JPH05289562A - Heating device - Google Patents

Abstract

PURPOSE:To secure good image fixation when a heating device functions is an image heating and fixing device by setting a time for stopping, or reducing the heat generation of a heating body in the case that a material to be heated is not positioned at a heating body position and varying the time. CONSTITUTION:The output signal of a temperature detecting member (thermistor) 8 is inputted to a CPU 32 through an A/D converter 31. The power which is supplied from a power source 20 to an electro-thermal body 4 is controlled by the CPU 32 through an AC driver 33 based on the input signal. The temperature is controlled so that the temperature may be 180 deg.C on the surface of the heating body 2 when the paper is in passing. Then, at a non-paper passing time such as an interrupted interval time between the papers as the body to be heated continuously passing, a no-energizing state where the heating body 2 is not energized is attained, and no-energizing time is varied in accordance with information such as a paper continuously passing time, an input power required to maintain the conditioning temperature, the temperature drop speed of the heating body 2 after stopping the energization of the heating body 2, and the signal of the size of the body to be heated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a heat-resistant film which is brought into contact with and slid on a heating body, and a material to be heated is brought into close contact with the surface of the film opposite to the heating body, and the film passes through the position of the heating body together with the film. The present invention relates to a film heating type heating device which applies heat energy from a heating body to a material to be heated through the film.

Further, the present invention relates to a heating device having a heating body and a temperature detecting member for detecting the temperature of the heating body, and energizing the heating body so that the temperature detected by the temperature detecting member is kept constant at a predetermined temperature.

[0003]

2. Description of the Related Art The above-described film heating type heating device is known from Japanese Patent Application Laid-Open No. 63-313182 and Japanese Patent Application Laid-Open No. 2-157878 related to the applicant's earlier proposal. An image heating fixing device in an image forming apparatus such as a copying machine, a printer or a fax machine, that is, a developer (toner) made of a heat-fusible resin or the like is used by an image forming process means such as electrophotography, electrostatic recording or magnetic recording. Recording material (electrofax sheet, electrostatic recording sheet, transfer material sheet,
An unfixed developer image corresponding to the target image information formed by a direct method or an indirect (transfer) method on the surface of printing paper) is heat-fixed as a fixed image on the recording material carrying the image. It can be used as an image heating and fixing device.

Further, it can be used, for example, as an apparatus for heating a recording material carrying an image to modify the surface properties of gloss and the like, an apparatus for post-process adhesion, and the like.

More specifically, a thin heat-resistant film (sheet), a driving means for moving the film, and a heating element (heater) arranged to be fixedly supported on one side of the film with the film inside. And a pressing member disposed on the other surface side so as to be opposed to the heating body and closely contacting the developer image carrying surface of the recording material to be image-fixed to the heating body via the film, At least during image fixing, the film is moved at the same speed in the forward direction as the recording material to be image-fixed, which is conveyed and introduced between the film and the pressure member, and the moving member is sandwiched between the film and the heating member. By passing through a fixing nip portion as a fixing portion formed by pressure contact with a pressure member, the developer image carrying surface of the recording material is heated by the heating body through the film to form an unfixed developer image. Thermal energy is applied to the (unfixed toner image) to soften it. · Allowed melt, then an image heating fixing apparatus of film heating type which is based on that to separate the recording material and the film after fixing portion passing through at the separation point.

FIG. 31 shows a schematic configuration of a specific example thereof. FIG. 32 is a plan view of the heating element with a part of the heating element omitted and a block diagram of the energization control system.

Reference numeral 1 denotes a heat-resistant film (fixing film) in the form of an endless belt, which is a driving roller 11 and a driven roller 1 which also serve as tension rollers and are arranged substantially parallel to each other.
2 and three members of the heating body (heater) 2 are suspended and stretched.

The film 1 has a total thickness of 100 μm or less, preferably 40 μm or less and 20 μm or more in order to reduce the heat capacity and improve the quick start property. Heat resistance, releasability, strength, durability, etc. PTFE with
It is a single layer film such as PFA or PPS, or a composite layer film obtained by coating the surface of a film such as polyimide, polyamideimide, PEEK or PES with PTFE, PFA or FEP as a release layer.

Numeral 13 is a heater holder that adiabatically supports the heating element 2, and 10 is a heating element 2 sandwiching the film 1 between the heating element 2 and the surface of the heating element 2 to press the film at a total pressure of 4 to 15 kg. The pressure roller has a rubber elastic layer having good moldability.

By rotating the driving roller 11, the film 1 is brought into close contact with the surface of the heating body 2 in the clockwise direction indicated by the arrow at least when the image is fixed, and slides on the surface of the heating body at a predetermined peripheral speed, that is, not shown. The recording material P, which carries the unfixed toner image T conveyed from the image forming section (A) side, is rotationally driven without wrinkles at substantially the same peripheral speed as the conveying speed.

The heating element 2 includes an energization heating element (resistive heating element) 4 as a heat source that generates heat by supplying electric power, as will be described later, and the heating of the energization heating element 4 raises the temperature.

In a state where the heating element 2 is heated by the power supply to the energization heating element 4 and the film 1 is rotationally driven, the pressure contact portion N between the heating element 2 and the pressure roller 10 is applied.
By introducing the recording material P between the film 1 and the pressure roller 10 in the (fixing nip portion), the recording material P comes into close contact with the film 1 and overlaps with the film, and the fixing nip portion N Going through.

In the course of passing the recording material P through the fixing nip portion, heat energy is applied to the recording material P from the heating body 2 through the film 1, and the unfixed toner image T on the recording material P is heated and melted and fixed. After passing through the fixing nip portion, the recording material P is separated from the film 1 and discharged.

The heating element 2 of the present example comprises: a. An elongated ceramic substrate 3 having electrical insulation, heat resistance, and low heat capacity, such as Al ₂ O ₃ (alumina), AlN, or SiC, whose longitudinal direction is substantially orthogonal to the moving direction of the film 1.
And b. The substrate 3 is formed in a linear shape or a strip shape along the length of the substrate in the central portion of the one surface side (front surface side) in the substrate width direction,
Silver palladium (Ag / Pd), RuO as a heat source
An energization heating element 4 such as ₂ , ₂ , Ta ₂ N, and c. Power supply electrodes 5 and 6 formed on the substrate surface so as to be electrically connected to both ends of the energization heating element 4, respectively. D. An electrically insulating overcoat layer 7 made of glass or the like as a surface protective layer covering the surface of the substrate 3 on which the electric heating element is formed, and e. It comprises a temperature detecting member 8 such as a thermistor provided in contact with the other surface side (back surface side) of the substrate 3, a temperature fuse 9 serving as a temperature detecting element (thermal protector) for safety measures, and the like.

The overcoat layer 7 side of the heating element 2 is the film contact sliding surface side, and this surface side is exposed to the outside, and the heating element 2 is fixedly supported on a support portion (not shown) via a heat insulating heater holder 13. I am allowed to do it.

The heating element 2 is a power supply electrode 5 on both ends of the electric heating element 4.
A voltage is applied from the AC power supply 20 between 6 and the energization heat generating body 4 generates heat to raise the temperature.

The temperature of the heating element 2 is detected by the temperature detecting member 8 on the back surface of the substrate, and the detected information is fed back to the energization control circuit 15 to control the energization from the AC power source 20 to the energization heating element 4 to fix the fixing element. Temperature control is performed so that the temperature of the heating element 2 detected by the temperature detection member 8 at the time of execution becomes a predetermined temperature (fixing temperature).

The temperature control of the heating element 2 is carried out by controlling the applied voltage or current to the energization heating element 4 or by controlling the energization time. Methods for controlling the energization time include zero-cross wave number control for controlling energization and non-energization for each half-wave of the power supply waveform, and phase control for controlling a phase angle energization for each half-wave of the power supply waveform.

That is, the output of the temperature detecting member 8 is A / D exchanged and fetched into the CPU, and based on the information, the AC voltage applied to the energizing heating element 4 is subjected to pulse width modulation such as phase control or wave number control by a triac. The energization of the energizing heating element 4 is controlled so that the temperature detected by the heating temperature detecting member 8 is constant.

The temperature detecting member is a recording material as a material to be heated, regardless of the size of the recording material.
The paper passing portion of the heating element is always arranged at a position corresponding to the paper passing area so as to maintain a constant temperature.

The thermal fuse 9 is connected in series to the energization path for the energization heating element 4 and is arranged in contact with the back surface of the substrate 3 of the heating element 2, so that the energization control of the energization heating element 4 is impossible. When this occurs and the temperature of the heating element 2 rises abnormally (runaway of the heating element), the thermal fuse 9 operates to open the energizing circuit to the energizing heating element 4 and turn off the energization to the energizing heating element.

The film heating type apparatus as described above is
Since the heating element 2 having a body heat capacity can be used, the weight time can be shortened (quick start property) as compared with the conventional heating device such as the heat roller system, and the quick start can be performed. Preheating when not in use is no longer necessary, and power saving can be achieved in a comprehensive sense. In addition, it has an advantage that it can solve various drawbacks of other heating type devices, and is effective.

FIG. 33 shows another image heating fixing apparatus of the film heating type. In this device, the heating element 2 is fitted into a heating element accommodating recess formed in the central portion of the outer surface of a semi-circular film guide member (stee) 14, and the cylindrical heat-resistant film 1 is removed from the film guiding element 14. The pressure roller 10 is pressed against the heating body 2 with the film 1 sandwiched between the heating body 2 and the heating body 2.

The inner peripheral length of the endless film 1 and the outer peripheral length of the film guide member 14 including the heating body 2 are the same.
Is larger by, for example, about 3 mm, so that the film 1 is loosely fitted on the film guide member 14 including the heating body 2 with a sufficient peripheral length.

By rotating the pressure roller 10 as a driving roller in the counterclockwise direction as indicated by the arrow, the cylindrical film 1 is rotationally driven by the frictional force with the roller while closely contacting the surface of the heating body 2 and sliding. It

Also in the case of this apparatus, the heating body 2 and the pressure roller 1
The recording material P is introduced between the film 1 and the pressure roller 10 in the fixing nip portion N with the heating member 2 by passing the recording material P therethrough.
Thermal energy is applied to the recording material P from the film 1 through the film 1, and the unfixed toner image T on the recording material P is heated and fused and fixed. The structure and energization control of the heating element 2 are the same as those in FIGS. 31 and 32.

