Patent Application
20130328953
This disclosure relates to printers and, more particularly, to printers configured to print on large surfaces.
Large planar surfaces, such as windows, doors, walls, cars, semis, vans, and buses, are often used by businesses as an advertisement or decorative medium. These large planar surfaces may contain images of decorations, current prices, products, company names, phone numbers, and other information relevant to customers. Some of this information is prone to frequent changes. Thus, many of the advertisements and decorations are temporary, intended for a short term sale or event, or as a seasonal decoration.
Images on large planar surfaces may be hand-drawn, meaning that a person directly applies paint or other colorant to the surface. However, hand-drawing an image on a large surface can be time consuming. The quality of the image is limited by the artistic abilities of the person drawing the image, and obtaining a skilled artist to draw the image is often expensive, and, for a temporary image, impractical. Furthermore, if the image becomes damaged or needs to be changed, the same artist may be needed to repair the image. If the same artist is unavailable, the image may be of poor quality after the image is repaired or modified.
Images on large planar surfaces may also be printed by a printer. Because the surface is too large and rigid to be fed through a printer, the image is first printed on a sheet of vinyl or plastic by a conventional inkjet or xerographic printing process. The sheet is then attached to the vehicle, window, or other large planar surface with adhesives for display. Application of the sheet, however, can be labor intensive to ensure that no defects are generated in the image placement. Furthermore, modifications or repairs of the printed image are not possible without replacing the entire image. Therefore improved image generation on large planar surfaces is desired.
A portable printer has been developed that enables printing of surfaces in diverse environments. The printer includes a frame, a printhead operatively connected to the frame and configured to eject ink onto a printing surface, the printhead being movable in a first direction and a second direction, the first and second directions being substantially parallel to the printing surface, and an attachment mechanism configured to selectively couple the frame to the printing surface to position the printhead a predetermined distance from the printing surface to enable the printhead to eject ink onto the printing surface.
A method of using the printer enables printing of surfaces in diverse environments. The method includes attaching a frame to a printing surface, the frame being operatively connected to a printhead, moving the printhead within the frame in a first direction that is substantially parallel to the printing surface, moving the printhead within the frame in a second direction that is substantially parallel to the printing surface and perpendicular to the first direction, and operating the printhead to eject ink on the printing surface to form an image as the printhead moves in the first and second directions.
For a general understanding of the environment for the apparatus and method disclosed herein as well as the details for the apparatus and method, reference is made to the drawings. In the drawings, like reference numerals have been used throughout to designate like elements.
As used herein, the term “ink” refers to a colorant that is liquid when applied to an image receiving surface. For example, ink can be aqueous ink, ink emulsions, solvent based inks, gel inks, UV cured inks, sugar or vegetable based inks, and phase change inks. The ink can also be permanent or the ink can be temporary, intended to be washed off. “Phase change ink” refers to inks that are in a solid or gelatinous state at room temperature and that change to a liquid state when heated to an operating temperature for application or ejection onto an image receiving surface. The phase change inks return to a solid or gelatinous state when cooled on the print media after the printing process.
The electronics housing 150 is mounted on the bottom of the frame 110 in the embodiment of
The printhead assembly 170 includes a printhead face 174 in which a plurality of inkjets are arranged and configured to eject ink onto the surface to which the imaging device 100 is attached. The inkjets in the printhead assembly 170 can be piezoelectric inkjets that are configured to eject ink drops in response to a mechanical force generated by a piezoelectric transducer positioned in each inkjet. The printhead assembly 170 can include inkjets configured to eject a single color of ink, or the printhead assembly 170 can include multiple arrays of inkjets configured to eject different colors of ink, such as black, cyan, magenta, and yellow, to enable the printhead 170 to eject ink to form a color image. The printhead assembly 170 includes at least one ink storage and delivery system for each color of inkjet in the printhead face 174 to supply ink to the inkjets. The printhead assembly 170 can also include one or more heaters to enable the printhead assembly 170 to melt phase change ink or heat liquid ink to a predetermined temperature for delivery to the inkjets and ejection to the printing surface.
