The printing industry uses diverse technologies to produce a wide variety of printed materials. From lithography and flexography to screen printing, there are many different printing processes which share some common production and environmental challenges. Among these are the wise use of energy, maintenance of good indoor air quality, and year-round control of temperature and humidity in the facility.
Paper, the principle material used in printing, is hygroscopic and very sensitive to variations in the humidity of the surrounding air. Problems caused by expansion and contraction of paper in the printing are all related to high humidity conditions. Uncontrolled humidity results in:
- Weak Stencils
- Pinholing
- Sticking Photopostitives
- Lengthened Drying
- Poor Imaging
Various areas in the printing process require humidity and temperature control to produce perfect results.
Platemaking
Maintaining constant dry bulb temperature and relative humidity in platemaking room provides a plate at a known control point.
A condition of 24 to 27°C and a RH of 45% is optimum.
Additionally, special attention should be given to air cleanliness and ventilation in platemaking to eliminate chemical fumes and dust errors in the plates.
Printing
The three basic methods of printing are as follows:
- Letterpress (relief printing): ink is applied to a raised surface that does the printing.
- Lithography (planographic printing): the inked surface that does the printing is neither in relief or recessed.
- Gravure (intalgis printing): the inked areas are recessed below the surface.
In digital printing the moisture content can affect the toner adhesion, paper jams and the fuser roller temperature.
In offset it can affect the interaction between the ink and the press, the paper and the press, and the ink and paper.
Inkjet is affected by many of the same issues but is even more susceptible to dot gain or ink spreading, drying delays and ink show through.
Recommended temperature and RH conditions are 25 to 27°C and 43 to 47% as ideal conditions.
Paper Storage and Shipping
Paper is normally received at the printing plant in moisture proof wrappers. However, once the paper is exposed to temperatures substantially below the room temperature, it rapidly absorbs moisture from the air with resulting distortion.
Bry-Air Solution
Adsorption dehumidifying equipment manufactured by Bry-Air for independent humidity control with provisions for cooling provide an ideal solution to handle the moisture menace in the printing industry. The Bry-Air compact dehumidifier provides a simple and cost-effective solution to humidity control. It also ensures highest moisture removal through continuous ‘physical adsorption’ by MSFM and are CNC fabricated with Powder coated finish, Bry-Air Dehumidifiers range from Compact units that can be installed under false ceiling to Engineered Systems
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