The film 1 may be a roll-wound lengthy film, and the film may be paid out and run in close contact with the surface of the heating body 2.

[0028]

The heating device of the above example has the following problems.

(A) As described above, the temperature detecting member 8 of the heating element 2 always corresponds to the paper passing area regardless of the size of the recording material (paper) as the material to be heated. Since the energization heating element 4 of the heating element 2 is energized so that the temperature detected by the heating element is always controlled to be constant at a position, small-sized paper such as B5 paper, envelopes, and postcards is continuously passed. When paper is printed, there is a temperature difference of 8
It becomes 0 deg or more (non-sheet passing area overheating phenomenon of heating element).

Therefore, the pressure roller 10 as a pressure member
The difference in outer diameter between the paper-passing area and the non-paper-passing area due to thermal expansion becomes several hundreds of μm. There was a problem that occurs.

If such a state is continued for a long time,
There is a problem in that the pressure roller 10 and the film 1 are thermally deteriorated, the life of parts is shortened, and in the worst case, the device is damaged.

As a method of solving this problem, a method of providing a plurality of heating patterns (heating element patterns) of the heating element and energizing only that area in accordance with the size of the recording material to be fed may be considered. There is a drawback that the method becomes complicated and the cost increases.

A fixed time (generally 2 to 3 seconds) is provided between recording materials that are continuously fed (between recording materials).
Another possible method is to reduce the temperature of the non-sheet passing area of the heating element by making the heating element non-conducting state.

However, since the heating element 2 of this type of heating device has a very small heat capacity, if the contact parts such as the pressure roller 10 are cold, the heat will immediately escape from the heating element 2. On the other hand, if it is warmed up, the escape of heat from the heating element 2 will be small. Therefore, the speed of the decrease in the surface temperature of the heating element 2 will be extremely different between these two, and for example, in the case of a system in which it is de-energized for a certain period of time, If the non-energization time of the paper interval (paper interval of 3 sec) is determined to be about 0.5 sec when the temperature is cold, there is a drawback that the effect of lowering the temperature of the non-paper passing region of the heating element is reduced. On the contrary, if the non-energization time between papers of 2.5 seconds is determined when the apparatus is warmed up, the temperature required for fixing does not rise for the second and third sheets during continuous paper feeding. Therefore, there is a drawback that an image with poor fixing is obtained.

The present invention suppresses the above-mentioned problem, that is, the excessive temperature rise phenomenon of the non-sheet passing area of the heating body during the continuous sheet passing of the small-sized material to be heated, and the image heating fixing device as the heating device cools down. The purpose is to ensure good image fixability even in the presence of the state.

(B) FIG. 34 shows the temperature of the heating element during printing,
It is a schematic diagram which shows the time change of a film temperature and a pressure roller surface temperature.

The heating element 21 is heated to 200 ° C. at the start of printing.
The temperature is adjusted to a certain level. On the other hand, since the pressure roller 10 has a large heat capacity, the surface temperature gradually rises. At this time, the film temperature also gradually rises while taking an intermediate value between the temperature of the heating body and the surface temperature of the pressure roller, and the change amount is the same as that of the first sheet of paper which is heat-transferred to the pressure roller and other parts. 50-60 deg with the 8th sheet of paper that has accumulated
It makes a difference.

When the film temperature is lower than β ° C., fixing failure occurs, and when it is higher than α ° C., high temperature offset occurs.

When there is such a temperature difference between the films, α and β (generally about 30) which can achieve both fixing failure and high temperature offset (transfer of the developer to the film) depending on the film temperature.
It is difficult to insert the sheet in all the sheet-passing modes (eg, the first sheet in the low-temperature environment and the 50th sheet in the continuous sheet-passing) during the deg). Therefore, the timing to forcibly de-energize the heating element or the timing to supply constant power to the heating element is set between the sheets, and the temperature control temperature of the heating element surface is changed based on this temperature change, and the film temperature is kept constant in any mode. Both the fixing failure and the high-temperature offset are achieved by using the control method described above.

However, since the heating body non-energization time and the heating body temperature lowering time for determining the next heating body temperature control temperature are the same, the heating body non-energization time becomes shorter for some reason. If it happens, for example, 0.5 sec
When observing the descending speed afterwards, the temperature on the surface of the heating body has a small heat capacity, so that the temperature rises greatly even in a short time and shows a movement as shown in FIG. 35. There is a possibility that the temperature adjustment temperature is lowered and a defective fixing image is generated.

Further, a temperature control mode (low temperature control between sheets) is provided between the sheets, and the temperature is set for a predetermined time (0.5 sec).
Even when the next temperature is determined depending on whether or not the temperature falls to c), a temperature ripple is generated on the heating body even though the inter-paper low temperature control is performed by 0.5 seconds as shown in FIG. Therefore, after 0.5 sec, it is determined that the temperature is higher than the temperature control temperature and the entire apparatus is warmed up, and the heating body temperature control temperature is lowered, and there is a possibility that a defective fixing image is output as described above.

When the pressure roller 10 is cold, FIG.
As described above, the temperature of the heating element may be too low to sufficiently increase for the next paper.

When the heating member temperature is set so that the film temperature becomes β ° C. (FIG. 34) or more in the first sheet of paper to prevent the fixing failure, the apparatus becomes warm and the temperature becomes high after the seventh sheet of paper is passed. If the temperature of the heating element is lowered in order to prevent the high temperature offset after the seventh sheet of paper passing after the offset occurs, fixing failure occurs in the first sheet of the paper that is cold in the apparatus.

In order to solve this problem, it has been conventionally proposed to lower the temperature of the heating body according to the number of prints during continuous printing, but even in this case, the film temperature is kept constant depending on how warm the apparatus is. Since the appropriate value of the heating body temperature of the first sheet to be passed and the number of sheets for lowering the heating body temperature are different, it is necessary to change the operation depending on each case, and the control becomes complicated.

For example, when 10 sheets are continuously fed at 2-minute intervals, or when sheets are passed at 3-minute intervals and 10-minute intervals, there are an infinite number of combinations of 5 sheets, 50 sheets, and so on. It is almost impossible to control the temperature of the heating element considering the case.

The present invention eliminates the above-mentioned problem, that is, the erroneous detection of the control for the temperature change of the heating body, and the film temperature can be kept constant regardless of the mode in which the apparatus is used. It is an object of the present invention to prevent fixing failure and high temperature offset of the image heating and fixing device.

(C) In the film heating type heating device, since the heat capacity of the heating element 2 is small, if the temperature of the heating element is controlled by simply turning on / off the electricity to the energization heating element 4, the temperature ripple of the heating element will occur. Undesirably increases.

Therefore, conventionally, control has been carried out in which power is supplied to the heating element in detail by phase control, wave number control, or the like, and the power that is almost optimal for maintaining the heating element at a predetermined temperature is constantly supplied.

Here, the wave number control means that the AC voltage applied to the heating body is set at a specific wave number (hereinafter referred to as a fundamental wave number).
Neglect, turn on some of the waves (energize), and the rest O
This is a method of finely controlling the amount of power supply by performing FF (non-energization).

In this control, ON / OFF is performed within the fundamental wave number.
A small temperature ripple (called wave number ripple) is possible.

To reduce this wave number ripple, O
There is also a method to disperse N waves almost uniformly in the fundamental wave number, but if this is done, the number of ON / OFF increases, so
Frequent load fluctuations on the power supply side cause image shrinks of CRTs used nearby and flicker of fluorescent lamps.

For this reason, a method is generally used in which the ON wave and the OFF wave are combined within the fundamental wave number.

Also, when the temperature of the heating element is raised to a predetermined temperature, the rate of temperature rise is detected, and various control values (for example, temperature control temperature, power supply, etc.) after the temperature rises according to the rate are detected.
A control method for determining is also devised.

The combination of these control methods is very effective because the temperature of the heating element can be controlled more finely and accurately.

However, when the heating rate is detected in a system for raising the temperature of the heating element to a predetermined temperature while controlling the amount of electric power by controlling the wave number, if the rate is detected in a short time, the heating element is heated. There was a problem that the speed could not be detected accurately.

FIG. 38 is a temperature rise curve of the heating body showing this. This is AC of f-50Hz, _Vac- 115V
When the basic wave number of wave number control with voltage is 20 waves, 10 waves-
The figure shows two cases in which the temperature of the heating element is raised under the conditions of ON, 10 waves-OFF, and the heating rate is measured within 50 msec after the heating element temperature reaches 140 ° C.

When the wave number control is used, a wave number ripple as shown in FIG. 38 can be generated even when the temperature of the heating element rises.

Therefore, even if the speeds are measured under the same conditions and the same speeds are naturally required to be detected, the speeds will be significantly different depending on the detected points. For example, in (a) of FIG. 38, the temperature rise rate is measured only when electricity is applied, and thus it is 150 deg / sec, whereas in (b) most of the measurement time is when electricity is not applied, The temperature rate is 5 deg / sec.

As described above, even if the speed is detected at the same timing and at the same detection time, if the detected values have the above variations, the control value cannot be accurately determined thereafter.
The temperature of the heating element cannot be adjusted to the desired temperature.

The present invention relates to a heating device for detecting the temperature rising rate when raising the temperature of a heating element to a predetermined temperature with the electric power controlled by the wave number control, and determining various control values thereafter according to the rate. , Reduce the error in speed detection,
It is an object of the present invention to make it possible to more accurately perform control after rising.

[0061]

The present invention is a heating device characterized by the following constitutions.

(1) A heat-resistant film is brought into contact with and slid on the heating body, a material to be heated is brought into close contact with the surface of the film opposite to the heating body, and the film is passed together with the film through the position of the heating body. In a heating device for applying heat energy to a material to be heated through the film, when the material to be heated does not exist at the position of the heating body, a time for stopping or reducing heat generation of the heating body is provided, and this time is variable. A heating device characterized by.

(2) When the material to be heated is continuously conveyed, the time for stopping or reducing the heat generation of the heating element is variable between the material to be heated (1) The heating device according to.

(3) As a means for determining the time for stopping or reducing the heat generation of the heating element, the time for stopping or reducing the heat generation of the heating element is provided in accordance with the predetermined number of consecutively conveyed materials to be heated. The heating device according to (2), which is characterized.

