Abstract:
An image forming apparatus includes an intermediate transfer body; a generating unit generating test pattern data; a storage unit storing a color displacement amount; a correcting unit correcting the test pattern data and image data based on the color displacement amount currently stored in the storage unit; a forming unit forming a test pattern based on the test pattern data corrected by the correcting unit on the intermediate transfer body at predetermined intervals, and forming an image based on the image data corrected by the correcting unit on the intermediate transfer body; a detecting unit detecting the test pattern formed on the intermediate transfer body; an updating unit determining an amount of change of the color displacement amount from a result of detection by the detecting unit, and updating the color displacement amount stored in the storage unit by using the amount of change of the color displacement amount.
Abstract:
A pixel clock generating device includes a time interval detection unit detecting a time interval between a first signal and a second signal in each of cyclically repeating N (≧2) time periods; a comparing unit cyclically selecting a target value from N target values corresponding to the N time periods and outputting an error indicating a difference between the detected time interval and the selected target value for each of the N time periods; a frequency calculation unit correcting a frequency of the pixel clock signal based on the error and cyclically generating a frequency specification signal indicating the corrected frequency for each of the N time periods; a high-frequency clock generating unit generating a high-frequency clock signal; and a pixel clock generating unit generating a pixel clock signal based on the frequency specification signal and the high-frequency clock signal.
Abstract:
A first trial write process obtains an optimum recording power of a test pattern even with respect to data having different rules for the recording waveforms corresponding n type data length sets, and a second trial write process using this optimum recording power obtains optimum pulse width or optimum pulse edge position separately for each data length set. Based on the optimum recording power and optimum recording waveform obtained by these trial write processes, recording operation is performed so as to form all the data lengths with satisfactory accuracy, thereby making it possible to obtain a proper reproduced signal.
Abstract:
A comparator compares a time interval between a first synchronization signal and a second synchronization signal with a target value, and outputs an error therebetween. A frequency calculator calculates a set value of a pixel clock frequency based on the error output from the comparator, and outputs a frequency specification signal for specifying a pixel clock frequency according to the calculated set value. A frequency divider divides a high frequency clock generated by a high frequency clock generator by a frequency division ratio based on the frequency specification signal output from the frequency calculator, and generates the pixel clock.
Abstract:
A disclosed device for generating a pulse-width modulated signal according to image data and based on a pixel clock signal includes a pixel clock generating unit configured to generate the pixel clock signal and a modulated data generating unit configured to generate the pulse-width modulated signal. The pixel clock generating unit includes a multi-phase clock signal generating unit, a comparing unit, a frequency calculation unit, a counting unit, and a pixel clock signal output unit. The modulated data generating unit includes a data converting unit, an edge time calculation unit, and a pulse-width modulated signal output unit.
Abstract:
A light source drive which modulates a light source so as to cause the same to emit a light, includes: a superposition current generation part which generates a superposition current approximately corresponding to a charging/discharging current needed for a capacitance occurring in parallel to the light source for a predetermined time period near at least one of a rising-up part and a decaying-down part of a waveform of a drive current for the light source; and an addition/subtraction part which adds to or subtracts from the drive current the superposition current generated by the superposition current generation part.
Abstract:
In a method of transforming a recording power level into multi-levels by using an extra recording power level, the optimum value of each recording power level is obtained, thereby achieving recording with good accuracy. By including a first test writing step (S1–S3) of performing test writing of predetermined first test data while varying the recording power in stages, and calculating an optimum recording power from the reproduction signal, and a second test writing step (S4–S6) of setting the recording power to the calculated optimum recording power and performing test writing of predetermined second test data while varying in stages the extra recording power applied in a part of a time period in which the optimum recording power is applied, and calculating an optimum extra recording power from the reproduction signal, the recording power and the extra recording power are separately calculated by test writing, and with which information is recorded. Hence, it is possible to form the shape of a recording mark and the mark position with good accuracy. Thus, recording can be performed with good accuracy.
Abstract:
In an information recording method and apparatus, a sequence of sync frames indicative of data is recorded onto tracks of an optical recording medium. In the recording medium, prepits are formed on lands between the tracks at given intervals, and sync patterns, providing synchronization on a sync-frame basis, are inserted in the sync frames such that each sync pattern has a length in a track direction larger than a length of one of the prepits and a position of each sync pattern matches with a position of at least one of the prepits. Codes that represent sync patterns for the sync frames are selected such that each sync pattern is formed as a space on the recording medium. Modulation codes are generated based on the sync frames in which the selected codes are inserted, by modulating the sync frames containing the selected codes in accordance with a predetermined modulation scheme. A sequence of recording pulses is generated by converting the modulation codes through a predetermined conversion scheme. A prepit position signal is detected from one of the prepits for each of the sync frames during the writing of the recording pulses to the recording medium, so that a write position control is performed based the detected prepit position signal. Further disclosed in an optical recording medium which is appropriate for use with the information recording method and apparatus.