Disclosed is a scanner system which includes a light source and a photodetector. Circuitry is included for automatically adjusting the intensity of the light source so as to prevent saturation of the photodetector. Whenever the current through the photodetector exceeds a predetermined amount, a transistor switch is opened to connect a resistor in series with the light source and cause the intensity of the light source to decrease. When the output of the photodetector reduces due to decreased intensity of the light source, the transistor switch will close and thus cause the resistor to be bypassed and the intensity of the light source to return to its original level. The scanner is utilized to detect reference marks which are located on a contrasting background. Additional circuitry included to adjust the sensitivity of the system so as to be able to detect marks of varying contrast with respect to the background. A mark is determined to be present by detecting a predetermined amount of change in the output of the photodetector over a certain time period, which represents the change in reflectivity between a mark and the background. If the change in the photodetector exceeds the second predetermined level, a portion of the photodetector output is automatically shunted to ground, with a result that a greater change in the output in the photodetector is required to trigger the detection portion of the circuit. The portion of the output of the photodetector which is shunted is passed through a variable resistance. The resistance is determined by connecting one or more of a plurality of resistors into the shunt path by means of a multiplexer, the addressing of which is controlled by a counter.
A sheet carrying an image stored therein is scanned by a light beam emitted by a light source. Light which is obtained by the scanning of the sheet and which carries the image is detected by use of a photomultiplier. When the level of output current of the photomultiplier becomes higher than a predetermined standard level, the intensity of the light beam is decreased so that the level of the output current of the photomultiplier does not exceed the predetermined standard level, thereby preventing the photomultiplier from being broken by light of high intensity.
In active range finder apparatus wherein an object to be inspected is illuminated by a laser source and light reflected by the object is detected in an imaging photosensor, a system is provided for increasing the dynamic range of the apparatus. This system provides for integrating over each of a series of measuring time periods light reflected from a window of the photosensor and hence proportional to the light received by such photosensor. When such integrated light exceeds a predetermined amount, a saturation signal is generated that immediately de-energizes the source. If this amount is not reached by the end of each period, the system is reset. The source is gradually re-energized at the commencement of each subsequent period. The virtually instantaneous de-energization and gradual re-energization combined with use of a saturation detector separate from the main photosensor ensures rapid action that is quick enough to substantially avoid saturation of such main photosensor.
An optical scanner scans the surface of printed material at a particular position of the surface to determine if the surface is properly marked. The output level of the scanner at that position is compared with the output level of a differential signal level generator. If the two levels are substantially the same, then no error is indicated. If the two levels are different, then an error is indicated and the process is stopped to correct the error.
Novel strip chart recorders and strip chart recording paper are provided which are cooperable so that the recorder detects the proximity of a terminal edge of the paper, so that the recorder can signal this occurrence to the user enabling him to insert a new supply of strip chart paper in the recorder to avoid the loss of data. The recorder also cooperates with the strip chart paper to determine when paper is absent from the recorder, for example, when it has been exhausted, thereupon to signal this further occurrence to the user and take steps to avoid damage to the recorder which can result through its operation in the absence of paper in the recorder mechanism.
A method and apparatus are disclosed for preforming a heat-shrinkable member to a pre-selected configuration which may at least partially conform to a container to which the member is to be applied. The preformed member is subsequently applied to the container so that the member is retained in association therewith, such as for tamper-indication. The heat-shrinkable member is initially preformed by the use of a preforming mandrel which may be at least partially configured like the configuration of the container. After the member has been heat-shrunk on the preforming mandrel, it is positioned in association with the container, and thereafter heated so as to further conform the heat-shrinkable member to the configuration of the container. By this technique, hightly desirable control of the heat-shrinking process is achieved, thus assuring proper conformance of the heat-shrinkable member to its associated container. A further feature of the invention relates to final application of the preformed heat-shrinkable member by localized heating of the member, which desirably minimizes heating of the associated container and its contents.
