JPH08281926A - Ink jet printer - Google Patents

Abstract

PURPOSE: To realize a good printing quality without application shifts by setting the dropping amount of ink at a specific value and a distance between a nozzle opening and a recording paper at a specific value. CONSTITUTION: In order to obtain a high clearness (360-1200dpi) while a dot diameter is small, since it is necessary to set the dot diameter to be 30-90μm, the dropping amount of ink is set to be 10-40pl. Moreover, in order to print well, a distance 11 between a nozzle opening 2 and a recording paper is set to be 0.1-1.5mm. Accordingly, a good printing quality without application shifts is achieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer which ejects ink onto paper.

[0002]

2. Description of the Related Art In recent years, ink jet printers using an ink ejecting device have a tendency toward colorization and high image quality, and in order to correspond to high resolution, the dots landed on the recording paper are densified or miniaturized, so that Higher density and smaller amount of ejected ink droplets are required. The conventional inkjet printer will be described below. 3 is a partial sectional view of a conventional inkjet head, and FIG. 4 is a line AA in FIG.
It is sectional drawing. In FIGS. 3 and 4, 2 is a nozzle hole for generating ink droplets, 3 is a nozzle plate forming the nozzle hole 2, 4 is a heater for heating ink, and a wiring portion is not shown, 5 is a heater 4 A substrate for forming ink, 6 is an ink supply hole for supplying ink from an ink tank (not shown), 7 is a flow path for guiding the ink onto the heater 4, and 8 is a flow path 7
Is formed integrally with the substrate 5 by a flow path member that forms
Reference numeral 9 is a voltage applying device for applying a voltage to the heater 4 according to a print signal, 10 is a boiling bubble, 11 is a recording paper, and 12 is an ink droplet. Reference numeral 13 is an adhesive for joining the nozzle plate 3 and the flow path member 8.

FIG. 5 is an assembly diagram of a conventional ink jet head in an ink cartridge. 1 in FIG.
Reference numeral 4 is an ink cartridge equipped with an inkjet head.

FIG. 6 is a partial sectional view of a conventional ink cartridge. In FIG. 6, 15 is an ink cartridge 1.
Ink tank provided in 4 and 16 is ink tank 1
A filter for removing dust contained in the ink in 5.
Reference numeral 7 is an ink introduction groove.

FIG. 7 is an exploded perspective view of an ink jet printer equipped with an ink cartridge 14 incorporating a conventional ink jet head. In FIG. 7, reference numeral 18 denotes a cartridge insertion opening that serves as an entrance when the ink cartridge 14 is attached to the printer, 19 denotes a carriage that fixes the inserted ink cartridge 14, 20 denotes a guide shaft that guides the carriage 19 that reciprocates serially, 21
Is a platen roller for feeding the recording paper 11.

FIG. 8 is a view showing the vicinity of a nozzle hole of a conventional ink jet head. The operation of the inkjet printer configured as described above will be described below. The ink is rapidly heated by the heat generated when the voltage applying device 9 energizes the heater 4, and the boiling bubble 10 is generated. The ink in the flow path 7 is pressured by the boiling bubbles 10 and flows into the nozzle holes 2, and the ink flows out from the nozzle holes 2 to the outside air to form ink droplets 12 due to the surface tension of the ink, and the recording is performed. It adheres to the paper 11. At this time, the distance between the nozzle hole 2 and the recording paper 11 is 2 mm. On the other hand, the bubbling bubble 10 that has been foamed is cooled by the ink and the volume thereof is rapidly reduced. The ink is refilled through the ink supply hole 6 and the flow path 7 due to the negative pressure generated at that time and the surface tension of the ink.

By repeating the above operation, the ink cartridge 14 inserted from the cartridge insertion port 18 and mounted on the carriage 19 reciprocates along the guide shaft 20 in response to a print signal sent from a computer or the like. The voltage application device 9 applies a drive voltage to an arbitrary heater 4 in accordance with the position of the carriage 19, ink droplets 12 are continuously generated and adhere to the recording paper 11 sent by the platen roller 21, and are printed by dots. Is possible.

[0008]

However, if an attempt is made to eject a finer ink droplet 12 with the above-mentioned conventional structure, the ink droplet 12 has a reduced inertial force as shown in FIG. Due to the influence of the viscous resistance of the air received before landing on 11, there is a problem that landing deviation occurs and dot missing occurs without reaching the recording paper 11 and the print quality is impaired.

