GB1590928A - Inking device - Google Patents

Description

(54) IN KING DEVICE (71) I, JOHN GROSART, a Canadian subject, of 14 Benedict Road, Islington, Ontario, Canada, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a device for use in applying ink or other liquid to a printing surface. For convenience of description reference is herein confined to the application of ink. However, it is to be understood that the device of the invention may be used for applying other liquids, for example, lacquers and water.

In many conventional printing techniques, ink is applied to a printing surface from a trough in which a cylinder (or roller) rotates.

The printing surface may be the peripheral surface of the cylinder itself or the cylinder may transfer the ink to a remote printing surface. This method of applying ink from a trough has numerous disadvantages. For example, such cylinders are often necessarily of substantial length. Since support rollers cannot conveniently be provided where an ink trough is used, sagging of the cylinder (known as "cylinder deflection") may be a problem. Also, where the cylinder is an impression cylinder, an impression can be taken only from the top of the cylinder, which has the disadvantage that gravity acts against transfer of ink to the paper being printed.

Further, only one trough can be used with each cylinder with the result that only one impression can be taken per cylinder.

The present invention has been devised in connection with rotogravure printing (although the invention is not limited by this).

Rotogravure is an intaglio printing technique in which the design to be printed is formed by recessed ink-carrying cells in the curved surface of a printed cylinder. The cells are arranged in the pattern of the design to be printed. Conventionally, the cylinder rotates in a trough of ink which floods the surface of the cylinder. A doctor blade positioned above the trough wipes excess ink off the cylinder so that the cells remain filled with ink for subsequent transfer to a web or sheet to be printed.

An object of the present invention is to provide an improved device for applying ink or other liquid to a printing surface (as defined hereinbelow).

According to the invention, such a device comprises a body in the form of an elongate one-piece extrusion defining two spaced limbs extending longitudinally of the extrusion, and a central formation intermediate said limbs and defining with said limbs two longitudinally extending slots; two flow control blades having respective inner portions received in said slots in the body, said limbs of the body clamping the blades against said central formation, and the blades projecting from the body to define a chamber for said ink or other liquid with the body and parallel outer edges for contact with said printing surface in use; sealing means located at respectively opposite ends of the blades to define ends of said chamber; and inlet means in the body for delivery of said ink or other liquid to said chamber; whereby when the device is arranged in use with the blades in contact with said printing surface and spaced from one another, said ink or other liquid flows from the chamber between the blades and onto said printing surface.

The invention will be better understood by reference to the accompanying drawings which illustrate various embodiments of the invention by way of example. In the drawings: Fig. 1 is a perspective view from one end of an inking device according to the invention; Fig. 2 is a vertical cross-sectional view through the device of Fig. 1, showing the device in use; Fig. 3 is an exploded vertical sectional view through the device of Figs. 1 and 2 and illustrates a step in the manufacture of the device; Fig. 4 is a view similar to Fig. 3 showing the device in the fully assembled condition; Fig. 5 is a view similar to Fig. 4, showing a modified form of device; Fig. 6 is a plan view, partly in section, of the device of Fig. 4; Fig. 7 is a transverse cross-sectional view on line VII--VII of Fig. 6; and, Fig. 8 is a sectional view similar to Fig. 16 through the modified device of Fig. 5.

The inking devices shown in the drawings are intended primarily for use in gravure printing and are designed as non-adjustable throw-away units. The devices include inkflow control blades which are pre-set and non-adjustable. When the blades of a device become worn or the device ceases to function efficiently, it will be discarded and replaced as a unit. This avoids the problem associated with the doctor blades used in conventional printing installations which require to be sharpened periodically and adjusted to obtain optimum performance.

Figs. 1 to 4, 6 and 7 show the same device.

This device has self-closing blades and is intended for use in a situation in which the inking device is required to operate intermittently. Intermittent operation may be required, for example, where the device is used in a flat bed printing machine in which the device moves over a printing surface, is raised from the surface, and returned to a starting position clear of the surface. Another example of a situation in which intermittent operation is required is where the device is used in association with an off-set printing cylinder having a gapped printing surface. The device may simply "jump" the gap as the cylinder turns, or it may be lifted clear of the printing surface just before gap approaches, and returned to the printing surface after the gap has passed. In any event, it is necessary that the blades of the inking device shall close to prevent ink leaking from the device when it is out of contact with the printing surface. The device of Figs. 5 and S is essentially similar except that the blades áre not seif-ciosing. A device of this form is nténded for use in a continuous mode in which the blades are always in contact with the printing surface.

