US3207897A

US3207897A - Apparatus for the thermographic repro-duction of copy from a master

Info

Publication number: US3207897A
Application number: US251909A
Authority: US
Inventors: Limberger Walter
Original assignee: Lumoprint Zindler KG and Co GmbH
Current assignee: Lumoprint Zindler KG and Co GmbH
Priority date: 1962-01-27
Filing date: 1963-01-16
Publication date: 1965-09-21
Anticipated expiration: 1982-09-21
Also published as: GB979740A; DE1421419B2; DE1421419A1

Description

Sept. 21, 1965 w. LIMBERGER 3,207,897

APPARATUS FOR THE THERMOGRAPHIC REPRODUCTION OF COPY FROM A MASTER Filed Jan. 16, 1965 5 Sheets-Sheet 1 /NVENTO,Q WALTER LIMBERGER 5 Sheets-Sheet 2 IIINIQ Mrs/V727, WALTE R LIMBE R6 ER AGENT OF COPY FROM A MASTER Sept. 21, 1965 w LIMBERGER APPARATUS FOR THE THERMOGRAPHIC REPRODUCTION Filed Jan. 16, 1965 Sept. 21, 1965 w. LIMBERGER 3,207,897

APPARATUS FOR THE THERMOGRAPHIC REPRODUCTION OF COPY FROM A MASTER Filed Jan. 16, 1963 5 Sheets-Sheet 3 /NVEN70P WALTER LIMBERGER United States Patent 3,297,897 APPARATUS FQR THE THERMOGRAPHIC REPRO- DUCTIGN 9F CDPY FROM A MASTER Walter Limberger, Hamburg-Poppenbuttei, Germany, as-

signor to Lumoprint Zindler KG., Hamburg, Germany, a corporation Filed Jan. 16, 1963, Ser. No. 251,909 Claims priority, appiication Germany, Jan. 27, 1962, L 41,065 6 Claims. (Cl. 250-65) The present invention relates to an apparatus for transferring copy from a master to a copy sheet with the aid of a coating melting at elevated temperatures.

The application of such a coating to copying material in sheet form is known. In this known process the mass of the coating material is thoroughly melted by the action of heat and transferred to an absorbent or a non-absorbent base. This method is comparatively complicated, because a second sheet of material, namely the base, might be present and brought into surface contact with the copying material. Therefore, it is comparatively complicated to carry out this known process in such manner that it can also be employed for preparing a template or stencil.

It is, furthermore, known to apply the required heat in the form of infra-red radiation. In addition, it is conventional to heat certain surface portions of the copying material at an intensity of which can be selected in accordance with the original copy, by first applying the copying material to the master and then irradiating the superimposed assembly from the side of the copying material. The rays are converted into heat by absorption in colored, particularly black, regions of the original copy, this heat selectively raising the temperature of the copying material. The radiation may also be applied in the form of the aforementioned infra-red radiation, this heat radiation having a temperature which in itself is not suflicient to achieve a reaction but, due to the influence of colored regions on the original copy, sustains an increase in temperature to a level sufficient to initiate the necessary action.

The principal object of the present invention is to provide an apparatus which eliminates these disadvantages and in a preferred embodiment enables an illustration to be transferred to a normal sheet of paper.

According to the present invention, a thermally fusible coating material is selectively melted as a result of the action of radiation, and serves to afiix pigments, capable of producing a contrast coloration, to the copying material along those portions thereof, at which the fusible material is melted, thus resulting in the image.

The melted coating material solidifies after cooling when it has penetrated, at least partly in the liquefied condition, into the surface of the copying material, the portions of the pigment becoming fixed in the surface areas of the copying material. This does not exclude the possibility of the coating material evaporating at least partially upon the action of intense heat.

In accordance with one embodiment of the invention, the coating is provided on the copying material. During, or preferably, after the patchwork melting by the action of heat, a pigment powder is strewn on this coating, adheres to the melted parts and becomes fixed upon solidification of the melted coating, whereupon the excess pigment powder is removed from the other parts of the copying material which have not been in contact with the melted coating.

