JPS6159508B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a heat fixing device for a dry type electrophotographic copying machine.

This type of fixing device heats and melts the toner adsorbed or transferred onto the copy paper and fuses it to the copy paper, and the heating means uses conductive heat. Some use radiant heat. There are various types of heating means that utilize radiant heat, but they can be roughly divided into those in which the copy paper is scanned by radiation while passing through the irradiation area of the heating lamp; There is a type that simultaneously exposes the entire surface of the paper to radiation from a flash lamp for a short period of time.
The present applicant first developed a heat fixing device using this flash lamp by arranging the flash lamp on the axis inside a transparent cylinder, and rotating the cylinder while keeping the copy paper in close contact with the outer peripheral surface of the cylinder. An application was filed in which a copy paper is conveyed and radiant heat from a flash lamp is applied to the copy paper through a transparent cylinder, and the present invention relates to an improvement on the invention of the earlier application.

In the prior invention, a transparent cylinder is rotated to convey copy paper, but since this cylinder is made of glass, it is difficult to support the axis, and especially when the conveyance speed is increased, blurring occurs, and This causes image shift and uneven fixing.

The present invention aims to eliminate the above-mentioned drawbacks, and includes: a transparent cylinder rotatably supported around an axis; a radiant heat generation source disposed on the axis within the cylinder; A conveying device consisting of an endless belt that conveys copy paper in close contact with the outer peripheral surface of a cylinder,
The two front rollers that press the endless belt against the cylinder are in a fixed position and the interval between them is smaller than the diameter of the cylinder, and the endless belt is wound around the cylinder more than half a turn and pressed, and the axis of the rear roller is moved. It is characterized by being pressed into contact with the cylinder in such a manner as to obtain the desired shape.

Next, the basic configuration of the present invention will be explained using an embodiment shown in FIGS. 1 and 2.

Reference numeral 1 denotes a rod-shaped xenon lamp, which is fixedly arranged on the axis of a transparent cylinder 2 made of glass. An endless belt 3 is wound around the transparent cylinder 2 in an Ω shape. The transparent cylinder 2 is supported by three rollers 4, 5, and 6 via an endless belt 3, and is not particularly supported pivotally. As shown in FIG. 2, the shafts 7 and 8 of the rollers 4 and 5 are supported so that they can only rotate by using holes provided in a frame 9 as bearings. The shaft 10 of the roller 6 is
It passes through a long hole 11 provided in the frame 9, and can move along the long hole 11 in addition to rotating. A lever 12 is pivotally supported on the frame 9 by a shaft 13, is biased by a spring 14, and is pressed against a protruding portion of the shaft 10. The roller 6 receives the urging force of the spring 14, and
It is pressed against the transparent cylinder 2 via the endless belt 3. The endless belt 3 is wound around the transparent cylinder 2 and the rollers 4 and 5 in an Ω shape, and is also wound around the pulley 15. pulley 1
5 is driven by a motor 16 to cause the endless belt 3 to run as shown by arrow A. The transparent cylinder 2 is formed by the running of the endless belt 3.
It rotates as shown by arrow B, the axis of rotation being determined by rollers 4, 5, 6.

The endless belt 3 is run as shown in the figure, and the copy paper 19 with the toner 18 attached thereto is
When the copy paper 19 is fed along the guide plate 17, the copy paper 19 is transferred to the transparent cylinder 2 by the endless belt 3.
While being pressed into contact with the material, it is wrapped around its circumferential surface and transported. The xenon lamp 1 emits light for a short time in synchronization with the timing when the copy paper 19 is wrapped around the transparent cylinder over its entire length. The radiation emitted from the xenon lamp 1 passes through the transparent cylinder 2, is absorbed by the toner 18, and heats and melts the toner 18. Thus, the fixed copy paper 1
9 is peeled off from the circumferential surface of the transparent cylinder 2 by a peeling claw 20. The use of a glass tube in this way has a drawback of general flash fixing. Toner flying during flashing and toner layer thickness from 40μ to 20μ
There is a significant increase in thermal efficiency because it is crushed to about μ.

