JPH09216388A - Inkjet color recording device - Google Patents

Abstract

(57) [Summary] (Correction) [PROBLEMS] To prevent a decrease in printing speed due to idle ejection of a recording head for color ink. SOLUTION: Based on the bit map data of the black ink recording head B, the color ink recording heads Y, C,
Among the M nozzle openings, at least a line corresponding to the nozzle opening requiring idle ejection has an idle ejection mode determination means 31 for determining whether there is a region where a dot is formed with black ink, and a printing operation. Without interruption, in addition to the dots corresponding to the print data, when the air-necessary ejection nozzle openings of the color ink recording heads Y, C, and M face the positions where the dots of black ink are formed, The ink jet recording heads Y, C, and M are provided with a second blank ejection control unit 29 for ejecting an ink droplet of a color ink of one color from a required ejection nozzle opening. Ink droplets are ejected from the nozzle openings, and black ink dots based on the print data are overlapped and printed to be hidden by the black dots.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus for printing a pattern on a recording medium by discharging ink droplets from nozzle openings.

[0002]

2. Description of the Related Art An ink jet type recording apparatus uses a recording head which is configured to pressurize ink in a pressure generating chamber by a piezoelectric vibrator or a heating element to discharge ink droplets from nozzle openings. It is necessary to take measures to prevent drying of the ink near the opening and a decrease in print quality due to the adhesion of dust. As one of such measures, the print head is moved to the capping device provided at the standby position in the non-printing area to print data from the nozzle openings every time the printing operation continues for a fixed time, for example, 20 seconds. Irrespective of the operation, so-called flushing operation is performed in which the ink droplets are discharged blank. When ink droplets are ejected regardless of printing in this manner at regular intervals, ink droplets may not be ejected during the printing period, or ink with increased viscosity in the nozzle openings with a small number of ejected ink droplets can be excluded. The time until clogging can be extended.

By the way, an ink jet type color recording apparatus is equipped with two types of recording heads, one for recording black ink for ejecting black ink and the other for recording color ink for ejecting yellow, cyan and magenta inks. Black ink and color ink are supplied to each recording head.

[0004]

Since the black ink and the color ink have different solvents because the data to be printed, the pigments, and the dyes are different, and the drying speeds are different, the flushing of two recording heads is performed. However, a frequent flushing operation is required particularly in color printing in which quick-drying ink is used, and the decrease in printing speed due to the flushing operation becomes a problem. The present invention has been made in view of such a problem, and an object thereof is to improve the speed of color printing by minimizing interruption of printing due to a flushing operation.

[0005]

In order to solve such a problem, according to the present invention, a black ink recording head for ejecting ink droplets of black ink onto a carriage reciprocating in the width direction of a recording medium, and a color A color ink recording head that ejects ink droplets of ink is mounted, the recording head is sealed in a non-printing area, and the ink droplets that are ejected to maintain the ink droplet ejection capability of the recording head during printing. In an ink jet color recording apparatus having a cap member for receiving the above, based on the bit map data of the recording head for black ink, at least nozzle openings of the color recording head that correspond to nozzle openings that require idle ejection are corresponded. A blank discharge mode determination unit that determines whether or not a line has a region where a dot is formed with black ink, and a printing operation. In addition to the dots corresponding to the print data without interruption, the recording for the color ink is performed when the air-necessary ejection nozzle opening of the recording head for the color ink faces the position where the dot of the black ink is formed. The head is provided with an idle ejection control means for ejecting an ink droplet of a color ink of one color from one air ejection nozzle opening of the head.

[0006]

When the blank discharge to the color ink recording head is required, a dot corresponding to the print data and a black ink dot is formed in the blank ink discharge nozzle opening of the color ink recording head. At the time of moving to the position, an ink droplet is ejected from the nozzle opening. Then, the black ink dots based on the print data are overlapped and printed on the color dots formed by the blank ejection, and the color dots formed by the blank ejection are hidden by the black dots.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The details of the present invention will be described below with reference to illustrated embodiments. 1 is a top view showing an embodiment of an ink jet recording apparatus to which the present invention is applied. In the figure, reference numeral 1 is a carriage, one side of which is a timing belt 4 driven by a motor 3 via a coupling tool 2. It is connected and the other side is supported by the guide member 7 of the box body 6 by the sliding piece 5 so that it can reciprocate in the width direction of the recording paper.

