Air-Permeable Belt Transport with Protrusion-Recess Positioning

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Solution Overview

Problem

Existing sheet transport apparatuses for inkjet printers are expensive due to the use of costly materials and complex control systems, and they often result in wrinkles that can deform sheets and damage print heads.

Innovation Solution

A low-cost sheet transport apparatus using an air-permeable belt with an endless protrusion and corresponding recesses on rollers, where the protrusion only exerts lateral forces to control the belt's position, allowing the use of cheaper plastic materials and preventing wrinkles by ensuring the belt remains flat and tensioned.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sensors and actuators are used to control belt position, then positioning accuracy is improved, but device cost increases

Engineering Contradiction:
Improvebelt position control accuracyVSAvoidcontrol system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the belt positioning function from complex sensor-actuator systems and implements it through a simple mechanical protrusion-recess mechanism. The protrusion on the belt engages with a recess in the roller, providing inherent lateral positioning without requiring external sensors or actuators. This eliminates the need for expensive positioning systems while maintaining accurate belt alignment.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The belt positioning system is self-regulating through the geometric constraint of the protrusion fitting within the recess. The belt automatically maintains its lateral position through the mechanical interference between the protrusion and recess, without requiring external control systems. The system serves itself by using the belt's own structure to achieve positioning.

Inventive Principle:
Principle #25Self-service

2Strength

If metal belts are used for transport, then belt strength is improved, but manufacturing cost increases

Engineering Contradiction:
Improvebelt strengthVSAvoidmanufacturing cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent changes the material parameter from metal to plastic for the belt, reducing manufacturing cost while maintaining sufficient strength through proper plastic material selection and belt tensioning. The protrusion-recess mechanism provides the necessary structural support and positioning, allowing cost-effective plastic materials to be used instead of expensive metal alternatives.

Inventive Principle:
Principle #35Parameter changes

3Speed

If the protrusion transfers driving forces to the belt, then belt movement control is improved, but belt wrinkles increase

Engineering Contradiction:
Improvebelt movement controlVSAvoidbelt flatness
Core Design Contradiction:
SpeedVSShape

Solution Approach 1:

The recess in the roller is designed with specific local geometry that allows the protrusion to engage laterally for positioning while preventing longitudinal force transfer. The recess extends in the lateral direction but has limited depth, creating a mechanical constraint that restricts protrusion movement in the transport direction while allowing lateral positioning. This local geometric design eliminates belt wrinkles by preventing excessive force concentration at the protrusion-belt interface.

Inventive Principle:
Principle #3Local quality

4Measurement precision

If the recess depth is increased to better restrict protrusion movement, then lateral positioning is improved, but driving force transfer is enhanced

Engineering Contradiction:
Improvelateral position controlVSAvoiddriving force transfer
Core Design Contradiction:
Measurement precisionVSForce

Solution Approach 1:

The recess is designed with asymmetric dimensions where the lateral width is sufficient to engage the protrusion for positioning, but the depth is limited to prevent significant force transfer in the transport direction. The recess geometry is optimized to provide lateral constraint while maintaining minimal longitudinal engagement, creating an asymmetric force distribution that prioritizes positioning over driving force transfer.

Inventive Principle:
Principle #4Asymmetry

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

The solution provides accurate lateral control of the belt without increasing costs, using plastic belts that are cheaper to produce and maintain flatness, reducing material usage and weight, while preventing wrinkles and potential damage to the print head.

Implementation Method 1

Sheets are adhered to the air-permeable belt via suction

Methodology Applied
Scientific EffectSuction: Suction

Implementation Method 2

driving forces from the driving roller are transferred to the belt via direct contact between the belt and the circumferential surface of the driving roller

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3636568B1Sheet transport apparatus for an inkjet sheet printer
Publication Date: 2024.04.03 CANON PRODN PRINTING HLDG BV
  • EP3636568B1 patent drawingFigure 1~2
  • EP3636568B1 patent drawingFigure 3~4
  • EP3636568B1 patent drawingFigure 5~6

AI summary

The present invention provides a low costs sheet transport apparatus comprising an endless air permeable belt (101). An endless protrusion (102) is secured onto the belt and extending a predetermined height out of the surface of the belt. A plurality of rollers (110-113) comprising a driving roller (110) driveable by means of an actuator (122) and at least one support roller (111-113) positioned with respect to the driving roller to tension the belt over the plurality of rollers, such that a rotation of the driving roller moves the belt in a transport direction (D) is provided. At least one of the plurality of rollers comprises an endless recess (115) dimensioned to receive the protrusion, such that the protrusion is substantially prevented from transferring driving forces in the transport direction from the plurality of rollers to the belt. The protrusion is suspended within the recess such that it is prevented from transferring forces in the transport direction to belt.