JPH06118838A - Heating device and image forming device - Google Patents

Abstract

PURPOSE:To prevent toe uneven heating or a material to be heated as for a heating device and to prevent the faulty fixing of the leading edge of a recording material as the material to be heated as for an image fixing device. CONSTITUTION:A heating body 21 energized so as to generate heat, and a heat resistant film carried into contact with the heating body 21 are provided, and the heat energy of the heating body 21 is given to the material to be heated through the film by bringing the material to be heated into contact with the surface of the film opposite to the heating body side and carrying it to pass the position of the heating body together with the film. This film on a side heating system heating device is provided with a control means 31 for controlling number of the half waves of AC power source impressed on the heating body 21 for a specified time, a detecting means 35 for detecting that the material to be heated reaches the heating device, and a means 33 for controlling impressed power impressed on the heating body 21 in accordance with the detected information by the means 35.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a heating body which generates heat when energized and a heat resistant film which is conveyed in contact with the heating body, and the surface of the film opposite to the heating side is heated. The present invention relates to a film heating type heating device that applies heat energy of a heating body to a material to be heated through the film by bringing the material into close contact with the film and conveying the material through the position of the heating body.

An image forming apparatus provided with the heating device as a fixing device for heating and fixing the carried image material image of a recording material as a material to be heated on which a heat-fixable image material image is formed and carried, For example, the present invention relates to an image forming apparatus such as a copying machine, a printer, or a fax machine that forms an image using a heat-fixing developer (toner).

[0003]

2. Description of the Related Art A heating device of the film heating type as described above has been proposed in, for example, JP-A-63-313182, JP-A-2-157878, and JP-A-2-339900. , Electrophotographic copiers / printers
An image heating and fixing device in an image forming apparatus such as a fax machine, for example, a recording material (electrofax sheet. A recording material carrying an unfixed image material image corresponding to the target image information formed on the surface of the electrostatic recording sheet, transfer material sheet, printing paper, etc. by a direct method or an indirect (transfer) method. It can be utilized as an image heating and fixing device that heats and fixes as a fixed image.

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

Conventionally, a heating device of a recording material for heating and fixing an image includes a heating roller maintained at a predetermined temperature,
A heat roller fixing method is widely used in which a recording material is sandwiched and heated by a pressure roller that has an elastic layer and is in pressure contact with the heating roller while heating. In addition, various methods such as flash heating method, oven heating method, hot plate heating method, etc.
The configuration is known and is in practical use.

A belt heating system is also known as disclosed in US Pat. No. 3,578,797.
this is, . Fusing the toner image by contacting it with a heating element web and heating it to its melting point; After fusing, the toner is cooled to a relatively high viscosity ,. It is a method of fixing without causing offset by passing through a process of peeling the toner from the heating body web in a state where the tendency of the toner to adhere to the heating body web is weakened.

Recently, as a film heating type heating device (fixing device) as described above, a fixedly supported heating member (thermal heater, hereinafter referred to as a heater) and a heat-resistant member that is conveyed while being pressed against the heater. The recording material has a pressurizing member that brings the recording material into close contact with the heater through the flexible film, and the heat of the heater is applied to the recording material to form an unfixed image on the surface of the recording material. An apparatus having a system and a configuration for heating and fixing on a paper has been devised.

For example, the method and apparatus disclosed in Japanese Patent Laid-Open No. 63-313182 belong to this, and include a thin heat-resistant film (sheet), a moving driving means for the film, and the film inside. A heater fixedly supported on one side is closely attached to a heater on the other side, which is opposed to the heater, and the image bearing surface of the recording material of the recording material on which the image is to be fixed through the film. The film has a pressurizing member, and at least during image fixing, the film is moved between the film and the pressurizing member in the forward direction at the same speed as the recording material to be image-fixed. The developer material image-bearing surface of the recording material is heated by the heater through the film by passing through a fixing nip portion as a fixing point formed by pressure contact between a heater and a pressure member with a moving film interposed therebetween. Manifest Zaizo (unfixed toner image) the thermal energy imparted allowed softened and melted in, then a heating means or apparatus which is based on that are spaced from each other by a separation point of the recording material and the film after fixing points pass.

In such a film heating system,
A low heat capacity heating element can be used as the heater.
Therefore, it is possible to save power and shorten the wait time (quick start) as compared with the conventional contact heating method such as the heat roller method and the belt heating method. Other,
Has the advantage of being able to solve various drawbacks of conventional heating methods,
It is effective.

[0010]

By the way, in the above-mentioned film heating type heating device or fixing device, since a low heat capacity heater is used, if excessive power is applied, the temperature rises excessively and the heater is damaged. , Overshoot becomes large. On the other hand, if the electric power is too small, the temperature may not reach a predetermined heating (fixing) temperature, or the temperature may drop quickly and the temperature ripple may increase.

Therefore, it is necessary to finely control the electric power for the heater, and an AC phase control method and a DC-PWM control method have been proposed as the electric power control method.

However, the AC phase control method has a problem that a large noise is periodically generated, and the DC-PWM control method has a complicated control circuit.

Therefore, a wave number control method has been proposed in which control is performed from the zero point of the AC power source to the next zero point as a basic unit.

(A) However, in the conventional film heating type heating device (fixing device), the material to be heated (recording material, paper) is heated by the low heat capacity heater via the heat-resistant film, so that the heater generates heat. When not being heated, the temperature of the heater sharply drops when the material to be heated passes, and as a result, when the heater is not generating heat, it does not heat, that is, uneven heating (fixing unevenness) occurs.

With respect to the image fixing device, since heat transfer through the recording material cannot be expected at the leading end of the recording material as the material to be heated (the recording material is conveyed by the fixing device, the direction of heat transfer is the time axis). Direction occupies most), and the image fixability is significantly impaired at the leading end of the recording material.

In this case, if the fixing property of the leading end of the recording material is set to the electric power applied to the heater, the fixing property does not cause any problem at the leading end of the recording material, but at this time, the developing material is over-melted in other areas, causing offset or the like. .

A first object of the present invention is to prevent the above-mentioned heating unevenness and the above-mentioned defective fixing of the leading end of the recording material in the image fixing apparatus.

(B) Also, when the wave number control method is adopted as the electric power control method for the heater, the wave number control method applies voltage to the heater even if the combination of half-waves in the control unit is the same. The amount of electric power applied varies depending on the state of the AC power source, and as a result, the desired electric power cannot be obtained, which may adversely affect the stability of the image formed in the fixing device or the image forming apparatus. It was

In order to compensate for this, there has been proposed a means for changing the number of half-wave outputs within a predetermined control time according to the state of the AC power source to change the electric power applied to the heater, but the electric power is switched at a predetermined time. Since it can be done only in half wave units within the control time of, it is not possible to absorb the fluctuation of electric power sufficiently,
As a result, there is a problem in that the accuracy of power switching becomes poor.

Therefore, according to the present invention, the accuracy of switching the applied power is increased to make it easy to obtain the desired power, and stable heat processing and stable and good heat fixing processing without fixing unevenness in the image fixing device are executed. The second purpose is to do so.

(C) In the wave number control method, depending on the combination of half-waves in the control unit, for example, the number of control blocks is 4 and the power supply voltage of the AC power supply is 10 as shown in FIG.
When using a heater of 0 V, constant frequency, heating element resistance value of 10 Ω and 1000 W output, and controlling at 750 W, when controlling so that only 3 waves are energized in the control block unit, the AC power consumption is positive. Or it will be negatively biased. As a result, in the case of energizing a device that consumes a relatively large amount of power as in this example, a direct current component appears on the AC line, and the transformer on the power supply line is magnetized by direct current or on the same line. This will have an unfavorable effect on other connected devices.

Therefore, the present invention eliminates the positive or negative biased power consumption of the alternating current, and enables stable use of the device without adversely affecting external devices or parts inside the main body. Is the third purpose.

(D) Further, in the wave number control method, since the electric power is controlled by the combination of half waves within the control unit, the non-energized section becomes large depending on the electric power value applied to the heating body. For example, as shown in FIG. 26, the number of control blocks is 10 and the power supply voltage of the AC power supply is 100.
V, frequency 50Hz constant, heating resistance value of heater is 10
When a Ω heater is used, except when the power is completely turned off, the output is 1 / 10th, 90m continuously.
During s, there is a non-energized section.

On the other hand, when the recording material conveying speed of the image forming apparatus using this low heat capacity heater is 100 mm / sec,
The recording material is conveyed by 9 mm in 0 ms. That is up to 9
During the period of mm, the recording material is not subjected to electric heating from the heater.

Further, as shown in FIG. 27, heat transfer through the recording material cannot be expected at the leading end of the recording material (since the recording material is conveyed by the fixing device, the direction of heat transfer is the direction of the time axis t). In most cases, the image fixing property is significantly impaired at the leading edge of the recording material.

Therefore, according to the present invention, uneven heating of the material to be heated is prevented from occurring in the section where the heating body is not energized, and in the image fixing device, the fixing failure is prevented even at the leading end of the recording material. A fourth object is to perform a stable heat fixing process over the entire area of the recording material.

[0027]

DISCLOSURE OF THE INVENTION The gist of the present invention is a heating device having the following constitution or an image forming apparatus using the heating device as an image fixing device.

(1) A film having a heating body that generates heat when energized and a heat resistant film that is conveyed in contact with the heating body, and a material to be heated is adhered to the side surface of the film opposite to the heating body side. In a heating device of a film heating system that applies heat energy of a heating body to a material to be heated through a film by conveying and passing the heating body together, a half of an AC power source applied to the heating body within a predetermined time. It has a control means for controlling the number of waves, a detection means for detecting that the material to be heated reaches the heating device, and a means for controlling the electric power applied to the heating body according to the detection information of the detection means. A heating device characterized by the above.

(2) According to the detection information of the detection means,
Applied power before and after the heated material reaches the heating device 1
And applied power 2 at other times, applied power 1
> The heating device according to (1), further comprising control means for controlling the applied power to be 2.

(3) According to the detection information of the detection means,
The heating device according to (1), further comprising a control unit that controls the predetermined time.

(4) According to the detection information of the detection means,
The heating device according to (1), wherein the number of half-waves of an AC power source applied to the heating element within the predetermined time is controlled.

(5) The heating device according to any one of (1) to (4), wherein the predetermined time is a positive multiple of one half of the AC power supply cycle applied to the heating element.

(6) The carried developing material image of a recording material as a material to be heated, on which the heating device according to any one of (1) to (5) above is formed and carried a heat fixing property developing material image. An image forming apparatus provided as a fixing device for heating and fixing to a recording material.

(7) A heating body that generates heat when energized and a heat-resistant film that is conveyed in contact with the heating body are provided, and a material to be heated is brought into close contact with the film on the side opposite to the heating body side of the film. In a heating device of a film heating system that applies heat energy of a heating body to a material to be heated through a film by conveying and passing the heating body together, a half of an AC power source applied to the heating body within a predetermined time. A heating device comprising: a control means for controlling the number of waves; a detection means for detecting resistance value information of the heating body; and a means for varying the predetermined time period according to a detection signal of the detection means. .

(8) The heating device according to (7), wherein the resistance value information is resistance value information of the heating element at room temperature.

(9) The heating device according to (7), wherein the resistance value information is resistance value information that changes with a temperature change of the heating body. (10) The heating device according to any one of (7) to (9), wherein the predetermined time is a positive multiple of ½ of an AC power supply cycle applied to the heating body. (11) The heating device according to any one of (7) to (10) is used as a recording material, the recording material image being a recording material as a material to be heated on which a heat-fixable developing material image is formed and supported. An image forming apparatus provided as a fixing device for heating and fixing. (12) It has a heating body that is heated by energization and a heat resistant film that is conveyed in contact with the heating body, and a material to be heated is brought into close contact with the side opposite to the heating body side of the film and heated together with the film. In a film-heating-type heating device that applies heat energy of a heating body to a material to be heated through a film by transporting the body position, the number of half-waves of an AC power source applied to the heating body within a predetermined time. A heating device comprising: a control means for controlling the number of half-waves output within the predetermined time, a counting means for counting the number of half waves output within the predetermined time, and a means for changing the control pattern within the predetermined time according to the count value. (13) The predetermined time is a positive multiple of one half of the AC power supply cycle applied to the heating element (1
The heating device according to 2). (14) The heating device according to the above (12) or (13) heat-fixes the carried developing material image of a recording material as a heated material on which a heat-fixable developing material image is formed and carried. An image forming apparatus provided as a fixing device. (15) A heating element that generates heat when energized and a heat-resistant film that is conveyed in contact with the heating element are provided, and a material to be heated is adhered to the side surface of the film opposite to the heating element side and heated together with the film. In a film-heating-type heating device that applies heat energy of a heating body to a material to be heated through a film by transporting the body position, the number of half-waves of an AC power source applied to the heating body within a predetermined time. A heating device comprising: a control means for controlling the heating means and a means for controlling the heating material so as to coincide with the energized portion in the control pattern within the predetermined time at a timing when the material to be heated plunges into the heating body. (16) At the timing when the tip of the material to be heated rushes into the heating body, control means for controlling the tip of the material to be heated to match the energized portion in the control pattern within the predetermined time. The heating device according to (15), characterized in that it has a detection means for detecting the timing of the entry, and changes the control pattern within the predetermined time in accordance with the detection signal of the detection means. . (17) At the timing when the tip of the material to be heated rushes into the heating body, the control means for controlling the heating material to rush into the heating body so as to coincide with the energized portion in the control pattern within the predetermined time. (15) The heating device according to (15), characterized in that the control is delayed according to a pattern for controlling the timing. (18) The predetermined time is a positive multiple of one half of an AC power supply cycle applied to the heating body (1)
The heating device according to any one of 5) to (17). (19) By using the heating device according to any one of (15) to (18) above, the recording material image of the recording material as the material to be heated on which the image material material of the heat fixing property is formed and supported is used as the recording material. An image forming apparatus provided as a fixing device for heating and fixing.

[0037]

(A) A half-wave of an AC power supply applied to a heating body within a predetermined time, as in the heating device of (1) to (6) or an image forming apparatus including the heating device as a fixing device The heating device is provided with a detection means for detecting that the material to be heated reaches the heating device, and when the material to be heated reaches the heating device in accordance with the detection information of the detection means, it is applied to the heating body. By increasing the electric power to be applied, it is possible to prevent heating failure of the tip end portion of the material to be heated, and in the fixing device of the image forming apparatus, it is possible to prevent fixing failure of the tip end portion of the recording material. Can be reached.

(B) As in the heating device of (7) to (11) or an image forming apparatus having the heating device as a fixing device, the heating member is energized within a predetermined time. Having a control means for controlling the number of half-waves of the applied AC power supply, and having a detection means for detecting resistance value information of the heating body,
By having the control means for controlling the predetermined time according to the detection signal of the detection means, the accuracy of switching the applied power is increased, so that the desired power can be easily obtained, and the stable heat treatment and image forming apparatus can be performed. In the fixing device, a stable heat fixing process can be executed, and by using a low heat capacity heating element having this temperature control means, the switching accuracy of the amount of electric power required for the heat process / fixing process increases,
Since stable heating / fixing processing is performed without wasting unnecessary power, it is possible to contribute to power and energy saving of the apparatus, and the second object can be achieved.

(C) As in the heating device of (12) to (14) or an image forming apparatus equipped with the heating device as a fixing device, the heating member is energized within a predetermined time. Control means for controlling the number of half-waves of the AC power source to be applied, and coefficient means for counting the number of half-waves output within the predetermined time, and the control pattern within the predetermined time by this coefficient value By having a means for changing the power consumption, the power consumed by controlling the energization of the heating element does not deviate to the positive side or the negative side, so it does not adversely affect external equipment or parts inside the main unit, and it is stable The device can be used, and the third purpose can be achieved.

(D) As in the case of the heating device of (15) to (19) or an image forming apparatus equipped with the heating device as a fixing device, the heating device is energized within a predetermined time. It has a control means for controlling the number of half-waves of the applied AC power source, and a detection means for detecting the timing at which the tip of the recording material rushes into the heating body, and according to the detection signal of this detection means, By having the means for changing the control pattern within the predetermined time, it is possible to prevent uneven heating of the material to be heated due to a section where the heating body is not energized, and in the fixing device, fixing is performed even at the leading end of the recording material. The fourth object can be achieved in which a defect is prevented from occurring and a stable heat fixing process is executed over the entire area of the recording material.

[0041]

EXAMPLES A. The following first and second embodiments are embodiments of an image forming apparatus including a heating device or a fixing device including the heating device, which has the configuration described in claims 1 to 6 of the claims. Is.

<First Embodiment> (FIGS. 1 to 8) (1) Example of Image Forming Apparatus (FIG. 1) FIG. 1 is a schematic view of an example of an image forming apparatus equipped with a film heating type heating device as a fixing device. It is a block diagram. The image forming apparatus of this example is a reciprocating platen / rotating drum type / transfer type electrophotographic copying apparatus.

Reference numeral 100 denotes an apparatus casing, and 1 denotes a reciprocating type document placing table made of a transparent plate member such as a glass plate disposed on an upper surface plate 100a of the apparatus casing.
The upper part is driven to reciprocate to the right a and the left a'in the drawing at a predetermined speed.

Reference numeral G denotes an original document, which is placed on the upper surface of the original document table 1 with the image surface side to be copied facing downward according to a predetermined placement standard, and the original document pressure plate 1a is placed on the original document platen 1a and pressed down. Set.

Reference numeral 100b denotes a slit opening serving as a document illuminating section which is opened on the surface of the machine top plate 100a with a direction perpendicular to the reciprocating direction of the document placing table 1 (direction perpendicular to the paper surface) as a longitudinal direction.

The downward image surface of the document G placed and set on the document placing table 1 is sequentially subjected to the slit opening 10 from the right side to the left side in the forward movement process of the document placing table 1 to the right a.
The light L of the fluorescent lamp 3 is received through the slit opening 100b and the transparent document placing table 1 and is illuminated and scanned while passing through the position 0b. The light reflected from the document surface of the illumination scanning light is image-wise exposed on the surface of the photosensitive drum 4 by the short-focus small-diameter image-forming element array 2.

The photosensitive drum 4 is coated with a photosensitive layer such as a zinc oxide photosensitive layer, an organic semiconductor photosensitive layer, and the like.
Shown at a predetermined process speed (peripheral speed) around a
Is rotated clockwise, and in the course of the rotation, a uniform charging process of positive or negative polarity is performed by the charger 5, and the imagewise exposure (slit exposure) of the original image is performed on the uniformly charged surface.
As a result, the electrostatic latent image corresponding to the original image image-formed and exposed is sequentially formed on the surface of the photosensitive drum 4.

This electrostatic latent image is successively visualized by a developing device 6 with toner made of resin or the like which is softened and melted by heating,
The toner image, which is the visible image, moves to a portion where the transfer discharger 9 as a transfer portion is provided.

Reference numeral S denotes a cassette in which transfer material sheets P as recording materials are stacked and housed, the sheets in the cassette are fed out one by one by the rotation of the feeding roller 7, and then the registration roller 8 causes the drum 4 to move. When the tip of the upper toner image forming portion reaches the portion of the transfer discharger 9, the tip of the transfer material sheet P also arrives at the position between the transfer discharger 9 and the photosensitive drum 4, and the timing is adjusted so that they coincide with each other. It is then delivered synchronously. Then, the transfer discharger 9 sequentially transfers the toner images on the photosensitive drum 4 side to the surface of the fed sheet.

The sheet to which the toner image has been transferred at the transfer portion is sequentially separated from the surface of the photosensitive drum 4 by a separating means (not shown), and is guided by a conveying device 10 to a fixing device 11 which will be described later. The image is heated and fixed, and is discharged as an image-formed product onto the discharge tray 12 outside the machine through the guide 43 and the discharge roller 44.

The surface of the photosensitive drum 4 after the image transfer is subjected to removal of adhering contaminants such as transfer residual toner by the cleaning device 13 and is repeatedly used for image formation.

(2) Fixing Device 11 (FIGS. 2 and 3) FIG. 2 is a schematic configuration diagram of the fixing device 11. FIG. 3 is a plan view in which an intermediate part of the heating element (heater) is viewed from the side where the energized heating element layer is formed.

Reference numeral 25 denotes a heat-resistant fixing film in the form of an endless belt, which has a left driving roller 26, a right driven roller 27, and a low heat capacity fixedly supported below both rollers 26, 27. The heater 21 as a linear heating element and a guide roller 26a arranged below the drive roller 26 are arranged in parallel with each other by the four members 26.
Suspended between 27, 21 and 26a.

The driven roller 27 also serves as a tension roller for the endless belt-shaped fixing film 25.
The fixing film 25 is a recording material having an unfixed toner image Ta conveyed from the image forming section (9) side on the upper surface thereof at a predetermined peripheral speed in the clockwise direction with the clockwise rotation of the driving roller 26. The transfer material sheet P is rotationally driven at the same peripheral speed as the conveying speed of the transfer material sheet P without wrinkles, meandering, or speed delay.

Numeral 28 is a pressure roller as a pressure member having a rubber elastic layer having a good releasability such as silicon rubber, and sandwiching the film portion on the descending side of the endless belt-shaped fixing film 25, and the heater. The lower surface of the sheet 21 is pressed against the lower surface of the sheet 21 by urging means with a contact pressure of, for example, 4 to 7 kg in total, and rotates in the forward counterclockwise direction in the transport direction of the transfer material sheet P.

Since the fixing film 25 in the form of an endless belt which is rotationally driven is repeatedly subjected to heat fixing of a toner image, it has excellent heat resistance, releasability and durability, and generally has a total thickness of 100 μm or less, Preferably, a thin monolayer or composite layer film of less than 40 μm is used.

In this embodiment, polyimide, polyether imide, PES, PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin) or the like is used to form a PT on the image contact surface side of a heat resistant resin film having a thickness of about 20 μm.
A release coating layer such as FE (tetrafluoroethylene resin) / PAF is applied to a thickness of about 10 μm.

As the heater 21 as the heating body, in this example, the heater substrate 22 having insulation, high heat resistance, and low heat capacity whose longitudinal direction is in the direction orthogonal to the transfer material sheet P conveying direction is used.
And a heater temperature detecting element provided by contacting an energization heating element layer 23 formed by printing along the length of the substrate surface and a surface of the substrate 22 opposite to the energization heating element layer formation surface side. The basic structure of the thermistor 24 is of low heat capacity, and the heater 21 is held in the heater holder 30 by exposing the side of the surface where the electric heating element layer is formed.

The heater holder 30 holds the heater 21 adiabatically, and is made of a high heat-resistant resin such as PPS (polyphenylene sulfide), PAI (polyamide imide), PI (polyimide), PEEK (polyether ether ketone), and liquid crystal polymer. Or a composite material of these resins and ceramic metal, glass, or the like.

The heater substrate 22 has a thickness of 1.0 as an example.
It is an alumina substrate having a size of 10 mm, a width of 10 mm, and a length of 270 mm. Further, it is a composite material substrate including the same.

As shown in FIG. 3, the energization heating element layer 23 is formed along the longitudinal direction on the lower surface of the heater substrate 22 in a substantially central portion, for example, Ag.
/ Pd, an electrical resistance material such as RuO _2, Ta ₂ N width 2.
A power supply electrode 23a.2 provided by applying (screen printing, etc.) to 0 mm and energizing both ends thereof.
A voltage is applied between 3b to energize.

The energization is controlled by the temperature detecting element 24, and the energy temperature of the heater 21 is controlled by applying electric power according to the desired amount of temperature energy emission.

The surface of the heater 21 on which the electric heating layer 23 is formed may be covered with a surface protective layer such as thin heat-resistant glass in order to prevent abrasion of the film 25 due to sliding conveyance.

(3) Fixing Execution Operation The transfer material sheet P conveyed from the image forming portion (9) side to the fixing device 11 is guided by the entrance guide 29 by the image forming device performing an image forming operation in response to the image forming start signal. , A pressure contact portion N between the temperature controlled heater 21 and the pressure roller 28.
(Fixing nip portion) fixing film 25 and pressure roller 2
8 in which the unfixed toner image surface moves in the same direction at the same speed as the sheet P conveyance speed.
The film 5 passes through the fixing nip portion N between the heater 21 and the pressure roller 28 while receiving a nipping pressure in close contact with the lower surface of the sheet 5 without causing surface deviation or wrinkling.

A sheet sensor 35 is provided in the entrance guide 29 and detects when the leading edge of the sheet reaches the fixing device 11.

The toner image bearing surface of the sheet P receives the heat of the heater 21 through the film 25 in the process of passing through the fixing nip portion N while being pressed against and in close contact with the film surface, and the toner image is melted at a high temperature and the sheet P is heated. The surface is softened and adhered to Tb.

In the case of the apparatus of this example, the sheet P as a recording material and the film 25 are separated from each other when the sheet P passes through the fixing nip portion N and comes out.

The sheet P separated from the film 25 is guided by the guide 43, and the temperature of the toner Tb higher than the glass transition point is naturally lowered (natural cooling) while reaching the pair of discharge rollers (44). The temperature below the point is reached and solidification Tc is reached, and the sheet P on which the image has been fixed is output onto the tray.

FIG. 4A is a perspective view of an example of a fixing device in which the guide roller 26a is omitted in the fixing device of FIG. The film 25 is not limited to the endless belt shape, and as shown in FIG. 4B, the end fixing film 25 wound around the delivery shaft 41 in a roll winding is provided between the heater 21 and the pressure roller 28, and the guide roller 26a. It may be configured so as to be engaged with the take-up shaft 42 via the lower side and run at the same speed as the conveyance speed of the transfer material sheet P from the delivery shaft 41 side to the take-up shaft 42 side.

(4) Heater power control circuit (FIGS. 5 and 6) FIG. 5 is a block diagram of the heater power control circuit of this embodiment.

Reference numeral 34 is an AC power supply means. Reference numeral 31 is a control means, which in the present embodiment is constituted by a microcomputer, a logic element and the like. The output value of the thermistor 24 as a temperature detecting element of the heater 21 is input to the input terminal IN1 of the control means 31.
The temperature of is being detected.

Reference numeral 32 denotes a zero point detecting means for detecting the zero voltage timing of the AC power source 34, and the zero point detecting means 3
The output of 2 is input to the input IN2 of the control means 31, and the control means 31 follows the signal of IN2 to the heater 21.
It outputs the signal of the energization control of.

The sheet sensor 35 is connected to the input terminal IN3 of the control means 31, and the control means 31 uses the signal of the sensor 35 to feed the leading edge of the sheet to the fixing device 11.
It detects that it has reached.

Reference numeral 33 is an energization control device (energization control means), which is composed of switch means such as a triac. The heater 21 is energized according to the output signal of the control means 31.

The control means 31 is connected to other inputs and outputs for controlling the copy sequence of the image forming apparatus. Further, a ROM and a RAM in which a copy operation sequence program and the like are programmed are built in.

A + 5V DC power source is connected to the V _CC terminal, and the GND terminal is connected to the ground.

The energization control of the heater 21 is energized with the minimum unit from the zero point of the AC power source 34 to the next zero point, and the predetermined number of blocks of the wave from the zero point to the next zero point as the control block unit. .

The power applied to the heater 21 is controlled by controlling the number of energized waves between the control block units.
For example, when the control block unit is 8 waves and a heater of 1000 W is used with AC100 V input, and when controlling 500 W, the control block unit is controlled so that only 4 waves are energized. When the control block unit is 10 waves, it is controlled so that only 5 waves are energized.

An example thereof is shown in FIG. 6A shows the case where the control block unit is 8 waves, and FIG. 6B shows the case where the control block unit is 10 waves. The shaded waves are the energized waves. The minimum power unit to be controlled by the wave number of the control block is determined. In the above heater example, the control block can be controlled in the unit of 8 waves in 125 W units, and in the control block in the 10 units of 100 W units. is there.

In this embodiment, the control block unit is usually 1
It is assumed to be controlled by 0 wave.

(5) Energization control flow (FIGS. 7 and 8) FIG. 7 is a part of the energization control flow of the control means 31. This subroutine is a routine called for each zero point of the AC power source.

In step S1, it is checked whether copying is in progress. When copying is not in progress, the process proceeds to step S2, the control counters 1 and 2 are cleared, the heater (heating body) 21 is deenergized, and the process exits to the exit.

When the copy operation is started, the process proceeds to step S3. In step S3, it is checked whether the control counter 1 is zero. The control counter 1 is a buffer counter for each control block. When it is not zero in step S3, the process proceeds to step S8. When it is zero in step S3, the process proceeds to step S4.

In step S4, it is checked whether the paper (sheet) front end flag is "1". This paper leading edge flag is a flag that is set in another routine, and becomes "1" for a predetermined time when the paper leading edge enters the fixing device 11. When it is not "1" in step S4, the process proceeds to step S6. At this time, the control counter 1 has a normal control block unit of 10
Is set and the process proceeds to step S7. When the value is "1" in step S4, the process proceeds to step S5.

In step S5, the control counter 1 is set to 5, which is half of the control block unit, and step S7 is executed.
Move to.

In step S7, the number of energized waves within a single control block stored in advance at a predetermined address is set in the control counter 2, and the process proceeds to step S8.

In step S8, the control counter 1 is decremented by 1, and the process proceeds to step S9.

In step S9, it is checked whether the control counter 2 is zero. Exit to the exit when zero. Step S
When it is not zero in step 9, the process proceeds to step S10.

In step S10, only one wave is energized, the process proceeds to step S11, the control counter 2 is decremented by 1 in step S11, and the process exits to the exit.

Next, the setting and resetting of the paper leading edge flag will be described with reference to FIG. FIG. 8 shows a subroutine that is called at regular time intervals or as needed.

In step S12, it is checked whether copying is in progress. When copying is not in progress, the process proceeds to step S14,
Reset the paper edge flag and edge flag and exit to the exit.

If copying is in process in step S12, the process proceeds to step S13.

In step S13, it is checked whether the sheet sensor 35 at the entrance of the fixing device is ON. When it is not ON, the process proceeds to step S15.

In step S15, the edge flag is reset and the process exits to the exit.

When the sensor 35 is ON in step S13, the process proceeds to step S16.

In step S16, it is checked whether the edge flag is "1". This edge flag is a flag used to determine the leading edge of the paper. Step S1
When it is not “1” in 6, the process proceeds to step S18.

In step S18, the edge flag is set, the timer is started, and the process exits to the exit.

When it is "1" in step S16, step S1
Move to 7.

In step S17, it is checked whether the paper leading edge flag is "1". When it is not "1" in step S17, the process proceeds to step S21.

In step S21, the timer value is t ₁
Check whether or not If it is not t ₁ , exit to the exit. If t _1, the process proceeds to step S22. Where t ₁
Is a time shorter than the time required for the paper to move from the position of the sensor 35 to the fixing nip by the time of a control block unit.

In step S22, the paper leading edge flag is set, the timer is cleared and restarted, and the process exits to the exit.

When the paper leading edge flag is "1" in step S17, the process proceeds to step S19.

In step S19, the value of the timer is t ₂
Check whether or not Exit to the exit when it is not t ₂ . If t _2, the process proceeds to step S20. Where t ₂
Is the time in control block units. In step S20, the paper leading edge flag is reset, the timer is cleared and stopped, and the process exits to the exit.

As described above, the sheet sensor 35 at the entrance of the fixing device determines the timing at which the paper (sheet) enters the fixing device, and the electric power applied to the heater when the leading edge of the paper is accommodated is made larger than in other areas. Eliminates poor fixing at the leading edge of the paper. The sheet sensor 35 is the registration roller 8
The same can be done anywhere from to the fixing nip of the fixing device 11.

<Second Embodiment> (FIG. 9) In this embodiment, the energization control for the heater in the first embodiment is performed at the ON timing of the registration roller 8 instead of the signal of the sheet sensor 35 at the entrance of the fixing device. . The other structure is similar to that of the first embodiment.

The sheet P fed from the cassette S is synchronized with the image on the photosensitive drum 4 by the registration roller 8 for synchronization.
It stops once when it is struck by. After that, the rotation driving of the registration rollers 8 is started at the timing of synchronization.

FIG. 9 shows the setting of the paper leading edge flag of this embodiment,
It is a reset subroutine, which is called at regular time intervals or as needed.

It is checked in step S31 if copying is in progress. When copying is not in progress, the process proceeds to step S33,
Reset the paper edge flag and edge flag and exit to the exit.

If the copying is being performed in step S31, the process proceeds to step S32. In step S32, it is checked whether the driving of the registration roller 8 is ON. If not ON, the process proceeds to step S34.

In step S34, the edge flag is reset and the process exits to the exit.

When the driving of the registration roller 8 is ON in step S32, the process proceeds to step S35.

In step S35, it is checked whether the edge flag is "1". This edge flag is a flag used to determine the ON edge of the registration roller 8. When it is not "1" in step S35, the process proceeds to step S37.

In step S37, the edge flag is set, the timer is started and the process exits.

When the value is "1" in step S35, step S3
Go to 6. In step S36, it is checked whether the paper leading edge flag is "1". When it is not "1" in step S36, the process proceeds to step S40.

In step S40, the value of the timer is t ₃
Check whether or not exit to the outlet when not in t _3. If t _3, the process proceeds to step S41. Where t ₃
Is a time shorter than the time required for the paper to move from the position of the registration roller 8 to the fixing nip by the time of a control block unit.

In step S41, the paper leading edge flag is set, the timer is cleared and restarted, and the process exits to the exit.

When the paper leading edge flag is "1" in step S36, the process proceeds to step S38.

In step S38, the timer value is t ₂
Check whether or not Exit to the exit when it is not t ₂ . If t _2, the process proceeds to step S39. Where t ₂
Is the time in control block units.

In step S39, the paper leading edge flag is reset, the timer is cleared and stopped, and the process exits to the exit.

<Third Embodiment> (FIGS. 10 and 11) In this embodiment, the number of energizing waves is controlled for each control block. The other structure is similar to that of the first embodiment.

FIG. 10 shows the energization control subroutine of this embodiment. This subroutine is a routine called for each zero point of the AC power source.

It is checked in step S51 if copying is in progress. When copying is not in progress, the process proceeds to step S52, the control counters 1 and 2 are cleared, the heater 21 is de-energized, and the process exits to the exit. When the copy operation is started, the process proceeds to step S53.

In step S53, it is checked whether the control counter 1 is zero. The control counter 1 is a buffer counter for each control block.

When it is not zero in step S53, the process proceeds to step S55. When it is zero in step S53, step S
Move to 54.

In step S54, the control counter 1 is set to 10 which is a normal control block unit, and the control counter 2 is set to the number of energized waves in the control block unit stored in advance at a predetermined address. Step S
Move to 55.

In step S55, the control counter 1 is decremented by 1, and the process proceeds to step S56. In step S56, it is checked whether the control counter 2 is zero. Exit to the exit when zero.

When it is not zero in step S56, the process proceeds to step S57.

In step S57, only one wave is energized and the process proceeds to step S58. In step S58, the control counter 2 is decremented by 1 and the process exits to the exit.

Next, FIG. 11 shows a subroutine for determining the conduction wave number. This subroutine is at regular intervals
Or it is a subroutine called when necessary.

In step S59, the temperature of the heater is read by the thermistor 24.

In step S60, the number of energized waves is determined according to the heater temperature stored in advance at a predetermined address. This value is stored in the above-mentioned predetermined address used in the flow of FIG.

Then, in step S61, it is checked whether the paper leading edge flag is "1". If it is not "1" in step S61, exit to the exit. When the value is "1" in step S61, the process proceeds to step S62.

In step S62, the conduction wave number stored in the above-mentioned predetermined address is doubled and stored.

Here, the paper leading edge flag is set and reset by the subroutine shown in FIG. 8 similarly to the first embodiment. As in the above-described first to third embodiments, the timing at which the paper enters the fixing device is determined, and the power applied to the heater at the time of handling the front end of the paper is set to be larger than that in other areas, so that the front end of the paper is fixed. You can eliminate defects.

B. The following fourth and fifth embodiments are embodiments of an image forming apparatus having a heating device characterized by the construction described in claims 7 to 11 of the above claims or a fixing device including the heating device. is there.

The structure of the image forming apparatus shown in FIG.
The structure of the fixing device shown in FIG. 3 is the same in the fourth and fifth embodiments.

<Fourth Embodiment> (FIGS. 12 to 15) FIG. 12 is a block diagram of a heating body power control circuit of this embodiment.

Reference numeral 36 is a setting section for setting the resistance value of the heating element (heater) 21 at room temperature. When the image forming apparatus is assembled, the heating element resistance value is measured under a predetermined condition. Based on the result, it is set by means such as a DIP switch.

The heating element resistance value setting unit 36 is connected to the input terminal 1N4 of the microcomputer 31 as a control means.

The other circuit configuration is the same as that of the circuit shown in FIG.

The energization control of the heating body 21 is energized with the minimum unit between the zero point of the AC power source and the next zero point, and the predetermined number of blocks of the wave between the zero point and the next zero point as the control block unit. . The number of energized waves between control block units is controlled to control the electric power applied to the heating body 21.

For example, the control block unit is 8 waves, the power supply voltage of the AC power supply is 100 V, the frequency is constant, and the resistance value of the heating element (heating element) is 10 Ω. At this time, control is performed so that only four waves are energized in the control block unit.

That is, when the control block unit is 10 waves, control is performed so that only 5 waves are energized. An example thereof is shown in FIG. (A) is a case where the control block unit is 8 waves,
(B) is a case where the control block unit is 10 waves. The shaded waves are the energized waves.

The minimum power unit to be controlled by the wave number in the control block unit is determined, and in the above heating body example, the control block unit can be controlled in 125 W units for 8 waves, and in the control block unit for 10 waves in 100 W units. It is controllable.

14 and 15 show flowcharts of the heating body temperature control program of this embodiment. This program is also programmed in the built-in ROM in the microcomputer 31 as the control means described above.
The flow of the program shown in FIG. 5 is designed to be executed at regular time intervals or when called by a main sequence program or the like as needed.

In FIG. 14, in step 1 after turning on the main power switch of the apparatus, the microcomputer 31 performs a series of apparatus initialization operations such as initialization of the RAM.

In step 2, the micro computer 3
1 reads the resistance value of the heating body 21 at room temperature from the heating body resistance value setting unit 36 connected to 1N4.

Then, in step 3, the control unit of wave number is determined by the resistance value read in step 2.

Here, when the control unit is determined, it may be calculated by a certain relationship with the resistance, or may be stored as table data in the ROM. In addition, the upper limit value or the lower limit value or both are specified in the control unit,
The control unit may be determined within the range.

In FIG. 15, first, in the step 11 after entering the heating body control routine, the thermistor 24 outputs 1
The current temperature of the heating element 21 is detected by the signal input to N1.

In step 12, it is judged whether or not the temperature of the heating element 21 detected in step 11 deviates from a predetermined range when the device is operating normally, and it is normal. When it is judged that step 1
If it is determined that the process is not normal, the process proceeds to step 20.
Move to.

Here, step 20 is a routine for error processing, which is an endless loop in which all outputs of all devices (copiers in this embodiment) are turned off and an error is displayed with some display means. And prevents the main program from running.

At step 13, the zero-point detector 32 outputs 1
The zero point of the AC power source is detected by the signal input to N2, and if the zero point is not detected, the loop exits to the exit of this loop. When the zero point is detected, the process proceeds to step 14 to control the energization of the heating element.

In step 14, each time the zero point of the alternating current is detected, a signal is output from the OUT1 terminal to the energization controller 33 in accordance with the order of the combination of wave numbers previously determined in step 16 of this routine to send the signal to the heating element 21. Energize or stop energizing.

In step 15, it is judged whether or not the last control of the control unit determined in step 3 is finished. If it is in the middle of the control unit, the routine exits to this routine, and the last control of the control unit is finished. If so, the process proceeds to step 16, and the combination of wave numbers is determined so that a desired amount of power can be obtained in the control unit determined in step 3.

