Revolutionary IPI technology
IPI stands for Intelligent Print Inspection and enables a new way of performing print inspection. In general, the concept of ‘digital print image inspection’ refers to the comparison of a printed sample to a pre-defined template. The template and the sample are both images, or regions of images, that have been captured by the inspection system and are available within the system as digital data (“bitmaps”). Conceptually, print inspection can be understood as the subtraction of the sample from the template:
This means that if the sample image is 100% identical to the template image, the subtraction of the two images results in a “black” result image (no errors present). However, if the sample deviates from the template image, the resulting image shows a difference that correlates in position and extent to the printing error. This difference is analyzed by the inspection system and can trigger different actions: For example, alerting an operator, stopping the printer, or trigger a report to a database that this page contains an error and must be rejected during the finishing process.
In traditional print inspection, the operator creates the template for image matching (Golden Template). A number of features to be checked are selected on a printed page that has been found to be “good”.
IPI opens another way to create the template for image matching: Instead of having the template set by the operator, the IPI system uses the raw print data directly sent from the printer controller to the inkjet print heads. This means IPI dynamically reads this data and generates a digital image on-the-fly without affecting the printer. This dynamically generated image serves as a template for the system to compare with the print sample.
Innovative possibilities with Intelligent Print Inspection
This direct comparison of ‘what should have been printed’ to ‘what was actually printed’ without creating a golden template in advance enables completely new applications:
In transactional printing, errors in the printing of variable data can be In transactional printing, errors in the print of variable data can be detected without, for example, the address information being known in advance. Furthermore, it is possible to detect print errors in graphics and images in photo books, even if they occur only once in an entire print job.
Reduced Operator load
The demand on the operator is greatly reduced, since the necessary setup and make-ready of a golden template is no longer required. The Hunkeler Web Inspection WI8 system serves as the user interface of IPI. This means that standard functions of the WI8 can be combined with results from IPI. This is necessary for example, if in addition to the print inspection specific nozzle failures are to be detected. The IPI functionality requires a very high data throughput and places high demands on available PC hardware. Therefore, the resolution for IPI is limited to 300dpi. Meanwhile, nozzle failures usually require double the resolution (600dpi) supported by the WI8 system. Both tasks can be carried out in parallel.
Application and availability of the IPI Intelligent Print Inspection
The Intelligent Print Inspection is an optional add-on to the Hunkeler Web Inspection System WI8.
IPI is currently available for the Canon ColorStream series of printers.
Connections for other printing systems are under development.