JPH02244179A - Method for controlling preheating temperature of heat fixing roller of facsimile device - Google Patents

Abstract

PURPOSE:To eliminate the need for a mechanism for measuring an ambient temp. and to suppress the increase of a device cost by setting an excess heat temp. in accordance with the tendency of a heat fixing roller to a temp. rise or the time required for the temp. thereof to rise actually up to a fixing temp. CONSTITUTION:A heater 3 is operated to heat the heat fixing roller 2 up to a preheating temp. and the preheating temp. is reset in accordance with the time required for the temp. of the heat fixing roller 2 to attain the preheating temp. when the temp. of the heat fixing roller 2 falls below the preheating temp. during standing by for recording. The preheating temp. is otherwise reset in accordance with the time required for the temp. of the heat fixing roller 2 to attain the fixing temp. from the preheating temp. The need for the mechanism for measuring the ambient temp. is eliminated in this way and, therefore, the increase of the device cost is suppressed. Since the preheating temp. is set in accordance with the ambient temp., the preheating temp. can be set at an adequate value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for preheating a heat fixing roller of a facsimile machine equipped with an image recording device that forms a recorded image using an electrophotographic process.

[Prior Art] Generally, in facsimile machines, a thermal recording type image recording device that records an image on thermal recording paper using a thermal head is widely used. has the problem of poor storage stability.

Therefore, in recent years, image recording apparatuses that form recorded images using an electrophotographic process, which can form recorded images with good storage stability, have been used in some high-end machines.

In an image recording device that uses this electrophotographic process, a drum-shaped or belt-shaped photoreceptor whose surface is charged at a high voltage and moves at a constant speed is exposed to image light modulated by recorded image data, and the surface of the photoreceptor is An electrostatic latent image corresponding to the recorded image is formed on the photoreceptor, and the electrostatic latent image is developed with toner to form a toner image on the surface of the photoreceptor.

Then, the toner image is transferred onto recording paper, and the toner image on the recording paper is thermally fixed by a heat fixing roller, thereby forming a recorded image.

In addition, methods for generating one image light include a laser beam method in which a laser beam is modulated line by line with recording data to form image light, and a laser beam method in which light from a linear light source is turned on and off by a liquid crystal shutter in pixel units to generate image light. There is a liquid crystal shutter method that forms the screen.

Now, in an image recording device that uses an electrophotographic process, if the temperature of the heat fixing roller does not reach a predetermined fixing temperature, the image cannot be fixed on the recording paper to which the toner image has been transferred. During standby, the heat fixing roller is heated to a certain temperature (hereinafter referred to as preheating) so that the temperature of the heat fixing roller can reach the fixing temperature by the time the recording paper reaches the heat fixing roller. There is.

There are two main methods for preheating the heat fixing roller:

■ Preheat the heat fixing roller to the fixing temperature.

■ Preheat the heat fixing roller to a temperature lower than the fixing temperature (hereinafter referred to as preheating temperature).

[Problems to be Solved by the Invention] However, such conventional preheating methods have the following problems.

First, with the conventional method, the internal temperature of the facsimile machine becomes too high, the reliability of the parts decreases significantly, and the power consumption also increases considerably.In order to lower the internal temperature of the facsimile machine, a heat exhaust fan is installed. Although it is conceivable to provide a fan, it is necessary to constantly drive this fan, which further increases power consumption.

In conventional method (2), when the preheating temperature is low and the ambient temperature is low, it takes a long time to raise the temperature from the preheating temperature to the fixing temperature.

In a facsimile machine, after starting the reception operation, heating of the heat fixing roller to the fixing temperature is started, but by the time the recording paper on which the toner image of the first page image is transferred reaches the heat fixing roller. If the temperature of the heat fixing roller does not reach the fixing temperature, the toner image cannot be fixed on the recording paper.
Therefore, if the time required for the temperature to rise from the preheating temperature to the fixing temperature is longer than the time from the start of reception operation until the first page of recording paper reaches the heat fixing roller, the toner image on that recording paper This results in the inconvenience that it is not possible to heat-fix the image.

In order to eliminate such inconveniences, for example,
As disclosed in Publication No. 041354.

