US3689147A

US3689147A - Liquid-development type electrophotographic apparatus including paper drier means

Info

Publication number: US3689147A
Application number: US167745A
Authority: US
Inventors: Shigeru Suzuki
Original assignee: Individual
Current assignee: Individual
Priority date: 1967-12-20
Filing date: 1971-07-30
Publication date: 1972-09-05
Anticipated expiration: 1989-09-05
Also published as: NL6817206A; GB1252910A; FR1595811A

Abstract

A drier for drying copying paper in a liquid development type electrophotography apparatus includes a pair of squeegee rollers, and a pair of drier rollers provided next to the squeegee rollers. The peripheral surface of at least one of the drier rollers consists of a liquid-absorbing material. Air is evacuated from within a perforated endless belt to suck paper thereagainst for purposes of transportation. This air is moved past an exposure lamp where the air is heated and dried. The air is then blown against the liquid absorbing material and against copying paper passing therethrough.

Description

United States Patent Su uk 1 Sept. 5, 1972 [54] LIQUID-DEVELOPMENT TYPE [56] References Cited ELECTROPHOTOGRAPHIC APPARATUS INCLUDING PAPER UNTTED STATES PATENTS DRIER MEANS 3,282,177 11/1966 Stanton ..355/l 3,345,925 /1967 Ostensen ..355/ 10 [72] Inventor: Shigeru Suzuki, 440-Marooka-cho, 3,345,926 10/ 1967 Tiger et al ..355/l0 X Kohoku-ku, Kanagaua-ken, 3,441,345 4/1969 Kolibas ..355/l0 Yokohama-shi, Japan Primary Examiner-Samuel S. Matthews [22] Filed. July 1971 Assistant Examiner-Fred L. Braun 1 1 pp 167,745 Attorney-Erich H. Waters et a1.

Related US. Application Data [57] ABSTRACT [63] Continuation-impart of Ser. No. 783,550, Dec. A drier for drying copying Paper in a liquiFl develop 13 1963, abandoned ment type electrophotography apparatus includes a pair of squeegee rollers, and a pair of drier rollers provided next to the squeegee rollers. The peripheral sur- [30] Forelgn Apphcat'on Pnomy Data face of at least one of the drier rollers consists of a Dec. 20, 1967 Japan ..42/81182 liquid-absorbing material Air is evacuated from within a perforated endless belt to suck paper [52] US. Cl. ..355/10, 34/70, 34/155, thereagainst for p p of transportation This air is /89 A moved past an exposure lamp where the air is heated [51] Int. Cl. ..G03g 15/10 and dried. The air is then blown against the liquid ab- [58] Field of Search ..355/3, 10; 95/89 R, 89 A; sorbing material and against copying paper passing 34/70, 151, therethrough.

9 Claims, 4 Drawing Figures PATENTEDsEP 51972 SHEET 1 BF 4 FIG.

PATENTEDS-EP S1972 3.689.147

I sum 2 or 4 FIG; 2

PATENTEUSEP 5 m2 SHEU t [If 4 LIQUID-DEVELOPMENT TYPE ELECTROPHOTOGRAPHIC APPARATUS INCLUDING PAPER DRIER MEANS OTHER APPLICATIONS This is a continuation-impart of earlier application, Ser. No. 783,550, filed Dec. 13, 1968 and now abandoned.

FIELD OF INVENTION The present invention relates to copying paper drier devices for electrophotographic apparatus of the type which employs a liquid development system.

BACKGROUND In electrophotographic devices of the type mentioned above, it is conventional to place a pair of squeegee rollers immediately following a developer tank to receive copying paper which after passing through the squeegee rollers is dried by the flow of ambient or heated air.

In an electrophotographic device of the type in connection with which a photoconductive layer consisting of a zinc oxide composition constitutes a coating on the copying paper, the photosensitive surface of said copying paper is smooth and a film of developer solution will remain on the smooth surface even after passage of the copying paper through the squeegee rollers. This developer solution film cannot be eliminated easily in a subsequent drying process and, as a result, the copying paper comes out of the machine incompletely dried.

Drying devices are known for various purposes. Thus, for example the Minnis US. Pat. No. 1,982,116 relates to a fruit dryer wherein rollers are employed each of which is covered with a hygroscopic material such as felt. Such patents however, do not generally relate to the improvements of the invention.

