Abstract: An optical power control apparatus includes a changing unit which changes, a plurality of number of times, the value of a current flowing to an optical beam output apparatus, and an obtaining unit which obtains, in correspondence with each current value, a peripheral optical power representing an optical power at the peripheral part of the spot of the optical beam output from the optical beam output apparatus. The optical power control apparatus also includes a correction unit which corrects the peripheral optical power so that the peripheral optical power and a central optical power representing an optical power at the central part of the spot have an approximately linear relationship in correspondence with each current value. The optical power control apparatus also includes a control unit which controls the optical power of the optical beam output from the optical beam output apparatus in accordance with the corrected peripheral optical power.

Abstract: A light scanning apparatus includes a plurality of light sources. A detection unit detects the light power of a light beam output from at least one of the plurality of light sources. A control unit controls the driving current of at least one selected light source on the basis of the detection result by the detection unit such that the light power of the selected light source equals a target light power. The light source is selected from the plurality of light sources on the basis of the light-emitting characteristic of each light source. The control unit controls, on the basis of the driving current of the selected light source, the driving currents of light sources which remain unselected in the plurality of light sources.

Abstract: An image forming apparatus includes an exposure unit, a developing unit and a transferring unit that transfers a visualized image of developer to an image recording medium. The exposure unit includes a light emitting unit, a detecting unit that detects a quantity of light, a reference voltage generating portion that generates a reference voltage set in accordance with a targeted value of the quantity of light, an emitted-light quantity control circuit that controls the quantity of light emitted from the light emitting unit so that a detection voltage becomes equal to a value of the reference voltage, and a reference voltage control portion that controls the reference voltage generating portion so as to change the reference voltage at a predetermined rate in stages. A new reference voltage is based on a density of the image of the developer obtained after being changed when the density is changed.

Abstract: In an exposure apparatus employing an over filled optical system, the light quantity distribution on a scanning plane is kept nearly constant for a plurality of scanning light quantities. It selects the light quantity of the light beam irradiated onto the photosensitive body from a plurality of levels, and sets the light quantity selected. According to the light quantity, it selects one of a plurality of correction current profiles, and supplies a light source with a current passing through the correction based on the correction current profile selected. Since the light quantity of the light beam irradiated onto the photosensitive body is corrected by the correction current, the light quantity of the light beam on the photosensitive body becomes nearly constant in the scanning direction.

Abstract: An adjustment quantity required for adjusting a quantity of light emission is computed based on an image density calculated from a measured quantity of light emission and sensitivity characteristics of an exposed photosensitive material to be exposed so that the image density of each of the light emitting devices within a device row becomes substantially equal to each other and the quantity of the light emission is adjusted based on the computed adjustment quantity.

Abstract: An image exposing apparatus forms an image on photosensitive material by the technique of exposing and forming an image through direct modulation of a semiconductor laser device. The exposing apparatus includes a beam scanning unit for scanning a beam emitted from a semiconductor laser device to photosensitive material, a laser driving unit for driving the semiconductor laser device, the laser driving unit being operable to vary its driving current to the semiconductor laser device in accordance with a received image signal, and a laser output controller operable to measure current-beam output characteristics of the semiconductor laser device over a predetermined current range and then set a correlation between the image signal for the laser driving unit and the driving current for the semiconductor laser device, based on the measurement information.

Abstract: The invention concerns an image recording apparatus suitable for forming a medical image that is used for a medical diagnosis, and a test pattern for evaluating a quality of the medical image. The image recording apparatus includes a printing section to either the medical image or the test pattern on the recording medium, based on image date; a printing-condition setting section to set a printing condition for printing the test pattern; and a printing-condition displaying section to display the printing condition set by the printing-condition setting section. The printing section prints at least one of a sharpness-evaluating pattern and a granularity-evaluating pattern.

Abstract: The image recording apparatus scans a heat mode recording material with a light beam modulated in accordance with image information, to thereby record an image on the heat mode recording material. The apparatus includes an unit for generating a modulated signal, an unit for generating an additional signal at a timing of at least one of rising and falling of the modulated signal and a unit for generating a drive signal by adding the additional signal to the modulated. The image forming method and apparatus scan a photosensitive material with the light beam to record an image, and a power of the light beam is set to a power of a level at which a recording line width or a recording dot size, which is determined depending upon a threshold value for the photosensitive material to blacken, is substantially fixed even if defocus occurs.

