JP2001188458A - Control method and device for fan for electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that a heater is used for the purpose of thermal fixing in an electrophotographic device using an ordinal paper, but when this heat stays on the inside of the device, many problems are generated, and as a result, a fan for cooling the inside of the device is used, but there is dissatisfac tion in energy conservation and noise prevention in the conventional method and product. SOLUTION: Temperatures of the heater for thermal fixing of an electrophotographic device and of the inside of the device are detected with thermistors and the temperature of the inside of the device is maintained properly by controlling the revolving speed of a fan motor so as to be the maximum revolving speed, a normal revolving speed, a standby-time revolving speed or an arbitrary revolving speed according to the detected temperatures and the operating situation of the device and, also, an energy-saving efficiency and noise prevention are achieved by lowering the electric power of a control circuit and also by reducing noise when the revolving speed of the fan motor is low while pulse controlling or voltage controlling the power source of the fan motor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for controlling the rotation of a fan for radiating heat from a heat fixing unit in an electrophotographic apparatus.

[0002]

2. Description of the Related Art In an electrophotographic apparatus, a heater is generally used for heat fixing. However, this heat stays in the apparatus and the transition temperature (5%) of the glass component contained in the toner.
When the temperature reaches 0 [° C] or higher, a phenomenon called toner caking occurs and the toner solidifies, locking the gears of the drum unit, developing device, toner container, etc., damaging the gears and causing a catastrophic failure. May cause. Further, in an electrophotographic apparatus using a polygon motor and a laser, when the temperature inside the machine rises, the oil in the bearing of the polygon motor deteriorates due to heat, thereby shortening the mechanical life of the polygon motor. Also, in a device using a brushless motor, when the temperature inside the device rises, heat dissipation of the brushless motor driver IC becomes a problem, and in a resin component having a low heat-resistant temperature, a problem such as deformation may occur.

For this reason, a cooling fan is mounted inside the device so as to prevent such a phenomenon from occurring, and the heat inside the device is forcibly removed. However, even if these devices are not used for a long time, it is very uneconomical to keep the heater power on or keep the fan motor running, and because of the recent demand for energy saving and low noise, When the device is not used for a certain period of time, a control has been proposed in which the heater is preheated to reduce the supply power, and the fan motor is also rotated at a low speed or stopped.

For example, Japanese Unexamined Patent Publication No. 9-6188 (hereinafter referred to as a first prior art) detects that a state other than a printing operation has been detected, operates a timer, and sets a heater to a preheated state after a predetermined time has elapsed. At the same time, a control method has been proposed in which the rotation of the cooling fan is reduced, or after a predetermined time elapses, the power supply to the heater and the cooling fan is stopped and the mode is shifted to the sleep mode.

Japanese Patent Application Laid-Open Nos. Hei 7-121089 (hereinafter referred to as second prior art) and Japanese Unexamined Patent Publication No. Hei 11-23439 (hereinafter referred to as third prior art) disclose a series of heat fixing operations for recording paper. A method is disclosed in which the temperature of the heater is reduced to a predetermined value, and the temperature is detected by a temperature detecting element such as a thermistor to reduce the rotation speed of the fan motor.

[0006]

However, in the first prior art, since the rotation speed of the cooling fan is lowered or stopped after a lapse of a predetermined time, if the outside air temperature becomes high, even if the predetermined time elapses, the in-flight of the cooling fan may be stopped. If the fan speed is reduced or stopped in this state, the heat accumulated in the fixing unit and the various parts in the electrophotographic apparatus will not be sufficiently removed, and the temperature in the apparatus will be reduced. , And the above-mentioned inconvenience may occur. In order to prevent these problems, there is a method of increasing the time until the rotation speed of the fan is reduced, but this is not preferable from the viewpoint of energy saving and noise prevention. That is, this method is susceptible to variations in the rotational speed of the fan motor, differences in the use environment temperature, and the like.