The actuators in the electronics housing 150 are configured to move the printhead assembly 170 in the horizontal and vertical directions within the horizontal 114 and vertical 118 rails. In one embodiment, friction drive mechanisms are used to move the printhead within the rails 114, 118, although in other embodiments, gears, belts, pulleys, or any suitable combination of gears, belts, pulleys, friction drive or other known motion and drive elements are configured to move the printhead assembly 170. The printhead assembly 170 can be manually adjusted in the direction normal to the printing surface to position the printhead face 174 at a predetermined distance from the printing surface that is suitable for printing on the surface. Alternatively, as described below, a drive system can be utilized to move in the normal or “Z” axis to establish printer distance to the image receiving surface. The inkjets in the printhead face 174 eject ink onto the printing surface as the printhead assembly 170 moves within the rails to form an image on the printing surface. The imaging device 100 can be further configured to eject two or more layers of solid ink on a surface to generate a three dimensional image, the depth of which can be facilitated by one or more Z-axis adjustments as the image height increases. Once the image is completed, the suction cups 160 are disengaged from the printing surface and the portable imaging device 100 can be stored, used at another location, or adjusted in position to extend the initial image, enabling the overall printed image size to be larger than the printing range of the horizontal and vertical travel.
Four suction cups 260 are fixedly mounted on the frame 210 and configured to attach the portable imaging device 200 to a printing surface 300. The suction cups 260 each include a clamp lever 264 configured to force air out of the suction cup 260 when the suction cup 260 is pressed against the printing surface 300, generating a vacuum inside the suction cup to retain the frame 210 on the surface 300. The portable imaging device illustrated has four suction cups, but there can be more or less suction cups depending on the size and weight of the portable imaging device. A smaller size printer can be configured with two or three suction cups for example, while a large or heavy device can include five or more suction cups. In other practical embodiments the suction cups can be pneumatically operated with an on-board pump or external vacuum source or the suction cups can be of a manual lever actuated configuration. Alternatively, the suction cups can be replaced with clamps or an elastomeric “bumper” configured to attach to or be held against the surface of an object to be printed by an external device, such as a fork lift.
The electronics housing 250 is mounted on the bottom of the frame 210 in the illustrated embodiment. In other embodiments, however, the electronics housing is located on a side of, on top of, or within the frame. The electronics housing 250 includes electronics components that operate the printer, including a controller and memory. The controller and other electronics are operatively connected to the printhead assembly 270 by wires and cables that can be supported by the horizontal 214, vertical 218, and normal 222 rails, and the frame 210. The frame and support rails can be attached to or formed as part of panels to partially or completely enclose the portable imaging device to increase rigidity of the frame, protect the components within, and reduce risk of interference with the printing and potential safety hazards that may be associated with such printing.
The printhead assembly 270 includes a plurality of inkjet ejectors located in a face of the printhead assembly 270 that are configured to eject ink onto the printing surface 300. The inkjets in the printhead face 274 eject ink onto the printing surface as the printhead assembly 270 moves within the frame 210 to form an image on the printing surface 300. The inkjets in the printhead can be piezoelectric inkjets that are configured to eject ink drops in response to a mechanical force generated by a piezoelectric transducer positioned in each inkjet. The printhead assembly 270 can include inkjets configured to eject a single color of ink, or the printhead assembly 270 can include multiple arrays of inkjets configured to eject different colors of ink, such as black, cyan, magenta, and yellow, to enable imaging device 200 to form a color image on the printing surface 300. The printhead assembly 270 includes at least one ink storage and delivery system for each color of inkjet in the printhead face to supply ink to the inkjets. The printhead assembly 270 can also include one or more heaters to enable the printhead assembly 270 to melt phase change ink or heat liquid ink to a predetermined temperature for delivery to the inkjets and ejection to the printing surface 300.
An optical sensor 280 is configured to generate digital image data corresponding to light reflected from the planar surface. The optical sensor can include an illumination source that directs light towards the surface and receives reflected light. The optical sensors can generate and detect light within and/or outside the visible light wavelength range. The digital image data generated by sensor 280 is delivered to a controller in the electronics housing 250. The controller is configured with programmed instructions stored in a memory operatively connected to the controller to process the image data to identify characteristics of the image, for example, edges and bounded areas or regions in the image on the planar surface. The controller then generates signals to operate actuators to move the printhead assembly 270 to a particular location over the surface 300 and also generates driving signals to operate inkjets in the printhead assembly 270 for the ejection of ink on the surface 300. In one embodiment the optical sensor is mounted on the printhead assembly 270, although in other embodiments the sensor is fixed to the frame or configured to move within the frame independent of the printhead assembly. Processing of the image data generated by the sensor 280 enables the portable imaging device 200 to assess the quality of the image as the image is printed and/or to print an image adjacent to an image detected on the printing surface 300 to extend, repair, and/or modify the detected image.