With a copying material of this type, but preferably with the use of a normal and, if desired, readily absorbent paper as copying material, the meltable coating is provided, in another aspect of the invention, on the particles of a pigment powder. The melting point of this coating is such that, upon contact with the portions of the copying material whose degree of heating depends on the illustration shown on the master, it melts and thereby combines the grains of pigment at these parts with the sheet of copying material as, for example, in that the liquefied coating material permeates the sheet of copying material. This feature has the advantage that the excess pigment powder, which has not been used and is also provided with a coating, can be more easily removed from the portions which are Without legible matter.

To remove the loose pigment powder, a current of air can be used, which at the same time exerts a cooling action on the melted parts and assists their solidifying.

The pigment powder may consist, for example, of solid particles. In accordance with another aspect of the invention, the pigment powder consists of particles of coloring material which dissolves in the coating at a given temperature. This results in good fixing of the image, because this coloring material penetrates into the sheet of copying material with the coating. The use of very small particles of coloring matter ensures sufficient clarity or sharpness of the image.

This method can be carried out by applying the pigment powder after the heat radiation. Preferably, however, it is already strewn on the copying sheet at the time of the heat radiation.

Another feature of the method of the present invention ensures that the coating is arranged on the copying material and the coloring matter is applied by means, for example, of a roller which is guided over the copying material during or directly after the action of the heat rays and to which the coloring material is fed for reaction or bonding only with the coating layer of the copying material in the molten state.

The roller can be preheated in order to maintain a selected temperature differential with full heating being effected by the conversion of the radiation into heat at the legible parts of the original copy. In addition, a roller of a binder can be used in which the coloring substance is embedded. The binding agent is selected such that it is dissolved or melts at a given temperature and releases the coloring material.

With the above described embodiments of the process, a colored illustration results in such a manner that the coloring material is disposed on those portions of the copying material corresponding to the legible parts of the original copy.

An apparatus in accordance with the present invention is preferably provided with a feed mechanism for an original copy and a copying material, a heat source associated with this feed mechanism and a device downstream of the heat source in the feed direction for applying a pigment or coloring material, the feed mechanism being provided for feeding the original copy and the copying material through the region of the radiation source and also past the device for applying a pigment or coloring material. In accordance with the embodiment referred to the feed mechanism consists of a driven cylinder, with which at least one circumferential yoke is associated, at a small space from the cylinder jacket; the latter is stationary and encloses only a part of the cylinder for guiding the copying material, the original copy and co-operates with a clamping hook or claw which is pressed against the cylinder jacket by an abutment edge of its contact arm below the yoke, in order to secure the copying material and the original copy. In a certain position of the cylinder just before the outlet position, the clamping claw is released from the yoke and, due to its pivotal connection and the arrangement of a separating shank, relatively to its center of gravity,

it turns over, whereby the separating shank removes the material from the cylinder jacket and conveys it to a delivery slot. The yoke can be constructed in band or strip form and thus consist of several parallel bands or strips which are preferably perforated downstream of the heat source where a pigment-applying device, such as a heat roller or a driven powder-strewing device, is arranged. When a cylinder with a clamping hook is used, an automatic drive control, by means of a unirotational cam switch is preferably provided, said switch being arranged for example on the shaft of the cylinder and ensuring that the clamping hook is in its operative position, at a point where it can engage the moving edges of the original copy and the copying material.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic side view of an original copy sheet and a sheet copying material on a very magnified scale, in cross-section, to illustrate various methods of pigment application or coloration;

FIGS. 2 and 4 on an enlarged scale to explain a special embodiment of the guide yoke; and

FIG. 7 is a front elevation of the cylinder and yoke assembly according to FIGS. 2 and 4 to explain the arrangement within the apparatus and viewed from the right with reference to FIGS. 2 and 4.

In FIG. 1 an original copy or master 1 having a sheet legible portions 5, 6 and a sheet of copying material 2 having a meltable coating 3 is shown after or during is radiation. This irradiation is effected in the direction of the arrow 4 through the coating 3 and the copying material 2. The master is disposed behind the sheet of copying material on its uncoated side. The radiation is converted into heat at positions 5, 6 (black or colored regions for example) of the original copy, which heat acts through the copying material 2 to melt the coating 3 and produces the melted areas 7, 8 therein, registering and coextensive with the legible portions 5, 6.

