Digital workflow from the JDF specification

The Job Definition Format (JDF) introduced by the CIP4 organization was developed based on the Print Productiom Format (PPF) of the CIP3 and the Portable Job Ticket Format (PJTF) of the Adobe Corporation. , is the key technology to achieve digital printing workflow. Recently, the author reviewed the technical specifications of the JDF 1.3 version newly published by the CIP4 organization, and initially studied the JDF's operating structure, the components of the JDF workflow, and the JDF workflow, which gave a preliminary understanding and deepened the The understanding of digital workflow is written here for reference. Maybe my understanding is more one-sided, but I would like to initiate it for further discussion.

First, the structure of JDF

A job is a complete JDF project. Each job is organized in a tree structure and contains all the information needed to complete the intended project. Information is collected to nodes, each representing an intended job that is performed. Therefore, a JDF job consists of a set of nodes that describe the steps required to produce the final product. These nodes, in addition to being connected to inputs and outputs, are organized into hierarchical tree structures (as shown in Figure 1).

In order to better understand the workflow of JDF, the entire book is taken as an example to illustrate the meaning of each digital node in the JDF structure diagram (as shown in Table 1).

In the JDF structure, the uppermost nodes (eg, 1, 2 and 3) represent the product intent to be produced, ie, the desired final product and the composition of the product. In this example of making a book, the job has two sub-elements: the cover and the content. Each node must have clear and clear requirements. Therefore, nodes 2 and 3 must be further described. The content page includes color pages and black-and-white pages. Since different pages need to be processed differently, it requires a further branch of the tree structure. As a tree branch, each child node defines one element of a product. It has a unique set of characteristics, so the information contained within the node needs to be further described. For example, different media, different sizes or different color requirements, etc.

The nodes of the middle part of the tree structure (eg, 4, 5, and 6) represent the process groups needed to make each part of the product. In this example, the process group is shown in Table 2.

The nodes at the bottom of the tree structure (eg, 7-17) represent each individual process. Each node describes a single, simple process.

It can be seen that the workflow of JDF is determined by the structure of JDF. The more complex the structure, the stronger the functions of its workflow.

Second, the composition of the JDF workflow

The main components of the JDF workflow are composed of four parts, commonly known as Agents, Controllers, Devices, and Machines. These four main parts are used to generate, modify, determine routes, interpret and perform JDF tasks. At the same time, the workflow generated by these components is managed by a MIS (Management Information System).

(1) Machine Machine refers to the portion of a workflow system that is designed to perform a process, commonly referred to as a physical device. Like a printer or a binder, it also includes the software part for running a specific machine. Computer-based workstations, whether handled by automated processes or manually, are still considered machines if they are not connected to a JDF interface.

(2) Equipment The equipment must be a machine that can execute JDF nodes, start up, and actually run. The device must support JMF (Job Managing Format) information in order to interact dynamically with the controller. In the workflow system, the most basic function of the device is to execute the information specified by the media and the route specified by the controller.

(3) Anything used by the media to construct a JDF can be considered as a medium. The media is responsible for describing the JDF in the JDF workflow. It can generate a JDF job, add nodes and modify nodes in the existing job. The medium can be a software program, an automation tool, or a text editor.

(4) The controller media is used to generate and modify JDF information, and the controller is used to determine the route of the related device. The minimum requirement of the controller is to control at least one device to operate, or at least to control the sub-controller that makes one device up and running. In some cases, a controller such as a pyramid hierarchy can be built to control a series of low-level controllers by means of a controller at the top of the pyramid. However, the bottom-level controller of the pyramid must have the capabilities of the equipment. Therefore, the controller must be able to work together with other controllers.

In order for the controllers to communicate with each other and with the devices, the controller must support the exchange protocol of the JDF file and support JMF. The controller can also determine the process planning and scheduling data, such as process time and planned production volume.

In addition, the system that monitors the relationship between parts in a workflow is called a MIS management information system. MIS is a macro controller that directs and monitors the execution of all aspects of the workflow. Therefore, it must maintain contact with the actual production equipment, either by using the JMF information in real time or using the inspection records in the JDF.

To enable MIS to effectively communicate with components of other workflows, JDF provides important information services in the form of JMF, which can use a variety of information types, ranging from simple one-way communication to interrogation, and even commands. System designers have great flexibility in how they choose to use information structures.

