JPH1134360A - Ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance printing speed without sacrifice of print accuracy by arranging a plurality of print heads in the printing direction while shifting each print head sequentially in the printing direction by an amount corresponding to a plurality of intervals of ink nozzle thereby constituting a set of ink jet heads. SOLUTION: A print head 1 comprises a large number of ink nozzles 5 opening linearly in the print window thereof wherein a plurality of print heads, e.g. three print heads 1a-1c, are arranged in the printing direction as a set of an ink jet head A. The print heads 1a-1c are shifted sequentially by one third of the interval L of the ink nozzle 5 in the print width direction. Since a print 3 of the ink jet head A has a dot pitch L2 equal to L1 /3 and the dot pitch in the print width direction is denser as compared with a single print head 1, print accuracy can be enhanced in the print width direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer, and more particularly to an ink jet printer using a large number of ink jet heads.

[0002]

2. Description of the Related Art A conventional ink-jet printer is provided with one print head, and the print head is moved while one print head is opposed to a sheet and one is relatively moved with respect to the other. The ink is ejected from the printer and printed on paper. In general, the print width of this print head is 10
mm, the dot pitch is 120 to 360 DPI (number of nozzles / inch).

[0003] As a conventional method of using such an ink jet printer, as shown in FIG. 1, a print head a is arranged with its width direction directed in the feed direction of a sheet b. The head a is reciprocated in the width direction of the sheet b, and the sheet b is fed by a pulse motor c in accordance with the printing width, or one or two sheets as shown in FIG. A plurality of print heads a are arranged with their width directions oriented in the width direction of the wrapping paper d, and the wrapping paper d is fed in accordance with printing by the print heads a.

[0004]

In the former of the above prior art, after printing in the width direction of the sheet b with a narrow width (for example, 10 mm), the sheet b is fed over this printing width,
Since the printing is zigzag back on the sheet b, the printing speed is not increased at all. Further, if the feed pitch of the sheet b is made fine in order to make the dot pitch fine in the feed direction (print width direction) of the sheet b, the printing speed is further reduced. When the dot pitch is reduced in the moving direction of the print head a, the moving speed of the print head a becomes slow, and the printing speed also becomes slow in this case.

[0005] Further, in the latter of the above-mentioned prior art,
By arranging a plurality of print heads a in the width direction of the wrapping paper d, printing is performed according to the feed of the wrapping paper d over a desired width in the width direction of the wrapping paper d, and printing is performed more efficiently than the former. However, also in this case, if the dot pitch is made fine as in the former case, the feed speed of the wrapping paper d becomes slow and the printing speed becomes slow.

In the above, in order to make the printing dot pitch finer, it is conceivable to make the pitch of the ink nozzles of the print head a smaller so as to make the interval of the dot pitch DPI narrower. Since there is a processing limit, there is a problem that there is a limit in printing accuracy by reducing the dot pitch DPI, and the price becomes expensive.

[0007] Also, by narrowing the ejection cycle of the ink from the print head, it is possible to speed up the feed of the print head a in the printing direction. However, since this ejection cycle has a limit, it is difficult to perform high-density printing. Feed rate cannot be increased.

In the above conventional technique, in the latter case, it is conceivable to increase the print width of one print head a in order to cover the paper width with a small number of heads.
Actually, a printing width of 114 mm is known, but in this case, it is more difficult to solve the technical problem associated with the advancement of the processing accuracy than the printing width of 10 mm, and the price is increased. There is a problem of doing.

The present invention has been made in consideration of the above, and has been made in consideration of a printing width direction, which is an arrangement direction of ink nozzles of a print head, and a printing direction, which is a direction in which the print head moves relative to paper. Inkjet has the advantages of being able to easily achieve high printing accuracy at low cost, increasing the printing speed without lowering the printing accuracy in the printing direction, and being able to perform multicolor printing with high accuracy. It is intended to provide a printer.

[0010]

In order to achieve the above object, a print head according to the present invention comprises a print head 1 having a large number of ink nozzles 5 arranged at predetermined intervals in a print width direction on a paper W. On the other hand, in the ink jet printer which performs the printing 3 on the paper W in accordance with the input signal from the bitmap data 2 by relatively moving in the printing direction, the print head 1 is moved in plural in each printing direction. The print heads 1a, 1b, and 1c are sequentially shifted in the print width direction by a plurality of intervals L of the ink nozzles 5 to form a set of inkjet heads A. Then, a plurality of the ink jet heads A were arranged in the printing direction.

