Abstract: A light attenuating device includes a housing, a first filter, a first motor configured to move the first filter, and a pneumatic actuator configured to move the first filter to either be in contact with the housing or to not be in contact with the housing. The filter includes multiple slit openings that vary in width such that the amount of light that passes through the multiple slit openings varies as the first filter is moved. The light attenuating device may also include a second filter and a second motor configured to move the second filter. A method of light attenuation is also disclosed that includes adjusting the position of a filter such that a portion of the filter is irradiated by a radiating beam, and while maintaining the irradiation of the portion of the filter, moving the filter to be in contact with a thermally conductive object.

Abstract: An apparatus calibrates the optical sensor to calibrate the distance measured by the sensor with the expected distance using a calibration surface at the expected distance.

Abstract: An image processing device is adapted to be provided with a photographing device configured to generate image data by photographing a print pattern and to output the image data, vertical synchronization signals, and horizontal synchronization signals. The image processing device includes: a first processor configured to, based on the synchronization signals, determine occurrence of abnormalities of the image data that is input, a memory including two storage areas, and a second processor. The second processor is configured to perform for each frame of the image data an addition process while exchanging a first storage area and a second storage area different from the first storage area of the memory with each other.

Abstract: An image recording apparatus (1) causes a recording head (20) to move through a distance corresponding to one half of the recording width of the recording head (20) in a sub-scanning direction each time a recording drum (10) makes one rotation. This, light emitting devices (23, 24) record two line data in advance, and thereafter following light emitting devices (21, 22) record the same line data repeatedly at the same position. This increases the energy of laser light beams given to a recording position on a printing plate (P) to accomplish the recording of an image with reliability. The recording speed is not extremely decreased because not all light emitting devices (21 to 24) are used to make the repeated recordings at the same position on the printing plate (P). Further, the construction of optical systems and driving systems in the image recording apparatus is not complicated.

Abstract: The present disclosure provides a method for measuring lens contamination in a lithography apparatus. The method includes imaging an asymmetric pattern utilizing a lens system and measuring an alignment offset of the asymmetric pattern associated with the lens system. A contamination of the lens system is determined by comparing the alignment offset to a reference value.

Abstract: An electrical dimmer device and its driving method applicable to, for example, an image pickup unit and a display unit operate so that when a control signal for stop adjustment is changed from its current value of stop adjustment to a larger value, which occurs when the light transmissivity of a positive type liquid crystal is raised, or when the light transmissivity of a negative type liquid crystal is lowered, the control signal is temporarily varied to an intermediate value that is larger than the larger value. The energy of the varied larger value and a time during which that varied value is applied are determined in accordance with predetermined values. By doing so, it is possible to make a response speed when changing the light transmissivity extremely faster and thus attain a response time, of for example, one field period of time or less required for a stop mechanism of a video camera.

Abstract: It is an object of this invention to provide an image input apparatus, image input system, light source control method, and storage medium capable of providing on the market an image input apparatus which greatly reduces the time before actual reading starts and which can be easily used in a manner based upon the energy saving standard. To achieve this object, the image input apparatus includes internal and external light sources for irradiating an original, an internal light source light amount controller for turning on/off the internal light source, an external light source light amount controller for turning on/off the external light source, a CCD for reading an original irradiated with light, a RAM for temporarily storing the read data, an interface circuit for transferring the data stored in the RAM to an external apparatus, and a CPU for turning on the light sources when an application program is enabled by the OS of the external apparatus.

Abstract: In accordance with the present invention, there is provided an image exposure apparatus whose installation area and height are reduced and which enables smooth conveying of a printing plate. In this image exposure apparatus, a cassette accommodating printing plates therein is loaded in such a manner as to be inclined at a predetermined angle, and preferably at an angle near 90°. A printing plate which has been taken out by a sheet unit is diverted in a curved manner and is sent to a recording section by a diverting unit. With this compact structure, the installation area and the height of the apparatus can be reduced.

Abstract: Provided is a method for producing image using a photothermographic material in which the photothermographic material is exposed with a laser light using an image producing apparatus having a recording section and heat developing section, and then developed by heating, the photothermographic material containing elsewhere at least on one plane of the a support at least one kind of photosensitive silver halide, a non-photosensitive organic silver salt, a reducing agent for silver ion and a binder; characterized in that the photosensitive silver halide contains an iridium compound, and the image producing apparatus has an exposure corrective control means for correctively controlling exposure output according to a temperature profile of photothermographic material within the apparatus. This method can provide an image with a stable quality while not being affected by environmental conditions during the image production.

