JPH04355150A - Line type ink jet recording apparatus - Google Patents

Abstract

PURPOSE:To achieve miniaturization and to enhance printing quality. CONSTITUTION:A line ink jet recording apparatus is equipped with the flat ink holding plate 101 reciprocating between a thermal head 103 and a platen, the ink filling orifices 107 for holding ink provided to the ink holding plate 101 in one row along the thermal head 103, an ink supply part 105 equipped with an ink supply opening part 106 supplying ink to the ink filling orifices 107 and an ink holding plate driving mechanism opposing the ink filling orifices 107 to the thermal head at the time of the printing operation of the thermal head 103. The ink supply part 105 is formed in a thin plate shape and arranged at the position coming into contact with the ink holding plate 101 on the side of the ink supply opening part 106 and a cover plate 113 is provided at the fixed position opposed to the ink supply opening part of the ink supply part 105 through the ink holding plate.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus, and more particularly to a line type ink jet recording apparatus which performs recording by ejecting ink particles on an ink carrier toward a recording medium using heat power.

0002

BACKGROUND ART Printers, which are output devices for information devices such as personal computers and word processors, are required to have high speed and high print quality, and for this reason, laser printers are rapidly becoming popular. However, this laser printer includes many optical parts and is expensive due to the large number of these components, so it has not been used in general households. For this reason, thermal transfer printers and the like have become more common in households due to the price, and printing speeds have been limited. In addition, in thermal transfer printers, the ink ribbon is fed regardless of the printed characters, resulting in high running costs.

[0003] For these reasons, inkjet printers have emerged as intermediates between laser printers and thermal transfer printers, and with the establishment of the bubble jet method as one type of inkjet printer, they have recently rapidly entered the market. It's coming.

[0004] Inkjet printers supply ink to fine nozzles arranged in vertical dot rows that make up characters, apply pressure to the ink inside these nozzles from the outside using pressure means, and use this pressure to ink. It is designed to be sprayed.

[0005] Means for pressurizing the ink can be roughly divided into piezoelectric methods and bubble methods. In the former piezoelectric method, a piezoelectric material is attached to a part of the ink flow path as a means of pressurizing the ink, and the volume inside the ink flow path is rapidly changed by the curvature of this piezoelectric material. Generally, the ink is pushed out by the change. In addition, the latter bubble method has a heating source that can rapidly heat a part of the ink in contact with the ink flow path, and by heating the ink with the drive of this heating source, bubbles are generated in the ink. This bubble allows the ink to be pushed out.

[0006] Both methods ultimately apply pressure to the ink, but recently bubble-type inkjet printers have become mainstream because of their relatively simple configuration, and notebook-type inkjet printers have become mainstream. Ultra-compact inkjet printers that are compatible with personal computers and other devices have become commercially available at prices that can be purchased by ordinary households.

[0007]

[Prior Art] Conventionally, inkjet recording apparatuses employing non-impact recording methods include the piezoelectric method as described above,
Basically, dots of printed characters are formed on the recording medium by ejecting ink particles from a nozzle onto the recording medium using a bubble-type pressurizing means for the ink flow path. However, with this method of ejecting ink particles from nozzles, the nozzles tend to become clogged due to dryness of the nozzles, and the recording apparatus lacks stability. Therefore, as a recording method to eliminate this nozzle clogging, paper jet printing (Vapor Jet Pri), which combines a perforated film and a thermal head, has been developed.
A method called VJP (hereinafter referred to as VJP) has been proposed.

The basic structure of the VJP method is as shown in Japanese Patent Laid-Open No. 60-71260, ink is impregnated into a perforated film in which a large number of micropores are formed, and this film is placed on a thermal head. The device is configured to rapidly heat the ink on the heating element of the thermal head by driving the thermal head, and the bubbles generated in the ink at this time cause the ink to be ejected.

