JPS62267788A - Fixing device for electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To melt toner under excellent conditions, by providing a heat pipe which presses a toner image between a position, at which a supporting body contacts a heating member, and another position, at which the supporting body is removed from the member. CONSTITUTION:Copying paper 22 is held between a heating roller 1 and heat pipe 16. An internal heating element 5, such as halogen lamp, etc., is provided on the inside of the hollow section of the heating roller 1 and the roller 1 is provided with an elastic layer 3 made of an elastic material, such as silicon rubber, etc., having thickness of 2-3mm at its surface on a metallic core 2 made of Al, etc. By detecting the heating temperature of the heating element 5 with a temperature sensor 23 and inputting the detected temperature to the controller of this copying machine, the surface temperature of the heating roller 1 is maintained at a fixed value. Moreover, the heat pipe 16 is made longer than the heating roller 1 and its one side section is protruded in the lateral direction from the heating roller 1. Therefore, the section of the heat pipe 16 opposing to the heating roller 1 absorbs heat from the roller 1 and the section protruded from the roller 1 radiates the heat. When air is blown to the protruding section of the heat pipe 16 from a fan, etc., its cooling effect is improved.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a fixing device configured to heat a support such as paper onto which a toner image has been transferred, from the back side of the support. In particular, the present invention relates to a fixing device configured to uniformly heat the support by configuring the support to be brought into close contact with a heating member.

(Prior art) The toner image transferred from the photoreceptor to the paper is fixed on the paper by heat, solvent, pressure, etc. when passing through a fixing device, which causes the toners to stick to each other and the toner to the paper. It is becoming more and more popular.

In the fixing process, copy speed, power consumption,
The optimum fixing method is selected from among various fixing methods by considering the capacity, maintainability, performance maintenance, etc. of the copying machine.

Among these, the thermal roller method applies thermal energy to the toner and paper through thermal conduction, and by passing the copy paper carrying the toner image between a pair of rollers, the thermal energy is transferred directly from the surface of the fixing roller. Fixing is performed by transferring heat and being subjected to pressure from a pressure roller.

The fixing roller is made of a material with excellent heat resistance, releasability, and mechanical strength, while the pressure roller has a surface layer with appropriate elasticity and forms a fixing nip. It is necessary to use a surface layer having the same function as the fixing roller. This type of fixing device has advantages such as high thermal efficiency of 60 to 80%, adaptability to high-speed copying machines, and high safety, and is now widely used in practice. In the case of fixing using the Radiant 6 type, thermal energy is applied to the toner and paper by radiant heat transfer for fixing, and an infrared lamp, a xenon flash lamp, etc. are used as the heat source. In this method, the fixing performance differs depending on the image density, and even if the toner particles are fixed in high-density areas, in low-density areas, the toner particles are often isolated and cannot absorb enough heat. This may result in insufficient fixation.

However, the above-described type of fixing device has the advantages of a simple structure, miniaturization, low price, and short warm-up time.

In the case of a xenon flash lamp, the fixing performance is improved compared to the infrared lamp method, but the disadvantages are that the power source is larger and more expensive.

Furthermore, in the pressure fixing method, which has been attracting attention in recent years, pressure is applied to toner made of a pressure-sensitive substance such as paraffin, wax, rubber-like soft polymer, etc. to fix the toner. In this case, usually 20 to 4
A pressure of 0 KB/ci is applied to the toner to reduce the viscosity of the toner and force it into the fibers of the paper to fix it.

These six types of equipment have great advantages in that they do not require a heat source and no warming up time, but they are
- The drawback that the fixing properties of the toner is not sufficient has not yet been solved.

In addition to the fixing method described above, a back heating roller fixing device has been proposed which heats the back side of the toner image surface of the support to melt the toner in the toner image through the paper and fix it. ing. This method utilizes the natural fluidity of the toner to fix the image, so the heating roller does not come into direct contact with the toner image, eliminating drawbacks such as offset from the heating roller. Therefore, it is considered to be a relatively effective method.

