Digital impositioning apparatus

Details Digital impositioning apparatus Digital impositioning apparatus

1998-08-21

2002-05-07

Wallerson, Mark (Department: 2622)

Facsimile and static presentation processing

Static presentation processing

Detail of image placement or content

C358S001900

Reexamination Certificate

active

06384932

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to digital impositioning apparatus, and specifically to a digital impositioning apparatus for performing digital impositioning in Plate Making/Printing process using digital data output from Prepress process.
2. Related Art Statement
As known, Design process, Prepress process and Plate Making/Printing process are required to complete planning contents ordered by a client as printed matter. Created in Design process is a mechanical designed along the planning contents. Created in Prepress process is a film in which pictures, lines, character strings are arranged based on the mechanical and laid out. In Plate Making/Printing process, impositioning based on the film is performed to make a printing plate, and then printed matter is completed by printing.
In these processes, data processing from Design process to Prepress process has been changed from analog processing to digital processing represented by DTP (Desk Top Publishing) due to the recent widespread use of computer technology and various prepress processing software, allowing rationalization of operations. This rationalization allows designing and editing on the data digitized by DTP processing, and thereby it is possible to output digital mechanical data. In Prepress process, based on the above digital mechanical data, digital operation processing as required such as Prepress process (Trap processing and the like), RIP (Raster Image Processing) and the like after arranging digital data of pictures, lines, and character strings is executed to obtain digital page data, and a film of a prescribed size and color proof are outputted.
On the other hand, in Plate Making/Printing process, the following processing is performed in an analog fashion after receiving the film outputted from Prepress process.
Performed first is impositioning such as joining of the films received from Prepress process (different films are joined so as to be structured on one printing plate) and the like. Next, after superposing the joined films and an unexposed printing plate, exposure processing is performed to expose pictures, lines and the like on the printing plate. Then, the plate after this exposure processing is set in a printer to print on a printing paper.
After the above described operation, printed matter is completed. However, practically, there are cases where ink density of the data on the printing plate for printing (pictures, characters, tints, and the like), weather conditions (temperature, humidity and the like), secular deterioration, quality of printing papers (elasticity and the like), or the like causes fine displacements of positions of each separation (Y, M, C, K and special color) of the printed matter or partial interference between colors (inks). Furthermore, there are cases where changes of total balance in tone of the printed matter, the needs from the client, or prepress mistakes occurs. These factors often perform re-impositioning by another fine adjustment of data positions and tone on the printing plate before the final printed matter completes.
Among re-operations of the above impositioning, fine adjustment of the data positions on the printing plate is called offset adjustment, being performed by re-joining the films. On the other hand, fine adjustment of tone of data on the printing plate is called exposure adjustment, being performed by masking a page data area or a component (pictures, characters and the like in a page) area in a film at the time of re-exposure on the printing plate to partially change exposure time.
As described above, data passing from Prepress process to Plate Making/Printing process still uses a medium, that is, a film (refer to FIG.
22
). In this way, one of the reasons why films are still used as a medium is that Prepress process and Plate Making/Printing process are independent in most cases (that is, Prepress process and Plate Making/Printing process are processed by different companies in most cases). Another reason is that use of films can clearly differentiate operations of Prepress process from operations of Plate Making/Printing process, thereby advantageously defining a share of responsibility. Furthermore, in Plate Making/Printing process, it is possible to perform impositioning under bookbinding rules so as to finish one piece of printed matter with correct pagination when folded based on right-open or left-open. Therefore when correction of the printing plate and the like occur, problems can be advantageously solved only in Plate Making/Printing process.
However, it is impossible to achieve reduction in a process between Prepress process and Plate Making/Printing process as long as a film is used as a medium, and also it is impossible to achieve reduction in prepress costs because the inconvenience of film making and film costs always occur.
Therefore, in recent years, a method called CTP (Computer to Plate) is thought as a method, not through the medium of a film between Prepress process and Plate Making/Printing process, of cutting/rationalizing the process therebetween . A conventional processing system using this CTP method is shown in FIG.
23
. In the CTP method, impositioning originally included in Plate Making/Printing process is included in Prepress process, and processing up to impositioning is performed in digital operation processing of Prepress process. Then, rasterized data subjected to up to impositioning is screened to directly make a printing plate. This relieves the existence of the medium of the film between Prepress process and Plate Making/Printing process, and thus it is possible to achieve delivery time savings, reduction in prepress costs and the like due to reduction in the processing processes and removal of inconveniences of film making in Prepress process
However, when the above CTP method is used for reduction and rationalization of Prepress process and Plate Making/Printing process, no intermediate medium such as a film exists and impositioning is included in Prepress process. Therefore, in the system using the above CTP method, the following problems arise in reality for a reason such as that a prescribed correcting operation which has been possible only in Plate Making/Printing process has to involve Prepress process and the like.
(1) In a step of digital operation processing in Prepress process, a printer must be specified for use in Plate Making/Prepress process.
This is because a printing plate is directly made from operation data, and thus the operation data must have matched with the printer. Therefore, although a prepress firm has only outputted a film as a final output without necessity to specify a printer, a new problem occurs that the firm has to specify a printer before calculation processing before operation processing.
(2) It is required to provide a reliable proof method.
Like proof when a film is used as a medium (chemical proof using a film and proof by a proof machine after plate making), it is required to establish a digital proof method on digital data.
(3) When correction occurs in Plate Making/Printing process, it is required to return to Prepress process again and re-process from the rasterization.
Since impositioning is included in Prepress process, unlike a case of using a film, correction in a film unit such as that in impositioning in Plate Making/Printing process is impossible.
(4) Moving and color matching in a page unit at the time of printing are impossible.
That is because digital data after rasterization in Prepress process is created not in a page unit but being impositioned.
(5) A stable supply of reprint within a certain period of time is impossible.
In relation to the above (3) and (4), it is impossible to reprint the printing plate in Plate Making/Printing process, and it takes more time than it needs to be.
(6) Dot gain adjustment on the printing plate is impossible.
Since dots are directly exposed on the printing plate in Plate Making/Printing process based on the rasterized digital data in Prepress process, dots cannot be corr

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