Web Inspection: Consistent print is not always as easy as it may look

We all want the best possible quality, and with web inspection, it’s now possible to deliver an even and consistent print quality across the print run, but how does it work, and does web inspection offer you more than what meets the eye?

Before sharing some interesting takeaways using web inspection, let’s start somewhere else. Printing is by nature dynamic. Printing is about putting ink or toner on paper – and as the paper is a natural resource, the substrate itself is dynamic. Heat changes the paper. Moisture changes the paper. Transportation through the printer changes the paper. So to make even and consistent print is not always as easy as it may look!

Why web inspection?

In the past, the printing quality depended on the print operator’s eyes, and each printing company defined its standards. With CTP (Computer-to-Plate) in offset, digital print, and PDF files, standards for, i.e., colors were standardized. Today both designers and printers use Fogra, G7, and ISO standards to ensure consistency between design and print.

The printing industry has moved forward, ensuring consistent quality, and discussions between customers and printers are rarely based on opinions but on accurate measures delivered directly from the machines.

Web inspection is not new, but the quality, speed, and possibilities rapidly develop as with all technology.

Web inspection solutions consist of high-speed cameras placed in the machines combined with software/workflow able to analyze the images quickly. The images are used to compare the print with anticipated results and trigger different actions based on the result.

Before talking about the web inspection itself, let’s look at why we want to inspect in the first place. One thing is to use web inspection to ensure consistent quality, as already mentioned. Still, if you think about a printed book, it consists of numerous pages, and with the options today to print on demand, a digital printer can print a lot of different books in the same job, so what happens if pages are missing or if errors occur?

With no web inspection, customers can end up with books with missing pages or evenly flawed pages with errors, or even content from other files. So the web inspection enables the entire printing system to communicate and automatically remove faulty products from the production, which ensures a higher up-time and a consistent delivery of fault-free books/products. The communication between the printing device and the binding equipment is vital since the printer still needs to deliver the ordered books regardless of errors. Web inspection is an essential part of this flow!

IPI vs. Golden Sample

So how does a web inspection system work? Professionals refer to IPI vs. Golden Sample. A Golden Sample or Golden Template is a set of elements that the operator places on the print, which the web inspection camera will then recognize. Golden Samples works fine but requires setup time and only considers the book block’s quality based on the Golden Sample points rather than the entire page. IPI is short for Intelligent Print Inspection and is widely considered the better choice. With IPI web inspection, the production data, i.e., the PDF, is used to compare the original file’s entire printed image.

With IPI, there is no setup time, and as the entire page is measured, the web inspection catches potential errors more precisely. With faster and faster productions, variable data, and with various products produced in the same flow, web inspection has simply become a necessity.

As you can imagine, web inspection enables better quality control of the print and documents the entire production and can be used to log and track jobs. Customers constantly get higher and higher expectations on delivery time, production quality – and with digital print and finishing, web inspection is another service that secures yourself and your customers.

Reduce waste with web inspection

Web inspection is not only great for the matters described above but also to reduce waste. When you have manual processes, quality is often checked randomly and if the operator experience errors in the print often a large number of book blocks or sheets needs to be trashed. The web inspection communicates with the printing device and ensures that the machine is stopped when an error occurs that can’t be managed automatically, minimizing waste.

Waste is also minimized as digital print and finishing combined with web inspection allows printers and customers to produce the quantity needed. In analog production like offset, you will often need extra sheets to set up both the printing device and the binding equipment to ensure consistent quality in the ordered print run.

With digital print and finishing, the setup time and material needed are dramatically reduced, and you are now able to produce highly cost-effective alone from this perspective!

Considerations of web inspection

As you can imagine, Hunkeler develops and produce high-quality and fast binding equipment, and therefore web inspection is an entirely integrated part of the solutions Hunkeler offer. In the previous articles published, we have talked about digital print finishing and book on-demand – and of course, web inspection is something you will have to consider if you are investing in the new technology. If you are a customer, you can be sure that web inspection is already part of your supplier’s production setup, which will ensure even consistent quality and allow you to log and track your printed products in a significant way!

About the author

Morten B. Reitoft

Morten Reitoft is the editor of INKISH News and INKISH TV. INKISH TV is a TV-channel for and about the print industry.
Through his numerous posts and videos around the printing industry, Morten has a broad expertise in digital printing and knows both the companies and technologies behind them.