(4) As a means for determining the time for stopping or reducing the heat generation of the heating element, the heat generation of the heating element is stopped or reduced in accordance with the temperature descending speed when the heat generation of the heating element is stopped or reduced. The heating device according to (1) or (2), characterized in that time is provided respectively.

(5) As means for determining the time for stopping or reducing the heat generation of the heating element, means for detecting the electric power for maintaining the heating element at a predetermined temperature and at least one reference electric power are provided. The heating device according to (1) or (2), characterized in that a time for stopping or reducing the heat generation of the heating body is provided when the detected power is higher or lower than the power.

(6) As a means for determining the time for stopping or reducing the heat generation of the heating element, a means for detecting the size of the material to be heated to be conveyed is provided, and the heat generation of the heating element is stopped or stopped according to the size of the material to be heated. The heating device according to (1), characterized in that the heating device is provided with respective reducing times.

(7) As a means for determining the time for stopping or reducing the heat generation of the heating element, the heating value of the heating element is temporarily increased when there is no object to be heated at the position of the heating element, and the heating element in the meantime. The heating device according to (1), characterized in that the time for stopping or reducing the heat generation thereafter is determined based on the amount of temperature rise.

(8) As a means for determining the time for stopping or reducing the heat generation of the heating element, the next object to be heated depending on the temperature rising rate at the time of heating again after stopping or reducing the heat generation of the heating element. The heating device according to (1), characterized in that the time for stopping or reducing the heat generation of the heating body is determined.

(9) The heating device is an image heating and fixing device for heating and fixing an image on a recording material carrying an unfixed image, according to any one of (1) to (8). Heating device.

(10) A heat resistant film is brought into contact with and slid on the heating body, a material to be heated is brought into close contact with the surface of the film opposite to the heating body, and the film is passed together with the film through the position of the heating body. A heating device for applying heat energy to a material to be heated through the film has a temperature detecting means for the heating body and means for energizing the heating body so that the temperature detected by the temperature detecting means is maintained at a constant temperature. A heating body temperature control means for stopping the energization of the heating body when the material to be heated does not exist at the position of the heating body and changing the control temperature of the heating body according to the temperature change of the heating body at that time A heating device, wherein the time during which the energization time of the heating element is stopped is longer than the time during which the temperature change of the heating element is detected at that time.

(11) A heat resistant film is brought into contact with and slid on the heating body, a material to be heated is brought into close contact with the surface of the film opposite to the heating body, and the film is passed together with the film through the position of the heating body. A heating device for applying heat energy to a material to be heated through the film has a temperature detecting means for the heating body and means for energizing the heating body so that the temperature detected by the temperature detecting means is maintained at a constant temperature. A heating body temperature control means for supplying constant power to the heating body when the material to be heated does not exist at the position of the heating body and changing the control temperature of the heating body according to the temperature change of the heating body at that time. However, the heating device is characterized in that the time during which constant power is supplied to the heating body is longer than the time during which the temperature change of the heating body is detected.

(12) The heating device according to (10) or (11), characterized in that the heating device is an image heating and fixing device that heats and fixes an image on a recording material carrying an unfixed image.

(13) A heat-resistant film is slid on the heating body, and a material to be heated is brought into close contact with the surface of the film opposite to the heating body, and the film is passed through the heating body position together with the film to move from the heating body. In a heating device for applying heat energy to a material to be heated through the film, temperature detecting means for the heating body and means for energizing the heating body so that the temperature detected by the temperature detecting means is maintained at a constant temperature T _1. And controlling the heating element to a temperature T ′ lower than the temperature T ₁ when the material to be heated does not exist at the position of the heating element, and a predetermined time from when the control is switched from the temperature T ₁ to the temperature T ′. Temperature T in
When it reaches ′, the control temperature of the heating element for the next object to be heated is set to T _1, and when it does not reach within a predetermined time, the control temperature of the heating element for the next object to be heated is lower than temperature T _1. A heating device characterized in that it is T ₂ .

(14) A heat resistant film is brought into contact with and slid on the heating body, and a material to be heated is brought into close contact with the surface of the film opposite to the heating body, and the film is passed through the position of the heating body together with the film to be removed from the heating body. In a heating device for applying heat energy to a material to be heated through the film, temperature detecting means for the heating body and means for energizing the heating body so that the temperature detected by the temperature detecting means is maintained at a constant temperature T _1. And when the material to be heated is not present at the position of the heating body, the heating body is controlled to a temperature T ′ lower than the temperature T _{1 and} when the control temperature T ′ is reached, a predetermined control temperature is always reached. When the time t is longer than a predetermined time, the control temperature of the heating element for the next material to be heated is set to a temperature T ₂ lower than the temperature T ₁ , and the time t is a predetermined time. In the case of The control temperature of the heater to T ₁
A heating device characterized by being controlled to.

(15) The heating device according to (13) or (14), characterized in that the heating device is an image heating and fixing device for heating and fixing an image on a recording material carrying an unfixed image.

(16) A heat resistant film is brought into contact with and slid on the heating body, and a material to be heated is brought into close contact with the surface of the film opposite to the heating body, and the film is passed through the heating body position together with the film to be removed from the heating body. In a heating device for applying heat energy to a material to be heated through the film, when the object to be heated does not pass through a heating region of the heating device, power is supplied to the object to be heated by H
A heating device which is controlled by a binary value of high and low, and determines a control temperature of the heating body with respect to a material to be heated next entering a heating region based on a temperature ripple of the heating body at this time.

(17) A heat-resistant film is brought into contact with and slid on the heating body, and a material to be heated is brought into close contact with the surface of the film opposite to the heating body, and the film is passed through the heating body position together with the film to be removed from the heating body. In a heating device for applying heat energy to a material to be heated through the film, when the object to be heated does not pass through a heating region of the heating device, power is supplied to the object to be heated by H
It is controlled by two values, high and Low, and at this High time or L
A heating device which determines a control temperature of a heating body with respect to a material to be heated which enters a heating region next based on a temperature change rate at the time of ow.

(18) A heat-resistant film is brought into contact with and slid on the heating body, and a material to be heated is brought into close contact with the surface of the film opposite to the heating body, and the film is passed through the heating body position together with the film to be removed from the heating body. In a heating device for applying heat energy to a material to be heated through the film, when the object to be heated does not pass through a heating region of the heating device, power is supplied to the object to be heated by H
A heating device which is controlled by binary values of high and low, and determines the control temperature of the heating body with respect to the material to be heated next entering the heating region based on the peak or bottom of the temperature ripple of the heating body at this time. ..

(19) The heating device according to (16) or (18), characterized in that the heating device is an image heating and fixing device for heating and fixing an image on a recording material carrying an unfixed image.

(20) A heating device having a heating body and a temperature detecting member for detecting the temperature of the heating body, and energizing the heating body so that the temperature detected by the temperature detecting member is kept constant at a predetermined temperature. , The various control values thereafter are determined based on the rate of temperature increase detected from the start of energization of the heating element until the temperature reaches the predetermined temperature, and the amount of electric power supplied to the heating element is set within a unit time. It is controlled by a ratio of energization / de-energization to the body, and has means for varying the ratio, and the detection time of the temperature rising rate is set to a unit time of power control to the heating body or more. Heating device.

(21) The heating apparatus according to (20), characterized in that the detection time of the temperature rising rate is an integral multiple of the unit time of power control to the heating body.

(22) The invention has a film that moves together with a recording material supporting a visible image, and the visible image is heated by heat from a heating body through the film. (20) or (21) The heating device described.

[0084]

[Operation] In a heating device having a means for controlling the energized state of a heating element, a non-energized state is created to stop energization of the heating element when there is no sheet passing, such as between sheets of continuous sheet feeding of the object to be heated. Depending on the information such as continuous paper feeding time, input power required to maintain the controlled temperature, the temperature decrease rate of the heating element after stopping the power supply to the heating element, the signal of the size of the heated object, etc. The temperature rise in the non-sheet-passing area of the heating element during continuous sheet feeding of small-sized paper can be controlled by changing the temperature of the sheet, and in the image heating and fixing device, the toner image fixability even when the device is cold. Therefore, an inexpensive and high-performance fixing system can be constructed.

.. Determining the temperature control temperature of the heating body surface when the next material to be heated comes by forcibly stopping the energization of the heating body and watching the descending speed of the heating body surface, or by supplying a constant power and watching the rising speed In the temperature control method of, by stopping the energization of the heating body or by supplying a constant power for a longer time than the time for detecting the descending speed or the rising speed of the heating body surface, eliminating false detection of control, The film temperature can be kept constant no matter what mode the device is used, and in the image heating and fixing device, fixing failure and high temperature offset can be prevented.

.. The control temperature of the heating element between the sheets is set lower than the temperature to be controlled while the material to be heated is passing through the heating region, and when the control temperature between the sheets falls within a predetermined time, a Flag is set in the control sequence, If this flag is set, the entire device such as the film is cold, so the control temperature for the next paper is the same as the previous paper, and the Flag is
If the temperature is not raised, the control temperature of the heating element is lowered to prevent the occurrence of offset and defective fixing in the image heating and fixing device.

.. By changing the temperature of the heating element based on the temperature change detected when the heating element is energized, or the temperature change detected when energized, the film temperature is kept constant no matter what timing the device is used. In the heat fixing device, poor fixing and high temperature offset can be prevented.

.. Detecting the temperature rise rate in a heating device that detects the temperature rise rate when the heating element is raised to a predetermined temperature with the electric power controlled by the wave number control, and determines various control values thereafter according to the rate. By making the time equal to the time required for one cycle of the fundamental wave number of the wave number control, it is possible to reduce the error in detecting the velocity and to perform the control after the rising more accurately.

[0089]

【Example】

<Embodiment 1> (FIGS. 1 to 4) This embodiment is an embodiment of a heating device characterized by the constitution described in claims 1 to 9 of the claims, and is a small-sized object to be heated. This is to prevent excessive temperature rise in the non-sheet passing area of the heating element during continuous sheet passing of the material and to secure good image fixing property even when the apparatus is cold.

(1) Example 1 FIG. 1 is a plan view of a heating body of the heating apparatus of the present example with a half cut-out / partially cutaway view and a block diagram for controlling the heating body surface temperature. This heating device is a film heating type image heating fixing device similar to the one shown in FIG. 31, and is a fixing device of a laser beam printer.

The structure of the heating element 2 is the same as that shown in FIG. 32. The substrate 3 is a ceramic having a good thermal conductivity and a thickness of 1 mm, and the resistance value of the electric heating element 4 is 34Ω. The temperature detecting member 8 is a thermistor, and is provided at a position that is always a paper passing area.

The output signal of the thermistor 8 is input to the CPU 32 via the A / D converter 31. Based on this input signal, the CPU 32 controls the energization power from the power source 20 to the energization heating element 4 via the AC driver 33. During the passage of the paper, the temperature of the surface of the heating element 2 is controlled to be 180 ° C.

In this example, the process speed was set to 24 mm / sec so that 4 sheets of A4 size could be output per minute, and the sheet interval during continuous sheet feeding was 57 mm, which was about 2.4 sec. At this time, as a method of changing the ratio of the non-energization time to the heating element 2 between the sheets, in this example, the CPU 32 stores the number of continuous sheets to be passed, that is, the sheet passing time.

Specifically, as shown in FIG. 2, the heating element was turned off for the first 5 sheets of paper, and was turned off for 0.5 sec. Then, the temperature was raised to 180 ° C. in 1.9 sec. At this time, the electric power to be applied to the heating element 2 was measured at the rear end of the sheet one sheet before the temperature was adjusted to 180 ° C., and the electric power was added to make the temperature again 180 ° C. ..

In this state, if the optimum electric power is not input to maintain 180 ° C. in this state, the overshoot becomes large with the electric power higher than this and a high temperature offset occurs.
Further, if the temperature is lower than this, the image does not rise up to 180 ° C., so that a defective fixing image is formed. For the next 5 to 10 sheets, the power was turned off for 1.2 sec, and the temperature was raised to 180 ° C in 1.2 sec. Also at this time, the electric power to be applied to the heating element was measured so that the temperature required for controlling the temperature to 180 ° C. was measured at the rear end portion of the sheet immediately before passing the paper, and the electric power was heated to 180 ° C. After the 10th sheet, the power is turned off for 2.0 seconds.
The temperature was raised to 180 ° C in 0.4 sec.

Using the above control method, an envelope size paper was continuously fed while comparing with the conventional control. If the temperature between the sheets is controlled to 180 ° C as in the conventional case, the surface temperature of the non-sheet passing area of the heating element will change with time as shown in Fig. 3, and it will reach 250 ° C on the 40th sheet. When A4 paper is passed in this state, paper wrinkles occur due to the step difference due to the difference in thermal expansion between the pressure roller portion corresponding to the boundary between the paper passing area and the non-paper passing area of the heating element. ..

Although a silicone rubber roller having excellent heat resistance is used as the pressure roller 10, the temperature that can be continuously used is 230 ° C. or lower, and if this state is continued for a long time, the silicone rubber will be thermally deteriorated. Raised and damaged.

In the control method of this example, the temperature of the non-sheet passing area of the heating element 2 is as shown in FIG. 4 (the temperature at the time of sheet passing is plotted).
Even on the seventh sheet of paper, the surface temperature of the heating body subsided at 210 ° C. This is because the non-energized state is provided as described above, and when parts such as the pressure roller are warmed up, the non-energized time is lengthened to cool the heating element between the sheets as much as possible.

That is, as in this example, 10 seconds after the 10th sheet is passed,
When the non-energized state of ec is provided, the temperature of the non-sheet passing area of the heating body has a temperature drop of about 20 to 30 deg on the surface during this, and the temperature rise and fall are repeated during sheet passing and sheet non-passing. As a result, the effect of suppressing the temperature rise in the non-sheet passing area of the heating element is produced.

By doing so, the paper wrinkles and the heat deterioration of the pressure roller, which have been conventionally generated, are eliminated, and a new fixing system excellent in durability can be constructed.

In this example, the heating element is not energized between the recording materials.
Although N / OFF is performed, the energization may be turned off at the trailing edge of the toner image area of the recording material, and if the temperature of the heating body is high, heating is performed from the leading edge of the recording material to the image area. It goes without saying that it is okay.

When the rate of temperature rise of the heating element is low and the heat radiation is fast, if the heat generation of the heating element is stopped, the temperature drop is too large, and the fixing temperature is reached until the next recording material reaches the fixing nip portion N. It is possible that heating is not possible. In such a case, it is possible to use a method of reducing the amount of heat generation by lowering the energization voltage or the duty of pulse energization, instead of completely turning off the energization to the heating element.

(2) Example 2 In the example of (1) above, the number of sheets passed is counted as information for changing the non-energization time between sheets, and switching is performed for each number of sheets. In this example, the recording sheet is fixed. Immediately after passing through the nip portion N, the energization to the heating body is stopped, the rate of temperature decrease on the surface of the heating body is detected, and the time to start energizing the heating body next is determined according to the speed. is there.

That is, in the case of a device having a fast descending speed, the device, for example, the pressure roller and the like are still cooled and heat is likely to be dissipated. Therefore, in this state, the energization of the heating element is restarted promptly. On the other hand, for those with a slow descending speed, heat is hard to be transferred to other members and the device has already warmed up.In this state, the non-energization time should be as long as possible to increase the temperature in the non-sheet passing area. I tried to prevent it.

As a concrete method, in this example, the controlled temperature is 1
The fall time from 80 ° C to 175 ° C is detected. If this time is 100 msec or less, the non-energization time is 0.4 se.
c, 100 to 300 msec, the non-energization time is 1.2 se
c, 300 msec or more was divided into three, namely, the non-energization time was 2 sec. Next, for the method to start up to 180 ° C, see (1) above.
Is similar to the example.

By doing so, the temperature rise in the non-sheet passing area of the heating element could be suppressed as shown in FIG. 4 as in the case of the above (1). Further, in the above example (1), the number of sheets passed is uniquely changed, but in this example, since the change is reflected in consideration of the warming state of the apparatus, the control has higher environmental adaptability.

In the above, immediately after the recording material has passed through the fixing nip portion N, the power supply to the heating body 2 is reduced and the warming condition of the apparatus is measured. However, conversely, it is possible to measure the degree of warming of the apparatus by heating for a certain period of time, for example, about 0.3 sec and measuring the temperature rising rate. Alternatively, the non-energization time between the sheets may be changed by determining the warming state of the apparatus based on the temperature rising rate from the non-energization time between the previous sheets.

Further, since the calorific value is insufficient at the initial stage of continuous printing, the interval between sheets is determined by the temperature rising rate while heating between sheets, and the temperature decreasing rate while cooling in the non-energized or low power state between sheets from the middle. It is also possible to combine so as to determine the space between sheets.

(3) Example 3 This example was carried out by detecting the electric power required to maintain the heating element at 180 ° C. as information for changing the non-energization time during non-sheet passing.

As in the case of the above (1) and (2), if the pressure roller material is cooled to maintain the temperature of the heating body at 180 ° C., the heat taken up by them is large, and therefore about 200.
Power of about W is required. However, when the paper is continuously fed and the pressure roller and the like are warmed up, the amount of heat taken by these is reduced, and in order to maintain the temperature of the heating body at 180 ° C., the power of about 100 W is sufficient.

In this example, paying attention to this fact, 18
A means for detecting electric power required to maintain the temperature of the heating element at 0 ° C. was provided, and the non-energization time between paper sheets during the next non-paper passage was determined according to the input electric power during paper passage.

Specifically, when 180 W or more is required to maintain the heating body temperature at 180 ° C., the non-energization time is 0.4
sec, 180 to 130 W, the non-energization time is 1.2
sec, 2 seconds when 130 W or less. Next, the method of raising the temperature to 180 ° C. is the same as in the example of the above (1).

By doing so, the temperature rise of the heating element could be suppressed to about 210 ° C. even when seven envelopes were continuously fed, as in the cases of the above (1) and (2).

(4) Example 4 In the above examples (1) to (3), the non-energization time during non-sheet passing is changed irrespective of the paper size, but this may be performed only for small size sheets. Good. For example, in the laser beam printer used in the description of the present embodiment, the maximum paper passing size is the LTR size, so a size smaller than this size, for example B
The above examples (1) to (3) are applied only to five sheets of paper and envelopes. As a method of detecting the paper size, if the paper is fed from a cassette, the paper size signal from the cassette is detected. A sensor is installed in the paper feed section, this sensor detects the length of the paper, and the paper size is detected based on this information. However, any method may be used as long as the paper size is known.

When it is determined that the small size papers are continuously passed in this way, for example, the space between the papers is 2 sec.
It is possible to make the length c longer and set the interval between small size papers to 4.4 seconds while the interval between letter size papers is 2 to 4 seconds, and change the non-energization time in that interval. As a result, it is possible to lengthen the cooling time between small-sized paper sheets, and further reduce the non-sheet-passage temperature rise.

By doing so, the throughput does not decrease when the maximum paper size is passed, and the throughput slightly decreases only when the small size paper is passed, but the temperature rise of the non-paper-passing portion can be prevented more effectively. it can.

In this example, as described above, the small size of the recording material is detected by the sensor provided at the paper feeding position, and when the small size paper is passed, the distance between the papers is about 106 m.
The time of non-energization time was changed to m and 4.4 sec. Specifically, the power was turned off for 1.0 sec from 1 to 5 sheets of paper, and the temperature was raised to 180 ° C. for the remaining 3.4 sec. Paper passing 5 to 10 sheets is 1.7 sec off, 1.7 on, paper passing 1
After the 0th sheet, energization control was performed by turning off for 3.8 seconds and turning on for 0.6 seconds.

By doing so, the temperature rise of the non-sheet passing portion is further suppressed, and after passing 70 sheets, the temperature of the surface of the heating body is lowered by 10 deg more than that of the above examples (1) to (3), and more stable sheet feeding is possible. It has become possible.

As the information for changing the non-energization time between sheets, the information may be detected by detecting the descending speed when the energization is off and the electric power for maintaining 180 ° C. as in the examples (2) and (3). The same effect can be obtained.

