JP2867766B2 - Image heating 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 an image heating and fixing apparatus .

[0002]

2. Description of the Related Art Conventionally, for example, in an image heating and fixing apparatus using a linear heating element having a low heat capacity such as a ceramic heater, the heating element is supplied to an electric heating element in order to keep the temperature of the heating element at a substantially constant predetermined value. In the power control, the detected temperature is compared with a preset temperature, and the supplied power is changed according to the comparison result (Japanese Patent Laid-Open No. 2-259793).
issue). Furthermore, in order to suppress the influence of variation in the resistance value of the heater (heating element), the heater resistance value is made to correspond to a code of a preset resistance value range, and the control group of the supply power is changed according to this code ( Japanese Patent Application No. 2-8016, provisional energization of a heating element, and control of electric power in accordance with a rise in temperature (Japanese Patent Application Laid-Open No. 2-163787).
There was something.

[0003]

However, in the above-described conventional example, it is necessary to measure the heater resistance value and set a code corresponding to the heater resistance value by a dip switch or the like in advance. Alternatively, since a time period for provisional power supply is required, the method is not suitable for application to an image forming apparatus requiring an instant start (quick start property).

Therefore, the present invention provides an electric heating element or a heating element including the same without supplying a predetermined heater resistance value or temporarily energizing the electric heating element to supply a proper electric power to a predetermined temperature of the heating element. An object of the present invention is to provide an image heating and fixing device that can be maintained and controlled to be substantially constant.

[0005]

According to the present invention, there is provided an electric power generating apparatus which is activated by an electric current.
A heating element to be heated and a temperature detecting element for detecting the temperature of the heating element
During the constant temperature control after the heating element has risen to the target temperature,
Heating so that the temperature detected by the temperature sensor maintains the target temperature
Power supply control means for controlling power supply to the body, and a recording material
In the image heating fixing device that heats and fixes the unfixed image on the
The energization control means detects the temperature detected by the temperature detecting element.
The energizing power to the heating element corresponding to
Control group, and the heating element is
After turning on the power to start up to the target temperature,
Until the temperature detected by the temperature detection element reaches the above target temperature
Used during the constant temperature control according to the temperature rise rate detected
Image heating and fixing characterized by selecting a control group
Equipment .

[0006]

<Operation> That is, the present invention measures the rate of temperature change during a preset period after the start of energization of the heating element , and changes the control group of the supplied power according to the measurement result. Without setting the heater resistance in advance and at the start of copying
Thus, it was possible to supply an appropriate electric power without temporarily energizing the image heating / fixing apparatus, and to keep the temperature of the heating body or the image heating / fixing apparatus constant.

[0008]

EXAMPLES <Example 1> (FIGS. 1-5) This embodiment is an image heat fixing equipment for a film heating type using low thermal capacity linear heating member.

(1) Schematic Configuration of Fixing Device (FIG. 1) Reference numeral 5 denotes an endless belt-like fixing film, which is provided with a left driving roller 6, a right driven roller 7, and a lower portion between these rollers 6,7. The low-heat-capacity linear heating element 1 as a heating element fixedly supported and disposed, and the guide roller 6a disposed below the driving roller 6, the four members 6 parallel to each other.
It is stretched between 7.1.6a.

The driven roller 7 also serves as a tension roller for the fixing film 5, and the fixing film 5 has a predetermined peripheral speed in a clockwise direction accompanying the clockwise rotation of the driving roller 6 without wrinkles, meandering, and speed delay. It is driven to rotate.

Reference numeral 8 denotes a pressure roller having a rubber elastic layer having good releasability, such as silicon rubber, as a pressure member, and a lower film portion of the endless belt-shaped fixing film 5 between the heating member 1 and the heating roller 1. And is pressed against the lower surface of the heating element 1 by a biasing means (not shown) with a contact pressure of, for example, a total pressure of 4 to 7 kg, and the transfer material (not shown) from the image forming portion (A) is not shown. The recording material 9 rotates counterclockwise in the forward direction of the conveyance direction.

Since the endless belt-shaped fixing film 5 which is driven to rotate is repeatedly used for heat fixing of a toner image, it is excellent in heat resistance, releasability, and durability.
A thin material having a thickness of 00 μm or less, preferably 40 μm or less is used. For example, polyimide, polyetherimide, P
A single-layer film or a multi-layer film of a heat-resistant resin such as ES / PFA (tetrafluoroethylene-perfluoroalkylvinyl ether copolymer resin), for example, a 20-μm-thick heat-resistant film having PTFE on at least the image contacting surface side.
(Polyfluoroethylene resin) ・ Releasable coating layer with a fluororesin such as PAF and further with a conductive material added to 10 μm
Thick and so on.

