Polygon Motor Speed Control for First Print-Out Time

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Solution Overview

Problem

The start-up time of polygon motors in electrophotographic image forming apparatuses is significantly longer at lower ambient temperatures, leading to increased first print-out times due to the temperature dependence of oil dynamic bearings, which complicates the control of paper feed timing and delays image formation.

Innovation Solution

An image forming apparatus equipped with a temperature sensor and controller that adjusts the rotational speed of the polygon motor and paper feed mechanism based on ambient temperature, allowing pre-rotation at a lower speed before increasing to rated speed and synchronizing paper feed timing with the expected start-up time of the polygon motor, thereby reducing the first print-out time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the paper feed start timing is set using the longest start-up time of the polygon motor as reference, then the polygon motor can start up completely without paper reaching transfer position early, but the first print-out time becomes excessively long when operating under environmental conditions where the start-up time is relatively short

Engineering Contradiction:

Improvepolygon motor start-up completionVSAvoidfirst print-out time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The polygon motor performs preliminary rotation at a standby rotational speed before image formation operation. This preliminary action allows the motor to be pre-positioned and reduces the acceleration time required when image formation is commanded, thereby shortening the first print-out time while ensuring reliable start-up completion.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The rotational speed of the polygon motor is made dynamic rather than fixed. The motor operates at a lower standby rotational speed during idle periods and accelerates to a higher operational rotational speed when image formation is required. This dynamic speed adjustment optimizes both reliability and response time.

Inventive Principle:

Principle #15Dynamics

2Loss of time

If the polygon motor rotates at a lower standby rotational speed before image formation, then the first print-out time is reduced, but the motor requires additional acceleration time to reach rated speed

Engineering Contradiction:

Improvefirst print-out timeVSAvoidacceleration time

Core Design Contradiction:

Loss of timeVSDuration of action of moving object

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The rotational speed parameter of the polygon motor is changed based on operational state. The motor operates at a lower standby rotational speed during idle periods and accelerates to a higher operational rotational speed when image formation is required. This parameter change optimizes both response time and acceleration efficiency.

Inventive Principle:

Principle #35Parameter changes

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 approach enables earlier image formation by optimizing the start-up process based on ambient temperature, reducing the time required for the polygon motor to reach rated speed and ensuring timely paper feed, thus expediting the image formation process across varying temperature conditions.

Implementation Method 1

a temperature sensor that detects an operating ambient temperature of the polygon motor

Methodology Applied

Scientific EffectTemperature sensing:

Implementation Method 2

A polygon motor having an oil dynamic bearing is widely used as a rotary drive source for a laser scanner. This type of polygon motor has temperature dependence attributable to the viscosity of oil.

Methodology Applied

Scientific EffectOil dynamic bearing temperature dependence:

Data Source

PatentUS8941701B2Image forming apparatus and method for controlling the image forming apparatus

Publication Date: 2015.01.27 KONICA MINOLTA BUSINESS TECH INC

AI summary

An image forming apparatus includes a temperature sensor detecting an operating ambient temperature of the polygon motor, and a controller controlling the polygon motor and the paper feed mechanism. If the temperature detected by the temperature sensor is equal to or greater than a preset temperature, the controller controls, before operation for giving a command to start image formation is performed, the polygon motor to rotate; increases, in response to the operation, a rotational speed of the polygon motor up to a rated speed; and controls the paper feed mechanism to start conveying a sheet of paper at a time when a period of time variable depending on the detected temperature has elapsed, the period of time being preset to be shorter as the detected temperature increases, in expectation of a time required for the rotational speed of the polygon motor to reach the rated speed.