US3150262A

US3150262A - Thermographic copying machine

Info

Publication number: US3150262A
Application number: US20039A
Authority: US
Inventors: John W Ulseth; Robert A Halberg; John A Gravelle
Original assignee: Minnesota Mining and Manufacturing Co
Current assignee: 3M Co
Priority date: 1960-04-05
Filing date: 1960-04-05
Publication date: 1964-09-22
Anticipated expiration: 1981-09-22
Also published as: GB980625A; DK104277C; DE1422505A1; CH432431A; CH413879A; BE598468A; SE304484B; NL6700650A; GB980626A

Description

Sept. 22, 1964 J. w. ULSETH ETAL 3,150,262

.THERMOGRAPHIC COPYING MACHINE Filed April 5, 1960 3 Sheets-Sheet 1 INVENTORS'. ROBERT A. HALBERG JOHN W. ULSETH BY JOHN A. GRAY/ELLE ATTORNEYS Sept. 22, 1964 J, w. ULSETH ETAL THERMOGRAPHIC COPYING MACHINE 5 Sheets-Sheet 2 Filed April 5, 1960 INVENTORS. ROBERT A. HALBERG JOHN W- ULSETH JOHN A. GRAVELLE P 22, 1964 J. w. ULSETH E'IAL 3,150,262

THERMOGRAPHIC COPYING MACHINE Filed April 5, 1960 3 Sheets-Sheet 5 m \n a INVENTORS.

7 ROBERT A. HALBERG N w. ULSETH N A. GRAVELLE w/zmww ATT ORNEYS U d s P We Patented Sept. 22, 1964 FIGURE 1. Disposed between the pressure roll 18 and 3,150,262 the rolls 21 and 22 is a thin walled radiant energy trans THERMOGRAPHIC COPYING MACHINE John W. Ulseth, St. Paul, Robert A. Halberg, West St- Paul, and John A. Gravelle, Roseville, Minn, assignors to Minnesota Mining and Manufacturing Company, St. Paul, Minn, a corporation of Delaware Filed Apr. 5, 1960, Scr. No. 20,039 12 Claims. (Cl. 250-65) This invention relates to improvements in thermographic copying machines and has particular reference to a low cost machine capable of rapidly and efficiently producing any desired number of reproductions of graphic originals on heat sensitive copy paper. The improved machine is light in weight and readily portable, having physical dimensions approximating those. of a portable typewriter. The low contour of the improved machine makes it particularly suited to desk-top use.

compactness is lent to the improved machine by the embodiment therein of a transparent tubular copy roll within which a lamp and reflector assembly is mounted, there being means forpressing a composite of graphic original and copy sheet into intimate contact with the outer surface of the copy roll as the composite passes the area in which the irradiation of the lamp is concentrated by the reflector assembly. The improved machine has variable speed means and is provided with a single control knob which affords selective control of energization of both the lamp and the drive motor as well as selective control of the position of the lamp and reflector assembly and the speed at which the copy roll is driven. The efficiency of the machine is enhanced by the use of a novel reflector construction affording improved reflectance and stability characteristics, as well as by the use of a novel copy roll construction tending to insure Wrinkle free composite orientation during travel through the machine and particularly during irradiation.

The invention can best be understood by reference to the accompanying drawings illustrating one complete embodiment of the presently preferred form of the invention in which:

FIGURE 1 is a plan view showing the improved thermocopying machine with the cover removed, parts being broken away and shown in section;

FIGURE 2 is a vertical sectional view of the improved machine taken generally along the line II-II of FIG- URE l;

FIGURE 3 is a perspective view showing the coordination of certain of the parts of the improved machine which are under the control of the single control knob;

FIGURE 4 is an enlarged vertical sectional View taken through the lamp and reflector assembly of the improved machine; and

FIGURE 5 is a greatly enlarged fragmentary plan view of the copy roll to show the variation in the diameter of said roll.

