US2534784A - Photomechanical printing frame - Google Patents

Description

Dec. 19, 1950 J. D. MAXWELL 2,534,784

PHOTOMECHANICAL PRINTING FRAME Filed Jan. 11, 1949- -4-Sheets-Sheet 1 INVENTOR. JOHN D. MAXWELL H TTORNE Y5.

4. Sheets-Sheet 2 L 3 0N" W m WM m D m. J W

J. D. MAXWELL PHOTOMECHANICAL PRINTING FRAME Dec. 19, 1950 F1194 Jan. 11, 1949 Dec. 19, 1950 J. D- MAXWQLL: PHQTOMECHANICAL PRINTING FRAME 4 Sheets-Sheet 3 Filed Jan. 1.1;, 1949 INVENTOR. JOHN D. Mnxwaz.

BY W, ATTORNEYS- MEXE 02 G Dec. 19, 1950 J. DVMAXWELL PHOTOMECHANICAL PRINTING FRAME 4 Sheets-Sheet 4 Filed Jan. 11, 1949 INVENTOR. JOHN D. MAXWELL I FM 14 TT ORNEYa Patented Dec. 19, 1950 UNITED PHOTOMECHANICAL PRINTING FRAME John Maxwell, Glen Head,-N. Y., assignor to Powers Photo Engraving Company, Glen Cove, N. Y., a corporation of ew York Application January 11, 1949, Serial No. 70,212

' GClaims. (ates-'13)" The present invention relates to a novel and improved photomechanicalprinting frame particularly for use in preparing large printing plates. I

Objects and-advantages of the invention will be set forth in part hereinafter and in part will be obvious herefrom, or may be learned by practice with the invention, the same being realized and attained by means-of the instrumentalities and combinations pointed out'in the appended claims; 7 s :o

The invention consists in the novel parts, constructions, arrangements, combinations and im provements herein shown and described.

The accompanying drawingsreferred to herein and constituting a part hereof, illustrate one embodiment of the invention, and together with the'descriptiom serve'to explain the principles of the invention. r -Of-the drawings: 7

Figure 1 is a general perspective view of a printing frame illustrative of the present inven tiony" Figure 2 is a vertical sectional view, with parts omitted and others broken away and showing, in full lines, the printing frame in closed posifragmentary detail in broken lines, showing the,

frame in inspection position;

'3135. the wholearea of the printing frame so that at a :distance "of a few inches from the bank ofthe hinged blanket frame is to be raised for; loading orunloading, and positive guiding means; areeprovided for preventing movement of the frame towards the lamp bank while it is being,

7 Figure 4 is a similar schematic view showing,

in broken lines, the printing frame as it is moved to exposure position, and in full lines, the printing frame in exposure position.

Thepresent invention has for its object the provision of a novel and improved phot0mechan' ical printing frame particularly adapted for use'in making largerotogravure and offset print ing plates. A further object is the provision of a printing frame which may be'easily loaded, turned for inspection and thereafter moved to exposure position, and which is relatively compact. 'Still another object i the'provision of an improved printing frame which is balanced and requires little effort to move it to its several positions, and which has power means for lifting one of the frame members when the frame is to be loaded orunloaded.

In accordance with the preferred and illustrative embodiment of the invention, the light source is a bank of closely adjacent tubular lamps, such as fluorescent lamps, extending over lamps theillumination provided is substantially uniform. The bank of tubular lamps are preferably parallel to each other and the sockets are mounted at the ends of the vertical lamps in an upright housing. 'The printing frame proper comprises a pair of frames hinged to each other along a long edge, one frame being the glass carrying frame, while the other frame is the.

'blanketccarrying frame, which frames can be.

brought together and clamped in light pressure contact ,with each other to press a sensitized member (such as carbon tissue or an ofiset plate) into contact with a positive'transparency or neg ative to be printed. The printing frame is usually a vacuum frame as otherwise it is dimoult to ob tain good contact over the whole area when extremely large work is to be handled, such as aufull sheet which maybe as large as 52" x 72". Atya central, point of each side edge of the to .the bank of lamps.

Locking means are provided for'firmly holding. the frame in a horizontal position, as when rotated from loading to inspection position, and permitting swinging movement of the frame from. inspection-position towards the lamp bank, 7 and swinging movement of the frame fromeex-r posureposition to unloadingposition.

vPower .means provide for raising the large heavy blanket frame when the apparatus. is to be;,

loaded. orunloaded and for holding the blanket frame in raised position, and means are also provided for engaging the power means with the preferred embodiment of the invention: 1

The lightsource comprises a large number of parallel vertical fluorescent light tubes I9, closely spaced together and arranged in a plane to provide a bank of lamps, the tubes being so closely spacedthat at a few inches distance from the lights they produce a uniform: intensity of light.

