JPH10151735A - Ink jet plotter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the printing speed of an ink jet plotter by using a plurality of ink jet printing heads without requiring the adjustment of the precise printing positions of the printing heads. SOLUTION: A plurality of rows of nozzles 18 of ink jet printing heads are provided and a plurality of nozzle rows are parallelly arranged so that all of the nozzles 18 of the respective nozzle rows are opposed to all of the nozzles 18 corresponding to the adjacent nozzle rows. When the printing heads 2, 4 are moved along a Y-rail in the direction shown by an arrow Y, at first, a line 40 composed of a dot group is printed on paper in an ink emitting amt. half a normal ink emitting amt. by the printing head 2 and, next, a line is printed so as to be superposed on the line 40 in an emitting amt. half a normal ink emitting amt. and a line 42 having a normal thickness is formed. The respective dots of the line 42 become a normal dot size by the twice printing at the same position by the printing heads 2, 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet type print head which reciprocates in a main scanning direction across a sheet while moving the sheet relative to the print head in a sub scanning direction to print on the sheet. The present invention relates to an ink-jet plotter (printer).

[0002]

2. Description of the Related Art In an ink-jet plotter, as shown in FIG. 5, a plurality of ink-jet print heads (2) and (4) are used to shorten the printing time. A method is known in which the mounting position is shifted in the sub-scanning direction to widen the printing width (W) in the main scanning direction (C).

[0003]

In the case of the above-described method of increasing the printing width, the adjustment of the printing position of each print head is very severe, and a slight shift of the printing position deteriorates the printing quality. That is, FIGS. 5B and 2B
As shown in the figure, the print line (L
For 1), the print line (L) by the print head (4)
If 2) is shifted, the shift (D) becomes conspicuous, and the entire straight line is distorted. An object of the present invention is to solve the above problems.

[0004]

In order to achieve the above object, the present invention provides an ink jet type print head in which nozzle rows are arranged at right angles to the main scanning direction, and the print head reciprocates in the main scanning direction. With respect to a print head, a plurality of nozzle rows are provided in an inkjet plotter that relatively moves a recording medium in the sub-scanning direction and performs recording on the recording medium with ink droplets ejected from the nozzles of the nozzle row, A plurality of nozzle rows are arranged in parallel so that all the nozzles of each nozzle row face on the main scanning line with all the corresponding nozzles of the adjacent nozzle row, and one nozzle from each nozzle row is
The amount of ink ejected for each dot is the reciprocal of the total number of nozzle rows with respect to the ink ejection quantity of one regular dot, and the same dot is formed by each nozzle of a plurality of nozzle rows.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail with reference to the embodiments of the present invention shown in the accompanying drawings. In FIG. 3, reference numeral (6) denotes a drum platen of an ink jet plotter (printer), which is rotatably supported by the plotter body. The platen (6)
It is connected to the X-axis motor (8) of the sheet feeding means, and is configured to be controlled intermittently in forward and reverse rotation directions by a controller (10) of a plotter. In FIG. 3, a Y-rail (12) extending in the direction perpendicular to the paper of FIG. 3 is opposed to the platen (6), and a head mounting member (14) is mounted on the Y-rail (12) via a carriage (not shown).
Are movably connected in the Y-axis direction along the Y rail (12).

The carriage is connected to a Y-axis motor (16) of a head driving means via a power transmission means such as a belt, and a Y-rail (1) is controlled by a controller (10).
The print head is controlled to reciprocate in the main scanning direction along 2). (2) and (4) are a pair of ink jet print heads mounted on the head mounting member (14). A plurality of ink discharge nozzles (18) are arranged on each ink discharge surface on a coaxial line. The ink ejection surface faces the surface of the platen (6) at a predetermined interval. The pair of print heads (2) and (4)
As shown in FIG. 1, the ink discharge nozzle rows are arranged perpendicularly to the main scanning direction (Y-axis direction) across the recording medium (20) such as roll paper, and the ink discharge nozzles (18) corresponding to each other are arranged. The print heads (2) and (4) are arranged side by side in the horizontal direction so that the positions coincide on the Y axis.

Reference numeral (22) denotes a pressure roller rotatably supported on the plotter body via a holder, and a plurality of pressure rollers are provided on the Y axis. A plurality of pressure rollers (24) are rotatably arranged coaxially at a position distant from the pressure roller (22). A plurality of spur wheels (26) are rotatably arranged coaxially on the opposite side of the pressure roller (22) with respect to the movement path of the print heads (2) and (4). 26) is configured to be able to lightly contact the surface of the platen (6). The pressure rollers (22) and (24) are pressed against the surface of the platen (6) from above the recording medium (20) to grip the recording medium (20) on the platen (6), and the platen (6) Figure 3 of
The recording medium (20) is configured to be fed in the sub-scanning direction in conjunction with the rotation in the middle and counterclockwise directions.