Abstract: In a high speed package printer that produces photographs of varying size from film negatives, different cropping apertures are used with different lenses for different prints. In order to provide a large combination of different cropping apertures with different lenses the lenses and cropping apertures are separately selected for each print. The high speed package printer includes a light source, a diffusion plate, a plurality of cropping apertures on an aperture member which can be moved to select which aperture will block light from the diffusion plate. The light from the cropping aperture then passes through a negative for projection by a lens onto photographic paper for printing pictures. Separate means for moving the aperture member and for selecting which lens will receive light from a negative after it is provide a selection of all combinations of lenses and cropping apertures such that the photographs produced can have different sizes and shapes.

Abstract: A light valve has a pair of rotating vanes for controlling the cross section of a light beam passing between the vanes. The vanes rotate on corresponding shafts, each controlled by its own integral motor. Separate feedback control systems produce electrical control signals to each motor for rotating each shaft independently of the other to control the desired phase angles of the vanes. Error signals fed to variable gain amplifiers control the positions of the vanes. Whenever new commands are input to the variable gain amplifiers, amplifier gain is temporarily switched to a high gain mode, and after the phase angle of the shaft has stabilized, the amplifier gain is switched back to a low gain mode. The vanes are aligned on a common plane, and the vanes both rotate in an angular direction of rotation toward or away from the axis to reduce or enlarge the light opening between the vanes.

Abstract: An apparatus for forming an image comprises a plurality of light emitting elements each emitting light having substanitially the same peak wavelength as those of others; a conveyor to convey a recording medium to receive light emitted from the plurality of light emitting elements relative to the plurality of light emitting elements; and a controller to control the plurality of light emitting elements such that a single pixel on the recording medium is formed by light emitted from at least two pieces of light emitting elements.

Abstract: In a color image forming apparatus, a test pattern is formed by a color toner and provided with multiple tones by a dither method. The toner density of the test pattern is accurately read by a simple structure and faithfully corresponds to the actual toner density.

Abstract: A method of color balance determination for use by a color copying apparatus utilizing a gray estimate established as a functional relationship among at least three basic color density values measured from regions within multiple image frames of a film order. This functional relationship is preferably a fitted line to a set of measured density values from which density values from regions of high color saturation have been excluded. To discriminate these high color saturation regions, the color saturation is determined relative to a gray point calculated as a weighted average of minimum density and image average density values. Further improvement in the gray estimate is achieved by limiting the set of measured density values to regions of high modulance ("edge effect") within the image frames.

Abstract: A method of improving uneven illumination in a photographic printer having an original image position and a light source to illuminate the original image position, and an exposure position at which a light sensitive element is positioned for exposure, wherein the exposure position may have an inherent non-uniform illumination absent the original image, the method comprising:inputting into a computer, data representative of illumination at multiple laterally spaced locations positioned in a direction from the light source to the exposure position;processing the data in the computer to form an illumination correction function with a visually indistinguishable resolution.The illumination correction function is typically applied to an original image signal so that when the original image is printed and positioned at the original image position, the inherent non-uniform illumination at the exposure position is reduced. This corrected original image is then typically printed on a support.

Abstract: An exposure system for light sensitive materials held in a vacuum frame includes an electrical light source and a power supply to the light source, the power supply having a power consumption monitor so it can modify the power supplied to the light source to compensate for any fluctuations in power consumption by the light.The light source is supported in a housing having air exhaust openings proximate the mid-portion of the light source. A blower cools the light source with a helical airflow. The voltage drop across the electrical light source is used to control the speed of the blower to maintain the voltage of the light source at a desired level. The housing has an open face and a removable pane. An indicator indicates the presence of the pane. A metal shutter in the housing has a black ceramic surface adjacent the light source to selectively expose light sensitive materials. A control means closes the shutter when the indicator senses removal of the pane while power is being supplied to the light source.

Abstract: A photographic contact printing system comprises a data base in which certain exposure parameters (e.g., spectral response, sensitivity, dot-growth factor, nominal exposure value and overlay factor) of a variety of different photosensitive recording elements are stored. Upon selection of any one of such recording elements by a printer operator, a microprocessor automatically controls an exposure source (e.g. an electrically energizable lamp) to provide a pre-programmed exposure of the selected recording element. During exposure of the recording element, a logic and control unit receives a time-varying signal representing the instantaneous spectral radiance of the exposure source. The LCU integrates the exposure produced by the source until the integrated exposure matches a nominal (or an adjusted nominal) value, at which time the exposure is terminated.

