Patent Application
20070253027
The accompanying drawings illustrate various embodiments of the present invention and are a part of the specification. The illustrated embodiments are merely examples of the present invention and do not limit the scope of the claims.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.
A digital press system as described herein typically includes a Digital Front End (“DFE”) and a press. In general, the Digital Front End prepares the digital image data for use by the press and then transmits the data to the press where the actual printed product is produced using the digital image data. As described above, the DFE typically rasterizes the digital image data to prepare the data for use by the digital press.
The present specification describes a system and method for Variable Data Printing in which the variable portions of the document are merged on the digital press with a previously-rasterized template containing the static portions of the document. As a result, the Digital Front End is required to rasterize and transmit a much lower volume of data to the press, thereby minimizing the demands on the Digital Front End and the connections between the Digital Front End and the press while still maximizing the productivity of the digital press.
As used herein and in the appended claims, the term digital commercial printing will refer to printing conducted on a commercial scale as opposed to digital printing performed with a personal computer and a connected or networked digital printer. As used herein and in the appended claims, Variable Data Printing (“VDP”) will refer to a print job in which a document is printed repeatedly, where the document includes static portions that remain the same from print to print and variable portions that are changed from print to print. The variable portions can be changed to customize or personalize each print of the document.
In the past, Variable Data Printing has been performed by merging a database with a template at the source level. The database contains all the data for the variable portions of the document. Thus, the variable data for each document is pulled from the database and added to the appropriate portions of a template which contains the static portions of the document. Consequently, a number of separate individual electronic documents is created, each containing both the static template and one set of the variable data from the database. The number of such documents created will correspond to the number of sets of variable data in the database.
This merge occurs at what is known as the source level, meaning that the documents produced are in a natural input format, such as Personalized Print Markup Language (PPML) or Portable Document Format (PDF). The template may be stored in the same natural input format prior to the merger. The variable data may also be stored in the database in the same natural input format prior to the merger or may be converted into the natural input format as part of the merger process.
The resulting stream of documents, each containing both the static template and a set of variable data, is then processed by one or more Raster Image Processing (“RIP”) engines. As described above, multiple RIP engines may be needed to produce rasterized image data at or above the rate that such data is used by the imager of the press. After each individual instance of the document is rasterized or “RIPed,” it must then be transmitted to the digital press. The digital press receives the series of documents and prints each to produce the desired hardcopies, each including both static and variable elements.
As noted above, this system may present difficulties as the DFE attempts to keep up with the imager of the digital press. The potential bottlenecks have traditionally been dealt with by: (1) using multiple RIP engines to rasterize the VDP documents in parallel so as to decrease the time required to rasterize all the documents in the batch, and (2) using expensive network hardware between the DFE and the press to maximize the transfer rate of date from the DFE to the imager of the press.
The present specification instead splits the task of VDP between the DFE and the press to avoid the potential bottlenecks that have occurred in previous systems. As described herein, a VDP static template document is processed and rasterized by the DFE without any variable data included and then sent to the press for storage as reusable data. The DFE then only need rasterize the variable data portion of the desired documents during the print run and transfer the rasterized variable data documents to the press for merger with the static template and printing.
As used herein and in the appended claims, the term “static template” will refer to a VDP template that contains the data which does not change, or is static, from print to print. In the static template, the portions or fields that are reserved for variable data may be left blank. As used herein and in the appended claims, the term “variable template” will refer to a template that corresponds to, and is subordinate to, the static template. In the variable template, the areas that correspond to the static content of the static template are left blank, while the areas that are to contain the variable data are so designated.
The relationship among these various documents and document templates is illustrated in
In contrast, the variable template (132) is blank in those areas that correspond to the static elements (135) of the static template (134). The variable template (132) has fields or areas (133) that are designated for the placement of variable data. In general, these fields (133) are located in areas corresponding to the blank portions (137) of the static template. However, in some embodiments, it may be the case that variable data is to be overlaid or superimposed, partially or completely, with static elements in the static template (134), in which case, the field (133) of the variable template (132) would overlap, partially or completely, with a static element (135) in the static template (137).
