JP3770477B2 - Inkjet print head - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet head composed of a plurality of print head modules having the same structure in an ink jet printing apparatus.
[0002]
[Prior art]
2. Description of the Related Art Inkjet printing apparatuses that perform printing of characters, images, and the like by discharging ink from a print head module onto a print medium are widely known. Paper, film, plastic materials, etc. are mainly used for the media of this type of printing device. In particular, the operation noise is lower than other printing methods, and the basic mechanical structure can be configured easily and inexpensively. Widely used for data output applications.
[0003]
There is a line head type as an ink jet printing apparatus, but a line head in which the ink discharge nozzles of the print head module are installed only corresponding to the width direction of the print medium is mounted, and the print head module is single or predetermined in the print medium transport direction. A plurality of printing media are arranged at intervals, and the printing medium is held and conveyed by a conveying means using a method such as air suction or electrostatic adsorption. The line head type has advantages such as high-speed color printing. However, depending on the length of the print medium in the width direction, a print head module that can be handled alone has many problems in terms of reliability and cost. In practice, a line head is configured by combining a plurality of print head modules. The method is used. FIG. 4 shows an example in which a plurality of printhead modules are arranged in a staircase pattern to form a unit that achieves a predetermined resolution, and the units are shifted by a predetermined resolution and arranged in a staggered pattern. FIG. 5 shows how the image deteriorated portion looks when the unit is displaced in this configuration. 4 and 5, 1 is a print head module, 3 is a nozzle, 4 is a frame, 6 is a head module unit, 7 is a head module unit, 8 is a print area by the head module unit 6, and 9 is a head module unit 7. Indicates the print area.
[0004]
[Problems to be solved by the invention]
When a line head is configured by combining a plurality of print head modules, in order to achieve a predetermined resolution, a plurality of print head modules are arranged in steps to form a unit, and the units are arranged in a staggered manner. However, when the units are arranged in a staggered manner, a streak-like image quality degradation portion occurs depending on the alignment accuracy between the units. In addition, since the width of the print unit in the print medium conveyance direction becomes large, the influence of dot landing accuracy and paper conveyance accuracy becomes a problem.
[0005]
The present invention proposes a print head module configuration that can reduce the influence of an image quality degradation portion due to a mounting position shift between units in a line inkjet head configured by combining a plurality of print head modules. is there.
[0006]
[Means for Solving the Problems]
In the present invention, a plurality of nozzles are provided in a row, the nozzle pitch is larger than the printing resolution, and the print head module in which the distance between the nozzles at both ends of the row is smaller than the printing width is shifted stepwise. In the inkjet print head having the arrangement, the reference nozzle at the end of the second print head module is set to the first reference nozzle at the end of the first print head module serving as the reference position. The print head module is arranged by being shifted from the next nozzle adjacent to the reference nozzle at the end of the print head module by the print resolution pitch.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. 1, 2, and 3, the same parts as those in FIGS. 4 and 5 are denoted by the same reference numerals.
[0008]
FIG. 1 is a schematic view showing an embodiment of the line inkjet head of the present invention. In the print head module 1 of the present embodiment, a plurality of ink discharge nozzles 3 are formed in a line, and the nozzle pitch Pn is larger than the print resolution pitch Pp. A plurality of print head modules 1 having the same structure narrower than the print width in the print medium width direction are arranged in a stepped manner so as to obtain a prescribed print resolution pitch Pp by arranging them in the print medium transport direction and the print medium width direction. In order to provide the arrangement, the nozzle at the end of the first print head module 1 is used as the reference nozzle 2, and the reference nozzle 2 at the end of the second print head module 1 is used as the reference of the first print head module 1. The nozzles 2 are arranged so as to be shifted from the nozzles adjacent to the nozzle 2 by the printing resolution pitch Pp. Further, the reference nozzle 2 at the end of the next third print head module 1 is shifted by the print resolution pitch Pp from the next nozzle adjacent to the reference nozzle 2 at the end of the second print head module 1. Similarly, a plurality of print head modules 1 are sequentially arranged. Here, in order to configure the line head, the print head modules 1 arranged in a staircase pattern so as to obtain the specified print resolution Pp as described above are used as one head module unit, and this head module unit is used in the print medium width direction. Arrange as many as possible.
[0009]
Accordingly, the overlap width between the head module units is increased, and the influence of the positional deviation between the units is changed from a partial one to an entire one as shown in FIG. As described above, the partial misalignment makes the image deteriorated portion conspicuous, whereas the overall misalignment makes the image deteriorated portion inconspicuous, so that it is possible to reduce the influence of uneven printing due to the variation in the mounting position. .
[0010]
FIG. 3 is a schematic view showing another embodiment of the line inkjet head of the present invention. In the print head module 1 of the present embodiment, a plurality of ink discharge nozzles 3 are formed in a line, and the nozzle pitch Pn is larger than the print resolution pitch Pp. Also, the mounting portions 5 of the print head module 1 are provided at both ends of the module. A plurality of print head modules 1 having the same structure narrower than the print width in the print medium width direction are arranged in a stepped manner so as to obtain a prescribed print resolution pitch Pp by arranging them in the print medium transport direction and the print medium width direction. In order to provide the arrangement, the nozzle at the end of the first print head module 1 is used as the reference nozzle 2, and the reference nozzle 2 at the end of the second print head module 1 is used as the reference nozzle of the first head module 1. The two adjacent nozzles are shifted from each other by the print resolution pitch Pp. Further, the reference nozzle 2 at the end of the next third print head module 1 is shifted by the print resolution pitch Pp from the next nozzle adjacent to the reference nozzle 2 at the end of the second print head module 1. Similarly, a plurality of head modules 1 are sequentially arranged.
Here, in order to configure the line head, the print head modules 1 arranged in a staircase pattern so as to obtain the prescribed print resolution pitch Pp as described above are used as one head module unit, and this head module unit is used as the print medium width. Arrange as many as the direction.
[0011]
In the case of the present embodiment, the number of head modules arranged in the print medium conveyance direction is one (N + 1) larger than the necessary number N for achieving the predetermined print resolution Pp, whereby the head module unit is arranged as a print medium. The space for the head module mounting portion is secured when arranged in parallel to correspond to the width direction.
[0012]
Therefore, when the overlap width between the head module units is increased, the positional deviation between the units is changed from a partial one to the whole, and the influence of unevenness due to the variation in the mounting position can be reduced. In addition, since each unit can be arranged in parallel to the print medium width direction, the length of the line head in the print medium conveyance direction can be reduced, and it is difficult to be affected by the sheet conveyance accuracy. Furthermore, since the order of printing nozzles becomes random, it is possible to reduce the influence of printing unevenness due to variations in characteristics for each print head and ink discharge nozzle characteristics in the print head module.
[0013]
【The invention's effect】
As described above, the present invention has a large overlap width between the units, and the positional deviation between the units is changed from a partial one to the whole so that the image deterioration portion is not noticeable. The influence can be reduced. Further, since the order of printing nozzles is random, it is possible to reduce the influence of printing unevenness due to variations in characteristics of each print head and ink discharge nozzle characteristics in the print head module.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing an embodiment of an ink jet print head of the present invention.
FIG. 2 is an explanatory view showing an embodiment of the ink jet print head of the present invention.
FIG. 3 is an explanatory view showing another embodiment of the ink jet print head of the present invention.
FIG. 4 is an explanatory diagram of a conventional ink jet print head.
FIG. 5 is an explanatory diagram of a conventional ink jet print head.
[Explanation of symbols]
1 is a print head module, 2 is a reference module, and 3 is a nozzle.

Claims (4)

  A configuration in which a plurality of nozzles are arranged in a row, the nozzle pitch is larger than the printing resolution, and the print head modules in which the distance between the nozzles at both ends of the row is smaller than the print width are arranged in a staircase pattern. In the inkjet print head, the reference nozzle at the end of the second print head module is set to the end of the first print head module with respect to the reference nozzle at the end of the first print head module serving as the reference position. An ink jet print head, wherein the ink jet print head is arranged so as to be shifted by a print resolution pitch from a next nozzle adjacent to a reference nozzle.   A configuration in which a plurality of nozzles are arranged in a row, the nozzle pitch is larger than the printing resolution, and the print head modules whose distance between the nozzles at both ends of the row is smaller than the print width are arranged in a staircase pattern. In the inkjet print head, the reference nozzle at the end of the second print head module is set to the end of the first print head module with respect to the reference nozzle at the end of the first print head module serving as the reference position. An ink jet print head, wherein a plurality of rows are sequentially arranged in the same manner by shifting the print resolution pitch from the next nozzle adjacent to the reference nozzle of the part. With respect to the reference nozzle at the end of the first printhead module serving as the reference position, the reference nozzle at the end of the next second printhead module is used as the reference nozzle at the end of the first printhead module. claim 1 or 2 ink jet print head according to, characterized in that the defined nozzle shifted by nozzles shifted by print resolution pitch from. The printhead module pitch specified print resolution are arrayed stepwise constructed a configuration of one head module unit, any one of claims 1 to 3, characterized in that the head module unit and multiple units arranged The ink jet print head according to item .

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