Abstract: The present invention comprises a contact printer (10) which utilizes a flat tube monitor (30) connected with a computer (40) that permits the image or light array (32) projected by the monitor (30) to be manually and selectively altered in accordance with an operator's evaluation of the image (32) directed upon a negative (20). The operator may selectively dodge, burn, or offset the intensity of the image (32) so that an adjacent area of the negative (20) receives a corresponding alteration. The printer (10) enables the provision of custom contact prints made in accordance with the operator's evaluation of the light array (32) shining through the negative (20) so that the negative (20) is selectively modified acccording to the operator's desire.

Abstract: An image recording apparatus in which a color image of an original document is copied on a sheet of paper using a photosensitive recording medium and three mask members corresponding to red, green and blue color components. The mask members have light shielding images corresponding to color-separated images of the original document. The mask member is superposed on the photosensitive recording medium and the latter is exposed to the color-separated light component through the mask member. To provide a background-white color copies, detected is a transmission rate of the color-separated light component transmitting through the mask member and an amount of the color-separated light component applied through the mask member to the photosensitive recording medium is controlled in response to the detected transmission rate.

Abstract: A photographic exposure apparatus includes a lamp housing for a metal-halide discharge lamp for exposing a light-sensitive film to an image-bearing sheet when the lamp is energized to full power, a shutter for closing the lamp housing while the lamp remains energized at a lower power level in stand-by condition, and a control unit for energizing of the lamp in standby condition in such a way that, while being maintained at reduced power, the lamp is intermittently energized at high power during short intervals, e.g. in pulses, to thereby substantially prolong the working life of the lamp.

Abstract: A process for developing a film having one or more photographed image areas, so that the photographed image areas are developed under an optimum condition to have appropriate densities. In the first step, a region of the film, other than the photographed image areas, is exposed with a constant quantity of light. The region exposed to the constant quantity of light is then developed prior to the development of the photographed image areas. The density of the image in the region exposed to the constant quantity of light is detected and compared with a characteristic curve showing the change in density of the developed image in terms of the quantity of exposure light to find the optimum condition for development. The photographed image areas are then developed under the thus found optimum condition.

Abstract: A method of picture recording in which a surface of a photosensitive material is exposed to light containing a picture image and the exposed surface of the photosensitive material is superposed on an image receiving surface of an image receiving material so as to transfer the picture image obtained on the exposed surface of the photosensitive material onto the image receiving surface of the image receiving material. Judgment is then made as to whether the surface of the image receiving material to be superposed on the photosensitive material is the image receiving surface by using a detection device for detecting an absorption or reflection factor for light of a wavelength peculiar to the image receiving surface before the photosensitive material is superposed on the image receiving material, so that feeding of the image receiving material may be stopped when the judgment proves that the detected surface is not the image receiving surface.

Abstract: An apparatus for exposing photosensitive media is disclosed in which the light reaching or passing through photosensitive media is monitored, with the exposure being terminated after the desired amount of light has been received. Slope control circuitry is provided to selectively and non-linearly vary the exposure with variations in the density of originals which are being copied simultaneously. In a wide variety of applications the apparatus produces high quality prints, by automatically compensating for variations in exposure due to, for example, variations in the number of originals being copied.

Abstract: An integrating photometer for measuring total exposures to ultraviolet radiation. The circuit for the photometer includes a threshold limiter to suppress operation of the integrator until the illumination level exceeds a predetermined threshold. A power saving circuit turns the photometer off when no illumination is received during a predetermined time interval.

Abstract: A reproduction camera for the production of contact screen prints from an original is provided with sensing means, such as a photoelectric cell, for obtaining a measure of the light reflected by the original under conditions of an imagewise main exposure through the contact screen and a signal representing the obtained measure is inputted to a computerized control system through which, by taking into account the effect of stray light caused by reflection from the original during the main exposure, a non-imagewise additional exposure through the contact screen is effected so as to reproduce the minimum and maximum optical densities of the original with the correct dot sizes.

