US3232226A

US3232226A - Printing apparatus

Info

Publication number: US3232226A
Application number: US212045A
Authority: US
Inventors: Schaum Gustav; Haydn Hildegard; Moller Rudolf; Schott Walter; Fritsch Franz
Original assignee: Agfa AG
Current assignee: Agfa Gevaert NV
Priority date: 1960-11-16
Filing date: 1962-07-24
Publication date: 1966-02-01
Anticipated expiration: 1983-02-01
Also published as: DE1422992A1; GB952964A; US3250616A; GB969172A; DE1622742A1; GB951987A; GB950007A; CH398650A; DE1622742B2; BE634190A; BE634189A; CH435332A; CH409633A; BE630995A

Description

Feb. 1, 1966 G. scHAuM r-:TAL 3,232,226

PRINTING APPARATUS Filed July 24, 1962 2 Sheets-Sheet 1 1N V EN TOR.

GUSTAV SCHAUM BY HILDEGARDHAYDN RUDOLF MULLER WALTER SCHOTT FRANZ FRITSCH Feb. 1, 1966 s. scHAuM ETAL 3,232,226

n PRINTING APPARATUS Filed July 24, 1962 2 Sheets-sheet z RUDOLF MULLER WALTER SCHOTT FRANZ PRITSCH United States Patent 3,232,226 PRlTNG APPARATUS Gustav Schaum and Hildegard Haydn, Leverkusen, Rudolf Muller, Grunwald, near Munich, and Walter Schott and Franz Fritsch, Munich, Germany, assignors to Agfa Aktiengesellschaft, Leverkusen-layerwerk, Germany, a corporation of Germany Filied luiy 24, 1962, Ser. No. 212,045 Claims priority, application Germany, .luly 29, 1961, A 38,014 14 Claims. (Cl. lill- 132) This invention relates to an apparatus for printing multiple copies from a master sheet, and it particularly relates to such an .apparatus utilizing a master sheet incorporating a printing substance which transforms to a fluid such a-s rvby melting or sublim-in g when heat is applied to it.

Copending, commonly assigned application Serial No. 150,641, tiled November 7, 1961, describes and claims a process for print-ing multiple copies from a master sheet incorporating dyestuffs or printing substances which are capable of easily melting or subliming. Such a master sheet can be photographically prepared, or by a more simple impression from a sheet of copying material. In the latter method a sheet of copying ma-terial incorporating printing substances which are transformed to a ilu-id by being melted or sublimated by application `of heat, is laid upon the surface of a sheet of any type of paper preferably of relatively slight thickness; and an inscription is then impressed upon the paper and against the copying material behind it, by hand or typewriter. This transfers some or all of the printing substance from the copying material to the back o-f the inscribed paper as a mirror image of the applied inscription.

The master sheet thus obtained is -t-hen contacted with ordinary paper, such as typewriting paper, and heat is briefly applied to them to trans-fer part of the printing substance upon the master sheet by melting ori sublimation to the ordinary paper which is thereby im-p-rintetgl.` This process can be repeated up to at least fifty times from a lsingle master sheet without unduly diminishing the quality of the print, and under certain circumstances even up to one hundred and fifty copies can be printed from a single master.

An object of this invention is to provide an apparatus for printing multiple copies from a master sheet incorporating a printing substance which melts or suhlimates when heat is applied to it.

In accordance with this invention a heat-affected master printing sheet is secured upon a rotating cylinder which is heated from within. A pressing device is mounted 4in contact with the heated surface of the cylinder for maintaining sheets `of paper to be printed .in contact with the master sheet. rI`his pressing device includes a movable surface for engaging the paper in steady contact relative to the rotating surface o-f the cylinder, and this device is also preferably heated. The tubular surface of the cylinder is heated to a temperature ranging approximately from 160-220 C. and preferably ranging approximately from 170-l90 C. The pressing device may advantageously include a pressure roller, which is also heated from within to a temperature ranging approximately from 12.0 -l80 C. The cylinder and pressure roller may advantageously be rotatably mounted upon hollow shafts thro-ugh which lines for supplying power to heat them may pass.

In a particularly efficient form of this invention a number of strip heaters are mounted longitudinally within the cylinder concentrically about its axis of rotation for uniformly heating its surface.

Concave reflectors are preferably mounted longitudinally between the strip heaters and the axisl of rotation of the cylinder Afor directing the heat radially outwardly, and

ICC

these concave reflectors may be incorpo-rated in a unitary tube having a series of longitudinal concave indentations. This unitary reflector directs a maximum amount of the heat radiating from the heaters radially outwardly toward the surface of the cylinder. The strip heaters are supported between a pair of flanges mounted within the cylinder, which are made of a heat resistant material, such as a heat insulating material. Ceramics have proved very effective for these end supporting flanges which reset and combine the heat emanating from the strip heaters.

