For this article, we would like to present some of the most important pieces of equipment in the graphic industry sector from Inelme and, more specifically, in the flexography sector: including the doctor blade.
The doctor blade was born from the evolution of the flexographic inking system composed of rubber and anilox rollers working in contact to dose the ink delivered by the latter. The replacement of the pressure roller (rubber) with a system, first single blade and then double blade in closed chamber, was a breakthrough for the quality of flexographic prints.
Manufactured in different materials, aluminum, stainless steel or carbon fiber, its main objective is to regulate the amount of ink delivered by the anilox—enabling the production of uniform colors at any printing speed and also offering the possibility of very low contributions compared to the previous system. Therefore, it became indispensable in color selection prints.
The doctor blade consists mainly of three essential elements: the body, made of different materials, the blades, one of entry and the other of exit, of steel or plastic, and the lateral shutters that keep the ink inside the chamber and that are mainly fabricated of foam or rubber depending on the needs (printing speed or duration of the job to be printed. Foam ones are especially suitable for short runs, while rubber for long runs.
The most important advantage when using a doctor blade in the flexographic printing bodies is the uniform filling of the ceramic anilox roller sockets, since it makes the prints exceptional and eliminates the problem of color increase by increasing the printing speed of the old printing systems with a rubber pressure roller that allow more ink to pass with increasing speed.
What should be taken into account at the time of choosing a doctor blade?
• Easy to change blades. Since it is necessary to renew them from time to time, whether they are steel or plastic, this is a very important factor. It is essential that it is not necessary to use tools for this task versus levers; whereupon with a simple hand movement one can release, change and lock the blades.
• Resistance and lightness. It indispensable for a doctor blade to be very resistant to bending to avoid defects in the supply of ink in the central area of the anilox. It should also be lightweight. Normally it’s made of aluminum, and it is important to pay attention to the anodizing applied to prevent corrosion.
• Hermetic closure. These blades have a sealing system on the sides called shutters, which prevent ink leaks and are preferably manufactured in elastomers resistant to the chemicals of the ink to be used.
• Easy assembly and disassembly. The doctor blade must be able to be assembled and disassembled quickly from the printing body (in the same way that with the blades it is important to not make it necessary to use tools) and it is advisable that with a simple turn on itself of 90° it can remain in an upright position to allow the change of blades mounted on the printing body.
Are you interested in knowing more about the doctor blade? Get in touch with Inelme and our professionals will answer all your questions. You can reach them on the phone number +34 961 47 10 85 and by email at firstname.lastname@example.org.