The development of the image may be effected in the described manner by the scattering on of pigment powder, as shown on the left of FIG. 1. In accordance with the schematic explanation in FIG. 1, a storage container 9 for receiving the pigment powder 10 is constructed in the form of a hopper with a lower opening 11 in which a roller, for example can run or which can be selectively opened by a slide. This opening extends over the entire width of the copying material 2 with the coating 3; alternatively the latter can be conveyed past below the container 9 or moved the latter over the coating 3 so that the entire coating is uniformly covered with the pigment powder 10.

If melted areas of the coating are present at 7 and 8, the pigment powder is received there by the liquid or pasty coating and/or preferably drawn into the surface of the copying material 2, advantageously upon processing of the layers of copying material and original copy with continuous heating because of the absorbent nature of the said copying material. This results in a well-developed and fixed image.

Another embodiment of the method of the present invention with longer temperature action can also be explained with reference to FIG. 1. In this case the heat developed from the portions and 6 of the original copy 4 causes evaporation or absorption of the coating in the areas 7 and 8 so that these parts are free of coating. Due to the stronger radiation, the coating in this case is melted outside the portions 7, 8 so that, for example the pigment then adheres to these places.

The latter feature, i.e. the removal of the coating from portions 7 and 8 has the advantage that a coating can be used which per se is color-repellent with the result that when dyed with a coloring agent, colour can be absorbed only in the portions 7 and 8- which are free of coating, while the color in other portions is repelled.

The right-hand side of FIG. 1 shows another method of applying coloring matter with the roller 12. The latter is rotatably journalled about a spindle 13 in the direction of the arrow 14, and is resiliently pressed against the coating 3. The coating or the copying material 2 and the original copy 1 are moved, for example, in the direction of the arrow 15, so that the roller 12 turns in the direction of the arrow and feeds coloring matter on its circumference to the coating 3.

This colouring matter is fed from a storage container 16 by means of an absorbent strip 17, for example of felt, which is arranged at one end in the container 16 in which a supply of colouring material 18 is provided and on the other side sweeps over the circumference of the roller 12.

Attention is drawn to the fact that, in a similar manner, a roller could be provided which consists of a binding agent, such as borax, or one of the above mentioned materials which are heat-soluble and in which the coloring matter is embedded, this binding agent being melted by the action of heat. However, it is preferable to provide means for preheating the roller.

FIGS. 2 and 4 show a very suitable and simple embodiment of an apparatus for carrying out the present invention. This apparatus consists practically only of a cylinder or transport drum 19 which forms the feed mechanism, and a device 20 for applying the coloring agents or the portions of pigment, and the sources of radiation 42. The drum 19 is provided in a housing 21 forming enclosure for the drum 19. On the side remote from the device 20, in the front wall 22, above a support table 23 which extends inwardly and outwardly relatively to the front wall 22, the housing 21 has an opening in the form of a feed slot 24 for the copying material and the original or master copy in superimposed relationship. These are introduced in such manner that the copying material lies with its coating downwardly on the table 23 and underlying this, the original copy with the illustration downwardly for example.

A delivery opening 25, preferably in the form of a duct, the lower limiting wall 26 of which extends in the casing into the vicinity of the cylinder 19, is provided above the slot 24.

The cylinder, and, if desired, any other rotating parts, are journaled in side walls 27, 28 (FIG. 7) in the manner shown diagrammatically therein. The side walls are also provided with a stirrup member 29, for example, in the form of a curved plate or several strips or bands, which consist of rigid material, at a small space from the jacket of the cylinder, and surround the cylinder over a portion which begins below the table 23 and terminates above the delivery opening 25. In accordance with FIG. 7, this yoke is provided in the form of a surface 30 which has an opening at 30 through which the color and the pig.- ment can be applied. A corresponding opening 31 is provided in the lower region where the action of radiation takes place. It is pointed out that the opening 31, how-- ever, is barred by wires 32 which extend preferably at an incline relatively to the axis of the cylinder 19, in order to ensure comparatively close contact between the original. copy and the copying material in the area of radiation. For this purpose, a special embodiment may be provided which will be described hereinafter with. reference to FIG. 6.

