JPS5911112B2 - Temperature control method of heat fixing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temperature control method for a heat fixing device in an information recording device such as a facsimile machine or a copying machine.

First, a temperature control method of a heat fixing device in a conventional information recording device will be explained with reference to FIG.

FIG. 1 is a schematic side sectional view of a heat fixing device in a conventional information recording device.

Toner 8 is adhered to the recording paper 7 by a recording device and a developing device (not shown) in a pre-fixing stage at positions corresponding to characters of the document read by the reading device. However, the adsorption force of this toner 8 to the recording paper T is very weak, and it is necessary to fix it using heat, pressure, etc. in order to obtain a stable received image. A heat source 5 such as a halogen lamp is inserted inside the heat roller 1, and the heat roller 1 is heated by the heat source 5.

6 is a pressure roller for pressing the recording paper T against the heat roller 1, and the recording paper T is moved in the direction of the arrow B by the rotation of the heat roller 1 in the direction of arrow A and the rotation of the pressure roller 6 in the direction of arrow B. It is transported in the C direction.

The recording paper T comes into contact with the heat roller 1 while being conveyed,
The toner 8 adhering thereon is fused to the recording paper T by the heat of the heat roller 1. Incidentally, in such a heat fixing device that uses heat to fix the toner 8 on the recording paper T, it is necessary to control the temperature of the fixing section (corresponding to the heat roller 1). That is, if the surface temperature of the heat roller 1 becomes abnormally high, there is a risk that the recording paper 7 will discolor or burn. Furthermore, if the temperature is too low, the toner 8 cannot be completely fused to the recording paper 7, resulting in poor fixing. Therefore, it is necessary to perform temperature control in order to always maintain the surface temperature of the heat roller 1 at a predetermined fixing temperature. In the case of FIG. 1, this temperature control is performed by the output of a temperature sensing element 3 such as a thermistor attached to a temperature sensing element mount 2 fixed to the housing 9 with screws 4. The temperature sensing element 3
The internal resistance value changes with changes in temperature.
By its output, a temperature control device (not shown) controls the heat source 5
control the power supplied to the However, in the conventional temperature control system of this type, the heat roller 1 has a temperature sensing element mounting base 2.
(i) damage to the surface of the heat roller 1; (11) Since the surface temperature of the heat roller 1 is detected via the temperature sensing element mounting base 2, the response speed of temperature control becomes slow. It had drawbacks such as. The present invention has been made in view of the above-mentioned problems in the prior art, and it detects radiant energy from the surface of a heat roller using an optical system, and controls the temperature of a heat fixing device based on the detected output.

An embodiment of the present invention will be described below with reference to the drawings. Second
The figure is a schematic side sectional view of a heat fixing device according to the present invention. Note that the same numbers as in FIG. 1 indicate the same members.
As in FIG. 1, toner 8 is deposited on the recording paper 7 at positions corresponding to the characters, etc. of the document read by the reading device by a recording device and a developing device (not shown) as a pre-fixing step. There is.

The toner 8 is heated by the heat roller 1 and fused to the recording paper 7. A heat source 5 such as a halogen lamp is inserted inside the heat roller 1, and the heat roller 1 is heated by the heat source 5. By the way, if the temperature of the surface of an object is higher than the absolute temperature, it emits electromagnetic waves to the surrounding area at each temperature.

The radiant energy of this electromagnetic wave has different wavelength ranges depending on the temperature of the object, and varies greatly depending on each wavelength.
This radiant energy follows Planck's law of blackbody radiation, where E(λ, T): radiant energy radiated per unit time from unit area of the surface of the object (J/I・S・μ) λ: blackbody Wavelength (μ) of electromagnetic waves emitted by T: Absolute temperature of black body (KO) C: Radiation constant C2: Radiation constant.

Next, when formula (1) is integrated over all wavelengths, E(b)(T): Radiation energy radiated per unit time from unit area of the surface of the object (J/Wl.S) σ: It becomes the Stephan-Boltzmann constant.

Also, the radiant energy E(λ, T) of a certain object at temperature T
, E(T) can be expressed as the following equation in comparison with the radiant energy of a black body at the same temperature. However, ε is the emissivity.

If the above equations () and () are corrected by multiplying the radiant energy of the black body by the emissivity of the object other than the black body, Planck's law will also apply to objects other than the black body (objects with emissivity less than O). is applied.

Furthermore, since most of the radiant energy emitted from an object is generally infrared rays, in FIG.

Infrared rays 12 extracted by the infrared filter 11 are focused on a detector 14 by an infrared lens 13. When the detector 14 detects the infrared rays 12, it outputs a signal to the amplifier 15, and the temperature control circuit 16, which receives the signal amplified by the amplifier 15, performs temperature control to be described later. It will be done. That is, by focusing on the fact that the radiant energy 10 from an object is determined by its wavelength and temperature from the above equation (1), a specific wavelength (wavelength at a certain temperature) of the radiant energy 10 is detected by the photoelectric effect/current conversion type detector 14. By detecting this, the surface temperature of the object can be detected. In addition, by noting that the total amount of radiant energy is proportional to the fourth power of the absolute temperature from the above formula (), by detecting the total amount of radiant energy over all wavelengths with the thermoelectric detector 14, the surface temperature of the object can be measured. can also be detected. By using either one of the two detectors 14 described above, the surface temperature of the heat roller 1 can be detected.
A corresponding signal is input to the temperature control circuit 16.
The temperature control circuit 16 compares a predetermined fixing temperature with the input surface temperature of the heat roller 1. As a result of this comparison, if the surface temperature of the heat roller 1 is higher, the power supplied to the heat source 5 is set to 60FF, and control is performed so that the surface temperature of the heat roller 1 does not rise any higher. Conversely, when the fixing temperature is higher, power is continuously supplied to the heat source 5. By performing the temperature control as described above, the surface temperature of the heat roller 1 is maintained at the fixing temperature. In addition, the temperature control circuit 16 also performs functions such as abnormal high temperature control (control to stop the apparatus when the surface temperature of the heat roller 1 becomes higher than a predetermined temperature higher than the fixing temperature). It may be equipped. As described above, according to the present invention, the surface temperature of the heat roller is detected from the radiant energy emitted from the surface of the heat roller.
There is no damage to the surface of the heat roller, and there is no need for a temperature sensing element mounting stand or the like as in the conventional case, so the response speed of temperature control becomes faster.

[Brief explanation of the drawing]

FIG. 1 is a schematic side sectional view of a heat fixing device in a conventional information recording device, and FIG. 2 is a schematic side sectional view of a heat fixing device according to the present invention. 1...Heat roller, 5...Heat source, 6
...Pressure roller, 7...Recording paper, 8.
...Toner, 10...Radiant energy,
11...Infrared filter, 12...Infrared rays, 13...Infrared lens, 14...
Detector, 15...Amplifier, 16...Temperature control circuit.

Claims (1)

[Claims] 1 The wavelength of the radiant energy emitted from the surface of the heat fixing device is detected by a photoelectric effect/current conversion type detector through an optical system consisting of an infrared filter and an infrared lens, and this photoelectric effect is detected by a photoelectric effect/current conversion type detector. - A temperature control method for the heating and fixing device in which the temperature of the heating and fixing device is controlled by the output of a current conversion type detector.