Abstract: An image quality detecting apparatus detects image quality based on a specified image pattern formed on an image carrier. This apparatus includes a light-emitting device that radiates a spotlight on the image carrier, a lens, a scanning unit that scans the image pattern with the spotlight, and a photoelectric conversion element that detects a quantity of light reflected from the image pattern and the image carrier or light transmitted through the image pattern and the image carrier during the scanning. The image quality is detected by setting a diameter of the spotlight at least in a scanning direction to the reciprocal number of a spatial frequency or smaller in which human eyesight is the most sensitive, for example, to 1000 ?m or less.

Abstract: An exposure apparatus for exposing a substrate to a light pulse via a mask. The apparatus includes an array of photoelectric converters to detect the light pulse, and a read circuit to read electrical signals from the array. The read circuit reads electrical signals from a part of the photoelectric converters sequentially switched with respect to each time interval between a successive two of the light pulses thereby to obtain cumulative electrical signals corresponding to a plurality of the light pulses.

Abstract: An image forming device employs a multi-laser beam system in which the light intensity of the second semiconductor laser is adjusted while simultaneously emitting laser beams from both the first and second semiconductor lasers. This configuration makes it possible to reduce the number of change-over circuits indispensable for line APC control of semiconductor lasers by one. Thus the maximum voltage stored in the second peak hold circuit is the voltage generated to light the first semiconductor laser and the second semiconductor laser simultaneously. The voltage generated to light the first semiconductor laser and the second semiconductor laser simultaneously is inevitably larger than the voltage generated to light only the semiconductor laser. For this reason, the second peak hold circuit does not require a separate change-over circuit to switch the circuit from the sampling state to hold state since the voltage stored in the second peak hold circuit is not updated when only the first semiconductor lights.

Abstract: In an image exposing apparatus and an image exposing method, a deterioration of an image quality caused by stray light is suppressed, while both a sensitive level and a non-sensitive level are properly set in accordance with a type of photosensitive material. In the image exposing apparatus, a recording level setting unit calculates a recording level corresponding to a light amount level stored in a recording level light amount memory and sets the calculated recording level. A non-recording level setting unit calculates a non-recording level from an extinction ratio, which corresponds to a type of photosensitive material stored in a photosensitive material information memory, and the recording level. An output voltage setting unit sets an output voltage such that a detected voltage becomes equal to one of the recording level and the non-recording level.

Abstract: In an optical recording apparatus, a detecting section detects disk identification information of an optical disk for selecting a constant which relates to the detected disk identification information. A test OPC section performs test writing operation for OPC at a predetermined linear velocity prior to recording of data so as to obtain a test value. A formulating section formulates an equation expressing a target value in function of a recording linear velocity based on the constant, the predetermined linear velocity and the test value. A running OPC section performs running operation of OPC by monitoring an actual value while irradiating a laser beam for the recording of data at the recording linear velocity. A controlling section controls the power of the laser beam such that the monitored actual value coincides with the target value which is determined by the equation with respect to the recording linear velocity.

Abstract: The present invention uses an open loop feedback technique to control emissive pixels of a printhead of a printer. The open loop feedback technique involves integrating the light intensity of the emissive pixel over a predetermined period of time, averaging the integrated value, comparing the averaged value to a threshold value, and adjusting the input voltage to the OLED of the pixel based on the comparison.

Abstract: According to an aspect of the present invention, a light beam scanning apparatus comprises light emitting unit for emitting a light beam, scanning control unit for controlling scanning of the light beam, light quantity detecting unit for detecting the quantity of light in the light beam, light quantity control signal output unit for outputting a light quantity control signal that performs control such that the quantity of light in the light beam is kept fixed on the basis of a result of detection of the quantity of light in the light beam, and light emission control unit for controlling a light emission timing for the light beam on the basis of image data and controlling the quantity of light in the light beam on the basis of the light quantity control signal while the light emission timing is being controlled.

Abstract: An image processing apparatus, comprising: an exposing device for exposing an image forming material so as to form a latent image on the image forming material based on image data; a thermal developing device for developing and visualizing the latent image on the exposed image forming material so as to form an image; a measuring device for measuring the image density of the image on the developed image forming material; a calibrating device for forming a table to define a relation between an image signal and image density on the basis of plural different test image data and measured-image densities thereof; a counting device for counting the number of the image forming material developed within predetermined time; and a controlling device for controlling the exposing device, the thermal developing device, the measuring device, the calibrating device and the counting device; wherein the controlling device stop forming the table for predetermined time when the counting device counts the number of the developed

Abstract: There is described an image-forming apparatus, which can prevent unevenness of an image by controlling the brightness of light-sources. The apparatus includes a light source, including a plurality of light-emitting elements aligned within a predetermined width; an exposure-controlling section to individually control each of intensities of light beams emitted by the plurality of light-emitting elements; and a memory section to store light-intensity compensation data for each of the plurality of light-emitting elements. The image is formed by simultaneously exposing the light beams aligned within the predetermined width onto the photosensitive recording medium, and the exposure-controlling section controls each of the plurality of light-emitting elements based on the light-intensity compensation data concerned, so that each of intensities of the light beams substantially coincides with each of target intensities set in advance.

Abstract: An exposure apparatus reads an electrical signal from a photoelectric sensor by using the time interval between emission pulses even at a high emission frequency of the light source. A photoelectric sensor attached to an exposure apparatus which exposes a substrate to a pulse beam emitted by a light source for generating a pulse beam has a plurality of photoelectric converters. The photoelectric converters are divided into a plurality of blocks. While charges are read from each block by using one time interval between pulse beams, charges in all the photoelectric converters are read by using a plurality of time intervals between pulse beams.

Abstract: With a control device to optimize charge image generation in an electrophotographic process, a light-sensitive and temperature-sensitive photoconductor layer is exposed pixel-by-pixel with a temperature-sensitive light source. The photoconductor layer becomes more sensitive with rising temperature, such that given a predetermined light quantity it discharges deeper. With rising temperature, given the same actuating power, the light source emits a lesser luminous power. The luminous power of the light source and the discharge depth of the photoconductor layer are temperature-dependent via adjustment of the current and/or the luminous duration that flows through the light source and/or the luminous duration. During the measurement of the discharge depth, a temperature measured in the course of the measurement event is used as a reference value for the temperature compensation of the light source.

Abstract: There is provided an emission control apparatus with which it is capable of variably controlling the intensity of a light beam to be set, in a stable manner and at a low cost without increasing the circuit size. A semiconductor laser diode LD emits a light beam. A photo diode PD detects the intensity of the light beam emitted from the semiconductor laser diode LD. A driving circuit supplies driving current to the semiconductor laser diode LD. A switching section switches the driving current according to a video signal. An input terminal receives a pulse width modulation signal. A smoothing circuit smoothes the received pulse width modulation signal. A laser driver controls a value of the driving current according to smoothed voltage obtained by the smoothing circuit such that the detected intensity of the light beam is equal to a target intensity.

Abstract: An image quality detecting apparatus detects image quality based on a specified image pattern formed on an image carrier. This apparatus includes a light-emitting device that radiates a spotlight on the image carrier, a lens, a scanning unit that scans the image pattern with the spotlight, and a photoelectric conversion element that detects a quantity of light reflected from the image pattern and the image carrier or light transmitted through the image pattern and the image carrier during the scanning. The image quality is detected by setting a diameter of the spotlight at least in a scanning direction to the reciprocal number of a spatial frequency or smaller in which human eyesight is the most sensitive, for example, to 1000 ?m or less.

Abstract: A movable light beam is controlled and set within a tolerable range of a beam position A by using a galvano-mirror, and then a circuit offset relating to the beam position A is measured. With the circuit offset being subtracted, the movable laser beam is exactly controlled and set at the beam position A, and an output value DA from a sensor at that time is stored. Subsequently, an output value DB from the sensor is similarly stored in connection with a beam position B. An ultimate beam position of the movable laser beam M is controlled such that a difference between the output values DA and DB coincides with a difference between an output value DS of the sensor with respect to a stationary laser beam S and an output value DM of the sensor in connection with the movable laser beam M.

Abstract: A method of adjusting the maximum intensity of a laser exposure mechanism for irradiating laser light to the surface of a photoreceptor to which a uniform potential is being given by a corona discharger. Photoreceptor surface portions are exposed to laser lights of a plurality of laser intensities obtained by coarsely dividing an optional laser intensity, and the potentials of the photoreceptor surface portions are detected (coarse-division potential detecting step). In the vicinity of the laser intensity corresponding to the potential closest to the desired preset potential, the predetermined laser intensity is further finely divided to set a plurality of laser intensities, photoreceptor surface portions are exposed to laser lights of the plurality of laser intensities thus set, and the potentials of the photoreceptor surface portions are detected (fine-division potential detecting step).

Abstract: A linefeed calibration method for identifying media advancement errors utilizes plural test patterns, including both a base pattern and an overlay pattern that are printed overlying each other to form an interference pattern. A sensor detects overall alignment of the interference pattern. That overall alignment is compared to alignment of at least a second interference pattern to identify a linefeed advance error. The error is correlated to a position on a media advancement mechanism such as a roller. A processor then adjusts the media advancement mechanism to correct the identified media advancement error. Under-advance errors, over-advance errors and skew errors may be identified using the described method.

Abstract: A method of reducing consumption of a developer used in an electrophotographic processor that forms a latent electrostatic image on a charged photosensitive object using a laser exposure unit for outputting a laser beam, the method including adjusting a power of the laser beam to match a user-selected density of an output image so as to adjust an electric potential between an image region and a non-image region of the latent electrostatic image, wherein the consumption of the developer is reduced, and an electrophotographic processor performing the method.

Abstract: If an abnormal current is applied to a laser diode at the rise time and fall time of a power voltage, a laser diode's life may be shortened. In a laser diode drive, circuits monitoring a current voltage are set up in two systems. At the same time, the monitor voltage of one system that controls the on/off operation of the internal bias voltage is set high relative to a monitor voltage of the other system controlling an output current; until the internal bias voltage becomes stable when power is on and before the internal bias voltage cuts off and makes the circuit operation unstable when power is off, by giving another reference voltage in lieu of a reference voltage as the reference voltage of the voltage-current conversion circuit, the output status of the voltage-current conversion circuit is controlled in the direction of decreasing a current that is applied to the laser diode, so that the laser diode is prevented from receiving an abnormal current at the rise time of the power voltage.

Abstract: An electrophotographic device with a laser power correction device (and method therefor) includes a laser power detection sensor retractably disposed relative to a laser beam optical path of a laser beam, a laser power adjusting device for controlling laser power of the laser beam based on an output from the laser power detection sensor, and a controller for inserting the laser power detection sensor into the optical path and applying laser power correction when a total laser beam activation time has reached a predetermined time and printing is stopped.

Abstract: In a digital copying machine using a multi-beam optical system, a sensor pattern senses a light beam directed onto the photosensitive drum and generates current according to the amount of light. The current is converted into a voltage by an operational amplifier acting as a current/voltage conversion amplifier. The output voltage of the operational amplifier is integrated by an integrator. The output of the integrator is converted into a digital signal by an A/D converter, thereby producing luminous energy sensing information. According to the luminous energy sensing information, a laser oscillator is controlled. Between the operational amplifier and integrator, a variable resistor is inserted which absorbs variations in the sensitivity of the sensor pattern or variations in the conversion characteristic of the operational amplifier.

Abstract: In a photographic printer using a laser scanning unit for exposing a latent image corresponding to an image data on a sensitized surface of a photographic paper, intensities of the laser beams exposing the photographic paper are adjusted corresponding to a variation of an actual sensitivity of the photographic paper and deterioration of a developer with respect to nominal values of them. At least the intensities directly emitted from laser light sources, or values of optical modulation data for modulating the laser beams corresponding to the image data are varied. Alternatively, transmittances of optical elements such as polarizing beam splitters provided on optical paths are varied for adjusting the intensities of the laser beams.

