Tabletop Electrostatic Copying Machine

Abstract

A tabletop electrostatic copying machine has a tunnel opening for the original. The copy paper moves in a path with few bends past the exposure station synchronized with the moving original. Liquid toner is applied to only one face of the copy to minimize drying time. The bottom of the housing is a reservoir for the toner and excess toner from the copy paper falls there.

Description

The general principles of electrostatic printing and developing or toning are well known and need not be summarized at this point. Suffice it to say that the present machine is of the type using a paper having a coating such as zinc oxide capable of receiving an electrostatic charge which is partially or completely dispelled by light falling thereon. A toner is used to fix the electrostatic image.

There are many electrostatic copying machines now on the market. By and large, these machines are subject to certain deficiencies, mainly being too expensive and too large. Others are too noisy, while most take too long to produce a finished print. Man discharge the finished print and the material to be copied essentially at the same location thus allowing the possibility of intermixing the prints and original material.

In accordance with the present invention, it is an object thereof to provide an inexpensive and compact tabletop electrostatic copying machine of superior characteristics.

In particular, it is an object of the present invention to provide such a machine in which the paper on which prints are made to travels over short path thus making the finished print accessible at the earliest possible time.

Furthermore, it is an object of the present invention to provide a tabletop electrostatic photocopying machine wherein material to be copied is fed from side-to-side across the machine, and wherein the printing paper is fed along a curvilinear path across, down and across the machine, to be delivered from the front thereof directly to the operator.

It is a further object of the present machine to provide a liquid toner reservoir of maximum capacity for the limited size of the machine.

Yet another object of the present invention is to deliver the finished liquid toned print to a grid support for air-drying of both sides of the print.

Other and further objects and advantages of the present invention will be apparent from the following description when taken in connection with the drawings, wherein:

FIG. 1 comprises a perspective view of a tabletop electrostatic copying machine constructed in accordance with the principles of the invention; and

FIG. 2 comprises a longitudinal section therethrough.

Turning now to the drawings in greater particularity a tabletop copying machine in accordance with the present invention is designated generally by the numeral 10, and includes an external housing or casing 12 of generally rectangular configuration. This housing or casing fits over a frame 14 to which it is held by any suitable or conventional means, such as screws. The housing is provided at the upper portion thereof with sloping plate 16 on which sheet 18 to be copied is placed. The plate 16 is hingedly secured to the remainder of the housing at 20 for lifting of the sheet to permit access to a paper safe 22, as will be explained presently.

Immediately to the left of the plate 16, as viewed in the drawings, is a tunnel 24 into which the sheet 18 is urged by hand. The sheet is picked up by a pair of opposed resilient rollers 26, and is fed between a pair of upper and lower guide plates 28. A switch 30, shown schematically, is positioned adjacent the guides 28, and senses the presence of paper fed therethrough. Although many types of switches could be used including photocell switches, I prefer to use one having a low travel and operates at a very low pressure. This switch turns on certain parts of the machine a will be brought out hereinafter.

From the guide 28, the paper or other sheet 18 to be copied feeds between exposure guides 32 which are likewise horizontally disposed. These guides, like the guides 28, are provided with beveled or flared receiving edges 34 to insure centering of the paper fed therethrough. The guides 32 alternatively may comprise metal or plastic side guides with the paper simply supported therebetween or in some cases they may comprise glass plates through which exposure is made. From the guides 32 the paper to be copied passes between roller 36 to be fed of the machine as indicated by the arrow a 38, from whence it will drop on the supporting table 40 for subsequent handling.

A light reflector 42 is provided below and to the right of the exposure guides 32, and has an upper reflecting surface which is curvilinear in the longitudinal section shown and which is straight across transversely thereof. The lower reflecting surface is joined at 44 to an upper reflecting surface 46, which is likewise curvilinear but which is concave down, whereas the reflecting surface 42 is concave up. The two surface or members 42 and 46 are supported from the frame 14 by means such as ears or tab 48 secured to the frame by any suitable means such as screws or rivets. A tubular light 50 of known design is supported between the reflecting member or surfaces 42 and 46, whereby light is directed upwardly as indicated by the diagonal lines to the area of the exposure guides 32 for illuminating the sheet 18 as it passes between the guide.

A mirror 52, preferably of the type having a front-reflecting surface is supported from the frame a 45.degree. angle directly below the exposure guides 32. The image illuminated between the exposure guides is reflected from the mirror 52 through a line indicated at 54 through a tunnel 55 over to the right end of the machine to an exposing area 56 including a pair of vertically disposed guides 58. These guides have beveled receiving upper edges 60 to center paper passing therethrough as will be mentioned hereinafter, and the guides are similar to the exposure guides 32.

