Abstract: A light guide member comprises three optical blocks. The first optical block is provided with a light input face positioned close to and approximately in parallel with a stimulable phosphor sheet carrying a radiation image stored therein, and a light output face parallel with the light input face. The second optical block is provided with a light input face slightly spaced apart from the light output face of the first optical block, a dichroic optical plane extending upward from one end of the light input face at an angle of approximately 45.degree., and a light output face extending downward from an upper end of the dichroic optical plane. The dichroic optical plane transmits stimulating rays and reflects light emitted by the stimulable phosphor sheet upon exposure to stimulating rays.

Abstract: In a system provided with a plurality of photomultipliers, the sensitivities of the photomultipliers relative to one another are detected by comparing the outputs of the photomultipliers generated under irradiation by light emitted from the same light source. The difference between the detected sensitivities relative to one another and predetermined sensitivities relative to one another is calculated, and the sensitivities of the respective photomultipliers are corrected so that the difference becomes zero.

Abstract: In a radiation image recording and read-out system in which a stimulable phosphor sheet is repeatedly used for recording radiation images, and noise developing due to residual radiation energy on the phosphor sheet is eliminated by exposing the phosphor sheet to erasing light prior to radiation image recording step, the level of residual radiation energy is detected, and the amount of exposure of the phosphor sheet to erasing light is controlled according to the detected level of residual radiation energy. The exposure amount is controlled to erase residual radiation energy to a level within the range between 0.01 and 0.0001 with the maximum of the originally stored radiation energy taken as 100.

Abstract: A stimulable phosphor sheet carrying a radiation image stored therein is scanned by stimulating rays which cause the stimulable phosphor sheet to emit light in proportion to the stored radiation energy. The emitted light is photoelectrically detected to obtain an electric image signal of the radiation image. A signal amount corresponding to after-glows emitted by the stimulable phosphor sheet and photoelectrically detected when the stimulating rays exist outside of the stimulable phosphor sheet after scanning along at least one scan line is conducted is subtracted from an amount of electric image signal photoelectrically detected when the stimulable phosphor sheet is scanned by the stimulating rays, thereby accurately obtaining an image signal representing the radiation image for use in reproduction of a visible image.

Abstract: A radiation image read-out apparatus comprises a stimulating ray optical system for exposing a stimulable phosphor carrying a radiation image stored therein to stimulating rays, a photodetector for detecting light emitted by the stimulable phosphor upon exposure to stimulating rays, and a light guide member for guiding the emitted light to the photodetector. A dichroic optical plane which selectively reflects either the stimulating rays or the light emitted by the stimulable phosphor and selectively passes the other is positioned in an optical path or the light guide member. The stimulating ray optical system is positioned so that the stimulating rays directly impinge upon the dichroic optical plane and come out of a light input face of the light guide member positioned close to the stimulable phosphor by being reflected by or passed through the dichroic optical plane.

Abstract: A photo-sensor, such as a photo-diode, is applied to the converging area of a flat type light transmission unit in an image read-out system, thereby intercepting a part of the scan light which falls on and travels through the light transmission unit after being reflected from an image-bearing sheet. The output signal from the photo-sensor can be advantageously used to detect arrival of the sheet edge at the scanning station, any scratches on the sheet and other operating conditions as required.

Abstract: A recording laser beam is intensity-modulated and is caused to scan a photosensitive recording material in both the main and sub scanning directions. The position of the recording laser beam on the recording material in the main scanning direction is detected and position reference pulses are generated each time the laser beam moves along the recording material in the main scanning direction by a predetermined constant distance. The recording laser beam is intensity-modulated only for a predetermined constant time interval between each pair of adjacent position reference pulses and is made essentially null for the rest time interval between the adjacent position reference pulses so that a unit area of the recording material corresponding to one picture element is exposed to the recording laser beam for a predetermined constant time interval regardless of fluctuation in the scanning speed of the recording laser beam.

