JPS638471B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a device for performing heat fixing using a flash lamp in a dry electrostatic copying machine.

(Prior art) Conventionally, as shown in Japanese Unexamined Patent Publication No. 49-50946, image-receiving paper is electrostatically attracted to a strip, and when the edge of the portion of the image-receiving paper to be transferred passes over a roller, There is a known toner welding device in which the image receiving paper is bent into a cylindrical shape around the longitudinal axis of a radiant heat energy source, but the inner surface of the image receiving paper is basically in contact with the roller only at its edges. type,
The image may become smudged due to toner scattering from the flash lamp, or areas of the receiving paper where electrostatic adhesion is insufficient may fall to the flash side, resulting in uneven fixation.
There was a problem that the image receiving paper would burn due to the explosion of the flash lamp, leading to a fire.

(Purpose) The present invention prevents uneven fixing by keeping the copy paper completely adhered to the fixing drum and not floating when instantaneously heating and fixing with a flash lamp, and prevents toner from scattering and smearing the image. The purpose is to prevent copy paper from causing a fire.

(Structure) In order to achieve the above object, the present invention includes a transparent cylinder rotatably supported around an axis, a flash lamp arranged on the axis within the cylinder, and an outer circumferential surface of the cylinder. The cylinder is driven by the conveyor belt or driven at the same speed as the conveyor belt, and the copy paper is inserted between the cylinder and the conveyor belt and they rotate together. It is characterized in that it heats and fixes by emitting light from a lamp.

Hereinafter, a detailed explanation will be given based on the illustrated embodiment. 1 is a photoreceptor drum, which develops an electrostatic latent image formed on its surface by adsorbing toner 4;
This is transferred onto copy paper 3 by a transfer device 2. 5 is an endless belt, which may be either transparent or opaque, and may be made of Mylar, Teflon resin belt, glass fiber, or carbon fiber impregnated or coated with resin, rubber, etc., and the width may be the entire width or several strips. It may also be divided. Furthermore, since the deviation of the belt is the most problematic, it is preferable to provide a well-known belt deviation prevention device to prevent deviation, or to provide a perforated belt and a sprocket to prevent deviation. It is driven by a pulley 6 rotating in the direction of arrow A, and the copy paper 3 peeled off from the photosensitive drum 1 is conveyed as shown by arrow B by a peeling claw 7. A photoelectric element 8 faces the light source 9 across the conveyance path, and photoelectrically detects passage of the copy paper 3.

Reference numeral 10 denotes a transparent cylinder made of glass or plastic, which is rotatably supported on a central axis.The roller 11c on the entrance side and the roller 11a on the exit side are slightly apart from the cylinder 10, and the intermediate roller 1
Only the cylinder 1b is in contact with the cylinder 10, and a rod-shaped flash lamp 12, for example, a xenon lamp 12, is arranged on the axis of rotation of the cylinder 10. The xenon lamp 12 is energized by the circuit shown in FIG. 13 is an endless belt wound around the cylinder 10, and the rollers 11a, 11b, 11
C and guide rollers 14a to 14d, a constant tension is applied to the cylinder 10, and the cylinder 10 is wound more than half a turn around the outer circumference of the cylinder 10, and is driven to run in the direction of arrow C. The roller 11c is connected to the endless belt 5.
It is placed on an extension of the conveyance path.

Reference numeral 15 is a peeling claw that is brought into sliding contact with the cylinder 10, and the copy paper 3 that has been conveyed is pressed against the circumferential surface of the cylinder 10 by the endless belt 13.
is peeled off from the cylinder 10, and it is attached to the feed roller 1.
6a, 16b. The feed rollers 16a and 16b are urged to press against each other,
They are rotationally driven in the directions of arrows D and E, respectively.
Reference numeral 17 denotes a coating roller that is pressed against the circumferential surface of the cylinder 10, and rotates in the direction of arrow F due to friction with the cylinder 10. The application roller 17 includes a supply roller 1.
8 is in rolling contact with the supply roller 18, and a push plate 21 on which a felt 19 is urged by a spring 20 is attached to the supply roller 18.
It is pressed by. The lower end of the felt 19 is immersed in oil 23 filled in an oil pan 22. This oil 23 is used to form an offset prevention layer on the circumferential surface of the cylinder 10, and silicone oil, fluorine oil, animal oil, vegetable oil, wax, etc. can be used. 24 is the endless belt 1 at the position of the guide roller 14c.
The blade 25 is in sliding contact with the endless belt 13 and is for cleaning the oil 23 adhering to the endless belt 13. A blade 25 is also in sliding contact with the endless belt 13 for the same purpose.