Abstract: An image forming apparatus for forming an image by irradiating a charged surface of a photosensitive member with a laser beam depending on a picture signal to form an electrostatic latent image, visualizing the latent image with a recording agent, and transferring the visualized image onto a recording medium; includes a circumferential position detection unit for detecting a circumferential position of the photosensitive member irradiated with the laser beam and an APC circuit for controlling a light quantity of the laser beam so as to provide a target light quantity varying depending on the detected circumferential position.

Abstract: An exposure head is provided in which light beams from light emitting parts 63 pass through a transparent substrate 62 and are projected on an image carrier. The transparent substrate 62 has plain faces substantially parallel to each other, one of the faces being a face on which the light emitting parts 63 are formed and the other being a face from which light beams are projected. The transparent substrate 62 is provided, at position(s) other than the face on which the light emitting parts 63 are formed and than the face from which light beams are projected, with light quantity detecting means 100 for detecting the quantity of light emitted from said light emitting parts 63.

Abstract: A torsion oscillator (FIG. 1) is stabilized in operation by determining the current resonant frequency (62); in a first procedure, observing the oscillator for change in resonant frequency (64), and then restoring the amplitude and median offset (66) without changing the drive frequency. In an alternative procedure, after determining the resonant frequency (62); setting the drive frequency close to but offset from the current resonant frequency (74), observing the oscillator for change in resonant frequency (76), and the restoring the close offset to the changed resonant frequency (78). By operating slightly off peak, the direction of resonant change is immediately known. The first procedure has less difficulties in implementation, but requires more power.

Abstract: A laser drawing apparatus according to the invention calibrates the accuracy of a first light quantity monitor in detecting the quantities of laser beams, based on results of detection by a second light quantity monitor of the quantities of laser beams emitted from an imaging optical system to a drawing stage, when a characteristic deterioration of or adhesion of foreign matter to optical components of the first light quantity monitor has resulted in variations in the optical characteristic of the first light quantity monitor, and variations in the detection by the first light quantity monitor of the quantities of the laser beams. The quantities of the laser beams emitted to a printed circuit board (image-receiving object) is thereby adjusted to a proper value, to maintain high-quality, high-definition drawings requiring a high degree of light quantity precision.

Abstract: A power controller is provided which can control the emission power from a light source to follow an appropriate response property based on a target value. The power controller includes feedforward systems for allowing currents corresponding to target values set at target value setting units to be switched at a switching device and supplied as a power setting current to an adder. Also included are feedback systems for detecting the power of the laser beam emitted by a semiconductor laser serving as the light source and adjusting a feedback current to stabilize the deviation from the target values at a predetermined value. Further included are a switching device for allowing the target values to be switched and supplied to the aforementioned feedback systems, and the adder for adding a feedback current and the power setting current to thereby generate a drive current for driving the semiconductor laser.

Abstract: An image forming apparatus for forming an image by modulating laser light in correspondence with an image signal. A pulsewidth modulation signal is generated in correspondence with input image data. A laser drive control circuit has a photosensor PD which detects laser light emitted from a laser diode LD and generates a detection current, a resistor which generates a detection voltage corresponding to the detection current outputted from the photosensor PD, a buffer in which the generated detection voltage is inputted, an amplifier which amplifies an output from the buffer, and a constant current source and a switch to add a predetermined current to the detection current for compensation for reduction of output voltage due to offset voltages of the buffer and the amplifier. Control data for controlling maximum and minimum pulsewidths in the pulsewidth modulation signal are obtained based on the detection voltage, and generation of the pulsewidth modulation signal is controlled.

Abstract: When a light beam scans a scanned surface in a horizontal scan direction, a sensor is arranged on the scanned surface or a position equivalent to the scanned surface. The sensor converts a light quantity of the light beam into an electric signal to be output. The light beam's passage position is gradually moved in a vertical scan direction to detect a maximum value of the electric signal output from the sensor. When the detected maximum value is smaller than a specified reference value, the light beam is determined to be defocused.

