Line Head Mask Control for Variable-Width Inkjet Printing
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Solution Overview
Problem
Existing ink-jet recording apparatuses face challenges in forming multicolor images on sheets of varying widths without ink droplets protruding beyond the sheet edges, leading to potential contamination of the conveying mechanism.
Innovation Solution
The apparatus incorporates a sheet width sensor and a controller that detects the sheet width and adjusts ink ejection by executing mask processing to reduce the image size when the sheet width is smaller than the intended width, ensuring ink droplets are confined within the sheet boundaries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If mask processing is applied to all line heads simultaneously, then ink droplets are prevented from protruding beyond sheet edges, but image width is reduced when sheets are conveyed with misalignment
Solution Approach 1:
The patent applies dynamic control by setting different mask processing start positions for different line heads based on their individual misalignment amounts. The controller dynamically adjusts the mask processing parameters for each line head according to real-time sheet width detection, rather than applying a uniform mask to all line heads. This resolves the contradiction by allowing each line head to have optimized mask processing that prevents ink protrusion while maintaining correct image width.
Solution Approach 2:
The patent implements local quality control by applying mask processing with different start positions to different line heads based on their specific misalignment characteristics. Each line head receives tailored mask processing parameters proportional to its misalignment amount, rather than a blanket approach. This localized adjustment prevents ink droplet protrusion at each line head's specific location while preserving the overall image width integrity.
2Object-affected harmful factors
If sheet width detection is implemented, then ink ejection can be adjusted to match sheet boundaries, but device complexity increases
Solution Approach 1:
The patent achieves universality by making the sheet width detection mechanism serve multiple functions: it detects sheet width for mask processing control, identifies sheet position for alignment correction, and provides feedback for dynamic parameter adjustment across all line heads. This multi-functional use of the detection system prevents ink contamination while minimizing the added device complexity, as one detection mechanism fulfills multiple control requirements.
Solution Approach 2:
The patent replaces complex mechanical adjustment mechanisms with electronic control based on optical sheet width detection. Instead of mechanically adjusting each line head's position or mask parameters, the system uses optical detection of sheet width and electronically calculates and applies appropriate mask processing parameters. This substitution reduces mechanical complexity while effectively preventing ink contamination through software-based adaptive control.
Data Source
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AI summary
A controller (38) of an ink-jet recording apparatus (10) creates, for each of line heads (15Y, 15B, 15C, 15M), a print queue of print jobs each for forming a multicolor image on a sheet (P) and executes the print jobs according to the print queue. When a width of the sheet (P) is smaller than a sheet width for use in the print job not yet being executed, the controller (38) sets, on a basis of each of the line heads (15Y, 15B, 15C, 15M), width information on the sheet (P) in association with the print job not yet being executed at the line head and executes, based on the width information set to the print job not yet being executed at each of the line heads, mask processing for narrowing a color image of the print job not yet being executed in a widthwise direction of the sheet (P).