Printer Sheet Conveyer Position Detection for Jam Prevention

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Solution Overview

Problem

In image forming apparatuses, when the movable unit is removed from the guide position, the conveyance of sheets is stopped, increasing the user's load for maintenance operations, as they need to manually remove sheets from the main body guide, which can be cumbersome, especially for longer sheets.

Innovation Solution

The apparatus includes a position detector and controller that determine the movable unit's position and control the conveyer to feed the sheet by a specific amount if it's not in the guide position, allowing easy removal by guiding it to the guide position, reducing maintenance load. The controller also adjusts the feeding amount based on sheet length and stops feeding if the unit is in the guide position to prevent jamming.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the movable unit is removed from the guide position, then the user can access the main body guide for maintenance, but the sheet conveyance is stopped and the user must manually remove sheets increasing maintenance load

Engineering Contradiction:
Improveease of maintenance accessVSAvoidmaintenance time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The system performs preliminary detection of the movable unit's position status before maintenance operation begins. When the movable unit is detected to be in the guide position, the system automatically executes a feeding operation to advance the sheet by a predetermined amount, preparing the sheet for easy removal during maintenance without requiring manual intervention.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system enables self-service maintenance by automatically detecting when the movable unit is in the guide position and autonomously performing the sheet feeding operation. This eliminates the need for users to manually manipulate sheets during maintenance, allowing the system to serve itself in preparing for maintenance access.

Inventive Principle:
Principle #25Self-service

2Reliability

If the movable unit is not in the guide position, then the sheet may not be guided properly and conveyance stops, but manual sheet removal becomes necessary increasing maintenance complexity

Engineering Contradiction:
Improvesheet guidance reliabilityVSAvoidmaintenance operation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system employs feedback through position detection means that continuously monitor whether the movable unit is in the guide position. Based on this feedback, the control means automatically determines whether to execute the feeding operation, ensuring reliable sheet guidance while simplifying maintenance operations through automated decision-making.

Inventive Principle:
Principle #23Feedback

3Ease of operation

If the feeding operation is not performed when the movable unit is not in the guide position, then sheet guidance may be compromised, but user load during maintenance increases

Engineering Contradiction:
Improveease of sheet removalVSAvoidsheet positioning precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The system performs preliminary feeding of the sheet by a predetermined amount when detecting that the movable unit is in the guide position, preparing the sheet for optimal removal position before maintenance begins. This preliminary action ensures both ease of sheet removal and maintains positioning precision through controlled automated movement.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2728419B1Image forming apparatus including sheet conveyer conveying a sheet and guide guiding the sheet
Publication Date: 2019.01.16 BROTHER KOGYO KK
  • EP2728419B1 patent drawingFigure 1
  • EP2728419B1 patent drawingFigure 2
  • EP2728419B1 patent drawingFigure 3

AI summary

In a printer (1), if it is determined that a sheet tray (31) is not in a guide position Z (NO at S11), a sheet M that is on a main body side re-convey guide (63) is fed toward the guide position Z (S15, S16). Accordingly, the sheet tray (31) is moved from the guide position Z with respect to a main body (2), the sheet M is easily removed from the re-convey guide (63) compared to a configuration without performing feeding of the sheet. This reduces a user's load of a maintenance operation.