The portable printer can be oriented essentially horizontal or vertical for many images, such as descriptive text and pricing information. To facilitate placement of the printer on a surface, the imaging device 200 includes a level indicator 290. In the illustrated embodiment, the level indicator 290 is a bubble type level read by the user to position the imaging device. In other practical embodiments the level indicator can be an electronic level, for example an accelerometer, which generates an electronic signal that is delivered to the controller. The controller can then provide visual or audible signals to the user through a display or speaker indicating which end to drop or elevate to establish a level condition, or the controller can be configured to adjust the movement of the printhead and the operation of the inkjet ejectors in the printhead with reference to the alignment of the imaging device.
The printhead assembly 270 is mounted on the horizontal rails 214 and configured to move in the horizontal, vertical, and normal directions within the horizontal 214, vertical 218, and normal rails 222 by actuators 230, 234, 238, respectively. The normal direction refers to a direction that is orthogonal to both the horizontal and vertical directions. The actuators 230, 234, 238 each include a friction drive mechanism that includes a plurality of rotating wheels configured to engage the corresponding rails 214, 218, 222 under compression. The friction drive wheels can be spring loaded against the rails to establish friction and they can be formed of an elastomer material. The actuator rotates the wheel to move the rails and printhead assembly in the desired direction. Vertical drive actuator 234 is mounted on the normal rails 222 and configured to move the normal rails 222, horizontal rails 214, and printhead assembly 270 vertically within the frame 210 by driving wheels in the vertical rails 218. The normal drive actuator 238 is mounted on the horizontal rails 214 and configured to move the printhead assembly 270 in the normal direction by moving a wheel within the normal rails 222. The normal drive actuator 238 is configured to position the printhead assembly 270 at a predetermined distance from a printing surface 300 to enable inkjets in the printhead to eject ink onto the printing surface 300. The vertical drive actuator 238 enables the printhead to be positioned at the predetermined distance to adjust for ink build-up on the surface in three dimensional printing and for printing on a moderately non-planar surface, such as a vehicle windshield. The horizontal drive actuator 230 is mounted on the printhead assembly 270 and is configured to move the printhead assembly 270 horizontally within the frame 210 by turning one or more wheels compressed in the horizontal rails 214.
The controller 404 receives image data from image data memory 412 corresponding to an image to be printed onto a printing surface (block 504). The image data can be stored in memory 408 or another memory in the imaging device. The controller 404 operates the actuators 230, 234, 238 to move the printhead assembly 270 to an initial location (block 508). The controller operates the inkjets in the printhead to eject ink onto the printing surface corresponding to the image data received from the memory 412 (block 524) to form the image on the printing surface. The controller 404 then determines if additional image data 412 are ready for processing (block 528). If additional image data 412 are read to process, the controller operates the actuators 230, 234, 238 to move the printhead assembly 270 to a next location (block 532) and the process continues at block 524. If no more image data are ready, then the process 500 terminates (block 536).
For the printing of some images, such as descriptive text and pricing information, the portable printer needs to be essentially horizontal. To facilitate placement of the printer on a surface, a level indicator can be incorporated in the device. The level indicator could be a simple bubble level or it can be a electronic level that provides visual or audible signals to identify the end that requires dropping or elevation to establish a level condition. Repairing or extending an image on an object requires alignment with the original image before printing begins. This alignment can be achieved even if the printer is offset or skewed by optically imaging and analyzing a portion of the image present on the surface and then electronically adjusting the orientation of the image to be printed on the surface. A small display panel can be incorporated in the device by, for example, fixing the display to the electronics module, to facilitate leveling of the device and/or providing other operation information, such as ink volume remaining or of a need to replenish the ink supply. The portable printer can be configured to require a power cord connection to an electrical outlet or the electrical power source can be incorporated in the device by including an onboard battery or an external battery connected to the device via an electrical cable. Suction cups may be pneumatically operated with an onboard pump or external vacuum source or the cups can be configured with a manual lever to produce a vacuum.
It will be appreciated that variants of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems, applications or methods. Various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.
