| 摘要 |
A printing press may be provided with a first rotatable printing roller that prints ink of a first color on a web of material and causes a first pair of registration marks to be periodically printed in the first color on the web, a second rotatable printing roller that prints ink of a second color on the web of material and causes a second pair of registration marks to be periodically printed in the second color on the web , a third rotatable printing roller that prints ink of a third color on the web of material and causes a third pair of registration marks to be periodically printed in the third color on the web, an imaging device positioned to detect the registration marks print ed on the web that generates image data representing the registration marks, and a controller operatively coupled to the printing rollers and the imaging device. The controller may include a processor and a memory, and the controller may be programmed to identify the pairs of registration marks based on the image data and based on registration mark reference data for at least three registration mark pairs defined by a registration mark relationship table.
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