JP2001110551A - Heating apparatus, heating fixing apparatus, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heating apparatus to suppress excess temperature rise at a non-paper transfer part, and not to have temperature difference between the paper transfer part and the non-paper transfer part of a pressure roller which is opposing to the heater. SOLUTION: The heating apparatus has a temperature uniformalizing body arranged neighboring the heater, and the driving mechanism to change the position of the temperature uniformarizing body, to touch to or not to touch the heater.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating device for applying thermal energy to a recording material as a material to be processed, and more particularly, to a heating member (heating body) fixedly supported by applying a heat-resistant heat film to a pressing member. By forming a pressure contact nip by pressing in, the recording material is introduced between the heat-resistant heat film and the pressure member of the pressure-contact nip, and the pressure-contact nip is moved together with the heat-resistant heat film, A heating device for applying heat energy of a heating member to a recording material through a heat-resistant heat film to modify surface properties such as gloss of the recording material, and applying the heating device as a heat source to transfer material, photosensitive material, and the like. A heat fixing device for thermally fixing an unfixed toner image formed on a recording material such as paper or electrostatic recording paper onto the recording material; a copying machine using an electrophotographic method or an electrostatic recording method to which the heat fixing device is applied; Images from printers and facsimile machines It relates forming apparatus.

[0002]

2. Description of the Related Art Conventionally, as the above-mentioned heating device, a heat roller type device which sandwiches and conveys a recording material between a heating roller and a pressure roller has been widely used. Has a large heat capacity, so that the time required to heat the heating roller to a predetermined temperature (so-called warm-up time) is long.

[0003] Therefore, heating by a film heating method in which a warm-up time is shortened by using a heating body having a low heat capacity and a thin heat-resistant heat film (hereinafter abbreviated as a heating film) sliding on the heating body. An apparatus has been proposed (JP-A-63-313182, JP-A-2-157).
No. 878).

FIG. 5 shows a heating and fixing device using a heating device based on the film heating method as a heat source. Reference numeral 2 denotes a heating body which is supported by exposing a heat radiation surface to a support 6; An endless heat film 3 rotatably stretched by the guide roller 15 is a pressure roller for pressing the heat film 14 against the heating body 2 to form a pressure contact nip portion 16. The heat film 14 is driven to rotate in the direction of the arrow by the rotation of the pressure roller 3 which is in pressure contact, or is rotated by applying power from a drive source (not shown) to one of the guide rollers 15.

FIG. 6 is a plan view showing the structure of the heating element 2 in which a middle part on the front side is omitted and a part is cut away.
FIG. 3 is a plan model view of the heating element 2 in which an intermediate portion on the back surface side is omitted. The heating element 2 is a planar substrate 2 made of ceramics such as alumina having electrical insulation, high heat resistance, low heat capacity, and good thermal conductivity, having a longitudinal direction perpendicular to the conveying direction of the recording material P.
a and Pd / Ag formed on the front surface side (film sliding surface side) of this substrate through pattern printing and firing along the length.
Linear or band-shaped current-generating heating resistor layer (heating element) 2b
And has a low heat capacity as a whole.

[0006] Reference numerals 2e and 2g denote first and second electrode patterns for power supply, which are provided side by side on one longitudinal end of the front surface of the substrate 2a. The first power supply electrode pattern 2e is electrically connected to one end of the energized heating resistor layer 2b. Further, the second power supply electrode pattern 2g is electrically connected to the other end of the energized heating resistor layer 2b via the conductive path pattern 2f.
The surface of the substrate on which the heat generating resistor layer 2b and the conductive path pattern 2f are formed is covered with a thin electrically insulating and heat-resistant surface protective layer 2c such as glass or fluorine resin.

