US3521562A - Platen roller printing machines with printing plate support means - Google Patents

Description

w. P. BARBOUR v 3,5 PLATEN ROLLER PRINTING MACHINES WITH PRINTING PLATE SUPPORT MEANS Filed'Jan. 24. 1967 Jul 21, 1910 WILLIAM PLUMB BARBOUR 3,521,562 PLATEN ROLLER PRINTING MACHINES WITH PRINTING PLATE SUPPORT MEANS William P. Barbour, Alexandria, Va., assignor to Farrington Business Machines Corporation, Springfield, Va.,

a corporation of Massachusetts Filed Jan. 24, 1967, Ser. No. 611,331 Int. Cl. B4113 1/54, 3/54 US. Cl. 101-269 2 Claims ABSTRACT OF THE DISCLOSURE An apparatus and a method of shimming a printing plate support in a printing machine by utilizing a deformable material in the shimming process to level the printing plate support, the deformable material being displaced through a printing cycle, and then hardening the material in its displaced state to provide optimum print quality for subsequent printing operations on the machine.

The present invention relates to a printing machine, and more particularly, to an improved printing machine and method of producing the same for recording data on form documents and the like by means of plate-like printing devices having raised type characters thereon. In printing machines of the variety described above, it is well known in the art that in order to obtain a uniform and clear print, the printing pressure should be maintained as much near a fixed value as possible. In imprinters of the type Where the shaft or other means carrying the platen is constrained to reciprocating movement within a predetermined path, the lower portion of which platen defines a plane over the bed area, a reference gap will exist between the aforementioned plane and the bed surface. Such a gap can be set toaccommodate a printing plate and document of pre-evalua'ted fixed thickness to provide optimum printing pressures. However, when dimension tolerances of each printing machine vary, such a manner of handling the gap is not practical. The problem of the variance of tolerance dimensions with each machine has been solved by utilizing a separate printing plate support anvil of a definite thickness on the bed and varying the height by which the anvilis spaced from the bed by placing a value of fixed thickness metal shims between the bed and support anvil, which is necessary to arrive at the proper reference gap for accommodating each individual printer, the reference gap now being defined by the distance between the support anvil upper surface and the platen. Such an approach to the problem has worked well; however, two significant drawbacks of this approach are: the large amount of time it takes in the trial and error process of selecting the right value of shimming for each individual printer, and the necessity for maintaining a plentiful supply of metal shims of varying thicknesses. I v 1 The general purpose of this invention is to obviate the drawbacks encountered above in the manufacture of printing machines and at the same time to provide a finished product which provides for improved print United States Patent be placed between the support anvil and the bed, and upon the support anvil would be seated a gauge plate having a thickness slightly less than the combined thickness of the conventional printing plate and document to be employed with the printing machine for printing purposes. Then, the printing head would be actuated to traverse the bed and introduce a printing pressure to the gauge plate causing the uncured thermosetting resin beneath to be displaced by said pressure to a level providing for optimum print quality since the displacement adjusts the support anvil surface to lie in a plane parallel to the plane tra' versed by the platen during the printing process. Such an accomplishment is achieved in but merely one step comprising a single pass by the print head. Thereafter, the thermosetting resin is allowed to cure or harden at its displaced level for subsequent printing operations.

Other objects, advantages and capabilities of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating a preferred embodiment of the invention.

In the drawings:

FIG. 1 is an exploded perspective view showing one type of a method and apparatus that could be used in accordanace with the present invention for providing shimming material in adjusting a printing machine.

FIG. 2 is bottom plan view of a printing plate support anvil used in the present invention with shimming material placed thereon.

FIG. 3 illustrates a side elevation of one form of a printing machine disclosing how the present invention is employed.

FIG. 4 shows a partial enlarged section of the printing machine taken on the line 44 of FIG. 3, while the printing head overlies the support anvil.

'FIG. 5 is an enlarged partial side elevation of a simulation strip 31 shown in FIG. 3.

With reference to the drawings, in FIG. 1 there is shown a method of preparing the shimming material employed in the present invention. The type of material utilized should have deformable, self-hardening characteristics, that is, the material, preferably a thermosetting resin, should be deformable at one stage of the shimming technique and harden itself at a second stage. One kind of such material found to perform well is Epoxybond Adhesive Putty, a product of The Electric Storage Battery Company. This epoxy consists of two compounds, a resin and a hardener, each being of a dough like consistency.

Epoxy resins of the type noted above are basically thermosetting resins which can be reacted with curing agents or catalysts. General properties of epoxy resins comprise their excellent adhesion to a great number of materials,

of one hundred, which value is virtually the maximum quality. To attain this, the present invention contemplates amount of pressure applied in imprinting machines of the type described herein. The Epoxybond, when hardened, can also be safely used at temperatures up to 200 F. and is not affected by moisture. Such characteristics are quite desirable as imprinting machines are subject to a wide variety of climate conditions.

Referring back to FIG. 1, there is shown a flat metal plate 11 having a plane surface covered by a release agent comprising a wax coating, which for illustration purposes is depicted in the form of a wax paper sheet 12.

