US2102641A - Method of and apparatus for planographic printing - Google Patents

Description

Dec. 21, 1937. H. c. OSBORN v I 2,102,641

METHOD OF AND APPARATUS FOR PLANOGRAiHIC PRINTING 1 Filed Nov. 22, 1934 2 Sheets-Sheet l MGWW Dec. 21, 1937. H. c. OSBORN 2,102,641

METHOD OF AND APPARATUS FOR PLANOGRAPHIC PRINTING Filed NOV. 22, 1934 2 Sheets-Sheet2 //4 48 49 M #2 2 #3 73 4 g a; A" o 4. Z; 4/ W. I! 7 Z 59 5-3 7/ IL! 60 L I ll I l I If 6 Patented Dec. 21, 1937 UNITED STATES METHOD OF AND APPARATUS FOR PLANO- GRAPHIC PRINTING Henry C; Osborn, Cleveland, Ohio, asslgnor, by

mesne assignments, to Addressograph-Multigraph Corporation, Cleveland, Ohio, at corporation of Delaware Application November 22, 1934, Serial No. 754,247

10 Claims. (Cl. 101-148,)255;

This invention relates to a method and apparatus for planographic printing, and is especially concerned with a method and apparatus for applying an ink repellent to a printing plate used in aplanographic printing system.

In general, planographic printing systems employ a metallic printing plate, usually zinc or aluminum. Such plates are treated, by methods well known in the planographic art, to render their non-image areas receptive to an ink repellent. The ink repellentis generally in the form of a liquid and during the printing operation is continually applied to the printing plate so that the ink will not adhere to the non-image areas thereof. Thus, the non-image bearingportions on the printing plate during the printing operation carries a thin film of moisture or repellent. An inking roller is brought into contact with the printing plate and the image areas thereof are supplied with ink, the repellent on the non-image bearing areas preventing the ink from adhering to such areas. Generally ink on the image is then removed from the printing plate by a suitable ofiset roll and transferred to the article to be printed. The plate is again furnished with a fresh application of ink repellent and ink and the operation is repeated continuously. The general object of this invention is to provide a method and apparatus for applying an ink repellent solution to the printing plate in such a manner as to enhance the reproduction of the design or image.

In the past it has been the practice to apply the ink repellent to the printing platie by a dampening roller, which generally comprised a brass core covered with successive layers of flannel, and an outside layer or covering of molleton or other cotton fabric. Occasionally, cushioning layers of other materials have been used instead of the flannel, such layers being surrounded by an outer cover of molleton, as in the case of the flannel layers. A distributor roller was used to supply the repellent to the dampening roller. The distributor roller was usually a smooth brass roll, which was generally assembled in the same frame as the printing plate or in a directly associated frame.

Great care has been exercised in inking the plate to apply the ink evenly and in proper amounts to the image, so as to enable a faithful and accurate reproduction of the image without blurring or raggedness of the impression. For this purpose complicated inking mechanisms have been devised in which much attention has been paid to the smoothing and distributing of the to the action of the repellent applicator system on the plate other than to attempt to secure the proper amount of repellent to prevent the ink from adhering to the non-image bearing areas of the printing plate. I have found that the fabric- 10 wrapped repellent applicator roller affects the distribution of the ink over the image bearing areas in several ways. First the fabric surface of the roller is uneven, and the lint or short fibers in the fabric form ridges on the surface of the roller which increase with-the use of the roller. It is well known, that after the inked image has been transferred from the plate to the offset roll or article to be printed, a considerable quantity of ink still remains on the image-indeed a sufficient amount to make several impressions. Test impressions made in the absence of the repellent roll indicate that this surplus ink is evenly distributed over the image.

a In the normal operation of a planographic printing press, the plate with ink retained thereon after one impression or transfer has been made, is subjected to the action of the repellent applicator roll. .I have found that the roughened or linty surface of the repellent applicator roll disturbs the evenness of the surplus ink on the plate to such an extent that even though utmost care is used in subsequently applying ink to the plate, the result is that the coating ink on the image is somewhat uneven and a poor impression is liable to result. The lint ridges on the applicatorroll seem at times to cause the ink remaining on the plate to form in ridges thereon thereby causing raggedness of the impression. An object of the present invention is to provide a repellent applicator to overcome this disadvantage and thereby facilitate the making of more accurate reproductions, and I prefer to accomplish this object by the provision of a repellent applicator which will present at all times a smooth surface to the printing plate.

