Abstract: An optical device includes a scanning means, a first image-formation optical system, and a second image-formation optical system. A system for a device, such as the one in which images are formed by scanning with this optical device. The scanning means scans a light beam emitted from a light source. The first image-formation optical system forms the light beam, scanned by the scanning means, into an image in a first spot diameter with respect to the scanning direction, on a surface to be scanned. The second image-formation optical system utilizes the first image-formation optical system and at least part of an optical system for forming the light beam scanned, by the scanning means, into an image in a second spot diameter which is different from the first spot diameter, with respect to the scanning direction, on the surface to be scanned.

Abstract: A mixture is prepared by mixing carriers to which a substance specifically reacting on an object substance adheres with a sample containing the object substance. The mixture is irradiated by light having an intensity gradient to concentrate the carriers at and near the irradiated positions by the optical pressure of the light. The efficiency of an agglomeration reaction of the carriers is thereby increased. A qualitative or quantitative measurement of the object substance is performed by detecting a state of agglomeration of the carriers within the mixture.

Abstract: Molten resin is ejected from the gate provided in the wall of a mold, which corresponds to the face of the head insertion opening of a disk cartridge, so that the molded half of the disk cartridge has scarcely any defect in the surface thereof.

Abstract: A structure in which a bail arm assembly consists of a bail arm, a bail arm cam and an arm supporting plate. The bail arm is energized to turn in the direction of the arm folded position. The reverse side of the bail arm cam is butted against by a kick lever projected out through an opening of the peripheral wall of a rotor. The bail arm cam has at its circumferential edge a recess for receiving the outer end of the kick lever when the arm is retained in the line detaching position and at its reverse side a protuberance for engaging with the same outer end when the arm is retained in the line holding position. The engagement between the protuberance and the outer end of the kick lever is released by pushing down the kick lever through an operating button portion thereof, whereby the bail arm can be folded down to one side of the reel body.