Referring first to Figs. 1 to 4, the device ds a whole is generally denoted 226 and includes a body 228 and two flexible blades 230 and 232; blade 232 is the leading blade in this case. The blades are made of relatively thin sheet steel, although in alternative embodiments the blades may be made of a suitable elastic material or combinations or laminations of plastic steel. Body 228 is in the form Of an extrusion. In this embodiment, the extrusion is aluminium although there is no limitation to this particular material. In other cases, it would even be possible to use plastic inaterials-for the body.

.Fig. 2 shows the device of Fig. 1 in use in association with a printing cylinder. The device is mounted adjacent the cylinder with the outer end portions of the blades 230 and 232 in contact with the surface of the cylinder.

The blades are normally closed, but open on contact with a printing surface so that ink can flow from the device onto the surface.

The device is mounted in a support assembly (see later) so that it can be moved between the "on" position in which it is shown for applying ink to the printing surface, and an "off" position clear of the surface in which the blades are closed and the supply of ink to the printing surface is thereby cut off. In any event, it will be appreciated that, in the "on" position in which the device is shown in Fig. 2, ink is applied to the printing surface between the blades and that blade 230 (the "trailing" blade considered in the direction of cylinder rotation) acts as a doctor blade to wipe surplus ink from the surface of the cylinder.

Fig. 3 shows the cross-sectional shape of the extrusion used to form the body 228.

The extrusion includes a main body portion 234 having a generally V-shaped groove 236 along one longitudinal edge. The opposite longitudinal edge of body portion 234 is shaped to define a central formation 238 and two side limbs 240 and 242, all of which extend longitudinally of body portion 234.

Limbs 240 and 242 define with formation 238, two longitudinally extending slots which receive the blades 230 and 232. Formation 238 defines a semi-circular section recess 244 having inner limbs 246 and 248 extending along opposite sides thereof. It will be noted that limb 248 is of significantly greater length than limb 246.

The outer limbs 240 and 242-of the extrusion are joined to the body portion 234 by narrow "neck" portions 250 and 252 respectively. Respective generally circular-shape passageways 254 and 256 are provided adjacent these "necks" and between the respective inner and outer limbs 246, 240 and 248, 242. In the extrusion as manufactured, the limbs 240 and 242 are outwardly angled as shown in Fig. 3. However, as a result of the narrow 'heck" portions 250 and 252, the limbs 240 and 242 oan be bent inwardly as indicated by the arrows 258 and 260 to co-operate with the inner limbs 246 and 248 of the central formation 238 and trap the blades 230 and 232 in the body 228 of the inking device.

In Fig. 3, the blades 23,0 and 232 are shown in exploded positions prior to insertion into the body of the device. Thus, the blades are introduced into the slots defined by the limbs 240 and 242 and the central formation 238 until the inner edges of the blades contact the walls of the respective passageways 254 and 256. The blades are dimensioned so that they are correctly positioned when fully inserted.

The outer limbs 240 and 242 are then deflected inwardly in the directions of arrows 258 and 260 so that the blades are clamped between the respective inner limbs 262 and 248 of formation 238 and the outer limbs 240 and 242. If necessary, cement can be applied to the co-operating faces of the respective limbs and/or to the blades, before the limbs 240 and 242 are deflected. Fig. 4 shows the assembled device. The blades 230 and 232 are shown in full lines in their normal closed positions and in chain dotted lines in their open positions for applying ink to a printing surface as discussed above.

It will be noted from Fig. 4 that the respective outer limbs 240 and 242 have inwardly angled outer end portions 262 and 264. These portions engage the blades 230 and 232 respectively and cause them to adopt the curved configurations shown in full lines, in which the outer longitudinal portions of the blades contact one another and define with the body 228 a sealed ink chamber 266. It will also be noted from Fig. 4 that the outer end portion 262 of limb 240 is longer than the corresponding portion 264 of portion 242; in fact, portion 262 terminates substantially on the median plane MP of the extrusion.

