Impact of JDF on Postpress Equipment Development

The establishment of the JDF standard reflects the overall trend of digital prepress technology in-depth development of printing and post-press processing. The purpose is to achieve the integration of the three major processes of prepress, printing and post-press processing, as well as the integration of production activities and business management activities. It helps companies to organize production according to standardized procedures. However, it may not be the printing companies that bear the brunt of the influence of the JDF standard, but the companies or departments that are engaged in the research and development of equipment and systems.

introduction

In fact, post-press processing has no effect on print quality, but it affects print quality. The quality of printing depends on prepress and printing processes, equipment, materials, and technology. It is also related to operator and factory management. One of the goals of establishing a JDF standard and then developing a digital workflow system is to minimize human factors to the end result. The impact of the formation of a stable and continuous production process. The quality of printing is controlled by many factors and the relationship is quite complicated. Judging the print quality is not an easy thing because the print is first of all a visual product, subjective quality judgment is unavoidable. However, the subjective quality judgment also brings about the randomness or personality of the result. The judgment result varies from person to person.

Printed matter should be a complete industrial product. In addition to providing graphic content, it should also have the use of functions that meet the needs of consumers, and sometimes it is necessary to protect the printed content, and it may also serve as a beautification. The use of print functions or other additional attributes cannot be provided by prepress and printing processes, and it is mainly guaranteed by postpress processing.

Since the post-press processing technology is basically independent of the printing quality, the quality of the post-press processing inspection and evaluation method is also different from the inspection and judgment of the printing quality. It should have its own unique inspection method and evaluation standard. However, it must be pointed out that the establishment of the JDF standard did not solve the problem of quality inspection and evaluation of post-press processing because the JDF standard was neither a print quality nor a print quality standard. In fact, the JDF standard is used to guide system integration, digital workflow software development, and equipment production. It considers the standardization of production from the system perspective and strengthens the link between production resources and elements.

Post-printing JDF process

JDF regulates production behavior and guides equipment manufacturing and system software development by defining critical printing processes or processes. To sum up, there are 28 prepress processes defined by the JDF standard, in addition to the 10 general processes involving commercial activities and corporate management, such as layout control, color control, preflight inspection, ink zone generation, color separation, and imposition. Etc.; two printing processes, namely traditional printing and digital printing. The earlier version of integrated digital printing was cancelled due to the addition of a combination process node in the new version of the JDF standard. Although the number is small, the content of control is very large, and thus it is not simple. . Post-press processing faces a large number of production processes and equipment, so the JDF-defined post-press processing process is also the most, a total of more than 40 kinds.

In general, the post-press processing process is divided into two major types of books and packaging, but some processes apply to both, such as cutting, punching, tying, and carton packaging. In principle, each type of post-printing process corresponds to a device. A slightly more complex device may be decomposed into two processes. For example, a device that provides die-cutting and indentation functions at the same time can be decomposed into two types of post-printing processes: die cutting and indentation. However, the multifunctional features of post-press processing equipment are not as typical as those of digital printing machines. Currently, digital printing machines that face the commercial market are often integrated before printing (called digital front-end systems), printing, and post-press processing.

Post-press processing related to books and magazines includes book case preparation, book cover making, book cover insertion, soft cover application, creases, folding, collating, matching posts, inserts, spine preparation, gluing, and spine attachment. Binding, metal clip binding, plastic comb binding, spiral binding, ring binding, saddle stitching, lock stitch binding, plastic wire binding, wire comb binding, capping cloth, sealing and cutting . It can be seen that JDF has defined the postpress printing process quite well and may be related to the equipment manufacturing companies participating in the standard setting.

The post-press processing processes mainly used for packaging include number printing, laminating, indentation and die cutting. It can be seen that the definition of the packaging and post-printing process by JDF is not yet sufficient, and it may be that the new version of the JDF standard needs to be added.

There are many processes it is difficult to define whether it should belong to the book printing or packaging printing processing, such as cutting paper, labeling, punching, stacking paper, tightening and baling, carton packaging, bale wrapping, winding packaging and web cutting. Wait.

The main purpose of listing these processes is to introduce the overall concept of the JDF standard, to understand the relationship between the JDF standard and prepress, printing, and postpress processing, to specify which features can be implemented through the JDF standard, or to allow entry points to solve problems.

