JP2970270B2 - Flash fixing method, electrophotographic method and electrophotographic apparatus - Google Patents

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 electrophotographic apparatus of an electrostatic recording system, a developing means develops an electrostatic latent image on a photosensitive means such as a photosensitive drum and a fixing means for transferring the developed toner image onto paper. And a flash fixing type using a flash lamp such as a xenon lamp. In this flash fixing type electrophotographic apparatus, the paper on which the toner image has been transferred is conveyed to a fixing unit by a conveying unit using an endless belt, and the toner absorbs radiant energy at the time of flash lamp emission in the fixing unit and transfers the paper. The melted toner is fused and fixed on paper.

[0003]

In general, in an electrophotographic apparatus, a suction means or the like is provided in the vicinity of the conveying means so as to prevent the sheet conveyed by the conveying means from being lifted and causing a conveyance failure. The paper to be conveyed is adsorbed on an endless belt of a conveying means, or the conveyed paper is electrostatically adsorbed and conveyed by charging the endless belt with a charger.

In the transporting means for transporting the paper conveyed by the suction means to the endless belt as described above, if the housing of the transporting means is made of a conductive material such as a metal, the transported paper may be overlaid. It is necessary to set the housing to the ground level so as not to affect the toner. However, when the paper conveyed by setting the housing of the conveyance means to the ground level is flash-fixed, the toner or resin coating material scattered by the lighting of the lamp during the flash fixing is thermally decomposed. Is electrostatically attached to a lamp of the fixing unit, a cover glass disposed on the front surface of the fixing unit, or the like. As a result, when the electrophotographic apparatus is used for a long period of time, the lamp and the cover glass are stained with toner and the like over time, so that the heat from the flash lamp is shut off and the toner is not transmitted to the paper, resulting in poor toner fixation. There was a problem of doing.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a flash fixing method, an electrophotographic method, and an electrophotographic apparatus capable of avoiding defective toner fixing due to long-term use. .

[0006]

According to the flash fixing method of the present invention, in order to achieve the above object, a method of fixing a toner image on a sheet using flash light while conveying the sheet by a sheet conveying belt. , To the toner image on the paper,
In opposite polarity to the charging polarity of the toner image, and, separate from the sheet conveying belt, the absolute value 100 between ground
The electrostatic suction force is applied from the back surface of the paper using a paper suction means having a bias voltage of 500V. Further, according to the electrophotographic method of the present invention, a latent image forming step of forming an electrostatic latent image on a 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 paper, and a fixing step of fixing the toner image on the paper to the paper by flash light while transporting the paper by a paper transport belt, and In the fixing step, the toner image on the paper has a polarity opposite to the charging polarity of the toner image, and is grounded separately from the paper transport belt.
In this configuration, an electrostatic attraction force is applied from the back surface of the paper using a paper suction means having a bias voltage having an absolute value of 100 to 500 V.

Further, according to the electrophotographic apparatus of the present invention,
A photosensitive medium, latent image forming means for forming an electrostatic latent image on the photosensitive medium, developing means for developing the electrostatic latent image on the photosensitive medium with toner to form a toner image, and toner on the photosensitive medium A transfer unit for transferring an image onto a sheet, a fixing unit for fixing a toner image on the sheet to the sheet by flash light, and a sheet conveyed from the transfer unit to the fixing unit, and the sheet after fixing from the fixing unit. An endless transport belt to be discharged, and a paper suction means disposed in the endless transport belt, and the paper suction means has a polarity opposite to the charging polarity of the toner image on the toner image on the paper, And earth
And a means for applying a bias voltage having an absolute value of 100 to 500 V is connected between them.

Preferably, a plurality of the endless conveyor belts are arranged in a direction orthogonal to the sheet conveying direction, and the paper suction means is provided with an air inlet opening between the plurality of endless conveyor belts. Configuration.

[0009]

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

In this case, in the electrophotographic apparatus, a plurality of the endless conveyor belts are arranged in a direction perpendicular to a sheet conveying direction, and the sheet suction means is opened between the plurality of endless conveyor belts. If the suction holes are provided, the conveyance failure of the conveyed paper is eliminated by the suction of the paper by the paper suction means, and the cleaning life of the fixing means is extended by the electrostatic adsorption of the toner by applying the bias voltage.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a flash fixing method, an electrophotographic method and an electrophotographic apparatus according to the present invention will be described below in detail 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 provided with a brush, a static elimination lamp 7, and a charger 8 around the photosensitive drum 2. These are arranged in a known manner. In the developing section 4, a developer in which carbon is coated with a resin is used.

