Image Forming Apparatus Boundary Density Control
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Solution Overview
Problem
In image forming apparatuses using multiple units, variations in charge amount lead to differences in image density between units, causing conspicuous boundaries and an unnatural impression in large-format prints.
Innovation Solution
The apparatus includes multiple image formers capable of forming overlap and non-overlap images, with a hardware processor controlling the units to reduce density differences at boundaries by adjusting gradation values and blurring techniques, ensuring seamless integration of images across units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple image formers are arranged in the main scanning direction to form large sheet images, then the ability to print on large sheets is improved, but image density variations occur at boundaries between images formed by different units
Solution Approach 1:
The patent applies parameter changes by adjusting the charge amount of the developing agent in each image former. Specifically, the charge amount is varied to compensate for density differences at boundaries, ensuring uniform image density across the entire large sheet output. This is achieved by controlling the developing charge parameters differently for overlap and non-overlap regions.
Solution Approach 2:
The patent implements local quality by applying different developing conditions to different regions of the image formers. Overlap image formers and non-overlap image formers use different charge amounts, and within each unit, different scanning regions (overlap vs non-overlap areas) receive tailored charge adjustments. This localized control ensures seamless blending at boundaries.
2Productivity
If multiple image formers are used to form images on large sheets, then productivity for large format printing is improved, but boundaries between images become conspicuous due to density differences
Solution Approach 1:
The patent changes operating parameters of the developing agents in different image formers, specifically adjusting charge amounts to ensure that images from multiple units have consistent density characteristics. This parameter adjustment eliminates conspicuous boundaries while maintaining high productivity for large sheet printing.
Solution Approach 2:
The patent employs feedback mechanisms where the system monitors and adjusts charge amounts based on the specific configuration of overlap and non-overlap image formers. This feedback control ensures that density variations are compensated in real-time, maintaining image quality consistency across multiple image forming units.
3Illumination intensity
If charge amount of developing agent is increased to improve image density, then image darkness is improved, but boundaries between images from different units become more conspicuous
Solution Approach 1:
The patent applies different charge amounts to different image formers and regions. Specifically, overlap image formers and non-overlap image formers use different charge levels, and within each unit, the charge is adjusted based on whether the region is an overlap or non-overlap area. This localized differentiation ensures uniform boundary appearance while achieving desired overall image density.
Solution Approach 2:
The patent optimizes charge amount parameters to balance image density and boundary visibility. By carefully controlling the charge parameters in each image former, the system achieves sufficient image darkness while preventing conspicuous boundaries through precise parameter differentiation across units.
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 solution reduces the visibility of boundaries between overlap and non-overlap images, resulting in a natural-looking large-format print with minimized density and gloss differences, preventing conveyance failures and wrinkles.
Implementation Method 1
irradiate (expose) a charged photoconductor drum (image bearing member) with (to) laser light based on image data to form an electrostatic latent image
Implementation Method 2
The electrostatic latent image is then visualized by supplying toner from a developing device to the photoconductor drum on which the electrostatic latent image is formed
Implementation Method 3
heat and pressure are applied to the sheet at a fixing nip to form a toner image on the sheet
Data Source
AI summary
An image forming apparatus includes a plurality of image formers each capable of forming, on a sheet, an overlap image and a non-overlap image, a fixer that fixes, on the sheet, a whole image composed of the overlap images and the non-overlap images, and a hardware processor that controls each of the plurality of image formers such that a difference in image at a boundary between the overlap image and the non-overlap image is reduced in the whole image.