Plotter pen ink level detector
OwnerPaul C. Fisher, Jr., Wiebe H. Van Der Meer +1inventors
InventorsPaul C. Fisher, Jr., Wiebe H. Van Der Meer, Paul C. Fisher
Life of this patent
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Abstract
In a computer controlled automatic plotting device, an ink level detector is provided in a plotter pen cartridge. An ink-following object is provided in the plotter pin cartridge and is supported by the writing fluid. The ink-following object carries a magnet. As the ink-following object traverses down the inside of the plotter pen cartridge, the position of the magnet triggers a sensor at a predetermined level. The sensor then effects a visual or audible signal to alert an operator that the cartridge is running out of writing fluid. Alternatively, the sensor activates a control system to shut down the plotting device to permit replacement of the plotter pen cartridge with one having a new ink supply.
Claims14
A writing apparatus comprising:
- a) a hollow elongated cartridge, 23
- b) writing means located at an end portion of the cartridge, 30
- c) a column of writing fluid contained in the cartridge adjacent to the writing means, 26
- d) ink-following object means contained in the cartridge and supported by the writing fluid, 27
- e) magnet means carried by the ink-following object means;
- and 36
- f) means for sensing the location of the magnet means whereby the level of the column of writing fluid can be determined. 46
In combination with a computer-controlled automatic plotting apparatus, a plotter pen writing apparatus having means for stopping the operation of the plotter when the writing fluid is depleted to a predetermined quantity comprising:
- a) a hollow elongated housing,
- b) writing means located at an end portion of the
- cartridge,
- c) a column of writing fluid contained in the cartridge adjacent to the writing means,
- d) ink-following object means contained in the cartridge
- and supported by the writing fluid,
- e) magnet means carried by the ink-following object
- means;
- and
- f) means for sensing the location of the magnet means
- whereby when the writing fluid supply becomes depleted to a predetermined quantity the plotting
- device is automatically stopped to permit replacement
- of the writing fluid.
Apparatus for sensing the depletion of writing fluid in a plotter pen in a computer controlled automatic plotting device comprising:
- (a) a pen cartridge having an elongate hollow housing defining an internal chamber and having writing means mounted at an end portion thereof,
- (b) a quantity of writing fluid contained in the chamber,
- (c) ink-following object means supported by the writing fluid in the chamber,
- (d) magnet means carried by the ink-following object means,
- (e) means for sensing the location of the magnet means, said sensing means mounted exteriorly of the cartridge adjacent a lower portion thereof,
- (f) switch means activated by the magnet sensing means when the ink-following object means reaches a predetermined location in the cartridge, and
- (g) alert means for indicating a low writing fluid level condition in the cartridge.
Dependencies are inferred from the claim text.