In the second prior art and the third prior art, the number of revolutions of the fan motor is reduced after the temperature in the machine falls to a predetermined value without being affected by the variation in the operating environment temperature and the number of revolutions of the fan motor. The problem described above does not occur. However, the fan motor rotates at a constant rotation speed until the internal temperature reaches a predetermined value, which is not satisfactory from the viewpoint of energy saving and noise prevention.

SUMMARY OF THE INVENTION In view of the above, the present invention provides a fan motor rotation control method and apparatus that obtains the optimum fan rotation speed corresponding to the temperature of the fixing unit and the temperature inside the apparatus, and also satisfies energy saving and noise countermeasures. It is intended to provide.

[0009]

According to the present invention, in order to achieve the above object, the number of rotations of an in-machine cooling fan motor is changed by changing a duty ratio of a driving pulse of the motor or by changing a driving voltage applied to the motor. Set multiple rotation control modes consisting of the maximum number of rotations, normal rotation, standby rotation, and any number of rotations selected from 0 to standby rotation, as well as power-on and low power consumption mode settings A selection routine for a fan rotation control mode other than the normal printing operation or the normal standby operation is provided according to the state of the fixing device temperature when any one of the operation states is changed immediately after / on / continuous printing operation.

That is, when the fixing device temperature is low at the time of turning on the power, the rotation is started from an arbitrary rotation mode, and when the fixing device temperature becomes higher than a predetermined temperature, the rotation is shifted to the normal rotation or the standby rotation to reduce the power consumption. When the mode is released, the maximum rotation control is performed during the printing operation, and when the printing operation is not performed, an arbitrary rotation mode is selected.After the continuous printing, the maximum rotation control is performed. When switching to the low power consumption mode, an arbitrary rotation mode and a normal rotation or standby rotation mode are selected based on the fixing device temperature, and then the fan rotation is stopped until the next operation state change.

In this way, during continuous printing in which the temperature inside the machine rises, the fan motor is rotated at the maximum number of revolutions to perform powerful exhaust cooling, and the temperature inside the machine in the standby state until the next print is completed. Therefore, when the operation is not performed for a certain period of time, the power consumption mode is set to a low power consumption mode, the heater temperature is reduced, the rotation speed of the fan motor is reduced, and finally the motor is stopped.

By setting the number of rotations of the fan motor corresponding to the internal temperature and the fixing device temperature in this manner, energy saving and low noise can be realized.

[0013]

Embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention, but are merely illustrative examples. It's just

FIG. 1 shows an example of a control device of a fan motor for cooling the inside of an electrophotographic apparatus according to the present invention. In the figure, reference numeral 1 denotes a heat roller for heat fixing of an electrophotographic apparatus using plain paper;
Is a thermistor for detecting the temperature of the heat roller 1, 3 is a thermistor for detecting the temperature inside the apparatus, 4 is thermistors 2, 3
A to convert the signal (voltage value) from analog to digital
The / D converter 5 and a fan for cooling the inside of the machine are provided with a built-in fan motor. Reference numeral 6 denotes an MPU for control, 7 denotes a gate array for storing the number of rotations of the fan motor corresponding to the internal temperature or the temperature of the heat roller 1 of the fixing device as a duty ratio of a drive pulse or a drive voltage value, and 8 denotes a gate array 7 A driver for controlling the number of rotations of the fan motor of the fan 5 in response to a signal from the fan 5, a power supply 9 for the heater 1, a switch 10
11 and 12 are resistors, and 13 is a control board on which a control circuit is mounted.

FIG. 2 shows an example of the driver 8 shown in FIG. 1, and FIG. 3 shows another example of the driver 8 as well. In the figure, reference numerals 22 and 31 denote power transistors;
5 is a pulse control circuit, 34 and 35 are switches, 36 is a Zener diode, and 51 is a motor of the fan 5 in FIG.