Abstract: An image forming apparatus includes a light emitting array composed of a plurality of light emitting elements that emits light fluxes. An imaging element array may be provided so as to perform imaging with the light fluxes on a prescribed plane. A three dimensional exposure intensity distribution of the light flux is obtained per each light emitting element. A prescribed attribute is obtained from each of the exposure intensity distributions. A plurality of comparison values for the entire exposure valid region may be obtained from different units which consist of two or more successive attributes. Prescribed light emitting quantities enabling all of the comparison values to fall within a prescribed range may be determined and set to respective light emitting elements.

Abstract: In a laser beam scanner of used for exposing a latent image on a photographic paper, intensities of the laser beams are maintained in predetermined range by compensating amplitude of driving signals supplied to acousto-optic modulators when intensities of the laser beams emitted from laser light sources are varied. The intensities of the laser beams passing through the modulators are sensed by photo sensors and compared with predetermined standard value. When any of the intensity of the laser beam is discrepant from the standard value, a difference between them is calculated and an optical modulation data for controlling the amplitude of the driving signal is compensated by subtracting the difference value from the standard value. Thereby, the amplitude of the driving signal of the modulator is compensated.

Abstract: An electric photograph system for improving non-linearities of an exposing light intensity and an operating current at a low exposing level when performing analog printing operation. A range (saturable absorber) having a saturable absorbing characteristic is provided in a part of an optical path including a semiconductor laser as light source to improve the non-linearity of the operating current when the light intensity is weak. The saturable absorber may be made in the form of a non current injected area provided in a part of the semiconductor laser as the light source or a thin film layer provided partly in films coated on a facet of the semiconductor laser. Due to the provision of the saturable absorber, the light output power characteristic can exhibit its linearity in its low optical power range, the size of a printing dot can be arithmetically changed, and thus fine laser printing can be realized.

Abstract: In order to expose a required exposed line for which an exposing deviation caused by a fixing accuracy of an exposing head is corrected, when exposing images by dynamic lighting control, an image forming apparatus comprises a exposing head 24 having a plurality of arrayed illuminants aligned in the main scanning direction wherein, when an image bearing body moving in the auxiliary direction at a predetermined scanning speed is exposed to form an image by controlling dynamically to light arrayed illuminants according to image data, a detector for a position of a print head 17 detects a deviation from a predetermined standard fixing point generating a deviating position detecting signal. A memory control circuit 14 selects as an exposing data from image data of the k−1 (k is an integer greater than 1) precedent line to image data of the current line based on a correcting value determined in accordance with a deviation denoted by the position-detecting signal.

Abstract: Calibration of the light emitting elements in an optical printer is carried out by mounting the optical printer on an external monitoring apparatus. The external monitoring apparatus comprises: a sensor mounting portion whereon a plurality of photosensors are mounted in a straight line; a signal processing circuit for processing the signals output from the photosensors; a reference voltage generating circuit; and a comparison and control circuit for comparing the output from the signal processing circuit with the reference voltage from the reference voltage generating circuit and outputting a signal based on the results of the comparison. The photosensors receive the light output from the light emitting elements, being subject to calibration, in the optical printer.

Abstract: A calibration system is disclosed for use with an imaging system including a laser line illumination source. The calibration system includes an imaging head, a mask having a calibration opening through which a portion of the line of laser illumination may pass, and a calibration unit. The imaging head is movable along a slow scan direction with respect to an imaging surface for imaging a line of laser illumination in the slow scan direction. The calibration opening has a width in the slow scan direction that is larger than a full width half maximum distance of an imaging spot of a smallest addressable picture element of the line of laser illumination. The calibration unit is for receiving a portion of the line of laser illumination through the calibration opening and for processing the received portion of the line of laser illumination.

Abstract: In an image exposing apparatus and an image exposing method, a deterioration of an image quality caused by stray light is suppressed, while both a sensitive level and a non-sensitive level are properly set in accordance with a type of photosensitive material. In the image exposing apparatus, a recording level setting unit calculates a recording level corresponding to a light amount level stored in a recording level light amount memory and sets the calculated recording level. A non-recording level setting unit calculates a non-recording level from an extinction ratio, which corresponds to a type of photosensitive material stored in a photosensitive material information memory, and the recording level. An output voltage setting unit sets an output voltage such that a detected voltage becomes equal to one of the recording level and the non-recording level.