The casing 21 has a substantially horizontal base plate 33 on which there is arranged, beneath the inner end of the table 23, a motor 34 drives the cylinder 19 by way of a round belt 35, from which cylinder, as shown in FIG. 4, a delivery roller 47 for pigment powder can be driven by way of a round belt 36. Adjacent to the motor, a chamber 38, open at the top and defined by side walls, is constructed on the bottom of the casing, the

end walls

39, 40 of said chamber terminating near the stirrup member 29 while the side walls 41 thereof, corresponding to the shape of the stirrup member 29, have an arcuate edge. Heat radiators, e.g. infra-red radiators 42, are provided in the chamber 38 and constitute heating means forwardly of the pigment-transfer means etc. It is possible to direct the rays towards the cylinder by reflectors. In this connection it is pointed out that opening 31 extends over the region of the chamber between the

end walls

39, 40 and the side walls 41, only one of which is shown. This makes it possible for the rays to immediately reach the layers consisting of the copying material and the original copy.

The embodiments shown in FIGS. 2 and 4 have the additional common feature that the two ends of the cylinder 19 are provided with hook-shaped clamping means constituted by pivotable clamping hooks or claws 43, this feature being shown in broken lines in another position at 43'.

It is important that the circumferential yoke should extend, when the cylinder is rotated counter-clockwise, from a point to the left of the lowest point of the cylinder, the opening 31 being in front of the lower part of the cylinder. The yoke ends approximately at a point just above the horizontal line through the axis of the cylinder. The clamping hook is a preferred embodiment of the clamping means.

FIG. 7 shows that two clamping hooks 43, 44 are provided. These are located mainly in

recesses

80, 81 which are opened towards the periphery and the ends of the cylinder 19. The object of this is that one part, lying as far as possible outside the ends, i.e. the pressure shank 45, which will be described hereinafter, should extend into an area where it is always guided by the stirrup member 29, preferably also outside the

opening

30, 31, whilst a separating shank 46, which has still to be described, can actually operate on the edge of the materials resting against the cylinder 19. A contact edge 47 of shank 45, which will be described hereinafter, engages across the

recesses

80, 81 and preferably extends through a closed jacket portion of the cylinder 19. The arrangement of two clamping hooks has the advantage that the layers of material are aligned relatively to the axis of the cylinder.

Owing to the action of control means, which will be described hereinafter, the clamping hooks 43 are in the starting position at the point shown in FIGS. 2 and 4, the mouth of the hook facing the inner edge of the supporting table 23. In this connection it is pointed out that the clamping hooks represent an extremely simple and efficient device in the preferred arrangement of the radiation sources sources 42 in the lower region of the apparatus, as thanks to their special design control of the hook adjustment is achieved by peristaltic action.

It is apparent that the clamping hooks 43 have two shanks, namely a pressure shank 45 and a separating shank 46 which, as shown, are directed towards each other in order to achieve a specific distribution of the weight. A contact edge 47, extending preferably beyond the width of the

recesses

80, 81 and always outside the cylinder 19, is formed on the pressure shank 45. A pivot pin 48 is provided practically within the axial extension of the separating shank 46. The main mass of the clamping hook is located at the side of the pressure shank 45, however the separating shank 46 is much longer, for example twice as long, than the pressure shank 45.

Owing to the above described arrangement of the

recesses

80, 81, the pressure shank 45 and the separating shank 46 are relatively displaced in the axial direction of the cylinder 19, in such manner that the pressure shank 45 lies outside and the separating shank 46 inside the cylinder. The contact edge 47 engages through the recesses for the clamping hooks.

Because of its weight, the clamping hook 43 assumes the position shown in FIGS. 2 and 4 which is limited by a stop 49 on the cylinder jacket. It is apparent that the assembly of copying material and original copy is inserted into the mouth of the clamping hook. When the cylinder 19 is driven in the direction of the arrow 50, the clamping hook moves into the circumferential yoke 29, whereby it is pressed into the position which still exists at 43. At the same time the contact edge 47 urges the front edges of the copying material and the original copy against the cylinder 19 with the result that the latter can perfectly engage these materials.

When the clamping hook 43 leaves the area of the yoke 29, as shown in FIG. 3, the clamping hook drops or springs into the position 43 in which the separating shank 46 extends beyond the circumference of the cylinder 19 and spreads apart the front edges of the original copy and the copying material so that they are raised over the limit ing wall 26 into the delivery opening 25. This spreading action on the part of the separating shank 46 is a result of the weight distribution; however, it is obvious that for this purpose a spring can be provided between the pivot pins 48 and the clamping hook 43, as shown by 51 in FIG. 7.