A smooth surfaced rubber applicator roll will not become saturated with ink as does a fabriccovered roll. However, the roll does pick up some vof the ink remaining on the plate after an impression has been made, but the use of a rubber roll turns this from a disadvantage to an advantage, because such roll picks up the ink from blemished portions of the non-image areas of the plate and, due to the difference in peripheral lengths of the printing drum and the rubber roll, will transfer such ink to available portions of the image on the printing plate.

Another disadvantage of the fabric covered repellent applicators is the fact that they are difficult to adjust, to control, with any degree of accuracy, the amount of liquid repellent applied to the printing plate. I find that the fabric acts as a reservoir which at the outset must be filled with repellent before "the actual printing operations can take place. I also find that because the adjustment of the supp y of repellent is difficult, generally too much is supplied. This is especially true when the press is operated by a nonprofessional, as is the case with ofilce equipment.

Some of the excess supply of repellent-seems to be left in minute globules on the ink remaining on the image of the printing plate after an impression has been made. When the inking rollers contact with these globules of repellent an emulsion is formed, thereby changing the nature of the ink itself and resulting in an impression which seems to smear readily.

Another object of the present invention is to provide a method and apparatus easily adjustable to apply the proper amount of repellent to the printing plate and eliminate the adherence of surplus repellent on the image bearing areas of the printing plate. I prefer to accomplish this by applying the repellent to the printing plate with a comprmible, non-liquid-absorptlve roll. I find that such a roll has an added feature, namely, if the condition of the plate and speed of the press is such that it is desirable to provide contact with the plate of an excess amount of repellent, such excess may be fed to the applicator roll and the pressure of the roll controlled so that it will act on the plate as a squeegee and remove anywexcess repellent, such excess forming a wave extending along and in front of the line of contact between the roll and the plate, and dropping into the gap inthe drum which carries the printing plate. The gap in the drum may be provided with a suitable absorbant material to take up the excess.

To prevent oxidation of the printing plate, which would negative the treatment given to the non-image portions of the plate to make such areas repellent, substances including certain salts are added to the solution and render it slightly acid. Unfortunately, due to the acidity of the solution, an electrolytic action is set up which is detrimental to the plate and especially to the image-bearing areas.

The electrolytic action tends tocorrode the printing plate and changes the pH" of the solution to such an extent as to render the solution less capable of acting as an ink repellent. This electrolytic action is caused by the formation of an electrolytic cell, in which the repellent fluid acts as an electrolyte, the machine frame as an external circuit, the printing plate as an anode. and the metallic portion of the liquid feeding rollers as a cathode. This condition is especially noticeable where the printing plate is made of zinc or aluminum, and a brass or other metallic member is used in the repellent applicator system.

Several methods have been advanced to eliminate this electrolytic action. Suchaaforinstance, the making of some or all of the rollers in the ink repellent applicator system of the same material as the plate, or of a non-metallic composition, or of a material having the same electric potential as the printing plate. Such methods of elimination have disadvantages which are diflicult to overcome. To make the applicator roller, which contacts with the plate, of metal would not permit the use of such roller as a squeegee roller and would make adjustment of the amount of repellent to be applied diflicult, with the attendant disadvantages heretofore mentioned.

If an attempt is made to eliminate the electrolytic action by the use of non-metallic members throughout the applicator system, it is often difilcult to keepsuch members from becoming clogged or covered with printing ink. Many other disadvantages have been encountered in such system, nor is the situatlonimproved by insulating the bearings of the rollers to interrupt the outside circuit (as has been proposed) as this increases the undesirable static electricity in the press.

