Compact Input Gear Design for Developing Cartridge
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Solution Overview
Problem
Conventional developing cartridges face challenges in transmitting driving force reliably due to the compact size of components, leading to instability in the rotation of the supply roller and developing roller.
Innovation Solution
The design of a compact input gear with a specific configuration, including a connecting portion, gear portion, and flange portion, which is positioned to overlap with the partitioning wall, allows for stable engagement with the coupling member and transmission of driving force to the supply roller and developing roller gears, ensuring reliable rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the developing cartridge is made compact by reducing component sizes, then the cartridge size is reduced, but the input gear cannot reliably transmit driving force to the drive gears
Solution Approach 1:
The patent repositions the input gear in the widthwise direction (another dimension) to overlap with the partitioning wall, allowing the contact point with the coupling member to be located far from the rotational axis. This dimensional rearrangement enables the compact cartridge design while maintaining reliable driving force transmission through optimized gear geometry and contact point positioning.
2Volume of moving object
If the input gear is made smaller to fit compact cartridge design, then the cartridge size is reduced, but the contact point between input gear and coupling member cannot be positioned far enough from the rotational axis
Solution Approach 1:
The input gear is repositioned in the widthwise direction to overlap with the partitioning wall, utilizing the third dimension (width) rather than increasing radial size. This allows the contact point to be positioned far from the rotational axis in the radial direction while keeping the gear compact in overall dimensions, resolving the contradiction between gear size and contact point distance.
Solution Approach 2:
The input gear is divided into distinct functional portions: a connecting portion that contacts the coupling member, a gear portion with teeth, and a flange portion. This segmentation allows each portion to be optimized independently, with the connecting portion positioned to maximize contact point distance from the rotational axis while the gear portion remains compact for efficient tooth engagement.
Data Source
Figure 1
Figure 2A~2C
Figure 3
AI summary
A developing cartridge (17) is detachably mounted on a main casing (2) of an image-forming device (1). The main casing is provided with a coupling member (90) providing a driving force. The developing cartridge includes a developing roller (6), an input gear (40), and a transmission gear (41,42,43). The input gear includes a contact portion (81,181,281,381) that is in contact with the coupling member to receive the driving force and a gear portion (79). The input gear (40) rotates about a rotational axis defining an axial direction when the contact portion receives the driving force. The transmission gear (41,42,43) is meshingly engaged with the gear portion to transmit the driving force from the input gear (40) to the developing roller (6). The gear portion has a pitch circle defined by being meshingly engaged with the transmission gear. The pitch circle of the gear portion is arranged to overlap with the contact portion in the axial direction of the input gear (40).