From FIGS. 2 and 4 it is apparent that, in accordance with a preferable conformation near the upper end of the stirrup 29, a further recess 52, small, if desired, is formed through which a roller 53 acts on the circumference of the cylinder 19. This roller is freely rotatable on a spindle 54 which in turn is pivotably mounted on casing 21 by means of a spring 55. The spring is adjusted so that the roller 53 is urged against the casing of the cylinder 19 to afford accurate guidance of the copying material and the original copy as long as the cylinder 19 is being moved from the position in which the clamping hooks are at 43' to the position reached by the clamping hooks 43. This path is so designed that the passing edges of the original copy and the copying material can issue from the delivery opening 25 and can be engaged.

The apparatus can be controlled as follows. The motor circuit 35 is connected to the mains supply or a current source 56. Two switches are provided in series in this circuit, i.e., a push button switch 47 for switching on and a switch 58 which is normally opened against spring force and can be opened in a specific position of the motor by a cam 59 mounted on the motor shaft 89. The arrangement of the cam 59 on the motor shaft 89 or the output shaft of the motor drive unit is shown diagrammatically only. In practice the cam is arranged on the shaft of the cylinder 19 so that it rotates synchronously therewith. The push button switch 57 is bridged by the self-holding contact 61 of the relay 60 in whose energizing circuit the switch 58 is also disposed. The cam 59 is disposed preferably in a one-way coupling ensuring that the cylinder 19 executes only one complete rotation; however, the brake mechanism or holding device for the motor is so offset that the switch 58, whose opening initiates the conclusion of the rotation and interrupts the exciter circuit for the relay 60, and after the opening of the self-holding contact 61 and with the motor fully stopped, i.e. after retarding the rotating masses, is closed again so that the position of readiness is reached.

FIG. 5 shows a simple embodiment. The motor 35 drives a cam disc 82 in the direction of the arrow, by way of a reduction gear, in such manner that the disc always executes only one rotation. The cam 59 is mounted on this disc and is provided with a lock 83 coupled e.g., by way of a swivel rod system 84, with the operating pushbutton switch 57, in such manner that, when the switch is operated, it is raised from the path of the cam 59.

The motor can then freely start until, just before the concal actuating member 85 near the path of movement of the cam 59, whereby the motor, the driven and other attached parts are switched off.

The motor, the cam disc and the driven parts continue to run, owing to inertia, until the cam 59 is retarded by the lock 83 which, on account of the spring 86 of the push button switch 87, has been brought into the path of the cam 59 after the switch 57 is released. The switch 58 is normally kept in the closed position by the spring 57.

The push-button switch 57 can be operated by hand after the insertion of the copying material and the master or in any known manner, or, preferably, with the interposition of a retarding member, by the very insertion of the master and the copying material, as is known. The motor 35 drives the cylinder 19 in the already described manner and, if desired, a roller 62 in the device 20 for applying the colour of the pigment.

In a simple embodiment according to FIG. 2, this device consists of a trough 63 in which a supply of coloring matter or coloring composition 64 is provided. The roller 65 is rotatably journaled above this trough in the side wallls of the casing. The roller has a jacket of absorbent, resilient, if desired, profiled material. The method of mounting is such that the bearing blocks, in which the shaft 66 of the roller 65 is journaled, can be displaced in a slot 67 in the side wall of the apparatus. This slot extends radially to the cylinder 19. Within this slot the bearing block is urged by a spring 68 against the cylinder 19.

It may be seen that such a bearing arrangement is provided at each end of the roller 65. It may also be seen that, in this construction, no special drive is required for the roller 65.

The cylinder 19 is designed in such manner that the copying materials are free of the roller 65 when the cylinder 19 stops, i.e. the clamping hook 43 is disposed at the point indicated by full lines.