Reference numerals 2h and 2n denote first and second electrode patterns for temperature control, which are provided side by side on the other end surface side of the front surface of the substrate 2a. Reference numeral 2d denotes a thermistor as a temperature detecting means for heat fixing, which is disposed at an appropriate position on the back side of the substrate 2a. 2j and 2k are two thermistor lead conductive path patterns provided on the back surface side of the substrate 2a. One end of the conductive path pattern 2j on the opposite side to the thermistor 2d side is electrically connected to the first temperature control electrode pattern 2h on the substrate surface side through the conductive through hole 2i. The other end of the other conductive path pattern 2k opposite to the thermistor 2d is electrically connected to the second temperature control electrode pattern 2n on the substrate surface via a conductive through hole 2m. Electrode patterns 2e, 2g, 2h, 2n, conductive path patterns 2f, 2j,
2k and the conductive through holes 2i and 2m are formed by pattern printing and firing of a conductive material such as Ag @ 1st.

The power supply connector 4 is fitted to one end of the heater 2 so that the first and second electrode patterns 2e and 2g for power supply on the heater 2 side have contact points 4a of the connector 4 respectively. , 4b are in contact with each other, and the commercial power source E → the first power supply electrode pattern 2e → the energizing heating resistor layer 2b → the conductive path pattern 2f → the second power supply pattern 2g → the switching element 7 such as a triac → the energization of the commercial power source E Electric power is supplied to the current-carrying heating element layer 2b of the heating element 2 by the circuit, and the heating element 2 is heated.

Further, the temperature detecting connector 5 is fitted to the other end of the heating element 2 so that the first temperature control on the heating element 2 side can be performed.
And connectors 5 of second electrode patterns 2h and 2n, respectively.
Contacts 5a and 5b on the heating side 2 (substrate side 2).
a) A thermistor 2d as a thermal fixing temperature detecting means on the back side is connected to an A / D converter 8 of a control system.

That is, A / D converter 8 → first temperature control electrode pattern 2h → conductive through hose 2i → conductive path pattern 2j → thermistor 2d → conductive path pattern 2k → conductive through hose 2m → second temperature control second electrode pattern 2n → A / D The circuit of the D converter 8 is configured.

As described above, the thermistor 2d as the thermal fixing temperature detecting means on the back side of the heating element 2 and the A / D converter 8 of the control system are connected, and the extracted thermistor voltage is used for the A / D converter. 8, the heating element temperature detection information by the thermistor 2 d is taken into the CPU control unit 9 as digital data. This CPU control unit 9
Is a switching element 7 based on the input digital data.
In step (2), the power supply to the heating element layer 2b of the heating element 2 is controlled to control the temperature so as to maintain the apparatus temperature at a predetermined optimum temperature for thermal fixing for thermally fixing the toner image.

The fixing operation in the heat fixing device using the heating device as a heat source is as follows. The recording material P is transferred to the press-contact nip portion 16 formed by pressing the heating member 2 and the pressing member 3 with the heat film 14 interposed therebetween. By passing the recording material P together with the unfixed toner image t, the visible image gripping body surface of the recording material P is heated by the heating body 2 via the thermal film 14 to soften and melt the toner. Thus, fixing is performed on the recording material P.

[0013]

In the heat fixing apparatus using the above-described heating device as a heat source, the temperature of a heat film or heater as a heating member is detected by a temperature detecting means such as a thermistor. By controlling the power supply to the energized heating resistor layer based on the temperature, the temperature is controlled to a predetermined temperature.

In this case, a thermistor as a temperature detecting means is disposed on a heat film portion or a heater portion which becomes a paper passing portion for recording materials of various sizes, large and small, which can be used for the heat fixing device, and the heater portion is provided. Is detected and fed back to the energization control circuit. That is, energization to the energized heating resistor layer is controlled based on the detected temperature of the paper passing portion so that the temperature of the paper passing portion is maintained at a predetermined fixed fixing temperature.

However, in an apparatus having such a temperature control configuration, a small size, for example, B, which is smaller than the maximum size that can be passed through the apparatus, for example, B4 or A3 size recording material,
If a small-size recording material such as an envelope or postcard is continuously passed through the device, the non-sheet-passing portion of the energized heating resistor layer (the entire effective heat generation area of the energized heating resistor layer and the small-sized The difference between the size and the width of the recording material is the same as that of the portion corresponding to the sheet passing portion, and heat is generated with a predetermined amount of heat per unit length, although heat energy is not consumed for heating the recording material. A so-called non-sheet-passing portion temperature increasing phenomenon occurs in which heat is stored and the temperature rises higher than the sheet-passing portion.