The amount of pressure between the pressing device and the cylinder is not very Vcritical in providing clear yand distinct copies. However it is important to extend the time that the paper is maintained in heated contact with the master sheet. Several additional pressure rollers 'are therefore connected in back of the initial heated pressure roller, `and these additional rollers are preferably unheated. The paper being printed is therefore heated very quickly up to printing temperature as it passes under the heated pressure roller, and it maintains the transfer temperature without substantial change as long as it is maintained in contact with the heated surface of the printing cylinder.

The printing quality is even more improved by utilizing an endless belt in the pressing device which conforms closely tothe surface of the cylinder. Such an endless belt assures complete and intimate contact of the paper with the master sheet throughout its entire arc of contact with the cylinder. An endless belt of this type is preferably mounted between a heated press roller or pulley and `an unheated return pulley. The return pulley is resiliently urged away from the heated pressure pulley and toward the cylinder for stretching the belt between them in firm contact with the heated surface of the cylinder and the master .sheet mounted upon it.

The stuface of the cylinder is preferably made of an elastic material such as silicone rubber, and a steel endless belt is advantageously utilized with such 'an elastic surfaced cylinder. In another form of vthis invention the sur- -face of the cylinder is made of metal, and the endless belt is made of a synthetic or textile fabric. The same combination of materials may also be utilized in the form of this invention incorporating pressure rollers instead of an endless belt.

The pressing device or assembly -is preferably mounted upon a rotatable lever, which is .actuated by a manuallyoperated cam and follower to move it toward and -away from the cylinder `for changing master sheets.

Novel features and advantages of the present invention will become apparent to one skilled `in the art from a reading 4of the following description in conjunction with the accompanying drawings wherein similar reference characters refer to similar parts and in which:

FIG. 1 is a schematic side view in elevation of a portion of one embodiment of this invention;

FIG. 2 is a cross-sectional View taken through FIG. 1 along the line ll-Ih and FIG. 3 is a schematic side view in elevation of a portion of a modified form of the invention shown in FIG. 1 with an end wall of the printing cylinder removed.

In FIG. l is shown a printing apparatus 1 with a bracket 2 mounting an infinitely variable transmission 3 upon it. An electric motor 4 is connected to drive transmission 3. A control knob 5 adjusts the speed of drive shaftV 6, which ultimately rotates pulley 9 connected to cylinder lit through drive pulley 7 and belt 8. A chain and sprocket drive may also be used instead of the pulley and belt drive.

Sheets of paper to be printed are positioned upon feeding table 1i and received by rear table 12 after passing in contact with the surface printing cylinder l0. A feeding roller f4 rests upon paper stack 13 on table 11, and

, it isconnected through a one-way clutch (not shown) with shaft of feeding lever 16 to cause roller 14 to rotate freely across paper stack 13 when it moves toward the left as shown in FIG. 1. When roller 14 moves toward the right, it does not rotate which causes it to push the top paper sheet on stack 13 over tongue 11a of table 11 between

feed rollers

17 and 18 whose operation is later described in detail.

Feeding lever 16 is rotatably connected by pin 19 to the top of double-ended link 20 which is rotatably mounted upon shaft 21 secured to the frame of apparatus 1. The lower end of the link 20 is rotatably connected by pin 22 to one end of connectingy rod 23 Whose other end is rotatably connected through pin 24 with `angular link 25, which is rotatably mounted upon shaft 26 secured to the'frame of apparatus 1. Upon other end of angular link is mounted a follower roller 27 which engages the surface of cam disc 2S which is secured to rotate together with pulley 9 and printing cylinder 10 about the same axis of rotation. Follower roller 2'7 is maintained engaged with cam 28 by spring 29 reacting betwen the lower end of link 20 and the frame of apparatus 1. A second cam 30 is secured to rotate together with pulley 9 and a cam 2S, and another follower roller 31 engages the surface of cam 30. Roller 31 is mounted upon a radial arm 33 connected to geared sector 34, and ar-m 33 is rotatably mounted about pin 32 with geared sector 34 in meshing engagement with gear 35 which in turn meshes with gear 36 which is connected through a one-way clutch (not shown) to drive feed roller 17. Spring 37 reacting between radial arm 33 and the frame of the apparatus maintains follower roller 31 in engagement with cam 30. The surfaces 17a and 18a of

feed rollers

17 and 18 are lmade of an elastic material such as rubber.