The Jenkins US. Pat. No. 3,431,050 relates to an electrophotographic copying machine which employs pressure rollers for positioning developed copy paper at the exit of a developer liquid tank and a heater for drying this copy paper. The technique employed for drying copy paper is not very efficient nor effective and the apparatus disclosed by this patent fails to employ improvements of the invention, such as a blotter roller as described in greater detail hereinafter.

SUMMARY OF INVENTION It is an object of the present invention to avoid the defects mentioned above.

It is a further object of the present invention to provide an improved copying paper dryer device which effectively and efficiently dries copying paper upon the exit of the same from a developer tank.

Yet another object of the invention is to provide an improved dryer device which efficiently makes use of air available within the equipment while efficiently utilizing an exposure lamp to heat and dry the air before the air is further employed for drying the blotter roller and for further drying the paper after it has passed through the blotter roller.

In achieving the above and other objects of the invention there is provided a copy paper dryer for a liquid developing type electrophotographic reproduction apparatus which comprises a light source for the exposure of a photosensitive sheet and a developer tank containing a liquid developer. Furthermore, there is provided means for feeding the exposed photosensitive sheet into and through the liquid developer in the developer tank. This means includes a perforated endless belt defining an internal chamber adapted to engage the aforesaid sheet.

A pair of squeegee rollers is provided at the exit of the tank to receive the sheet therefrom. A pair of drier rollers is positioned adjacent the squeegee rollers and downstream of the same for receiving the sheet therefrom. One of the drier rollers includes an outer coating of a liquid absorbing material. The other of the drier rollers isconstituted of a hard material which presses the photosensitive sheet into pressure contact with the first said roller.

In accordance with the invention there is provided means to evacuate air from the internal chamber of the belt and move the same past the light source to heat and dry the air and to discharge the thusly heated and dried air, first against the liquid absorbing material of said one roller and then into contact with the photosensitive sheet.

It is furthermore an object of the invention to provide an improved drying apparatus which can readily dry a copying paper without destroying the image thereon.

With the above and other objects in view, the invention will become apparent from the following detailed description taken in connection with the accompanying drawing, in which:

BRIEF DESCRIPTION OF DRAWING FIG. 1 is a diagrammatic cross sectional view of a drier means according to the present invention;

FIG. 2 is a cross sectional view taken longitudinally through an electrophotographic apparatus provided with the improvements of the invention;

FIG. 3 is a rear view of the apparatus illustrated in FIG. 2; and

FIG. 4 is a partially diagrammatic view showing the passage of dried and heated air through the apparatus of the invention.

DETAILED DESCRIPTION A copying paper 2 which has been developed in a developer tank 1 is squeezed by a pair of squeegee rollers 3 and 4 which are placed just after the developer tank 1.

The squeegee rollers consist of a metallic roller 3 and a rubber roller 4. The metallic roller 3 is electrically grounded. This has the effect of preventing an edge effect in the solid image area as well as of preventing the so-called offset effect of transferring the toner of the image on the copying paper to the squeegee rollers. Furthermore, the metallic roller 3 promotes the development of the coping paper with the developer solution being squeezed out to the entrance of the copying paper to the squeegee rollers.

The copying paper 2 which has passed through the squeegee rollers is further transferred by a pair of drying rollers 5 and 6. The photosensitive surface of the copying paper 2 is difficult to dry, especially, when a metallic roller is used. A blotter roller is therefore provided on the side of the photosensitive surface. Thus the upper roller 5 of the drying rollers has a liquid-absorbing material such as blotting paper, liquid-absorbing felt or the like on the peripheral surface 8 of a metallic cylinder 7. The lower roller 6 is preferably a metallic or a rubber roller. After passing through the squeegee rollers 3 and 4, any film of developer solution which still remains on the photosensitive surface is substantially removed during the passage of the copying paper through the drying rollers by being pressed against the liquid-absorbing peripheral surface of the rollers 5. Thereafter, the copying paper 2 follows a path 9 and exits from the machine through a pair of

exit rollers

10 and 11.

A flow of air is discharged through an opening 12 from a blower and passes around the roller 5 in the direction shown by arrow 13, and travels to the right along the path 9 as shown by arrow 14, and exits from the machine. The air flow mentioned above, in flowing around the roller 5, dries the peripheral surface 8 of the liquid-absorbing material which has been dampened by the wet copying paper so that the peripheral surface is always kept dry to dry the copying paper most effectively.

