Print head shutter

[0002] The present invention relates generally to shutters for print heads.

[0003] Many imaging devices used to print labels on objects, such as cartons, boxes, or the like employ a stationary inkjet print cartridge having a print head. Printing is accomplished by moving the object past the print head so that the print head deposits an image on the object by spraying ink through a number of nozzles in the print head onto the object. However, when the print head is not being used, many inks dry out, clogging the nozzles. For imaging devices, such as desktop printers, having movable print heads that move over a stationary printable medium during printing, the print cartridge and thus the print head is moved to a location where the print head is covered to prevent the ink from drying out and clogging the nozzles when the imaging device is not in use. However, by design stationary print heads cannot be moved to a location for covering the print head.

[0004] For the reasons stated above, and for other reasons stated below that will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for preventing inks from drying out and clogging the nozzles of the print heads of stationary print cartridges.

[0005] One embodiment of the present invention provides a shutter for a print head of a print cartridge. The shutter includes a cover movably attachable to the print cartridge. The cover is movable between a closed position to cover the print head and an open position to expose the print head. An arm is pivotally attachable to the print cartridge and is movably attached to the cover. A biasing device for biasing the cover in the closed position is attached to the arm and is attachable to the print cartridge.

[0006] In another embodiment, a print cartridge is provided. The print cartridge includes a body and a print head. A cover is movably attached to the body. The cover is movable within a plane substantially parallel to the print head between a closed position to cover the print head and an open position to expose the print head. An arm is pivotally attached to the body and is movably attached to the cover for moving the cover between the closed and open positions. A biasing device is attached to the arm and the body for biasing the cover in the closed position.

[0007] Further embodiments of the invention include methods and apparatus of varying scope.

[0008] FIG. 1 is a plan view of a print cartridge according to an embodiment of the present invention.

[0009] FIG. 2 is a plan view of the print cartridge of FIG. 1 illustrating exposure of a print head of the print cartridge according to another embodiment of the present invention.

[0010] FIG. 3 is an enlarged view of region 300 of FIG. 1.

[0011] FIG. 4 illustrates slidable attachment of a cover of the print cartridge of FIG. 1 according to another embodiment of the present invention.

[0012] In the following detailed description of the present embodiments, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that process, electrical or mechanical changes may be made without departing from the scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims and equivalents thereof.

[0013] FIG. 1 is a plan view of a print cartridge 100 according to an embodiment of the present invention. Print cartridge 100 includes a cartridge body 102 and a print head 104 or other marking device for depositing an image on a moving object, e.g. object 110. In one embodiment, print cartridge 100 is an inkjet cartridge and print head 104 includes a number of nozzles 105. Print cartridge 100 includes a shutter 106 or the like, for covering and uncovering print head 104. Shutter 106 is closed to cover print head 104 when print head 104 is not in use. This prevents ink of cartridge 100 from drying out and potentially clogging nozzles 105 of print head 104. A conveyer 108, such as a moving belt or the like, conveys object 110, e.g., a box, carton, or the like past print cartridge 100. Object 110 engages shutter 106 and moves shutter 106 from the closed position to an open position, as shown in FIG. 2, where print head 104 is exposed for printing on object 110 as object 110 movies past print cartridge 100. After object 110 moves out of engagement with shutter 106, shutter 106 automatically returns to the closed position.

[0014] More specifically, shutter 106 includes an arm 112 movably attached to a cover 116 of shutter 106 for moving cover 116 between the closed position shown in FIG. 1 and the open position shown in FIG. 2. In one embodiment, arm 112 is pivotally attached to cartridge body 102 by a pivot 114, such as a pin. Cover 116 is movable between the closed position to cover print head 104 and the open position to expose print head 104. In another embodiment, cover 116 is movable within a plane substantially parallel to a face plane 117 (shown in FIG. 2) of print head 104. Shutter 106 also includes a biasing device 118 connected between arm 112 and cartridge body 102 for automatically returning cover 116 to the closed position after object 110 moves out of engagement with arm 112. In one embodiment, biasing device is a spring, an elastic strip, or the like. Biasing device 118 biases cover 116 in a closed position, as shown in FIG. 1, so that cover 116 covers print head 104 when print head 104 is not in use to prevent the ink from drying out and potentially clogging nozzles 105 of print head 104.