A plurality of ink jet heads A are arranged in the printing direction, and each set of ink jet heads A is a yellow head Y, a magenta head M, a cyan head C, and a black head B. E.

The ink jet printers A are arranged in the width direction of the paper W.

[0013]

[Work] Dot pitch D of inkjet head A
The PI becomes smaller by the number of combinations of the print heads 1 as a unit, and the printing accuracy in the printing direction and the printing width direction is improved. By arranging a plurality of the ink jet heads A in the printing direction, the printing speed can be increased correspondingly.

By arranging a plurality of ink jet heads A in the printing direction and printing different colors on each of them,
Multicolor printing can be performed with high accuracy. Further, by arranging the inkjet printers A in the width direction of the paper W without gaps in the printing width, printing can be performed simultaneously over a wide width of the paper W.

[0015]

FIG. 3 shows a first embodiment of the present invention.
Explanation will be made based on FIG. In the figure, reference numeral 1 denotes a print head, and reference numeral 2 denotes bitmap data for sending print data to the print head 1 to cause the paper W to perform printing 3 of a predetermined pattern (character). This print head 1
As shown in FIG. 4, a large number of ink nozzles 5 are opened in a printing window 4 in a straight line. The length of the print window 4 is about 10 mm as in the conventional case, and the interval L between the ink nozzles 5 is, for example, 360 dpi (2
(5.4 mm / 360 = 0.0705 mm). The print head 1 is generally used conventionally, and may be 120 or 240 DPI. The dot pitch L ₁ of the print 3 printed by the print head 1 is the interval L between the ink nozzles 5.

As shown in FIG. 5, a plurality of, for example, three print heads 1a, 1b,
1c are arranged in the printing direction to form a set of ink jet heads A. At this time, each print head 1
a, 1b, and 1c are sequentially shifted in the print width direction by １ ／ of the interval L between the ink nozzles 5. The dot pitch _{L 2} configuration printing by one ink-jet head A by 3 _L 1/3, and the 3-fold 1080DP ink nozzles 5 of the dot pitch one printhead 1
I, the dot pitch in the print width direction becomes denser than that of one print head 1, and the print accuracy in the print width direction is improved. In FIG. 5 showing this embodiment, the print heads 1a, 1b, 1c are arranged by being shifted by L / 3 in the printing width direction. However, since the size of L / 3 is extremely small, each print head 1a, 1b, 1c is printed. The heads 1a, 1b, 1c are arranged without apparent displacement.

In this ink jet head A, the cycle for ejecting ink from each ink nozzle 5 is 10 cycles.
In the case of KHZ, the dot pitch in the printing direction is 0.07
By feeding the paper so as to be 05 mm, the printing speed (paper feeding speed) V ₁ becomes V ₁ = 0.0705 × 10 × 10 ³ × 60/1000 = 42.3 (m / min), and 42. Printing is performed on a sheet fed at a speed of 3 m / min at a dot pitch of 360 DPI in the printing direction.

FIG. 6 shows a second embodiment of the present invention, in which a plurality of sets, for example, three sets of the ink jet heads A ₁ , A ₂ , and A shown in FIG.
₃ are arranged in the printing direction. In this embodiment, as described above, the print 3 printed by each of the inkjet heads A ₁ , A ₂ , A ₃ is 360 × 3 = 108 in the print width direction.
Printing is performed at a dot pitch of 0 DPI.

On the other hand, each of the ink jet heads A ₁ ,
The print timing in the A _{2, A 3,} while feeding the paper by the printing speed _{V 1,} for example, intervals of 360 DPI 1 /
When printing is performed by shifting by 3 (= 0.0235 mm) at a time, printing is performed at a printing density of 360 × 3 = 1080 DPI in the printing direction. Thus, in this embodiment, 42.3 m /
min printing speed, and in both the printing direction and the printing width direction, the dot pitch (3
It is possible to print 1080 DPI which is three times as large as 60 DPI. In the printing direction, the dot pitch is set to 36.
Assuming 0 DPI, the printing speed at this time is three times the printing speed (127 m / min).

In the second embodiment, the distance D between the ink jet heads A ₁ , A ₂ , A ₃ is an integral multiple (D = nd) of the distance d between the print heads 1 in each ink jet head.