The low heat capacity linear heating element 1 as a heating element is
In this example, the fixing film cross direction (fixing film 5
(A direction perpendicular to the running direction of the substrate) is a horizontally long heater substrate 2 and a heating element formed on the surface of the substrate 2 facing the fixing film 5 in a linear or narrow band shape along the length. And a temperature detecting element 4 provided on the heater substrate surface on the opposite side. Reference numeral 1A denotes a heater support that supports the heating element.

The heater support 1A is a member for supporting the heating element 1 in a heat-insulating manner in a fixing device or an image forming apparatus, for example, PPS (polyphenylene sulfide), PAI (polyamide imide), PI (polyimide), and PEEK (polyether). Ether ketone), a high heat-resistant resin such as a liquid crystal polymer, or a composite material of these resins with ceramics, metal, glass, or the like.

The heater substrate 2 has heat resistance and electrical insulation. For example, the heater substrate 2 has a thickness of 1.0 mm and a width of 10 m.
It is an alumina substrate having a length of m and a length of 240 mm. Or a composite substrate including the same.

As an example, the heating element layer 3 is formed by forming Ta on the substantially central portion of the lower surface on the film sliding side of the substrate 2 along the length thereof.
_{This is} a linear or belt-like low-heat-capacity heating element layer formed by coating (screen printing, etc.) an electric resistance material such as 2N-silver-palladium to a width of 1.0 mm, and is energized from both ends in the longitudinal direction. (FIG. 2).

The temperature detecting element 4 is, for example, a thermistor, and is disposed so as to be in contact with the surface of the heater substrate 2 on the side opposite to the side on which the energized heating element layer 3 is provided. In the present embodiment, the temperature of the heater substrate 2 is detected by the temperature detecting element 4 as the temperature of the heater 1.

The transfer material 9 carrying the unfixed toner image 10 on the upper surface, which is conveyed from the image forming section (A) to the fixing device by the image forming apparatus performing an image forming operation in response to the image forming start signal, is guided by a guide. Then, the fixing film 5 enters between the fixing film 5 at the pressure contact portion N (fixing nip portion) between the heating body 1 and the pressing roller 8 and the pressing roller 8, and the unfixed toner image surface has a surface moving state. The sheet passes through the fixing nip N between the heating element 1 and the pressure roller 8 in a state of being overlapped with the movable fixing film 5 without causing any surface shift or wrinkling by being in close contact with the lower surface of the fixing member.

The toner image bearing surface of the transfer material 7 receives the heat of the heating element layer 3 through the fixing film 5 in the process of passing through the fixing nip portion N in a state of being pressed and adhered to the fixing film surface. Melts and softens and adheres to transfer material 9 surface 10a
I do.

In the case of this embodiment, the transfer material 9 is separated from the fixing film 5 when the transfer material 9 passes through the fixing nip N.

The transfer material separated from the fixing film 5 is guided by a guide and solidifies before reaching the paper discharge section, and the transfer material having an image fixed thereon is output.

[0022] (2) power supply to the power supply control heater 1 for heating body (power supply), i.e. the energization of the heat generating layer 3 of the heating body 1 is made from its longitudinal ends as shown in FIG. 2, an AC power source The AC current from the power controller 11 is controlled by, for example, a wave number by a power control element 12 such as a triac. The arithmetic processing unit 13 controls the power control element 12 based on the signal from the temperature detection element 4 as follows.

Now, the target temperature of the fixing device is constant at 165.degree. C., and for the purpose of finely controlling the power at a temperature in the vicinity thereof,
The power supply amount is changed for five stages of temperatures.
The detection temperature is divided into 159 ° C., 163 ° C., 169 ° C., and 177 ° C., and classified into five stages. Power is supplied in accordance with, for example, a group A waveform pattern in FIG. 3 corresponding to the classified temperatures.

Here, the supply waveform to the heating element layer 3 is 7 waves, 6 waves, 5 waves, 4 waves, 3 waves, with a cycle of 20 msec, 8 half waves as a control unit, and a maximum supply amount of 8 waves. Two waves,
The control is divided into nine types of one wave and zero wave, and one control group is controlled by five types of wave numbers. Here, the control groups are divided into three control groups A to C. Then, the control group is determined according to the flow shown in FIG.

