US2260364A - Ink distribution system - Google Patents

Description

Oct. 28, 1941. c s 2,260,364

INK DISTRIBUTION SYSTEM Filed May 18, 1940 5 Sheets-Sheet l 30 31 29 23 31 INVENTOR BY 49m. 8 ML KM! ATTORNEYS Oct. 28, 1941. L. B. cAsE INK DISTRIBUTION SYSTEM 3 Sheets-Sheet '2 Filed May 18, 1940 mi. vam- INVENTOR ATTORNEYS IIIHHHHMHHU Oct. 28, 1941.

L. B. CASE INK DISTRIBUTION SYSTEM Filed May 18, 1940 3 Sheets-Sheet I 3 5A! ETY VALVE 61' 1 R J STEAM 31 E z? 1 INVENTOR iii-:53; M :::J -J "6.7 24, BY I [c -mu ATTORN EYS Pa tented Oct. 28, 1941 2,260,364 m1; msrnmu'rros srsmu Lynn B.

John

Case, New Brunswick, N. 1., assignor to Waldron Corporation, New Brunswick,

N. 1., a corporation of Jersey Application May 18, 1940, Serial No. 335,924 8 Claims. (01. 101-216) This invention relates to ink distribution systems for printing presses, particularly of the letterpress type. j

Heretofore, commercial letterpress printing has involved the use of printing inks which have the necessary fluidity and working consistency at normal press room temperatures. The ink is wet when printed on the paper and the setting or drying of the print is eflected by oxidation or polymerization of an oily constituent of the ink, or by evaporation of solvents or carriers from the ink or' by absorption of the ink into the paper, or by a. combination of two or more of these. Newspaper printing according to this process is objectionable in that the first impression printing on one side of the paper is inferior to the second impression printing on the other side of the paper; smearing and marring occur frequently during passage of the printing web over angle bars and folders; offsetting of the printing on to the impression roller 01' tympan of the press occurs and the smearing tendency of newspaper printing soils the hands and clothesoi the readers. High speed letterpress printing on comparatively non-absorbent paper stock with quite fluid inks compounded from pigments, binders and volatile solvents requires heating of the web after each impression in order that most of the solvent may be driven off and the print dried sufliciently, to permit immediate second impression or multi-color printing and handling of the printed matter without serious smearing, offsetting and damage to the print.

10% or more and a further-expense is involved in the cost of ink as occasioned by its high solvent and low pigment concentration and its low covering power. 4

Letterpress printing processes of the kind heretofore used are subject to the further disadvantage that the formulae of the inks must be adjusted in accordance with the type and speed of the press, the nature of the medium to be printed on and the ultimate use of the printed matter. This necessarily involves errors in formulating the inks and results in non-uniform printing quality. Furthermore, particularly where the drying of the print is effected by oxidation or evaporation ofvolatile solvents, the

workability of the ink on the press and its drying 1 characteristics are subject to change, thereby causing non-uniformity in the printing process and requiring frequent adjustment of the ink formulae. Non-uniformity of operation also, is caused by changing weather conditions in the pressroom and the variable moisture content of the paper.

Recently there has been developed a letterpress process which involves the use of an ink which is solid at normal pressroom temperatures and 'melts to a fluid consistency suitable for letterpress printing'at elevated temperatures, that is,

In very high speed work, use is often made of inks having solvents which are volatile only at high-temperatures and an intense heating of the printed web'is carried out after each impression to drive of! solvents, the heating being at temperatures which would inevitably burn the paper it not carried out very quickly. Such a process imposes objectionable.complications, difliculties and expense into printing practice. Complicated equipment must be provided for heating the print and the web. The web must be allowed to cool between impressions, necessitating additional lead over the normal of as high as 10 to feet and difliculties are encountered in obtaining I proper registration of contiguous'or superimposed prints due to dimensional changes invthe-web caused bythe heating and cooling operations and dehydration of the paper. The high heating temperatures and solvent fumes create fire and health hazards. Also, an inordinate amount of the paper stock is damaged in practice such that wastage of paper often amounts to as much as temperatures in excess of 1'15 F. In this process,

