US 2001/0012042 A1 · Image recording apparatus and method of generating pixel clock

Abstract

An image is accurately recorded by a light beam on a PS plate wound on a drum which is rotating at a constant speed. A rotary encoder detects information of a recording position in a main scanning direction by the light beam that is emitted from an optical unit to the PS plate. Based on the detected information, a PLL circuit of a recording synchronizing signal generating unit generates an original clock. Pulses of the original clock are counted by a decimating counter, which outputs a decimating instruction to decimate a pulse from the original clock each time the count reaches a preset count. Based on the decimating instruction, a pulse is decimated from the original clock, and a decimated clock is frequency-divided at a fixed frequency-dividing ratio by a frequency divider, which outputs a pixel clock for recording the image. Since the frequency of the pixel clock is varied by decimating the original clock based on the preset count, the image can accurately be recorded on the PS plate by determining in advance the preset count depending on the positional relationship between the PS plate and the optical unit.

Claims20

Dependent claims

An image recording apparatus comprising:

image recording means for scanning a recording sheet in a main scanning direction to record an image on the recording sheet, said image recording means being movable in an auxiliary scanning direction substantially perpendicular to the main scanning direction to record a two-dimensional image on the recording sheet;
means for detecting recording position information in said main scanning direction;
original clock generating means for generating an original clock based on said recording position information in said main scanning direction;
decimation counting means for counting pulses of said original clock and outputting a decimating instruction to decimate a pulse from said original clock each time a preset count is reached;
decimating means for decimating a pulse from said original clock based on said decimating instruction;
and
frequency-dividing means for frequency-dividing a decimated clock at a fixed frequency-dividing ratio and outputting the frequency-divided clock as a pixel clock for recording the image.

4 more elements

A method of generating a pixel clock to correct a graphical accuracy distortion of an image recorded on a recording sheet in an image recording apparatus which has image recording means for scanning a recording sheet mounted on a mechanical component in a main scanning direction to record an image on the recording sheet per pulse of the pixel clock, said image recording means being movable in an auxiliary scanning direction substantially perpendicular to the main scanning direction to record a two-dimensional image on the recording sheet, said method comprising the steps of:

generating (S1-S4) mechanical component correcting data based on a relative positional relationship between said mechanical component and said image recording means;
and
controlling a time to generate the pixel clock to energize said image recording means based on said mechanical component correcting data and proportional component correcting data corresponding to recording conditions for said image recording means to record the image on said recording sheet, when the image is recorded on said recording sheet by said image recording means.

An image recording apparatus comprising:

image recording means for scanning a recording sheet mounted on a mechanical component in a main scanning direction to record an image on the recording sheet per pulse of a pixel clock, said image recording means being movable in an auxiliary scanning direction substantially perpendicular to the main scanning direction to record a two-dimensional image on the recording sheet;
means for detecting recording position information in said main scanning direction;
original clock generating means for generating an original clock based on said recording position information in said main scanning direction;
decimation counting means for counting pulses of said original clock and outputting a decimating instruction to decimate a pulse from said original clock each time a preset count is reached;
decimating means for decimating a pulse from said original clock based on said decimating instruction;
frequency-dividing means for frequency-dividing a decimated clock at a fixed frequency-dividing ratio and outputting the frequency-divided clock as a pixel clock for recording the image;
storage means for storing mechanical component correcting data based on a relative positional relationship between said mechanical component and said image recording means;
and
decimating value calculating means for calculating said preset count from said mechanical component correcting data stored in said storage means and proportional component correcting data corresponding to recording conditions for said image recording means to record the image on said recording sheet, and setting the calculated preset count in said decimation counting means.

6 more elements

Dependencies are inferred from the claim text.

Image recording apparatus and method of generating pixel clock

Life of this patent

Image recording apparatus and method of generating pixel clock

Life of this patent

Abstract

Claims20