Abstract:
A thermal transfer print head is disclosed. The print head includes a housing configured and dimensioned to be installable within the printer, a plurality of resistive heating elements positioned on an external surface of the housing and in thermal contact with a printable media, the resistive heating elements receive electrical energy from the printer and have adjustable thermal output, and a print head memory positioned within the housing and accessible by the thermal printer, the print head memory including a first and second memory regions, the first memory region configured to store a printing profile pertaining to operating parameters of the resistive heating elements and the second memory configured to store usage data pertaining to operation of the print head.

Description:
BACKGROUND  
       [0001]     1. Field of the Disclosure  
         [0002]     The present disclosure relates to thermal transfer printing, more specifically, to a system and method for print head profiling in a thermal transfer printer and storing usage data pertaining to the print head therein.  
         [0003]     2. Description of the Related Art  
         [0004]     Currently, there are a variety of printing techniques to transfer ink or toner to a sheet of paper, such as liquid and solid ink printing, toner laser printing, dye-sublimation printing and thermal transfer printing. In the case of thermal printing, a thermal print head provides thermal energy to specific locations of thermal-reactive printing media such as a thermal transfer ribbon. Generally, a thermal print head has a plurality of independently controllable resistive heating elements, when activated, heat a transfer ribbon and transfer thermally reactive inks or dyes from the ribbon to the paper. During this process, the heating elements cause the ink in discrete regions of the ribbon to sublimate into a gaseous state for a brief period. The amount of ink transferred to the paper, and hence, the ink saturation or tone depends on the temperature of the heating elements.  
         [0005]     Print heads are designed for use in specific printer models and are generally not interchangeable with print heads from other printers. This lack of interchangeability is due to printer design and operating parameters, which allow for print heads to be specifically tailored to a particular printer. Thus, all individual print heads of a particular model are designed to reliably and repeatedly produce equivalent print output when installed in the corresponding printer. However, imperfections during manufacture actually produce print heads that do not have identical characteristics and as a result have varying thermal responses. More specifically, the resistive heating elements produce varying amount of heat due to varying resistance. Thus, the individual print heads produce print output quality that is not exactly the same and only falls within an acceptable certain range.  
         [0006]     To minimize the discrepancies exhibited by print heads, it is possible to tailor the thermal response of each print head to the printer to produce consistent high quality prints. This requires characterizing a print head and providing an individual profile tailored for the print head. This is beyond the expertise level of most end users. In addition, it requires a significant amount of time to create such a profile. Therefore, there is a need for a system which would provide a built-in profile of the characteristics of the individual print head allowing for a printer to compensate for the variations and provide a more uniform output.  
       SUMMARY OF THE INVENTION  
       [0007]     System and method for thermal transfer print head profiling are disclosed. The system includes a print head configured for use in a thermal transfer printer, the print head having resistive heating elements for sublimating ink deposited on thermal transfer ribbon. In addition, the print head includes memory for storing a printing profile and usage data pertaining to the print head. The printing profile includes resistance values for the heating elements as well as other information concerning printing which is used by the printer to adjust the current passing through the print head to control printing quality. The print head also saves the usage data within the memory for later retrieval and analysis of the problems causing inoperability of the print head.  
         [0008]     In one embodiment of the present disclosure a thermal transfer print head for use in a thermal transfer printer is disclosed. The print head includes a housing configured and dimensioned to be installable within the printer, a plurality of resistive heating elements positioned on an external surface of the housing and in thermal contact with a printable media, the resistive heating elements receive electrical energy from the printer and have adjustable thermal output, and a print head memory positioned within the housing and accessible by the thermal printer, the print head profile memory including a first and second memory regions, the first memory region configured to store a printing profile pertaining to operating parameters of the resistive heating elements and the second memory configured to store usage data pertaining to operation of the print head.  
         [0009]     In another embodiment of the present disclosure a thermal transfer printing system having printing profile and usage data is disclosed. The printing system includes a thermal transfer printer having a control assembly and a print head installable in the thermal printer. The print head includes a housing configured and dimensioned to be installable within the printer, a plurality of resistive heating elements positioned on an external surface of the housing and in thermal contact with a printable media, the resistive heating elements receive electrical energy from the printer and have adjustable thermal output, and a print head memory positioned within the housing and accessible by the thermal printer, the print head profile memory including a first and second memory regions, the first memory region configured to store a printing profile pertaining to operating parameters of the resistive heating elements and the second memory configured to store usage data pertaining to operation of the print head.  