Abstract: Disclosed is a method and an apparatus for detecting the leading edge of a sheet which is on the way to the scanning-and-reading station of an image read-out system. Detection is performed by exposing, just ahead of the scanning-and-reading station, the traveling sheet to the same scanning beam of light as used at the scanning-and-reading station, and by detecting the sudden change in the amount of reflection on arrival of the sheet at the station due to the difference between the reflection coefficients of the sheet and the underlying conveyer belt. Preferably, the scanning for detecting the leading edge of the sheet is at a higher frequency and smaller amplitude than the scanning for reading an image on the sheet.

Abstract: In a radiation image read-out system in which a stimulable phosphor sheet carrying a radiation image stored thereon is exposed to stimulating rays, and light emitted from the phosphor sheet is photoelectrically read out to reproduce a visible image, the gradient of a decay curve of the phosphor sheet is detected by exposing the phosphor sheet to stimulating rays and detecting the light emitted therefrom. Preliminary read-out for reading out image input information stored on the phosphor sheet is then conducted by using stimulating rays having stimulation energy lower than stimulation energy of stimulating rays used in final read-out. On the basis of the decay curve gradient and the image input information, read-out conditions in the final read-out and image processing conditions are set. The final read-out is conducted within one hour after the phosphor sheet is exposed to the stimulating rays for detecting the decay curve gradient.

Abstract: In a radiation image read-out system in which a stimulable phosphor sheet carrying a radiation image stored thereon is exposed to a stimulating ray which causes it to emit light in the pattern of the stored image, and the emitted light is photoelectrically read out, preliminary read-out is conducted to investigate the image input information on the phosphor sheet by use of a stimulating ray having stimulation energy lower than stimulation energy in final read-out for obtaining a visible image. The image input information is displayed, e.g., on a CRT to manually set final read-out and image processing conditions or directly sent to a control circuit for automatically setting them. Preliminary and final read-out sections are formed separately, or a single read-out section is used to conduct both read-out steps.

Abstract: In a radiation image read-out system in which a stimulable phosphor sheet carrying a radiation image stored thereon is exposed to stimulating rays which causes it to emit light in the pattern of the stored image, and the emitted light is photoelectrically read out, the interval between the radiation image recording on the stimulable phosphor sheet and preliminary read-out is measured, the image input information detected by the preliminary read-out is corrected according to the interval measured, and the final read-out conditions and/or the image processing conditions are set based on the corrected image input information. To determine the interval, a bar code label for identifying the phosphor sheet is attached thereto, and the time when the recording thereon is conducted is stored in a memory with respect to the bar code label. Or, a magnetic recording medium is attached to the phosphor sheet, and the recording time is recorded on the medium and read out therefrom at the time of preliminary read-out.

Abstract: In a radiation image read-out system in which a stimulable phosphor sheet carrying a radiation image stored thereon is exposed to stimulating rays which causes it to emit light in the pattern of the stored image, and the emitted light is photoelectrically read out, the phosphor sheet is uniformly desensitized by the exposure thereof to stimulating rays. Then, preliminary read-out is conducted by use of stimulating rays having stimulation energy lower than the stimulation energy of stimulating rays used in final read-out, and the final read-out conditions and the image processing conditions are set based on the image input information obtained by the preliminary read-out. The desensitization is conducted to eliminate 3% to 60% of the radiation energy stored on the phosphor sheet in order to obtain the image input information suitable for setting the conditions regardless of the interval between the radiation image recording and the preliminary read-out.

Abstract: In a system for reading out radiation image information recorded on a stimulable phosphor sheet which emits light upon stimulation by stimulating rays according to the recorded radiation image information, the phosphor sheet is two-dimensionally scanned by a laser beam and the light emitted therefrom is detected by a photodetector. The integrated output of the photodetector is read out for every unit of time period corresponding to a picture element of the radiation image. Position reference pulses are generated every time the relative position of the laser beam scans on the phosphor sheet by a standard amount in the main scanning direction. The integrated value of the output of the photodetector is read out every time the output is integrated for a fixed time period within each time interval between the position reference pulses.