Next, the operation of the device will be explained.

The copy paper 3, which has been transferred from the photosensitive drum 1, is conveyed with the copy side upward by the endless belt 5 in the direction of arrow B, and is conveyed between the cylinder 10 rotating in the direction of arrow G and the endless belt 13. inserted into. Copy paper 3 is endless belt 13
As a result, it comes into close contact with the circumferential surface of the cylinder 10, and is conveyed in the direction of arrow G while being integrated with the cylinder 10.
When the passage of the trailing edge of the copy paper 3 is detected by the photoelectric element 8, the xenon lamp 12 emits light for a short time at an appropriate timing. FIG. 7 shows a typical example of a light emitting circuit for a flash lamp. As shown in the figure, the charge stored in the capacitor is triggered to emit light. Generally, the time is about 1/10 to 1/10000 seconds, but it is better to change the circuit or use a normal power source to emit light for a short time of less than 1 second. At this time, since the entire surface of the copy paper 3 is brought into close contact with the circumferential surface of the cylinder 10, radiant heat from the xenon lamp 12 is simultaneously applied to the entire surface of the copy paper 3 via the transparent cylinder 10. Therefore, this radiant heat melts the toner 4 on the copy paper 3 and fixes it. The copy paper 3 that has been fixed is removed from the cylinder 10 by the action of the peeling claw 15.
is peeled off from the peripheral surface of the feed rollers 16a, 16.
b, it is discharged as shown by arrow H.

As the cylinder 10 rotates in the direction of arrow G, the application roller 17 rotates in the direction of arrow F, and the supply roller 1
8 also rotates in the direction of arrow J. Since the felt 19 sucks up the oil 23 by capillary action, the oil 23 is applied to the circumferential surface of the supply roller 18.
Since it adheres to the circumferential surface of the application roller 17 and is further applied to the circumferential surface of the cylinder 10, this oil film forms an offset prevention layer and prevents the molten toner 4 from adhering to the circumferential surface of the cylinder 10. To prevent. If an excessive amount of oil 23 is supplied, it will stain the copy paper 3, so the supply amount must be adjusted to an appropriate amount, and this is done by the supply roller 18 and felt 19. In other words, since the supply roller 18 is in a braking state due to the pressure of the felt 19, it rotates when the frictional force between it and the applicator roller 17 is greater than the braking force, but when it is small, it rotates. It does not rotate. When enough oil 23 is supplied to the circumferential surface of the application roller 17, the frictional force between it and the supply roller 18 becomes small and the supply roller 18 stops, so no more oil 23 is supplied. Not possible. When the amount of oil 23 on the circumferential surface of the application roller 17 decreases, the rotation of the supply roller 18 is restarted, so that the oil 23 is supplied to the application roller 17 again. In this way, an appropriate amount of oil 23 is always supplied to the application roller 17.

Good results were obtained by using a glass tube with a diameter of 200 mm and a length of 300 mm as the cylinder 10, and by causing the xenon lamp 12 to emit light for 1/1000 seconds. In addition, the glass tube is coated with Teflon, and as oil 23, silicone oil 10~
When 300CS was applied and a toner with a low melting point was used, no offset occurred even at a conveyance speed of 500 mm/sec.

The thickness of the Teflon layer is 1μ or more, preferably 10μ or more, as long as it allows the radiant heat of the xenon lamp to pass through this layer.

