US3552317A

US3552317A - Method of actuating a master and printing therefrom while on a printing drum

Info

Publication number: US3552317A
Application number: US619495A
Authority: US
Inventors: Gerhard Ritzerfeld
Original assignee: Individual
Current assignee: Individual
Priority date: 1966-02-08
Filing date: 1967-02-03
Publication date: 1971-01-05
Anticipated expiration: 1988-01-05
Also published as: GB1168113A; CH462849A; DE1259903B; FR1513691A; US3648609A

Abstract

The heat absorbing text of a printing master is placed in contact with a dye coating on a sheet and irradiated so that portions of the dye coating in contact with the heat absorbing text melt and adhere to the heat absorbing text while the remainder of the dye coating remains on the sheet when the same is pulled off the master.

Description

United States Patent Inventor Gerhard Ritzerfeld Franzensbader Strasse 21, Berlin- Grunewald, Germany Appll No. 619,495

Filed Feb. 3, 1967 Patented Jan. 5, 1971 Priority Feb. 8, 1966 Germany No. R42589 METHOD OF ACTUATING A MASTER AND PRINTING THEREFROM WHILE ON A PRINTING DRUM 10 Claims, 9 Drawing Figs.

U.S. Cl 101/471, 250/65.1 Int. Cl 841m 5/20, GOln 21/34 Field of Search 101/468,

References Cited UNITED STATES PATENTS Russell Miller Raczynski et a1. Raczynski et a1. Roshkind Beatty et a1.. Ritzerfeld Russell et al Limburger Primary Examiner-William B. Penn Attorney-Michael S. Striker ABSTRACT: The heat absorbing text of a printing master is placed in contact with a dye coating on a sheet and irradiated so that portions of the dye coating in contact with the heat absorbing text melt and adhere to the heat absorbing text while the remainder of the dye coating remains on the sheet when the same is pulled off the master.

' SHEET 2 BF 9 In v e nlar PATENTED m 5197| SHEET 3 BF 9 In venfor Ki,

PATENTEU JAN 5197i sumuor g lnven [or PATENTEDJAH 5197! 35521317 sum 5 OF 9 Fly. 5

PATENTEU JAN 5197! SHEET 8 OF 9 lnvenior:

METHOD OF ACTUATING A MASTER AND PRINTING THEREFROM WHILE ON A PRINTING DRUM BACKGROUND OF THE INVENTION imprints. The number of copies which can be obtained depends on the type of hectographic master and is maximal 400 copies. Thereupon, a new master has to be written.

It has been proposed to regenerate the master by means of a hectographic inking sheet which is subjected to differentiated heat radiation. This requires a special thermographic apparatus for producing a differentiated infrared radiation. The

use of an additional apparatus is uneconomical and time consuming so that a certain given amount of orders or invoices cannot be handled in the required time.

Independently of the above disadvantages, organizational duplicating systems require the use of an existent master in different successive printing operations, each of which requires a newly written additional master, for example for part deliveries. If the main master is used for a great number of copies, and the additional masters only for smaller numbers of copies, a substantial color difference between the parts of the copies made by the main master and theparts of the copies made by the additional masters occurs which results in a poor appearance of the copies if purple duplicating ink is'used, and which is intolerable if black hectographic inking sheets are used. However, particularly the use of black inking sheets which can produce only a limited number of copies, is particu- Iarly necessary for producing a deep black imprint of all parts of the text on all copies. The use of hectographic masters with duplicating ink brings about soiling of the fingers of the typist making the master and of the machine operator during the duplication and and during the regeneration of the master. Also, the use of hectographic masters in high speed printers in modern data processing machines causes difficulties due to the soiling of the high speed printer and of the person operating the same. It has been recently suggested to use for writing or printing of masters soot containing inks which do not contain a hectographic dye.

' SUMMARY OF'TI-IE INVENTION It is one object of the invention to overcome the disadvantages of the prior art regarding making and activating duplicating masters, and to provide an arrangement which permits the making, regenerating and activating of hectographic duplicating masters of high quality without soiling the machine or its operator.

Another object of the invention is to provide a method for making or regenerating a hectographic'duplicating master in a short time, and by using the duplicating machine. I

With these objects in view, the present invention is concemed with the activation of a master whose text is radiation to the text. When the sheet is removed with the remaining coating, the radiation absorbing text'of the master is covered with a dye coating adapted to be transferred to copy sheets moistened with alcohol. 1

The dye used in the coating is preferably a triphenylmethane dye embedded in a bonding'substance, and the radiation is preferably either infrared radiation, or high frequency waves producing sufficient energy to melt the dye coating only where the radiation is absorbed by the text of the master which is in contact with the dye coating.

When the melted dye has hardened again and is securely attached to the text of the master, the coated sheet is either manually or mechanically pulled off the master.

It is possible to transfer a coating and to separate thesheet from a master during 1 revolution, or during 2 successive revolutions of a duplicating drum or other carrier.

In one embodiment of the invention, the coated sheet is a band-shaped web which is taken off a first reel and wound up on a second reel. The section between the reels is pressed against the master and irradiated. The wind-up reel is driven from the rotary carrier of the master through a friction roller so that the web is moved substantially in synchronism with the revolving master.

In another embodiment of the invention, the coated sheet is superimposed on the master, and both sheets are held tight on the periphery of the carrier or duplicating drum.

The novel features which are considered as characteristic for the invention are set forth'in particular in the appended claims. The invention itself, however, both as to its constructionand its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary sectional view illustrating a duplicating machine provided with the apparatus of the invention in a position of rest;

FIG. 2 is a fragmentary sectional view of the apparatus illustrating another operational position at the start of the transfer of dye to the master;

FIG. 3 is a fragmentary sectional view illustrating the apparatus in another operational position shortly before removal of the coated sheet from the master;

FIG. 4 is a fragmentary sectional view illustrating an operational position of the master in which the coated sheet is pulled off the master;

FIG. 5 is a fragmentary sectional view illustrating a modified construction of the pressure means in a position of rest of the duplicating machine, parts illustrated in FIGS. 1 to 4 being omitted in FIG. 5 for the sake of simplicity;

FIG. 6 is a fragmentary sectional view taken on lines D-E in FIG. 3; 7

FIG. 7 is a fragmentary sectional view illustrating another embodiment of the invention with a detachable unit which can be used in an existent duplicating machine;

FIG. 8 is a fragmentary sectional view illustrating a duplicating machine provided with the unit shown in FIG. 7, wherein the pressure means are modified; and

FIG. 9 is a fragmentary sectional view taken on lines I-H in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, a duplicating drum 1 is mounted on a rotary shaft 2 and has a i first holding means for clamping a master 4 to the periphery of drum 1. The master has on its outside a carbon mirror script text 6, and on its inside a positive legible outline 5 of the text. A sheet 9 has an inner coating 10 consisting of a dye such as a triphenylmethane dye in a bonding base, and is held in a second holding means 7. In the operational position of FIG. 1, the apparatus is in a position of rest, but when rotation of the duplicating drum 1 is started, the coated

sheet

9, 10 is superimposed on the outside of master 4. A manually operable rod 11 has a cutout 14 which can be hooked onto a corresponding arresting part of a bracket 15 by which rod 11 is guided. When rod 11 is moved to the right, lever 16 turns about pivot 17 in the direction of the arrow A, and shifts, while lever 18 turns about pivot 19, link 20 in the direction of the arrow B. Toggle levers 21 and 22 are displaced along the path defined by lever arm 23 turning about pivot 19 so that the support 24 with

pressure rollers

12 and 13 and the source of radiation 25, move away from duplicating drum 1 and assume an inoperative position,

wheel 129 from theduplicating drum.

Parts 126 to 135 constitute a l-revolution clutch effecting stopping of duplicating drum 1 after a-singlerevolution.