A recording head B for black ink for printing text is printed on the non-printing area side of the surface of the carriage 1 facing the recording paper, and yellow, cyan, and magenta inks are discharged on the printing area side. The recording heads Y, C, and M are provided, and the black ink cartridge 8, yellow, and
A color ink cartridge 9 containing cyan and magenta inks is detachably provided.

A platen 10 has a size capable of covering the print area, and a paper feed for conveying recording paper from a paper feed cassette (not shown) to the print area on the back side (upper side in the drawing) of the platen. A roller 11 is provided, and a paper discharge roller 12 that guides a print end area is provided on the front side (lower side in the drawing).

Further, a cap member 13 for sealing the black ink recording head B is provided at a position farthest from the printing region in the non-printing region where the carriage 1 is retracted at rest, and a position closer to the printing region than this is provided. A capping device 15 is configured by providing a cap member 14 that seals the recording heads Y, C, and M for color ink.

FIG. 2 shows an embodiment of a driving device for controlling the printing mechanism. The receiving buffer 20 stores print data from a host (not shown) and the receiving buffer 2.
A bitmap generation means 21 for developing a bitmap image in the print buffer 22 based on the print data of 0;
A carriage control means 23 for moving the recording heads B and Y, C, M to a capping position for reciprocating the carriage 1 for printing operation and flushing, and a recording head B for black ink based on the bit map data. ,
And a first driving unit 24 and a second driving unit 25 that output a driving signal to the color ink recording heads Y, C, and M, the printing time of the black ink recording head B, and the color ink recording heads Y, C, and M. First timing means 2 for timing the printing time of the
6, the second time measuring means 27, and each recording head B, Y, C, based on the time measuring data by the time measuring means 26, 27.
It is composed of first, second and third idle discharge control means 28, 29 and 30 which will be described later and causes M to execute flushing.

The first idle ejection control means 28 interrupts the normal flushing operation for the black ink recording head B, that is, the printing operation when the carriage moves to the capping position after a certain period has passed. Then, the black ink recording head B is moved to a position facing the cap members 14 of the color ink recording heads Y, C, and M, and idle ejection is performed.

The second blank ejection control means 29 performs blank ejection of the color ink recording heads Y, C and M on the basis of a determination result by a blank ejection mode determination means 31, which will be described later, and a black ink dot forming area of a printing area. Is configured to eject a small amount of ink by lowering the level of the drive signal during normal printing, and the third idle ejection control means 30
The recording heads Y, C, and M for color ink are moved to the capping position based on the determination result of the idle ejection mode determination means 31 to perform idle ejection.

Reference numeral 31 denotes the above-mentioned idle discharge mode determination means,
By referring to the bit map data of the black ink recording head B developed in the print buffer 22, at least the nozzle openings of the color ink recording heads Y, C, and M that require idle ejection are supported. It is configured to determine whether or not there is a region where dots are formed with black ink on the line.

Next, the operation of the apparatus thus constructed will be described with reference to FIG.
A description will be given based on the flowchart shown in FIG. When print data is input (step B in FIG. 3), the first and second timing means 26 and 27 start the timing after executing the reset operation. When the print data is expanded into bit map data and printing is performed (step 3 in FIG. 3), each idle discharge control means 28, 29, 30 refers to the time measurement data of the first and second time measurement means 26, 27. Then, the timing of the flushing operation is determined.

When a predetermined amount of printing is performed and an idle ejection operation is required for the black ink recording head B (step C in FIG. 3), the first idle ejection control means 28 causes the recording heads B, Y and C to be ejected. , M, the printing operation of M is interrupted, the black ink recording head B is moved to a position facing the cap member 14 for sealing the color ink recording head, and the black ink recording head B is made to perform idle ejection (FIG. 3 step d).

As a result, it is possible to recover the ink ejection capability of the nozzle openings that did not eject ink droplets during the printing period or the ejection amount was extremely small, and to maintain a constant print quality in the subsequent printing. Become.

Printing is restarted in this way (see FIG. 3).
Step E) This time, the recording head Y for color ink,
When the idle discharge operation for C and M becomes necessary and a signal is output from the second timing means 27 (FIG. 3, step
F), the blank discharge mode determination means 31 is configured to operate the print buffer 22.
Referring to the bit map data of the black ink recording head B developed in the above, the color ink recording heads Y,
It is determined whether or not there is a region in which dots are formed with black ink in the lines corresponding to all the C and M air-necessary discharge nozzle openings (step 3 in FIG. 3).

