Ricoh Company, Ltd.

Hidetoshi Yamashita

Naoto Watanabe

Nobuyoshi Kaima

Norihiro Yamamoto

Tatsuo Ohyama

Yumiko Kishi

Toshio Ohide

An optical device includes: a light source including a plurality of light emitting spots that output laser beams, respectively; a separating unit that separates each of the laser beams output from the plurality of light emitting spots into a monitor beam and a scanning beam; a light-quantity measuring unit that measures a light quantity of the monitor beam; a storage unit in which respective drive currents with which the plurality of light emitting spots of the light source output a prescribed light quantity of laser beams are stored in advance; a light-source control unit that drives the light source with the drive currents stored in the storage unit and causes the plurality of light emitting spots to output the laser beams; and a determining unit that determines whether the light source operates properly on the basis of the light quantity measured by the light-quantity measuring unit.

Optical device, control method for the same, and image forming apparatus

An optical device includes: an irradiation unit that irradiates a part of laser beams output from a light source as a scan beam onto an irradiation target and outputs the remaining part of the laser beams as a monitor beam used to monitor a light amount of the laser beams; a measurement unit that measures a light amount of the monitor beam; a storage unit that stores a plurality of measurement results obtained by the measurement unit when the laser beams are output in a plurality of different light amounts, and the plurality of the different light amounts associated with each other; and a prediction unit that predicts the light amount of the monitor beam relative to a reference light amount of the laser beam using a plurality of the light amounts stored in the storage unit and the measurement results corresponding to the plurality of the light amounts.

Optical device, control method of optical device, and image forming apparatus

An optical device includes a drive unit configured to drive a light source that outputs a laser beam; a detecting unit configured to detect the laser beam output from the light source; a converting unit configured to convert an output of the detecting unit into a value within a predetermined range; and a control unit configured to control the drive unit to switch a light quantity of the laser beam output from the light source from a first light quantity within an imaging light quantity range for forming an image to a second light quantity outside the imaging light quantity range, or vice versa. The converting unit converts an upper limit light quantity in the imaging light quantity range into a maximum value in the predetermined range, and converts a lower limit light quantity in the imaging light quantity range into a minimum value in the predetermined range.

Optical device, image forming apparatus, and method for controlling optical device

An optical device includes: a light source that emits laser beams; a detecting unit that detects the laser beams and converts light amounts of the detected laser beams into voltage values; a first storage unit that stores in advance a light amount to be output for each of the laser beams and the voltage value; a second storage unit that stores in advance a value indicating light use efficiency of an optical system that guides the laser beams to a surface to be scanned for scanning; a calculating unit that calculates a target voltage value for each of the laser beams based on the light amount and the voltage value and also on the value indicating the light use efficiency; and a control unit that controls emission power for each of the laser beams so that the voltage value output from the detecting unit approaches the target voltage value.

Optical device and method for controlling the same

An image forming apparatus includes a light source that outputs a plurality of laser beams and a control unit that adjusts the light intensity of each of the laser beams. The control unit calculates a correction value so that, when the laser beam is driven by a control value calculated by correcting a common control value using the correction value and adding a threshold to the corrected control value, the light intensity of the laser beam is equal to a target light intensity. The threshold is calculated so that, when the laser beam is driven by a control value calculated by multiplying the corrected control value by a predetermined factor, and adding the threshold to the multiplied control value, the light intensity of the laser beam is equal to the target light intensity multiplied by the predetermined factor.

Image forming apparatus and light intensity control method

An optical writing device includes a light source that emits multiple laser beams; a separating unit that separates each of the multiple laser beams into a monitor beam and a scanning beam; a photoelectric converting elementthat outputs a monitor voltage depending on a quantity of the monitor beam; a memory that stores an initial correction value for correcting a set common current; and a microcontroller that calculates a reference current, which is produced by correcting the common current updated on the basis of the monitor voltages with the initial correction values, obtains corrected currents by correcting the common current with the calculated correction values, controls each quantity of the laser beam on the basis of the corrected currents, and determines that the light source is degraded if a ratio of the corrected current to the reference current is larger than a predetermined threshold value.

Optical writing device and optical writing method

An image forming apparatus includes a light source; a separating unit that separates a laser beam emitted from the light source into a first laser beam and a second laser beam; a first photoelectric converting unit that measures a light intensity of the first laser beam and outputs a first voltage depending on the light intensity of the first laser beam; a second photoelectric converting unit that measures a light intensity of the second laser beam, and outputs a second voltage depending on the light intensity of the second laser beam; and a control unit that executes a first light-intensity correction for correcting the light intensity of the second laser beam based on a current correction value and a drive current. The current correction value being a value used for correcting a light intensity of the laser beam based on the first voltage and the second voltage, and the drive current being a current preliminarily-set with respect to the laser beam to cause the light source to emit the laser beam.

Method and apparatus for forming image

A first beam splitter splits each laser beam into a first beam and a second beam. A deflecting unit deflects a direction of the second beam. A second beam splitter splits the second beam into multiple split beams. A first photoelectric converting unit measures intensity of the first beam and outputs first voltage. A second photoelectric converting unit measures intensity of each split beam and outputs second voltage. A control unit updates a driving-current correction value using the first voltage and the second voltage, corrects a driving current, and controls intensity of the laser beam based on corrected driving current.

Multibeam image forming

An image forming apparatus includes a light source that emits a laser beam, a separating unit that separates the laser beam emitted from the light source into a first laser beam, and a second laser beam. a first photoelectric converting unit, a second photoelectric converting unit, and a control unit that executes a first light-intensity correction for correcting the light intensity of the second laser beam per scan by each scanning line, and a second light-intensity correction for adjusting a performance in forming the image data based on a current correction value for correcting a light intensity of the laser beam based on a first voltage and a second voltage and a drive current preliminarily-set with respect to the laser beam to cause the light source to emit the laser beam.

In an image forming apparatus, a separating unit separates each laser beam into a first laser beam used for measuring light intensity and a second laser beam used for scanning a photosensitive element, a photoelectric converting unit measures a light intensity of each of the first laser beams and outputs a voltage indicative of the light intensity. A control unit controls a light intensity of each of the laser beams based on a common drive current and a corresponding one of a current correction value, which is set by each of the laser beams to correct a light intensity of a corresponding one of the laser beams based on a corresponding one of the voltages output by the photoelectric converting unit.

A novel image processing system includes a pixel position indicator and a pixel inserting unit. The pixel position indicator is configured to indicate insertion positions in the image data. The pixel inserting unit is configured to enlarge a size of the image data by inserting an additional pixel at each of the insertion positions and accordingly shifting the original pixels in a given direction. The additional pixel has a value lower than a given threshold. Each insertion position is at an approximate center of an area formed of pixels having values higher than the given threshold. A novel image forming apparatus incorporates such an image processing system and an electrophotographic system. The electrophotographic system is configured to form an image by irradiating a photoconductive surface with a laser beam according to the processed image data.

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Kanagawa, Japan

Hidetoshi Yamashita