Abstract: An athermally compensated printhead includes a laser diode having predetermined characteristics for generating a beam of light, a diode mount, cooling means, a collimator lens, and a len mount. The diode mount is formed of a predetermined material with a predetermined coefficient of thermal expansion for mounting the laser diode in the printhead. The cooling means is used to maintain the laser diode at a substantially constant operating temperature for longer life and to avoid wavelength changes. The collimator lens has characteristics which provide predetermined changes in focal length versus changes in ambient temperature over a predetermined temperature range. The len mount is formed of a predetermined material having a predetermined coefficient of thermal expansion for mounting the collimator lens adjacent a first major surface of the diode mount to receive the beam of light from the laser diode.

Abstract: There is described a simple and inexpensive circuit for a thermal printing system which provides various test and diagnostic image patterns. The circuit includes a dual-port RAM, an address counter, a handshake logic unit and a multiplex switch unit. The image patterns provided by this circuit, which are applied to the printing system at high speed and in real time (e.g., 10 m bits/sec.), visually verify the precise mechanical and electrical adjustment, normal operating performance, and the high quality print output of the overall printing system. Various test images are easily programmed off-line into this electronic circuit. This circuit, with its printed test images, provides a highly useful tool in the initial set-up and the subsequent maintaining of the operation of the printing system.

Abstract: There is disclosed an interferometric system including electro-optical apparatus and method for examining and characterizing ultra fine details of various specimens such as a piece of photographic film. The method includes illuminating a specimen with a thin wide substantially pure Gaussian light beam, detecting the interfering patterns of light from the specimen, and characterizing ultra fine details of elements of the specimen by means of the detected light patterns. The apparatus includes a laser, a magnifying telescope, a multi-prism beam expander, and a linear array of photo-diodes. Signals from the photo-diodes are displayed on an optical multichannel analyzer (OMA) to provide a waveform characteristic of ultra fine elements of the specimen. Both "near-field" and "far-field" characterizations are possible and details of elements having diameters of the order of the wavelength of the light used (e.g., about 0.6 .mu.m) are detected.

Abstract: Apparatus and associated methods employed therewith for accurately providing a desired ("Aim") tone reproduction characteristic in an output image through a DDCP (direct digital color proofing) imaging chain (such as that implemented by a raster image processor (200), particularly a screening process (660) occurring therein, and a marking engine (130)) and for significantly reducing the number of test proof images that need to be produced and measured to achieve this result. Specifically, "Benchmark" operating conditions and intrinsic performance (i.e. "Benchmark" entry point data) of the DDCP imaging chain thereat are first defined.

Abstract: A high resolution scanner is disclosed which is adapted to digitally record an image from photographic film. The scanner comprises a folded integrating sphere which projects illumination on the film as the film is moved relative to the integrating sphere. Light transmitted through the film is directed to a photodetector by an optical system. In order to produce an aberration-free image on the photodetector, the illumination projected on the film is in the form of an arc, and a unit magnification optical system transmits light to a photodetector having image sensor elements arranged in an arc.

Abstract: An imaging system comprising a source of light movable with respect to a writing element and projectable thereon to generate an image, a focusing means is provided for focusing a light source which generates a first beam of light of a wavelength selected to be actinic with respect to the writing element. At least a portion of the first beam of light is absorbed by the writing element. The apparatus comprises means to automatically supply donor sheets and receiver sheets independently to a writing platen or drum, and to selectively load and unload the donor sheets from superposition with the receiver sheet without disturbing the registration of the receiver sheet. Also included are components which contribute to the quality of the images generated, such as relatively inexpensive, low jitter transports and drives for the writing head and imaging drum.

Abstract: A roller over which advances a web of material such as paper, photographic film or the like includes a plurality of staves organized in first and second arrays with the staves of the first array alternating with the staves of the second array to provide surfaces for supporting the web. The staves are each individually mounted on the roller by separate spring legs which center the staves. Flanges are located at the ends of the roller to position the web laterally. When the web obliquely approaches the axis of the roller so as to helically advance thereover, the staves sequentially and independently shift axially due to engagement with the helically advancing web. After the web leaves the roller, the stave that the web was most recently supported by returns under the bias of the spring legs to its central, unbiased position. In this way, damage to the edges of the web, due to engagement with the flanges, is minimized.

Abstract: A method is disclosed for recording and reading a color image formed on a receiving medium such as a film coated with a blue metastable colloidal silver. Upon application of heat to selected areas of the coating, the blue silver turns yellow to form an image. In a record mode, a modulated beam from a diode laser is scanned onto the receiving medium to form an image. In a read mode, a diode laser beam containing two different wavelengths of radiation is scanned across an image on the recording medium. In order to detect errors in the image, a detector senses the two wavelengths at each pixel and produces signals indicative of the densities of the yellow and blue in the pixel. Signal processing determines valid data points from the two signals.

Abstract: A donor element for laser color transfer processes includes a heat absorbing layer including a combination of a metal layer with an antireflecting layer having an index of refraction greater than 2. The heat absorbing layer may include a metal or an alloy either in single or multiple layers having a thickness sufficient to yield a heat capacity of less than 0.2 calories per degree Centigrade per square meter and an optical density at the laser wavelength of 1.0 or greater.

Abstract: Focus apparatus is disclosed for use as a focus error detector in an optical system. The apparatus comprises two polarizer elements of different polarization disposed at the pupil of a focusing lens. A detector is positioned at an image plane to intercept a beam from the lens and polarizer elements. The detector includes a detector element which is adapted to detect radiation in four quadrants, and an analyzer which is disposed in front of the detector element. The analyzer includes two polarizers of different polarization arranged at right angles to the polarizers disposed at the pupil of the lens. An electronic circuit is coupled to the detector for producing a focus error signal.

