Skew Correction in Image Forming Apparatus via Optical Pattern Detection
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Solution Overview
Problem
Tandem color image forming apparatuses face challenges in correcting image positional deviations, leading to color shifts during the transfer of toner images onto a recording sheet due to misalignment and skew issues, which existing correction mechanisms struggle to accurately address.
Innovation Solution
An image forming apparatus equipped with a light beam scanner for scanning a pattern for image positional deviation correction, a developing device to develop the latent image, a transfer belt for transferring the pattern, a sensor for reading the pattern, a skew correction device to adjust optical members, and circuitry for driving the correction mechanism, allowing for precise skew correction and image positional deviation correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If image positional deviation correction is performed using conventional methods, then color shift is reduced to some extent, but manufacturing precision and measurement precision remain insufficient due to inaccurate detection and correction of skew and positional deviations
Solution Approach 1:
The patent replaces conventional mechanical sensor-based detection with optical field-based detection. A light beam scans the pattern for image positional deviation correction on the intermediate transfer belt, and the reflected or transmitted light is analyzed to determine pattern position. This optical substitution enables more precise measurement of the pattern's main scanning and sub-scanning positions without mechanical contact, thereby improving measurement precision and subsequently image positional accuracy.
Solution Approach 2:
The patent uses optical imaging to create a virtual copy of the pattern position information. By scanning the pattern with a light beam and analyzing the optical signal, the system creates an accurate digital representation of the pattern's actual position on the intermediate transfer belt. This optical copy allows for precise measurement and feedback control without physically touching or disturbing the pattern, improving both measurement precision and manufacturing precision.
2Manufacturing precision
If skew correction is performed by adjusting optical members during image formation, then image quality improves, but device complexity increases due to additional adjustment mechanisms and actuators
Solution Approach 1:
The patent performs skew correction before the main image formation process. The pattern for image positional deviation correction is first formed on the intermediate transfer belt, then its position and skew are detected using the light beam scanning method. Based on this detection, skew correction is applied by adjusting the light beam scanner's optical members. Only after this preliminary correction is the actual image formed. This preliminary action approach simplifies the overall system because the correction mechanism is activated only when needed, rather than being continuously active during all image formation operations.
Solution Approach 2:
The patent implements a feedback control loop for skew correction. The light beam scans the pattern on the intermediate transfer belt, detects its actual position and orientation, and this detection information is fed back to the control system. The control system then adjusts the optical members of the light beam scanner to correct any skew or positional deviation. This closed-loop feedback mechanism achieves high skew correction accuracy without requiring overly complex mechanical adjustment mechanisms, as the system self-regulates based on real-time optical detection.
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
The solution effectively reduces color shifts by accurately measuring and correcting skew and positional deviations, ensuring high-quality image formation by aligning toner images with precision, thereby improving the overall image formation process.
Implementation Method 1
a light beam scanner to scan an image bearer by a light beam according to data on a pattern for image positional deviation correction
Implementation Method 2
a sensor to read the pattern to obtain an amount of image positional deviation
Data Source
AI summary
An image forming apparatus includes a light beam scanner to scan an image bearer by a light beam according to data on a pattern for image positional deviation correction and a developing device to develop a latent image of the pattern. The pattern is formed on the image bearer by scanning performed by the light beam scanner. The image forming apparatus includes a transfer belt to transfer the pattern to a medium, a sensor to read the pattern to obtain an amount of image positional deviation, a skew correction device to adjust a tilt of an optical member of the light beam scanner according to a skew amount to correct a skew and perform the image positional deviation correction according to the amount of image positional deviation, and circuitry to drive the skew correction device before the image positional deviation correction.