Abstract: An apparatus for exposing photosensitive media is disclosed in which the light reaching the photosensitive layer of the media is monitored, with the exposure being terminated after the desired amount of light has been received. A multiple exposure control is also provided which adjusts the relative exposures during first and second exposures of the photosensitive material. A special roller curtain mechanism is also disclosed. In addition, the apparatus includes a vacuum system for generating a vacuum, as the curtain descends with the vacuum being drawn between the blanket or curtain and a glass plate which supports the sensitized media and originals being copied. The surface supporting the sensitized materials is inclined to facilitate loading and unloading of the apparatus and also the operation of the curtain.

Abstract: A photographic printer light valve/fader control circuit may convert control data for conventional automatic solenoid driven photographic printer light valves to control data for high speed and reliable electronic photographic printer light valves and faders. The circuit is adapted to retrofit printers designed for existing solenoid driven devices and to convert the color and fade control signals received from a conventional paper tape reader to a form useful for electronic control of the angularly adjustable light valve vanes. The vanes adjust the mix of red, green and blue light in the resulting print and control fades, lap dissolves and the like. The color correction signals, received from the paper tape reader in a quasi-binary format, are converted into a conventional binary format and inputted at the proper time to two digital to analog converters which convert these signals into a form useful in controlling the angle of the vanes.

Abstract: An image density detecting device for an image forming apparatus includes a light diffusing member made of a transparent resin. The light diffusing member has a substantially rectangular sectional profile, with the longitudinal dimension thereof greater than the width of the document, and it is disposed below the document such that it extends in the width direction thereof. The side of the light diffusing member opposite its light receiving surface constitutes a diffusing reflecting surface which is formed by forming blade-like notches on this side. A photodiode is embedded in the end face of the light diffusing member on the side thereof opposite the ends of the blade-like notches.Light reflected by a portion of the document between the opposite edges thereof is received on the light receiving surface of the light diffusing member and is focusedly reflected by the diffusing reflecting surface toward the end face on the side of the photodiode to be detected thereby.

Abstract: An exposure indicator for photographic plate makers including a comparator having a control input, an inverting input and an output; a light emitting diode having its anode connected to the control input for developing a reverse bias signal at said control input in response to illumination from the plate maker light source whereby an output comparator signal is generated when the control input signal exceeds a reference signal at the comparator's inverting input; the output signal forward biasing the light emitting diode to its light emitting state and also fed back to the control input to maintain the light emitting diode in such emitting state; and vacuum operated switch means to provide power to the indicator circuit in response to vacuum actuation of the plate maker flexible blanket.

Abstract: A color photography printing process prints, a test print on the basis of color intensities of three color ranges transmitted through a small selected area of a test print. The exposure times for the three ranges are recorded besides the print in machine readable code. In the making of the final print the machine readable code controls the printing time. The times determined by the machine readable code may be corrected during the making of the final print by corrections determined by an expert observer of the test print.

Abstract: Disclosed is a device for dosing light from a light source in accordance with the intensity of light impinging upon a material to be exposed, comprising: a photosensitive element located in the beam path of the light source, comprising a photoresistor having an ohmic resistance inversely proportional to the intensity of light impinging thereon and providing an output voltage; a capacitor arranged in series with the photosensitive element; means, preferably in the form of a switch bridging the capacitor, responsive to switching-on of the light source for initiating charging of the capacitor; switching means arranged in series with said capacitor for varying the charging time thereof, whereby the exposure time of said material to be exposed can be varied by a predetermined ratio to produce a desired shade of gray; optional means for amplifying the output voltage of the photosensitive element; means for comparing the output voltage of the photosensitive element with a reference voltage to produce an output signa

Abstract: Automatic control of exposure level and contrast correction for a photographic printer is disclosed. The printer uses dynamic masking achieved by modulating the intensity and velocity of a CRT scanning spot. A prescan is employed to evaluate the negative and establish exposure level and contrast grade excursion limits for the subsequent exposure. Different control systems are disclosed for contact printing and projection printing.

Abstract: An image formation apparatus includes a processing station for forming an image on a recording medium, input device for setting the density of the image formed on the recording medium to a desired value; a controller for controlling the power supplied to the process station in response to the input device setting to form the image of the desired density set by the input device; and a range-shifter for shifting the range of the power controllable by the controller to maintain the density substantially constant.

Abstract: A universal light intergrator/timer is provided for use with photographic equipment wherein several desired exposure intervals for each of a plurality of light sources may be preset and stored in a microprocessor for instant selection by the operator during a photographic operation.When a stable light source is used the system is arranged to function as a timer and counts pulses derived from the AC line to control the light source in accordance with the preset exposure intervals.When a light source is used whose wavelength and intensity varies during warmup, the system is arranged to function as a light integrator. To obtain light integration the current flowing in a photodiode, which is linear with respect to light output, is amplified and converted to variable frequency pulses which are counted by the microprocessor to control the light source in accordance with the present exposure intervals.

