Form-Fold Direction Sensor Assembly
Original Publication Date: 1989-Apr-01
Included in the Prior Art Database: 2005-Jan-27
For sensing the form-fold direction (mountain-valley) of continuous folding form paper in a printer, a pair of photosensors are provided on a V-shaped form guide at opposite sides with respect to the form to recognize and set the physical page length of the form. In Fig. 1, when the form is moved along the V-shaped form guide, each of the sensors mounted on the form guide provide an amplitude of output voltage depending on the distance between the sensor and the form so that the mountain or valley at the folding portion of the form can be sensed by checking the sensor output. To assure the reliability of sensing the distance, a pair of sensors are provided at the opposite sides with respect to the form, as shown in Fig. 2. Both sensors .