JPH0796623A - Printer and driving method therefor - Google Patents

Abstract

PURPOSE:To provide a printer, by which the production cost can be reduced and the high quality printing image can be embodied. CONSTITUTION:When strobing signal STB is inputted under the condition that a selection output gate SL1 is selected by means of selection signals SEL1 and SEL2, printing data DATA stored in shift registers SR are outputted to gate elements S1, S8, S9... S256 so as to drive the gate elements corresponding to the printing data DATA. Thus, in heating resistors corresponding to the driven gate elements, electric current flows. Thus, by means of the selection signals SEL1 and SEL2, the selection gate elements SL2-SL4 are successively selected so as to execute printing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus equipped with a thermal head for performing thermal recording on a recording medium such as thermal paper, and a driving method thereof.

[0002]

2. Description of the Related Art FIG. 35 is a circuit diagram showing an electrical configuration of an example of a conventional thermal head. This thermal head is composed of a large number of heating resistors R1 to R1728 and a plurality of drive circuits 9 and the like, and in FIG.
The heat generating resistors are connected to one drive circuit 9, and the 576 heat generating resistors and the nine drive circuits 9 are divided into a total of three blocks B1 to B3 to perform a printing operation.

FIG. 36 is a circuit diagram showing an example of the drive circuit 9 shown in FIG. The drive circuit 9 outputs the print data DI composed of serial data from the external clock signal C.
A shift register S that converts the parallel data into a predetermined number of bits and outputs the parallel data by transferring in synchronization with LK.
R1 to SRn and a plurality of latch circuits L1 to Ln that store the outputs of the shift registers SR1 to SRn according to the latch signal LAT from the outside, and the latches L1 to Ln according to the strobe signal STBI and the print control signal BEO from the outside. Gate elements G1 to open and close the output of
Gn and a plurality of switching elements T1 to Tn for controlling the current flowing through the heating resistors R1 to Rn by the outputs of the respective gate elements G1 to Gn.

One end of each of a large number of heat generating resistors R1 to Rn formed on the thermal head is connected to each of the switching elements T1 to Tn.
n drain elements, the other ends of the heating resistors R1 to Rn are commonly connected to the output side VH of the external power source 70, and the source sides of the switching elements T1 to Tn are commonly connected. External power supply 7 to the terminal GND2
The ground side of 0 is connected.

This operation will be described with reference to the timing chart shown in FIG. The print data DATA for 1728 pixels formed as one scan line is input to and transferred to the shift registers SR1 to SRn of each drive circuit 9 in synchronization with the clock signal CLK, and the print signal for 64 pixels is provided in each drive circuit 9. DATA is converted into parallel data, respectively.

Next, the latch signal LAT is inverted, and the outputs of the shift registers SR1 to SRn of the drive circuit 9 are stored in the respective latch circuits L1 to Ln.

Next, when the print control signal BEO is inverted to the low level and the strobe signal STB1 is inverted to the low level, the block B composed of the heating resistors R1 to R576.
Each of the gate elements G1 to G of the nine drive circuits 9 corresponding to 1
n is opened, and each of the switching elements T1 to Tn is opened based on the print signal DATA stored in each of the latch circuits L1 to Ln.
Becomes selectively conductive. Then, the heating resistors R1 to R1
An electric current selectively flows through R576 to generate heat, heat the thermal paper or the thermal transfer film, and perform the printing operation of 1/3 of one scanning line corresponding to the block B1.

Similarly, when the strobe signal STB2 is inverted to the low level, the heating resistors R577 to R11 are similarly generated.
When a current flows selectively to 52 to generate heat, the printing operation of 1/3 of one scanning line corresponding to the block B2 is performed, and the strobe signal STB3 is inverted to a low level,
A current selectively flows through the heating resistors R1153 to R1728 to generate heat, and ⅓ of one scanning line corresponding to the block B3.
The printing operation of the part is performed. In this way, a series of images are recorded by printing one scanning line and repeating the above-described operation while stepwise conveying the thermal paper or the thermal transfer film.

[0009]

However, as shown in FIG.
In the thermal head shown in FIG.
Since it is necessary to provide the same number of shift registers SR1 to SRn, latch circuits L1 to Ln, and switching elements T1 to Tn as the number of 28, the circuit configuration of the drive circuit 9 is further complicated, and a large number of the drive circuits 9 are thermally converted. It must be mounted on the head, and there is a problem in that the manufacturing cost of the thermal head increases.

Further, when the number of drive circuits 9 is large, there is a problem that it is difficult to downsize the thermal head.

SUMMARY OF THE INVENTION An object of the present invention is to provide a printing apparatus and a driving method thereof which can simplify the driving circuit and reduce the manufacturing cost in order to solve the above-mentioned problems.

[0012]

SUMMARY OF THE INVENTION According to the present invention, a plurality of heating resistors forming print pixels and arranged in a line, and a plurality of switching elements for controlling the current flowing through each heating resistor are provided.
A plurality of gate elements for opening and closing each switching element, a shift register for converting print data composed of serial data into parallel data, and the heating resistors are divided into groups of a predetermined number n, and heat generation of each group is performed. A drive gate element that commonly connects n gate elements corresponding to resistors and opens / closes an output from a shift register in response to a strobe signal from the outside, and n select gate elements that commonly connect a plurality of gate elements. A gate element corresponding to the first heating resistor counted from the end of each odd-numbered group is commonly connected to the first selection gate element, and a gate element corresponding to the second heating resistor is The second select gate element is commonly connected, and the gate element corresponding to the nth heat generating resistor is commonly connected to the nth select gate element, One numbered the gate element corresponding to the n-th heating resistor numbered from the end of each group are commonly connected to the first selection gate element, (n-1)
The gate element corresponding to the second heating resistor is commonly connected to the second selection gate element, and the gate element corresponding to the first heating resistor is commonly connected to the nth selection gate element. From the shift register is being output from the shift register, a predetermined selection gate element is driven by a selection signal from the outside, and selection control means for driving a gate element commonly connected to the selection gate element is included. It is a characteristic printing device.

Further, according to the present invention, the position of the heating resistor is arranged in a direction intersecting with the arrangement direction of the heating resistors for each of the plurality of heating resistors corresponding to the gate elements commonly connected to the selection gate element. Characterized by shifting.

Further, according to the present invention, a plurality of heating resistors that form a print pixel and are arranged in a line, a plurality of switching elements that control a current flowing through each heating resistor, and a plurality of switching elements that open and close each switching element. A gate element, a shift register for converting print data composed of serial data into parallel data, and the heating resistors are divided into groups each having a predetermined number n, and n pieces corresponding to the heating resistors of each group. Each of the odd-numbered groups is provided with a drive gate element in which gate elements are commonly connected and an output from the shift register is opened / closed by a strobe signal from the outside, and n selection gate elements in which a plurality of gate elements are commonly connected. The gate element corresponding to the first heating resistor counted from the endmost part of is connected to the first selection gate element in common and is connected to the second heating resistor. The corresponding gate element is commonly connected to the second selection gate element, the gate element corresponding to the nth heat generating resistor is commonly connected to the nth selection gate element, and the end of each of the even numbered groups. The gate element corresponding to the n-th heat generating resistor is commonly connected to the first select gate element, and the gate element corresponding to the (n-1) th heat generating resistor is the second select gate element. When the gate elements that are commonly connected and sequentially correspond to the first heating resistor are commonly connected to the n-th selection gate element and the drive gate element outputs data from the shift register, an external selection signal And a selection control means for driving a gate element commonly connected to the selection gate element by means of a selection control unit. Print data of the heating resistor corresponding to the gate element to be selected by the means is stored in the shift register, a strobe signal is given to the driving gate element, and the gate element to be selected is driven and driven by the selection control means. A method for driving a printing apparatus is characterized in that divided printing is controlled by sequentially and repeatedly applying a current to each heating resistor corresponding to a gate element.

Further, according to the present invention, a plurality of heating resistors which form a print pixel and are arranged in a line, a plurality of switching elements which control a current flowing through each heating resistor, and a plurality of which opens and closes each switching element. A gate element, a shift register for converting print data composed of serial data into parallel data, and the heating resistors are divided into groups each having a predetermined number n, and n pieces corresponding to the heating resistors of each group. Each of the odd-numbered groups is provided with a drive gate element in which gate elements are commonly connected and an output from the shift register is opened / closed by a strobe signal from the outside, and n selection gate elements in which a plurality of gate elements are commonly connected. The gate element corresponding to the first heating resistor counted from the endmost part of is connected to the first selection gate element in common and is connected to the second heating resistor. The corresponding gate element is commonly connected to the second selection gate element, the gate element corresponding to the nth heat generating resistor is commonly connected to the nth selection gate element, and the end of each of the even numbered groups. The gate element corresponding to the n-th heat generating resistor is commonly connected to the first select gate element, and the gate element corresponding to the (n-1) th heat generating resistor is the second select gate element. When the gate elements that are commonly connected and sequentially correspond to the first heating resistor are commonly connected to the n-th selection gate element and the drive gate element outputs data from the shift register, an external selection signal Select control means for driving a predetermined selection gate element and driving a gate element commonly connected to the selection gate element, and outputting print data as serial data. Print data generating means, selection signal giving means for giving to the print data a selection signal for selecting data to be printed from the print data output from the print data generating means, and the selection signal A method for driving a printing apparatus, comprising: a selection unit that selects data to be printed from the data; and a printing data shaping unit that shapes the printing data from the selected data and outputs the printing data to a thermal head. The print data output from the means is stored in the shift register, the strobe signal is given to the drive gate element, the gate element to be selected is driven by the selection control means, and selected to each heating resistor corresponding to the driven gate element. The method for driving a printing apparatus is characterized in that the divided printing is controlled by sequentially repeating the flow of electric current.

[0016]

According to the present invention, for each gate element corresponding to the heating resistor divided into a predetermined number of groups,
Since they are commonly connected to one shift register via the drive gate element, the number of shift registers can be significantly reduced, and the scale of the heating resistor drive circuit can be significantly reduced.

According to the invention, the gate elements corresponding to the odd-numbered groups of heating resistors are commonly connected in ascending order, and the gate elements corresponding to the even-numbered groups of heating resistors are commonly connected in descending order. Having n selection gate elements, the common-connected gate elements are sequentially selected and driven by the selection gate elements, and at the same time, the print data of the heating resistors corresponding to the selectively driven gate elements are sequentially output from the shift register. To do.

Therefore, it is possible to obtain a high quality printed image in which adjacent printing dots are continuous because printing is performed by sequentially passing a current through the heating resistors corresponding to the driven gate elements.

Further, according to the invention, for each of the plurality of heating resistors corresponding to the gate element commonly connected to the selection gate, the position of the heating resistor is arranged in a direction intersecting the arrangement direction of the heating resistors. Shift. Therefore, by driving in time division for each group of heating resistors commonly connected to the selection gate element, it is possible to obtain a high quality printed image in which the printing dots are aligned.

Further, according to the invention, the selection signal for selecting the data to be printed is given to the printing data outputted from the printing data generating means by the selection signal giving means,
The data to be printed is selected by the selection means, shaped into printing data by the printing data shaping means, transferred to the shift register, and the thermal head is driven to print as described above.

Therefore, it is possible to obtain a high quality printed image in which adjacent printed dots are continuous.

[0022]

1 is a circuit diagram showing the electrical construction of a thermal head of a printer according to an embodiment of the present invention. This thermal head is composed of a large number of heating resistors R1 to R2048 arranged in a line and a plurality of drive circuits 20. In FIG. 1, the individual electrodes 21 of the 256 heating resistors are connected to one drive circuit 20, and all the heating resistors R1 to R2048 are commonly connected to the common electrode VH. Further, the heating resistors R1 to R2048
The whole is divided into block B1 and block B2, and selectively driven by corresponding strobe signals STB1 and STB2. Therefore, the strobe signal STB1 is input to each drive circuit of the block B1 and the block B2
The strobe signal STB2 is input to each of the driving circuits. Further, the print data DATA,
The control signals such as the selection signals SEL1 and SEL2 and the clock signal CLK are input.

FIG. 2 is a circuit diagram showing an electrical configuration of an example of the drive circuit 20. The drive circuit 20 outputs a print signal DI composed of serial data to a clock signal C from the outside.
A shift register S that converts the parallel data into a predetermined number of bits and outputs the parallel data by transferring in synchronization with LK.
When R1 to SR64 and the strobe signal STB (a generic term for the strobe signal STB1 and the strobe signal STB2) are input, the shift registers SR1 to SR64
Drive gate elements G1 to G64 for outputting the data from.

Four gate elements S1 to S256 for driving each heating resistor are connected in parallel to each drive gate element G1 to G64. For example, the drive gate element G1 includes gate elements S1 to S4. Are connected. The four gate elements S (collective names of the gate elements S1 to S256) connected to the drive gate elements G1 to G64 are commonly connected to the select gate elements SL1 to SL4, respectively. Drive gate elements G1 to G64 of which the output is opened or closed. The selection gate elements SL1 to SL4 are selected and driven by a combination of output levels (high level or low level) of the selection signals SL1 and SL2.

The gate elements S1 to S256 are connected to the switching elements T1 to T256, and the switching element T1.
By controlling 1 to T256, the output pad D1
Through D256, the currents flowing through the heating resistors R1 to R256 are controlled. The order of each heating resistor and the number of the gate element correspond to each other. For example, the k-th heating resistor (k is a natural number) counting from the end is connected to the gate element SLk shown in FIG. .

Further, every four heating resistors are divided into one group, and in each of the adjacent odd-numbered and even-numbered groups, in the arrangement of the selection gate elements S corresponding to the odd-numbered groups of heating resistors. , The numbers of the gate elements are in ascending order, and the numbers of the gate elements are in descending order in the arrangement of the selection gate elements S corresponding to the heating resistors of the even-numbered groups.

Here, the gate elements S of each group are commonly connected to the selection gate elements SL1 to SL4 in the order of arrangement,
For example, the gate elements S1 and S8 are selected as the first selection gate element SL1, the selection gate elements S2 and S7 are selected as the second selection gate element SL2, and the gate elements S3 and S6 are selected as the third selection gate element SL2. A gate element S4 and a gate element S5 are commonly connected to the gate element SL3 and a fourth select gate element SL4.

Further, in the drive circuit 20, instead of providing the latch circuit, the clock gate CG is provided, and when the strobe signal STB is in the active state (low level),
Since the input of the clock signal CLK is blocked, the printing data can be input to the other block while the printing of one block is being performed by the strobe signal STB.

As described above, this drive circuit 20 does not need to be provided with a latch circuit and a plurality of heating resistors are commonly connected to one shift register, so that the number of shift registers can be greatly reduced. You can As a result, the circuit scale of the drive circuit 20 can be greatly reduced.

Next, the operation of the thermal head equipped with the drive circuit 20 of FIG. 2 will be described with reference to the time chart of FIG. Block B1 and block B
In 2, the printing of one line is performed in each of four divisions, and the printing of one line is performed in each block, that is, in eight divisions. Here, the heating resistor of the block B1 and the heating resistor of the block B2 alternately print in synchronization with the strobe signal STB, and print data D1, D3, D5, D7.
Is print data of block B1, and print data D2
D4, D6 and D8 are print data of the block B2.
In addition, the print data D1 and D2 correspond to the selection gate element SL1.
The print data of the heating resistor selected by the print data D3 and D4 is the print data of the heat resistor selected by the selection gate element SL2.
Reference numerals 5 and D6 are print data of the heating resistor selected by the selection gate element SL3, and print data D7 and D8 are print data of the heating resistor selected by the selection gate element SL4. The clock signal CLK is output every number of data DATA corresponding to all the heating resistors, and the print data D1 to D8 are output in synchronization with the clock signal.

FIG. 4 shows each print data D1 shown in FIG.
The timing charts of D8 to D8 are timing charts in the case where all the data for one line is print data. The print data D1 is 8n + 1 in the block B1.
The printing data corresponding to the 8th (n is a natural number) and 8 (n + 1) th heating resistor is 8n +.
The print data is print data corresponding to the second and 8n + 7th heating resistors, and the print data D5 is 8n + 3rd and 8n + 6.
The printing data of the heating resistor corresponding to the second printing data, and the printing data D7 is the 8n + 4th printing data and the 8n + 5th printing data.

The print data D2 is print data corresponding to the 8m + 1th (m is a natural number) and 8 (m + 1) th heating resistors in the block B2, and the print data D4 is the 8m + 2,8m + 7th heating resistor. The print data D6 is print data corresponding to the body, the print data D6 is print data corresponding to the heating resistors corresponding to 8m + 3rd and 8m + 6th, and the print data D8 is 8m + 4th and 8m.
It is the print data corresponding to the + 5th heating resistor.

FIG. 5 shows printed images of the blocks B1 and B2 when printing is performed on the thermal head shown in FIG. 1 based on the timing chart shown in FIG. In the block B1, after the printing by the printing data D1, the printing by the printing data D3, the printing data D5, and the printing data D7 is sequentially performed in the paper feeding direction.
In the block B2, the print data D4, the print data D6, and the print data D8 are printed following the print data D2.
Printing is sequentially performed in the transport direction of the recording medium alternately with the printing of the block B1 described above.

Therefore, as shown in FIG. 5, a print image of a meandering line is obtained. In this print image, the print dots are evenly spaced in the print of each line, so that streaks and blurring do not occur locally. Further, in reality, the length of the heat generating resistor in the transport direction of the recording medium is sufficiently longer than the length shown in FIG. 5, so that there is almost no gap between adjacent printing dots, and printing can be performed as a continuous line. .

FIG. 6 is a time chart when the thermal head shown in FIG. 1 is driven by another driving method.
The driving method shown in FIG. 5 is different from the driving method described in FIG. 3 in that the printing data to be printed is used as a means for inputting the printing data corresponding to the heating resistors selected by the selection gate elements SL1 to SL4. Instead of processing in advance, all the print data corresponding to the order of the heating resistors are directly input as serial data.

Next, among the print data, only the clock signal CLK which is synchronized with the print data corresponding to the heating resistors selected by the selection gate elements SL1 to SL4 is input, that is, the continuous print data is required. Print data to be printed is selected and stored in the shift register. Therefore, the print data D shown in FIG. 6 are all data output in the order of the heating resistors,
The clock signals CK1 to CK8 are output in synchronization with the print data to be printed. Strobe signals STB1, ST
The output timing of B2, the selection signals SEL1 and SEL2, and the selection gate elements SL1 to SL4 is the same as the output timing shown in FIG.

Clock signals CK1, CK3, CK5, C
As shown in FIG. 7, K7 is output in synchronization with the print data to be printed in the data DB1 of the B1 block, and the clock signals CK2, CK4, CK6, CK8 are
It is output in synchronization with the data to be printed in the data DB2 of the B2 block.

FIG. 8 is a timing chart showing the output timing of the clock signals CK1 to CK8. The clock signals CK1 and CK2 are output in synchronization with the 8n + 1 (n is a natural number) and 8 (n + 1) th print data from the first print data of each block.
3 and CK4 are 8n from the first print data of each block
The clock signals CK5 and CK6 are output in synchronization with the + 2nd, 8n + 7th print data, and the clock signals CK5 and CK6 are output in synchronization with the 8n + 3rd and 8n + 6th print data from the first print data of each block.
Is 8n + 4th from the first print data of each block,
It is output in synchronization with the 8n + 5th print data. Figure 1
When the thermal head shown in FIG. 6 is printed based on the timing chart shown in FIG.
A print image shown by is obtained.

FIG. 9 is a circuit diagram showing the electrical construction of the thermal head of the printing apparatus according to another embodiment of the present invention.
This thermal head has a large number of heating resistors R1 to R20.
48 and a plurality of drive circuits 22. In FIG. 9, the individual electrodes 23 of the 256 heating resistors are connected to one drive circuit 22, and all the heating resistors R1 to R2048 are commonly connected to the common electrode VH. The entire heating resistors R1 to R2048 are divided into blocks B1 to B4. In addition, the print data DATA and the selection signal SEL1,
SEL2, strobe signal STB, clock signal CL
Each control signal such as K and the latch signal LAT is input.

FIG. 10 is a block diagram showing an electrical configuration of the drive circuit 22 of the thermal head shown in FIG.
This drive circuit 22 is similar to the drive circuit shown in FIG. 2, and the corresponding portions bear the same symbols. The difference between the drive circuit 22 of FIG. 9 and the drive circuit 20 of FIG. 2 is that the drive circuit 22 of FIG. 10 is provided with latch circuits L1 to L64.

The drive circuit 22 outputs the print signal DATA composed of serial data from the external clock signal CLK.
Shift register SR1 for converting into parallel data for each predetermined number of bits and outputting by converting the data in synchronization with
~ SR64 and external latch signal LAT
A plurality of latch circuits L1 to L64 that store the outputs of the shift registers SR1 to SR64 and drive gate elements G1 to G64 that output data from the latch circuits L1 to L64 when the strobe signal STB is input are provided. There is.

The driving gate elements G1 to G64, the selection gate elements SL1 to SL4, and the gate elements S1 to S256 drive the heating resistors in the same manner as in FIG.

Next, the operation of the thermal head equipped with the drive circuit 22 of FIG. 10 will be described with reference to the time chart of FIG. This thermal head has 4
One line is printed by division. In addition, the print data D1
Is print data of the heating resistor selected by the select gate element SL1, print data D2 is print data of the heat resistor selected by the select gate element SL2, and print data D3 is selected by the select gate element SL3. The printing data of the heating resistor is the printing data of the heating resistor, and the printing data D4 is the printing data of the heating resistor selected by the selection gate element SL4. The clock signal CLK is output every number of data DATA corresponding to all the heating resistors, and the print data D1 is synchronized with the clock signal CLK.
~ D4 is output. The print data D1 to D4 are input to the shift registers SR1 to SR64 of the drive circuits 22. Next, after outputting the print data D1 to D4, the latch signal LAT is inverted for a certain period of time, and the outputs of the shift registers SR1 to SR64 of the drive circuits 22 are changed to the latch circuit L1.
Stored in L64.

FIG. 12 is a timing chart of the print data D1 to D4 shown in FIG. 11, and is a timing chart when the data for one line is all print data. The print data D1 is print data corresponding to the 8n + 1th (n is a natural number) and 8 (n + 1) th heating resistors, and the print data D2 is 8n + 2nd, 8n +.
The printing data corresponding to the seventh heating resistor, the printing data D5 is the printing data corresponding to the 8n + 3th and 8n + 6th heating resistors, and the printing data D4 is 8
This is print data corresponding to the n + 4th and 8n + 5th heating resistors.

FIG. 13 is an image printed when the thermal head shown in FIG. 9 is used to print based on the timing chart shown in FIG. In this thermal head, after the printing with the printing data D1, the printing with the printing data D2, the printing data D3, and the printing data D4 is sequentially performed in the conveyance direction of the recording medium.

Therefore, as shown in FIG. 13, a print image of a meandering line is obtained. In this print image, the print dots are evenly spaced in the print of each line, so that streaks and blurring do not occur locally. Further, in reality, since the length of the heating resistor in the paper feeding direction is sufficiently longer than the length shown in FIG. 13, there is almost no gap between adjacent printing dots, and printing can be performed as a continuous line.

FIG. 14 is a time chart when the thermal head shown in FIG. 9 is driven by another driving method. The driving method shown in FIG. 11 is different from the driving method described in FIG. 10 in that the selection gate elements SL1 to S are selected.
As a means for inputting the print data corresponding to the heating resistor selected by L4, instead of processing the print data to be printed in advance, all the print data corresponding to the order of the heating resistors are directly input as serial data. ing.

Next, of the print data, only the clock signal CLK synchronized with the print data corresponding to the heating resistors selected by the selection gate elements SL1 to SL4 is input, that is, the continuous print data is required. Print data to be printed is selected and stored in the shift register. Therefore, the print data D shown in FIG. 14 are all data output in correspondence with the order of the heating resistors, and the clock signals CK1 to CK4 are output in synchronization with the print data to be printed. The output timings of the strobe signal STB, the selection signals SEL1 and SEL2, the latch signal LAT, and the selection gate elements SL1 to SL4 are as shown in FIG.
Since the output timing is the same as that shown by 1, the description is omitted.

FIG. 15 is a timing chart showing the output timing of the clock signals CK1 to CK4. The clock signal CK1 is 8n + 1 (n
Is a natural number) and is output in synchronization with the 8 (n + 1) th print data, the clock signal CK2 is output in synchronization with the 8n + 2nd, 8n + 7th print data from the first print data, and the clock signal CK3 is The first print data is output in synchronization with the 8n + 3rd and 8n + 6th print data, and the clock signal CK4 is output in synchronization with the 8n + 4th and 8n + 5th print data from the first print data. Even when the thermal head shown in FIG. 9 prints based on the timing chart shown in FIG. 14, the printed image shown in FIG. 13 can be obtained.

FIG. 16 is a plan view of heating resistors R1 to R2048 (generally abbreviated as "R") of a thermal head according to still another embodiment of the present invention. This thermal head is similar to the thermal head shown in FIG. 1, one end of the heating resistor R is connected to the drive circuit 20 via the individual electrode 21, and all the heating resistors R1 to R1.
R2048 is commonly connected to the common electrode VH. It should be noted that the heating resistor R of the thermal head shown in FIG. 1 is linearly arranged in the N direction, but the heating resistor R of the thermal head shown in FIG.
Are arranged in a meandering shape in the N direction.

As shown in FIG. 16, the 8n + 1th, 8n + 2nd, 8n + 3rd, 8n + 4th heating resistors, which are odd-numbered groups counting from the first heating resistor, are in the recording medium conveyance direction M. That is, the heating resistors are formed so as to be sequentially displaced from each other by a distance t in a direction intersecting the arrangement direction of the heating resistors. In addition, in the even-numbered groups, 8 (n + 1) th, 8n + 7th, 8n + 6th,
Similarly, the 8n + 5th heating resistor is formed so as to be sequentially displaced by the distance t in the transport direction M of the recording medium. That is, the position of the heating resistor is deviated for each heating resistor that is selected by the selection gate elements SL1 to SL4 and is simultaneously divided and driven.

The above-mentioned distance t is a value obtained by dividing the conveyance distance of the recording medium in the printing cycle of each heating resistor R by the number of heating resistors 4 in each group.

A case where the drive circuit 20 shown in FIG. 2 is used for the heating resistor R shown in FIG. 16 and the signals of the timing charts shown in FIGS. 3 and 4 are given will be described below. In this case, paying attention to the printing in the block B1, as shown in FIG. 4, first, 8n + 1th and 8 (n
The data D1 corresponding to the +1) th heating resistor is given to drive the heating resistor. Next, the recording medium is conveyed in the direction M by the distance t, the data D3 corresponding to the 8n + 2nd and 8n + 7th heating resistors is given, and the heating resistors are driven. Next, the recording medium is conveyed in the direction M by the distance t, the data D5 corresponding to the 8n + 3th and 8n + 6th heating resistors is given, and the heating resistors are driven. Next, the recording medium is conveyed a distance t in the direction M, and 8n + 4
Data D7 corresponding to the 8th, 8n + 5th heating resistor
Is given to drive the heating resistor.

The print image shown in FIG. 17 can be obtained by repeating the above operation. As shown in FIG. 17, the print dots of each line are arranged in a straight line, and a high-quality print image without distortion can be obtained.

FIG. 18 shows the print data D1 to D8 shown in FIGS. 3 and 4 and the clock signal C synchronized therewith.
It is a block diagram which shows the electric constitution of the circuit for generating K1-CK8. The serial data SI for printing that is output from the line memory 30 and the selectivity imparting signal SS that is output from the timing generation circuit are applied to the AND gate element MG1 and are combined. The selectivity imparting signal SS is output in synchronization with the serial data SI as shown in FIG. 19, and is divided into four types of 1 to 4 with respect to the serial data SI in order to impart selectivity to the serial data SI. The signal of is output.

As described above, the heating resistors shown in FIG. 1 are sequentially divided into groups of four, and the serial data SI corresponding to the 8n + 1 to 8n + 4th heating resistors of the odd-numbered groups in the adjacent groups is formed. The selectivity imparting signals SS of 1 to 4 are sequentially output in synchronization with each other, and 4 to 4 in synchronization with the serial data SI corresponding to the 8n + 5th to 8 (n + 1) th heating resistors of the even-numbered group. The selectivity-applying signal SS of frequency division to 1 frequency division is sequentially output.

Therefore, the combined signal SD output from the AND gate element MG1 has the same waveform as the selectivity imparting signal SS when the serial data SI is the print data as shown in FIG. It is possible to identify which signal the signal belongs to.

The composite signal SD and the selective separation signal CS output from the timing generation circuit 31 are applied to the AND gate element MG2. If the selection separation signal CS is the selectivity giving signal SS corresponding to the serial data SI to be printed that needs to be selected, the selectivity giving signal SS
If the selection giving signal SS corresponding to the serial data SI that is not printed and is not required to be selected, the phase is shifted by a half wavelength so that the signal level is inverted with respect to the selectivity giving signal SS. Output.

Therefore, the selection signal MA output from the AND gate element MG2 is the selection separation signal CS.
Corresponds to the serial data SI to be printed selected by. The selection signal MA is shaped into the pulse shape of the original serial data SI by the pulse shaping circuit 32. Therefore, only the serial data SI to be printed selected by the selective separation signal CS is transferred from the pulse shaping circuit 32 to the thermal head as the printing data DATA.

Further, the selectivity giving signal SS and the selection separation signal CS are given to the AND gate element MG3, and the AND gate element MG3 outputs the selection signal MB which is the selection giving signal SS selected by the selection separation signal CS. Is output. The selection signal MB is input to the pulse shaping circuit 34, shaped into a pulse signal synchronized with the serial data SI to be printed, and transferred to the thermal head as the clock signal CLK. That is, as shown in FIG. 19, the clock signal CLK is output in synchronization with the print data DATA to be printed.

19 to 22 are timing charts of print data D1 to D8 generated by the circuit shown in FIG. 18 and clock signals CK1 to CK8 synchronized with them. In FIG. 19, the print data D1 and D2 (collectively referred to as “DATA1”) and the clock signals CK1 and CK2 (collectively referred to as “CLK1”) corresponding to the 8n + 1th and 8 (n + 1) th heating resistors in the blocks B1 and B2, respectively.
20 is selected and output. In FIG. 20, the print data D3 and D4 (“DAT” corresponding to the 8n + 2nd and 8n + 7th heating resistors in the blocks B1 and B2 are shown.
A2 ") and clock signals CK3 and CK4
It is shown that (collectively referred to as “CLK2”) is selected and output.

Further, in FIG. 21, print data D5 and D6 (generically referred to as "DATA3") and clock signals CK5 and CK6 (generally referred to as "CLK3") corresponding to the 8n + 3th and 8n + 6th heating resistors in the blocks B1 and B2. ) Is selected and output, and in FIG.
8n + 4th, 8th in block B1 and block B2
Print data D7 and D corresponding to the n + 5th heating resistor
8 (collectively referred to as "DATA4") and clock signal CK
7, CK8 (collectively referred to as "CLK4") is selected and output.

23 to 26 are timing charts of the print data DATA1 to DATA4 generated by the circuit shown in FIG. 18 and the clock signals CLK1 to CLK4 synchronized therewith when the selection signal SS is different. As the selectivity giving signal SS in this case, signals of frequency division by 2 and frequency division by 3 which are synchronized with the serial data SI are used, and in the case of a signal of the same frequency division, two types of signals are generated by shifting a half wavelength Similar to the selection signal SS of FIGS. 19 to 22, four types of signals are output. The selectivity giving signal SS is combined with the serial data SI to give selectivity to the serial data SI. 23 to 26 corresponding to the selectivity imparting signal SS.
It changes based on the above-mentioned contents as shown by. Therefore, since the selectivity imparting signal SS uses signals of two types of frequency division, the number of frequency divisions is half that of the selection imparting signal SS shown in FIGS. The circuit and control can be simplified.

FIG. 23 shows 8 in blocks B1 and B2.
FIG. 24 shows that the print data DATA1 and the clock signal CLK1 corresponding to the (n + 1) th and 8 (n + 1) th heating resistors are selected and output.
1 shows that the print data DATA2 and the clock signal CLK2 corresponding to the 8n + 2th and 8n + 7th heating resistors in 1 and B2 are selected and output.

FIG. 25 shows that the print data DATA3 and the clock signal CLK3 corresponding to the 8n + 3th and 8n + 6th heating resistors in the blocks B1 and B2 are selected and output, and FIG. 26 shows the block B1. , B2, the print data DATA4 and the clock signal CLK4 corresponding to the 8n + 4th and 8n + 5th heating resistors in B2 are selected and output.

27 to 30 are timing charts of print data DATA1 to DATA4 generated by the circuit shown in FIG. 18 and clock signals CLK1 to CLK4 synchronized therewith when the selectivity imparting signal SS is further different. Selectivity imparting signal SS in this case
Generates one to four pulses having the same pulse width in synchronization with the serial data SI and outputs the signal as the serial data S.
By combining with I, the serial data SI is given selectivity as described above. Other signals change corresponding to the selectivity imparting signal SS as shown in FIGS. 27 to 30, based on the above-mentioned contents.

Therefore, since the selectivity imparting signal SS can be generated by a combination of the number of pulses of one kind, the generating circuit of the selectivity imparting signal SS shown in FIGS. 19 to 22 and its control method are simplified. Be converted.

FIG. 27 shows 8 in blocks B1 and B2.
28 shows that the print data DATA1 and the clock signal CLK1 corresponding to the (n + 1) th and 8 (n + 1) th heating resistors are selected and output, and FIG.
1 shows that the print data DATA2 and the clock signal CLK2 corresponding to the 8n + 2th and 8n + 7th heating resistors in 1 and B2 are selected and output.

FIG. 29 shows that the print data DATA3 and the clock signal CLK3 corresponding to the 8n + 3th and 8n + 6th heating resistors in the blocks B1 and B2 are selected and output, and FIG. 30 shows the block B.
1 shows that the print data DATA4 and the clock signal CLK4 corresponding to the 8n + 4th and 8n + 5th heating resistors in B1 and B2 are selected and output.

31 to 34 are timing charts of the print data DATA1 to DATA4 generated by the circuit shown in FIG. 9 and the clock signals CLK1 to CLK4 synchronized therewith when the selectivity imparting signal SS is further different. . Selectivity imparting signal S in this case
S generates one or two same pulse widths in synchronization with the serial data SI. In the case of the same number of pulse signals, four types of selectivity imparting signals SS are generated by shifting the phases by half a wavelength. This selectivity imparting signal imparts selectivity to the serial data SI by combining it with the serial data SI as described above. Other signals change corresponding to the selectivity imparting signal SS, as shown in FIGS. 31 to 34, based on the contents described above.

Therefore, the selectivity imparting signal SS can be generated by a combination of two pulses of one kind, as shown in FIG.
Since it is sufficient to generate a smaller number of pulses than the selectivity imparting signal SS shown in FIGS. 7 to 30, the generation circuit and the control circuit of the selectivity imparting signal SS are further simplified.

FIG. 31 shows 8 in blocks B1 and B2.
32 shows that the print data DATA1 and the clock signal CLK1 corresponding to the (n + 1) th and 8 (n + 1) th heating resistors are selected and output, and FIG.
1 shows that the print data DATA2 and the clock signal CLK2 corresponding to the 8n + 2th and 8n + 7th heating resistors in 1 and B2 are selected and output.

FIG. 33 shows that the print data DATA3 and the clock signal CLK3 corresponding to the 8n + 3th and 8n + 6th heating resistors in the blocks B1 and B2 are selected and output, and FIG.
1 shows that the print data DATA4 and the clock signal CLK4 corresponding to the 8n + 4th and 8n + 5th heating resistors in B1 and B2 are selected and output.

[0074]

As described above in detail, according to the present invention, the number of shift registers can be greatly reduced.
The scale of the drive circuit of the thermal head can be greatly reduced. Therefore, the printing apparatus can be downsized and the manufacturing cost can be reduced.

Further, according to the present invention, it is possible to obtain an image in which the adjacent printing dots are continuous, so that it is possible to prevent the occurrence of blurring and streaks due to the spacing between the adjacent printing dots. As a result, the quality of the printed image of the printing apparatus can be improved.

Further, according to the present invention, it is possible to obtain a print image in which the print dots are aligned without distortion. As a result, it is possible to further improve the quality of the printed image of the printing apparatus.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an electrical configuration of a thermal head of a printing apparatus that is an embodiment of the present invention.

FIG. 2 is a circuit diagram showing an electrical configuration of a drive circuit 20.

FIG. 3 is a time chart for explaining a driving method of the thermal head shown in FIG.

FIG. 4 is a time chart showing the contents of print data D1 to D8 shown in FIG.

5 is a print image obtained by the thermal head shown in FIG.

FIG. 6 is a time chart for explaining another driving method of the thermal head shown in FIG.

7 is a time chart showing the contents of clock signals CK1 to CK8 shown in FIG.

8 is a time chart showing the contents of clock signals CK1 to CK8 shown in FIG.

FIG. 9 is a circuit diagram showing an electrical configuration of a thermal head of a printing apparatus that is another embodiment of the present invention.

FIG. 10 is a circuit diagram showing an electrical configuration of a drive circuit 22.

FIG. 11 is a time chart for explaining a driving method of the thermal head shown in FIG.

12 is a time chart showing the contents of the print data D1 to D4 shown in FIG.

FIG. 13 is a print image obtained by the thermal head shown in FIG.

FIG. 14 is a time chart for explaining another driving method of the thermal head shown in FIG.

15 is a diagram showing clock signals CK1 to CK8 shown in FIG. 6;
It is a time chart which shows the content of.

FIG. 16 is a plan view of a heating resistor according to still another embodiment of the present invention.

FIG. 17 is a print image obtained from a thermal head including the heating resistor shown in FIG.

FIG. 18 is the print data D1 shown in FIGS. 3 and 4;
D8 and clock signals CK1 to CK8 synchronized therewith
FIG. 3 is a block diagram showing an electrical configuration of a circuit for generating the.

19 is a time chart of each signal in the circuit shown in FIG.

20 is a time chart of each signal in the circuit shown in FIG.

FIG. 21 is a time chart of each signal in the circuit shown in FIG.

22 is a time chart of each signal in the circuit shown in FIG.

23 is a time chart of each signal in the circuit shown in FIG. 9 when the selectivity imparting signals SS are different.

24 is a time chart of each signal in the circuit shown in FIG. 9 when the selectivity imparting signals SS are different.

FIG. 25 is a time chart of each signal in the circuit shown in FIG. 9 when the selectivity imparting signals SS are different.

FIG. 26 is a time chart of each signal in the circuit shown in FIG. 9 when the selectivity imparting signals SS are different.

FIG. 27 is a time chart of each signal in the circuit shown in FIG. 9 when the selectivity imparting signal SS is further different.

28 is a time chart of each signal in the circuit shown in FIG. 9 when the selectivity imparting signal SS is further different.

FIG. 29 is a time chart of each signal in the circuit shown in FIG. 9 when the selectivity imparting signal SS is further different.

FIG. 30 is a time chart of each signal in the circuit shown in FIG. 9 when the selectivity imparting signal SS is further different.

FIG. 31 is a time chart of each signal in the circuit shown in FIG. 9 when the selectivity imparting signal SS is further different.

FIG. 32 is a time chart of each signal in the circuit shown in FIG. 9 when the selectivity imparting signal SS is further different.

