JPH0588675B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a dot matrix printer.

(Prior Art) The printing speed of a dot matrix printer is limited by the minimum repetition drive cycle of the dot elements.

Therefore, it is well known that when the same dot element is driven successively in the lateral direction, the printing speed can be increased by operating it so that the minimum lateral dot interval (pixel interval) is increased.

An example of such a printing method is JP-A-60-
``Printing method for dot matrix printer'' disclosed in Japanese Patent No. 230867 is well known.

FIG. 2a shows a dot matrix used when printing the character "speed" at a normal speed, and is hereinafter referred to as the basic dot matrix. FIG. 2b is generated from the basic dot matrix of FIG. 2a by the algorithm shown in the above-mentioned reference, and hereinafter this will be referred to as the dot matrix for double speed printing.

Here, the minimum horizontal interval between dots in the dot matrix is one dot in Fig. 2a, but
In Figure b, there are two dots.

Therefore, when printing the dot matrix for double-speed printing shown in Figure 2b, even if the printing head is moved at twice the speed of printing the basic dot matrix shown in Figure 2a, the minimum dot element The repetition driving period is the same as when printing FIG. 2a.

By deleting one of the adjacent dots in the dot matrix by logical operation in this manner, high-speed printing becomes possible.

(Problems to be Solved by the Invention) However, in the above method, since the minimum dot spacing in the horizontal direction is twice as large, double speed printing is the limit. The present invention provides a dot matrix printer capable of high-speed printing at double speed or higher.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a dot matrix type printer for printing characters, figures, etc. in a dot matrix configuration, in which a basic dot matrix of n columns horizontally and m rows vertically is used. Means for generating a reduced dot matrix of 2/3n columns horizontally and m rows vertically from the reduced dot matrix, and a thinning dot matrix for thinning out dots to be printed from the reduced dot matrix so that dots to be printed in the same row of adjacent columns are not consecutive. means for generating a matrix; and means for increasing the moving speed of the printing head by three times the speed when printing a basic dot matrix;
The apparatus is provided with means for changing the drive cycle of the printing head so that the printing interval of dots is 3/2 times that when printing the basic dot matrix.

(Function) According to the present invention, by the first means, the horizontal n
2/3n horizontally from the standard dot matrix of columns and m rows
A reduced dot matrix with columns and m rows is generated,
Further, the second means generates a thinned-out dot matrix in which dots to be printed are thinned out from the reduced dot matrix so that dots to be printed in the same row of adjacent columns are not continuous. Furthermore, when printing a thinned dot matrix by the fourth means, the dot printing interval is 3/2 times that when printing a basic dot matrix, and the thinned dot matrix whose width is reduced to 2/3 is the same as the basic dot matrix. will be printed at the same size. If we pay attention to the horizontal minimum dot spacing in the dot matrix, it is one dot in FIG. 1a, two dots in FIG. 1c, and three dots in FIG. 1d. Therefore, even if the moving speed of the print head is increased to three times that when printing the basic dot matrix by the third means, the repetition drive period of the dot elements can be kept the same as that when printing the basic dot matrix. This makes it possible to achieve triple-speed printing.

(Example) As an example of the present invention, triple speed printing using a serial dot matrix impact printer equipped with a print head in which 24-pin print wires are arranged in two vertical rows will be described.

Before explaining triple speed printing, the mechanism of the printer will be explained using FIG. 3. In FIG. 3, numeral 1 denotes a print head, which moves left and right along the shaft 10. Reference numeral 2 denotes a belt for converting the rotational movement of the space motor 4 into reciprocating movement of the print head 1.

3 is a roller that supports the belt 2. 7 is a platen, and 8 is an LF motor that rotates the platen 7. When the LF motor 8 rotates, the platen 7 rotates, and the printing paper 9 wound around the platen 7 moves, thereby performing a feed feed operation.

A slit disk 5 is fixed to the shaft of the space motor 4 and rotates in synchronization with the rotation of the space motor 4. The amount of rotation is sent by sensor 6 to the control circuit. When printing, first, the space motor 4 is driven by the control circuit, and the print head 1 begins to move. When the print head 1 starts to move, the control circuit detects the speed and position of the print head 1 based on the signal from the sensor 6, and controls the moving speed of the print head 1 to be constant, and each time the print head 1 reaches the printing position, Drive the print wire. When the print wire is driven, it connects print head 1 and print paper 9.
Printing is performed by impacting the printing paper 9 via an ink ribbon (not shown) attached between the two.

