Printing is a reproduction process in which printing ink is applied to a printing substrate in order to transmit information (images, graphics, text) in a repeatable form using an image-carrying medium (e.g., a printing plate). The image carrying medium is the storage element (i. e., […]
Monthly Archives: October 2011
Printers have known for a long time that some aqueous coatings make an excellent primer for offline UV jobs, but more and more “specialty” jobs require foil stamping, gluing [pocket folders], ink jet [address labels], or the ability to go through a laser printer. Ultraviolet [UV] Coating Almost every high-end […]
Printing over aqueous coatings
RUB RESISTANCE – When printed materials rub against machinery during finishing operations or against each other during shipping or handling, the printed surface is subject to a rubbing action that tends to wear or scratch the printed surface. Water-based coatings applied over the printed surface help to improve the rub […]
AQUEOUS COATINGS-Part 2
Aqueous coatings ( water-based varnishes) are used from commercial printers for a long time giving benefits to final product and to printers in a way of higher gloss of printed product, better rub resistance, smoother feel (elimination or reduction of spray powder), and faster handling of the printed work. Basic […]
Aqueous coating-Part 1
Although printing blankets may appear similar on the surface, there are a number of factors to consider when selecting the proper blanket for your press and printing application. Printing blankets have many physical properties that vary depending upon the manufacturer and the blanket style. Characteristics such as: print quality release […]
Printing Blanket Characteristics
There are four basic solvent types for washing up the press. In most cases, the same wash can be utilized for both rollers and blankets. Water-miscible washes – the most popular type in the industry, water-miscible (or mixable) washes can generally be blended with 20%-50% water. Featuring moderate drying speeds, […]
Solvents for Washing Offset Press
The ability to deink paper – in other words, to separate ink and coatings from it – is crucial for sustainable recycling of it. Good deinkability is a prerequisite for using used paper to make graphical papers and hygienic paper products. Effective processes are available today for removing aqueous coatings […]
Deinking of Paper
Some of the pigments used in ink contain metallic substances which are harmful to human health and the environment such as cadmium, chromium, lead and mercury. Conventional printing inks are petroleum – based and used with alcohol-based solvents. As alcohol and petroleum evaporate Volatile Organic Compounds (VOCs) are emitted. VOCs […]
Ecological Printing – Inks and Coatings
Problem:Solids appear to lack density Cause: Improper ink/water balance Improper concentration of fountain solution Non-uniform dampening Loss of image area Improperly set form rollers Solution: Adjust to proper ink/water balance Adjust fountain solution to proper pH/conductivity (pH 4.0-4.5) Clean brushes, flicker blades, etc; replace if necessary Adjust form rollers to […]
Color Too Weak
Problem:Part or all of image on plate does not take ink. Cause: Fountain solution too acidic Excessive gum in fountain solution Plate cleaners and/or scratch removers have dried on plate image Fountain system contaminated by detergent Excessive fountain solution in ink Improperly developed plates; gum adheres to image area […]