Printing Apparatus with Rotating Drum and Segmented Printheads

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Solution Overview

Problem

Current digital drum printing technologies face limitations in printing speed and efficiency, particularly when dealing with media of varying lengths, as they require multiple printheads and result in increased processing time due to the need for linear motion and part loading delays.

Innovation Solution

The proposed solution involves dividing the printing medium into multiple areas and using multiple printheads with equal pitch and length, allowing for synchronized motion and alternating usage to balance printhead utilization, thereby reducing overall printing time and increasing speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple printheads are arranged in a straight line to print different colors, then complete color printing can be achieved, but the printing medium must pass through all printheads along the straight line, increasing the distance and reducing printing speed

Engineering Contradiction:
Improvecolor printing capabilityVSAvoidprinting speed
Core Design Contradiction:
Adaptability or versatilityVSSpeed

Solution Approach 1:

The patent transitions from a one-dimensional linear arrangement of printheads to a two-dimensional circular arrangement around the drum. Multiple printheads are positioned at different angular positions around the drum's circumference, allowing simultaneous printing of different colors on the same section of printing medium as it passes by, thereby eliminating the need for the medium to travel through all printheads sequentially.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Speed

If the printhead and drum move continuously and synchronously at an included angle, then printing speed on a single drum is improved, but the method cannot meet printing requirements for longer printing media

Engineering Contradiction:
Improveprinting speedVSAvoidprinting medium length adaptability
Core Design Contradiction:
SpeedVSAdaptability or versatility

Solution Approach 1:

The patent divides the printing task into multiple segments by positioning different printheads at different angular positions around the drum. Each printhead is responsible for printing a specific color or section, and they operate simultaneously and independently. This segmentation allows the system to handle printing medium of various lengths effectively, as each printhead works on its designated portion without requiring the entire medium to be processed sequentially.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If multiple printheads are used to print different colors, then complete color printing is achieved, but printing time increases due to sequential processing

Engineering Contradiction:
Improvecolor printing capabilityVSAvoidprinting time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent enables continuous simultaneous printing by arranging multiple printheads around the drum so that they all operate at the same time on different color channels. As the printing medium passes through the printing zone, all printheads deposit their respective colors concurrently, eliminating the sequential waiting time that would occur if printheads operated one after another. This continuous parallel action significantly reduces total printing time while maintaining full color capability.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP3909780B1Printing apparatus and method
Publication Date: 2024.10.02 SUZHOU RUIFA PRINTING TECH CO LTD
  • EP3909780B1 patent drawingFigure 1a~2a
  • EP3909780B1 patent drawingFigure 2b~3a
  • EP3909780B1 patent drawingFigure 3b~4a

AI summary

The present application proposes a printing apparatus, including n printheads (1, 2, 3) arranged along the first direction (11), each printhead communicating with at least two different inks; a printing medium (30) opposing to the printheads, the printing medium configured to rotate around a rotational axis (G) ; a motion controller (52) that controls the motions of the printheads and the printing medium; a printing driver (51) that controls the printing of the printheads; the printing medium being divided into s printing areas (H, J, K) along the first direction, such that each printing area is configured to be printed by a printhead, where s and n are positive integers greater than 1. The printing apparatus and printing method proposed in this invention reduce the relative moving distance between the printheads and the printing medium during the printing process by dividing the printing area into multiple printing areas, thereby reducing the overall printing time and increasing the printing speed.