Abstract: Method and apparatus for forming halftone images which enables image recording on a process film without reducing the size of the recording area beyond that which is necessary. The method and apparatus is preferred particularly in the preparation of a master printing plate such as a printing plate which includes a photosensitive member having an organic silver salt. According to the method and apparatus, an image recording apparatus propagates error data when there exists a restriction on the minimum recording size and thereby preserves halftone concentration and reproduces intermediate gradation of darkness with stability.

Abstract: A scanning optical apparatus comprises a light source unit, scanning means for deflecting a beam from said light source unit and scanning a scanning surface with the beam, means for detecting the beam scanned on said scanning surface and control means for controlling the beam scanned on said scanning surface in a direction perpendicular to said scanning surface on the basis of a magnitude and a change as a function of time of a signal output from said detecting means.

Abstract: A scanning optical device for scanning a material to be scanned with a beam emitted from a light source thereof, has a storage device for storing information relating to the quantity of deviation of a scanning optical system. The convergent position of the beams is adjustable in the direction of the optical axis by at least partially controlling the elements of the scanning optical system in accordance with information relating the quantity of deviation supplied by the storage device. The quantity of deviation such as curvature of field of the scanning optical system can be compensated by a simple structure. Therefore, a recording device or reading device employing the scanning optical system exhibiting high resolution, low cost and a capability of preventing deterioration in the gradation expression can be realized.

Abstract: The information recording method of the present invention comprises steps of recording information on a recording medium by a recording head during forward movement, reading the information recorded during the forward movement in the opposite sequence to the recording sequence during backward movement, and checking if the information has been correctly written or not based on the information read during the backward movement.

Abstract: A scanning optical system is provided with a deflector for deflecting a light beam, a medium to be scanned by the light beam deflected by the deflector, and an imaging optical system disposed between the medium to be scanned and the deflector. A linear image near the deflecting - reflecting surface of the deflector and a point on the surface of the medium to be scanned are in a conjugate relation through the imaging optical system. The imaging optical system is such that the angle which the optical axis of the imaging optical system forms with respect to the optical axis of the light beam incident on the deflector in a plane parallel to the deflecting plane of the light beam is chosen so that a ghost image is formed in the direction of the scanning line of the medium to be scanned and outside the effective scanning area.

Abstract: In an optical information recording medium of the type wherein information is recorded or reproduced when a light beam scans each of a plurality of mutually parallel tracking tracks, an auxiliary track is extended between the adjacent tracking tracks and has at least one portion in parallel with the tracking tracks. In a method of recording or reproducing information by scanning a light beam on each of a plurality of mutually parallel tracking tracks on the recording medium, the recording medium has an auxiliary track which is extended between the adjacent tracking tracks and which has at least one portion in parallel with the tracking tracks and the light beam is kicked in the parallel portion of the auxiliary track.

Abstract: There is disclosed an optical card recorder-reader, in which erroneous signal recording, caused by a low-level light beam when it is stopped at a position for a prolonged period between writing and/or reading operation, either by interruping the irradiation, or by reducing the power of irradiation, or by placing the light beam outside the recording area, when the recording or reading operation is not in progress.

Abstract: A scanning optical system which is provided with a deflector for deflecting a light beam, a medium to be scanned by the light beam deflected by the deflector, and an imaging optical system disposed between the medium to be scanned and the deflector. A linear image near the deflecting - reflecting surface of the deflector and a point on the surface of the medium to be scanned are in a conjugate relation through the imaging optical system. The imaging optical system is such that the angle which the optical axis of the imaging optical system forms with respect to the optical axis of the light beam incident on the deflector in a plane parallel to the deflecting plane of the light beam is chosen so that a ghost image is formed in the direction of the scanning line of the medium to be scanned and outside the effective scanning area.

Abstract: A scanning optical apparatus comprises a light source unit, an optical system for converging a light beam from the light source unit at a predetermined position, a moving device for moving the converged position of the light beam by the optical system, a deflecting device for deflecting the light beam from the light source unit in a predetermined direction, a light receiving device for receiving the light beam deflected by the deflecting device, a processing device for processing a signal obtained by said light receiving device, and a control device for controlling the moving device corresponding to a signal from the processing device. The light beam emitted from the light source unit is scanned on the light receiving device a plurality of times through the optical system and the deflecting device, while the converged position of the light beam is moved by the moving device.

