JPH0811352A - Printer control device - Google Patents

Abstract

(57) [Summary] [Purpose] When performing high-density printing with a low-density head, printing is performed with paper feed for the vertical line spacing of the print image near the top and bottom edges of the paper, and in other ranges. By performing printing accompanied by a constant amount of paper feeding larger than the vertical line spacing, printing can be realized without deteriorating the printing quality and narrowing the printing area. [Structure] A vertical position checker checks whether the position of the head is near the upper and lower edges of the paper, and if it is near the upper and lower edges of the paper, print control is performed by the fine feed print control unit 7, and if it is in other areas, it is determined. The pitch feed print control unit 8 performs print control. The fine feed print control unit 7 performs printing with paper feed for the vertical line interval of the image to be printed, and the constant pitch feed print control unit 8 performs printing with a fixed amount of paper feed exceeding the vertical line interval.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer controller used in a serial printer for printing a high density image using a low density head.

[0002]

2. Description of the Related Art When printing a high-density image with a low-density head in a serial dot matrix printer, a method is generally used in which printing is performed while feeding minute paper in accordance with the vertical density of the image (hereinafter referred to as minute Referred to as feed printing). This method will be described in detail with reference to FIG. When the image indicated by black circles in FIG. 2 (a) is printed using a head having a density 1/4 of the vertical density of the image,
First, a printable line (black circle in FIG. 2B) is printed at the current print element position of the head (square mark in the figure). After that, the paper is fed by the vertical line interval m of the image, and the head is relatively moved to a position shifted downward by one line. By repeating the above operation four times (FIGS. 2C to 2E), the printing of the image shown in FIG. 2A is completed. Normally, after this, the paper is fed by the amount already printed (8 lines in the example of FIG. 2).

However, in this method, since a plurality of adjacent lines are printed by one printing element, the characteristics of the printing element are amplified, and, for example, in the example of FIG. 2, a gap or an overlap occurs every four lines. Further, in the example of FIG. 2, the paper feed for one line is performed four times and the paper feed for eight lines is performed once.
In such a case, since the paper feed pitch is not a constant value, print misalignment, overlap, etc. occur due to poor paper feed accuracy, and the print quality is significantly degraded.

As a method of solving this drawback, US Pat. No. 4,1986,642 discloses a method of feeding paper at the time of printing at a constant pitch exceeding the vertical line spacing of the image (hereinafter, constant pitch feeding). Called printing). FIG. 3 illustrates this constant pitch feed printing.
The image indicated by a black circle in (a) is the vertical density of the image of 1
The case where printing is performed using a head in which three printing elements are arranged at / 4 density intervals is shown. First, a line that can be printed at the current print element position of the head (square mark in the figure) (see FIG. 3).
The black circle in (b) is printed. Unlike the case of FIG. 2, FIG.
In (b), only one printing element at the bottom is used. After this, the paper is fed by 3 lines. In the same manner, printing and 3-line paper feeding are repeated in the same manner, and scanning is performed six times as shown in FIG.
The printing of the image shown in is completed. The constant pitch paper feed amount (amount of 3 lines in the example of FIG. 3) at this time is uniquely determined by the line density of the image to be printed, the density of print elements of the head, and the number of print elements, and the print element interval is If the head is equivalent to k lines and has n printing elements (k and n are relatively prime), paper may be fed by n lines.

In this method, adjacent lines are not printed by the same printing element, so that the drawbacks of the method shown in the example of FIG. 2 can be prevented. Further, since the paper is always fed at the same pitch, it is possible to prevent printing defects due to variations in paper feeding. However, in the process of FIGS. 3A to 3C, the head position must be above the image. No, again Fig. 3
From (f) to (g), since the position of the head is lower than the image, there is a drawback that the printing area becomes narrower than the relative movable area of the head.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a printer control device which enables high-quality printing without narrowing the printing area even when a low-density head is used. The purpose is to do.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a printer control device for controlling a printing device that prints characters / images by scanning a print head and feeding a paper, and a printer having a print density lower than a line density of an image to be printed. It has a head composed of printing elements of high density, and at the time of printing, paper is fed by the vertical line spacing for the upper and / or lower edges of the print medium, and the vertical line spacing is set for other locations. By feeding a fixed amount of paper that exceeds this, it is possible to realize high-quality printing without narrowing the printing area.

