KR20030037326A - Dry unit apparatus of liquid electrophotographic printer - Google Patents

Abstract

PURPOSE: A drying apparatus for a wet electrophotographic printer is provided to prevent an image defect and increase a quality of an image by drying instantly a liquid carrier attached on a photo sensitive belt using a non-contact method. CONSTITUTION: A drying apparatus(260) of a photo sensitive belt includes a heating device(261) which emits a radiant heat for evaporating a liquid carrier coated on the photo sensitive belt(110), a reflecting plate(263) which reflects the radiant heat to the photo sensitive belt, and a manifold(265) which covers the reflecting plate and the heating device to temporarily accommodate gas carrier evaporated by heat from the heating device. The heating device is installed parallel with a width of the photo sensitive belt to not be contacted with the photo sensitive belt. The heat generated from the heating device is irradiated to the photo sensitive belt, and evaporated in the liquid carrier.

Description

Drying apparatus of a wet electrophotographic printer

The present invention relates to a wet electrophotographic printer, and more particularly, to a photosensitive belt drying apparatus for drying a toner image developed on a photosensitive medium.

In general, an electrophotographic printer forms a latent electrostatic image on a photosensitive medium such as a photosensitive drum or a photosensitive belt, develops the electrostatic latent image with a toner of a predetermined color, and transfers the image onto a recording sheet to obtain a desired image. It is an image forming apparatus. The electrophotographic printer is classified into dry and wet according to the toner used. In the dry electrophotographic printer, powder toner is used. On the other hand, in the case of a wet electrophotographic printer, a liquid developer in which a toner is mixed with a volatile liquid carrier is used, and print quality is better than that of a dry type, and at the same time, it is possible to prevent damage caused by harmful toner dust. This is an increasing trend.

1 is a view schematically showing the overall configuration of a conventional wet electrophotographic color printer.

Referring to FIG. 1, the wet electrophotographic color printer 100 is supported by a transfer backup roller 121, a steering roller 122, and a driving roller 123 in the form of a closed curve to allow circulation driving in an endless track. The photosensitive belt 110 provided is provided as a photosensitive medium.

Below the photosensitive belt 110, a laser scanning unit (LSU; Laser scanning unit, 130) for irradiating a laser beam to the photosensitive belt 110 according to an image signal to form an electrostatic latent image by exposure, and the photosensitive belt A developing device 140 is provided for developing an electrostatic latent image by attaching a developer containing a toner of a specific color to the electrostatic latent image formed at 110. The laser scanning unit 130 and the developing device 140 are provided in plural to enable the development of an electrostatic latent image for each color, as shown for color printing.

The photosensitive belt 110 travels in the direction indicated by arrow A with a constant voltage by electric charges applied from the charging device 150. At this time, the laser scanning unit 130 scans the laser beam corresponding to the pattern portion of a specific color to the photosensitive belt 110, and thus the portion that receives the light of the photosensitive belt 110 loses charge. There will be a voltage difference with the unlighted part.

The developing device 140 develops a developer of a specific color on a portion where the charge of the photosensitive belt 110 is lost. The toner image attached to the electrostatic latent image of the photosensitive belt 110 by the developing device 140 is transferred to a transfer roller 124 installed in parallel with the transfer backup roller 121 with the photosensitive belt 110 therebetween. Then, it is transferred to the recording paper 126 supplied between the transfer roller 124 and the fixing roller 125 installed in parallel with it, so that a desired image can be printed.

By the way, the developing solution for developing the electrostatic latent image is a mixture of a solid toner and a liquid carrier, the toner has a color actually printed on the recording paper, the carrier serves as a solvent for transporting the toner. Since the carrier is dried and evaporated by the drying apparatus 160 before printing to be removed from the transfer surface of the photosensitive belt 110, the toner image of the photosensitive belt 110 passes through the drying apparatus 160 and has a liquid component. This is removed and left in a dried state suitable for printing.

The drying device 160 is installed to rotate in contact with a portion of the transfer surface of the photosensitive belt 110 and has a dry roller 161 having a heat source 162 for generating heat on the rotation center axis, and the dry roller And a pair of regeneration rollers 163 installed on the rotational central axis to heat the 161, and having a heat source 164 for generating heat, such as a heat lamp, to rotate in engagement with the dry roller 161. And a dry roller 161 and the regeneration roller 163 and a manifold 165 surrounding them. The manifold 165 may be selectively installed.

The dry roller 161 has a high temperature by the heat source 162 installed on the central axis of rotation, and the surface of the dry roller 161 is made of a material capable of absorbing the liquid carrier. In addition, the contact with the photosensitive belt 110. The regeneration roller 163 is in contact with the dry roller 161.

In the drying apparatus 160 having the above-described configuration, the dry roller 161 is rotated in contact with the photosensitive belt 110 to rotate a liquid carrier in the image ink attached to the transfer surface of the photosensitive belt 110. Compressed and buried, and some of the liquid carrier is evaporated from the surface of the dry roller 161.

