Cooling Roller Prevents Condensation in High-Speed Inkjet Printing

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Solution Overview

Problem

Ink jet printing apparatuses face issues with condensation on the print head due to temperature differences between the paper and the print head, leading to printing troubles when continuous paper is printed twice with a time difference on both its front and back faces at high speeds.

Innovation Solution

A printing apparatus with multiple trains of print heads and a dryer section, combined with a cooling roller system that winds and cools the paper, and a turnover mechanism to manage paper orientation and direction, preventing condensation on the print head by maintaining a stable temperature and reducing moisture vapor generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If continuous paper is printed twice with a time difference on both front and back sides at high speed, then printing productivity is improved, but condensation occurs on the ink discharge nozzle surface causing printing troubles

Engineering Contradiction:

Improveprinting speedVSAvoidprinting stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by providing a cooling roller that cools the continuous paper immediately after it passes through the dryer section, before the paper enters the print head. This preliminary cooling prevents the paper temperature from rising too high during high-speed printing, thereby preventing condensation on the ink discharge nozzle surface and maintaining printing stability without reducing printing speed.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If the paper is heated in the dryer section for drying the print, then drying efficiency is improved, but the paper temperature becomes higher than the ink discharge surface temperature causing condensation

Engineering Contradiction:

Improvedrying efficiencyVSAvoidpaper temperature

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The patent introduces a cooling roller as an intermediary element between the dryer section and the print head. This cooling roller acts as a temperature mediator that receives the hot paper from the dryer and cools it down to a suitable temperature before it reaches the print head, thus preventing condensation while maintaining efficient drying.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If a moisture condensing or absorbing member is provided in the vicinity of the print head, then condensation prevention is improved, but the device complexity increases

Engineering Contradiction:

Improvecondensation preventionVSAvoidapparatus structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the condensation prevention function from the print head area and relocates it to the paper path between the dryer and print head. By placing the cooling roller in this specific location, the system prevents condensation at its source (on the paper surface) rather than trying to manage it at the print head, simplifying the overall apparatus structure.

Inventive Principle:

Principle #2Taking out (Extraction)

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 setup allows for high-speed printing on continuous paper without causing condensation-related printing troubles, ensuring efficient drying and cooling of the paper, thus preventing issues at the ink discharge nozzle surface.

Implementation Method 1

a cooling roller means disposed downstream of the dryer section and having a cooling roller on which the plurality of continuous sheets of paper from the dryer section can be wound

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a dryer section in which a plurality of continuous sheets of paper from the plural printing unit trains can travel as mutually shifted in position

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 3

it is dried as it is passed through a dryer section at each time of printing

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS7810921B2Printing apparatus

Publication Date: 2010.10.12 MIYAKOSHI PRINTING MACHINERY

AI summary

To allow continuous paper to be printed a plurality of times with a time difference by ink jet printer equipment and dried each time of printing while preventing condensation from occurring on an ink discharge surface of print head at and after the second time of printing, there is provided a printing apparatus comprising: a plurality of trains of printing units each of which has print heads arranged along a direction in which a continuous sheet of paper travels and which are arranged parallel to one another as shifted mutually in position in a direction of width of the continuous sheet of paper; a dryer section in which a plurality of continuous sheets of paper from the plural printing unit trains can travel as mutually shifted in position in a direction of width of the continuous sheet of paper; a cooling roller unit disposed downstream of the dryer section and having a cooling roller on which the plurality of continuous sheets of paper from the dryer section can be wound as mutually shifted in position in a direction of width of the continuous sheet of paper; and a turnover unit disposed between the cooling roller unit and a train of printing units for shifting the continuous sheet of paper in position into a direction of its width while reversing the direction in which it travels.