Developer Conveyance Device Pumping Strategy

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Solution Overview

Problem

Existing developer conveyance devices using positive-displacement pumps face challenges with increased conveyance load and bulkiness due to the need for higher pressure and larger sizes to handle varying distances and lifting heights of developer, leading to increased costs and reduced operational life.

Innovation Solution

A developer conveyance device with a positive-displacement pump that alternately generates positive and negative pressure, ensuring Qp>Qd, where Qp is the volume moved by a single pumping action and Qd is the volume in the developer reservoir, allowing for efficient transport with a compact design by maintaining a balance between developer and air in the conveyance channel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the pump size, rotational frequency, or stroke is increased to increase the capacity of the positive-displacement pump, then the pump can transport more developer, but the device becomes bulkier and the cost increases

Engineering Contradiction:
Improvepump capacityVSAvoiddevice size
Core Design Contradiction:
ProductivityVSVolume of moving object

Solution Approach 1:

The patent applies periodic action by controlling the pump to operate in intermittent cycles rather than continuously. The pump operates at high speed only when the conveyance channel requires developer replenishment, then stops to allow air to clear the channel. This periodic operation pattern maintains high productivity during active pumping while avoiding the need for a continuously running large-capacity pump, thereby reducing device size and cost.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent implements dynamics by making the pump operational parameters variable rather than fixed. The pump's rotational frequency and operational state (on/off) are dynamically adjusted based on the real-time developer level in the conveyance channel. This dynamic control allows a smaller pump to achieve the same effective capacity as a larger continuous pump by operating at higher speeds only when needed.

Inventive Principle:
Principle #15Dynamics

2Productivity

If the pump size or rotational frequency is increased to increase the capacity, then more developer can be transported, but the device becomes bulkier and cost increases

Engineering Contradiction:
Improvepump capacityVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent employs feedback control where the operational state of the pump is determined by the developer level in the conveyance channel. When the developer level drops below a threshold, the pump activates to replenish it; when the level is sufficient, the pump stops. This feedback mechanism allows a simpler, smaller pump to maintain optimal productivity without requiring complex mechanical designs or high continuous capacity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system achieves self-service through automatic pump control based on developer level detection. The pump autonomously activates and deactivates according to the conveyance channel's needs without external intervention, eliminating the need for complex external control systems and reducing overall device complexity while maintaining productivity.

Inventive Principle:
Principle #25Self-service

3Quantity of substance

If a large amount of developer is present in the conveyance channel, then the conveyance channel is filled with developer, but the amount of force required for transporting developer increases

Engineering Contradiction:
Improveamount of developer in conveyance channelVSAvoidconveyance load
Core Design Contradiction:
Quantity of substanceVSForce

Solution Approach 1:

The patent applies periodic action by operating the pump in intermittent cycles rather than continuously. The pump operates at high speed only when the conveyance channel requires developer replenishment, then stops to allow air to clear the channel. This periodic operation pattern maintains high productivity during active pumping while avoiding the need for a continuously running large-capacity pump, thereby reducing device size and cost.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent implements dynamics by making the pump operational parameters variable rather than fixed. The pump's rotational frequency and operational state (on/off) are dynamically adjusted based on the real-time developer level in the conveyance channel. This dynamic control allows a smaller pump to achieve the same effective capacity as a larger continuous pump by operating at higher speeds only when needed.

Inventive Principle:
Principle #15Dynamics

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 reduces conveyance load, enhances efficiency, extends the operational life of the device, and maintains a compact design while preventing toner coagulation by fluidizing the developer with air.

Implementation Method 1

a positive-displacement pump to alternately generate positive pressure and negative pressure by varying a volume of space therein to transport developer from the developer reservoir to a destination

Methodology Applied
Scientific EffectPositive-displacement pump mechanism: Pump

Implementation Method 2

preventing toner coagulation by fluidizing the developer with air

Methodology Applied
Scientific EffectFluidization: Fluidisation

Data Source

PatentEP2733550B1Developer conveyance device and image forming apparatus
Publication Date: 2020.01.01 RICOH CO LTD
  • EP2733550B1 patent drawingFigure 1
  • EP2733550B1 patent drawingFigure 2
  • EP2733550B1 patent drawingFigure 3

AI summary

A developer conveyance device (48) includes a developer reservoir (54) for containing developer, having a developer outlet (54a) at a bottom portion thereof, and a positive-displacement pump (56) to alternately generate positive pressure and negative pressure by varying a volume of space therein to transport developer from the developer reservoir (54) to a destination. When Qp represents a volume of developer moved by a single pumping action of the pump (56), calculated by multiplying a maximum flow amount of the pump (56) per unit time by an operation time of the pump (56); Qd represents a volume of developer contained in the developer reservoir (54); and Qe represents a volume of developer present in a virtual columnar space (K) defined by vertically raising the developer outlet (54a) to a level of developer contained in the developer reservoir (54), either Qp>Qd or Qp>Qe is satisfied.