the printed ink films are set instantaneously when printed without encountering the abovementioned difliculties of known letterpress processes. The ink is heated to an elevated temperature, giving it the desired molten consistency for working on the press and the inking mechanisms and the printing form of the printing-press also are heated to elevated temperatures. The ink in molten condition is applied to the printing surface of the form in thin films which adhere to the printing surfaces at elevated printing temperatures even though the films of ink are quite fluid and the form may be moving at high speed. A sheet or web to be printed is impressed by the inked form, the sheet or web being at ordinary pressroom temperatures or at any other temperatures which are low in relation to the temperature of the molten ink. In this way, the ink is printed from the relief surfaces of the form onto the sheet or web in thin hot films and the extraction of heat from these thin films into the web causes the print to set by freezing instantaneously upon leaving the printing surfaces. Further cooling of the resultant printing either by natural cooling or by artificial cooling in high speed printing work produces a finished print immediately after the printing Operation, which is rigid and resistant to smearing, marring and oil?- setting during succeeding impressions and during the folding, stacking and assembling of the printed matter in further operation of the press.

means for conditioning the ink to deliver it to the plate cylinder at the proper temperature and to so equip the machines involves the provision of heating means in the ink distribution systems.

' Such systems consist essentially of an ink fountain or ink-furnishing element, together with a plurality of hollow metal rollers cooperating with a plurality of rubber or composition rollers to convey the ink from the fountain or furnishing element to the plate cylinder and simultaneously work it into-proper consistency for application to the type on the plate cylinder.

An object of this invention is the provision of heating equipment in the ink distribution system of such character that it is effective to heat the ink in the fountain to proper temperature within a narrow-predetermined range and maintain the ink within said temperature range until the ink is applied by the plate cylinder to'the paper.

According to this invention, means are provided for circulating hot liquid, preferably hot water, through some, or preferably all, of the hollow metal rollers of the ink distributing system and the printing cylinder and in heat exchange relation to the ink fountain or ink furnishing element. 'The printing cylinder and each heated roller is maintained full of hot' liquid so that heat is constantly supplied'to the entire inner peripheral surface, and the hot liquid is caused to flow therethrough. at such rate that a heat balance is maintained. The rate of fiow of the hot liquid is controlled by the size of the outlet orifice which is-so dimensioned that the heat dissipation is balanced by the heat supplied by the liquid. The piping for effecting circulation of :the hot liquid is so arranged that the direction of flow of the hot liquid alternates in the rollers and cylinder in the order of contact by the ink film, thereby effecting substantially uniform distribution of heat supply laterally| across the ink film, resulting in substantially uniform temperature laterally of the film. Means are provided in the circulation system for effecting removal of air or other gas from the circulating liquid to prevent air binding and its attendant consequences. when water is used as the heating liquid, temperatures in excess of 212 F. are obtainable by operation of the system under suitable super-atmospheric pressure. If the system is operated at a pressure higher than pounds above atmospheric pressure, special equipment is required, but for lower pressures standard equipment is used. Instead of using hot water under pressure, where temperatures in excess of 212 F..are desired, use may be made of well-known liquidshaving sufiiciently high boiling points under either atmospheric or superatmospherlc pressure.

Other objects, novel features and advantages .of this invention will become apparent from the following specification and accompanying drawings, wherein:

Fig. Us a diagrammatic sectional view through an ink distributing system embodying the invention;

Fig. 2 is a plan view thereof;

Fig. 3 is a schematic view of said system illustrating one form of liquid heating equipment; I

Figs. 4 and 5 illustrate other forms of heating equipment for the system;

Fig. 6 is a diagrammatic view of a system operating under pressures in excess of 15 pounds above atmospheric, and

Fig. 7 is a diagrammatic view of a modified pressure-type system.

In Fig. 1 is illustrated a typical ink distribution system consisting of a plurality of rotatable hollow metal rollers R and R1, a plurality of rubber or composition rollers R2, an educator roller R: and a fountain roller R4. Means (not shown) are provided for rotating said rollers in timed relation and for effecting axial vibration of certain of said rollers, all as is standard practice in such ink distribution systems. The fountain roller R4 is partially immersed in a pan or fountain F and certain of the rollers R2 contact the print ing surface on the printing cylinder P, between which and the impression cylinder 0 passes a web W of paperor other similarmaterial to be printed. A jacket J partially encloses the pan or 1 fountain F and in the jacket J is arranged a pipe or a pipe coil ill. The Jacket J is filled with suitable liquid for effecting transfer of heat from the coil Ill to the pan F and its contents. Ink is delivered by the eductor R: from the fountain roller R1 to the roller R. From the roller R, ink issupplied by the rollers R2 to the two rollers R1 and through additional rollers R: from the rollers R1 to the printing cylinder P.

A header consisting of a cross-pipe II and two arms l2 and I3 is supplied with hot liquid through a pipe l4. Pipes l5, l6 and I! lead from the arm 12 respectively to one end of the coil l0, one end of the roller R and one end of the printing cylinder P. Pipes l8, l9 and 20 lead from the arm 13 to the opposite ends of the fountain roller R4 and both rollers R1. A discharge header consists of a cross-pipe 2| and two arms 22 and 23 and liquid is discharged from this header through the pipe24. Pipes 2!, 26 and 21 lead respectively from the opposite ends of the coil l0, roller R andv printing cylinder to the branch 22, and pipes 28, 29 and 30 lead respectively from the opposite ends of the fountain roll R4 and both rollers R1 to the arm' 23. The direction of flow in the coil II), the roller R and the cylinder P is opposite tothe direction of flow in the roller R4 and the rollers R1.

' Each of the aforementioned pipes is connectedto the associated roller or cylinder by a standard coupling which permits free rotation relative to the pipe. Such a coupling is standard article of merchandise and is not herein disclosed in detail as the particular construction of such coupling forms nopart of the present invention.

The rate of fiow of hot liquid through the coil I 0, each distribution roller and the printing cylinder is controlled by the outlet orifice therefor.

- 'Such orifice may be of fixed size or may be in the nature of a valve II, whereby the rate offlow may be varied. In each case, the inlet orifice is of larger area than the outlet orifice and has no function in controlling the rate of flow.

the

air pockets or vacuum in the cylinders as liquid is always supplied thereto it is removed therefrom.

Referring now to Fig. 3, the pipe 24 leads to inlet of a tank '1', the outlet of which corn-' municates with the inlet of a pump B and the outlet of said pump communicates with the pipe l4. Operation of'the pump B withdraws liquid from the tank T and supplies such liquid through the pipe l4 to the coil ll, the distribution rollers and the printing cylinder from which the liquid is returned to the tank through the pipe 24. A steam coil arranged in the tank T is supplied with steam througha pipe 33 from any suitable source (not shown) and a pipe 34 returns condensate from the coil to such source. A thermostat 35, arranged in the tank 32, operates a valve 36 by which the supply of steam to the coil 32 is controlled to maintain the liquid at constant temperature.

A pipe 31 leads from the top of the tank T to 'a second'tank T1 at a higher elevation than the tank T, the tank T1 being provided with an air vent 38. A valve-controlled liquid supply pipe 39 communicates with the pipe 31 below the The operating pressure of the system the leyel of the liquid in'the tank Ti, which must be at least high enough to possibility of the occurrence of a at least as fast as.

' some instances not more r and cylinder in the order of contact by the ink.

than 2 F. between the opposite ends thereof. The heat supplied to the rollers and the plate cylinder is so distributed and balanced that there is little or no temperature differential, either laterally or circumferentially, along the surface of any roller or the cylinder or along the ink film. This is accomplished (1) by-maintaining a large mobile or self-equalizing mass of heat in each roller and the cylinder in the form of a body of hot liquid (2) by maintaining at a constant temperature all liquid circulated into the rollers and the cylinder (3) by keeping at a minimum (not more than F. and in than 2 F.) the diflerential between the temperature of the liquid and the desired temperature of the ink (4) by keeping the rate of liquid circulation, through the use of ample pumping capacity, high enough to prevent substantial drop in the liquid temperature during its passage through any roller or the cylinder (5) by selecting an outlet orifice size for the rollers and cylinder in relation to the rate of liquid circulation so that the mass of liquid in each roller and the cylinder is constantly subject to uniform and positive pressure. and (6) by alternating the direction of flow of the circulated liquid through the various rollers In this way, the'ink may be maintained at, subinsure complete filling oi the rollers and cylinder. Figs. 4 and 5' illustrate modified .forms of equipment for heating the liquid in the tank T. In the modification of Fig. 4, steam is introduced into the interior of the tank, through the extension 33a of the pipe ".and the valve It is operated by the thermostat II to regulate the amount of steam supplied to maintain the liquid in the tank at the proper temperature. Air introduced into the tank withthe steam is vented through the pipe In the modification of Fig. 5, a burner 40, preferably an oil burner or gas burner, is arranged in the bottom ofthe tank and is supplied with, fuel through the pipe 4i equipped with a valve 42. The combustion. gases from the burner pass through tubes 43 arranged in .the tank and the flue 44, the combustion gases relation to the liq- The valve 42 is operated by a thermostat 35 to re ate the flow of fuel to the burner to maintain the liquid in the tank T at proper temperature.

In the operation of the in the rollers is dissipated in uid and is carried thereby into the tank T. through the pipe 31 and carried into the system system, any air trapped the circulating liq- The liquid in .the tank 'r is maintained at conxnake-up'liquid introduced the surface of the I stant temperature by operation of the valve 40 by the thermos 't 35. Constant temperature liquid is thus supplied to the coil III, the plate cylinder P and the rollers 01 the distribution system. The rate of flow through each roller and the printing cylinder is controlled by the respective outlet orifices to be such as to supply sufilcient heat thereto to maintain a heat balance therein with a temperature differential of not more than 10 F. and preferably of not more stantially the same desired temperature from its departure from the fountain until after it is applied to the web.

The maximum temperature to which the liquid in the tank can be heated is determined by the boiling point of the liquid'at the operating pressure of the system as above such temperature vaporization of the liquid will occur. Usually fifteen pounds above atmospheric pressure is the maximum allowed plumbing equipment is used, and with water as the heat supplying liquid, the maximum temperature obtainable at such pressure is approximately 250 F. and the operating pressure is obtained by having approximately 34 feet of liquid head in the tank T1. With other liquids having higher boiling points than water, operating temperatures in the range of 250 F. to 50Q F. may be obtained in this system. The liquid may be heated to temperatures of 212 F. by use of superheated steam as the heat source or by use of the heater illustrated in Fig. 5. 3

g. 6 illustrates a system having an operat-' ing pressure in excess of fifteen pounds abov'e' atmospheric. In such a system, the. equipment used is of the so-cailed pressure vessel type which isv sanctioned by law-for highpressures. The pipe 31 is equipped at its upper end with an air vent 45 of-such nature as to permit the escape of air while preventing the escape of liquid. A safety valve 46 is connected to the system, pref 'erably to the pipe 31, and determines the maxithe system. A

stituted for the cylinder and weight piston such,

for example, as a cylinder with an air chamber. Any suitable liquid may be used as the heating medium in the above-described system under the required pressure to maintain the boiling point of such liquid above the desired operatby law where ordinary in excess from its highest point and at its upper 1 steam through the coil 65 steam is so regulated as to a in the tank at a temperature ing temperature. By use of water as the heating liquid, operating temperatures in the range of 250 F. to 500 F. are obtainable'by maintaining the operating pressure in the range of 30 pounds to 679 pounds.

The operation of the system illustrated in Fig. 6 is the same as previously described, except that the operating are higher. The rate of flow through the various units is controlled by the outlet orifices 3| to maintain heat balance with a temperature differential not exceeding F. and the direction of flow alternates in successive units. Also, air is removed from the rollers and air introduced into the system with through the pipe 31, and air vent 45.

With certain types of thermo fluid inks, the printability thereof is substantially the same over a fairly wide temperature range and in connection with the use of such inks close control of the temperature of the rolls is not essential, nor is it essential that the rolls be of substantially uniform temperature throughout theirlength. The apparatus illustrated in Fig. 7 is designed for use with such inks. In this apparatus, a mixture of vapor, air and water is provided'in the 'coil l0, printing cylinder P and the ink feedingrollers R and R1. As close regulation of temperature is not required it is not necessary to provide for high efficiency heat transfer from the heating fluid to the rollers and cylinder. heating fluid be air free as the efiect of the reduced heat transfer efliciency by reason of the presence of air in the fluid is relatively unimportant in the operation of printing with inks of the character above referred to. Also, for similar reasons, it is not essential that the rollers be kept full of substantially constant tem-' perature liquid.

Referring to Fig. 7, the equipment illustrated is of the so-called pressure vessel type which is sanctioned by law for high pressure operation. A tank 60 has a vertical pipe 6i leading end the pipe is connected to the low pressure side of a pressure reduction valve to the 'high pressure side of which is attached a water supply pipe 63. A safety valve 64 is connected to the pipe 6| below the pressure reduction valve 62. In the tank 60 is preferably provided a heating coil 65 through which superheated high pressure steam is circulated by means of the pipes 66 and 61 but any other suitable heating means employed. A pipe I 4' leads from the top of the tank ,60 to the supply header ll described in connection with the previous figures, while a pipe 24' leads from the discharge header'fl, also previously described, .to the inlet port of a pump ,3, the outlet port of which discharges into the tank 60.

In operation, the tank 60 contains water under super-atmospheric pressure. Whenever the pressure in the system drops below that for which the valve 62 is set, additional water is automatically introduced into the system tobring the pressure up to the predetermined value. The safety valve 64 is set to function at some pressure in excess of the predetermined pressure just referred to.-

The water in the tank 60 is heated by passing and the supply of maintain the water predetermined temperature. The

the liquid escapes Therefore, it is not essential that the maybe pressures and temperatures maintain therein a body maintained in the tank 60 is sufto the various units of the ink distribution system. In the ink distribution system, the vapor is condensed and the condensate is withdrawn through the pipe 24' and is returned to the tank 60 by the pump B. in the rollers and cy der depends upon the location of the outlet therefrom. However, in any event, each roller will contain a certain amount of condensate together with air and vapor. Any air escaping from the rollers is returned to the tank 60 along with the condensate and air. as well as vapor, passes from the tank 60 to the distribution system. In a modified form, a vapor trap may be substituted for the pump 3' in which event the condensateis not returned to the tank 60 but is allowed to flow to some source of low pressure, such, for example, as the sewer.

I claim:

1. In letterpress printing with ink solid at normal pressroomtemperature and liquid at elevated temperature wherein the ink isliquefied by heating, supplied from a fountain andtransferred in film form to a hollow printing cylinder by a distribution system including a plurality of hollowrollers, the method which comprises recirculating a definite volume of liquid in heat exchange relation to the ink fountain and through said rollers and cylinder in parallel streams with the direction of liquid flow alternating in the rollers and cylinder in' the order of contact by the ink film, maintaining said liquid at suflicient pressure that its boiling'pqint exceeds the printing temperature of the ink, heating said liquid to a temperature exceeding the printing temperature of the ink and exceeded by the boiling point of the liquid, controlling the outflow of liquid from said rollers and cylinder to maintain therein a body of liquid in contact with entire inner surfaces of said rollers and cylinder, and regulating the flow rate through said rollers and cylinder to maintain heat balance therein with not more than 10 F. diflerential between the inlet and outlet ends thereof.

2. In'letterpress printing with ink solid at normal pressroom temperature and liquid at elevated temperature wherein the ink is liquefied by heatin film tribution system including a plurality of hollow rollers, the method which comprises recirculating a definite volume of liquid in heat exchange relation to the ink fountain and through said rollers and cylinder in parallel streams with the direction of liquid flow alternating in the rollers and cylinder in the order of contact by the ink fllm, heating said liquid to a temperature in the range of F. to 250 F., controlling the outflow of liquid from said rollers and cylinder to of liquid in contact with the entire inner surfaces of said rollers and cylinder, and regulating the flow rate through said rollers and cylinder to maintain heat balance therein with not more than 10 F. diflerential between the inlet and outlet ends thereof.

3. In'letterpress printing with ink solid at normal pressroom temperature and liquid at elevated temperature wherein the ink is liquefied by heating, supplied from a in film form to a hollow printing cylinder by a distribution system including a plurality of hollow rollers, the method which comprises recircu- The amount of condensate fountain and transferred lating a definite volume of liquid in heat exchange relation to the ink fountain and through said rollers and cylinder in parallel streams with the direction of liquid flow alternating in the rollers.

and cylinder in the order of contact by the ink film, maintaining said liquid at suflicient pressure that its boiling point exceeds the printing temperature of the ink, heating said liquid to a temperature in the range of 250 F. to 550 F. prior to supplying the same to said rollers, cylinder and fountain, controlling the outflow of liquid from said rollersand cylinder to maintain therein a body of liquid in contact with the entire ner surfaces of said rollers and cylinder, and regulating the flow rate through saidrollers and cylinder to maintain heat balance therein with not more than F. differential between the in let and outlet ends thereof.

4. In letterpress printing with ink solid at normal pressroom temperature and liquid at elevated temperature wherein the ink is liquefied by heating, supplied from a fountain and transferred in film form to a hollow printing cylinder by a distribution system including a plurality of hollow rollers, the method which comprises recirculating a definite volume of liquid inheat exchange relation to the ink fountain and through said rollers and cylinder in parallel streams with the direction of liquid flow altermating in the rollers and cylinder in the order of contact by the ink film, controlling the outflow of liquid from said rollers and cylinder to maintain therein a body of liquid in contact with the entire inner surfaces of said rollers and cylinder, heating said liquid to supply a body of mobile liquid in heat exchange relation with the walls of said rollers and cylinder, flowing the liquid through said rollers and cylinder at a rate sufficient to prevent substantial temperature drop between the ends thereof; and maintaining the temperature of the liquid supplied to the rollers and cylinder not more than 30 F. above the desired printing temperature.

5. In a printing press comprising a hollow printing cylinder, an ink furnisher, means including hollow metal rollers for conveying anink film from said furnisher to said cylinder and a system for circulating liquid through said. furnisher, rollers and cylinder; .a closed tank containing a body of liquid, means for heating said body of .liquid, a pump and manifolds connectin said tank with said ink furnisher, rollers and cylinder for recirculating liquid from said tank in parallel streams in opposite directions through alternate members of said ink furnisher, rollers and cylinder back to said tank to'efiect uniform lateral distribution. of heat in said film, and means for controlling flow through said rollers and cylinder to maintain constant positive pressure therein exceeding the pressure beyond the outlets therefrom.

6. In a printing press comprising a hollow printing cylinder, an ink furnisher, means including hollow. metal rollers for conveying an ink film from said furnisher to said cylinder and a system for circulating liquid through said furnisher, rollers and cylinder; a closed tank containing a body of liquid, means for heating said body of liquid, a pump and manifolds connecting said tank with said ink furnisher, rollers and cylinder for recirculating liquid from said tank in parallel streams in opposite directions through alternate members of said ink furnisher, rollers and cylinder back to said tank to effect uniform lateral distribution of heat inxsaid film, means taining a body of liquid, means for-heating said body of liquid, a pump and manifolds connecting said tank with said ink furnisher, rollers and cylinder for recirculating liquid from said tank in parallel streams in opposite directions through alternate members of said ink furnisher, rollers and cylinder back to said tank to "effect uniform lateral distribution of heat in said film, means for controlling flow through said rollers and cylinder to maintain constant positive pressure therein exceeding the pressure beyond the outlets therefrom, means for maintaining the liquid .in said tank at constant temperature, and means for maintaining the liquid in said tank under constant super-atmospheric pressure.

8. In a printing press comprising a hollow printing cylinder, an ink furnisher, means including hollow metal rollers for conveying an ink film from said furnisher to said cylinder and a system for circulating liquid through said furnisher, rollers and cylinder; a closed tank containing a body of liquid, means for heating'said body of liquid, a pump and manifolds connecting said tank with said ink furnisher, rollers and cylinder for recirculating liquid from said tank in parallel streams in opposite directions through alternate members of said ink furnisher, rollers and cylinder back to said tank to eifect uniform lateral distribution of heat in said film, means for controlling flow through said rollers and cylinder to maintain constant positive pressuretherein exceeding the pressure beyond the outfrom said tank.

for automatically venting air LYNN B. CASE.

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