摘要:
A light scanning unit, a method of detecting a failure of a synchronization signal, and an electrophotographic image forming apparatus using the light scanning unit are provided. The light scanning unit includes a synchronization sensor which receives a portion of a light beam that is emitted from a light source and then deflected and scanned from a light deflector, to detect a horizontal synchronization signal. A width of a light-receiving surface of the synchronization sensor in a main scanning direction varies along a sub scanning direction. The light scanning unit having the above-described structure determines a high quality or a failure of a synchronization signal by using a width of a horizontal synchronization signal detected in a test operation.
摘要:
A pixel clock generator includes a frequency divider 4 that generates a pixel clock PCLK based on a high frequency clock VCLK, a comparator 5 that calculates an error Lerr in the time obtained by integrating a cycle of the pixel clock PCLK for a target number RefN from a time when synchronization signals SPSYNC and EPSYNC are detected, a filter 6, and a frequency calculating unit 7 that sets a frequency dividing value M of the frequency divider 4. The filter 6 and the frequency calculating unit 7 calculate an average of a frequency of the pixel clock PCLK based on the error Lerr, determine a reference error value from the error Lerr in N-cycles, calculate offset values of the frequencies of N pieces of pixel clocks PCLK based on a difference between the reference error value and the error Lerr, and calculate the frequency dividing value M based on a result obtained by adding the circularly selected offset values and the average of the frequency of the pixel clock PCLK.
摘要:
In a control apparatus, first type binary image data representing density of pixels arranged along a first image direction at a first resolution is acquired, and a first determining process is executed to determine an exposure pattern used to execute exposures of exposure lines at a second resolution lower than the first resolution along a first exposure direction. In the first determining process, a partial exposure pattern for exposing an output partial area that is correlated with a binary partial area and that overlaps N successive exposure lines is determined such that distribution of exposure amounts in the output partial area along the first exposure direction differs according to layout of second-value pixels in the binary partial area at least in the first image direction, thereby enabling an image of color material to be formed through development at a resolution higher than the second resolution in the first exposure direction.