Portion 262 defines a pivot for the trailing blade 230 so that the volume of the ink chamber 266 remains substantially constant when the blades move between their open and dosed positions as the device moves between its "on" position and its "off" position as discussed previously in connection with Fig.

2. 'Thus, the curvature of the inner portion of blade 230 betweeh portion 262 and the inner end portion of the blade increases significantly when the device is moved from the "off" position to the "'own" position. This compensates for the increase in volume of ink chamber 266 which would otherwise occur as the outer ends of the blades open due to contact with the printing surface, with the result that the volume of ink chamber 266 remains substantially constant in both the "on" position and the "off" position of the device. This avoids or at least minimizes any increase in pressure in chamber 266 as the device moves between the "on" and "off" positions, which could cause leakage of ink between the blades. Also, the outer edge of the leading blade 232 extends slightly beyond the corresponding edges of the trailing blade 230. This ensures that the outer edges of both blades make contact with a printing surface when the blades are open. The fact that portion 262 of limb 240 is slightly longet than the corresponding portion of the other limbs of the extrusion allows two blades of the same length to be used while maintaining this differential in spacing between the outer edges of the blades.

In the iembodiment shown in Fig. 5, primed reference numerals have been used to denote parts which correspond with parts shown in Figs. 1 to 4. As explained above, the device shown in Fig. 5 differs from the device of the previous-figures in that the blades are not self-closing. In the 'extrusion of Fig. 5, the inner and outer limbs 2481 and 2421 respectively of the body 2281 are significantly shorter than the corresponding limbs of the extrusion shown in Fig. 4, and limb 2421 has no inwardly directed outer end portion. Also, limb 240, is shorter overall and has a shorter outer end portion 262, than the corresponding parts of the extrusion shown in Fig. 4. Accordingly, the blades 2301 and 2321 in the Fig. 5 embodiment are always open. In that view, the blades are shown in full lines in their inoperative positions and in chain dotted lines in their operative positions in which they are in contact with the printing surface.

Ink is delivered to and, if necessary, removed from the ink chamber 266 by passageways 268 provided in the body 228 of the device and extending from the V-shaped groove 236 to the semi-circular recess 244 of the extrusion (see Fig. 2). As indicated in that view, the outer ends of these passageways may be internally screw threaded and fitted with unions 270 to which pipes 272 can be coupled. In a typical inking device, two passageways 268 would be provided adjacent opposite ends of the body 228. However, additional passageways could obviously be provided if necessary, for example, where the device is of unusual length.

It will also be noted from Fig. 2 that a groove 274 is provided in one side face of the body 228 of the device. The primary purpose of groove 274 is to serve as an indication as to which way the device is intended to face when fitted to a printing machine. However, the groove may also serve to facilitate location of the device in a support assembly such as that indicated in chain line at 276 in Fig. 2.

In the illustrated embodiment, assembly 276 will be designed to allow movement of the inking device between an "off" position clear of the printing cylinder and the "on" position in which the device is shown, for applying ink to the cylinder as discussed previously.

Assembly 276 may form part of the doctor blade assembly normally provided in a conventional gravure printing machine, from which the doctor blade itself has been removed. However, it is to be understood that the inking devices may be supported in any convenient fashion. In the simplest case, all that is required is a clamping arrangement for holding the device.

Referring to Fig. 1, end seals 278 and 280 are provided at opposite ends of the device for sealing off the ink chamber 266. These seals will now be more specifically described with reference to Figs 6 and 7. In Fig. 6, part of the device has been broken away adjacent end seal 278 to show the seal in section. Part of the trailing blade 230 of the device is visible in the sectioned portion of Fig. 6 as is part of the body 228 formed with an ink passageway 268. A body 282 of a resilient sealing material is applied to the end face 284 of the body 228 of the device. It will be noted that the blades 230 and 232 protrude slightly beyond face 284 as indicated at 296. The protruding end portions of the blades are embedded in the sealant body 282. The sealant body also includes an inwardly extending portion 288 disposed on the exterior surfaces of the blades 230 and 232. As a result, the sealant body has a somewhat L-shaped appearance when viewed from externally of the device as can be seen more clearly in the case of the seal arrangement 280 in Fig. 6.