To produce a desired VDP document (136), a set of variable data (130) is taken from a database. The set of variable data (130) includes print elements (131) that are to vary from print to print. The variable print elements (131) may be any document elements, including, but not limited to, text, pictures, graphics, titles, headers, etc. The variable data (130) is used to populate the fields (133) of the variable template (132). As described below, the populated variable template is then rasterized and sent to the digital press.
On the digital press, the rasterized variable template is merged with the static template (134) and then printed as a completed VDP document (136). With each document printed, a new variable template, populated with different variable data, is received and merged with the static template to produce a customized VDP document (136).
This process is further illustrated in
A database is also prepared (step 122) that contains the variable portions of the VDP documents to be produced. The database can be prepared before, during or after the preparation and rasterization of the static template.
Once the database of variable data has been prepared and is available to the DFE, the print run can begin. The DFE will access each set of variable data and merge that variable data with the variable template (step 123). This produces a stream of documents, each being a copy of the variable template populated with a different set of variable data. As noted above, the portions of these documents corresponding to the static elements of the static template are generally blank.
The documents are then rasterized (step 124) by the DFE. Because a significant portion of the documents are blank, corresponding to the static elements of the static template, the demands on the RIP engine(s) are minimized. Essentially, only the variable elements for each VDP document need be rasterized during the print run.
The rasterized documents are then transferred to the digital press (step 125). Each document may be transmitted as it is rasterized.
The press receives the rasterized documents, each being a copy of the variable template populated with a different set of variable data, and merges each such document with the static template (step 126). Additional details about the merger of the incoming documents with the previously-rasterized static template will be given below.
The ongoing merger of the incoming documents with the static template produces a new stream of VDP documents, each containing the static elements of the static template and a set of variable elements. The documents are then printed (step 127) by the digital press. The result is a print run of VDP documents each of which is customized by the variable data while containing static elements that do not vary from document to document.
As shown in
The static template (114), absent the variable portions, is prepared by the DFE (101) and is then transmitted to and stored on the press (102). In the example of
Consequently, as explained above, only the variable portions of the document need be processed and rasterized by the DFE (101) and transferred to the press (102) during a print run. The press (102) then merges the incoming variable data with the rasterized static template (118) to produce the desired series of customized VDP documents.
As described above, the variable portions of the VDP documents are prepared and stored in a database (110) which is accessible to the DFE (101). The variable portions of the VDP documents may be created using existing database merge technologies such as the PPML Templating Language (“PPMLT”) and a PPMLT template. In the example of
The PPMLT template element (112) contains only those areas of the static template (114) that were meant to be variable. Instructions for populating those areas from the database (110) may be provided, for example, by appropriate Extensible Stylesheet Language Transformations (“XSLT”).
Referring to
This stream of PPML documents is then processed through the PPML processor (113) and rasterized by the Raster Image Processing (“RIP”) engine (115). In
The rasterized VDP documents are then transferred to the press (102) as described above. The press (102) then merges the PPML documents with the static template (118). This may be done, for example, by the press (102) simply copying each variable PPML document onto the stored static template (118) using a transparent mode such that only those areas with content in the variable PPML document overwrite the template (118). This operation is performed by a copy engine (116) of the press (102). The resulting document is then ready for printing using the normal press print path.
By storing a previously rasterized template document on the press, communication time between the DFE and the press is minimized. The process of rasterizing the variable PPML documents is decreased due to the large amount of non-varying data in each document that is represented by the static template (118) and that does not have to be re-rasterized with each document as in previous systems. Additionally, because the PPML documents contain only the varying data, the rasterized PPML documents can be significantly compressed further improving communication speed between the DFE (101) and the press (102). Also, since merging the database with the stripped down variable template is done in the DFE (101), different merge technologies can be employed without affecting the press software.
The principles described herein may be implemented, for example, in an Indigo Digital Printing Press by Hewlett-Packard Co.
The preceding description has been presented only to illustrate and describe embodiments of the invention. It is not intended to be exhaustive or to limit the invention to any precise form disclosed. Many modifications and variations are possible in light of the above teaching.
