GB2170150A - Stencil duplicator with integral stencil imager - Google Patents

Abstract

A stencil duplicator with integral stencil imager 12 has a stencil loading guide 18 as a downwardly extending chute in which the leading edge of the stencil 7 is inserted ready for automatic stencil loading, and an original placed on the stencil and irradiated by operation of a thermal flash lamp 13 will, upon loading of the stencil onto the stencil mounting means 5 of the duplicator, be entrained, solely by the action of adhesion tendency between the original and the stencil in the image area thereof, for leftward movement in a substantially planar original-delivery path from which the downwardly moving stencil 7 diverges. <IMAGE>

Description

SPECIFICATION Stencil duplicator with integral stencil imager The present invention relates to a stencil duplicator incorporating an integral stencil imager, and provides for simple operation of the task of loading a stencil which has just been imparted with its image defined by ink-permeable "image areas" and inkimpervious "background areas" by an imaging technique involving radiation in conjunction with an image-bearing original.

US Patent No. 3,788,221 (BORNEMAN) and Japanese Patent Application (Kokai) 59-7082 (MAT SUSHITA) both disclose stencil duplicators incorporating stencil imaging systems using irradiation of the stencil, in conjunction with an imagebearing original, using thermal radiation.

In US Patent No. 3,788,221, the stencil material is roll fed and separation of the original from the stencil material requires passing the original round a suction roller 230 while the leading edge of the stencil is in the field of influence of a suction clamp 39 of the duplicator cylinder. The need to supply suction involves an unnecessary complication of the duplicator, and can give rise to increased power consumption.

Japanese Kokai 59-7082 discloses an automatic stencil separating mechanism to remove the original from the stencil, using a deflector plate which is optionally moved into the path of the stencil and original.

It is an object of the present invention to provide a simplified form of separating mechanism for the stencil and original.

Accordingly, the present invention provides a stencil duplicator including integral stencil imaging means in which the stencil and an original are irradiated while in contact with one another to impart ink pervious areas of the stencil to correspond to dark image areas of the original; an original delivery location for an original after imaging of a stencil therewith; an original delivery path from the stencil imaging means to the original delivery location; and a stencil loading path divergent from said original delivery path and extending towards the duplicator cylinder, there being no original feed means to advance the original along the substantially planar original delivery path, such feed being effected by adhesion tendency between the original and the stencil before arrival at the point of separation of the stencil loading path from the original delivery path.

In order that the present invention may more readily be understood the following description is given, merely by way of example, with reference to the accompanying drawing in which a single embodiment of a duplicator and integral stencil imager in accordance with the present invention is illustrated in schematic form.

The combined apparatus 1 shown in the drawings comprises a stencil duplicator section having an upper cylinder 2 and a lower cylinder 3 with an ink screen 4 mounted thereon, the ink screen further including a mounting bar for a stencil heading strip and including mounting studs 5 to engage perforations in the heading strip.

An inker 6 deposits the required amount of ink on the external surface of the lower cylinder 3 and this ink is then able to pass outwardly through the ink-pervious ink screen 4 and to penetrate the inkpervious image areas of a stencil 7, in use of the duplicator, so as to be transferred onto a copy sheet from a sheet feeder 8, by virtue of the squeezing action of an impression roller 9 (driven for vertical) movement in the conventional manner in response to the presence of a sheet in the nip).

The printed copy sheets are delivered as a stack 10 on a sheet receiving tray 11.

The apparatus further includes a stencil imaging section generally designated 12, comprising a thermal radiation- emitting lamp 13 under a platen cover 14 which holds an original and the stencil 7 in intimate contact with one another, under a predetermined pressure, during imaging. The imaging lamp 13 may, for example, be caused to traverse horizontally from the position shown in the drawings, to the righthand end of the imaging section 12, and is preferably a flash lamp, for example a Xenon flash lamp, to impart the desired heat to the pigment in the image areas of the original causing those image areas to heat up and to convert the corresponding areas of the stencil to ink-pervious condition. The rate of flashing of the lamp will be controlled in relation to the rate of scanning so that the entire length of the stencil will be imaged without discontinuity.

The platen cover 14 is manually lowered onto the assembly of stencil and original and the operation of the lamp is either manually effected after covering of the platen, or automatically initiated by the closing action.

The imaging section 12 is horizontally along-side an original-collecting tray 15 on which originals which have already been imaged are received, as will be described below.

The duplicator further includes a stencil disposal means, in this case comprising a container 16 in conjunction with a pair of stencil-advancing toothed wheels 17 to drive an ejected stencil from the ink screen 4 and stencil mounting studs 5 into the container 16, as described in our British Patent No. 1,502,522.

It is important to note that the stencil 7 is shown in the drawing as being guided down a relatively steep chute 18 towards the mounting pins 5 of the stencil mounting bar. The chute 18 thus forms a stencil loading guide and may, for example, be of the type disclosed and claimed in our British Patent No. 1,560,153.

