JPS58215352A - Image recorder - Google Patents

Abstract

PURPOSE:To obtain an even color image in an ink jet printer by arranging a first recording head block deviated by a specified pitch from the second recording head block in the direction of the ink jetting port array. CONSTITUTION:On a recording head 10, head units 10A and 10B in which four ink jetting orifices 10c are arranged at a specified pitch (a) deviated by a/2 from each other. This one pair of recording heads 10 are arranged in parallel on four carriages and the unit 10A operates in the outgoing direction while the unit 10B in the incoming direction to make a color recording section in four colors of Y, M, C and B. The recording of 8 dots per once is performed in the order of Y-B with unit 10A in the outgoing direction and in the order of B-Y with the unit 10B. In the incoming direction, it is done in the reverse order. Therefore, the difference in the tincture appears only at an interval of 1 dot enabling the recognition of an even color image.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image recording apparatus, and more particularly to an image recording apparatus that records a color image while reciprocating a plurality of recording heads for inks of different colors perpendicular to the paper conveyance direction. .

An example of a color recording device using a multi-head for inks of different colors as described above is an inkjet printer that performs color recording by subtractive color mixing by ejecting ink from an ink jet nozzle and depositing it on the same location on a recording sheet.

Conventional inkjet color recording is performed using yellow, magenta, and cyan (hereinafter referred to as Y), as shown in Figure 1.
Images are recorded by subtractive color mixing using three colors (hereinafter abbreviated as , M, and C), or four colors that are the above three colors plus black (hereinafter abbreviated as B), but the same nozzle is shared by multiple colors. Therefore, four dedicated recording heads 1 for each color are arranged on a carriage 2, and the carriage 2 is moved back and forth in a direction perpendicular to the direction in which the recording paper 3 is conveyed by the platen 4 (indicated by the arrow in the figure). A so-called serial print method for recording images is known. Many of those that perform recording using this method perform recording on both the forward and backward passes in order to increase the recording speed.

This uniform recording device that performs recording both in the forward and backward directions has the following drawbacks. In other words, in Kita's apparatus, recording is performed by horizontally arranging recording heads 1 having a plurality of orifices (spray holes) in one vertical row, so that the ink on the forward and backward passes during recording is as shown in FIG. The ejection order is different (the figure shows an example of a recording head with four ejection holes, in which the order of Y, M, C, B is ejected on the forward pass, and B, C, B on the return pass).
Ink is ejected in the order of M and Y. ), the color development was different depending on the compatibility of the paper and the ink, but the disadvantage was that the color of the finished product would change.

That is, if reciprocating printing is performed using the printing head 1 having a printing width as shown in FIG. 1, color printing will be performed with different colors at every interval as shown in FIG. 2.

This is because in normal inkjet printers, the subtractive color mixing of multiple inks is done on the recording paper, so if the order in which the colors are mixed on the recording paper differs between the forward and return passes, the colors produced by the subtractive color mixture will be different. It is. However, if dot recording is attempted in only one direction in order to solve this problem, the return movement of the head ends up being just movement, resulting in a decrease in the recording speed.

The present invention solves the drawbacks of the conventional devices described above, and aims to provide an image recording device that has a simple structure, can obtain uniform color images, and can operate at high speed. .

In order to achieve the above object, in the present invention, the plurality of recording heads is further constituted by a plurality of head groups each having a receiver for ink of a different color, and the plurality of recording head groups are arranged alternately in the paper conveyance direction. The configuration was adopted.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 3 shows one example of the recording head of the image recording apparatus of the present invention, and here, the recording head 10 has four ink ejection orifices IOC on the surface facing the recording paper at a predetermined pitch a. head units placed apart) IOA
, IQB are arranged parallel to each other by a/2. This pair of head units 10
A and 10B are independent, and the orifice IOC
The rear side opposite to the side with the holder has an ink supply tube, and the receiver can hold recording ink of different colors.

In the image recording apparatus of the present invention, the recording heads 10 described above are arranged on a carriage in the number of required colors to form a recording section. FIG. 4 shows an example in which the above-mentioned recording heads are arranged as a color recording section for four colors of Y, M, and C1B. The color arrangement at this time is, for example, as shown in the upper and lower sides of each recording head. The layout is just reversed.

By performing such an arrangement, the pitch a between the orifices of each head unit IOA and 10B is set to a=2/P (that is, the pitch a between the orifices of each head unit By setting the deviation to a/2=1/P), a desired image density can be obtained. Conversely, the orifice pitch of each head unit 10A and IOB can be configured with twice the pitch if you want to obtain the same image density as the conventional example, making head unit manufacturing much easier. There is also an advantage.

The recording section configured as described above can record eight dots at a time in one line, as shown in FIG.

That is, in the recording operation of the first line (indicated by solid arrows in FIGS. 4 and 5), Y and M are shifted upward, respectively.
, C, H four head units 10A,
10A, IOA, 10A jets ink four times at the same location in the order of Y, M, C, B, and the lower four helad units 1. Ink is ejected in the order of B, C, M, and Y. That is, in the conventional example, a difference in color appears every four dots in the conveyance direction of the recording paper 3, whereas in the present invention, a difference in color appears only every four dots.

The human eye has a condition known as small-area tritanopia, which makes it difficult to judge colors accurately, so it is generally difficult to judge colors accurately when the viewing angle is within lO'. It becomes. For example, you can see printed matter at the clear viewing distance (approximately 30
cm), slight differences in color between lines or points separated by 800p or less are hardly noticeable.

Therefore, as in the present invention, the color of dots that are generally separated by a distance of about one dot is not recognized and is recognized as a uniform color image.

In the embodiment described above, since a configuration is adopted in which the head units each having the same number of orifices are shifted up and down by a predetermined pitch, the dots with the same ejection order are lined up at the boundary between the outward and return trips in FIG. It's gone. In view of this point, an embodiment shown in FIG. 6 can be considered for further completeness.

The recording head 10' shown in FIG. 6 includes a head unit 10A in which four ink ejection orifices IOC are arranged at a predetermined pitch a apart on the surface facing the recording paper, and three ink ejection orifices 10C. It is constructed by arranging two head units 10B, which are arranged at the same pitch and shifted in parallel by a/2. In other words, the recording head 10' has an odd number of ink ejection orifices IOC, one less than the example shown in FIG.

If the recording head configured in this manner is arranged in the same manner as shown in Fig. 4, the ejection order of the lowest dot row on the forward path and the top dot row on the return path will be the same, which will solve the above-mentioned problem. can do.

As is clear from the above description, according to the present invention, the plurality of recording heads is further composed of a plurality of head groups each having a receiver for ink of a different color, and the plurality of recording head groups are arranged alternately in the paper conveyance direction. An image recording device capable of high-speed operation that uses a staggered arrangement to suppress color reversal on a dot-by-dot basis and can obtain uniform color images with a simple structure. can be provided.

[Brief explanation of the drawing]

1 and 2 are for explaining the configuration and operation of a conventional image recording device. FIG. 1 is a perspective view showing a schematic configuration of a conventional image recording device, and FIG. Explanatory diagrams for explaining the operation, FIGS. 3 to 6 are for explaining the configuration and operation of the embodiment of the present invention, and FIG. 3 is a perspective view for explaining the structure of the recording head of the image recording apparatus of the present invention. 4 is a front view illustrating the structure of the recording section of the image recording device of the present invention, FIG. 5 is an explanatory diagram illustrating the operation of the image recording device of the present invention, and FIG. It is a perspective view explaining an example. 3... Recording paper 10... Recording head 10A
, IOB...Head unit IOC...Orifice 21 Procedural amendment (Hitomi May 13, 1980 Dear Commissioner of the Japan Patent Office 1, Display of the case 1982 Patent Application No. 96931 2, Title image of the invention Recording device 3, relationship with the person making the amendment Patent applicant name (100) Canon Co., Ltd. 4, agent Telephone: 03 (268) 2481
(1 Drawing 6, Contents of amendment

Claims (2)

[Claims] (1) In an image recording device that records a color image by arranging a plurality of recording heads that eject ink of different colors and reciprocating in the direction of the arrangement, the inks of different colors are subtracted and mixed on paper, and each color is A first and a second recording head are provided in the recording head, and the first recording head group is arranged to be shifted by a predetermined pitch from the second recording head group in the arrangement direction of the ink ejection ports of each recording head. Image recording device. (2) The first and second recording heads of the first and second recording head groups are arranged alternately.
The image recording device described in .