In known types of manually operated silk screen printing apparatus, a hand-held squeegee is used to distribute ink across the screen and to force the ink through the screen onto the item to be printed in the pattern dictated by an intelligence pattern formed on the screen. While hand-held squeegees are inexpensive, even experienced printers, particularly when tired or distracted, sometimes fail to maintain a uniform pressure across the length of the squeegee blade during the printing stroke, resulting in an uneven print quality. Further, with hand-held squeegees, it is difficult to duplicate exactly the squeegee print action from one print to the next so that occasionally even consecutively-made prints may be non-uniform in quality. This is particularly noticeable in moderately long production runs of large-sized jobs.
Currently, manual silk screen printing units have been developed in which the squeegee blade is mounted on an elongated lever arm that is pivotally mounted at one end and that extends across the screen. The other end of the lever arm is a free or handle end that allows upward or downward movement of a squeegee carried on the lever arm to engage or disengage the screen. The squeegee is mounted on a carriage slideable along the lever arm when pushed and pulled by the operator through a print and flood stroke across the screen. Typically, the squeegee is pivoted on the carriage and the operator grasps the top of the squeegee with a hand on opposite sides of the lever arm and the carriage. The operator balances the amount of downward force exerted by each hand on the top of the squeegee to maintain the squeegee level and to try to exert uniform pressure on opposite halves of the squeegee blade onto the screen. The operator also adjusts the angle of incidence of the squeegee manually and tries to maintain a relatively uniform angle during an entire printing or flood stroke. The operator is free to adjust this angle during the stroke or between strokes and often inadvertantly makes such adjustments. That is, the operator is free to swing the squeegee to any angle of incidence with the screen, with the higher, more vertical angles for the squeegee exerting more force onto the screen to push the ink through the screen than when the squeegee is swung more toward the horizontal. The operator flips the squeegee between its print and flood strokes to an inclined angle of incidence between the flood and print stokes. In a typical, multi-arm, manual textile printer illustrated herein, the operator prints with the squeegee's lower end tilted away from the operator at the end of the level arm. At the end of the print stroke the operator turns the squeegee to an opposite inclination, with the lower end of the squeegee closer to the operator who is pushing the squeegee radially inwardly along the lever arm. Operators often have problems adjusting and maintaining this angle of incidence.
Manual operated silk screen printers are low in cost compared to automatic motor driven printers and any changes therein to produce better quality of printing or higher rates of production must be cost competitive to be commercially successful. Production from a manual silk screen printing press can be increased with the present invention by reducing the number of failures to achieve the quality of print needed and by reducing operator fatigue.
Accordingly, it is the primary object of the present invention to provide an improved, manual screen printing apparatus of the foregoing kind.
More particularly, it is an object to provide such an apparatus which is compact in size so as to be readily usable for printing small areas.
It is a further object to provide a manual screen printing apparatus that provides smooth, even and repeatable squeegee action across the screen which reduces operator fatigue and increases production from the apparatus.
Other objects and advantages will become apparent upon reference to the drawing and the detailed description of the preferred embodiment.