A motor, not shown, drives through a gear. 126, the gear- 127 which is freely rotatableon shaft 2 and fixedly connected with a ratchet wheel l29an'd a'flange 142. When latch 132 is held 1 by spring 134 in the position of FIG. 1', a pawlv130 is arrested and cannot turn about its pivot 135 under theactionof spring 131 toa position engaging the ratchet wheel and coupling the same through pivot l35gto the duplicating drum 1 so that the same is arrested in the position of FIG. 1.

-When the operator releases latch-1'32 by turning the same about pivot 133,-spring 131 movespawl 130 toitsrcoupling position engaging ratchet wheel 129, and theduplicating drum starts its rotation in clockwise direction of the arrow until pawl l30vengages latch 132 after I revolution ofthe drum, and is separated from the ratchetwheel sothat the drum stops. The

duplicating drum is part of a' conventional duplicating machine which includes a counter pressure roller'la, a pair. of

sheets are supplied.

In the operational'position of FIG. 2, the duplicatingdrum has turned so-far-that the pressure roller 13 engages'theout- 1 side of 'the coated sheet 9 and presses the same with the ink coating .10 againstrthe carbon text .6 of the master-which has radiation absorbing properties. Counter pressure roller in also holds the coatedsheet '10 superimposed on 'themaster. The source of radiation 25, which mayproduce infrared radiation .or a highfrequency radiation, irradiates the leading-portions of the coated sheet 9 and of the master 4 in theposition-of 'FIG. 2, sincetsupport 24 is held in its operative position by the lever system due to the'fact that rod 11 is in its operative position. I

During further rotation of the duplicating drum, the ap- ,paratus .assumes the position of FIG. 3' so that consecutive pairs of sections of the coated sheet and of the master 4 are irradiated.ln the position of FIG. 4, the superimposed sheets "havepassed beyond'the pressure roller means 12, 13, and the duplicating drum approaches its-position of rest in which pawl 13.0twill engage latch 132 and separate the driven ratchet 'Referring again to FIG. 2, it is not necessary toenergize the source of radiation when the duplicating drum is in the positions of FIG. 1 or'FlG. 4, in which the coated sheet and master are not located in the region of the source ofradiation 25.

As shown in FIG. 2, a part circular member 76a is secured to the end face of drum 1 and .is engagedby slide contactl76 which is connected witha switch 75 in the circuit,.not shown, of the radiation source 25. Radiation source .-25'is only ener gized when slide contact 76 is engaged by the part circular .inember 76a. which is disposed to close the circuit of the radiation source shortly before the same is passed by the leading edges of

sheets

9 and 4, and to open the same shortly after the trailing edges of the sheet have passed the radiation source,

The circuit of the radiation source is closed such a time before the leading ,parts of the superimposed

sheets

9 and 4 reach the region 'of radiation source 25, that the same has warmed -up and is fully heated when acting on the superimposed sheets.

The

pressure rollers

12 and 13

smooth sheets

4 and 9 and hold the same in contact with each other and with the periphery of the duplicating drum. The carbon text 6 on master 4 is irradiated through the dye coating 10 of sheet.9 and is heated so that the portions of the dye coating abutting the heat absorbing carbon text are heated to such a tempera- Y ture as to melt and adhere to the heat absorbing carbon text of the master sheet, while the remainder of the dye coating, which did not receive a heat reflex from the carbon text remains attached to sheet 9.

'FIGSJ3 and 6 showth'e apparatusin axpositionin-which the source ofi radiation-is :passedbysections of the superimposed sheets. to-successively irradiate the entire- 'coatedl sheet "and master sheet. The-leading.edgesofccoated sheet 9 and master :sheet4 and the holding'rneans7 -and.3..approaeh a%giippen'33. Holding means 7- of the rcoatedsheetllt) :is opened, and: the released leadingpart ofcoated -sh eeti:10 is being'pushed-byQan :ejector 1 member away from: the .:peripheral surface amine duplicatingdrum and intofthe region ofgripperf33. 1

