JPH0262575A - Fixing device - Google Patents

Abstract

PURPOSE:To carry out heating according to a selected heating pattern and to prevent a fixation part from being overheated by selecting the best heating pattern among fixation heating patterns prepared corresponding to applied source voltages by the fixing device according to the temperature gradient of the temperature rise of a fixation part after the power source is turned on. CONSTITUTION:When the fixation device is powered on, a heat generates heat and a thermistor 3 detects the surface temperature of a fixing roll 2 and judges whether or not its detected temperature exceeds specific temperature. Then when the detected temperature exceeds the specific temperature, the time begins to be measured and when the surface temperature of the roll 2 rises above a specific value, the time clocking is stopped at the time. Then a temperature gradient detection part 5 calculates the temperature gradient in the time required for the rise in the detected temperature of the roll 2 from the 1st specific value to the 2nd specific value. A selection part 6 selects whether or not this temperature gradient matches the heating patterns A and B set in a storage part in advance and a heating control part 7 prevents the heater 1 from being controlled excessively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heating type fixing device that can handle differences in input power supply voltage with one type of heater. The fixing device of the present invention can be used as a fixing device for copying machines and the like that are shipped to multiple regions with different power supply voltages.

[Prior Art] Traditionally, heating type fixing devices used in copying machines, etc.
After the heating heater is heated by the turned on power and the temperature of the fixing section rises to a predetermined temperature, ON-OFF control is performed to maintain this temperature constant. Here, since the time required for the fixing section to reach a predetermined temperature after the power is turned on is a waiting time for use of the copying machine, etc., it is desirable that the time be as short as possible.

However, when heated to reach a predetermined concentration in a short period of time,
Excessive heating (overshoot) may occur. As a countermeasure to this, predetermined heating control has been carried out. Furthermore, the conventional fixing device uses six heaters with different electrical resistances for each power supply voltage in regions with different power supply voltages.

[Problems to be Solved by the Invention] However, in the conventional fixing device described above, when the heater is used in regions where the power supply voltage used to heat the heater is different, if the same heater is used, the power supply voltage applied may cause a unit time difference. 1. Since the heat generation of different heaters is significantly different, the transient excessive heating (overshoot) after power is turned on may become excessive and damage the heater, or the time to reach the specified temperature may be significantly delayed. The conventional heating υ control of the fixing device could not cope with this problem, so
The countermeasure was to replace the heater with one that has an electrical resistance that corresponds to the power supply voltage of the area where it is used. Therefore, it was necessary to replace the heater each time depending on the power supply voltage used, and also to carry out administrative procedures and other associated tasks. The economic loss caused by this reduction in work efficiency was too large to be ignored.

Therefore, an object of the present invention is to enable the same heater to be used even in regions where the electric fl voltage used is different, without having to change the heater for each input voltage.

[Means for Solving the Problems] A fixing device of the present invention includes a fixing section having a heater, a fixing section temperature detection sensor for detecting the temperature of the fixing section, and a fixing section for heating the fixing section to a predetermined temperature. a storage section that stores a plurality of heating patterns; a temperature gradient calculation section that calculates the temperature gradient of the fixing section temperature based on a detection signal from the fixing section temperature detection sensor; The apparatus is characterized in that it includes a selection section that selects a heating pattern, and a heating control section that controls heating of the heater in accordance with the optimum heating pattern selected by the selection section.

The heating pattern stored in the storage unit constituting the fixing device of the present invention is configured by setting values of various parameters that characterize the heating pattern. The parameters include, for example, heating control start temperature, duty ratio of ON-OFF pulse control, steady state control transition temperature, and the like.

Among the various heating patterns based on these parameters, a simple type of heating pattern is one in which only the heating control start temperature is set to a different value depending on the applied power supply voltage, and the other parameters are set to the same value. There is a heating pattern in which only the duty ratio of the ON-OF pulse L control is set to a different value depending on the applied power supply voltage, and the other parameters are the same.

Further, there are two set temperatures e used in the temperature gradient calculation section: a temperature TS at which time measurement is started and a temperature Te at which time measurement is ended. The temperature range Te of these set temperatures Ts and Te
-Ts is set to a width that is appropriate when calculating the temperature gradient. The set temperature Te must be within a range that allows subsequent heating control to be appropriately controlled even when the temperature gradient is the highest.
It is desirable to set it high. Conversely, it is also possible to calculate the temperature gradient by setting the temperature gradient calculation section to a period during a predetermined time and measuring the temperature rise during that time. This is not very desirable because the temperature difference between the two temperatures varies.

A determination value αL used for determining the temperature gradient of the fixing unit at each power supply voltage is set in the selection unit for selecting the optimum pattern.

Since the temperature gradient at each power supply voltage is calculated by the temperature rise of the fixing unit due to the amount of heat generated by the heater at that voltage, the intermediate value between these temperature gradients is adopted as the discrimination value αL. Therefore, the number of discrimination values αL is the number obtained by subtracting 1 from the number of types of power supply voltages. For example, 21! If the power supply voltage is of the same type, the only judgment value is αt, and if there are three types of power supply voltage, the judgment value is α1. There are two α2.

[Function] In the fixing device of the present invention, the temperature of the fixing section having a heater is constantly measured by the fixing section temperature detection sensor. The heater generates heat depending on the power supply voltage and heats the fixing section.
The temperature of the fixing section increases. The amount of heat generated by the heater is determined by the supplied power supply voltage, and for the same heater, as the power supply voltage increases, the amount of heat generated by the heater increases almost in proportion to the voltage. For example, at a power supply voltage of 120
With a 0W heater, if you use 240V, it will be 800V.
It becomes W. The temperature gradient calculating section manually inputs the detection signal of the fixing section temperature detected by the fixing section temperature detection sensor, and calculates the temperature gradient of the fixing section temperature from the time when two set temperatures TS and Te are passed. Once the temperature gradient has been calculated, the signal from the temperature gradient calculation unit is used to determine the heating pattern most suitable for the temperature gradient, which is stored in the storage unit and corresponds to each case when the voltage is applied. The selection department selects from among the patterns. According to the selected optimal heating pattern, the heating control section adjusts the power supplied to the heater to heat the heater υ1111.

In this way, after the ts m tu is turned on, the heater is heated continuously until the surface temperature of the fixing section reaches the heating control start temperature according to the selected heating pattern, and when that temperature is exceeded, the heater is turned off. Pulse 1lil controlled. When the surface temperature of the fixing section reaches a predetermined temperature, the temperature immediately shifts to the steady state, and the predetermined humidity is maintained.

[Embodiment] A fixing device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a schematic diagram showing the main parts of the fixing device of this embodiment.

As shown in FIG. 1, the fixing device of this embodiment includes a fixing roller 2 which is a fixing section having a heater 1, a thermistor 3 which is a fixing section humidity detection sensor that detects the surface temperature of the fixing roller 2, and a power supply. A memory NI 4 stores a plurality of heating patterns for preventing excessive heating and heating the heater 1 to a predetermined temperature in a short time, corresponding to the voltage applied to the heater, and a thermistor 3. A temperature gradient calculation unit 5 that calculates the temperature gradient of the surface temperature of the fixing roller 2 based on the detection signal; a selection unit 6 that selects the optimum heating pattern from the storage unit 4 based on the signal from the temperature gradient calculation unit 5; The heater 1 has a heating blade 7 which heats the heater 1 according to the optimum heating pattern determined.

The heater 1 is a heater that serves as a heat source for heating the fixing roller 2 and melting the toner 10 on the transfer material 9 .

The fixing roller 2 rotates while pressing the pressure roller 8 and the transfer material 10 therebetween.

Since the fixing roller 2 is heated by the built-in heater 1, the fixing roller 2 on the transfer material 10 is heated during pressure contact.
The transfer material 1 is melted while melting the toner 10 attached to the side.
Fixed at 0. The mister 3 detects the surface temperature of the fixing roller 2 by sliding in contact with or in close proximity to the road portion of the fixing roller 2 . This detection of the surface temperature of the fixing roller 2 is always performed after the power is turned on, and is used to adjust the temperature of the fixing roller 2. The storage unit 4 stores heating patterns corresponding to voltages of various power supplies applied to the heater 1. The main heating pattern is to adjust parameters such as duty ratio of 0NOFF pulse control, control start temperature, transition temperature to steady control, etc. to each voltage, and to avoid excessive heating to prevent damage to heaters, etc. It is set to prevent heating (overshoot) and to reach a predetermined temperature in a short time for convenient use. The temperature gradient calculation unit 5 inputs the temperature of the surface of the fixing roller 2 detected by the thermistor 3, and calculates the set temperature T.
The time is measured based on the point in time when the temperature exceeds s, and the other set temperature T
(Measure the elapsed time until 3. In this example, the temperature Ts
is set at 60°C, and the temperature Te is set at 70°C. This calculates the temperature gradient.

The selection unit 6 selects a heating pattern that is most suitable for the temperature gradient determined by the temperature gradient calculation unit 5 from among the plurality of heating patterns stored in the storage unit 4. In this example, 24irI of 100-120■ and 200-2/IOV
There are two types of heating patterns because the power supply voltage of the same type is assumed. The heating pattern of this example is as follows:
It is determined from three types of parameters: heating IM m start temperature, 0N-OFF pulse control control section tee ratio, and steady control transition temperature.

