Humidity and the printing industry


Paper printing is a complex technical process that can hardly be done by rudimentary methods. Printing houses have multiplied, purchasing more and more high-performance equipment, and customers have become more and more demanding, already knowing what their finished work should look like.


Paper rolls and printing paper are normally produced to remain in equilibrium with air at a humidity of 50 ± 5% u.R. When the humidity of the environment falls below this level, the paper loses water thus changing its shape, size and physical properties.


In a printing house where the relative humidity values are below 40%, the movement of paper on paper or other surfaces generates electrostatic charges that lead to the gluing of surfaces, attracting dust and making the paper very difficult to handle.


The paper is hygroscopic so it absorbs moisture from the air, thus changing its properties and either wrinkles due to water absorbed from the air and can no longer be used or becomes too dry. If you have experienced problems with print quality or paper jams in the copier or printer, then you can understand how changes in texture, strength or weight can affect the high-speed processing of hygroscopic materials.


All traditional, digital or offset printing enclosures are affected by moisture problems. 


A correct level of relative humidity  of 50-55% helps improve print quality, prevents paper distortion and jams in the copier, prolongs the life of printers and printing plates, and prevents  electrostatic buildup.


Different printing processes require different levels of humidity. In digital printing, the moisture content can affect toner adhesion and print quality, cause paper jams, and affect the temperature of the fuser roll. In offset, it can affect the interaction between ink and press, paper and press, and ink and paper. InkJet printing is affected by many of the same problems, but is even more susceptible to ink drying delays and ink stains.


The accumulation of electrostatic energy is dangerous for both employees and printing machines. Electrostatic charges cause a multitude of printing defects, the static field on a surface will push and remove ink particles away from the proposed paths, causing printing defects such as blurry printing or ink spills. Not only can these ink particles affect the quality of the final print, but they can also be pushed back to the printheads, which can cause clogging of the small outlet holes.


Humidifiers add moisture to the air, and the moisture in the air forms a thin protective “film” on the surfaces that serves as a natural conductor to dissipate electrical charges. When the humidity drops below 40% RH, this protection disappears and the normal activities of the employees lead to the charging of the objects with static electricity.


Condair has extensive expertise in all printing processes and projects worldwide and offers complete solutions and consulting services design, supply, installation, commissioning and maintenance, as a representative of the Condair group for Romania and the Republic of Moldova, Texco is always prepared with the most competent information and a team of professional technicians. So if you are part of the printing industry and humidity is causing you problems, do not hesitate to contact us.


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