JPH1086385A - Ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain stable printing quality in which a straight line is not strained even when there is caused a paper skew by arranging a nozzle or an array of nozzles in such a manner that the maximum value of a separated distance in a paper scanning direction of each nozzle forming adjacent dots when printing a straight line substantially normal to the paper scanning direction. SOLUTION: Jet packs 2 each having a plurality of nozzles that are arranged substantially in a row is arranged in a paper scanning direction so as to form together with a frame 3 a printing head 1. Assuming that a space between respective jet packs 2 is α, and a deviation amount relative to the true scanning direction when a paper is advanced a unit distance is β, a nozzle or an array of nozzles are arranged in such a manner that the maximum value of a separated distance in a paper scanning direction of each nozzle forming adjacent dots becomes 2α.β, whereby the nozzle deviation can be limited to 2α.β as maximum to thereby reduce the influence of paper skew, if at all.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an ink jet printer, and more particularly to a nozzle arrangement for improving printing accuracy.

[0002]

2. Description of the Related Art Conventionally, in an ink jet printer having a plurality of nozzles, the nozzles are arranged linearly, and the nozzles are mounted at a high density as the printing resolution increases.

Therefore, when printing at a resolution higher than the nozzle pitch, as shown in FIG. 6, a plurality of nozzle rows formed by a plurality of nozzles are stacked to form a flat nozzle row. Was.

In this case, adjacent nozzles on the image at the time of printing have a certain distance in the feed direction at the time of printing. Therefore, normally, when the paper travels without skew and each nozzle fires ink at a certain timing with respect to the feed speed during printing, it is possible to print a straight line. That is, if the above conditions are not satisfied, straight lines are distorted and printed as shown in FIG.

If the paper is skewed at b with respect to the true scanning direction, and if the distance in the feed direction between adjacent nozzles on the printed image is a, the landing position of the dot is a · b Therefore, the influence of the skew is reduced by reducing a (however, b is constant). However, when the nozzle arrays are combined linearly, nozzle combinations that are distant from each other occur as shown in # 1 and # 12 in FIG. 7, and therefore, as shown in FIG. Extremely affected. When the paper is skewed in this manner, there is a problem that the print quality is extremely lowered such as the occurrence of periodic shading.

[0006]

As described above, the conventional ink jet printer has a problem that the print quality is deteriorated due to the paper skew.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink-jet printer having a stable print quality without a straight line being distorted even when paper skew occurs.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide an ink jet printer which has a plurality of nozzle arrays formed by a plurality of nozzles and forms an image by using the movement of a printing position by running a sheet. On the other hand, this is achieved by arranging the nozzles or nozzle rows such that the maximum value of the separation distance in the paper scanning direction between the nozzles forming adjacent dots when printing a straight line substantially perpendicularly is 2α · β (however, The distance between adjacent nozzles in the feed direction during printing is α, and the shift amount β from the true scanning direction when the paper advances by a unit amount is α).

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

In FIG. 1, a print head 1 comprises a jet pack 2 and a frame 3 arranged in the paper scanning direction. The jet pack 2 has a plurality of nozzles arranged substantially in a line.

More specifically, as shown in FIG. 3A, when a horizontal line is printed, a dot adjacent to the right of the dot of the first nozzle (this is denoted by # 12-1) of the jet pack in the twelfth row is used. Is # 10-1, its neighbor is # 8-1, hereafter # 6-1,
# 4-1, # 2-1, # 1-1, # 3-1, # 5-1,
# 7-1, # 9-1, # 11-1, and next to it are #
12-2, and thereafter, printing is performed in a similar manner. When the paper moves in the scanning direction (the paper moves from bottom to top), each nozzle prints with a delay of the displacement of the arrangement position.

For example, when drawing a line (horizontal line) perpendicular to the paper scanning direction, as shown in FIG. 2, the arranged jet packs # 12, # 11, # 10, # 9, # 8, # 7, #
6, # 5, # 4, # 3, # 2, # 1 are printed in this order.
Here, the interval between the jet packs is temporarily set to α (actually, it is possible to control even if the distance between the jet packs is not uniform, but it is assumed to be easy to control and to simplify the calculation of the displacement error). ), When the sheet is advanced by a unit amount and skewed by the shift amount β with respect to the true scanning direction, in the conventional print head, the shift amount of the adjacent nozzle is jet pack 2 # 1 as shown in FIG. And Jet Pack 2 # 1
A nozzle gap of up to 11α / β occurs between the two nozzles,
In this configuration, as shown in FIG. 3A, the displacement of the adjacent nozzle can be suppressed to 2α · β.

FIG. 4 shows a nozzle arrangement of another invention in which one jet pack has two upper and lower nozzle rows, each of which constitutes one unit. In this case, similarly, the nozzle gap is represented by a maximum of 2α · β.

[0014]

The arrangement of the nozzles of the ink jet printer is set so that the maximum value of the separation distance in the paper scanning direction of the nozzles forming adjacent dots when printing a straight line substantially perpendicular to the paper scanning direction takes the minimum value. By arranging the nozzles, the influence of the skew of the paper can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic front view showing a configuration of a print head as an example of the present invention.

FIG. 2 is a schematic diagram showing the order of printing by the print head of FIG. 1;

FIG. 3 is a schematic diagram illustrating the concept of printing.

FIG. 4 is a schematic front view showing a printhead configuration according to another example of the present invention.

FIG. 5 is a schematic diagram showing the order of printing by the print head of FIG. 4;

FIG. 6 is a schematic front view showing the configuration of a conventional print head.

FIG. 7 is a schematic diagram showing the order of printing by the print head of FIG. 6;

[Explanation of symbols]

1 is a print head, 2 is a jet pack, and 3 is a frame.

Claims (2)

[Claims] 1. An ink jet printer which has a plurality of nozzle arrays formed by a plurality of nozzles and forms an image by using a movement of a printing position by running a paper, prints a straight line substantially perpendicular to a paper scanning direction. An ink jet printer (where the nozzles or nozzle rows are arranged such that the maximum value of the separation distance in the paper scanning direction between the nozzles that sometimes form adjacent dots is 2α · β) The distance in the feed direction at the time of printing is α, and the shift amount β with respect to the true scanning direction when the paper advances by a unit amount is). 2. The ink-jet printer according to claim 1, wherein said nozzle array has a two-row, one-unit configuration.