An electric motor 62 is disposed centrally of the machine, and has electric wires (not shown) connected thereto from unit indicated at 64 as "CONTROLS, POWER SUPPLY, AND PUMP." A flexible line cord of the usual variety (not shown) lead from the unit 64 to a wall outlet. The motor drive has an output shaft on which is mounted a cog unit 66 which, in the illustrative example simply may comprise two cogs mounted end-to-end with a slight spacing therebetween. The motor may drive the cogs directly, or through a gear reducing unit in accordance with the characteristics of the motor. A drive chain is indicated in broken lines a 68, and passes over cogs 70 and 72 on the upper ones of the roller pair 36 and 26 to drive these rollers in the proper direction with the cog 66 turning in a clockwise direction. The lower rollers of the roller pairs 36 and 26 may also be positively driven by any known or suitable means, or they may be driven frictionally from the opposed rollers of each pair.

The paper safe 22 mentioned previously includes a supporting plate 74 pivotally mounted at the left-hand end a 76, and spring-pressed upwardly by a spring 78. A stack OF paper 80 is supported on top of the plate and the paper is of the type suitable for electrostatic charging and generally including zinc oxide coating. A rubber drive roller 80 (which may be two or more axially spaced rollers) overlie the stack of paper 80, and is engageable with the top sheet 82 thereof to feed it between a diagonally upward lower guide plate 84, and an upper guide plate 86. The upper guide 86, which preferably is continuous across the machine, progresses from the horizontal receiving portion to a curved portion 88 turning slightly back at 90. A cured lower guide 92 underlies the guide 86, and includes a substantially vertical trailing portion 94 opposed to the outer guide portion 90.

The guide positions 90 and 94 lead to a pair of horizontally opposed rollers 96 which feed the sheet 82 down between a pair of guide 98 having outwardly flared receiving ends 100. As the paper passes between the guides 98, it activates a switch 102 of the same type as the switch 30. From the guides 98 the paper passes through an electrostatic charging unit 104 of known design which is turned on by the switch 102, power being supplied from the unit 64. The electrostatically charged paper then progresses down through the exposure area 56 previously described. At this point the paper is traveling at exactly the same rate a the copy sheet 18, and an image is formed electrostatically on the paper 82.

From the exposure area 56, the paper 18 progresses to a toning or developing unit 106 of the type set forth in some detail in Meyer L. Sugarman and Joseph H. Jaeger applications Ser. No. 692,234now abandoned, filed on Dec. 20, 1967 for "Compact Liquid Toner Apparatus with Straight-Through Feed". In brief summary, the developer unit 106 includes an outer curved guide 108 for directing the paper to a pair of infeed roller 110. The paper then progresses along the path indicated by the arrows 112 to a pair of outfeed rollers 114. In so doing, the papers passes beneath a distributor tube or pipe 116 having outlet holes as indicated at 118 along the bottom thereof, liquid toner being pumped into the distributor tube 116 as through a conduit 120. The liquid toner collects on the surface of the paper, forming a lake as indicated at 122. The liquid is squeegeed off of the paper by the roller 114, and falls into sump 124. The toned or developed paper then passes over a vertical barrier wall 124 and drops on a gridlike support 126 accessible through a side opening 128 in the housing 12, from which it can be removed by hand in a dry state.

The entire bottom of the copying machine comprises a reservoir as indicated at 130. Thus, a large volume of liquid toner can be stored without the necessity of an appreciable vertical height. Liquid toner passing from the sheet as it goes through the developing unit 125 drops gravitationally into a sump 132 which communicates with the reservoir 130, such as by means of drain holes 134, or any other suitable mean.

A drain or pickup tube or conduit 136, shown somewhat schematically at the lower right-hand corner of FIG. 2, is provided for draining fluid from the reservoir 130, from whence it passes to the unit 64 including pump. The liquid so pumped then passes from the unit through the tube or conduit 120 back to the distributor 116.

A cog 138 on a shaft on the unit 64 is driven from the motor drive cog 66 by means such as a chain indicated by the broken line 140. This chain also passes over a cog 142 on the leftmost of the roller pair 96, over a cog 144 on the uppermost of the roller pair 110, and over a cog 146 on the uppermost of the roller pair 146. As will be understood suitable idlers or tensioning cogs would be provided necessary. The cog 138 is a double cog, and an additional chain 148 passes over the second cog and over a cog 150 to drive the roller or rollers 80. The chain 148 also passes over a cog 150 to drive a cam 152 for lowering the paper safe plate 74 to drop the stack of paper 80 out of engagement with the roller 80 after the paper 82 has been engaged by the rollers 96. As will be set forth shortly hereinafter the roller 80 is only driven part of the time, and in a preferred embodiment of the invention, it is connected to the cog 150 by means such as a well-known electric clutch (not shown). Similarly, the cam 152 can be driven from the cog 150 by an electric clutch or this can be handled simply by the design of the cam and the speed at which it is driven.

