US2201008A - Web-fed printing press - Google Patents

Description

May 14, 1940. c. J. MacARTHUR WEB-FED PRINTING PRESS Original Filed Dec. 17, 1937 4 Sheets-$heet l R O T N E V m y 1940- c. J. MacARTHUR WEB-FED PRINTING PRESS Original Filed Dec, 17, 1937 4 Sheets-Sheet 2 May 14, 1940;

c. J. M ARTHUR WEB FED PRINTING- PRESS Original Filed Dec. 17, 1937 4 Shets-Sheet 3 QNN 3 INVENTOR (Far/(s [100711210 May' 14 1940. c. J. MMRTHUR 2,201,008

WEB-FED PRINTING PRESS Original Filed'Dec. 17, 1937 4 Sheets-sheaf. 4

INVENTOR ATTORNEY Patented May 14, 1940 I WEB-FED ram'rmc mass crimes J. MacArthur, Glen are", N'. J.

Original application December 17, 1937, Serial No. 180,285. Divided and this application July 25, 1939, Serial No. 286,308

7 Claims.

This application is a division of myapplication, Serial Number 180,285, filed December 17, 1937, entitled Web-fed printing presses, which application issued August 1, 1939, as United States Letters Patent No. 2,168,229.

The invention generally relates to new and improved methods in web-fed printing presses and more particularly to multicolor presses wherein fluid inks, lacquers, dyes and coatings 10 are applied to printable web materialsby the intaglio, or so-called gravure, printing principle.

Heretofore, web-fed gravure presses generally have employed substantially the same methods to produce multicolor gravure printing as those employed in the original monocolor gravure presses. The difficulties encountered in striving to maintain uniformity in web tension and the desired degree of accuracy in printing register are traceable to certain deficient methods employed therein and which are the cause of variant printing register, and also excessive wastage of web material.

A brief analysis of these methods and their consequent handicaps may serve to explain the g5 objectives of the present invention. In this connection it will be observed that the principal printing factors are so closely interrelated that to obtain full advantage from improvements in printing cylinders and the web-carrying impression rollers while printing on relatively hard or 45 smooth web materials such .as aluminum foil, Cellophane, board'stocks or hard-finish papers, excessive printing pressures are invariably applied to the web. These excessive and unnecessary pressures are not only detrimental to print- 50 ing performance but causeextreme deformations in the resilient pressure rollers and injurious distortion of web material. Should there be only slight circumferential differences in the multiple printing cylinders, the resulting lags and tugs on 55 web during successive printings, cause continual changes in web tension, variation in printing register, slippings at web splicings and frequent web breaks. I

stoppage of the press to perform any of the several necessary presswork operations, necessi- 5 tates separation of the printing couples, otherwise, should the web remain in pressing contact with the stationary inked cylinders, for more than a brief period, the web would adhere thereto. Also, to prevent the ink in the engravings 10 from drying and solidifying therein, the cylinders are rotated and continually charged with fresh ink. In the former types of presses, the web-carrying pressure rollers are raised from the printing cylinders. sion is relaxed or disturbed, printing register lost, and entire length of web material within the press a total loss as printed materiaL- Again, in resuming printing operation, additional web spoilage invariably occurs in restoring former 20 web tension and printing register. The lengths of web threadings in such presses range from 100 to 250 feet. It is a common'occurrence to wastev from 200 to 500 feet of-web in recovering former printing conditions.

The necessity for these relatively abnormal lengths of web material in gravure presses compared with web-fed multicolor relief printing presses is primarily due to employing web impressing members which bring theweb material into all-over impressional contact with the printing members. In this connection a similar handicap revails in web-fed presses employing the planographic printing principle and which tends to retard the development of multicolor web-fed planographic printing.

