Patent Application
20090095174
This invention relates, generally, to silk screening devices; more particularly, to multi-color silk screening devices that utilize a pressure mechanism and pin-lock alignment system in order to achieve efficient and consistent production of sample materials.
The art of silk screening or screen printing has been used by printers for many decades in order to produce multiple copies of identical images on paper, garments, and other such articles. Designers of silk screening devices have sought to improve upon the consistency and speed with which multi-colored images could be produced on the devices. Specifically, they have sought to make improvements on the inconsistencies created when different machine operators applied different pressures to the screen squeegee and the distortions caused by misalignment of screens for applying different colors to the fabrics. While these problems have been somewhat rectified in many expensive, automated, mass-production devices known in the art, there remains a need for a manually operated device that can produce consistent high-quality sample articles on a silk screen printing device.
In silk screen printing operations, a squeegee containing an ink is moved across a stencil such that the open areas of the stencil allow ink to be transferred to the open areas of the article to be printed upon, below. By using multiple stencils and different colored inks, applied onto a single article, the operation is able to produce multi-colored prints on a single article. One problem encountered in manually operated silk screening devices is different passes of the squeegee will apply differing degrees of pressure at different angles, thus, resulting in prints with inconsistent darkness and overall appearance. These inconsistencies naturally result as different operators apply different pressures, depending on their weight and muscle strength, and, even with the same operator, pressure variations depending on fatigue or other factors. Such inconsistencies in pressure are undesirable because the produced articles of varying colors do not appear uniform in quality. Also, when manually preparing samples prior to mass production on an automated machine, the user is not able to accurately reflect the pressure and appearance that will be produced in mass-produced articles because the user cannot match the pressure to that of the mass production machine nor can the pressure be quantified and documented.
In order to regulate squeegee pressure, several devices have employed pneumatic pressure systems in order to eliminate the inconsistencies that would occur when different machine operators use the same machine. For example, U.S. Pat. No. 4,995,316 to Kolblin discloses a screen printing machine that includes a pressure cylinder that allows the operator to control the pressure between the squeegee and the table. Because Kolblin's device employs a complex dual-cylinder mechanism, however, it is not well suited to inexpensive and easily operated devices used in producing sample products manually.
Another such device is disclosed by U.S. Pat. No. 4,079,671 to Dubuit, which teaches a screen-printing machine for printing onto an article by using a pneumatically actuated squeegee. Dubuit's device, however, is pneumatically actuated and thus, not well suited to manual production of sample articles in low-quantities. Another such device is taught by U.S. Pat. No. 4,696,228 to David et al., which teaches a silk screen device using a cantilevered support frame to hold a screen that includes a pneumatically actuated bladder. The pneumatic bladder in David's device, however, is used to position the bladder but does not assure that the pressure applied to the squeegee is consistent.
A silk-screen device employing a powered squeegee device is disclosed by U.S. Pat. No. 5,309,831 to Fuqua et al. The Fuqua disclosure, however, is for an elaborate and expensive mechanism that is better suited to mass-production of articles than the manual production of a limited number of samples. U.S. Pat. No. 6,817,288 to Flatt also discloses a screen printing apparatus that utilizes pneumatic devices. In Flatt's device, print screens are held in place by pneumatically actuated clamping devices. The clamping devices, however, do not assure that each article printed on the silk screen is printed with consistent squeegee pressure.
Thus, there remains a long-felt need in the art for a manually operated silk screen press that utilizes pneumatic controls to regulate the press' squeegee pressure to ensure the consistent production of articles.
Meanwhile, several inventions have sought to improve distortions in the printed image that result from misalignment of multiple colored screens used on the same silk screen device. These distortions may arise when, in performing multi-color silk screening using multiple stencils, the stencils are not properly aligned for each pass of the squeegee.
One such invention is disclosed by U.S. Pat. No. 5,648,189 to Newman. Newman's patent teaches a pin registration bar of aligning an image film of a screen printing frame. The registration bar includes a plurality of pins that project upwards and downwards to provide a means to align the film to the printing frame. In this manner, the pin registration bar ensures that the plurality of stencils placed on the machine use the same alignment relative to the frame. Another such device is disclosed by U.S. Pat. No. 5,226,366 to Schlife et al. Schlife's device teaches a pin registration system for aligning stencils on a silk screen frame via numerous members attached to the screen frame that attach the silk screen stencil. Both of these devices, however, are complex, requiring numerous parts and manufacturing steps in order to fabricate.