The regeneration roller 163 dries the liquid carrier absorbed by the dry roller 161 in a state where it is heated to a constant temperature by the heat source 164 to evaporate it. Evaporated carriers are collected by the manifold 165.

However, since the photosensitive belt drying device 100 absorbs the liquid carrier by evaporating the liquid carrier from the contact surface between the dry roller 161 and the photosensitive belt 110, it is difficult to absorb a sufficient amount of the liquid carrier because of the short contact time. The remaining liquid carrier is not absorbed by the rollers of the transfer apparatus, so that an uneven deformation of the transfer roller occurs, which causes problems such as folding of the printing paper, thereby making it impossible to proceed with printing.

In addition, due to the insufficient drying of the image on the photosensitive belt 110 during the continuous printing, an image defect phenomenon that does not transfer the image when transferring the image to the printing paper occurs.

In addition, since the conventional drying apparatus is a contact method, the image of the surface of the photosensitive belt is picked and remains on the surface of the dry roller or the regeneration roller, thereby affecting the function of the roller. Image picking of the surface becomes a problem of degrading the printed image quality.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and the problem of image defects does not occur by drying the liquid carrier attached to the photosensitive belt using a non-contact type, and the photosensitive belt of the wet electrophotographic printer capable of instantaneously drying the liquid carrier. It is an object to provide a drying apparatus.

1 is a view schematically showing the overall configuration of a conventional wet electrophotographic color printer;

2 is a view showing a schematic configuration of a wet electrophotographic printer having a photosensitive belt drying apparatus according to the present invention;

3 is a view showing the operation of the photosensitive belt drying apparatus 260 according to the present invention.

<Description of the symbols for the main parts of the drawings>

121 ... Transfer backup roller 122 ... Steering roller

123 Driving roller 124 Transfer roller

125 ... station roller 126 ... record sheet

130 ... laser scanning unit 140 ... developing unit

260 ... Photosensitive belt drying unit261 ... Heating means

263 ... Reflector265 ... Manifold

In order to achieve the above object, the photosensitive belt drying apparatus of the wet electrophotographic printer of the present invention is installed so as not to contact the photosensitive belt, and at least one heating means for generating heat for drying and evaporating the liquid carrier on the photosensitive belt; ; Reflection means installed adjacent to the heating means to reflect heat generated from the heating means toward the photosensitive belt in order to improve thermal efficiency; A manifold surrounding the heating means and the photosensitive belt and collecting gas carriers evaporated by the heating means; It is characterized by including.

According to the invention, the heating means is characterized in that the near infrared heater.

According to the present invention, the near infrared heater is characterized in that the wavelength is 1.3㎛.

According to the present invention, the reflecting means is installed adjacent to the heating means so that heat emitted in the opposite direction with respect to the photosensitive belt is horizontally incident on the photosensitive belt.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a view showing a schematic configuration of a wet electrophotographic printer having a photosensitive belt drying apparatus according to the present invention. Here, the same reference numerals as the reference numerals shown in FIG. 1 denote the same components.

2, the photosensitive belt drying apparatus 260 according to the present invention is a heating means 261 for generating a radiant heat for evaporating the liquid carrier buried on the surface of the photosensitive belt 110, and the heating means ( Reflecting plate 263 for reflecting the radiant heat generated by the 261 to the photosensitive belt 110, the reflecting plate 263 and the heating means 261 is wrapped around the evaporation by the heat generated by the heating means 261 It includes a manifold 265 which is a space for temporarily receiving the gas carrier.

In addition, the manifold 265 may be connected to a carrier recovery device (not shown) to recover the gas carriers accommodated in the manifold 265. Such a carrier recovery device uses a general one applied to a conventional wet electrophotographic printer.

The heating means 261 is installed in parallel along the width (not shown) of the photosensitive belt 110 so as not to be in direct contact with the photosensitive belt 110. Heat generated from the heating means 261 is irradiated to the photosensitive belt 110 to evaporate the liquid carrier buried therein.

On the other hand, at least one heating means 261 may be installed with respect to the photosensitive belt 110. This has the advantage that the heat generated from the heating means 261 increases the area irradiated to the photosensitive belt 110, thereby increasing the amount of vaporization of the liquid carrier buried in the photosensitive belt 110. .

The heating means 261 preferably uses a heater that generates near infrared ray. Near infrared ray is characterized by having a stronger heat action than visible light or ultraviolet light, which is why it is also called a hot ray. In particular, the wavelength of the near-infrared ray is consistent with the natural frequency of the polymer material, so that the radiation energy is easily absorbed by the acceleration of molecular motion due to resonance phenomenon, thereby shortening the heating and drying time, and uniformly heating the inside and the outside of the heating target body There is a characteristic that the quality is improved.

Near infrared rays refer to those having a wavelength in the range of 0.75 μm to 3 μm. In contrast, far infrared rays commonly used in electric heaters are long wavelengths having a wavelength of 5 μm. In addition, although the wavelength generation temperature of far infrared rays is 400-500 degree | times. The wavelength generation temperature of near infrared rays is 1800-2200 degrees. Far infrared heat transfer method has the disadvantage that the heat loss is large because it uses convective heat to transfer the air by heating. Near-infrared heat transfer uses radiant heat, so the generated heat is directly heated only by the heating target and can reach the maximum temperature instantaneously. In an embodiment of the present invention, it is preferable to use a near infrared ray having a size of 1.3 μm.