It is also apparent that the coloring material is applied directly after the action of heat, by the device 20, shown in FIG. 2, with the roller 65, and that the path consisting of the periphery 19 and the distance to the delivery opening 25 is long enough for the materials to solidify and thus to fix the image. The roller 65 extends through the opening 30 (FIG. 7). In accordance with FIG. 4 a roller 69 for pigment powder 70 is provided near the opening 30 (FIG. 4), said powder being stored in a container accessible from the outside and closed by a cover 72. This container forms a base wall inclined relatively to the cylinder 19 and terminating near the circumfer-- ential stirrup member 29 approximately in the center of the opening 30. Disposed above the base wall 73 is a delivery opening 74 in which the driven applicator roller 69 rotates in clockwise direction. This roller closes the slot almost completely. Advantageously, a small clearance is left below the roller, small enough to prevent the automatic issue of the pigment powder. The roller is preferably provided with profiled portions, if desired in the form of longitudinal grooves or dish-shaped depressions, by which pigment powder is received. By applying a high circumferential speed to the roller 69, the pigment powder is centrifuged against the coupling material as it passes the opening 30 and fixed on the melted portions. Excess pigment powder falls into a receiving trough 75 provided below the opening 30.

In order to achieve correct surface pressure, it is possible, as shown in FIG. 6 to make the lower portion of the yoke 29 pivotal by means of a link 78 and to press it against the cylinder by a spring 76. The stirrup member is provided with plotlike openings in its pivotable portions 77, i.e. it is constructed as a slotted plate through which the heat radiation can act directly and uniformly on all portions of the surface of the copying material. Such a pressure plate is described for example in patent application No. 31,773/ 60 (U.S. patent application Serial No. 53,539 now U.S. Patent No. 3,101,034). It is pointed out that in the present case it is preferable to construct the pivotable portion 77 of the stirrup member 29 in the form of the slotted plate of a material having a low heat capacity and reduced conductivity i.e. preferably of plastic material.

For guiding the clamping hooks 43, the pivotable portion 77 has downwardly curved duct-like guides 79 which are open at the top and whose base is disposed at a distance from the peripheral of the cylinder 19 which corresponds substantially to the other spaced relationship of the stirrup member 29 relative to the cylinder 19.

We claim:

1. Apparatus for the reproduction of copy from a master comprising:

housing means forming an enclosure provided with at least one opening for the insertion and removal of a copy sheet and a master sheet;

a transport drum journaled in said enclosure and angularly displaceable therein for transporting said sheets jointly in superposed relationship from said opening along a reproduction-development path and subsequently discharging said sheets from said enclosure, said copy sheet being adapted to receive a pigment for the development of an image thereon at portions of said copy sheet of an elevated temperature sufiicient to thermally fuse a substance for fixing said pigment to said copy sheet upon cooling of said substance;

heating means along said path for bringing said copy sheet at least to said temperature at regions of said copy sheet corresponding to legible portions of said master sheet;

pigment-transfer means forwardly along said path of said heating means and angularly offset therefrom in the direction of rotation of said drum for transporting pigment to the heated regions of said copy sheet;

a stirrup member peripherally surrounding said drum in closely spaced relationship therewith over an arc corresponding to at least a portion of said path commencing rearwardly of said heating means and extending to a location of said path at which said sheets are discharged from said enclosure;

and hook-shaped clamping means on the periphery of said drum engageable with said sheets rearwardly of said heating means and held thereagainst by said stirrup member for entraining said sheets with said drum along said path with said master sheet adjacent said drum and said copy sheet adjacent said master sheet and said stirrup member, said stirrup member being at least partly open in the region of said heating means and said pigment-transfer means while maintaining said clamping means in engagement with said drum.

2. An apparatus as defined in claim 1 wherein said drum is substantially cylindrical and has a generally horizontal axis, said enclosure being provided with a first elongated opening and a second elongated opening spaced therefrom, said openings extending generally parallel to said axis and constituting respectively an inlet and an outlet for said sheets, said inlet being disposed below said outlet, said heating means being disposed in said enclosure below said inlet, said stirrup member defining with said drum an arcuate channel centered on said axis and commencing intermediate said inlet and said heating means.

3. An apparatus as defined in claim 2 wherein said outlet is angularly spaced above said inlet by a minor fraction of the angular rotation of said drum and said stirrup member extends over a major portion of the circumference of said drum from said inlet substantially to said outlet.