FIG. 8 shows an example of the conventional VJP method, in which an endless tape-like perforated film 503 made of polyimide resin is placed close to a recording medium 502 such as paper that is moved upward by a platen 501. Travel in the direction of arrow F'. In the perforated film 503, a large number of small holes, which are even finer than one dot constituting a printed character, are formed in a mesh pattern.

FIG. 9 shows the perforated film 503 shown in FIG.
This shows an example of the structure of a small hole 504 with a diameter of several tens of um.
are formed at a pitch of several tens of um.

[0011] Perforated film 503 constructed in this way
travels in the F' direction by a motor, gears, and guide rollers 506 (not shown). Furthermore, this perforated film 5
In the middle of the running system of No. 03, there are an ink supply roller 508 and an ink tank 509 for soaking ink into the small holes formed in the perforated film 503, and a thermal head 510 facing the recording medium 502. The traveling system for the perforated film 503 and the thermal head 510 are mounted on a carriage 511, and are moved in the direction of arrow C', which is opposite to the traveling direction of the perforated film 503, by a drive source (not shown).

In such a configuration, the thermal head 510 is driven against the perforated film 503 which is being supplied with ink by the ink supply roller 508, and the desired image in the thermal head necessary for forming printed characters is generated. When the heat generating element (not shown) is energized, the ink filled in the small hole 504 that was in the heat generating element at the time of energization is rapidly heated, and the ink inside the small hole is heated by bubble generation. is pressurized and ejected as ink particles.

FIGS. 10 to 12 show a perforated film 50.
3 and the thermal head 510 section show the state of ejection of ink particles.
Bubbles 702 are generated in the ink 701 by the energization of the heat generating part 512 of No. 10, and ink particles 513 are ejected by the force of the bubbles. In this manner, the flying ink particles 513 collide with the recording surface of the recording medium 502 to perform recording. That is, the ink filled in the plurality of small holes 504 on the perforated film 503 becomes a plurality of ink particles and flies due to the urging of the thermal head 510. 10 and 11 show approximately 1 on the recording paper surface.
This figure shows the state of one dot merging into a size corresponding to the dot size, and this shape changes in various ways other than those shown in FIG. 10 or 11 depending on the positional relationship between the heating part position 801 of the thermal head and the small hole 504. .

As described above, in the VJP method using a perforated film in the form of an endless tape, it is necessary to move the recording medium, the perforated film, the thermal head, the ink supply, etc., and it is also necessary to move the perforated film stably. This requires a large space, leading to problems such as the recording head becoming larger and the entire film drive system becoming more complex. As another example of the VJP method that eliminates the drawbacks of this endless tape-like perforated film,
No. 222754 There is a method using a disc-shaped perforated film (disk).

Although not shown in the drawings, a large number of small holes similar to those described above are provided on the outer periphery of the disc-shaped film, and the film is rotatably driven around its central axis. This disc-shaped perforated film is placed between the recording medium and the thermal head so that they are in contact with each other, and rotated.

In this case as well, the printing operation is the same as described above, and the ink filled in the small hole passing over the energized desired heating element of the thermal head becomes ink particles and flies, and the recording surface is collide with each other to form printed characters. According to this method, the rotating disc-shaped perforated film performs the same function as the running endless tape-like perforated film described above, so it is possible to downsize the entire film drive system including the perforated film. can.

[0017]

[Problem to be solved by the invention] The above-mentioned conventional VJP
In the inkjet recording device based on this method, the heating element is energized regardless of the timing with respect to the position of the small hole in the perforated film, whether it is an endless tape-like perforated film or a disc-like perforated film. Therefore, in order for ink to be ejected by this bias, the small holes formed in the perforated film must be much finer than the size of one dot that makes up a character, and must be formed in a mesh shape. Furthermore, if these small pores are not formed with a smaller size and higher density, the composition of the ink particles will become at random, resulting in problems such as variations in print density or failure to obtain the desired print density. occurs.