' tire printing frame.

Each of the lamps is longer than the height of the printing frame and the bank of lamps is wider than the width of the frame so that uniform light intensity may be had over the en- Lamps ID are close to a corrugated or diffuse reflecting surface ll supported parallel to them and are provided with suitable sockets [2 at their ends and these sockets and the necessary starters, ballasts and wiring are mounted within the upright casing H which forms a support for the various parts of the apparatus.

The printing frame proper comprises a pair of sturdy rectangular frames It and 18 of the same general size which are hinged together along one of their longer adjacent edges by means of hinges 25. Frame It is the glass frame and is provided with a single sheet of heavy transparent glass securely held in the frame, while frame 18 is provided with a vacuum blanket, the glass and blanket being so relatively positioned that they contact with each other when the frames are in closed or printing position.

Locking means are provided for securing the frames 16 and i8 together. As embodied, a shaft 22 i journaled in the frame 18 and extends from one side edge of the frame to the other. At either end, shaft 22 is secured to a latch member 24 having a hook portion 26 to engage with a pin 28 carried by the glass frame. Each latch member 24 is connected to a bar 29 which extends parallel to the frame l8 and is supported at its forward end by means of a short link 30 pivoted on the frame l8. One latch'24 is conveniently, provided with a handle 32 at the point where it is pivoted to the bar 29.

Means are provided for pivotally and slidably supporting the frames l6, l8 and for this purpose rollers 34 are rotatably mounted, one at either end of the glass frame [6, the-two rollers 34 preferably being axially alined, and each securely mounted on a stud 36 projecting from a plate 38 welded to an end of the frame l6 so that the rollers are located substantially symmetrically with respect to the mass of the frames l6 and I8 thereby allowing the frame to be substantially balanced and to be moved easily from one position to another.

Horizontally extending trackways are provided for the rollers 34 and comprise the upper and lower rails 40 firmly mounted on the side members 42 of the apparatus and extending parallel to each other and perpendicular to the lamp bank at more or lessthe center of its height. One such pair of rails 40 is provided at each end of the frame and the rails are long enough so that the frames l6 and I8 may be swung without hitting the bank of lamps or may be moved close to the bank, always about the stud 3.6 as a center of rotational movement.

For controlling the rotational movement and the sliding motion of the frames [6 and I8, frame I6 is provided with small rollers 44 near each of its corners, mounted on studs parallel to studs 36 and rollers 44 cooperate with circular track members mounted on the side members 42. Tracks 46 each comprise angle strips secured to their respective side members 42 and curved to form an are centered on the stud 36 in its rearmost position as shown in Figure 3 so as to hold the frames with the roller 44 engaging the concave surface of the track 46.

A short arcuate track 48 is formed at the for: ward ends of tracks 40 so as to be engaged on tion of the frames about stud 36 in the position shown in Figure 3 the rollers 44 (at the ends of frame l6) are controlled or engaged part of the time by track 46 and part of the time by track 48.

Similar tracks 46 and 48 are provided at the other end of the frame which are mirror duplicates of those shown, and are mounted on the inner side of the other side member 42.

A third track 50 comprises an upper curved section 5|, also centered on the same center as track 46, but merging into a lower straight and slightly inclinedportion 52, the inclination being such as to accommodate the offset of roller 34 and 44 as the frames l 6 and [8 are moved to vertical position, asshown in full lines in Figure 4.

To control the sliding or swinging movement of the frames l6, [8, a guide strip 54 is mounted so as to be normally almost parallel to the track 52 and anchored at its lower end only to the side member 42, leaving the upper straight portion as a flexible switch permitting clockwise movement only of the frames l6, l8. Normally the upper end of track 54 engages track member 48, as shown in Figures 2 and 4, andmay be displaced by either roller 44 as shown in Figure 3,, as the frames are swung in a counterclockwise direction. However, as the frames are swung in a clockwise direction, the track 54 forces sliding movement of the frames so that the frames are movedglassside towards the lamp bank and into a vertical.

position for exposure. V

Locking means are provided for holding the frames in a horizontal position, either side up, and comprise the pivoted latch members 60, engageable with rollers 44, and pivoted by rod 62 and may be swung by arm 63 which is actuated by is lowered, clamped by latches 24 and thenrotated in a counterclockwise direction to the Positions.

shown in Figure 3 and latched in horizontal posis tion for inspection. Latches 50 arethen released and the frames are rotated clockwise'causing the rollers 44 to move downwardly between tracks 54 and 52 and causing the frames I5, I!) to swing,

forward as shown in Figure 4 tothe full line posi-., tion shown which the exposure, position.

