Inkjet Recording Head Nozzle Control for End Portion Streaks
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Solution Overview
Problem
Inkjet recording apparatuses face challenges in maintaining image quality due to reduced conveying accuracy at the end portions of the recording medium, leading to issues like black and white streaks and textured images, caused by variations in the head-paper distance and inadequate holding of the recording medium by rollers.
Innovation Solution
A recording apparatus and method that dynamically adjust the number of nozzles used for recording on the front or rear end portions based on selected recording modes, balancing image quality and recording time by altering the nozzle usage rate during scanning and subscanning operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the recording medium is conveyed by discharge rollers at the rear end portion, then the recording medium can be discharged reliably, but the conveying accuracy is reduced causing black or white streaks
Solution Approach 1:
The patent applies dynamics by making the nozzle operation dynamic and adaptive based on recording position. The control unit dynamically adjusts nozzle operation to skip or reduce ink discharge at rear end portions where conveying accuracy deteriorates, while maintaining normal operation in central portions. This dynamic adaptation resolves the contradiction by allowing reliable discharge through the rollers while compensating for their inferior conveying accuracy through selective nozzle deactivation.
Solution Approach 2:
The patent applies local quality by differentiating nozzle operation based on spatial location on the recording medium. Different regions (central portion vs. rear end portion) receive different treatment: central portions use full nozzle operation for high quality, while rear end portions use reduced or skipped nozzle operation to avoid streaks caused by roller conveying inaccuracies. This local differentiation resolves the contradiction by optimizing quality and reliability for each specific region.
2Adaptability or versatility
If the head-paper distance varies during recording, then the recording can cover the entire recording medium including end portions, but the image quality deteriorates due to unstable positioning
Solution Approach 1:
The patent applies parameter changes by modifying the operational parameters of the nozzles based on recording position. The control unit changes the discharge parameter (ink discharge amount or frequency) according to the head-paper distance variation that occurs at different recording positions. At rear end portions where head-paper distance varies significantly, the system reduces or skips nozzle operation to prevent positioning errors from causing quality deterioration, while maintaining full operation in central portions with stable positioning.
3Productivity
If all nozzles are used for recording at end portions, then the recording speed is maintained, but the image quality deteriorates due to conveying errors
Solution Approach 1:
The patent applies partial action by using only a subset of nozzles for recording at rear end portions instead of all nozzles. The control unit selectively activates or deactivates specific nozzles based on their discharge positions, skipping nozzles that would cause streaks due to conveying errors while using others to maintain recording progress. This partial nozzle operation maintains acceptable recording speed while preventing quality deterioration from excessive ink discharge in problematic areas.
Data Source
AI summary
A recording apparatus is configured to record an image on a recording medium by repeating a recording operation and a conveying operation. The recording operation is operative to apply a recording agent to the recording medium using a recording head while moving the recording head for scanning in a direction different from a predetermined direction. The recording head includes a plurality of recording elements arranged in the predetermined direction and adapted to apply the recording agent. The conveying operation is operative to convey the recording medium in a direction transverse to the scanning direction. The recording apparatus includes a recording control unit configured to perform the recording operation such that a number of the recording elements which are used to record an image on at least one of a front end portion and a rear end portion of the recording medium is reduced at a rate as compared to that of the recording elements which are used to record an image on a central portion of the recording medium, and a recording mode selecting unit configured to select a recording mode from a plurality of recording modes differing from one another in at least one of recording quality and recording time. The recording control unit changes the rate of reduction according to the recording mode selected by the recording mode selecting unit.