         [0010]     In a further embodiment of the present disclosure, a method for improving output quality of a thermal transfer printer and tracking print head usage is disclosed. The method includes the steps of providing a print head having a memory including a first and second memory regions and a plurality of resistive heating elements positioned on an external surface thereof and in thermal contact with a print media, the resistive heating elements having adjustable thermal output, characterizing operating parameters of the resistive heating elements, collecting a printing profile pertaining to the operating parameters of the resistive heating elements and storing the printing profile in the first memory region, collecting usage data pertaining to operation of the print head and storing the usage data in the second memory region, and adjusting the thermal output of the resistive heating elements based on the printing profile.  
         [0011]     According to another embodiment of the present disclosure, a thermal transfer print head for use in a thermal transfer printer is disclosed. The print head includes a housing configured and dimensioned to be installable within the printer, a plurality of resistive heating elements positioned on an external surface of the housing and in thermal contact with a printable media, the resistive heating elements receive electrical energy from the printer and have adjustable thermal output, and a print head memory positioned within the housing and accessible by the thermal printer, the print head memory including a first memory region, the first memory region configured to store a printing profile pertaining to operating parameters of the resistive heating elements and identification data identifying the print head as authorized for use in the printer.  
         [0012]     According to a final embodiment of the present disclosure, a thermal transfer printing system having printing profile and identification data is disclosed. The printing system includes a thermal transfer printer having a control assembly and a print head installable in the thermal printer. The print head includes a housing configured and dimensioned to be installable within the printer, a plurality of resistive heating elements positioned on an external surface of the housing and in thermal contact with a printable media, the resistive heating elements receive electrical energy from the printer and have adjustable thermal output, and a print head memory positioned within the housing and accessible by the thermal printer, the print head memory including a first memory region, the first memory region configured to store a printing profile pertaining to operating parameters of the resistive heating elements and identification data identifying the print head as authorized for use in the printer. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     The above and other aspects, features, and advantages of the present disclosure will become more apparent in light of the following detailed description when taken in conjunction with the accompanying drawings in which:  
         [0014]      FIG. 1  is a block diagram of a thermal printer in accordance with the present disclosure;  
         [0015]      FIG. 2  is a block diagram of software components of the thermal printer of  FIG. 1  in accordance with the present disclosure;  
         [0016]      FIG. 3  is a schematic of a thermal print head in accordance with the present disclosure; and  
         [0017]      FIG. 4  is a flowchart of a method for improving output quality of a thermal printer in accordance with the present disclosure. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0018]     Preferred embodiments of the present disclosure will be described herein below with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail.  
         [0019]     The present disclosure provides for a system and method of profiling a thermal print head. The print head is configured to electrically connect to a thermal transfer printer and heat dyes deposited on a thermal transfer ribbon to transfer them to print media using resistive heating elements. The print head includes memory configured to store a printing profile and usage data. The printing profile includes information pertaining to the resistance of the heating elements which are used by the printer to adjust its current to achieve better printing quality. In addition, the usage data is extracted and analyzed to determine the cause of any problems and general usage statistics.  
         [0020]     It should be appreciated by those skilled in the art that the various embodiments according to the present disclosure may be adapted for use in a plurality of printing systems and that the illustrated embodiment involving a thermal printing system is used for illustrative purposes.  
         [0021]     Referring to  FIG. 1 , a thermal printer  12  is shown including a controller assembly  204  having a processor  206 , a random access memory (RAM)  391 , a read only memory (ROM)  392  and input/output (I/O) interface(s) such as a keypad  393 , a and display device  395 . Furthermore, the printer  12  may also include a networking device  397  which provides wired or wireless connectivity to a network. In addition, various other peripheral devices may be connected to the thermal printer  12  by various interfaces and bus structures, such as a parallel port, serial port or universal serial bus (USB). A system bus  396  may be included which couples the various components and may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of different bus architectures.  
         [0022]     The printer  12  may also be configured to include an operating software and micro instruction code. The various processes and functions described herein may either be part of the micro instruction code, firmware, or part of the application program (or a combination thereof) which is executed via the operating system. In addition, the thermal printer  12  may be designed to include software for displaying user input screens and recording user responses as discussed in more detail below.  
         [0023]     It is to be further understood that because some of the constituent system components and method steps depicted in the accompanying figures may be implemented in software, the actual connections between the system components (or the process steps) may differ depending upon the manner in which the present disclosure is programmed. Given the teachings of the present disclosure provided herein, one of ordinary skill in the related art will be able to contemplate these and similar implementations or configurations of the present disclosure.  