Due to the rise in the temperature of the non-sheet passing portion, the pressure roller as a pressing member which is in pressure contact with the heating element also has a temperature difference between the portion corresponding to the sheet passing portion and the portion corresponding to the non-sheet passing portion. Occurs. In particular, in the case of a so-called one-sided reference transport device in which the recording material is fed toward the base line on either the left end side or the right end side in the longitudinal direction of the heating element, the pressing roller has a sheet passing corresponding portion and a non-sheet passing portion. In some cases, the temperature difference may be 100 ° C. or more.

As a solution to the rise in the temperature of the non-sheet passing portion, a method of providing a plurality of heat generating patterns of a heating element and selectively energizing only a sheet passing area in accordance with the size of a recording material to be passed (Japanese Patent Laid-Open No. 06-003983). Japanese Patent Application Laid-Open No. H06-19345, etc.) A method of providing a cooling fan that blows air only to a non-sheet passing portion according to the size of a recording material (Japanese Patent Application Laid-Open No. H06-19345). A method of opening a cooling window near a non-sheet passing portion in accordance with the size of a recording material and cooling only the non-sheet passing portion (JP-A-09-009)
No. 44025).

However, in the above-described method, the control of energization to the heating element becomes complicated, and as a disadvantage, flicker occurs at the time of energization ON / OFF.

In the above-mentioned method, it is difficult to apply cooling air only to the non-sheet passing portion even if a partition or a duct is provided, so that the sheet passing portion is also cooled. Thus, there is a problem that the temperature inside the heat fixing device rises.

Further, a method of providing a cooling mechanism at the end of the rotating shaft of the pressure roller (JP-A-07-253731).
In this case, it is difficult to cool only the non-paper passing area accurately,
There was a problem that the paper passing portion was also cooled.

In addition, a method in which a heat equalizing roller or a heat equalizing plate is provided on the pressing roller to keep the temperature of the heat roller in the rotation axis direction constant (see JP-A-09-034290 and JP-A-06-25-25).
No. 0540), a method of installing a heat pipe in the vicinity of a heating element, and a method of using a material having good heat conductivity as a support for holding the heating element (both are disclosed in Japanese Patent Application Laid-Open No. 06-019345). Because the heat pipe, heat equalizing roller and heat equalizing plate were installed in the temperature rising area until the heat fixing device could fix, that is, in the temperature rising area,
Since the heat capacity of the portion to which heat is transmitted is increased, and the heat conductivity of the support is good, there are problems that the portion to which heat is transmitted at the time of temperature rise is widened, and it takes time for the temperature to rise.

There is also a method of installing a cooling mechanism in contact with the thermal film or a cooling mechanism in the vicinity of the thermal film (both are disclosed in JP-A-6-250540). Since the heat of the fixing device is taken away, there has been a problem that the thermal efficiency of the entire fixing device is reduced and power consumption is increased.

Further, the soaking roller in contact with the pressing roller, and the contact pressure of the soaking roller with the pressing roller,
There is also a method in which a mechanism that varies according to the temperature of the pressure roller or the heating element or the size of the recording material is provided. In this method, in order to adjust the temperature of the non-paper passing area of the heat film or the heating element, the heat of the non-paper passing area is transferred to the pressure roller and the heat film via the pressing roller and the soaking roller. In the interval between sheets (a state in which there is no paper in the press-contact nip portion during continuous sheet feeding), the heat is transmitted from the pressure roller to the heat-passing area of the heat film and the heating element. Therefore, when the sheet interval is reduced in order to increase the sheet passing speed, the effect of reducing the temperature difference between the sheet passing portion and the non-sheet passing portion of the heating element and the thermal film may be reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems. The present invention makes the temperature distribution in the rotation axis direction of the heating element and the thermal film gentle, thereby preventing the temperature rise in the non-sheet passing portion. It is an object of the present invention to obtain a heating device capable of shortening a rise time.

It is another object of the present invention to provide a heat fixing device capable of performing efficient heat fixing by using the heating device as a heat source and an image forming device capable of forming a high quality image by applying the heat fixing device. Aim.