Abstract: There are disclosed an apparatus and a method for thermal printing by dye transfer of a high definition image on a receiver element such as a full color slide transparency. This new thermal printing apparatus includes a laser, means to scan a finely focused spot of light from the laser along a line, means to position a dye donor element and a closely adjacent receiver element (side transparency) to be scanned by the laser light spot, and laser drive and control logic (LDCL) means for turning the laser full-on to an optimum power level for a time determined by high speed print data in the form of data words. The method according to the invention includes the step of applying to a dye donor element thermal energy from a laser at a power level at which the dye ablates rather than sublimes. The laser is driven at an optimum power-on level and the length of time the laser is on determines the amount of dye transferred to a receiver element as a dye pixel.

Abstract: A method and apparatus for generating a dynamic focus correction voltage signal for a cathode ray tube which comprises the steps of: generating horizontal and vertical scan counter signals, and inputting the counter signals to a dynamic output voltage generating means which produces an output voltage that is proportional to the distance the scan is from the center of the image on the CRT in both the vertical and the horizontal directions.

Abstract: A beam scanning galvanometer is disclosed which oscillates a mirror in a non-resonant mode. The moving parts of the galvanometer are made with as small a moment of inertia as possible because the mirror is oscillated in a non-resonant mode. The galvanometer uses two sets of crossed leaf-springs to support the mirror instead of bearings which are usually used in non-resonant galvanometers. Each of the sets of leaf-springs is formed of a single strip of cold rolled stainless steel. The springs are embedded in uniquely shaped cavities in a permanent magnet that supports the mirror at a distance very close to an axis of rotation of the mirror. The mirror is specially shaped with beveled edges so that its moment of inertia is low and so that it can oscillate in very close proximity to a driving current coil which surrounds the mirror supporting magnet. A magnetic position sensor is used to detect an angular position of the mirror during operation of the galvanometer.

Abstract: A high resolution scanner is disclosed which is adapted to digitally record an image from photographic film. The scanner comprises a folded integrating sphere which projects illumination on the film as the film is moved relative to the integrating sphere. Light transmitted through the film is directed to a photodetector by an optical system. In order to produce an aberration-free image on the photodetector, the illumination projected on the film is in the form of an arc, and a unit magnification optical system transmits light to a photodetector having image sensor elements arranged in an arc.

Abstract: There is disclosed an automatically adjustable electronic drive circuit for a multi-laser thermal-printer to insure uniformity in printing by all of the lasers. Each circuit includes a semi-conductor diode laser, a power transistor for driving the laser, a light sensor, a current sensor, a digitally adjustable potentiometer bias level unit, a dual input power amplifier for driving the power transistor, and two D/A converters for applying threshold and enable (full-on) signal levels to the inputs of the power amplifier. A first data feedback loop from a laser current monitor through an external central processor unit (CPU) to one of the D/A converters sets the threshold drive current to the laser. A second data feedback loop from the light sensor through the CPU and the adjustable bias unit to the second D/A converter establishes the level of the enable drive current to the laser to obtain a precisely calibrated full-on light power output of the laser.

Abstract: An imaging system comprising a source of light movable with respect to an image carrier element and projectable thereon to generate an image, and an auto-focusing system for focusing the image-generating light source. The auto-focus system includes a second beam of light of a wavelength selected not to be actinic with respect to the image carrier element. The initial set up of the auto-focus system is enhanced by the use of the focusing system and a sensor for indicating the output of the focus photodetector to register a zero output which indicates the initial set position.

Abstract: A photographic material clamping apparatus includes a rotatable drum that has a longitudinally extending central axis, a longitudinal opening offset from the central axis, and a plurality of radial openings extending between the drum surface and the longitudinal opening. A cover member overlies the plurality of radial openings. A counterweight is positioned in the longitudinal opening and is connected to the cover member. Spring means act on the counterweight to urge the cover member towards the surface of the drum to grip a piece of photographic material inserted between the cover member and the drum.

Abstract: An imaging system comprising a source of light movable with respect to a writing element and a multiple laser diode and optical fiber assembly. Each laser diode and optical fiber assembly includes an optical fiber connected to a laser diode and guided through an inlet chamber, a cylindrical chamber, an outlet chamber and led out through a connector chamber where the fiber is connected to a connector member. The laser diode and optical fiber mounts can be readily assembled and serviced and yet provide the requisite safety against unwanted exposure to damaging light.

Abstract: An imaging system comprising a source of light movable with respect to a writing element to generate an image. A multiple laser diode and optical fiber assembly includes a pair of chambers for holding a plurality of diode assemblies. A channel-shaped member is disposed lengthwise between the two chambers. The channel member is provided with a plurality of connectors for connection with mating connectors at the end of the fibers in each of the diode mounts. The laser diode and optical fiber mounts can be readily assembled and serviced and yet provide the requisite safety against unwanted exposure to damaging light.

Abstract: In an imaging system comprising a source of light movable with respect to a writing element and projectable thereon to generate an image, a focusing means is provided for focusing a light source which generates a first beam of light of a wavelength selected to be actinic with respect to the writing element At least a portion of the first beam of light is absorbed by the writing element. The focusing means includes means for generating a second beam of light which is projectable onto the writing element and has a wavelength different than the wavelength of the first light beam. Means is provided which is responsive to the second beam of light to generate a signal to control the focusing means.