For example, an example of the above-mentioned back heating roller fixing device is disclosed in Japanese Patent Application Laid-Open No. 48-75042. This is as shown in FIG. 17, and the fixing device 30 is provided with an internal heating element 5 such as an infrared lamp inside the heating roller 1, and the roller is heated by the heat of the internal heating element 5. I am using something like this. Further, a shallow groove is provided in the longitudinal center of the surface of the heating roller 1, and the tip of the peeling claw 27 engages with the shallow groove to peel the paper.

Furthermore, a charging corotron 24 applies charges of either positive or negative polarity to the surface of the roller, and a paper charging corotron 25 applies charges to the paper in contact with the roller. The structure is such that an electric charge having a polarity opposite to that of the charging cotron 24 is applied, and the electrostatic force of the electric charge ensures that the paper adheres to the roller surface.

In the above-mentioned apparatus, a toner image is transferred from the fl image transfer section (not shown) onto the surface of the paper, is transported by the transport 28, and the back surface of the paper is brought into contact with the heating roller 1, and the paper is moved against the roller. Attracted electrostatically.

Then, while the paper is being rotated together with the heating roller 1,
Heating [] - Heat is applied by an internal heating element 5 provided inside the sheet 1, and the toner of the toner image formed on the surface of the paper is melted and fixed.

In this back heating roller fixing vtffi, since the roller does not come into contact with the surface of the paper onto which the toner image is transferred, there is no risk of image distortion and it is possible to make excellent copies with good resolution.

Then, the sheet that has been fixed is peeled off by inserting the tip of the peeling claw 27 into the groove of the roller, guided to the ejection row 526 via the paper guide 22 and the guide plate 29, and stored in the ejection tray.

Further, the surface temperature of the heating roller 1 is measured by a temperature sensor 23 such as a thermistor, and the heating of the internal heating element 5 is adjusted according to the measured value, and the surface humidity of the heating roller 51 is set. Make sure to maintain the value.

The back heating roller fixing device configured as described above reliably prevents problems such as smoking and ignition of copy paper, which are major problems with radiant type fixing devices, and also Unlike the heat roller method, the molten gutter does not offset the heating roller, so there is no need to provide a means for applying a mold release agent such as oil close to the heating roller. It is said to be advantageous.

(Problems to be Solved by the Invention) However, the above-mentioned back heating roller fixing device heats the paper from the back side and heats the toner indirectly, so it has problems in terms of fixing speed, etc. It has the disadvantage that it is difficult to obtain high-speed aptitude.

In addition, in this method, the toner is fixed by the natural flow of the toner, so the fixing surface has characteristics such as becoming rough and not mirror-like, making it impossible to adapt to color copying. There are drawbacks.

In addition, in the back heating roller fixing device, when trying to fix water-containing paper that contains a lot of water, the paper contacts the high-temperature heating roller and the contact surface is rapidly heated. Water vapor generated from the paper is interposed between the heating roller and the paper. As a result, the paper does not contact the surface of the heating roller accurately, and the heating of the space created by the hot water becomes unstable, resulting in a serious problem for customers in which fusing is not performed uniformly. This is what we are doing.

(Object of the Invention) The present invention is intended to eliminate the drawbacks of the conventionally used rear heating roller fixing device as described above. At the same time, the fixing speed is increased and the toner image metal body is heated uniformly by Vt'? The aim is to provide l.

(Means and Effects for Solving the Problems) The fixing device for an electrophotographic copying machine of the present invention is a device that fixes the toner onto the paper by bringing a heating member into contact with the back surface of the paper carrying the transferred toner. , a heat pipe is provided between the position where the heating member contacts the paper and the position where the heating member peels off the paper, and the toner image is pressed by the heat vibration to rapidly cool the toner image.

Further, in the fixing device for an electrophotographic copying machine of the present invention,
A cooling device is provided in the part of the heating member that does not come into contact with the paper, and an internal heating element is provided in a position away from the part of the heating member that first comes into contact with the paper, and after the paper is brought into close contact with the heating member,
The fi action is performed.

Furthermore, a suction device is provided inside the heating member, and an internal heating element is provided in the part before contacting the paper, and a large number of small holes are provided on the surface of the heating member, and the paper is sucked through the small holes and heated. It is configured to be brought into close contact with the surface of the member.

