USB Control Endpoint Status Handling in Image Forming Equipment

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Solution Overview

Problem

Existing image forming apparatuses face issues in processing commands when print data is retained due to paper jams or consumable depletion, leading to unprocessed commands and communication bottlenecks in USB connections.

Innovation Solution

Implementing a USB interface with separate control and data endpoints, allowing for status requests and print cancellations to be transmitted through the control endpoint independently of data transfer, ensuring command processing even when print data is retained.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If print data and commands are transmitted over the same pipe, then data transfer efficiency is improved, but command processing capability deteriorates when print data is retained

Engineering Contradiction:

Improvedata transfer efficiencyVSAvoidcommand processing capability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The USB interface is segmented into multiple independent endpoints: a control endpoint for transmitting commands and status information, and a data endpoint for transmitting print data. This segmentation allows commands to be transmitted independently of print data, enabling command processing even when print data is retained in the pipe or on the image forming apparatus.

Inventive Principle:

Principle #1Segmentation

2Device complexity

If a single pipe is used for all transmissions, then interface complexity is reduced, but command processing reliability deteriorates during data retention

Engineering Contradiction:

Improveinterface complexityVSAvoidcommand processing reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The USB interface is divided into functionally distinct endpoints without requiring complex multiplexing or protocol layers. The control endpoint handles commands and status, while the data endpoint handles print data, achieving functional separation with minimal added complexity.

Inventive Principle:

Principle #1Segmentation

3Quantity of substance

If print data is retained in the pipe due to large volume or processing delays, then data transfer completeness is improved, but command transmission capability deteriorates

Engineering Contradiction:

Improvedata transfer completenessVSAvoidcommand transmission capability

Core Design Contradiction:

Quantity of substanceVSEase of operation

Solution Approach 1:

By separating command transmission through the control endpoint from data transmission through the data endpoint, the system ensures that command transmission is not blocked by retained print data. The control endpoint can independently transmit commands even when the data endpoint has unprocessed print data in its buffer.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20260029974A1Image forming apparatus transmitting status information to USB-connected terminal device via control endpoint of USB interface

Publication Date: 2026.01.29 BROTHER KOGYO KK

AI summary

An image forming apparatus includes a Universal Serial Bus (USB) interface and a controller. The USB interface includes a control endpoint for control transfer and a data endpoint for data transfer. The controller is configured to transmit, in response to receiving a status request command from a USB-connected terminal device through the control endpoint, status information of the image forming apparatus to the USB-connected terminal device through the control endpoint. The USB-connected terminal device is a terminal device connected to the image forming apparatus through a USB connection.