Abstract: A plate fixed to a recording drum is irradiated with a laser beam emitted from an objective lens of a recording head, to generate gas. The recording head has a gas diffusion/suction unit forming an air stream in front of the objective lens. Further, a second suction unit elongated along the rotational axis of the recording drum is arranged between a transport unit supplying the plate to the recording drum and the recording head. Thus, it is possible to prevent the gas not only from contaminating the objective lens but also from diffusing in a housing following rotation of the recording drum. Consequently, an image recorder employing a photosensitive material generating gas in reaction to heat resulting from the laser beam emitted from the recording head can minimize contamination of the recording head, the transport unit etc. arranged in the housing of the apparatus with the gas.

Abstract: A plate fixed to a recording drum is irradiated with a laser beam emitted from an objective lens of a recording head, to generate gas. The recording head has a gas diffusion/suction unit forming an air stream in front of the objective lens. Further, a second suction unit elongated along the rotational axis of the recording drum is arranged between a transport unit supplying the plate to the recording drum and the recording head. Thus, it is possible to prevent the gas not only from contaminating the objective lens but also from diffusing in a housing following rotation of the recording drum. Consequently, an image recorder employing a photosensitive material generating gas in reaction to heat resulting from the laser beam emitted from the recording head can minimize contamination of the recording head, the transport unit etc. arranged in the housing of the apparatus with the gas.

Abstract: In a multi-beam drawing method in which drawing is performed with a plurality of light-emitting devices (LDs), it is detected whether any LD is damaged. Of a plurality of partial LD lines obtained by partitioning at a damaged LD or LDs, the partial LD line including the largest number of LDs is selected as an effective LD line for use in drawing. Spiral correction is performed by dividing image data to be supplied to the LDs into a plurality of virtual small images parallel to the sub-scanning direction which are shifted in a reverse direction to the sub-scanning direction.

Abstract: A first data rate detecting portion sends a first data transfer rate on a first interface, and a second data rate detecting portion sends a second data transfer rate on a second interface, respectively, to a CPU. The CPU compares the first and second data transfer rates and sets a connection state of a selector so that the image recording onto a photosensitive material is made at a high speed. The CPU also respectively determines the optimal rotation speeds of a polygon driving motor and a roller driving motor from the first or second data transfer rate, and rotates the polygon driving motor and the roller driving motor at the optimal rotation speeds. Then, when image data is inputted, an image is recorded on the photosensitive material.

Abstract: Halftone dots are formed on the basis of three sets of screen pattern data assigned to the to a same combined area, in which a plurality of halftone dots are to be formed. The three sets of screen pattern data have different threshold values assigned to respective pixels in the combined area, and are stored in SPM's (101-116). Eight SPM's (Screen Pattern memory units) store a first set of the screen pattern data, six SPM's store a second one, end two SPM's store a third one. One of the sixteen SPM's is randomly selected with respect to each pixel, whereby one of the threshold values (D.sub.s) stored in the selected SPM is compared with an iamge signal (V.sub.1). A dot signal indicating whether or not each pixel is solid is produced on the basis of the comparison. Accordingly, a grid-like pattern of halftone dots to be seen in a highlight area or a shadow area is prevented.

Abstract: A clock generator (15) and a delay circuit (16) create N dot recording clock signals (.phi..sub.1 to .phi..sub.N) of a cycle t, delayed by t/N. A counter (20) counts a detecting time interval between a start sensor (12) and an end sensor (14) for every surface of a polygon mirror (8) to generate time resolution t/N. The difference between the count value and a reference count value set in a latch (24) is input to a subtracter (23), so that a translation table (28) outputs clock crossover timing responsive to the difference. A latch (17) and an encoder (18) select an N dot recording clock signal synchronous with detection output of the start sensor (12) for every surface of the polygon mirror (8). A second selector (33) outputs a crossover dot recording clock signal (.phi..sub.X) for image recording by performing crossover from the selected dot recording clock signal to other dot recording clock signals that are sequentially along the clock crossover timing.

Abstract: Photosensors having light emitting elements and light receiving elements are provided in a path for carrying a film. The light emitting elements emit periodic pulsed light. When the film is present in the positions of the photosensors, the periodic pulsed light is reflected by the film to enter the light receiving elements, whereby presence of the film is detected. Activation time and activation interval of the light emitting elements for generating the periodic pulsed light are determined so that accumulated exposure value in each portion on the film is less than a critical exposure value of photosensitive material provided in the film.

Abstract: A clock generator (15) and a delay circuit (16) create N dot recording clock signals (.phi..sub.1 to .phi..sub.N) of a cycle t, delayed by t/N. A counter (20) counts a detecting time interval between a start sensor (12) and an end sensor (14) for every surface of a polygon mirror (8) to generate time resolution t/N. The difference between the count value and a reference count value set in a latch (24) is input to a subtracter (23), so that a translation table (28) outputs clock crossover timing responsive to the difference. A latch (17) and an encoder (18) select an N dot recording clock signal synchronous with detection output of the start sensor (12) for every surface of the polygon mirror (8). A second selector (33) outputs a crossover dot recording clock signal (.phi..sub.X) for image recording by performing crossover from the selected dot recording clock signal to other dot recording clock signals that are sequentially along the clock crossover timing.

Abstract: A method and apparatus for correcting the reciprocity law failure of a photosensitive material to be exposed, for use in a picture reproducing machine such as a process camera are disclosed. Luminous energies of an original picture and a standard picture are detected by a light detector, and then the exposure luminous energy is compared with the standard luminous energy by an arithmetic unit. Then, an exposure time is calculated in a calculator by using the comparison result and fundamental data such as the standard luminous energy, a standard exposure time predetermined, and a correction factor predetermined, which are recorded in data setup means.

Abstract: A color correction apparatus for a duplicate camera wherein three color correction filters of three primary colors are provided and are selectively interposed into the exposure light path, is disclosed. An arithmetic unit is connected to a color correction value setup means which sets up color correction values of colors to be removed from an original picture, and it receives these density values as negative values and subtracts the minimum value thereof from each of the other density values to outputs a color correction signal. Then, a control unit connected to the arithmetic unit controls the color correction filters so that they may be interposed into the exposure light path according to the color correction signal.