KR0140857B1 - The driving apparatus for thermal head - Google Patents

Abstract

A thermal head drive control circuit capable of adjusting the applied energy of the thermal head based on the printing factor information of adjacent elements including the history factor information as well as the history factor information of the heating element in order to obtain high quality printing information.

Printing processing is performed based on the history factor information of the heat generating element, the printing information of the adjacent heat generating element adjacent to the heat generating element, and the history factor information consisting of the previous printing information and the last printing information of the adjacent heating element.

As an example of a circuit for processing printing information, the OR output of the previous printing information of the adjacent heating element, the previous printing information and the AND output of the printing speed signal are taken, and the AND information of the adjacent heating element and the printing information of the adjacent heating element are OR. Let's take the output.

Description

Thermal head drive control device

1 is a circuit block diagram showing an example of a conventional drive control circuit for a thermal head.

2 is an explanatory diagram showing an example of printing a lattice help pattern.

3 is an explanatory diagram showing printing dots to be considered in the history process.

4 is a logic circuit diagram according to an embodiment of the present invention.

5 is a logic circuit diagram according to another embodiment of the present invention.

6 is a circuit block diagram of a drive control apparatus in the case of using a shift register.

Fig. 7 is an explanatory diagram showing print data in this embodiment.

8 is a circuit diagram showing an internal configuration of a history processing unit in this embodiment.

9 is an explanatory diagram showing the theory of hysteresis control and adjacent dot control.

10 is an explanatory diagram showing an internal configuration of a history processing unit in the present embodiment.

11 is an explanatory diagram showing various signals input to a printhead.

12 is a circuit diagram showing an internal configuration of a history processing unit in this embodiment.

* Explanation of symbols for main parts of the drawings

1: shift register 2: latch circuit

3a to 3n: gate circuit 4: heat generating element

12, 13, 16, 17: OR circuit 14, 15: AND circuit

26: selector 34: level setter

36: history processing part

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control device for a thermal head, in particular a device for forming a control signal for driving a heating element.

The thermal head is provided with a plurality of heat generating elements corresponding to the printing dot side by side and prints directly on the thermal paper or through an ink ribbon by selectively energizing each heat generating element of the heat generating element group installed side by side based on the printing data. It is.

In this type of thermal head, when the printing speed is increased, the next energization is started while the temperature of the heat generating element is not lowered. Therefore, there is a problem that the surface temperature of the thermal head is increased, resulting in printing spots.

In addition, when the temperature of the head is increased, there is a problem that a clock or bubbles are generated in the head due to thermal stress, and the life of the head is reduced.

Therefore, conventionally, the past heat history of each heating element is detected to control the energization time for the heating element.

FIG. 5 shows an example of a conventional drive control device, and gate circuits 3a to 3n are connected to a shift register 1 through which latch data 2 are stored, where print data is stored due to a clock signal. A plurality of heat generating elements 4 corresponding to the printing dots are connected to the circuits 3a to 3n.

According to this circuit, the print data stored in sequence in the shift register 1 is held by the latch circuit 2 and then output to the gate circuits 3a to 3n as the previous print data and simultaneously output directly from the shift register 1. The printing control data for the heating element 4 is formed based on the printing data of the present time, the printing data of the previous time, and the gate signal. For example, printing data not only at this time but also at the previous time is "Hi" (factor state). Is a control signal of a shorter pulse than when the current time is "Hi" and the previous time is "Low" (blank state).

As a result, the heat generating element 4 is given an appropriate energization time in consideration of the past heat generation state, so that a good factor can be obtained.

In addition, in the above case, the previous history may also be considered.

However, in the above-described conventional thermal head drive control apparatus, when the grid-shaped help pattern printing is performed as shown in FIG.

Therefore, it was conceivable to obtain the appropriate printing clay by controlling the driving time, the driving constant pressure, etc. of the corresponding device by referring to the adjacent factor information as well as the history factor information of the corresponding device.

However, especially in the case of the high speed factor, since the hysteresis of the adjacent device also affects the print quality, it is necessary to consider not only the history information of the corresponding device and the printing information of the adjacent device but also the history factor information of the adjacent device.

Therefore, as shown in FIG. 3, with respect to the heating element D _A to be printed, in addition to the dot D _B (D _C ) of the adjacent element, the previous time of the corresponding element, and the previous time D _D (D _G ) of the corresponding element, It is conceivable to drive in consideration of the previous dot D _E (D _F ) and the previous dot D _H (D _I ) of the adjacent element.

However, if all of those dots are considered, there are 8 dot bits to consider, and if all of them are considered, the level is divided into 256 levels, resulting in a very complicated circuit configuration and a short time for the driver of 256 levels of data. There was a problem that transmission was virtually impossible.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and the object thereof is not only the history factor information of the heating element but also the printing energy of the adjacent element including the history factor information, so that the applied energy to the thermal head can be adjusted and control is performed. It is an object of the present invention to provide a thermal head drive control apparatus which can reduce the number of bits of printing information to be considered when the circuit configuration is to be reduced, thereby making it possible to perform high-speed processing without complicated circuit configuration.

In order to achieve this object, the present invention provides a drive control apparatus for a thermal head for controlling driving based on printing information of a plurality of heat generating elements arranged side by side, the hysteresis factor information of the heat generating elements and adjacent heat generating elements adjacent to the heat generating elements. Based on the print information and the history factor information which is the last and last time print information of the adjacent heating element, the printing process is performed and the applied energy of the heating element is controlled.

Specifically, the drive control apparatus has a memory cell that stores the printing information of each element used for the processing of the printing information.

Or a first shift register for storing current printing information of the heating element group to be driven, a second shift register for storing previous history information of the heating element group, and history factor information of the previous last of the heating element group. Based on the third shift register to be stored, the history factor information of the heating element to be processed in the first, second and third shift registers, the printing factor information and the history factor information of the heating element adjacent to the heating element. A history processing section for performing history processing of the heat generating element is provided.

The above configuration allows high quality printing because the history factor information of the heat generating element, the current factor information of the adjacent element, and the history factor information are taken into consideration.

In the processing of the printing information in the above configuration, the printing information of the adjacent heating element adjacent to the heating element, the previous printing information of the neighboring heating element, and the printing information of the previous last of the adjacent heating element are output to OR and the adjacent heating element is output. Process as argument information of.

Alternatively, a switch unit for switching the previous printing information and the previous printing information of the adjacent heat generating element is provided in front of the OR output for processing.

Alternatively, the OR output of the last printing information, the previous printing information of the adjacent heating element adjacent to the heating element and the AND output of the printing speed signal are taken, and the OR output of the printing information of the corresponding AND output and the adjacent heating element is taken. Process as argument information of.

In addition, the OR output of the previous manpower factor information and the previous history factor information of the heating element is taken and processed as the history factor information of the heating element.

As described above, since the bit data to be referred to can be reduced, it is possible to construct a simple circuit configuration and to perform high-speed processing.

The energization time is controlled in the order of the prior history factor information of the heating element, the history factor information of the previous time of the heating element, and the printing information of the adjacent heating element of the heating element.

In addition, when the energization time is divided into levels in order of the prior history factor information of the heating element, the previous factor information of the previous heating element, and the printing information of the adjacent heating element of the heating element, the energization time of each factor information is equal. When it is judged that the increment function (INC) is used, the level classification can be reduced and the high speed processing can be performed.

EXAMPLE

The invention is further illustrated in detail by the following examples.

4 is a logic circuit diagram for obtaining a control signal for controlling the applied energy to each of the heating elements according to one embodiment of the present invention.

In the present embodiment, the memory cell S _A for storing the printing information of the heating element to be printed at this time, the memory cell S _B (S _C ) for storing the printing information of the heating element adjacent to the heating element, and the corresponding heat generation. Similar to the memory cell S _D for storing the previously printed information of the device, the memory cell S _G for storing the printing information for the previous time, and the memory cell for storing the previous printing information of each of the adjacent devices. _E ) (S _F ) and S _H and S _I for storing the previous printing information are shown, respectively.

Here, S _A which stores the printing information of the heating element is shown this time. The processing of the printing information of the other heating element to be printed this time uses exactly the same logic circuit, but here, only one heating element is used. It is shown.

The outputs of S _D and S _G which store the last time of the heating element and the printing information of the previous time are output as historical dot data of the heating element.

The output of the previous print information storage cell S _F and the previous print information storage cell S _I of one adjacent element is input to the OR circuit 12, and the output of the OR circuit 12 is an AND circuit 14. Is connected to one end of the input.

Similarly, the output of S _E , which stores the previous printing information of the other adjacent element, and S _H , which stores the previous printing information, is also connected to the OR circuit 13, and the output of this OR circuit 13 is an AND circuit 15. Is connected to one end of the input.

At the other end of the inputs of the AND circuit 14 and the AND circuit 15, an ON / OFF signal for selecting whether to output the hysteresis factor information of the adjacent element as a control signal is applied.

The output of the AND circuit 14 is input to one end of the OR circuit 16, the output of this time adjacent element print information storage cell is input to the OR circuit 16, and the output of the OR circuit 16 is one adjacent dot data. Is output.

Similarly, the output of the AND circuit 15 and the output of S _B which stores the printing information of the adjacent element are input to the OR circuit 17, and the other adjacent dot data is output from the OR circuit 17.

In the case of using the thermal head as a high speed factor in this embodiment circuit, the ON signal is applied to the AND circuits 14 and 15 as an ON / OFF signal.

Accordingly, the OR circuit 16 outputs one piece of printing information and the previous and previous history factor information, and the OR circuit 17 outputs the printing information of the other adjacent element, the previous printing information, and the previous printing information, respectively. do.

Based on the output of these OR circuits 16 and 17 and the history dot data of the last and last time of the corresponding device, the printing information of the adjacent device, the previous and previous time of the corresponding device, that is, the history factor information, and the history factor information of the adjacent device Are respectively referenced and output as information for controlling the applied energy applied to the heating element, and the history factor information of the adjacent element is also taken into consideration, so that high-quality printing can be performed even at high speed.

When the thermal head is used for a low speed factor, an OFF signal is applied to the other ends of the inputs of the AND circuits 14 and 15.

Accordingly, the outputs from the OR circuit 12 and the OR circuit 13 are blocked by the AND circuits 14 and 15, and only the printing information of the adjacent elements is output from the OR circuits 16 and 17. Since the control of the applied energy to the device is performed based on the printing information of the adjacent device and the history factor information of the corresponding device, the concise printing control can be performed.

In the above embodiment, the printing information of the previous and last time of the heating element is directly derived as hysteresis dot data. In another embodiment, the output of the memory cell SD (SG) is OR circuit 11 as shown in FIG. May be used as the history dot data.

In the following implementation, the shift register is configured.

In the present embodiment, as shown in FIG. 6, the first shift register 24 for storing the current print data through the selector 22 is connected to the shift register 20 for storing print data on the user area side. The first shift register 24 is connected to the second shift register 28 for storing the previous print data through the selector 26. The second shift register 28 is connected to the second shift register 28 through the selector 30. The third shift register 32 is stored.

In each of the shift registers 24, 28, and 32, the print data stored in the shift registers 24, 28, and 32 are rotated through the selectors 22, 26, 30 so as to rotate in the shift register one after another.

In addition, a level setter 34 for starting input of print processing is provided, and the history processor 36 is connected to the level setter 34.

The history processor 36 is required for history processing at predetermined positions of the first shift register 24, the second shift register 28, and the third shift register 32, in the embodiment, on the right side of the resist output terminal. The print data (A) (B) (C) (D) (E) (F) (G) (H) (I) are output.

Fig. 7 shows the interrelationship of the data for history processing. If the data of the heating element (factor dot) that is the current processing target is A, the printing data of the adjacent heating element is B, C, and this 3 The previous history factor data of the four heating elements is D, E, F and the previous history factor data is G, H, I.

In this case, therefore, the data of B to H are used to determine the printing information of the A data, and the information of these heating elements is sequentially changed according to the conversion dome by the operation of the shift registers 24, 28 and 32. It becomes possible to perform a process.

FIG. 8 shows a specific circuit configuration in the history processor 36. In the drawing, the memory cells SA to SI correspond to shift registers 24 and 28 corresponding to the printing data of the heating element shown in FIG. (32) shows the memory cell.

The outputs of both the memory cells SD and SG are historical dot data as they are.

In addition, an OR circuit 43 for taking a logical sum of both outputs of the memory cells SF and SI is provided, and the output of the OR circuit 42 is supplied to the AND circuit 44, and the output of one OR circuit 43 is ANDed. It is output to the circuit 45.

The AND circuits 44 and 45 are supplied with an ON / OFF signal for switching the control state by the low speed factor and the high speed factor, and the logic of the ON / OFF signal and the outputs of the OR circuits 42 and 43 are supplied. Configured to take the product.

An OR circuit 46 which takes a logical sum of the output of the memory cell SC and the output of the AND circuit 44, and an OR circuit that takes a logical sum of the output of the memory cell SB and the output of the AND circuit 45 ( 47) is provided, and adjacent dot data is output from these OR circuits 46 and 47.

An embodiment consists of the above structure and demonstrates its operation below.

First, when the power is turned on and when the reset signal is input, the first shift register 14, the second shift register 28, and the third shift register 32 are cleared, and the shift register 20 of the user area is cleared. Printing data is input by the user.

If there is a load input, the print data moves from the shift register 20 in the user area to the first shift register 24 through the selectors 22 (101 → 102), and the selector in the first shift register 24. (26) (104 → 106) to the second shift register 28 and the second shift register 18 to the third shift register 32 in turn via the selector 30 (108 → 110). .

Therefore, the first shift register 24 stores the print data at this time, the second shift register 28 has the previous print data, and the third shift register 32 stores the previous print data.

Next, when the first start input is input to the level setter 34, the level setter 34 operates at the level 1 and the first, second and third shift registers 24, 28 and 32 are operated. The data inside is moved while rotating in the directions of 103 → 105, 107 → 109, 111 → 112, and the print data A to I are supplied to the history processor 36.

Then, in the OR circuits 42 and 43 of FIG. 8, the logical sum of the last and last time print data of the adjacent heat generating elements is calculated, and the output of the memory cell SG SD is output as the history factor data as it is.

On the other hand, the output of the OR circuit 42 is the AND circuit 44, and the output of the OR circuit 43 can take a logical product with the ON / OFF signal that determines whether or not the AND circuit 45 performs hysteresis processing. Will be.

In this case, since the ON signal Hi is output to the AND circuits 44 and 45 when the high speed factor is applied, the AND circuit 44 (if the output of the OR circuits 42 and 43 is "Hi"). The output of 45) becomes "Hi".

Next, the outputs of the ANDs 44 and 45 are ORed by the OR circuits 46 and 47, and the ORs 46 and 47 are logically summed with the printing data of the adjacent heat generating elements, and the OR circuits 46 and 47 output the adjacent dot data.

Therefore, the "Hi" and "Low" are outputted as history dot data as the history information of the corresponding heat generating element. In addition, the OR circuits 46 and 47 display three pieces of print data of the adjacent heat generating element and this history factor data. If any of the print data is "Hi", adjacent dot data of "Hi" is output.

In this manner, when the history processing of the level 1 is completed, the start signal of the next level is output, and the level setting unit 34 sequentially raises the levels 2 to 6, and the history processing unit ( In 36, history data is output together with the clock signal.

As described above, the printing information of the heating element, the history information of the previous and previous times of the heating element, and the printing and history information of the adjacent heating element are generated by the history information and the 4-bit output of the OR circuits 46 and 47. Are referenced respectively, and the applied energy of the heating element is controlled.

The control of the applied energy is carried out by controlling the energization time, and is configured such that the temperature of each heat generating element is constant by having a drop in the energization time.

Basically, as shown in FIG. 9, when the heat generating element heats up last time, since heat energy remains, it is completed with a short energization time, and when the heat generating element heats up last time, it is energized longer than when heating the previous time. In the case of single heat generation, hysteresis control is performed by energizing longer than the case of the previous heat generation.

On the other hand, the control of the adjacent dots is completed in a short energization time so that the slope of the heat rise is increased and the peak temperature is reached in a short time because the heat does not run to the side when the adjacent dots generate heat.

Specifically, as shown in FIG. 10, the type of driving pulse is divided into six levels and controlled by the four-bit output note.

In other words, when the energization time of A to F is set and the history dot data and the adjacent dot data are "Low", a driving pulse of the maximum length (A to F) indicated in level (1) is formed, but the adjacent dot data is "Hi". (Heating state), a driving pulse determined by B to F is formed like the level (2).

Level 3 is a driving pulse composed of C to F time by subtracting B time, for example, when the previous dot data of the heating element is "Hi", and level 4 indicates that the dot data and the adjacent dot data of the previous dot are "Hi." Drive pulses consisting of D to F time, for example, " Hi ", and driving pulses for E and F time, for example, when the previous dot data is " Hi, " When the data is " Hi ", the drive pulse is composed of F time, and the above drive pulses are formed by the heat generation state of elements other than the heat generating element, and are given to the heat generating element.

As for the history information of the adjacent heat generating element, for example, when the low-speed factor (OFF state) is shown in the level 3, when the previous adjacent dot data is "Hi", the history information is not considered, but the level 4 is not displayed. As shown in the figure, in the case of the high speed factor (ON state), when the previous adjacent dot data is "Hi", a driving pulse having a short D-F time with C time subtracted is formed.

The data output shown in FIG. 6, the history data in the history processing section, and the like are input to the controller IC as shown in FIG. 11 to control the energization of each heat generating element of the printhead.

This printhead is 640 dots type, as shown in the figure.

[DI] shown in FIG. 11 indicates data input, and historical data is input to "START" in FIG.

In Fig. 11, the "VDD" signal applies a power supply voltage, and the "LOAD" signal is for inputting and holding print data to the CONTROL IC.

The "E-OUT" signal in Fig. 11 is output when a transport error of print data occurs.

The clock output of the history processor 36 of FIG. 6 corresponds to the "CP" signal, and "DO" means "DATA OUT" and print data is output.

The "SET" signal sets all the control data of the CONTROL IC to 1, while the "RESET" signal sets all the control data of the CONTROL IC to 0.

In addition, since the printhead is 640 dots, each of the shift registers 10, 14, 18, and 22 may also correspond to 640 dots.

In addition, "OR-ON" in FIG. 11 is a signal for enabling or invalidating the history data of the adjacent element. When the ON / OFF signal is input as in the above embodiment, it is not input because it fulfills its role.

According to the history processing section 36 composed of the logic circuit shown in FIG. 8, high speed operation is possible, so that the history processing can be performed at a rate of several nsec / bit, and the history information of the adjacent heat generating element is also taken into consideration. Then, high quality printing can be performed.

The printing data used for the history processing is rotated by the shift registers 24, 28 and 32, and the history processing section 36 performs the serial processing in synchronism with the rotation of the data. can do.

That is, when the above hysteresis processing is performed by applying the circuit shown in Fig. 5, most of the gate circuits must be organized, which not only complicates the configuration but also makes the chip size larger and costly. .

In addition, when the thermal head is used as a low speed factor, the AND circuits 44 and 45 are blocked and only the printing data of the adjacent heat generating elements is output from the OR circuits 46 and 47. The control of energy is only output of the printing data of the adjacent heating element, and in this case, the control of the applied energy of the heating element is performed based on the printing data of the adjacent heating element and the history factor information of the heating element. can do.

The embodiment shown next is substantially the same as the above embodiment, but as shown in FIG. 12, the history processor 36 OR-outputs the previous printing information of the heating element and the previous printing volume of the heating element. In this case, higher speed processing can be performed.

In the above embodiment, as shown in FIG. 3, the printing information and the history factor information of the left and right adjacent heating elements are considered by combining three pieces of information, but in addition, the printing information of the adjacent heating elements and the history factor information of the adjacent heating elements are also considered. Extraction may be performed separately.

In addition, although the history factor information of the adjacent heat generating element considers the information of the last time and the previous time, it is also possible to process the history only with the last time information.

As described above, according to the present invention, since the history processing is performed based not only on the history factor information of the heating elements, but also on the printing information of the adjacent heating elements, the previous printing information of the adjacent heating elements and the printing information of the previous heating elements, the printing of the grid-shaped help pattern is performed. High quality printing can also be performed.

In the case of using a shift register, printing information can be obtained at high speed and easily by a simple circuit configuration.

The OR information of the printing information of the adjacent heating elements adjacent to the heating element, the printing information of the previous heating element of the adjacent heating element, and the printing information of the previous printing of the adjacent heating element are OR output and the printing information of the previous previous heating element of the adjacent heating element adjacent to the heating element. OR output and OR output of the last printing information of the adjacent heating element adjacent to the heating element, the OR output of the previous printing information and the AND speed of the printing speed signal, and OR output of the corresponding AND output and the printing information of the adjacent heating element. In case of taking OR output of the previous history factor information of the heating element and the previous history factor information, the bit data to be referred to is reduced when the OR output of the previous history factor information and the previous history factor information of the heating element is taken. Because it can be done, it can be processed at high speed with a simple circuit configuration.

In particular, in the case where a switch section for turning on / off the last printing information and the last printing information of the adjacent heating element adjacent to the heating element is provided, the last printing information and the previous printing information of the neighboring heating element adjacent to the heating element are provided. In the case of taking the OR output and the AND output of the print speed signal and the OR output of the AND output and the print information of the adjacent heating element, the processing taking into account the print processing speed can be performed.

Claims (7)

A drive control apparatus for a thermal head which executes drive control based on printing information of a plurality of heat generating elements arranged side by side, comprising: (a) history factor information of a heat generating element comprising previous and last time printing information of the heat generating element; (b) printing information of adjacent heating elements adjacent to the heating element; And (c) processing means for performing processing of the printing information on the basis of the history factor information comprising the previous and last printing information of the adjacent heat generating elements; Switching means for enabling and disabling processing of adjacent heating element history factor information in processing means based on whether the thermal head is a low speed factor or a high speed factor; Control means for controlling the applied energy of the heating element according to the printing information processed by the processing means; A first shift register for storing current printing information of the heating element; A second shift register for storing last history factor information of the heating element; A third shift register configured to store previous last history factor information of the heating element; And a history processing unit configured to input history factor information of the corresponding heating element and history factor information of the adjacent heating element from the first, second, and third shift registers, and execute history processing of the corresponding heating element based on the input information. Drive control device of the thermal head, characterized in that. The thermal head of claim 1, wherein the printing information of the adjacent heating element adjacent to the heating element and the previous and previous printing information of the adjacent heating element are ORed and processed as printing information of the adjacent heating element. Drive control system. 3. The drive control apparatus for a thermal head according to claim 2, wherein the ON / OFF operation for the previous time and the previous time printing information of an adjacent heat generating element adjacent to the heat generating element is executed. The method according to claim 1, wherein the OR output of the previous and previous printing information of the adjacent heating element adjacent to the heat generating element and the AND output of the printing speed signal are taken, and the OR output of the corresponding AND output and the printing information of the adjacent heating element is taken. And drive processing apparatus for thermal head as printing information of an adjacent heat generating element. 3. The drive control apparatus for a thermal head according to claim 1 or 2, wherein the OR output of the previous history factor information and the previous history factor information of the heating element is taken and processed as the history factor information of the heating element. 5. The thermal head according to claim 4, wherein the energization time is controlled in the order of the prior history factor information of the heating element, the previous history factor information of the heating element, and the printing information of the adjacent heating element of the heating element. Drive control system. The method according to claim 1 or 2, wherein the energization time is controlled in the order of the previous history factor information of the heating element, the previous history information of the heating element, and the printing information of the heating element. A drive control apparatus for a thermal head, characterized in that it has a controllable function skipped.