Print Server Redundancy for Uninterrupted Pull Printing

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Solution Overview

Problem

Existing pull print systems fail to execute printing jobs if the print storing device is stopped, as they rely on communication with a pull print server and cannot continue printing if the server is unavailable after the job is transmitted.

Innovation Solution

A print system configuration with multiple print servers and shared databases/folders, managed by a central server, allows job information and data to be stored and shared across groups, enabling one print server to take over from another in case of failure, ensuring continuous printing operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single print server is used to store and manage print jobs, then the system structure is simple and easy to manage, but the system reliability deteriorates because printing cannot continue if the server is stopped

Engineering Contradiction:
Improveprinting continuityVSAvoidsystem structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system divides the print server functionality into multiple independent print servers (first print server and second print server) that can operate autonomously. Each server can store and manage print jobs independently, so when one server stops, the other can continue processing jobs, ensuring printing continuity without requiring a complex centralized architecture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes the operational state parameter of the print servers by allowing them to dynamically switch between active and inactive states. When a print server stops, the system detects this state change and redirects job requests to the other available server, maintaining service availability without structural redesign.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If print job information is stored locally on each print server, then each server operates independently and simply, but information sharing between servers is poor leading to job loss when a server stops

Engineering Contradiction:
Improvejob information availabilityVSAvoidinformation sharing mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system introduces an image forming apparatus as an intermediary that receives print jobs from the terminal apparatus and can directly access either print server. When the first print server stops, the image forming apparatus can retrieve jobs from the second print server or receive jobs directly, acting as a mediator that ensures job information availability without requiring complex inter-server communication protocols.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The terminal apparatus is configured to store port information for communicating with the image forming apparatus in advance. This preliminary action ensures that when a print server stops, the terminal can immediately redirect jobs through the image forming apparatus to the available server without requiring complex real-time negotiation or information sharing mechanisms between servers.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If the system relies on communication with a pull print server for all printing operations, then centralized control is achieved, but productivity deteriorates because printing stops completely when the server is unavailable

Engineering Contradiction:
Improveprinting efficiencyVSAvoidcommunication architecture
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system implements dynamic communication paths where the terminal apparatus can switch between centralized (through pull print server) and decentralized (direct to image forming apparatus) modes. When the pull print server is available, centralized control is used; when it stops, the system dynamically redirects communication to maintain printing efficiency without requiring permanent complex architecture.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system ensures continuous printing capability by establishing alternative communication paths. The terminal apparatus stores port information for direct communication with the image forming apparatus, enabling printing to continue uninterrupted when the pull print server is unavailable, thus maintaining productive action without permanent dual-architecture complexity.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP3528105B1Print system, print server, management server, job list providing method, and carrier means
Publication Date: 2021.12.08 RICOH CO LTD
  • EP3528105B1 patent drawingFigure 1
  • EP3528105B1 patent drawingFigure 2
  • EP3528105B1 patent drawingFigure 3

AI summary

A print system (1) includes print servers (12) that each store a print job, a management server (10) that manages the print servers, a printer (20) that performs printing of the print job, a print server information storing unit (33) that stores print server information, a shared information storing unit (14) that stores information of the print job, and a shared data storing unit (16) that stores data of the print job. The print servers each include a processor (506) that receives a job list request from the printer, acquires the information of the print job in a first group of the each of the print servers from the shared information storing unit, acquires the information of the print job in a second group different from the first group from at least one of the print servers in the second group, and provides a job list to the printer.