As in the above examples (1) to (4), B5
When continuously passing small size paper such as paper and envelopes, create a heating element non-energization state between the paper sheets and change the non-energization time according to the state of the device to heat the small size paper. The temperature rise in the non-sheet passing area can be suppressed, and the adverse effect due to the excessive temperature rise of the heating element in the non-sheet passing area can be eliminated.

<Embodiment 2> (FIGS. 5 to 14) This embodiment relates to claims 10 to 12 of the claims.
An embodiment of a heating device characterized by the configuration described in (1) above, which eliminates the problem of (B), that is, erroneous detection of control with respect to a change in temperature of the heating body, in which mode the device is operated. Even when used, the temperature of the film can be kept constant, and fixing failure of the image heating and fixing device as a heating device and high temperature offset are prevented.

(1) Example 1 The structure of the image heating and fixing device as the heating device and the structure of the heating body are the same as those shown in FIGS.

In the apparatus of this example, first, when the heating body is started up, the heating body is started up at a constant power of 500W.
This is because the electric power is supplied so as to be a constant electric power by the electric power control means by pulse width modulation such as phase control and wave number control based on the information of the AC voltage detection circuit, the energization heating element resistance detection means and the like (not shown). ..

In this example, the fundamental wave number for wave number control was 20 waves at f to 50 Hz and V _{ac to} 100 V, and the heating body was started up under the conditions of 14 waves-ON and 6 waves-OFF. At this time, if the entire apparatus is cold, the rising speed of the heating element 2 becomes slower. Conversely, if the entire apparatus such as the pressure roller 10 and the stay 14 is warm, the rising speed becomes faster. Therefore, the state of the device can be estimated by detecting this speed, and the temperature of the film on the first sheet of paper being passed can be determined by fixing failure and high temperature offset by deciding the heating member set temperature of the first sheet of paper passing according to these. It can be set to a non-existent area.

Next, a case where recording sheets are continuously placed will be described. This sets the heating body temperature by an algorithm as shown in FIG. That is ,. The heating element 2 is forcibly turned off for 0.6 sec at the same time when the recording material P leaves the fixing nip portion N. Next, while the heating element 2 is turned off, 0 to 0.5 se
Measure how much the heating element temperature decreases between c. From this measurement, the temperature control temperature of the heating element 2 at the time of the next sheet passing is determined according to Table 1. ． The temperature control of the heating element 2 for the next recording material P is started.

This is because the descending speed is detected during the heating body off time and it is erroneously detected if the two are kept the same as in the conventional case, and the heating body temperature is still 210 ° C. as shown in FIG.
What was needed was to switch to 200 ° C, and a defective fixing image could be ejected. Set the temperature of the heating element surface according to Table 1 without erroneous detection as shown in Fig. 7. Come to do.

By doing so, it is possible to reliably detect the temperature lowering speed of the heating element, and the state of the entire apparatus such as the pressure roller can be estimated from these information, so that the heating element set temperature can be changed. The film temperature can be made constant as shown in FIG. 8, and fixing failure and high temperature offset can be prevented.

(2) Example 2 In the example of (1) above, the descending speed of the heating element 2 was detected.
Similar effects can be obtained by changing the heating body temperature control temperature according to the reached temperature of the heating body 2 after a certain time as in this example.

Specifically, the heating element temperature is set by the algorithm shown in FIG.

.. The heating element 2 is turned off for 1.7 seconds at the same time when the recording material leaves the fixing nip portion N. Next, after 1.5 seconds, the temperature reached by the heating element 2 is measured. From this value, the heating temperature control temperature at the time of the next paper passing is shown in Table 2.
To decide according to ． The temperature control of the heating element 2 for the next recording material P is started.

By doing so, the heating element temperature can be controlled without erroneous detection as in the case of the above (1),
As a result, the temperature of the film becomes constant, and high temperature offset and improper fixing can be prevented.

(3) Example 3 In the example of (1) above, the energization of the heating element 2 was stopped and the descending speed was started to be detected at the same time. This is done after stopping the energization of. That is, the temperature control temperature of the next heating element is determined by the algorithm shown in FIG.

.. In the heating body 2, the recording material P has the fixing nip portion N.
When it goes out, it is forcibly turned off for 0.7 sec. Next, 0.1 to 0.6 while the heating element 2 is off
Measure how much the temperature of the heating element drops in the period of sec. From this measured value, the temperature control temperature of the surface of the heating element at the time of the next sheet passing is determined according to Table 3. ． The temperature control of the heating element 2 is started.

This is shown in FIG. 11 for observing the descending speed of the heating element.
The detection is eliminated after the start of the measurement.

By doing so, as shown in FIG. 12, even if the heating body descending speed varies in the conveying speed of the recording material P and the timing of the trailing edge passing through the fixing nip portion N varies, accurate measurement can be performed. A good fixed image can be obtained by changing the next heating member set temperature according to the information.

(4) Example 4 In this example, a method will be described in which a temperature control mode is provided between the sheets and the temperature is lowered to 0.5 sec determined by the temperature.

As described above, this is because the temperature is detected only by the temperature even if the paper interval temperature control mode is entered by 0.5 sec. For this reason, if the temperature is higher than the temperature control temperature after 0.5 sec, it is determined that the device is warmed up, and the temperature control temperature of the heating element is lowered.

In this example, in order to eliminate such erroneous detection, the temperature control temperature of the heating element is determined by the algorithm shown in FIG. ． When the recording material P passes through the fixing nip portion N, the heating element 2 is forcibly turned off for 1.7 seconds. Measure the temperature reached 1.5 seconds after turning off the heating element. Based on this measured value, the next controlled temperature is determined according to Table 4. ． When the paper interval is long, the paper interval temperature control mode is set at a position 15 deg lower than this temperature control temperature. When the recording material P arrives at the fixing nip portion N, the temperature control mode at the time of passing the paper is entered.

By doing so, the temperature of the surface of the heating element becomes as shown in FIG. 14, and even if the second temperature adjustment mode is provided between the sheets, the surface temperature adjustment temperature of the heating element can be adjusted without erroneous detection. You can change.

(5) Example 5 In the above examples (1) to (4), the heating element was forcibly turned off between the sheets and the temperature drop was observed, but conversely, a constant electric power was forcibly applied between the sheets. When the temperature of the heating element 2 is turned on and the rising temperature change is observed in a shorter time than the turning on time, the state of the apparatus can be understood, and the temperature control temperature of the heating element 2 at the time of the next sheet passing can be reliably determined.

As in the above examples (1) to (5), the time during which constant power is supplied to the heating element 2 or the energization is forcibly stopped is longer than the time during which the temperature change of the heating element 2 is observed. There is an effect that it is possible to eliminate erroneous detection when the temperature of the heating element 2 is changed by increasing the length.

<Embodiment 3> (FIGS. 15 to 18) This embodiment relates to claims 13 to 15 of the claims.
An embodiment of a heating device characterized by the configuration described in (1), which eliminates the problem of (B) as in the case of the second embodiment, that is, erroneous detection of control with respect to temperature change of the heating body,
The temperature of the film can be kept constant regardless of the mode in which the device is used, and fixing failure and high temperature offset of the image heating and fixing device as a heating device are prevented.

(1) Example 1 The structure of the image heating and fixing device as the heating device and the structure of the heating member are the same as those shown in FIGS.

Similar to the example (1) of the second embodiment, the heating element 2 is started up with a constant power of 500W. In this example, the fundamental wave number of the wave number control was 20 waves at f to 50 Hz and V _{ac to} 100 V, and the heating element 2 was started up under the conditions of 14 waves-ON and 6 waves-OFF.

At this time, if the entire apparatus is cold, the ascending speed of the heating body becomes slow, and conversely, if the entire apparatus such as the pressure roller 10 and the stay 14 is warm, the ascending speed becomes faster. Therefore, the state of the device can be estimated by detecting this speed, and the temperature of the first sheet of the sheet to be passed can be determined according to these to determine the temperature of the first sheet of the sheet to a region where there is no defective fixing and high-temperature offset. It can be set to the same as in the second embodiment.

Next, a case where recording materials P are continuously placed will be described. This sets the heating body temperature by an algorithm as shown in FIG.

In the heating element 2, the recording material P has the fixing nip portion N.
At the same time when the control temperature is exited, the control temperature T ₁ is switched to T '.
To start the timer. If the temperature T of the heating element 2 is higher than T ', NO is selected. If the timer does not reach the sampling time, return to. And Y
In case of ES, set Flag with. Then, the temperature control between the sheets is started and controlled to T '. If the timer exceeds the sampling time, the heating body is controlled without turning on the flag by T '. And F for the next recording material
If the lag is standing, the same temperature T as the recording material before going to
₁ controls the heating element. If the flag is not raised at, the control temperature is changed to T ₂ and the next recording material is fixed. FIG. 16 shows the temperature change of the heating element 2 when controlled in this manner.

In this way, when the Flag is set as a standard, it is determined that the apparatus is cold, and the control temperature during sheet feeding is not changed. When there is no Flag, the control temperature is lowered to fix the film temperature. It can be controlled within a temperature range where neither defects nor high temperature offset occur.

(Experimental Example) As shown in Table 5 below, the control temperature of the heating element 2 during sheet feeding was sequentially switched. That is, if the Flag does not stand, 180 ° C → 170 ° C, 170 ° C → 163
C., 163.degree. C..fwdarw.155, and the control temperature of the heating element during paper passing was changed. The sampling time was t _{0 =} 0.3 sec.

[0150] As a result, as shown in FIG. 17, the temperature of the film could be controlled within a range in which neither high temperature offset nor defective fixing occurred.

(2) Example 2 In the example of (1), the following control temperature was determined by using the flag as a guide. In this example, it is determined whether or not the timing to enter the inter-paper temperature control is early. That is, the time t from when the control temperature between the sheets is reached to a predetermined time t ₀ ′ (this time may be a fixed time after the control of the sheet interval is started) is measured.

This time t is short when the film, the pressure roller and the like are warm and long when the film and the pressure roller are cold.

Therefore, when this time t is as short as t ₁ as shown in FIG. 18A, the control temperature for the next recording material is lowered to T ₂ . On the other hand, as in (b), t is t ₂
If the temperature is long, the control temperature of the next recording material is maintained at T ₁ .

