Doctor Blade Composite Structure for Ink Metering
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Solution Overview
Problem
Current doctor blades, either metallic or non-metallic, face challenges such as high friction, abrasiveness, oxidation, and safety issues, while lacking rigidity and flatness, which affect their performance in ink and coating metering applications.
Innovation Solution
A doctor blade design featuring a plastics material working edge and a reinforced plastics material base body with a rigid inner layer, providing structural components of different rigidities to achieve a balance between rigidity and non-abrasiveness, while preventing oxidation and enhancing safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metallic blades are used, then rigidity and flatness are improved, but abrasiveness and safety issues worsen
Solution Approach 1:
The doctor blade combines a metallic base body (providing rigidity) with a polymeric blade region (providing non-abrasiveness). This composite structure allows the metal core to maintain structural integrity while the polymer layer contacts the printing cylinder surface, eliminating the need to choose between rigidity and safety.
Solution Approach 2:
Different regions of the doctor blade have different material properties: the base body is metallic for rigidity, while the blade region is polymeric for low friction and safety. This local differentiation allows each region to optimize its function without compromising the other.
2Object-generated harmful factors
If non-metallic blades are used, then safety and low abrasion are improved, but rigidity and flatness worsen
Solution Approach 1:
The combination of metallic base body and polymeric blade region allows the structure to achieve both safety (through polymer contact) and rigidity (through metal support), resolving the contradiction that forces a choice between these properties in single-material blades.
Solution Approach 2:
The blade region is specifically designed with polymeric material to provide safety and low friction where it contacts the printing cylinder, while the base body maintains metallic composition for overall structural rigidity.
3Ease of manufacture
If metallic blades are used, then manufacturing ease is improved, but oxidation and rust development worsen
Solution Approach 1:
The polymeric blade region is applied only where contact with the printing cylinder occurs, providing oxidation resistance and corrosion protection at the critical interface, while the metallic base body maintains manufacturing simplicity for the non-contact structural portions.
Data Source
Figure 1~3C
AI summary
A doctor blade, in particular for metering of inks and coatings from an engraved surface, has a flat oblong base body (1a) and a blade region (1c) with a working edge (5) being formed at one of the longitudinal sides of the base body (1a). The blade region (1c) is at least partially made of a plastics material (3, 4), whereas the working edge (5) is formed of the plastics material (3, 4). The base body (1a) is made from a reinforced plastics material (2, 3, 4). The opposing main outer surfaces of the base body (1a) are constituted by plastic layers (3, 4) made from a first material, where at least one inner layer (2) made from a second material having a higher rigidity than the first material is provided in between said plastic layers (3, 4). The doctor blade (1) therefore incorporates structural components of different rigidities, whereas a plastic working edge (5) is provided. This doctor blade (1) is at the same time rigid and non-abrasive. The wear debris is not harmful to the media and the doctor blade (1) provides sealing qualities. Due to the fact that the main outer surfaces of the doctor blade (1) are constituted by the plastics material the doctor blade (1) is not subject to rusting or oxidation and the safety for the user is enhanced.