JP3387237B2 - Temperature control method of heat fixing device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature control method for a heat fixing device for fixing a substance to be fixed on a recording medium by heat.

[0002]

2. Description of the Related Art Conventionally, for example, in a copying machine, when a toner as a substance to be fixed is fixed on a recording medium such as paper,
As a method for controlling the temperature of the heating and fixing device, power consumption is reduced by lowering the set target temperature after a lapse of a certain time after completion of copying. For example, JP-A-60-16
In Japanese Patent No. 9877, a certain temperature (first set temperature T10) at which the heat fixing device can be copied is maintained, and when a copy start command is supplied, the temperature is raised to a second set temperature T30 higher than that. Make a copy. At this time, heat is taken by the recording medium, which is a sheet, so that the temperature of the heat fixing device drops to the temperature T20. Then, when a certain time has elapsed after the copying is completed, the temperature control is performed again so as to maintain the first set temperature T10. In addition, JP-A-4-3
In Japanese Patent No. 43369, the temperature in the preheating mode of the heat fixing device is set based on the past usage status and the time since the last usage.

[0003]

However, the above-described conventional temperature control method for the heat fixing device (Japanese Patent Laid-Open No. 60-1).
In Japanese Patent Publication No. 69877), the usage conditions are completely different depending on the installation location, and there are cases in which only a few copies are made at all times, and sometimes dozens or hundreds of copies are made each time. The first set temperature T10 is not necessarily a reasonable temperature, and there is a problem that the power consumption cannot always be reduced. Further, in the temperature control method of the heat fixing device (Japanese Patent Laid-Open No. 4-343369), the temperature in the preheating mode at startup can be adjusted, but conditions such as the number of copies and reduction / enlargement are set for each copy. This is not taken into consideration, and as described above, the temperature is not set appropriately for each copy, and there is a problem that power consumption cannot always be reduced.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a temperature control method for a heating and fixing device, which can maintain the temperature according to the use condition of the heating and fixing device and can reduce power consumption. I am trying.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is a temperature control method for a heat fixing device, which holds the heat fixing device at a temperature control target value. From the usage history in which the degree of decrease is stored, the temperature decrease that is expected to occur when copying under the current usage conditions is read out and used as the expected temperature decrease, and the actual temperature decrease is indicated after the copy is completed. The actually measured temperature decrease is calculated, and if the actually measured temperature decrease is larger than the expected temperature decrease, the temperature decrease retained in the usage history is updated to the actually measured temperature decrease, and every time copying is repeated a certain number of times. Or every time a certain period of time elapses, the temperature control target value is changed according to the maximum value of the actually measured temperature decrease during that period. Further, the present invention is a temperature control method for a heating and fixing device that holds the heating and fixing device at a temperature control target value, which is copied under current usage conditions from a usage history in which the temperature decrease of the heating and fixing device is stored. When the expected temperature decrease is read, the expected temperature decrease is determined, and it is determined whether the estimated temperature decrease is less than or equal to a threshold value. If the determination result is negative. On the other hand, while changing the temperature control target value so as to increase according to the expected temperature decrease degree, if the determination result is affirmative, copy is executed under the use condition, and after the copy is finished, If the measured temperature decrease is larger than the expected temperature decrease, the measured temperature decrease indicating the temperature decrease is updated to the measured temperature decrease stored in the usage history . Copy a certain number of times For each repetition, or, each time elapses a predetermined time, and changing the temperature control target value in accordance with the maximum value of the measured temperature drop degree of between.

[0006]

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. 1 and 2 are flowcharts showing a temperature control method for a heat fixing device according to an embodiment of the present invention. Further, FIG. 3 is a time chart showing a temperature change of the heat fixing device in the embodiment. First, step S1
At, ΔTm is initialized as Ta− (Tb + α). ΔTm is the maximum value of ΔTd shown in FIG. 3, Ta is the current target set temperature, and Tb is the minimum temperature. In step S2, the variable n that counts the number of times the temperature is monitored is set to "0". Next, in step S3,
Set the copy mode. Settings include paper size,
Number of copies, enlargement / reduction ratio (hereinafter referred to as reduction / enlargement ratio)
Etc. Next, in step S4, based on the data of the above-mentioned paper size, reduction / magnification ratio, and the number of copies, the temperature decrease table shown in FIG. 4 is referred to and the corresponding data is read. Here, FIG. 4 is a temperature drop table in which the temperature drop of the heating and fixing device that has been experimentally measured in advance is stored. For example, in the case of A3 paper size, the scaling factor is 1.
At 100%, when 1 to 10 copies are made, a temperature decrease of 4 deg occurs, and when 51 to 100 copies are made, 15
It is shown that the temperature drops by deg and the temperature drops by 25 deg when copying 501 to 1000 sheets. In step S4, the data A of this temperature decrease rate table is read and used as the expected temperature decrease rate ΔT1. It should be noted that the temperature decrease table is updated in the process described later.

Next, in step S5, it is determined whether or not the predicted temperature drop ΔT1 is ΔTm or less. △
Tm is the maximum value of ΔTd shown in FIG. 3, and ΔTd is set on the basis of the above data A, that is, the expected temperature decrease ΔT1, and when the temperature of the heat fixing device is lowered during copying. The temperature control target value TL is a value that regulates the temperature control target value TL when the heat fixing device is maintained at a constant temperature so that the temperature does not become lower than the minimum temperature Tb at which copying is possible. Note that FIG.
“Α” shown in is a margin. Here, when the expected temperature decrease ΔT1 is equal to or less than ΔTm, that is, the temperature decrease read from the temperature decrease table based on the data of the paper size, the enlargement / reduction rate, and the number of copies is the maximum value Δ. Tm
If the temperature is below, the temperature of the heat fixing device will not exceed the maximum value ΔTm and be equal to or lower than the minimum temperature Tb even when copying under the present conditions. On the other hand, the expected temperature drop ΔT1 is Δ
When it becomes larger than Tm, when copied under the current conditions,
Since the temperature drop exceeds the maximum value ΔTm, the minimum temperature Tb
May be lower.

Here, when the expected temperature drop ΔT1 is ΔTm or less, that is, when the temperature of the heat fixing device does not fall below the minimum temperature Tb even when copying under the present conditions, The determination result in step S5 is "YE
S ”, and the process proceeds to step S6. In step S6,
Copying is started according to the copy mode set in step S3. When the predetermined number of copies are completed, then
In step S7, the copying ends. Next, in step S8, the temperature T2 of the heat fixing device is detected, and this temperature T2 is subtracted from the current target set temperature Ta to calculate the actually measured temperature decrease ΔT2 at the end of copying. In step S9, it is determined whether or not the actually measured temperature decrease ΔT2 is larger than the expected temperature decrease ΔT1. That is, each time a series of copying is completed, it is determined whether the actual temperature decrease of the heat fixing device, that is, the actually measured temperature decrease ΔT2 is larger than the expected temperature decrease ΔT1 read from the temperature decrease table. .

If the actually measured temperature decrease ΔT2 is larger than the expected temperature decrease ΔT1 described above, that is, if the temperature decrease of the heat fixing device after copying is larger than the expected temperature decrease, the step S9 is performed. The judgment result is "Y
ES ”, and the process proceeds to step S10. Step S10
Then, in order to update the expected temperature decrease ΔT1 read from the heating decrease table and the data A of the heating decrease table, after substituting the actually measured temperature decrease ΔT2 into the expected temperature decrease ΔT1 and the data A, Step S1 shown in FIG.
Go to 1. On the other hand, the measured temperature decrease ΔT2 of the heat fixing device is the expected temperature decrease ΔT read from the temperature decrease table.
If it is 1 or less, the determination result in step S9 is "N.
It becomes "O", and the process proceeds to step S11 without performing the above update.

In step S11, it is determined whether the variable n is "0". The variable n is incremented each time the temperature of the heat fixing device is detected in a step described later, and when the number of times reaches a predetermined number (200 times in this embodiment),
It is reset to "0". Here, when the variable n is “0”, that is, when the temperature is reset for the first time,
The determination result in step S11 is “YES”,
In step S12, the predicted temperature decrease ΔT1 is substituted into ΔTd to update it. On the other hand, if the variable n is not "0",
The determination result in step S11 is "NO", and the process proceeds to step S13. In step S13, it is determined whether the predicted temperature decrease ΔT1 is ΔTd or more. At this point, the predicted temperature decrease ΔT1 is the data A read from the temperature decrease table or the actually measured temperature decrease Δ.
T2 is substituted. If the predicted temperature decrease ΔT1 is equal to or greater than the current ΔTd, the determination result in step S13 is “YES”, and the above-described step S13 is performed.
The process proceeds to step 12, and the predicted temperature decrease ΔT1 is substituted into ΔTd for updating. On the other hand, when the predicted temperature decrease ΔT1 is smaller than the current ΔTd, the determination result in step S13 is “NO”, and the process proceeds to step S14. Step S1
In 4, ΔTd is maintained as it is.

Step S12 or Step S1
When the process of 4 is completed, the process proceeds to step S15, and the variable n
Is incremented by "1". Next, step S1
In 6, it is determined whether the variable n is "200" or more. When the variable n is “200” or more,
That is, when the temperature of the heat fixing device is detected 200 times or more, the determination result in step S16 is "YE
S ”, and the process proceeds to step S17. In step S17, the next temperature control target value TL is set to the minimum temperature Tb + ΔTd +
Since the value of ΔTd is the maximum value as a result of being continuously updated, this is set to ΔTm, and the temperature control target value Ta is set to the temperature control target value TL. Then, after determining the next set value, the process returns to step S2.