"As best seen in "FIG. 6, two ;-releasing members #94 are mounted .on. a shaft =93 andcooperate-withFholding' means '7. During rotation of the duplicatingidrum, cam 95 which is mounted on a pivot '30 actsz'onta' roller 97of -cam=92 onshaft -93 to effect opening of holding means 7 at theproper moment. A' manually. operatedrod" 9.1, guided-in :a' bracket 96,. is connected-with.carn 95and'is'shiftable to'a position in which its cutout 91a .is hooked into bracket 96" so that cam 95 is retracted to an inoperative. position in which itcannotactuate camfollower means -92, 97:to;open=holding means7. hile holding; means *7 is "thus closed an'd inoperative, I duplicating operations may becarried out.lf cam 95 would'remainopera- :tiveduring duplicating operations, holding means 7, which is not used during such operation, would "be unnecessarily opened andclosed. When holding means -7 has. been opened in the position of FIG. 3,:the.;roller 27-of a camfollower 28 one shaft .29 isengaged by-.a carnr32awhich-ismountedon-a pivot 3l,'and turns cam follower lever 28 inithe'direction of the arrowiCi-sothat shaft.-29-tums in its bearing'simthe end walls of theduplicating -.drum 7.2 andrdisplaces ejector 126 which pushes .the leading part: of the .co'atedsheetQ-away. from the .duplicating'drum and into the region o'fsgripp'er v33. Cam-32 is connected with a manually; operable.rod 99, and can be turned by-the sameto an inoperative .zposition spaced from roller 27 so that ejector 26 is notactuated duringa-duplicating operation. g After ejector 26 has-,perfomied its function, cam follower roller 97-is movedbyzthe duplicating drum beyond cam 95, so

that aspiring-connected withcamfollower 92-retnmsmember 94 to its original position-.closingholding means 7. g

The :rotary movement of duplicating=drum -l carries the released leading .portionof a coated sheet 9 into'gripperl33 'which has a fixed jaw and-a movable jaw which is turnable an;

' :shaft.35 which'rigidly supports'thefixedjaw. The movable :jaw

ispart of .an angular lever34loadedby a spring 36and carrying a .camsfollowerroller38 .cooperatingwitha ro'tarycam 37 secured to a shaft 42 .driven'througha gear train 41, 40, .39 from'the duplicating'drum. Cam.37"hassuch-a shape 'that the gripper is open until the leadingedge of thecoated sheet 9is moved by the duplicating drum between the two jaws of gripper 33.-Thereupon,'a "higher portion of 'cam 37 engages cam follower'roller38 andc'loses'the gripper so that the leading edge of the coated sheet 9is clamped,iasshown in FIG. -4.

During :further turning movement of duplicating drum '1, roller.27moves beyond .cam32 and permits the-return'of-lever arm 28 by aspring'to its original'position in which ejectors.26 are retractedinto the interior-of theduplicating drum whose peripheral wallhas cutoutsfor the'passage'of ejectors 26.

Referring nowto FIG. 4, gripper 33 gradually. pulls the coated-sheet'9off master 4 which'continues to move with the duplicating drum l. Since the coat 10 adheres to the master,

the coated sheet 9 forms a loop. The portion of coating 10 ad- When the coated sheet 9 is completely separated from.

master 4, roller 38 is moved by the action of spring 36 tothe lower portion of cam 37, and the gripper opens and relases the coated sheet 9, which is either manually removed from the machine or guided into a receptacle, not shown.