There is also a method of measuring the ambient temperature and setting the preheating temperature according to the measurement result, but this method requires a mechanism for measuring one ambient temperature, resulting in an increase in device cost.

The present invention has been made in view of the above circumstances, and provides a heat fixing roller preheating temperature for a facsimile machine that allows the time required to rise to the fixing temperature to be within a specified value and suppresses increases in device costs. The purpose is to provide a control method.

[Means for Solving the Problems] In the present invention, when the temperature of the heat fixing roller falls below the preheating temperature during recording standby, the heater is activated to heat the heat fixing roller to the preheating temperature. Depending on the time it takes for the fusing roller temperature to reach the preheating temperature, reset the preheating temperature, or set the preheating temperature again depending on the time it takes for the thermal fusing roller temperature to reach the fusing temperature from the preheating temperature. This is to reset the .

[Function] Therefore, since the preheating temperature is set based on the tendency of temperature rise of the heat fixing roller or the time required to actually rise to the fixing temperature, it is possible to set the preheating temperature to an appropriate value. can. Further, a mechanism for measuring the ambient temperature is not required, and an increase in device cost can be suppressed.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a temperature control device for a heat fixing roller according to an embodiment of the present invention.

In the same figure, a control unit 1 is for controlling the temperature of the heat fixing roller, and exchanges various information with a system control unit (not shown) of the image recording device to control preheating of the heat fixing roller. , and performs fixing temperature control.

The heat fixing roller 2 is used in an electrophotographic process.

The heater 3 is used to heat the heat fixing roller 2, and the heater 3 is used to heat the heat fixing roller 2 to fix the image onto a recording paper (not shown) onto which the toner image has been transferred.

As the heater 3, for example, a halogen lamp or the like is used.

The heater drive circuit 4 is driven by a command from the control unit l.

This is for applying the AC power source 5 to the heater 3 at a constant duty.

The temperature detection circuit 6 is for detecting a change in the resistance value of a thermistough provided near the heat fixing roller 2, and measuring the temperature of the heat fixing roller 2 based on the detection result. The measurement results are output to the control section 1.

The timer circuit 8 measures the time from the start to the end of the time counting operation, and its start/stop/clearing is controlled by the control unit 1.

With the above configuration, the preheating recovery time of the heat fixing roller 2 at typical ambient temperatures is measured in advance and stored in the control section l.

As shown in FIG. 2, this preheating return time is determined when the temperature of the heat fixing roller 2 falls below the preheating temperature Tp.
After turning on, the temperature of the heat fixing roller 2 reaches the preheating temperature TP.
This is the time tp required to return to . Further, the preheating return time tp becomes longer when the ambient temperature is low, and becomes shorter when the ambient temperature is high. Therefore, by measuring the preheating return time tp, the ambient temperature can be determined with a certain degree of accuracy.

Further, the preheating temperature tp is set to the minimum temperature at which the time required for the temperature of the heat fixing roller 2 to rise from the preheating temperature Tp to the fixing temperature Tt is within a specified value at a constant ambient temperature. Yes, and can be determined experimentally.

In this example, three representative ambient temperatures, namely:
Temperature Tll, which is lower than normal temperature by a certain value, normal temperature T12. Regarding the three types of temperature T13, which is higher than room temperature by a certain value,
Each preheating temperature element 1. T2. T3 and preheating return time tl, t2. t3 is measured and stored in the control unit l.

Here, TI>T2>T3 and tl>t2>t3.

The control unit 1 performs the process shown in FIG. 3 during recording standby, thereby preheating the heat fixing roller 2.

That is, this process is started when the power is turned on, and first, process 10 is performed to set the preheating temperature TP to the temperature T2 at room temperature.
1) Check whether the roller temperature Th manually input by the temperature detection circuit 6 is smaller than the preheating temperature tp (determination 102).
, when the result of judgment 102 is NO, wait until the roller temperature Th becomes smaller than the preheating temperature TP.

If the result of judgment 102 is YES, heater drive circuit 4
Process 1 to turn on heater 3 by outputting a heater drive command to
03) Immediately after clearing the timer circuit 8, the timing operation is started (processing 104).