The control temperature during the sheet passing and the sheet interval is the same as in the embodiment, and when t ₀ ′ is 0.3 sec, t ≦ 0.2 s.
In ec, the control temperature of the next recording material is set to be the same as that of the previous recording material in the following case, and when 0.3 ≧ t> 0.2 sec, the control temperature of the next recording material is lowered by one step (that is, the previous recording material). When the recording material is controlled at 180 ℃, the next recording material is 170
(Lowered to 0 ° C.), the same result as that in FIG. 17 was obtained.

As in the above examples (1) and (2), it is possible to obtain a quick-start heating device in which neither high-temperature offset nor defective fixing occurs. <Embodiment 4> (FIGS. 19 to 22) This embodiment includes claims 16 to 19 of the claims.
An embodiment of a heating device characterized by the configuration described in (1), which eliminates the problem of (B) as in the case of the second embodiment, that is, erroneous detection of control with respect to temperature change of the heating body,
The temperature of the film can be kept constant regardless of the mode in which the device is used, and fixing failure and high temperature offset of the image heating and fixing device as a heating device are prevented.

(1) Example 1 The structure of the image heating and fixing device as the heating device and the structure of the heating member 2 are the same as those shown in FIGS.

FIG. 19 is a time change chart of the temperature of the heating element, the temperature of the film, and the temperature of the pressure roller during continuous printing in this example.

First, when the heating element is started up, the heating element temperature is set according to the algorithm of FIG. 20 and Table 6.

[0159] The heating element 2 is started by energizing with a constant power of 700W.
When the temperature of the heating element reaches 165 ° C, the energizing power is 500W.
Change

That is, based on the information of the AC power supply voltage detection / heater resistance detection means and the like, the power control means by pulse width modulation such as phase control and wave number control supplies electricity so that constant power is obtained. In this example, f to 50 Hz, V _{ac to} 100
When the AC voltage of V was 100%, the AC voltage was repeatedly 100 msec-ON and 40 msec-OFF with the heating body of 700 W, and the constant power supply of 500 W was performed.

At this time, if the entire apparatus is cold, the heating element 2
The rate of increase of the speed becomes slower, and on the contrary, the speed of increase becomes faster if the entire device is warm. Therefore, the temperature of the pressure roller and stay can be estimated by looking at the rising speed of the heating element 2, and by changing the set temperature of the heating element for the first sheet of paper in accordance with the temperature, the entire device can be used up to that point. Even if it is distorted, the film temperature can be kept constant by a simple operation to prevent fixing failure and high temperature offset.

In the paper passing state, for example, 200 °
When controlling to C, the control is performed so as to reduce the temperature ripple by alternately switching a slightly higher power and a slightly lower power required.

For example, if the electric power required to maintain 200 ° C. is 180 W, then High 190 W and Low 170
Control is performed to switch W as appropriate.

This is because it is difficult to accurately match the required electric power to both the phase control and the wave number control, and variations in the heat capacity of the device and how to warm up the device are as described above.
This is because it is better to switch and control at two levels of w. And the high level is 190W between sheets
And the Low level is greatly reduced, for example, 0 W.

Then, a large temperature ripple is generated as shown in FIG. This temperature ripple becomes large as shown in (a) because the pressure roller 10 and the film 1 are abruptly radiated with heat from the heater 2 when the apparatus is cold. On the other hand, the ripple after printing about 50 sheets continuously is small as shown in (b) because the apparatus is warm.

Therefore, by measuring the magnitude of this ripple T _p -T _b , it is possible to determine the degree of warming of the pressure roller 10 and the film 1, and therefore, the paper passing based on this T _p -T _b . By switching the control temperature at that time, it is possible to continue printing without any offset or defective fixing.

In FIG. 19, the control temperature is switched according to the magnitude of ripple according to Table 7.

[0168] In this way, by controlling the temperature of the heating element based on the degree of warming of the apparatus and gradually lowering it during continuous printing, it is possible to prevent defective fixing and offset.

The control of High and Low between the sheets may be performed not in the entire sheet interval but in a part thereof, and the proper control temperature can be reached before the next recording material P enters the fixing nip portion N. The control may be switched to the control when the recording material is present at the timing.

[0170] (2) has been controlled based on T _p -T _b in the example of Example 2 above (1), T _{b
Alternatively} , it may be controlled based on T _p .

When Table 8 was used as the control at T _b and Table 9 was used as the control at T _p , it was possible to continue the continuous printing in both cases with no offset fixing failure.

[0172] (3) Example 3 In the examples of (1) and (2), the heating element was controlled at the same temperature as that during sheet feeding, but in this example, the control temperature between sheets is 15 deg or more than that during sheet feeding. To lower.

As a result, the temperature rise of the apparatus during continuous printing is suppressed, and the heating element 2 for continuous printing of small size paper is performed.
It is possible to reduce the temperature rise in the paper non-passage area and to prevent unnecessary power consumption.

Further, it is possible to increase the ripple and the like, and thereby to improve the detection accuracy.
A comparison of this ripple is shown in FIG. (A) is the case of the above example (2), and (B) is the case of this example.
T is a control temperature during sheet feeding, and T'is a control temperature between sheets.

As in the above examples (1) to (3), a temperature ripple is generated by controlling the electric power supplied to the heating element 2 between the paper sheets at a high level and a greatly reduced low level. The control temperature for the next recording material P can be switched depending on the size, and continuous printing can be performed without causing offset and fixing failure. <Embodiment 5> (FIGS. 23 to 30) The present embodiment includes claims 20 to 22 of the claims.
It is an embodiment of a heating device characterized by the configuration described in (3) above, which solves the problem (C). That is, when the heating element is raised to a predetermined temperature with the amount of electric power controlled by the wave number control, the heating rate is detected, and in the heating device that determines various control values thereafter according to the rate,
The error in speed detection is reduced, and the control after rising is performed more accurately.

(1) Example 1 The structure of the image heating and fixing device as the heating device of this example and the structure of the heating body are the same as those shown in FIGS.

However, the laser beam printer equipped with the image heating and fixing device is a printer which outputs 6 sheets of A4 size paper at a recording material feeding speed (process speed) of 56 mm / sec.

The heating element is started up by a constant power of 500W. At this time, so that the power supplied to the heating element will be 500 W regardless of the input voltage of any voltage, the wave number is applied to the heating element based on the information of the AC voltage detection circuit, heater resistance detection means, etc. (not shown). You are in control.

In this example, f to 50 Hz, V _{ac to} 115 V
The basic wave number of the wave number control was set to 20 waves with the AC voltage of 10 and the heating body was started under the conditions of 10 waves-ON and 10 waves-OFF.

Therefore, the time t _W required for the fundamental wave number to repeat one cycle is t _W = 1.0 (sec) × [20 (wave) ÷ {50 (Hz) × 2}] = 0.2 (sec ) = 200 (msec).

Here, the reason why it becomes 50 (Hz) × 2 is that the half wave of AC is counted as one wave in the wave number control of this example. That is, there are 100 waves per second.

By the wave number control, the temperature of the heating body continues to rise while drawing a minute temperature ripple, and when the temperature detected by the thermistor reaches 120 ° C, the CPU 32 (FIG. 1) causes the CPU 32 (FIG. 1) to continue for a certain time t _base . Detect the rate of temperature rise.

More specifically, when the temperature reaches 120 ° C., the CPU 32 starts the timer to set a fixed time t _base.
Later, it will be measured how many degrees the temperature has risen.

That is, the heating rate here is t _base
An average heating rate of between a temperature between t _base is Tde
When the temperature rises by g, the heating rate v becomes v = dT / d (t _base ).

At this time, if the entire apparatus is cold, the heating element 2
The rate of temperature rise is slower, and on the contrary, it is faster if it is warm. Therefore, the temperature of the pressure roller 10 and the stay 14 can be estimated by looking at the temperature increase rate v, and the control values such as the temperature control temperature of the first sheet passing and the supplied power are determined according to them. In this example, the temperature control temperature is determined by the control table shown in Table 10.

[0186] Under the conditions of this example, the heating rate of the heating body is about 150 when the heating body temperature is between 100 ° C. and 160 ° C. when the fundamental wave number is ON.
The present inventors have confirmed that it is deg / sec. It should be noted that this is the maximum value of the heating rate of the heating body in the apparatus of this example.

FIG. 23 is a wave number ripple when the temperature of the heating element 2 of the apparatus of this example rises. The average rate of temperature rise of the heating element 2 in units of the fundamental wave number is represented by the slope ξ of the line Q.

This rate matches the rate of temperature increase detected when the heating element 2 of this example is started up at full energization without inputting wave number control at 500 W input.

That is, the constant power control using the wave number control also has the meaning of always obtaining the average rising rate of ξ under the condition that the temperature rise is ξ.

Therefore, the output value detected when the temperature increase rate is detected must be one that draws a line with a slope ξ, or one that is high.

In this example, the above-mentioned temperature increase rate measurement time t
_{The base is set} to 200 nsec and is equal to the time t _W required for one cycle of the fundamental wave number. That is, t _base = t _w .

FIG. 24 shows the timing of temperature increase rate detection when this embodiment is applied. The temperature at which the heating body rises in one cycle t _w of the fundamental wave number is always constant regardless of the timing of the fundamental wave number.

Therefore, if the measurement time t _base of the temperature rising rate is made equal to one cycle t _w of the fundamental wave number, the measurement is started (12
Counting from 0 ° C), always for one cycle of the basic wave number is performed the measurement of the temperature at the stage of completion, t heating rate in the _{base v = dT / d (t} base) course of the Figure 23 tilt It will have the same value as ξ.

That is, no matter what position in the fundamental wave number the measurement is started, the error (dispersion of the measured value), which has been a problem in the past, does not occur at all.

In this example, the case where the fundamental wave number is 20 waves is described, but it goes without saying that the value of the time t _base is changed if the fundamental wave number is changed. For example, in 10-wave-number control, 100 msec, 15 m-150 msec for wave number control
Becomes

The number of waves for turning on the heating element in the basic wave number is not limited to 10 waves, and can be changed from 0 wave to 20 waves by controlling 20 waves.

Of course, the constant power control value is variable depending on the device and is not limited to 500 W in this example.

The same applies to the following examples (2) to (5).