The electrophotographic apparatus 1 fixes the paper conveyance path R formed in a substantially horizontal direction to the left near the photosensitive drum 2 with respect to the paper conveyance path R indicated by an arrow in the figure and at the upper portion with the paper conveyance path R interposed therebetween. A plurality of transport belts 10 each serving as a paper transport unit are disposed below the container 9. Conveyor belt 1
Reference numeral 0 denotes an endless belt wound between rollers 11a and 12a attached to two rotating shafts 11 and 12, respectively, as shown in FIG. A blower housing 20 is provided. Further, the fixing device 9 and the plurality of transport belts 10 in the transport path R are provided.
Discharge rollers 13 and 14 for discharging the sheet on which the toner image is fixed are disposed downstream of the printer, and the above-described components are compactly disposed in a housing (not shown).

The fixing device 9 develops the electrostatic latent image formed on the photosensitive drum 2 with powder toner in the developing unit 4,
The toner image transferred onto the paper by the charger 5 is thermally fixed. Flash lamps, for example, xenon lamps 9c, 9c are provided in a metal housing 9b having a cover glass 9a attached to the front surface. . Here, the inner surface of the housing 9b is a reflection surface so as to reflect the flash light with a high reflectance.

In this case, as shown in FIG. 3, the fixing device 9 is provided with a trigger electrode E _T along the outer wall of the xenon lamp 9c.
The provided the distance between the arc electrode E _A and the housing 9b xenon lamp 9c G (mm), the distance between the retaining band B which holds the arc electrode E _A and the trigger electrode E _T m (m
m), when the trigger voltage is V (KV), the following relationship is established between them. That is, m ≧ G + 0.3V, G ≧ 0 In normal flash fixing, in order to increase the efficiency of the flash lamp, the flash lamp is brought as close as possible to the housing 9b having the function of a reflector, and the arc electrode indicated by y in the figure is used. it is necessary to shorten the distance from E _a to the fixing capable position of the paper P (the length L). However, since the trigger voltage is usually a voltage of about 10 to 20 KV,
If the flash lamp is brought too close to the housing 9b,
The voltage leaks to the housing 9b. Therefore, in the conventional fixing device, and the arc electrode E _A housing 9
distance G between b is -5 to-10 mm, the distance y from the arc electrode E _A to a position capable of fixing the sheet P was required about 30 mm.

[0015] Therefore, by setting as described above, with closer flash lamp housing 9b and the arc electrode E _A is disposed within the housing 9b, arc electrode E
The distance y from _A to the position where the sheet P can be fixed can be reduced. 17mm example, when the distance G between the arc electrode E _A and the housing 9b and 5 mm, the distance y
And about half.

In the blower housing 20, the toner image is transferred from the photosensitive drum 2 by the charging device 5, and the sheet conveyed to the fixing device 9 by the plurality of conveying belts 10 is sucked. It is to prevent. As shown, the blower housing 20 is a housing disposed in a flat space formed by the plurality of transport belts 10, and a bias voltage is applied by a contact. This bias voltage is set to a polarity opposite to that of the developer, that is, the charge polarity of the toner image transferred onto the sheet by the charger 5. For example, the bias voltage is negative when the toner polarity is positive, and the toner polarity is negative. In the case of, set each of them exactly. The blower housing 20 has a plurality of suction holes 21 formed between the plurality of conveyor belts 10 on the upper surface on the side of the sheet to be conveyed, and a blower 22 for sucking and discharging air in the housing 20 is provided at a lower portion. Have been. Further, as shown in FIG. 2, a paper sensor 23 for detecting the presence or absence of a conveyed paper is provided above the housing 20.
Is provided.

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

The toner image developed on the photosensitive drum 2 is transferred by a transfer charger 5 onto a sheet conveyed on a conveyance path R indicated by an arrow. The sheet on which the toner image has been transferred is sucked by 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 of the toner image onto the paper by the transfer charger 5 is completed, the photosensitive drum 2 is neutralized by turning on the neutralizing lamp 7. After the remaining toner that has not been transferred to the toner is removed by cleaning, the charge is removed by the lit discharge lamp 7 and the next use is performed.

The fixing device 9 fixes the toner image transferred onto the conveyed sheet by a method described below. That is, in the fixing device 9, the housing 2
0, the presence of the sheet on which the toner image has been transferred is detected by the sheet sensor 23 provided in the xenon lamps 9c, 9c.
Is turned on, the unfixed toner image is melted by the generated heat, is fixed on the sheet, 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. For this reason, even if the resin-coated carbon toner is thermally decomposed and scattered by flash fixing by lighting of the xenon lamps 9c, 9c, the scattered toner is applied to the blower housing 20 by the applied reverse polarity bias voltage.
Attracted electrostatically. Therefore, the cover glass 9a is not contaminated by the scattered toner, so that the xenon lamps 9c, 9c do not deteriorate in the transmittance of flash light and heat. Moreover, the fixing device 9
Since the cleaning life is extended, the fixability of the toner image is not impaired even when used for a long time.