In addition, in the fixing device for an electrophotographic copying machine of the present invention, it is possible to use a heating belt as the heating member, and an internal heating element is provided for the heating belt, and a paper conveyance section is provided with an internal heating element. A suction member for suctioning the paper is provided so that the paper can be heated with a contact spoon on the surface of the heating belt.

Therefore, in the fixing device for an electrophotographic copying machine of the present invention, in order to improve the fixing performance of a color image, the heat pipe that contacts and presses the toner image imparts gloss to the image, as well as imparts gloss to the toner image. It can be fixed by smoothing the surface and enables fast fixing.

In general, since the fixing device for an electrophotographic copying machine of the present invention includes a suction device for suctioning the heating roller or the heating belt, it is possible to bring the paper into close contact with the surface of the heating member. As a result, the toner image can be heated uniformly and can be fixed in a good condition.

(Example) The structure of the fixing device for an electrophotographic copying machine of the present invention will be described according to the illustrated example.

First, FIG. 1 shows an example of a copy to which the present invention is suitably applied. In the copying machine shown in FIG. 1, a charging corotron 32, an exposure lamp 33, a light focusing optical system 34, a developing device 36, a transfer device 36, a photoconductor drum 31, a charging corotron 32, an exposure lamp 33, a light focusing optical system 34, a developing device 36, a transfer device 36, a photoconductor drum 31, etc. A corotron 37, a stripping corotron 38, a static eliminator 39, and a cleaning device 40 are provided.

The paper transport system includes a paper feed cassette 41 that stores paper, a paper feed roller 42 that carries out the paper 20 from the paper feed cassette 41, and a timing control for toner images formed on the photoreceptor drum 31. Match paper 20
A timing roller 44 is provided for sending out the image toward the image transfer area.

Further, in order to perform a fixing action on the paper onto which the toner image has been transferred, a fixing device fif30 is provided following the image transfer portion, and the fixing device v! A discharge tray 45 is provided after I30.

In the copying machine configured as described above, the photosensitive drum 31 is rotated in the direction of arrow A, and its surface is uniformly charged by the charging corotron 32. Then, the image of the original on the original platen 35 is irradiated with the exposure light lamp 33, and the reflected light of the image is irradiated onto the surface of the photoreceptor drum 31 via the light focusing optical system 34, and an electrostatic image is formed thereon. form. Thereafter, toner is supplied from the developing device 36 to visualize the latent image as a toner image.

The visualized toner image is transferred to the paper 20, which is fed in at the same time as the image, by a transfer roller []]1.
- The transfer is performed by the ron 3, the peeling is performed by the peeling corotron 38, and the sheet is conveyed toward the constant '4Mff13O.

Then, in the fixing device 30, the paper is heated from the wide side to complete a copy, and is ejected to the ejection tray 45. Further, after the image transfer is completed, the photosensitive drum 31
The residual charge is removed from the surface by a static eliminator 39,
The toner remaining on the surface of the photosensitive drum is removed by a brush or the like of the cleaning device 40, and the photosensitive drum is ready for the next copy cycle.

The first embodiment of the present invention shown in FIGS. 2 and F2A uses a heating roller 1 and a heat vibrator 16, and a paper 20 is sandwiched between both rollers. In this embodiment, a heating roller 1 is formed hollow, and an internal heating element 5 such as a halogen lamp is provided inside the heating roller 1.

The heating row 51 is constructed by covering the surface of a metal core 2 made of aluminum or the like with an elastic layer 3 formed of a silicone rubber layer or the like with a thickness of 2 to 3 III. The surface temperature of the heating roller 1 is maintained at a constant value by detecting the heating temperature by a temperature sensor 23 and inputting it to the control device of the copying machine.

A charging corotron 24 is provided around the heating roller 1, and a paper charging corotron 25 is provided at a position where the paper 20 is attracted. Then, by applying a voltage of opposite polarity to these charged rollers 24 and 25, opposite charges are supplied to both the heating row 51 and the paper 20, thereby causing the paper 20 to be transferred to the heating row 51. The surface is electrostatically attracted and held.

Paper guides 22, 22a are provided before and after the paper conveyance path of the heating roller 1, and the paper is guided by the paper guides. A heat vibrator 16 is provided in contact with a portion of the heating roller 51 near where the paper 20 is peeled off.