Thus, there remains a long-felt need in the art for a manual silk screen press that allows the pressure applied by the squeegee to be pneumatically regulated, includes an alignment device such that multi-colored images are properly aligned when produced by the machine, and meets the need of easy and expedient changing of the squeegee from color to color.
This invention is directed towards overcoming the above shortcomings and teaching a manually operated silk screen press that utilizes actuating mechanisms to regulate the pressure and angle of the squeegee and a pin registration device that maintains the alignment of multiple stencils used for multi-colored images, thereby, removing ergonomic challenges.
The device comprises a frame that mounts the many components of the device. A horizontal platform attached to the frame holds the article in place which is to be silk-screened under the silk screen squeegee. The invention's pin registration system comprises a series of protrusions which are featured on at least two of the four corners of the top of the screen platform on which the screen frame rests. The screen frame features depressions or divots at locations on its underside, designed to mate with the protrusions on the screen platforms. Thus, the platform will lay in the same position relative to each and every screen frame each time a different screen frame is placed on the platform. In this manner, the pin registration system ensures that all passes of the squeegee are made over an accurately placed screen frame.
The device further comprises a mechanism that controls the vertical motion of the squeegee and the pressure and angle with which the squeegee is pressed onto the screen. Specifically, a cross beam is elevated above the screen platform and serves to mount the device's actuating components. The actuating components serve to mount the squeegee and regulate the pressure and angle that is applied to the screen as the squeegee passes over the screen. In one embodiment of the invention, the invention also features a gauge, which allows the user to monitor and regulate the pressure selected. The cross beam is mounted on a set of columns above the platform. The columns articulate along rails to pass the squeegee over the platform.
The actuating components are configured such that the pressure and angle exerted by the squeegee is monitored and kept consistent for each pass of the squeegee. In this way, any user that operates the device at any time, can produce consistent silk screened articles. Also, different passes of the squeegee will ink the article with a consistent amount of ink. Moreover, by matching the pressure exerted by the device to the pressure exerted by a mass production silk screening machine, or a pressure to obtain corresponding results, the device can produce sample articles that will more accurately represent the mass produced articles that are to be produced. In one embodiment of the invention, the mount that holds the squeegee is controlled by a pneumatic device.
The invention may be practiced using hydraulic or pneumatic actuating mechanisms.
The motion of the squeegee along the rails can be controlled by either the manual operation of the operator or by an automated mechanism using electromechanical, pneumatic, hydraulic, or any other such mechanisms known in the art.
In those embodiments using an automated mechanism to effectuate the motion of the squeegee along the rails, the vertical motion of the squeegee with respect to the rails can be controlled by the device such that, when the pass of the squeegee is completed, the squeegee is automatically raised. The automated mechanism used can be any of the mechanisms known in the art, including pneumatic devices, hydraulic devices, electro-pneumatic, electro-hydraulic, worm gears, belt drives, chain drives, or any of the numerous other drive mechanisms known within the art.
It should be noted that, in the interests of clarity, numerous details for the functionality of the controlled pressure silk screening device and variations on the configuration of the device are not included in this disclosure. Nevertheless, these details are well known within the art and the variations remain within the contemplation of this invention.
In summary, the invention teaches a silk screening device that allows consistent production of silk screened articles through the use of a controlled pressure squeegee and a pin lock registration system for the placement of the screen frame.
In the following detailed description of various embodiments of the invention, numerous specific details are set forth in order to provide a thorough understanding of various aspects of one or more embodiments of the invention. However, one or more embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, procedures, and/or components have not been described in detail so as not to unnecessarily obscure aspects of embodiments of the invention.
In the following description, certain terminology is used to describe certain features of one or more embodiments of the invention. For instance, “pneumatic mechanism” or “controlled pressure” refers to pneumatic, hydraulic, electromechanical, or any other such devices known in the art, including those that use compressed gas or liquids to apply regulated pressure; “silk screen device” refers to any of the single or multi-colored traveling-inker stenciling devices known in the art; and “article” refers to any garment, paper, fabric, or other such device commonly printed upon using silk screening devices.