Referring more particularly to FIGURES 1 and 2, the form of the improved copying machine selected for illustration therein comprises a rectangular base member and a complemental rectangular removable cover 11 (FIGURE 2). Mounted on the base 10 is a frame 12 having opposite end walls 13 and 14, a rear wall 15 and apertured front and top walls 16 and 17 respectively.

Mounted in suitable bearings carried by the frame end walls 13 and 14 is a pressure roller 18 comprising a metal rod or shaft 19 having bonded thereto a thick cylindrical sleeve'Zt) of very soft resilient material, for example very soft rubber. Also mounted in suitable bearings carried by the frame end walls 13 and 14 are a pair of spaced rubber covered rolls 21 and 22, the roll 21 having an integral drive shaft 23 which extends beyond the frame end wall ,14.and carries adrive pulley 24 as shown in missive copy roll 25 for example of heat resistant glass. It will be observed in FIGURE 2 that the spacial relationship between the rolls 1%, 21 and 22 is such that the copy roll 25 deforms the pressure roll 18 to form a nip area of substantial width extending the full length of the roll 18. In the presently preferred form of the invention, the pressure roll 18 is 2 inches in diameter, the copy roll 25 is 1.780 inches in diameter and 0.055 inches in wall thickness. The nip area is inch in width and the pressure contact between the rolls 1S and 25 across the nip varies from 0 to- 9 pounds per square inch, the pressure curve being sinusoidal with the pressure peak at the midpoint of the nip.

The rolls 18, 21 and 22 constitute the bearings for the copy roll 25, the latter being prevented from substantial axial movement by suitable thrust bearing members (not shown) engageable therewith and carried by frame end walls 13 and 14. The copy roll 25 is driven in a clockwise direction as viewed in FIGURE 2 by the roller 21 which, in turn, is driven by an endless belt 26 which connects the pulley 24 to the output drive pulley 27 of variable speed drive means comprising a variable speed transmission 28 and a drive motor 29. The variable speed transmission 28 has a frame 28a comprising spaced parallel wall members 3th, 31 and 32. held in assembled relation by

rods

33 and 34 fixed thereto. The motor drive shaft 41 extends through the frame wall 30 and carries a gear type pulley 35. A generally u shaped carrier member 36 is formed with a pair of spaced parallel side plate members 37 and 38 and with a transverse connecting plate member 39 having an intermediate plate member 40 stamped therefrom and extending parallel with side plates 37 and 38. The carrier member 36 is bearinged on the Wall members 3% and 31 for pivotal movement about the axis of the motor drive shaft 41. The intermediate plate member 49 is provided with suitable bearing means for supporting a short shaft 42 which carries a gear type pulley 43 on one side of the plate 40 and a shallow slope driving cone 44 on the other side. An internally toothed endless belt 45 connects the motor drive pulley 35 to the pulley 43 to afford a positive driving connection between the motor 29 and the cone 44. Fixed to the side plate 38 of the carrier 36 is a gear quadrant 46 which is in toothed engagement with a longitudinally slidable rack 47 for a purpose to be later described.

A shaft 48 is axially slidably mounted in suitable bearings in the frame members 31 and 32 and has fixed to one end thereof an enlarged disc 49 carryinga peripheral facing ring 50 of frictional material. The facing ringSt) of the disc 49 is biased into frictional engagement with the cone 44 by a leaf spring 51 fixed atone end tothe frame member 32 and having its free end engaging the end of the shaft 48 opposite the disc 49. The output pulley 27 is carried by a shaft 52 mounted in suitable bearings carried by frame members 31' and 32, said shaft also carrying a gear 53 which meshes with an elongated gear 54 fixed on the shaft 48, all as shown in FIGURE 1.