Applied to the portion 288 of the sealant body on the exterior surfaces of the blades 230 and 232 is a pad 290 of a low-friction material. In this embodiment, pad 290 is made of Teflon (Registered Trade Mark) and the sealant is a silicone sealant, suitable examples of which are available from Dow Corning and General Electric. The pad 290 and a similar pad 292 at the other end of the device are in contact with the printing surface when the device is in use and ensure that the ink applied by the device is confined between the end seals.

Blade 230 is formed with a short slot 294 at a position spaced inwardly to a slight extent from its outer edge 286. The slot extends in the transverse direction of the blade; that is, normal to its outer edge 296. A similar slot is formed in the other blade 232 but this is not visible in Fig. 6. The Teflon pad 290 is formed with a slot 298 which is in line with the edges of the blades 230 and 232 and which extends from the inner end of the pad to a position just beyond the slot 294. The Teflon pad 290 is arranged so that the portions of the blades inwardly of the slots 294 protrude through the slot in the pad with their outer edges substantially even with the outer surface of the pad. The "corner" of blade 230 outwardly of slot 294, denoted 300, and the corresponding part of blade 232 are curved to a greater extent than the remainder of the blades and bear against the inner surface of the Teflon pad as can be seen in Fig. 7.

The "corner" portion of blade 232 is denoted 302 in that view. These portions of the blades urge the Teflon pad against the printing surface when the device is in use to maintain a seal between the pad and the printing surface.

The space between the blades 230 and 232 adjacent to the body 282 of sealant is filled with a grease as indicated at 304. The purpose of the grease is to minimize the degree of contact between the ink in the device and the sealant. The grease is retained in the area adjacent the sealant by a brush-like body of cotton fibres 306 retained by cement in a small bore 308 in the aluminium body 228. The cotton fibres 306 extend outwardly from the aluminium body generally to the inner surface of the Teflon pad 290. In this embodiment, the grease 304 is a conventional automotive grease although other suitable materials could be used. Also, materials other than cotton fibres 306 could be used to provide a barrier for retaining the grease. An example of a suitable material would be a foam plastic.

While the end seal arrangement 278 has been specifically described, it is to be understood that seal 280 is similar.

Fig. 8 is a view similar to Fig. 7 showing the device of the form described with reference to Fig. 5 in which the blades of the device are not self-closing. The end seal arrangement used in this embodiment is essentially the same as that in the embodiment of Figs. 6 and 7 and primed reference numerals have been used in Fig. 8 to denote parts corresponding with the previous views.

However, in view of the similarity between the two arrangements, it is believed to be unnecessary to describe Fig. 8 in detail.

It should of course be noted that the preceding description applies to specific embodiments of the invention and that many modifications are possible within the broad scope of the invention.

For example, although the inking devices have been described in use in connection with rotogravure printing machines, it is to be understood that there is no limitation in this. Thus, the devices could also be used for flat bed printing machines, rotary letterpress type machines converted to gravure printing and to replace the ink troughs on Flexographic machines. Inking devices as described above may also be applied to screen stencil printing. In fact, it is believed that the device of the invention may be used in any situation in which ink is to be applied either to a flat surface or to an intaglio type of surface in which the ink carrying part of the surface is recessed. Where the surface is flat, it may be necessary to balance ink pressure with the blade pressure to cause ink to be applied to the printing surface. Of course, the inking device need not apply the ink directly to a surface from which an impression is taken.

The ink could be applied to an inking roller from which the ink would be transferred to the impression surface. Accordingly, the term "printing surface" as used in this specification and in the claims is to be interpreted as including any surface to which ink is applied.

In any arrangement in which the printing surface has a gap, appropriate means will normally be provided to cause the inking device to "jump" the gap. These means may take a variety of forms, such as those operated by means of cams, pneumatics, hydraulics or electrics.

Where an inking device according to the invention is used in a situation in which the device is always in contact with the printing surface, the self-closing blade feature is not necessary. In this event, the device would not have to be moved out of contact with the printing surface to terminate delivery of ink to the surface. It would merely be necessary to cut off the supply of ink to the device.

It is also to be understood that an inking device of the form provided by the invention may be located at any position around a cylinder to which ink is to be applied. Moreover, more than one inking device may be used in association with a single cylinder.

