High end inkjet printers are increasingly addressing commercial print and high-end mailing markets, where print quality and consistency are paramount. Inline quality control systems can assure high print quality and additionally provide a quicker start-up and fewer manual interventions. The focus of this overview is on continuous feed inkjet presses, as the nature of these devices makes it hard “to pull a sheet” for off-line checks. Accordingly, being able to check quality inline is even more important.  While in-line quality control systems are frequently touted, I found it surprisingly difficult to get details on the specs and functionalities. The overview is mainly based on recent discussions I had as there are almost no technical specifications published.  Inline systems generally have three components: A camera or light sensor, a server for processing data, and software. The first is usually fixed for a given press and often included as a standard on the top-quality presses. Data processing speed depends on the amount of image verification required and a choice of servers can be available, possibly with upgrade options. Software is critical for the functionality and quality of the system. Often certain functions are chargeable options. The good news is that they can be added later, and functionality can even be improved in future releases.  Most vendors offer a choice of integrating 3rd party solutions in addition to the internal vision system. Especially if the internal system does not offer sufficient functionality (e.g., full image content check versus a PDF) a 3rd party system might. This usually means a higher investment and less integration into the press DFE, however. 

Canon

Already with the ProStream 1800 Canon introduced the latest inline quality control (IQC) system, a high-performance camera system to check the complete web width. It is also offered on the new ProStream 3000 Series and is included as a standard nowadays.  IQC consists of a camera, server, and software. Measurement is after drying, which allows for a precise measurement of the end results. IQC has two main features: NAC (nozzle activity control) and nUC (nozzle Uniformity Compensation). The IQC performs an ongoing activity control by checking a special test pattern (which is about 30 cm wide) every 100 to 200 m of print. Once a nozzle problem is detected, the press will automatically correct itself, either by nozzle compensation or with a refresh page/cleaning procedure. Also, colour uniformity compensation to smooth out colour variations can be performed. The nUC is a nozzle based method to compensate for density per color and graylevel. It will be performed once when setting up the press. It is possible to do the compensation on a standard reference paper or specific substrates. The IQC can also help in linearisation, which is only needed after a head change according to Canon. There is also an open interface to give the image data to a 3rd party solution for a full image content check.  Building on the IQC it is planned to offer an advanced printhead health analysis to predict any nozzle issues to be able to correct them before print problems arise.  Recently, the sheet-fed VarioPrint iX Series received a new quality control system with the release 4.3. (made public in March 2023), which is capable of scanning every sheet. 

HP

HP launched its latest CF inkjet product line in 2022 with the PageWide Advantage 2200. With the increased speed in top quality mode since Hunkeler innovationdays 23 the press also got more attractive for quality-conscious customers.  As a standard, the press has an onboard vision system termed HP Color Quick Vision system. It is utilizing two page-wide cameras and a spectrophotometer, making HP the only vendor with a spectrophotometer on board as standard.  With the camera system, linearisation of the heads and Jet-out/nozzle health can be checked. A nozzle-health check is performed at start-up on a test pattern and during printing directly in the printed image. With the spectrophotometer the system can also check density and colour.  With the spectrophotometer the vision system has all the ingredients for an on-press colour profiling. This is planned for Q3 2023. 

Kodak 

With the Prosper Ultra 520 Press Kodak is offering a continuous feed press for high quality, commercial print. Unlike most other vendors Kodak does not offer its own system. The company can integrate 3rd party solutions like Videk for stitching, register and visual accuracy. Colour profiles are created off-line.

Ricoh

In 2021 Ricoh announced the Ricoh Pro Scanner (RipSO), a page-wide quality control system as an option for the Pro VC70000 and Pro VC60000. Now it is also available for the VC40000.  RipSO is based on the Hunkeler WI8 web inspection system, however, the user interface is fully integrated into the press DFE UI. It has the full functionality, except comparing the printed image to the image file. According to Ricoh it is leveraging advances in artificial intelligence (AI) and machine learning (ML) to close feedback loops. RipSO can detect Jet outs during operation. Uniformity and alignment can be identified at start-up, scheduled, or manually by the operator. It is possible to define tolerances when continuously checking during print. The operator can decide whether to react and how to remedy the problem. With the SmartStart capabilities cleaning and start-up procedures can be automated and run unattended.  The CIS scanner included could be used for density measurements, however for colour management tasks a test print needs to be created and scanned offline. 

Screen

Screen has been a company offering in-line quality control early on with the Jetinspection system. The system has been improved over the years and now version 3.0 is on offer.  There are several tiers of functionality with the Jetinspection system:
  1. Linearisation of heads, including density uniformity, nozzle clogging checks and printhead alignment at start-up or paper change. 
  2. Nozzle check and real-time monitoring
  3. Evidence solution, that provides a proof of print and checks for numbers or codes on the page
  4. Full page inspection, including variable data against a digital master
While tier 1 is standard on the TruePress 520HD, the following tiers are software-enabled options that are based on the scanning hardware installed. An upgraded server might be needed as well. Tier 3 and 4 also have an option for storing all print image data. The nozzle check is performed on special check patterns inserted before, after, or at certain intervals within a job. Accordingly, the system can detect whether a nozzle failed during a job. The system also captures the full print image every 10 seconds and displays it to the operator screen for inspection.  Jetinspection is not used for density measurements or colour management. Recently Screen announced MYIRO, an automatic colour-calibration system from Konica Minolta Sensing. The software, combined with an auto-scan spectrophotometer, enables much faster and easier colour management and calibration. However, MYIRO is not an inline solution and printed samples have to be scanned offline. MYIRO is now shipped as standard on new 520HD presses.

Putting it to practice

Although inline vision systems are important, there is little comparability among systems due to missing specification details, documentation and lacking standards. Prospective buyers should inquire in detail about what they are getting – as a standard or as a chargeable option. It should be asked as well in detail, how set-up procedures are shortened, for example, what kind of print elements are measured, and how issues are reported and fixed. It is worth checking the experiences of existing users when there is a chance. In general, I would strongly recommend investing in in-line quality control systems for any print system. I already discussed the drivers in a previous article. For ROI calculations keep in mind that missed deadlines, unhappy customers, or emergency fixes in production are costly. Also, staffing can be reduced, and repetitive tasks avoided through press automation. As mentioned, there is too little technical information on those efficiency critical systems, therefore I welcome all feedback on the colour and quality control options in the listing above. The topic will be visited again in the future.