Print Inspection Control for Cross-Sheet Defect Position Correction
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Solution Overview
Problem
Conventional image defect diagnosis techniques in image forming apparatuses fail to accurately identify the cause of defects due to shifts in the main scanning position caused by sheet tilting or reciprocating control, leading to erroneous determinations of image defects.
Innovation Solution
An inspection system and method that includes a reading device to detect image defects and diagnose failure locations by determining a shift amount of the recording sheet, allowing accurate detection and identification of image defects based on a detection target region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If reciprocating control is executed to prevent damage to intermediate transfer belt or fixing unit by paper edges, then damage prevention is improved, but main scanning position shifts across pages causing image defects to be misattributed
Solution Approach 1:
The patent introduces a position correction mechanism that acts as an intermediary between the reciprocating control system and the inspection system. This mechanism includes a position detection unit that detects the actual main scanning position and a correction unit that calculates and applies position correction based on the detected position and pre-stored reciprocating control information, thereby eliminating the mismatch between expected and actual positions
Solution Approach 2:
The patent implements a feedback loop where the position detection unit continuously monitors the actual main scanning position during inspection, compares it with the expected position based on reciprocating control settings, and provides correction information back to the inspection system. This feedback mechanism enables real-time adjustment to maintain measurement precision despite reciprocating control variations
2Ease of operation
If feature amounts are extracted based on corners of recording sheet, then inspection simplicity is improved, but shift in main scanning position causes erroneous determination of image defect causes
Solution Approach 1:
The patent introduces a position correction mechanism that acts as an intermediary between the simple corner-based inspection method and the reliable defect cause identification. This mechanism includes a position detection unit that detects the actual main scanning position and a correction unit that calculates and applies position correction based on the detected position and pre-stored reciprocating control information, thereby eliminating the mismatch between expected and actual positions
Solution Approach 2:
The patent performs preliminary position correction calculations before the actual defect analysis. The correction unit pre-calculates the position correction values based on the detected main scanning position and the pre-stored reciprocating control information, so that when defect analysis is performed, the corrected positions can be directly applied to accurately identify defect causes without complicating the overall inspection process
Data Source
AI summary
An inspection system including a printing apparatus, an inspection apparatus, and controllers to cause a reading device to read a printed matter, for which the printing apparatus has printed an image on a recording sheet, to obtain image data, to obtain a shift amount between a preceding first recording sheet and a following second recording sheet in a direction orthogonal to a conveyance direction of a recording sheet used for printing, to detect an image defect in the obtained image data, and to diagnose a failure location of the printing apparatus based on an inspection detection result. The diagnosis determines whether a continuous image defect has occurred based on a position of an image defect in the preceding first recording sheet and a position of an image defect in the following second recording sheet. The obtained shift amount and the failure location are diagnosed based on the determined image defect.