At this time, the wave number may be calculated by a desired applied power amount and calculation by a certain function, or may be stored as table data in the ROM.

After the above processing is completed, the heating body control routine is exited.

Table 1 shows an example of the results when the conventional power control and the power control of the present embodiment are used. In the example shown here, the AC power supply voltage is an effective value of 100 V, and the desired applied power is 400 W.

In the conventional power control, the power error is 11% at maximum.
On the other hand, in the power control of this embodiment, the maximum power error is 4.
It is suppressed to 25%, and the fluctuation of electric power is also small.

[0160]

[Table 1] <Fifth Embodiment> (FIG. 16) FIG. 16 shows a flowchart of the heating body temperature control program of the present embodiment. In this embodiment, the heating body power control circuit is the same as that of the fourth embodiment (FIG. 12).

The program shown in FIG. 16 is also programmed in the built-in ROM in the microcomputer 31 described above, and may be called by a main sequence program or the like at fixed time intervals or as needed to be executed. It has become.

First, in step 31 after entering the heating element control routine, the heating element resistance value setting unit 36 outputs 1N.
The resistance value of the heating element 21 in the room temperature state is detected by the signal input to 4.

Similarly, at step 32, the current temperature of the heating element 21 is detected by the signal input from the thermistor 24 to 1N1.

In step 33, it is determined whether or not the temperature of the heating element 21 detected in step 32 deviates from a predetermined range when the apparatus is operating normally, and it is normal. When it is determined that the condition is normal, the process proceeds to step 34, and when it is determined that the condition is not normal, the process proceeds to step 20.

Here, step 20 is a routine for error processing, which is an endless loop in which all outputs of all devices (copiers in this embodiment) are turned off and an error is displayed by using some display means. And prevents the main program from running.

At step 34, the zero point detection unit 32 outputs 1
The zero point of the AC power source is detected by the signal input to N2, and if the zero point is not detected, the process exits to the exit of this loop. When the zero point is detected, the process proceeds to step 35 and the heating body energization control is performed.

In step 35, every time the AC zero point is detected, a signal is output from the OUT1 terminal to the energization control section 33 in accordance with the order of wave number combinations previously determined in step 39 of this routine to energize the heating element 21. Alternatively, stop energization.

In step 36, it is judged whether or not the last control of the control unit previously determined in step 38 of this routine is finished. If it is in the middle of the control unit, the process exits to the exit of this routine and the last of the control unit is judged. If the control is completed, the process proceeds to step 37.

In step 37, the resistance value of the heating element 21 at room temperature detected in step 31 is corrected by the temperature of the heating element detected in step 32, and the process proceeds to step 38.

In step 38, a new control unit of wave number is determined based on the resistance value of the heating element whose temperature is corrected in step 37.

Here, when the control unit is determined, the control unit may be calculated by a resistance and a certain function, or may be stored as table data in the ROM. In addition, the upper limit value or the lower limit value or both are specified in the control unit,
The control unit may be determined within the range.

Next, in step 38, the combination of wave numbers is determined so that the desired amount of power can be obtained in the newly determined control unit.

Also in this case, the wave number may be obtained by calculation with a desired applied power amount and a certain function as in step 7, or may be stored as table data in the ROM. After the above processing is completed, this heating body control routine is exited.

As in the fourth and fifth embodiments, the heating means is provided with control means for controlling the number of half-waves of the AC power source applied to the heating body within a predetermined time. By including the detection means for detecting the resistance value information of the body and the control means for controlling the predetermined time according to the detection signal of the detection means, the accuracy of switching the applied power is increased, so that the desired power can be obtained. It is easy to obtain the image and the image formation can be stably performed.

Further, the accuracy of switching the amount of electric power required for heating and fixing is increased, and stable image formation is performed without wasting electric power, which contributes to power saving and energy saving of the copying machine.

C. The following sixth embodiment is an embodiment of a heating device having the structure described in claims 12 to 14 of the above claims or an image forming apparatus provided with the heating device as a fixing device.

The structure of the image forming apparatus shown in FIG. 1 and the structure of the fixing device shown in FIGS. 2 and 3 are the same in this sixth embodiment.

<Sixth Embodiment> (FIGS. 17 to 22) FIG. 17 is a block diagram of a heating body power control circuit of this embodiment, which is similar to the circuit of FIG.

In the present embodiment, the energization control of the heating body 21 is performed by controlling the predetermined number of blocks of the wave between the zero point and the next zero point with the minimum unit between the zero point of the AC power source 34 and the next zero point. It is energized as a block unit. The heating element 2 is controlled by controlling the number of energized waves between control block units.
Control the power applied to unit 1.

For example, a control block unit is 4 waves, a power source voltage of the AC power source is 100V, a frequency is constant, and a heating body resistance value is 10Ω.
When controlling W, the control block is controlled so that only three waves are energized.

An example thereof is shown in FIG. The shaded waves are the energized waves. The minimum power unit controlled by the wave number of the control block unit is determined, and in the example of the heating body of the present embodiment, it is possible to control in the unit of 250 W when the control block unit is 4 waves.

19 and 20 show a flow chart of the heating body temperature control program in this embodiment. This program is also a micro computer 31 as a control means.
The program flow shown in FIGS. 19 and 20 is programmed at a fixed time interval, or is called by a main sequence program or the like as necessary and executed. ing.

FIG. 19 shows a routine for controlling the heating element.

In step 1, 1N is output from the thermistor 24.
The current temperature of the heating element 21 is detected by the signal input to 1.

In step 2, it is determined whether the temperature of the heating element 1 detected in step 1 deviates from a predetermined range when the device is operating normally, and it is normal. When it is determined that the condition is normal, the process proceeds to step 3, and when it is determined that the condition is not normal, the process proceeds to step 20.

Here, step 20 is a routine for error processing, which is an endless loop in which all outputs of all devices (copiers in this embodiment) are turned off and an error is displayed with some display means. And prevents the main program from running.

[0187] In step 3, the zero detection unit 32 outputs 1N.
The zero point of the AC power supply is detected by the signal input to 2,
If the zero point is not detected, the process exits to the heating body control routine. When the zero point is detected, step 5
20. Then, the routine for calling the electric power application control to the heating element shown in FIG. 20 is executed.

In step 10 of FIG. 20, whether to energize for a half wave is determined according to the order of combination of wave numbers of control units. When energization for a half wave is not performed, the process branches to step 16, When energizing the waves, the process branches to step 11.

At step 11, the counter C is incremented by one each time an AC half-wave is output.

When C is 2 in step 12, the process branches to step 13 to set C to 0. When C is 1, step 13 is skipped. That is, the counter C takes a value of 0 or 1 before proceeding to step 14.

In step 14, a signal is output from the OUT1 terminal to the energization controller 33 to energize the heating element 21.

At step 16, it is judged whether or not the last control of the control unit is finished. If it is in the middle of the control unit, the process exits to this routine. If the last control of the control unit is finished, the process goes to step 17. Transition.

In step 17, a combination of wave numbers (contents of the control block) is set in the ROM so that a desired amount of power can be obtained in the control unit based on the temperature of the heating body 21 detected in step 1. Search from the pattern table.

FIG. 22 shows a ROM when the number of control blocks is 4.
The image of the energization output stored inside is shown.

At step 18, when the value of the counter C is 0, the process exits to this routine. When the value of C is not 0 (when the value of C is 1), step 19 is executed.

At step 19, the output pattern stored in the ROM is shifted to the left by half a wave. In other words, the image becomes an output when shifted by a half wave as shown in FIG.

After the above processing is completed, this heating body control routine is exited.

The energization pattern shown in FIG. 21 is obtained by applying the above-described loop operation to the conventional wave number control shown in FIG.

In the energization pattern of FIG. 18, the control units a to
When the energization control up to e is completed, the AC power consumption is increased by two half waves on the negative side. This deviation of the electric power generally increases as the control time increases.

However, in the example of FIG. 21, when the energization control for the control units a'-e 'is completed, the AC power consumption does not deviate to the plus side or the minus side, and the deviation of the power is the control time. Regardless of, at most it will be half-wave on the negative side.

As described above, the power supply to the heating element is
It has a control means for controlling the number of half-waves of an AC power source applied to the heating body within a predetermined time, and has a counting means for counting the number of main half-waves within a predetermined time. By having the means for changing the control pattern within the predetermined time, the electric power consumed by the energization control to the heating element does not deviate to the plus side or the minus side, which may adversely affect the external equipment or the parts inside the main body. It is possible to use the device stably without affecting.

D. The following seventh and eighth embodiments are embodiments of an image forming apparatus provided with a heating device or a heating device having the structure described in claims 16 to 19 of the above claims as a fixing device. .

The structure of the image forming apparatus shown in FIG. 1 and the structure of the fixing device shown in FIGS. 2 and 3 are the same in the seventh and eighth embodiments.

<Seventh Embodiment> (FIGS. 23 to 27) FIG. 23 shows a block diagram of a heating body energization control circuit in this embodiment.

Reference numeral 37 denotes a recording material leading edge detecting portion, and the recording material leading edge detection signal is supplied to the microcomputer 3 as a control means.
Enter 1. The other circuit configuration is the same as that of the circuit shown in FIG.

In the present embodiment, the energization control of the heating element 21 is performed by controlling a predetermined number of blocks of waves between the zero point and the next zero point with the minimum unit between the zero point and the next zero point of the AC power source. It is energized as a unit. The number of energized waves between control block units is controlled to control the electric power applied to the heating body 21.

For example, a control block unit is 10 waves, a power source voltage of the AC power source is 100 V, a frequency is constant, and a heating body resistance value is 10 Ω.
When controlling at 0 W, it is controlled so that only one wave is energized in the control block unit.

FIG. 26 shows an example thereof. The shaded waves in FIG. 26 are the energized waves. The minimum power unit controlled by the wave number of the control block unit is determined, and in the example of the heating body of the present embodiment, when the control block unit is 10 waves, it can be controlled in the unit of 100 W.

FIG. 24 shows a flowchart of the heating body temperature control program of this embodiment. This program is also programmed in the built-in ROM in the microcomputer 31 described above, and the flow of the program shown in FIG. 24 is executed at regular time intervals or when called by a main sequence program or the like as necessary. It is supposed to be done.

In step 1, the thermistor 24 outputs IN
The current temperature of the heating element 21 is detected by the signal input to 1.

[0211] In step 2, it is judged whether the temperature of the heating element 21 detected in step 1 deviates from a predetermined range when the apparatus is operating normally, and it is normal. If it is determined that the condition is normal, the process proceeds to step 3, and if it is determined that the condition is not normal, the process proceeds to step 70.

Here, step 70 is a routine for error processing, which is a permanent loop in which all the outputs of all the devices (copiers in this embodiment) are turned off and an error is displayed by using some display means. And prevents the main program from running.

At step 3, the signal input to IN3 from the recording material leading edge detecting portion 37 is detected, and if the leading edge is not detected, the routine branches to step 5, and if it is detected, the routine branches to step 4.

In step 4, the timer operation is started in which a predetermined time is set from the recording material leading edge detecting portion 37 until the recording material actually reaches the fixing device.

At step 5, the zero-point detection unit 32 outputs IN.
The zero point of the AC power supply is detected by the signal input to 2,
When the zero point is not detected, the process proceeds to step 9.

When the zero point is detected, the routine proceeds to step 6, where a signal is output from the OUT1 terminal to the energization controller 33 to energize the heating element 21 by controlling the wave number.

At step 7, it is judged whether or not the last control of the control unit is finished. If it is in the middle of the control unit, step 7 is skipped and the process goes to step 9, where the last control of the control unit is finished. If so, go to step 8.

In step 8, the combination of wave numbers (contents of the control block) is determined based on the temperature of the heating element 21 detected in step 1 so as to obtain a desired amount of power in the control unit. At this time, the desired amount of applied power,
The wave number may be obtained by calculation using a certain function, or may be stored as table data in the ROM.

In step 9, it is judged whether or not the count of the timer set in step 4 is finished. If the count of the timer is finished or the counter is not operating, step 10 is skipped and this heating body control loop is executed. Step 10 is executed after exiting the process and counting of the predetermined time set in step 4 is completed.

In step 10, the timer started in step 4 is stopped, and when the output pattern has the wave number shown in FIG. 27, the output pattern is changed to that shown in FIG. This operation is performed on the wave number output pattern as shown in the example of FIG.

The output pattern may be changed only in the control block at the leading edge of the recording material, or may be changed in any number of control blocks following it as shown in FIG. After performing the above operation, the heating body control loop is exited.

<Eighth Embodiment> (FIGS. 28 to 31) FIG. 28 is a block diagram of a heating body energization control circuit in this embodiment.

Reference numeral 38 is a control unit of the registration roller 8,
It is controlled by the microcomputer 31 as a control means. The other circuit configuration is the same as that of the circuit shown in FIG.

29 and 30 are flowcharts of the heating body temperature control program of this embodiment. This program is also programmed in the built-in ROM in the microcomputer 31 described above. It is designed to be executed.

FIG. 29 shows a routine for controlling the heating element.

At step 11, the thermistor 24 outputs I
The current temperature of the heating element 21 is detected by the signal input to N1.

In step 12, it is judged whether or not the temperature of the heating element 21 detected in step 1 deviates from a predetermined range when the apparatus is operating normally, and it is normal. When it is determined that the condition is normal, the process proceeds to step 13, and when it is determined that the condition is not normal, the process proceeds to step 70.

Here, step 70 is a routine for error processing, which is a permanent loop for turning off all the outputs of all devices (copiers in this embodiment) and displaying an error with some display means. And prevents the main program from running.

[0229] In step 13, the zero point detection unit 12 outputs I
The zero point of the AC power supply is detected by the signal input to N2, and if the zero point is not detected, the heating body control loop is exited. A signal is output to the control unit 13 to energize the heating element 1 by wave number control.

At step 15, it is judged whether or not the last control of the control unit is finished. If it is in the middle of the control unit, step 16 is skipped to exit this heating body control loop, and the last control of the control unit is finished. If so, step 1
Go to 6.

In step 16, the combination of wave numbers (contents of the control block) is determined based on the temperature of the heating element 21 detected in step 11 so that a desired amount of power can be obtained in the control unit.

At this time, the wave number may be obtained by calculation with a desired applied power amount and a certain function, or may be stored as table data in the ROM.

After performing the above operations, the heating body control loop is exited.

FIG. 30 is a flow chart showing the conveyance of the recording material and the other processing when the copy key is pressed.

After performing the pretreatment necessary for copying in step 21, the process proceeds to step 22, and the recording material P stored in the cassette S is controlled by the feeding roller 7 to start the conveyance of the recording material. To do.

At step 23, the registration of the recording material is aligned at the timing when the recording material reaches the registration roller 8 (registration alignment means correcting skew of the recording material).

After that, in step 24, ta 'shown in FIG. 31 may be stored in advance in the ROM, or may be calculated from the control wave number block or other factors.

At step 25, the counting of the timer is started, and at step 26, the registration roller 8 is stopped and waits until the counting of the timer is completed.

When the counting is completed, the process proceeds to step 27 and the operation of the registration rollers 8 is started to convey the recording material.

At this point, the plunge point A at which the recording material plunges into the fixing device is shifted to A ', as shown in FIG.
By this operation, the electric power of the wave number is aligned with the leading end of the recording material.

Next, after performing the copying operation in step 28,
In step 29, post-processing of copying is performed, and this loop is ended.

As described above, the power supply to the heating element is
The detecting means has a control means for controlling the number of half-waves of the AC power source applied to the heating body within a predetermined time, and a detecting means for detecting the timing at which the tip of the recording material plunges into the heating body. By providing a means for changing the control pattern within the predetermined time in accordance with the detection signal, the stable image formation can be performed over the entire area of the recording material without causing fixing failure even at the leading end of the recording material.