Cam 37 is mounted on shaft 42shiftable in axral direction to" an inoperative position spaced from cam follower roller-38 of gripper 33 so that duplicating operations can'be carried out without operation of gripper33. 1 v- FIG. 5 corresponds to FIGS. 1 and 6 as far as the duplicating machine, the gripper, the ejector, and the second holding means 3 and 7 are concerned, but the radiation and pressure unit is modified. The source of radiation 25 is mounted on a support 45 which is operated from a manually operable rod 14. The source of radiation is located within a glass cylinder 44 covered with a soft transparent layer 43. The

tubular member

44, 43 abuts the peripheral surface of the duplicating drum 1, and the

superimposed sheets

9 and 4 along a first line. Two spaced lines of the

tubular member

43, 44 are engaged by a pair of

rollers

46, 47 mounted on support 45. Consequently, the tubular transparent member 43', 44 is rotatably supported at three points, and rotates due to the frictional engagement with the peripheral surface of the duplicating drum 1 or with sheet 9. The pressure of the

tubular member

43, 44 on the superimposed sheets smoothes the same and holds the dye coating in contact with the heat absorbing carbon text on the outside of master 4. The pressure rollers used in the embodiment of FIG. 1 are replaced by the transparent

tubular pressure tube

44, 43.

The removal of the coated sheet 9 from the master has been described with reference to FIG. 4 to be carried out at the end of the same revolution during which the coated sheet is irradiated, and portions of its coating transferred to the heat absorbing text of master 4. However, it is possible irradiate and master during a first revolution, and to open holding means 7, operate ejector 26, and close gripper 33 during a second revolution of the duplicating drum.

FIGS. 7, 8 and 9 illustrate a modified embodiment of the invention in which the irradiating and pressure unit can be attached to and detached from a standardduplicating machine. The duplicating drum 1 has only one holding means for the master sheet 4, and the coated sheet is not mounted on the duplicating drum, but is a band-shaped web 79 whose dye coating 82 is located opposite the peripheral surface of the duplicating drum and the carbon text 6 on the outside of master 4. A

support member

88, 136 can be operated to move between the inoperative position shown in FIG; 7 to an operative position in which a drive roller 86 frictionally engages the peripheral surface of duplicating drum 1 and is rotated by the same. A pulley 83 is connected by slide clutch 100 to the drive roller 86 and drives through a belt 84 a pulley 81 on a shaft 76 rotating the takeup reel of the band-shaped coated web 79. The coated web 79 is unwound from a takeoff reel on shaft 80 which is braked by a bar brake 112, biased by spring 113 and mounted on a pivot 111. During duplicating operations, when the coated web must not engage the duplicating drum, the support 88, with cam 136 is in the retracted position shown in FIG. 7, and the drive roller 86 is separated from the duplicating drum so that the same can perform the usual duplicating operations producing imprints of the master on copy sheets.

In order to hold the device in this inoperative position, the

support

88, 136 is shifted by a linkage connected with the manually operated rod 102.

When the rod 102 is shifted to the right and cutout 10l is hooked onto bracket 103, lever 115 turns in the direction of the arrow F about pivot 116 and shifts, while turning lever 117 about pivot 118, latch 119 in the direction of the arrow G. Due to this motion, toggle levers 120, 121, which are controlled by guide lever 122 turning about pivot 118, move the source of radiation 25, the

pressure rollers

12, 13, the drive roller 86, and the support 87 of the radiation source by means of

support

88 and 136 to the inoperative position spaced from the duplicating drum.

Support

88, 136 is mounted on support 87 of the source of radiation, which also supports pressure rollers l2 and 13 for rotation.

The housing 90 on which the above-described parts are mounted has brackets 137, 138, 139 and 140 which are mounted in slots in the sidewalls of the duplicating machine. When the dyeing of the master 4 is required, cam 109 causes movement of

support

88, 136 to the operative position in the proximity of the duplicating drum 1 when the leading part of the master approaches the region of the source of radiation 25. Spring 124 holds the cam follower roller in this position of rod 102 on the lower portion of cam 109. A switch 75 has a slide contact 76a which cooperates with an arcuate contact 76a on the end walls of the duplicating drum as described with reference to FIG. 2 so that the source of radiation 25 is energized shortly before the leading part of the master approaches the source of radiation, and is deenergized when the trailing portion of the master has passed beyond the same.