[0026]

According to the present invention, there is provided a heating apparatus having the following constitution and an image forming apparatus to which the heating apparatus is applied.

(1) A support for supporting the heating element, an endless movable heat-resistant thermal film stretched in contact with the heating element and the support, and the heat-resistant thermal film A pressure member for pressing to form a pressure contact nip portion, wherein the heat treatment device sandwiches and transports the material to be processed in the pressure contact nip portion and applies the thermal energy of the heating body to the material to be processed, A heating apparatus comprising: a heat equalizer provided near the heating element; and a drive mechanism for changing a position of the heat equalizer so that the heat equalizer contacts or separates from the heating element. .

(2) The heat equalizer is made of a material having a good thermal conductivity and a small heat capacity. (1)
A heating device as described.

(3) The heating device according to (2), wherein the material having good thermal conductivity and small heat capacity is aluminum.

(4) The heating device according to (1), wherein the soaking body is brought into contact with the heating body in accordance with the size of the material to be processed.

(5) The heating apparatus according to (1), wherein the soaking body is brought into contact with the heating body after the heating body reaches a predetermined temperature.

(6) The heating apparatus according to (1), wherein the heat equalizing body is arranged at a position away from the heating body until the heating body reaches a predetermined temperature.

(7) A heating fixing device comprising the heating device according to any one of (1) to (6) as a heat source.

(8) An image forming apparatus comprising the heat fixing device according to (7).

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of the present invention will be described below in detail with reference to the drawings. FIGS. 1 and 2 show the configuration of a heat fixing device using the heating device according to the first embodiment as a heat source. FIG. 1 is a cross-sectional view of the pressure roller as viewed from the rotation axis direction, and FIG. 2 is an enlarged view of the vicinity of the heating body in FIG.

In FIG. 2, a heating element 1 is a heat source for heating the heating element 2. A linear heating element such as Pd / Ag formed on the surface of the heating element 2 along a longitudinal direction by pattern printing and firing. Alternatively, it is a thin strip-shaped current-generating resistor layer. The heating element 1 has a sufficient length to warm the entire heating element 2. The heating element 2 is supported by the support 6 with the heat radiation surface exposed. A temperature detector 17 such as a thermistor is pressed against one or more locations on the surface of the heating element 2, and a temperature control mechanism (not shown) generates a heating element based on the temperature measured by the temperature detector 17. By controlling ON / OFF of the power supply path for 1, the surface temperature of the movable endless heat film 14 is maintained in a predetermined temperature range.

The heat film 14 has a small heat capacity,
To speed up the temperature rise, its thickness should be 10
μm or less, PTFE, PFA, FEP, etc. coated on a single layer of PTFE, PFA, FEP or polyimide, polyamide imide, PEEK, PES, PPS with heat resistance, release property, strength, durability, etc. The composite layer film is used.

Referring to FIG. 1, the thermal film 14 is
And a plurality of guide rollers 15 so as to be movable, but are pressed against the pressure roller 3 having substantially the same length as the thermal film 14 by a pressing mechanism (not shown). The pressure roller 3 is made of a member 3a having good heat conductivity such as aluminum, and its surface is coated with a soft material 3b such as rubber or fluorine resin.

An oil application roller is pressed against the heat film 14 by a pressure mechanism (not shown), and the oil application roller applies oil supplied from an oil supply mechanism (not shown) to the heat film 14. This is because the toner is easily peeled off from the thermal film 14.

The paper feed guide 5 transports the recording material P on which the unfixed toner image t is transported by a transport roller (not shown) not shown to the heat film 14 and the pressure roller 3.
To the press-contact nip 16. The press nip 16
Then, the recording material P is supplied with thermal energy from the heating body 2 via the thermal film 14, and is simultaneously pressed by the thermal film 14 and the pressure roller 3, so that the unfixed toner image t is thermally fixed to the recording material P. You. The heat-fixed recording material P is peeled off from the thermal film 14 by the peeling claw 8, and is guided to a discharge roller (not shown) by the discharge guide 7.

The heat equalizer 10 is installed to face the heater 2 and is pressed against the heater 2 according to the size of the recording material P by a solenoid 11 as a driving mechanism. The heat equalizer 10 is made of a member having good heat conductivity such as aluminum and having a small heat capacity.