As a result of the determination, among the nozzle openings of the color ink recording heads Y, C, and M, the lines facing the nozzle openings that did not eject ink droplets at least during the printing period or the ink ejection amount was extremely small. When dots are to be formed with black ink on the upper side, the second blank ejection control unit 29, in addition to the dots corresponding to the print data, the color ink recording head Y, without interrupting the printing. When the C and M air-necessary discharge nozzle openings have moved to the positions where dots of black ink are formed, the level of the drive signal is lowered to reduce the amount of ink droplets from the air-necessary discharge nozzle openings smaller than during printing. Is discharged (step in FIG. 3)
J).

As a result, in addition to the dots corresponding to the print data by the color ink, small dots y, c, m of the small color ink due to the blank ejection are additionally formed (FIG. 4A).

In this manner, the black ink recording head B conforms to the data to be printed with black ink by following the area where the print data is printed by the color ink recording heads Y, C, and M. Black dots b, b,
.. (FIG. 4B), the small color ink dots y, c, m formed by the blank ejection of the color ink recording heads Y, C, M have a relative size of the normal size. Are covered with large black ink dots b, b, b ...

As described above, the color ink recording heads Y,
At the time of blank ejection in the C and M printing areas, the amount of ink is reduced to eject ink droplets to reduce the dot size on the recording paper as much as possible.
It is possible to absorb the positional deviation relative to b, b, ..., And it is possible to perform blank ejection in the printing area without degrading the printing quality. Then, since the idle ejection is executed without interrupting the printing, it is possible to maintain the ink ejection ability of the color ink recording head without causing a decrease in the printing speed.

On the other hand, as a result of the judgment by the blank ejection mode judging means 31, ink droplets are not ejected at least during the printing period among the nozzle openings of the color ink recording heads Y, C, M, or the ejection amount of ink. If there is no plan to form black ink dots on the line facing the nozzle opening, which was extremely small (Fig. 3, step), stop printing and move the recording heads Y, C, M to the capping position. Then, the idle discharge is executed toward the cap member 14 (step D in FIG. 3).

In the above embodiment, for the sake of clarity, the case where the color ink blank ejection regions are aligned in the vertical direction has been described. If it is relatively large, then FIG.
The area to be dispersed is divided into a plurality of blocks (three areas of a rectangle of 6 dots surrounded by a dotted line in the figure) as shown in FIG.
If the blank ejection areas are dispersed so that only one c, m is included, black dots b, b, b based on print data of black ink
It is possible to make the decrease in the density of b ...

FIG. 6 shows a color ink recording head Y,
Another embodiment of the case where the flushing of C and M is performed in the printing area is shown. In this embodiment, the blank discharge mode determination means 31 sets the line corresponding to the required blank discharge nozzle opening of the color recording head. If it is determined that there is an area that forms dots of print data with black ink,
From all of the air-necessary ejection nozzle openings of the color ink recording heads Y, C, and M, blank ejection is performed at positions where black ink dots are formed, and three color ink dots y,
c and m are formed at the same position.

Needless to say, when the three color inks of yellow, magenta and cyan are superposed and printed, so-called composite black is obtained, so that black dots equivalent to black ink can be formed.

Then, dots b made of black ink around
If a large amount of b, b, ... Are formed, that is, black dots are formed using black ink as much as possible in the area that is the edge portion, while only a part of the area surrounded by the black dots is formed. When the black dots are formed by using the composite black by the blank ejection, the blank ejection of the color ink can be performed to the extent that it is almost indistinguishable.

At this time, if the printing operation of the black ink recording head B at the position where the composite black of the three color inks is formed by the first head driving means 24 is interrupted, it is consumed for the blank ejection. Since the color ink used can be effectively used for printing black dots, the running cost can be reduced.

If dots are further formed with black ink at the positions of the composite black dots formed by the blank ejection of the color inks, the blank ejection locations of the color inks can be surely concealed.

Further, in the above-mentioned embodiment, the cartridge is mounted on the carriage, but the ink-jet color of the type in which ink is supplied to the recording head by the tube from the ink tank installed in the box. It is obvious that the same effect can be obtained even when applied to a printer.

[0031]

As described above, according to the present invention, based on the bit map data of the black ink recording head, at least among the nozzle openings of the color ink recording head, the nozzle opening requiring the blank ejection is selected. In addition to the dots corresponding to the print data without interrupting the printing operation, the idle ejection mode determination means for determining whether or not there is a region where a dot is formed with black ink on the corresponding line,
At the time when the air-necessary ejection nozzle opening of the color ink recording head faces the position where a dot of black ink is formed,
1 from the air discharge nozzle opening of the recording head for color ink
Since a blank ejection control unit for ejecting an ink droplet of one color ink is provided at a position, when the blank ejection to the color ink recording head is required, in addition to the dots corresponding to the print data, the color At the position where a black ink dot is formed on the ink jet head of the recording head for ink, a drop of ink is ejected from the nozzle opening, and a black ink dot based on the print data is printed to print black ink. Since it can be hidden by dots, it is not necessary to interrupt printing or move to the capping position, and the printing speed can be improved.

