Powdering Device Pneumatic Distribution for Printing Presses
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Solution Overview
Problem
Existing powder spraying devices for sheet-fed printing presses face challenges in precisely distributing a consistent amount of anti-setoff powder due to varying powder densities caused by changing weights, leading to inadequate or excessive powder application, which can result in printing defects and environmental pollution.
Innovation Solution
A powdering device with a storage container and an appropriate-powder-amount distribution mechanism featuring a rotating powder placing member with a staircase-like placing section and scraping members to uniformly distribute powder into an air flow, eliminating pressure on the powder and ensuring a constant amount is sprayed, with optional stirring to prevent agglomeration and simplify the structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of sprayed powder is increased to prevent blocking, then blocking prevention is improved, but the surface quality of the printing product deteriorates and the environment is polluted
Solution Approach 1:
The patent changes the physical state and distribution parameters of the powder by using compressed air to atomize it into fine particles. This transforms the powder from a coarse, uneven distribution to a fine, uniform aerosol that can be precisely controlled in amount and distribution, achieving adequate blocking prevention without excessive accumulation that causes surface quality issues and pollution.
Solution Approach 2:
The patent employs compressed air (pneumatics) to carry and distribute the powder. The air flow entrains the powder particles and delivers them uniformly to the printing product surface, enabling precise control of the powder amount sprayed. This pneumatic delivery system prevents both insufficient powder application (causing blocking) and excessive application (causing surface deterioration and pollution).
2Device complexity
If the powder density in grooves is increased by weight application, then powder feeding is simplified, but the manufacturing precision of powder distribution deteriorates
Solution Approach 1:
The patent extracts the powder from the storage container and immediately atomizes it with compressed air before it can be subjected to variable weight pressure in grooves. By taking out the powder and delivering it directly through air flow, the system eliminates the groove structure entirely, avoiding the problem of variable density caused by changing powder weights while maintaining simple device operation.
Solution Approach 2:
The patent replaces the mechanical groove-based powder holding system with a pneumatic delivery system. Instead of using mechanical structures (grooves) to hold and transport powder, the system uses compressed air to carry the powder particles directly to the target, eliminating the mechanism that causes density variation while maintaining operational simplicity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device stabilizes powder distribution, preventing printing defects by maintaining a consistent powder application, reducing environmental impact, and allowing for adjustable powder amounts based on printing conditions through controlled rotational speed.
Implementation Method 1
an air flow for carrying the powder
Implementation Method 2
the powder stuffed in the grooves is transferred in such state by the friction with the peripheral surface
Data Source
AI summary
A powdering device includes: a powder placing member having a placing section on which a powder fed from a storage container is placed; a first scraping member for scraping the powder on the placing section of the powder placing member, so that a constant amount of the powder remains on the placing section; and a second scraping member for scraping off the resultant constant-amount powder remaining on the placing section, and the powdering device transfers the scraped powder with an air flow, and sprays the powder thus transferred onto a printed sheet.