In the present invention, the fan motor 51 is controlled by changing the duty ratio of the pulse for driving the power supply voltage or by changing the drive voltage. The relationship between the rotation speeds is as shown in FIG. 4, and the relationship between the drive voltage and the rotation speed of the fan motor 51 when controlling by changing the voltage is as shown in FIG. 5. Therefore, the optimum rotation speed of the motor 51 of the cooling fan 5 corresponding to the temperature inside the machine, the environmental temperature, and the temperature of the heat roller 1 was experimentally obtained, and the temperature of the heat roller 1 and the inside of the machine became high by continuous printing or the like. When the maximum rotation mode of 41 or 52, the normal rotation mode of 42 or 53 when the heat roller 1 is in a steady state,
When the temperature of the heat roller 1 is lowered in the print standby state, the standby rotation mode of 43 or 54 is set, and in the low power consumption mode, any rotation mode from 0 to 44 or 55 of standby is set. The duty ratio and voltage value of the driving pulse of the fan motor 51 corresponding to the rotation mode are written in the gate array 7.

In addition, when the power supply is turned on, when the low power consumption mode is set / released, or when the operation state is changed immediately after the continuous printing operation, the fan rotation other than the normal printing operation or the normal standby operation is performed depending on the state of the fixing device temperature. A control mode selection routine is set so that the MPU 6 can instruct selection.

A description will be given of the selection routine. First, during printing, the normal rotation mode is set to the rotation speed 42 in FIG. 4 or 53 in FIG. Low noise is realized at the same time as an arbitrary rotation mode of a low rotation speed that is optimal for the standby temperature indicated by reference numeral 44 or 55 in FIG. 5, and when the fixing device temperature becomes high, the normal rotation mode of 42 or 53, or 43 or 5
The standby rotation mode 4 is set.

If the low power consumption mode is instructed without printing for a certain period of time, if the fixing device temperature is low, the operation is shifted from the arbitrary rotation mode of 44 or 55 to stop, and if the fixing device temperature is high, 42 is stopped. Alternatively, a transition is made from the normal rotation mode of 53 or the standby rotation mode of 43 and 54 to stop via the arbitrary rotation mode.

When the low power consumption mode is canceled and a print operation is instructed, the maximum rotation mode 41 in FIG. 4 or 52 in FIG. 5 is set.
4 or 55 arbitrary rotation mode.

When continuous printing is performed, the maximum rotation mode is set to 41 or 52. Immediately after continuous printing, since the fixing device temperature is high, the maximum rotation mode is continued until the temperature of the heat roller 1 reaches a specified value. When the specified value is reached, the mode is set to the arbitrary rotation mode.

The above is the selection routine of the fan rotation control mode. Next, the basic operation of the control device of the fan motor 51 according to the present invention in the case of pulse driving will be described. The thermistors 2 and 3 for measuring the temperature inside the apparatus send the voltage value divided by the resistors 11 and 12 to the A / D converter 4 as a temperature value, and the A / D converter 4 converts the value into a digital value and sends it to the MPU 6. . Then, the MPU 6 selects a rotation mode in which the fan operates at an optimum rotation speed based on the temperature value and the current operation state of the machine, and issues an instruction to the gate array 7.
Send to The gate array 7 sends a signal to the driver 8 to generate a pulse having a duty ratio corresponding to the instruction,
The pulse having the designated duty ratio is supplied to the pulse control circuit 25.
To the power transistor 22 and the fan motor 5
1 rotates at a predetermined rotation speed.

When the power of the electrophotographic apparatus is turned on,
The switch 10 in FIG. 1 is also turned on, and the heat roller 1 for the fixing device is heated. However, initially, both the thermistor 2 corresponding to the heat roller 1 and the thermistor 3 for detecting the temperature inside the apparatus detect the room temperature, and the MPU 6 determines that the power is turned on and applies the above-described power-on routine to fix the image. If the temperature of the fixing device is low, the gate array 7 is instructed to perform an arbitrary rotation mode with a low rotation speed that is optimal for an arbitrary standby temperature indicated by 44 in FIG. 4 or 53 in FIG. When the thermistor 2 detects, the normal rotation mode 42 or 53 or the standby rotation mode 43 or 54 is instructed to the gate array 7 to rotate the fan.