In order to reduce this variation, the small holes formed in the perforated film should be made smaller in size and more densely formed, but the perforated film should be thick enough to hold the ink. However, it is extremely difficult to make holes smaller than the thickness of the perforated film due to processing limitations. Additionally, increasing the density of the pores creates problems with the strength of the portion of film material that remains, e.g.
The limits for this film are a hole diameter of 25 um and a pitch of 45 um.

Therefore, 300DPI (3 in 1 inch)
00 dots), the size of one dot must be about 80 um, and the current perforated film has only 4 to 7 small holes, which energizes the thermal head. Differences in timing result in large variations. Furthermore, when constructing a line type inkjet printer, the perforated film feeding mechanism becomes complicated and large-scale.
It was difficult to realize a line-type inkjet printer.

For this reason, the inventor has developed an ink holder having a row of small holes constituting a character, and a reciprocating mechanism for this ink holder, as shown in FIG.
An inkjet recording device has been proposed that has a thermal head and an ink supply section in contact with this ink holder. What is shown in FIG. 7 is a configuration diagram of a line-type inkjet recording apparatus in which the size of the small hole 402 is set to one dot size constituting a character by reciprocating the ink holder 401. A certain small hole 402 moves back and forth between the line-type thermal head 403 and the ink supply section 404, and when the small hole 402 is at the line-type thermal head position, the line-type thermal head is energized. Not only is the manufacturing problem of 401 solved, but also high printing quality can be obtained because the small holes 402 are one dot in size. However, in this case, due to the positional relationship between the ink supply section and the line-type thermal head, the line-type thermal head is limited to an end-type structure (forming a heat generating part on a plate-like side surface), and this is due to the manufacturing process. In the case of a flat line type thermal head, which is easier to manufacture, the reciprocating displacement of the ink holder must be large due to its relationship with the ink supply section, and measures must be taken to absorb the vibrations of the head itself. This results in another problem. Therefore, if an attempt is made to reduce the displacement of this reciprocating motion, an end-face type thermal head will be required, and it will be extremely difficult to produce a head that can achieve high printing quality such as 400 DPI.

[0021]

OBJECTS OF THE INVENTION The present invention improves the disadvantages of the conventional example, and in particular, reduces the operating range of the ink holder to enable miniaturization and high-speed printing, and at the same time effectively improve printing quality. The purpose is to provide a line type inkjet recording device.

[0022]

SUMMARY OF THE INVENTION The present invention includes a flat ink holding plate that reciprocates between a thermal head and a platen, and an ink holding plate provided on this ink holding body in a line along the thermal head. an ink loading hole, an ink supply section having an ink supply opening for supplying ink to the ink loading hole, and an ink holder drive mechanism that causes the ink loading hole to face the thermal head during printing operation of the thermal head. In the line type inkjet recording device equipped with the above, the ink supply section is formed into a thin plate shape, and
The ink supply section is arranged at a position where the ink supply opening side contacts the ink holding body, and a cover plate is provided at a fixed position facing the ink supply opening of the ink supply section via an ink holding plate. The structure is as follows. This aims to achieve the above-mentioned purpose.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. 1 to 3. FIG. 1 is an exploded perspective view showing the configuration of a line type inkjet recording apparatus according to an embodiment of the present invention. The embodiment shown in FIG. 1 includes a flat ink holding plate 101 that reciprocates between a thermal head 103 and a platen, and an ink holding plate 101 provided in a line along the thermal head on this ink holding body 101. An ink supply unit 105 includes a small hole 107 as an ink loading hole, an ink supply opening 106 that supplies ink to the ink loading hole, and a small hole 107 for loading ink into the thermal head during printing operation of the thermal head. and an ink holder driving mechanism opposed to the ink holder. The ink supply section 105 is formed into a thin plate shape, and is disposed at a position where its ink supply opening side comes into contact with the ink holder 101. Ink supply opening 1 of ink supply section 105
A cover plate 113 is installed at a fixed position opposite to 06 with an ink holding plate 106 interposed therebetween. A thin plate-shaped ink supply section 105 is provided on the thermal head side, and a cover plate 113 is provided on the platen side.

To explain this in more detail, the ink holder 10
Reference numeral 1 indicates a plate shape fixed by support portions 102 at both ends, and this ink holder 101 is configured to reciprocate in the direction of arrow F' by an actuator such as a motor (not shown) and a reciprocating mechanism. Further, there is a line-type thermal head 103 in contact with the plate-shaped ink holder 101, and an ink supply section 105 having an ink inlet flow path 104 located on both sides of the line-type thermal head 103. The position of the opening 106 of the supply section 105 is made to coincide with the position of the small hole 107 forming the dot row forming the characters on the ink holder 101.

Further, the heat generating section 108 of the line type thermal head 103 is in contact with the ink holding body 101 through the hole 109 of the ink supply section 105. In addition, the ink supply section 105 includes a fluid path cover 110 that forms an opening 106 and a fluid path 104 that guides ink to the opening 106.
The fluid path forming plate 111 has an ink introduction port 1.
12 to a fluid path 108 by an ink supply system (not shown).
Fill ink inside.

On the other hand, on the recording paper side of the ink holder 101 opposite to the side in contact with the line-type thermal head 103, there is a cover plate 113 that caps the small holes 107 in the ink holder 101. All of these are combined to form the head.

FIG. 2 shows the relationship between the ink holding body, the ink supply section, and the line type thermal head of the ink jet recording apparatus of the present invention, as seen from the side.
5, the fluid path forming plate is placed on a metal plate with a thickness of 200 um to a depth of 1
The ink flow path 104 is formed by etching a metal plate with a thickness of 50 um, forming a fluid path cover having an opening 106 by etching a metal plate having a thickness of 50 um, and integrating these parts. The opening 106 of this ink supply section 105 is connected to the ink holding body 1.
When 01 is stationary, the cover plate 113 is attached so that it comes to the part of the small hole 107 that is the dot row that makes up the character on the ink holder 101, and the cover plate 113 is placed in the small hole 107.
Capping 7.

Since the ink supply section is thus formed by etching a thin metal plate, the ink holder 101
The distance between the line type thermal head 103 and the line type thermal head 103 is 0.5 mm.
Line type thermal head 10
3 can use a planar type, and the convex heat generating part 201 of the line type thermal head 103 can sufficiently contact the ink holder 101. Further, a convex heat generating portion 201 of the line type thermal head 103 and an opening 10 for filling ink into the ink holder 101 are provided.
6 and the small hole formed in the ink holder 101 itself can be set as small as 3 mm or less.
There is a large degree of freedom in selecting the actuator that performs the reciprocating motion.

By adopting the above structure, when the small hole of the ink holding body is at the open position, the ink small hole is filled by pressure from the ink supply system, and the ink is formed in the ink holding body. The small holes in the ink holder become the heat generating part of the line-type thermal head, so when the line-type thermal head is energized with data that constitutes a character, the ink filled in the small holes in the ink holder is rapidly heated. The ink is pressurized by the generation of bubbles in the ink, and can be ejected as ink droplets. In addition, in this embodiment, in order to prevent the small holes that serve as ink ejection ports from drying out, the small holes of the ink holder remain stationary at the opening of the ink supply section when the printer stops operating, and at the same time The hole is capped with a cover plate.

FIG. 3 is a side view showing the operational relationship between the line type thermal head 103, the ink supply section 105, and the small holes 107 of the ink holder 101 that form the dot array in FIG. The reciprocating motion of 101 is a in the figure.
It moves like →b→c→d→e→f, and returns to state a, and these operations are repeated.

To explain these operations, first, in state a, the small hole 107 formed in the ink holder 101 is located at the opening 106 of the ink supply section 105, and the small hole 107 is filled with ink. ing. Next, by entering the state b, the small hole 107 filled with ink becomes the position of the heat generating part of the line type thermal head 103, and at this time, by energizing the line type thermal head 103, ink droplets are formed as shown in c. 301 and erupts. This is because the ink in the small holes 107 is rapidly heated by the line type thermal head, bubbles are generated in the ink by this heating, and the ink is pushed out by the force of the bubbles.

Next, the ink droplet 301 is ejected and the small hole 107 becomes empty, so that the ink supply section 1 is in the state d.
Ink is supplied from the opening 106 of 05 and filled with ink. Next, the ink holder 101 moves in the direction opposite to b and enters the state e, so that the small hole 107 on the opposite side comes to the position of the heat generating part of the line type thermal head 103. Here, if the thermal head 103 is energized, the result will be as shown in f, and the ink droplets 302 will be ejected due to the pressure caused by the bubbles, as in c. In this way, the state returns to state a again, and the small holes emptied by f are filled with ink again, and by this series of operations, small holes filled with ink are placed alternately at the position of the line type thermal head. Become.

[0033] If these operations are a half-cycle movement of the ink holding body (one cycle in the case of staggered arrangement) and the platen holding the recording paper is fed one dot at a time, one horizontal line of dots forming a character can be moved. Characters are formed on the recording paper by energizing the line-type thermal heads in accordance with the columns.

As is clear from the above description, according to this embodiment, it is possible to construct the ink supply section thinly,
Therefore, a flat line type thermal head can be used, and it can also be applied to a line type thermal head that achieves high printing quality such as 400 DPI. Furthermore, since the interval between the ink supply parts can be reduced to several millimeters or less, the reciprocating mechanism of the ink holder can be driven not only by a motor, but also by using a vibrator such as a piezoelectric material, or an electromagnetic actuator ( Voice coil motor, etc.) can be used.

The present invention is not limited to the embodiments described above, but can be modified in various ways. for example,
The opening of the ink supply section was placed at the position of the small hole forming the dot row when the ink holder was stationary, but this position is limited in any way as long as it is within the maximum amplitude point of reciprocating the small hole. The reciprocating movement of the ink holder, rather than the
This is possible at a position where this small hole passes through the opening of the ink supply section. Furthermore, if you form a circuit for electrode connection on the side of the line-type thermal head that is not on the ink supply side using through-holes or other means, the side of the line-type thermal head on the ink supply side can be configured with only the heat generating part, so you can use this side. For example, a line-type thermal head integrated with the ink holder can be used, eliminating the need for alignment during assembly.

In the above embodiment, the ink supply section is integrated into the upper and lower parts of the line-type thermal head, but the upper and lower parts may be constructed separately.
04 may be combined into one. Furthermore, the shape of the fluid path formed in the ink supply section, the position of the ink introduction port, etc. are not limited in any way, and the material of the ink supply section is not limited to metal either.

[0037]

[Second Embodiment] Next, a second embodiment will be explained based on FIGS. 4 to 6. The second embodiment shown in FIGS. 4 to 6 is characterized in that a thin plate-shaped ink supply section is provided on the platen side, and a cover plate is provided on the thermal head side. In the second embodiment, the ink introduction port 110 of the ink supply section 105 extends beyond the stroke of the ink holder 101, as shown in FIG. Other configurations and operations are the same as those of the first embodiment described above.

Therefore, this second embodiment also has the same functions and effects as the first embodiment described above, and the ink supply unit 105 has a fluid path forming plate formed by forming a fluid path forming plate into a metal plate having a thickness of 200 μm and a depth of 105 μm. The ink flow path 104 is formed by etching, and a fluid path cover having an opening 106 is formed by etching a metal plate having a thickness of 50 μm, and the ink flow path 104 is formed by integrating these. That is, since the ink supply section is formed by etching a thin metal plate, the distance between the ink holder 101 and the line-type thermal head 103 can be kept within 0.5 mm, and the line-type thermal head 103 is A planar type can be used, and the convex heat generating part 201 of the line type thermal head 103 can sufficiently contact the ink holder 101.

