JP3055738B2 - Dot matrix pattern printing method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of dot printers for printing a dot matrix pattern representing a character such as a character or a figure, and more particularly to a print head having two dot forming element groups. In this case, the present invention relates to a technique for allocating which dot forming element group each dot forming a dot matrix pattern is to be printed using.

[0002]

2. Description of the Related Art Some dot printers use a print head having two groups of dot forming elements in order to increase the printing speed. Generally, this type of print head includes two rows of dot forming elements (for example, printing pins) linearly arranged in the vertical direction at predetermined intervals in the horizontal direction, and is moved in the horizontal direction by the carriage. Printing while printing. In the case of using such a print head, in order to obtain the highest possible printing efficiency, 50% of the elements at the same height position in the two rows of dot forming element rows are used.
It is desirable that the driving be performed alternately at the frequency of One method for achieving this is disclosed in Japanese Patent Publication No. 62-22792. In this conventional method, for each dot of a dot matrix pattern made from a character font prepared in a font ROM, it is determined in advance which of two dot forming element rows is to be used for printing, and identification is performed. The data is stored in a memory corresponding to each dot.

[0003]

One disadvantage of this conventional method is that the frequency of use of elements at the same height in two rows of dot-forming elements does not become completely 50% each. That is, in the conventional method, the method of sorting which dot is to be printed by the element of the dot forming element row is fixedly determined in advance for each character. Therefore, when a line in which various characters are arranged is printed, the frequency of use of the dot forming element rows as the entire line is not always exactly 50%. Further, for a special character freely defined by a user, the above-described conventional method cannot be applied because the above-described identification data is not prepared in advance. further,
Even if a character in the font ROM is subjected to a modification such as shading, there is a problem that the identification data prepared in advance becomes inappropriate.

Therefore, an object of the present invention is to provide a dot printer using a print head having two groups of dot forming elements, no matter what character pattern lines are printed, The object of the present invention is to ensure that the frequency of use of the element at the corresponding position of the group is exactly 50%.

[0005]

According to the present invention, there is provided a method of printing a dot matrix pattern by using a print head in which two groups of dot forming elements are arranged apart from each other in a moving direction of a carriage. A step of preparing image data indicating each column of the pattern, and a step of preparing initial mask data for outputting all data in the first column of the image data, and using this as mask data corresponding to the first column Generating, in the second and subsequent columns, mask data corresponding to each column by an exclusive OR of the image data and the mask data of the immediately preceding column; After generating the data, the logical product of the image data indicating each column of the dot matrix pattern and the corresponding mask data is calculated. One of the dot forming element groups is driven, and the other of the dot forming element groups is driven according to a logical product of image data indicating each column of the dot matrix pattern and inverted data of the corresponding mask data. Accordingly, there is provided a method of printing a dot matrix pattern, comprising the steps of: printing each row of the dot matrix pattern.

The present invention also provides an apparatus for printing a dot matrix pattern using the above method.

This device prints a dot matrix pattern by using a print head in which two groups of dot forming elements are arranged in the moving direction of a carriage, and each column of the dot matrix pattern is shown. An image buffer for storing the image data stored therein, a mask buffer for storing the mask data corresponding to each column of the image data, and initial mask data for outputting all the data in the first column of the image data. The initial value setting means for storing this in the mask buffer as mask data corresponding to the first column, and exclusive OR of the image data and the mask data in the immediately preceding column.
Mask data setting means for generating mask data corresponding to each of the second and subsequent columns of the image data and storing the same in the mask buffer; and storing the image data for one row in the image buffer; After storing the mask data for one row corresponding to this in the mask buffer, read out the image data indicating each column of the dot matrix pattern from the image buffer,
Reading mask data corresponding to each column from the mask buffer, driving one of the dot forming element groups according to the logical product of the read image data and mask data, and inverting the read image data and mask data; Head driving means for driving the other of the dot forming element groups according to the logical product of

[0008]

First, image data indicating a dot matrix pattern of a character to be printed is prepared. Next, mask data corresponding to the dot matrix pattern is calculated based on the image data.
This mask data is data indicating which of the two dot forming element groups the dot forming element used for printing each dot of the dot matrix pattern is assigned. The calculation of the mask data is performed such that the exclusive OR of the image data indicating each column of the dot matrix pattern and the corresponding mask data is used as the mask data corresponding to the next column of each column. Will be The mask data calculated in this manner has contents such that the dot forming elements at the corresponding positions of the two dot forming element groups are used completely alternately for printing. When the mask data is created, one of the dot forming element groups is driven according to the logical product of the image data and the mask data, and the other of the dot forming element group is driven according to the logical product of the image data and the inverted data of the mask data. , The dot matrix pattern is printed. As a result, the frequency of use of the two dot forming element groups is exactly 50 regardless of the dot matrix pattern of any character.
It will be in%.

[0009]

An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a print head 1 of a printer according to an embodiment of the present invention has two print pin rows R1, R
2, each pin row is composed of nine dot printing pins 3 arranged in the vertical direction, and the two pin rows R
1, R2 are arranged laterally separated by a predetermined distance. The print head 1 is mounted on a carriage (not shown) and prints by driving the pin arrays R1 and R2 at predetermined print positions while moving in the horizontal direction.

As shown in FIG. 2, the printer 5 has a controller 7 and a printing mechanism 9 connected thereto. The controller 7 is composed of, for example, a microcomputer, and has an external host computer 11.
Then, in accordance with a print command from the host computer 11, it performs data processing and control of the printing mechanism 9 as described later. The print mechanism 9 includes all of the print head 1 described above, a mechanism for moving the head 1 such as a carriage and a carriage motor, and a mechanism for paper feed such as a paper feed roller, a paper feed motor, and a platen. It includes mechanical elements, a drive circuit for driving these mechanical elements, and various sensors for detecting their states. Since a well-known suitable mechanism can be adopted as the print mechanism 9, detailed description will be omitted.

The controller 7 has two types of buffer memories 1 called an image buffer and a mask buffer.
3 and 15. FIG. 3 shows these two buffers 13, 1
5 shows an example of the data stored in No. 5. As shown in the figure, the image buffer 13 stores bitmap data (a character portion is “1”, and the other portions are “0”) as one line in which dot matrix patterns of characters to be printed are arranged. (Hereinafter referred to as image data). Mask buffer 1
5 stores data called mask data having bits respectively corresponding to the bits of the image data.
Each bit of the mask data indicates whether each bit of the image data is to be printed by the print pin of the two print pin rows R1 and R2 (“1” is the first pin row R1,
“0” is shown as the second pin row R2).

FIG. 4 shows an overall operation flow of the controller 7. When the power is turned on, the controller 7 first performs a predetermined initial setting operation (S1), and then waits for a print command input from the host computer 11 (S1).
2). When a print command is input, first, image data and mask data for one line to be printed are expanded based on the print command (S3), and then one line print process is performed based on the data. (S4), and when the printing process is completed, a paper feeding process is performed to move to the next line (S5). Then, for each line, the above data development processing, printing processing and paper feeding processing are repeated.

FIG. 5 shows details of the data expansion process (S3) of FIG. In this process, first, the controller 7 creates image data representing one line to be printed based on the print command and develops the image data in the image buffer 13 (S
11). Since the image data can be expanded by a known appropriate method, a detailed description thereof will be omitted. In parallel with this, the mask data corresponding to the created image data is calculated (S12) and is developed in the mask buffer 15.

FIG. 6 shows the mask data calculation processing (S
The details of 12) will be described. In this process, the mask data is calculated based on the image data developed in the image buffer 13. Before describing the details of the calculation, the configuration of the image buffer 13 and the mask buffer 15 will be described with reference to FIG. Let me explain briefly. As shown in FIG. 3, these buffers 13 and 15 are addressed in the direction of the line in which the characters are arranged, and the left end of the line is address 0. And each buffer 13,
Each of the 15 address areas stores 9-bit data, and each bit of the 9-bit data defines the drive of each of the two pins R1 and R2 of the print head 1. That is, each bit of the 9-bit data in the image buffer 13 defines whether to drive the pin at the corresponding height position, that is, whether or not to print, and each bit of the 9-bit data in the mask buffer 15 The bit defines which side of the two printing pin arrays R1 and R2 is used for printing. In the following description, 9-bit image data stored in each address area of the image buffer 13 is represented by IBn (n indicates an address), and the 9-bit mask data stored in each address area of the mask buffer 15 is represented by IBn. Data is represented by MBn (n indicates an address).

Referring to FIG. 6, in this mask data calculation process, first, mask data MB of address 0
Data "111, 111, 111" is initially set to 0, and address 0 is initially set to the address pointer n (S21). This initial setting means that the printing of the address 0 is performed by the pins of the first pin row R1. After this initial setting, the process proceeds to step S22.

In step S22, an address pointer n
The exclusive OR of the mask data MBn and the image data IBn of the address n indicated by is calculated, and the resulting data is set in the mask data MBn + 1 of the next address (n + 1). This means that: That is, when a certain bit of the image data IBn of the address n is "1", that is, when a dot corresponding to that bit is printed, the same as the mask data MBn + 1 of the next address (n + 1) is obtained. The digit bit is set to a value different from that of the address n. That is, when printing is performed, the next printing is performed using pins in a printing pin array different from the previous printing. On the other hand, the image data I of the address n
When a certain bit of Bn is "0", that is, when the dot corresponding to that bit is not printed, the value of the bit of the same digit of the mask data MBn + 1 of the next address (n + 1) is the address n. Is set to the same value as that of That is, when printing is not performed, the print pin array is not changed. This is shown in Table 1.

[Table 1] IBn MBn MBn + 1 1 1 (first pin row R1) 0 (second pin row R2) (to print) 0 (second pin row R2) 1 (first pin row R1) 0 1 (first pin row R1) 1 (first pin row R1) (no printing) 0 (second pin row R2) 0 (second pin row R2) This mask data is created by incrementing the address pointer n. (S23) until the last address (right end) of the row is reached (S24). As a result, mask data having contents such that the corresponding pins of the two printing pin arrays R1 and R2 are used alternately is created.