This heat vibe 16, as shown in FIG. 2A,
It is configured as a member longer than the heating roller 51, and is adapted to protrude from the portion that contacts the heating roller 1 to the side thereof.

Heat vibrator 16 used in the fixing device of the present invention
In this method, a conventionally known heat vibrator configured in the form of a roller was used, and the heat vibrator absorbed heat at the portion facing the heating roller 1, and the heat was projected to the side of the fixing device. I try to release it from the part.

In addition, the portion of the heat vibrator 16 that protrudes laterally from the heating roller 1 is made to protrude laterally from the casing of the fixing device so that it is exposed to the wind from the fan installed inside the copying machine, and its cooling effect is Therefore, it is not necessary to provide a special cooling device for the heat vibrator 16.

Next, the operation when performing fixing using the above-described back heating roller fixing device will be described. First, in the previous process, toner painting (
! ! ! The paper 20 on which the image 21 has been transferred passes through the paper guide 22 and its side is attracted to the surface of the heating roller 1. In this case, the surface temperature of the heating roller 1 is heated to a set temperature by the internal heating cord 5,
The toner image 21 is heated via the paper 20, and is conveyed toward the discharge side as the pressure roller 1 rotates in a state in which the toner is melted.

Thereafter, the fused toner image contacts the heat vibrator 16 and is rapidly cooled.
subject to the effects of oppression. As a result, the toner image 21 is pressed by the bolts of both rollers, so that it is crushed and formed to have the same roughness as the surface of the heat vibrator 16 .

In this state, the toner image surface is smoothed compared to the case of natural flow of toner, and as in the case of conventionally used fixing devices, there is a gap between the heating roller and the pressure roller. When the heat vibrator is held between The image will also be formed in a specular shape.

In the case of the above embodiment of the present invention, as shown in FIG. However, since the toner image 21 on the paper 20 is cooled by the heat vibrator 16 and has a high viscosity, the toner image 21
It will not stick to the surface of the heat vibrator 16.

Therefore, in the fixing device for an electrophotographic copying reed according to the present invention, the paper 20 is naturally separated from the heat vibrator 16 without using a peeling claw unlike the conventionally used fixing device. The 1111 paper 20 is sent out to the discharge roller 26 through the paper guide 22a.

The graph in FIG. 3 outlines changes in the surface temperature of the heating roller 1 and the interface temperature between the toner image and the paper 20 in the fixing load for an electrophotographic copying machine of the present invention. As seen in this graph, the toner is first heated by the heating roller 51 and reaches the lowest fixing humidity, but is then cooled by contacting the heat roller and its temperature drops to below the melting temperature. In addition, the surface temperature of the pressure roller 51 is rapidly lowered by contacting the heat roller, but after the paper is peeled off, the temperature rises rapidly because it is heated by an internal heating element. Then, the temperature is raised to the melting temperature of the toner, and the toner is heated again.

4 is different from that shown in FIG. 2, in that the heating roller 1 is heated via the external heating roller 7 without providing an internal heating element inside the heating row 51. ing. Further, the temperature of the external heating roller 7 is controlled by using a temperature sensor 23 to maintain the surface temperature of the external heating roller 7 at a constant value, and to maintain the heating roller 1 in contact with it at a predetermined humidity. .

This apparatus is also provided with a heat roller 16 to cool the toner image, thereby making it possible to press the image surface.

For example, in the case of the configuration shown in FIG. 2, the metal core 2 is heated by the internal heating cord 5 inside the heating roller.
The interface temperature between the heating roller 1 and the elastic layer 3 becomes extremely high, and the adhesive strength at that part rapidly deteriorates, shortening the life of the heating roller. However, as shown in FIG. When the metal core 2 is heated to a predetermined temperature, the metal core 2 does not reach a high temperature even if the surface temperature of the elastic layer 3 is heated to a predetermined temperature, so the above-mentioned problem does not occur.

In the fixing device shown in FIG. 5, a heating belt 10 is used instead of the heating row. This heating belt 10
A heating device is provided in the middle of the contact surface with the paper. This heating device is composed of an internal heating element 5 and a reflector 6, and heats the heating belt 10 from the bottom surface. The heating temperature for the paper is controlled. Therefore, in the case of this embodiment, since the heat capacity of the heating belt 17 is relatively small, the temperature of the heating device described above can be easily controlled in accordance with the above-mentioned conditions. , it is not necessary to perform that control.

