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MAY 16, 2008 |
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35mm / 70mm Projector DP-75 The DP 75 projector has been designed for the reproduction of 35 mm and 70 mm films. The precision intermittent movement and film mechanism have been especially developed for the high mechanical stresses made by 70 mm film. The special construction of the film gate assures a stable picture and prevents film buckling. NOTICE: THIS MACHINE IS OUT OF PRODUCTION AND HAS BEEN SUPERSEDED BY THE
FP-75E. Parts are still available for most versions.
Features:
Construction The DP 75 projector is built in a solid steel column that contains the film mechanism, the optical and magnetic sound heads and the wiring, which includes the lamphouse connections. The steel column pivots in a rigid base and can be tilted +15º or -25º to accommodate almost all projection situations. Film run mechanism The film run mechanism and the separately mounted intermittent movement run in an enclosed oil bath. The motor drives the intermittent movement via a toothed belt. A vertical shaft with helical gears drive the feed and take up sprockets and the shutter. The sprocket above the magnetic sound head and the take up reel are driven by silent chains. The framing is effected bythe movement of a muff coupling, which is inserted between the cross shaft and the intermittent sprocket. Synchronous or asynchronous motors can be used as drive motors. All gears are cut from high quality steel to ensure long life and minimum wear. A ring magnet is placed next to the drain plug in the bottom of the oil bath to collect any stray steel particles. All guide rollers and sprockets, except the intermittent sprocket, have flanges for both 35 mm and 70 mm film, so that even badly damaged prints are guided safely through the projector. Lateral guidance in the film gate is obtained by two pairs of ceramic discs, one pair above and the other below the aperture. These prevent film weave in the gate. Synthetic Delrin is used for the runner strips in the film gate, pressure skates and pad shoes to prevent film disengaging from the sprocket teeth. Delrin has been chosen because emulsion residues do not adhere to it. All 35 mm and 70 mm sprockets, guide rollers and sound drums only make contact with film outside the image and soundtrack areas. The film path has been designed so that all changes of film direction follow the minimum possible radius and each curve has a very gradual transition from one to the next. This is extremely important for smooth, safe passage of film splices. All parts of the drive mechanism have been manufactured to the highest possible precision and can be easily replaced. Film gate It is common knowledge that the difference in shrinkage between the emulsion and the film base tends to cause buckling. The emulsion side has a concave curvature at right angles to the direction of transport. Wherever the luminous flux and associated heat radiation is high, the emulsion tends to expand during illumination in the aperture and the emulsion surface becomes convex. This well known phenomenon called heat flutter affects each single frame and therefore the distance between lens and film is continually changed. By the shape of the runner plates and pressure skates, the film edges are pushed into one plane at the aperture. Directly above and below the aperture the gate is curved at a sharp angle to the lens. Because the film tends to maintain as uniform a curvature as possible while running, the film curves in the center of the image towards the light. Thus the buckling is avoided when the film comes under heat, and the residual curvature is so slight that the picture remains within the depth of focus of the lens. The film gate for 70 mm has a single, easily replaceable aperture plate and the 35 mm gate a vertically adjustable plate with three apertures for normal, wide screen and Cinema Scope. The different apertures are locked in place after selection. The film gate assembly is equipped with a water cooling system in order to prevent overheating. Quick conversion from 35 mm to 70 mm All rollers in the DP 75 projectors are dual profiled for both film gauges. All the sprockets, guide rollers and sound drums have a double profile so that they are suitable for either gauge of film. The only parts that need to be changed are the pad shoes, the film gate assembly and the projection lens. The pad shoes can be easily removed and are kept in place by a spring clip. The complete film gate consists of a carrier plate with Delrin runner strips and ceramic guide rollers, the aperture plate and a film gate with pressure skates. This unit can be easily removed in its entirety for conversion from one film gauge to another. Stop rings on the lens barrel assure a lens change without change of focus. The reel shafts can be changed without tools so that shafts with a diameter of 1/2" for 70 mm or 5/16" for 35 mm film can be changed quickly. Lens holder Lenses with a diameter of 4" (101.6mm) are directly inserted in the lens holder. The focus position can be fixed by a stop ring and the center position of the lens holder is marked with a reference mark. Smaller diameter lenses are mounted in an intermediate ring which has also a stop ring to ensure accurate focus. An optional motorized lens turret with automatic change of apertures for two 70.6mm lenses can be used instead of the lens holder for 35mm. Electrical unit The electrical controls in the DP 75 projector are mounted in the front of the projector column. Easily accessible, it can be set for 120 or 220 volts as well as for 50 Hz or 60 Hz. The push buttons for start and stop and change-over are mounted at the front of the projector. The DP 75 projector can be operated from an optional remote control panel or by automation with sensors to read cues on the film. Light sources The lamphouse cables are included in the main wiring in the projector column. Lamphouses for Xenon lamps of 1600W, 2000W ~ 4000W, and 7000W can be mounted on the lamphouse bracket supplied with the projector. A cylindrical lens can be inserted for spreading the light beam to fill the 70 mm format. Sound The 6 track magnetic sound head is a self contained unit mounted on the front side of the projector column. A driven feed sprocket between the take-off spool and the first rotating sound drum, two independent flywheels, a spring tension roller and a carefully designed film path provide wow and flutter-free sound reproduction. The flywheel stabilized optical sound head has an extremely short start-up time. High quality slit optics, a quick change pre-focus exciter lamp and a practically indestructible solar cell are features of our modern cinema technology. NOTICE: THIS MACHINE IS OUT OF PRODUCTION AND HAS BEEN SUPERSEDED BY THE FP-75E. Parts are still available for most versions. Special versions For large screen and dome projection, various special versions with modified gearboxes and special film gate assemblies are available:
The projector can be installed in a vertical as well as in horizontal positions. Technical data - Standard Unit
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