The main task of postpress processing equipment development

As long as equipment manufacturers want their own equipment to be compatible with JDF workflows and require integration into digital workflow systems, they must design and manufacture equipment in accordance with JDF standards. As with computer network interconnection, physical integration is always at the bottom, providing the foundation and guarantee for integration of process integration and management elements, and the interconnection of devices through related hardware. The existing equipment of a printing plant cannot be integrated into a digital workflow unconditionally. Newly-manufactured equipment cannot be integrated unconditionally with other equipment if it is not produced in accordance with the JDF standard.

As a result, the problem has become apparent that post-press processing equipment that is compatible with the JDF process must provide basic material conditions that enable device interconnection. The industry term is called the JDF interface.

This term very accurately describes the way and nature of the interconnection of devices. It is similar to the interface cards widely used in the computer industry, such as display cards and network cards. It requires active and passive exchange of information with the outside world, that is, from the process control The center's instructions, and can feedback the current status of the equipment execution instructions and production tasks to the control center.

JDF interface has its own particularity compared with interface cards with strong versatility such as display card and network card. First of all, the JDF interface is very specialized and must accept the parameters required by the JDF standard, so that the postpress equipment can accurately determine whether the input resources meet the equipment and process requirements and generate output resource information for use in subsequent processes. . Only in this way can the device interconnection be realized in the true sense, and the capabilities of the JDF post-press processing equipment should be brought into full play. Secondly, the JDF interface should conform to the communication specification defined by the JMF format (the sister format of the JDF) and be divided into two forms of information communication within and outside the system. Therefore, not only the regular communication function of the interface card but also the professional content must be considered. The format of the job document that meets the standard must be defined, and the JDF interface of other devices must be readable.

It must be noted, however, that the JDF standard is not a device manufacturing standard. It is at the macro level and only regulates printing processes, equipment manufacturing and system development. To date, there has not been a macro-level standard that deals with the details of equipment manufacturing and system development. For example, the ICC standard defines four color gamut mapping methods, but only some of the principles need to be further refined by a developer of the color management system, such as designing a conversion algorithm from the color data RGB to the CMYK color space. It can be seen that the formulation of the JDF standard does not solve the specific technical details of the equipment manufacturing, nor can it solve the specific technical details of the post-printing processing equipment JDF interface, but only provides technical principles and framework.

In summary, the development of post-press processing equipment has nothing to do with print quality, which makes the issue relatively simple. In addition, if you do not consider the compatibility with the JDF process, then there is no problem, just consider the general functional elements of the device. However, if you want to produce post-press processing equipment that is compatible with JDF flow, then you must develop the JDF interface at the same time. It is worth noting that the development of this interface is not arbitrary and should meet the basic requirements of the JDF standard in order to interconnect and communicate information with other JDF-compliant devices.

Basic development principles

Before discussing this issue, we must first understand the difference between digital equipment and analog equipment.

The so-called digital device refers to digitally controlled devices or hardware. Its important reference indicator is whether it can connect with computers and exchange information. Analog devices also need to be controlled. Only the control mode is different from that of digital devices. Most analog devices control the device through switch boxes, remote controls or the like.

As mentioned earlier, the main feature of digital devices is that they can be controlled by computers, but the essence or control of computer control lies in software. Anyone who buys and uses a scanner knows that using a cable to make a physical connection between the scanner and the computer is certainly not enough. You must also install the scan-driven software before you can direct the scanner to work.

Return to the JDF interface problem. It is assumed that the equipment manufactured by the post-press processing equipment manufacturer has a JDF interface, and that this interface can be controlled by software after being connected to a computer. Such a device must be a digital device and must be compatible with the JDF workflow. It seems that the problem has become more and more complicated, but in reality it is not the case. After all, digital control reflects the essential properties of the JDF interface. Of course, whether or not it can be controlled by a computer is only a matter of nature. The nature of the problem is how the post-press processing equipment is controlled or controlled, because the implementation can be varied. From the point of view of actual needs, JDF interface does not need to be provided with a full-featured driver software like a scanner. Considering that post-press processing equipment often only needs to provide simple functions, there is no need for hardware and software separation methods like scanners, and they can be integrated together, for example, digital control functions can be solidified into electronic circuits.