KR19990070639A - Electrophotographic printer with dryer - Google Patents

Abstract

An electrophotographic printer having a dryer device is disclosed. According to the present invention, there is provided a photosensitive belt, at least one developing device for forming a toner image on the photosensitive belt, and a hot air distribution unit installed in proximity to the photosensitive belt to distribute hot air to the toner image formed on the photosensitive belt. And, there is provided an electrophotographic printer having a dryer device consisting of a hot air generating unit for sending high temperature air to the hot air distribution unit. In the electrophotographic printer equipped with the dryer device according to the present invention, the liquid carrier can be effectively recovered from the toner image formed on the photosensitive belt by the developing device, so that an optimum transfer operation is achieved.

Description

Electrophotographic printer with dryer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic printer having a dryer device, and more particularly, to an electrophotographic printer having a dryer capable of injecting air of a predetermined temperature to a toner image formed on a photosensitive belt.

Generally, an electrophotographic printer is applied to a laser printer or a copying machine for a computer, which is a dry type using a powder toner as a developing method and a wet type using a liquid toner mixed in a carrier. In both of these methods, a desired image can be printed on a paper by transferring a charged toner or a liquid toner to a photosensitive medium on which a latent electrostatic image is formed, and then passing the paper between the rotating transfer media in contact with the photosensitive medium. have. However, the dry toner type printer has a problem of resolution caused by a limited size of the toner particles used, or a problem that toner dust is very harmful to the human body. Therefore, a developing method using liquid toner is now employed in earnest. It is becoming.

In an electrophotographic printer, a photosensitive belt or photosensitive drum rotatably held on a roller is used. As is known, the surface of the photosensitive belt may not only be charged, but also the potential level may be converted by scanning of the beam.

1 shows a schematic configuration diagram of a general wet printer.

Referring to the drawings, the printer 10 includes a photosensitive belt 14 rotating at an endless track while being supported by a driving roller 11, a steering roller 12, a counter roller 13, and at least one or more developing devices. 17a, 17b, 17c, and 17d and the transfer roller 25 are included. The surface of the photosensitive belt 14 is charged by the corona device 16, and the charging state of the surface of the photosensitive belt 14 is installed in the vicinity of the developing devices 17a, 17b, 17c, and 17d, respectively. The potential can be changed by scanning a laser beam from 18d). Beam scanning by the laser scanning devices 18a, 18b, 18c, and 18d forms an electrostatic latent image on the surface of the photosensitive belt.

The developing units 17a, 17b, 17c, and 17d can develop black, yellow, cyan, and magenta colors according to the color of the pigment, and also the laser scanning device 18a. , 18b, 18c, and 18d also form an electrostatic latent image for the color. The developing units 17a, 17b, 17c, and 17d are filled with a liquid mixture of the ink toner of the corresponding color and the carrier. The liquid mixture used in the developing units 17a, 17b, 17c, and 17d includes ink stored in the ink containers 19a, 19b, 19c, and 19d and carriers stored in other storage means (not shown). In the appropriate concentration in 21d). This ink is transferred from the ink container to the mixer by pumps 20a, 20b, 20c, and 20d, and again from the mixer to the developer by pumps 22a, 22b, 22c, and 22d. The drying roller 23 has a function of completely removing the liquid carrier from the toner image formed on the photosensitive belt 14, and the heating roller 24 functions as the drying roller 23 by evaporating the liquid carrier. To assist. The toner image attached to the photosensitive belt 14 is transferred to the transfer roller 25, and can be transferred from the transfer roller 25 to the printing paper 27 by the surface energy difference. The eraser 15 performs a function of completely removing the charged state remaining on the photosensitive belt 14 so that a new electrostatic latent image can be formed.

FIG. 2 is a diagram illustrating in detail the configuration of one of the developing devices shown in FIG. 1, and the same components as those of FIG. 1 are denoted by the same reference numerals.

