Thermal Printhead Control via Frame Dot State Sequences

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Solution Overview

Problem

Thermal printing devices face inefficiencies in power usage and precision, particularly in high-speed commercial and industrial applications, leading to issues like blurred images, stray dots, and overheating, which affect the quality of printed barcodes and labels.

Innovation Solution

The method involves dividing print data lines into frames, analyzing neighbor memory layouts to determine frame dot state sequences, and adjusting motor speeds based on line strobe times, allowing for precise control of printhead dots and media movement, thereby optimizing energy distribution and reducing overheating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high-speed printing is implemented, then productivity increases, but manufacturing precision deteriorates due to blurred images and stray dots

Engineering Contradiction:
Improveprinting speedVSAvoidimage quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent segments the printing process into discrete line-based operations with individual strobe time control. Each line of print data is processed independently with optimized dot activation sequences, allowing high-speed operation while maintaining precision through controlled energy delivery to each dot image position.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements preliminary analysis of neighbor memory layouts to determine optimal frame dot state sequences before actual printing. This pre-computation of dot activation patterns enables the printhead to execute precise printing operations at high speeds without real-time calculation delays.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If high energy is applied to printhead dots, then manufacturing precision improves, but object-generated harmful factors worsen due to overheating

Engineering Contradiction:
Improvedot image precisionVSAvoidoverheating
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent employs periodic strobe timing patterns where printhead dots are activated in controlled sequences rather than continuously. The frame dot state sequences create periodic on/off cycles that deliver precise energy doses for dot image formation while allowing thermal dissipation between activation cycles, preventing overheating.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent dynamically adjusts strobe time parameters based on the specific dot state requirements. By varying the duration and timing of dot activations according to the neighbor memory layout analysis, the system optimizes energy delivery to achieve precise dot images while controlling thermal accumulation through parameter modulation.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If continuous monitoring and adjustment of printing parameters is implemented, then manufacturing precision improves, but device complexity increases

Engineering Contradiction:
Improveprint quality controlVSAvoidcontrol system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent performs preliminary determination of frame dot state sequences by analyzing neighbor memory layouts before printing execution. This pre-computation approach consolidates the complex control logic into offline calculations, simplifying the real-time printing control while maintaining high precision through pre-optimized dot activation patterns.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses the neighbor memory layout as a template or copy of the desired print pattern to determine subsequent frame dot states. By referencing and copying successful dot state sequences from neighboring lines, the system achieves consistent high-quality printing without requiring complex real-time control algorithms for each line.

Inventive Principle:
Principle #26Copying

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

This approach enhances the precision and quality of printed images by efficiently managing printhead energy and motor speeds, reducing unnecessary heating and conserving power, while maintaining high-speed printing capabilities.

Implementation Method 1

Applying energy to the dots of the thermal printhead heats the dots and permits the heat energy generated by the dots to be transferred to the media to image (i.e., print) the media

Methodology Applied
Scientific EffectThermal heating: Heating

Implementation Method 2

the media may be synthetic, rather than being paper-based. A synthetic media may be configured to change from clear to black in response to absorbing a threshold amount of heat energy

Methodology Applied
Scientific EffectThermal absorption: Absorption (EM radiation)

Data Source

PatentEP3581390B1Method and apparatus for printhead control
Publication Date: 2021.07.07 ZEBRA TECHNOLOGIES CORP
  • EP3581390B1 patent drawingFigure 1A
  • EP3581390B1 patent drawingFigure 1B~1D
  • EP3581390B1 patent drawingFigure 2A~2D

AI summary

A method, apparatus, and computer program product are described herein for controlling a printing device. In an example embodiment, a print line is divided into frames and frame dot states are determined based on neighboring frame dot states. Maximum motor speeds of the printing device may be adjusted so that actual motor speeds change gradually during printing. The print engine may detect a printhead type by sending a signal to the printhead and receiving a response.