Abstract:
An optical PH includes: a plurality of current-driven light emitting elements that are arranged in a line-shaped region; a controller that outputs a control voltage instructing an amount of a drive current to be supplied to each of the light emitting elements; and a plurality of drivers that correspond one-to-one with the light emitting elements, and each supply the drive current to a corresponding one of the light emitting elements, wherein the drivers each operate as one of: a high-voltage referring driver that supplies the drive current according to a voltage difference between the control voltage and a reference voltage higher than the control voltage; and a low-voltage referring driver that supplies the drive current according to a voltage difference between the control voltage and a reference voltage lower than the control voltage.
Abstract:
An image forming device includes: element arrays each including light emitting elements arranged in main scanning direction, the arrays being arranged in sub scanning direction; a photoreceptor whose surface moves relative to the light emitting elements in the sub scanning direction; a controller outputting control voltage instructing light emission amount for each light emitting element; and drivers each supplying drive current to a corresponding light emitting element according to the control voltage, thus causing the light emitting element to emit light to expose the moving surface of the photoreceptor. Intervals L between the arrays satisfy (D/2)×(V/F)−((V/F)×0.1)≤L≤(D/2)×(V/F)+((V/F)×0.1) where F expresses frequency of AC noise to be superimposed on the control voltage, V expresses system speed of the surface of the photoreceptor moving relative to the light emitting elements, and D is an odd number.
Abstract:
An image forming device includes: element arrays each including light emitting elements arranged in main scanning direction, the arrays being arranged in sub scanning direction; a photoreceptor whose surface moves relative to the light emitting elements in the sub scanning direction; a controller outputting control voltage instructing light emission amount for each light emitting element; and drivers each supplying drive current to a corresponding light emitting element according to the control voltage, thus causing the light emitting element to emit light to expose the moving surface of the photoreceptor. Intervals L between the arrays satisfy (D/2)×(V/F)−((V/F)×0.1≤L≤(D/2)×(V/F)+((V/F)×0.1) where F expresses frequency of AC noise to be superimposed on the control voltage, V expresses system speed of the surface of the photoreceptor moving relative to the light emitting elements, and D is an odd number.
Abstract:
An optical print head for forming an electrostatic latent image on a photosensitive body, including: current-driven light-emitting elements disposed in a line shape; an indicator circuit that outputs indicator current indicating light emission amounts to the light-emitting elements; and for each light-emitting element: a holding circuit that, during a main scanning period, accumulates indicator current during a sample period to generate an indicator potential and holds the indicator potential during a hold period; and a drive circuit that supplies drive current to the light-emitting element according to the indicator potential, wherein each of the sample periods is divided into writing periods, and each of the holding circuits holds the indicator potential corresponding to the holding circuit according to a total of indicator current amounts in the sample period corresponding to the holding circuit, the indicator current amounts each indicative of indicator current during one of the writing periods.
Abstract:
An optical print head performs optical writing onto target, and includes: current-driven light-emitting elements arranged in rows in a predetermined direction; driving transistors that are each electrically series-connected with the light-emitting elements in one-to-one correspondence, and each supply a driving current to a corresponding light-emitting element; a current control unit that controls, for each light-emitting element, a driving current amount in accordance with variation in light-emitting properties of the light-emitting element that indicate relation between the driving current amount and a light amount emitted by the light-emitting element; an application unit that, upon receiving electrical power supplied from an external power source, applies application voltage to circuits each consisting of a light-emitting element and a corresponding driving transistor; and a voltage control unit that suppresses variation in divided voltage applied to each driving transistor by controlling the application unit to apply increased application voltage of the driving current amount increases.
Abstract:
An optical writing device having; a plurality of light-emitting points; a plurality of drive circuits for supplying drive currents to the plurality of light-emitting points respectively; a photodetector for outputting signals indicating quantities of light entering thereto from the respective light-emitting points; a gain switch circuit for outputting photodetection signals obtained by amplifying the signals output from the photodetector in regard to the respective light-emitting points with gains preset for the respective light-emitting points; and a control circuit for controlling the drive circuits such that the photodetection signals output from the gain switch circuit in regard to the respective light-emitting points coincide with a value substantially equal to a predetermined reference value. The gains for the respective light-emitting points are preset based on the distances between the photodetector and the respective light-emitting points.
Abstract:
An optical writing device for forming an electrostatic latent image on a photoreceptor by exposing the photoreceptor to light modulated in accordance with image data. The optical writing device has: a substrate; a light-emitting-element array including a plurality of light-emitting elements supported by the substrate to be arranged in a main-scanning direction; and a light-receiving-element array substantially in parallel to the light-emitting-element array, the light-receiving-element array including a plurality of light-receiving elements supported by the substrate to be arranged in the main-scanning direction. For light-quantity measurement of one of the light-emitting elements, at least an output value output from one of the light-receiving elements of which center is located in a different position, with respect to the main-scanning direction, from a center of the one of the light-emitting elements is used.
Abstract:
An optical writing device having; a plurality of light-emitting points; a photodiode configured to output a signal which represents a quantity of incident light from a predetermined light-emitting point selected from the plurality of light-emitting points; and a calculation section for calculating a temperature of the photodiode based on a magnitude of a photodiode dark current included in the signal output from the photodiode while the predetermined light-emitting point is OFF.