JPH0216219B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an overlapping dot printing method that enables printing of high definition and good character quality.

Conventionally, in order to improve the print quality of a dot printer, it was necessary to increase the number of wires in the print head and reduce the diameter of the wires, which caused problems in cost and life. Therefore, an overlapping dot printing method is being considered as a means to obtain high quality characters using a simple printing head with a small number of wires.

The principle of overlapping dot printing will be briefly explained with reference to FIG. In this figure, the circle indicates the original pattern of the character. Using this original pattern as a search point, dots indicated by cross marks are inserted as interpolation points between adjacent dots in the vertical, horizontal, and diagonal directions. By applying such a procedure to all dots of the original pattern, it is expected that the quality of the characters will be improved. However, in the case of characters with a large number of strokes and a complicated structure, such a method may lead to deterioration of character quality.

FIGS. 2a to 2d show a comparison between a case where there is overlap and a case where there is no overlap. A is a case where there is no overlap, b is a case where there is overlap, and c and d are cases where there is ink bleeding due to a and b, respectively. As shown in d, it can be seen that in the part of the original pattern where the dot density is high, the white part is almost crushed.

In order to solve the above-mentioned drawbacks, the present invention provides a function to prevent duplication of characters in which the dot density of the original pattern is significantly concentrated.
This invention will be explained in detail below.

FIGS. 3 to 5 show examples of key patterns that cause characters to become "smeared" due to concentration of dots in the original character pattern. In Figure 3, C is the original pattern (hatched circle)
Denote any grid point of the complement of . FIG. 3 shows a case where the number n (shaded) of dots on the upper, lower, left and right sides of the grid point C is four. If such a dot arrangement exists, there is a possibility that the portion C will be crushed by interpolating the dot spacing in the diagonal direction.

FIGS. 4a and 4b show the case where n=3, and the number of dots adjacent to the grid point C is the minimum in a, and the maximum in b (including diagonal directions).

Figures a and b are for the case where n=2, and a and b are the states in which the number of adjacent dots is the minimum and maximum, respectively. Here, in the patterns shown in FIGS. 4b and 5b, there is a possibility that the central white portion of the parallel array of dots is destroyed by interpolation. Therefore, deterioration in character quality can be prevented by applying FIGS. 3, 4b, and 5b to the overlapping dot printing method as key patterns in which no interpolation is performed.

Next, the configuration of an interpolation selection circuit that determines a pattern in which the above-described interpolation is not performed will be described.

FIG. 6 shows the coordinates of the search points. As mentioned above, the search point C'' is one of the grid points C of the complementary set of the original pattern.The coordinates of the grid points adjacent to the search point C'' are expressed as 1 to 8 in FIG. (+1, -
1), K(0, -1), K(-1, -1), K(-1,
0), K(-1, +1), K(0, +1), K(+1,
+
1), and K(+1, 0). Note that the point coordinates of the search point C'' are K (0, 0). At this time, the status signal K _c for determining any of the key patterns in Fig. 3, Fig. 4 b, and Fig. 5 b is as follows. expressed in logic.

K _c =ABCD+A′B′C′D′(BCD+ACD+ABD+A
BC+CD +AD+AB+BC)=ABCD+A′B′C′D
'(CD+AD +AB+BC)...(1) Here, A=K(0,-1), B=K(-1,0) C=K(0,+1), D=K(+1,0) ) A′=K(+1,-1), B′=K(-1,-1) C′=K(-1,+1), D′=K(+1,+1) Kc is “ 1”, no interpolation is performed. The search point C'' moves by scanning in the grid coordinate axes I and J directions. An example of the configuration of a circuit that processes the logical expression of equation (1) is shown in FIG. 7.The processing circuit is
It can be seen that it can be easily configured using a TTL gate.

In Figure 7, G ₁ , G ₂ , G ₈ are AND gates,
G ₃ , G ₄ , G ₅ , and G ₆ are inhibit gates;
G ₇ and G ₉ are or gates.

Next, the operation will be briefly explained.