It is preferable that the air flow mentioned above be heated as this not only promotes drying of the peripheral surface of the roller 5, but also dries and finishes the copying paper which has passed through the drying rollers 5 and 6. The heating of the air flow can be achieved by means of an electric heater, and it is also possible to use the heat generated by a high-intensity lamp in the exposure station. The latter is quite advantageous in view of the available source of heat.

While the present invention has been particularly described in terms of a specific embodiment thereof, it is to be understood that numerous variations and modifications may be readily devised by those skilled in the art without departing from the scope of the inventlon.

FIG. 2 illustrates an electrophotographic apparatus including the improvements of the invention, said apparatus and improvements being shown in greater detail than in FIG. 1.

The apparatus of FIG. 2 includes a casing having an upper station 22 at which photosensitive sheets may be placed for purposes of exposure, the exposure being effected through a mobile light source 24 details of which are not essential to an understanding of the present invention except for the fact that this system is a source of heat which is employed for heating and drymg am When a copy sheet has been exposed at the station 22 it is removed to section 26 whereat the sheet passes through rollers onto a perforated belt 28 having an internal chamber 30. The perforated belt is supported on

rollers

32, 34, 36 and 38 by means of which the belt 28 which is an endless belt is transported along an endless path.

As will be shown hereinafter air is evacuated from the internal chamber 30 thereby sucking the paper against the belt whereby the paper is effectively and positively transported towards and into a tank 40 which is the developer tank and includes a liquid developer for developing the electrostatic image which has been placed upon the copy sheet by a conventional technique which is well known in the art.

Supported downstream of the belt 28 and a guide 42 which serves to direct the copy paper in a curvilinear path are a pair of squeegee rollers 44 and 46, these squeegee rollers serve the purpose which has been indicated hereinabove.

Downstream of the squeegee rollers is a pair of further or drier rollers 48 and 50 whereof the roller 50 is the blotter roller and is provided with a liquid-absorbing material such as blotter paper or the like- The copy paper moves through the developer tank 40 and through the squeegee rollers 44 and 46, passing thereafter through the drier rollers 48 and 50 and than exiting from the machine through a pair of rollers 52 and 54, the latter being supported on a spring 56 for the firm and effective guiding of the copy paper from the machine.

In FIG. 3 appears a blower 58 the purpose of which is to transport the heated and dried air as referred to generally hereinabove. Also appearing in FIG. 3 is an air manifold 60 the function of which will become apparent hereinafter. Other parts of the apparatus illustrated in FIG. 3 such as for example the control circuitry 62 while being essential to the operation of the equipment of purposes of reproduction are not essential to an understanding of the present invention and consequently will not be explained in detail in this text.

Referring next to FIG. 4 it is seen that the blower 58 has a suction side connected through a hood 64 and an opening 66 to the internal chamber 30 of the perforated belt 28 at a consequence whereof air is sucked from the chamber 30 and is caused to flow through the blower 58 and an opening 68 into the channel 70 which passes by at least one and preferably a series of lamps 72 which are a part of the mobile system 24 referred to hereinabove with respect to FIG. 2. By coming into contact and flowing past such lamps the air evacuated from internal chamber 30 is heated and dried and is as a consequence available for the drying of the blotter material referred to hereinabove and for drying the copy paper itself.

Air from the channel 70 passes into an opening 74 and into manifold 60 and out through opening 76 to flow across the blotter material of the roller 50 and thence along the path indicated by arrow 78 to come in to contact with and engage the copy paper directly for a drying of the same.

Stated otherwise the air from the internal chamber of the perforated belt is discharged into a channel in which is located the mobile optical system, the movement of the air being effected by a blower. The heated and dried air is discharged as copy sheet drying air while this air also has the effect of cooling the lamps in the mobile optical system. This air dries the blotter roller since the material of the blotter roller is especially susceptible of being dried by the mobile heated air being for example of a material such as ordinary blotting paper.

In general the system of the invention is characterized by the fact that the air evacuated from the internal chamber of the perforated belt is employed as cooling air for the exposure lamps whereafter the thusly heated and dried air is employed to dry the blotter roller and thereafter employed for drying the surfaces of the copy sheets themselves.

