JPH06167905A - Flash fixing method, electrophotographic method and electrophotographic device - Google Patents

Abstract

(57) [Summary] (Corrected) [Objective] To provide a flash fixing method, an electrophotographic method, and an electrophotographic apparatus capable of avoiding toner fixing failure due to long-term use. A photosensitive medium 2, a latent image forming means for forming an electrostatic latent image on the photosensitive medium, a developing means 4 for developing the electrostatic latent image on the photosensitive medium with a toner to form a toner image, and a photosensitive medium. A transfer unit 5 that transfers the toner image on the sheet to the sheet, a fixing unit 9 that fixes the toner image on the sheet to the sheet by flash light, a sheet that is conveyed from the transfer unit to the fixing unit, and the sheet that has been fixed is fixed. It has a plurality of endless conveyor belts 10 discharged from the means, and a paper suction means 20 arranged in these endless conveyor belts, and the paper suction means has a toner image on a sheet and the toner image is charged. A means for applying a bias voltage having a polarity opposite to the polarity is connected, and an electrophotographic method and an electrophotographic apparatus 1 for fixing a toner image on a sheet by applying an electrostatic adsorption force to the toner image from the back surface of the sheet in the fixing step. .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flash fixing method, an electrophotographic method and an electrophotographic apparatus.

[0002]

2. Description of the Related Art In an electrostatic recording type electrophotographic apparatus, as a fixing means for developing an electrostatic latent image on a photosensitive means such as a photosensitive drum by a developing means and transferring the developed toner image onto a sheet. , There is a flash fixing type that uses a flash lamp such as a xenon lamp. In this flash-fixing type electrophotographic apparatus, a sheet on which a toner image has been transferred is conveyed to a fixing unit by a conveying unit that uses an endless belt, and the toner absorbs the radiant energy when the flash lamp emits light and transfers the sheet. The fused toner is melted and fixed on the paper.

[0003]

Generally, in an electrophotographic apparatus, a suction means or the like is provided in the vicinity of the conveying means so that the sheet conveyed by the conveying means does not float and a conveyance failure occurs. The sheet to be conveyed is adsorbed on the endless belt of the conveying means, or the sheet to be conveyed is electrostatically adsorbed and conveyed by charging the endless belt with a charger.

In the conveying means for conveying the sheet conveyed by the suction means while sucking it onto the endless belt, when the housing of the conveying means is made of a conductive material such as metal, the sheet to be conveyed is It is necessary to set the housing to the ground level so that it does not affect the toner of. However, when the sheet of the conveyed sheet is fixed by flash fixing with the housing of the conveying means set to the ground level in this way, the toner or the resin coating material scattered by the lighting of the lamp may be thermally decomposed during the flash fixing. , Electrostatically adheres to a lamp of the fixing unit, a cover glass arranged in front of the fixing unit, or the like. For this reason, when the electrophotographic apparatus is used for a long period of time, the lamp or the cover glass is contaminated with toner or the like over time, resulting in the heat from the flash lamp being cut off and not being transferred onto the paper, resulting in toner fixing failure. There was a problem of doing.

The present invention has been made in view of the above points, and an object thereof is to provide a flash fixing method, an electrophotographic method, and an electrophotographic apparatus capable of avoiding toner fixing failure due to long-term use. .

[0006]

According to the flash fixing method of the present invention, in order to achieve the above object, when a toner image on a sheet is fixed using flash light, the toner image is fixed on the sheet from the back side of the sheet. The configuration is such that electroadhesive force is applied. According to the electrophotographic method of the present invention, a latent image forming step of forming an electrostatic latent image on the photosensitive medium, and a developing step of developing the electrostatic latent image on the photosensitive medium with a toner to form a toner image. A transfer step of transferring the toner image on the photosensitive medium onto a sheet of paper, and a fixing step of fixing the toner image on the sheet of paper by flash light to the sheet of paper. It is configured such that an electrostatic attraction force is applied thereto.