Adjacent each one of two opposite sides of the metal plate 11 and overlying the wax paper sheet 12, are a pair of elongated gauge pieces 13 and 14 each selected to have the same uniform thickness dimension T, which dimension is evaluated to be greater by a specified amount than the average shim thickness, the manner of evaluating the same to be described in detail hereinafter.

The thermosetting resin will first be mixed with a curing agent or catalyst (hardener) which will provide a suitable period for the workable life (pot life) of the activated resin compound, such as for example thirty minutes, allowing sufficient time to use the mix for manufacturing purposes. In the preferred embodiment, two compounds are selected having a dough like consistency and are mixed by a kneading process to form a rope 15, as shown in FIG. 1, having a diameter considerably greater than the dimension T previously made mention to. Resin rope 15 is then placed upon wax paper sheet 12 to lie approximately midway of the two gauge pieces 13 and 14. A second wax paper sheet 16 is then placed over the resin rope, and a roller 17, arranged to simultaneously overlie both gauge pieces 13, 14, is acted upon with a pressure rolling action to flatten out the resin rope into a rectangular like sheet 18 characterized by a uniform thickness dimension T. The rectangular like resin sheet 18 is then cut into a plurality of resin strips 19 each having a sufficient length to accommodate the width of a printing plate support anvil or like device such as a dealer or station anvil, with which resin strips 19 are to be employed. It is to be noted that although resin strips 19 are shown to be rectangular in form, most any suitable shape might be used.

The particular printing machine depicted in FIG. 3 is one of many types with which the present invention might be employed, wherein an imprinter base 21 is designed to have end bars 22 and 23. Adjacent end bar 22 is a printing head 24 positioned at the start of an imprint cycle, the printing head comprising a roller platen 25 rotatably mounted on a shaft 26. The printing head is adapted to traverse a bed 27 defining the top of the base by way of roller bearings 28 which are guided by and restricted to reciprocating motion by Way of a pair of parallel paths 29 formed at each side of base 21.

In an imprinting machine of the type shown, due to its design the diameter of roller bearings 28 is slightly less in measurement than the height of each paths 29 which it traverses; however during printing the force of the printing plate acting upwardly on roller platen would act on the entire printing head to urge it upwardly and force roller bearings 28 against the upper surface of paths 29. In order to simulate the action of roller bearings 28 during an imprinting cycle, simulation strips 31 are temporarily placed at the bottom of each of paths 29. From FIG. it may be observed that simulation strips are comprised of a pair of elongated bands 30 which are separated toward the middle thereof, below the printing area on the bed, by a hard rubber pad 30 which causes upward movement of the roller bearings into contact with the upper surface of paths 29.

Prior to applying the plate supporting anvil to a printing machine, the machine should otherwise be completely assembled, and the printing head 24 should be positioned in its start or initial position of an imprint cycle. Resin strips 19 are then placed at the underside of a printing plate support anvil 32 in the manner shown in FIG. 2, for providing subsequent support about the center and at two opposite ends situated at the underside of support anvil 32. Thereafter, the support anvil'is placed in its proper location on bed 27 of the printing machine as illustrated in FIG. 3. Seated upon the support anvil is a gauge plate 33 which is of a thickness slightly less than the combined thickness of a printing plate and document to be employed with the printing machine. I

In explanation of how the thickness of gauge plate 33 and the initial thickness of resin strips 19 are arrived at, attention is directed to FIG. 4 wherein an imprint cycle is in progress and roller platen 25 overlies gauge plate 33. The dimension R refers to the distance from the lower 4 tangent of platen roller 25 to the bed surface 27. The distance R comprises the following thicknesses:

(a) The thickness of a document to be employed for printing purposes.

(b) The thickness of a printing plate (inclusive of embossing) to be employed for printing purposes.

(c) The thickness of anvil 32.

(d) The thickness amounting to the average shim value, and

(e) The thickness accounting for the necessary negative value to provide an interference between the printing plate and lower tangent of platen roller 25 for introducing a printing pressure to transfer an impression upon the document, which value we shall arbitrarily designate as X.

Since the thickness values of (a), (b), (c), and (e) are known, the thickness value (d) may be readily arrived at by subtracting the combined thickness value of (a), (b), (c), and (e) from the value R. However, the value R and therefore (d) is not the same for each machine due to manufacturing tolerances, therefore a value of (d) cannot be readily arrived at. Thus the selection of the proper value of fixed thickness metal shim or shims will vary from machine to machine, as heretofore noted, and will involve a time consuming trial and error process to properly elevate or adjust the plate supporting anvil for providing good print quality.

In the present invention, the maximum tolerance that might be encountered in any one printing machine is first evaluated and then determined to be the thickness which the resin strips 19 (shims) shall initially be set for. In order to achieve the latter, it is quite evident that gauge pieces 13 and 14 shown in FIG. 1, must be of this maximum tolerance value, previously referred to as T, so resin rope 15 can be flattened into a resin sheet 18 and cut into resin strips 19 having a thickness T which is greater than the average shim value.