When pulley 9 is rotated clockwise from the position shown in FIG. l, roller 14 is first moved toward the left whereby it freely rolls across the top of paper stack 13. Radial arm 33 connected to geared sector 34 moves clockwise toward the right during most of this recovery phase of operation, and it thus causes gear 35 to rotate gear 36 clockwise. The one-way clutch (not shown) between gear 36 and roller 17 prevents roller 17 from being rotated in the clockwise phase of rotation of gear 36.

After roller 14 reaches its extreme left position and starts to move toward the right, its one-way clutch prevents it from rotating, and it then pushes the top sheet on paper stack 13 toward

feed rollers

17 and 18. Before the front edge of the sheet of paper reaches

rollers

17 and 18, the direction of rotation of radial arm 33 connected to geared sector 34 is reversed to the counterclockwise direction thereby causing roller 17 to also rotate counterclockwise through the one-way clutch (not shown) which transmits only counterclockwise rotation from gear 36 to rollers 17 which together with induced rotation of feed roller 18 feeds the paper positively toward the surface of printing cylinder 10.

As shown in FIG. 2, cylinder 10 includes a tube 38 whose ends are closed by walls or

flanges

39 and 40 having

hollow shafts

41 and 42 extending outwardly from them. Pulley 9 and cams 2S and 30 are secured to

shafts

41 and 42.

Shafts

41 and 42 are rotatably mounted within roller bearings 43 secured within side walls 44 of the frame of apparatus 1. Caps 45 cover the outer ends of bearings 43, and a tubular conduit 46 extends through the axis of rotation of cylinder 10 and bearings 43 for conducting electrical p-ower supply leads 47 within cylinder 10. Electrical leads 47 are connected to electric strip heating elements 48. Heating elements 48 are longitudinally mounted concentrically within cylinder 10 between supporting flanges 49, and are preferably made of a heat resistant and insulating material such `as a ceramic material.

FIG. 3 illustrates how concave reflectors 50 are mounted betwen strip heaters 48 and the axis of rotation of cylinder 10 for directing their heat radially outwardly. Reflectors 50 are advantageously formed by longitudinal concave indentations in the surface of a substantially closed tube 51 whose inner surface is painted black for example by a Varnish. This causes practically the entire heat output of strip heaters 48 to be directed radially outwardly through the surface of cylinder 10 whose outer surface is preferably polished.

FIG. l shows how lever 53 of the pressing device is rotatably mounted about stationary shaft 52 and resiliently urged in a counterclockwise direction away from cylinder 10 by spring 54. A follower screw 56 is mounted under the left end of lever 53 to which it is adjustably secured by nut 55. Follower 56 is maintained in engagement with cam 57 by spring 54; and cam 57 is mounted upon shaft 58 which is rotated by manually-operated wheel 59. As shown in FIG. 2, an initial pressing roller 60 and following

rollers

61 and 62 are mounted between a pair -of levers 53 mounted alongside both ends of cylinder 10. These pressure rollers are respectively covered by

silicone rubber coating

60a, 61a and 62a, and they are arranged to successively contact the circumference of printing cylinder 10 in the operating position shown in FIG. l.

As also shown in FIG. 2, initial pressing roller 60 includes a tube 63 whose ends are closed by end walls or flanges 65 rotatably mounted within ball bearings 64. A tubular conduit 66 extends through the hollow shafts extending from flanges 65. An annular heating element 66a is mounted concentrically upon conduit 66 which is supported within brackets 67 extending from levers 53.

By virtue of the heat provided to the surface 60a of initial pressure roller 60 and to printing cylinder 10, the paper fed between them is rapidly heated for facilitating its reception of the fluidized printing substance sublimated or melted from master sheet secured in va conventional manner Within notch 68 upon the surface of cylinder 10. The operating temperatures are arranged to cause the dyestuif to transfer from the master sheet only when it contacts the heated paper. This is facilitated by maintaining the surface 16a of cylinder 10 at a temperature ranging approximately from 220 C. and preferably between -190 C. and by maintaining the surface of heated pressure roller 60 at a temperature ranging approximately 120-180 C. The printing operation is improved by extending the time of contact of the paper with the heated master sheet which is accomplished by the contact of

unheated pressure rollers

61 and 62 in back of heated pressure roller 60.

FIG. 3 shows another form of this invention in which heated pressure roller 601 is mounted below cylinder 10 which in this case is covered by a silicone rubber coating 69.