To overcome the formation of an electrolytic cell, I prefer to make the repellent applicator roll, which contacts with the plate, of a material which will not act as a cathode or as a conductor of electric energy, preferably of rubber or a composition having similar characteristics. I thereby eliminate any chance of electrolytic action being formed between such applicator roller and the printing plate. However, to prevent such roller from becoming covered with ink, requiring frequent removal for cleaning purposes, I may provide a metallic distributor roll, which will be arranged to contact with the non-metallic roll.

and act not only to distribute the repellent to such roll, but to maintain the applicator roll standing such metallic roll might constitute a cathode and the printing plates an anode, I am still able to prevent for all practical purposes electrolytic action from taking place. The repellent appllcator roll having a surface which will not absorb liquid repellent materially decreases the action of the electrolytic cell. The return stretch of the applicator roll between the printing plate and the, distributor roll, which stretch or surface has given up the greater part of its repellent to the printing plate, is comparatively dry due to the squeegee action of the roll, and hence any electrolytical energy must pass through the thin film of liquid repellent on the opposite surface of the applicator roll, and as such portion of the roll iscovered with only a minimum amount of repellent the resistance to the passage of electrical energy is great. I further increase such resistance by lengthening the peripheral distanceon such roll by employing a roll of comparatively large diameter. Thus-by thinning the film and lengthening it; I increase the resistance until it is so great that for all practical purposes it will prevent any" electrolytic action from taking place, even though the elements of an electrolytic cellbe present, This, therefore, is another feature of the invention.

Other features of my invention will be hereinafter more fully set forth in connection with the following description, which refers to a preferred form of apparatus. shown in the accompanying drawings, and which may be used to carry out my improved method. 'lhe essential features of the invention will be set forth in the claims.

Referring now to the drawings, Fig. l is a centrally located vertical section through the planographic printing press having my improved repellent applicator incorporated therein; Fig. 2 is a fragmentary sectional view, of the press shown in Fig. 1, illustrating my improved re pellent applicator on an enlarged scale; Fig. 3 is a fragmentary sectional view of the repellent applicator indicated by the line 2-3 on Figs. 1 and 2; Fig. 4 is a side elevation of my repellent applicator looking from the right-hand side of Fig. -3; Fig. 5 is a fragmentary sectional view, as indicated by the line [-5 on Fig. 4.

Referring again to the drawings, and especially" to Fig. 1, I illustrate one form of planographic printing machine, in which my improved repellent applicator is arranged to carry out my- .method. Such printing} machine comprises in general a pair of frame plates A spaced apart by suitable transverse frame members B. A pair of supplemental frame plates are secured to the frame members A and support certain parts of the inking mechanism and the repellent applicator, as will hereinafter be more fully described.

Journalled in the frame plate B is the pattern roll shaft ill, on which a suitable pattern roll Ii is drivingly secured. This roll carries on its periphery a planographic printing plate I2, having an image to be reproduced thereon in the usual manner. As shown, the printing plate I2 is removable from the roll II, the end portions of the roll being held within a gap I: in the pattern roll.

The printing plate l2 comprises a comparatively ,thin, flexible, metallic member. One end.

of this plate is first secured to the roll H,- as at i4, after which the plate is wrapped about the periphery of the roll and at the other end is engaged in a suitable manner by a retaining plate l6. The retaining plate It is supported by suitable arms II, which extend into the gap I! in the roll II, and rotatably supported on the shaft I0. Suitable springs M are interposed between-they arm I I and the roll ii, to draw the plate l2 tightly into contact with the periphery of the roll to maintain it taut during the printing operation.

The pattern roll is inked by a suitable inking mechanism. Such inking mechanism may be of any well-known type and is preferably supported in the frame member B. As shown in Fig. l, the inking mechanism comprises an ink fountain having the usual fountain roll 2i. The ink is removed from the fountain roll by a ductor roll 22,

which oscillates between the fountain roll and one roll, and is drivingly mounted on a suitable shaft 3i. An offset blanket 32 composed of rubber or other suitable ink-transferring material is mounted on the periphery of the roll 30 in the same manner as the pattern plate l2 mounted on the pattern roll H. I

The ink pattern or image which is transferred to the offset roll 30 from the pattern roll I! is impressed on or transferred to the material to be printed by such oifset roll. As shown in Fig. 1, a suitable platen roll is drivingly mounted on a shaft 36, which is journalled in the frame plates A. The material to be printed is fed over the surface of a suitableguide table 31 into the bite of the offset roll and the platen 35, and thereby receives the impression from the offset roll. The pattern roll, the ofiset roll, and the platen roll 80. as well as certain rolls in the ink fountain, may be driven in I any well-known manner; Suffice it to say that a'gear I" (Fig. 3) is secured to the pattern roll it and drives the repellent applicator, hereinafter more fully described in detail.

