Image forming device
First Claim
1. An image forming device comprising a plurality of image optical scanning recording sections, each image optical scanning recording section starting image recording by line scanning in accordance with an image signal when the number of clocks of a reference clock signal counted in synchronization with a line scanning synchronizing signal reaches a predetermined number, wherein:
- at least one of said image optical scanning recording sections has frequency varying means for varying a frequency of the reference clock signal thereof,said image forming device further comprising;
control means for controlling said frequency varying means so as to adjust the frequency of the reference clock signal based on an offset of an image recording start position of said image optical scanning recording section in a main scanning direction crossing a proceeding direction of a transfer material so that the image recording start position coincides with an image recording start position of the other image optical scanning recording section; and
wherein;
the image signal is composed of color image signals resulting on color decomposition;
the plurality of said image optical scanning recording sections correspond to the color image signals, respectively, andpairs of said image optical scanning recording sections are formed, and said control means controls the reference clock signals so that in each pair, a reference clock signal of one image optical scanning recording section is adjusted by referring to a reference clock signal of the other image scanning recording section.
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Accused Products
Abstract
A conventional image forming device having a plurality of image optical scanning recording sections has had a drawback of being incapable of correcting printing positions of the image optical scanning recording sections with high precision by using a small-scale circuit. In the case of an image forming device of the present invention, a variable clock generator 114 having a voltage control oscillator (VCO) 114a is provided therein as reference clock signal generating means of laser control system of each of image optical scanning recording sections (LSU) for cyan, yellow, and magenta. By so doing, during an invalid printing period prior to a valid printing period, frequencies of the reference clock signals of the LSUs for cyan, yellow, and magenta are adjusted in accordance with offsets of printing start positions of these LSUs with respect to that of the LSU for black, so that printing offsets are eliminated. As a result, the printing start positions are made to coincide with each other with high precision even with a small-scale circuit.
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Citations
24 Claims
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1. An image forming device comprising a plurality of image optical scanning recording sections, each image optical scanning recording section starting image recording by line scanning in accordance with an image signal when the number of clocks of a reference clock signal counted in synchronization with a line scanning synchronizing signal reaches a predetermined number, wherein:
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at least one of said image optical scanning recording sections has frequency varying means for varying a frequency of the reference clock signal thereof, said image forming device further comprising; control means for controlling said frequency varying means so as to adjust the frequency of the reference clock signal based on an offset of an image recording start position of said image optical scanning recording section in a main scanning direction crossing a proceeding direction of a transfer material so that the image recording start position coincides with an image recording start position of the other image optical scanning recording section; and wherein; the image signal is composed of color image signals resulting on color decomposition; the plurality of said image optical scanning recording sections correspond to the color image signals, respectively, and pairs of said image optical scanning recording sections are formed, and said control means controls the reference clock signals so that in each pair, a reference clock signal of one image optical scanning recording section is adjusted by referring to a reference clock signal of the other image scanning recording section. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. An image forming device comprising:
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a plurality of image optical scanning recording sections, each image optical scanning recording section including; reference clock signal generating means for generating a reference clock signal; image signal generating means for generating an image signal in accordance with the reference clock signal; and synchronizing signal generating means for generating a line scanning synchronizing signal for synchronization of line scanning with respect to each line, so that each image optical scanning recording section starts image recording by line scanning in accordance with the image signal when the number of clocks of the reference clock signal counted since generation of the line scanning synchronizing signal reaches a predetermined value, wherein; reference clock signal generating means of at least one among said image optical scanning recording sections has frequency varying means for freely adjusting the frequency of the reference clock signal, said image forming device further comprising; control means for, by using said frequency varying means, adjusting the frequency of the reference clock signal so that an offset of an image recording start position of said image optical scanning recording section having said frequency varying means with respect to an image recording start position of the other image optical scanning recording section is eliminated; and wherein; the image signal is composed of color image signals resulting on color decomposition; the plurality of said image optical scanning recording sections correspond to the color image signals, respectively, and pairs of said image optical scanning recording sections are formed, and said control means controls the reference clock signals so that in each pair, a reference clock signal of one image optical scanning recording section is adjusted by referring to a reference clock signal of the other image scanning recording section.
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Specification