Abstract: A cleaning device comprises a cleaning member having a cleaning surface adapted to abut against a recording surface of an information recording medium, apparatus for holding the cleaning member, apparatus for moving the cleaning surface of the cleaning member, and apparatus for moving the hold means relative to the recording surface.

Abstract: An information recording-reproducing apparatus comprises a head, a first pair of rollers for guide-driving a recording medium relative to the head, a second pair of rollers for guide-driving the recording medium toward or from the first pair of rollers, and a controller for timingly controlling the first and second pairs of rollers. The first and second pairs of rollers are disposed at such an interval that the recording medium may not be caught by both of the first and second pairs of rollers at a constant velocity movement of the recording medium.

Abstract: An information recording and reproducing apparatus comprises a mount table on which an information recording medium is mounted, a structure for reciprocating the mount table relative to a recording and reproducing head, and an energy storer for decelerating the mount table in a deceleration mode, storing an energy generated during the deceleration and transducing the stored energy to a kinetic energy of the mount table in an acceleration mode to accelerate the mount table.

Abstract: An optical information recording and reproducing apparatus comprises, an optical head for recording and reproducing information on and from a card-shaped optical recording medium, first means for relatively reciprocally moving said optical head to said card-shaped optical recording medium, and control means for controlling a relative speed between said optical head and said optical recording medium, said control means keeping a constant relative speed between said optical head and said optical recording medium in a record area of said optical recording medium and changing the relative speed between said optical head and said optical recording medium and reversing the direction of the relative movement between said optical head and said optical recording medium in areas outside of the record area.

Abstract: Method and apparatus for recording information on a card-shaped optical information recording medium with a light beam and/or for reproducing information recorded on the medium. The apparatus includes a device for irradiating the medium with a light beam, a device for causing relative reciprocal movement between the medium and the light beam, and a device for terminating or displacing the light beam on the medium, after the lapse of a predetermined period of time from a moment when the relative speed of the medium and the light beam is reduced below a predetermined speed. The method includes the steps carried out by the apparatus.

Abstract: An information recording-reproducing apparatus includes a holding bed for holding a card-like or sheet-like information recording medium, a head for recording information on the information recording medium or reproducing the information recorded on the information recording medium, a device for reciprocally rectilinearly moving the holding bed relative to the head, and a device operatively associated with the movement of the holding bed, reciprocally moving a body of a predetermined weight. The device prevents shock during the reversal of the holding bed.

Abstract: In an information recording medium according to the present invention, marks for discriminating between information tracks and a mark indicative of the information concerning spacing from a position at which each of the marks is provided to the recording starting position are provided in an information block, and a plurality of such information blocks are continuously provided in the other area of the information tracks than the recording area. The specification also discloses an information recording and reproducing method and apparatus utilizing such a plurality of information blocks.

Abstract: An optical element whose focal length is variable comprises a medium whose refractive index is variable by temperature, a heating device for imparting heat to the medium to cause an index gradient resulting from a temperature distribution to be created in the medium, and a device for controlling the amount of heat imparted to the medium by the heating device to vary the shape of the index gradient formed in the medium.

Abstract: An information reproducing system is disclosed. This system is arranged such that information is read out from a recording medium having different types of first and second items of information and is output in the form of a signal. The waveform of the output signal is shaped and supplied as a reproduced signal. In the above-mentioned signal processing, this information reproducing system is adapted to control the shaping of the signal waveform in accordance with each type of information to be read out from the recording medium.

Abstract: A variable aberration imaging optical system comprises an imaging optical system and an optical device disposed in the optical system and capable of controlling the imaging characteristic of the imaging optical system. The optical device has a medium for forming an index gradient therein by heat, and a device for imparting heat to a desired position on the medium.

Abstract: This specification discloses a light modulating device comprising a liquid medium whose physical properties are variable by heat, and a heat-generating element for heating the liquid medium to such a degree that boiling does not occur to the liquid medium. The specification also discloses a light modulation apparatus comprising a liquid medium whose physical properties are variable by heat, a heat-generating element for heating the liquid medium to such a degree that boiling does not occur to the liquid medium, and a optical system for taking out one of a light flux modulated by the variation in physical properties of the liquid medium and a light flux not modulated by said variation from a state in which the light fluxes are mixedly present.