Three ways to teach you how to do online quality inspection

We are a big printing company in Shenzhen China . We offer all book publications, hardcover book printing, papercover book printing, hardcover notebook, sprial book printing, saddle stiching book printing, booklet printing,packaging box, calendars, all kinds of PVC, product brochures, notes, Children's book, stickers, all kinds of special paper color printing products, game cardand so on.

For more information please visit

http://www.joyful-printing.com. ENG only

http://www.joyful-printing.net

http://www.joyful-printing.org

email: info@joyful-printing.net

Print quality online detection and control generally includes three types of registration detection and control, color detection and control, printed graphic detection and control.

Whether it's a sheetfed offset press or a web offset press, the following three registration detection and control systems are available.

1 offline register detection and open loop control system

The operator can hold the registration mark reader to measure the position of the vertical and horizontal registration marks of the printed sheet, and adjust the relevant parts of the plate cylinder by calculating the difference between the actual measurement data and the standard sample registration data.

2 Online registration detection and open loop control system

During the printing process, the online registration detection and open-loop control system on the printing machine can automatically detect the position of the longitudinal and horizontal registration marks of the sample. When the difference between the detection data and the standard sample registration data exceeds the specified registration tolerance range The operator can make appropriate adjustments according to the actual situation.

3 online registration detection and closed-loop control system

During the printing process, the online registration detection and closed-loop control system installed on the printing machine can automatically detect the position of the longitudinal and horizontal registration marks of the sample. The registration control system compares the actual detection data with the original set registration data. The relevant parts such as the plate cylinder are adjusted according to the size of the tolerance range.

Color detection and control

Currently, color detection is divided into two methods: density measurement and color measurement.

1 density measurement

Density measurement refers to measuring the density of the ink film using a densitometer. There is a corresponding relationship between the thickness and density of different ink ink films, and the printing operator can directly calculate the ink supply adjustment amount of each ink key by using the difference between the printed matter density measurement value and the standard sample density value, and the corresponding printing unit The inking system is adjusted.

2 chromaticity measurement

Chroma measurements can be divided into two types: colorimeter measurement and spectrophotometer measurement.

The colorimeter measurement is based on colorimetry and uses the measured tristimulus values to precisely control the printing process to ensure that the color of the print is consistent with the color of the standard proof.

The spectrophotometer measures the reflectivity of light at various wavelengths in the visible spectrum of the surface of the printed sheet. The tristimulus value or density value of the color is calculated by software based on the measured reflectance of the surface color of the sheet color.

Generally, the adjustment amount of the relevant ink key is calculated according to the measurement data, thereby adjusting the ink supply amount of each relevant ink key to ensure the consistency of the color of the printed product and the color of the standard proof.

Printed graphic detection and control

The detection of printed graphics mainly includes: layout detection, handwriting detection, missing printing, dirty spots, white spot detection and printing paper defect detection.

Printed graphic inspection and control systems can be designed as specialized inspection and control systems, or combined with registration, color detection and control systems to form a comprehensive inspection and control system. The color difference and various defects between the printed product and the standard proof are detected by scanning the printed product, and processed by the console related detection and control system.

The use of printed quality inspection and control system can not only ensure the stable output of high-quality printed products, reduce the scrap rate and related losses, but also shorten the adjustment time, improve the effective utilization of the machine, reduce the number of over-printed paper, and thus reduce the cost. effect.