As described above, by making the temperature rising rate measurement time equal to the time required for one cycle of the fundamental wave number, the temperature rising rate can be accurately increased no matter where the measurement of the temperature raising rate is started. Can detect speed.

(2) Example 2 In the example of the above (1), the measurement time t _{base of the} heating rate is
Was set to the same time as one cycle t _w of the fundamental wave number, but the measurement time t _base may be an integral multiple of the fundamental wave number cycle t _w . That is, t _base = nt _w (n = 1, 2, 3, ...) May be used.

As described above, the temperature rise in the fundamental wave number period does not change at any timing. This is the same regardless of how many times the fundamental wave number is output. Therefore, even if the temperature rise is measured for a unit of an integral multiple of the fundamental wave number period, the temperature rise can be detected without variation as in the case of the above example (1). That is, an accurate heating rate can be obtained.

For example, in the case of 20-wave control, the equal magnification is 200 m
sec, 2 times 400 msec, 3 times 600 msec
It becomes ...

FIG. 25 shows this, and it can be seen that all the temperature rising straight lines have the same slope if they are integral multiples.

Therefore, as shown in the example of (1) above, the variation of the detection speed is zero at the same magnification of the fundamental wave number cycle, so that the variation is the same if the measurement time is an integral multiple of the fundamental wave number cycle. It is zero.

As described above, if the measurement time is doubled or tripled, even a minute timing shift when the CPU 32 (FIG. 1) measures can be absorbed within the measurement time.
It is possible to detect the temperature rise rate more accurately than the case of measuring at the same magnification.

When an A / D converter 31 for A / D converting the output of the thermistor 8 having a low bit number is used, the temperature resolution that can be detected by the CPU 32 is low, and the temperature can be detected completely accurately. However, if the measurement time is taken longer, the A / D converter 3
It is also possible to absorb a low resolution of 1.

(3) Example 3 In the example of (2) above, the measurement time of the heating rate is defined as t _base = nt _w (n = 1,2,3 ...) Which is an integral multiple of the fundamental wave number period. However, t _base may be in the vicinity of an integer multiple of t _w .

FIG. 26 shows two temperature rise curves on one graph for two types of measurement timings.

Normally, when the temperature increase rate is measured over a period of time, the variation in the detected value (difference between the maximum detectable value and the minimum detectable value) is minimum at the position K where the measurement time is an integral multiple.
It becomes zero and then increases again as the time increases, and becomes maximum at the position J where ON / OFF is switched in the fundamental wave number of the ascending curve a.

Ideally, the measurement at the position K is the most accurate as in the cases of the above (1) and (2), but even in the vicinity of the position K, the dispersion of the measured values is practical. It fits within the range where there is no problem.

More specifically, in the case of the control table of Table 10, the measurement time can be set to the range of an integral multiple of the fundamental wave number period plus 10% of the fundamental wave number period and minus 10% of the fundamental wave number period. is there.

In this case, the control value may be shifted up or down by one on the table due to the variation in the measured value. However, in reality, it is ideal because of the performance of the A / D converter 31 that has been touched before. Even if the measurement is performed at various positions, variations may occur, and the shift of about one degree in this case does not pose a problem in practice.

Therefore, if the measurement time and the control table are decided so that the control values do not shift up and down by two or more on the table, and there is no practical problem with the control table, the measurement time is an integer of the fundamental wave number. It may not be doubled and may be in the vicinity thereof.

(4) Example 4 It was described above that the longer the measurement time, the more the variation in the measurement value can be absorbed. However, this is not limited to the case where the measurement time is an integral multiple of the fundamental wave number period, but rather The effect is greater when it is a non-integer multiple.

Therefore, when the measurement time is set to be long to some extent, the measurement time settable range of the above example (3) (that is, the range where only one control value shifts on the table as in the example of (3)). Can be wider.

FIG. 27 shows the settable range of the measurement time which is the allowable range when the table of Table 10 is used for the two types of measurement timings of FIG. In FIG. 27, the shaded area is a non-settable area.

That is, the straight line O in the figure shows 60 deg / sec with respect to the straight line Q having an average heating rate of 70 deg / sec, and the intersection of this straight line O and the two kinds of heating body temperature rise curves in the figure is shown. The area surrounded by the straight line drawn at right angles to the time axis and the heating element temperature rise curve is the range where the variation in the detected value is 10 deg / sec or more, and it is not possible to set the measurement time in this range. Appropriate.

Therefore, the measurement time may be set in any manner other than the shaded area. That is, if the measurement time is set within this range, even if the average temperature rise rate may shift by one level on the table, it does not shift by two levels or more, and the control temperature can be limited to a shift of 4 deg or less.

Further, FIG. 28 shows the variation of the detection speed depending on the measurement time. As the measurement time becomes longer, the detection speed at the variation maximum position J approaches the average temperature increase rate ξ. .. This is why the settable range expands as the measurement time increases.

[0220] Further, although a natural consequence from the above, if the intersection of the no longer exists any more measurement time over 27, the measured time t _base is very any value without regard to the basic wave number cycle Good.

In the case of the table of Table 10, the above condition is satisfied from the position P of FIG. As can be seen from the above, in this example, the settable range of the measurement time is determined by the table.

That is, the control may be roughly rough,
If the number of table switching steps is small, the measurement time may be short.

More specifically, in the table of Table 10, the variation of the detected values is allowed up to 10 deg / sec,
In the table as shown in Table 11, the deviation is up to 20 deg / sec and the settable range is wide.

If the control value correction mechanism is provided for the shift of the control value before the temperature control temperature is reached or before the temperature control temperature is reached, the measurement time can be set. It is also possible to take a wider range.

[0225] (5) Example 5 In the above examples (1) to (4), the timing for measuring the temperature rising rate is simply defined by the measurement time, but it may be defined by the temperature range in which the measurement is performed. in this case,
The temperature range may be set so that the short time required for passing the temperature of the heating body in the temperature range in which the measurement is performed is equal to or longer than the measurement time within which the variation in the measured value falls within the allowable range.

That is, the temperature range may be wide in an apparatus having a large maximum temperature rising rate, and may be narrow in a system having a small maximum temperature rising rate.

At this time, this temperature range is defined as T _{base
Assuming that the} time required for passing between bases is t, the heating rate v can be expressed by v = d (T _base ) / dt.

In this example, the heat fixing device and the control table having the same basic structure as the examples (1) to (4) are used, and the measurement temperature range is set to 100 ° C to 160 ° C. FIG. 29 shows the measurement timing of this example.

When the heating body is energized and the heating body temperature rises, the thermistor detection temperature becomes 100 ° C to 160 ° C.
In between, the temperature rising rate is detected.

More specifically, the thermistor detection temperature is 1
The time from when the temperature reaches 00 ° C to when 160 ° C is detected is measured.

The conditions here are the same as those in the above example (4), but unlike the case where the measurement timing is defined by the measurement time, the minimum required time for the measurement is small when the measurement timing is defined by the temperature range. Become longer. FIG. 30 shows this.

When the measurement timing is defined in the temperature range as shown in FIG. 30, the measurement time is determined by the time from the last detection of the measurement start temperature to the first detection of the measurement end temperature. At this time, the heating element O in the fundamental wave number
It is obvious that the measurement end point is never reached at FF.

Therefore, in the above example (4), the minimum required time was 716 msec when the heating element was OFF, but when measuring in the temperature range as in this example, 2
0 wave control, 10 wave-ON, 10 wave-OFF, 716m
800 ms, which is an integral multiple of the fundamental wave number period exceeding sec
ec is the minimum required time.

In this example, the required transit time between 100 ° C. and 160 ° C. is 830 msec, and four basic wave numbers are included. That is, the required transit time exceeds the minimum required measurement time of 800 msec, and the variation in the measured values falls within the allowable range.

As described above, the variation can be suppressed within the allowable range by setting the measurement temperature range so that the minimum necessary measurement time can be obtained at any time.

As in the above examples (1) to (5), when the heating element is raised to a predetermined temperature with the amount of electric power controlled by the wave number control, the rate of temperature increase is detected, and the rate of temperature increase is detected. In the heating device that determines various control values after that, the error in speed detection is reduced by setting the temperature rise speed detection time at least equal to the time required for one cycle of the fundamental wave number of wave number control. , It became possible to perform the control after the start up more accurately.

[0237]

As described above, according to the present invention, in the film heating type heating device, it is possible to suppress the excessive temperature rise phenomenon in the non-sheet passing area of the heating body during continuous sheet feeding of the small-sized material to be heated. When the heating device is an image heating and fixing device, the film temperature can be kept constant regardless of the mode in which the device is used without erroneous control detection for changes in the temperature of the heating element. In addition, it is possible to prevent improper fixing and high-temperature offset to ensure good image fixability.

Further, when the heating element is raised to a predetermined temperature with the electric power controlled by the wave number control, its heating rate is detected, an error in detecting the speed is reduced, and the control after rising is further improved. Can be done accurately.

[Brief description of drawings]

FIG. 1 is a plan view of a heating device (image heating and fixing device) of Example 1 in which a heating member is partially omitted and partially cut away, and a block diagram of an energization control system.

FIG. 2 is a schematic graph of a method of energizing a heating element.

FIG. 3 is a temperature change graph of a paper-passing portion and a non-paper-passing portion of a heating body during paper feeding according to a conventional control method.

FIG. 4 is a temperature change graph of a sheet passing portion and a sheet non-passing portion of a heating body when passing a sheet by a control method according to the present invention.

FIG. 5 is a heating body control algorithm of the heating apparatus according to the second embodiment.

FIG. 6 is a heating body temperature change graph showing erroneous detection in the conventional control method.

FIG. 7 is a graph of heating body temperature change in the control method according to the present invention.

FIG. 8 is a graph showing the temperature changes of the heating element and the film for each number of passed sheets.

FIG. 9 Heater control algorithm

FIG. 10: Heated body control algorithm

FIG. 11 is a heating body temperature change graph showing erroneous detection in the conventional control method.

FIG. 12 is a graph showing a temperature change of a heating body in the control system according to the present invention.

FIG. 13 Heater control algorithm

FIG. 14: Temperature change graph of heating element

FIG. 15 is a heating body control flowchart of the heating device according to the third embodiment.

