Optical Roll-Up State Detection for Inkjet Printers
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Solution Overview
Problem
Conventional methods fail to accurately detect roll-up errors in inkjet printing apparatuses when rolling up roll paper, leading to potential damage and degradation of printed images, especially for larger or irregularly sized media.
Innovation Solution
A non-contact sensor system, such as an infrared LED and light-receiving sensor, is used to detect the roll-up state of the printing medium without contacting the printed surface, allowing for real-time error detection and control of the roll-up process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a photo-interrupter detects the rotation of an encoder scale to detect the paper feed state, then the roll-up control can be adjusted, but the system cannot detect when roll paper suffers strong pull or when the printed surface contacts rollers
Solution Approach 1:
A reflective member is introduced as an intermediary element that reflects light from the light source to the light-receiving sensor. This intermediary allows non-contact detection of the roll-up state by monitoring changes in light reflection caused by the printing medium's position and tension, enabling detection of errors such as strong pull or printed surface contact without directly measuring the paper itself.
Solution Approach 2:
The patent replaces mechanical contact-based detection (encoder scale rotation detection) with an optical detection system (light source and light-receiving sensor). This substitution enables non-contact measurement of the roll-up state, providing more precise error detection capability while avoiding the limitations of mechanical systems that cannot detect certain error conditions.
2Speed
If roll paper is pulled toward the roll-up side by setting the rotational speed of the motor on the roll-up side faster than that on the printing side, then roll-up speed is improved, but strong pull on the roll paper cannot be detected
Solution Approach 1:
The light-receiving sensor provides continuous feedback on the roll-up state by detecting changes in light reflection from the reflective member. This feedback mechanism monitors the actual roll-up process in real-time, detecting anomalies such as strong pull or improper rolling even when the motor operates at higher speeds, thereby maintaining reliability while achieving improved roll-up speed.
3Measurement precision
If a guide is arranged at the slack generating portion for stable detection by the sensor, then detection stability is improved, but the printing medium cannot be moved along the guide immediately after printing
Solution Approach 1:
The reflective member serves as an intermediary that enables optical detection without requiring physical guides to contact or constrain the printing medium. The light-based detection system achieves stable measurement by monitoring optical properties of the reflective member and printing medium interaction, eliminating the need for mechanical guides that would restrict handling flexibility.
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 enables reliable detection of roll-up errors, prevents damage to the printed medium, and maintains print quality by avoiding direct contact with the printed surface, effectively handling various sizes and types of printing media.
Implementation Method 1
a light source 12 and a light-receiving sensor 14 for detecting light emitted by the light source 12 are arranged in the stand 3
Data Source
AI summary
This invention is directed to a printing apparatus and printing medium roll-up state discrimination method of printing using a rolled printing medium while reliably rolling up the printing medium after printing and accurately detecting a roll-up error. This printing apparatus prints on a rolled printing medium, rolls it up in accordance with the discharge operation of the printing medium after printing, and optically detects the roll-up state of the printing medium upon roll-up. The printing apparatus discriminates an abnormality in the roll-up state of the printing medium on the basis of the detection result.