In the case of this embodiment, a plurality of heating devices are provided to heat the paper conveyed on the heating belt 10 to melt the toner image, and then cool it with a heat coat 516 to make a copy. I am trying to complete it as follows.

In the second embodiment of the back heat fixing device shown in FIG. 6, the heating device does not heat the entire heating roller 1, but instead heats the heating roller 1 at a position away from the portion of the heating roller 1 that contacts the paper. It is said to be constructed in such a way that it performs an action.

In this embodiment, the heating device is composed of an internal heating element 5 and a reflector 6, and the heating device is provided inside the heating roller 1. Although the heating roller 51 rotates, the heating device is fixed. It is meant to be retained. Further, a peeling claw 2 is provided around the heating roller 1 in the direction of rotation thereof.
7. Temperature sensor 23, roller cooling device 17 are provided in sequence, and after contacting the paper 20 and heating the [・ner image @ 21], the roller cooling device 17 lowers the temperature of the surface. , the temperature of the contact portion with the next sheet 20 is lowered.

The reason why such a configuration is used is that when the surface temperature of the heating roller 1 is set high, when the paper 20 comes into contact with the paper, the moisture contained in the paper evaporates rapidly, and the water vapor is heated to 0- Since it may accumulate between the insulator layer 3 of 51 and the paper 20 and interfere with the adhesion of the paper to the insulator layer,
This is to ensure that such a situation can be prevented from occurring.

Regarding the fixing action of the fixing device shown in FIG.
This will be explained based on the figure and FIG. 7A.

Although FIG. 7 shows the cooling bag 'Fi 17 and the temperature sensor 23 omitted, the following description will be made assuming that these members are provided.

The heating roller heated by the heating device creates a dove pattern on the surface of the wA20 due to its heating action.
21 is melted and fixed. Thereafter, the paper 20 is peeled off, and its surface temperature is detected by the temperature sensor 23. Then, according to the detected temperature, the roller cooling device 17 operates to lower the roller surface temperature. Thereafter, the surface of the roller is charged by the charging corotron 24 to prepare for suction of the next sheet.

The paper 20 fed through the paper guide 22 is
It comes into contact with the heating roller at the point indicated by , and its surface charge causes an attraction operation, and roughly speaking, the paper charging corotron 25 supplies an electrical charge with the opposite polarity to that of the roller, thereby causing the attraction and holding. be ensured.

In this case, where the paper first contacts the rollers,
Since the surface temperature of the roller is kept low, even in the case of water-containing paper containing a large amount of water, water vapor is prevented from being rapidly generated. As the heating roller 1 rotates, heating is performed by the internal heating element 5 of the heating device, so that the temperature gradually rises from two points;
The toner image on the paper 20 is melted and fixed,
At point t3, the paper 20 is peeled off by the peeling claw 27.

Further, when this fixing device is used, the state of heating the sheet is as shown in FIG. 7A.

In other words, in the case of the conventional fixing device shown by the chain line in this figure, the paper is heated rapidly at the part where it comes into contact with the heating roller, and the temperature of the paper rises rapidly at the mouth. In the case of this example, the temperature rises relatively slowly, and a large temperature change compared to the environmental temperature θa is unlikely to occur. Then, while the paper moves with the rollers,
As shown by the solid line, the toner image is gradually heated and reaches the water vapor generation temperature θr after passing the point ℃2, and reaches the lowest toner fixing temperature θ'' near the peeling position t3, so that the toner image is reliably fixed. It turns out.

Furthermore, in the above-mentioned fixing device, since the adhesion between the paper and the heating roller is maintained well, when the paper is heated, the water vapor generated from the paper is removed from the toner image recording side of the paper. Since only the particles are scattered, they do not interfere with the adhesion of the paper.

In addition, as shown in the first embodiment of the present invention, a heat roller is provided before the part where the paper is to be peeled off, and is configured to apply pressure to the fused toner image. In addition to achieving a mirror finish, it is also possible to improve the peelability of the paper and omit the peeling claw 27.

