US2308130A - Reproducing apparatus for light sensitive reproduction media - Google Patents

Description

JUL 12, 1943. F. w. voN MEISTER ErAL 2,308,130

REPRODUCING APPARATUS FOR LIGHT SENSITIVE REPRODUCTION MEDIA /2/ ,a l l INVENTORS TH EIR ATTORNEYS Jah. 12, 1943. F. w. voN MEISTER HAL 2,308,130

REPRODUCING APPARTUS FOR LIGHT SENSITIVE REPRODUCTION MEDIA Filed Feb. l, '1939 8 Sheets-Sheet 2 Frederiks/r M 2.21971. Mea-te OM n t am 5 Mvv. 5 Am a m w.. n m m T i n .e m m m w W T Jn- 12, 1943. F. w. VON MEISTER ET AL 2,308,130

REPRODUCING APPARATUS FOR LIGHT SENSITIVE REPRODUCTION MEDIA Filed Feb. l, 1939 8 Sheets-Sheet 3 @las Fredemc/r I4( von Malte/er Fredem'c/r W. Andrey INVENTORS THEIR ATTORNEYS Filed Feb. l, 1959 8 Sheets-Sheet 4 ,EW 6 49 ai@ l l l I l l l l l l l uml- F/'edewLc/r l/l( von Master Fede'rL'c/f' V14 Andrew INVENTORS TH El R ATTORNEYS Jan- 12, 1943. F. w. voN MEISTER ETAL 2,308,130

REPRODUCING APPARATUS FOR LIGHT SENSITIVE REPRODUCTION MEDIA Filed Feb. l, 1939 8 Shee'tS-Sheet 5 lll /43 ou Frederick M von Mezlater Frederzlck IV. Andrew `INVENTOR5 THEIR ATTORNEYS Jan. 12, 1943. F. w. voN MEISTER ETAL 2,308,139

REPRODUCING APPARATUS FOR LIGHT SENSITIVE REPRODUCTION MEDIA Filed Feb. l, 1939 8 Sheets-Sheet 6 Fredemck I4( Vani/Mendez Frederick W. Andrew INVENTORS BY @M55 Q THE! R ATTORNEYS Jam 12, 1943- F. w. voN MEISTER ETAL 2,308,130

REPRODUCING APPARATUS FOR LIGHT SENSITIVE REPRODUCTION MEDIA File Feb. 1, 1939 8 sheets-sheet 7 Wyo 114 a EW j@ ump' IIIIIIII IIIIIHHIII INVENTORS TH EIR ATTORNEYS Jan. 12, 1943. F. w, voN MEISTER ETAL 2,308,130

REPRODUCING APPARATUS FOR LIGHT SENSITIVE REPRODUCTION MEDIA Filed Feb. l, 1939 8 Sheets-Sheet 8 Wzg 2@ Fredom'ck IM 'von MeIlser /J' Frederalck I4/. And/few INV ENTO R5 BYML QL* TH EIR ATTORNEYS Patented Jan. 12, 1943 REPRODUCING APPARATUS FOR LIGHT SENSITIVE REPRODUCTION MEDIA Frederick W. von Meister, New York, and Frederick W. Andrew, Glen Head, N. Y., assignors, by mesn'e assignments, to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware Application February 1, 1939, Serial No. 253,956

8 Claims.

The invention relates to reproducing iparatus for light-sensitive reproduction media, particularly that type of reproduction media which reproduces positive copies from positive originals and which is developed in a dry state by exposure to a gaseous developing medium.

Reproduction media of this kind are known as diazotype layers. They are produced by treating the surface of a suitable base, generally paper, with a solution of two dye components, one of which is a light-sensitive body called the diazo component and the other, which is called a coupling component, is a compound capable of reacting, under suitable conditions, with the diazo component to form a dye. The diazo component of such a light-sensitive layer is most sensitive to light emission between the 3600 to 4200 line. Such rays effectively decompose the diazo component, so that it can no longer combine with the coupling component to form a dye. Thus. when a diazotype layer is exposed, under an original tracing, design, printed sheet or other work piece to be copied, to a source of light furnishing rays in the '3600 to 4200 line, the diazo component, in those areas which are not protected by the solid lines of the tracing, or design, or letters of the printed sheet, is decomposed. Upon subsequent development, a dye forms only in the areas which were protected from the iight by the solid lines of the tracing,

or design, or letters of the printed sheet. Those areas which were unprotected and, hence, exposed to light, will be colorless, and thus the design of the original will be reproducedin color, on a colorless background. Since development of these diazotype light-sensitive layers is effected by contacting the exposed reproduction with a gaseous developing medium, such as ammonia gas, out of contact with any moisture, no shrinking occurs and an exact dimensional replica is obtained from which true readings can be taken.

It has been suggested. in connection with some types of photoprinting apparatus, particularly the type using .so-called blue print paper as the light-sensitive medium. to thread a continuous web nf the licht-sensitive medium through the train of apparatus including the printer, Washers and driers (which latter, in the case of blue print paper, constitute the developer). The disadvantage of such continuous blue print machines and developers lies in the waste of blue print paper at the trimming end of the machine, where the continuous web of finished prints is trimmed by hand to the size of the drawing which has been printed thereon. Such trimming by hand is not very neat and consumes much time and causes waste. Where quantity production at high printing speeds is involved and when the drawings to be printed are not of the full width of the sensitized paper web, it is impossible to cover the entire surface of the sensitized material when using a continuous web. Obviously, substantial quantities of the sensitized paper are Wastedbetween 20% and 30% is frequently experienced. It has recently become the tendency of the engineering profession to Standardize the size of drawings, thereby making it practical to use sensitized materials in sheet form cut to the dimensions of the standard sized drawings. With wet or moist developing processes, as in the case of blue print paper, the'handling of such cut sheets through the developing baths or machines involves diiliculties. In the case of the diazotype dry developing process, the handling of cut sheets from the exposing machine or printer to the developing machine is more feasible and practical at ordinary printing speeds: However, when large production at relatively high printing speeds is required, the separation of the original drawing from the exposed cut sheet of diazotype paper and the delivery of the latter to the developer presents a diiiicult problem in handling for the operator feeding the printing machine. It is, therefore, an object of this invention to provide a means for automatically separating the original from the reproduction or diazotype copy.

Many and various sources of light have been suggested and used in the past for the exposure of light-sensitive reproduction media. At rst, when blue print paper began to be widely used for making photoprint copies of drawings and other records, the necessary exposure to light was accomplished in sun or daylight by the use of sunframes. With the ever increasing volume of such work, due to industrial development, this type of exposure was soon discarded as `too slow and unreliable. Artificial sources of light were sought. Incandescent lamps were used, but in order to raise the light emission of such lamps in the 3600 A.-4200 line, to which both blue print solutions and diazo compounds are mainly sensitive, it is necessary to operate them at higher voltages than bulb life considerations permit. Furthermore, the light emitted by the incandescent lamps is particularly rich in wave lengths over the 4000 A. line, which are of no use for the purpose whatever. It, therefore, is a wasteful source to use both from the standpoint of current consumption and replacement. The carbon arc lamp, especially of the enclosed type, and the low pressure mercury vapor tube were found to emit a satisfactory amount of those rays to which blue print paper and diazotype papers are sensitive. Both of these light sources have been used for many years for the exposure of these sensitized materials. Both have definite disadvantages. The carbon arc emits light from a relatively small point and, therefore, must be placed at an appropriate distance from the sensitized material to attain equal light distribution over the entire surface which is to be exposed. Where a number of carbon arcs are installed, the problem of even light distribution is even more cornplex. In exposure units employing revolving light transmitting cylinders having arc lamps located inside the revolving cylinder, the arc lamp must be of small structural size and have short carin the accompanying drawings,

1 broken away, to more clearly illustrate the printer bons and the cylinders must be of relatively large diameter to accommodate not only the are lamps but also the automatic electro-mechanical cary bon adjusting mechanisms. Since light intensity,

at the point of use, varies inversely as the square of the distance, it is obviously a disadvantage to have to surround the source of light with a cylinder of large diameter. With these disadvantages of prior exposure machines in mind, it is a further object of our invention to provide a source of light within a glass cylinder of small diameter, which source of light will distribute rays of equal intensity over the entire surface of said cylinder.

Various devices for carrying excess heat developed by the light source away from the glass cylinder or envelope containing the light source have been suggested. These known devices consist, for the most part, of ordinary propeller blade fans positioned at one end of the light chamber. Deection fins are sometimes used to insure proper circulation of the cooling air coming from the fan. Due to the intensity of the heat developed when enclosures of small diameter are used, these methods of cooling have proven inadequate. When a sufficient volume of air is blown through the light chamber to maintain acceptable temperatures on the printing surface, that is, temperatures that would not adversely aiect the chemicals used, for instance, in drydeveloping dazotype papers, then the light source becomes overcooled, resulting in a marked decrease in the intensity of the light emission. It is, therefore, still a further object of our invention to provide a means of cooling the printing surface of vthe light chamber suficiently to maintain satisfactory printing temperatures without cooling the light source below its efficient operating temperature.

It has been found that printing media of the diazotype are susceptible to temperature differentials. Thus, if one end of the printing surface becomes appreciably cooler than the other, the printing speed at the cool end will be slower than it is at the warm end. This condition obtains in spite of the fact that the light intensity may be uniform over the entire printing surface, since the decomposition of the diazo compound by the light is favored by heat. Unless, therefore, approximately even temperatures can be obtained over the whole printing surface, uneven exposure will be the result. It is, therefore, another object of this invention to provide cooling means which will cool the entire surface to approximately the same temperature.

These and other objects are accomplished by the machine hereinafter more fully described and mechanism.

Figure 2 is a front view of the lower portion of the printer.

Figure 3 is a detail sectional view of electrical connections for the lamp showing blower ducts.

Figure 4 is a detail view of the left upper portion oi Fig. 3, showing the movable shade adjustment mechanism in section.

Figure 5 is a side view taken on line 5-5 of Fig. 3, showing shade assembly and adjustment mechanism and rack.

Figure 6 is a detail view of the electrical terminals within the lamp housing.

Figure 7 is an end sectional view of an alternate printer assembly, showing a cylindrical envelope for the light source.

Figure 7a is the same view as Fig. 7, but showing a curved envelope for the light source.

Figure 8 is a part sectional view, showing the relation of the pick-off i-lngers with the print cylinder.

Figure 9 is a top view of Fig. 7, with the section enclosed in line @-9 removed.

Figure 10 is a sectional view through line Ill-IB of Fig. 3, showing wheel attachment to lamp assembly for removal thereof.

Figure 11 is a top view of the tracks or guides at the left end of the glass cylinder.

Figure l2 is a top view of the tracks or guides at the right end of the glass cylinder.

Second modification Figure 13 is a sectional end view of the interior of the machine.

Figure 14 is an end view of the drive mechanism for this modification.

Figure 15 a fragmentary front sectional view of the suction roller used in this modification at the drive end.

Figure 16 is a fragmentary top sectional view of Fig. 15.

Figure 17 is a side view of Fig. 15 on line l1-|1.

Figure 18 is a front elevation of this modification with parts shown in section.

Figure 19 is a detail drawing of the blower ducts and lamp connection at one end of the printing cylinder.

Figure 20 is an enlarged detail drawing of the mechanism for adjusting the position of the movable light shield.

These illustrations constitute two complete modications of the invention. Figures 1 to 6 and 8 to 12 constitute one complete assembly which is conveniently designated as modification I, while Figures 13 to 20 constitute another which is designated as modification II. Figures 7 and 7a represent alternate printer assemblies that can be substituted in either modification I or II. Modification I is our preferred modification, to which particular Vreference is had in the following description. The structural distinctions between the two modifications will be pointed out at the end of the detailed description of the preferred modification. Common elements are designated by like characters in the various views.

Referring now to the machines illustrated in these drawings, the character C designates a casing of any suitable structural material which encloses the machine as a whole. The character A designates generally the printing portion of the mechanism, and the character B the developing portion thereof. The actual printing or exposure area of portion A consists of an outer revolvable glass cylinder of relatively small diameter, an inner stationary glass cylinder 2| of still smaller diameter, and a single high pressure mercury vapor arc tube 22 with self-starting activated electrodes. These' two concentric glass cylinders and the mercury vapor tube which they encompass may be of any desired length, depending upon what type ofv work is to be handled by the machine. However, it is desirable and advantageous to have the mercury vapor tube and glass cylinders not less than long, in order to equip the machine for the handling of wide rolls of printing media as well as small cut sheets. In the illustrated modifications of our invention, the exposure or printing assembly is designed to accommodate a 46" lamp. In the space between the inner and outer glass cylinders are positioned two light shields. One of these is a stationary fixed shield 23 which covers the throat of the vprinting cylinder, thus protecting the light-sensitive materials from premature exposure and the operator from the intense glare of the light,

Well as by speed control, to control the total amount of light reaching the printing surface for exposure. As is illustrated in Fig. 3 and in detail in Figs. 4 and 5, the stationary shield 23 is rigidly affixed to the inner lamp housing 25 at each end of the glass cylinder 20 by means of a pair of angle members 26. These angle members also serve to support the guide 21 for the sliding or adjustable shield 24. To the outer surface of the sliding shield at each end is attached a block member 28 which carries rigidly aixed thereto a plate member 29. Each plate member has affixed to its outer extremity a curved rack 30, which engages a pinion 3i attached by means of collar 32 and set screw 32a to a bar 33, which latter extends through the outer lamp housing 34 and carries on its outer extremity still another pinion 35. This outer pinion engages rack 35, which is attached through rod 31, to a manually operated knob 38. A stop collar 39 is provided on rod 31, to prevent pulling the rack 38 off the pinion 35. Removable link 39a allows for conveniently removing the rack within the lamp assembly.

Lamp assembly and electrical connections The burner or lamp assembly for this machine consists of a 46" quartz envelope high pressure mercury vapor arc tube 22 having self-starting activated electrodes, which has its electrode extremities embedded in receptacles 40. Surrounding the electrodes are metal envelopes or tubes 4|. which are separated from the electrical connections by insulators 42. These metal envelopes serve to prevent excess cooling of the electrodes. At either end of the lamp assembly (Figs. 3 and 6), the electrodes are connected With the current source by means of a slip receptacle 44 which consists of a prong or male member 45 which ts tightly into a tong or female member 43. The prongs 45 are connected to the respective electrodes, while the tongs 43 are connected to the current source. The wires leading to the tongs 45 are carried to the outside of the machine through insulator 46, the latter being journaled in the outside housing plates 48 and 55, respectively, by means of packing ring 49. At one end of the lamp (left side of Fig. 3), the wire 41 connected to tong 43 is carried through a pipe 5l, bent in the shape of a handle to a slip connection 50 in a. terminal box 5|, mountedlon the air duct 52. An electrical housing 54 containing insulator 56 is attached to the terminal end of the bent pipe 5I, thus insuring safe and rigid contact of the slip connection 50.

In order to facilitate removal of the burner or lamp assembly, Wheels 51 ,are provided at either end of the lamp, suspended on carriages 58, which are mounted onthe bottoms of the inner housing 25. At the left end (Fig. 3) of the burner assembly, the wheel carriage 58 is held rigid by a bar member 59 affixed to the removable plate 55. To remove the entire burner assembly, then. it is only necessary to remove the two screws 60, which hold the removable plate 55, to the outer housing 34 and pull the bent pipe handle 53 to the left. This will break the electrical connection at the right end slip contact 44 and left end slip contact 50, and even if the operator had neglected to open the switch of the main supply line, there would be no danger of injury by shock. The wheels 51 will engage guide tracks 52 and 63 provided at either end of the outer glass cylinder. When the wheels at the right side of the assembly reach the edge of the outer housing 34 at point X, they leave the guide tracks 63 and travel along the inner surface of the outer glass cylinder until they reach the left end thereof, at which point, Y, they engage the guide tracks 62 provided on that side of the assembly. As shown in detail in Fig. 10, it is preferable to have two sets of wheels 51 at each end of the assembly and, as shown in Fig. 12, it is preferable to provide a wide opening to the guide tracks 63 at the right end of the assembly, to insure easy engagement of the wheels 51 with the tracks 63 upon leaving the glass cylinder when returning the assembly to position.

Cooling of the burner The system designed for cooling the outer revolving glass cylinder and the inner stationary glass cylinder provides for alternately injecting air through the burner assembly, rst from one end and then from the other. This provision allows for maintaining a uniform temperature over the surface of the revolving glass cylinder. It also equalizes the temperature of the tube so as to lessen the chances of uneven light emission or thermal stresses on the tube seals and walls. Provision is also made for metering only enough air into the stationary inner glass cylinder and, hence, around the mercury vapor arc lamp, to cool the lamp down to its critical temperature. By critical temperature, we mean that temperature in the temperature-light intensity curve of the lamp below which the light intensity drops off rapidly and, hence, below which only minor decreases in temperature, by cooling, will cause substantial losses in intensity. This rapid loss in intensity by cooling is caused by a drop in the mercury vapor pressure, due to the lowering of the temperature of the envelope of the lamp. This system of cooling the lamp and printing surface, which consists of the following cooperating elements illustrated in our preferred embodiment, allows for placing the print to be exposed mueh closer to the source of light than has heretofore been possible: A blower 64, having air vintake 65 and air lter 66, is driven from motor 51. This blower forces air into the main air duct 68 and thence into one or the other of the branch ducts 69 and 10. An alternating or flip valve 1I directs the flow of air. In the position shown in Fig. 2, the air will be directed to the left branch-duct 69. This flip valve 1I is caused to change its position so as to first cut off one branch duct and then the other by a Geneva movement 12, which is actuated from the blower drive shaft 13 through reduction gears 14 and shaft 15. Thus, as the disc 16 carrying arm 11 is revolved slowly in a clockwise direction, the pin 18 will disengage slot 19 and will next engage slot B as the disc 16 continues to revolve clockwise. In the downward stroke, being thus engaged with the slot 80, the arm 11 and pin y18 will pull the flip valve through an angle of 90 which obviously shuts o the left hand branch duct 69 from the blower, and opens up the right hand branch duct 1B. The next revolution of the disc again opens up the left duct 69 and closes the right duct 10, and so on. The blower 64 operating through this alternating valve arrangement is so dimensioned that a reasonably high static pressure is generated in the air ducts. The greater portion of the air coming from the one branch duct 52 or the other, B I as seen in Fig. 3, enters the space between the outside of the stationary inner glass cylinder 2l and the inside of the outer revolving glass cylinder 28. A small portion of the air is metered into the space between the mercury vapor tube 22 and the inside of the inner glass tube 2l through the metering holes 1la, provided in the inner housing 25. The heated air in any given cycle of the circulation passes out of the burner assembly into the branch duct opposite to the one through which the cool air has entered. Thence, it is carried out through outlet 8|.

When mercury vapor arc tubes of lesser intensity are used in place of the high intensity tubes particularly described herein, it is possible to either seal the tube within the inner glass cylinder and ll the space around the tube with an inert gas or to merely mount the tube within the inner glass cylinder after the manner shown in the drawings, but omitting the metering holes 11a. In either case, the tube will be completely enclosed in a jacket and there will, therefore, be no circulation of the cooling media in the space between the tube and the inner glass cylinder. Since the air or other inert gas occupying the completely enclosed space surrounding the mercury vapor arc tube is static or does not become changed during the operation of the machine, cooling is effected by radiation of the heat to the inner glass cylinder and removal of this heat by blowing air across the outer surface of the inner glass cylinder. The circulation of air across the outer surface of the inner cylinder, that is, through the ring-shaped space between the inner cylinder and the outer revolving cylinder may be effected by 4alternately reversing the current of air as described above or if the path of travel from one end of the outer cylinder to the other is sufciently short to insure that the temperature gradient between the left and right ends of the cylinder is not great enough to make any appreciable difference in printing speed, then the cooling air may be blown through continuously in one direction.

We have found that in using the long high pressure mercury vapor lamp which combines the advantages of high intensity, even light emission over the entire width of the sensitized material, and close proximity 0f the light source to the material to be exposed', it is essential that the inner stationary glass cylinder arrangement be lines.

used in connection with the mercury vapor lamp, since the mercury Vapor arc is a source of powerful radiation over a Wide band of the spectrum. Only a small portion of this band is required and needed for the printing of diazotype and similar light-sensitive materials. This band, as explained above, is between the 3600 A. and 4200 The balance of the radiation of the light source is not required for printing, and since the quartz envelope of the lamp transmits a very wide range of this radiation and also those rays which cause sunburn, a glass is used for the inner as well as the outer revolving cylinder vwhich will absorb the harmful rays and only transmit a large portion of the rays which are needed for printing. Glass that would only transmit from 3600 A. to 4200 1s not readily available without the use of complicated filter glasses. Since glass absorbs a large proportion of the radiation which is transmitted through the quartz wall of the tube, this radiation is converted into heat in the glass cylinder. Without an inner glass cylinder or jacket, this absorption and conversion to heat takes place in the outer rotating glass cylinder. We have found that, if the outer cylinder is kept small enough in diameter to make the best use of the laws of light, then the inner surface of the outer rotating glass cylinder is insufficient surface of attack, to remove all the heat which is generated by absorption and, thus, the outer glass cylinder without the use of an inner cylinder becomes too hot for printing purposes. By introducing the inner stationary glass cylinder, most of the absorption of the unwanted emission takes place there and the outer glass cylinder does not get excessively hot, provided that a lively stream of air is passed over the outer surface of the inner cylinder and the inner surface of the outer cylinder. These considerations allow of the use of mercury vapor lamps which, insofar as present experiments have shown, have an input of up to 100 watts per inch of active length. Such lamps give, under proper conditions of pressure and temperature, between 40 and 50 lumens of radiant energy per watt input, whereas the low pressure mercury vapor lamps which have been used to date will only give about 20 lumens per watt. With an input of 77 watts per inch active length (for a total burner capacity of 3542 watts), we have found that when using a 41/4" outside diameter revolving glass cylinder, printing speeds are attainable which are faster than speeds obtained on modern arc lamp equipped printing machines using three times the amount of electric energy.

Drive mechanism and delivery of print subject to printer The revolving outer glass cylinder 20 rotates on roller supports 82, which are freely suspended on brackets 83 attached to the two end plates 84 of the machine. A series of flexible endless belts 85, which are held tightly against the outer glass cylinder 20, serve to drive the said cylinder and to convey the print subject around the printing surface of the outer glass cylinder. These endless belts 85 encompass about 2/3 to 3A of the periphery of the glass cylinder 20, thus forming an open throat facing the operator. As explained above, a stationary light shield 23 is provided inside the outer glass cylinder to prevent light emission from this throat, thereby protecting the operator from harmful light rays and preventing premature exposure of the light-sensitive paper at the bottom of the throat. The endless belts ascenso 85 are held in position by two front idler pulleys 86 and a rear idler pulley 81, also idler pulleys 88 and 89 and a drive roller 90. Two additional idler pulleys 9| and 92over the drive roller serve to insure maximum surface contact of the drive roller 90 by the endless belts 85. The tension in the endless belts 85 may be regulated by adjustlng the position of the rear idler pulley 81 by means of adjustment screw 93, which acts through lever arms 94 and 95. The drive roller 90 is driven by a belt 96 from the drive shaft of a variable speed regulator 91, which is driven by the motor 61. A manually operated cable drive 98, attached at one end to the speed regulator 91 and at the other to a wheel 99, enables the operator to change the printing speed at will.

A separate or auxiliary set of endless belts |00, which are driven from drive roller and are held in position by idling rollers |02 and |03 and tensioning roller |04 assist in conveying the print work from the operators platform to the entrance of the printer.. These auxiliary belts also carry the vfinished print and original from the printer to a perforated evacuated separating drum |06. A belt |01, taken from the drive roller 90, drives roller |08 mounted on the developing portion B of the machine and a belt from roller |08 to the drive roller |09 of the developer drives the drum H0, which carries the exposed print through the developing chamber of said developing portion B. A gear wheel ||2 mounted on the end of the developer drum drives gear ||3 in a clockwise direction. This gear ||3, therefore, drives gear ||4 in a counter clockwise direction which, in turn, drives gear ||5 in a clockwise direction. This last gear ||5 meshes with a gear wheel ||6 mounted on the separating drum |06 and, hence, drives the said separating drum in a counter clockwise direction.

The tension of the auxiliary belts |00 is regulated by adjustment screw ||1, which acts through lever arms ||8, I9, and |20, to pull tensioning roller |04 either forward or backward.

It is often necessary to clean the outside of the outer glass printing cylinder 20 and, since the throat opening of the said printing cylinder is too small to allow access for cleaning purposes, we have provided a mechanism for lowering the front portion of the endless conveyor belts and 4raising the front portion of the auxiliary belts |00. This mechanism consists of a pedal |2| running across the front of the machine and mounted on arms |22, an upright member |23 carrying the rack teeth |24 which engage pinion |25. Said upright member |23, being connected to the shaft of idler |26, will pull that roller down when the pedal |2| is depressed. This will let the conveyor belts 85 drop. The gear |25 and rack |24 act to prevent too quick a drop of idler |26, and the stop arm |21 connected to spring |28 prevents the idler |26 and conveyor belts 85 from dropping by their own weight. A pin connection 500 pivotally connecting an arm |29 to upright member |23, acts to pull said arm |29 down and forward when the pedal is depressed. thus tending to pull the elbow member |3| down and backward, which forces the idler |02 up and forward carrying the auxiliary belts |00 with it. Thus, a good portion of the front of the outer glass cylinder 20 is exposed for cleaning or such other adjustments as may be necessary. By depressing the pedal a little, it is also possible to relieve the pressure between the contact portions of the conveyor belts 85 and auxiliary belts |00 leading to the printer, thus to enable the operator to adjust the position of the work piece just before it enters the printer.

Print separating means The automatic separating roller |06 is in the form of a cylindrical shell having a series of perforations |32 through the shell and extending around the periphery thereof. A shield |33 ci some flexible non-porous material, such as oil cloth, is suspended within a frame |34 around the back half of the perforated cylinder. Upon evacuating the air from the inside of the perforated cylinder |06, this shield |33 will be drawn up against the outer surface of the cylinder, thus cutting off the perforations in the back half of the cylinder. Due to the flexible nature of this shield and the fact that it is freely suspended from the top, it will permit the perforated roller to slip aroundfreely. The perforations on the front half of the cylinder being open will draw in air and, hence. suck the exposed print coming from the printing cylinder 20 firmly against the perforated roller |06. The original tracing or other work piece that has been copied being unaffected by the suction of the perforated roller |06 will fall into the trough |35 provided therefor.

A series of endless belts |36 formed of endless springs engage the front half of the perforated cylinder |06 in channels |31 provided therefor in the said perforated cylinder. These endless belts, being driven frictionally by the perforated cylinder |06, travel around pulley |38 and the idler 89 of the main conveyor belts. The section of the endless belts |36 between roller 89 and the perforated cylinder |06 cooperates with the auxiliary belts |00 to aid in conveying the exposed print and original away from the printer. The section of the endless belts |36 between the perforated cylinder and the top pulley |38 serves as a means to lift the exposed print off the perforated roller |06 thereby breaking the vacuum and transport or guide it to the entrance to the developer B. While on .this section of the endless belts the exposed print is in full view of the operator, thus enabling him to observe the degree of exposure and make any alteration in printing speed that may appear necessary.

The automatic separating roller |06 is exhausted by means of exhauster blower |56, the air being withdrawn through branch ducts v|51 and |58. The main exhauster duct |59 collects the air from these branch ducts and delivers it to the blower |56, which expels it through exhaust duct |60. The common shaft 13 of the exhauster glower |56 and cooling blower 64 is driven from the motor 61 by means of pulleys |6| and |62 and belt |63. It is also possible to exhaust the automatic separating roller by mounting independent exhauster blowers on either end of the perforated cylinder. This alternative method will be treated below in describing modification II with reference to Fig. 18.

Paper guide and pick-ofi The idler roller |03 is madeup of three distinct parts, as shown in detail in Figs. 8 and 9. There is an inside stationary shaft |39 around which are provided freely rotatable self-lubricating bearings |40 and steel rings |4|, spaced at intervals along the shaft, which spacing coincides with the spacing of the endless auxiliary belts |00. Between each assembly of such bearing and steel ring and adjacent the outside edge of each end assembly, there is a plate member |42 fitted around the shaft |39. These plate members |42, which serve as bearing surfaces for the ends of steel rings |4| and self-lubricating bearings |40, are rigidly aixed to a channel member |43, by means of set screw |44, which extend into the outer surface of the shaft |39. Y The channel member |43 extends from. one end plate of the machine to the other, to which end plates it is appropriately aflixed. The bottom and inside edges of plate members 42 are shaped to follow the curvature of the idler |26 and the outer glass cylinder 20, respectively. This shaping of the plate members |42 forms a nipple |45, which helps to guide the work piece to be printed on to the outer glass cylinder 20, in correct position for printing. A rod |46 extends through a protruding portion |41 of the plate members |42, from one end plate of the machine to the other. Spaced between the plate members |42 on this rod |46 is a series of finger members 48 which are free to rotate on the rod |46 and have their other ends curved to nt against the outer surface of glass cylinder 20. Wire springs |49, one end of which is embedded in the finger members |48 and the other in the rod |46, are provided to hold the ngers taut against the surface of the glass cylinder. We prefer to make these ngers 48 of a suitable synthetic resin. However, as an alternative construction (not illustrated) for these pick-off fingers, we may have a thin flexible steel plate attached to the tips of plate members |42 and extending the length of the rotating cylinder. This thin steel plate is slotted on the side next to the glass cylinder, to form fiat steel fingers. The spring action of the steel plate itself holds these fingers taut against the surface of the cylinder. In view of the fact that these finger members |48 are free to rotate on the bar |46, except forthe tension of the wire spring |49, they will ride over any imperfection in the surface of the glass cylinder 20 without any trouble. Hence, the glass cylinder does not have to be ground perfectly, nor does it have to rotate perfectly.

As the work piece including the original and print emerges from the exit side of the printer, the ngers |48 will pick it off the glass cylinder and guide it to the auxiliary belts which, with the aid of the upper portion of the main conveyor belts 85 and the endless spring belts |36, will convey it to the automatic separator described above.

The developer section The developer section B of this machine consists of a drum type ammonia gas developer for the dry development of diazotype light-sensitive prints. Such a developer is described in detail in our copending application, Ser. No. 215,416, filed June 23, 1938. In the modification shown herein (Fig. 1) the developing chamber is formed by the housing |50 which may be lined with a suitable insulating material |5| to aid in preventing the condensation of the gaseous developing medium. Suitable guiding means, indicated schematically in Fig. 1 of the drawings at |52, may be provided to hold the print in position against the surface of revolving drum ||0 while it conveys said print throughthe developing chamber. Suitable heating means (not illustrated) are also provided in the developing chamber close to the surface of the revolving drum at intervals around its periphery, in order to deter condensation of the developing medium on the exposed print.

'I'he print to be developed is delivered to the developer from the automatic separator |06, lby the belts |36. It is picked up by the revolving drum ||0 and guide roller H3. After passing the guide roller H3, it engages the rollers |52 and travels along the periphery of the drum ||0 under the said rollers |52. At the exit of the developing chamber, the guide roller |53 engages the developed print and delivers it to the exit chute |54. Curved plate |55 is provided, in order to pick the print off the revolving drum in case it does not drop off after passing the 'guide roller.

M odz'flcation II The modification of our invention, illustrated in Figs- 13 to 20, differs from the modification fully described above in the following principal mechanical details: Instead of having a single blower with branch air ducts leading to the glass printer cylinders, this modication, as shown in Fig. 18, has two separate blowers |66 on either side of the machine, the motors of which are alternated by a make and break switch which consists of an eccentric wheel |61 and two terminals |68 and |69, which alternately contact the wheel |61. The contact wheel |61 is mounted on a shaft |10 which is driven by means of belt i 1| and pulleys |12 vand |13 from the shaft |14 of the main drive motor 61 through reduction gear box |65. The ducts leading from the cooling blowers |66 to the space surrounding the mercury vapor arc tube 22 and the inner glass cylinder 2| are divided into two sections |86 and |81, by a partition |88. The portion of the cooling air that is carried by section |86 is led into the space between the mercury arc tube 22 and the inner cylinder 2| through the openings |89. The duct section |81 carries the remainder of the air into the space between the inner glass cylinder 2| and the outer revolvable cylinder 20.

In this modification, as shown in Figs. 19 and 20, the pinion |95, for adjusting the movable light shield 24, is mounted outside the lamp and housing |96 and above the plane ofthe revolvable cylinder 20. This outside mounting allows for engaging the same pinion with both the adjustment rack 36 and the curved rack mounted on the upper surface of the adjustable shield 24. A rod |91, xed to the pinion |95 by collar |98 and set screw |99, connects the pinion |95 with an identical pinion (not illustrated) mounted on the opposite end of the revolvable glass cylinder 20. Two blowers or evacuators |15 are mounted on either side of the perforated separating cylinder |06, each driven by a separate motor |16. In this modification, the flexible shield |33 is mounted on the front side of the perforated cylinder |06 and the main conveyor belt 85 travels around idler |64 and up past the back of the perforated cylinder |06 around the idlers |16 and |11. Hence, the original instead of the print is sucked against the evacuated perforated cylinder i 06 and is carried to the front of the machine through passage |84, where it is removed from the separating cylinder |06 and placed in trough |18, provided for that purpose. The print which is not affected by the suction of the separating cylinder |06 is carried up to the entrance of lthe developer by the main conveyor belts 85 through the channel |19, formed by guide plates |80 and |81. A series of rocker arms |82 are provided below the separating cylinder |06, to guide the print and original after leaving the auxiliary belts |00 before they reach the separating cylinder |06. These rocker arms |82 may be pivoted clockwise around rod |83, to allow the operator to remove the exposed print and original before the former enters the developer.

A blower 200, operated by motor is mounted at the top of the developer section (Fig. 18) to facilitate the exhaustion of residual ammonia fumes from the space surrounding the developing chamber. A similar installation may also be used on modification I. A starting box 202, operated by handle 203, is provided to throw the motors in.

The drive mechanism for this modification differs from that of modification I in that the drive for the perforated automatic separating cylinder |06 is taken directly from drive shaft |90 by means of the chain drive ISI, which engages sprocket wheel |92, thus driving pinion |93. Gear wheel |94, which is in engagement with pinion |93, is mounted on the shaft 204 of the perforated cylinder |06. The perforated cylinder itself is mounted on either end in housing 205, a ring bearing 2|0 being provided between the two surfaces. The shaft 204, which is connected to the shell of the perforated cylinder by two sets of spokes 2|| at either end of the cylinder, is journaled in a thrust bearing surface 2|2 of housing 205. The openings 2|3, provided in the end housings 205, allow free passage of the air out of the perforated cylinder and into the exhauster blowers |15, which expel it to the surrounding atmosphere. The auxiliary belt system |00 of this modification is driven from the perforated cylinder by means of chain drive 206, which engages a sprocket wheel 201 mounted on the shaft of the auxiliary belt drive roller 208. The mechanism for lowering the main conveyor belts to give the operator access to the printing cylinder is provided with a counter balance 209, in place of the rack and pinion of modification I.

In place of the revolving glass cylinder -20, described in both of the above modifications of our invention, we may use a stationary curved glass surface 232, as illustrated in Figs. '7 and 7a. When using such a stationary curved surface, the stationary envelope surrounding the mercury vapor arc lamp 22 may be either the same cylindrical glass tube 2l as is used with the rotating glass cylinder, or it may be a curved glass envelope 230 which is open on one side. When the cylindrical envelope 2| is used as illustrated in Fig. 7, the cooling media is circulated through the burner assembly in the same or a similar manner as is described above in connection with the revolving glass cylinder 20. In this case, the removable shield 23| serves to close off the open side of the stationary curved glass surface 232 and, thus, maintains a slight pressure in the area around the burner. When the curved glass envelope 230 is used as illustrated in Fig. 7a, the cooling media may be circulated through the burner assembly in the same manner as described for the revolving glass cylinder 2|)A or it may be introduced through slots 233 in the removable shield 23Ia along one side of the burner and removed through similar slots 234 along the opposite side of the burner. In either of these substitute printer assemblies, the work piece is carried across the curved glass surface 232 by means of a series of endless conveyor belts 235 which are driven by drive pulley 236 from the motor and speed regulator 231. 'I'he tension in the conveyor belts may be regulated by adjusting either idler 238 or 233. These latter also serve to insure maximum contact of the conveyor belts 235 with the drive pulley 236. Idler pulleys 240 and 24|, positioned at the point of entry and exit, respectively, lead the conveyor belts around the printing surface of the curved glass surface 232. The cooperating apparatus, such as automatic separating means |06, light shields 23 and 24, auxiliary conveyor belts |00 and |36, developer B, blower and blower ducts, means for removing the lamp assembly, etc., can be adapted to these substitute printer assemblies with slight modifications.

We desire to have it understood that while the modifications of our invention, particularly described above, constitute practical embodiments of our invention, we do not limit ourselves strictly to the exact details, herein illustrated, since manifestly they can be varied somewhat without departing from the spirit and scope of our invention, as defined in the appended claims.

What we claim as new is:

1. In a printing machine for light-sensitive materials, ,the combination with a vapor discharge tube as the source of light and light transmitting means over which the material to be exposed is passed of a light transmitting stationary cover positioned between the said light transmitting means and the light source which will absorb most of the unwanted radiation converting it to heat, and means to alternate a stream of cooling medium between the right and left end of the vapor tube in the area between said stationary cover and the first mentioned lightl transmitting means.

2. In a printing machine for light-sensitive materials, the combination with a hollow rotatable light transmitting cylinder over which the light-sensitive material is passed of a hollow stationary light transmitting cylinder having within it a mercury vapor discharge tube as .the source of light, said stationary light transmitting cylinder and mercury vapor discharge tube being mounted within the rotatable hollow light transmitting cylinder, means to alternate a stream of cooling medium between the right and left end of the vapor tube in the area between the stationary light transmitting cylinder and the hollow rotatable light transmitting cylinder, and means to meter small quantities of the cooling medium into the area between the mercury vapor discharge tube and the stationary cylinder at each alternate passage thereof.

3. In a printing machine for light-sensitive materials, the combination with a hollow light transmitting cylinder over which the light-sensitive material is passed of a luminescent tube within the hollow light transmitting cylinder, a second hollow light transmitting cylinder within the first mentioned hollow cylinder and surrounding the luminescent tube, and means for causing a current of cooling air to flow through the ring-shaped areas between the two hollow cylinders and the inner hollow cylinder and luminescent tube.

4. In a printingV machine for light-sensitive materials, the combination with a rotatable hollow light transmitting cylinder having a hollow stationary light transmitting cylinder and light source mounted therein of a means for alternately blowing cooling air first from one endand then the other through the said cylinders and around the light source comprising blower means and means for periodically reversing the iiow of air. 1

5. In a printing machine for light-sensitive materials, the combination with a rotatable holloW light transmitting cylinder having a stationary hollow light transmitting cylinder and a light source mounted therein of a means for alternately blowing cooling air first from one end and then the other through said cylinders and around the light source comprising la blower, a filter means on the intake thereto, a Y-shaped air duct leading from the blower to the ends of the light transmitting cylinder, a nip valve mounted in the crotch of the Y-shaped air duct to periodically reverse the flow of air, and means to actuate said flip valve. Y

6. In a printing machine for light-sensitive materials, the combination with a rotatable hollow light transmitting cylinder having a stationary hollow light transmitting cylinder and a light source mounted therein of means for' alternately blowing cooling air rst from one end and then the other through said cylinder and around the light source comprising two separate blowers positioned at either end of the hollow cylinders, and means for alternating the operameans within the said housing forming an envelope around the electrode at either end of the lamp also joined in said housing, separable electrical contact means connecting the electrodes of the lamp with an electric circuit, slidable supporting means mounted on carriages connected to the aforesaid housing, and guides therefor to allow removal of the light transmitting cylinder and lamp asaunit.

8. In a printing machine for light-sensitive materials, the combination with a hollow cylindrically shaped light transmitting means over which the light-sensitive material is passed of a luminescent tube within the cylindrically shaped r light transmitting means, a second hollow cylindrically shaped light transmitting means positioned within the 'rst mentioned cylindrically shaped light transmitting means and enclosing the luminescent tube, and means for causing a current of cooling medium to flow through the space between the two light transmitting means.

FREDERICK W. voN MEISTER. FREDERICK W. ANDREW.

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