Image Forming Apparatus Contact State Detection
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Solution Overview
Problem
Existing image forming apparatuses take a long time to determine whether the photosensitive drum and primary transfer member are in a state of contact or separation, which impairs usability, especially at the start of printing.
Innovation Solution
An image forming apparatus with a contact/separation unit that switches between contact and separation states, using a detection circuit to measure current and a control circuit to adjust voltage, allowing the processor to determine the state based on current behavior during voltage adjustment processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the contact/separation determination is performed by comparing current values after shifting to contact and separation states, then the determination accuracy is improved, but the time required for determination increases
Solution Approach 1:
The patent applies preliminary action by performing voltage adjustment processing before the actual toner image transfer operation. The control circuit adjusts the transfer voltage to a predetermined value in advance, and the processor determines contact/separation state based on current behavior during this preliminary voltage adjustment phase. This allows the determination to be made before the printing operation starts, eliminating the need to wait until after contact/separation switching occurs, thus reducing determination time while maintaining accuracy.
Solution Approach 2:
The patent replaces the mechanical approach of physically switching contact/separation states and then measuring current with an electrical field-based approach. The processor analyzes current behavior during voltage adjustment without requiring actual contact/separation switching. This substitution of mechanical state changes with electrical field analysis enables faster determination while maintaining measurement precision.
2Ease of operation
If the contact/separation determination is performed at the start of printing, then the usability is improved, but the initialization time increases
Solution Approach 1:
The patent performs the contact/separation determination during the voltage adjustment processing that occurs before toner image transfer. By determining the state during this preliminary phase rather than after contact/separation switching, the system enables rapid determination at the start of printing without adding to initialization time. The determination is integrated into the existing pre-transfer preparation sequence.
Solution Approach 2:
The patent maintains continuity of useful action by performing the determination during the voltage adjustment processing that is already part of the normal operation sequence. The current behavior analysis during voltage adjustment is a continuous process that occurs naturally before transfer, so no additional time is required. The useful action of voltage adjustment serves dual purposes: preparing for transfer and enabling state determination.
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
Enables rapid determination of the contact or separation state, reducing the wait time before starting printing and improving usability by accurately detecting the state without increasing the time required for initialization.
Implementation Method 1
a detection circuit capable of detecting a current flowing in the first transfer member and a current flowing in the second transfer member when the transfer voltage is applied to the first transfer member and the second transfer member
Implementation Method 2
a control circuit that executes voltage adjustment processing of adjusting a voltage output from the transfer power source so that the current detected by the detection circuit becomes a predetermined current value
Data Source
AI summary
A control circuit executes voltage adjustment processing of adjusting a voltage output from a transfer power source so that a current detected by a detection circuit becomes a predetermined current value. The voltage adjustment processing is executed before a toner image is transferred from at least one of a first image bearing member and a second image bearing member to an intermediate transfer belt. A processor determines whether the second transfer member is in a state of contact or is in a state of separation on the basis of behavior of the current detected by the detection circuit in a period in which the control circuit is executing the voltage adjustment processing.