Photosensitive Drum Cartridge Positioning Shaft Design

Solution Overview

Problem

The existing configuration of image forming apparatuses, where the drum frame can deform due to heat, disrupts the relative positional relationship between the roller and the roller receiving portion, leading to degradation of positioning accuracy of the developing cartridge relative to the drum cartridge and subsequently to the main casing.

Innovation Solution

A photosensitive drum cartridge with a drum frame that includes a mounting portion for the developing cartridge and a positioning shaft with a first abutment portion, exposed through an opening, to ensure accurate positioning by maintaining the relative positional relationship despite potential deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the drum frame is made to accommodate the developing cartridge with a roller receiving portion, then the assembly can be manufactured and operated, but the positioning accuracy degrades when the drum frame deforms due to heat

Engineering Contradiction:

Improveassembly capabilityVSAvoidpositioning accuracy

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The positioning function is separated from the drum frame structure. A dedicated positioning shaft is introduced as an independent component that provides positioning reference, while the drum frame maintains its structural accommodation function. This segmentation allows the drum frame to deform thermally without affecting positioning accuracy, as the positioning shaft maintains its own dimensional stability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The positioning shaft acts as an intermediary element between the drum frame and the developing cartridge. It provides a stable positioning reference that mediates the relationship between these two components, ensuring accurate positioning even when the drum frame deforms due to thermal expansion or contraction.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If the roller and roller receiving portion are positioned to regulate developing frame movement, then the developing cartridge can be positioned relative to the drum cartridge, but heat-induced deformation of the drum frame disrupts this positional relationship

Engineering Contradiction:

Improveassembly operationVSAvoidpositional relationship accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The positioning function is separated from the drum frame structure. A dedicated positioning shaft is introduced as an independent component that provides positioning reference, while the drum frame maintains its structural accommodation function. This segmentation allows the drum frame to deform thermally without affecting positioning accuracy, as the positioning shaft maintains its own dimensional stability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The positioning mechanism uses a positioning shaft with a diameter that is precisely controlled to fit within a positioning hole. This dimensional parameter control ensures that thermal expansion or contraction of the drum frame does not affect the positioning accuracy, as the shaft-hole interface maintains its positional relationship through controlled dimensional tolerances.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If the process cartridge is mounted in the main casing with the developing cartridge in the drum cartridge, then the complete assembly can be operated, but positioning accuracy relative to the main casing degrades when the drum frame deforms

Engineering Contradiction:

Improveimage forming operationVSAvoidpositioning accuracy relative to main casing

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The positioning function is separated from the drum frame structure. A dedicated positioning shaft is introduced as an independent component that provides positioning reference, while the drum frame maintains its structural accommodation function. This segmentation allows the drum frame to deform thermally without affecting positioning accuracy, as the positioning shaft maintains its own dimensional stability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The positioning shaft acts as an intermediary element between the drum frame and the developing cartridge. It provides a stable positioning reference that mediates the relationship between these two components, ensuring accurate positioning even when the drum frame deforms due to thermal expansion or contraction.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9122236B2Photosensitive drum cartridge provided with positioning shaft

Publication Date: 2015.09.01 BROTHER KOGYO KK

AI summary

A photosensitive drum cartridge is configured to accommodate therein a developing cartridge having a developing roller and includes: a photosensitive drum; a drum frame; and a shaft. The photosensitive drum has an axis extending in an axial direction. The drum frame accommodates the photosensitive drum therein. The drum frame has a mounting portion configured to accommodate the developing cartridge therein. The shaft extends in the axial direction and includes a first abutment portion configured to be abutted on the developing cartridge when the developing cartridge is mounted in the mounting portion. The drum frame is formed with an exposure opening exposing the first abutment portion of the shaft.