FIG. 16: Heating body temperature change diagram

FIG. 17: Temperature change diagram of heating element and film

FIG. 18: Heating body temperature change diagram

FIG. 19 is a diagram showing a heating body, a film
Temperature change diagram of pressure roller

FIG. 20: Heated body control algorithm

FIG. 21 is a diagram showing a paper-to-paper ripple.

FIG. 22 is a diagram showing a paper-to-paper ripple.

FIG. 23 is a diagram showing a temperature change of a heating body at the time of controlling the wave number of the heating apparatus of the fifth embodiment.

FIG. 24 is a diagram illustrating detection timing.

FIG. 25 is a diagram showing a heating rate for each fundamental wave number.

FIG. 26 is a diagram showing a measurement error within the fundamental wave number.

FIG. 27 is a graph showing undetectable time.

FIG. 28 is a diagram showing that the measurement error decreases with time.

FIG. 29 is a diagram for explaining measurement of a heating rate.

FIG. 30 is a diagram for explaining measurement of a heating rate.

FIG. 31 is a schematic configuration diagram of an example of a film heating type heating device (image heating and fixing device).

FIG. 32 is a plan view of a heating body with a partly cutaway and partially omitted

FIG. 33 is a schematic configuration diagram of another example of a film heating type heating device.

[Fig.34] Heater temperature / film temperature during printing
Schematic diagram showing the time variation of the surface temperature of the pressure roller (for each number of sheets passed)

FIG. 35 is a temperature change temperature change graph when erroneous detection is performed.

FIG. 36 is a temperature change temperature change graph at the time of false detection.

FIG. 37 is a temperature change diagram of the heating element

FIG. 38 is a temperature change diagram of the heating element.

[Explanation of symbols]

 1 Heat Resistant Film 2 Heater 3 Heater Substrate 4 Electric Heater 5/6 Power Supply Electrode 7 Surface Protective Layer 8 Temperature Detection Member (Thermistor) 9 Temperature Fuse 10 Pressure Roller 11 Drive Roller 12 Driven Roller T Toner Image P Recording Material 20・ 31-33 energization control system

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Yoshimoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Innovator Hidenobu Suzuki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Tomoko Nanbu 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Daizo Fukuzawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (22)

[Claims] 1. A heat-resistant film is brought into contact with and slid on a heating body, and a material to be heated is brought into close contact with the surface of the film opposite to the heating body, and the film is passed through the heating body position together with the film to remove the heat from the heating body. In a heating device that applies heat energy to a material to be heated through a film, if there is no material to be heated at the position of the heating body, a time to stop or reduce heat generation of the heating body is provided. Characteristic heating device. 2. The time for stopping or reducing the heat generation of the heating body between the materials to be heated when the materials to be heated are continuously conveyed is variable. The heating device described. 3. The time for stopping or reducing the heat generation of the heating body is provided as means for determining the time for stopping or reducing the heat generation of the heating body, in accordance with a predetermined number of continuously conveyed materials to be heated. The heating device according to claim 2. 4. The time for stopping or reducing the heat generation of the heating body as a means for determining the time for stopping or reducing the heat generation of the heating body according to the temperature descending speed when the heat generation of the heating body is stopped or reduced. 3. The heating device according to claim 1, wherein the heating device is provided respectively. 5. A means for detecting electric power for maintaining the heating body at a predetermined temperature and at least one reference electric power are provided as means for determining the time for stopping or reducing the heat generation of the heating body, and the reference electric power is provided. 3. The time for stopping or reducing the heat generation of the heating body is provided when the detected power is higher or lower than that of the detected power, respectively.
The heating device according to. 6. A means for detecting the size of the material to be heated to be conveyed is provided as means for determining the time for stopping or reducing the heat generation of the heating element, and stopping or reducing the heat generation of the heating element according to the size of the material to be heated. The heating device according to claim 1, wherein each heating time is set. 7. As a means for determining the time to stop or reduce the heat generation of the heating body, the calorific value of the heating body is temporarily increased when there is no heated body at the position of the heating body, and the heating body The heating device according to claim 1, wherein the time for stopping or reducing the subsequent heat generation is determined based on the amount of temperature increase. 8. As a means for determining the time for stopping or reducing the heat generation of the heating body, between the next objects to be heated according to the rate of temperature rise when heating again after stopping or reducing the heat generation of the heating body. 2. The heating device according to claim 1, wherein the time for stopping or reducing the heat generation of the heating element is determined. 9. The heating device according to claim 1, wherein the heating device is an image heating and fixing device that heats and fixes an image on a recording material carrying an unfixed image. . 10. A heat resistant film is brought into contact with and slid on the heating body, a material to be heated is brought into close contact with the surface of the film opposite to the heating body, and the film is passed through the heating body position together with the film to remove the heat from the heating body. In a heating device for applying heat energy to a material to be heated through a film, it has a temperature detecting means for the heating body and means for energizing the heating body so that the temperature detected by the temperature detecting means is maintained at a constant temperature, When the material to be heated does not exist at the position of the heating body, the power supply to the heating body is stopped, and there is a heating body temperature control means for changing the control temperature of the heating body according to the temperature change of the heating body at that time, A heating device, wherein the time during which the energization time of the heating body is stopped is set to be longer than the time during which a temperature change of the heating body is detected. 11. A heat resistant film is brought into contact with and slid on the heating body, a material to be heated is brought into close contact with the surface of the film opposite to the heating body, and the film is passed through the heating body position together with the film to remove the heat from the heating body. In a heating device for applying heat energy to a material to be heated through a film, it has a temperature detecting means for the heating body and means for energizing the heating body so that the temperature detected by the temperature detecting means is maintained at a constant temperature, It has a heating body temperature control means for supplying constant power to the heating body when the material to be heated does not exist at the position of the heating body, and changing the control temperature of the heating body according to the temperature change of the heating body at that time. The heating device is characterized in that the time during which constant power is supplied to the heating body is longer than the time during which the temperature change of the heating body is detected at that time. 12. The heating device according to claim 10 or 11, wherein the heating device is an image heating and fixing device that heats and fixes an image on a recording material carrying an unfixed image. 13. A heat resistant film is brought into contact with and slid on the heating body, a material to be heated is brought into close contact with the surface of the film opposite to the heating body, and the film is passed through the heating body position together with the film to remove the heat from the heating body. In a heating device for applying heat energy to a material to be heated through a film, a temperature detecting means for the heating body and a means for energizing the heating body so that the temperature detected by the temperature detecting means is maintained at a constant temperature T _1. have the above together with the heating material to control the heating body to the temperature T ₁ of lower temperatures T'when not in the heating body position, within a predetermined time from the time of switching the control from the temperature T ₁ of the temperature T' follows when reaching a temperature T'control temperature of the heating element with respect to the heating member is set to T _1, the temperature T ₁ of the control temperature of the heating member for the next object to be heated when not reached within a predetermined time characterized by a lower temperature T ₂ Heat equipment. 14. A heat resistant film is brought into contact with and slid on the heating body, a material to be heated is brought into close contact with the surface of the film opposite to the heating body, and the film is passed together with the film through the position of the heating body to remove the heat from the heating body. In a heating device for applying heat energy to a material to be heated through a film, a temperature detecting means for the heating body and a means for energizing the heating body so that the temperature detected by the temperature detecting means is maintained at a constant temperature T _1. In addition, when the material to be heated is not present at the position of the heating body, the heating body is controlled to a temperature T ′ lower than the temperature T ₁ and the control temperature T ′ is reached from when the control temperature T ′ is reached. The time t until the time t is measured, and when the time t is longer than a predetermined time, the control temperature of the heating body for the next material to be heated is set to a temperature T ₂ lower than the temperature T ₁ , and the time t is a predetermined time or less. In case of Heating device and controls the control temperature of the heating body T _1. 15. The heating device according to claim 13 or 14, wherein the heating device is an image heating and fixing device that heats and fixes an image on a recording material carrying an unfixed image. 16. A heat resistant film is brought into contact with and slid on the heating body, a material to be heated is brought into close contact with the surface of the film opposite to the heating body, and the film is passed through the heating body position together with the film to remove the heat from the heating body. In a heating device that applies heat energy to a material to be heated through a film, when the object to be heated does not pass through the heating region of the heating device, power supply to the heating object is controlled by two values of High and Low, A heating device which determines a control temperature of the heating body for a material to be heated next entering a heating region based on a temperature ripple of the heating body at this time. 17. A heat-resistant film is brought into contact with and slid on the heating body, a material to be heated is brought into close contact with the surface of the film opposite to the heating body, and the film is passed through the heating body position together with the film to remove the heat from the heating body. In a heating device that applies heat energy to a material to be heated through a film, when the object to be heated does not pass through a heating region of the heating device, power supply to the heating object is controlled by two values of High and Low, A heating device which determines a control temperature of a heating body with respect to a material to be heated which enters a heating region next based on the temperature change rate at the time of High or Low. 18. A heat resistant film is brought into contact with and slid on the heating body, a material to be heated is brought into close contact with the surface of the film opposite to the heating body, and the film is passed through the heating body position together with the film to remove the heat from the heating body. In a heating device that applies heat energy to a material to be heated through a film, when the object to be heated does not pass through the heating region of the heating device, power supply to the heating object is controlled by two values of High and Low, A heating device characterized in that the control temperature of the heating element for the material to be heated next entering the heating region is determined based on the peak or bottom of the temperature ripple of the heating element at this time. 19. The heating device according to claim 16 or 18, wherein the heating device is an image heating and fixing device for heating and fixing an image on a recording material carrying an unfixed image. 20. A heating device having a heating body and a temperature detecting member for detecting the temperature of the heating body, and energizing the heating body so that the temperature detected by the temperature detecting member is kept constant at a predetermined temperature, The various control values thereafter are determined based on the temperature rising rate detected from the start of energization of the heating element until the temperature reaches the predetermined temperature, and the amount of electric power supplied to the heating element is within a unit time. The heating is characterized by having a means for controlling the ratio of energization / de-energization to the device and varying the ratio, and the detection time of the heating rate is set to a unit time of power control to the heating body or more. apparatus. 21. The heating device according to claim 20, wherein the detection time of the heating rate is an integral multiple of a unit time of electric power control to the heating body. 22. The film according to claim 20, further comprising a film that moves together with a recording material supporting the visible image, and the visible image is heated by heat from a heating body through the film. Heating device.