Offline Print Credit Management in Image Forming Apparatus

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Solution Overview

Problem

Conventional image forming apparatuses cannot supplement credits or determine remaining print credits effectively in offline states, leading to incomplete print jobs despite available credit, causing inconvenience to users.

Innovation Solution

The image forming apparatus includes a controller that manages print page counts by incrementing a printed page number counter for each printed sheet, determining if it exceeds an upper limit, and inhibiting further printing when the limit is reached, while resetting the counter when reconnecting to the network.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the image forming apparatus operates in an offline state without network connection, then the apparatus can continue printing without requiring constant internet connection, but the credit cannot be supplemented from the subscription server and the print page determination becomes inaccurate

Engineering Contradiction:
Improveprinting continuityVSAvoidcredit amount accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by pre-defining a second upper limit page number for offline operation before the actual printing occurs. The controller stores this pre-calculated limit in memory and uses it to determine when to stop printing in offline mode, eliminating the need for real-time credit verification from the network while ensuring accurate print page management.

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If the image forming apparatus determines credit sufficiency on a print-job basis, then the determination process is simple, but printing cannot be completed when the remaining credit is insufficient to complete the entire print job even though credit remains for partial printing

Engineering Contradiction:
Improvecredit determination processVSAvoidprint job completion
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The patent segments the credit determination into two distinct thresholds: a first upper limit page number for general credit checking and a second upper limit page number specifically for offline operations. This segmentation allows the system to apply different determination rules for different operating modes, ensuring that partial printing with remaining credit is properly handled while maintaining simple overall control logic.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If the image forming apparatus allows printing until the first upper limit page number is reached, then users can print as much as their contract allows, but the apparatus cannot distinguish between offline and online credit limits leading to potential over-printing or incomplete printing

Engineering Contradiction:
Improvecredit limit flexibilityVSAvoidprint page control accuracy
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality by assigning different upper limit values to different operating conditions. The first upper limit page number applies to online operations where credit can be supplemented, while the second upper limit page number applies specifically to offline operations. This localized differentiation ensures that the appropriate credit limit is enforced based on the current network status, improving both adaptability and reliability.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4127836B1Image forming apparatus and method for controlling image forming apparatus
Publication Date: 2025.01.08 BROTHER KOGYO KK
  • EP4127836B1 patent drawingFigure 1
  • EP4127836B1 patent drawingFigure 2
  • EP4127836B1 patent drawingFigure 3~4

AI summary

An image forming apparatus includes a main body memory, and a controller. A second upper limit information stored in the main body memory indicates an upper limit of a printable page number that the image forming apparatus is allowed to print in a state where the image forming apparatus is in an off-line state. A printed page number information stored in the main body memory indicates a printed page number printed in the off-line state. The controller is configured to: increment the printed page number information by one in a case where the one sheet of paper is printed on one side printing; and increment the printed page number information by two in a case where the one sheet is printed on double-sided printing. The controller is configured to determine whether the printed page number information is greater than or equal to the second upper limit page number.