FIG. 3 is a perspective view of a main part of the structure of the first embodiment, and FIG. 3 shows a paper feed guide 5 and a paper discharge guide 7.
Although not particularly shown, the peeling claw 8 and the like are provided in the same manner as in FIG. The heat film 14 and the pressure roller 3 receive power via the gear train 12 and rotate, and the power is supplied from the motor 13. The number of teeth of the gear train 12 is adjusted so that the speed of the heat film 14 and the speed of the pressure roller 3 on the surface of the heat equalizer 10 are the same.

The operation of the solenoid 11 is controlled by a solenoid control mechanism (not shown). When the temperature rises, the solenoid 11 is turned off and the heat equalizer 10
Is separated from the surface of the heating element 2 by the elastic force of an elastic member (not shown).

For example, if the maximum size of the recording material P usable in the fixing device is A3, when the recording material P having the same width as A3 such as a landscape A4 paper is passed, the solenoid 11 is turned off, and The heating element 10 is separated from the surface of the heating element 2. When a recording material P having a width of A3 or less such as A4 paper or B5 paper is passed, the solenoid 11 is turned on, and the heat equalizer 10 is pressed against the heat generator 2 against the elastic force of the elastic member. Let it. As a result, the temperature of the heating element 2 is adjusted to a substantially uniform temperature over the entire length.

(Second Embodiment) Hereinafter, a second embodiment of the present invention will be described. Although not illustrated in the second embodiment, a thermometer 17 such as a thermistor is pressed into contact with one or more of the center of the paper passing portion on the surface of the heating element 2 and one or more ends of the heating element. Since the other configuration is the same as that of the first embodiment, the same portions are denoted by the same reference numerals and the description thereof will not be repeated.

Next, a method of operating the solenoid in the heat fixing device according to the second embodiment will be described with reference to FIG. The operation of the solenoid 11 is controlled by a solenoid control mechanism (not shown). When the temperature rises, the solenoid 11 is turned off and the heat equalizing body 10 is separated from the surface of the heating body 2. Is turned on / off as follows.

For example, if (temperature near the end of the heating element 2 measured by the temperature detector 17) − (temperature near the center of the heating element 2 measured by the temperature detector 17) <(predetermined temperature difference), When the solenoid 11 is turned off, the heat equalizer 10 is separated from the surface of the heat generator 2 by the elastic restoring force.

If (temperature near the end of the heating element 2 measured by the temperature sensor 17) − (temperature near the center of the heating element 2 measured by the temperature sensor 17) ≧ (predetermined temperature difference), The solenoid 11 is turned on, and the heat equalizer 10 is pressed against the heat generator 2 against the elastic restoring force to achieve uniform temperature control. Except for the operation of the solenoid 11, the operation is the same as that of the first embodiment, and the description is omitted.

(Third Embodiment) FIG. 4 is a block diagram of an image forming apparatus to which the heat fixing device of the first or second embodiment using the heating device according to the present invention as a heat source is applied. In FIG. 4, reference numeral 51 denotes a photosensitive drum on which a photosensitive material such as OPC, amorphous Se, or amorphous Si is formed on a cylindrical substrate such as aluminum or nickel. The photosensitive drum 51 is driven to rotate in the direction of the arrow,
First, the surface is uniformly charged by a charging roller 52 as a charging device.

Next, the charged surface of the photosensitive drum 51 is irradiated with a laser beam 53 that has been turned on / off in accordance with image information.
Is performed to form an electrostatic latent image. This electrostatic latent image is developed and visualized by the developing device 54. As a development method, a jumping development method, a two-component development method, or the like is used, and a combination of image exposure and reversal development is often used.