[0243]

As described above, according to the present invention, there is provided a film heating type heating device or an image forming apparatus provided with the heating device as a fixing device. In the image fixing device, it is possible to prevent the occurrence of uneven heating processing of the material to be heated, and to prevent the occurrence of defective fixing at the leading end of the recording material in the image fixing device. The accuracy of switching the applied power is increased, the desired power is easily obtained, stable heating of the material to be heated can be performed, and in the image fixing device, stable and good heat fixing without uneven fixing can be performed. Power consumption that is biased to the positive or negative side of the alternating current applied to the heating element is eliminated, and it is possible to use the equipment stably without adversely affecting external equipment and internal parts of the main body. Prevents uneven heating of the material to be heated due to sections where the heating element is not energized, prevents the fixing failure of the leading edge of the recording material in the image fixing device, and provides stable heat fixing processing over the entire area of the recording material. The above-mentioned first to fourth objects are well achieved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an example of an image forming apparatus.

FIG. 2 is a schematic configuration diagram of a fixing device.

FIG. 3 is a plan view of the heating element (heater), with an intermediate part omitted, as viewed from the side of the energization heating element layer formation surface.

4A and 4B are schematic configuration diagrams of another example of a fixing device.

FIG. 5 is a block diagram of a heating body power control circuit of the first embodiment device.

6A and 6B are explanatory views of energization control.

FIG. 7: Flow chart of energization control

FIG. 8: Sub-flow chart of energization control

FIG. 9 is a sub-flowchart of energization control of the second embodiment device.

FIG. 10 is a flow chart of energization control of the third embodiment device.

FIG. 11 is a sub-flowchart of energization control of the third embodiment device.

FIG. 12 is a block diagram of a heating body power control circuit of a fourth embodiment device.

FIG. 13 is an explanatory diagram of a control block of wave number control.

FIG. 14 is a flowchart of a heating body control program.

FIG. 15 is a flowchart of a heating body control program.

FIG. 16 is a flow chart of a heating body control program of the fifth embodiment device.

FIG. 17 is a block diagram of a heating body power control circuit of a sixth embodiment device.

FIG. 18 is an explanatory diagram of a control block of conventional wave number control.

FIG. 19 is a flowchart of a heating body control program

FIG. 20 is a flowchart of a heating body control program.

FIG. 21 is a control block explanatory diagram of wave number control in the sixth embodiment.

FIG. 22 is an image diagram of energization output for wave number control in the sixth embodiment device.

FIG. 23 is a block diagram of a heating body power control circuit of the seventh embodiment device.

FIG. 24 is a flowchart of heating body control.

FIG. 25 is an explanatory diagram for heating the leading edge of the recording material.

FIG. 26: Image diagram of energization output for wave number control

FIG. 27 is an explanatory view of heating of the leading end of the recording material by conventional wave number control.

FIG. 28 is a block diagram of a heating body power control circuit of an eighth embodiment device.

FIG. 29 is a flowchart of heating body control.

FIG. 30: Flow chart of heating element control

FIG. 31 is an explanatory diagram of heating of the leading end of the recording material.

[Explanation of symbols]

 11 General Reference Code of Fixing Device (Heating Device) 25 Heat Resistant Film (Fixing Film) 21 Heater (Heater) 22 Heater Substrate 23 Electric Heat Generation Layer (Heating Part) 28 Pressure Roller P Recording Material (Transfer Material Sheet) 31 Micro Computer (control unit) 32 Zero point detection unit 33 Energization control device 34 AC power supply 35 Sheet sensor 36 Heater resistance value setting unit 37 Recording material tip detection unit 38 Registration roller control unit

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location G05D 23/24 G 9132-3H

Claims (19)

[Claims] 1. A heating body, which generates heat when energized, and a heat-resistant film which is conveyed in contact with the heating body. In the heating device of the film heating system, which transfers the heat energy of the heating body to the material to be heated through the film by transporting it through the heating body position, the half-wave of the AC power applied to the heating body within a predetermined time Control means for controlling the number of the heating elements, detection means for detecting that the material to be heated reaches the heating device, and means for controlling the electric power applied to the heating body according to the detection information of the detection means. A heating device characterized by. 2. The applied power 1 before and after the material to be heated reaches the heating device and the applied power 2 at other times according to the detection information of the detection means: applied power 1> applied power 2 The heating device according to claim 1, further comprising a control unit that controls so that the heating device becomes 3. The heating device according to claim 1, further comprising control means for controlling the predetermined time period according to detection information from the detection means. 4. The heating device according to claim 1, wherein the number of half-waves of an AC power source applied to the heating element within the predetermined time is controlled according to the detection information of the detection means. 5. The heating device according to claim 1, wherein the predetermined time is a positive multiple of one half of an AC power supply cycle applied to the heating body. 6. The heating device according to claim 1, wherein the recording material image is a recording material as a material to be heated on which a heat-fixable developing material image is formed and supported. An image forming apparatus provided as a fixing device for heating and fixing. 7. A heating body that generates heat when energized and a heat-resistant film that is conveyed in contact with the heating body, wherein a material to be heated is adhered to the side surface of the film opposite to the heating body side, and the film is put together with the film. In the heating device of the film heating system, which transfers the heat energy of the heating body to the material to be heated through the film by transporting it through the heating body position, the half-wave of the AC power applied to the heating body within a predetermined time A heating device comprising: a control unit that controls the number of the heating elements; a detection unit that detects resistance value information of the heating element; and a unit that changes the predetermined time period according to a detection signal of the detection unit. 8. The heating device according to claim 7, wherein the resistance value information is resistance value information of the heating body at room temperature. 9. The heating device according to claim 7, wherein the resistance value information is resistance value information that changes with a temperature change of the heating body. 10. The heating device according to claim 7, wherein the predetermined time is a positive multiple of one half of an AC power supply cycle applied to the heating body. 11. The heating device according to claim 7, wherein the recording material image of a recording material as a material to be heated on which a heating-fixable developing material image is formed and carried is used as a recording material. An image forming apparatus provided as a fixing device for heating and fixing. 12. A heating body which is heated by energization and a heat resistant film which is conveyed in contact with the heating body, and a material to be heated is adhered to a side surface of the film opposite to the heating body side and the film is put together with the film. In the heating device of the film heating system, which transfers the heat energy of the heating body to the material to be heated through the film by transporting it through the heating body position, the half-wave of the AC power applied to the heating body within a predetermined time Heating means characterized by having a control means for controlling the number of half-waves, a counting means for counting the number of half-waves output within the predetermined time, and a means for changing the control pattern within the predetermined time according to the count value. apparatus. 13. The heating device according to claim 12, wherein the predetermined time is a positive multiple of one half of an AC power supply cycle applied to the heating body. 14. The heating device according to claim 12 or 13, wherein the carried developing material image of a recording material as a material to be heated on which a heat fixing property developing material image is formed and carried is heated and fixed to the recording material. An image forming apparatus provided as a fixing device. 15. A heating body that generates heat when energized and a heat-resistant film that is conveyed in contact with the heating body. In the heating device of the film heating system, which transfers the heat energy of the heating body to the material to be heated through the film by transporting it through the heating body position, the half-wave of the AC power applied to the heating body within a predetermined time A heating device characterized by having a control means for controlling the number of the heating elements, and a means for controlling the heating material so as to match the energized portion in the control pattern within the predetermined time at a timing when the material to be heated rushes into . 16. A control means for controlling the heating member to match the current-carrying portion in the control pattern within the predetermined time at the timing when the tip of the heating target member rushes into the heating member. 16. The control device according to claim 15, further comprising a detection unit that detects a timing at which the tip portion rushes, and that changes a control pattern within the predetermined time period according to a detection signal from the detection unit. Heating device. 17. A control means for controlling the heating material to move to the heating body at a timing when the tip of the heating material enters the heating body so as to coincide with an energized portion in the control pattern within the predetermined time. 16. The control for delaying the inrush timing according to a pattern for controlling the inrush timing.
The heating device according to. 18. The heating device according to claim 15, wherein the predetermined time is a positive multiple of one half of an AC power supply cycle applied to the heating body. 19. The heating device according to claim 15, wherein the recording material image of the recording material as a material to be heated, on which the image material image of heat fixing property is formed and supported, is used as the recording material. An image forming apparatus provided as a fixing device for heating and fixing.