For example, two or more devices each supplying a different coloured ink could be used.

The devices could be positioned at different angular locations around the cylinder or they could be arranged at different axial positions along the length of the cylinder.

A multiple inking device arrangement may also be used to simultaneously take several impressions from one cylinder. For example, two or more webs may be run in contact with a single cylinder with an inking device arranged in advance of the point of contact of each web with the cylinder, thereby doubling or more the productivity of the press without increasing the speed.

The above examples are not necessarily exhaustively described since it is believed that the wide range of possible applications of the device will be readily appreciated by a person skilled in the art.

As is customary in conventional gravure doctor blade installations, provision may be made to continuously oscillate the inking device in the axial direction of the cylinder in association with which it is used. Such oscillation may be derived from a suitable low speed high torque motor coupled with the device through an appropriate mechanical arrangement designed to additionally allow movement of the device towards and away from the associated cylinder as described above.

Further, in some instances, it may be desirable to additionally provide a reverse doctor blade in association with the printing cylinder in advance of the inking device in order to remove from the cylinder "hickeys" (paper particles) and other foreign material which may be picked up from the web to avoid contaminating the ink applied by the inking device.

WHAT I CLAIM IS: 1. A device for applying ink or other liquids to a printing surface (as defined hereinbefore), the device comprising: a body in the form of an elongate onepiece extrusion defining two spaced limbs extending longitudinally of the extrusion, and a central formation intermediate said limbs and defining with said limbs two longitudinally extending slots; two flow control blades having respective inner portions received in said slots in the body, said limbs of the body clamping the blades against said central formation, and the blades projecting from the body to define a chamber for said ink or other liquid with the body and parallel outer edges for contact with said printing surface in use; sealing means located at respectively opposite ends of the blades to define ends of said chamber; and inlet means in the body for delivery of said ink or other liquid to said chamber; whereby when the device is arranged in use with the blades in contact with said printing surface and spaced from one another, said ink or other liquid flows from the chamber between the blades and onto said printing surface.

2. A device as claimed in claim 1, wherein said extrusion includes a main body portion and two relatively narrow longitudinally extending neck portions coupling said two spaced limbs to said body portion, the extrusion being formed with said limbs in outwardly angled positions and said neck portions allowing the limbs to be deflected inwardly to clamp said blades against said central formation.

3. A device as claimed in claim 1, wherein said two spaced limbs define outer limbs of the extrusion, and wherein said central formation defines inner limbs extending parallel to said outer limbs and defining therewith said slots receiving the blades, and wherein each of said outer limbs has an inwardly directed outer and portion arranged to contact and inwardly deflect the associated blade, and wherein said inner limbs are dimensioned to co-operate with the respective outer limbs to determine the inward curvature of the blades.

4. A device as claimed in claim 3, wherein said blades are normally closed and are resiliently deflectible upon contact with said printing surface in use to open and allow said ink or other liquid to flow onto said printing surface, and wherein one of said blades is a leading blade and the other blade is a trailing blade considered in the direction of relative movement between the device and said printing surface in use, and wherein the outer limb of the extrusion associated with said trailing blade engages the blade at a position intermediate its said inner end portion and its outer edge and defines a pivot arranged to cause the portion of the blade between its said inner end portion and said pivot to curve inwardly as the blades open upon contact with said printing surface so that the volume of the chamber remains at least substantially constant.

5. A device as claimed in claim 1, wherein said sealing means comprise , at each end of said extrusion, a body of a resilient sealant adhered to said blades and extrusion and closing the relevant end of the chamber, said body of sealant including an inwardly extending portion enclosing an outer end

