JPS59187865A - Recording head - Google Patents

Abstract

PURPOSE:To prevent other color ink jet nozzles from being contaminated by black color ink, by arranging a black ink jet nozzle at a position lower than those of other color ink jet nozzles. CONSTITUTION:The black ink jet nozzle 4 is arranged to a color recording head at a position lower than those of other color ink (for example, inks of cyan, magenta and yellow) jet nozzles 1, 2 and 3. When nozzles 1, 2 and 3 are arranged on the same horizontal line on a carriage 5, providing recording minimum dissolution is l, respective interval shall be its integral times, mXl and nXl, and the intervals between the row of three nozzle 1, 2 and 3 and the black color nozzle 4 should preferably be its integral times mXl.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field) The present invention relates to a recording head for a color inkjet recording apparatus, and particularly to a recording head that prevents nozzles from becoming dirty.

(Conventional) In conventional recording heads of this type, each nozzle was arranged horizontally, and ink stains did not occur between the nozzles.

However, in order to improve the recording speed, it is better to arrange each nozzle diagonally or vertically. At this time, there is a risk that ink may inadvertently flow from the upper nozzle to the lower nozzle and cause contamination. In particular, if the lower nozzle has a low density ink such as yellow, and if the ink with a high density such as cyan falls from the upper nozzle, it will inevitably cause fatal stains and deteriorate the recording quality.

(the purpose) The present invention aims to solve the above-mentioned difficulties.

(Example I) FIG. 1 is a diagram showing a recording head according to an example of the present invention, and shows, for example, an arrangement example of inkjet nozzles. In the figure 1,
Reference numeral 2.3 denotes a color recording nozzle to which, for example, amber, magenta, and yellow ink is supplied, and recording is performed by ejecting droplets by driving a piezoelectric element or the like. 4 is a nozzle for discharging black ink.

A carriage 5 carries the nozzles 1 to 4 and runs along the width direction of the recording paper.

The nozzles 1, 2, and 3 on the carriage 5 are arranged horizontally and linearly, and the nozzles 1, 2, and 3 on the carriage 5 are spaced apart from each other by 1·1 or 1·1, where 1 is the minimum recording resolution.

However, m and n are integers, and i = n in some cases. The black nozzle/I/4 is arranged on a line perpendicular to the line connecting the above six nozzles 1, 2, and 3, and the interval therebetween is also assumed to be door l.

Arranged as above, when recording a specific color, for example black, 1.2
．． The droplets ejected from the nozzle B are caused to reach the same point to generate black color by mixing colors, thereby forming black dots B1 on the paper. A black dot B2 is still formed by the black nozzle 4.

As a result, the black recording time using only the black nozzle 4 can be halved at least, and the recording speed can be doubled.

This black dragon) B1. When forming B2, since B1 is formed by a mixture of six colors, its dot diameter is larger than that of the single color dot B2.

FIG. 2 shows an example of solving this problem, in which the diameter of the black nozzle 41 is changed to nozzles 1, 2. It was more jerky than Otsu's caliber. Also, a well-known gradation control method such as setting the driving voltage higher than others may be applied.

With this configuration, black dots B1.

The diameter of B2 can be made almost the same, and the recording quality can be improved.

In FIG. 2, P is also an integer, and p = m == n in some cases. 6 and 4 show still other examples of nozzle arrangement.

On each side above, connect the black nozzle/L/4 to the other nozzle 1°2
．． Since the ink nozzle is disposed below the nozzle 6, even if ink falls unexpectedly from above, it will be noticeable since it is a black nozzle, which is particularly preferable in the case of the example shown in FIG.

Figure 5 is a control block diagram, CG is a character generator, T
C is a timing control circuit that controls the driving of each nozzle 1 to 4.

For example, in the case of the nozzle arrangement shown in FIG. 1, if recording is performed while moving the carriage 5 to the right, the carriage 5 reads the scale 6 for confirming its position and informs the control circuit TC. As a result, the AND gate A
A2
Open the nozzle 2, then move the carriage 5 to m-
After moving by l, AND gate A6 is opened to drive the nozzle. As a result, the black drum (B1) shown in FIG. 1 is formed. The cut-and-gate A4 is also opened at the same time, and the nozzle 4 is also driven, so that a drum B2 is formed. Similar results can be achieved with other nozzle arrangements.