Abstract: A Programmable Computing Enlarging Exposure Meter determines printing and contrast grades and shadow speeds and contrast grades of photosensitive material measuring printing density and contrast of film in its light path, with its unique analog computer it determines the necessary contrast grade and the exposure time required to produce a print of the necessary density. All computations and determinations are performed internally without requiring user extrapolating in the dark with calculator dials and attached slide rules that are the practice with instruments designed for the purpose.The structure comprises a power supply, light measuring device, a light to voltage converter for converting the light measurement to one or more linearly proportional voltages having range of 1:10 between them.An operational amplifier produces fixed output voltage. An R.sub.1 inverting input variable log taper resistor calibrated against the paper speed and paper grade scales on the front panel, an R.sub.

Abstract: A photographic direct-print system for producing a screened print from a continuous tone negative. Fundamentally, the invention includes an enlarger having a main lamp associated therewith for receiving a negative and casting an image thereof upon an easel. Flashlamps are maintained in juxtaposition to the easel for further illuminating the same. A density read-out circuit, comprising a photodiode presenting an output to a digital volt meter, is included for measuring the light intensity of various areas of the image, such read-out determining the lens setting of the enlarger and the intensity of the flashlamps, as regulated by a power phase control circuit. A timer is included for controlling a period of simultaneous energization of the enlarger and flashlamps, the timer being controlled by a clock having a frequency which is dependent upon the intensity of the main lamp of the enlarger.

Abstract: A photographic printer includes light sensors for measuring optical characteristics of photographic film to be printed. Prior to printing, the output signals of the light sensors are monitored under one or more reference condition, and calibration values based upon this monitoring are derived and stored. During normal operation of the photographic printer the sensors provide measurements of the optical characteristics of the film, and the output signals of the light sensors are calibrated based upon the stored calibration values. The exposures are then controlled as a function of the corrected output signals.

Abstract: Automatic incremental control of the exposure of a photosensitive image-receiving material during contact or projection printing is achieved by the use of a scanning exposing light beam, such as that from a cathode ray tube, wherein both the beam intensity and its rate of deflection can be varied in response to signals derived from a photodetector which views the scanning light after its passage through each incremental area of the transparency being reproduced.Embodiments capable of combined control of the intensity and velocity, or the dwell time, of the scanning light beam are disclosed, together with means for controlling exposure level and contrast.

Abstract: A device giving automatically correct exposure times for printing photographs, based on the principle of reflected-light measurement and integration, with a light measuring probe which may project a cone of light on the printing plane to precisely show the location and the size of the measuring area which can thus be controlled and varied at will. The electronic circuit comprises a luminous over-range indicator lighting up when the device is operated in conditions of too low or too high illumination for the circuit to work within its limits of linear operation. A potentiometer can be set for the sensitivity of the photographic material used and a single switch allows both interruption of already initiated exposure cycles at any moment, and switching off the darkroom safelight at the same time powering the enlarger when it is wished to control light conditions and/or measuring zone location before printing, in order to avoid any chance of incorrect exposure times.

Abstract: The exposure control of a photographic copying machine has several detectors which are exposed to surrounding light as well as to original-modulated copying light to transmit first signals which denote the color composition and/or density of originals. The influence of surrounding light upon the first signals is compensated for by discrete circuits which generate and store second signals corresponding to those portions of first signals which are attributable to the influence of surrounding light upon the respective detectors. The second signals are subtracted from first signals during exposure of an original to copying light whereby the resulting third signals denote the color composition and/or density of the original as if the detectors were not exposed to surrounding light.

Abstract: This invention relates to improvements in photographic printing exposure meters, and particularly to such a meter and having a light sensitive cell which produces an illuminance dependant electrical signal used in an electronic circuit, together with inputs of other parameters of printing density, to calculate values of printing density corresponding to the input values. The parameters inputs are related to contrast grade and speed index of photographic paper, and time duration of exposure to the illuminance given by the light sensitive cell. The meter can be used to determine what exposure time is required, for a photographic paper having a particular contrast grade and speed index, to give a particular value of printing density at the measured illuminance.

