Pinch Roller Sets for Print Sheet Conveying

Solution Overview

Problem

Existing printing apparatuses face challenges in maintaining print sheet conveying performance while keeping costs low and size small, especially when modifying to accommodate different sheet widths, as they often require additional pinch rollers, increasing costs and size, and struggle to press lateral edges of wide sheets effectively, leading to issues like ink smudges and jams.

Innovation Solution

The printing apparatus employs a configuration with adjustable pinch roller sets, where two pinch rollers are positioned at the center and three at the ends, with offset axles and springs to maintain uniform pressure, allowing for efficient conveying of various sheet sizes without unnecessary size or cost increases, using highly slidable plastic or elastomer-covered pinch rollers to ensure even pressure distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pinch rollers are increased to accommodate wider print sheets, then conveying performance is improved, but apparatus size and cost increase

Engineering Contradiction:

Improveconveying performanceVSAvoidapparatus size

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent applies local quality by using pinch rollers of different sizes at different positions. Specifically, it employs one large pinch roller at the center for wide sheets and two small pinch rollers at the ends for edge control. This localized differentiation allows the system to handle various sheet widths effectively without uniformly increasing all pinch rollers, thereby avoiding unnecessary apparatus size expansion.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements multi-functionality through a mixed configuration where pinch rollers serve multiple purposes. The large central pinch roller handles both wide sheet conveying and edge control, while the small end pinch rollers specifically control lateral edges. This universal design allows a single apparatus to accommodate multiple print sheet widths (A3, A4, Legal, Tabloid) without requiring separate dedicated rollers for each function.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If pinch rollers are increased to accommodate wider print sheets, then conveying performance is improved, but cost increases

Engineering Contradiction:

Improveconveying performanceVSAvoidcost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies local quality by using pinch rollers of different sizes at different positions. Specifically, it employs one large pinch roller at the center for wide sheets and two small pinch rollers at the ends for edge control. This localized differentiation allows the system to handle various sheet widths effectively without uniformly increasing all pinch rollers, thereby avoiding unnecessary apparatus size expansion.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements multi-functionality through a mixed configuration where pinch rollers serve multiple purposes. The large central pinch roller handles both wide sheet conveying and edge control, while the small end pinch rollers specifically control lateral edges. This universal design allows a single apparatus to accommodate multiple print sheet widths (A3, A4, Legal, Tabloid) without requiring separate dedicated rollers for each function.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of manufacture

If pinch rollers are made uniform in size, then manufacturing is simplified, but ability to press lateral edges of various sheet sizes is compromised

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidedge pressing capability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies local quality by using pinch rollers of different sizes at different positions. Specifically, it employs one large pinch roller at the center for wide sheets and two small pinch rollers at the ends for edge control. This localized differentiation allows the system to handle various sheet widths effectively without uniformly increasing all pinch rollers, thereby avoiding unnecessary apparatus size expansion.

Inventive Principle:

Principle #3Local quality

4Volume of stationary object

If lateral edges of wide print sheets are not pressed, then apparatus size is kept small, but ink smudges and jams occur

Engineering Contradiction:

Improveapparatus sizeVSAvoidink smudges and jams

Core Design Contradiction:

Volume of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by using pinch rollers of different sizes at different positions. Specifically, it employs one large pinch roller at the center for wide sheets and two small pinch rollers at the ends for edge control. This localized differentiation allows the system to handle various sheet widths effectively without uniformly increasing all pinch rollers, thereby avoiding unnecessary apparatus size expansion.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent extracts the edge control function from the main conveying function by separating the pinch roller roles. The large central pinch roller focuses on conveying wide sheets, while the two small end pinch rollers are specifically extracted to handle lateral edge control. This functional separation allows edge control to be achieved without requiring all pinch rollers to be large, thus preventing apparatus size increase while preventing ink smudges and jams.

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 configuration maintains print sheet conveying performance across different sizes while minimizing apparatus size and cost, preventing edge curling and jams, and ensuring consistent pressure distribution despite potential deformations in the support mechanism.

Implementation Method 1

springs to maintain uniform pressure

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

highly slidable plastic or elastomer-covered pinch rollers to ensure even pressure distribution

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS8845217B2Printing apparatus

Publication Date: 2014.09.30 CANON KK

AI summary

A printing apparatus capable of maintaining print sheet conveying performance while keeping apparatus cost low and apparatus size small is provided. The printing apparatus includes a conveying mechanism and a print unit. The conveying mechanism includes a conveying roller which is a driving roller, a plurality of pinch rollers which are passive rollers disposed facing the conveying roller, and a plurality of pinch roller axles supporting the pinch rollers. The print unit prints onto a sheet conveyed by the conveying rollers and the plurality of pinch rollers. The conveying mechanism includes one or more first pinch roller sets including two pinch rollers and a first pinch roller axle supporting the two pinch rollers, and one or more second pinch roller sets including three pinch rollers and a second pinch roller axle supporting the three pinch rollers.