In another embodiment of the invention shown in FIG.
In place of the cooling device 17 shown in the figure, a cooling device using a heat roller is used. In this case, the configuration of the cooling device can be made simpler than in the case of cooling using an air blower, and furthermore, the cooling efficiency can be improved.

In the case of the embodiment shown in FIG. 9, a heating belt 10 is used instead of the heating row. This heating belt 10
In this example, an insulating layer 12 of a predetermined thickness is integrally formed on the surface of a metal belt 11, and the heating belt 10 is configured in an endless shape. Then, the heating belt 1o is passed over a pair of driving rows 515.15 to drive the belt, and a heating device of a predetermined temperature is provided at the lower part of the conveying surface of the belt, and the heating device is connected to the internal heating element 5 and the reflector. -6, and heats the heating belt 10.

Further, a temperature sensor 23 is provided at a predetermined portion of the return path of the heating belt 10, and the temperature is detected by the temperature sensor 23, and the belt cooling device 17 performs cooling. Therefore, according to this method, it is easy to adjust the fixation level once, and it is also possible to bring the paper into contact with the belt over a relatively long period, so the fixation can be carried out while moving the paper at high speed. Action 1!
It becomes possible to configure the device as a device that In addition to this,
As in the case of a general fixing device using the heating belt 10,
Since the fluidity of the toner can be maintained well, it can be easily applied to color copies.

In an alternative embodiment of the invention, shown in FIG. 10, instead of electrostatically attracting the paper, a suction device 18
A method of suction is used.

In the fixing device shown in FIG. 10, a heating roller 1 is formed of a metal core 2 and an insulating layer 3, and as shown in the figure, a large number of small holes 4 are provided so as to pass through the heating roller. ing.

Further, a heating device composed of an internal heating element 5 and a reflector 6 is provided inside the heating roller, and a suction device 18 is also provided to suck air to the portion where the paper contacts the heating roller 1. By the suction, the water vapor generated from the water-containing paper is sucked, and the paper is adsorbed to the surface of the O-La, so that the paper is brought into close contact with the surface of the paper without any gap between them.

In this embodiment, the heating roller is heated at a position before the part where the paper 20 contacts the heat roller 1, and the paper comes into contact with the heated roller surface, and the paper 20 contacts that part. Even if water vapor is generated, the suction device 18
By suctioning the paper, it is possible to prevent water vapor from accumulating between the roller surface and the paper, and to maintain good adhesion of the paper.

Further, as shown in FIG. 11, the heating roller 1 includes:
A large number of small holes are provided throughout the structure, and as shown in FIG. 11A, which is an enlarged view of a portion of the holes, they penetrate through the metal core 2 and the insulator layer 3 (thickness: 30 μm). The small hole 4 is formed in this state.

In the heating roller 1 as shown in FIGS. 10 and 11, the diameter of the small holes 4 is 1 cocoon, and the interval between the holes is 2 mm.
A fixing test was conducted using a substantially mesh-shaped heating roller.

When we conducted a fixation evaluation test using styrene acrylic toner as the toner, we found that the heating roller set temperature was 1.
Good fixing without uneven fixing was possible at 80° C. and when the time the paper was in contact with the heating roller was 1 second.

In addition, in this embodiment, the paper is brought into close contact with the roller surface by air suction, but the paper is peeled off after the fixing is completed due to the elastic recovery force of the paper, so the peeling claw It is not necessary to provide Further, since the temperature υItll of the heating roller is determined by the heat generation aQ of the internal heating element 5 and the surface V4S of the opening of the reflector 6, the energy supplied to the heating roller is not required. .

Another embodiment of the present invention shown in FIG. 12 and subsequent figures is an example in which a heating belt is used.

First, in the example shown in FIG. 12, the toner image 21 formed on the photoreceptor drum 31 is transferred by a transfer roller 37, peeled off by a peeling corotron 38, and passed through a paper guide 22 to a fixing device. move it to

This fixing device is constructed by passing a heating belt 10 around a pair of drive rollers 15, 15, and a predetermined number of heating devices are provided in the middle of the conveying section.

As this heating device, a device consisting of an internal heating element 5 and a reflector 6 is used, as in the above example,
The heating device is provided in parallel around a plurality of circumferences to heat the required section of the heating belt.