The temperature rise rate is defined as the time from 100 ° C. to 150 ° C. First, a control group is provisionally set in advance to, for example, the A group (S1). When the arithmetic processing device 13 starts energization, it sequentially detects the temperature, selects a waveform corresponding to the temperature from the group A, and supplies power. Here, when the initial temperature is 100 ° C. or higher, the process jumps to S8. If the initial temperature is 100 ° C. or lower, the process proceeds to S3 (S2).

When the detected temperature exceeds 100 ° C. (S3),
The timer starts counting up (S4), and stops counting when the temperature exceeds 150 ° C. (S5). Until the temperature exceeds 159 ° C., the maximum supply amount of 8 waves is supplied constantly, and thus the temperature rise rate reflects variations in the heater itself, environmental temperature, and the like.

A control group corresponding to the temperature rise rate is selected according to Table 1 (S6), and after the temperature exceeds 150 ° C., the control group is shifted to the selected control group (S7).

Table 1

[0029]

[Table 1] In FIG. 5, since the temperature rise rate is 1.28 seconds, the control is shifted to the B group. FIG. 5 is a plot of the change over time in the temperature of the fixing device in this embodiment.

In S8, control is performed based on the previous group information, assuming that power has been supplied at least once before this.

<Embodiment 2> (FIGS. 6 and 7) A second embodiment will be described in accordance with the flow chart of FIG.

In this embodiment, the power is subjected to wave number control as in the first embodiment. The rate of temperature rise is defined as the temperature one second after exceeding 100 ° C.

First, a control group is set in advance, for example, to A
A temporary setting is made for the group (S9). Arithmetic processing unit 13
When the power supply is started, the temperature is sequentially detected, and a waveform corresponding to the temperature is selected from the group A and power is supplied. Here, when the initial temperature is 100 ° C. or higher, the process jumps to S16. When the initial temperature is 100 ° C. or lower, the process proceeds to S11 (S10).

When the detected temperature exceeds 100 ° C. (S11)
The timer is started (S12), and the temperature at the time when one second has elapsed (S13) is detected.

A control group corresponding to the temperature rise rate is selected according to Table 2 (S14), and after the temperature exceeds 150 ° C., the control group is shifted to the selected control group (S15).

Table 2

[0037]

[Table 2] In FIG. 7, since the temperature rise rate is 145 ° C., the control is shifted to the B group. FIG. 7 is a plot of the change over time in the temperature of the fixing device in this embodiment.

At S16, control is performed based on the previous group information, assuming that power has already been supplied at least once before this.

<Embodiment 3> (FIG. 8) In this embodiment, the power is controlled in phase. In the same manner as in the above-described embodiment, for example, the phase angle is controlled as shown in FIG.
Then, a control group is selected according to the above-described flow.

[0040]

As described above, according to the present invention, heating
After the power supply to the body is started, the temperature change rate is measured for a preset period, and the control group of the supplied power is changed according to the measurement result, so that the copying can be started again without setting the heater resistance value in advance. Sometimes image heating fixing device
Thus , appropriate power can be supplied without provisional power supply to the heater, and the temperature of the heating element or the image heating / fixing device can be kept constant.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image heating and fixing apparatus according to an embodiment.

FIG. 2 is a block diagram of a power control circuit according to the first and second embodiments.

FIG. 3 is a diagram illustrating selection of a supply power waveform group according to the first and second embodiments.

FIG. 4 is a flowchart of power control in the first embodiment.

FIG. 5 is a graph showing the change over time in the detected temperature in the first embodiment.

FIG. 6 is a flowchart of power control in the second embodiment.

FIG. 7 is a graph showing the change over time in the detected temperature in the second embodiment.

FIG. 8 is a supply power waveform group diagram in the third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating body 2 Heater board 3 Heating element layer 4 Temperature detection element 11 AC power supply 12 Power control element 13 Arithmetic processing unit

Claims (1)

(57) [Claims] 1. A heating element which generates heat when energized, and a heating element
Temperature detection element to detect temperature and heating element to target temperature
During the constant temperature control after startup, the temperature detected by the
Energization that controls energization of the heating element to maintain the target temperature
Control means for heating and fixing an unfixed image on the recording material.
In the above image heating and fixing apparatus, the energization control means controls the temperature detected by the temperature detecting element.
The power supplied to the corresponding heating element is controlled in advance.
Group, and heats the heating element to the target temperature.
Start the energization to start up
Until the temperature of the output element reaches the target temperature.
Control used during the above constant temperature control according to the temperature rise rate issued
Image heating fixing device characterized by selecting a group
Place.