In this state, wait until the roller temperature Th reaches the preheating temperature 12 or higher (NO loop of judgment 105), and if the roller temperature Th becomes the preheating temperature 19 or higher and the result of judgment 105 becomes YES, at that point the heater Process 10 to output a heater drive stop command to the parking circuit 4 and turn off the heater 3
6) Stop the time counting operation of the timer circuit 8 and store the measured value as the preheating return time tp (process 107).
.

Then, the preheating return time tp is (tl+t2)/2
Check whether the value is greater than or equal to the value (judgment 108), and
When the result is NO, the preheating return time tp becomes (t
2+t3) Check whether it is smaller than 12 (judgment 1
09).

When the result of judgment 108 is YES, the preheating return time tp is lower than the ambient temperature T2 than the preheating return time t2 at room temperature.
Since the case is close to or greater than the preheating return time tl when the ambient temperature is Tll, the preheating temperature Tp is reset to the preheating temperature TI when the ambient temperature is Tll (processing 110), and judgment 102
Return to

Further, when the result of judgment 109 is '/ES, the preheating return time tp is closer to or smaller than the preheating return time t3 at ambient temperature T13 than the preheating return time t2 at normal temperature, so the preheating Temperature Tp is ambient temperature T13
The preheating temperature is reset to T3 (processing 111).

Return to decision 102.

Also, if the result of judgment 108 is NO, and judgment 10
When the result in step 9 is No, the preheating return time tp is within the range of the preheating return time t2 at normal temperature, and the condition is in the prescribed condition, so the preheating temperature Tp is not reset. Return to decision 102.

In this way, during recording standby, the preheating temperature Tp is reset based on the measurement result of the preheating return time tp, so that an appropriate preheating temperature Tp can be set without having an ambient temperature measurement mechanism. You can make settings.

Furthermore, this process ends when the system control unit notifies the start of recording.

By the way, in the embodiment described above, three ambient temperatures T11. T12. For the case of T13, the preheating temperature TI, T2. T3 and preheating return time tl, t
Although 2°T3 is measured and stored in the control unit l, the preheating temperature rp can also be set based on the actual temperature increase tendency.

That is, as shown in FIG. 4, first, with the preheating temperature TP set at a constant temperature, the heater 3 is turned on to heat the heat fixing roller 2, and the temperature of the heat fixing roller 2 changes from the preheating temperature Tp. The time ta required to reach the fixing temperature Tt is measured.

Then, a linear equation is calculated based on the measured time ta and the preheating temperature 'rp at that time to update the preheating temperature Tp.

Tp=Tt-((Tt-Tp)·tb)/la FIG. 5 shows an example of the processing executed by the control unit 1 when performing such processing.

First, the preheating temperature TP is set to the default value Td (for example, the preheating temperature T2 at room temperature) (step 201), and the roller temperature Th input from the temperature detection circuit 6 becomes smaller than the preheating temperature TP, or the recording start is stopped. It waits until a command is input (NO loop of judgments 202 and 203).

Find out if it's okay.

The roller temperature Th becomes smaller than the preheating temperature TP, and judgment 2 is made.
When the result of 02 becomes '/ES, the process 204 outputs the heater drive circuit to the heater drive circuit 4 and turns on the heater 3.
), waits until the roller temperature Th becomes preheating temperature 12 or higher or a command to start recording is input (Judgment 2)
05,206 NO loop).

When the roller temperature Th becomes equal to or higher than the preheating temperature Tp, judgment 205 is made.
When the result becomes '/ES, at that point a heater drive stop command is output to the heater drive circuit 4 to turn off the heater 3 (process 207), and the process returns to judgment 202.

In this way, during recording standby, the drive of the heater 3 is controlled so that the temperature of the heat fixing roller 2 matches the preheating temperature Tp.

In this state, when the system control unit commands to start recording and the result of judgment 1 203 or 206 becomes YES, the heater 3 is turned on and at the same time the timer circuit 8 starts timing operation (processes 208 and 209), and heat fixing is performed. roller 2
Waits until the temperature of the roller increases and the roller temperature Th becomes equal to or higher than the fixing temperature Tt (NO loop of judgment 210).

