp constituting the load 3, the auxiliary heater switch circuit 5 is turned off, and the auxiliary heater 9 is disconnected from the DC stabilization circuit 2.

By performing such control, the resistor (the resistor 2 shown in FIG. 2) conventionally required for stabilizing the operation of the DC stabilizing circuit 2 at the time of light load.
0) is unnecessary, and the unnecessary power consumption in the resistor is reduced.
The power consumption of the auxiliary heater 9 necessary for heating the fixing roller 6 can be replaced with power consumption.

Further, by increasing the power consumption for heating the fixing roller 6 which the auxiliary heater 9 bears, the load power amount of the DC stabilizing circuit 2 in the standby state can be increased. By doing so, the operation state of the DC stabilization circuit 2 can be constantly brought close to the steady load state, whereby the self-power consumption of the DC stabilization circuit 2 can be suppressed to a small level.

[0030]

As described above, according to the present invention,
The control circuit determines the load based on the steady load state of the load.
When the load is light, the auxiliary heater switch circuit is turned off.
The load of the DC stabilization circuit is always
The DC stabilization circuit at light load such as a motor.
The operation does not become unstable, and the power consumption of the resistor for stabilizing the operation of the DC stabilization circuit at light load, which was conventionally required, is reduced by the auxiliary heater required for heating the fixing roller. it is possible to replace the power consumption, excellent electrostatic unprecedented that Ru can reduce unnecessary power consumption
A child photo printer can be provided.

Further, the power consumption of the auxiliary heater is set to a steady load state when the DC stabilization circuit is in a standby state, thereby preventing an increase in power consumption of the DC stabilization circuit at a light load. Can be.

Therefore, according to the present invention, in the electrophotographic printer, power can be saved and heat generation in the device can be suppressed to a minimum.

[Brief description of the drawings]

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

FIG. 2 is a block circuit diagram showing a configuration of a conventional electrophotographic printer.

FIG. 3 is a diagram showing characteristics of self-consumption power versus output power in a switching power supply type DC stabilization circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Commercial power supply 2 DC stabilization circuit 3 Load 5 Switch circuit 6 Fixing roller 7 Temperature detecting means 8 Temperature control circuit 9 Auxiliary heater 10 Main heater 11 Switch circuit

Claims (3)

(57) [Claims] 1. A main heater housed in a fixing roller, a temperature detecting means for detecting a temperature of the fixing roller, and a temperature detecting means provided between the main heater and a commercial power supply according to a temperature detection result by the temperature detecting means. A temperature control circuit for turning on and off the main heater switch circuit, a DC stabilization circuit for converting AC power from the commercial power supply to DC power, and supplying the DC power to a load such as a motor for printing driving, An electrophotographic printer including a control circuit that operates by DC power from a conversion circuit to control the operation of the motor and the like, wherein the main heater includes an auxiliary heater that heats the fixing roller; An auxiliary heater switch circuit connected to the output of the conversion circuit, wherein the control circuit is configured based on a steady load state of the load.
An electrophotographic printer having a function of turning on the auxiliary heater switch circuit when the load is light . 2. The electrophotographic printer according to claim 1, wherein the control circuit has a function of turning off the auxiliary heater switch circuit when driving control of a load such as the motor is started. Features an electrophotographic printer. 3. The electrophotographic printer according to claim 1, wherein the power supply from the DC stabilization circuit to the auxiliary heater places the DC stabilization circuit in a steady load state. Printer.