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. have to be moved out of contact with the printing surface to terminate delivery of ink to the surface. It would merely be necessary to cut off the supply of ink to the device. It is also to be understood that an inking device of the form provided by the invention may be located at any position around a cylinder to which ink is to be applied. Moreover, more than one inking device may be used in association with a single cylinder. For example, two or more devices each supplying a different coloured ink could be used. The devices could be positioned at different angular locations around the cylinder or they could be arranged at different axial positions along the length of the cylinder. A multiple inking device arrangement may also be used to simultaneously take several impressions from one cylinder. For example, two or more webs may be run in contact with a single cylinder with an inking device arranged in advance of the point of contact of each web with the cylinder, thereby doubling or more the productivity of the press without increasing the speed. The above examples are not necessarily exhaustively described since it is believed that the wide range of possible applications of the device will be readily appreciated by a person skilled in the art. As is customary in conventional gravure doctor blade installations, provision may be made to continuously oscillate the inking device in the axial direction of the cylinder in association with which it is used. Such oscillation may be derived from a suitable low speed high torque motor coupled with the device through an appropriate mechanical arrangement designed to additionally allow movement of the device towards and away from the associated cylinder as described above. Further, in some instances, it may be desirable to additionally provide a reverse doctor blade in association with the printing cylinder in advance of the inking device in order to remove from the cylinder "hickeys" (paper particles) and other foreign material which may be picked up from the web to avoid contaminating the ink applied by the inking device. WHAT I CLAIM IS:

1. A device for applying ink or other liquids to a printing surface (as defined hereinbefore), the device comprising: a body in the form of an elongate onepiece extrusion defining two spaced limbs extending longitudinally of the extrusion, and a central formation intermediate said limbs and defining with said limbs two longitudinally extending slots; two flow control blades having respective inner portions received in said slots in the body, said limbs of the body clamping the blades against said central formation, and the blades projecting from the body to define a chamber for said ink or other liquid with the body and parallel outer edges for contact with said printing surface in use; sealing means located at respectively opposite ends of the blades to define ends of said chamber; and inlet means in the body for delivery of said ink or other liquid to said chamber; whereby when the device is arranged in use with the blades in contact with said printing surface and spaced from one another, said ink or other liquid flows from the chamber between the blades and onto said printing surface.

2. A device as claimed in claim 1, wherein said extrusion includes a main body portion and two relatively narrow longitudinally extending neck portions coupling said two spaced limbs to said body portion, the extrusion being formed with said limbs in outwardly angled positions and said neck portions allowing the limbs to be deflected inwardly to clamp said blades against said central formation.

3. A device as claimed in claim 1, wherein said two spaced limbs define outer limbs of the extrusion, and wherein said central formation defines inner limbs extending parallel to said outer limbs and defining therewith said slots receiving the blades, and wherein each of said outer limbs has an inwardly directed outer and portion arranged to contact and inwardly deflect the associated blade, and wherein said inner limbs are dimensioned to co-operate with the respective outer limbs to determine the inward curvature of the blades.

4. A device as claimed in claim 3, wherein said blades are normally closed and are resiliently deflectible upon contact with said printing surface in use to open and allow said ink or other liquid to flow onto said printing surface, and wherein one of said blades is a leading blade and the other blade is a trailing blade considered in the direction of relative movement between the device and said printing surface in use, and wherein the outer limb of the extrusion associated with said trailing blade engages the blade at a position intermediate its said inner end portion and its outer edge and defines a pivot arranged to cause the portion of the blade between its said inner end portion and said pivot to curve inwardly as the blades open upon contact with said printing surface so that the volume of the chamber remains at least substantially constant.

5. A device as claimed in claim 1, wherein said sealing means comprise , at each end of said extrusion, a body of a resilient sealant adhered to said blades and extrusion and closing the relevant end of the chamber, said body of sealant including an inwardly extending portion enclosing an outer end

portion of said outer edges of the blades; and a pad of a low friction material adhered to said inwardly directed portion of the sealant body and arranged for contact with said printing surface over which the device moves in use, and wherein each of said blades includes an outer edge portion disposed inwardly of said pad of low friction material and arranged to bias said pad into contact with said printing surface in use.

6. A device as claimed in claim 5, further comprising barrier means disposed in said chamber adjacent each of said sealant bodies for minimizing contact between said ink or other liquid in said chamber and said sealant body, each said barrier means comprising a barrier liquid which is immiscible with said ink or other liquid to be used in the device, and which is disposed in the chamber adjacent the sealant body, and retaining means coupled to said body of the device and arranged to retain said barrier liquid in the end portion of the chamber.

7. A device for applying ink or other liquid to a printing surface (as defined hereinbefore), substantially as hereinbefore described with reference to and as illustrated in any one of the accompanying drawings.