         [0024]     The processor  206  is primarily used to perform operational tasks required for printing and controlling a print head  102 , a ribbon system  28 , and a media system  20 , consisting of guide ramps, feed rollers, sensors, motors, etc. The media system  20  transports printer media (e.g., sheets of paper, labels, cards, etc.) from an input port  210  through a printing area  208  where the ribbon system  28  passes a thermal transfer ribbon (not shown) between the print head  102  and the media. The dyes deposited on the ribbon are heated by the print head  102  and are sublimated on the media to generate a print output, according to the output commands and data received from the control assembly  204 . The printed media is thereafter transported by the media system  20  through an output port  210 .  
         [0025]      FIG. 2  shows a print engine  13  for printing content. The printer engine  13  may be a software module stored within the controller assembly  204 . The printer engine  13  receives data for output (e.g., images and/or text, etc.) from a computer  10  through an interface  14  configured to accept and process incoming data and/or commands. The printer engine  13  also includes a print processor  16  for controlling the operation of the printer engine  13 . The print processor  16  interfaces with a media controller  18 , print head controller  22 , and ribbon controller  26 . The media controller  18  controls the media system  20  and its components which may include guide ramps, feed rollers, sensors, motors, etc. Furthermore, the media controller  18  monitors the progress of the media through the printer  12 . The ribbon controller  16  controls the ribbon system  28  which passes the thermal transfer ribbon between the print media and the print head  102 . The print processor  16  controls the print head  102  through the print head controller  18  by adjusting the heat generated the print head  102 . In addition, the print head controller  18  communicates with the print head  102  to create and/or read printing profile and generate and store usage data. These functions will be discussed in more detail in conjunction with  FIG. 4 .  
         [0026]      FIG. 3  shows a schematic of the print head  102  which includes a plurality of resistive heating elements  104 , a print head memory  106  having a first memory region  108  and a second memory region  110 , and a connector  112  for electrical communication with the controller assembly  204 .  
         [0027]     The heating elements  103  are activated by passing electrical energy therethrough based on the commands from the control assembly  204 . During activation, the heating elements  103  heat the ribbon which causes the ink deposited therein to transfer to the printing media. The activation of the heating elements  103  and other operations of the print head  102  is controlled by the print head controller  22 .  
         [0028]     Preferably, the print head memory  106  is non-volatile and may be provided by a printed circuit board mounted along the print head  102 . Furthermore, those skilled in the art will understand that the print head memory  106  may include a plurality of memory regions and that the described-above first and second memory regions  106  and  108  are used to illustrate the two types of data stored therein (e.g., printing profile and usage data) as discussed in more detail below.  
         [0029]     The print head memory  106  stores a printing profile for the print head  102  in the first memory region  108 . The printing profile may include operating characteristics such as the print head manufacturer, the date of manufacture, the maximum and average resistance of the heating elements  103 , thermal constants at which the print head  102  dissipates heat and other operational parameters. The operational parameters may be customized with respect to a specific model of the print head  102  to allow for the electrical adjustment necessary for proper operation of the print head  102  with the printer  12 . This data facilitates in improving print quality since the printer  12  obtains the data from the print head  102  and adjusts its controls accordingly.  
         [0030]     More particularly, the printing profile includes resistance values of the heating elements  103  to allow the printer  12  to adjust the voltage passing through the printer head  102  to obtain consistent results of the ink deposited on the media. Furthermore, since the first memory region  108  is primarily used for providing data to the printer, preferably it is marked as read only memory. This provides greater safeguards against accidental or deliberate tampering with the printing profile.  
         [0031]     In addition, the print head memory  106  stores usage data pertaining to the operation of the print head  102  in the memory region  110 . The usage data may include average current passing through the heating elements  103 , printing load, printing commands, etc. This data may be valuable to the manufacturer of the print head  102  in analyzing the performance of the print head  102 . More specifically, it is useful in determining design and manufacture defects in faulty units which may be returned to the manufacturer after failing. Thereafter, the manufacture would extract the usage data to facilitate its fault recovery process. In addition, since the second memory region  10  is used for writing and extracting data (e.g., writing from the printer  12  to the print head  102  to obtain usage data and extracting from the print head  102  for analysis of usage data) preferably it is marked as read and write memory.  
         [0032]     It is also envisioned that print head memory  106  may be also configured to store identification data to identify itself as an approved print head (e.g., manufactured specifically to work with the printer  12  and having the printing profile for optimal performance with the printer  12 ). The printing profile for the print head  102  is only extracted once the identification data is processed by the printer  12 . Thereafter, the control assembly  204  accesses the print head memory  106  to retrieve the printing profile.  
         [0033]     This embodiment prevents unauthorized print heads from attempting to load unapproved and/or untested printing profiles. For instance, a third party manufacturer may attempt to duplicate a printing profile for an unauthorized print head to attempt to match the performance of a native print head  102 . Such third party profiling is undesirable since it may damage the printer  12 . Therefore, the identification data prevents the use of third party and/or unauthorized print heads from passing unauthorized printing profiles to the printer  12 . It is also envisioned that identification data may be used to prevent third party print heads from communicating with the control assembly  204 , thereby preventing their use in the printer  12 .  
