JPS6191678A - Fixing device for electrophotography - Google Patents

Abstract

PURPOSE:To reduce thermal loss during preheating by providing a reflecting mirror for preheating which converges radiant rays from an infrared-ray source on the irradiation end part of a flash fixing means in a slit shape as a preheating means. CONSTITUTION:The reflecting mirror 6 does not disperse and projects infrared rays for preheating from the infrared-ray source 5 on paper 4 to relatively wide area, but converges them only on the irradiation end part S in the slit shape. Further, the infrared-ray source 5 uses an infrared-ray source which generates radiant rays in the far infrared range of about >=2mum wavelength so that energy is absorbed efficiently by paper 4 and toner 8, e.g. far- infrared-ray heater 5. When the paper 4 having toner 8 stuck is conveyed as shown by an arrow and passes through the irradiation end part S right before entering a flash fixing device 3, the radiant rays from the infrared-ray source 5 are converted on the irradiation part S in the slit shape through the reflecting mirror 6 for preheating, so the radiant energy of the radiant rays is absorbed efficiently by the paper 4 and toner 8, which are conveyed immediately to a flash fixing device 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an electrophotographic fixing device that forms images using an electrophotographic method, and particularly relates to an improvement of a flash fixing device suitable for copying machines, printers, and the like.

[Background of the invention]

Generally, in electrophotographic copiers and printers, after forming an electrostatic latent image on a photoreceptor, developing powder called toner is deposited on the electrostatic latent image to form a toner image. Transfer to paper. Next, by passing the transferred paper through a fixing device, D) the toner image was fused to the paper.

In the 7-flash fixing method, a flash discharge lamp such as a xenon flash lamp is usually turned on momentarily and high-energy radiation is irradiated to heat and fuse the toner image to the paper. In this case, the wavelength of the flash light is 0.4
to 1.0 μm, the absorption rate of radiant energy of paper (white paper) is small at less than 20%, whereas toner exhibits a good absorption rate independent of wavelength, almost the same as a completely black body. , which has the feature of heating the toner without raising the temperature of the paper.

However, on the other hand, in the case of a toner image in which toner particles are sparsely isolated, the heat loss is large, and the fixing performance varies depending on the density of the toner image. There was a tendency for insufficient fixation.

As a technique to eliminate this drawback, Japanese Patent Application Laid-Open No. 52-110
As described in Japanese Patent Application Publication No. 050 and Japanese Patent Application Laid-Open No. 58-216274, before a paper on which toner has been developed is placed in a flash fixing device, a relatively large area of the paper is irradiated with infrared rays. However, techniques have been devised to preheat the paper and toner images.

However, in the case of preheating described above, little consideration is given to heat loss during preheating. , heat loss due to heat conduction from the infrared irradiated surface of the paper to the back side of the paper is likely to occur, and especially when the paper is thick, the power required for the infrared source is large in order to preheat the paper and toner to the desired temperature. There was a tendency to become weaker.

[Object of the Invention] An object of the present invention is to provide an electrophotographic flash fixing device that eliminates the above-mentioned drawbacks and is capable of efficient and stable fixing.

[5 Summary of the Invention] By a preheating means including an infrared source and a preheating reflector,
In an electrophotographic fixing device that preheats paper with toner on it and then transports the paper to a flash fixing device for fixing, there is a certain amount of time that elapses from the time the paper is preheated until the paper is fixed by the flash. , during which a loss of preheated heat occurs. The degree of this loss varies depending on the concentration of toner, its distribution on the paper, and the thickness of the paper itself, but in all cases, the longer the above-mentioned time, the greater the heat loss. The present invention focuses on this point in time, and the preheating means includes a preheating reflector configured so that the radiation from the infrared source is focused in a slit shape on the irradiation end of the flash fixing device. It was designed to be equipped with the following. With this configuration, the preheated paper and toner are transported into the seven-lash fixing device in the shortest possible time, and stable fixing performance can be obtained.

[Embodiments of the invention]

FIG. 1 is a side view of an embodiment of the seven-lash fixing device of the present invention. In the figure, numeral 3 denotes a flash fixing device comprising a tubular flash lamp 1, a flash fixing reflector 2, and the like.

4 is toner 8 attached (adhered after development n1)
Paper is transported in the direction of the arrow in the figure.

5 is a tubular infrared ray source that preheats the paper 4 and toner 8. Reference numeral 6 denotes a preheating reflecting mirror that irradiates infrared rays radiated from the infrared a source 5 onto the transported paper 4 and the toner 8 attached thereto to preheat them.

