Thermal print heads are typically used to print images to substrates by heating portions of a thermal print ribbon having a transferable print consumable, such as colored dye, black resin, or other print consumable. The thermal print head includes a row of print elements. Each print element is configured to heat a pixel-sized portion of the print ribbon to transfer a corresponding image pixel of the print consumable to the substrate.
Embodiments of the present disclosure are directed to an asymmetric thermal print head, a method of printing an image on a substrate using the asymmetric thermal print head, and a credential production device that includes the asymmetric thermal print head. Some embodiments of the asymmetric thermal print head include a print head body and a plurality of print elements supported on the print head body. The print elements are aligned along a first axis. Each print element includes a heater portion having a burn width measured along the first axis corresponding to a first print resolution, and a burn length measured along a second axis, which is perpendicular to the first axis, corresponding to a second print resolution. The second print resolution is higher than the first print resolution. One or more control circuits are configured to individually activate the print elements.
In some embodiments of the method, an image line is printed on a surface of the substrate by printing a plurality of pixels using the asymmetric print head. Each of the pixels has a pixel width measured along a first axis that is aligned with the image line, and a pixel length measured along a second axis that is perpendicular to the first axis. The print head is shifted relative to the substrate along the second axis a distance corresponding to the pixel length. These printing and shifting steps are repeated a limited number of times to complete the printing of the image on the substrate.
Some embodiments of the credential production device include a print ribbon, and the asymmetric thermal print head configured to print an image to a surface of a substrate using the print ribbon. The asymmetric thermal print head includes a print head body and a plurality of print elements supported on the print head body. The print elements are aligned along a first axis. Each print element includes a heater portion having a burn width measured along the first axis corresponding to a first print resolution, and a burn length measured along a second axis, which is perpendicular to the first axis, corresponding to a second print resolution. The second print resolution is higher than the first print resolution. One or more control circuits are configured to individually activate the print elements.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the Background.
The print head 100 also includes one or more control circuits 110, each of which is configured to selectively activate print elements 102 within a group. This activation of a print element 102 involves delivering a current to the heater portion 106 of the print element 102 through corresponding electrodes 112, in accordance with conventional thermal print head operations. The resistive heating element of the heater portions 106 generates heat in response to the current. A protective glaze 113 may be applied over the heater portions 106 to protect the heater portions 106, and provide a smooth contact surface, as shown in
The heat generated by the heater portions 106 of an activated print element 102 may be used to print an image to a substrate, as generally illustrated in
The print ribbon 116 generally includes a print consumable attached to a carrier layer that may be transferred to the surface 118 of the substrate 114 from the carrier layer using the print head 100 during a print operation. The print consumable may take on any suitable form, such as a colored dye (e.g., yellow, cyan, or magenta), a black resin, or other print consumable, in accordance with conventional thermal print ribbons 116.
An image 120 may be printed to the surface 118 of the substrate 114 through the printing of several image lines 122 using the print head 100 and the print ribbon 116, as shown in
The heater portions 106 of the thermal print head 100 each have a burn width 130 measured along the burn axis 108, and a burn length 132 measured along the axis 128 that is perpendicular to the burn axis 108, as shown in
Conventional thermal print heads utilize print elements 102 having symmetric heater portions. That is, the burn width of the heater portions of conventional print heads substantially match their burn length. As a result, conventional symmetric thermal print heads are configured to produce symmetric pixels 124′ each having a width 134′ that substantially matches its length 136′, as generally shown in
The asymmetric thermal print head 100 of the present disclosure includes print elements 102 each having a burn width 130 that is different from the burn length 132. Thus, the print elements 102 of the asymmetric thermal print head 100 are configured to print asymmetric pixels 124, an example of which is illustrated in the simplified top view of
Due to the dimensions of the burn portions 106, the print head 100 may perform a printing operation having a higher resolution along the axis 128 than along the burn axis 108, as shown in
In some embodiments, the print resolution of the asymmetric thermal print head 100 along the axis 128 is approximately double (e.g., ±10%) the print resolution along the burn axis 108, as generally shown in
It should be noted that the thermal print head 100 provides a higher printing resolution along the axis 128 while using the same number of control circuits 110 required to provide the lower print resolution along the burn axis 108. This provides advantages over symmetric print heads that are configured to print at the higher resolution. For example, the asymmetric print head 100 requires fewer control circuits 110 than are required by the symmetric version, while providing the higher print resolution along the axis 128. This allows the asymmetric print head 100 to be produced at a significantly lower cost than the symmetric version.