Abstract: Image information stored on a recording medium is read out by photoelectrically converting light obtained by two-dimensional scanning of the image information, and integrating the electric signal by use of a plurality of integrators which are sequentially actuated each time a first clock pulse determining the picture element size is input. Integration periods are set not shorter than one clock length of the first clock pulse so that they partially overlap each other. The integration output is sampled by a second clock pulse at a point of time within the overlap region of the integration periods but outside regions where the next integrator is in the integration start transient and where the currently operating integrator is reset. The integrator reset period is set to sufficiently reset each integrator and prepare for the next integration.

Abstract: In a process of image recording by scanning a recording material with a light beam modulated by an image signal, the density of the recorded image is adjusted by controlling the light intensity during a predetermined interval using a clock pulse for picture elements, recording an image for a predetermined time within the predetermined interval, and changing the predetermined recording time for the entire image or only portions thereof. The recording time is changed in a very simple manner, for example, by operating a variable resistor.

Abstract: In a radiation image recording system in which a stimulable phosphor plate is first exposed to an imagewise radiation to store the energy of the radiation and record a latent image of a radiation image, the stimulable phosphor plate is then exposed to stimulating rays to emit light according to the stored energy of radiation, and the emitted light is detected to obtain an image signal, a radiation image read out device including a light source of stimulating rays and a photodetector to detect the light emitted from the stimulable phosphor plate upon stimulation thereof has a plurality of photodetectors. The plurality of photodetectors are divided into two groups. The output signal of one group is inversely amplified and the output signal of the other group is non-inversely amplified. The difference between the two output signals of the two groups is obtained by use of a differential amplifier to obtain an image signal free of quantum noise and electrical noise.

Abstract: In Reiss chamber method or ionography, or in a method of modification or combination of these methods wherein an electrostatic latent image of an object irradiated with radiations such as X-rays is formed on an insulating image recording layer, a photoconductive material is used as the image recording layer. The charge carried on the photoconductive image recording layer is partly neutralized by the radiations received thereby. In an embodiment, a fluorescent layer is attached to the photoconductive image recording layer to accelerate the neutralization of the charge when the recording layer is exposed to the radiations. In another embodiment, the photoconductive material has a property that the photoconductivity increases as the strength of an electric field applied thereacross increases, and the image recording layer made of such a photoconductive material is uniformly exposed to light simultaneously with or after the irradiation of the radiations.

Abstract: In an electrostatic powder coating method for coating a plate with electrostatic coating powder after or before the plate is provided with marking lines by electrophotographic print marking process, areas which are preferred to be free from the coating are not applied with the coating powder. After the coating powder is uniformly scattered on the plate, the powder is selectively removed to form a pattern shaped coating on the plate to form a non-coat area around the marking lines. In order to selectively remove the powder from the surface of the plate, a powder removing device which is controlled by a non-coating signal is used. The non-coating signal is given by a non-coating information output device. The non-coating information is recorded on an original which carries marking information for the electrophotographic print marking process.

Abstract: Disclosed is an electrostatic recording method for forming an electrostatic latent image on a dielectric electrostatic recording layer provided on a conductive support. The relationship between the thickness d[.mu.m] and the specific dielectric constant .epsilon..sub.s of the electrostatic recording layer is such that the ratio of d[.mu.m] to .epsilon..sub.s, i.e. d/.epsilon..sub.s [.mu.m], is not larger than 1.65[.mu.m] when the image recorded is of reflection type and not larger than 1.5[.mu.m] when it is of transmission type. The latent image formed on the recording layer is developed by use of electrophotographic liquid developer. Also disclosed is an ionizing radiation image recording method wherein ionizing radiation carrying image information is directed onto a material which generates photoelectrons or a gas which is dissociated upon receipt of the ionizing radiation to an extent corresponding to the intensity of the radiation.