Printing Inking Members

Abstract

A printing member made of a porous material and having an outer ink-applying surface and ink supply means free of separate vents whereby a printing ink in the supply means is transferred through the porous material to the ink-applying surface by capillary action.

Parent Case Text

This application is a division of U.S. application Ser. No. 768,628, filed Oct. 18, 1968, now abandoned.

Description

BACKGROUND OF THE INVENTION

Many printing members, such as ink-applying rollers, in current use are supplied with printing ink by dipping their outer surfaces in such ink and using associated doctor blades to remove the excess ink. Other presently used ink-applying rollers are generally provided with complex ink feeding systems which often rely on positive pressure to force ink from the interior of a given roller to its outer ink-applying surface. These previously proposed printing rollers are deficient because they do not provide uniform inking, result in blobs of ink being applied upon initially starting a system, must usually be separated from their associated ink supply while not in use, and in general result in considerable waste of materials.

SUMMARY

This invention provides an inexpensive self-contained printing member or ink-applying roller which provides optimum inking performance, does not require the use of special operating procedures or components, and substantially eliminates the deficiencies of present rollers.

Other details, uses, and advantages of this invention will become apparent as the following description of the exemplary embodiments thereof presented in the accompanying drawings proceeds.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings show present exemplary embodiments of this invention, in which

FIG. 1 is a perspective view illustrating an exemplary printing member or roller of this invention in a typical application;

FIG. 2 is a cross-sectional view taken on the line 2--2 of FIG. 1;

FIG. 3 is a cross-sectional view on the line 3--3 of FIG. 2 and also illustrating the exemplary printing roller held against the outer periphery of an associated transfer roll;

FIG. 4 is a cross-sectional view similar to FIG. 2 illustrating another exemplary embodiment of a printing roller of this invention;

FIG. 5 is a cross-sectional view taken on the line 5--5 of FIG. 4;

FIG. 6 is a cross-sectional view similar to FIG. 5 and illustrating a modified version of the printing roller of FIG. 4;

FIG. 7 is a cross-sectional view similar to FIG. 2 and illustrating another exemplary embodiment of a printing roller of this invention; and

FIG. 8 is a cross-sectional view taken on the line 8--8 of FIG. 7.

DESCRIPTION OF ILLUSTRATED EMBODIMENTS

Reference is now made to FIG. 1 of the drawings, which illustrates one application of an exemplary printing member or printing roller 20 which is used to transfer a uniform layer of printing ink to a transfer roll 21 which has a comparatively soft resilient surface and the roll 21 transfers the ink to a printing cylinder 22 which is operated in a known manner to print an associated article which is to be printed. The exemplary printing roller 20 is self-contained and does not require separate components to assure that printing ink is uniformly supplied to its outer cylindrical surface.

As seen particularly in FIGS. 2 and 3 of the drawings, the printing member or roller 20 is comprised of a porous material 24 which in this example of the invention is shown as a plastic porous material which has a plurality of passage means provided in a random manner therein. The passage means in the porous material 24 are shown in the drawings by a granular representation and a few representative individual passage means or passages are designated by the reference numeral 25 and applied to corresponding individual grains of the granular showing.

The roller 20 has a central longitudinal axis 27 and an outer ink-applying surface 26 which in this example of the invention is in the form of a non-planar surface having a right circular cylindrical configuration. The roller 20 also has a pair of end closures 30 suitably fixed to opposite ends thereof and each end closure 30 has supporting shaft means or a supporting shaft 31 which is adapted to rotatably support the printing roller 20 in a known manner.

The printing roller 20 has inside ink-absorbing surface means of tubular configuration suitably formed in the porous material 24 and defined by a corresponding tubular inside surface 32 in the porous material 24. The tubular inside surface 32 of this example has a cylindrical configuration which corresponds to the configuration of the ink-applying surface 26 and the cylindrical inside surface 32 cooperates with the end closures 30 to define ink supply means in the form of an ink reservoir 33 which contains a suitable printing ink 34.

The porous material 24 is carefully selected for each application so that the effective open area defined by the passage means 25 takes into consideration the viscosity and other properties of the printing ink 34 to assure that the ink will be transferred through the porous material 24 to the ink-applying surface 26 at a precise flow rate and in a manner to be described in more detail later in this specification. Further, the printing ink 34 and porous material may also be matched to take into account the temperature range, and other environmental conditions, in which the roller 20 is expected to operate.

The roller 20 has end surfaces 35 defining opposite ends of the porous material 24 and the surfaces 35 are preferably sealed with a suitable sealing material which is impervious to fluid flow therethrough and which may be applied to the ends of the roller 20 in a thin layer designated by the reference numeral 36. The end closures or plates 30 are fixed at opposite ends of the exemplary roller 20 by suitable adhesive means and in this example of the invention an epoxy cement is used to adhesively fix each end closure 30 in position after suitably applying the layer of sealing material 36.

