Abstract: An image forming apparatus includes: a density detection unit that detects densities of an image developed by a developing unit at a plurality of positions in a main-scanning direction; a processing unit that obtains at least one of an amplitude and a phase of a first periodical density change of the image, of which cycle is a rotation cycle of a photosensitive drum, at the plurality of positions in the main-scanning direction on the basis of an output signal of the density detection unit, and corrects a drive signal for the light source so as to suppress the first periodical density change of the image at each position in the main-scanning direction on the basis of the rotation cycle of the photosensitive drum and at least one of the amplitude and the phase.

Abstract: A light source driver includes a controller which outputs an undershoot current in synchronization with lighting complete timing in lighting information, wherein the controller is configured to output the undershoot current such that a voltage in a light source when the output of the undershoot current is complete is equal to a voltage in the light source before being turned on.

Abstract: A light source driving circuit that drives a light source includes a driving electric current generator that generates a driving electric current including a predetermined electric current, a first auxiliary current, and a second auxiliary current; and a controller that sets values of the first and second auxiliary currents by using first and second lighting pattern signals, wherein each of the first and second lighting pattern signals is for controlling supply of the predetermined electric current to the light source. After setting a first value of the first auxiliary current, a second value of the second auxiliary current is set by using the second lighting pattern signal that defines a time period for stopping supply of the predetermined electric current to be shorter than a time period for stopping the supply of the predetermined electric current that is defined by the first lighting pattern signal.

Abstract: A laser driving unit drives a semiconductor laser apparatus including a plurality of light sources, includes a light detecting part to detect light emissions from the light sources, a driving current generator to generate a driving current based on an input signal, an auxiliary driving current generator to generate an auxiliary driving current in an initial time period of an ON-time of the driving current, and an auxiliary current set part to set an auxiliary amount of the auxiliary driving current to be added to the driving current, for each of the light sources, based on a difference between the light emissions detected by the light detecting part and a target light emission of the light sources.

Abstract: An image forming apparatus includes: a pseudo-halftone processing unit that processes input image data to output image data of first resolution; a resolution converting unit that converts the image data of the first resolution into image data of second resolution that is higher than the first resolution; a modulation-signal generating unit that generates a modulation signal obtained by modulating the image data of the second resolution according to a clock signal; and a light-source driving unit that drives a light source according to the modulation signal. The pseudo-halftone processing unit converts a region of pixels having the same pixel value into a parallel line pattern that is formed with a plurality of parallel lines oblique relative to a direction of arrangement of pixels. The resolution converting unit generates the image data o in which each edge of the lines forming the parallel line pattern is smoothed.

Abstract: An image forming apparatus for forming an image in accordance with light to be emitted from a light source includes: a digital half-toning unit configured to convert a uniform-pixel-value region of image data to a parallel-line pattern formed with a plurality of parallel lines extending obliquely with respect to a direction, in which pixels are arrayed, thereby expressing each gray level of the image data as an area percentage; a modulated-signal generating unit configured to generate a modulated signal by modulating the converted image data with a clock signal; a light-source driving unit configured to drive the light source according to the modulated signal; and an edge control unit configured to narrow a to-be-illuminated region, which is to be illuminated by the light from the light source, in each of edge neighborhoods of the lines constituting the parallel-line pattern, while increasing intensity of the light.

Abstract: An image forming apparatus forms an image by irradiating light from a light source to an image carrier. The image forming apparatus includes: an image processing unit that processes image data at resolution N; and a control unit that generates modulation data to drive the light source at resolution m×N (m is a positive integer equal to or larger than 2), which is higher than the resolution N, based on the processed image data. Processing at the image processing unit is pseudo-halftone processing to perform line thinning or thickening on a part of the image data. The control unit converts the image data at the resolution N that has been subjected to the pseudo-halftone processing into data at the resolution m×N, and adjusts an amount of light for a part of the image data based on the resolution m×N.

Abstract: An image forming apparatus that forms an image according to light emitted from a light source is provided. The image forming apparatus includes: a first image processor that performs image processing on image data having a first resolution and outputs the resulting image data; a resolution converter that acquires the image data having the first resolution output from the first image processor and converts the image data to image data having a second resolution that is higher than the first resolution; a modulation signal generator that modulates the image data having the second resolution according to a clock signal to thereby generate a modulation signal; a light source driver that drives the light source according to the modulation signal; and a second image processor that performs image processing on the image data having the second resolution to be modulated to the modulation signal.

Abstract: A laser driving device that drives a semiconductor laser based on a light-emitting signal includes an expansion circuit that expands a pulse width of the light-emitting signal based on a known difference between the pulse width of the light-emitting signal and a lighting pulse width of the semiconductor laser when the semiconductor laser emits light according to the light-emitting signal, and a driver that outputs a driving signal to the semiconductor laser according to an output signal of the expansion circuit.