In this embodiment, the heating belt 10 is replaced by a metal belt 1.
1 and the insulating layer 12 are formed as an integral member, and the metal belt 11 has a diameter of 0.1 to 0.9.
The insulator layer 1 is made of a metal material such as aluminum with a thickness of about 2 mm, and a layer made of a heat-resistant resin such as fluororesin or silicone rubber is formed on the surface of the insulator layer 1 with a thickness of about 30 μm.
2 is provided in one piece.

Further, a belt charging corotron 24 and a paper charging corotron 25 are provided at a predetermined position δ of the fixing device. A voltage of approximately +5 V to V is applied to the corotron, thereby imparting charges of opposite polarity to both members, so that the paper is attracted to the heating belt 10 by static electricity.

In the heating belt 10 shown in FIG. 12, small holes 4 are provided throughout the belt as shown in FIGS. 13 and 14, and the heat dissipated to the outside through the small holes 4 Alternatively, it is also possible to heat the paper and heat the toner image @21 through the paper 20 to improve its fixing efficiency.

In the example shown in FIG. 15, instead of using the internal heating element 5 and the reflector 6 as the heating device, a heating roller 14 having a different configuration is used, and the metal belt 11 is connected to the heating roller 14 and the drive roller 515. It is designed to drive by winding it around the

This heating roller 14 is provided with an internal heating element 5 inside the drive roller, and uses the heat to heat the roller and transfer the heat to the belt wound around the row.
The temperature is detected by temperature sensors 23 and 23 provided for the belt 11 and the heating row 514, respectively, to control the heating.

Furthermore, in this embodiment, a suction device 18 is provided on the lower surface of the belt conveyance section, and the paper is attracted by the suction force of the suction device 18, thereby bringing the paper into close contact with the metal belt 11. Vru. In this type of fixing device, since it is not necessary to charge using a charging corotron, the charging corotron can be omitted. Therefore, it is not necessary to provide a peeling claw, etc., and an insulating layer is not provided. Instead, only the metal belt is used, and the heat from the heating roller 14 is transmitted to the paper via the metal belt 11 to melt the toner image.

Furthermore, in this example, the paper is automatically separated from the metal belt 11 when the suction by the suction device 18 is finished, so that the configuration can be simplified.

Another embodiment of the invention, shown in FIG. 16, provides for heating the heating belt 10 using a plurality of heating rollers 14,14. The heating row 514 used in this embodiment uses a member having the same structure as in the embodiment shown in FIG. 15, and the heating temperature is controlled for each heating row 514. This is done via the temperature sensor 23. In addition, the heating belt 10
In this case, a member in which a metal belt 11 and an insulating layer 12 are laminated is used.

Then, the heating belt is charged by the belt charging corotron 24, and the paper is charged by the paper charging corotron 25, so that the paper 20 is attracted to the belt by static electricity.

Further, in this embodiment, a small-diameter drive roller 15 is provided at the ejection section from the fixing device, and the heating belt is curved rapidly, so that the paper 20 is automatically peeled off by utilizing the elasticity of the paper. The system adopts a configuration that allows for therefore,
It becomes possible to provide a device that easily peels off paper by the kerf strip action without providing a peeling claw.

In these embodiments of the fixing device of the present invention, especially in the case where a heating belt is used, it is easy to set a long distance for heating the paper, so that the toner image is melted well. It is something that can be done.

Roughly speaking, in the embodiments of the present invention shown in FIGS. 6 and after, a heat roller may be provided at the final part of the +8 melting process of the toner to press the toner image and form a mirror-like copy. Since it can be done relatively easily, the fixing device of the present invention can be easily applied to color copies as well.

In addition, in the fixing device of the present invention, since the contact distance between the heating device for heating the paper and the paper can be set long, the heating time can be set to 1 minute, which is similar to the case of color copying. In addition, it becomes possible to reliably melt the toner, and it becomes possible to sufficiently mix the color toners formed in layers and to perform color development in a good state.

(Effects of the Invention) Since the fixing device for an electrophotographic copying machine of the present invention has the above-described configuration, it is possible to heat the paper onto which the toner image has been transferred for a relatively long time. By heating, it is possible to melt the toner in a good state, and by simply adding a heat vibrator, it is possible to obtain an existing device suitable for fixing color images.

Furthermore, in the back heat fixing device of the present invention, even when using water-containing paper, it is possible to reliably prevent the effects of the generation of water vapor, and to bring the paper into good contact with the heating member and toner images. Can be heated evenly.

In addition, in the fixing device of the present invention, since it is possible to use a heating belt, it is possible to heat the paper while it is attracted to the belt, thereby increasing the running speed of the paper. Also, the toner image can be sufficiently heated, thereby making it possible to sufficiently cope with the high speed copying machine.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the configuration of a copying machine to which the present invention can be applied, FIG. 2 is an explanatory diagram showing the configuration of a rear heat fixing device using a heat pipe, FIG. 2A is a front view thereof, and FIG. 3 is a graph showing the state of temperature change in the device including the back heating chamber of the present invention, FIG. 4 is an explanatory diagram showing an example in which an external heating roller is used, and FIG. 5 is an example in which a heating belt is used. FIG. 6 is an explanatory diagram showing the configuration of another embodiment of the present invention when a cooling device is used; FIG. 7 is an explanatory diagram showing the fixing operation in the apparatus shown in FIG. 6; Fig. 7A is a graph showing the state of temperature change at each point corresponding to Fig. 7, Fig. 8 is an explanatory diagram showing an example of a device using a heat pipe as a cooling device, and Fig. 9 is an explanatory diagram showing an example of a device using a heat pipe as a cooling device. An explanatory diagram showing an example of a heating belt, FIG. 10 is an explanatory diagram showing the configuration of another embodiment of the present invention configured to suck paper using a suction device, and FIG. 11 is an explanatory diagram showing a heating belt according to the present invention. A perspective view of the roller; FIG. 11A is an enlarged perspective view of a portion of the heating roller;
FIG. 2 is an explanatory diagram showing the configuration of the fixing device when a heating belt is used, FIG. 13 is a perspective view showing the configuration of the heating belt shown in FIG. 12, and FIG. FIG. 15 is an enlarged perspective view, and FIG.
FIG. 6 is an explanatory diagram of a fixing device using a heating belt when a plurality of heating rollers are used, and FIG. 17 is an explanatory diagram showing the configuration of a conventionally used back heating roller fixing device. Reference numeral 1 in the figure: heating roller, 2: metal core,
3...Insulator layer, 4...Small hole, 5...
...Internal heating element, 6...Reflector-1
7...External heating roller, 10...Heating belt, 11...Metal belt, 12...
・Insulator layer, 13...Small hole, 14...
Heating roller, 15... Drive roller, 16...
... Heat pipe, 17 ... Cooling device, 18
...Suction device, 20...Paper, 21.
...Toner drawing &, 22...Paper guide,
23...Temperature sensor, 24...Charging corotron, 25...Paper charging corotron, 2
6...Discharge roller, 27...Peeling claw,
28...Transport, 29Figure 3Figure 10Figure 11AFigure 16

Claims (4)

[Claims] (1) In a back side heating fixing device that fixes the toner to the support by bringing a heating member into contact with the back side of the support carrying the transferred toner, a position where the support comes into contact with the heating member;
A fixing device for an electrophotographic copying machine, characterized in that a heat pipe for pressing a toner image is provided between a peeling position and a peeling position. (2) A cooling device is provided in a part of the heating member that does not come into contact with the support, and an internal heating element is provided in a position away from the part of the heating member that first comes into contact with the support, and after the support is brought into close contact with the heating member. 2. The fixing device for an electrophotographic copying machine according to claim 1, wherein the fixing device is configured to perform a heating action. (3) A suction device is provided inside the heating member, an internal heating element is provided in the part before contacting the support, and a large number of small holes are provided on the surface of the heating member, and the support is sucked through the small holes. 2. The fixing device for an electrophotographic copying machine according to claim 1, wherein the fixing device is configured to be brought into close contact with the surface of the heating member. (4) A device using a belt is provided as a heating member, an internal heating element is provided for heating the heating member, and a suction member for adsorbing the support is provided in the conveyance section of the support. A fixing device for an electrophotographic copying machine according to claim 1, characterized in that: