JPH06143560A - Ink jet printer head - Google Patents

Abstract

PURPOSE:To provide an ink jet printer head which continuously guarantees stable printing quality by making a heating temperature of ink charged in ink chambers uniform and making diameters of all print dots to be formed on a recording sheet surface constant. CONSTITUTION:An array 10 of ink jet printer heads comprises an orifice plate 14 having a plurality of orifices 12, a cavity plate 20 for forming ink chambers 16 and ink distributing passage 18, piezoelectric ceramics 22 generating mechanical deformation by applying a pulse voltage to apply pressure to the chambers 16, and columns adjacent to the ceramics 22 to highly displace necessary to discharge ink droplet. It also comprises a back heater plate 30 having a function of a heater for heating the entire array 10 for melting solid ink in the chamber 16.

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 head using a solid ink which is melted by heating.

[0002]

2. Description of the Related Art Conventionally, an array 100 of an ink jet printer head of a type using solid ink has an orifice plate 14 having a plurality of orifices 12 as shown in FIGS. The cavity plate 20 in which grooves for forming the chamber 16 and the ink distribution path 18 are processed, the piezoelectric ceramics 22 driven by the application of a pulse voltage, and the piezoelectric ceramics 22 that holds the piezoelectric ceramics 22 to increase its rigidity and to increase the mechanical deformation. The backing plate 24 has a digit for generating a displacement amount, and a heater 26 that heats the entire array 100 to melt the solid ink in the ink chamber 16.

The cavity plate 20 is sandwiched between the orifice plate 14 and the piezoelectric ceramics 22 to secure the ink chamber 16 and the ink distribution path 18, the backing plate 24 is adjacent to the piezoelectric ceramics 22, and the heater 26 is connected to the backing plate 24. It was adjacent. The respective constituent elements of these arrays 100 were adhered to each other by solder and adhesive.

In the head having such a configuration, the ink supplied into the array 100 from an external ink supply source (not shown) flows through the ink distribution path 18 and each ink chamber 16
To be filled. By applying a pulse voltage to the piezoelectric ceramics 22 during printing, the piezoelectric ceramics 22 is mechanically deformed and a pressure is applied to the ink in the ink chamber 16. Due to this pressure, ink droplets were ejected from the orifice 12 toward the recording paper, and printing was performed.

[0005]

However, the heater 26 that heats the entire array 100 is bonded to the backing plate 24 and the adhesive layer 28, so that the heater 26 and the backing plate 24 are bonded to each other by floating or the like. A defect has occurred. As a result, the heating temperature of the ink filled in each ink chamber 16 from the heater 26 through the backing plate 24 and the piezoelectric ceramics 20 becomes non-uniform, and the viscosity of the solid ink in each ink chamber 16 is made different, which in turn results in Orifice 12 communicating with ink chamber 16
Since the volume of the ink droplets ejected from the nozzles and the velocity of the ink droplets differ from orifice to orifice, the diameter of the printing dots formed on the surface of the recording paper becomes unstable and the printing quality is degraded. Further, the adhesive layer 28 has poor durability against heat and does not have the strength enough to reach the designed set life, so that the heater 26 is partially peeled.

The present invention has been made to solve the above-mentioned problems, and makes the heating temperature of the ink filled in each ink chamber uniform so that all the printing dots formed on the surface of the recording paper. It is an object of the present invention to provide an ink jet printer head that continuously guarantees stable printing quality by making the diameter of the ink uniform.

[0007]

In order to achieve this object, an ink jet printer head of the present invention applies pressure to an ink chamber constituted by an array having a heater for melting solid ink by a piezoelectric ceramics which is an actuator. An on-denmand type inkjet printer head that uses solid ink to print by ejecting ink droplets from the orifice to the surface of paper by this pressure, which is in contact with the piezoelectric ceramics and has a high displacement due to mechanical deformation necessary for ejecting ink droplets. The plate with a girder for generating the ink and the heater for heating the entire array to melt the solid ink in the ink chamber are integrated.

[0008]

In the ink jet printer head of the present invention having the above construction, the plate with the girder for contacting the piezoelectric ceramics to generate a high displacement amount due to mechanical deformation necessary for ejecting ink droplets, and the solid ink in the ink chamber Since the heater that heats the entire array for melting is integrally formed, no adhesion failure such as floating occurs between the heater and the beam plate. Therefore, the temperature of the ink filled in all the ink chambers can be kept uniform, and a constant printing state can be maintained for a long period of time.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The same parts as those of the conventional example are designated by the same reference numerals, and the duplicated description will be omitted.

As shown in FIGS. 1 to 3, an array 10 of an ink jet printer head according to the present embodiment has an orifice plate 14 having a plurality of orifices 12, an ink chamber 16 and an ink distribution path in the same number as the orifices 12. A cavity plate 20 which constitutes 18, a piezoelectric ceramics 22 which is driven by applying a pulse voltage,
From the back heater plate 30 that holds the piezoelectric ceramics 22 and increases the rigidity thereof to generate a large amount of displacement due to mechanical deformation, and that serves to heat the entire array 10 to melt the solid ink in the ink chambers 16. It is configured. All the constituent elements of the array 10 are joined to each other by solder which is relatively less deteriorated by heat.

As shown in FIG. 4, the back heater plate 30 is a plate manufactured by subjecting semiconductor ceramics (PTC) to girder processing, and is made of barium titanate (Ba).
TiO ₃ ) is used. Then, an insulating layer 34 of Al ₂ O ₃ or the like is formed on one surface of the semiconductor ceramic, and a plate having a solder layer 36 formed thereon is subjected to girder processing by a method such as dry etching. The mounting is performed by superposing the back heater plate 30 on the piezoelectric ceramics 22 as shown in FIG. 1 and heating under pressure so that the solder layer 36 is melted and the Ni− formed on the surface of the piezoelectric ceramics 22.
It is performed by a method of joining by flowing out to the electrode pattern portion 32 of Cr. An insulating layer 32 is previously formed on a portion of the back heater plate 30 that is in contact with the electrode pattern 32.
Therefore, there is no fear that the pulse voltage applied to the piezoelectric ceramics 22 leaks and the head malfunctions.

In the head having such a structure, the ink supplied from the external ink supply source (not shown) into the array 10 flows through the ink distribution path 18 and is filled in each ink chamber 16. When a pulse voltage is applied to the piezoelectric ceramics 22 during printing, the piezoelectric ceramics 22 is mechanically deformed, and pressure is applied to the ink in the ink chamber 16. By this pressure, ink droplets are ejected from the orifice 12 toward the surface of the recording paper to perform printing. The back heater plate 30 generates heat by being energized from the outside and heats the entire array 10 at a constant temperature, thereby keeping the ink temperature in the ink chamber 16, that is, the ink viscosity constant.

The solid ink used in this embodiment is a wax ink having a melting point of about 70 ° C., and FIG. 5 shows the relationship between temperature and viscosity in the ink. The entire array 10 is heated to 120 ° C. by the back heater plate 30, and the viscosity of the ink in all the ink chambers 16 is uniformly about 32 cps. Ink viscosity and orifice 1
The relationship between the volumes of the ink droplets ejected from No. 2 is the orifice 12
6 has a diameter of about 50 μm, the volume of ink droplets ejected from the plurality of orifices 12 is uniformly 85 pl.

As is clear from the above description, according to the ink jet printer head of this embodiment, the solid ink in the plurality of ink chambers 16 existing according to the number of the orifices 12 is evenly distributed over a long period of time. Guarantee to keep giving a stable temperature. Then, by maintaining a stable ink temperature, the ink viscosity in each ink chamber 16 is made uniform, and the volume and speed of the ink droplets ejected from each orifice 12 are kept constant. Therefore, the diameter of all print dots on the recording paper will be kept constant,
As a result, there is no unevenness in the print quality on one sheet, and it is possible to maintain the same print quality for a long period of time.

The present invention is not limited to the embodiments described in detail above, and modifications can be made without departing from the spirit of the invention.

[0016]

As is apparent from the above description,
According to the inkjet printer head of the present invention, it is ensured that the solid ink in the plurality of ink chambers existing depending on the number of orifices is uniformly and continuously provided with a stable temperature for a long period of time. Then, by maintaining a stable ink temperature, the ink viscosity in each ink chamber is made uniform, and the volume and speed of ink droplets ejected from each orifice are kept constant. Therefore, the diameters of all print dots on the recording paper surface are kept constant, and as a result, there is no unevenness in print quality on one sheet, and it is possible to maintain the same print quality for a long period of time. .

[Brief description of drawings]

FIG. 1 is a perspective view of an array of an inkjet printer head of this embodiment.

FIG. 2 is a perspective view showing a state where the array is assembled.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4A is a plan view of a back heater plate. (B) is the same side view and the side view which expanded a part thereof.

FIG. 5 is a relationship diagram of temperature and viscosity of wax-based solid ink.

FIG. 6 is a diagram showing the relationship between the viscosity of wax-based solid ink and the volume of ejected ink droplets.

FIG. 7 is a perspective view of an array of a conventional inkjet printer head.

FIG. 8 is a perspective view of a conventional array assembled.

9 is a sectional view taken along line BB of FIG.

[Explanation of symbols]

 10 Array 12 Orifice 16 Ink Chamber 22 Piezoelectric Ceramics 30 Back Heater Plate

Claims (1)

[Claims] 1. A solid ink to be printed by applying pressure to an ink chamber composed of an array having a heater for melting the solid ink by a piezoelectric ceramics which is an actuator, and ejecting an ink drop from an orifice onto a paper surface by this pressure. In an on-denmand type inkjet printer head used, in order to melt the solid ink in the ink chamber, a plate with a girder that is in contact with the piezoelectric ceramics and generates a high displacement amount due to mechanical deformation necessary for ejecting ink droplets An ink jet printer head, characterized in that a heater for heating the entire array is integrated.