What Is a Pile Turner?
A pile turner, also known as a paper turner or paper flipper, is a type of automated auxiliary equipment used in the printing and paper processing industries. The world's first pile turner was introduced in 1976; its original design purpose was simply to replace manual labor in performing the arduous task of turning paper stacks. After nearly half a century of technological evolution, modern pile turners have evolved from simple turning tools into comprehensive paper stack handling platforms that integrate multiple functions, including turning, air blowing for dust removal, vibration for paper alignment, drying and deodorization, and static elimination.
Core Functions
Paper Stack Turning
Paper stack turning is the most fundamental function of this equipment. In double-sided printing scenarios, paper stacks that have been printed on one side must be turned 180 degrees before the other side can be printed. Traditional manual turning is extremely labor-intensive and can easily leave smudges on the paper surface, affecting print quality. The automatic pile turner can complete the turning of an entire stack within minutes, freeing employees from this arduous physical labor.
Air Blowing for Dust Removal
Air blowing for dust removal is a critical pre-treatment step in the pre-press process. The high-pressure air blowing system on the pile turner removes impurities such as paper lint, paper scraps, paper dust, and printing talc. When used before printing, this process improves the surface quality of the paper to be printed, reduces the likelihood of double-sheet feeding, increases press speed by 3% to 5%, and boosts yield by 2% to 3%. When used after printing, it removes printing powder, accelerates ink drying, and reduces odors caused by ink solvents-which is particularly important for food packaging printing.
Vibration-Based Paper Alignment
Through the synergistic action of a vibrating platform and high-pressure airflow, the pile turner can align an entire rack of paper in a single pass. For thin and large-format paper, models equipped with a stepless frequency-modulated vibration system deliver exceptional paper-alignment results. When combined with high-pressure airflow at the tilted position after turning, the edges of the paper stack can be aligned to a precise 90-degree angle, providing neatly aligned stacks for subsequent cutting and die-cutting processes.
Static Electricity Elimination
Some high-end models are also equipped with an ionizing air blow system that neutralizes static electricity on the paper's surface. Static electricity is a common cause of paper sticking and double-sheet feeding during high-speed printing and processing; eliminating it helps improve production stability and yield.
Application Scenarios
Pile turners are suitable for multiple production stages, including pre-press, post-press, transfer stations, and before cutting and die-cutting. Sheet-fed printing plants in Europe and the United States are generally equipped with several pile turners. In the prepress stage, they are primarily used for paper cleaning and preparation for double-sided printing; in the postpress stage, they are used to remove dust, accelerate drying, and prevent quality issues such as paper sticking and back-side soiling. Some machines also feature a pallet-changing function, which allows factory-supplied wooden pallets to be replaced with system pallets for integration into fully automated production lines.