Line Inkjet Printer Discharge Amount Adjuster for Color Uniformity

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In line inkjet printers, displacement of ink droplets between head modules of different colors leads to color differences in printed images due to misalignment or varying discharge characteristics, which existing solutions like multipass inkjet printers or Japanese Patent Laid-Open No. 2006-168241A are impractical or ineffective for multicolor printing.

Innovation Solution

An ink discharge amount adjuster system for line inkjet printers that includes displacement information setting, correction content determination, and discharge amount correction for each nozzle to ensure ink droplets from multiple head modules land accurately on the same pixel, using a control unit to adjust the discharge amount based on acquired concentration and displacement information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a multipass inkjet printer is used to solve landing position displacement, then the landing position accuracy is improved, but the printing productivity deteriorates due to reciprocating motion and the enormous processing required for line inkjet printers with large numbers of nozzles

Engineering Contradiction:

Improvelanding position accuracyVSAvoidprinting productivity

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The invention measures and stores the actual landing positions of ink droplets from each nozzle in advance, then uses this pre-acquired information to calculate and apply correction values that compensate for discharge direction characteristics. This preliminary action eliminates the need for reciprocating motion during printing, thereby maintaining high productivity while achieving accurate landing positions.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention changes the discharge amount parameter of ink droplets based on pre-measured landing position data. By adjusting the discharge amount according to correction values derived from actual landing positions, the system compensates for discharge direction variations without requiring mechanical reciprocation, thus resolving the contradiction between precision and productivity.

Inventive Principle:

Principle #35Parameter changes

2Speed

If head modules are attached at intervals in the transfer direction to enable one-path printing, then the printing speed is improved, but the color accuracy deteriorates due to displacement in landing positions of ink droplets of different colors

Engineering Contradiction:

Improveprinting speedVSAvoidcolor accuracy

Core Design Contradiction:

SpeedVSManufacturing precision

Solution Approach 1:

The invention applies local quality correction by individually measuring and correcting the discharge characteristics of each nozzle in each head module. The correction values are specific to each nozzle's landing position, allowing the system to maintain high printing speed with one-path printing while achieving accurate color reproduction through localized compensation for each nozzle's discharge direction characteristics.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention implements a feedback mechanism where the actual landing positions of ink droplets are measured and used to calculate correction values that are then applied to the discharge amount control. This closed-loop feedback system ensures that despite the fixed head module positions required for high-speed one-path printing, the landing positions and color accuracy are maintained through continuous correction based on measured data.

Inventive Principle:

Principle #23Feedback

3Stability of the object's composition

If the discharge amount of ink droplets is increased to compensate for displacement, then the color uniformity is improved, but the ink consumption increases and may cause other printing quality issues

Engineering Contradiction:

Improvecolor uniformityVSAvoidink consumption

Core Design Contradiction:

Stability of the object's compositionVSLoss of substance

Solution Approach 1:

The invention precisely adjusts the discharge amount parameter of each nozzle based on its specific landing position characteristics. Rather than uniformly increasing discharge amounts, the system applies targeted corrections that compensate for displacement while minimizing excess ink usage. This precise parameter control achieves color uniformity without unnecessary ink consumption or associated printing quality problems.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8857941B2Ink discharge amount adjuster for each color of line inkjet printer

Publication Date: 2014.10.14 RISO KAGAKU CORP

AI summary

Displacement information indicating a displacement amount of landing position in a main scanning direction of ink droplets discharged respectively from the nozzle of the head module of the same array of the line head of each color is acquired for each head module of the same array (steps S5, S7). Based on the displacement information and concentration information for each array, a color degree of an image when the discharge amount of ink droplets discharged from a nozzle of a head module of each color is not adjusted is specified for each head module of each array (step S9). A correction voltage value of a drive signal for the discharge of the nozzle of the head module of each color, which is suitable to return the specified color degree to “0”, is calculated (step S11) and each corresponding nozzle is driven by the drive signal of the correction voltage value.