The visualized unfixed toner image is transferred from the photosensitive drum 51 onto the recording material P conveyed at a predetermined timing by a transfer roller 55 as a transfer device. Here, the sensor 58 detects the leading end of the recording material and adjusts the timing so that the image forming position of the unfixed toner image on the photosensitive drum 51 and the writing start position of the leading end of the recording material match. The recording material P conveyed at a predetermined timing is nipped and conveyed by the photosensitive drum 51 and the transfer roller 55 with a constant pressing force. The recording material P to which the unfixed toner image has been transferred is conveyed to the heat fixing device 56 according to the present invention, and passes through the heat fixing device 56 so that the unfixed toner image is fixed on the recording material as a permanent image. You. On the other hand, the transfer residual toner remaining on the photosensitive drum 51 is removed from the surface of the photosensitive drum 51 by the cleaning device 57.

It should be noted that the present invention is not limited to these embodiments, and each component may be replaced with an alternative as long as the object of the present invention is achieved.

[0053]

As described above, according to the present invention, a support for supporting a heating element, a movable endless heat film stretched in contact with the heating element and the support,
A pressurizing member that presses the thermal film to the heating element so as to form a press-contact nip portion, and pinches and conveys the recording material in the press-contact nip portion to apply heat energy of the heating element to the recording material. In the heating device to be provided, the heat equalizing body installed in the vicinity of the heating body is configured to be in contact with or separated from the heating body, and has a high thermal efficiency, a fast temperature rise, and a press-contact nip portion. The problem that the temperature of the non-paper passing area becomes higher than the temperature of the paper passing area can be solved. As a result, it is possible to reliably prevent the occurrence of fixing unevenness due to an increase in the temperature of the non-sheet passing portion, the occurrence of heat loss of the heat film, the heater, the pressure roller, and other components, the reduction in durability, and the occurrence of twisting of the heat film. There is an effect that a heating device can be provided.

According to the present invention, since this heating device is provided as a heat source, it is possible to provide a heat fixing device capable of performing efficient heat fixing. Further, there is an effect that an image forming apparatus capable of forming a high-quality image free from toner contamination by applying this heat fixing device can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a main part of a first embodiment of a heat fixing device to which a heating device according to the present invention is applied.

FIG. 2 is a sectional view showing details in the vicinity of a heating body in FIG. 1;

FIG. 3 is a perspective view showing details of a drive mechanism of the heat equalizer in FIG. 1;

4 is a configuration diagram of an image forming apparatus to which the heat fixing device of FIG. 1 is applied.

FIG. 5 is a cross-sectional view illustrating a main part of a heat fixing device of a thermal film type according to the related art.

FIG. 6 is a plan view showing an example of a heating element in which a middle part on the surface side is omitted and a part is cut away.

FIG. 7 is a plan model view in which an intermediate portion on the back surface side of the heating element is omitted.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating element 2 Heating element 3 Pressure roller 4 Recording material (material to be processed) 6 Support body 10 Heat equalizer 11 Solenoid 12 Gear train 13 Motor 14 Heat film 15 Heat film guide roller 16 Pressure nip part 17 Temperature detector 51 Photosensitive drum 52 charging roller 53 laser beam 54 developing device 55 transfer roller

Claims (8)

[Claims] 1. A support for supporting a heating element, an endless and movable heat-resistant heat film stretched so as to be in contact with the heating element and the support, and the heat-resistant heat film is attached to the heating element. A pressurizing member for press-contacting so as to form a press-contact nip portion, wherein the press-contacting nip portion sandwiches and conveys the material to be processed and imparts thermal energy of the heating body to the material to be processed; A heating apparatus, comprising: a heat equalizer provided near a heating element; and a drive mechanism for changing a position of the heat equalizer such that the heat equalizer contacts or separates from the heating element. 2. The heating apparatus according to claim 1, wherein the heat equalizer is made of a material having a good thermal conductivity and a small heat capacity. 3. The material having a good thermal conductivity and a small heat capacity is aluminum.
A heating device as described. 4. The heating element according to claim 1, wherein the heating element is brought into contact with the heating element in accordance with the size of the material to be processed.
A heating device as described. 5. The heating device according to claim 1, wherein the heat equalizer is brought into contact with the heater after the heater reaches a predetermined temperature. 6. The heating apparatus according to claim 1, wherein the heat equalizing body is arranged at a position away from the heating body until the heating body reaches a predetermined temperature. 7. A heat fixing device comprising the heating device according to claim 1 as a heat source. 8. An image forming apparatus comprising the heat fixing device according to claim 7.