Table 1 below shows the results of measuring the distance (L) and the temperature according to the time between the heating means 261 and the photosensitive belt 110. In Table 1, it can be seen that the distance between the heating means 261 and the photosensitive belt 110 reaches 185.5 degrees after 10 seconds at 50 mm. On the other hand, when using a far-infrared heater in the same conditions, it takes about 3 minutes.

Therefore, when the liquid carrier buried in the photosensitive belt 110 is evaporated using a near infrared heater, the target temperature required for evaporating the liquid carrier may be reached within a short time. Therefore, it can be seen that using the near infrared ray in the heating means 261 is superior to using the far infrared ray.

Distance (mm) 3 sec 5 sec 10 sec 15 sec 300 35.1 43.9 58.2 77.1 250 41.7 45.9 66.7 86.9 200 50.3 53.4 74.3 103.2 150 59.6 62.4 97.9 144.5 100 64.4 90.7 149.1 186.2 50 72.1 132.1 185.5 229.8

On the other hand, the distance (L) between the heating means 261 and the photosensitive belt 110 may be selected and used in the range shown in Table 1 in consideration of the amount of the liquid carrier to be dried, the target temperature and time.

The heating means 261 may be provided in plurality. When a plurality of heating means 261 are installed, the area in which the electrostatic latent image formed on the photosensitive belt 110 is exposed to near infrared rays is increased, thereby increasing the ability to evaporate the liquid carrier.

The reflecting plate 263 is surrounded by the manifold 265 and is provided to surround the heating means 261. Of the radiant heat generated by the heating means 261, the heat radiated toward the reflecting plate 263 is reflected toward the photosensitive belt 110 and transferred to the photosensitive belt 110. Accordingly, the irradiation of the radiant heat generated by the heating means 261 may help evaporation of the liquid carrier buried in the surface of the photosensitive belt 110, thereby preventing the radiant heat from being lost and increasing its efficiency. .

The reflecting plate 263 is θ = 45 with respect to the heating means 261 so that the heat generated from the heating means 261 can be reflected to the photosensitive belt 110 to increase the thermal efficiency of the heating means 261. It is preferable to install at degrees.

The manifold 265 is a space surrounding the heating means 261 to form a closed space to temporarily request the gas carrier evaporated from the photosensitive belt 110. The manifold 265 is connected to a carrier recovery device (not shown), so that the gas carrier evaporated by the heating means 261 is recovered.

3 is a view showing the operation of the photosensitive belt drying apparatus 260 according to the present invention.

Referring to FIG. 3, the electrostatic latent image T1 formed on the photosensitive belt 110 by the laser scanning unit 130 and the developing device 140 shown in FIG. 2 is mixed with a liquid carrier and a toner. When the electrostatic latent image T1 enters the drying apparatus 260 in a state in which the electrostatic latent image T1 is attached to the photosensitive belt 110, the heating means 261 emits near infrared rays to bury the liquid carrier buried in the latent electrostatic image T1. By evaporating the liquid carrier is evaporated electrostatic latent image (T2). At this time, the reflecting plate 263 reflects the heat emitted from the heating means 261 toward the electrostatic latent image (T1). Only the toner remains in the electrostatic latent image T3 having the liquid carrier evaporated by the heating means 261. The electrostatic latent image T3 is printed on the recording paper 126 by the transfer roller 124 shown in FIG. On the other hand, the gas carrier evaporated by the heating means 261 is temporarily accommodated in the manifold 265, and is recovered by a carrier recovery device (not shown).

As described above, the photosensitive belt drying apparatus of the wet electrophotographic printer according to the present invention

First, the drying apparatus is a non-contact method with respect to the photosensitive belt can solve the picking (picking) phenomenon, and can improve the image quality because it does not affect the image (defect).

Second, since the near-infrared can be instantaneously reached to use temperature, there is an effect of shortening the time to warm up.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary and will be understood by those skilled in the art that various modifications and variations can be made therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (4)

At least one heating means installed to be spaced apart from the photosensitive belt by a predetermined length to generate heat for drying and evaporating the liquid carrier buried in the photosensitive belt; Reflection means installed adjacent to the heating means to reflect heat generated by the heating means toward the photosensitive belt; A manifold surrounding the heating means and the photosensitive belt and collecting gas carriers evaporated by the heating means; Photosensitive belt drying apparatus of a wet electrophotographic printer comprising a. The method of claim 1, The heating means is a photosensitive belt drying apparatus of a wet electrophotographic printer, characterized in that the near infrared heater. The method of claim 2, The near-infrared heater is a photosensitive belt drying device of a wet electrophotographic printer, characterized in that the wavelength is 1.3㎛. The method of claim 1, And said reflecting means is provided adjacent to said heating means so that heat emitted in a direction opposite to said photosensitive belt is horizontally incident on said photosensitive belt.