JP3027859B2 - Multicolor printing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a multi-color printing apparatus that prints characters and figures in a desired color by forming a figure and superimposing and recording each dot in a plurality of colors. The present invention relates to a color printing device.

[0002]

2. Description of the Related Art In recording by a laser printer, ink jet, thermal transfer, or the like, characters and figures are formed as a set of dots. FIG. 8A shows an example of a case where a diagonal line is composed of a plurality of dots, and shows a part of the diagonal line. 8 in the figure
Reference numeral 0 denotes each dot constituting a character or a figure, and is a portion actually recorded by a printing apparatus such as a laser printer, an ink jet, and a thermal transfer. 81 indicates a plurality of dots 80
Shows an imaginary outline of a diagonal line composed of.

If a diagonal line is formed by a set of dots 80, the diagonal line recorded as understood by the outline 81 in FIG. 8A becomes jagged, resulting in poor print quality. Fig. 8 (2)
This is one method for eliminating such jagged oblique lines. A micro dot 82 smaller than the dot 80 is added adjacent to the dot 801 located at the hatched outline. Fig. 8 (3)
It is a partially enlarged view of FIG. 8 (2). Fig. 8 (2), contour (8) in (3)
As can be understood from FIG. 1, the addition of the microdots 82 can reduce the jaggedness of oblique lines.

On the other hand, devices for printing characters and figures in color have been researched and developed. FIG. 6 shows an example of such an apparatus, which is an apparatus for printing by electrophotographic recording. 60 is
It is a paper supply device. The sheet supplied from the sheet supply device 60 is sent by a transport belt 61. 62-65
Are apparatuses for performing electrophotographic recording with the same configuration, and differ only in the color in which recording is performed. Each of the recording devices 62 to 65 performs recording in the colors of yellow Y, magenta M, cyan C, and black B.

When recording is performed in chromatic colors other than yellow Y, magenta M, and cyan C, overlapping recording is performed. Red is overprinted by a combination of yellow Y and magenta M, that is, by the recording devices 62 and 63. Blue is a combination of magenta M and cyan C and overprinted by the printing devices 63 and 64, and green is a combination of yellow Y and cyan C and overprinted by the printing devices 62 and 64.

[0006] The recording devices 62 to 65 have the same configuration, and the recording device 63 will be described as an example. A cleaner 601 has a function of removing magenta M color toner attached to the photosensitive drum 602. 603, a charger;
It has a function of charging the drum surface of the photosensitive drum 602 with a positive charge by corona discharge. Reference numeral 604 denotes a latent image forming device. A latent image is formed by canceling out the charge of the character or graphic portion to be printed corresponding to the print data from the control device 66 among the charge on the drum surface of the photosensitive drum 602. In this part, the laser printer applies a laser beam to a character or graphic part to be printed, thereby canceling the charged charges.

Reference numeral 605 denotes a developing device, which develops and attaches a positively charged magenta M color toner to a latent image formed by canceling a charge by a laser beam on a photosensitive drum 602. The photosensitive drum 602 to which the color toner has adhered rotates, and the color separation unit 606 transfers the color toner to the sheet fed by the transport belt 61. Transfer separation device 606
Has a function of separating the paper on which the color toner is transferred so that the paper does not adhere to and get caught in the photosensitive drum 602. Accordingly, the paper on which the color toners have been transferred by the recording devices 62 to 65 is sent to the fixing device 64 by the transport belt 61. Here, the toner is heated and the color toner is fixed on the paper, and printing is completed.

When printing is performed in a chromatic color other than yellow Y, magenta M, and cyan C, overprinting is performed by two or more of the printing devices 62 to 65, but it is necessary to match the positions of the overprinting. It is. However, since tension is applied to the paper and the paper is fed by a mechanical transport belt 61, it is required to perform extremely precise control to correctly stop the necessary one of the recording devices 62 to 65. For this reason, it is difficult to perform overprinting so as to match the printing position of the preceding printing apparatus.

[0009]

FIG. 7 (1) shows an example in which microdots are added to the outline of a hatched portion in the same manner as in FIG. 8 and printing is performed in a green color by overprinting using the printing apparatus of FIG. Is shown. FIG. 7 (2) is a partially enlarged view of FIG. 7 (1).
To print in the green color, the recording device 62 for recording in yellow Y and the recording device 64 for recording in cyan C perform overprinting. 7, 80-1 and 82-1 are:
These are dots and microdots recorded in yellow Y by the recording device 62, respectively. 80-2 and 82-2 are
These are dots and microdots recorded in cyan C by the recording device 64, respectively.

As described above, it is difficult to make the recording positions coincide during the overprinting, and as can be understood from FIG. 7, the recording positions of the recording device 62 and the recording device 64 do not coincide and are shifted in the direction of the arrow. . The recorded microdot 82-
Paying attention to 1 and 82-2, the recording position is shifted, and the dot diameter is substantially enlarged by these two micro dots.