4. An apparatus as defined in claim 2 wherein said clamping means comprises at least one double-armed lever pivoted on the periphery of said drum about an axis parallel to the axis of rotation thereof, said lever having a first relatively short claw-shaped arm projecting outwardly beyond said periphery for engagement with said sheets and a relatively long arm overlying said periphery for diverting said sheets toward said outlet at the end of said stirrup member in the direction of rotation of said drum.

5. An apparatus as defined in claim 4 wherein said stirrup member has an apertured swingable portion of reduced heat capacity and thermoconductivity bearing upon the sheets carried by the periphery of said drum in the region of said heating means.

6. An apparatus as defined in claim 1 wherein said stirrup member includes a plurality of circumferentially extending arcuate bands closely juxtaposed with the periphery of said drum.

References Cited by the Examiner UNITED STATES PATENTS 2,503,758 4/50 Murray 250-65 2,503,759 4/50 Murray.

2,552,209 5/51 Murray 11717.5 2,844,733 7/58 Miller et a1. 250-65 2,855,324 10/58 Van Dorn 117l7.5 2,903,546 9/59 OMara 25065 3,081,699 3/63 Gulko 25065 RALPH G. NILSON, Primary Examiner.

Claims

1. APPARATUS FOR THE REPRODUCTION OF COPY FROM A MASTER COMPRISING: HOUSING MEANS FORMING AN ENCLOSURE PROVIDED WITH AT LEAST ONE OPENING FOR THE INSRTION AND REMOVAL OF A COPY SHEET AND A MASTER SHEET; A TRANSPORT DRUM JOURNALED IN SAID ENCLOSURE AND ANGULARLY DISPLACEABLE THEREIN FOR TRANSPORTING SAID SHEETS JOINTLY IN SUPERPOSED RELATIONSHIP FROM SAID OPENING ALONG A REPRODUCTION-DEVELOPMENT PATH AND SUBSEQUENTLY DISCHARGING SAID SHEETS FROM SAID ENCLOSURE, SAID COPY SHEET BEING ADAPTED TO RECEIVE A PIGMENT FOR THE DEVELOPMENT OF AN IMAGE THEREON AT PORTIONS OF SAID COPY SHEET OF AN ELEVATED TEMPERATURE SUFFICIENT TO THERMALLY FUSE A SUBSTANCE FOR FIXING SIAD PIGMENT TO SAID COPY SHEET UPON COOLING OF SAID SUBSTANCE; HEATING MEANS ALONG SAID PATH FOR BRINGING SAID COPY SHEET AT LEAST TO SAID TEMPERATURE AT REGIONSL OF SAID COPY SHEET CORRESPONDING TO LEGIBLE PORTIONS OF SAID MASTER SHEET; PIGMENT-TRANSFER MEANS FORWARDLY ALONG SAID PATH OF SAID HEATING MEANS AND ANGULARLY OFFSET THEREFROM IN THE DIRECTION OF ROTATION OF SAID DRUM FOR TRANSPORTING PIGMENT TO THE HEATED REGIONS OF SAID COPY SHEET; A STIRRUP MEMBER PERIPHERALLY SURROUNDING SAID DRUM IN CLOSELY SPACED RELATIONSHIP THEREWITH OVER AN ARC CORRESPONDING TO AT LEAST A PORTION OF SAID PATH COMMENCING REARWARDLY OF SAID HEATING MEANS AND EXTENDING TO A LOCATION OF SAID PATH AT WHICH SAID SHEETS ARE DISCHARGED FROM SAID ENCLOSURE; AND HOOK-SHAPED CLAMPING MEANS ON THE PERIPHERY OF SAID DRUM ENGAGEABLE WITH SAID SHEETS REARWARDLY OF SAID HEATING MEANS AND HELD THEREAGAINST BY SAID STIRRUP MEMBER FOR ENTRAINING SAID SHEETS WITH SAID DRUM ALONG SAID PATH WITH SAID MASTER SHEET ADJACENT SAID RUM AND SAID COPY SHEET AJACENT SAID MASTER SHEET AND SAID STIRRUP MEMBER, SAID STIRRUPMEMBER BEING AT LEAST PARTLY OPENIN THE REGION OF SAID HEATING MEANS AND SAID PIGMENT-TRANSFER MEANS WHILE MAINTAINING SAID CLAMPING MEANS IN ENGAGEMENT WITH SAID DRUM.