Pressure roller or pulley 601 has a metal surface upon which is mounted one end of an endless belt 70, for example provided by a steel tape, and the other end of belt 70 is rotatably mounted upon an unheated return roller or pulley 71. Return roller or pulley '71 is mounted within inclined slots 72 in levers 531. Spring 73 reacting Ibetween a portion of levers 531 and the axle shaft of rollers 71 resiliently urges them away from pressure roller 60 and toward the surface of cylinder 11i. This maintains the upper loop of endless belt 70 in firm intimate engagement over a substantial distance upon the surface of cylinder 10. In this form of the invention it is also possible to utilize a cylinder 19 with a metal surface together with an endless belt 70 made of a fabric of synthetic or textile material. In a similar manner to that previously described, levers 531 are rotatably mounted upon shaft 52, and they are moved away from the surface of cylinder 10 in a manner similar to that previously described for replacing the master sheet secured upon its surface. Paper supply table 11 and

rollers

17 and 18 are accordingly aligned with the lower surface of cylinder 10 to cause the paper beingrprinted to pass below cylinder 10, which is in FIG. 3 rotated in a counterclockwise direction.

The form of this invention shown in FIG. 3 provides the advantage of maintaining the paper being printed continuously, rmly and uniformly engaged over its entire path of potential Contact with cylinder and master sheet 100 upon it. This improvement in effective contact area provided by the endless belt 70 of FIG. 3 over the

separate rollers

60, 61 and 62 of FIG. 1 provides increased printing eiciency and accordingly permits printing speeds to be increased at the same operating temperatures. If desired, the operating temperatures may also be decreased depending upon the operating speed. The greater the arc of contact of the pressing device with the cylinder, the greater is the printing eiliciency. However this extension in contact area is limited by the necessity to provide access for feeding and receiving the printing paper to and from the surface of the cylinder and by the space required for swinging levers 531 toward and away from the cylinder to provide access for changing master sheets.

What is claimed is:

1. An apparatus for printing copies on sheets of paper from a master sheet incorporating a printing substance which transforms to a fluid when heat is applied to it, said apparatus comprising a cylinder, rotatable support means mounting said cylinder for rotation about its axis, a source of heat disposed within said cylinder for heating its surface, a fastening means upon said surface of said cylinder for securing said master sheet upon it, a pressing device mounted in contact with the surface of said cylinder for pressing said sheets of paper in contact with said master sheet upon said cylinder, said pressing device having a movable surface for engaging in steady contact relative to said surface of said cylinder as it rotates past said pressing device, heating means disposed in heat transfer relationship with said movable surface of said pressing device for cooperating with said source of heat wit-hin said cylinder in transforming part of the printing substance in said master sheet to a fluid thereby imprinting it upon a sheet of paper contacted by said pressing device against said master sheet upon said cylinder, said pressing device including means for maintaining said paper in contact with said master sheet after said paper is contacted by the heated part of said pressing device, and said pressing device contact means including a movable endless belt which contacts said surface of said cylinder and said endless belt being movably mounted on said pressure roller and an unheated return roller.

2. An apparatus as set forth in claim 1 wherein said source of heat within said cylinder is constructed and arranged to heat said surface of said cylinder to a temperature ranging approximately from 160-220 C., and said heating means being constructed and arranged to heat said movable surface of said pressing device to a temperature ranging approximately from 120-180 C.

3. An apparatus as set forth in claim 2 wherein said temperature range of said cylinder is approximately from 170-190 C.

4. An apparatus as set forth in claim 2 wherein said heating means comprises a heater mounted Within said pressure roller, said cylinder and said pressure roller being rotatably mounted upon hollow shafts, supply lines connected to said source of heat within said cylinder and said heater within said pressure roller, and said supply line passing through said hollow shafts into the interior of said cylinder and said pressure roller.

S. An apparatus as set forth in claim 1 wherein said return roller is resiliently urged away from said heated pressure roller and toward said cylinder for stretching said belt between said rollers in firm contact with said surface of Said cylinder.

6. An apparatus as set forth in claim 1 wherein said surface of said cylinder is made of resilient material, and said endless belt is made of metal.

7. An apparatus as set forth in claim 6 wherein said surface of said cylinder is made of silicone rubber, and said endless belt comprises a steel tape.

8. An apparatus as set forth in claim 1 wherein said surface of said cylinder is made of metal, and said endless belt is made of fabric.

9. An apparatus as set forth in claim 1 wherein said source of heat comprises a number of strip heaters mounted longitudinally within said cylinder, and said strip heaters being spaced concentrically about the axis of rotation of said cylinder for heating said surface of said cylinder uniformly.

10. An apparatus as set forth in claim 9 wherein concave reectors are mounted longitudinally between said `strip heaters and said axis of rotation of said cylinder for directing said heat radially outwardly.