For this reason, when compared with the virtual contour 81 in FIG. 8 (3), the virtual contour 81 in FIG. 7 (2) is less smooth. Therefore, when color printing is performed by overlapping recording of color dots, the effect of preventing jaggedness in the result of printing oblique lines is small even if microdots are added to the outline. Accordingly, it is an object of the present invention to provide a multicolor printing apparatus capable of preventing jaggedness in oblique line printing when performing multicolor printing by overlapping recording of color dots.

[0012]

According to the present invention, for each of a plurality of dots constituting a character or a figure, dots of different colors are superimposed and recorded, and a dot adjacent to the dot located at the outline of the hatched portion of the character or a figure is recorded. Then, when adding a micro dot with a diameter smaller than the diameter of the dot and printing so that the shaded portion becomes smooth, the micro dot is used by using only one of the plurality of recording units. By recording, the image is recorded in one of a plurality of colors to be overlaid.

[0013]

The microdot is not superimposed by a plurality of recording sections, but is one of a plurality of colors to be superimposed by using only one of the plurality of recording sections. Since the recording is performed in the above manner, it is possible to prevent the diameter of the microdot from being enlarged, so that it is possible to obtain a smoother printing of the hatched portion.

[0014]

FIG. 1 shows an example of a multi-color printing apparatus according to the present invention in which a character and a figure are composed of a plurality of dots, and each dot is printed in a desired color by superimposing and recording the dots in a plurality of colors. It is. In FIG. 1, reference numeral 1 denotes a printing unit, which includes recording units 10, 11, 12, and 13 for a plurality of colors.

Reference numeral 2 denotes a control unit, which includes a hatched contour dot detection unit 21 and a print data development unit 22. The hatched outline dot detection unit 21 inputs print data, and outputs characters to be printed,
A dot located at the outline of the oblique line of the figure is detected. Further, data is created by adding a microdot having a smaller diameter than the dot to a portion adjacent to the dot located at the contour portion. The print data developing unit 22 receives the data from the detection unit 21 and creates data for performing printing control on a plurality of printing units corresponding to a plurality of colors in which dots are to be overprinted and a printing unit that prints microdots.

When the printing unit 1 performs printing by electrophotographic recording, the recording units 10, 11, 12, 1
Reference numeral 3 denotes an apparatus for performing electrophotographic recording using toners of different colors. The printing unit 1 further has a fixing device 14 for performing heat fixing after electrophotographic recording.

FIG. 2 shows an embodiment of the oblique line contour dot detecting section 21 in FIG. 1 when the object to be printed is a character. The print data is input in the form of a code, and is composed of a combination of a character code and a print color designation code. 211
Is a pattern memory which outputs a dot pattern corresponding to a character code. 212 is the pattern memory 21
This is a memory that develops and stores a print character string for one line in a dot pattern from a dot pattern output from 1 and a print color designation code. FIG. 3 is an enlarged view of a part of the data developed by the data development unit 212, in which data for one line printing is developed and stored in a dot pattern. R indicates a dot position forming a character recorded in the color red, and G indicates a dot position forming a character recorded in the color green.

Reference numeral 213 in FIG. 2 denotes a comparison unit that compares dot lines. The dot pattern of the one-line print data stored in the data developing unit 212 is sequentially compared between lines, and it is detected that there is a difference between dot lines in a continuous dot group.
Enter 4 In particular, when attention is paid to a plurality of dots forming the oblique lines, the dot groups are shifted between the lines. Therefore, the microdot insertion circuit 214 in FIG. 2 inserts the microdot m based on the difference between the lines of the continuous dot group which is the detection result of the comparison unit 213.

As an example, the following three continuous dot groups are taken as an example.

In this case, a micro dot m is inserted adjacent to R on the right side of the previous dot line. Further, a micro dot m is inserted adjacent to R on the left side of the next dot line row. Therefore, the result of inserting the microdots m is the following dot pattern.

The preceding dot line RRRm the next dot line mRRR The print data developing unit 22 receives the data of the oblique line contour dot detecting unit 21 and stores a control code for controlling each of the recording devices 10, 11, 12, and 13 as developed data. Memory. FIG. 4 is an explanatory diagram of the developed data of the print data developing unit 22 in FIG. 1, and is the developed data corresponding to the portions P and Q of the one-line print data in FIG.

Red R can be recorded by overlapping recording of magenta M and yellow Y. On the other hand, green G can be recorded by overlapping recording of cyan C and yellow Y. Therefore,
At the position of the red R, the control codes M and Y are
The control codes C and Y are stored at the position of. Further, the micro dot m portion is recorded in one of the two colors to be overprinted. In FIG. 4, the microdot m of the portion P is magenta M, and the microdot m of the portion Q is cyan C
To record. Therefore, the control codes M and C are stored, respectively.

In FIG. 1, when the printing unit 1 performs electrophotographic recording, it is the same as the color printing apparatus described with reference to FIG. Recording devices 10, 11, 1
Reference numerals 2 and 13 denote electrophotographic recording devices 62 and 6 in FIG.
3, 64, 65.

Therefore, as shown in FIG.
The control code developed and stored corresponding to the dot pattern in step 2 is sent to the corresponding device of the recording devices 10, 11, 12, 13 or the electrophotographic recording devices 62, 63, 64, 65. In the recording device to which the control code has been sent, the control code is sequentially recorded on the sheet fed by the conveyor belt 61, and the overprinting becomes possible.

FIGS. 5 (1) and 5 (2) are partially enlarged views of the printing results of oblique lines printed according to the present invention. 80-1, 80
-2 indicates dots to be overprinted. Dot 80-
Ideally, 1 and 80-2 are completely overlapped and coincide with each other. However, as described above, the overlap recording is shifted in the direction of the arrow due to difficulties in positioning accuracy due to mechanical conveyance of the sheet. However, in the present invention, the microdots 82-
No. 2 (FIG. 5 (1)) and 82-1 (FIG. 5 (2)) are not overlaid.

In FIG. 5A, the microdot 82-2 is recorded at the same time as the recording of the dot 80-2. FIG.
In (2), the microdot 82-1 is recorded at the same time as the recording of the dot 80-1. In the case of Fig. 5 (2),
The virtual contour 81 of the hatched portion is smoother than that of FIG. However, in both cases of FIG. 5 (1) and FIG. 5 (2), the contour 81 is smoother than that of the conventional method, that is, the contour 81 is smoother than the print result of the shaded portion shown in FIG. It can be seen that prevention or reduction is possible.

The method of recording microdots having a diameter smaller than that of ordinary dots differs depending on the printing apparatus. For example, in the case of a laser printer, the oscillation current of the laser is controlled to change the power of the laser beam. This is easily possible. Ordinary dots may be constituted by a plurality of small dots, and in the case of microdots, may be constituted by several small dots.

Further, in the above embodiment, the microdots 82-1 and 82-2 are recorded in the same color as any one of the dots 80-1 and 80-2. Is not limited. Dots 80-1, 80
-2 with a color different from the color used for recording
It goes without saying that the case of recording -1, 82-2 is also within the scope of the present invention. Further, although the embodiment has been described with respect to two-color overlapping recording, a case of two or more overlapping recordings is also included in the present invention.

[0029]

As described above, according to the present invention,
Even in the case where recording is performed with two or more colors superimposed, the effect of the microdots can be sufficiently utilized, and the recording with high print quality can be performed by preventing the jagged oblique lines.

[Brief description of the drawings]

FIG. 1 shows a schematic diagram of an electrophotographic printing apparatus to which the present invention is applied.

FIG. 2 shows an embodiment of a hatched contour dot detection unit 21 of FIG.

FIG. 3 shows an example of data development by a data development unit for one row in FIG. 2;

FIG. 4 is an explanatory diagram of expanded data by a print data expanding unit 22 of FIG. 1;

FIG. 5 shows a printing example of oblique lines that have been overprinted using microdots according to the present invention.

FIG. 6 is an example of a printing apparatus to which the present invention is applied, and shows an apparatus using electrophotographic recording.

FIG. 7 shows an example of oblique line printing in which overprinting is performed using microdots according to a conventional method.

FIG. 8 shows an example of a case where oblique lines are printed with dots in monochrome printing.

[Explanation of symbols]

Reference Signs List 1 printing unit 2 control unit 10, 11, 12, 13 recording unit 14 fixing unit 21 oblique line contour dot detecting unit 22 print data developing unit 80-1, 80-2 dots 82-1 constituting oblique lines subjected to superimposed recording 82-2 Microdots Attached to Dot Constituting Oblique Line Performed Overlap Printing 81 Virtual Contour Line Dots Connecting Contours of Dot Constituting Oblique Line

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 13/01 G03G 15/01-15/01 117 B41J 2/44 H04N 1/46

Claims (1)

(57) [Claims] 1. A printing apparatus comprising: a plurality of recording units corresponding to a plurality of colors;
Each of the dots constituting a character or a figure has a plurality of recording units.
The different colors are overlap-recorded, and the diameter of the dot is located adjacent to the dot located at the outline of the hatched portion of the character or figure.
Add microdots with a smaller diameter than the
In a multi-color printing apparatus that prints in a manner that is clear, the microdot is one of the plurality of recording units.
One multi-color printing apparatus which is characterized that you record the color of the <br/> plurality of colors to perform the overlapping recording by only recording by the recording unit of.