After the exposure has been completed, the

frames are rotated from a vertical position to a horizontal position where they are held by;

latches 60 by counterclockwise rotation of the frames, positioning the blanket frame I8 uppermostso that it may be lifted to, remove the exposed sensitized plate or material and negative or transparency Suitable switching and timing means are provided for starting the exposure and controlling the length of exposure preferablylallowing lights it to be energized only whenfthe frames are in exposure position and automatically start? ing the exposure when the frames l6 and I 8 are, Th m a may be of conventional construction and are not moved to their vertical'position.

shown.

The backing blanket in the frame It is .preferably a vacuumblanket and is connected to suitable vacuum pump (not shown) by means of flexible tubing l0 connectedv to the blanket and.

their convex side byroller 44. In the simple IOW- 76 to a rigid tube not shown but carried by frame Hi and which communicates with-a gland coaxial with'o'ne. of the studs 36 which is .drilledto provide a vacuum passageway and thence to 2. flexible tube (not shown) which is connected to a control valve in one of the side members 42, controlled by valve lever 12, so that, with the frames in adjacent position, vacuum may be established between them to press the sensitized material into close contact with the transparency supported against the glass of frame I6.

For raising and lowering the heavy frame IB from closed to open position, while the frames .16 and i8 are in loading or horizontal position with the blanket frame l8 uppermost,-power means are provided which are preferably engageable with the frame as the frame locking latch 24 is moved to unlocking position. As embodied, each pivoted link is formed with a hook portion Hi engageable with a pin 16 extending laterally from a long pivoted arm 18, pivoted on the main part of the machine. Arms 18 are parallel to each other and closely adjacent the side edges of the frame I8 and normally rest in a horizontal position. Each arm 18 is connected to its chain 80 which passes overan idler sprocket '82 and a driven sprocket 84 mounted above the bank of lamps l0 and is connected at its other end to a small weight 86. Sprockets 84 are fast on shaft 88 and driven by self-locking worm gearing from motor 90 under control of a manual switch 92 for driving the motor 90 in either direction.

With the frames I6, I8 in the position shown in Figures 1 and 2, unlatching of frame l8, by movement of the latches 24 causes the frame l8 to be engaged with the motor actuated lifting bars 18 through hooks l4 and pins 16 so that thereafter the frame l8 may be raised or lowered under control of the motor switch 92.

A complete cycle of operation of the embodied form of the invention may be summarized as follows.

In loading position, with the blanket frame l8 up and glass frame l6 horizontal, and latch 60 moved to unlocked position, manual switch 92 is moved to frame raising position; motor 90 is energized, causing chainBO to be lifted, moving bar 18 upwardly about its pivot and raising blanket frame I8 through latch 30. When the glass frame [8 has been sufficiently raised, switch 92 is moved to its open, central position stopping motor 9% in its raised frame position. When the negative or transparency and sensitized material have been properly positioned, switch 92 is reversed to lower the frame l8.; Then, handle 32 is pulled to lock frames l6 and I8 together through latch 24 and to simultaneously release latch 30. Vacuum valve 12 is then opened to apply suction to the blanket and when vacuum has been established, lock 60 is released and the frames [6 and I8 may be rotated counterclockwise 180 to bring the glass frame [6 uppermost for inspection of the work. In this position, the frames are again locked by lock 60. If the work appears satisfactory, the frames are unlocked from lock 60 and may then be revolved clockwise 90 to position the glass frame is vertically and adjacent the lamp'bank for exposure.

When the exposure has been completed, the timer has shut off the lamp bank, and the frames may be rotated counterclockwise to bring the glass frame it uppermost and locked in horizontal position by lock 60. If the sensitized material looks satisfactory, the frames are unlocked and may be rotated 180 in a clockwise direction.

If underexposed, the frame may be moved in clockwise direction to exposure position. When the blanket frame 18 is in upper posi-' tion, the vacuum is released and the blanket bled to atmosphere through valve 12. The frames are then unlatched by movement of latch 24, simultaneously connecting the blanket frame l-8 to bar 18 and motor 90. When the blanket frame has been raised under control of switch 92, the frame maybe unloaded. The invention in its broader aspects is not limited to the specific mechanisms shown and described but departures may be made therefrom within the scope of the accompanying claims r without departing from the principles of the invention and without sacrificing its chief advantages.