As mentioned above, the source of radiation may produce infrared radiation, or a high frequency ion radiator may be used. The transfer of dye from the coated sheet 79 to the text 6 on master 4 may be effected during 1 or several revolutions of the duplicating drum. The brake 112 prevents inertia rotation of the takeoff reel which may move the web into contact with the drum when the unit is moved to the inoperative position of FIG. 7 in which the takeup reel is not driven by drive wheel 86 since the same is spaced from the drum.

If the counter pressure roller la, transporting rollers 1b and the moistening means 10 are omitted, the apparatus is limited to the dyeing of master sheets, and is not used for duplicating operations so that drum 1 constitutes a carrier for the master 1 and is not used as a duplicating drum.

FIG. 8 illustrates a modified arrangement which corresponds to the construction described with reference to FIG. 7, but has instead of

pressure rollers

12 and 13, a tubular transparent pressure member consisting of a glass tube 44 with a thin transparent cover 43, and enveloping the source of radiation, as described with reference to FIG. 5.

The method of the invention permits the use of a conventional duplicating machine for providing the text of the master with a layer of dye, or activating a master, the dye of whose text is exhausted by imprints on many copy sheets since the remaining text permits the adhering of dye from the coated sheet, as explained above.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of printing machines differing from the types described above.

While the invention has been illustrated and described as embodied in a duplicating machine provided with a unit for transferring a dye from a coated sheet to the carbon text of a master, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

I claim:

1. A method of activating a master and printing with the same, comprising attaching to a printing drum a master having on one side radiation absorbing means forming a reverse text so that said one side faces outward in a position ready for printing; placing at least a section of a sheet having on one side a coating of a transferable dye with said one side in contact with said one side of said master; rotating said printing drum with said master; moving said sheet in unison with said master so that pairs of sections of said sheet and master are successively superimposed; irradiating said superimposed sections and said coating between the same whereby radiation absorbed by said radiation absorbing means heats the portions of said coating which are in contact with said radiation absorbing means so that said heated portions of said coating adhere to said radiation absorbing means of said master; removing said sheet from said master while the same remains attached to said rotating printing drum so that said adhering heated portions remain on said radiation absorbing means whereby the reverse text formed by said heat absorbing means of said master is activated while the coating remaining on said sheet is removed with the same; placing a plurality of copy sheets successively in contact with said master during successive revolutions, respectively, of said printing drum with said master so I rotation of said printing drum; and deenergizing said source in a second selected angular position of said printing drum when 'the trailing superimposed sections of said sheet and master have passed said source during further rotation of said printing drum.

3. The method of claim 1 wherein said sheet is superimposed on said master so that all said heat absorbing means are in contact with said coating.

4. The method of claim 1 wherein said sheet is irradiated from the other side of said sheet with infrared radiation to melt said portions of said coating; and wherein said dye of said coating is a triphenylmethane dye embedded in a bonding substance.

5. The method of claim 1 wherein successive pairs of sections of said sheet and master are irradiated from the outer other side of said sheet during rotation of said printing drum.

6. The method of claim 1 wherein said sheet is a bandshaped web; and comprising successively unwinding sections of said web from takeoff means; placing each unwound section on said master; and winding up each unwound section after irradiation so that each wound-up section is removed with the remaining coating from said master.

7. The method of claim 1 wherein said sheet is manually removed from said master after irradiation.

8. A method of activating a master and printing with the same, comprising attaching to a printing drum a master having on one side radiation absorbing means forming a reverse text so that said one side faces outward in a position ready for printing; placing at least a section of a sheet having on one side a coating of a transferable dye with said one side-in contact with said one side of said master; rotating said printing drum with said master; moving said sheet in unison with'said master so that pairs of sections of said sheet and master are successively superimposed; irradiating said superimposed sections and said coating between the same whereby radiation absorbed by said radiation absorbing means heatsthe portions of said coating which are in contact with said radiation absorbing means so that said heated portions of said coating adhere to said radiation absorbing means of said master; gripping and holding the leading edge of said sheet during rotation of said printing drum with said master so that said sheet is peeled off said master while the same remains attached to said rotating printing drum so that said adhering heated portions remain on said radiation absorbing means. whereby the reverse text formed by said heat absorbing means of said master is ac,- tivated while the coating remaining on said sheet is removed with the same; placing a-plurality of copysheetssuccessively in contact with said master during successive revolutions, respectively, of said printing drum with said master so that legible imprints of said reverse consisting of said coating are made on a plurality of copy sheets before said master is again activated.

