Color tone control method for printing press

• US 20030136287A1
• Filed: 12/27/2002
• Published: 07/24/2003
• Est. Priority Date: 12/27/2001
• Status: Active Grant

• Current Assignee: Mitsubishi Heavy Industries Printing & Packaging Machinery Company Limited (Mitsubishi Heavy Industries, Ltd.)
• Original Assignee: Mitsubishi Heavy Industries, Ltd.
• Inventors: Yamamoto, Shouji
• Granted Patent: US 6,722,281 B2
• Time in Patent Office: Days
• US Class Current: 101/484
• CPC Class Codes: B41F 33/0036 Devices for scanning or checking the printed matter for quality control
• CPC Class Codes: B41F 33/0045 for automatically regulating the ink supply

Abstract

The object of this invention is to provide a method for providing direct control of the ink supply for printing presses based on an output of the multispectral measurement means.

This method comprises the steps of obtaining an output of said multispectral measurement means from a plurality of said printed item which are printed while varying the amount of ink dispensed, by utilizing percentage dot area information in print editing from a printing plate for said printed item; determining a transfer function to calculate the amount of ink dispensed corresponding to the amount of change in the multispectral output by said output; and computing the amount of ink dispensed to be changed, by using the output deviation in said multispectral measurement means'"'"' output from the target colors for a commercially printed item, and said percentage dot area information related to the target colors of the commercially printed item to control the amount of ink dispensed by the foregoing ink dispensing apparatus.

Claims

1. A Color tone control method for a printing press which incorporates an ink dispensing apparatus that can either electronically or mechanically vary the amount of ink dispensed, and which controls the color tone based on a printed item measured by a multispectral measurement means to control said ink dispensing apparatus said method comprising steps of:

obtaining an output of said multispectral measurement means from a plurality of said printed item which are printed while varying the amount of ink dispensed, by utilizing percentage dot area information in print editing or utilizing percentage dot area information measured from a printing plate for said printed item;

determining a transfer function to calculate the amount of ink dispensed corresponding to the amount of change in the multispectral output by said output; and

computing the amount of ink dispensed to be changed, based on the output deviation in said multispectral measurement means'"'"' output from the target colors of a commercially printed item, and said percentage dot area information related to the target colors of the commercially printed item by using said transfer function in order to control the amount of ink dispensed by the foregoing ink dispensing apparatus.

2. A Color tone control method according to claim 1, wherein said transfer function is determined for the information of each set of printing materials.

3. A Color tone control method according to claim 1, wherein the contribution rate is added to determine said transfer function, and said contribution rate includes the amount of the surrounding effects caused by the swing roller movement and amount of ink transfer by using the percentage dot area information in the surrounding area.

4. A Color tone control method according to claim 1, wherein the number of channels for said multichannel measurement means is determined according to the number of colors to be used by the printing press, and the number of two-color chromatic color combinations.

5. A Color tone control method according to claim 1, wherein said transfer function to calculate the spectral reflectance or color coordinates is determined by said multispectral measurement means.