The embodiment shown in FIG. 3 has the above-mentioned basic structure plus necessary accessory members. A cleaning felt 21 is brought into sliding contact with the circumferential surface of the transparent cylinder 2, and removes toner adhering to the transparent cylinder 2, thereby preventing the occurrence of offset. Cleaning felt 21 contains silicone oil, wax,
It is preferable to impregnate the material with glycerin, animal oil, vegetable oil, mineral oil, synthetic oil, etc. Instead of a pad-like material, a roller-like material may be used, or a rubber roller may be used. It may also be in the form of a blade. Since toner stains also occur on the endless belt 3, a cleaning device is also provided for this. That is, 22 is a blade for scraping off toner adhering to the endless belt 3, and 23 is a felt pad. 24 is a conveyor for feeding the copy paper 19, and runs in the direction of arrow C at the same speed as the endless belt 3. The transparent cylinder 2 is
Since it does not absorb radiation, the temperature rise is small, but when used continuously for a long time, the temperature rises and toner becomes more likely to adhere. In order to prevent this, it is preferable to coat the peripheral surface of the transparent cylinder 2 with a film of fluororesin, but it is also desirable to control the temperature. A fan 25 is provided for this purpose, and blows air from the end of the transparent cylinder 2 into the interior thereof through a duct 26. Transparent cylinder 2
A temperature detector is provided inside or on the periphery of the fan 25, and the fan 25 is activated when a temperature of, for example, 50° C. or higher, or 100° C. or higher depending on the toner, is detected. If the temperature of the transparent cylinder 2 is too low, water droplets may adhere to the transparent cylinder 2, reducing its transparency. The fan 25 is also used in such cases. In that case, activate the heater installed in the air passage. In addition to installing the heater in the air duct,
7, 27', they may be placed inside or outside the transparent cylinder 2 so as to act directly on it. In order to detect the state in which the entire length of the copy paper 19 is wrapped around the transparent cylinder 2, a sensor 28 is provided near the exit of the transparent cylinder 2. When the leading edge of the copy paper 19 reaches this position, the sensor 28 detects this and activates the trigger circuit of the xenon lamp 1.

The roller that rotatably supports the transparent cylinder 2 is
In the above embodiment, there are three rollers, but as shown in FIG. 4, four rollers 4, 5, 6', 6'' may be used, or a larger number may be used. In this case , the shafts of the two rollers 4, 5 remain stationary, and the shafts of the other rollers 6', 6'' are pressed against the transparent cylinder 2. It is advantageous to select the rollers that keep the shaft immobile in order to resist the tension applied to the endless belt 3, that is, the rollers around which the endless belt 3 is wound. and roller 4,
5 may be made movable. Endless belt 3 is
It may be wide enough to cover the entire length of the transparent cylinder 2, or
Several narrow width strips may be arranged in parallel. If the endless belt 3 moves in the axial direction, that is, if it shifts, it will cause problems, so the pulley 1
5. Alternatively, it is necessary to provide means for stopping the rollers 4, 5, etc. from shifting. As the stopper means, well-known means such as providing a flange thereon or making the circumferential surface medium-height can be adopted. Providing flanges on the rollers 4 and 5 also helps in regulating the axial position of the transparent cylinder 2.

As described above, the present invention includes a transparent cylinder rotatably supported around an axis, a radiant heat generating source disposed within the cylinder on the axis, and a radiant heat generating source in close contact with the outer peripheral surface of the cylinder. A conveying device consisting of an endless belt for conveying copy paper, in which two front rollers that press the endless belt against a cylinder are in a fixed position and the interval between them is smaller than the diameter of the cylinder. The belt is wrapped around the cylinder more than half a turn and pressed against the cylinder, and the axis of the rear roller is moved so that it is pressed against the cylinder, making it possible to easily and reliably support the transparent glass cylinder, and to ensure smooth operation. It can be expected that there will be no blurring even at high speed rotation. Therefore, occurrence of image shift and uneven fixing can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an embodiment of the present invention, and FIG.
The figure is a perspective view of the same. FIG. 3 is a side view of an embodiment of the invention with an accessory, and FIG. 4 is a side view of another embodiment. 1...Xenon lamp, 2...Transparent cylinder, 3...
...Endless belt, 4, 5...Roller with immovable shaft, 6, 6', 6''...Roller pressed against pressure, 19...Copy paper.

Claims (1)

[Claims] 1. A transparent cylinder rotatably supported around an axis, a radiant heat generation source disposed within the cylinder on the axis, and an endless belt that conveys copy paper in close contact with the outer peripheral surface of the cylinder. The endless belt is wound more than half a turn around the cylinder, with the two front rollers that press the endless belt against the cylinder in fixed positions and the interval between them being smaller than the diameter of the cylinder. A heat fixing device for a dry type electrophotographic copying machine, which is in pressure contact with a cylinder and is in pressure contact with a cylinder so that the axis of a rear roller can be moved.