Image reading apparatus having multiple wavelength light sources and control method for the same
US6501087B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 14, 2000 |
| Grant date | Dec 31, 2002 |
| Priority date | — |
| Expiry date | Apr 14, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07D7/121
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
To keep operation of a control circuit for a line sensor reading operation always the same regardless of variations and differences between readers, simplify the control circuit, and avoid complicated processes such as setting various software process parameters for canceling differences between the readers. A line shaped, two-wavelength transmitting LED array and a line shaped light emitting/photodetecting part comprising a photodetector array and a two-wavelength reflecting LED array are disposed in opposition each other such that a read medium passes between the two-wavelength LED array for transmitting light and the light emitting/photodetecting part, and the two-wavelength LED array for tranmitting light and two-wavelength LED array for reflecting light emit light of different wavelengths. An storage time control circuit is disposed in a signal processing circuit of the photodetector array; and a control means is provided for controlling light emission with the two-wavelength transmitting LED array and two-wavelength reflecting LED array, controlling reading with the photodetectors, and controlling the storage time control circuit. Variations in wavelength detection sensitivit…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.