Lighting Device with Linear Irradiation Port for Density Measurement
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Solution Overview
Problem
Conventional inline density measuring devices require re-creation of conversion formulas whenever the print job is switched, leading to low efficiency due to the influence of peripheral patterns on image data captured by cameras.
Innovation Solution
A lighting device that irradiates only the inspection region on a sheet or web with linear light, using a light source and an irradiation port formed between parallel plate members, allowing for accurate color measurement without peripheral pattern influence, and an inspection device that captures color bars, acquires measurement values, and determines quality using stored correction values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the camera captures the color bar without light shielding, then the inspection device can obtain image data for density measurement, but the image data is influenced by peripheral patterns causing measurement inaccuracy
Solution Approach 1:
The patent extracts and removes the harmful peripheral pattern interference from the image data by introducing a light shielding member with an irradiation port. This member blocks light from reaching peripheral patterns while allowing light to illuminate the color bar, thereby extracting only the necessary measurement information without contamination from surrounding patterns.
Solution Approach 2:
The light shielding member acts as an intermediary element between the light source and the inspection target. It selectively controls light transmission, allowing light to reach the color bar through the irradiation port while blocking light that would otherwise illuminate peripheral patterns and contaminate the image data.
2Measurement precision
If the conversion formula is re-created for every print job change, then accurate density measurement can be maintained, but the efficiency of switching print jobs becomes low
Solution Approach 1:
The patent performs preliminary action by creating and storing a conversion formula in advance using a standard reference pattern. When a print job changes, the system can directly use the pre-created conversion formula without re-creation, thereby maintaining measurement accuracy while improving switching efficiency. The light shielding member ensures that the reference pattern measurements remain consistent and free from peripheral interference.
3Adaptability or versatility
If the camera captures a wide area including peripheral patterns, then the inspection device can capture the color bar, but the color measurement value becomes different from the reference value
Solution Approach 1:
The patent applies local quality by creating a localized illumination environment through the light shielding member with its irradiation port. This member concentrates light precisely on the color bar area while blocking light from reaching peripheral regions. The irradiation port's linear opening in the widthwise direction ensures that only the necessary inspection region receives light, creating a locally optimized measurement environment.
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 efficient switching of print jobs by eliminating the need to re-create conversion formulas, ensuring accurate density measurements and maintaining high inspection performance without interference from peripheral patterns.
Implementation Method 1
the irradiation port is formed between parallel portions where a first plate member and a second plate member parallelly face each other, and one of the sheet and the web under conveyance is irradiated with linear light
Data Source
AI summary
A lighting device (23) irradiates a web under conveyance with light. The lighting device includes a light source (43), and an irradiation port (61) configured to open linearly in a widthwise direction of the web at an end portion facing the web. The irradiation port (61) is formed between first and second parallel portions (62b, 63b) where a first plate member (62) and a second plate member (63) parallelly face each other. The web under conveyance is irradiated with linear light. It is possible to provide a lighting device capable of irradiating only an inspection region of a sheet or a web with light.