Printer Head Chip Roller Asymmetry for Density Uniformity
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Solution Overview
Problem
In printers with line-type jetting heads, density unevenness occurs due to differences in jetting characteristics between adjacent head chips, leading to streak-like density issues and roller marks when boundary nozzles are used, and it is challenging to optimally arrange rollers to prevent these issues without causing further image quality deterioration.
Innovation Solution
The printer is configured with first and second head chips arrayed orthogonally to the conveyance direction, with specific arrangements of third and fourth head chips, and rollers positioned differently relative to each head chip group to minimize overlap of roller marks and density unevenness by varying the positions of boundary nozzles and rollers between head chip groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If boundary nozzles are used in the area where two head chips face each other, then density unevenness is reduced, but roller marks become conspicuous
Solution Approach 1:
The patent applies asymmetry by arranging rollers at different positions relative to head chips in different head chip groups. Specifically, in the first head chip group, rollers are arranged at a first position, while in the second head chip group, rollers are arranged at a second position that is offset from the first position. This asymmetric arrangement ensures that roller marks occur at different positions for different head chip groups, preventing overlap and making roller marks less conspicuous, while still allowing boundary nozzles to function for density uniformity
2Manufacturing precision
If rollers are arranged close to head chip ends to prevent image deterioration, then gap variation is reduced, but roller marks overlap and become conspicuous
Solution Approach 1:
The patent resolves this contradiction by using asymmetric roller positioning. Rollers in the first head chip group are positioned at a first location close to the head chip ends, while rollers in the second head chip group are positioned at a second location that is offset from the first location. This asymmetric arrangement maintains close positioning for image quality while distributing roller marks to different positions, preventing their overlap
3Device complexity
If boundary nozzles are positioned at the same location for all head chips, then device complexity is reduced, but density unevenness overlaps and becomes conspicuous
Solution Approach 1:
The patent applies asymmetry by positioning boundary nozzles at different locations for different head chip groups. In the first head chip group, boundary nozzles are arranged at a first position, while in the second head chip group, boundary nozzles are arranged at a second position that is offset from the first position. This asymmetric nozzle arrangement ensures that density unevenness occurs at different positions for different head chip groups, preventing overlap and maintaining uniformity
Data Source
AI summary
There is provided a printer including first to fourth head chips, and first and second rollers. The first to fourth head chips are arranged at intervals in a second direction orthogonal to a first direction. A nozzle, of nozzles arranged in a second head chip N and used for printing, which is positioned closest to the one side in the second direction is referred to as a nozzle A. A nozzle, of nozzles arranged in a fourth head chip N and used for printing, which is positioned closest to the one side in the second direction is referred to as a nozzle B. The nozzle A is arranged closer to the one side in the second direction than the nozzle B and the first roller is arranged closer to the other side in the second direction than the second roller.