With the construction described above, it will be appreciated that the reservoir 33 containing printing ink 34 is free of separate vents, such as separate vents to atmosphere and as the roller 20 is rotated the ink 34 in the reservoir 33 is absorbed by the ink-absorbing surface means 32 and transferred by a wicking or capillary action at a precise flow rate from such reservoir through the porous material 24 to the ink-applying surface 26. This transfer or flow of printing ink 34 by capillarity or capillary action through the porous material 24 continues until the reservoir 33 is substantially depleted of its printing ink 34.

It has been found by tests that with the reservoir 33 free of separate vents a partial vacuum condition may exist in the reservoir 33 while the outer surface 26 of the roller 20 is subjected to normal atmospheric pressures. Under these onditions it would ordinarily be expected that the printing ink 34 would not flow out of the reservoir 33; however, it has been found that the ink 34 flows from the reservoir 33 through the passage means 25 in the porous material 24 by capillary action notwithstanding the negative pressure which may be present in the reservoir 33 and at a predictable and uniform flow rate as the ink is removed from the surface 26, and transferred on the transfer roll 21 in this exemplary application.

In this example of the invention the ink-absorbing surface 32 and the ink-applying surface 26 define the only unsealed surface areas of the porous material 24 across which ink 34 may flow and the inside ink-absorbing surface 32 is such that ink may be transferred radially through the entire cylindrical surface. However, if desired, it will be appreciated that the inside surface 32 may be sealed substantially throughout its entire surface area with only controlled portions thereof such as elongated strips, for example, remaining exposed so that printing ink 34 may be absorbed only through the controlled portions, whereby this technique of providing controlled portions enables accurate control of the amount of a given ink which may be applied by a roller 20 which uses a porous material 24 having known characteristics.

The integral reservoir 33 may be easily filled with printing ink 34 by first fixing one end closure 30 in position and then filling the reservoir 33 by pouring or flowing printing ink 34 through its open end with the roller held substantially upright and then fixing the opposite end closure 30 in position. The annular end portions 35 are preferably sealed with the layer of sealing material 36 before fixing each of the end closures 30 in position.

The roller 20 may also be filled after it is completed by providing a small opening in one of the end closures 30 leading to an associated vacuum pump so as to create a controlled vacuum within the reservoir 33 and with the roller 20 being simultaneously submerged in a supply tank of printing ink 34 which may be maintained under pressure. The pressure differential created between the printing ink in the supply tank and the reservoir 33 causes printing ink 34 to flow in a reverse direction through the porous material 24 and fill the reservoir 33, whereupon the small opening in the end closure would then be suitably sealed. It will also be appreciated that with the completed roller submerged therein the printing ink in the supply tank may be maintained under pressure without providing a separate vacuum in the reservoir 33 whereupon such reservoir would still be filled by reverse flow through the porous material 24.

Another exemplary embodiment of this invention is illustrated in FIGS. 4 and 5 of the drawings. The printing member or roller illustrated in FIGS. 4 and 5 is very similar to the roller 20; therefore, such roller will be designated generally by the reference numeral 20A and parts of the roller 20A which are very similar to corresponding parts of the roller 20 be designated by the same reference numeral as in the roller 20 also followed by the letter designation A and not described again. Only those component parts of the roller 20A which are different from corresponding parts of the roller 20 will be designated by a new reference numeral also followed by the letter designation A and described in detail.

The printing member or roller 20A has integral supply or reservoir means in the form of a plurality of reservoirs each designated by the reference numeral 40A and each being defined by an associated tubular inside surface 41A in the porous material 24A. Each elongated tubular reservoir 40A has a longitudinal axis which is arranged substantially parallel to the longitudinal axis 27A of the roller 20A and the reservoirs 40A may be arranged in a symmetrical pattern around the axis 27A while extending substantially the full length of the right circular cylindrical ink-applying surface 26A. Each tubular inside surface means 41A of each elongated reservoir 40A is in the form of an ink-absorbing surface and ink 34 in each reservoir 40A is transferred through the passage means 25A in the porous material 24A by capillary action and as previously described in detail in connection with the roller 20. The plurality of symmetrically arranged reservoirs 40A enable the provision of a more precise control of the rate of flow of printing ink 34 from the reservoirs 40A to the ink-applying surface 26A.

The roller 20A may be suitably filled with printing ink 34 by applying a sealing material 36A to one end 35A thereof then fixing an associated end closure 30A in position and filling each reservoir 40A by pouring printing ink 34 therein with the roller 20A held substantially upright. However, it will be appreciated that the roller 20A may be filled in a similar manner as described in connection with the roller 20 wherein the completed roller 20 with its ends 35A sealed with sealing material 36A and with the end closures 30A fixed in position may be submerged in a supply tank of printing ink wherein the ink in the tank is pressurized causing ink flow radially inwardly through the ink-applying surface 26A and the passages 25A in the porous material 24A to fill the reservoirs 40A.

