for CtP Imaging Systems
Technical Acceptance and Assessment
Which activities does the quality assurance of the printing plate production comprise?
The tests that do not involve measuring technology primarily focus on the visual assessment of control elements and documentation tasks. These are mainly found in the process check.
Our services: for your Company:
We check the imaging unit and provide suitable test forms for the purpose. In addition to the imaging unit, we also assess the output workflow (with the CtP test forms), the pre-warming oven, the developer and the register punch. You receive a test report featuring a detailed analysis of the test forms.
As an optional service, we can also test the output workflow for PDF/X conformity, the tonal value transfer during printing form production and in the printing stage the printing press settings.
Perfect data quality
How often should an audit be carried out?
The frequency with which the tests are carried out can vary. A distinction is made between constant (on every printing plate) and regular tests (defined testing intervals, specific occasions such as a change of developing fluid).
Quality assurance has previously involved mostly constant checks supplemented by regular checks , . The concept of quality assurance in these guidelines takes account of advances in technology and shifts the emphasis of the tests onto regular checks.
The gathering, assessment and documentation of the process parameters is declared as a process check. The steps required to check printing plate quality are referred to as a quality check.
Here is what you should consider when choosing a type of printing plate
the constant shortening of production times mean that systems need to deliver reliability that their users can depend on.
1. There are only a few makes specifically for CtP exposure
Essentially, when imaging conventional printing plates, it must be remembered the same results cannot be achieved with all types of printing plate during imaging in CtP systems. Despite the same categorisation (“conventional printing plate”), there are only a few printing plate types that have been adapted or developed especially for imaging in CtP systems. On closer inspection of these printing plate types that have been developed or adapted especially for imaging in CtP systems, the term “conventional printing plate” should be regarded as questionable – but this is what has become established on the market.
2. Only 29% of plates available are specifically designed for imaging in CtP systems
As a survey carried out as part of a FOGRA research project of 59 of the conventional printing plates currently available on the market has shown, only 29% of the printing plates available have actually been developed or adapted for imaging in CtP systems.
3. 71 % represent conventional printing plates for conventional frame copying
The remaining 71% (which also include the printing plates for which there was no manufacturer’s information regarding suitability for CtP imaging) are conventional printing plates for conventional framework copying.
Therefore it should be pointed out that there are differences between the individual types. This can relate to the roughness depth of the aluminium substrate, for example, the homogeneity and consistency of the copying layer or even the matt finish of the surface, of the sort usedby some manufacturers to avoid undercutting in copying frames. Given the modern-day demands on printing production, suitability is therefore a criterion that must be checked very carefully.
3 points to consider when
choosing development chemicals
It is always recommended that the system developers provided by the printing plate manufacturer or approved development chemicals from third-party suppliers
be used. This is because, in addition to the basic development capacity of a printing plate in a developing fluid under normal practical conditions, the stand time also plays a role – namely the time during which the chemical reaction between the printing plate and the developing fluid remains the same and consistent output results are produced.
If the combination of printing plate and developing chemicals is unsuitable, the chemical system can become unstable unexpectedly, despite an initially problem-free output result, the consequence of which is faulty printing plate development.
Acceptance by a professional inspector from an independent company such as IPM Müller und Resing GmbH (IPM) creates trust for both the buyer and the seller.
Record and remove defects
Acceptance involves an objective check using measuring technology of the contractually agreed characteristics and very quickly flags up any defects in the installed system. It is only once these defects have been remedied that the final instalment should be paid to the seller and the guarantee period for the CtP system should begin.
Acceptance can also be regarded as a training opportunity for staff. They are familiarised with the quality checks that need to be carried out on a regular basis. As a result, problems and faults are recognised and eliminated quickly in the long term. The proof of quality is documented in a detailed and extensive acceptance test report and certificate.