Developing Unit Control for Image Forming Apparatus

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Solution Overview

Problem

In image forming apparatuses, the constant operation of developing devices during idle times between page formations leads to wasteful consumption of developers and decreased efficiency, especially when forming color images on both sides of a sheet.

Innovation Solution

An image forming apparatus with controllers that determine whether the estimated time until the next page formation is greater than a predetermined time, allowing the developing unit to be stopped during idle periods and restarted when necessary, optimizing developer usage and improving efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the developing device is constantly operated during vacant time, then the image forming apparatus is ready for immediate next image formation, but the developer is wastefully consumed

Engineering Contradiction:
Improvereadiness for immediate image formationVSAvoiddeveloper consumption
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The developing device dynamically adjusts its operational state based on real-time conditions. The controller monitors the vacuum state of the developing roller and transitions between operating modes (continuous operation, intermittent operation, or stop) depending on whether a subsequent sheet is detected, thereby optimizing both readiness and developer consumption

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system implements feedback control by detecting the presence of subsequent sheets and the vacuum state of the developing roller. This feedback information is used by the controller to make informed decisions about whether to maintain, interrupt, or stop developing device operation, ensuring optimal balance between readiness and resource conservation

Inventive Principle:
Principle #23Feedback

2Loss of substance

If the developing device is stopped during vacant time, then the developer consumption is reduced, but the image forming efficiency decreases due to frequent start-stop operations

Engineering Contradiction:
Improvedeveloper consumptionVSAvoidimage forming efficiency
Core Design Contradiction:
Loss of substanceVSProductivity

Solution Approach 1:

The developing device operates dynamically by switching between different operational states based on actual demand. Rather than fixed stop-start operation, the system adapts its behavior to the real-time presence of sheets, maintaining continuous operation when sheets are present and reducing operation only when vacant, thereby preserving productivity while reducing waste

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The developing device employs periodic monitoring and conditional operation. The controller periodically checks for the presence of subsequent sheets and adjusts operation accordingly, creating a rhythm of active and inactive periods that aligns with actual image formation needs, optimizing both efficiency and resource usage

Inventive Principle:
Principle #19Periodic action

3Loss of time

If the vacuum state of the developing roller is not maintained during stop, then the start-up time is reduced, but the developer may be contaminated or degraded

Engineering Contradiction:
Improvestart-up timeVSAvoiddeveloper quality
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The vacuum state management is dynamic rather than static. The controller maintains vacuum only when the developing device is operating or when a sheet is immediately expected, and releases vacuum when the device is stopped and no sheet is forthcoming. This dynamic approach minimizes both energy consumption and start-up time while preserving developer quality when needed

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3306405B1Image forming apparatus, method of controlling image forming apparatus, and carrier means
Publication Date: 2020.04.15 RICOH CO LTD
  • EP3306405B1 patent drawingFigure 1
  • EP3306405B1 patent drawingFigure 2
  • EP3306405B1 patent drawingFigure 3

AI summary

An image forming apparatus includes: an image forming device (110) to form a toner image onto a recording medium by transferring the toner image directly or indirectly onto the recording medium, the image forming device (110) including a developing unit (113) to develop a latent image formed on an image carrier into the toner image; a first controller (151) to determine whether a first estimated time period is greater than a first predetermined time period (T1), the first estimated time period being a time period from a time when image formation of one page of the image completes to an estimated time when image formation of a subsequent page of the image will start, and to stop operating the developing unit (113) based on a determination indicating that the first estimated time period is greater than the first predetermined time period; and a second controller (151) to determine, after determination of a time when image formation of the subsequent page of the image starts, whether an updated first estimated time period reflecting the determined time when image formation of the subsequent page of the image starts, is equal to or less than the first predetermined time period (T1), and to start operating the developing unit (113) based on a determination indicating that the updated first estimated time period is equal to or less than the first predetermined time period.