By providing the cylinder 10 with an offset prevention layer made of Teflon, silicone rubber, etc., it is not necessarily necessary to apply oil. This is because the temperature of the cylinder 10 does not become as high as that of a heating roller. Naturally, oil can also be used in combination with the Teflon and silicone rubber layers.

The support structure for the cylinder 10 includes rollers 11a to 11c in contact with its outer circumferential surface, as well as support rollers 26a to 26 in contact with its inner surface as shown in FIG.
It may also be done by d.

In addition, as shown in FIG. 3, elastic rings (for example, heat-resistant rubber or plastic may be used to absorb the difference in thermal expansion between the glass tube and the shaft) 27 are attached to both ends of the cylinder 10. Through the shaft fitting 2
8 may be fitted and fixed and supported by a bearing (not shown). In this case, the xenon lamp 12 may be rotated together with the cylinder 10, but if the shaft fitting 28 is formed into a cylinder shape as shown in the figure and the non-light emitting part of the xenon lamp 12 is passed through it, the xenon lamp 12 can be rotated together with the cylinder 10. There is no need to rotate the terminal, making it easier to connect the terminal.

The oil 23 may be applied directly to the cylinder 10 using a felt 29 as shown in FIG. In this case, it is necessary to bring the blade 30 into sliding contact with the cylinder 10 to scrape off excess oil. Alternatively, as shown in FIG. 5, the feed roller 18 may be omitted and the felt 19 may be directly pressed against the application roller 17.

The peeling claw 15 that comes into sliding contact with the cylinder 10 also has the function of removing oil 23 and dirt from the circumferential surface of the cylinder 10, as shown in FIG.
It may be collected at However, since the oil adheres to the upper surface of the peeling claw 15, there is a risk that the copy paper 3 may be soiled. This can be prevented by the configuration shown in FIG. That is, peeling nail 1
The tip of the blade 5' is serrated as shown in the figure, and a blade 31 with a straight tip is superimposed on the lower side. Since the peeling claw 15' peels only the copy paper 3 from the cylinder 10 and does not scrape off the oil 23, the upper surface thereof is not stained with the oil 23. The oil 23 and dirt are scraped off by the blade 31 and collected in the oil pan 22. Uniform heating of the back belt (for example, with a general infrared lamp) preheats the paper and further improves fixing properties, so it can also be used as a preheating means. At this time, there is no need to insert a heater (not shown) into the support rolls of the belt and glass tube.

(Effects) The present invention includes a transparent cylinder rotatably supported around an axis, a flash lamp arranged on the axis within the cylinder, and a conveyor wound around more than half of the outer circumferential surface of the cylinder. The cylinder is driven by the conveyor belt or driven at the same speed as the conveyor belt. Copy paper is inserted between the cylinder and the conveyor belt and they rotate together. During this time, a flash lamp is emitted to perform heat fixing. Therefore, when the copy paper is instantaneously heated and fixed using a flash lamp, the copy paper is completely adhered to the fixing drum so that it does not float, preventing uneven fixing, and also preventing the toner from scattering and smearing the image. This has the effect of preventing the copy paper from causing a fire.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of the present invention, FIGS. 2A and B are a front view and a side sectional view of a main part showing a modification of the cylindrical support structure, and FIG. 3 is a front view showing a modification of the cylindrical support structure. FIGS. 4 and 5 are front views showing two modifications of the oil applicator; FIGS. 6A and B are front views and perspective views showing modifications of the peeling claw; FIG. It is a lighting circuit diagram. 3... Copy paper, 10... Transparent cylinder, 12
...Xenon lamp, 13... Endless belt.

Claims (1)

[Claims] 1. A transparent cylinder rotatably supported around an axis, a flash lamp disposed within the cylinder on the axis, and a conveyor belt wound around more than half of the outer circumferential surface of the cylinder, The cylinder is driven by the conveyor belt or driven at the same speed as the conveyor belt, and the copy paper is inserted between the cylinder and the conveyor belt and they rotate together, during which time a flash lamp is emitted to perform heat fixing. Heat fixing device for electrostatic copying machines.