An object of the present invention is to solve the above problems and to provide an ink jet printer which realizes good print quality without landing deviation.

[0010]

In order to solve the above problems, the present invention sets the amount of ink droplets to 10 to 40 pl and sets the distance between nozzle holes and recording paper to 0.1 to 1.5 mm. To do.

[0011]

With the above-described structure, the present invention can improve landing deviation of ink drops and dot omission due to viscous resistance of air.

[0012]

FIG. 1 is a graph showing the relationship between the amount of ink droplets and the diameter of dots formed on a recording paper in one embodiment of the present invention, based on experimental data. Distance between nozzle hole and recording paper is 1mm, physical property of ink is density 1g / cm, surface tension is 47dyn /
cm, viscosity 1.7 cp, and recording paper used was inkjet paper coated by Nippon Paper Industries Co., Ltd.

FIG. 2 is a graph based on experimental data obtained by measuring the relationship between the nozzle hole, the distance between recording sheets, and the landing deviation for each ink droplet amount in one embodiment of the present invention. The print cycle of the head is 5 kHz, and the moving speed of the head is 212 mm / s. The ejection principle of the head and the operation of the printer are the same as those in the conventional example, and therefore will be omitted.

With respect to the ink jet printer constructed as described above, the relationship between the nozzle hole, the distance between recording sheets, and the landing deviation will be described below. The relationship between the ink droplet amount and the dot diameter formed on the recording paper is as shown in FIG.
High resolution (360dpi ~ 1200d) with smaller dot diameter
In order to obtain pi), the dot diameter needs to be 30 μm to 90 μm, so the ink droplet amount needs to be set to 10 to 40 pl. In the present invention, as shown in FIG.
Within the range of 0 to 40 pl, the landing deviation without landing deviation was set within 10 μm, which is 1/4 of the dot spacing of 42.3 μm in the case of 600 dpi, from the allowable value of overlay in the case of color printing. It was found that the distance between the nozzle hole and the recording paper should be 1.5 mm or less in order to obtain good printing.

In this embodiment, the serial printer which forms characters by reciprocating the head with respect to the recording paper is described. However, the present invention is also effective for a line printer equipped with a line head. Needless to say.

[0016]

As described above, according to the present invention, the viscous resistance of air is controlled by setting the ink droplet volume to 10 to 40 pl and the distance between the nozzle hole and the recording paper from 0.1 to 1.5 mm. It is possible to improve the landing deviation on the recording paper and the dot omission due to the above.

[Brief description of drawings]

FIG. 1 is a graph showing a relationship between an ink drop amount and a dot diameter formed on a recording paper in an embodiment of the present invention, based on experimental data.

FIG. 2 is a graph based on experimental data obtained by measuring the relationship between the nozzle hole, the distance between recording sheets, and the landing deviation according to the ink droplet amount in one embodiment of the present invention.

FIG. 3 is a partial sectional view of a conventional inkjet head.

4 is a line A of the conventional inkjet head shown in FIG.
-A sectional view

FIG. 5 is a diagram of a conventional inkjet head incorporated into an ink cartridge.

FIG. 6 is a partial sectional view of a conventional ink cartridge.

FIG. 7 is an exploded perspective view of an ink jet printer equipped with an ink cartridge incorporating a conventional ink jet head.

FIG. 8 is a diagram showing the vicinity of a nozzle hole of a conventional inkjet head.

[Explanation of symbols]

 2 Nozzle hole 3 Nozzle plate 4 Heater 5 Substrate 6 Ink supply hole 7 Flow path 8 Flow path member 9 Voltage applying device 10 Boiling bubble 11 Recording paper 12 Ink drop 13 Adhesive agent 14 Ink cartridge 15 Ink tank 16 Filter 17 Ink introducing groove 18 Cartridge insertion port 19 Carriage 20 Guide shaft 21 Platen roller

Claims (1)

[Claims] 1. An ink jet printer which prints on a recording paper by ejecting ink droplets from a plurality of nozzle holes provided in a recording head, wherein the amount of ink droplets forming one dot is 10 to 40 pl. An ink jet printer characterized in that a distance between the nozzle hole and the recording paper is 0.1 to 1.5 mm.