9. The method of claim 8 wherein said sheet and said master are irradiated during a first revolution of said printing drum; and including gripping and holdingof the leading edge. of said sheet during a second revolution of said printing drum so that said sheet with said remaining coating is removed from said master.

10. The method of claim 8 wherein said sheet and said said master.

Claims

1. A method of activating a master and printing with the same, comprising attaching to a printing drum a master having on one side radiation absorbing means forming a reverse text so that said one side faces outward in a position ready for printing; placing at least a section of a sheet having on one side a coating of a transferable dye with said one side in contact with said one side of said master; rotating said printing drum with said master; moving said sheet in unison with said master so that pairs of sections of said sheet and master are successively superimposed; irradiating said superimposed sections and said coating between the same whereby radiation absorbed by said radiation absorbing means heats the portions of said coating which are in contact with said radiation absorbing means so that said heated portions of said coating adhere to said radiation absorbing means of said master; removing said sheet from said master while the same remains attached to said rotating printing drum so that said adhering heated portions remain on said radiation absorbing means whereby the reverse text formed by said heat absorbing means of said master is activated while the coating remaining on said sheet is removed with the same; placing a plurality of copy sheets successively in contact with said master during successive revolutions, respectively, of said printing drum with said master so that legible imprints of said reverse text consisting of said coating are made on a plurality of copy sheets before said master is again activated.

2. The method of claim 1 wherein said superimposed sections are irradiated by a source of radiation; comprising energizing said source of radiation in a first selected angular position of said printing drum when the leading superimposed sections of said sheet and master approach said source during rotation of said printing drum; and deenergizing said source in a second selected angular position of said printing drum when the trailing superimposed sections of said sheet and master have passed said source during further rotation of said printing drum.

6. The method of claim 1 wherein said sheet is a band-shaped web; and comprising successively unwinding sections of said web from takeoff means; placing each unwound section on said master; and winding up each unwound section after irradiation so that each wound-up section is removed with the remaining coating from said master.

8. A method of activating a master and printing with the same, comprising attaching to a printing drum a master having on one side radiation absorbing means forming a reverse text so that said one side faces outward in a position ready for printing; placing at least a section of a sheet having on one side a coating of a transferable dye with said one side in contact with said one side of said master; rotating said printing drum with said master; moving said sheet in unison with said master so that pairs of sections of said sheet and master are successively superimposed; irradiating said superimposed sections and said coating between the same whereby radiation absorbed by said radiation absorbing means heats the portions of said coating which are in contact with said radiation absorbing means so that said heated portions of said coating adhere to said radiation absorbing means of said master; gripping and holding the leading edge of said sheet during rotation of said printing drum with said master so that said sheet is peeled off said master while the same remains attached to said rotating printing drum so that said adhering heated portions remain on said radiation absorbing means whereby the reverse text formed by said heat absorbing means of said master is activated while the coating remaining on said sheet is removed with the same; placing a plurality of copy sheets successively in contact with said master during successive revolutions, respectively, of said printing drum with said master so that legible imprints of said reverse consisting of said coating are made on a plurality of copy sheets before said master is again activated.

9. The method of claim 8 wherein said sheet and said master are irradiated during a first revolution of said printing drum; and including gripping and holding of the leading edge of said sheet during a second revolution of said printing drum so that said sheet with said remaining coating is removed from said master.

10. The method of claim 8 wherein said sheet and said master are irradiated during a revolution of said printing drum; and including gripping and holding of the leading edge of said sheet during said revolution of said printing drum so that said sheet with said remaining coating is removed from said master.