Ink Jet Printer Timing Compensation for Envelope Print Distortion
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Solution Overview
Problem
High-speed mail processing systems face image distortion issues when printing on envelopes with irregular surfaces, leading to reduced machine and human readability due to varying envelope velocities and inserted items causing irregularities, which complicates meeting postal regulations.
Innovation Solution
Adjusting the timing of ink drops from an ink jet printer to compensate for non-flat surfaces by applying appropriate delays, ensuring ink drops arrive simultaneously on the mail piece surface, using empirical observations of mail piece characteristics to determine delay characteristics, applicable to both thermal ink jets and other drop-on-demand technologies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If envelopes are processed at high velocity (100-120 ips) to meet mail processing requirements, then productivity increases, but image distortion increases due to varying displacements between print nozzle plane and points within the print image space
Solution Approach 1:
The system pre-calculates and stores delay values for each print location based on the envelope thickness map before printing begins. This preliminary preparation allows the print controller to apply the correct delays without real-time computation, enabling high-speed printing while maintaining image accuracy through pre-determined compensation values.
Solution Approach 2:
The system changes the timing parameter of ink drop ejection by applying location-specific delays. The print controller modifies the ejection timing of ink drops based on the measured envelope thickness at each print location, compensating for the varying distances from the print nozzle to different points on the envelope surface, thus correcting image distortion at high velocities.
2Device complexity
If ink drops are applied without delay compensation on non-flat surfaces, then device complexity is reduced, but manufacturing precision deteriorates due to image distortion from varying ink drop travel distances
Solution Approach 1:
The envelope thickness map is measured and stored in memory before printing, and delay values are pre-calculated for each print location. This preliminary preparation simplifies the printing process by eliminating the need for complex real-time calculations or additional hardware, while still achieving precise image placement through pre-determined timing compensation.
Solution Approach 2:
The system replaces complex mechanical adjustment mechanisms with a digital timing control system. Instead of physically adjusting the print nozzle position or envelope positioning, the system uses software-based delay application to ink drop ejection timing, substituting mechanical complexity with electronic control while maintaining manufacturing precision.
3Adaptability or versatility
If envelopes with thick inserts are printed after stuffing, then adaptability to different mail compositions is improved, but image distortion increases due to irregularities on the envelope surface from stepped mail
Solution Approach 1:
The system applies different delay values to different locations on the envelope based on the local thickness measured at each print position. The envelope thickness map captures local variations caused by inserts, and the print controller applies location-specific delays to compensate for these variations, ensuring accurate image placement across the entire envelope surface regardless of insert configuration.
Solution Approach 2:
The system automatically measures the envelope thickness, generates the thickness map, calculates delay values, and applies the appropriate delays during printing without requiring manual intervention or reconfiguration. This self-service capability allows the system to adapt to different mail compositions (envelopes with or without inserts) while maintaining print accuracy through automated compensation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Improves machine and human readability of printed images, enabling higher processing speeds by reducing image distortion and maintaining readability at increased velocities, thus increasing the efficiency of mail production.
Implementation Method 1
a print controller delays ejection of ink drops from an ink jet printer
Implementation Method 2
digital printing, such as thermal inkjet technology
Data Source
AI summary
A method and system are disclosed for ejecting ink drops from a plurality of ink jet nozzles in order to print on an envelope in a mail piece production process. The envelope has been stuffed and is therefore not flat, especially near the edges. Mail piece composition data is obtained and stored for the mail piece, and based upon that composition data a nozzle delay pattern is determined. For each ink jet nozzle, ink is ejected in accordance with the delay pattern so as to contact a point of the envelope's surface at the same time as drops from other ink jet nozzles.