US2347511A - Apparatus for preparing plates for etching - Google Patents

Description

April 1944- L SCARZE LLO ETAL 2,347,511

APPARATUS FOR PREPARING PLATES FOR ETCHIHG Filed Dec. 27, 1941 4 Sheets-Sheet 1 A YTORNEY April L. SCARZELLO arm. 2,347,511

. mums FOR PREPARING PLATES FOR momma Filed Dec. 27,1941 4.Sheets-Shet z FIC3.2.

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ATTORNEY INVENTORS April 1944- L scARzELLo El AL 34 5 APPARATUS FOR PREPARING PLATES FOR ETGHING filed Dec. 27, 1941 4 Sheets-Sheet 3 April 25, 1944. SCARZELLO ETAL 2 APPARATUS FOR PREPARING PLATES FOR ETCHING Filed Dec. 27, 1941 4 Sheets-Sheet 4 Patented Apr. 25, 1944 guru UNITED STATES ?ATENT OFFlQE APPARATUS son PREPARING PLATES FOR ETCHING Application December 27, 1941, Serial No. 424,616

2 Claims.

This invention relates generally to etching processes and apparatus and is more especially directed to a method and apparatus for treating plates for the removal therefrom of the superfluous resist, following the inking or design imprinting and resist applying steps in the plate preparation, and preliminary to the heating or so-called baking of the plates, in the process of conditioning them for the etching operation.

At present, it is the general practice, following the imprinting of a design upon a plate and the application of the resist thereto, to form an acid-proof protective coating for the design, to remove the superfluous resist by hand brushing the plate with a camels hair brush. However, this method does not insure entirely satisfactory results, since it is impossible to completely remove such resist as may have been deposited upon the surface of the plate that is to be etched and it frequently happens that in the manipulation of the brush across the portion of the plate carrying the design, that some of the overlying protective coating thereof is loosened and brushed away, with the result that the border or other portions of the design may be improperly etched, while those parts of the plate from which the resist has not been entirely removed will be sufficiently tched. Also, it is not unusual for a plate to have a film of oil thereon, as a result of forming or handling, which further contributes to the impossibility of thoroughly removing the superfluous resist from the plate surface by the use of a hand brush. While, customarily, the plate may be wiped, in an attempt to free it of the oil film, all traces thereof cannot be removed by Wiping and, in consequence, there is a tendency of the resist particles to adhere to the oily surface, which, obviously, increases :he likelihood that the results will be unsatisfaccry.

The primary object of this invention is to provide a method and apparatus for effecting complete removal of the superfluous resist from a plate on which the resist has been deposited by dusting or otherwise to form an acid-proof protective coating for a design imprinted thereon, whereby unsatisfactory results, such as flow from the use of the aforementioned current inefficient methods will be entirely eliminated, our

matter which may have accumulated thereon, in

hand ing, or otherwise, without detrim'entally aifecting any portion of the design-protecting: coating, so that etched product may be producedby the use of our invention which will possess a uniformly high degree of excellence not'heretofore attainable.

More specifically, it is the object of this invention to provide a method and means, whereby the removal of the excess or superfluous resist adhering to a plate, as aforesaid, may be auto-' matically effected to insure not only complete removal of such superfluous resist; but to attain this desirable result in a manner to protect that portion of the resist which is in adherence with the design imprint against possible partial disintegration, as may occur in existing methods. This objective is attained by progressingthe resist treated plate in a controlled path, through a series of zones wherein it is subjected to fluid action, the fluid, in certain of the zones, coacting with means adapted to make physical contact with the plates to supplement the action of the fluid in freeing the plate of all superfluous resist and other non-essential matter which may have been deposited thereon in prior processing;

It is also an object of this invention to provide a method and apparatus having the aforesaid 'nism for delivering it to the baking apparatus,

thereby eliminating handling of the plate between these successive stages of its processing,

and possible surface marring which might result therefrom.

' Other objectives of our invention and advantages flowing from the practicing of the same will become manifest as the description proceeds.

For the purposes or this disclosure, we have" elected to show and describe a preferred form of apparatus. whereby the steps of our method may he efficiently practiced for the attainment of the hereinbefore recited objectives. However, as will be clearly understood, the steps of our method may be performed by the utilization of other forms of apparatus, which may diiier from that herein and described, in various Ways,

within the spirit and scope of the invention, as-

defined by the appended claims.

In the drawings:

Figure l is a top plan View of my preferred form of apparatus. Figure .2 a side elevation looking in the direction of the arrows 22 of Figure 1. Figure 3 is a longitudinal section of the apparatus, taken on the line 3-3 of Figure l.

Figure 4 is a transverse vertical section on the line 44 of Figure 1.

Figure 5 is an elevational view, partly in sec tion, taken on the line 5-5 of Figure 1, of the air-blast unit of my apparatus and the mecha nism for reciprocating it transversely of the conveyor.

Figure 6 is a view in perspective, of the reciprocating brush of the apparatus shown in Figure 1; and

Figure 7 is a perspective of a fragment of the air-blast unit illustrated in Figure 5.

Referring now to the drawings in detail, in which like characters of reference are employed to designate similar parts in the several views, the apparatus embodies an endless conveyor l0, formed of reticulated wire fabric or screening, as at I supported between the link chains l2 and I3, which transverse the sprockets I4 and 5 mounted on the shafts l6 and I! disposed transversely of the apparatus and having bearings in the side forming members l8 and L! of the apparatus. As herein shown, these side members embody supporting feet or legs 29 and 2|, which are formed to receive and support a tank 22 beneath the conveyor, the length and width of which correspond approximately to the overall length and width of the conveyor, for the purposes, which hereinafter, will become apparent.

Supported between the end extensions la and |9a of the aforesaid side members of the apparatus, is a table 23 in the plane of the upper surface of the conveyor, for the reception of the plates indicated at P which are to be placed upon the conveyor for treatment for the removal of the superfluous resist, the plates being entered upon the conveyor, in a hand operation, beneath the transverse end-forming member 24, spanning the conveyor at the plate-entering end thereof. Behind this member 24 are located in appropriately spaced relation, means for spraying a slightly alkaline solution upon the plates carried by the conveyor, as they pass therebeneath. In the present embodiment, these means comprise the pipes or tubes 25 and 26, supported between the side members of the apparatus and spanning the conveyor, which are each provided with a series of nozzles or jets 21 and 28 disposed at an angle to direct the liquid discharged therefrom toward and downwardly upon the advancing plate, the pipes 25 and 26 being respectively connected, as at 29 and 3D, to the take off 2|, from the pump 32, driven by the motor 34, through the shaft 33. The pump draws the liquid which is delivered to the pipes 25 and 26, for discharge from their respective sets of nozzles, from said tank 22, through the line pipe 35 which is disposed parallel to and external of the side l8 of the apparatus and is connected to the end of the tank or reservoir, adjacent the base thereof, through the screened outlet 22a and the branch or lateral piping 35a, parallel to the end of the tank, as shown in Figs. 3 and 4.

As the plate P carried by the conveyor, passes beneath and leaves the zone of the spraying head 26, it is next subjected to the action of a camels hair brush, also connected to the pump take off l 3|, mounted for reciprocatory movement, transversely of the conveyor. This brush includes a head or body-portion 36, having internal spray passages or conduits, with which the tube 3'! carried thereby communicates, the latter being connectable by the flexible tubing 38 to the pump take off 3|, as stated, by the T 39. A rod 40, fixed latter from the complemental bearing end Me of the arm 4|, dependent from the slide 42, for relative adjustment, through the medium of the set screw 42b. The slide 42 is reciprocable on the squared shaft 43, mounted in the bearing portions 44 and 45 of the brackets 46 and 41, bolted to the side members of the apparatus, as at 48 and 49. As will be noted, the longitudinal axis of the brush head, as clearly shown in Fig. l, is disposed at an angle of approximately 45 to the median line of the conveyor, so that as the brush is reciprocated transversely of the conveyor, as hereinafter described, the brush will move across th plate P at an angle to its direction of travel, to cause the vertically dependent hair of the brush, indicated at 36a, to contact with and pass over the plate in a wiping sweep, the liquid emitted from the spray passages of the brush head into the hair flowing therethrough to discharge upon the plate, also serving to keep the brush clean and continuously maintain it in a substantially vertical position, relatively to the plate surface over which it is passing, in brushing contact, as aforesaid.

Appropriately spaced behind the reciprocating brush 35 is a second camels hair brush of a length corresponding to the width of the conveyor, the body-portion 50 thereof, from which the hair 50a is vertically dependent, being mounted within an embracing spray head 5|, fixedly supported between the side members l8 and IQ of the apparatus, transversely of the conveyor, and connected to the pump riser or take off 3|, as by the pipe 52. This spray head 5|, as shown (see Fig. 3) is formed to direct the liquid discharge downwardly toward and upon the opposite faces of the brush, as at 53 and 54, and. similarly to the liquid discharged from the brush 3B, and at the same time cleanses the brush and maintains the hair substantially vertical, as the plate passes beneath the brush and is subjected to the action of the hair in contact therewith and the liquid discharged thereon.

As pointed out, the spray heads 25 and 26,

the reciprocating brush 36 and the spray head 5| embracing the stationary brush 50, 50a, are each connected to the pump 32 which delivers thereto the alkaline solution drawn from the reservoir or tank 22, for emission from the respective units in the performance of the several steps of my process of treating the plate, as hereinafter ex- 7 plained, the solution draining through the conto the brush head or body-portion supports the 76 veyor into the tank, so that, in effect, continuous circulation of the solution is maintained during the operation of the apparatus, the tank serving asthe source of supply.

Positioned behind the stationary brush 50, 50a, is another spray head 55, which similarly to the spray heads 25 and. 26, is disposed transversely of the apparatus and fixed to the side members l8 and I9, which also is provided with nozzles or jets, indicated at 56, also set at an angle to direct a discharge of clear water toward and uponthe advancing plate, as it moves from the zone of the aforesaid stationary brush. This spray head 55 is connected to a source of clear water supply, as by the pipe or conduit 51. The water issuing from the nozzles or jets 56, flushes the plate as itv passes through the effective zone of the nozzle discharge, to remove therefrom any brush hairs or other matter there may have adhered thereto, during the passage of the plate beneath the contacting brushes, and any traces of the alkaline solution that may remain on the plate, the water draining through the conveyor into the tank 22, to mix with the solution therein. To prevent undue dilution of the tank solution, by

the water discharged from the spray head jets cludes a head 64 carrying two laterally spaced.

parallel nozzle sections 60 and BI with their axes disposed transversely of the conveyor, each of which is provided with a series of jets or outlets, indicated at E2 and 63, so located that the air,

streams impinge upon the advancing plate at an angle of approximately 45 to the surface thereof, the head including an upright piece of tubing, fixed thereto, as at 65, which is connectable by the flexible tubing 66 to the conduit 61. leading to an air compressor or other source of air supply. The tubing 66 is adapted to be entered in the bearing end 6841 of the rod 68, the latter being mounted in the bearing portion 89 of the arm 19 dependent from the slide 1| reciprocable upon the shaft 72 fixed between suitable brackets 12a and 12b bolted to the apparatus, similarly to the brackets 48 and 47. To admit of the adjustment of the air device relative to the surface upon which the air streams emitted thereby are to be effective, the tubing 56 is axially and rotatably adjustable within the complemental bearing 63a, a set screw 73 being provided to lock the tubing in the desired position of adjustment therein. Similarly, the rod 68 is adjustable within the bearing with which it is engaged, for adjustment longitudinally of the conveyor, to permit of proper spacing of the air device between the adjacent spray head and the take off end of the conveyor for efficient performance, the rod being locked in adjusted position with the bearing sleeve by the set screw 13.

A gear box of housing 16 is supported by a bracket 1'5 fixed to the side member IQ of the apparatus, which encloses a suitable reduction gear train (not shown) adapted to be driven from the electric motor '1? mounted on the bracket 13, which is bolted to the apparatus. The motor torque is transmitted to the drive shaft of the gear assembly, through the belt 3!, travelling upon the pulley l9 keyed to such shaft 85.. A shaft 82, which is journaled in bearings 83 and 8A, asg sociated with the aforesaid brackets 45 and 13, embodies a worm gear (not shown) adapted to mesh with the driving gear of said gear train, suitable bearings for said shaft 82, in juxtaposition to said worm, being provided in the gear case 15, through which the shaft extends, shown in Fig. 1.

Fixed to the end of the shaft 82, adjacent the bearing 84, is a crank 86 connected by a link 8'! to the slide 42, from which the brush 35 is de'-. pendently supported, as explained, while keyed to the other end of said shaft is a similar crank 88, which, likewise, is connected by a link 85 to the slide H which carries the air discharge device. As will be manifest, the rotation of the shaft 82 in a clockwise direction, (as viewed in Fig. 4) as it is driven from the aforesaid gear as; sembly, will produce reciprocatory movement of the slides 42 and H on their respective guide shafts 43 and 2, with the result that the brush ance of that final step of the process.

36 and the air discharge device carried by said slides 42 and H will travel to and fro across the conveyor, in relatively alternate directions, because of the diametrically opposite disposition of the cranks 86 and 88 on the shaft 82, which, of course, also serves to balance the shaft action, with the concomitant advantages,

In practicing the steps of our method of removing superfluous resist from a plate, in the processing of such plate for etching, by automatically functioning means, as embodied in the form of apparatus just described, the plate P is transferred from the table 23 to the conveyor by hand, as explained, the subsequent steps being automatically performed as the plate progresses through the apparatus, so that all further handling of the plate to and through the baking stage of the processing is entirely eliminated, as will become apparent. Now,'as the conveyor ill traverses the sprockets l4 and IS, the plate is advanced through the apparatus in a continuing operation for treatment in a series of spaced zones, the first of which is that in which the spray head 25 is efiective, the surface of the plate being exposed to the action of the alkaline solution discharged from the nozzles thereof, beneath which it passes to receive the angularly impinging liquid jets discharged from the nozzles 28 of the spray head 26. The pressure of the liquid issuing from the nozzles of these two spray heads is sufficient to force or drive off the resist from the non-imprinted portion of the plate, but not strong enough to separate or produce disintegration of the resist that is in ad herence with the inked design, with a result that the greater part of the superfluous resist, especially that which may be readily flushed off, is removed in the first two zones through which the plate travels.

-As the plate moves beneath the reciprocating brush 35, the end of the brush makes physical contact therewith and passes over the surface thereof in a wiping action, as heretofore explained, the action of the brush, combined with that of the liquid discharged through the brush serving to loosen and remove such particles of the resist as might adhere to the plate surface because of a slight oil film that usually remains on the plate from previous treatment. The alkalinity of the solution in cooperation with the wiping action of the brush contributes to clearingthe oil film from the plate surface which is essential in attaining action of the etching solution, when the plate is ready for the perform- In this connection it may be pointed out the effectiveness of brush is enhanced, since both the plate and brush are in motion, the latter moving across in a path at an angle of approximately 45 to the path of movement of the plate. While the brush action is sufiicient to loosen resist still adhering to the plate surface, following the flushing to which the plate is subjected by the spray heads 25 and 28, the imprint upon the plate has sufficient adhesive qualities to maintain the overlying protective coating completely intact, against such pressure as may be applied thereto by the brush 36 in passing thereover.

As the plate progresses from the zone of the brush 35, it is subjected to the action of the fixed brush 50, a, the hair tufts of which act vertically of the plate moving beneath it, the eiiect here, of course, differing from that of the wiping action of the brush 35, since the plate only moves with relation to the brush, the effective action being solely dependent upon theliquid flow through the brush and the maintenance of the brush hair in a substantially constant vertical position. On passing from the area of the stationary brush 50, 59a, the plate enters the zone of the spray head 55, the fresh wateremitted from the nozzles 56, flushing the plate surface, without of course, affecting in any way the bond of the resist with the imprinted design, and floating therefrom any traces of alkaline solution and such particles of resist that may still remain on the plate surface, together with any other foreign matter that may have accidentally been deposited on the plate, as hairs that may have become loosened from one or the other of the brushes,

The thoroughly washed plate now moves into the air zone of the apparatus, being subjected to the effect of the impinging air streams directed tangentially to the plate surface from the aforementioned air device, the air spreading over the surface to displace the major portion, if not all of themoisture which may remain on the plate surface, so as to condition it for transfer to the baking stage of the plate processing in a fairly dry state,

As the plate leaves the zone of the air device, it is advanced beyond the rear end of the conveyor to be engaged by the take-off roll 90, the flexible fins of which frictionally engage the underside of the plate and urge it toward the train of rollers 91 which move it to a position to be picked up by the conveyor 92, whereby it is delivered to the baking oven, (not shown), the

movement of the two conveyors It] and 92 being synchronized, the conveyor la, in the present showing being driven from the conveyor 92, through the medium of a chain lta in meshing engagement with the sprockets 93 and 94,

sprocket 93 being mounted on the shaft 95 of the conveyor 92, while the sprocket 94 is keyed to the shaft it of the apparatus conveyor {0. The take off roller 90 and the rollers 9| associated therewith are driven from the other end of the shaft l6 of the apparatus, through the medium of the link belts 96 and 91 in engagement with suitable sprockets on said rollers. As will be obvious, the conveyor It] may be independently driven, or may drive the conveyor 92, and the drive for the take-- off roll and the transfer rollers may differ from that herein shown.

As the plate passes through the apparatus on. the conveyor ID, the alkaline solution discharged from the units connected to the pump line 3|,- and the water-issuinglfromthe spray head 55 percolate through the 'meshesof the conveyor,

carrying into the tank 22 the resist and other matter that has been removed from the plate in its transit through the apparatus.

floats to the top of the tank solution and ultimately is discharged from the outlet 22b located at the forward end of the tank, beneath the table 23 of the apparatus. As heretofore explained, the requisite degree of alkalinity of the tank solution is maintained, by introducing an ammonia solution thereto, from time to time, to offset the diluting effect of the water draining into the tank from the spray head 55.

From the foregoing, it will be manifest that the steps of my method are automatically performed in a sequence, involving in each instance the exposure of the plate surface to fluid action, which in certain of the steps is supplemented by mechanical means effective upon the plate The mat-' ter, some of which may be in a colloidal state,

surface, under the influence of the coacting fluid to remove therefrom all matter that is extraneous to the protection of the imprinted design, so that the surface of the plate that is to be etched is devoid of any oily film, scale or other deposit which will tend to arrest the action of the etchingacid. Further, by utilizing our invention, the integrity of the imprinted design is insured against the action of the etching acid, since the resist coating thereof is in no wise affected, as the plate progresses through an apparatus for treatment, according to our method, even in the border area of the design, where the adherence between the ink and the resist applied to the design may not be so great as elsewhere.

While we have described our invention, as it may be practiced in conjunction with apparatus of the type herein shown, it will be understood that the steps thereof may be carried out by other means and the sequence of the steps may vary, the apparatus shown and described obviously, being subject to changes in structure and mode of assembly and cooperation of the components thereof, to meet specific requirements of production and use, all of which fall within-the spirit and scope of our invention.

We claim:

1. An apparatus for automatically removing superfluous resist from the surface of a plate, as a step in a process for preparing such plate for etching, including a conveyor adapted to receive the plate and transport it in a continuing movement through said apparatus, a pair of spray heads supported above said conveyor, in spaced relationship, having nozzles adapted to direct a surface in the path of wiping movement of .the, brush thereover, in theremoval of the super fluous'resist, a second brush fixedly supported from said apparatus disposed transverselyof said conveyor, in rearwardly spaced relation to said reciprocating. brush device, means for saturating said fixed brush with liquid to co-act with said fixed brush as the plate passes beneath said latter brush in contact therewith, means for connecting. said spray heads, said reciprocating brush device and. said fixed brush to a source of liquid.

supply,a .spray head'in rearwardly spaced rela,-.

tion to said fixed brush, an air discharge device supported rearwardly of said liquid-emitting spray head adapted to discharge air upon the surface of the cleansed plate for drying, andmeans for reciprocating said airdischarge device transversely of said conveyor for vaporizing the;

moisture from said plate. Y

2. An apparatus for automatically removing superfluou resist from the surface of a plate,-

as a step in a process for preparing such plate-for etching, including a conveyor adapted to receive the plate and transport it through said ,appa -cratus in a continuing movement, spray heads fordirecting an alkaline solution upon said plate.

during the progression of the plate on said conveyor, a liquid saturated brush supported above said conveyor in rearwardly spaced relation-to said spray heads, means for reciprocating said brush transversely of said conveyor to wipingly traverse said plate, whereby the saturating liquid shed by said brush in its wiping contact with the plate will flush the surface of said plate simultaneously with the movement of the brush thereover, a second brush fixedly supported from said apparatus and extending transversely across said conveyor rearwardly of said first brush adapted to flexibly contact with the plate passing thereunder, means for subjecting the brushed plate to the cleansing action of water directed thereupon while said plate progresses on the conveyor, and a reciprocable air discharge device for evaporating the moisture from said plate.

LEO SCARZELLO. JOSEPH NOWATIUS. MARTIN BULIN.

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