Digital Workflow and Quality Control in Direct Platemaking System

The maturity of computer-to-plate technology and the large number of applications in plate printing have changed the traditional production work, making the digital workflow a bright spot in platemaking and printing. This article describes the way in which Xi'an Co., Ltd.'s map printing company uses the Heidelberg CTP technology to achieve digital workflows, improvements to traditional production work, and quality control in digital workflows.

Computer-to-plate (CTP), digital proofing, and digital printing have been accepted and widely used by printing companies around the world. Advanced digital workflows have brought about changes in prepress production workflows. Printing products efficiently, quickly, and with high quality reflects the advantages of the digital workflow. At the same time, it is also the common goal pursued by customers and printing companies. The digital workflow is the most critical means and effective way of quality control. Produced under the control of digital workflow, the superior performance of CTP technology will be applied and reflected in high-quality printing products.

1. Digital workflow improves desktop publishing production

Using the CTP system, image data processing, text typesetting, layout processing, and plate output are all performed under the control of the digital workflow. The work management processes of the color management system, the print simulation management system, the plate output management system, and the computer software are realized. Seamless connection, quality control in the production process can be based on. Because the manual proofing and photometric output in traditional production work is no longer needed, the impact of man-made and environmental factors in the production process is reduced, the production work is simplified, the flow of quality control is realized, and the product quality and production efficiency are improved.

2. Digital workflow computer hardware and software system structure

The system construction of the digital workflow of Xi'an Coal Airline Map Printing and Printing Company is divided into hardware and software. Hardware includes PC and Mac personal graphics workstations, imposition workstations, raster processor workstations, digital proofer, spectrodensitometer, plate density meter, CIP3 output interface, Heidelberg Dingsheng 102 direct platemaking machine. The software component consists of Heidelberger's ViewOpen, PrintOpen, Delta RIP, NewColor software, Barco's Packedge, FastLane, SecuSeal, ArtiosCAD, Mapedge, QuickStep software, and Adobe's graphics and image processing software. Digital production workflow quality control is shown in the right figure.

The digitized workflow implements a tower logic structure that combines computer software and hardware with a digital management workflow. Prepress work is easy to control, simple and efficient, and it realizes digital and process control as a whole, which changes traditional quality control methods and avoids the loss of quality control caused by human factors, environmental changes, and machine factors in the traditional workflow. The high accuracy of image color restoration, quality control for printing machine features, text, layout, and pre-press computer simulation error correction control ensure high-quality production of CTP systems under digital workflow control.

3. Digital Workflow Quality Control Software Process

In the digitized workflow of Xi'an Coal Airline Map Printing and Printing Company, quality control by computer software is the most important and the key to digital workflow.

To output high-quality printing plates and print high-quality products, digital quality control is required during image scanning input. During image scanning, Heidelberg's ViewOpen and NewColor software quality control is implemented to realize digital monitoring and conversion of LCH, RGB, and CMYK color spaces, ensuring that the printed manuscript, reflected manuscript, and transmitted manuscript are subjected to image color quality control according to printing requirements. Achieve faithful reproduction of original colors and ensure that computer screens in the RGB color space display color by printing effect.

Barco's FastLane and Packedge imposition software can rasterize PS files and re-edit before digital proofing; correct errors in folding, layout, and text found during computer screen corrections; check printing color space Legitimacy; color checking on the computer screen; automatic trapping in the layout file; previewing the color separation effect of the layout file and performing soft proofing on the screen. Barco's ColorTone software can simulate printing characteristics, achieve soft proofing of images on a computer screen in the CMYK print color space, and control image color quality.

The large version of the file processed under effective digital control is processed by Delta RIP software for layout proofing and digital proofing. The excellent performance of Delta RIP software enables it to simulate printer characteristics and paper properties under the control of PrintOpen software from Heidelberg, perform digital proofing, correct errors and generate digital profiles for color management. After the color management is completed, the Delta RIP software realizes the quality control of the output plate of the Dingsheng 102 plate-making machine. Delta RIP software has built-in linear and dot-net control management modules for printing plates and printing presses. Based on the printing presses of different printing companies, it has developed printing dot enlargement and reduction standards and used characteristic curves to adjust the printing presses to ensure that the printing press meets quality control standards. Combining CIP3 data, the printing press prints high-quality advertising products, periodical album products, and atlas products, and realizes digital control and process software control of computer direct plate making.

4. Hardware flow of digital workflow quality control

A complete CTP production line not only needs a complete software control process, but also has a powerful hardware system that is compatible with it. The CTP production line of Xi'an Coal Airline Map Printing and Printing Company has Barco's true color graphics workstation display, which ensures the correct color temperature and hue stability under normal working environment, and realizes the correct analog display of printed colors and the color before printing digital proofing. control.

Heidelberg's NexScan and PrimeScan high-end scanners meet the requirements of high-quality image scanning, and can acquire scanned images with rich color hierarchies and high color saturation to meet high printing requirements, enabling original colors to be reproduced with high accuracy.

The HP DesignJet 5000 PS3 Digital Proofer ensures color printing that is larger than the print color gamut, enabling digital proofing to be matched with printing, plus a color management system from Shanghai Fort Worth to achieve quality control of digital proofer simulation press features.

Heidelberg's Dingsheng 102 direct platemaking machine, which uses the thermal plate of Kodak PolyLight, and the digital stenciling machine of Denmark's Gu Longyan, which has good exposure and imaging conditions, digitalized monitoring and automatic adjustment of developing conditions, and stable plate output quality. . The printing plate has a high accuracy of the printing press, high printing resistance, high printing stability, and strict quality control. On this basis, the product is measured and controlled by a spectrodensitometer and a plate densitometer, in order to cooperate with the software process to realize digital monitoring in the digital workflow, and to ensure strict quality control from beginning to end in printing production.

The promotion and application of CTP technology will certainly replace the traditional printing workflow. Changes in the workflow have brought about changes in the printing work. Printing companies and customers are skeptical of the prepress work in the new workflow, and are worried about the quality control of printed products. Practice and application prove that the digitized work flow realizes digital work control and print quality control and is an effective way and means for CTP system production and quality management.


Source: Digital Printing Su Chunrang