Pre-exposure Timing Control for Drum Life and ATVC Accuracy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing electrophotographic image forming apparatuses face challenges in extending the life of the photosensitive drum while maintaining the accuracy of active transfer voltage control (ATVC), as the direct-current charging scheme reduces discharge but still causes drum surface degradation, and pre-charge exposure can lead to non-uniform potentials and inaccurate ATVC.
Innovation Solution
An image forming apparatus with a preliminary exposing portion that adjusts the timing of pre-exposure relative to the ATVC operation, ensuring the pre-exposure starts after the abnormal discharge period ends, thereby maintaining uniform drum potential and extending the drum's life without compromising ATVC accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pre-charge exposure is performed to make drum potential uniform, then ATVC accuracy is improved, but abnormal discharge occurs causing non-uniform potential and reduced ATVC accuracy
Solution Approach 1:
The patent applies preliminary action by performing pre-charge exposure at an optimized timing before the ATVC measurement, ensuring the drum potential is uniformized in advance. The key innovation is controlling the interval between pre-charge exposure and ATVC to occur after any abnormal discharge has subsided, thus preparing the drum in an optimal state for accurate measurement without suffering from discharge-induced non-uniformity.
2Duration of action of stationary object
If direct-current charging is used to reduce discharge, then drum life is extended, but discharge still occurs causing surface degradation
Solution Approach 1:
The patent applies periodic action by using alternating-current superimposition charging instead of direct-current charging. The alternating current periodically reverses direction, which prevents continuous discharge in one direction and reduces cumulative damage to the drum surface. The superimposed AC voltage creates periodic charging cycles that extend drum life while minimizing surface degradation compared to continuous DC charging.
3Stability of the object's composition
If alternating-current superimposition charging is used to uniformly charge drum surface, then charging uniformity is improved, but discharge occurs frequently causing drum surface damage
Solution Approach 1:
The patent applies parameter changes by optimizing the timing parameters of the charging process. Specifically, it controls the interval between pre-charge exposure and ATVC measurement to occur after abnormal discharge has ended. This timing parameter adjustment allows the system to benefit from uniform charging while avoiding the harmful effects of discharge-induced surface damage.
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 effectively extends the life of the photosensitive drum by minimizing surface scraping and maintaining high transfer efficiency, preventing inappropriate transfer and drum surface damage, even in low-temperature and low-humidity environments.
Implementation Method 1
a preliminary exposing portion that exposes the image bearing body after the developer image is transferred and before the image bearing body is charged by the charging member
Implementation Method 2
a charging member that charges the image bearing body
Implementation Method 3
a transfer member that transfers a developer image formed by development, using a developer, of an electrostatic image formed by exposure of the charged image bearing body, from the image bearing body to a transferred body
Data Source
AI summary
An image forming apparatus includes an acquiring portion that acquires a duration of an overcharged state occurring in an area of an image bearing body charged by a charging member after the image bearing body is exposed by a preliminary exposing portion. Adjustment is made to an interval between a first timing when the preliminary exposing portion starts exposing the image bearing body before execution of an adjustment operation for setting a transfer voltage value and a second timing when a voltage applying portion starts, during the subsequent adjustment operation, applying a voltage with an adjustment voltage value to a transfer member such that the second timing is later than a third timing when the duration acquired by the acquiring portion ends.