If the variable n has not reached "200", that is, if the temperature of the heat fixing device has not been detected 200 times, the determination result in step S16 is "NO", and the process proceeds to step S3. move on. Therefore,
In this case, the set value is not changed.

Further, in step S5 described above, the expected temperature decrease rate ΔT1 read from the temperature decrease degree table.
Is larger than the maximum value ΔTm, the judgment result is “N
"O" and the process proceeds to step S18. In step S18, the predicted temperature decrease ΔT1 is substituted into ΔTd. Next, proceeding to step S17 shown in FIG. 2 described above, the next temperature control target value TL is set to the minimum temperature Tb + ΔTd + α, the maximum value ΔTm of ΔTd is set to ΔTd, and the temperature control target value Ta is set to the above temperature. Let the control target value TL. Then, after determining the next set value, the process returns to step S2. After that, the setting value is changed in steps S18 and S17, and the result of the determination in step S5 is "YES". Therefore, the copy process from step S6 is executed.

As described above, in this embodiment, the actual temperature decrease of the heat fixing device is detected for each series of copying processes,
Since the holding temperature of the heat fixing device, that is, the temperature control target value Ta is set according to the expected temperature decrease ΔTd which is the maximum temperature decrease in the usage situation in which the heat fixing device is used, the heat fixing device is set. Since the temperature can be maintained at the optimum temperature according to the usage status of, the power consumption can be reduced.
Further, if the temperature control target value Ta is lower than the conventional holding temperature, the waiting time at warm-up can be shortened.

In the above-described embodiment, the temperature control target value Ta is set based on the largest expected temperature drop ΔTd of the 200 copying operations. However, in addition to the number of copying operations, Using the timer value that counts a predetermined time, the largest expected temperature drop ΔT during that time
The temperature control target value Ta may be set based on d.

[0017]

As described above, according to the present invention, when maintaining the fixable state, the temperature can be maintained according to the usage status of the heat fixing device, and the power consumption can be reduced. Is obtained.

[Brief description of drawings]

FIG. 1 is a flowchart showing an operation of a copying apparatus to which a temperature control method for a heat fixing apparatus according to an exemplary embodiment of the present invention is applied.

FIG. 2 is a flowchart showing the operation of the copying machine to which the temperature control method of the heat fixing device according to the present embodiment is applied.

FIG. 3 is a time chart showing changes in temperature of the heat fixing device of this embodiment.

FIG. 4 is a conceptual diagram showing a temperature decrease degree table in which the temperature decrease degree of the heat fixing device measured experimentally in advance is stored.

FIG. 5 is a time chart showing a temperature change of a conventional heat fixing device.

[Explanation of symbols]

Ta temperature control target value TL Temperature control target value Tb minimum temperature △ T1 Expected temperature drop △ T2 Actual temperature drop T2 Temperature of heat fixing device △ Tm maximum value

Claims (2)

(57) [Claims] 1. A temperature control method of the heat-fixing device for holding the heat fixing device temperature control target value, the use history of temperature drop of the heat fixing device are stored,
The temperature drop rate that is expected to occur when copying under the current usage conditions is read and used as the predicted temperature drop rate, and after the copying is completed, the actually measured temperature drop rate that indicates the actual temperature drop rate is calculated, and the If the actually measured temperature decrease is larger than the expected temperature decrease, the temperature decrease retained in the usage history is updated to the actually measured temperature decrease, and every time copying is repeated a fixed number of times or a fixed time elapses. In addition, the temperature control method of the heat fixing device is characterized in that the temperature control target value is changed in accordance with the maximum value of the actually measured temperature drop during that period. 2. A temperature control method of the heat-fixing device for holding the heat fixing device temperature control target value, the use history of temperature drop of the heat fixing device are stored,
The temperature drop rate expected to occur when copying under the current use conditions is read, and the predicted temperature drop rate is determined, and it is determined whether or not the expected temperature drop rate is equal to or less than a threshold value, and the determination is made. If the result is negative, the temperature control target value is changed according to the predicted temperature decrease, and if the result of the determination is affirmative, copying is executed under the usage conditions. Then, after the copy is completed, the actually measured temperature decrease indicating the actual temperature decrease is calculated, and if the actually measured temperature decrease is greater than the expected temperature decrease, the temperature decrease retained in the usage history is actually measured. It is characterized in that the temperature control target value is changed in accordance with the maximum value of the actually measured temperature decrease degree during updating to the temperature decrease degree and repeating the copying a certain number of times or every elapse of a certain time. heating Temperature control method of wearing the device.