My improved repellent applicator 40 comprises a series of rolls and a fountain, all of which are mounted between a pair of frame plates 4i which are secured to the frame plates B, heretofore mentioned. As shown in Figs. 1,2 and 6, the quantity of repellent, which is a chemical solu-.

tion, is carried in a suitable fountain trough 42. The repellent in the fountain is automatically replenished from time to time, aswlll be hereinafter more fully described. I

Suitable mechanism is provided to transfer the repellent from a fountain 42 to the printing plate i2, in a manner capable of fine adjustment, so that repellents which are required in comparatively small amounts may be applied with a high degree of accuracy. Such repellents are generally chemical solutions, and are usually more viscous than water and slightly acid. These repellents' are transferred from the fountain 42 to the pattern roll in such a manner as to prevent an excess amount of repellent from remaining on the printing plate and in a manner such as will prevent any electrolytic action taking place between the plate and the repellent applicator mechanism, either of which would be detrimental to the accuracy of the reproduction.

Mounted with the lower edge in the fountain 42 is a fountain roll 43. This roll is preferably a metallic 'roll having a knurled or otherwise roughened surface. This roughened surface enablestheroll consequent upon its rotation to pick a quantity'of repellent from the fountain and carry it"upwardly on its surface, so that it may be transferred to a suitable ductor roll 44. As hereinafter described, this roll 43 is intermittently given step by step rotation, with short periods of rest, permitting surplus liquid to drain from it;

The ductor roll 44 preferably comprises a nonmetallic or composition roll. The roll is mounted pair of arms 41, carried by a shaft 45, which,

in turn, is journalled in the frame plate mem- The shaft 46 is oscillated to cause the ductor roll 44 to alternately move in contact with the fountain roll 43 and a suitable distributor roll 48. The ductor roll is made of insulating material and therefore prevents any electrical circuit being formed between the fountain roll and other rollers in contact with the ductor. The distributor roll 48 is preferably, as heretofore mentioned, a smooth surfaced roll, such roll may be a metal roll for purposes heretofore set out. The distributor roll 48 is carried by a suitable shaft 49, which is mounted in the frame plate 4| and serves to transfer the repellent to a form roll 50, which is rotatably mounted on a suitable shaft 5| carried by the frame plate 4!.

The form roll v5i] preferably comprises, for

purposes heretofore set out in detail, a resilient, smooth-surfaced, non-liquid-absorptive roller) .on a shaft 46 journalled in the upper end of a comparatively great.

'52, which is journalled in a bushing 53.

circuit between the metal distributing roll 48 and the pattern plate l2. It will be noted that the roll 58 is larger in diameter than the roll 48, and hence the peripheral distance on the roll 58 between its line of contact with the printing plate and its line of contact with the distributing roll is I find that this distance, together with the fact that only a small quantity of repellent is carried by the roll 58, causes the resistance of the repellent solution to electrical energy to be so great as to prevent practically any transmissal of electrical energy from the distributor roll .48 to the plate l2.

' As shown, the form roll has a smooth, resilient surface, with no liquid absorbing qualities, and the metallic distributor roll presents a smooth surface to ink which may remain on the surface of the form roll after its contact with the pattern. I have found that by. so arranging such rolls,the surface characteristics thereof prevent the. accumulation of any undue amount of ink on the form roll, or the transfer of such ink to the distributor roll, thereby eliminating the necessity of cleaning the rolls at frequent intervals. Likewise, if cleaning is desired, such smooth, non-liquid-absorbing surfaced rolls are readily cleaned without removing them from the pressan advantage lost when fabric covered rolls are used. At the same time, the distributor roll acts to smooth out any ink which is transferred to the form roll 58 by the printing plate and so dis- 'tributes it that when it is reapplied to the plate it will not disturb the evenless of the film of ink to be applied by the inking mechanism.