Gauge plate 33 is merely a tool by which each printing machine is to be adjusted and has a thickness which is equal to the combined value of (a) and (b) less (e) noted above, or the combined thickness of a printing plate and (including embossing) a document, less an amount of an inerference value X arrived at by conventional testing procedures. If desired, a magnetized gauge plate might be employed to provide a simple but quick and. secure method of temporarily attaching the gauge plate to the support anvil which is normally made of steel.

After all the above noted steps have been carried out, the assembly operator will manipulate printing head 24 to drive it across bed 27 in an imprinting cycle, and due to simulation strips 31 the pressure of roller platen 25 on gauge plate 33 as shown in FIG. 4, will be the same as that encountered during a normal printing cycle and will displace the deformable compound, ofwhich resin strips 19 are comprised, to a level so that the surface of gauge plate 33 as well as the surface of the support anvil, each lies in a plane parallel to the plane defined by the lower tangent of the roller platen 25 while in printing pressure engagement therewith.

Accordingly, the composition defining resin strip 19 is displaced on a two dimensional basis in direct correspondence with the tolerance variance associated with the particular printing machine being adjusted. The gauge plate 33 and simulation strips 31 are then removed for use with another printing machine and the present precisely shimmed printing machine is set aside allowing the compound to cure so resin strips 19 will be hardened in their displaced state. For the particular thermosetting resin previously referred to, a curing period of approximately twelve hours should be sufficient.

It can be seen that this leveling or shimming operation upon plate supporting anvil 32 'is accomplished in merely but a single stroke involving a single print cycle operation, whereby an individual printing machine is accurate 1y adjusted to provide optimum printing pressure for producing acceptable print quality with documents and printing plates having a combined thickness substantially the same as that for which the printing machine has been set-up.

Since an epoxy type resin could be utilized in the present invention, its adhesive property may, if desired, be advantageously employed to firmly bond the plate supporting anvil to the bed, once the thermosetting resin has hardened. However, sometimes it may be desirable to remove the plate supporting anvils at a later date for any one of a variety of reasons, such as further shimming where a new standard printing plate or document having a significant thickness difference from the old one, is to be used in the printing machine. In such instances, prior to placing resin strips 19 in the printing machine a release agent such as a wax or silicone might be applied to the bed and the underside of the plate supporting anvil to prevent adhesion to resin strips 19. In such instances, for securing the plate supporting anvil to the bed and the shimming material therebetween, a pair of partially threaded studs (see FIGS. 2 and 4) intergrally fused with anvil 32 are provided, and the bed would be adapted by way of a pair of openings 20 for receiving the studs 20 therethrough to the underside thereof, where the studs could be fastened to base 21 by lock nuts 34.

It should be noted that not all thermosetting resins might be suitable for use in the instant invention, in that several important characteristics of the shimming material should be present for good operating performance of the material under a variety of climate and other environmental conditions. Some of the more significant thermosetting resin characteristics which should be present comprise: a compressive strength of greater than 100 p.s.i., a negligible coeflicient of expansion, and being virtually impervious to moisture. The value of 100 p.s.i. was selected since most all printing machines of the type noted herein require printing pressure of less than 100 p.s.i. for good quality print transfers.

Hence, while a preferred embodiment of the invention has been described and illustrated, and selected modifications and variations have been referred to, it is to be understood that the present embodiment is capable of further modifications and variations.

I claim:

1. A printing machine for printing indicia on a document, comprising at least four members,

a first one of said members forming a bed for said machine,

a second one of said members defining means for supporting a printing plate having raised characters,

a third one of said members being a platen mounted to move in a path parallel to and substantially contiguous with the raised characters of said plate for progressively pressing successive portions of a sales slip interposed between said second and third members, against said plate,

a fourth one of said members comprising shimming means fixedly interposed between and bonded to said first and second members to provide for an optimum print quality transfer,

said shimming means comprising a cured thermosetting resin material having a compressive strength greater than the printing pressure employed in said printing machine, a small coefficient of expansion, and substantially impervious to moisture.

2. A printing machine for printing indicia on a document, comprising at least four members,

a first one of said members forming a bed for said machine a second one of said members defining means for supporting a printing plate having raised characters,

a third one of said members being a platen mounted to move in a path parallel to and substantially contiguous with the raised characters of said plate for progressively pressing successive portions of a sales slip interposed between said second and third members, against said plate,

a fourth one of said members comprising shimming means fixedly interposed between said first and second members to provide for an optimum print quality transfer,

said shimming means comprising a cured thermosetting resin material having a compressive strength greater than the printing pressure employed in said printing machine, a small coefficient of expansion, and substantially impervious to moisture,

aperture means provided in said first member,

stud means secured to said second member and extending downwardly through the aperture means, and

mechanical means for securing said stud means to said first member.

References Cited UNITED STATES PATENTS 2,068,707 1/ 1937 Reardon 101269 2,581,718 1/1952 Schafi'ert et a1 101401.1

3,213,789 10/1965 McIlvaney et a1. 101401.3

3,277,822 10/1966 Maul 101-269 3,363,550 1/1968 Kruger 10l269 5O WILLIAM B. PENN, Primary Examiner U.S. Cl. X.R.

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