Additional embodiments include methods of printing an image to a substrate using the asymmetric thermal print head 100, which is formed in accordance with one or more embodiments of the present disclosure. In the method, an image line 122 is printed on a surface 118 of a substrate 114 by printing a plurality of pixels 124, as discussed above and illustrated in
Some embodiments are directed to credential production devices that include the asymmetric thermal print head 100 formed in accordance with one or more embodiments of the present disclosure.
The credential production device 150A is generally configured to directly print an image to a surface 152 of a substrate 154 using the asymmetric thermal print head 100 and a thermal print ribbon 116, as shown in
The substrate 154 is supported by a platen roller 156 or other suitable support, and the print ribbon 116, which may be supported between a supply spool 158 and a take-up spool 160, is positioned between the surface 152 and the print head 100, as shown in
The credential production device 150B is generally configured to perform a reverse-image transfer printing process to print an image to the surface 152 of a substrate 154, such as a credential substrate, to form a final printed product. The print head 100 is configured to print the image to a transfer ribbon 162, which may be supported between a supply spool 164 and a take-up spool 166. The transfer ribbon 162 may be formed in accordance with conventional transfer ribbons and include a fracturable thin film laminate or overlaminate patches that may be transferred to a substrate 154. The print head 100 prints the image to the transfer ribbon 162, which is supported by a platen roller 168, by thermally transferring a print consumable from the thermal print ribbon 116 to a transferrable surface 170 of the transfer ribbon 162, such as shown in
The credential production devices 150A and 150B may each include additional components to facilitate the production of a credential product. For example, the devices 150A and 150B may include a controller 176 that is configured to control components of the devices 150A and 150B to perform one or more functions described herein, such as printing operations using the asymmetric thermal print head 100, for example. The controller 176 may represent one or more processors and memory (e.g., local or remote memory). The one or more processors are configured to control operations of the devices 150A or 150B in response to the execution of instructions contained in the memory.
In some embodiments, the devices 150A and 150B include a transport mechanism 178 configured to feed individual substrates 154 along a processing path 180. In some embodiments, the transport mechanism includes motorized feed rollers and/or pinch roller pairs 182 for driving the individual substrates 154 along the processing path 180 to the print head 100 (
In some embodiments, the devices 150A and 150B include a substrate supply 184 containing a plurality of the substrates 154. The transport mechanism 178 may be configured to feed the individual substrates 154 from the supply 184 along the processing path 180, as shown in
In some embodiments, the devices 150A and 150B include a head lift mechanism 186 that is configured to move the asymmetric thermal print head 100 either relative to the processing path 180 or platen roller 156 (
The credential production devices 150A and 150B may also include other processing devices 190 that are configured to perform one or more processes on the substrate 154. These processing devices may include, for example, a substrate rotator 190A configured to rotate the substrate 154, a laminating unit 190B for the device 150A configured to apply an overlaminate to the surface 152 of the substrate 154, a data encoder 190C configured to read and/or write data to a memory chip of the substrate 152, a magnetic stripe reader and/or writer 190D configured to read and/or write data to a magnetic stripe of the substrate 154, and/or other suitable substrate processing devices.
Although the embodiments of the present disclosure have been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the present disclosure.
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Number | Date | Country | |
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20190202213 A1 | Jul 2019 | US |