Liquid Ejecting Apparatus Head Unit Inclination Compensation
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Solution Overview
Problem
Conventional line printers face challenges in precisely printing images due to inclination of the head unit or individual heads, leading to color shifts and banding issues caused by manufacturing and assembly errors, which result in ink being applied at incorrect positions on the recording medium.
Innovation Solution
A liquid ejecting apparatus with a head unit comprising multiple nozzles oriented perpendicular to the recording medium transport direction, equipped with a control unit that calculates and adjusts the ejection timing based on inclination information to ensure accurate ink placement, and a method for controlling the apparatus to select the most appropriate nozzle position and timing for each nozzle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of nozzles is increased to achieve higher printing precision, then the manufacturing difficulty and cost increase significantly
Solution Approach 1:
The head unit is divided into multiple heads (first head, second head, third head, fourth head) arranged in the direction perpendicular to the recording medium transport direction. Each head contains a plurality of nozzles, allowing the system to achieve high printing precision without requiring a single head with an excessively large number of nozzles, thus reducing manufacturing difficulty.
2Area of stationary object
If multiple heads are arranged sequentially to cover the recording medium width, then spaces between heads create positioning errors leading to color shifts and banding
Solution Approach 1:
Inclination information representing the degree of inclination of each head relative to the reference direction is stored in advance in an inclination information storage unit. Before printing, the control unit calculates appropriate ejection timing for each nozzle based on this pre-stored inclination information, compensating for positioning errors and preventing color shifts and banding.
Solution Approach 2:
The control unit adjusts the ejection timing parameter for each nozzle based on the inclination information. By changing the timing parameter according to the specific inclination of each head, the system compensates for the spaces between heads and ensures accurate ink placement without requiring physical repositioning of the heads.
3Ease of manufacture
If the head unit is attached to incline due to manufacturing errors, then ink is applied at shifted positions causing color mixture failure and banding
Solution Approach 1:
Inclination information representing the actual inclination state of each head is stored in the inclination information storage unit. The control unit uses this feedback information to calculate and adjust the ejection timing for each nozzle, compensating for the inclination-induced positioning errors and maintaining accurate ink placement despite manufacturing tolerances.
Data Source
AI summary
There is provided a liquid ejecting apparatus including a head unit in which a plurality of heads in each of which a plurality of nozzles are disposed in a direction perpendicular to a recording medium transport direction are provided in the direction perpendicular to the recording medium transport direction, a control unit for driving the head unit based on image information and for performing a liquid ejection timing control for ejecting liquid from the nozzle to a recording medium for every nozzle, and an inclination amount storage unit in which inclination information of the head unit is preliminarily stored. The control unit has a calculator for calculating the most appropriate ejection timing with respect to the recording medium transport direction for every nozzle of each head from the image information and the inclination information of the head unit.