[0008]

【Example】

(Embodiment 1) FIG. 1 is a block diagram showing an outline of the present invention. When the print data is transferred from the host computer 1 to the printer 2 of the present invention through the interface, the control unit 3 analyzes the transferred print data and reads font data from the character generator (CG) 4 as necessary, The print image is written in the print buffer 9.
At this time, the control unit 3 sends the vertical position to the vertical position checker 5, and the vertical position checker 5 checks whether the current head position is within a predetermined range from the top of the page or from the bottom of the page. . If it is within a predetermined range, the channel 6 is operated and the print control is performed by the minute feed print control unit 7.
Switch to. If the vertical position is not within the predetermined range, the print control is switched to the constant pitch feed print control unit 8. The fine feed control unit 7 controls printing by the printing method shown in FIG. 2, and the constant pitch feed printing control unit 8 controls printing by the printing method shown in FIG. The print image processed by the minute feed print control unit 7 or the constant pitch feed print control unit 8 is printed in the print buffer 9.
Stored in. The data stored in the print buffer 9 is sent to the print control unit 10 by the print start command sent from the host computer 1 as a trigger, and printing is executed.

FIG. 4 is a diagram showing a printing sequence according to the present invention, and FIG. 5 is a flowchart showing a printing procedure. Details of the printing process will be described below with reference to these drawings. Here, it is assumed that the pattern "Aj" shown in FIG. 4A is printed, and that the head is positioned at the same position as the image upper end line and the head upper end print element. In addition, minute feed printing is limited to the upper edge of the image, and the range from the upper edge to two lines is performed by minute feeding printing.

First, of the unprinted lines (all lines at this point), the lines that can be printed at the current head position are developed (step 1). The line developed in this step is the line represented by the black circle in FIG. 4B, and the developed image is printed in step 2. After the printing is completed, it is checked whether the current vertical position is within a predetermined range (step 3). In this example, the position from the upper end to the position of the second line is the predetermined range, and the current position of the head is within that range, so the process moves to step 4, and in step 4, the paper is fed by one line and the current vertical position is reached. The pointer is incremented by 1 (step 6). The position of the head at this point is shown in FIG.
To move to the position of and to start the process of the next second pass.

In this example, the range from the upper end to the two lines is set as the minute feed print range, so that the third pass (see FIG. 4).
Up to (d)), the same printing as in the first pass is performed, and the printing shown in FIGS. 4B to 4D is performed by the minute feed printing method shown in FIG.

On the other hand, after the fourth pass of printing, the vertical position of the head exceeds the range of two lines from the upper end.
The check whether the vertical position is within the predetermined range (step 3) is no. In this case, the process proceeds to step 5 and paper is fed by 3 lines. The subsequent printing (FIGS. 4 (e) to 4 (i)) follows the same procedure, and printing is performed according to the constant pitch feed printing method shown in FIG.

In the example of FIG. 4, the image is described for only 16 lines in the vertical direction, but the same procedure can be repeated when the image is continuous downward.

(Embodiment 2) In the first embodiment described above, the control for executing the fine feed at the upper end of the image at the beginning of printing and for performing the constant pitch feed printing is explained. However, in the second embodiment, The control to complete the printing by performing the fine feed printing from the lower edge of the image from the constant pitch feed printing will be described below with reference to FIGS. 5 and 6.

It is assumed here that the pattern "Aj" shown in FIG. 6 (a) is printed, and the position of the head is such that the image upper end line and the head lower end print element are at the same position. In addition, for the sake of simplicity, the minute feed printing is performed only at the lower end of the image, and the minute feed printing is performed from the lower end to four lines.

First, of the unprinted lines (all lines at this point), the lines that can be printed at the current head position are developed (step 1). The line developed in this step is the line represented by the black circle in FIG. Next, the developed image is printed (step 2). Next, it is checked whether the current vertical position is within a predetermined range (step 3).
In this example, the range from the lower end to the position of the fourth line is the predetermined range, and the current position of the head is outside that range, so the process moves to step 5, and in step 5, the paper is fed by 3 lines, and the current vertical position pointer. Is incremented by 3 (step 6). At this point, the position of the head moves to the position shown in FIG.
It will be the processing of the pass. After that, the 4th pass (Fig. 6)
Up to (e)), the same printing process is performed, and the printing shown in FIGS. 6B to 6E is performed by the constant pitch feed printing method shown in FIG.

