Humidity Control in Printing and Graphic Arts

Paper has hygroscopic properties, that is, its moisture content varies in accordance with the humidity of the surrounding environment.

Moisture control is very important in the printing process as excessive moisture can cause jams in the press and heating on the rollers during production.

Adversely, if an environment becomes too dry, it can change the physical properties of the paper; contraction of dimensions or ripples on the surface, since these are determined by moisture content.

With a humidification system in place it is possible to maintain a constant RH suitable for the product, therefore protecting quality and contributing to increased productivity.

Static electricity can often develop on dry paper that passes through a printing machine with low relative humidity.

When the RH drops to 40%, the static electricity will increase. This causes the paper to stick and break, interferes with smooth running and makes stacking a problem.

Static load is the most common cause of disruption in continuity of work in the printing process.

Screen printing is a technique used to reproduce documents and images onto any material. It involves transferring an ink, through a mesh, which is tensioned in a frame.

The drying phase of the process is of vital importance, as it determines the level of adhesion and therefore, the durability of the finished, printed product.

Fisair has created specific humidification equipment which can maintain the correct RH levels required for your space. This allows improved quality, contributing to greater productivity.

Isothermal Humidification:

This process involves the introduction of water vapour, generated by boiling water, into the environment.

Adiabatic Humidification:

This involves the direct evaporation of water into the air, without the input of external energy.

Application References

Fisair works closely with multinational Tetra Pak to maintain the moisture levels in its production and storage areas.

The systems used are diverse, and depend on the suitability of each internal application: Adiabatics by pneumatic atomization and Isothermal by submerged electrodes.

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