11. An apparatus as set forth in claim 10 wherein said concave reflectors are incorporated in a unitary tube having longitudinally arranged concave surfaces disposed between each of said strip heaters and the axis of rotation of said cylinder.

12. An apparatus as set forth in claim 1 wherein said source of heat comprises a number of strip heaters mounted longitudinally with said cylinder, a pair of end flanges being mounted within said cylinder for supporting said strip heaters between them and said end flanges being made of heat resistant material.

13. An apparatus as set forth in claim 12 wherein said heat resistant material comprises a ceramic material.

14. An apparatus as set forth in claim 1 wherein said pressing device is mounted upon a rotatable lever for making it movable toward and away from the surface of said cylinder, a spring means reacting against said lever, a cam means being mounted adjacent said lever, a follower upon said lever engaging said cam means, and a manually rotatable handle connected to said cam means for rotating it to move said lever and said pressing device away from and out of contact with said surface of said cylinder.

References Cited bythe Examiner UNITED STATES PATENTS 1,469,099 9/ 1923 Mayer 24-123 XR 1,479,819 1/ 1924 Kleuver 219-19.9 1,623,202 4/1927 Passman 24-123 XR 1,633,451 6/ 1927 McLaughlin et al.

219-19.18 XR 1,855,525 4/1932 MacArthur 101-407 XR 2,037,825 4/ 1936 Salsberg. 2,172,876 9/1939 Marchev lOl-132.5 2,197,036 4/1940 Ford lOl-132 2,222,984 11/ 1940 Marchev lOl-132 2,268,594 1/ 1942 Huber 101-426 2,329,152 9/ 1943 Breyer 10i-426 XR 2,401,670 6/ 1946 Spetz. 2,501,495 3/ 1950 Carroll et al. lOl-149.4 2,503,759 4/ 1950 Murray 101-426 XR 2,571,426 10/1951 Doniak 219-19.18 2,594,290 4/ 1952 Chavannes lOl-217 XR 3,046,771 7/ 1962 Bailey 34-123 3,141,404 7/ 1964 Newman lOl-149.5

ROBERT E. PULFREY, Primary Examiner.

EUGENE R. CAPOZIO, Examiner,

Claims

1. AN APPARATUS FOR PRINTING COPIES ON SHEETS OF PAPER FROM A MASTER SHEET INCORPORATING A PRINTIGN SUBSTANCE WHICH TRANSFORMS TO A FLUID WHEN HEAT IS APPLIED TO IT, SAID APPARATUS COMPRISING A CYLINDER, ROTATABLE SUPPORT MEANS MOUNTING SAID CYLINDER FOR ROTATION ABOUT ITS AXIS, A SOURCE OF HEAT DISPOSED WITHIN SAID CYLINDER FOR HEATING ITS SURFACE, A FASTENING MEANS UPON SAID SURFACE OF SAID CYLINDER FOR SECURING SAID MASTER SHEET UPON IT, A PRESSING DEVICE MOUNTED IN CONTACT WITH THE SURFACE OF SAID CYLINDER FOR PRESSING SAID SHEETS OF PAPER IN CONTACT WITH SAID MASTER SHEET UPON SAID CYLINDER, SAID PRESSING DEVICE HAVING A MOVABLE SURFACE FOR ENGAGING IN STEADY CONTACT RELATIVE TO SAID SURFACE OF SAID CYLINDER AS IT ROTATES PAST SAID PRESSING DEVICE, HEATING MEANS DISPOSED IN HEAT TRANSFER RELATIONSHIP WITH SAID MOVABLE SURFACE OF SAID PRESSING DEVICE FOR COOPERATING WITH SAID SOURCE OF HEAT WITHIN SAID CYLINDER IN TRANSFORMING PART OF THE PRINTING SUBSTANCE IN SAID MASTER SHEET TO A FLUID THEREBY IMPRINTING IT UPON A SHEET OF PAPER CONTACTED BY SAID PRESSING DEVICE AGAINST SAID MASTER SHEET UPON SAID CYLINDER, SAID PRESSING DEVICE INCLUDING MEANS FOR MAINTAINING SAID PAPER IN CONTACT WITH SAID MASTER SHEET AFTER SAID PAPER IS CONTACTED BY THE HEATED PART OF SAID PRESSING DEVICE, AND SAID PRESSING DEVICE CONTACT MEANS INCLUDING A MOVABLE ENDLESS BELT WHICH CONTACTS SAID SURFACE OF SAID CYLINDER AND SAID ENDLESS BELT BEING MOVABLY MOUNTED ON SAID PRESSURE ROLLER AND AN UNHEATED RETURN ROLLER.