When a print instruction is issued in this state, M
PU6 is set to the normal rotation mode in FIG.
Is instructed to the gate array 7, and if it is a continuous printing instruction, the continuous printing routine is applied to set the maximum rotation mode to 41 or 52. However, since the fixing device temperature is still high immediately after continuous printing, the MPU 6 Maintains the maximum rotation mode until the temperature of the heat roller 1 reaches a specified value, and sets the arbitrary rotation mode when the temperature reaches the specified value.

If the printing is not performed for a certain period of time, it is notified to the MPU 6 that the time for shifting to the low power consumption mode has passed from a counter (not shown).
6 applies a low power consumption mode setting routine to shift from the arbitrary rotation mode of 44 or 55 to stop when the fixing device temperature is low, and 42 or 53 when the fixing device temperature is high.
The gate array 7 is instructed to shift from the normal rotation mode or the standby rotation mode 43 or 54 to the stop through the arbitrary rotation mode.

When the low power consumption mode is released by the print operation, the MPU 6 applies the print operation routine of the low power consumption mode release routine.
An instruction to set the maximum rotation mode of 41 in FIG. 4 or 52 in FIG. 5 is sent to the gate array 7, and if only the low power consumption mode release is instructed and the printing operation is not performed, the arbitrary rotation mode of 44 or 55 is selected. To the gate array 7.

When a paper jam such as an electrophotographic apparatus is cleared, there is a device having an interlock function for stopping various power supplies in the device, but in such a case, the fan motor is stopped. Since the internal temperature rises and the above-described trouble occurs, the fan motor is driven using a power supply not linked to the interlock.

The above is the control method and apparatus of the fan for the electrophotographic apparatus of the present invention. In the above description, the case where the driver 8 changes the duty ratio of the pulse to change the rotation speed of the fan motor has been described. Of course, the number of rotations may be controlled by changing the voltage applied to the fan motor.

The driver circuit in this case will be described with reference to FIG. 3. When the switch 34 is ON and the switch 35 is OFF, the resistor 33 is selected so as to rotate the fan motor 51 in a steady state. When OFF and 35 are ON, the voltage of the Zener diode 36 is selected so as to generate a voltage for rotating the fan motor 51 at low speed. Therefore, if the switches 34 and 35 are selectively turned on and off by a signal from the MPU 6, normal rotation and low-speed rotation, and then the switch 3
By turning off both 4 and 35, the fan motor 5
You can create 3 modes to stop 1 rotation,
Three states can be selected. Switch 3
5 and a zener diode 36, and by selecting a zener diode that generates a voltage such that the fan motor 51 can achieve the maximum rotation or arbitrary rotation, the same control as that described with reference to FIG. 2 can be performed.

In place of the switches 34 and 35, D /
A predetermined voltage can be applied to the base of the power transistor 31 by using an A converter so that an arbitrary rotation speed from the maximum rotation, the normal rotation, the standby rotation, and 0 to the standby rotation can be obtained. Good.

In the above description, the case where the heat roller 1 is used as the fixing device has been described. However, various types of fixing devices other than the heat roller are used. What you can do is obvious.

It is obvious that the number of revolutions of the fan motor 51 may be controlled more finely, and those skilled in the art can easily configure the number of revolutions.

[0033]

As described above in detail, according to the present invention, the temperature of the heat fixing heater and the inside of the apparatus are detected by the thermistor, and the detected number of rotations of the fan motor is set to the maximum number of rotations, normal rotation, and standby. By controlling rotation and arbitrary rotation to keep the temperature inside the machine properly, the power of the fan motor is controlled by pulse control or drive voltage change, and at low speed rotation the power of the control circuit can be reduced, so energy saving effect And a large effect can be obtained, for example, the noise prevention can be satisfied.

[Brief description of the drawings]

FIG. 1 is an embodiment of a control device for an in-machine cooling fan of an electrophotographic apparatus according to the present invention.

FIG. 2 shows an embodiment of a driver circuit of a control device for a cooling fan in an electrophotographic apparatus according to the present invention.

FIG. 3 shows another embodiment of the driver circuit of the control device for the cooling fan in the electrophotographic apparatus according to the present invention.