FIG. 33 is a time chart of each signal in the circuit shown in FIG. 9 when the selectivity imparting signal SS is further different.

FIG. 34 is a time chart of each signal in the circuit shown in FIG. 9 when the selectivity imparting signal SS is further different.

FIG. 35 is a circuit diagram showing an electrical configuration of a thermal head of a conventional printing device.

FIG. 36 is a circuit diagram showing an electrical configuration of a conventional drive circuit 9.

FIG. 37 is a time chart for explaining a driving method of the thermal head shown in FIG.

[Explanation of symbols]

 20, 22 Drive circuit 21 Individual electrode 30 Line memory 31 Timing generation circuit 32, 34 Pulse shaping circuit

Claims (4)

[Claims] 1. A plurality of heating resistors that form a print pixel and are arranged in a line, a plurality of switching elements that control a current flowing through each heating resistor, and a plurality of gate elements that open and close each switching element. , A shift register for converting print data composed of serial data into parallel data, and the heating resistors are divided into groups each having a predetermined number n (where n is a natural number), corresponding to the heating resistors of each group. The drive circuit includes a drive gate element that commonly connects n gate elements and opens / closes an output from the shift register according to an external strobe signal, and an n select gate element that commonly connects a plurality of gate elements. The gate element corresponding to the first heating resistor counted from the end of each of the groups is commonly connected to the first selection gate element, and the second The gate element corresponding to the thermal resistor is commonly connected to the second select gate element, the gate element corresponding to the nth heat generating resistor is commonly connected to the nth select gate element, and each of the even numbered The gate element corresponding to the nth heating resistor counted from the end of the group is commonly connected to the first selection gate element, and the gate element corresponding to the (n-1) th heating resistor is the second. When the gate elements commonly connected to the selection gate element and sequentially corresponding to the first heating resistor are commonly connected to the nth selection gate element, and the drive gate element outputs data from the shift register, And a selection control means for driving a predetermined selection gate element by a selection signal from the selection gate element and driving a gate element commonly connected to the selection gate element. . 2. The position of the heat generating resistor is shifted in a direction intersecting with the arrangement direction of the heat generating resistors for each of the plurality of heat generating resistors corresponding to the gate elements commonly connected to the selection gate element. The printing apparatus according to claim 1, wherein: 3. A plurality of heating resistors that form a print pixel and are arranged in a line, a plurality of switching elements that control a current flowing through each heating resistor, and a plurality of gate elements that open and close each switching element. , A shift register for converting print data composed of serial data into parallel data, and the heating resistors are divided into groups each having a predetermined number n (where n is a natural number), corresponding to the heating resistors of each group. The drive circuit includes a drive gate element that commonly connects n gate elements and opens / closes an output from the shift register according to an external strobe signal, and an n select gate element that commonly connects a plurality of gate elements. The gate element corresponding to the first heating resistor counted from the end of each of the groups is commonly connected to the first selection gate element, and the second The gate element corresponding to the thermal resistor is commonly connected to the second select gate element, the gate element corresponding to the nth heat generating resistor is commonly connected to the nth select gate element, and each of the even numbered The gate element corresponding to the nth heating resistor counted from the end of the group is commonly connected to the first selection gate element, and the gate element corresponding to the (n-1) th heating resistor is the second. When the gate elements commonly connected to the selection gate element and sequentially corresponding to the first heating resistor are commonly connected to the nth selection gate element, and the drive gate element outputs data from the shift register, And a selection control means for driving a gate element commonly connected to the selection gate element according to a selection signal from the printer. Then, the print data of the heating resistor corresponding to the gate element to be selected by the selection control means is stored in the shift register, the strobe signal is given to the drive gate element, and the selection control means drives the gate element to be selected. A method for driving a printing apparatus, characterized in that divided printing control is performed by sequentially and sequentially repeating a flow of a current selectively to each heating resistor corresponding to a driven gate element. 4. A plurality of heating resistors that form a print pixel and are arranged in a line, a plurality of switching elements that control a current flowing through each heating resistor, and a plurality of gate elements that open and close each switching element. , A shift register for converting print data composed of serial data into parallel data, and the heating resistors are divided into groups each having a predetermined number n (where n is a natural number), corresponding to the heating resistors of each group. The drive circuit includes a drive gate element that commonly connects n gate elements and opens / closes an output from the shift register according to an external strobe signal, and an n select gate element that commonly connects a plurality of gate elements. The gate element corresponding to the first heating resistor counted from the end of each of the groups is commonly connected to the first selection gate element, and the second The gate element corresponding to the thermal resistor is commonly connected to the second select gate element, the gate element corresponding to the nth heat generating resistor is commonly connected to the nth select gate element, and each of the even numbered The gate element corresponding to the nth heating resistor counted from the end of the group is commonly connected to the first selection gate element, and the gate element corresponding to the (n-1) th heating resistor is the second. When the gate elements commonly connected to the selection gate element and sequentially corresponding to the first heating resistor are commonly connected to the nth selection gate element, and the drive gate element outputs data from the shift register, The selection control means for driving a predetermined selection gate element by a selection signal from the selection gate element and the gate element commonly connected to the selection gate element, and the print data as serial data. A print data generating means for outputting the print data, a select signal giving means for giving to the print data a selection signal for selecting data to be printed from the print data outputted from the print data generating means, and the select signal A method for driving a printing apparatus, comprising: a selection unit that selects data to be printed from the data provided with, and a printing data shaping unit that shapes the printing data from the selected data and outputs the printing data to a thermal head. The print data output from the print data shaping means is stored in a shift register, a strobe signal is given to a drive gate element, and the gate element to be selected is driven by the selection control means, and each heat generation corresponding to the driven gate element is generated. A method for driving a printing apparatus, wherein divided printing control is performed by sequentially and repeatedly applying a current to a resistor.