Third, the JDF workflow

In the digital workflow system, the entire print job in the prepress, printing, postpress and other important links, with the help of JDF, from job submission to RIP, film output, plate making, inking, cutting, binding, and then sending The link becomes an interconnected workflow. This is determined by the structure of the JDF. JDF uses a structure to define the processes needed to produce each of the expected results and identify the elements needed to complete the processes. All processes are broken down into many nodes, and the entire job is represented by a tree structure with these nodes. All nodes together represent the required print.

Each of the JDF's 沽13. Apologetics 菔淙牒 菔淙牒 菔淙牒 菔淙牒 问 问 问 问 问 问 问 问 问 褂 褂 褂 褂 褂 褂 褂 褂 褂 褂 褂 褂 槌 槌 槌The output of the node should be the post-RIP image, but the output of the node should be the IP address and the layout of the image. The RIP image will become the input resource for describing the next node.

If the node does not represent the final product, the resources generated by one node may be modified or consumed by later nodes (such as supplies of ink, paper, etc.). In the printing process, the output product generated after a certain process is completed will become the input product of the next printing process, and so on, until all the processes are completed.

It is particularly emphasized that JDF operations, like any printing job, are defined according to the original intention of the final product. However, JDF operations are different from ordinary print jobs. The difference is that JDF allows the entire job to be pre-defined from pre-press to post-press. All the resources and processes needed in the entire print production can be identified and Arrange to the node. Therefore, a complete print job is completed in the JDF workflow by executing a series of nodes of the entire job, thus achieving the digital workflow of prepress, printing, postpress, and sending.

Fourth , understanding of the digital workflow

Through the preliminary analysis of the JDF specification, the author has a certain understanding of the digital workflow.

1. The digital workflow is a powerful system project. For digital workflows, due to its relatively late appearance and use, the knowledge of manufacturers and users is not the same. Often manufacturers emphasize the importance of digital workflows, and users consider it optional. From the perspective of JDF, the digital workflow itself is not a commodity, not a single product. Therefore, it is impossible for any manufacturer to create a set of workflow products that can be sold.

JDF in the digital workflow, regardless of the number of related departments in the entire job, what kind of process steps and equipment are used in the form of "node" to define. By implementing a series of printing processes represented by "nodes", not only can production management and management information systems be organically linked, but also all links in prepress, printing, postpress, postal, etc. printing can be integrated, and all Information, such as production schedules, job schedules, real-time tracking of jobs and equipment, is shared by the entire system. Therefore, the all-digital workflow connected through the JDF "nodes" is a powerful system engineering (as shown in Figure 2). It controls the entire printing process with high degree of integration and automation, and improves printing quality and production efficiency. All play an important role.

2. The conditions that must be met to achieve a digital workflow

Workflow is an information technology that uses electronic systems to manage and monitor the production process. In the printing industry, digital workflows are based on digital production control information to automate and highly integrated the production of printed products. To achieve a fully digital workflow, two conditions must be met.

(1) Increasing digitization

Digital workflows have been developed on the basis of digital information. Therefore, the digitalization of print production processes is increasing. Digital data files, digital proofing, digital printing equipment, and computer-managed production and office system data flow are used to enable the entire process flow to be digitized, standardized, standardized, networked, and adopt new technologies such as ICC color management. This condition is a prerequisite for printing companies to implement digital processes.

(2) Has a compatible and powerful set of industry standards

In this regard, the CIP4 organization has established relevant standards for the printing industry, such as PDF, JDF and so on. The key is how to use these industrial standards to develop a workflow that meets the printing company's requirements. At present, many manufacturers have developed new products, such as Agfa's: Apogee X, Heidelberg's Meta Dimension, Kodak's Prinergy, Screen's Trueflow 3, and Beijing University Founder's Changliu, which all provide digital printing workflows. Very good solution.

In foreign countries, the application of the all-digital workflow system based on the JDF specification has begun to gain popularity. In China, there are great differences in the degree of knowledge and application of digital workflows among different printing companies. Overall, it is still at the initial stage. Although the mechanization, automation, and digitization of our country's printing production process have been greatly improved, prepress, printing, and postpress processing often lack organic links, and the application conditions for implementing a fully digital workflow are still not mature.

Some printing companies in China have initially formed a digital workflow based on DTP and a digital workflow based on CTP, which has laid a solid foundation for the realization of a fully digital workflow.
The application of digital workflow is an inevitable trend in the development of the printing industry. Both large and small enterprises should work hard in this direction. At present, based on the specific situation of the company, based on reality, focus on the future, step by step, to create conditions for the application of digital workflow.