Since A, B, C, and D are input to the input of AND gate G ₁ , the operation of the first term of equation (1), that is, [ABCD] is executed, and if the result is "1", then Since “1” is output from OR gate G ₉ ,
No interpolation is performed. Also, and gate G ₂ has
Since A′, B′, C′, and D′ are input, the second term [A′B′C′D′] of equation (1) is operated, and the result is sent to the AND gate G ₈ joins one of the inputs. Also,
In inhibit gates G ₃ to _{G 6} , operations of [CD], [AD], [AB], and [BC] are performed, and if any one of them is “1”, this is the OR gate G ₇ and is applied to the other input of AND gate _G8 . the result,
“1” is output from AND gate _G8 , and this is output from OR gate _G9 . Therefore, no interpolation is performed.

FIG. 8 is a block diagram showing the configuration of an example of an apparatus for carrying out the present invention. In this figure, 11
is a font memory in which the original pattern is stored. 12 is an interpolation circuit, and font memory 11
Create a font for duplication based on this information. 13 is a selector for selecting whether or not to perform interpolation. 14 is a row buffer that stores one row. A hammer control system 15 drives a hammer (not shown) according to the line buffer 14 to perform required printing. Reference numeral 16 denotes an interpolation selection circuit which is a main part of the present invention and has the function explained in FIG. is driven to activate or deactivate the interpolation circuit 12 to perform interpolation or stop interpolation, thereby printing characters with good quality.

As explained in detail above, in this invention, the coordinates of the search point C'' to be interpolated are K(0, 0), and the coordinates of the vertical, horizontal, and diagonal grid points adjacent to this search point are K(+1 , -1), K(0, -1), K(-1,
−
1), K(-1, 0), K(-1, +1), K(0, +
1), K (+1, +1), K (+1, 0),
State signal Kc is expressed as Kc=ABCD+A′B′C′D′(CD+AD+AB
+BC) However, A=K(0,-1) B=K(-1,0) C=K(0,+1) D=K(+1,0) A'=K(+1,-1) B' = K (-1, -1) C' = K (-1, +1) D' = K (+1, +1) Find from, and if Kc is "1", no interpolation is performed,
Since interpolation is executed when Kc is "0", it is possible to determine whether or not complex character patterns overlap using a simple interpolation selection circuit, thereby preventing deterioration of character quality due to overlapping dot printing. It has the advantage of being able to

[Brief explanation of drawings]

Figure 1 is a principle diagram of the overlapping dot printing method. Figure 2 a, b, c, and d are diagrams showing changes in character quality due to overlapping dot printing. Figure 3, Figure 4 a, b, and Figure 5 a. , b are diagrams showing key patterns for determining whether or not interpolation is possible, FIG. 6 is an explanatory diagram of search points, FIG. 7 is a diagram showing a configuration example of an interpolation selection circuit according to the present invention, and FIG. 8 is a diagram showing the implementation of the present invention. 1 is a block diagram showing an example of a device for In the figure, C is a grid point, C' is a search point, 1 to 8 are grid points adjacent to search point C', 11 is a font memory,
12 is an interpolation circuit, 13 is a selector, 14 is a row buffer, 15 is a hammer control system, and 16 is an interpolation selection circuit.

Claims (1)

[Scope of Claims] 1. In an overlapping dot printing method in which a character is formed by a set of dots at matrix lattice points, and in the pattern of the character, intervals between adjacent dots with a large lattice feel are interpolated by dots, The coordinates of the search point C'' are K (0, 0), and the coordinates of the vertical, horizontal, and diagonal grid points adjacent to this search point are K (+1, -1), K (0, -1), K ( -1,
−
1), K(-1, 0), K(-1, +1), K(0, +
1), K (+1, +1), K (+1, 0),
State signal Kc is Kc=ABCD+A′B′C′D′ (CD+AD+AB+BC) However, A=K(0,-1) B=K(-1,0) C=K(0,+1) D=K(+1 , 0) A' = K (+1, -1) B' = K (-1, -1) C' = K (-1, +1) D' = K (+1, +1) ”, no interpolation is performed,
An overlapping dot printing method characterized by performing interpolation when Kc is "0".