Printing Apparatus Time-Divisional Driving Order Control
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Solution Overview
Problem
Conventional printing apparatuses using time-divisional driving methods face issues with image uniformity due to density changes caused by the relationship between driving blocks and printing medium conveyance, leading to non-uniform dot layouts and impaired printing stability as the number of orifices increases.
Innovation Solution
A printing apparatus with a printhead that divides printing elements into groups, uses a scanning unit to reciprocally scan perpendicular to the orifice array, and employs a conveyance unit to adjust the printing medium conveyance in integer multiples of group width, while setting a driving order based on conveyance amounts to maintain consistent dot layouts across scans.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of orifices arrayed on a printhead is increased to achieve higher printing operation speeds and resolutions, then printing speed and resolution are improved, but discharge stability deteriorates due to pressure interference between neighboring orifices
Solution Approach 1:
The printhead is divided into multiple driving blocks, each independently controlling a subset of orifices. This segmentation isolates the pressure fields of different orifice groups, eliminating pressure interference between neighboring orifices while maintaining high printing speeds and resolutions through coordinated sequential operation of the blocks.
2Productivity
If all printing elements are simultaneously driven to increase productivity, then printing speed is improved, but voltage drop increases due to power loss on common power lines
Solution Approach 1:
The printing elements are divided into multiple driving blocks that operate sequentially rather than simultaneously. Each block draws power during its specific time slot, reducing the peak current demand on common power lines and minimizing voltage drop and power loss, while still achieving high printing speeds through rapid sequential operation.
Solution Approach 2:
The driving blocks operate in periodic time-divisional sequences, with each block activated for a specific duration followed by deactivation before the next block operates. This periodic operation pattern reduces instantaneous power consumption and allows the power supply system to operate more efficiently, reducing voltage drop and energy loss.
3Loss of energy
If time-divisional driving is used to reduce power loss, then energy efficiency is improved, but printing position shifts between driving blocks due to printhead movement during scanning
Solution Approach 1:
The system dynamically adjusts the timing and sequencing of driving block activation based on the real-time position of the printhead during scanning. By synchronizing the drive signals with the printhead's motion state and adjusting the conveyance amount dynamically, the system compensates for position shifts and maintains accurate printing registration across all driving blocks.
Solution Approach 2:
The system incorporates feedback mechanisms that monitor the actual position of the printhead and the conveyance of the printing medium during time-divisional driving. This feedback information is used to adjust the timing and positioning of subsequent driving block operations, compensating for any position drift and maintaining precise printing alignment.
4Adaptability or versatility
If the conveyance amount is not synchronized with the driving block pattern, then flexibility in conveyance control is improved, but density non-uniformity occurs due to inconsistent dot layout positions
Solution Approach 1:
The system changes the conveyance amount parameter in integer multiples of the driving block width to ensure that the printing medium position aligns with the driving block pattern at the end of each scanning cycle. This parameter adjustment maintains consistent dot layout positions across multiple passes while preserving flexibility in conveyance control for different printing scenarios.
Data Source
AI summary
A printing apparatus comprising, a printhead including an element array in which a plurality of printing elements are arrayed, scanning unit configured to reciprocally scan the printhead, driving unit configured to time-divisionally drive the printing elements, conveyance unit configured to convey a printing medium, and setting unit configured to set a driving order, wherein the conveyance unit performs a first conveyance operation of conveying the printing medium by a conveyance amount which is an integer multiple of a width of the group of the time-divisional driving, and a second conveyance operation of conveying the printing medium by a conveyance amount which is not an integer multiple of the width of the group, and the setting unit sets the driving order in the time-divisional driving for each scan based on the conveyance amount by the conveyance unit.