[Brief description of drawings]

FIG. 1 is a top view showing an embodiment of an inkjet color printer to which the present invention is applied.

FIG. 2 is a configuration diagram showing a control means of the same apparatus.

FIG. 3 is a flowchart showing an operation of the above device.

FIG. 4A and FIG. 4B are explanatory diagrams showing a form of idle ejection of a color ink recording head in the same apparatus, respectively.

FIG. 5 is an explanatory diagram showing another example of idle ejection of the recording heads for color ink.

FIG. 6 is a diagram showing another embodiment of the present invention in the form of blank ejection of a recording head for color ink.

[Explanation of symbols]

 1 Carriage 3 Carriage Motor 8, 9 Ink Cartridge 13, 14 Cap Member 15 Capping Device B Black Ink Recording Head Y, C, M Color Ink Recording Head

Claims (8)

[Claims] 1. A black ink recording head that ejects black ink droplets and a color ink recording head that ejects color ink droplets are mounted on a carriage that reciprocates in the width direction of a recording medium. An ink jet color recording apparatus comprising a cap member that seals the recording head in a printing area and receives ink droplets that are ejected to maintain the ink droplet ejection capability of the recording head during printing. Based on the bitmap data of the recording head, it is determined whether or not there is an area where a dot is formed with black ink on a line corresponding to at least a nozzle opening requiring idle ejection among the nozzle openings of the color recording head. In addition to the dot corresponding to the print data without interrupting the printing operation, the blank discharge mode determination means for determining -At the time when the air-necessary ejection nozzle opening of the ink recording head faces the position where a dot of black ink is formed, one color ink of one color ink is placed at one location from the air-necessary ejection nozzle opening of the color ink recording head. An inkjet color recording apparatus comprising: a blank ejection control unit that ejects ink droplets. 2. The ink jet color recording apparatus according to claim 1, wherein the blank ejection control unit controls the ink amount of the color ink recording head during blank ejection to be smaller than the ink amount for normal printing. 3. The blank discharge control means divides a print area of the black ink recording head into blocks, and controls so that ink of each color of the color ink recording head is not included in the same block. The inkjet color recording apparatus according to claim 1. 4. A line corresponding to at least a nozzle opening requiring a blank ejection among the nozzle openings of the color recording head, based on the bit map data of the black ink recording head. 2. The ink jet color recording apparatus according to claim 1, wherein when there is no area for forming dots with black ink, the color ink recording head is moved to the cap member to perform idle ejection. 5. The ink jet color recording apparatus according to claim 4, wherein the blank discharge is performed by a cap member arranged on a side closer to a print area. 6. A black ink recording head for ejecting black ink droplets and a color ink recording head for ejecting color ink droplets are mounted on a carriage that reciprocates in the width direction of a recording medium, An ink jet color recording apparatus comprising a cap member that seals the recording head in a printing area and receives ink droplets that are ejected to maintain the ink droplet ejection capability of the recording head during printing. Based on the bitmap data of the recording head, it is determined whether or not there is an area where a dot is formed with black ink on a line corresponding to at least a nozzle opening requiring idle ejection among the nozzle openings of the color recording head. In addition to the dot corresponding to the print data without interrupting the printing operation, the blank discharge mode determination means for determining -At the time when the air-necessary ejection nozzle opening of the ink recording head faces the position where a dot of black ink is formed, three color inks of three colors are provided at one location from the air-necessary ejection nozzle opening of the color ink recording head. An idle ejection control means for ejecting ink droplets; and a head drive means for stopping ejection of ink droplets from the black ink recording head at a location where dots are formed by idle ejection of the color ink. Inkjet color recording device. 7. The blank discharge of the color ink recording head is prohibited from being formed at an edge boundary of a print area of a black ink dot to be formed by the black ink recording head. Inkjet color recording device. 8. The idle discharge mode determination means corresponds to at least a nozzle opening requiring idle discharge, out of the nozzle openings of the color ink print head, based on the bit map data of the black ink print head. 7. The ink jet recording apparatus according to claim 6, wherein when there is no area for forming dots with black ink in the line, the color ink recording head is moved to the cap member to perform idle ejection.