FIG. 7 shows the details of the printing process (S4) of FIG.

First, the address pointer n is initialized to address 0 (S31). Then, the print head 1 is moved,
When the first pin row R1 of the print head 1 reaches the print position corresponding to the address n (S32), the image data I of the address n read from the image buffer 13 is read.
According to the logical product data of Bn and the mask data MBn of the address n read from the mask buffer 15, ("1"
If it is “0”, drive is performed. If “0”, drive is not performed.) The nine pins of the first pin row R1 are driven to perform printing (S33). At this time, the second pin row R2 is located at the print position corresponding to the address n + p (where p is the number of addresses corresponding to the interval between the first and second pin rows as shown in FIG. 8).
Further, the controller 7 obtains the logical product data of the image data IBn + p of the address n + p read from the image buffer 13 and the inverted value of the mask data MBn + p of the address n + p read from the mask buffer 15, and according to this ( Printing is performed by driving nine pins of the second pin row R2 (S33). The operations of steps S32 and S33 are repeated while incrementing the address pointer n (S34) until the last address (right end) of one line.

FIG. 8 shows an example of two character lines printed according to the present embodiment operating as described above. In the drawing, black dots indicate that printing is performed by pins of the first print pin row R1, and white dots indicate that printing is performed by pins of the second pin row R2. As can be seen from FIG.
Printing by the pins of the print pin row R1 and printing by the pins of the second pin row R2 are completely alternately performed, and the frequency of use of the corresponding pins in both pin rows is exactly 50%. .

The mask data for selecting the first print pin array R1 and the second print pin array R2 is created by calculation based on the image data. Font ROM
For basic patterns created from data from
Mask data can be created universally for a special pattern arbitrarily defined by the user or for a pattern that has been modified.
The frequency of use of the print pin row R1 and the second print pin row R2 is set to 50
It can be in%.

[0023]

As described above, according to the present invention,
In printing the dot matrix pattern of any character, the two print element rows of the print head can be used exactly 50% of the time.

[Brief description of the drawings]

FIG. 1 is a front view of a print head having two print pin arrays used in one embodiment of the present invention.

FIG. 2 is an exemplary block diagram showing the overall hardware configuration of the embodiment.

FIG. 3 is a diagram showing a configuration of an image buffer and a mask buffer of the embodiment.

FIG. 4 is an exemplary flowchart showing the entire processing performed by the controller of the embodiment.

FIG. 5 is a flowchart showing details of data expansion processing in FIG. 4;

FIG. 6 is a flowchart showing details of mask data development processing in FIG. 5;

FIG. 7 is a flowchart showing details of a printing process in FIG. 4;

FIG. 8 is a view showing an example of two character lines printed by the embodiment.

[Explanation of symbols]

 Reference Signs List 1 print head 3 print pin R1, R2 print pin array 5 printer 7 controller 9 printing mechanism 11 host computer 13 image buffer 15 mask buffer

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41J 2/51 B41J 2/485 G06F 3/12

Claims (2)

(57) [Claims] 1. A method for moving a group of dot forming elements by moving a carriage.
At a distance from each other in direction by using the two sequences to printhead, a method of printing a dot matrix pattern, and as engineering to prepare image data showing each row of the dot matrix pattern, first the image data 1 Output all data in column
Prepare the initial mask data that corresponds to the first column.
The mask data, and in the second and subsequent columns, the image data of the immediately preceding column
Exclusive OR of the mask data with each column
Generating mask data, and generating one row of the image data and the mask data.
After form, one of the dot forming element groups is driven in accordance with the logical product of the mask data corresponding to the image data and which indicated each column of the dot matrix pattern showed each column of the dot matrix pattern by driving the other of said dot-forming element group in accordance with the logic product of the inverted data of the image data and the mask data corresponding thereto, the dot matrix pattern with a higher engineering to print each column of the dot matrix pattern Printing method. 2. A method for moving a group of dot forming elements by moving a carriage.
Use apart from two sequences were printhead toward an apparatus for printing a dot matrix pattern, an image buffer for image data showing each row of the dot matrix pattern is stored, each of said image data A mask buffer for storing the max data corresponding to the column, and outputting all the data in the first column of the image data
Prepare the initial mask data that corresponds to the first column.
First stored in the mask buffer as mask data
Exclusive value setting means and exclusive use of image data and mask data in the immediately preceding column
By logical OR, each of the second and subsequent columns of the image data is
To generate the mask data corresponding to the column, which the previous Symbol mask
Mask data setting means for storing the image data for one line in the buffer;
And stores the corresponding one row of mask data in the previous
After storing in the mask buffer, image data indicating each column of the dot matrix pattern is read from the image buffer, mask data corresponding to each column is read from the mask buffer, and the read image data and mask data are read. Head driving means for driving one of the dot forming element groups according to the logical product of the dot forming element group and driving the other of the dot forming element group according to the logical product of the read image data and the inverted data of the mask data. Matrix pattern printing device.