In steady-state control, ON-OFF control is generally performed according to a set temperature range so that the set temperature can be maintained within a certain temperature range. Similar control is performed in this embodiment as well. The heating i control unit 7 includes: a selection unit 6 for power supply to the heater 1;
Heating υ control is performed by adjusting according to the heating pattern selected by .

Next, the control flowchart used in this embodiment will be explained in the second section.
FIG. 3 shows the temperature change of the fixed structure section obtained by the control. The heating pattern used here is when the power supply °M voltage is 100 to 120V band and 200 to 240V band, and the heating pattern is 100 to 12V corresponding to each.
2 for 0V band and 8 for 200-240V band.
Various types are available. At this time, as a heater, 10
Can be used from 0v to 240V, 120v use T-400W
I'm using one.

In this example, the duty ratio of the 0N-OFF pulse υ'' control is the same 2/9 for both A and B, the heating control start temperature is 140℃ for Δ, 80℃ for B, and the steady control transition temperature is AlB.
Both were set at 180°C.

This will be explained according to the flowchart shown in FIG.

At step 100, the power is turned on and the process starts.

The heater 1 generates heat, and the surface temperature (denoted as T) of the fixing row 52 is detected by the thermistor 3. In step 102, it is determined whether the detected temperature of the fixing roller 2 exceeds the temperature Ts (60° C.). If the temperature exceeds Ts, step 1
At 04, time measurement starts at time ts. Fixing row 5
The detected temperature of step 2 further exceeds the temperature T in step 106.
If the temperature exceeds e (70° C.), the time measurement is stopped at time te in step 108. And step 110
, the temperature gradient calculation unit 5 calculates the time (te) required for the detected temperature of the fixing roller 2 to rise from 60°C to 70°C.
−ts) at this time, the temperature gradient r (= (70
-60)/(te-ts)) is calculated. In step 112, the selection unit 6 selects which of the preset heating patterns A and 8 this temperature gradient γ corresponds to. For this selection, the easiest method is to set a discriminant value α1 of the temperature gradient of these two heating patterns A and B, and to select based on the magnitude of the temperature gradient γ obtained here with respect to the discriminant value α1. . If T is smaller than α1, heating pattern A is selected, and if T exceeds α1, heating pattern B is selected.

Each selected person is stored in a predetermined memory on the program in step 114.

The case where heating pattern A is selected will now be described. If the surface temperature T of the fixing roller 2 reaches 140°C in step 116, heating is performed in step 118.
Start FF control. If the heating pattern B is selected in step 116, the process moves to step 118 when the surface temperature T of the fixing roller 2 reaches 80°C. Step 1201. : Power is supplied to the heater 1 by ON-OFF pulse control using a cycle of energization (ON) and m'Fi (OFF). The duty ratio at this time is 2/9. Then, in step 122, it is determined whether the surface temperature of the fixing roller 2 has reached 180.degree. C., and if it has reached 180.degree. C., the routine shifts to steady control in step 124. After shifting to steady-state control, the temperature is maintained at a constant temperature by the normally performed temperature range control.

FIG. 3 shows the transition of the temperature detected on the surface of the fixing row 52 in this embodiment, which is controlled according to the flowchart shown in FIG. 2. In this case, Ca5e works when the voltage of the power supply turned on is 200 to 240V, and CaS
E2 is a case where the same heater is turned on with a voltage of 100 to 120V. The power is turned on at the temperature TO, and the surface temperature of the fixing roller 2 rises almost linearly J.
Ru.

Then, the subsequent temperatures Ts (60°C) and Te (70°C
) is measured, and the temperature gradient γ
is calculated. Therefore, Ca5eI is heating pattern B
However, heating pattern A is selected for Qase[. Therefore, the detected temperature of the surface of the fixing roller 2 is 8.
0℃, Qase [heater 1 until it reaches 140℃
is energized. In this way, the supply to the heater 1 is turned on and off according to the set duty ratio of 2/9.
F is repeated until the predetermined set temperature (180°C) is reached.

Thereafter, the temperature control shifts to steady temperature control, and the normally performed ON-OFF control based on the temperature range is performed.

Furthermore, the storage section 4 of this embodiment can be replaced with a storage section 8 having the following heating pattern. In this heating pattern, among the parameters, the duty ratio of ON-OFF pulse control was set to different values corresponding to two types of power supply voltages. These two heating patterns are A" and B-, and the duty ratio of the 0N-OFF pulse control is 215 for A' and 1/6 for 8'. The heating i'J initial temperature is /M and B- are both set at 100°C, and the steady control transition temperature is set at 180°C for both /MB'.

