Abstract: An envelope reflectance meter for evaluating the contrast between ink on a pre-printed envelope and the envelope itself and for calculating and displaying the print contrast ratio and the print reflectance difference is described. The device includes a portable housing having internally a pair of light sources which generate a reflected image of the envelope. The image passes through a lens, is reflected from a mirror, and is then displayed on a viewplate. An aperture is provided in the viewplate which passes a beam of light. The beam of light is then split and the two beams resulting analyzed for red content and green content. The analog signal produced is then converted to digital and the print contrast ratio and print reflectance difference calculated. A display is provided within the housing adjacent the viewplate whereby selectively the values for red light and for green light and comparisons between the readings for ink and the readings for the envelope are selectively displayed for an operator.

Abstract: A stair climbing robot and method of operation is described. The robot includes a chassis having powered opposed front wheels and two pairs of rear wheels each pair being rotatably mounted on a beam at opposite ends thereof, and each beam being rotatably mounted on the chassis. A drive motor is provided for driving each pair of wheels in the same direction at a predetermined rotational velocity and a drive means is provided for simultaneously rotating the beams at a predetermined rotational velocity and in a predetermined direction. The method of operation to climb stairs includes the steps of activating the rotation of the beams in a forward direction while causing each pair of rear wheels to rotate in an opposite direction at the same rotational velocity. In this way, forward movement is achieved by action of the front wheels and the rotating beams and the rotational velocity of the rear wheels relative to the terrain will be zero.