Reference numeral (28) denotes a blade, which prints the recording medium (20) on the platen (6) with the print head (2).
It is supported by the plotter body so that it can be pressed against the surface of the platen (6) just before the movement path of (4). Next, the operation of the inkjet plotter will be described. The recording data signal from the host computer is sequentially taken into the data buffer (32) via the external interface (30), and the data buffer (3) is read.
In 2), for example, one page of recording data is temporarily stored.

The recording data signal is transmitted to the controller (1).
0), the data is sequentially output from the data buffer (32), the ink discharge signal based on the recording data signal is output from the gate circuit (34) by the clock signal from the timing generation circuit (36), and the ink discharge drive circuit (3
By 8), ink droplets are ejected from the nozzle (18) toward the recording medium (20).

On the other hand, the controller (10) controls the intermittent rotation of the platen (6) based on the recording data signal, and conveys the recording medium (20) in the sub-scanning direction. Further, the controller (10) includes a print head (2) (4)
Is reciprocated in the main scanning direction, and recording is performed on the recording medium (20). In the above recording operation, ink is ejected from the nozzles (18) of the print heads (2) and (4) in a size that is about half the size of regular dots.

As shown in FIG. 1A, when the print heads (2) and (4) move along the Y rail (12) in the arrow direction (Y), first, the print head (2) A line (40) composed of a group of dots is printed with a half of the regular ink ejection amount, and then, as shown in FIG. The lines are superimposed and printed from above the line (40) with a discharge amount of half of the above, and a line (42) having a normal thickness is formed. Each dot of the line (42) shown in FIG. 1 (B) has a regular dot size by printing twice at the same position by the print heads (2) and (4).

In this case, even if there is a shift in printing at the same position by the print heads (2) and (4), as shown in FIG. 2A, all print dots have the same shift (D). ,
This gap is not noticeable. In FIG. 2A, (4)
4) is a dot by the print head (2), and (46) is a dot by the print head (4). Print head (2)
(4) Ink is ejected at approximately half the size of regular dots during printing, so that the ink ejection frequency can be increased, thereby increasing the printing speed on the recording medium (20). I can do it. Moreover, the print head (2)
The line printed by (4) is not distorted and the print quality does not deteriorate.

In this embodiment, two print heads are used. However, the number of print heads is not particularly limited to two, and may be three or more. In this case, the amount of ink ejected from the nozzle is the reciprocal of the number of print heads, so that the ink ejection frequency can be further increased, and the printing speed can be increased. However, there is a limit on the ejection frequency due to the ink characteristics. Also, if a plurality of print heads are integrated or integrally molded without using separate print heads, mechanical position adjustment of each print head can be simplified or unnecessary.

[0014]

Since the present invention is constructed as described above, there is an effect that the printing speed can be improved without necessitating precise printing position adjustment and without deteriorating the printing quality.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of the present invention.

FIG. 2 is an explanatory diagram comparing the present invention and a conventional technique.

FIG. 3 is an explanatory side view schematically showing an inkjet plotter.

FIG. 4 is a block diagram of the device of the present invention.

FIG. 5 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 2 Printhead 4 Printhead 6 Platen 8 X-axis motor 10 Controller 12 Y rail 14 Head mounting member 16 Y-axis motor 18 Nozzle 20 Recording medium 22 Pressure roller 24 Pressure roller 26 Spur wheel 28 Blade 40 Line 42 Line

Claims (1)

[Claims] 1. An ink jet type print head having a nozzle array arranged at right angles to a main scanning direction and reciprocating the printing head in a main scanning direction, while moving a recording medium relative to the printing head in a sub scanning direction. In an ink jet plotter for performing recording on the recording medium by ink droplets ejected from the nozzles of the nozzle row, a plurality of nozzle rows are provided, and all the nozzles of each nozzle row correspond to all the corresponding nozzles of the adjacent nozzle row. A plurality of nozzle rows are arranged in parallel so as to face the nozzles on the main scanning line, and one nozzle is arranged from the nozzle of each nozzle row.
The amount of ink ejected for each dot is the reciprocal of the total number of nozzle rows with respect to the ink ejection quantity of one regular dot, and the same dot is formed by each nozzle of a plurality of nozzle rows. Inkjet plotter.