JP2500170Y2 - Thermal printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a thermal printer for printing print-receiving data such as document data created by a word processor on a print recording paper.

[Prior Art and Problems Thereof] Recently, thermal printers such as thermal transfer printers are widely used as printers for word processors and office automation equipment. The thermal printer sequentially reads print target data stored in advance in the print data memory according to the movement of the thermal head with respect to the print recording paper, and drives the thermal head to form an ink ribbon on the print recording paper. The thermal transfer printing is performed via the heat transfer printing, or the thermal printing is performed on the thermal recording paper.

Here, as described above, the thermal head is driven to generate heat based on the print data that is sequentially read according to its movement. This time, when printing the print data "1""black" at a certain print dot, In the case where the previous print data is “0” “white” and the print dot has not generated heat up to now, and the previous print data is “1” “black” that has generated heat up to now However, the temperatures of the two dot heating elements are different, which causes uneven printing.

Therefore, a printer with a preheating function, which performs preheating by referring to the history of past print data and determines the preheating time of the thermal head in consideration of the head temperature, the ambient temperature, the printing speed, and the like, has been considered. There is. That is, the printer determines whether or not to perform preheating based on at least one previous print data, and when preheating is performed, if the head temperature and ambient temperature of the thermal head are high, the preheating time is It is set short, and long when the head temperature and ambient temperature are low. As a result, a constant print density is always obtained.

On the other hand, the print data from the print control circuit to the thermal head is serially transferred for the purpose of simplifying the connection line. In this case, the print head starts heat generation drive at the end of this serial transfer, preheating and printing. To continuously generate heat. Therefore, if the minimum time of this preheating is shorter than the data transfer time, the heat generation drive may stop before the end of the data transfer, so it cannot be actually shorter than the transfer time.

[Purpose of the invention] The present invention has been made in view of the above-mentioned problems.
An object of the present invention is to provide a thermal printer capable of obtaining better print quality without interruption of the preheating operation before the heat generation of the thermal head is started.

[Points of Invention] That is, the thermal printer according to the present invention creates history data based on at least one previous print data and this print data, and the thermal head of each of the history data and this print data Calculates the heat generation time, and starts the heat generation of the thermal head when the calculated heat generation time of the thermal head is longer than the time required for serial transfer of the print data while the heat generation of the thermal head is not performed. After that, the serial transfer of the print data is started when the time difference elapses, and when the calculated heat generation time of the thermal head is short, after the serial transfer of the print data is started, the thermal head of the thermal head is started when the time difference elapses. Start heat generation, and the heat generation time has elapsed after the heat generation of the thermal head started. At this point, if the calculated heat generation time of the thermal head is longer than the time required for the serial transfer of the print data, the serial transfer of the print data is started when the time difference elapses with the thermal head being heated. When the calculated heat generation time of the thermal head is short, the serial transfer of the print data is immediately started while the heat of the thermal head is being generated, so that the preheating process of the thermal head and the print heat generation drive process are continued. It is composed.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of an electronic circuit of a thermal printer embodying the present invention. In FIG. 1, reference numeral 11 denotes a print control circuit. The print control circuit 11 stores print data created by, for example, a word processor. , The encoder pulse from the encoder that detects the movement amount of this printer body, the pulse count data from the encoder pulse interval counter 12 that counts the generation interval of this encoder pulse and obtains the movement speed data of the printer body, the head temperature of the thermal head 13 The head temperature detection data is input from the head temperature detection unit 14 that detects the. Here, the thermal head 13 includes, for example, a heating element of 48 dots per line, and is provided along the width direction orthogonal to the moving direction of the printer body.

On the other hand, the print data supplied to the print control circuit 11 is made up of 48-bit data corresponding to one line of the thermal head 13 in synchronization with the generation timing of the encoder pulse.
Bit-to-parallel parallel / serial converter 15
Is output to The parallel / serial conversion unit 15 performs a parallel / serial conversion operation in synchronization with a clock pulse Φ given via an AND gate AND in response to a serial data transfer command from the print control circuit 11. The serial print data from 15 is sequentially transferred to the register 16 in synchronization with the clock pulse Φ. Here, the clock pulse Φ is also given to the 48-bit counter 17. In other words, after the serial transfer of the print data is started, the carry signal (C
arry) is output to the print control circuit 11, the output of the serial data transfer command from the print control circuit 11 is stopped, and the register 16 is printed with 48 bits corresponding to one line of the thermal head 13. The data has been transferred.

The one-line print data serially transferred to the register 16 is latched in the buffer 18 in synchronization with the latch signal from the print control circuit 11 and then output to the thermal head 13 by a strobe signal from the print control circuit 11. Then, thermal transfer printing is performed.

In addition, the print control circuit 11 includes a previous print data storage unit (D ₁ ) 19 and a print data storage unit (D ₂ ) 2 before two using a RAM.
0, and the print data storage unit (D ₀ ) 21 this time are connected.
Previous print data storage unit 19 and print data storage unit 2 before 2
0, and the current print data storage unit 21 stores the thermal head 13 at the previous (one time before) print timing.
The printed data D ₁ output to the thermal head 13, the printed data D ₂ output to the thermal head 13 at the printing timing two times before (two times before), and the printed data D ₀ to be printed this time are stored. In this case, the print data D ₁ , D ₂ , and D ₀ are data corresponding to one dot of the thermal head 13, and are stored as, for example, white “0” or black “1” data.

Further, the print controller 11 is connected to the calculator 22.
The calculation unit 22 is provided with encoder interval data corresponding to the moving speed of the printer main body, which is given by the encoder pulse interval counter 12, and the previous and previous print data D given from the previous and previous print data storage units 19 and 20.
The heat generation times t _A , t _B , and t _C of the thermal head 13 at the time of this printing are calculated and determined based on ₁ and D ₂ , where t _A is determined based on the encoder pulse interval at the time of printing _two times before. , T _B is determined based on the encoder pulse interval at the previous printing, and t _C is the preset basic time t to t _A
And t _B are subtracted (t _C = T−T _A −t _B ).

Here, t _A and t _B are the preliminary heat generation time of the thermal head 13 based on the past print history, and t _C is the print heat generation time of the present print data D ₀ . In other words, the preheat t _A is obtained when the product of the print data D _{0 of} this time and the reverse data of the print data D ₂ of the previous time is “1”, that is, the thermal head at the time of print
It is necessary to generate 13 heat, and it is performed when the head is not driven by heat with the data "0" at the time of printing two times before,
Also, the preheat t _B is the current print data D ₀ and the previous print data D ₁
If the product of the reversal data of "1" is "1", that is, the thermal head 13 needs to generate heat during the current printing, and the head was not driven to heat with the data "0" during the previous printing. To be done. Therefore, for example, this time print data D ₀
There is "1", when the previous and the second previous print data D _1, D ₂ of both "0", so that the preheating t _A → t subsequently printed heating t _C to _B is performed.

Here, the preheating t _A based on time before last history data (D ₀ and inverted D ₂₎ is carried out in serial transfer of the previous history data (D ₀ and inverted D _1), also the previous history data (D ₀ and inverted
Preheating t _B based on D ₁ ) is performed during serial transfer of print data D ₀ this time. Then, the current print data D ₀ is printed by the print heating t _C.

The serial transfer time of each print data from the parallel / serial converter 15 to the register 16 is t _T.

Next, the printing operation of the thermal printer having the above configuration will be described.

FIG. 2 is a flow chart showing the print processing operation. First, the preheating time t _A based on the printer moving speed at the time of pre-previous printing obtained from the encoder pulse interval counter 12 to the print control circuit 11 is The preheating time t _B based on the printer moving speed at each time, and each preheating time t _A , t _B
The heating time t _{C of the} current printing is calculated by the calculation unit 22 from the basic time t and the basic time t (step S1). Here, the previous print data for a print dot on the thermal head 13
D ₁ = “0”, print data before last D ₂ = “0”, print data this time
Set D ₀ = “1”. Then, first, print history data (D ₀ and inversion D ₂ ) of the previous _two times is created (step S2), and serial transfer is started from the parallel / serial conversion unit 15 (step S3). After this, when the transfer of the previous-two-time print history data to the register 16 is completed (step S4), a latch signal is output from the print control circuit 11, and the two-time-before print history data is latched in the buffer 18 (step S5). Then, in the calculation unit 22, the parallel / serial conversion unit
The head preheating time t _A is subtracted from the transfer time t _{T of the} data to be transferred from 15 to the register 16 (previous printing history data: D ₀ and inversion D ₁ ) and held as T _A (step S
6). Then, it is determined whether or not T _A > 0 (step S7). If it is determined in step S7 that "No", that is, the preheat time t _A is equal to or longer than the data transfer time t _T , the print control circuit 11 immediately outputs a strobe signal to the buffer 18 to start the preheat t _A. Is done (Step S
8). Then, after the above | T _A | time has elapsed (step S
9) The previous print history data (D ₀ and reverse D ₁ ) is created (step S10), and its serial transfer is started (step S11). Thereafter, when the transfer of the previous print history data to the register 16 is completed (step S12), a latch signal is output from the print control circuit 11 and the previous history data is latched in the buffer 18 (step S17).

That is, when the preheating time t _A is longer than the data transfer time t _T , preheating of the thermal head 13 is immediately started,
Wait for the time difference T _A, and then print the next print history data (D ₀ and reverse D ₁ ).
Is transferred. Therefore, when the preheat t _A ends, the data transfer also ends.

On the other hand, if "Yes" in the step S7, that is, if it is determined that the preheating time t _A is shorter than the data transfer time t _T , first, the previous print history data (D ₀ and inversion D ₁ ) is created (step S7). Then, the serial transfer is started (step S14). Then, after the time T _{A has} elapsed (step S15), a strobe signal is output from the print control circuit 11 to the buffer 18, and preheating t _A is started (step S15).
S16). After this, the previous print history data register 16
When the transfer to (1) is completed (step S12), a latch signal is output from the print control circuit 11 and the previous history data is latched in the buffer 18 (step S17).

That is, when the preheat time t _A is shorter than the data transfer time t _T , the next print history data (D ₀ and inversion D ₁ ) is immediately output.
Transfer is started and waits for the time difference T _A. Thermal head 13
Preheating is started. Therefore, at the same time as the transfer of the previous print history data is completed, the preheating t _A is also completed, and the thermal head 13 is not in the unheated state before the start of the next preheating or the start of the print heating.

In this way, the preheating t _A of the thermal head 13 based on the print history data two times before the previous print history data (D ₀ and reverse)
D ₁ ) and the data to be transferred from the parallel / serial conversion unit 15 to the register 16 from the head preheating time t _B in the arithmetic unit 22 (current print data: D ₀ ). Transfer time t _T is subtracted and held as T _B (step S18). Then, it is determined whether or not T _B ≦ 0 (step S19). In step S19, “No”, that is, the preheating time t _B is the data transfer time.
If it is determined that it is longer than t _T, the serial transfer of the print data D ₀ this time is started after the time T _{B has} passed (step S20). After this, when the transfer of the current print data to the register 16 is completed (step S2
2) A latch signal is output from the print control circuit 11 and the print data this time is latched in the buffer 18 (step
S23). Then, after the time t _{C has} elapsed (step S24),
The output of the strobe signal from the print control circuit 11 is stopped, and the printing of the print data this time is completed (step S2
Five).

That is, when the preheating time t _B is longer than the data transfer time t _T , the preheating of the thermal head 13 is continued following the t _A , and the current print data D ₀ is transferred after waiting the time difference T _B. It Therefore, even serial transfer of this printing data D ₀ at the end of the preheating t _B ends, t _A, so that immediately the printing heating operation t _C after preheating t _B is performed.

On the other hand, if "Yes" in the above step S19, that is, if it is determined that the preheating time t _B is the data transfer time t _T or less, the serial transfer of the print data D ₀ this time is immediately started (step S21). After this, when the transfer of the current print data to the register 16 is completed (step S2
2) A latch signal is output from the print control circuit 11 and the print data this time is latched in the buffer 18 (step
S23). Then, after the time t _{C has} elapsed (step S24),
The output of the strobe signal from the print control circuit 11 is stopped, and the printing of the print data this time is completed (step S2
Five). In this case, the preheating time t _B based on the previous printing history data is shorter than the serial transfer time t _T of the current print data D _0, the preheating time data transfer time t _T without temporarily stopping the strobe signal t _B Are equal to each other, the preheating efficiency of the thermal head 13 is prevented from being lowered.

Therefore, according to the thermal printer configured as described above,
The preheating operation t _A , t _B of the thermal head 13 based on the previous and previous print history is ended at the same time as the serial transfer operation t _T of each data, and the head heating state is always stable without lowering the preheating efficiency of the thermal head 13. Print data D ₀ this time
Since the printing operation t _C can be performed, a thermal printer with high printing quality can be realized.

[Advantage of Device] As described above, according to the present invention, history data based on at least one previous print data and this print data is created, and the thermal head for each of this history data and this print data is created. The heat generation time of the thermal head is calculated, and when the calculated heat generation time of the thermal head is longer than the time required for serial transfer of the print data in a state where the thermal head is not generating heat, the heat generation of the thermal head is After the start, when the time difference elapses, serial transfer of the print data is started, and when the calculated heat generation time of the thermal head is short, the thermal head is started when the time difference elapses after the serial transfer of the print data is started. Heat generation of the thermal head, and at the time when the heat generation time has elapsed after the heat generation of the thermal head has started, When the calculated heat generation time of the thermal head is longer than the time required for the serial transfer of print data, the serial transfer of the print data is started when the time difference elapses while the thermal head is heated, and the calculated When the heat generation time of the thermal head is short, the serial transfer of the print data is immediately started while the heat generation of the thermal head is continued, and the preheating process of the thermal head and the print heat generation driving process are configured to be continuous. It is possible to provide a thermal printer capable of obtaining better print quality without interruption of the preheating operation before the heat generation of the thermal head is started.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an electronic circuit of a thermal printer according to an embodiment of the present invention, and FIG. 2 is a flow chart showing a printing operation in the thermal printer. 11 …… Print control circuit, 12 …… Encoder pulse interval counter, 13 …… Thermal head, 14 …… Head temperature detection section, 15 …… Parallel / serial conversion section, 16 …… Register, 17 …… 48-bit counter, 18 …… Buffer, 19 …… Previous print data storage, 20 …… Previously two print data storage,
21 …… This time print data storage section, 22 …… Calculation section.

Claims (1)

(57) [Scope of utility model registration request] 1. A data transfer means for serially transferring print data to be printed by a thermal head, and a history data creating means for creating history data based on at least one previous print data and this print data. A calculation unit that calculates the heat generation time of the thermal head for each of the history data created by the history data creation unit and the print data of this time, and a serial of the print data in a state where the thermal head is not heated. When the heat generation time of the thermal head calculated by the calculation means is long with respect to the time required for transfer, after starting heat generation of the thermal head, serial transfer of the print data is started at the time difference thereof,
When the heat generation time of the thermal head calculated by the calculation means is short, first heat generation control means for starting heat generation of the thermal head after the time difference has elapsed after starting the serial transfer of the print data, When the heat generation time of the thermal head by the heat generation control unit 1 has elapsed, the thermal head is heated when the heat generation time of the thermal head calculated by the calculation unit is longer than the time required for serial transfer of the print data. As it is, the serial transfer of the print data is started when the time difference elapses, and when the heat generation time of the thermal head calculated by the calculation means is short, the serial transfer of the print data is immediately started while the thermal head is heated. And a second heat generation control means.