FIG. 4 is a diagram showing a relationship between a duty ratio of a driving pulse of a power supply of a fan motor and a rotation speed.

FIG. 5 is a diagram showing a relationship between a voltage of a power supply supplied to a fan motor and a rotation speed;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Heat roller 2 Thermistor which detects temperature of heat roller 1 3 Thermistor which detects temperature in machine 4 A / D converter 5 Fan for cooling inside machine 6 MPU 7 Gate which stores rotation speed of fan motor as duty ratio of drive pulse Array 8 Driver for controlling rotation of fan motor 9 Power supply for heater 1 10 Switch 11 Resistance 12 Resistance 13 Control board on which control circuit is mounted 22 Power transistor 23 Resistance 24 Resistance 25 Pulse control circuit 31 Power transistor 32 Resistance 33 Resistance 34 Switch 35 Switch 36 Zener diode 51 Fan motor

Claims (8)

[Claims] 1. A plurality of rotation speeds of an internal cooling fan mounted at a predetermined position of an electrophotographic apparatus, the rotation speed being selected from a maximum rotation, a normal rotation, a standby rotation, and 0 to a standby rotation. In addition to setting the rotation control mode, when the power is turned on, when the low power consumption mode is set / released, or when any operation state is changed immediately after the continuous printing operation, depending on the state of the fixing unit temperature, the normal printing operation or the normal standby mode is performed. A method for controlling a fan for an electrophotographic apparatus, comprising a routine for selecting a rotation control mode of the fan other than the operation. 2. When the temperature of the fixing unit is low when the power is turned on,
2. The method according to claim 1, wherein the rotation is started from an arbitrary rotation mode, and when the temperature of the fixing unit becomes equal to or higher than a predetermined temperature, the rotation is shifted to a normal rotation or a standby rotation. 3. The fan for an electrophotographic apparatus according to claim 1, wherein the maximum rotation control is performed during a printing operation when the low power consumption mode is released, and an arbitrary rotation mode is selected during a non-printing operation. Control method. 4. The method of controlling a fan for an electrophotographic apparatus according to claim 1, wherein the maximum rotation control is performed immediately after the continuous printing, and the mode is shifted to an arbitrary rotation mode after reaching a known predetermined temperature. 5. The method according to claim 1, wherein when shifting to the low power consumption mode, an arbitrary rotation mode and a normal or standby mode are selected based on the temperature of the fixing device, and then the fan rotation is stopped until the next operation state change. Item 3. A method for controlling a fan for an electrophotographic apparatus according to Item 1. 6. The method of controlling a fan according to claim 1, wherein the fan motor can be rotated at a maximum rotation, a normal rotation, a standby rotation, or an arbitrary rotation by changing a duty ratio of a driving pulse. Of controlling a fan for an electrophotographic apparatus. 7. An in-machine cooling fan attached to a predetermined position of an electrophotographic apparatus, a fan having a motor configured to be driven by a pulse, a thermistor for detecting a thermal fixing device temperature and an in-machine temperature, Rotation, standby rotation, 0
A fan motor having a duty ratio corresponding to a temperature detected by the thermistor and an operating condition of a machine by storing a duty ratio of a pulse corresponding to a plurality of rotation control modes including an arbitrary number of rotations selected until a standby rotation. And a control circuit for outputting a driving pulse.When a power is turned on or when a power consumption mode is switched, and further when a print state is changed, a duty ratio control signal is transmitted to the control circuit to control the rotation of the fan. Control device for fan for electrophotographic apparatus 8. The control circuit according to claim 7, wherein the A / D converts a signal from the thermistor from analog to digital.
A converter and a gate array storing pulse duty ratios corresponding to a plurality of rotation control modes consisting of a maximum rotation, a normal rotation, a standby rotation, and an arbitrary number of rotations selected from 0 to a standby rotation; An MPU for receiving a signal from the A / D converter and instructing the gate array to output the number of rotations corresponding to a power-on or switching of a power consumption mode, and further to a change in a printing state, and outputting the same. Control device for fan for electrophotographic device.