In this example of the invention the reservoirs 40A are shown extending the full length of the roller 20A, are initially open at both ends, and utilize a pair of end plates 30A to seal opposite ends of the reservoirs 40A; however, it will be appreciated that separate plugs such as plastic or rubber plugs, for example, may be utilized to seal the opposite ends of each reservoir 40A. Similarly, it may be desired to form each reservoir 40A in the form of a blind hole, or the like, wherein one end thereof is defined by a portion of the porous material 24A and a roller 20A of this type would require a plug at only one end to thereby seal printing ink 34 within an elongated reservoir.

A modification of the roller 20A is illustrated in FIG. 6 of the drawings and is very similar to the roller 20A; therefore, the roller of FIG. 6 will also be designated by the reference numeral 20A. The roller 20A of FIG. 6 has cutout means in the form of bleeder slots 44A provided in the porous material and comprising inside surface means 41A of each elongated reservoir 40A.

In this modification the inside cylindrical surface means defining each elongated reservoir 40A may be suitably sealed with the fluid-impervious sealing material 36A which is also used to seal the ends 35A and each slot 44A is defined by a V-shaped surface 46A. Each surface 46A may define the only ink-absorbing surface through which ink may be transferred from an associated elongated reservoir 40A to the ink-applying surface 26A and by controlling the surface area defining each slot the ink flow rate is effectively controlled.

The roller 20A with slots 44A may be manufactured by any suitable technique and one technique would be to form the entire configuration of the porous material 24A, and then dip the entire roller 20A (with its outside surface means 26A masked) in the sealing material 36A whereupon the ends of the roller 20A and the inside surfaces would have the sealing material 36A applied thereagainst. The V-shaped slots 44A may then be defined utilizing a broaching tool which may have a plurality of broaching heads each defining a slot 44A with its ink-absorbing surface 46A.

The notches or slots 44A may be formed in the roller 20A so as to effectively utilize the action of centrifugal force to aid the capillary action previously described to transfer printing ink 34 from the reservoirs 40A to the outer ink-applying surface 26A. One or more slots 44A may be provided and it will be appreciated that for a rotatable roller 26A the placement of such slots determines the amount that centrifugal force will aid in the ink flow. For example, the provision of a notch 44A on a diametral line so that it interrupts the cylindrical surface 41A immediately adjacent the center 27A of the roller 20A and as shown at 50A utilizes centrifugal force a minimum amount in aiding the capillary action which is utilized to transfer ink 34 to the ink-applying surface 26A. The provision of an elongated slot 44A on a diametral line adjacent the surface 26A and as shown at 51A utilizes centrifugal force a maximum amount to aid the normal capillary action to transfer printing ink 34 to the ink-applying surface 26A. A notch 44A may also be provided at any point intermediate the locations 50A and 51A and as shown at 52A, for example, whereby centrifugal force may thus be effectively utilized any desired amount depending upon location of each slot 44A between locations 50A and 51A. In the illustration of FIG. 6 a plurality of three slots 44A are shown associating with each reservoir 40A and at locations 50A, 51A, and 52A in each instance. However, this has been done for convenience and ease of presentation and it will be appreciated that for each application the number and placement of slots 44A will vary and will be determined by test.

Thus, it is seen that bleeder slots 44A may be effectively utilized to provide a controlled flow rate of printing ink 34 to the ink-applying surface 26A wherein such flow rate may be modified after the porous material 24A for the roller 20A has been completely manufactured, thereby enabling the utilization of a given porous material with known physical characteristics with different printing inks having different physical properties merely by a simple operation of adding bleeder slots 44A. It will also be appreciated that the bleeder slots 44A may be added under conditions where the substantially cylindrical surface 41A of each reservoir has not been sealed with sealing material whereby the entire inside surface of each reservoir would define the ink-absorbing surface.

It will also be appreciated that the bleeder slots similar to bleeder slots 44A may also be formed in the porous material 24 of the roller 20. Thus, the roller 20 may also be provided with a degree of application versatility even after its reservoir 33 has been completely defined.

Another exemplary embodiment of this invention is illustrated in FIGS. 7 and 8 of the drawings. The roller illustrated in FIGS. 7 and 8 is very similar to the roller 20; therefore, such roller will be designated generally by the reference numeral 20B and parts of the roller 20B which are very similar to corresponding parts of the roller 20 will be designated by the same numeral as in roller 20 followed by the letter designation B and not described again. Only those component parts which are substantially different from corresponding parts of the roller 20 will be designated by a new numeral also followed by the letter designation B and described in detail.