[0015] FIG. 3 is an enlarged view of region 300 of FIG. 1 illustrating attachment of arm 112 to cover 116. In one embodiment, a pin 120 protrudes from an edge 122 of cover 116 and extends into a slot 124 of arm 112. Cover 116 is movably attached to a protrusion 126 of cartridge body 102, e.g., using rollers, slides or the like. Biasing device 118 exerts a force on arm 112 so that arm 112 bears against pin 120 of cover 116 to bias cover 116 in the closed position, as shown in FIGS. 1 and 3.

[0016] In one embodiment, a seal 125, e.g., an elastomer or the like, is disposed on an edge 127 of cover 116 substantially perpendicular to edge 122, as shown in FIG. 3. When cover 116 is in the closed position seal 125 abuts protrusion 129 of cartridge 100, reducing exposure of print head 104 to the environment outside cartridge 100, thus helping to prevent the ink of cartridge 100 from drying out and potentially clogging nozzles 105 of print head 104.

[0017] FIG. 4 illustrates slidable attachment of cover 116 to protrusion 126 according to another embodiment of the present invention. Rails 400 of cover 116 slide within grooves 410 disposed within protrusion 126. This maintains cover 116 substantially parallel to a face plane 117 of print head 104 as cover 116 slides between the closed and open positions. In one embodiment, rails 400 are integral with cover 116.

[0018] Object 110 engages arm 112 and pivots arm 112 about pivot 114 against the biasing force exerted on arm 112 by biasing device 118. As arm 112 pivots, arm 112 exerts a force on cover 116 via pin 120. This moves cover 116 in the direction of motion of object 110 to the open position, as shown in FIG. 2, thereby exposing print head 104. As arm 112 opens cover 116, pin 120 travels within slot 124 of arm 112 so that cover 116 moves substantially parallel to print head 104.

[0019] In one embodiment, pin 120 is located adjacent an end 134 of slot 124 when cover 116 is closed, as shown in FIG. 3. In another embodiment, when cover 116 is open, pin 120 is located adjacent an end 136 of slot 124 that is opposite end 132, as shown in FIG. 3. In some embodiments, an extension 140 extends angularly from an end 142 of arm 112 to form an angle 144 with respect to arm 112, as shown in FIG. 1. In one embodiment, angle 144 is such that extension 140 is substantially parallel with face plane 117 of print head 104 and abuts cover 116 when cover 116 is open, as shown in FIG. 2.

[0020] Object 110 moves over extension 140 as it moves past print cartridge 100. As object moves past print head 104, ink is sprayed through nozzles 105 of print head 104 onto object 110 to deposit an image on object 110. In one embodiment, a gap 146 separates print head 104 from object 110 during printing, as shown in FIG. 2, and the ink is sprayed across gap 146.

[0021] After object 110 moves past and out of engagement with extension 140, biasing device 118 returns arm 112 to the position shown in FIG. 1, thereby closing cover 116. Specifically, biasing device 118 pivots arm 112 about pivot 114, and arm 112 exerts a force on cover 116 via pin 120, causing cover 116 to move counter to the direction of motion of object 110 into the closed position. As arm 112 closes cover 116, pin 120 travels within slot 124 in a direction from end 136 to end 134 so that cover 116 moves substantially parallel to print head 104.

[0022] Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement that is calculated to achieve the same purpose may be substituted for the specific embodiments shown. Many adaptations of the invention will be apparent to those of ordinary skill in the art. Accordingly, this application is intended to cover any adaptations or variations of the invention. It is manifestly intended that this invention be limited only by the following claims and equivalents thereof.