(Embodiment ■) FIG. 6 is a perspective view of still another example of the present invention, in which PP is recording paper, Hl, B2. B3 is an inkjet nozzle, and ink of different colors such as black (B), yellow (■), and magenta (goods) is supplied by an ink supply vibe IP to each inkjet nozzle. C
Pl is a control chip fixed to the printed circuit board PC1, fixed to each of the boards H81 to HS3, etc., and further fixed to the common board K.
are arranged in a staggered manner with respect to each other. It is mounted on a carriage (not shown) on the substrate, and performs recording while moving in both directions of arrow AB.

For example, the inkjet nozzle generates air bubbles selectively in each ink chamber by causing a heater in each ink chamber to generate heat.
In addition to attaching the droplet DP to the paper PP by the force, various other mechanisms such as a piezoelectric element can be used. When the nozzles are arranged in a direction almost perpendicular to the moving direction AB of the carriage in this way, for example, the inadvertent ink DD that falls from the nozzle H6 on the side stains the lower nozzle zH1 and mixes one color, resulting in poor printing quality. This causes a decrease in

Therefore, as described above, if the lower nozzle H1 is colored black and the upper nozzle is colored yellow, etc., the above problem can be solved.

However, it is more preferable to completely avoid ink from the upper nozzle from adhering to the lower nozzle. Therefore, an ink guide path IG is provided to receive and stop the ink DD that has flown down and guide the ink DD to a place where it will not stain the nozzle H1 below.

With such a configuration, it is possible to completely avoid contamination of the lower nozzle, and it is possible to prevent deterioration of recording quality.

Various structures can be set for the ink guide path IG as long as they do not pollute the nozzles below.

Further, this vertical configuration is preferable because bidirectional color mixing recording can be performed without any difference in color tone. That is, if bidirectional color mixing recording is performed in the case of the example in FIG. 1, for example, Y0M-1-C and C0M
Both -1 and Y occur, and a difference in color tone appears depending on the recording direction, but in the case of FIGS. 4 and 6, either one can be unified and the recording quality is improved.

FIG. 7 is a diagram showing a control method that can further prevent staining of the platen PL due to inadvertent ink ejection onto the platen PL.

In other words, when the recording paper PP has not reached the front side of the platen PL, if ink is ejected from the nozzles, the platen PL will become dirty, and when the recording paper PP is loaded afterwards, ink will adhere to the back side of the paper. Resulting in. In order to eliminate this drawback, paper position detecting means such as a light emitting element LP and a light receiving element PS are provided, and the nozzles H1 and H2 are rendered operable in response to the detection results.

Furthermore, the operation order of the nozzles is such that the lower nozzles are made drivable in order from the upper nozzles, so that the nozzles can be operated reliably when mixing colors on the recording paper.

That is, if the upper and lower nozzles are driven at the same time or from above when mixing colors, the area recorded by the upper nozzle cannot be subsequently covered with ink of another color, resulting in wasted paper.

Therefore, as shown in the figure, a one-shot multivibrator O81 activated in response to the output of the light receiving element PS and a one-shot multivibrator 082 activated in response to the falling edge of the one-shot multivibrator O81 are provided, and by sequentially activating these, the AND gate A1. A2 are opened in sequence so that the image information from the control unit CC is first applied to the lower nozzle H1, and then applied to the upper nozzle yvH2.

(Effects) As described above, the present invention can improve recording quality,
Highly preferred.

[Brief explanation of the drawing]

Fig. 1 is a nozzle arrangement diagram of one example of the present invention, Fig. 2.6゜4 is another arrangement diagram, Fig. 5 is a control block diagram, Fig. 6 is a diagram of still another example, and Fig. 7 is the same. It is a control block diagram. 1. Life...Yellow Nozzle 2, H2-1I...Magenta Nozzle #3. H3@...Cyan nozzle 4, H
l... Black nozzle applicant Canon Co., Ltd.) 2nd m 3rd

Claims (1)

[Scope of Claims] In a recording head including a plurality of color inkjet nozzles and a black inkjet nozzle, the black inkjet nozzle is located below one of the color inkjet nozzles. A recording head characterized in that: