Patent Application
20070030328
1. Field of the Invention
The present invention relates to an apparatus and a method for multichannel sequence transmission and control, and more particularly to a print control of data transmission for a thermal-wax transfer printer or a thermo-printer.
2. Description of the Prior Art
Due the popularization of digital image products and developments of products and inks relative to printing, users are easy to print by a general printer out a photograph whose quality is close to the developed photographs. The color printers available in the market are classified into colored ink jet printer, colored laser printer, and thermal-wax transfer printer. The paper printed by ink jet printer is easy muddied by water, and so the image printed in the paper is smudged. Furthermore, a printing speed of the ink jet printer is slower. The quality and speed of the laser printer are better than that of the ink jet printer, but the price of laser printer and the cost for printing is too high for general users. The printing speed of thermal-wax transfer printer is better, and the photograph has a good printed quality and a water-resistant coating. Moreover, the printed cost is cheaper, and so this has become the mainstream in the printer market.
The data-transmission and printing method of the conventional thermal-wax transfer printer will be described in the following. First, the contents desired to print, comprising words, pictures, are transmitted in line/row-based transmission method controlled by an external microcontroller, such as CPU or MCU, to a shift register into a printhead in sequence. Next, the line/row-based contents in the shift register are transmitted to latch register to store via a latch signal set by a control unit. Plural heating units corresponding to the latch register are activated by strobe signals generated by a strobe signal generator and then heat respective color dyes of the ribbon onto a surface of printed media, such as paper or photographic paper. Predetermined line/row content is printed through the colors dyes of ribbon, and then the printed paper is moved by a rotating axle to the next line and so the printing process of “one line” is completed. The printing process is performed repeatedly for printing content onto the surface of the printed media. However, as data-transmission and printing method described above, the complete data-transmission and control are directly controlled by the external microcontroller. Therefore, the data transmission, printing speed and quality are directly decided upon the ability of data process of the microcontroller.
In addition, a structure of the thermal-wax transfer printer mentioned above has a main key device of thermal-wax transfer printhead that employs plural heating units therein to heat a color ribbon for sublimating dyes and generating an image on a surface of the printed media. The heating unit is a thermal resistor, heats to rise temperature whiling the current being flowing therein and cools when the current stopped. Therefore, thermal-wax transfer printer is to perform a printing action with the characteristic of the thermal resistors mentioned above.
The ribbon applied in the thermal-wax transfer printer is a stable solid state at room temperature and is sublimated to vaporize when the temperature is higher than a threshold temperature, wherein the ribbon comprises a plurality of color regions arranged sequentially; each has different color dyes thereon. The amount of dyes transferred onto the printed media is based on a vaporized duration of the dyes, and the amount of dyes is higher and the gray level of color is deep. Hence, to achieve a preferred printing quality has to heat the ribbon over the threshold temperature for a space. Unfortunately, the heating unit has an upper temperature limit, and so the heating unit heats to rise temperature faster in the initial and may be broken when the temperature is over the upper temperature limit, as shown in
A main objective of the present invention is to provide an apparatus and a method for multichannel sequence transmission and control for a thermal-wax transfer printer or a thermo-printer.
Another main objective of the present invention is to provide an apparatus and a method for multichannel sequence transmission and control, in which a DMA generator is coupled to a bus interface and a data generator. Therefore, the data designated to print is directly transmitted via memory and it decreases the loading to control a printhead of a microcontroller and raises the printing quality and speed.
Still another main objective of the present invention is to provide an apparatus and a method for multichannel sequence transmission and control, in which heating units perform the heating repeatedly in a temperature range between an upper temperature limit and a temperature close to a vaporizing temperature of dyes of color ribbon by controlling the heating pulse of the heating units of the printhead.
Hence, the present invention discloses an apparatus for multichannel sequence transmission and control, which is coupled between an external microcontroller and a printhead. The apparatus comprises a bus interface, a DMA generator, a control unit, a strobe signal generator, and a data generator. The bus interface is coupled to an external microcontroller to obtain an instruction and information that are transmitted to each unit which is coupled to the bus interface. The DMA generator requests a DMA controller to operate according to a state of data buffer region of the data generator and generates a corresponding event interrupt signal according to an interrupt control register. The control unit generates a TPH shift clock and a TPH latch signal for controlling a data transmission frequency of the printhead according to an external clock signal of the external microcontroller. The strobe signal generator generates and sets strobe signals for controlling a heating of the printhead. The data generator temporarily stores a printing data controlled to write therein by one of the external microcontroller and the DMA generator, and transmits the printing data to a latch register of the printhead for printing according to the TPH latch signal.
The present invention also discloses a method for multichannel sequence transmission and control applied with an apparatus comprising a DMA generator, a bus interface, a data generator, a control unit, and a strobe signal generator. The method comprises:
a step of initial set, an external microcontroller controlling a control unit via the control unit to generate a TPH shift clock and a TPH latch signal necessary for a printhead;
a step of transmitting data, the DMA generator controlling a printing data to transmit to the data generator for buffering and to move to a latch register according to the TPH latch signal; and
a step of heating the printhead, a multiplexer activating heating units of the printhead according to a combination output generated the strobe signal generator to heat color ribbon to print, and finishing printing the printing data after an end of the strobe signals.
In one preferred embodiment of the present invention, the TPH shift clock generated by the control unit is a frequency of an external clock, provide by said external microcontroller, divided by a value set by the latch register.
In another preferred embodiment of the present invention, the strobe signals generated by the strobe signal generator have a signal period and a signal interval set according to various demands.
In still another preferred embodiment of the present invention, the data generator has a FIFO data buffer and is coupled to data pins of the printhead to transmit printing data in accordance with stored sequence.
Referring to
At least one input pin of the bus interface 1 is coupled to the external microcontroller 6 to obtain an instruction and information that are transmitted to the DMA generator 2, the data generator 3 and a strobe signal generator 4 which are coupled to the bus interface 1 to perform a corresponding action and set.
The DMA generator 2 requests a DMA controller (not shown) thereof to perform a DMA service according to a state of FIFO (fast input fact output) data buffer region (not shown) of the data generator, and handles a signal of DMA acknowledge handshake generated by the DMA controller. In addition, the DMA controller can generate a corresponding event interrupt signal according to an instruction of interrupting control register.
The data generator 3 has a FIFO data buffer region (not shown) to temporally store a designated data controlled to write in by the external microcontroller 6 or the DMA controller 2. The designated data is transmitted to a latch register 7 for printing according to a control instruction of a TPH latch signal generated by the control unit 4.
The control unit 4 generates a TPH shift clock and the TPH latch signal for controlling a data transmission frequency of the printhead according to an external clock signal transmitted by the external controller 6. The TPH shift clock is pulse signal having a frequency of the external clock, provide by the external microcontroller 6, divided by a value set by said latch register.
The strobe signal generator 5 generates strobe signals for controlling a heating of the printhead 7, and the strobe signals are set to form plural sequential and different strobe signals for controlling a heating of the printhead 7.
The strobe signal generator 5 generates plural different virtual strobe signals according to various demands, and the virtual strobe signals can corresponds to the same or different amount of strobe signals, each strobe signals having a signal period and a signal interval set according to various demands. The virtual strobe signals and actual strobe signals are combined via a multiplexer 8 to make plural heating units (not shown) of the printhead 7 have a heating time with flexible adjustment and set.
That is to say, the present invention can control the output of the actual strobe signals for controlling the heating time of the heating units via the combination of the virtual strobe signals and the actual strobe signals. As shown in
The present invention is suitable to any thermal-wax transfer printer or thermo-printer for multichannel sequence transmission and control. The present invention mainly the apparatus of multichannel sequence transmission and control to reduce the loading of the external microcontroller 6 for promoting the printing speed by cooperating to directly transmit the printing data with the DMA generator 2 while transmitting and printing the printing data. The strobe signal generator 5 control the heating pulse to form various heating effect for extending the service life and decreasing the power consumption.
The method for multichannel sequence transmission and control will be described below.
In a step of initial set, the external microcontroller 6 controls the control unit 4 via the bus interface 1 to generate the TPH shift clock and the TPH latch signal necessary for a printhead. The set step is only performed once after turning on the apparatus, and the apparatus generates a pulse signal necessary for the printhead 7 according to the external clock signal provided by the external microcontroller 6 when the set step is finished.
Next, in a step of transmitting data, a data address and a data length of the oncoming to be printed line of the printing data is designated to activate the DMA generator 2. Then, the DMA generator 2 is performed and automatically transmits the printing data to the FIFO buffer region of the data generator 3. After the data transmission is finished, the control unit 4 automatically generates the TPH latch signal and transmits the data stored in the FIFO buffer region to the latch register of the printhead 7 for an appropriate duration that is time of the printhead 7 accepting the latch signal and moving the printing data to the latch register.
In a step of heating the printhead, the signal period and signal interval of each strobe signals in the strobe signal generator 5 is set, and a setting value of the multiplexer 8 is set according to the actual layout of the printhead 7. The multiplexer 8 combines the strobe signals generated by the strobe signal generator 5 to transmit to the printhead 7. After the action mentioned above is finished, the heating units are activated with the heating time and interval according to the strobe signals generated by the strobe signal generator 5. The heating units are controlled to heat color ribbon to sublimate the color dyes for printing, and the printing of the printing data is finished after the end of the strobe signals.
The control unit 4 generates the TPH strobe signal to transmit the data to the latch register of the printhead 7. If the printhead is still in the last printing action, the latch signal automatically be delayed until the printhead 7 finishes the heating for the last printing.
Referring to
In addition,
Although specific embodiments have been illustrated and described, it will be obvious to those skilled in the art that various modifications may be made without departing from what is intended to be limited solely by the appended claims.
