A hickey, a screen-ejection defect, appears as a small dot or line on a printed substrate. The most common cause of hickeys is the presence of a foreign particle, such as dust or lint, that has lodged in the screen mesh of a screen printing press. When the screen is wiped with a squeegee during printing, this pushes the foreign particle through the mesh, creating an imperfection. The ink from the stencil passes over this hole onto the substrate when it is moved by the squeegee’s continued movement across the surface, creating what’s known as a hickey.
Hickeys can also be caused by static electricity, which causes the ink to become electrically charged and stick to your substrate in random areas. In some cases, they may be due to improper screen tension causing sagging, so you’ll find tiny voids within your stencil where bleed might occur.
Most often seen as cosmetic defects rather than functional issues, hickeys have an occasional practical impact – for instance if one falls within the barcode area and makes reading code impossible.
A hickey (a screen ejector pin/screen lock pin) removes the device’s mesh from its frame after the image has been printed onto the material. The pin/slot mechanism works by inserting hickey into purpose-made holes around the frame’s border and then pulling out – this causes the frame part called ‘screen’ to eject itself (i.e., pop out)– ideal for fast changing between print runs.
It is typically made from metal or plastic and available in various sizes/shapes, including round/oval/square, plus smooth/textured varieties. Some come with a notch/groove along one side, which helps grab hold of the mesh + stops it slipping from the grip while removing.
As essential tools for businesses regularly involved in screen printing, they are inexpensive purchases.