What is claimed is:

1. In a photomechanical printer wherein a series of tubular light sources are vertically aligned and a printing frame is provided for carrying a sensitized material and an image to be repro-' duced by exposure to said light sources, means for moving saidprinting frame from a horizon tal loading position to an inverted horizontal inspection position and for moving said printing frame from a horizontal position to'a vertical exposure position closely adjacent said light sources, comprising a pair of horizontaltracks, one at each side of said frame, said tracks extending from a point adjacent said light sources for a distance substantially one-half the length of said frame, a pair of pivotal supports, one projecting from the substantial center of each side of said frame, said supports being an axis of rotation for inverting said frame and said supports acting in conjunction with said tracks to forma transporting means for moving said frame to and from a proper vertical photomechanical printing position adjacent said light sources.

2. Apparatus [according to claim 1 in which auxiliary track means cooperating with the ends of the frame are provided for controlling the direction of pivotal and sliding movements of the frame.

3. Apparatus according to claim 2 in which said auxiliary track means includes a pair of tracks, one at each side of said frame, concentric with the :axis of said supports when the frame is in a. horizontal position for rotating and inverting said frame, a pair of tracks tangential to said concentric tracks for positioning said frame adjacent said light sources, and means for selecting the operative pair of tracks.

4. Apparatus according to claim 1 in which means are provided cooperating with the frame for releasably locking the frame in either horizontal position.

5. In a photomechanical printer wherein a series of tubular light sources are vertically aligned and a printing frame is provided for carrying a sensitized material and an image to be reproduced by exposure to said light sources, means for moving said printing frame from a horizontal loading position to an inverted horizontal inspection position and for moving said printing frame from a horizontal position to a vertical exposure position adjacent said light sources, comprising a pair of supports, one projecting from substantially the center of each side of said frame, a pair of horizontal tracks, one at each side of said frame for carrying said supports, said horizontal tracks extending outwardly from a point adjacent said light source foria dis- :endaofsaid frame, tone of :each :pa'ir at each side zflffSflidiTl'filIlB, .a pair'ofiarcuateguide tracks, one

:ateach side of said frame adapted to receive one pair of :said supporting guides to "define an :arc

:ofm'tation for inversion 01 :said frame, ia pair of generally vertical guide tracks, one at each :side ofsa'id :frame closely adjacent said light sources, said vertical tracks being adapted 2t0 receive said supportingsguides and to define arpath for bringins said :frame .into exposure position :in close .pamallelzproper printing proximity with said light sources, :and means for "selecting the operative guide tracks, said supports being horizontally movable to :permit translator-y Lznoveinent of :said frame when said vertical guide tracks are operative and being stationary when-said arcu'ategguide tracks are operative.

16.111 =2. :photomechanical printer wherein o. series of tubular light sources are vertically aligned and a :heavy printing frame, including a glass frame and blanket frame, is provided for carrying asensitized material and an image to be reproduced by exposure to light sources, means for moving said printing frame from a horizontal loading position with said blanket frame above said frame to inverted horizontal. inspection position i-ior .moving said printing l ra-me from .a horizontal position to a vertical exposure position :adjacent said light sources, -.con' prisin-g a pair of supports, one projeetingi-rom substantially the centeref each side of :said glass frame, a {pair of horizontal tracks, one at each side of said .f-rame for carrying said supports, said horizontal tracks extending .outwardly from o point adjacent said light sources for (a distance substantially one-shelf the ll'ength of :said rfreme, so pair of arcuate rguide tracks,

at :each side of said rirame "adapted ftO receive said supporting Jguides to :tde'fine .an arc of rotation *for inversion of said Iframe, :a :pair :of .igen'erally vertical guide tracks, one at each end of said ifralme closely adjacent :said :light sources, :said *vertical guides :being adapted "to receive said supporting guides and defines. 'pa'thlfor bringing. said ire-me into exposure position I-in close parallel proper printing .zproxirnity \WithiSaid liglit sourc'es, means for selecting the "operative :guide tracks and power Lmean's tier opening :said .blanket iframe from said glass "frame during loading, said supports being horizontally movable to permit tr-anslatoryimovement (of said .frame when said vertical guide tracks Yareoperative and being station ary when :said arcuate guide tracks are operative.

:JOHN D. MAXWELL.

REFERENCES CITED The following references are 'of record in the file of this "patent:

UNITED STATES PATENTS Number Name Date 1,505,818 sweigard Aug. 19, 1924 1,583,446 Cross May 4, I926 12,169,271 Michael s Aug. 15', 1939 2,170,622 :Sussin Aug. '22, 1939 2,189,233 Vander-veld Feb. 6, 1940 ali-90,49 Campbell .Dec. 11, 1 945 FOREIGN PATENTS Number Country Date 8.75.;031 Erance June 1, 19.42 564,593 :GreatBrita in Oct. "4, i944

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