US2638827A - Printer platen construction - Google Patents

Description

May 19, 1953 R. P. LEAvlT-r ET A1. 2,638,827

PRINTER PLATEN CONSTRUCTION Filed July 28, 1949 ROGER P. LEAVITT WILLIAM M 7l-UTE I NVE N TORS Patented May 19, 1953 PRINTER PLATEN CONSTRUCTION Roger Phelps Leavitt and William Mansfield White, Rochester, N. Y., assignors to -Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey Application July 28, 1949, Serial No. 107,234

1 Claim. 1

The present invention relates to contact printers, and more particularly to a platen of the type shown and described 1n the applicants copending application No. 720,866, iiled January 8, 1947, now Patent No. 2,533,481, issued December 12, 1950.

This application discloses and describes a platen which consists of a curved flexible metal sheet, on the convex or under side of which is cemented an Ail-foam rubber sheet. The rear end of the platen is hingedly or pivotally connected to the printer, and, when in its elevated or inoperative position, the platen automatically assumes a curved or flexed relation. However, when the platen is lowered to its print-engaging position, it ilattens substantially into a plane, and the rubber layer is compressed to hold the print securely in position over the printing aperture. The platen itself forms no part of the present invention, and reference may be had to the above-mentioned application for information as to the structural details thereof.

It has been found, however, that with a platen of the type described, the lowering of the platen to its print-engaging position may cause the surface of the rubber layer to slip on the print and displace the latter, the disadvantages of which are apparent to those familiar with devices of this type. In order to overcome this disadvantage, the present invention proposes using a fabric covering over the curved exposed surface of the rubber pad. This covering is arranged so that as the curved platen and its rubber layer or pad attens out when moved to print-engaging position, the fabric covering which is positioned between the rubber layer and the print is maintained taut. The fabric is not secured to the rubber layer; but, on the contrary, it is laid loosely thereover so that the covering is free to slide over the rubber layer as the difference in lengths occurs when the shape changes from curved to straight. By means of this arrangement, slippage of the printing material is eliminated because the rolling action of the rubber layer is given a fabric tread on which to slip. One end of the covering is anchored, while the other is secured to a spring roller carried by the platen so that the covering is always maintained taut in all positions of the platen so that creases and/or folds in the covering are eliminated so as to insure good contact between the platen and the material to be printed, the advantages of which are apparent.

The present invention has as its principal object the provision of a tightly drawn fabric cov- 2 ering for use in connection with a curved flexible platen.

Another object of the invention is the provision of an attaching means for such a covering which eliminates the use of adhesive-securing means.

Yet another object of the invention is the provision of a covering which is mounted to permit relative movement between the platen and the covering when the platen is moved so as to prevent displacement of the print.

And another object of the invention is the pro- Vision of a covering means which is simple in construction, easily attached even to existing platens, and highly effective in use.

To these and `other ends, the invention resides in certain improvements and combinations of parts, all as will be hereinafter more fully described, the novel features being pointed out in the claim at the end of the specification.

In the drawings:

Fig. 1 is a partial side View of a photographic printer, showing the relation thereto of a curved flexible platen to which the covering of the ,present invention is applied;

Fig. 2 is a view of the platen, on a larger scale than in Fig. l, showing the relation thereto of the fabric covering of the present inventiornand the arrangement by which the covering is maintained taut in all positions of the platen;

Fig. 3 is a partial view of the platen illustrated in Fig. 2, showing the spring roller to which one end of the covering is secured for maintaining the covering taut, and the roller-supporting bracket or mount; and

Fig. 4 is a partial bottom View of the roller and mount, with the roller in sections, showing the relation of the parts.

Similar reference numerals throughout the various views indicate the same parts.

