Quality Control Devices

P274-291Insert 7-8

Pro.Dr.Cao Congjun

Xi’an university of Technology

测控条的测控原理

测控条 (Quality control strip/target)：由网点、实地、线条等测标组成的用于判断和控制拷贝、晒版、打样和印刷时信息转移状况的软片条。

1. 网点面积的扩大与网点边缘长度总和成正比。线数高时，总边长大，网点扩大值越大。用于检测网点扩大值。e.g. Brunner 50%粗网和 50%细网 / GATF字码信号条

2. 用几何图形位置相等、阴与阳相反等原理控制网点大小和形状。

3. 边缘增大条件下，角度处比弧度出变化更敏感。e.g. GATF星标、放射楔形线

e.g. Brunner阴阳十字线和阴阳网点

4. 利用 50%面积的等宽折线控制不同方位的变化。e.g. Brunner 50%细网段的折线

5. 用等宽线的同心圆控制任意方位的变形。e.g. GATF星标、放射楔形线

GATF-the Graphic Arts Technical Foundation

The GATF T-Mark consists of a configuration of thin, accurately ruled lines that are used to identify image centers, folds, trims, and bleeds during printing production (figure 12.16).

The GATF Star Target is a small, circular pattern of solid and clear pie-shaped wedges (figure 12.17).

When printed on a press sheet,the Star Target gives the press operator a quick and effective measure of ink spread,slur,and doubling (figure 12.18).

Ink spread: Spreading in all directions of the edges of ink dots and lines on the press sheet beyond their corresponding areas on the plate.

Doubling:Printing of a double image, which consists of a full solid and a weak second image slightly out of register with the full solid.

Slur:Smearing 拖尾 of the trailing edges of dots,resulting in ink film tapering 逐渐减少 into the white areas.

Dot Gain

The GATF Quality Control Strip The GATF Quality Control (QC) Strip is a

patterned devices that helps the press operator control print quality throughout the press run.

OK sheet

The GATF Dot Gain Scale and Slur Gauge

The GATF Dot Gain Scale is designed to give numerical values to any dot sharpening or dot gain,The scale is made up of ten 200-line screen tint steps which are graduated in density. These steps form numbers from 0 to 9 on a uniform background of 65-line tint density.

Testform测试版 A test form is a comprehensive diagnostic and

measurement tool designed to help the printer achieve higher quality color printing with less waste and reduced make-ready time.

GATF test forms contain a variety of quality control targets in addition to color reproduction targets. The quality control targets can be divided into three categories according to their use: diagnostic targets, process control targets, and standardization targets. Although some quality control targets can be used for more than one purpose, the functions remain distinct.

• Diagnostic Targets are used to troubleshoot printing systems

Ladder Bars Star Targets • Process Control Targets are used to monitor the printin

g system Color Control Bar Tone Scales Vignettes[vinjet] 小插图 Color Reproduction Guides • Standardization Targets are used to measure the attrib

utes of the printing system Gray Balance Chart Ink Coverage Chart

Print test form

Print test form

Gray balance Target

Color Bar & Solid Strip

Ink Trapping Target

Register Target

Homework

P292 Review questions 6,14.