OPERATION

The pivoted plate 16 is lifted at some time to place a supply of paper 80 in the paper safe 22, after which the plate is returned to its normal position and this need not be considered a part of the operation each time the machine is used. The machine is turned on by means of a switch of well known character (not shown) connected to the "CONTROLS, POWER SUPPLY, AND PUMP" unit 64.

Turning on of the switch, as just indicated, starts the motor drive 62. Placing of a sheet 18 to be copied on the support plate 16 and moving it manually to the left causes it to be picked up by the roller 26 which are now rotating. The switch is activated by the sheet, and this acts through the unit 64 to turn on the light 50, whereby the sheet is illuminated as it passes through the guides 32, and between the rollers 70 and at of the machine. The light turns off with a predetermined time delay after the switch 30 no longer senses the sheet to be copied.

Meanwhile, during the last previous copying application, the roller 80 has fed the top sheet of paper 82 approximately to the position shown in FIG. 2, with the lower end of the paper between the rollers 96. At the start of an operation, the rollers 80 are not activated, and the cam 152 holds the plate 74 somewhat down so that the sheet 82 is not arrested in a manner by the roller 80. Preferably the cog 142 is connected to the rollers 96 by means such as an electric clutch, and operation of the switch 30 thus starts the rollers 96 into operation to lower the sheet 82 to the exposure location or station 56.

Passage of the paper 82 past the switch 102 turns on the charging unit 104 to charge the paper as it passes therethrough. The charging unit 104 turn off shortly after the switch 102 is deactivated. The charge is practically dispelled from the paper in the exposure station 56 in accordance with known principles and the paper then passes through the developer or toner unit 124 for development of the image thereon the paper then being dropped at the copy exit 126, 128.

The specific example of the invention as herein shown and described is for illustrative purpose. Various changes in structure will no doubt occur to those skilled in the art, and will be understood as forming apart of the present invention insofar as they fall within the spirit and scope of the appended claims.

Claims

We claim:

1. A tabletop photocopying machine comprising a housing having a front operating side, a top, a backside and two ends, mean at the top of said housing for receiving an item to be copied and including mean for feeding said item to be copied substantially horizontally relatively from one end toward the other end through said housing and out said other end, an exposure station having a substantially horizontal scanning window within said housing and past which said item is fed in substantially horizontal position means in said housing for illuminating said item at said copying station, a paper safe within said housing adjacent the top thereof for storing a stack of sheets of paper each having a printing face thereon, means in said housing for feeding a sheet of paper from said paper safe substantially horizontally toward said one end of said housing and then substantially vertically down, and exposing station in said housing past which said paper is fed substantially vertically down, an optical system in said housing for projecting an image of said item at said copying station onto the face of said paper at said exposing station, developing means below said exposing station and relatively away from said one end, said developing means comprising, dispensing means for depositing fluid developer on only the face of said paper, a reservoir for liquid developer, and means permitting any excess developer from the dispensing means to fall downwardly for return to said reservoir, thus minimizing the wetting of the surface of said paper opposite said face to which developer is applied, and an exit station adjacent said developing means and below said paper safe, said exit station having paper receiving means within said housing and opening through the front operating side of said housing substantially at right angles to the end through which the item to be copied exits, and feeding means within said housing for feeding said paper down from said exposing station and then substantially horizontally back away from said one end through said developing mean to the paper receiving mean at said exit station.

2. A photocopying machine as set forth in claim 1 and further including a liquid developer in said developing means, and wherein said exit station includes a grid receiving and supporting said paper said grid having open spaces above and below it for drying of both surfaces of said paper.

3. A tabletop photocopying machine as set forth in claim 1 and further including an electrostatic charger within said housing above said exposing station and past which said paper is fed vertically to said exposing station, there being feed roller means above said charger and below said exposing station, but not intermediate said charger and said exposing station.

4. A photocopying machine as set forth in claim 1 wherein said receiving means includes a substantially straight horizontal tunnel through said housing and a downwardly inclined plate leading to said tunnel and on which said item is manually fed to said tunnel.

5. A tabletop photocopying machine as set forth in claim 1 and further including feed roller adjacent said paper safe and engageable with a top sheet of paper in said safe to feed said paper edgewise from a stack thereof in said safe, and further including means for relatively moving said roller and said stack of paper vertically from one another to free said top sheet of paper from said roller as said paper is fed from said paper safe.

6. A part photocopying machine a set forth in claim 1 said reservoir for liquid developer comprising a par of said housing and of shallow height and extending substantially the entire horizontal dimensions of the bottom of said machine.