The flowchart for controlling according to this heating pattern is shown in the fourth section.
FIG. 5 shows the temperature change of the fixing section obtained by υjtll.

Here, the explanation will be given according to the flowchart in FIG. 4. '7! The process from when the power source is turned on and started until the heating pattern is selected is performed in the same manner, so the explanation will be omitted.

From this, heated butter A' is selected and step 21
4, the case where each parameter value is stored in a predetermined memory will be explained. The same applies when heating pattern B' is selected. When the surface temperature T of the fixing roller 2 reaches 100° C. in step 216, heating ON-OFF control is started in step 218. In step 220, power is supplied to the heater 1 at a 0N-OF ratio of 215.
Adjust by F pulse control. If heating pattern B' is selected at this time, the duty ratio is 1/6 (
F) ON OF F i< Ay suaIIJ a
ll k: Naru. At step 222, it is determined whether the surface temperature T of the fixing roller 2 has reached 180° C., and if it has, then at step 224, the process shifts to steady control.

FIG. 5 shows the transition of the temperature detected on the surface of the fixing roller 2 when IIIJ control is performed according to the flowchart in FIG. 4. Ca5eJ is the case when the power supply voltage is 200V, and CaSe'fl is the case when the power supply voltage is <100V.

In this case, in Ca5eI and Ca5e■, the surface temperature of the fixing roller 2 increases almost linearly from the power supply voltage to the same heating control start temperature (100° C.). The elapsed time between the temperature TS (60°C) and the temperature Te (70°C) is measured to calculate the temperature gradient, and the heating pattern A
Select one of the heating patterns B'. In the case of the Ga5e process, heating pattern B' is selected, and the duty ratio of the 0NOFF pulse control is 176. In the case of Ca5e[, heating pattern A' is selected and a duty ratio of 215 is selected. After that, the steady control transition temperature (
When the surface temperature of the fixing roller 2 reaches a temperature of 180° C., steady control is entered, control is performed within a predetermined temperature range, and a constant temperature is maintained.

Note that each parameter of the heating pattern described above may be set in combination. Furthermore, ilJ III parameters other than those used in this example may be used.

In addition, if the surface temperature of the fixing unit is higher than the temperature TS measured to calculate the temperature gradient when the power is turned on, it may take too long to reach a predetermined constant temperature. Therefore, at this time, it is possible to select a prepared heating pattern for the case where the N source voltage is the highest. This is nothing but selecting a highly safe heating pattern to prevent damage to the heater and the fixing unit. In this case, the temperature gradient of the fixing section is m degrees T
It is also possible to wait until the temperature drops below S and then energize the heating heater 1 again to heat the constant η roller 2 to lower the temperature gradient. However, in this method, the time required for the temperature to drop until the surface temperature of the fixing section falls below the temperature TS is generally much longer than for the temperature to rise, so it is not very advisable.

[Effect of the invention 1] In the fixing device of the present invention, a heating pattern for heating the fixing section is prepared in advance in accordance with the applied power supply voltage, and the temperature gradient of the fixing section as the temperature rises after the power is turned on is adjusted. Since the optimum heating pattern is selected from among the heating patterns prepared by , it is possible to perform heating according to the selected heating pattern.

Therefore, excessive heating (overshoot) of the heater and the fixing unit can be prevented, and the temperature can be maintained at a constant temperature that can be used in a short time. This means that the same heater can be used in different regions with different power supplies and voltages. By eliminating the need to set aside heating heaters for different power supply voltages, the associated work and procedures can be omitted, greatly contributing to improved workability and economic efficiency. Further, it is possible to use the device in each region without considering the power supply voltage, and it is possible to continue using the device in the same state. In this manner, the present invention has greatly improved the convenience of the fixing device.

[Brief explanation of the drawing]

FIG. 3 is a flowchart of one sheet of control, and FIG. 3 is a temperature transition diagram of the surface of the fixing roller when controlled as shown in FIG. 2. Fourth
The figure is a flowchart diagram of the control used in another embodiment, and FIG. 5 is a temperature transition diagram of the surface of the fixing roller when the control is performed as shown in FIG. 4.

Claims (1)

[Claims] (1) a fixing section having a heater; a fixing section temperature detection sensor for detecting the temperature of the fixing section; a storage section storing a plurality of heating patterns for heating the fixing section to a predetermined temperature; and the fixing section. a temperature gradient calculation unit that calculates a temperature gradient of the temperature of the fixing unit based on a detection signal from a temperature detection sensor; a selection unit that selects an optimal heating pattern from the storage unit based on a signal from the temperature gradient calculation unit; A fixing device comprising: a heating control section that controls heating of the heater according to the selected optimal heating pattern.