When one line of printing is finished in this way, the control circuit
Drives the LF motor 8 to perform the changeover operation. The above operations are repeated to perform printing.

FIG. 4 shows a block diagram of the control circuit of the printer of the embodiment, in which numeral 11 is a microprocessor (CPU) that controls the printer of the embodiment, and numeral 12 is a block diagram in which programs and basic dot pattern data such as character symbols are stored. read-only memory (ROM),
13 is a random access memory (RAM) for temporarily storing data sent from the host device and for performing logical operations on dot pattern data;
4 is an I/O port for receiving character/symbol data and control data from the host device; 15 is a driver for driving the space motor 4;
The rotation of the space motor 4 is controlled according to the speed data given by the CPU 11.

17 is a driver for driving the LF motor 8;
19 is a driver for driving the print head 1 in synchronization with the drive timing pulse; 21 is a register that stores the number of sensor pulses according to the dot printing interval; and 24 is a register that counts sensor pulses to detect the position of the print head 1. This is a position detection circuit.

The circuits described above are connected to each other via the system bus 25.

Furthermore, 22 is a sensor counter that counts sensor pulses. A comparator 23 outputs a coincidence signal when the contents of the dot print timing register 21 and the contents of the sensor counter 22 match. The coincidence signal is connected to a clear input of the sensor counter 22, a dot timing input of the print head driver 19, and an interrupt input of the CPU 11. When the print head 1 moves, a sensor counter 22 counts sensor pulses synchronized with the movement. The comparator 23 clears the sensor counter 22 every time the contents of the sensor counter 22 match the contents of the dot print timing register 21, and at the same time sends a drive timing pulse corresponding to the print head driver 19 to drive the print head 1. Prints a row of dots. Furthermore, CPU1
1, an interrupt is generated to request the print head driver 19 to write the data for the next one dot row.

Therefore, the dot printing interval can be controlled by the number written in the dot printing timing register 21.

In the printer of the embodiment, one sensor pulse is generated every time the print head 1 moves by 1/480 inch, and in the normal printing mode, the dot print interval is 1/240 inch, so the dot print timing register 21 is set to 2. written. In the case of 3x speed printing, the dot printing interval is set to 3/2 times 1/160 inch, so 3 is written in the dot printing timing register 21. When the printer in the example prints,
Since the CPU 11 performs control according to the program stored in the ROM 12, the following explanation will be based on the operation of the CPU 11.

First, a method for controlling the entire printer will be explained based on FIG. When the printer is powered on, the CPU
11 receives character/symbol data from the interface section and writes it into a reception buffer prepared in RAM13.

When one line of data has been received, CPU1
1 reads the character data in the reception buffer one character at a time, reads dot pattern data corresponding to the character data from the ROM 12, and writes it into the print buffer while reducing it (the method of reduction will be described later).
Furthermore, the dot pattern data in the print buffer is thinned out (the thinning method will be described later). This process is repeated for each character and printing is performed when one line of print data is prepared. The above is the overall operation, but below we will explain how to reduce the dot pattern data for one character and put it into the print buffer as shown in Figure 5, how to thin out the dot pattern data in the print buffer, and how to thin out the dot pattern data for one line. A method for printing print data will be explained in detail. In the following explanation, the basic dot pattern data stored in the ROM 12 will be referred to as array FD, and the print data for one character secured in the print buffer will be referred to as array PD. Each element of these arrays is 24 bits long.
Written as FD, PD.

A method of reducing dot pattern data for one character and storing it in the print buffer will be explained based on FIG.

At 110, pointers I and J point to the contents of the array.
Clear. At step 111, the FD is read from the ROM and written to the PDJ. 112 is FD(I+1)
and FD (I+2) are read from the ROM 12, their logical sum is calculated, and the result is written to PD (J+1).
At 113, 3 is added to pointer I and 2 is added to pointer J. At step 114, it is checked whether the processing of one character's worth of data has been completed, and if it has not been completed, the processing is repeated from step 111.

The contents of the FD are, for example, a matrix pattern as shown in Figure 1a, and by the processing shown in Figure 6, they are transformed into a matrix pattern as shown in Figure 1b.
Written to PD.

Next, a method for thinning out the dot pattern data in the print buffer will be explained based on FIG. At step 120, 1 is placed in pointer I pointing to the contents of the array.

121, the exclusive OR of PD and PD (I-1) is computed and the AND of PD is computed to obtain PD.
write to. At 122, 1 is added to pointer I. Furthermore, process from 121 to 122 with I=24
Repeat until .

By the operation shown in FIG. 7, for example, the matrix pattern shown in FIG. 1b is converted into the matrix pattern shown in FIG. 1c.

The print data created in this way is printed by the process shown in FIG. 8, which will be explained below.

At step 130, as described above, 3 is written in the dot print timing register 21 so that the dot spacing is 1/160 inch for triple speed printing. At step 131, speed data three times the normal printing speed is written to the space motor driver 15 for triple speed printing, and movement of the print head 1 is started.

At step 132, the process waits until the print head 1 reaches the print start position. When the print start position is reached, print data for one dot row is read from the print buffer at step 133 and written to the print head driver 19.

At this point, the dot print timing register 21
Since 3 is written in , as explained in detail in the explanation of the control circuit, a coincidence signal is output from the comparator 23 every 3 sensor pulses, that is, every time the print head 1 moves by 1/160 inch, and this causes the print head to When the print data written to the driver 19 is printed, an interrupt is generated in the CPU 11. accordingly
The CPU 11 waits for an interrupt at 134 in order to synchronize with the dot printing timing.

When an interrupt occurs, position detection circuit 2 is activated at 135.
4 and detects whether the print head 1 has reached the print end position. If it has not been reached, repeat from 133. If the speed has reached 136, a speed of 0 is written to the space motor driver 15 to stop the print head 1 from moving.

(Effects of the Invention) As explained above in detail, according to the present invention, the width of the basic dot matrix used for normal printing is reduced to 2/3 times, the reduced dot matrix is further thinned out, and the dot printing interval is reduced to 3 times the width. /I doubled it, so
Since the minimum horizontal dot spacing in the dot matrix is three times that of normal printing, it is possible to print at three times the speed without having dot pattern data for triple speed printing built into the ROM or without using a high speed print head. Printing is possible at high speed. This makes it possible to provide inexpensive and high-speed printers. Furthermore, since the number of printed dots is reduced, noise can also be expected to be reduced.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram for explaining triple speed printing according to the present invention, Figure 2 is an explanatory diagram for explaining conventional double speed printing, and Figure 3 is a schematic diagram of the mechanism of a serial dot matrix impact printer. diagram showing,
FIG. 4 is a block diagram showing a control circuit according to the present invention, FIG. 5 is a flowchart explaining the printing operation of the printer, FIG. 6 is a flowchart explaining a method for reducing dot pattern data, and FIG. FIG. 8 is a flowchart illustrating a pattern data thinning method. FIG. 8 is a flowchart illustrating one line printing operation. 1...Print head, 4...Space motor, 5
... Slit disk, 6 ... Sensor, 21 ... Dot printing timing register, 22 ... Sensor counter, 23 ... Comparator, 24 ... Position detection circuit.

Claims (1)

[Scope of Claims] 1. In a dot matrix type printer that prints characters, figures, etc. in a dot matrix configuration, a reduced dot matrix of 2/3 n columns horizontally and m rows vertically is produced from a basic dot matrix of n columns horizontally and m rows vertically. A means for generating a thinned dot matrix by thinning out dots to be printed from the reduced dot matrix so that dots to be printed in the same row of adjacent columns are not continuous; It has means for increasing the dot printing interval to three times that when printing a matrix, and means for changing the drive cycle of the print head so that the dot printing interval is 3/2 times that when printing a basic dot matrix, as described above. The driving cycle of the print head is changed to make the thinned dot matrix the same size as the basic dot matrix, and the print head is moved at three times the speed when printing the basic dot matrix to perform triple speed printing. A dot matrix type printer with special features. 2. The means for generating the reduced dot matrix sequentially selects three of the basic dot matrices.
Take out columns one by one, make two consecutive columns into one column by performing a logical sum operation on the columns, leave the remaining one column as is, and create a basic dot matrix of n columns horizontally and m rows vertically by 2/3n columns horizontally and m rows vertically. A dot matrix type printer according to claim 1, characterized in that the printer is means for generating a reduced dot matrix of rows.