In the aforesaid apparatus the driving of the squeegee and blotter rollers is performed through a common gear train, these rollers thus being characterized by the same peripheral speed.

From the above it will be seen that there is provided a copy paper dryer for a liquid developing type electrophotographic reproduction apparatus which comprises a light source for the exposure of a photosensitive sheet, a developer tank containing a liquid developer and means feeding the exposed photosensitive sheet into and through the liquid developer in the tank, said means including a perforated endless belt defining an internal chamber and adapted to engage the aforesaid sheet. Furthermore, there is provided a pair of squeegee rollers at the exit of the tank to receive the sheet therefrom and a pair of drier rollers positioned adjacent and downstream of the squeegee rollers for receiving the sheet therefrom. One of the drier rollers includes an outer coating of a liquid-absorbing material, the other of the drier rollers being constituted of a hard material and pressing the photosensitive sheet into pressure contact with the first said roller. Furthermore, there is provided means to evacuate air from the internal chamber of the aforesaid perforated belt and move the same past the light source to heat and dry the air and to discharge the thusly heated and dried air, first against the liquid-absorbing material of the blotter roller and then into contact with the photosensitive sheet.

There will now be obvious to those skilled in the art many modifications and variations of the structure set forth hereinabove. These modifications and variations will not depart from the scope of the invention if defined by the following claims.

What is claimed is:

l. A copy paper drier for a liquid development type electrophotographic reproduction apparatus which comprises a light source for the exposure of a photosensitive sheet, a developer tank containing a liquid developer, means for feeding the exposed photosensitive sheet into and through the liquid and downstream of the squeegee rollers for receiving the sheet therefrom, one of said drier rollers including an outer coating of a liquid-absorbing material, the other of the drier rollers being constituted of a hard material and pressing the photosensitive sheet into pressure contact with said one drier roller, and means to evacuate air from the internal chamber of said belt and move the same past said light source to heat and dry the air and to discharge the thusly heated and dried air first against said liquid-absorbing material of said roller and then into contact with said photosensitive sheet.

2. Adrier as claimed in claim 1 wherein said evacuating means includes an air duct and said one drier roller has an upper portion which projects into said duct, said sheet passing from said drier rollers into said duct.

3. A drier as claimed in claim 2 wherein said liquidtqk iifi i a c ai r ngifiii i: 31 2 comprising exit rollers in said duct for engaging said sheet to pass the sheet from said duct, the air passing through said duct with said sheet towards said exit rollers.

5. A drier as claimed in claim 2 wherein said evacuating means includes a blower having a suction side coupled to the internal chamber of said belt.

6. A drier as claimed in claim 2 wherein said light source is a high intensity lamp.

7. A drier as claimed in claim 1 wherein one of said squeegee rollers is metallic and the other of said squeegee rollers is rubber.

8. A drier as claimed in claim 7 comprising means grounding the metallic squeegee roller.

9. A drier as claimed in claim 8 wherein said one drier roller includes an inner annular metallic portion covered by said liquid-absorbing material.

Claims

1. A copy paper drier for a liquid development type electrophotographic reproduction apparatus which comprises a light source for the exposure of a photosensitive sheet, a developer tank containing a liquid developer, means for feeding the exposed photosensitive sheet into and through the liquid developer in the developer tank, said means including a perforated endless belt defining an internal chamber and adapted to engage said sheet, a pair of squeegee rollers at the exit of the tank to receive said sheet therefrom, a pair of drier rollers positioned adjacent and downstream of The squeegee rollers for receiving the sheet therefrom, one of said drier rollers including an outer coating of a liquid-absorbing material, the other of the drier rollers being constituted of a hard material and pressing the photosensitive sheet into pressure contact with said one drier roller, and means to evacuate air from the internal chamber of said belt and move the same past said light source to heat and dry the air and to discharge the thusly heated and dried air first against said liquid-absorbing material of said roller and then into contact with said photosensitive sheet.

2. A drier as claimed in claim 1 wherein said evacuating means includes an air duct and said one drier roller has an upper portion which projects into said duct, said sheet passing from said drier rollers into said duct.

3. A drier as claimed in claim 2 wherein said liquid-absorbing material is blotter paper.

4. A drier as claimed in claim 2 comprising exit rollers in said duct for engaging said sheet to pass the sheet from said duct, the air passing through said duct with said sheet towards said exit rollers.