Expressed in simple terms, the principal components of multi-color gravure inks comprise:

a solid, synthetic resin (or nitrocellulose) dissolved into a resinous fluid by a volatile liquid solvent. The resin acts as the binding agent for the coloring matter and both of which represent the dried film of printed ink. A freshly printed ink film contains approximately 70% solvent,

and the ink-resin is restored to its former solid, or so-called dry state by the evaporation of its solvent content. However, when the ink is printed on highly absorbent web materials, such as newsprints or machine-finish papers, solvent escape or removal is aided to a great extent by its penetration into the web materials, but in this respect, scant aid is received from hard-finish stocks and none from non-absorbent web material such as aluminum foil, vegetable parchment, etc. During its transitional stages from a fluid Consequently web ten- 15 to a solid, the ink-resin develops ascending degrees of tack until it rehardens. Should undried printed ink 'be brought into impressional contact with un-inked or non-printing areas of the succeeding printing cylinder some of this extremely tacky ink would adhere thereto. To accelerate the natural volatilizing action of the solvents, heating and vapor exhaust appliances are employed between printings. The appliances, according to speed of press, character of web material being printed, volatility of solvent used and solvent retentive properties of the resin, require suificient lengthof web travel to insure that ink is dry or tack-free before it is pressed into contact with the solid surface sections of the succeeding printing cylinder.

Under the foregoing condition including resulting shrinkages of web due to repeated heattreatments between printings the handicaps which hamper press operators in trying to control web tension and printing register on long webs, are obvious.

In effort to reduce the distance of web travel and effect suitable ink drying with lower temperature heat treatments, highly volatile ink solvents are used. Owing to fire hazard, their toxicity and their extremely volatile nature, unused inks formulated with these solvents must be well protected from atmospheric exposure. 'To afford some measure of protection, the printing cylinders including the ink supply are sometimes enclosed in housings insofar as it is possible and practicable to do so. When printing "long run editions the handicaps imposed by these housings in performing presswork operations are less apparent than when printing comparatively "short run editions. In the latter case, cylinder replacements, proofing engraving to determine tonal translations, and printing register, colormatching, washup etc., are frequent. However, despite the inconvenience tolerated, the interior of these housings and their ink contents are ex posed to the atmosphere to gain access to the printing cylinder or remove ink doctor therefrom.

Therefore it is an object of this invention to provide in a web-fed.- gravure printing press of the kind described, printing couple units wherein each unit comprises a printing member, an impression member and inking appliance means whereby the printing couple is separated without disturbing the existing printing position of the web material, or changing the web-impressing position of the impression member, or altering the inking position of the inking appliance, by employing suitable mechanism to remove the printing member from its printing position to an operable, temporary, non-printing position.

It is a further object of this invention to provide means to detect and indicate the exact printing register existing between the web material and printing member when press is brought to rest and printing couple separated, whereby the former existing printing register can be accurately restored after the printing member has been rotated in its non-printing position, thereby preventing wastage of web material when printing operations are resumed.

It is a further object of this invention to provide impression member's having high and low circumferential areas, the high or relief areas having substantially the same circumferences as the printing members and composed of resilient, or semi-resilient or non-resilient materials and which are arranged in relative Positions corresponding with the engraved or inked sections of the printing members, whereby the web material may be brought into impressicnalcontact with only the engraved or inked sections of the printing members, thereby the preceding printed ink is not brought into impressional contact with the un-inked or non-printing areas of the succeeding printing member and which contributes to a great extent in making it practicable to shorten the distance of web travel between successive printings. This web impressional method takes advantage of the natural and rapid tack-acquiring property of a drying gravure ink, and since the wet ink in the inked engravings of the succeeding printing member has a greater amnity for tacky ink than it has for hard-dry ink, transfer of the entire contents of the engravings of the succeeding printing member is thereby effected with less pressure than if the preceding printed ink on the web were hard-dry.

It is a further object of this invention to provide a compact ink applier, cooperating with an ink doctor, and having its ink-discharge andunused-ink returnv channels closed by a gate, preferably with means adapted to open the gate when the printing member is in printing operation, and close the gate when the printing member is in its non-printing position, although the gate may be arranged for manual opening and closing independent of the printing position of the printing member, whereby said ink applier substantially protects its unused fluid ink contents or the like from exposure to the atmosphere while engaged with or disengaged from the printing member or its cooperating ink doctor, including the provision of an auxiliary ink reservoir which feeds a controlled supply of ink or the like to the ink applier, whenever necessary, whereby ink applier and ink supply reservoir cooperatively maintain fluid inks, lacquers or the like in a uniform state of distribution and at desired temperatures, and substantially protect their fluid contents from exposure to the atmosphere, thereby rendering aid in shortening distance of web travel between printings.

