JPH0310275A - Fixing device - Google Patents

Abstract

PURPOSE:To obtain stable fixation by providing a control means which controls the rotation of a pair of warming-up rotors in response to the temperature of other states of the pair of the rotors. CONSTITUTION:The outer surface temperature (TU) of a fixing roller 1 is detected by a temperature sensor 51 and inputted to a detecting circuit 61. In response to an obtained value, a heater control circuit 62 controls the on-off operation of a heater 3. The outputted value of a temperature sensor 52 which measures atmosphere temperature (TE) is inputted to the detecting circuit 61 and the values of TF and TE are inputted to an operating circuit 63. While, a value outputted based on such an operation result as that a time accumulated value (H) since a main body power source is turned on is inputted from a main control circuit 64 to the operating circuit 63 is inputted to a fixing roller driving circuit 65 and controls a fixing roller driving motor 7. Thus, fixation is stabi lized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fixing device used in a copying machine or a racer heel printer, and particularly to a fixing device that rotates a pair of rotating bodies during warm-up of the device.

(Prior art) Conventionally, this type of fixing device consists of a fixing roller and a pressure roller. Generally, the temperature of the fixing roller is detected by a temperature sensing element such as a thermistor, and the heater etc. is turned on after a preset temperature level is reached. It was controlling the heater to the heat source.

Further, immediately after the fixing roller reaches the set temperature at which warm-up ends after the power is turned on, the pressure roller is not sufficiently heated, resulting in a disadvantage that the fixing ability is reduced.

For this reason, the roller pair is rotated during warm-up to heat the pressure roller (hereinafter referred to as multiple rotations).

Previously, the multiple rotations were generally performed depending on the surface temperature of the fixing roller.

However, since the fixing ability depends on the temperature, moisture content, etc. of the recording paper passing through the fixing device, stable fixing ability cannot be obtained with the above conventional setting method.

Furthermore, uniformly performing multiple forward rotations even when the pressure roller is sufficiently heated, such as when the operation of the copying machine is interrupted due to a jam during copying, will delay the time it takes to start copying after printing. There was this inconvenience.

Furthermore, it has been known empirically that even if the temperature of the fixing roller has reached the set value, there is a difference in fixing ability depending on the temperature of the pressure roller and the temperature of the transfer paper, but these state quantities and control It was difficult to formulate the relationship between quantities.

(Means for Solving the Problems) The present invention for solving the above problems is a fixing system in which a support material supporting a toner image is held and conveyed between a pair of rotating bodies, at least one of which is heated by a heat source, and a toner image is fixed. A fixing device that rotates a pair of rotary bodies during warm-up, the fixing device comprising: a control means for controlling the rotation of the pair of rotors during warm-up according to the temperature and other conditions of the pair of rotors; and a fixing device which fixes a toner image by sandwiching and conveying a support material supporting the toner image between a pair of rotating bodies, at least one of which is heated by a heat source, the fixing device having a warm-up The fixing device rotates a pair of rotating bodies inside the fixing device, and is characterized by comprising a control means for controlling the rotation of the pair of rotating bodies during warm-up based on an inference value obtained using a fuzzy set.

(Embodiment) FIG. 1 shows a fixing device according to an embodiment of the present invention. 1 is a fixing roller that rotates in the direction of the arrow. The fixing roller 1 has a core metal 11
A release layer 12 (generally made of silicone rubber or fluororesin) is provided on the outer layer of the mold (generally made of a metal material such as aluminum or stainless steel). There is a heater 3 inside the fixing roller 1, which heats the surface of the fixing roller 1 to a desired set temperature.

The pressure roller 2 rotates in the direction of the arrow, and has an elastic layer 22 (made of a silicone rubber layer, a fluororesin layer, etc.) on the outer layer of a core metal 21 (the aforementioned metal). The recording paper 4 supporting the toner image advances in the direction of the arrow, and is heated and pressed by the fixing roller 1 and the pressure roller 2 to be fixed. The temperature (Tu) of the outer surface of the fixing roller 1 is detected by a temperature sensor 51 (generally using a thermistor) and input to a detection circuit 61 .

Depending on this value, the heater control circuit 62 turns on the heater 3.
-Control off. Further, the output value from the temperature sensor 52 that measures the ambient temperature (T) is similarly input to the detection circuit 61. Furthermore, the values of TF and TE are input to the arithmetic circuit 63.