In order to load the imaging section 12, a thermally sensitive stencil is first of all introduced with its leading edge in the chute 7, where it will be held in position ready to be lowered into the path of movement of the studs 5 at some later convenient time in the operating cycle of the stencil duplicator part of the apparatus. The rest of the stencil is then pressed manually flat onto a glass plate 19 of the imaging section and an original is placed, face down, on the stencil, conveniently positioned where it is within the confines of the glass plate 19 and overlies a part of the stencil to be imaged.

Then the platen cover 14 is lowered and stencil imaging takes place.

During the above described operations, the duplicator cylinders 2 and 3 may still be rotating and sheets may be fed by the sheet feeder 8 to print copies of the previous stencil.

When the desired number of copies from the previous stencil has been printed, the duplicator is operated to eject the used stencil into the container 16 by way of the toothed wheels 17 and then, as the studs 5 next approach the chute 18, the leading edge of the now imaged stencil 7 is dropped into the path of action of the studs 5 to allow them to entrain the stencil and to draw it down the chute 7.

During this action, the sharp downward deflection of the stencil 7 will be possible while leading edge of the original passes horizontally leftwardly towards the original-collecting tray 15. This is because at the top edge of the original there is unlikely to be any image and consequently there will have been no heat causing a tendency of the original to stick to the stencil.

Once this initial separation, by virtue of the sharp edge 20 at the righthand end of the originalreceiving tray 15, has been effected, further anticlockwise rotation of the ink screen 4 and the stencil mounting bar with its studs 5 will draw the remainder of the stencil onto the ink screen and, in so doing, the tendency of the image areas of the original and the image areas of the stencil to adhere to one another, by virtue of the heat modification of the plastics material of the stencil in the "image areas", will urge the original for further leftward movement until eventually the original is fully positioned on the original-receiving tray 15 and the stencil is completely loaded on the ink screen and is being inked by virtue of the layer of ink applied by the inker 6 to the lower cylinder 3.

If desired, a particularly long original may be laid on the glass plate 19 so that one end overlies the end of the plate and may even be positioned above the separating edge 20 of the original-receiving tray 15. However, it is envisaged that the separating edge 20 can operate successfully even where the leading edge of the original is to the right of the edge 20.

The above described apparatus can be modified in various ways, for example the actual stencil loading system may be different and may not need the stiff heading strip of the stencil to be engaged by studs 5, but instead some other system, for example a clamp, preferably a mechanical clamp, may be used. Likewise. the stencil-ejecting means may be of some alternative form other than the container 16 and toothed wheels 17.

Similarly, other forms of imaging system may be provided, and for example the scanning flash lamp 13 may be repiaced by a stationary lamp, for example a flash lamp positioned just bellow an upper roller (not shown) which will smooth the original and stencil together during imaging and will avoid the need for the platen cover 14.

Although the embodiment shown in the drawings and described above uses discrete sheets of stencil material, the present invention can equally well be applied to a continuous web of stencil material, for example advanced from a supply roll.

Claims (9)

1. A stencil duplicator including: integral stencil imaging means in which the stencil and an original are irradiated while in contact with one another to impart ink pervious areas of the stencil to correspond to dark image areas of the original; an original delivery location for an original after imaging of a stencil therewith; an original delivery path from the stencil imaging means to the original delivery location; and a stencil loading path divergent from said original delivery path and extending towards the duplicator cylinder, there being no original feed means to advance the original alor.g the substantially planar original delivery path, such feed being effected by adhesion tendency between the original and the stencil before arrival at the point of separation of the stencil loading path from the original delivery path.

2. A stencil duplicator according to claim 1, wherein the imaging section is immediately above the level of a stencil loading means of the duplicator whereby the stencil is deflected downwardly from the original delivery path.

3. A stencil duplicator according to either of the preceding claims, and including a sharp deflector guide between the stencil loading path and the original delivery path at the point of separation of those paths.

4. A stencil duplicator according to any one of the preceding claims, wherein the stencil imaging means comprises means for irradiating the stencil and an original with thermal radiation.

5. A stencil duplicator according to claim 4, wherein the thermal radiation emitting means comprise a Xenon flash lamp.

6. A stencil duplicator according to claim 4 or 5, wherein the stencil irradiation means are mounted for horizontal movement to irradiate a stationary assembly of superposed stencil and original.

7. A stencil duplicator according to any one of the preceding claims, and including means for automatically ejecting an inked stencil from the duplicator cylinder and for receiving it ready for disposal.

8. A stencil duplicator according to any one of the preceding claims, wherein the stencil imaging means inciude a transparent platen and a manually movable platen cover to press the superposed stencil and original onto the platen, and including means for automatically initiating operation of the stencil radiating means on arrival of the platen cover at a closed position on the platen.

9. A stencil duplicator with integral stencil imager, substantially as hereinbefore described with reference to and as illustrated in the accompany drawing.