. As shown in Figs. 3 and 4, the fountain roll 43 and the form roll 58 are positively driven. The form roll 58 is rotatably journalled on a shaft one end of which has an eccentric portion The other end has an eccentric stub 54, which is journalled in a bushing 55 secured to the frame plate 4| by means of a suitable screw 58. Thus, by rotating the shaft by means of a knob 88, the shaft may be adjusted to'move bodily to or from the printing plate l2, thereby regulating the pressure between the roll 58 and the printlng plate or pattern l2.

As shown in'F ig. 3, the left-hand end of the shaft is provided with a series of notches or recesses 58, which coact with a spring-pressed plunger 59, so that the shaft may be readily positioned to any one of a number of predetermined positions, thereby enabling the pressure of the roll on the printing plate to be regulated. This arrangement also retains the shaft in'the desired position. The bushing 53 which is eccentrically mounted in the frame and is given a partial rotation to raise or lower the left-hand end of the shaft 5|, thereby permitting the operator to align the roll 58 accurately with the printing plate l2, so as to enable the entire length of the roll to contact evenly with the plate. A suitable screw 6| secures the bushing in place once it is adjusted.

The adjustment of the roll 58 by turning the shaft 5| regulates the amount of repellent left on the plate by varying the squeegee action of the roll. This permits the feeding of an excess amount of repellent to theroll 58 to insure a thorough dampening of the plate with the repellent, while at the same time limiting the amount of repellent actually deposited on the plate. The excess repellent forms in a bead or wave extending along and in front of the line of contact between the roll 58 and the plate. Such excess may drop into the gap in the drum where it may be absorbed by any suitable absorbent material, such as is indicated at 18!, Fig. 1.

'As the roll 58 acts on the plate as a squeegee. it is obvious that it may likewise act as a squeegee on the hard surfaced distributor roll 48. Ordinarily, this latter squeegee action could, for all practical purposes, be disregarded. However, I contemplate the use of my repellent applicator in oilice printing equipment which, for the most part, will be operated by non-professional or inexperienced help. Therefore, provision should be made for the disposal of any excess repellent line of contact repellent at the bite of the rolls 48 and 58, I find that the repellent may be unevenly distributed to the plate by the form roll 58. If this excess is permitted to continue for-a material period of time,'it may flow to the plate around the surface of the roll 58 in a reverse direction despite the direction of rotation of the roll. In such instances, the repellent would drop to the surface of the plate between the repellentapplicator and the inking mechanism. The plate, therefore,

-would have an excess amount of repellent distributed unevenly, over its surface, resulting in a faulty application of ink, as well as lessening the resistance to electrical energy of the film of repellent on the roll 58, by bridging the gap between the plate and the'distributor roll with a heavy film of repellent.

To prevent accumulation of repellent before the line of contact between the rolls 4,8 and 88, I prefer to periodically raise the roll 48 from contact with the roll 58, and thereby permit any excess repellent to be distributed around the periphery of the rolls 48 and 58. As shown in Fig. 4'. the roll 48 is mounted in bearings 8, which are slidably mounted in ways II I, in the frame members 4|, so that this roll may slide in the frame upwardly, out of contact with the roll 88 and in such a manner that it will likewise be moved out of contact with the ductor roll 44, while the latter is in contact with the fountain roll. To effect the periodic raising and lowering of the roll 48, I prefer to provide, as shown in Fig. 2, a pair of levers or arms H2, which are rigidly secured to the shaft 45, heretofore described, and the outer ends of which are arranged to engage flanges H4,- carried by the roll 48. The rocking movement of the shaft 48 hereinafter described in detail serves to periodically raise the roll 48 in the direction of the arrow in Fig. 2, the weight of the roll retaining it in contact with the arms H2. arrangement prevents the accumulation of an undue amount of repellent between the rolls 48 and 88.