Fig. l shows a printer which comprises a housing II, the top I2 of which is provided with a printing aperture over which the negative and sensitized paper or sheet are placed to print the image of the negative onto the sheet, as is well known. The printer is provided with a platen, broadly designated by the numeral I3, which is hingedly connected at one end (left end) to the housing. This platen comprises a curved ilexible metal plate I4 on the convex or under side of which is cemented a layer of Airfoam rubber I5, or other similar compressible material. In its inoperative or raised position, Fig. 1, the platen assumes automatically a curved relation. When, however, the platen is moved to its operaccesar 3 ative or print-engaging position, it lies flat or substantially in a plane, as is deemed apparent. The platen may be moved to and from its operative position manually, or it may be moved to its operative position by a movable carriage, broadly designated by the numeral I6. When the carriage'is movedl to= the right, itv lowers. the platen against the' print, and alsoserves to compress the rubber layer I5. The structure so far described is identical to that illustrated and des scribed in the above-mentioned co-pending application and forms no part of thepre'sent invention. Details of the parts above mentioned-mavbe obtained from the above-mentioned applica.- tion.

It has been found that when the platen I3 is lowered from its curved position, shown inlig.. l, to its at print-engaging position, that the length of the exposed surface of the rubber pad It changes and this change produces a relative movement between the vpad. surface and theprint, and may tend to displace or move the latter rela.- tiveat-othe printing aperture, the--disadvantageof which isdcemed.` apparent. Inorder toovercome this disadvantage;y the present-invention provides a covering 2) which overlies, but is not secured to, thefexposed surface of the rubber padv I5. The covering, engages the p-rintwithoutmoving rela.- tive-theretofso as to maintainfpositively. the print in` its proper position over the aperture.. Also, f

and accurately in place bythe stationary fabric fr covering 26;

Inr order. tofsecure this result, the covering. 20- mustfbe free to. move relative to: the pad I5' yet` remain taut at all timesA so asv to. prevent. the. formation of creasesor Wrinkles in the fabricthel disadvantages of which are obvious. Tothis end, the fabric covering Zillis arrangedtaoverlie the rubberv pad I5, as bestshow-n iniFig. Thiscovering hasthe end.2ladjacent.the pivot.V point of the platen, anchored to the top I2.. This anchoring., may bef accomplished. in a variety ofA ways. For example,y the. leftendof the covering may, be formed withV a turned. seamv which is wrapped? aboutlZl/g turnsaroundaat.bar 2.2, the endsof.` which are secured-.tothe top. i2 by. bolts or screws 23. Thus one end, the leftend, of the covering 2li is securely` anchored to the top ofthe printer.

It.will.be apparent .from an inspectionof Fig; 2,. that. the pad. I5. andl the coveringr` 21d have aslightly different radii of curvature. Therefore, in .order to compensatey for4 the differential lengths which occur when the platen is.lowered.rneans must be provided for taking. upthe covering to. maintain. the. latter tautso as to. eliminate any possibility of wrinklegand/or foldsforming inthe covering when thel latter isdnprintfengaging relation.. Inxorder to accomplish this result, the: present invention. provides meansv for spr-ingmounting. or. tensioning the free or right-l end. of.'

the covering. 2t.. in` thepreferred. arrangement, this. tensioning.. is.. secured. by means, of a spring. roller. secured to the vfree endofv the platen. i3. A` bar, similar to Abar ZZ-,ispassed through arturnedf seam at-the rightend. of. the covering and this second, bar. can be secured. tov the roller in any suitable manner. This` spring roller ser-vesY to. draw the covering 2t tightly over the rubberl pad I5; and, when. the platenis lo.wered,.winds up on draws thecovering slightly/as the length off the pad'changes so as toinsure that the coveringis 7;,11'1 the covering when the platen islowered inE turbina thepositicn' oftiieprint.

secured by providing a. clothcovering for thenpadd smoothly and tightly drawn over the platen and in contact with the print. As the covering does not move along the top as the platen is lowered, the print does not slip but is held in proper printing position.