It will be observed in FIGURE 2 that the axis of the motor shaft 41 is spaced below and parallel with the axis of the shaft 48. When the parts are in the position the dot and dash line position thereof shown in FIGURE 2, the annular frictional facing 50 contacts the cone 3 V 44 near the apex thereof so that the copy roll 25 is driven at minimum speed for a given speed of rotation of the motor drive shaft 411. Between these two limits,

the speed of the copy roll 25 can be varied infinitely in accordance with the position of the rack 47 intermediate the solid line and dot and dash line extreme positions thereof shown in FIGURE 2. V

The base member 16 is provided with slidable mounting means for an elongated channel shaped actuating or slide member 55 having fixed thereto a manually engageable control knob 56. A Bowden wire '7 has one end fixed to the rack 47 and extends through a sheath 58 fixed to a bracket 58a (FIGURES 1 and 2) on base member 10, said Bowden wire having its opposite end fixed to the slide member 55 as at the screw 59. It will be observed that the position of the slide 55 and control knob 56 shown in solid lines in FIGURE 1 and shown in dot and dash lines in FIGURE 3 afiords maximum speed of the copy roll because'this position corresponds to the solid line positionsof the parts in FIGURE 2. ,Movement of the knob 56 and thereby of the slide 55 to the left of the position shown in solid lines in FIGURE 3 moves the rack 47 forwardly to the position shown in dot and dash lines in FIGURE 2 and pivots thequadrant 46 to the position shown in FIGURE 3, correspondingly pivoting the carrier 36 as aforedescribed.

A normally closed electrical switch 69 is suitably mounted on the base 10 and has a depressable button 61 positioned to be depressed by a cam member 62 formed on the adjacent end of the slide member 55 and forming an extension of the rear flange thereof. The switch 66 is connected in circuit with the motor 2% and with a source of alternating current by means (not shown) which may include a step-up transformer 63. When the slide is moved to the left to the extreme position shown in solid lines in FIGURE 3, the button 61 of switch 66 is depressed to open the circuit to the motor 29 and prevent energization thereof. It is apparent, therefore, that movement of the knob 56 to the right from the dot and dash line off position of FIGURE 1 effects closure of the contacts of the switch 60 and operation of the motor 29 with concomitant rotation of the copy roll 25 at a speed depending upon the distance the knob 56 has been moved toward its solid line position shown in FIGURE 1.

The base member It) and frame 12 are provided with means at the front of the machine defining an inlet throat 64 through which a composite of a graphic original and copy sheet (not shown) can be introduced and by which such composite is guided toward the underside of the nip of the pressure roll 18 and copy roll 25. Above the aforementioned nip, the cover 11 is provided with an outlet throat 65 through which a composite is guided from the nip of rolls 18 and 25.

Means is provided for subjecting a composite of graphic original and copy sheetto brief intense irradiation while passing through the nip of the rolls 18 and 25. The preferred irradiating means takes the form of a lamp and reflector assembly 66 comprising an elongated tubular lamp 68 disposed substantially axially ofra reflector 67, said assembly 66 extending within the copy roll 25 as shown in FIGURES l and 2. .The reflector 67 and lamp 68 of the assembly 66 are fixed relative to each other and,as shown most clearly in FIGURES l and 3, said assembly is supported at its opposite ends by pivotal arms 69 and 70 which are pivoted, respectively on pins 71 and 72 supported in suitablebearings carried by:

the side walls 13, and 14 of frame 12 respectively. The assembly 67 is biased toward its operative position shown j in the solid lines in FIGURE 2 and in dot and, dash lines The mountinga'means for actuatingthe reflector and,

lamp "assembly, 66 permits movement thereof from its operative position closely adjacent the inner surface of the copy roll 25 at the nip area of said roll and roll 18 to a retracted inoperative position substantially centrally of the roll 25 and shown in solid lines in FIGURE 3. Means is provided for actuating the lamp and reflector assembly 66 to its inoperative position against the bias of the

spring

73 and 74 whenever the knob 56 is moved to its oif position shown in solid lines in FIGURE 3 and dot and dash lines in FIGURE 1. The actuating means referred to takes the form of a cam member 75 fixed to the slide 55 and having an angled surface'76 positioned to engage the arm 70 below the pin 72. The parts are so arranged that as the slide 55 is moved toward the left as viewed in FIGURES l and 3, the cam surface '76 engages the arm 76 just before the slide reaches its off position. As the slide moves to its off position,

' the cam surface 76 moves the lower end of the arm 70 rearwardly, tilting the upper end of said arm forwardly,

to thereby move the lamp and reflector assembly 66 to its retracted inoperative position shown in solid lines in FIGURE 3. When the knob 56 is subsequently moved toward the right from its off position, the cam surface 76 moves out of engagement with the lower end of the arm 70, and the

springs

73 and 74 thereupon return the reflector and lamp assembly 66 to the operative position shown in solid lines in FIGURE 2 and dot and dash lines in FIGURE 3.

The use of a thin-walled copy roll 25 and of a movably mounted lamp and reflector assembly 66 as aforedescribed permits the lamp to be positioned close to the composite and also permits rapid cooling of the parts when in shut-01f position, preventing the development of a hot spot in the roll 25 as a result of absorption of 'heat from the assembly 66 such as might occur on shutoff of the machine if the assembly 66 were fixed in its operative position. The occurrence of such a hot spot would prevent proper functioning of the machine so long as the hot spot exists, since a composite would be overheated by contact with 'the hot spot as it passes through the machine.

Energization of the lamp 68 is under the control of a normally open switch 77 (FIGURE 1) provided with a rotatable actuating rod 78 extending transversely of the frame 12. A pair of wire bails 7E9 are fixed to the rod 78, as at 86 and 81 respectively, and extend downwardly therefrom across the inlet throat 64 as shown in FIGURE 2. Insertion of a composite into the inlet throat 64 swings the balls 79 rearwardly and upwardly to non-obstructing positions, such bail movement simultaneously actuating the switch 77 to closed position permitting energization of the lamp 68. As the trailing end of the composite enters the nip of the rolls 13 and 25, and moves out of contact with the balls 7 said bails return by gravity to the position shown in FIGURE 2, and the switch 77 returns to its normally open position effecting extinguishment of the lamp 68. It should bepointed out that the lamp and switch 77 are preferably in series circuit with the main switch 60 and the source of electrical energy, so that the lamp can be energized only if the knob 56. is in one of its on positions. It is apparent, therefore, that the single control knob 56 is eifcctive to control energization of the lamp 68 and motor 29 and is additionally effective to control the speed at which the copy roll 25 is driven, as wellas the position of the lamp and reflector assembly 66.

It will be observed that the reflector 67 has a relatively narrow openingflZ which concentrates the radiant energy from the lamp 68 along a relatively narrow band of V the nip area of'the rolls 18 and 25. In the presently preferred'form 'of the invention'the reflector opening 82' ative position, and the speed with which a composite can be moved through the nip of the rolls 18 and 25 can be selectively varied from 1.25 to 4.5 inches per second depending upon the position of the control knob 56.

The reflector 67 is characterized by exceptional reflectivity, i.e. greater than 93 percent reflectance of infrared, excellent heat stability, low cost and light weight. Referring to FIGURE 4, the reflector 67 may be made of a pair of

complemental metal shells

67a and 67b, preferably of aluminum which may be formed to the desired shape by suitable machining, extrusion, rolling or other means. The inner surface 83 of the reflector 67 is overlaid with a thin layer 84 of low temperature porcelain enamel. The layer 84 may be applied by spraying the surface 83 with a thin layer of a slip comprising slurry of a low temperature frit, an opacifier, suitable suspending or binding agents and water. The frit preferred for this purpose is a substantially lead free alkali titania silicate glass of the type commercially available under the trade name 3M Brand Aluminum Frit No. 8102. The thickness of the layer of slip is preferably held within'close tolerances at 0.002 inch in thickness. The reflector 67 is then baked at the slips curing temperature, i.e. at 9701000 R, which is below the melting temperature of the aluminum base, and is then allowed to cool. The resulting enamel layer 84 is characterized by an extremely smooth surface with a high gloss. The reflector 67 is then placed in a vapor coating apparatus and a thin film of chromium or nickel containing bonding agent is vapor coated thereon. Suitable bonding agents are elemental chromium and Inconel, an alloy of iron, chromium and nickel. A thin film 85 of gold is then vapor coated onto the surface of the porcelain enamel layer 84 bearing the bonding agent, the amount of gold being preferably just sufficient to provide opacity, although slightly less or slightly more than that required for opacity may be applied. If a bonding agent is not used, the gold layer 85 may be vapor coated directly onto the porcelain enamel layer 84, and a bond therewith can be produced by a second baking operation at a temperature just below the 1000 F. softening temperature of the enamel.

The improved reflector 67 is superior to reflectors heretofore known and in particular is superior to reflectors in which the reflective material is electroplated directly onto a metallic base, since in the latter type, surface irregularities in the base are imparted to the reflective layer. In the instant reflector, such irregularities are not imparted to the surface of the enamel layer, which is extremely smooth and glossy. The porcelain enamel layer 84 provides a chemically inert and heat insulating barrier between the metal of the base 67 and the metal of the reflective layer 85 preventing chemical reaction or alloying of these metals which would deleteriously affect the reflective properties of the layer 85. Since the ceramic layer 84 maintains the barrier even at high temperatures, the reflector 67 has high temperature stability heretofore unobtainable. Moreover, the heat insulating qualities of the layer 84 prevents excessive heating of the low temperature alloy base 67.

In the operation of the improved machine, it is important that the composite lay flat against the copy roll 25 as it passes through the nip of the rolls 18 and 25.

A number of factors, however, tend to create wrinkling of the composite as it passes through the nip, such factors including embossing, letter folds, high moisture content and mill formed moisture wrinkles in the original or copy paper. Surprisingly, it has been found that by forming the copy roll 25 in a novel manner, such factors can be prevented from causing wrinkling of the composite. To this end the copy roll preferably has an average profile in axial section which is radially inwardly bowed from its ends toward the central portion thereof. The bow referred to is termed negative bow and it defined in terms of inches of external radius of the central portion of the roll less than the radius of a perfect cylinder having a radius corresponding to that of the ends of the roll inwardly of any terminal bead thereon. The average negative bow is preferably at least 0.00015 inch per inch of length of the roll 25, and 0.001 inch per inch of diameter of said roll. In the embodiment of the invention illustrated, i.e. one in which the roll 25 is 10 inches in length, and 1.780 inches in diameter at the ends, a negative bow of 0.004 inch has been found effective to prevent wrinkling of a composite passing through the machine.

What is claimed as the invention is:

1. In a thermographic copying machine having means including a roll defining a copy station, means for irradiating a composite of a graphic original and a copy sheet while in contact with said roll, said means comprising a lamp assembly, means mounting said lamp assembly for movement between an operative position closely adjacent a surface of said roll and a retracted position spaced away from said roll surface, drive means for said roll, and actuating means operatively associated with said mounting means and said drive means for actuating said lamp assembly to operative position when operation of said drive means is initiated and to retracted position when operation of said drive means is terminated.

2. In a thermographic copying machine having means including a roll defining a copy station, means for irradiating a composite of a graphic original and a copy sheet while in contact with said roll, said means comprising a lamp assembly, means mounting said lamp assembly for movement between an operative position closely adjacent a surface of said roll and a retracted position spaced away from said roll surface, drive means for said roll, actuating means operatively associated with said mounting means and said drive means for actuating said lamp assembly to opervative position when operation of said drive means is initiated and to retracted position when operation of said drive means is terminated, and

switch means operatively associated with said lamp assembly permitting energization thereof when said assembly is in operative position and preventing ene'rgization thereof when said assembly is in retracted position.

'3. In a thermographic copying machine having means including a roll defining a copy station, means for irradiating a composite of a graphic. original and a copy sheet while in contact with said roll, said means comprising a lamp assembly, and means mounting said lamp assembly for movement between an operative position closely adjacent a surface of said roll and a retracted position spaced away from said roll surface, drive means for said roll, actuating means operatively associated with said mounting means and said drive means for actuating said lamp assembly to operative and retracted positions, and manually operated control means for said drive and mounting means movable between anoff position in which it effects shutoff of said drive means and retraction of said lamp assembly and an on position in which it effects operation of said drive means and movement of said lamp assembly to operative position.

4. A machine according to claim 3 in which there is switch means for said lamp assembly also under the control of said manually operated control means and operable to prevent energization of said lamp assembly when said control means is in off position and to permit energization of said lamp when said control means is in on position.

5. In a thermographic copying machine having means including a roll defining a copy station, means for irradiating a composite of a graphic original and a copy sheet while in contact with said roll, said means com prising a lamp assembly, and means mounting said lamp assembly for movement between an operative position closely adjacent a surface of said roll and a retracted position spaced away from said roll surface, variable speed drive means for said roll, manually operated control means movable between an off position and a plurailty of on positions operatively associated with said drive means for selectively means or driving of said roll thereby at a selected speed, and actuating means for said mounting means opera= tively associated with said control meanstto move said lamp assembly to retracted position on movement of said control means to off position and move said lamp assembly to operative position on movement of said control means to an on position. t i

6. A thermographic copying machine comprising means including a tubular cylindrical radiant energy transmissive roll defining a copy station, means for irradiating a composite of a graphic original and a copy sheet while in contact with the outer surface of said roll, said means comprising a lamp assembly extending longitudinally within said roll, means mounting said lamp assembly for movement between an operative position closely adjacentv the inner surface of said roll and a radially inwardly retracted inoperative position, drive means for rotating said roll, and single control means which effects movement of said mounting means to retract said lamp assembly to said inoperative position and which terminates operation of said drive means.

7. A thermographiccopying machine comprising means inner surface of said roll and a radially inwardly re- 'tracted lnoperative position, and single control means which effects movement of said'mounting means to retract said lamp assembly to said inoperative position and which terminates operation of said drive means.

8. A thermographic copying machine comprising a effecting shutoff of said drive tubular cylindrical radiant energy transmissive roll, means for conveying a composite of a graphic original and a copy sheet to and from a copy station at which said composite is pressed thereby into intimate contact with a narrow axially extending outer surface portion of said roll,

, operative position closely adjacent the inner surface of said roll and at which the radiation from said lamp is focused on said narrow outer surface'portion'of said roll and a radiallyinwardly retracted inoperative position, and single control means which etects movement of said mounting means to retract said lamp assembly to said moperative position and which terminates operation of said conveying means.

9. A thermographic copying machine comprising a tubular cylindrical radiant'energy transmissive glass first roll, drive means for rotating said first roll, a relatively soft resilient second roll parallel withand in deformed.

pressure contact with said first roll, difining therewith a narrow axially extending nip area, means for irradiating a composite of a graphic original and a copy sheet compressed against said first roll in said nip area comprising a lamp assembly extending longitudinally within said first roll, deflector meansfocusing' the radiation from .said lamp assembly within a narrow region, means mountmg said lamp assembly for movement between an operative position closely adjacent the inner surface of said roll and at which the radiation from said lamp is focused on said nip area and a radially inwardly retracted. inoperative position,-and single control means which effects movement of said mounting means to retract said lamp assembly to said inoperative position and which terminates operation of said drive means.

10. A thermographic copying machine comprising a tubular cylindrical radiant energy transmissive glass roll, means for conveying a composite of a graphic original and a copy sheet to and from a copy station at. which said composite is pressed thereby into intimate contact with a narrow axially extending outer surface portion of said roll, means for irradiating said original at said copy station comprising a lamp assembly extending longitudinally within said roll, reflector means positioned with respect to said lamp for focusing the radiation from said lamp assembly along a narrow band, means mount ing said lamp assembly and reflector means for movement relative to said roll between an operative'position closely adjacent the inner surface of said roll and at which the narrow band of radiation is focused on the outer surface portion of said roll and an inoperative position spaced radially inward from the surface of said roll at which the narrow band of radiation is not focused along any portion of said roll, and control means for said drive and mounting means movable between an off position in which it eiiects shutoii of said conveying means and retraction of said lamp assembly and an on position in which it effects operation of said conveying means and movement of said lamp assembly to operative position.

11. A thermographic copying machine comprising a copy roll adapted to havea composite of a graphic original and a copy sheet moved therepast in contact with the periphery thereof; said copy roll being generally cylindrical in shape and having an average profile in axial section which is radially inwardly bowed from its ends toward the central portion'thereof, and means for pressing a composite against the periphery of said copy roll as said composite moves therepast, the contour of said copy roll tending to prevent wrinkling of a composite vmoved therepast and in pressure contact therewith under the influence of said pressure applying means.

12. A thermographic copying. machine comprising a copy roll adapted to have a composite of a graphic original and a copy sheet moved therepast in contact with the periphery thereof, said copy roll being generally cylindrical in shape and having arr average profile in axial section which is radially inwardly bowed from its ends toward the central portion thereof, the amountof said bow being at least 0.00015 inch per inch of length of said roll and 0.001 inch per inch of diameter of said roll, and means for pressing a composite against the periphery of said copy roll as said composite moves therepast, the contour of said copy roll tending to prevent wrinkling of a composite moved therepast and in pressure contact therewith under the influence of said pressure applying means.

References tilted in the file of this patent UNITED STATES PATENTS Gulko Mar. 19, 1963

Claims

1. IN A THEREMOGRAPHIC COPYING MACHINE HAVING MEANS INCLUDING A ROLL DEFINING A COPY STATION, MEANS FOR IRRADIATING A COMPOSITE OF A GRAPHIC ORIGINAL AND A COPY SHEET WHILE IN CONTACT WITH SAID ROLL, SAID MEANS COMPRISING A LAMP ASSEMBLY, MEANS MOUNTING SAID LAMP ASSEMBLY FOR MOVEMENT BETWEEN AN OPERATIVE POSITION CLOSELY ADJACENT A SURFACE OF SAID ROLL AND A RETRACTED POSITION SPACED AWAY FROM SAIF ROLL SURFACE, DRIVE MEANS FOR SAID ROLL, AND ACTUATING MEANS OPERATIVELY ASSOCIATED WITH SAID MOUNTING MEANS AND SAID DRIVE MEANS FOR ACTUATING SAID LAMP ASSEMBLY TO OPERATIVE POSITION WHEN OPERATION OF SAID DRIVE MEANS IS INITIATED AND TO RETRACTED POSITION WHEN OPERATION OF SAID DRIVE MEANS IS TERMINATED.

11. A THERMOGRPHIC COPYING MACHINE COMPRISING A COPY ROLL ADAPTED TO HAVE A COMPOSITE OF A GRAPHIC ORIGINAL AND A COPY SHEET MOVED THEREPAST IN CONTACT WITH THE PERIPHERY THEREOF, SAID COPY ROLL BEING GENERALLY CYLINDRICAL IN SHAPE AND HAVING AN AVERAGE PROFILE IN AXIAL SECTION WHICH IS RADIALLY INWARDLY BOWED FROM ITS ENDS TOWARD THE CENTRAL PORTION THEREOF, AND MEANS FOR PRESSING A COMPOSITE AGAINST THE PERIPHERY OF SAID COPY ROLL AS SAID COMPOSITE MOVES THEREPAST, THE COUNTOUR OF SAID COPY ROLL TENDING TO PREVENT WRINKLING OF A COMPOSITE MOVED THEREPAST AND IN PRESSURE CONTACT THEREWITH UNDER THE INFLUENCE OF SAID PRESSURE APPLYING MEANS.