On the other hand, the state of the main body, that is, the time cumulative value (H) since the power of the main body was turned on, is input from the main body control circuit 64 to the calculation circuit 63. A value outputted based on the calculation result is sent to the fixing roller drive circuit 65. It is input and controls the fixing roller drive motor 7.

The above is the flow for pre-multi-rotation control, but regarding the copying operation, although not shown, the fixing roller drive circuit 65 controls the fixing roller drive motor 7 based on a signal from the main body control circuit 64.

The calculation contents of the calculation circuit 63 will be described regarding the pre-multi-rotation control. Operations are based on fuzzy operations. Ambient temperature (TE) and main body power-on time (H) are used as state quantities. The fixing roller surface temperature (Tu) is used as the control amount. 'F
U means the pre-multi-rotation starting temperature. FIG. 2 shows fuzzy sets called membership functions of state quantities and control quantities. (a), (b) are state quantities, (C) is control ■
It is. The meanings of the symbols are: TE1 is 15°C or less, T, 2 is around 15°C, T, 3 is around 25°C, TE4 is around 35°C, TE5 is 35°C or more.2, Hl is 2 hours or less, H2 is Around 2 hours, H3 more than 2 hours, Tul 140'
Below C, TU2 is around 140°C, TiI4 is 150°C
Before and after, TU4 shows around 160°C, and TU5 shows 1600°C or more.

When the ambient temperature is 25°C, the degree to which it belongs to the set TE3 is 1.0, and at 20°C, the degree to which it belongs to TE3 is 0.5, and the degree to which it belongs to T,2 is 0.5. .

Next, the fuzzy rules are shown in Table 1.

An example of calculating the pre-multi-rotation start temperature using this rule will be shown below.

Assuming that the ambient temperature TE is 20° C. and the power-on time 1-1 is 1 hour, the sets included in T, -2000 are TE2 and TI:3 according to the 2-note rule. Also, the sets included in H=1 hour are Hl and T-T2. Therefore, the rule is: ■ TE =TE 2 and H=H1->Tu
=TU 1■ TE=T, 2 and H=H2→
TU=Tu2■ TE :TE 3 and H:
H] → TU = TU 2 ■ Go E = T
E 3 and H=H2→ T
These relationships, which hold that u = TU 3, are shown in FIG.

Figure 3 ■ corresponds to rule ■.

The value belonging to the TE2 set corresponding to 20℃ is 0.5.1
The value belonging to the set of Hl corresponding to time is 0.5, and the minimum value of both is 0.5, so the portion corresponding to 0.5 of the set of TUl is S. (2) similarly corresponds to the rule (2), and 82 is obtained in the portion corresponding to TE2.

Furthermore, although not shown, if ■ and ■ are processed in the same way, S
3. A portion S4 is obtained. The sum of these parts becomes area S in FIG. In Fig. 4, the center of gravity of S is found to be TU - about 142°C.

Therefore, in this example, the fixing roller surface temperature TU is 142
Arithmetic processing is performed to start multiple rotations when the temperature reaches °C. As another example, if the ambient temperature TE is 3000 and the power-on time is 3 hours, the pre-multiple rotation start temperature is TU=
It becomes 158°C.

In other words, the lower the ambient temperature T0 and the shorter the power-on time H, the lower the pre-multi-rotation start temperature, and the more heat is transferred to the pressure roller, thereby stabilizing the fixing performance. I'm trying.

Note that the outside air temperature is used as a substitute characteristic for the temperature of the transfer paper, and if the temperature of the transfer paper is low, a large amount of heat will be taken away by the transfer paper. Therefore, it is necessary to store a large amount of heat in the pressure roller in advance. In addition, if the power is turned on for a short time, the amount of heat from the heater and the fixing roller are not sufficiently conducted to the fixing device, so the temperature of the entire device does not rise and the temperature of the fixing roller decreases. Even if the pressure itself is a constant value, the amount of heat is taken away by heating the device in addition to heating the transfer paper, so it is necessary to store the amount of heat in the pressure roller.

Next, another embodiment of the present invention will be shown.

FIG. 5 shows an embodiment in which front multiple rotation control is performed using an ambient temperature sensor 52 and a pressure roller surface temperature sensor 53.

Ambient temperature (T1) and pressure roller surface temperature (TL) are used as state quantities, and fixing roller surface temperature (T
Let U) be the pre-multi-rotation starting temperature.

These fuzzy sets are not shown in Figure 6. (a) and (c)
is equivalent to the above, or (b) is TL] is 100'C
Below, TL2 is around 100°C and TL3 is over 1ooOC. These are calculated using the fuzzy rules shown in Table 2.

It detects the same thing as the male side.

However, the rotational speed of the fixing roller drive motor 7 is controlled as the control amount. FIG. 7(c) shows the pre-multiple rotational speed as a percentage when the rotational speed of the fixing roller during copying operation is 100, where R1 is 70% or less, R2 is around 70%, and R3 is a membership function that indicates approximately 80%, R4 indicates approximately 90%, and R5 indicates 90% or more. Table 3 shows the fuzzy rules.

In this embodiment, when the surface temperature (TL) of the pressure roller is low, the previous multiple rotation start temperature is set as the fixing roller temperature (Tu).
Starting from a low temperature, a sufficient amount of heat is applied to the pressure roller.

Next, another embodiment of the present invention will be described.

In this embodiment, the state quantity is the second value mentioned above.When the pressure roller temperature TL is low, the fixing roller rotation speed during the previous multiple rotations is slowed down, and the purpose is to sufficiently raise the temperature of the pressure roller. This was done as a.

(Effect) As described above, in stabilizing the fixing ability of a fixing device for copy paper, etc., where the relationship between the state quantity and the control amount is ambiguous, the control amount can be It became possible to calculate. In particular, it has become possible to control the break-in rotation of the fixing roller pair prior to the copying operation, for example, the pre-multi-rotation start temperature or the pre-multi-rotation speed, in accordance with the state quantity of the apparatus.

These controls are determined by a combination of complex state quantities, and use fuzzy theory membership functions. As a result, fuzzy calculations can be easily performed, the effort of complicated programming can be saved, and the increase in memory elements, etc. that are useless during programming can be prevented, and ambiguous device status can be numerically controlled. .

[Brief explanation of drawings]

. FIG. 1 is a sectional view showing a fixing device according to an embodiment of the present invention, FIG. 2 is a diagram showing a membership function used in an embodiment of the present invention, and FIGS. 3 and 4 are diagrams showing a method of fuzzy calculation. Figure, 5th
The figure is a sectional view showing a fixing device according to another embodiment of the present invention. Figures 6(a') to (C) are diagrams showing another membership function of the present invention. ) is a diagram showing yet another membership function of the present invention. In the figure, ■... Fixing roller 2... Pressure roller 3... Heater 4... Recording paper 51, 52. 53...Temperature sensor 61, 62
．． 63. 64. 65...Each circuit 7...Fusing roller drive motor

Claims (5)

[Claims] (1) A fixing device that fixes a toner image by sandwiching and conveying a support material supporting a toner image between a pair of rotating bodies, at least one of which is heated by a heat source, and the pair of rotating bodies is rotated during warm-up. A fixing device comprising: a control means for controlling rotation of the pair of rotors during warm-up according to the temperature and other conditions of the pair of rotors. (2) A fixing device that fixes a toner image by sandwiching and conveying a support material supporting a toner image between a pair of rotating bodies, at least one of which is heated by a heat source, and the pair of rotating bodies is rotated during warm-up. What is claimed is: 1. A fixing device comprising: a control means for controlling the rotation of the pair of rotating bodies during warm-up based on an inference value obtained using a fuzzy set. (3) The control means controls at least one of rotation start timing, rotation stop timing, and rotation speed of the pair of rotating bodies during warm-up.
The fixing device according to item 1 or 2. (4) The above device further includes a detection means for detecting a state quantity of the device in order to obtain an inferred value, and the detection means detects at least one of the rotating body temperature, the ambient temperature, the device surrounding temperature, and the time after the start of warm-up. The fixing device according to claim 2, wherein the fixing device detects. (5) Claims 1 or 3 characterized in that the lower the temperature or the shorter the time after power-on, the lower the rotation start temperature or the slower the rotation speed during warm-up. The fixing device described.