When the roller temperature Th reaches the fixing temperature Tt and the result of the first judgment 210 becomes YES, at that point the heater 3 is turned off (process 211), the time counting operation of the timer circuit 8 is stopped, and the measured value is set at the time ta. (processing 212).

Then, the preheating time Tp is calculated by executing the calculation process of the above formula.
213), and waits until the roller temperature Th becomes smaller than the fixing temperature Tt or until the system control unit notifies the end of recording (judgment 214, 2).
15 NO loops).

When the thermal fixing roller 2 cools down and the roller temperature Th becomes smaller than the fixing temperature Tt, and the result of the first judgment 214 becomes YES, the heater is turned on fi216), thereby heating the thermal fixing roller 2 and The process waits until the temperature Th becomes equal to or higher than the fixing temperature Tt (NO loop of judgment 217) 6. If the result of judgment 217 becomes YES, the heater is turned off (process 218), and the process returns to process 214.

In this manner, during the recording operation, the temperature of the thermal fixing roller 2 is controlled to be the fixing temperature Tt.

Also, the end of recording is notified and the result of judgment 215 is YES.
When this happens, the process returns to judgment 202 and transitions to a recording standby state.

In this way, in this embodiment, the preheating temperature Tp is reset based on the time required to rise from the preheating temperature Tp to the fixing temperature Tt, so the preheating temperature Tp is set more suitable for the ambient temperature. Can be used.

Furthermore, in the above-mentioned embodiments, the temperature rise of the heat fixing roller 2 was explained as having a linear function-like tendency with time as a variable, but if the temperature rise function is other than that, The preheating temperature can be reset using the function.

Note that the present invention can be applied to any facsimile machine that uses an image recording device that creates images using an electrophotographic process.

Further, as the heater for the heat fixing roller, other than the above-mentioned halogen lamp can also be used. Further, the duty for driving the heater may be set appropriately.

[Effects of the Invention] As explained above, according to the present invention, during recording standby,
When the temperature of the heat fixing roller falls below the preheating temperature, the heater is activated to heat the heat fixing roller to the preheating temperature. Reset the preheat temperature or.

The preheating temperature is reset according to the time required for the temperature of the heat fixing roller to reach from the preheating temperature to the fixing temperature, and as there is no need for a mechanism to measure the ambient temperature, equipment costs are reduced. increase can be suppressed. Moreover, since the preheating temperature is set according to the ambient temperature, an effect is obtained in that the preheating temperature can be set to an appropriate value.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a temperature control device for a heat fixing roller according to an embodiment of the present invention, FIG. 2 is a schematic diagram for explaining preheating return time, and FIG. 3 is an example of preheating processing performed during recording standby. FIG. 4 is a graph for explaining another example of resetting the preheating temperature, and FIG. 5 is a flowchart showing an example of temperature control of the heat fixing roller. l...Control unit, 2...Heat fixing roller, 3...Heater, 4...Heater drive circuit, 6...Temperature detection circuit,
7... Thermistor, 8... Timer circuit. Figure 1 Figure 2 Figure 4 Rope tlL pulling

Claims (2)

[Claims] (1) In a heat fixing roller preheating control method for a facsimile machine equipped with an image recording device that forms a recorded image using an electrophotographic process and fixes the recorded image with a heat fixing roller, the temperature of the heat fixing roller during recording standby is When the temperature drops below the preheating temperature, the heater is activated to heat the fixing roller to the preheating temperature, and the preheating temperature is reset depending on the time required for the temperature of the fixing roller to reach the preheating temperature. A method for controlling the preheating temperature of a heat fixing roller in a facsimile machine. (2) In a heat fixing roller preheating control method for a facsimile machine equipped with an image recording device that forms a recorded image using an electrophotographic process and fixes the recorded image with a heat fixing roller, the temperature of the heat fixing roller varies from the preheating temperature. A method for controlling a preheating temperature of a heat fixing roller in a facsimile machine, characterized in that the preheating temperature is reset according to the time required to reach the fixing temperature.