Further, according to the electrophotographic apparatus of the present invention,
A photosensitive medium, a latent image forming means for forming an electrostatic latent image on the photosensitive medium, a developing means for developing the electrostatic latent image on the photosensitive medium with a toner to form a toner image, and a toner on the photosensitive medium. Transfer means for transferring the image onto the paper, fixing means for fixing the toner image on the paper to the paper by flash light, conveying the paper from the transfer means to the fixing means, and fixing the paper from the fixing means. It has a plurality of endless conveyor belts for discharging and paper suction means arranged in these endless conveyor belts, and the paper suction means has a toner image on the paper and a charge polarity of the toner image. The configuration is such that means for applying a bias voltage of reverse polarity is connected.

[0008] Preferably, a plurality of the endless conveyor belts are arranged in a direction orthogonal to a sheet conveying direction, and the sheet suction means is provided with an air intake hole opened between the plurality of endless conveyor belts. The configuration is

[0009]

In the flash fixing method, the electrophotographic method and the electrophotographic apparatus of the present invention, the toner image transferred on the paper is reversely charged to the paper suction means when the flash image is fixed by the fixing means. A bias voltage of polarity is applied. Therefore, even if the toner or the resin coating material is thermally decomposed and scattered by flash fixing, it is electrostatically attracted to the sheet suction means side and does not adhere to the fixing means.

At this time, in the electrophotographic apparatus, a plurality of the endless conveyor belts are arranged in a direction orthogonal to the sheet conveying direction, and the sheet suction means is opened between the plurality of endless conveyor belts. The provision of the intake holes eliminates the conveyance failure of the conveyed sheet due to the suction of the sheet by the sheet suction unit, and extends the cleaning life of the fixing unit due to the electrostatic attraction of the toner due to the application of the bias voltage.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a flash fixing method, an electrophotographic method and an electrophotographic apparatus of the present invention will be described in detail below with reference to FIGS. The electrophotographic apparatus 1 includes a light source 3, a developing unit 4 using powder toner, a transfer / separation charger 5, a cleaning unit 6 including a brush, a charge eliminating lamp 7 and a charger 8 around the photosensitive drum 2. Known materials are used for these, and in the developing unit 4, a developer having a carbon surface coated with a resin is used.

Then, the electrophotographic apparatus 1 is fixed to the upper part of the sheet conveyance path R, which is formed in a substantially horizontal direction, on the left side in the vicinity of the photosensitive drum 2 with respect to the sheet conveyance path R indicated by an arrow in FIG. The container 9 is provided with a plurality of conveyor belts 10 serving as paper conveying means at the bottom thereof. Conveyor belt 1
As shown in FIG. 2, 0 is an endless belt wound between rollers 11a and 12a attached to two rotating shafts 11 and 12, respectively. A blower housing 20 is provided. In addition, the fixing device 9 on the transport path R and the plurality of transport belts 10
Discharging rollers 13 and 14 for discharging the sheet on which the toner image has been fixed are arranged on the downstream side of the above, and the above-mentioned components are compactly arranged in a housing (not shown).

In the fixing device 9, the electrostatic latent image formed on the photosensitive drum 2 is developed with powder toner in the developing section 4,
The toner image transferred onto the sheet by the charger 5 is heat-fixed, and flash lamps such as xenon lamps 9c and 9c are provided in a metal housing 9b having a cover glass 9a mounted on the front surface. . Here, the inner surface of the housing 9b is a reflective surface so as to reflect the flash light with high reflectance.

In this case, as shown in FIG. 3, the fixing device 9 includes the trigger electrode E _T along the outer wall of the xenon lamp 9c.
The distance between the arc electrode E _A of the xenon lamp 9c and the housing 9b is G (mm), and the distance between the arc electrode E _A and the holding band B holding the trigger electrode E _T is m (m
m) and when the trigger voltage is V (KV), the following relations are established between them. That is, m ≧ G + 0.3V, G ≧ 0 In normal flash fixing, in order to improve the efficiency of the flash lamp, the flash lamp is brought as close as possible to the housing 9b having the function of a reflection plate, and the arc electrode shown by y in the drawing is used. It is necessary to shorten the distance from E _A to the position where the sheet P (length L) can be fixed. However, since the trigger voltage is usually about 10 to 20 KV,
If the flash lamp is too close to the housing 9b,
The voltage leaks to the housing 9b. Therefore, in the conventional fixing device, the arc electrode E _A and the housing 9
The distance G from b was -5 to -10 mm, and the distance y from the arc electrode E _A to the position where the paper P could be fixed was about 30 mm.