Abstract: A printer control unit utilizes a microprocessor and a random-access memory for storing color and cuing information in order to eliminate the need for continuously reading a tape during the printing operation. The printer control unit utilizes a single tape reader and the microprocessor is programmed to permit color tapes, cuing tapes or composite tapes to be read by the single tape reader.

Abstract: A photographic printer includes light sensors for measuring optical characteristics of photographic film to be printed. Prior to printing, the output signals of the light sensors are monitored under one or more reference condition, and calibration values based upon this monitoring are derived and stored. During normal operation of the photographic printer the sensors provide measurements of the optical characteristics of the film, and the output signals of the light sensors are calibrated based upon the stored calibration values. The exposures are then controlled as a function of the corrected output signals.

Abstract: An automatic photographic printer includes a sensor system for providing density signals indicative of measured optical density of a photographic film at a plurality of defined areas of the film. Photographic films containing landscape type scenes, snow/beach type scenes, and other scenes which might be incorrectly identified as subject density failures, are identified. The identified films are excluded from receiving a subject density failure exposure correction, while the remaining films are subjected to an automatic subject density failure exposure correction which is derived from the density signals.

Abstract: A photographic printer includes an automatic film measurement system which provides measurements of a film negative at defined discrete or continuous areas. The measurement system includes a light source on one side of the film, an array of light sensors on the opposite side of the film, and a plurality of interchangeable first light-guiding modules. The interchangeable modules are used with different size film and are interposed between the film and the array of light sensors. Each module has a plurality of light-conducting channels which have their first ends exposed at the first surface proximate the film and have their second ends exposed at a second surface proximate the array. The pattern at the second surface corresponds to the array of light sensors so that the light sensors receive light from different portions of the film through the light-conducting channels. In preferred embodiments, a plurality of interchangeable second light-guiding modules are also provided for use with different size films.

Abstract: The exposure of film which changes its transmissivity as a function of the quantum of light to which it is subjected is controlled by sensing the intensity of the light transmitted through the film. From the sensed light the change in the light transmissivity of the film is determined and when that change has reached the desired level the exposure of the film is terminated. The exposure is instantaneously controlled and terminated only after the desired exposure level has been reached irrespective of the time required.

Abstract: A document reproduction illumination/exposure control system, for ascertang the photometric qualities of a document to be photographically reproduced and providing a responsive control signal for illumination and exposure parameters for a document reproduction apparatus, is comprised of a source of radiation for illuminating a document to be reproduced, a detector for receiving radiation incident from the document and generating a radiation-detected signal proportional thereto, storage devices for storing spectral response information regarding the image-recording medium upon which an image of the document is to be reproduced, and an illumination/exposure correction device for receiving a correctional signal representative of the correlation between the radiation-detected signal and the stored spectral response information, whereby illumination and/or exposure parameters for the reproduction apparatus may be appropriately balanced to account for variations in the spectral qualities of the document.

Abstract: Process and apparatus for duplicating on microfiche the intelligence appearing on a photoplastic microfiche master by irradiating the duplicate through the master with high intensity moderately collimated light. Photoplastic film having a relatively thick thermoplastic layer is used as the master. The master and the duplicate are separated by a gap of predetermined size, which gap can be filled by air, plastic, glass or any other transparent medium. Multiple light sources isolated from one another, are used and provision is made for absorbing and dissipating some of the heat before the light reaches the master. Means are provided for assuring relatively uniform light intensity across the entire recording face and for assuring consistent irradiation of the duplicate irrespective of lamp age or line voltage variations.

Abstract: This invention relates to a control device, suitable for use to control the exposure of a light-sensitive material in a copying apparatus for the preparation of a printing plate, which comprises program store means for predetermining a basic exposure, input line means for connection to a photocell for measuring the luminous intensity of a light source in the copying apparatus, comparator means having its input connected to an output of the program store means and connected by a transmission path means to the input line means, the output of the comparator means being connectable to a control switch for the light source, and the transmission characteristics of the path being variable in steps, adjacent pairs of which have transmissivities in the ratio .sqroot.2:1.

Abstract: Light emission regulation device according to which light which is emitted from a light source and is transmitted by an optical system onto a required object or objects is detected by a light detection element which is located externally to the optical system and produces or controls an output which is proportional to light incident on the light detection element and is supplied to a control means which in response controls actuation input to the light source whereby light emission is maintained at a requisite level. The light detection element being external to the optical system, light emission regulation is unaffected by the condition of elements of the optical system or material in the optical path over which light is transmitted.