The spring roller construction comprised in the present embodiment, a hollow metallroller 25, the ends of. which are eounterboredvto receive pressed-in plugs 25 which support the opposite ends of a shaft 21 which extend through and projects from the opposite ends or 'the roller 25, one end: of the' roller being shown in Fig. 4. A coil spring 23 surroundsthe shaft and has one end, notshown,4 connected to the shaft While the other end, extends through an axial hole 29 formed in one of.y the'.y endv plugs and terminates in a radial bent end 3o. which extends through a registering radial' hole in the' plug 2t, al1 as clearly illustratedl in Fig. 4. The ends of shaft 2l are supported in end plates 3| secured to or formed from a:A curved portion. 'd2 of a supporting plateor bracket. $3. secured-to the endsofl the-metal. plate I4, as .best-shown inFig. 3.

In order to retain the covering 2 il. inl a taut rela.-

tion, the spring Z8: is wound up or tensioned. To1

secure this result, the shaft 27 and roller arel r0- tatedrelatively to wind. up. thespring. 28. in a- Well known manner. When the spring has been prop against rotation. Thus, spring 2B`ismaintained under tension andy tendst'o turn the roller. to wind up or draw the covering, 2d' tightlyl across. the surface of the rubber p-adl Iii of the' covering decreases.

rubber' pad. This covering does not'v move relative to the print so that the latter is retainedlin proper position. fabric tread on which the rubber pad may roll'or slip WithoutY disturbing the position of theiprint.v

By'springemcuntingihe covering, adhesive means are eliminated; thus. preventing creases orv folds from forming in the covering solas tofinsure goed Contact',` the advantagesof which are deemed apparent. The elimination of folds or creases iii-the covering materially increases the life of'the covering.

The covering 2!" should be of' a composition. Whichrallows free slippageV of. the rubber pad on the covering as the platen is moved so as to enwithstandr` continued usage. that Nylon Neoprene cloth meets these specii'ca.-

tions: Tlre'designation of'such a material isnot, however, intended as' a limitation but merely. as.

an illustration" of one" suitable 'form' of material.

C: OtherI materials which meet. the specifications mavobviously be used.

Thepresent :invention thus provides a flexible curved platen" structure which may be moved.`

to its dat' print-engaging position without disoi the platen and'thisccveringis. heldin posi;-

tion without the use oi" adhesives-thuseliminating any possibleformationlof creases-onWrink-les As the. platen is. lowered, and assumes a l'at position,- the. length I Such decreasefcauses. the'. roller to function towind up the coveringand4 maintainY the. latter in a taut relation over thev Also, thev covering provides a4 This result..

the print-engaging position, thus insuring good Contact between the negative and the sensitized print. The taut covering arrangement may be applied to existing machines Without material alteration thereof. 'Ihe slippable covering is simple, easy to apply and highly eiective in use.

While one embodiment of the invention has been disclosed, it is to be understood that the inventive idea may be carried out in a number of ways. This application is, therefore, not to be limited to the precise details disclosed, but is intended to cover all variations and modifications Which fall Within the scope of the appended claim.

We claim:

In a photographic printing apparatus having a top formed with a printing aperture, the combination With a flexible platen which is hinged at one end to said top and which assumes a curved relation when in its inoperative position and is movable substantially into a plane when in its operative position to hold a sensitive sheet over said aperture, said platen having a layer of compressible material secured to the under surface thereof, the exposed face of said material decreasing in size as the platen is moved from its inoperative to its operative position, of a fabric covering arranged in overlying relation and in positive contact with the full area of said face in both positions of said platen, means for anchoring one end of said covering adjacent said one end of said platen, and spring means carried by the other end of said platen and connected to the other end of said covering to maintain the covering in a taut relation over and in positive contact with said face in both positions of said platen, the movement of said platen to its operative position causing said layer to move relatively over said covering as said face decreased in size, and said spring means taking up any slack in said covering as said platen is moved to its operative position to provide a smooth member which engages said sheet Without slipping relative thereto.

ROGER PHELPS LEAVITT WILLIAM MAN SFIELD WHITE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,093,509 Weidner Apr. 14, 1914 1,144,014 Westman June 22, 1915 2,155,149 Rutherford Apr. 18, 1939 2,364,580 Young Dec. 5, 1944 2,421,150 Jacobson May 27, 1947 FOREIGN PATENTS Number Country Date 194,524 Great Britain Mar. 15, 1923

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