[0021] In this electrophotographic apparatus 1, the bias voltage is set to -100-500V, were full rush fixing the toner image by the fixing device 9, the developer that is thermally decomposed with the toner itself and flash fixing No resin component adhered to the cover glass. Here, when the toner image is flash-fixed, the light leaked from the xenon lamps 9c may be positively used for neutralizing the photosensitive drum 2 after transferring the toner image onto the sheet. That is, after the transfer of the toner image onto the sheet by the transfer charger 5, the sheet is conveyed to the position of the fixing device 9, and the xenon lamps 9c start lighting. At this time, after the photosensitive portion of the photosensitive drum 2 irradiated with the leakage light of the xenon lamps 9c, 9c has passed the position of the charge removing lamp 7,
By dimming the light quantity of the static elimination lamp 7 or turning off the static elimination lamp 7, the static elimination light quantity of the photosensitive drum 2 is optimized,
Before and after the xenon lamps 9c, 9c are turned on, the photosensitive drum 2
The change in the potential difference on the surface of the substrate is suppressed.

In this way, as in the electrophotographic apparatus 1 shown in FIG. 1, the paper transport path R can be made substantially flat without curving, and unnecessary bending habits are not formed on the paper to be processed. Can be prevented. Therefore, in particular, there is an advantage that the paper does not have a curl in thick paper or tack paper.
In addition, in the case of tack paper, if the transport path R is curved, the paper may bend at the perforations, causing uneven transport, or preventing the toner image from being transferred onto the paper near the perforations. Although there is a problem that the tack is peeled off, such a problem does not occur because the transport path R is substantially flat.
For this reason, it is possible to continuously obtain an electrophotograph having a 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 can be used for a long time. And an excellent effect that clear electrophotography can be obtained by avoiding poor fixing.

In the electrophotographic apparatus, a plurality of endless conveyor belts are arranged in a direction perpendicular to the sheet conveying direction, and the paper suction means opens between the plurality of endless conveyor belts. Is provided, the conveyance failure of the conveyed paper is eliminated by the suction of the paper by the paper suction means, and the cleaning life of the fixing means can be extended by the electrostatic adsorption of the toner by applying the bias voltage.

[Brief description of the 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 conveyance belt and a paper suction unit.

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

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Electrophotographic apparatus 2 Photosensitive drum 4 Developing part 5 Charging device (for transfer) 7 Static elimination lamp 9 Fixing device 9a Cover glass 9b Housing 9c Xenon lamp 10 Transport 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

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-60-11576 (JP, A) JP-A-57-2072 (JP, A) JP-A-64-32280 (JP, A) JP-A 64-64 19381 (JP, A) JP-A-61-138275 (JP, A) JP-A 62-76365 (JP, U) JP-A 62-99078 (JP, U) (58) Fields investigated (Int. ⁶ , DB name) G03G 13/20 G03G 15/20

Claims (4)

(57) [Claims] When a toner image on a sheet is fixed by using a flash light while the sheet is conveyed by a sheet conveying belt, the toner image on the sheet has a polarity opposite to a charging polarity of the toner image. and, separate from the sheet conveying belt, a
A flash fixing method, wherein an electrostatic attraction force is applied from the back surface of the sheet using a sheet suction means having a bias voltage having an absolute value of 100 to 500 V between the sheet and the sheet. A latent image forming step of forming an electrostatic latent image on the photosensitive medium; 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 image onto the sheet, and a fixing step of fixing the toner image on the sheet to the sheet by flash light while the sheet is conveyed by a sheet conveying belt; and The toner image is formed on a sheet by using a sheet suction unit having a reverse polarity to the charging polarity of the toner image and having a bias voltage having an absolute value of 100 to 500 V between the ground and another sheet conveying belt. An electrophotographic method, wherein an electrostatic attraction force is applied from the back of the device. 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 toner to form a toner image, Transfer means for transferring the toner image on the photosensitive medium onto the sheet, fixing means for fixing the toner image on the sheet to the sheet by flash light, and sheet after conveying and fixing the sheet from the transfer means to the fixing means And an endless transport belt that discharges the toner from the fixing unit, and a paper suction unit disposed in the endless transport belt, and the paper suction unit includes a toner image on a sheet and a charge polarity of the toner image. Are of opposite polarity,
And an electrophotographic apparatus, wherein the absolute value of the means for applying a bias voltage of 100~500V is connected between ground. Wherein said endless conveyor belt is a plurality of arranged in a direction Cartesian to the conveying direction of the sheet, and an opening for air intake hole is provided between the endless conveyor belts of the plurality of the sheet suction unit The electrophotographic apparatus according to claim 3, wherein: