US2266849A - Dry spray for preventing offset - Google Patents

Description

Dec. 23, 1941. H. COLE 2,266,849

DRY SPRAY FOR PREVENTING OFFSET Filed Aug. 9, 19 3 Sheets-Sheet 1 INVENTOR Herberi Cot};

ATTORNEY Dec. 23, 1941. H. COLE DRY SPRAY FOR PREVENTING OFFSET Filed Aug. 9, 1958 5 Sheets-Sheet 2 INVENTOR Herberf' Cafe (M4 1 ATTORNEYS H. COLE DRY SPRAY FOR PREVENTING OFFSET Dec. 23, 1941.

mud ATTORNEYS I 'llvllIl/IIIIIIIL lNVENTO R Herberf CoZe 3 Sheets-Sheet 3 llllltlc Filed Aug. 9, 1938 Patented Dec. 23, 1941 UNITED STATES PATENT OFFICE Applica z n zgiz t ih l z8fgzza f 223,831

' 21 Claims.

sorted to in quality printing, and which will be quite as efiective as such expedient for the elimination of smudging and offsetting.

Another object isto provide equipment of the type in which a blast of air, preferably carrying a fine dry powder, is reliably and uniformly blown along the printed sheet so that powder is deposited in amounts adequate for desired prevention of ofi-set'and not so copious as to inter'- fere with subsequent printing operations.

Another object is to provide equipment of the above type which obviates the use of ventilating hoods or the like to protect the workers and which can be reliably controlled to deliver powder in desired amount, substantially only to. the printed sheet rather than beyond the area of the printed sheet.

The invention in general involves the ,use of a tanker reservoir partially filled with a finely divided dry powder, delivering in the case of sheet printers through a tube or hose to outlets directly along the sheet at the jogging box and in the case of a continuous sheet printer alon the delivering web of the printed paper. To propel the powder, a source of compressed air is effectively connected to the tank as long as the printing press is operating. Appropriate outlet control valve means are operated'i'rom the press at each printing cycle to cause the cloud of powder stirred up in the tank by the compressed air introduced therein to be ejected therefrom. Means. is provided, preferably operated at each printing cycle of the press to change the path of entry of the compressed air into and through the powder, so that appropriate stirring up within the tank is at all times assured without tunneling of air through the powder.

There may be used a plurality of separate nozzles, connected to the hose and located at the jogging box to blow upon the sheet as it settles to position, or a single delivering pipe with appropriate spaced outlet openings. In the latter case. breather means are preferably provided at the ends of such pipe to prevent the powder from accumulating therein, and interfering with reliability and uniformity of emission.

In the accompanyingdrawings in which are shown one or more of various possible embodiments of the several features of the invention,

Fig. 1-.is an elevation with parts broken away, of the equipment as installed and shown in more or less diagrammatic form.

Fig. 2 is a more or less diagrammatic view of one embodiment of the equipment, apart from the press with which it is associated,

Fig. 3 is a transverse sectional view on an enlarged scale of the powder tank or reservoir,

Fig. 4 is a fragmentary sectional view taken on line 4-4 of Fig. 3,

Fig. 5 is an end elevation of the air inlet plug, Fig. 6 is a side elevation thereof,

Fig. 7 is a detail sectionalview taken on line 1-1 of Fig. 3, Fig. 8 is a'front elevation with parts shown in section of a distributor spray pipe. arrangement, Fig. 9 is a fragmentary view showing means 'for selectively shutting off spray openings in the embodiment of Fig. 8,

Fig. 10 is a front elevation of an alternative form of nozzle or spray head and associated parts for winding" sheets, and

Fig. 11 is an end elevation thereof.

Referring now to Figs. 1 to 7 of the drawings, the powder tank or reservoir R has a unitary mounting flange I! at its lower half by means of which it is bolted to an appropriate part of the press P. The air inlet control means of tank R in general is shown at I and compressed air is supplied thereto by means of a hose l3 through an appropriate air filter 14, so that only clean air will enter the tank and pass through the powder therein. A pressure regulator valve I5 is interposed between the hose l3 and the filter H by means of which the air pressure may be adjusted as desired to a valve indicated by a reading of the pressure gauge IS. The controlled outlet for the powder cloud formed within the tank by the air blown thereinto is generally shown at O and delivers through one or more shut-off valves I! through conduits l8 to appropriate air and powder spray heads I9 mountedby means of clamps 20 upon the edge of the Jogging box J, or elsewhere as the construction of the press permits or requires.

A master lever 2| pivoted to tank R at 22 is connected by means of a chain 23 or the like to a reciprocating part of the press P. This connection may be made to the lever alternately at 25 or at 28 depending on whether it is more convenient to operate the lever from a part of the press at one side or the other. Lever 2| serves to operate both the inlet control unit. I through which the air is. introduced into the tank and the outlet control unit through which blasts of air with entrained powder are ejected through the spray heads l3.

A shut-off valve 25' of conventional construction mounted by means of flange 28' upon a suitable part of the press is urged closed by a spring, (not shown) to shut of! compressed air through conduit l3 and is held ,open through-- out operation of the press by depression of protruding valve stem 21 by any suitable element of the press that isand em'alns displaced in such position while the press is operating.

Referring now to Fig. 3, the powder tank R in a desirable construction has a rounded bottom 28 with a boss 29 mounting the inlet control instrumentalities I which will now be described. Bushing 38 threaded into the boss 23 mounts a valve seat member 3| having a bevelled seat 32 for the compressed air inlet nozzle 33 which is held in position by means of a screw cap 34. A ball valve 35 seats in the enlarged upper end of the valve seat member 3|, the upper extremity 38 ofwhich is cylindrical and, preferably protrudes into the bottom of the tank.

The powder preferably is packed to a maximum level H less than half the height of the tank. The air duct at the top of the valve seat 3| is of air pipe 45. The scraper will be carried with the step by step rotating valve'seat member 3|,

.plug 38 and air tube 45 to perform such scraping function.

It is understood that the powder is initially merely deposited into the tank R, and is not deliberately compressed therein. After extended use, compacting of the powder may occur. The term packed as applied to the powder is intended to define that powder which rests in the tank as distinguished from the cloud of powder stirred upthereabove.

The outlet 0 comprises an outlet valve casing 58 positioned upon the tank by a stud 5|, protruding into the upper wall thereof. A dome 52 surmounts said valve case, the assembly being firmly secured to the tank by means of screws the master lever 2| by means of a pitman link.

The plug valve 54 has a transverse bore 62 therethrough, alternately brought into and out 3 cf communication in the rocking movement theredesirably formed by a pair of helical grooves 31 about a plug 38 tightly fitting into the cylin-' drical upper end 36 of the valve seat member 3|. If the compressed air were to be blown at all times through the same duct, the likelihood would occur that the compressed air would tunnel its way through the otherwise packed powder,

' of the valve seat and plug 38 is effected by means of a ratchet wheel 40 interposed between the bushing 30 and the cap 34 and affixed to the rotatable valve seat member 3|. Cooperating with said ratchet wheel is a pawl 4| pivoted upon a lever 42 having an eye 43 encircling the valve seat member 3|. Lever 42 is slotted at 43' near its outer end for connection to the lower end of the master lever 2|. Ratchet wheel 40 is thus caused to advance step by step and with it the helical duct 31 in the operation of the printing press. i

Preferably the plug 38 also mounts an air pipe 45 coaxially thereof and of the tank and extending upward through and above the packed powder. 9. small pin-hole nozzle 48. Thus the tank provides a course for blowing a fine jet of air into the tank from above the powder, thereby more adequatelv to agitate the. dust cloud formed by the air which passes by way of plug 38 into and through the packed powder.

In order to avoid possible packing of the pow- Near the upper end thereof, pipe 45 has of, with'respect to corresponding vertical bore 83 through the valve casing.

Preferably the valve has a pair of peripheral grooves at opposite sides of the bore in which fit flexible washers 84 to eflect an air tight connection and prevent leakage of compressed air laterally along the valve 54. Accordingly, a blast of air from the tank with entrained powder will be blown through the open valve when valve 54 opens at each printing cycle.

To assure adequate comminution and distribution of the powder, it is preferred to provide in the lower end of-valve casing 58 a downwardly extending short air tube 85 in axial alignment with tube 45 which has a small crater inlet 86 aligned with nozzle 48. Accordingly the powder will be well distributed in the air entering said pipe from the powder laden air agitated by the let through nozzle 48. For further assurance of uniform distribution of powder, the valve case 58 is provided with a hemispherical cup 68 communicating with outlet port 63 and in line with the conical dome 52. The powder carrying air entering the cup 68 will therefore be further agitated and the powder distributed therein. Similar enlargements occur at the outlets of various restricted fittings in the conduit iii. For instance restricted plug 88 in shut-off valve l1 delivers to enlarged borO 18 therein.

The tank preferably has a removable screw plug 1| through which it may be filled and through which the amount of powder remaining in the tank may be readily ascertained and also has a discharge plug I2 near the bottom thereof In certain applications it is desirable to use; instead of the individual spray heads IQ of Fig. l.

the construction shown in Fig. 8. In this case the air with entrained dry powder is blown deragainst the wall of the reservoir or tank, a

sheet metalscraper plate 41 is preferably provided. the root 48 of which is affixed by means of screws 49 to a collar 50 about the lower end through a pipe 80, perforated at intervals as at 8| and extending over the sheet surface from end to end thereof. Preferably the hose '|8 from the powder tank is connected through a T fitting 82 intermediate the ends of the pipe so that the air and powder will pass out of the various apertures at approximately uniform pressure. In the absence of further provision, excess powder would tend to accumulate in the ends of the tube after operation for a time, and with increase of that accumulation, the apertures 8| near the ends of the pipe would accumulate more powder and deliver more freely than those nearer the middle.

To prevent such accumulation, breathers are provided at each end of the tube, each breather being a depending can 83 of diameter considerably larger than that of the pipe, in which excess'powder that would otherwise collect at the ends, accumulates. When sufllcient powder has accumulated in such breather can, it may be ejected into powder tank R and used again, or be blown out through petcocks 84 at the bottom of the breather. A small vent hole 85 in the cover 88 of the breather can 83 releases enough air to prevent a back pressure of air in said can and so permit drawing the excess powder into the breather without relieying the pressure in pipe 80 to such extent as to impair delivery of the proper amount of powder carrying air through the ports 8|.

The pipe being of the length of the press, it

ments thereof may be set at any angular position so as to straddle a greater or a lesser number of the printed sheets, as desired, to blow therebetween and maintain the same levitated to drop slowly in place within the jogging box so as to cause more effective drying before each printing I sheet settles upon the one below.

Clean air of appropriate temperature, devoid of powder would be blown through the nozzles. In that application it is desirable to have a continuous blast delivered through the hose 18', the force of which might be regulated by adjustment of valve 18 in the embodiment of Figs. 10 and 11,

is desirable in printing on narrow sheets to seal one or more of the ports 8| so that no powder or air is delivered onto the press beyond the edge of the printed sheet. To this end sleeves 81 are provided on the tube 80 which may be slid into position to close those ports that are to be kept out of operation. The sleeves 81 would also be useful for spot-spraying that part only of the printed sheet which would be apt to offset.,

While the dry powder used may be of any of a variety of materials such as potato starch, talcum powder or the like, it is preferred to use.a powdered wax of relatively high melting point and high specific gravity, illustratively carnauba wax. Such wax begins to flow and melt only at temperature well above that reached even in a warm shop, so that the danger of coalescence of the minute wax particles within the tank is obviated. In actual operation such minute well distributed particles of wax as reach the inked area of the sheet are retained thereby. The ink in drying apparently dissolves the minute wax particles which it has intercepted, for the completely dried sheet shows no evidence of the wax except that the inked area has been improved and smoothed by the wax absorbed therein.

The equipment in its various embodiments preferably blows the air with its entrained powder transversely across the sheet and by virtue of its high specific gravity the wax does not float in the air. but what does not settle on the sheet as above described, ultimately settles on the floor.

The air is preferably applied at such pressure that the powder carri d with it is not so dense as to be visible to the n 'ked eye while being blown across the sheet. This degree of adjustment is readily attained by setting of the regulator valve I 5 to an appropriate gauge pressure which will ordinarily be between 6 and 60 pounds, depending upon the area to be sprayed. It is with such setting that the desired off-set prevention is effected without the accumulation of so much powder thereon as to interfere with subsequent printing operations.

An alternative form of nozzle unit for winding or separating sheets is shown in Figs. 10 and 11. The nozzle element thereof is shown of elongated fish tail form as at and is mounted on a swivel 18 upon a bracket 11 to be hung over to a pressure reading registered by pressure gauge I9, which for that purpose is built as a unit with the nozzle unit.

As many changes could be made in the above constructionand method and many apparently widely difierent embodiments of this invention could be made without departing from the scope of the claims, it is intended that allmatter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Having thus described my invention what I claim as new and desire to secure by Letters Patentis:

1. In a printing press, apparatus for preventing smudging or ofisetting of the printed sheet, which comprises a container of dry powder, one or more nozzles adjacent the region where the printed sheet material is collected, a hose connection between the container and the nozzle, means for setting up and maintaining a cloud of powder above the level of powder lodged in the container, said .means including an air duct discharging into said container from below the level the edge or the jogging box, and the nozzle elethrough said nozzle.

of powder therein, a source of compressed air blowing through said duct, and power-driven means for slowly changing the position of said duct in a direction transversely of its length, said apparatus including means synchronized with the printing press for propelling powder from said cloud in the container, under pressure,

2. Apparatus for spraying'printed sheet material prior to superposition thereover of other succeeding printed sheet material, which comprises a source of dry powder, one or more-nozzles adjacent the region of contact between successively printed lengths of sheet material, a hose connection between said source and the nozzles, means for setting up and maintaining a cloud of powder above the level of powder lodged in the container, said means including an air duct discharging into said container from below the level of powder therein, a source of compressed air blowing through said duct, and power-driven means for slowly changing the position of .said duct in a direction transversely ofits length, a

source of compressed air and valve means under .rial prior to superposition thereover of other printed sheet material, which comprises a reservoir having dry finely powdered material therein, one or more nozzles in close contiguity to the printed sheet material to be sprayed, a hose connection from near the top of the reservoir to said nozzle, means to introduce air under comthe reservoir to set tip a cloud of powder in the reservoir above the level or powder lodged therein, said means including an inlet duct to said reservoir, and having an associated drive transmission ior slowly displacing said dust in a direction transversely of its length, and valve means under control of a moving part of the printing press to cause air with entrained powder to blow from the reservoir, upward through the ting air into said reservoir to bring powder into agitation therein, said outlet valve being under control of the printing press to permit air under pressure from within said reservoir to entrain powder therewith through said duct upon the freshly printed sheet.

5. Apparatus for spraying printed sheet material prior to superposition thereover or other printed sheet material, which comprises a reservoir partially filled with a dry powder, a source of compressed air, valve means under control of the press for admission of compressed air into.

the otherwise closed reservoir to permit agitation of some of the powder therein, nozzle means adjacent the printed sheet as it is about to settle in place, a hose from the reservoir to said nozzle means. said reservoir having valve means under control of the printing press governing the emission of compressed air from the reservoir, with entrained powder for election through said nozzles.

6. Apparatus for spraying printed sheet material prior to superposition thereover of other printed sheet material, which comprises a reservoir partially filled with dry powder, a source of compressed air, valve means for admission or air from said source through the powder, to cause agitation thereof in a whirl above the powder, an outlet tube communicating therewith, nozzle means at the delivery end of said tube, contiguous to and directed against the printed sheet as it is about to settle on the previously printed one and outlet valve means on the reservoir under control of the press for delivery of timed blasts of air laden with powder through said tube and nozzle means.

'7. Apparatus for spraying printed sheet material prior to superposition thereover of further printed sheet material, which comprises a reservoir partially filled with a dry fine powder, means under control of the press for admitting compressed air through the powder for agitation thereof in the upper part or the reservoir, means under control of the press; progressively to alter 2,266,849 pression from below the level of the powder in rial prior to superposition thereover of further printed sheet material, comprising a reservoir partially filled with fine dry powder having outlet means in communication with the printed sheet material as it is about to settle in place, a source of compressed air for blowing powder from the reservoir through said outlet means,

means under control or the press for progressively changing the path through which the compressed air enters the reservoir, thereby to prevent tunneling, and scraper means operated from the press to pass progressively along the wall of the reservoir to prevent adhesion of powder thereto. I

9. Apparatus for spraying printed sheet material prior to superposition thereover. of other printed sheet material, comprising a reservoir partially filled with a dry fine powder, means for introducing compressed air through said powder, means for delivering powder charged air from the reservoir, said means comprising a conduit connected to the reservoir, nozzle means at the outlet end or said conduit arranged in contiguity to the printed sheet about to settle in place, valve means under control of the press for timing blasts of compressed air from the reservoir the path through which air is blown into the reservoir, thereby to avoid tunneling in the powder, and an outlet tube supplied from the reservoir and having nozzle means at its delivery end to play upon the printed sheets and outlet valve means at the inlet end of said tube under control of the press, for timed blasts of powder laden air through the nozzle means.

8. Apparatus for spraying printed sheet matethrough the nozzle means, the course of fiow for air from the reservoir to the nozzle including one or more enlarged chambers supplied by small inlets to cause expansion and diflusion oi the powder with the air.

10. The combination recited in claim 9 in which the diffusion chambers are located in various union connections between the reservoir and the outlet nozzles which connect the successive elements making up the conduit.

11. A powder reservoir for spraying printed sheet material which comprises an inlet nozzle at its lower end to be supplied from a source of compressed air, a rotatably mounted plug in the lower end of said reservoir affording a passage displaced from the axis thereof, for admitting air from said source to said reservoir, and means operated from the press for rotating the plug, progressively to change the path or introduction of compressed air to the reservoir, thereby to.

prevent tunneling oi the powder.

12. A powder reservoir for spraying printing sheet material which comprises a boss at its bottom, an inlet nozzle for the compressed air in said boss, a peripherally grooved cylindrical plug fitted into the upper part 01 said boss aifording an entrance for the compressed air into the powder, and a pawl and ratchet connection thereto from the press for step by step rotation of said plug to preclude tunneling 01' air through the powder.

14. A powder reservoir for spraying printed sheet material which comprises a boss at its bottom, an assembly inserted through said boss. said assembly comprising an inlet nozzle for compressed air near the bottom, a cylindrical plug rotatably fitted in said boss and having a helical groove to direct the compressed air obliquely into they powder lodged in the reservoir, a ratchet wheel coaxial with said plug and a coacting pawl operated from the press for progressively revolving said plug to change the point of entry of the compressed air into the powder, thereby to prevent tunneling.

15. A powder reservoir for spraying printed sheet material, said reservoir having a boss at its bottom, a ratchet wheel coaxial with said boss, a pawl operated from the press for progressively rotating said wheel, an inlet nozzle at the lower end of said boss for admission of compressed air, and a furthernozzle supplied from said inlet nozzle and connected for movement by said ratchet wheel progressively to change the point of entry of air to the reservoir to preclude tunneling through the powder and a. scraper also connected for movement by said ratchet wheel, intervening between the reservoir wall and the powder therein.

16; A powder magazine for spraying printed sheet material which comprises a reservoir having powder packed in the lower part thereof, an air inlet nozzle for admission of compressed air through the bottom of the reservoir, an air tube communicating therewith and protruding upward into said reservoir and having a reduced nozzle above the powder packed in the reservoir and a duct apart from said tube delivering from said inlet nozzle into and through the powder.

17. A powder reservoir for spraying printed sheet material, which comprises a reservoir having powder packed in the lower part thereof, an air inlet nozzle for admission of compressed air through the bottom thereof. an air tube aligned therewith and protruding upward into said reservoir and having a reduced nozzle above the powder packed in the reservoir, a duct apart from said inlet nozzle into and through the powder, and power-driven means for slowly displacing said duct in a direction transversely of its length.

18. A powder reservoir for spraying printed sheet material, which comprises a reservoir having powder packed-in the lower part thereof, a nozzle for admission of compressed air through the bottom thereof, an air tube aligned therewith and protruding upward into said reservoir and having a reduced nozzle above the powder packed in the reservoir, a duct apart from said tube delivering from said inlet nozzle into and through the powder, and a second air tube axially aligned with .said air tube and having a reduced inlet "hrough which the powder laden air is expelled.

19. In a powder reservoir for spraying printed sheets, means for introducing compressed air to cause a cloud of powder therein, a cylindrical outlet valve plug having a transverse port, said plug having a lever connection to a moving element of the press for rocking the same alternately into open and closed position and felt rings lodged in corresponding grooves peripherally of said plug at opposite sides of the duct to serve as gaskets.

20. In a dry powder spraying apparatus for use on printing presses, the combination of a powder reservoir having means for mounting the same on the press, a lever, an inlet duct near'the bottom of the reservoir for admission of compressed air into and through the powder packed therein, an outlet valve near the top of the reservoir for directing compressed air therefrom, laden with powder toperform its function, a ratchet wheel coaxial and rigid with said duct and a transmission for advancing said ratchet to progressively change the position of said duct, and for alternately opening and closing said outlet valve, said transmission including a lever linked to the outlet valve and to a pawl for the ratchet, and means to operate said lever from the press.

21. Apparatus for dry powder spray for a printing press comprising a generally cylindrical reservoir rounded at its bottom and having a boss thereon, an assembly mounted in said boss, said assembly comprising a sleeve, an inlet nozzle, a collar clamping the latter against the lower end of. said sleeve, a plug having a helical groove fitted in the upper end of said sleeve, a ratchet wheel coaxial with and aflixed to said sleeve, an air tube coaxial with said nozzle extending upward into said reservoir and having a small outlet nozzle, a sheet metal scraper plate connected to said plug and extending along the wall of the reservoir, a boss at the top of said reservoir having an air outlet pipe protruding downward therefrom into alignment with the air inlet pipe, a cylindrical plug outlet valve through said boss having a. transverse passage therethrough, an enlarged dome cavity in said boss, means for connection with delivery ducts at the wall of said enlarged cavity a lever hinged to the outside of said reservoir, having a pawl connection at HERBERT COLE.

Images