JPH09274401A - Heating member and method and device for fixing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To instantly heat a heat resistant belt by using a heating member for fixing which includes a light absorption heating element generating heat by absorbing light. SOLUTION: The endless heat resistant belts 12 and 13 being the heating member for fixing are constituted of a base material 14 made of heat resistant transparent resin and the light absorption type heating element 16 generating the heat by absorbing the light, to put it concretely, carbon black and the like. It is good that the belts 12 and 13 are molded by an extrusion method by dispersing the prescribed proportion (for example, about 1-15wt.%) of the heating element 16 in the heat resistant transparent resin for the base material 14 and kneading them (a). It is also good that one surface of a base layer 18 consisting of the heat resistant transparent resin is provided with a heat generation layer 20 consisting of the heating element 16 or including it by heat adhesion and the like (b). Besides, it is good that the base layer 18 is made to adhere to both surfaces of the layer 20 (c). The heating element 16 instantly generates the heat by being illuminated and heats the heating member. Therefore, when a heating start instruction is given, a fixing feasible state is instantly set.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing heating member for melting unfixed toner in an image forming apparatus such as a copying machine or a printer, and fixing the melted toner on a sheet using this heating member. And a fixing device including the heating member.

[0002]

2. Description of the Related Art Conventionally, a belt type fixing device has been proposed in Japanese Patent Laid-Open No. 4-324476 as one mode of the fixing device. This belt type fixing device is generally
It is equipped with an endless heat resistant belt, a plurality of rollers that support the heat resistant belt from the inside, a pressure roller that presses against the outer peripheral surface of the heat resistant belt, and a heater that heats the heat resistant belt. The sheet is heated, and by utilizing the heat, the unfixed toner held on the sheet is melted and fixed on the sheet passing through the contact portion (nip portion) between the heat resistant belt and the pressure roller.

This belt type fixing device has a higher heat resistance than a roller type fixing device in which unfixed toner is melted and fixed on a sheet between a heating roller containing a heater and a pressure roller pressed against the heating roller. There is an advantage that the heating time of the unfixed toner can be sufficiently secured in the nip portion between the belt and the pressure roller.

[0004]

However, there is room for improvement in the above belt type fixing device, and there has been a demand for a structure capable of heating the heat resistant belt in an instant.

[0005]

The present invention has been made to provide a new heating member for fixing, a fixing method, and a fixing device which can meet such a demand, and the present invention proposed here is provided. The fixing heating member includes an absorption heating element that absorbs light to generate heat. Further, the fixing method of the present invention uses the above-mentioned heating member, illuminates a heating member including an absorption heating element that absorbs light to generate heat to generate heat, and heats and melts the toner with the heated heating member to melt the toner. The fixed toner is fixed on the sheet.

Further, the fixing device of the present invention implements the fixing method by using the heat fixing member, and illuminates the heating member including a light absorption heating element that absorbs light and generates heat, and the heating member. It is provided with an illuminating means, a conveying means for conveying the sheet having the unfixed toner to a portion facing the heating member, and a fixing means for fixing the heated and melted toner to the sheet.

[0007]

When the heating member is illuminated by the illuminating means, the absorption heating element which absorbs the light instantly generates heat. On the other hand, the sheet having the unfixed toner is conveyed to a portion facing the heating member, where the unfixed toner is heated and melted. The melted toner is fixed to the sheet by the fixing means.

As described above, the absorption heating element instantly generates heat by being illuminated and heats the heating member. Therefore, in the fixing device of the present invention, when a heating start instruction is given, the heating member is immediately illuminated and heated, and the fixing state can be set. Further, the fixing device of the present invention having the illuminating means is much simpler in structure than the fixing device using the electric heater.

[0009]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a fixing device 10 according to the present invention. Endless heat-resistant belts 12 and 13 which are heating members for fixing, as shown in FIG. 2, are made of polyimide, polyamideimide, polyetherimide, polyethersulfone, A base material 14 of heat-resistant transparent resin such as ether ether ketone, silicone resin, fluororesin,
It is composed of an absorption heat generating element 16 that absorbs light and generates heat, specifically, carbon black or the like. The heat resistant belts 12 and 13
2A, as shown in FIG. 2A, the heat-absorbing transparent resin for the base material 14 is provided with the light absorption heating element 16 in a predetermined ratio (for example, about 5 to 15
2% by weight), and the mixture may be kneaded and molded by an extrusion method. Alternatively, as shown in FIG. 2 (b), a base layer 18 made of a heat-resistant transparent resin may be composed of an absorption heating element 16 or may be formed on one side thereof. The heat generating layer 20 including the heat generating layer 20 may be provided by thermal bonding or the like, or as shown in FIG. 2C, the base layer 18 may be bonded to both surfaces of the heat generating layer 20.

The heat resistant belt 12 is supported from the inside by a driving roller 24 drivingly connected to the motor 22 and a driven roller 26 arranged in parallel with the driving roller 24. Also, a belt portion 28 extending between the drive roller 24 and the driven roller 26.
The outer peripheral surface of the belt 13, which is supported from the inside by the driven roller 25 and the driven roller 27 arranged in parallel with the driven roller 25, is in contact with the outer side of the. The driven rollers 25 and 27 are in pressure contact with the driving roller 24 and the driven roller 26, respectively (hereinafter, the contact portion between the belt 12 and the belt 13 is referred to as a "nip portion 32"). A light source 36 is provided inside the heat-resistant belt 12 so as to face the belt portion 28, and the periphery of the light source 36 is covered with a reflecting plate 38 except for the facing portion of the belt portion 28. As the light source 36, a flash type lamp such as a xenon lamp is preferable, and a light source of about 400 to 1000 n is preferable.
Those emitting m wavelengths are used. Similarly, a light source 37 and a reflection plate 39 are provided inside the heat resistant belt 13 so as to face the belt portion 29.

In the fixing device 10, the drive roller 24 rotates in the direction of arrow 40 based on the drive of the motor 22.
As a result, the heat-resistant belt 12 rotates in the direction of the arrow 42, and the driven roller 25 contacting the heat-resistant belt 12,
26, 27 and the heat-resistant belt 13 are indicated by arrows 44, 4 respectively.
It rotates in the 6 and 47 directions. Further, when the light emission command signal is applied to the light sources 36 and 37, the light sources 36 and 37 emit light. This light is illuminated by the heat-resistant belt portions 28, 29 passing through the nip portion 32 directly or by being condensed on the reflection plates 38, 39. In the illuminated heat-resistant belt portions 28 and 29,
The light absorption heating element 16 included in the heat resistant belts 12 and 13 absorbs light and instantly generates heat, and the heat resistant belt portions 28 and 29 are heated. Therefore, when the sheet 52 holding the unfixed toner 50 enters the nip portion 32 from the direction of the arrow 54 by the conveying device 48, as shown in detail in FIG. 50 is melted and fixed on the sheet 52. In the case of a flash type lamp such as a xenon lamp, light emission is instantaneous. Therefore, in order to fix the entire surface of the sheet at one time, the sheet is placed in the nip portion 3
The light must be emitted in a state of being within 2. Therefore, the nip portion 32 is set longer than the entire length of the sheet. Further, a sensor (not shown) for detecting the leading edge of the sheet is provided in front of the entrance to the nip portion 32, and a predetermined time after the detection, that is, after the sheet is housed in the nip portion 32, the light source 36, 37 is caused to emit light (see FIG. 4).

In the above embodiment, only one light source 36 and 37 is provided inside the heat resistant belts 12 and 13, but a plurality of light sources may be arranged to increase the amount of heat generation. Further, in the above embodiment, the sheet is heated from both sides, but only one side is heated (excluding the light source 37).
You may do so.

Although the reflector 38 is not essential, it has an advantage of collecting light from the light source 36 and increasing the amount of heat generated in a specific area of the heat resistant belt 12.

Furthermore, an example in which an endless belt is used as a belt-shaped member containing an absorption heating element is shown. However, a belt-like material having a delivery roll and a take-up roll and having the same quality as the heat resistant belt is wound around the delivery roll. Alternatively, the belt-shaped material fed from the feeding roll may be illuminated to generate heat, and the heat may melt the toner to fix it on the sheet. In this case, it is preferable that a supporting member such as a pressure roller is opposed to the band-shaped material in the portion where the toner is melted, and the sheet is conveyed while being sandwiched between the band-shaped material and the supporting member.

Further, the heating member including the absorption heating element may be formed and fixed in a plate shape so as to heat the unfixed toner in a non-contact manner, or the back surface of the sheet on which the unfixed toner is not held. The unfixed toner may be heated by contacting with.

Further, the unfixed toner may be preheated by the heating member, and the toner may be melted and fixed on the sheet by another heating source.

[Brief description of drawings]

FIG. 1 is a sectional view of a fixing device according to the present invention.

FIG. 2 is a partially enlarged cross-sectional view of a heat resistant belt.

FIG. 3 is an enlarged view of the vicinity of a nip portion.

FIG. 4 is a flowchart of a program for controlling light emission of a light source.

[Explanation of symbols]

10 ... Fixing device, 12, 13 ... Heat resistant belt, 14 ... Substrate, 16 ... Heating element, 24 ... Drive roller, 26 ... Followed roller, 28, 29 ... Belt portion, 36, 37 ... Light source, 3
8, 39 ... Reflector, 50 ... Toner, 52 ... Sheet.

Claims (3)

[Claims] 1. A fixing heating member including an absorption heating element that absorbs light to generate heat. 2. A fixing method in which a heating member including an absorption heating element that absorbs light to generate heat is illuminated to generate heat, the toner is heated and melted by the heated heating member, and the melted toner is fixed on a sheet. 3. A fixing device for melting unfixed toner and fixing the unfixed toner onto a sheet, a heating member including a light absorption heating element that absorbs light and generates heat, an illuminating means for illuminating the heating member, and the unfixed toner. And a fixing unit that fixes the heated and melted toner to the sheet.