For this reason, when set as described above, the arc electrode E _A is arranged in the housing 9b to bring the flash lamp closer to the housing 9b, and at the same time, the arc electrode E _A is set.
The distance y from _A to a position where the sheet P can be fixed can be reduced. For example, if the distance G between the arc electrode E _A and the housing 9b is 5 mm, the distance y is 17 mm.
And can be about half.

In the blower housing 20, the toner image is transferred from the photosensitive drum 2 by the charging device 5, and the paper conveyed to the fixing device 9 is sucked by the plurality of conveying belts 10 and the conveyance failure of the paper occurs due to the lifting during the conveyance. Is to prevent. As shown in the drawing, the blower housing 20 is a housing arranged in a flat space formed by a plurality of conveyor belts 10, and a bias voltage is applied by a contactor. This bias voltage is set to a polarity opposite to the charge polarity of the developer, that is, the toner image transferred on the sheet by the charger 5, and is negative when the toner polarity is positive and negative when the toner polarity is negative. In the case of, set them to be positive. Further, the blower housing 20 has a plurality of suction holes 21 formed between the plurality of conveyance belts 10 formed on the upper surface of the conveyed sheet, and a blower 22 for sucking and discharging the air in the housing 20 is provided in the lower portion. Has been. Further, as shown in FIG. 2, a paper sensor 23 for detecting the presence or absence of paper being conveyed is provided on the upper portion of the housing 20.
Is provided.

In the electrophotographic apparatus 1 configured as described above, first, the photosensitive drum 2 rotating at a constant speed in the direction of the arrow is uniformly charged by the charger 8, and then the light beam having the recorded information is recorded. Is emitted from the light source 3. By this irradiation of the light beam, an electrostatic latent image corresponding to the recorded information is formed on the photosensitive drum 2, and the electrostatic latent image is developed by the powder toner in the developing unit 4 by the rotation of the photosensitive drum 2 and the toner. It becomes an image (visible image).

Then, the toner image developed on the photosensitive drum 2 is transferred by the transfer charger 5 onto the sheet conveyed on the conveying path R indicated by the arrow. The sheet on which the toner image is transferred is attracted to the blower housing 20 and is conveyed to the fixing device 9 through the conveyance path R by the plurality of conveyance belts 10. At this time, when the transfer charger 5 finishes transferring the toner image onto the paper, the charge removal lamp 7 of the photosensitive drum 2 is turned on and the charge is removed. After the remaining toner that has not been transferred to the toner is removed by cleaning, the electricity is removed by the electricity removing lamp 7 that is turned on, and the toner is provided for the next use.

The fixing device 9 fixes the toner image transferred on the conveyed sheet by the method described below. That is, in the fixing device 9, the housing 2
When the presence of the paper on which the toner image is transferred is detected by the paper sensor 23 provided at 0, the xenon lamps 9c, 9c
Lights up, the unfixed toner image is melted by the generated heat and fixed on the paper, and is discharged by the discharge rollers 13 and 14.

At this time, in the flash fixing method of the present invention, a bias voltage having a polarity opposite to the charging polarity of the toner image is applied to the blower housing 20. Therefore, even if the resin-coated carbon toner is thermally decomposed and scattered by flash fixing by lighting the xenon lamps 9c and 9c, the scattered toner is blown by the applied bias voltage of the reverse polarity to the blower housing 20.
Be electrostatically attracted to. Therefore, since the scattered toner does not adhere to the cover glass 9a to be contaminated, the permeability of the flash light and heat of the xenon lamps 9c and 9c does not decrease. Moreover, the fixing device 9
Since the cleaning life is extended, the fixing property of the toner image is not impaired even if it is used for a long time.

In this electrophotographic apparatus 1, when the bias voltage was set to -100 V to -500 V and the toner image was flash-fixed by the fixing device 9, the toner itself and the resin of the developer thermally decomposed with the flash fixing. Neither component adhered to the cover glass. Here, in the flash fixing of the toner image described above, the leaked light from the xenon lamps 9c, 9c may be positively used for static elimination of the photosensitive drum 2 after the toner image is transferred onto the paper. That is, after the toner image is transferred onto the paper by the transfer charger 5, the paper is conveyed to the position of the fixing device 9 and the xenon lamps 9c and 9c start lighting. At this time, after the photosensitive portion of the photosensitive drum 2 irradiated with the leaked light from the xenon lamps 9c and 9c has passed the position of the static elimination lamp 7,
By reducing the light quantity of the charge eliminating lamp 7 or turning off the charge eliminating lamp 7, the charge eliminating light quantity of the photosensitive drum 2 is optimized,
The photosensitive drum 2 before and after the xenon lamps 9c and 9c are turned on.
The change in the potential difference on the surface of the is suppressed.