Abstract: A printer for printing on a recording medium with a plurality of processes includes a first processing section for making a first process on the recording media; a second processing section arranged close to the first processing section for making a second process different from the first process on the recording media on which the first process was made, thereby obtaining an image on a surface of the recording medium; and a recording medium feed path formed between the first processing section and the second processing section. The entire apparatus is made compact without decreasing a recording medium feeding performance and a printing process capability by that a plurality of processing units serving for the printing processes and recording medium feed path linking those units are arranged reasonably.

Abstract: An image forming apparatus for forming an image by irradiating a charged surface of a photosensitive member with a laser beam depending on a picture signal to form an electrostatic latent image, visualizing the latent image with a recording agent, and transferring the visualized image onto a recording medium; includes a circumferential position detection unit for detecting a circumferential position of the photosensitive member irradiated with the laser beam and an APC circuit for controlling a light quantity of the laser beam so as to provide a target light quantity varying depending on the detected circumferential position.

Abstract: A printer head for computer-to-plate printing includes a linear array of individually addressable diode-lasers and a linear array of photodetectors. The number and spacing of the photodetectors is the same as the number and spacing of the diode-lasers. The diode-lasers emit in forward and reverse directions. The diode-lasers and photodetectors are aligned parallel to each other such that reverse-emitted light output of each diode-laser is incident on a corresponding photodetector. Each photodetector output is monitored by a dedicated controller/driver sub-circuit that regulates drive current supplied to the diode-laser. The drive current is regulated according to a comparison of the monitored photodetector output with a reference current individually calibrated in each sub-circuit. Calibration data for each sub-circuit is obtained from a measurement of forward-emitted output power of its corresponding diode-laser compared with a desired target forward-emitted power.

Abstract: An exposure apparatus having a plasma light source and a shutter provided between the plasma light source and an initial-stage optical device of an illumination system. The shutter is closed, and light emission by the plasma light source is started prior to the start of exposure processing by a stabilization period. When the stabilization period has elapsed, the exposure processing including a shutter opening operation is started. The stabilization period is equal to or longer than time necessary for stabilization of light emission intensity of the plasma light source. The stabilization period is previously measured and stored into a memory of controller 102. This maintains a long life of multilayer film mirror, and prevents the fluctuations in EUV light emission intensity due to the temperature change of the light source and accompanying change of the size of fine pattern and degradation of resolution and the like, thus enables stable transfer of fine pattern.

Abstract: An electrophotographic device with a laser power correction device (and method therefor) includes a laser power detection sensor retractably disposed relative to a laser beam optical path of a laser beam, a laser power adjusting device for controlling laser power of the laser beam based on an output from the laser power detection sensor, and a controller for inserting the laser power detection sensor into the optical path and applying laser power correction when a total laser beam activation time has reached a predetermined time and printing is stopped.

Abstract: A laser drawing apparatus according to the invention calibrates the accuracy of a first light quantity monitor in detecting the quantities of laser beams, based on results of detection by a second light quantity monitor of the quantities of laser beams emitted from an imaging optical system to a drawing stage, when a characteristic deterioration of or adhesion of foreign matter to optical components of the first light quantity monitor has resulted in variations in the optical characteristic of the first light quantity monitor, and variations in the detection by the first light quantity monitor of the quantities of the laser beams. The quantities of the laser beams emitted to a printed circuit board (image-receiving object) is thereby adjusted to a proper value, to maintain high-quality, high-definition drawings requiring a high degree of light quantity precision.

Abstract: In an optical recording apparatus, a detecting section detects disk identification information of an optical disk for selecting a constant which relates to the detected disk identification information. A test OPC section performs test writing operation for OPC at a predetermined linear velocity prior to recording of data so as to obtain a test value. A formulating section formulates an equation expressing a target value in function of a recording linear velocity based on the constant, the predetermined linear velocity and the test value. A running OPC section performs running operation of OPC by monitoring an actual value while irradiating a laser beam for the recording of data at the recording linear velocity. A controlling section controls the power of the laser beam such that the monitored actual value coincides with the target value which is determined by the equation with respect to the recording linear velocity.