Referring to the drawings, the developing unit 17a is installed in close proximity to one side of the photosensitive belt 14, and in the developing unit 17a, the developing roller 39, the first squeegee roller 31, and the second squeegee roller ( 32) is installed. In addition, the cleaning roller 36 is provided inside the developing unit 17a in proximity to the developing roller 29, and each of the squeegee rollers 31 and 32 has a first blade 33 and a second corresponding to each other. The blade 34 is provided. Further, the developing roller 29 and the first squeegee roller 31 correspond to the two counter rollers 30 with the photosensitive belt 14 interposed therebetween. The developing roller 29 serves to attach the mixture of the ink toner and the carrier supplied through the nozzle 35 to the photosensitive belt 14 on which the electrostatic latent image is formed. The first and second squeegee rollers 31 and 32 form a film of the ink toner and the carrier which form the toner image, and at the same time, the surface of the photosensitive belt 14 receives ink toner and the carrier which do not contribute to the toner image formation. It serves to remove from. The blade 34 is arranged to contact the squeegee rollers 31 and 32, thereby functioning to drop the ink and the mixture absorbed on the surfaces of the squeegee rollers 31 and 32 to the developing unit 17a.

In the electrophotographic printer as described above, the toner image formed on the photosensitive belt by the developing units 17a, 17b, 17c, and 17d is greatly affected by the operation of the squeegee rollers 31 and 32. Quality directly affects transcription. Therefore, it is necessary to maintain the operation of the squeegee rollers 31 and 32 in an optimal state. In particular, the pressure distribution of the squeegee roller, the surface roughness of the roller, the humidity and the temperature around the developer, and the like are important for forming the toner image by the squeegee roller. It acts as an argument.

According to the prior art, since the operation of removing the carrier in the liquid state from the toner image is performed solely by the squeegee rollers 31 and 32, the operation of the squeegee rollers 31 and 32 is not normally performed, or the ambient temperature and If the humidity is too high or too low, the print job may not have worked properly. That is, since the carrier cannot be removed from the toner image in a sufficiently controllable manner, the quality of the final printed product itself is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an electrophotographic printer having a dryer device capable of controllably removing a carrier from a toner image formed on a photosensitive belt. will be.

1 is a schematic configuration diagram of a general electrophotographic printer.

FIG. 2 is a schematic configuration diagram of a developer of the printer shown in FIG. 1. FIG.

Figure 3 is a schematic configuration diagram of a printer with a dryer device according to the invention.

Figure 4 is a schematic perspective view of the hot air distribution of the dryer device according to the invention.

Brief description of the main symbols in the drawings

11. Drive roller 12. Steering roller

13. Counter roller 14. Photosensitive belt

15. Eraser 16. Corona device

17a.17b.17c.17d. Developer 18a.18b.18c.18d. Laser scanning device.

23. Cleaning Roller 24. Heating Roller

29. Developing roller 31.32. Squeegee roller

34. Blade 38. Holder

41. Hot air generator 42. Hot air distributor

43. Euro 44. Motor

45. Fan 47. Filter

In order to achieve the above object, there is a photosensitive belt, at least one developing device for forming a toner image on the photosensitive belt, hot air installed in proximity to the photosensitive belt to distribute hot air to the toner image formed on the photosensitive belt. An electrophotographic printer having a distribution unit and a dryer device comprising a hot air generation unit for sending hot air to the hot air distribution unit.

According to an aspect of the present invention, the hot wind generating unit includes a fan that is rotationally driven by a motor, a hot wire for heating the air sent by the fan, and a filter for filtering the air introduced into the hot wind generating unit.

According to another feature of the invention, the hot air distribution unit is formed with a plurality of distribution holes through which the air generated from the hot air generating unit can be distributed, these distribution holes are disposed in close proximity to the width direction of the photosensitive belt.

According to another feature of the present invention, the hot air distributor is provided downstream of the developing devices in the advancing direction of the photosensitive belt.

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

3 is a schematic configuration diagram of an electrophotographic printer equipped with a dryer device according to the present invention.

Referring to the drawings, the same reference numerals as those shown in Fig. 2 among the reference numerals shown in Fig. 3 represent the same configuration. In brief, the developing unit 17a is installed close to one side of the photosensitive belt 14, and the developing roller 29, the first squeegee roller 31, and the second squeegee roller ( 32) is installed. The cleaning roller 36 is provided inside the developing unit 17a, and each of the squeegee rollers 31 and 32 is provided with a first blade 33 and a second blade 34 corresponding thereto. The developing roller 29 and the first squeegee roller 31 correspond to the two counter rollers 30.