It is a further object of this invention to provides. cleansing fluid bath containing high boiling or relatively slowly evaporating solvents such as butyl carbitol, varnol or xylol or a combuination thereof for dissolving nitrocellulose or synthetic resin inks or lacquers whereby the printing member rotating in its temporary non-printing position is automatically de-inked, also cleansed free from foreign accumulations during a few rotations, thereby cylinder rotations may be stopped and unnecessary wear on both cylinders and ink doctor avoided.

It is a further object of this invention to provide preferably a uniformtension on web material while web is in motion or at rest. While any suitable means may be employed as an in-feed, I prefer to use means which may take the form of a single web control element to feed andpull web material into, through and out of printing and ink drying operations in unisonwwith, but substantially independent of, the aid or influence of, the printing couples, including means provided to guide and adjust the web material traversing convex polygonal paths through printing operations.

Other objects of this invention include a vapor exhaust chamber to draw heavier-than-air ink or lacquer solvent vapors downwardly from the freshly printed side on the traveling web so that these vapors may be reclaimed in their most 7 concentrated vaporous tom, and also to arrange an air bailie adjacent to the traveling web and ink doctor to prevent the oncoming air induced by the traveling web from impinging upon the freshly inked engraving of the rotating printing member, and whereby a pocket of almost stagnant air is formed wherein volatile solvents are sluggish and wherein molten ink waxes or resins are unaffected.

The above and various other objects and advantages will be readily understood from the following description taken in connection with the accompanying drawings of preferred embodiments of the invention, in which modifications may be made without departing from the scope of the appended claims.

In the drawings- Fig. 1 is a semi-diagrammatic view in side elevation, partly in section, of a web-fed multicolor press embodying my invention, illustrating the driving mechanism for a series of printing couple units in their printing positions, the single web control e1ement,-and the mechanism for detecting and indicating printing register between web and printing cylinders.

Fig. 2 is a fragmentary view of a printing 0011- ple unitof the type shown in Fig. 1, mechanism for obtaining registration between the web and the printing cylinders in operating printing position, the appliance with gate open,.not visible, and ink doctor, not visible, and the cleansing mechanism for the printing cylinder idle;

vFig. 3 is a detailed cross section of a printing couple unit of the type illustrated in Fig. 2 with printing cylinder in lowered position, the inking mechanism used in conjunction therewith with its gate in closed position, ink doctor disengaged,

and the cleansing mechanism for the said cylinder in operative position;

Fig. 4 is an enlarged fragmentary sectional view of the ink applying mechanism in operative position, -a printing cylinder and an impression member having high and low circumferential areas adapted to impress the web only at engraved portions of the printing cylinder;

Fig. 5 is a similar view to that shown in Fig. 4

except that the inking mechanism is shown with its gate closed and the printing cylinder is shown in associated lowered position;

Fig. 6 is an end view of the doctor blade mechanism showing means for reciprocation of the same and also showing associated gate operating means for operating the gate to open and close ink-discharge and surplus-ink-return channels;

Fig. '7 is a fragmentary sectional detail of a modified ink gate mechanism;

Fig. 8 is a plan view of an individual printing unit of the type shown in Fig. 2;

Fig. 9 is a sectional view taken substantially on the line 9-9 of Fig. 8 of the ink reservoir; and

Fig. 10 is a fragmentary sectional view taken substantially on the line lIl--l0. of the ink reservoir. Y

Referring to Figs. 1 to 3, the web W is supplied from a web supply roll Ill and passes over a driven roller II in frictional contact with a web driving drum H. The web continues around a free roller .86 disposed substantially in a plane normal to a pair of cylinders l8 and comprising a printing couple 2|. The cylinders l6 and 20 arepreferably of the same circumferential size, the cylinder 20 representing the printing member and the cylinder l8 cooperating as the impression mem-' her. The web is adapted to pass between the printing couple 2| and similarly is adapted to pass between the successive printing couples generally designated as 22, 24 and 26. The construction of each of these printing couples, including the first, issubstantially similar, the first having certain registry means to be more fully described later.

Referring to Fig. 2, the printing couple here shown comprisesthe initial unit shown in Fig. 1 and comprises an impression cylinder shaft suitably mounted for rotation in the frame of the machine, not shown. Secured to this shaft 30 is a gear 32 adapted for engagement with a gear 34 fixed to the printing cylinder shaft 36, rotatably mounted in bearing blocks 36 carried by a cantilever bracket means v40 pivotable about a drive shaft 42 rotatably supported in bearings 44 secured to longitudinal rails of the frame, indicated as 46, of the machine.

Also secured to the shaft 36 on one side the printing cylinder and preferably outside the frame 46 is a gear 48 adapted for engagement with a'gear 50 fixed to the drive shaft 42. Re ferring to-Fig. 1 the drive shaft 42 and the gears associated therewith are driven by a worm 52 and worm wheel 54 on a line shaft 56 and the drive shaft 42. The line shaft 56 is in sections for the purpose of simplifying the driving arrangement in the instance shown in Fig. 1. The line shafts 56 are driven by a bevel gear arrangement 58 or the like which comprises an input bevel gear 60 and a takeoff bevel gear 62 on each of 1 the inner ends of the line shafts 66.

With this arrangement it is observed that each of the printing couples rotate in equal phase relation and the printing and impression cylinders of each couple maintain equal surface speeds. Referring to Figs. 2 and 3, and in view of the cantilever supporting arrangement for the printing cylinder 20, the cylinder may be lowered for the purpose of disengaging the printing cylinder from contact with the web. This lowering of the printing cylinder is accomplished by the following means: the bracket 46 is provided with a slide-groove in which a sliding block 63 is adapted to move. Pivotally secured to this block 63 is a gear segment 64, pivoted as at 65, and having an arm 66 articulatively connected to the slidingblock 63. The gear segment 64 is adapted for engagement with a slidable rack 10 suitably supported in the frame, a portion of which is indicated at 12.- In Fig. 2 this rack is shown in its extreme left position and upon movement of the rack in the opposite direction as indicated in Fig. 3, the gear segment 64. as well as the arm 66 and block 63, move leftward to' the position indicated in Fig. 3. The, arcuate movement of the block as aforesaid includes a downward component in that its pivot is confined to an arcuatemovement prescribed around the shaft 65. As will be seen in Figs. 2 and 3 the bracket 40 rests upon the slide-block 63 and upon movement of the block to. the left and downward the bracket 40 is permitted to assume a lowered position as indicated in Fig. 3. thereby disengaging the gears 32 and .34. Referring to Fig. 1

the web-driving drum [4 is rotated by a gear train which includes the gear 32 of the first printing units operate together and that the racks raise and lower the cylinders simultaneously, which can be accomplished by their inter- III in the vicinity of the web, thereby giving conditions which tend to maintain the solvent vapors in concentrated form. A baflle 82a is provided at the inlet side of the printing unit to block air currents which follow the traveling web, thereby providing an air pocket of more or less still air, indicated as 34. This air pocket 84 becomes more or less saturated with the solvent vapors. Such an air pocket tends to prevent the ink in the engravings of the rotating cylinder from'drying therein. The casing 88 is provided witha well 86 containing relatively slow evaporating cleansing fluid 88 such as butyl, carbitol, varnol, xylol or a combination thereof, at a suitable'level Rotatably mounted on the shaft 6,5;is a paddle mechanism 98 partly immersed in abath 10f said cleansingfluid and adapted to splash the cleaning fluid against, the inking surface of the printing cylinder when his rotatting in a non-printing position. Fixed to the shaft 65 and rotatable therewith during rotation of the segment 64 in the lowering of the printing cylinder, is an arm 92 adapted to support a shaft 94 and to move the same arcuately when the cylinder is lowered. This arm 92 is adapted to support a frictional resilient roller 96, which may be covered with glue and glycerin composition, which engages the printing cylinder in its lowered position thereof. 'Adapted to rotate with the friction roller 96 is a sprocket wheel 98 connected as by a chain I 88 to a sprocket wheel I02 rotatable on the shaft 65 but fixed to the paddle mechanism 98.

By the above described arrangement of the cleaning mechanism, the ink on the rotating nonprinting cylinder may be effectively removed by the washing and squeegeed virtually dry by roller 96. A suitable inlet and outlet opening I86 is provided in Well 86 for supplying and removing the cleaning fluid 88, As indicated, the usual contact adjusting means H is provided and retaining means H2 may be applied to the printing cylinder boxes to permit ready removal of the printing cylinder. Transverse register adjustment on web is made by moving the printing couple unit laterally on a slidable support frame, not shown. i

I Referring to Figs. 4 to 8 inclusive the inking gear I38 fixed to the drive shaft 42 aforementioned. If desired, the impeller means I24 can beindependently driven. Also, if desired, impellen means I24 may take the form of a solid tively adjacent the walls I32 and I34. intermediate section may be provided with wall roller mounted upon shaft I26, arranged with an adjustable ink scraping blade so as to pro- .vide a flow of ink outwardly through passage I38, this type of alternate inking apparatus is preferred where certain type of lacquer inks are used which tend to foam if violently agitated. The ink-discharge and ink-retum channels for the impeller mechanism are provided with elongated nozzle walls I32 and I34 which, together with an intermediate section I36, provide outgoing and incoming passages I38 and I40 respec- This portions I42 which may be adapted for receiving a heating or cooling medium in the form of fluid, such as hot oil or chilled water, or' electrical heating means may be inserted in these wall portions I42. It will therefore be seen that the temperature of the ink may be maintained to a suitable degree and in a uniform state of distribution in the ink applier housing. The nozzle walls extend substantially close to the printing cylinder, the'wall I32 atits forward end being provided with a flexible sealing plate I44 adapted to yieldingly contact a doctor blade I46 arranged for suitable operative engagement with the printing cylinder. The lower nozzle wall at its forward end thereof is provided with a flexible inketrap blade I48 adapted to be adjusted adjacent to the printing cylinder surface and the surface tension of the ink or the like prevents leakage thereof while the cylinder is in motion or at rest. The housing I20 is also provided with end walls I50 forming an enclosure at the ends of the ink applier housing, which walls are provided with extensions I52 adapted to embrace the end walls of the printing cylinder. A. felt pad I54 in each of the end walls is adapted to maintain a substantial seal between the cylinder and the extension I52, particularly the space between the blades I44 and I48. The doctor blade is adapted to engage the upper edge of the felt pads to provide a seal at this point and also to provide a wiper means for the doctor blade extensions in its transverse reciprocatory movements. A gate mechanism I56 comprising a member I58 is fixed to a pivotable shaft I60 and provided with a yie'ldable blade I62. In the position of the gate mechanism. shown in Fig. 4 an ink circuit is established up to and including the surface of the printing cylinder between the doctor blade and the ink-trap blade I48. In this position the yieldable member I62 is in engagement with the upper surface of the intermediate section I36, thereby closing off a channel I64 between the forward tip of the intermediate section I36 and the member I53. In the position shown in Fig. the gate mechanism has been rotated counter-clockwise to a position where the yieldable member I62 engages the ink-trap blade I48 to shorten the ink circuit and to by-pass the inking fluid issuing from the impeller around the intermediate section I36 and back, thereby preventing the deposition of ink upon the printing cylinder. The channel I64 is open in this gate position.

Mechanism is preferably provided for openin and closing the gate mechanism I56 in accordance with the raised or lowered position of the printing cylinder, the gate naturally being closed during the lowered position of the cylinder and opened upon the cylinders return to printing position. This mechanism comprises an arm I66 fixed to the shaft 65%see Fig. 6) and pivotally connected as at IIII to {frictional block I12 slidface.

ably engaging the gate operating rod I14. The upper end of the rod I14 is pivotally connected as at I18 to the gate operating arm "8 fixed to the shaft I80. With this arrangement of mechanism the gate is closed upon actuation of the cylinder lowering mechanism and, conversely,-opened when the cylinder is raised to printing position.

A detent mechanism I80 operatively engages the gate arm I18 to urge the gate definitely open or closed.

The doctor blade I48 is adapted to be clamped to a holder bar I82 by suitable means including a clamping blade I84 coopenting withclamp. screws I88. The holder bar I82 is adapted to extend transversely through projections I88 of the inking housing at the ends thereof; the

holder bar passing through suitable openings I80 in these projections. Suitable means I92 are provided and adapted to urge the doctor blade into operative engagementwith the printing sur- Stop means I84 are also provided and adapted to cooperatively engage the holder bar against undue displacement during the lowered or disengaged position of the printing surface from the doctor blade.

The ink appliance housing I20 is provided with suitable ears or extensions I98 adapted to be secured to a cross-bar I98 suitably supported by the frame members 48.

The doctor blade is reciprocated by a barrel cam 200 cooperating with a follower 202 fixed to the holder bar I82. The barrel cam is .rotated by engagement with a gear 204 associated therewith and the impeller gear I28.

Referring to Figs. 9 and 10 the auxiliary ink supply mechanism comprises a reservoir 208 adapted to rotatably support a disc 208in a liquid sealed opening 2I0 in one wall of the reservoir. A shaft 2 I 2 in said bearing and attached to said disc is adapted to project through said supporting wall and is provided with a key 2 adapted for engagement with the driving shaft 42. The driving, engagement is preferably of a separable nature whereby the ink supply reservoir may be quickly disengaged to facilitate ink changes. A supporting projection 2I8 extends from'the frame member 48 and is adapted to swingably support, as at 2I8, the reservoir 208, whereby the driving connection between the shaft 42 andthe' shaft 2I2. may be quickly engaged or disengaged. A locking pin 220 is employed for maintaining the reservoir 208 in engaged or disengaged position. The disc 208'is provided with agitating fins 222 in one side thereof, the other side of the disc presenting a smooth surface adapted to be engaged by a scraper 224 at a relatively high level. The scraper is associated with a receiving cup 228 having an outlet- 228' for gravitationally feeding the ink into the passage I22 of the fountain impeller mechanism. By this means ink in the impeller chamber is maintained substantially at a predetermined level.

Referring to Fig. 1 the printing units are preferably arranged in an arc with the printing cylinders on the convex side and the impression cylinders on the concave side, thus providing substantially polygonal paths for the web. The printing surface of the web is therefore convex and after passing the last printing unit, is projected upwardly around a free roller II to an idler drum I9 and thence over the web control drum I4. A frictional or other suitable roll 2i geared to the web control drum I4 as by means of engagement of the gear-23 with the gear 14, maintains a nonslipping, constant lineal pull at this point which is equal to the lineal feed at the web intake and through the printing couple units. With this means, once the tension on the web through the printing couples is established, equal linear feed and pull under constant tension are obtained, and

in the event the machine is stopped. the tension on the web is maintained. It will be observed that the web by this means is not employed as a power supply or transmittal means for imparting any driving motion to the printing or the impression cylinders and it will also be observed that the rotation of the printing and impression cylinders is not employed for transmitting motion to the .web. Excessive or undue retardation or advance of the web, particularly at the printing lines, is thereby eliminated. In view of the fact that the web feeding and pulling and the printing mechanism are adapted to operate on said web at equal linear speeds and are indirectly connected with the same propulsive power, changes in impression pressure will not vary the tension of the web an registry between successive printing units, thereby and this separation is done after the web and the cylinders are brought to rest. In order that the printing may be rwumed without web wastage usually accompanying a press stop, means are provided to re-engage the printing cylinder with the web in-the precise printing registry prior to the separation. During the separated condition, however. and by means of the arrangement aforementioned, the printing cylinder may be rotated out of registry with the stationary web, the detector and indicating means now to be described affording means to obtain desired re-registry. Referring to Figs. 1, 2 and 8, thedrive shaft 42 of the first unit is provided with a notched disc 232 preferably secured to the gear 80. Engaging the notched disc 232 is an indicator disc 284 adapted to rotate with the notched disc and adapted for manual adjustment with respect to the notched disc when the machine is at rest. This means comprises a bracket 228, suitably secured to the frame 48, provided with an elongated arcuate slot 288 of a size greater than the distance between two adjacent notches. Cooperating with said bracket 288 and adjustable within the range of the slot 238 there is preferably provided a sensing or detector means 240 comprising a barrel 2422 adapted to be secured in fixed position on the bracket 238 by means of a thumb screw 244 or the like. Slidably retained within this barrel 242 is a sensing pin 248 normally pressed outwardly by a spring 248. A button 280 is provided to permit the manual inward movement of the pin 248 against the action of the spring. In operation of this device the machine is brought to rest and in any stationary position one of the notches 282 will come to rest within the range of the limit of movement of the pin mechanism, whereupon the pin barrel is moved so that the pin therein may be depressed into the said notch 282. The particular notch 282 engaged by the pin is designated by moving the indicator with respectto the notched disc so tlfit the pointer thereof is in associated position shown in Fig. 2, thereby designating the particular notch. In this position the pin barrel is locked to the bracket.

It will be observed that in the lowered position of the first printing cylinder the separation between the gears 32 and 34 thereof disconnects the driving train to the web control drum M.

During rotation of the printing cylinders in their lowered position, the particular notch rotates with the pointer of the indicator and when the cleaning operations are completed and the rotation of the cylinder is stopped, the particular notch,whenever it comes to rest,is still designated. Before raising the printing cylinders it is advanced to the position so that the designated notch is engageable by the sensing pin 246. In so doing the printing cylinder is in re-registrable position with the last impression made prior to the separation and upon re-engagement of the web, by raising the printing cylinder into printing contact with the web, the re-registration is effectively established without spoilage of web material when printing operations are resumed.

This re-registry mechanism'is employable preferably on the most convenient unit associated with a series'of printing units cooperating under a common drive.

If desired, local tension adjusting means such as the three rollers 260, 2,62, and 264 are provided, the middle roller 262 being vertically adjustable. The end rollers 260 and 264 are positioned to provide a normal path of the web in its passage through a printing unit. Also provided, if desired, is a solvent reclaiming means comprising an inverted hood 266 disposed substantially close to the printed side of the web andhaving a bailie 268 to prevent an excess of air between the printed side of the web and the hood. Suction means 210 are provided at the opposite end of the hood through which the volatile medium is conducted to suitable reclaiming apparatus, not shown. Where heavierthan-air ink solvent vapors are vaporized, arranging the web to travel face downwardly between printing couples, allows the very advantageous recovery of such heavier-than-air solvents by drawing them downwardly by suction, while they are in concentrated condition. .A similar hood 212 may be provided at the zone surrounding the free roller i1. Disposed over the series of printing units is a large hood 214 extending substantially over the idler drum I9 and the web control drum it. As indicated, this large hood 214 has connected to it a number of suction ducts 216 which lead to the trunk suction duct 218.

Idler drum l9 may have heating or cooling means disposed within the same as is well known in the art, as also may web control drum ll.

As indicated at 280 a plurality. of air injectors may also be provided to assist in the ink drying operation.

As previously noted, reduction in web travel between successive printings while employing allover pressure'rollers in subsequent printing units has definite limitations even under the most favorable circumstances, such as printing on highly absorbent web material and using extremely volatile and low viscosity inks. Therefore referring to Fig. 4, a rigid impression cylinder 28211 is provided with circumferential areas in relief 282 and having areal depressions 283. The relief areas may be appropriate layers of rubber or its synthetic substitutes such as thiokal, etc., or rubber impregnated fabrics, or tough papers or textiles, etc., secured to the surface of the impression cylinder with their suitable adhesives and in relative positions corresponding to the engraved or inked areas 284 of the coacting printing cylinder, whereby the web material 286 may be brought into impressional contacts with only the engraved or inked areas 284 of the printing cylinder, and thereby web impression contacts with the noninked or non-printing areas 285 are avoided, thereby making it practicable to considerably shorten the distance of web travel between successive printings regardless of whether the web material being printed is absorbent or non-absorbent and regardless of whether the ink is wet or dry. This method of impressing the web to printing contacts takes advantage of the natural and rapid tack-acquiring properties of resinous gravure inks and nitro-cellulose printing lacquers and also in two other important respects.

. The wet ink on the engraved cells of the succeeding printing cylinder has a greater aifinity for a printed un-dry, tacky ink than for a printed hard-dry ink. Hence this tacky ink will take or trap" substantially all of the wet ink out of the engravings of the succeeding printing cylinder with less pressurehthan if it were hard-dry resulting in truer translationals of the tonal value of the engravings, because a hard-dry printed ink invariably leaves behind an ink residue of onethird to one-quarter of the wet ink in the cells resulting in the reproduction of faulty or' untrue tonal values. Again this ink residuum dries because it is chiefly solid matter and if not protected from atmospheric exposure will solidify almost immediately in the ink cells. Hence the reason for housing the printing cylinder when employing an all-over impression roller. However with the new and improved ink applier, in cooperation with the new and improved method of applying pressure to web, and in cooperation with a new and improved method of separating the printing couples in cooperation with new and improved methods of web tension control, better quality of multicolor gravure printing can be produced with a substantial saving in web wastage.

It will be obvious to those skilled in the art that various other changes and modifications of the invention may be employed but it is to be understood that the invention is not to be limited to what is described in the specification and shown in the drawings but only as indicated in the appended claims.

Having described my invention, what I claim 1. In a rotary printing press, having a printing cylinder, inking means adapted to supply a circuit of ink in communication with a relatively small and confined peripheral area of said printing cylinder, said means including an ink applying member of small ink capacity having a generally nozzle shaped end portion with an opening, an openable gate in said opening and impeller means to create an ink circuit in said ink applying member, and a detachable ink reservoir means which includes an ink reservoir, agitation and delivering means for ink in said reservoir 'and'connecting means between said reservoir and said ink applying member.

2. A combination as defined in claim 1 wherein the ink is fed from the reservoir to the ink applying means by gravity.

3. A combination as defined in claim 1 wherein the ink is fed from the reservoir to the ink applying means by gravity and which further includes in the ink reservoir means, an auxiliary ink storage cup means adapted to be kept filled aaoaooe continuous web, each couple including an imwith ink andv ink delivery means to keep said cup filled.

4. In a web-fed printing press, a plurality of printing couples each adapted to print upon a continuous web, each couple including an impression cylinder rotatable on an axis in fixed position and a printing cylinder rotatable on a movable axis, a web movable in unison with said impression cylinder, means whereby the printing cylinder is moved into and out of, printing position with said web, and stationary ink-supply means for the printing cylinder and adapted for engagement with the printing cylinder in printing position, whereby the inking means become disengaged from the printing cylinder in nonprinting position.

5. In a web-fed printing press, a plurality of printing couples each adapted to print upon a continuous web, each coupleincluding an impression cylinder rotatable on an axis in fixed position and a printing cylinder rotatable on a movable axis, a web movable in unison with said impression cylinders, means whereby the printing cylinder is moved into and out of printing position with said web, ink-supply means for each of the printing cylinders and adapted for engagement with the printing cylinders in printing position; and gates for closing off the supply of ink to each of the printing cylinders.

6. In a web-fed printing press. a plurality of printing couples each adapted to print upon a pression cylinder rotatable on an axis in fixed position and a printing cylinder rotatable on a movable axis, a web movable in unison with said impression cylinders, means whereby the printing cylinders is moved into and out of printing position with said web, ink-supply means for each of the printing cylinders and adapted for engagement with the printing cylinders in printing position, gates for closing off the supply of ink to the printing cylinders, and means for automatically opening and closing each of said gates in respective printing and non-printing positions of the printing cylinders.

7. In a web-fed printing press, a plurality of printing couples each adapted to print upon a continuous web, each couple including an impression cylinder rotatable on an axis in fixed position and a printing cylinder rotatable on a movable axis, a web movable in unison with said impression cylinders, means whereby the printing cylinders are moved into and out of printing position with said web, cleansing means associated with each of the printing cylinders and normally inoperative in printing positions thereof, and means associated with the printing cylinders adapted to render said cleansing means operative in the non-printing position of the printing cylinders. a

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