On the other hand, after the fifth pass printing, the vertical position of the head exceeds the range of 4 lines from the lower end,
The check whether the vertical position is within a predetermined range (step 3) is yes. In this case, move to step 4, 1
Line feed paper. The subsequent printing (FIGS. 6 (f) to 6 (i)) is performed according to the same procedure and the minute feed printing method shown in FIG.

(Third Embodiment) A third embodiment will be described below.

FIG. 7 is a diagram showing the printing sequence of the third embodiment, and FIG. 8 is a flow chart showing the printing procedure.
Here, it is assumed that the pattern "Aj" shown in FIG. 7A is printed, and that the head position is at the same position as the image upper end line and the head upper end print element. Further, it is assumed that the density of the printing elements is equal to the line density of the image to be printed, and when the print head is located up to two lines from the upper edge of the image, printing is performed using all the printing elements.

First, it is checked whether the current vertical position is within a predetermined range (step 11). The current vertical position of the head is at the position shown in FIG. 7B and is within the range from the upper end to two lines, so the check in step 11 is yes.
Next, move to step 12. In step 12, all print elements are used to develop printable unprinted lines. The line developed here is a line indicated by a black circle in FIG. 7B. The developed line is printed in step 14, the constant pitch paper feed for three lines is executed in step 15, the vertical position pointer is incremented by +3 in step 16, and then the second pass processing is started.

Since the head in the second pass is located on the third line from the upper end as shown in FIG. 7C and exceeds the predetermined range, the check in step 11 is no.
Then, step 13 is executed. 1 in step 13
An unprinted line that can be printed with a / 4 printing element (shown by a white square in FIG. 7C) is developed. The line developed here is the line shown by the black circle in FIG. 7C, and the developed line is printed in step 14. Then, in step 15, constant pitch paper feed for three lines is executed, and in step 16, the vertical position pointer is incremented by +3. In this way, the second-pass printing is the constant-pitch paper feed printing shown in FIG. In the third pass to the sixth pass (FIGS. 7 (d) to 7 (g)), constant pitch paper feed printing is similarly performed.

[0022]

As described above, according to the present invention, printing is performed with paper feed of one line of image at the upper or lower end of a page, and paper feed of an amount exceeding one line of image is performed in other ranges. As a result, even when a high-density image is printed using a low-density head, it is possible to minimize the deterioration of print quality.

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of a printer of the present invention.

FIG. 2 is a diagram showing a sequence of minute paper feed printing.

FIG. 3 is a diagram showing an order of constant pitch paper feed printing.

FIG. 4 is a diagram showing a printing order in an embodiment of the present invention.

FIG. 5 is a flowchart showing a printing procedure in the embodiment of the present invention.

FIG. 6 is a diagram showing a printing order in the embodiment of the present invention.

FIG. 7 is a diagram showing a printing order in the embodiment of the present invention.

FIG. 8 is a flowchart showing a printing procedure in the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Host computer 2 Printer as an example 3 Control section 4 Character generator 5 Vertical position checker 6 Channel 7 Fine feed print control section 8 Constant pitch feed print control section 9 Print buffer 10 Print control section

Claims (4)

[Claims] 1. A serial type printer control device for scanning a print head in the digit direction for recording, wherein printing is performed with a density which is an integer fraction of a dot density which forms an image to be printed among print elements which form the head. When using only elements, when printing, feed the upper and / or lower edge of the print medium by the vertical dot spacing of the image to be printed, and exceed the vertical dot spacing for other locations. A printer control device that realizes high-density printing by feeding a fixed amount of paper. 2. An upper and / or lower end of an image to be printed is fed by a vertical dot interval of the image to be printed, and at a portion other than the above, a fixed amount exceeding the vertical dot interval. 2. The printer control device according to claim 1, wherein the paper is fed. 3. In the case of printing with paper feed for the vertical dot spacing, the print elements constituting the head are used to the maximum, and in the case of printing with a fixed amount of paper feed exceeding the vertical dot spacing, An integer fraction of the dot density that makes up the image
3. The printer control device according to claim 1, wherein only the printing elements having the density of 3 are used. 4. The printer control device according to claim 1, wherein the print element which constitutes the head in advance has only an integer fraction of the image to be printed.