By doing so, the sheet conveying path R can be made substantially flat without curving, as in the electrophotographic apparatus 1 shown in FIG. 1, so that the sheet to be processed has an unnecessary bending tendency. It can be prevented. Therefore, there is an advantage that the paper does not have a bending tendency particularly in thick paper and tack paper.
Moreover, in the case of tack paper, if the conveyance path R is curved, the paper is bent at the perforations, causing uneven conveyance, or the toner image cannot be transferred onto the paper near the perforations. Although there is a problem that the tack is peeled off, this problem does not occur because the transport path R is substantially flat.
Therefore, it is possible to continuously obtain electrophotographic images having uniform image quality.

[0023]

As is apparent from the above description, according to the flash fixing method, the electrophotographic method, and the electrophotographic apparatus of the present invention, when a toner image is fixed on a sheet by flash fixing, the toner is used for a long time. There is an excellent effect that it is possible to obtain a clear electrophotographic image by avoiding the fixing failure of (1).

Further, in the electrophotographic apparatus, a plurality of endless conveyor belts are arranged in a direction orthogonal to the sheet conveying direction, and the sheet suction means is provided with an intake hole opened between the plurality of endless conveyor belts. When the sheet is provided, the conveyance failure of the conveyed sheet is eliminated by the suction of the sheet by the sheet suction unit, and the electrostatic attraction of the toner by the application of the bias voltage can extend the cleaning life of the fixing unit.

[Brief description of drawings]

FIG. 1 illustrates a flash fixing method, an electrophotographic method, and an electrophotographic apparatus of the present invention, and is a schematic configuration diagram of an electrophotographic apparatus to which the flash fixing method of the present invention is applied.

FIG. 2 is a plan view showing an arrangement of an endless conveyor belt and a sheet suction unit.

FIG. 3 is a detailed view showing the arrangement of trigger electrodes and the like in the fixing unit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Electrophotographic device 2 Photosensitive drum 4 Development part 5 Charger (for transfer) 7 Electrification lamp 9 Fixing device 9a Cover glass 9b Housing 9c Xenon lamp 10 Conveyor belt 20 Blower housing (paper suction means) 21 Suction hole 22 Blower 23 Paper sensor B Holding band E _A Arc electrode E _T Trigger electrode P Paper

Claims (4)

[Claims] 1. A flash fixing method characterized in that, when a toner image on a sheet is fixed using flash light, an electrostatic adsorption force is applied to the toner image from the back side of the sheet. 2. A latent image forming step of forming an electrostatic latent image on a photosensitive medium, a developing step of developing the electrostatic latent image on the photosensitive medium with a toner to form a toner image, and a toner on the photosensitive medium. It has a transfer process of transferring the image onto the paper and a fixing process of fixing the toner image on the paper to the paper by flash light.
In addition, in the fixing step, an electrostatic attraction force is applied to the toner image from the back surface of the sheet, which is an electrophotographic method. 3. A photosensitive medium, a latent image forming means for forming an electrostatic latent image on the photosensitive medium, a developing means for developing the electrostatic latent image on the photosensitive medium with a toner to form a toner image, Transfer means for transferring the toner image on the photosensitive medium onto the paper, fixing means for fixing the toner image on the paper to the paper by flash light, and paper for transporting the paper from the transfer means to the fixing means and fixing the paper. A plurality of endless conveyor belts for discharging the sheet from the fixing means, and a paper suction means arranged in these endless conveyor belts. An electrophotographic apparatus, to which a means for applying a bias voltage having a polarity opposite to the charging polarity of is connected. 4. A plurality of the endless conveyor belts are arranged in a direction orthogonal to a sheet conveying direction, and the sheet suction means is provided with an intake hole that opens between the plurality of endless conveyor belts. The electrophotographic apparatus according to claim 3, wherein