FIG. 7 shows a third embodiment of the present invention and shows a case of multicolor printing. In this embodiment, the inkjet head A shown in FIG. 5 is arranged in the printing direction as a yellow head Y, a magenta head M, a cyan head C, and a black head B in a printing direction to form a set of multicolor printing inkjet heads E. Is configured.

In this embodiment, each head Y, M,
For C and B, color printing is performed at a dot pitch of, for example, 1080 DPI by the same operation as that of the first embodiment shown in FIG.

Also in the third embodiment,
As in the second embodiment shown in FIG. 6, a plurality of, for example, three, inkjet printing heads E for multicolor printing may be arranged in the printing direction at a predetermined interval D. In this case, similarly to the second embodiment, the paper feed speed V
Is set to 42.3 m / min, so that the respective colors Y, M, C, and B are 1080D in the printing direction and the printing width direction.
Printing is performed at the dot pitch of PI. At this time, registration of printing by the heads Y, M, C, and B is performed by electrical control.

FIG. 8 shows a fourth embodiment of the present invention, in which printing is performed simultaneously over a wide width of the paper W in the width direction. In this embodiment, three sets of ink jet heads A ₁ , A ₂ , A ₃ shown in FIG. 6 constitute one set of many sets of ink jet heads F ₁ , F ₂ , F _3, and each of these ink jet heads F ₁ , F ₂ , F ₃ ...
Are arranged in a staggered manner in the width direction of the paper W as shown in FIG. At this time, each of the inkjet heads F ₁ , F ₂ ,
The print widths of F ₃ ... Are arranged without gaps in the width direction of the paper W. In this case, the arrangement is not limited to a staggered pattern, and the point is that the print width of each set of print heads may be arranged in the width direction of the paper W without gaps.

[0025]

According to the present invention, a plurality of print heads 1a, 1b, and 1c as a unit are arranged in each printing direction, and the respective print heads 1a, 1c are arranged.
b and 1c are distances L between the ink nozzles 5 of each print head.
The dot pitch DPI in the ink jet printer A can be drastically reduced by shifting the dot width DPI in the ink jet printer A by one part in the printing width direction. Can be easily achieved at low cost.

Further, by arranging a plurality of the ink jet printers A in the printing direction, it is possible to improve the printing accuracy in the printing direction or to increase the printing speed while maintaining the printing accuracy. Further, according to the present invention, the printing accuracy can be improved even in multi-color printing, and the printing speed can be dramatically increased as compared with a conventional printing apparatus of this type. Furthermore, by arranging the inkjet printers A in the width direction of the paper W, a device capable of printing without any gap in the width direction of the paper W can be configured with a small space.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a conventional sheet-sheet ink jet printer.

FIG. 2 is a perspective view showing a conventional winding ink jet printer.

FIG. 3 is a perspective view showing a print head of a general inkjet printer.

FIG. 4 is an explanatory diagram showing a printing surface and printing of a print head.

FIG. 5 is an explanatory diagram showing a printing surface and printing according to the first embodiment of the present invention.

FIG. 6 is an explanatory diagram showing a printing surface and printing according to a second embodiment of the present invention.

FIG. 7 is an explanatory diagram illustrating a printing surface according to a third embodiment of the present invention.

FIG. 8 is an explanatory diagram showing a fourth embodiment of the present invention.

[Explanation of symbols]

1, 1a, 1b, 1c ... print head, 2 ... bit map data, 3 ... printing, 4 ... print window, 5 ... ink _nozzles, A 1, _{A 2,} A 3 _... inkjet head, E ... multicolor ink jet head .

Claims (4)

[Claims] An input from a bitmap data by moving a print head, in which a number of ink nozzles are arranged at predetermined intervals in a print width direction, relative to a paper in a print direction. In an ink jet printer which performs printing 3 on the paper W according to a signal, a plurality of the print heads 1 are arranged in each printing direction, and the respective print heads 1a, 1a,
1b, 1c is a multiple of the interval L between the ink nozzles 5
An ink jet printer characterized in that a set of ink jet heads A is sequentially shifted in the printing width direction. 2. An ink jet printer comprising a plurality of sets of the ink jet head A according to claim 1 arranged in a printing direction. 3. A plurality of sets of the ink jet heads A according to claim 1 are arranged in a printing direction, and each set of the ink jet heads A is a yellow head Y, a magenta head M, a cyan head C, and a black head B. An inkjet head E for multi-color printing. 4. An ink jet printer, wherein the ink jet printers A according to claim 2 are arranged in the width direction of the paper W without a gap of a printing width.