The roll 58 is driven from the pattern roll ll through the medium of a gear I88, heretofore mentioned. As shown in Fig. 3, the gear I88 meshes with a gear 18 of a composite gear mem- I find that such an.

her which is journalled on the bushing II. and which is drivingly connected with the roll ll, through the medium of an Oldham coupling H. The inter-engaging portions of the coupling ll have suillcient lost motion to permit the roll W to be driven, under frictional influence with the printing plate I! and at a slightly greater speed than the positive drive of the gear. The'roll ll ispositively driven across the gap of the pattern roll to secure a fresh supply of repellent at all times, but when in engagement with the plate and which is rigidly secured to the ductor roll supporting shaft 45. A suitable spring I interposed between the other arm of the bell crank '66 and a relative stationary part of the mechanism maintains the roller 63 in contact with the periphery of the cam 62. v

The cam 62 is driven by the gear I00, heretofore mentioned. The gear liill meshes with a gear 10 of a composite gear member, which also carries a gear member I2 meshing with a gear I3, which is secured to a stub-shaft I4 journalled in a suitable bushing carried by the frame member II. A suitable gear 15 is rigidly secured to the stub shaft 14 and meshes with a gear 16. which is drivingly secured to or integral with the cam member 62, thereby rotating the cam member.

The fountain roll 43 is intermittently given a partial rotation by the gear I6. As shown in Fig. 4, the fountain roll 6|, Figs. 2 and 4, is rigidly secured toa shaft 80, journalled in the frame member 4 I. Secured tothe outer end of the shaft is a ratchet 8| which is intermittently advanced by a pawl 82, carried by a plate 83, which is rotatably mounted on the shaft 80. Suitable links 84 are connected at one end to the plate 83 and at the other end to a pin 85 eccentrically carried by the gear I6. In this manner the pawl is intermittently driven to advance the ratchet a number of teeth at a time. A suitable spring 81, Fig. 4, serves to maintain the pawl in contact with the ratchet.

The amount of movement imparted to the ratchet wheel 8| is controlled, to thereby regulate the amount of repellent transferred to the ductor roll 44 from the fountain roll 43. As shown, a cam disk 90 is rotatably secured to the shaft 80 and is provided with a cam surface 9|, which cooperates with a pin 92 on the pawl 82, to disengage the pawl from the ratchet at a predetermined point in the movement of the plate 83.

A spring pressed plunger 93 engages notches in the disk 90 and maintains the disk in any one of several adjusted positions, whereby the position of the cam surface 9i may be adjustably positioned to change the effective stroke of the pawl 82. A lever 95 is secured to the disk 90 to enable the operator to readily vary the effective stroke to the pawl- 82, as more or less repellent is required.

I have found it desirable, because of the chemical characteristics of the repellent, to provide a repellent fountain or trough. such as is shown in Figs. 1 and 5, and which will retain a comparatively small amount of fluid. I also find it advisable to arrange the trough so that the repellent may be automatically replenished and the level of the fluid in the trough maintained substantially constant. For this p rpose I provide the trough with an upstanding tubular portion Stas shown in Fig. 5, the lower end of the tube opening into the trough. as at 91. The upper end is provided with suitable formation 98 to engage the neck of "a bottle or suitable storage reservoir or container 9 9. Hence, as soon as the repellent is lowered below the bottom line of the tubular portion '96 of the trough. air will be admitted to the container 39 and will replace sufficient repellent to bring the level of the trough substantially to the bottom line of the tube '90.

It will be seen from the foregoing description that by my invention liquid repellent is supplied to the plate, before it reaches the first acting inking form roller, by means of a repellent applicator roll which supplies the plate with a predetermined amountof repellent, regardless of the amount of repellent transferred to the applicator roll, and such repellent roll is provided with a non-absorptive surface so that it will not act as a reservoir for liquid repellent. Because the roller is made of a resilient non-absorptive material it may be pressed against the printing plate to act as a squeegee roller to remove excess repellent; because of its insulating qualities, the roller itself cannot act as a pole for an electrolytic cell; because of its non-absorptive qualities and diameter it so increases the resistance .of the electrolyte on its surface that for all practical purposes it prevents the formation of an electrolytic cell; because of its smooth surface it does not affect the evenness of the layer of ink remaining on the printing image after the impression has been made andthereby permits even distribution of ink by the inking system; and because of the smooth surface of such roller, together with the smooth surface of its distributor or coacting roller, any ink removed from the image by the applicator roller is evenly redistributed to the printing plate. I

I claim:

1. In a planographic press wherein the imagecarrying member comprises a metallic plate, one dampening roller in contact with such printing plate, said roller having a surface of a material which is resilient and at the same time nonabsorptive, and means for adjusting the pressure of said roll against the plate to cause a squeegee action.

