| 摘要 |
PURPOSE:To measure accurate concentration by detecting the concentration of a liquid developer at a liquid film stop position from the quantity of transmitted light of a liquid film which almost disappears. CONSTITUTION:This measuring instrument is provided with a means which forms a liquid film 3 of a liquid developer with its own surface tension, a transmitted light quantity measuring means composed of a light emitting element 4 and a photodetecting element 5 for measuring the quantity of transmitted light of the liquid film, and a means which stops the liquid film of the liquid developer in the optical axis of the measuring means. When the liquid film of the liquid developer is stopped at a position coincident with the optical axis of the measuring means, the liquid film 3 become thinner with time and breaks to disappear eventually. The film thickness of the liquid film right before it disappears is extremely small, so the liquid film is relatively large in the quantity of transmitted light even when the light emitting element 4 in use has a small light emission output like an LED, so light easily measured. Consequently, the concentration of the liquid developer is detected on the basis of the quantity of transmitted light right before the liquid film disappears. Consequently, the concentration of the liquid developer is detected on the basis of the quantity of transmitted light right before the liquid film disappears to measure the concentration easily and accurately. |