         [0034]      FIG. 4  shows a method for improving output quality of the printer  12  using the print head memory  106 . In step  300 , a profile for the print head  102  is created including the parameters discussed above. The profile may be created during manufacture and is stored in the first memory region  108  in step  302 . In addition, the profile may be created by the printer  12  during initial use of the print head  102 . The printer  12  may include software within the control assembly  204  to measure the resistance of the heating elements  103  and then store those values as the printing profile in the first memory region  108 . In addition, the identification data is also embedded in the first memory region  108 .  
         [0035]     The profile and the identification data are encrypted in order to prevent unauthorized third parties from accessing the data pertaining to printing parameters of the print head  102 . Usually, such data is proprietary, hence, it is desirable to protect the data in order to discourage manufacture of third party print heads, the usage of which may result in poor quality printing. Encryption may be accomplished by using any of widely available encryption algorithms and methods or using specialized chips, such as CryptoMemory.  
         [0036]     In step  304 , the print head  102  is installed into the printer  12  and the connector  112  electrically connects the print head  102  to the control assembly  204 . The print head memory  106  is also accessed by the processor  206  which verifies that the print head  102  is authentic by retrieving the identification data in step  305 . If the print head  102  is not authentic, the printer  102  does not retrieve the printing profile and operates in a standard manner. Optionally, the printer  102  may not even operate with the unauthentic print head.  
         [0037]     If the identification data confirms that the print head  102  is authentic, the process proceeds to step  306 , where the control assembly  204  accesses the print head memory  106  to retrieve the printing profile from the first memory region  108  and to create a usage data file and store it in the second memory region  110 . Following the profile retrieval, in step  308 , the controller assembly  204  adjusts printing algorithms based on the printing profile, thus compensating for variations in resistive heating element response and improving printing quality.  
         [0038]     Once the printing profile is loaded by the control assembly  204 , the printer  12  is ready for printing. In step  310 , the printer  12  processes a print job, which involves receiving printing commands and data from the computer  10  through the interface  14  and processing them using the print processor  16 . The print processor  16  activates the corresponding components of the printer  12  as well as print head  102  based on the retrieved printing profile.  
         [0039]     Upon completion of each print job, in step  312 , the printer  12  compiles relevant usage information, such as date the print head was purchase and/or installed, number of pages printed, total coverage, coverage per page, number of times each resistive heating element has been activated and duration, thermal output of each resistive heating element, printer model and serial number, etc. The usage data is stored in the second memory region  120  in step  314 .  
         [0040]     In step  316 , it is determined if the print head  102  is operating properly. This may be done automatically and/or manually. The end user of the printer  12  may notice degradation in the print quality and thus discover that the print head  102  is faulty. In addition, the printer  12  may analyze the usage data to determine whether the print head  102  is performing below acceptable standards. If the print head  112  is performing properly, the process loops to step  306  where the printer  12  continues to process print jobs. If the print head  112  is faulty, the end user then removes the print head  102  and contacts the manufacturer for service and/or replacement. It is envisioned that the user may also return the print head  112  for regular scheduled maintenance (e.g., adjustment).  
         [0041]     In step  318 , the manufacturer, upon receiving the returned print head  102  retrieves the usage data from the second memory region  110 . The manufacturer  320  thereafter analyzes the usage data in step  320  to determine the cause of the malfunction. Such data may be used to identify the cause of error (e.g., improper operation, design and/or manufacture defect, etc.). This data may be also used by the manufacturer to design better print heads and alleviate any of the problems inherent in the prior designs. If the problem was caused by the end user, then the manufacturer may also discover such misuse and terminate any warranty or service coverage the print head may have had.  
         [0042]     The present disclosure provides a print head for a thermal transfer printer having a memory electrically connected to the printer during operation. The print head stores a printing profile having resistance information of heating elements and usage data pertaining to the printing activities performed by the print head. The printing profiles allows the printer to configure its current output to correspond to the resistance of the print head thereby to improve print quality, extend the operational life time of the print head, and improve the rate of printing. Moreover, the usage data stored within the print head provides invaluable data pertaining to the printing performance of the print head.  
         [0043]     The described embodiments of the present disclosure are intended to be illustrative rather than restrictive, and are not intended to represent every embodiment of the present disclosure. Various modifications and variations can be made without departing from the spirit or scope of the disclosure as set forth in the following claims both literally and in equivalents recognized in law.