The roller 20B also has a right circular cylindrical ink-applying surface 26B and inside ink-absorbing surface means shown as a cylindrical ink-absorbing surface 32B. The roller 20B has a core member 55B made of a fluid-impervious material such as metal or plastic, for example, and the reservoir means in the roller 20B comprises a plurality of reservoirs 56B shown as annular reservoirs which are axially spaced along the axis 27B.

Each reservoir 56B contains printing ink 34 and is defined by cooperating surfaces in both the porous material 24B and the core member 55B. Each reservoir 56B in this example is defined by a surface 60B in the member 55B of U-shaped cross-sectional configuration or outline and a cooperating annular surface 61B comprising a portion of the tubular surface 32B.

The reservoirs 56B may be varied as to depth, width, and spacing to provide the desired transfer of printing ink 34 to the ink-applying surface 26B essentially by capillary action and as previously described in connection with the roller 20. Further, the reservoirs 56B may be filled with printing ink 34 in any suitable manner; for example, such reservoirs may be filled by submerging the completed roller 26B in a supply tank of printing ink 34 and subjecting the printing ink in the tank to predetermined pressure to cause ink flow radially inwardly through the porous material 24B to fill each reservoir 56B.

In the detailed description of the exemplary roller 20A it was explained that centrifugal force may be utilized to aid capillary action through the porous material and provide flow of printing ink 34 to the ink-applying surface. It will be appreciated that centrifugal force may also aid in the flow of printing ink in rollers 20 and 20B.

The ink-applying surface of each roller 20, 20A, and 20B may be suitably sealed with a sealer such as a plastic coating, or a plastic sleeve, or the like, once the particular reservoir means of the given roller has been filled with printing ink 34. The sealing of the ink-applying surface protects such surface and also enables transportation and storage for extended periods of time without the likelihood of any tendency to lose the printing ink or cause hard drying of such ink within the passage means of the particular porous material. Each sealed ink-applying surface of a particular roller may be removed by a precise machining operation such as a precise grinding operation so that the passage means in the porous material are effectively opened to allow transfer of ink 34 there-across in a manner described previously.

In this disclosure of the invention the porous material 24, 24A and 24B has been described as being a plastic porous material; however, it will be appreciated that such porous material need not necessarily be a plastic material but may be any suitable porous material having passage means which enable transfer of printing ink from an associated reservoir means to the associated ink-applying surface thereof by capillary action. Further, the material selected for the porous material is preferably an inexpensive material whereby each roller of this invention may be discarded once its integral supply of ink has been depleted. However, it will be appreciated that the rollers 20, 20A and 20B may be refilled by removing an end closure 30 and 30A and flowing ink therein in the case of the rollers 20 and 20A or by reverse flow of ink through the porous material in the case of rollers 20, 20A, and 20B and as previously described.

The unique roller of this invention provides uniform inking, does not require adjustment, and provides better performance than conventional rollers. The transfer of ink 34 from the reservoir means of each roller to its outer ink-applying surface is provided by capillary action without the need for separate external vents of the type required in many printing devices in current use. Further, it has been found that the capillary action is sufficient to transfer ink 34 through the porous material under conditions where a vacuum as high as 20 inches of water and higher is present within the reservoir means of a particular roller.

The printing member of this invention is shown in FIG. 1 as a right circular cylindrical ink-applying surface and being used together with a transfer roll and a printing cylinder; however, the printing member may have any desired configuration for its ink-applying surface. For example, the printing member may have a planar ink-applying surface in the case of a stamping member.

The printing member of this invention has numerous applications and may be used in all types of marking devices, check signers, printing rollers, and the like.

Each exemplary roller presented in this specification is shown as having end plates fixed to its opposite ends and each end plate has a shaft portion extending outwardly therefrom. This type of showing has been presented for simplicity; however, it should be understood that each roller may have an elongated central shaft extending completely therethrough with end plates or closures being fastened to its opposite end portions in any known manner.

While present exemplary embodiments of this invention, and methods of practicing the same, have been illustrated and described, it will be recognized that this invention may be otherwise variously embodied and practiced within the scope of the following claims.

Claims

What is claimed is:

1. A printing member comprising, a porous plastic material having an outer ink-applying surface and having inside ink-absorbing surface means, and multiple ink supply reservoir means adapted to contain a printing ink and place said ink in contact with said inside surface means of said porous material, said supply means being free of separate vents to atmosphere, said porous material having passages therein providing capillary action and ink flow at a precise flow rate from said supply means to said ink-applying surface, said reservoir means being defined by substantially tubular surface means and further comprising fluid impervious seal means covering certain areas of said substantially tubular surface means and having unsealed area means defining said ink-absorbing inside surface means of said porous material, said unsealed area means being defined by cutout notch means in said porous material interrupting the main portion of said tubular surface means.