According to a feature of the invention, one side of the developing device is provided with a dryer device. The dryer device includes a hot wind generator 41 that generates hot air, and a hot wind distributor 42 capable of injecting air generated from the hot wind generator 41 into the photosensitive belt 14. The hot air distribution unit 42 may be installed between the developing units 17a, 17b, 17c, and 17d in FIG. 1, or may be provided only one downstream of the last developing unit 17d in the advancing direction of the photosensitive belt 14. There will be. The hot air distributor 42 preferably has a shape and structure in which hot air distributed therefrom can be uniformly distributed to the toner images formed on the photosensitive belt 14.

The hot air generating unit 41 is provided with a fan 45 capable of blowing air and a hot wire 46 capable of raising the temperature of the air. The fan 45 is driven to rotate by the motor 44, and the air in the hot air generator 41 is heated by the hot wire 46. The filter 47 may be installed at one side of the hot air generator 41. Dust particles included in the air introduced into the hot air generator 41 may be filtered by the filter 47.

The hot air sent out from the hot wind generator 41 flows to the hot wind distributor 42 through the flow passage 43. The portion where the air is discharged from the hot air distribution unit 42 is provided in proximity to the photosensitive belt 14, whereby the toner image formed on the photosensitive belt 14 can be dried by hot air.

4 is a perspective view showing that the hot air distributor is installed close to the photosensitive belt.

Referring to the drawings, a plurality of distribution holes 48 are formed in the upper portion of the hot air distribution unit 42. These distribution holes 48 are arranged over the width of the photosensitive belt 14, so that hot air distributed through the distribution holes 48 can dry the photosensitive belt 14 over the width. That is, while the photosensitive belt 14 passes through the upper part of the hot air distribution part 42, the toner image formed on the photosensitive belt 14 can be dried over the width | variety. Although the distribution holes 48 are formed in a line in the drawing, in other embodiments, they may be formed in one or more lines.

Normally, at least about 70% of the liquid carrier has to be recovered from the toner image formed by the developing roller 39 to achieve a good transfer operation. When only a squeegee roller was used without a dryer device, the recovery rate of the liquid carrier could not exceed 60% due to the pressure distribution of the squeegee roller or the change in temperature and humidity. However, when applying the dryer apparatus of the present invention, the recovery rate of the liquid carrier can be controlled to the optimum state in the range of 70% or more. For example, by controlling the rotational speed of the fan 45, the air delivery amount is controlled, the air temperature by the hot wire 46 is controlled, and the dryness of the toner image is arbitrarily controlled by adjusting the number of the through holes 48. I can regulate it.

In the electrophotographic printer equipped with the dryer device according to the present invention, the liquid carrier can be effectively recovered from the toner image formed on the photosensitive belt by the developing device, so that an optimum transfer operation is achieved. In addition, it is possible to prevent contamination of the photosensitive belt by excessive liquid carriers, and has the advantage of changing the design manner in which recovery of the liquid carriers depends only on the squeegee roller.

Although the present invention has been described with reference to one embodiment shown in the accompanying drawings, this is only an example, and those skilled in the art may understand that various modifications and equivalent other embodiments are possible therefrom. There will be. Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

Claims (4)

Photosensitive belt, At least one developer for forming a toner image on the photosensitive belt, It is provided with a dryer device comprising a hot air distribution unit which is installed in close proximity to the photosensitive belt to distribute the hot air to the toner image formed on the photosensitive belt, and a hot air generating unit for sending hot air to the hot wind distribution unit. One electrophotographic printer. The hot air generating unit of claim 1, Fan driven rotationally by motor, A heating wire for heating the air sent by the fan, And a filter for filtering the air flowing into the hot air generating unit. The hot air distribution unit is formed with a plurality of distribution holes through which the air generated from the hot air generation unit can be distributed, and the distribution holes are disposed in close proximity to the width direction of the photosensitive belt. An electrophotographic printer equipped with a dryer device. The electrophotographic printer with a dryer device according to claim 1, wherein the hot air distribution unit is provided downstream of the developing devices in a traveling direction of the photosensitive belt.