S is a relatively narrow and elongated slit-shaped portion on the paper 4 along the outer edge of the flash fixing reflector 2 in a direction perpendicular to the conveying direction of the paper 4 (hereinafter referred to as the irradiation end portion). shows.

The reflecting mirror 6 is configured so that the preheating infrared rays from the infrared source 5 are not distributed and irradiated onto a relatively wide area of the paper 4, but are condensed and irradiated only on the irradiation end S in a slit shape. ing.

Further, as the infrared source 5, an infrared source that generates radiation in the far infrared region with a wavelength of about 2 μm or more, such as a far infrared heater, is used so that the paper 4 and the toner 8 can efficiently absorb energy. .

In the above-mentioned configuration, the paper 4 to which the toner 8 is attached is conveyed in the direction of the arrow in the figure, and passes through the irradiation end S immediately before entering the flash fixing device 3.

Since the radiation from the infrared source 5 is focused in a slit shape on the irradiation end 8 by the preheating reflector 6, the paper 4 and the toner 8 efficiently absorbed the radiant energy of the radiation. Afterwards, it will be immediately transported into the flash fixing device 3.

Therefore, in the preheated paper section, heat loss due to heat conduction from the front surface of the paper 4 to the back surface is less likely to occur, and only the toner 8 and the surface of the paper 40 are heated to the necessary and sufficient temperature, so especially when the paper thickness is It has the advantage of being able to reduce heat loss during preheating, which tends to increase when thicker, and stable fixing performance can be obtained.

FIG. 2 is a side view of another embodiment of the present invention; the reference numerals appearing in FIG. 1 also appear in FIG.

The difference between this embodiment and the embodiment shown in FIG. In the case of this example, the temperature of the reflecting plate that is also used tends to increase, but this has the advantage that the entire fixing device can be further downsized.

FIG. 3 shows a plan view of yet another embodiment of the invention.

The symbols are the same as in FIGS. 1 and 2. The point 1-4 in the configuration is that the flash lamps 1 are arranged in parallel in the conveyance direction of the paper 4. Also in this example, the infrared source 5 and
By arranging the preheating reflector 6 that condenses infrared rays into a slit shape adjacent to the flash fixing device 3, the same effects as in FIGS. 1 and 2 can be obtained.

The preferred embodiments of the present invention have been described in detail above by way of example with reference to the drawings. However, one type of shape of the purchased parts described in these examples.

Unless otherwise specified, the relative arrangement, etc.
The scope of this invention is not limited to those only,
This is just an illustrative example.

Although FIGS. 1 and 2 show the case where the number of flash lamps 1, infrared ray sources 5, etc. are in the number of threats, it goes without saying that the present invention can also be applied to a case where there are a plurality of these.

In addition, in the embodiment, the shape of the radiation from the irradiation end S and the infrared ray source 5 condensed thereon is shown as a linear slit, but this shape also depends on the shape of the flash fixing device 3, for example. It can be appropriately deformed into an arch shape or a polygonal shape.

〔Effect of the invention〕

As explained above, the present invention includes a preheating reflector formed in a slit shape at the irradiation end of the flash fixing means to condense the radiation from the preheating infrared source. (1) Heat loss during preheating can be reduced, and even when the paper used is thick, efficient preheating is possible.

(2) Since the paper and toner can be preheated at the same time immediately before the flash fixing device, almost the same fixing performance (fixing strength).

(3) Preheating efficiency is high and preheating heat loss is small, so
By reducing the flash energy, you can extend the life of the flash lamp.

(4) The power required for the device is reduced and it becomes easier to downsize.

[Brief explanation of the drawing]

FIG. 1 is a side view of one embodiment of the present invention, FIG. 2 is a side view of another embodiment, and FIG. 3 is a plan view of still another embodiment. DESCRIPTION OF SYMBOLS 1... Flash lamp, 2... Flash fixing reflector, 3... Flash fixing device, 4... Paper, 5...
... Infrared source, 6... Reflector for preheating, 8... Toner, S... Irradiation end.

Claims (1)

[Scope of Claims] 1. In an electrophotographic fixing device comprising a preheating means provided with an infrared source and a flash fixing means, the preheating means is arranged such that the radiation of the infrared source is applied to an irradiation end of the flash fixing means. 1. An electrophotographic fixing device comprising a preheating reflector that focuses light in a slit shape. 2. The electrophotographic fixing device according to claim 1, wherein a part of the flash fixing reflecting mirror is a part of the reflecting surface of the preheating reflecting mirror.