2. A planographic press having an impression member, a liquid repellent applicator roller in contact with the impression member, said roller having a smooth resilient surface, a metallic distributor roller in contact with said applicator roller and adapted to supply the applicator roller with liquid repellent, said distributor roller having a smooth surface, and means for adjusting the pressure of the applicator roller against the plate to cause said roller to have a squeegee action on the plate.

3. In a planographic printing machine, the combination of a repellent reservoir, a fountain roll depending into the reservoir, positive means for giving the fountain roll partial rotations, means for carrying a printing plate, a non-metallic form roll having a smooth, flexible, nonabsorbing surface pressed against the plate with a squeegee pressure, a metallic distributor roll having a smooth surface engaging the form roll, and a smooth surfaced non-metallic ductor roll between the fountain roll and the distributor roll.

4. In a planographic printing machine having a planographic printing plate, a. liquid repellent applicator. system, saidsystem including a metallic distributor roll, a ductor roll mounted to periodically move intoand out of contact with the distributor roll to transfer liquid repellent thereto, a repellent applicator roll arranged to contact with the plate to supply repellent thereto, said repellent applicator roll being normally in contact with said distributor roll, and means to periodically move the distributor roll out of contact with the repellent applicator roll.

5. In a planographic printing machine, having a planographic printing plate, a liquid repellent applicator system, said system including a repellent fountain, a fountain roll coacting with such fountain, a metallic distributor roll, a

ductor roll mountedto swing from contact with the fountain roll to contact. with the distributor roll to transfer liquid repellent from the fountain to the distributor roll, a resilient surfaced form roll or repellent applicator roll arranged to contact with the plate to supply repellent thereto, said repellent applicator roll being normally in contact with said distributor roll, and means to periodically move. the distributor roll out of contact with the repellent applicator roll.

6. The combination with a planographic printing press having a printing plate, and means for feeding the liquid repellent to the printing plate, said means comprising a smooth-surfaced form roll in contact with the printing plate, a smoothsurfaced distributor roll adapted to feed the repellent to the form roll to distribute repellent thereto, a ductor roll, said ductor roll adapted to supply the distributor roll with repellent, means to periodically move the ductor roll out of contact with the distributor roll, and means to periodically move the distributor. roll out of contact with the form roll and the ductor roll simultaneously.

7. The combinaion with a planographic printing press having a printing plate, said plate having image and non-image bearing areas, the nonimage bearing areas being treated to prevent adhesion oi ink thereto, and means for continuously feeding liquid repellent to the printing plate, said means comprising a rubber surfaced roller in contact with the printing plate, a hard surfaced distributor roller adapted to feed the repellent to said rubber surfaced roller, a ductor roller adapted to supply the distributor roller with repellent, means to periodically move the ductor roller out oi contact with the distributor roller, and means to periodically move the distributor roller out of contact with the rubber surfaced roller and theductor roller.

8. In a planographic printing machine having a printing plate, a liquid repellent applicator system, said system including a .rubber surfaced squeegee roller in contact with the printing plate, and means comprising a metallic roller to supply a film of liquid repellent to said squeegee.

9. A planographic press wherein the imagecarrying member comprises a metallic plate, and there is a resilient dampening roller in contact with the printing plate, said roller having a surface of a material which is a non-conductor oi electric energy and'is non-absorptive and said roller being pressed against the plate with suillcient pressure to cause the roller to act as a squeegee to remove excess liquid from the plate, a metallic roller contacting with the dampening roller, and means for keeping the metallic roller supplied with more liquid than the'plate needs.

10. The method of planographic printing comprising suppiying an excess of liquid repellent by means of a metallic roller to aresilient nonabsorbent roller contacting therewith, while said non-absorbent roller is having a rolling contact with the plate, and causing such pressure of the non-absorbent roller against the plate-as will cause it to act as a squeegee to remove the excess repellent from the plate.

HENRY C. OBBORN.

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