Abstract: A light source driver includes a controller which outputs an undershoot current in synchronization with lighting complete timing in lighting information, wherein the controller is configured to output the undershoot current such that a voltage in a light source when the output of the undershoot current is complete is equal to a voltage in the light source before being turned on.

Abstract: A light source drive circuit for driving a light source is disclosed including a drive current generating unit generating a drive current, the drive current including a predetermined current for obtaining a predetermined light amount from the light source, a first auxiliary current input to the light source prior to input of the predetermined current, and a second auxiliary current added to the predetermined current in synchronization thereto; and a signal generating unit generating a first signal and a second signal, the first signal causing the first auxiliary current to be input for a first period and the second signal causing the second auxiliary current to be applied to the predetermined current for a second period. The first period is shorter than a period from a rise of the predetermined current to when a light amount from the light source reaches the predetermined light amount with the predetermined current.

Abstract: A light source drive circuit which drives a light source is disclosed, including a drive current generating unit which generates a drive current, the driving current including a predetermined current for obtaining a predetermined light amount from the light source; and first and second overshoot currents which are applied to the predetermined current in synchronization thereto; and a control unit which sets, to the drive current generating unit, a value of the first overshoot current to a fixed value, and a value of the second overshoot current in accordance with a light amount output from the light source.

Abstract: A light source driver mounted on a rectangular-shaped substrate includes a plurality of output parts that output driving signals to drive a plurality of light-emitting bodies. The plurality of output parts are disposed in a vicinity of the two sides of the substrate, the two sides of the substrate forming a corner of the substrate.

Abstract: Apparatus that forms an image according to image information includes density sensors that detect image density variations in main and sub-scanning directions. A processing device generates correction data for correcting a light source output to suppress the density variations based on detection results. The processing device modifies the correction data such that the light source output after the correction is at least a minimum rated output at a position at which the output after the correction is lower than the minimum rated output, in the relation between a position on the surface of the photosensitive element in the main-scanning direction and the output after the correction, and modifies the correction data such that the light source output after the correction is at most a maximum rated output at a position at which the output after the correction is higher than the maximum rated output.

Abstract: An image forming apparatus that forms an image includes: a photosensitive element; an optical scanning device that includes a light source, and scans a surface of the photosensitive element in a main scanning direction with light emitted from the light source to form a latent image; a developing unit that develops the latent image; a photosensitive element period detecting sensor that detects a rotation period of the photosensitive element; a density sensor that detects a density variation of an image developed by the developing unit, in a sub scanning direction; and a processing device that corrects a driving signal of the light source according to the image information, based on an output signal of the density sensor and an output signal of the photosensitive element period detecting sensor.

Abstract: An image forming apparatus includes: a density detection unit that detects densities of an image developed by a developing unit at a plurality of positions in a main-scanning direction; a processing unit that obtains at least one of an amplitude and a phase of a first periodical density change of the image, of which cycle is a rotation cycle of a photosensitive drum, at the plurality of positions in the main-scanning direction on the basis of an output signal of the density detection unit, and corrects a drive signal for the light source so as to suppress the first periodical density change of the image at each position in the main-scanning direction on the basis of the rotation cycle of the photosensitive drum and at least one of the amplitude and the phase.

Abstract: An image forming apparatus is disclosed, including a light source; a drum; an optical scanning apparatus; and an endless belt. The image forming apparatus further includes a pattern forming unit which forms, on the endless belt along a conveying direction of the endless belt, a density fluctuation detecting pattern having a period; a density sensor which detects the density fluctuating detecting pattern and outputs a density signal including information on density fluctuations in the conveying direction of the endless belt; and a period detecting sensor which detects the period included in the density fluctuations.

Abstract: A deflector deflects a light beam emitted from a light source including a plurality of light-emitting units. A scanning optical system focuses the light beam deflected by the deflector on a scanning target surface. A monitoring photoreceiver receives a part of a light beam deflected by the deflector and directed toward an area within a scanning area outside an image area. A detecting unit individually detects emission powers of at least two light-emitting units based on an output signal of the monitoring photoreceiver in a single sweep of scanning.

Abstract: A light source drive device includes a first current source which provides a predetermined current to a light source corresponding to a predetermined light output, and a second current source which provides an overshoot current to the light source synchronized with the predetermined current. A processor is configured to set an overshoot time during which the overshoot current is provided to the light source. Further, an overshoot current is set which is applied to the light source. The overshoot time is set so that the overshoot time based on the rising of the predetermined current to when a light emission of the light source is detected.

Abstract: A light scanning apparatus having plural light sources includes a light source control unit configured to control the light sources to form L (L?2) light beam arrays aligned in a sub scanning direction each of which L light beam arrays are formed by causing M ((N?1)?M?1) light sources out of N (N?2) light sources assigned to each of the L light beam arrays to emit light as M light emitting sources, wherein each of the L light beam arrays forms a pixel and a total of L pixels aligned in the sub scanning direction are formed.