[0039]

Effects of the Invention As is clear from the above explanation, the line type inkjet recording device of the present invention has the ability to adjust the size of the ink filling hole (small hole) provided on the ink holder to the size of one dot constituting a printed character. By increasing the size to the same size as the ink filling hole of the parenthesis and taking measures to synchronize the ink filling hole of the bracket and the heat generating part of the line type thermal head to match, it is no longer necessary to machine fine holes with high density as in the conventional method. In addition to the advantages such as being able to increase print density and reduce density variations, the ink supply section is formed thinner, making it easier to manufacture as a line-type thermal head. Easy flat line type thermal heads are now available.
At the same time, the small holes formed in the ink holder are capped with a cover plate, so the ink inside the holes does not dry out, making it possible to create a highly reliable and compact line-type inkjet recording device. can be provided.

Furthermore, since the entire head is composed of a plate-shaped ink holder, this reciprocating mechanism, an ink supply section, and a line-type thermal head, it is no longer necessary to use an endless perforated film as in the past. Since the height of the motor is the highest, even compared to this height, it is possible to make it even more compact than the conventional disk method, and in addition to the effect of making the print head smaller and simpler. Since the distance between the opening of the ink supply section and the heat generating section of the thermal head can be reduced to several millimeters or less, the actuator for reciprocating the ink holder can be not only a motor but also a vibrator such as a piezoelectric element or a voice coil motor. It becomes possible to use actuators such as the following, and the degree of freedom in selecting the actuator becomes high.

[Brief explanation of drawings]

FIG. 1: An exploded perspective view showing a first embodiment of the present invention.

[Figure 2]
A cross-sectional view showing the relationship between the ink supply section, cover plate, and thermal head in FIG. 1

FIG. 3 is an explanatory diagram showing the operation of the ink holder in FIGS. 1 and 2.

[Fig. 4] Exploded perspective view showing the second embodiment

[Fig. 5] A cross-sectional view showing the relationship between the ink supply section, cover plate, and thermal head in Fig. 4.

FIG. 6 is an explanatory diagram showing the operation of the ink holder in FIGS. 4 and 5.

[Figs. 7 and 8] Perspective views showing conventional examples, respectively.

FIG. 9 is an explanatory diagram showing effective films in the conventional example shown in FIG. 8, respectively.

[Figs. 10 to 12] Explanatory diagrams showing the operation of Fig. 8

[Figure 1
3 to 14 are explanatory diagrams showing dots printed by the conventional example of FIG. 8.

[Explanation of symbols]

101 Ink holder 102 Support part 103 Line type thermal head 104 Ink flow path 105 Ink supply section 106 Opening 107 Small hole 108 Fluid path 109 Punch hole 110 Fluid path cover 111 Fluid path forming plate 112 Ink inlet 113 Cover plate 201 Heat generating part 301,302 Ink droplets

Claims (3)

[Claims] 1. A flat ink holding plate that reciprocates between a thermal head and a platen, ink loading holes for holding ink provided in a line along the thermal head in this ink holding body, and an ink supply section including an ink supply opening that supplies ink to the ink loading hole;
In a line-type inkjet recording device comprising an ink holder drive mechanism that causes the ink loading hole to face the thermal head during printing operation of the thermal head, the ink supply section is formed in a thin plate shape, and the ink supply section is formed in a thin plate shape. The ink supply section is arranged at a position where the opening side for the ink comes into contact with the ink holding body, and a cover plate is provided at a fixed position opposite to the ink supply opening of the ink supply section via the ink holding plate. A line-type inkjet recording device that is characterized by: 2. The line type ink jet recording apparatus according to claim 1, wherein the thin plate-shaped ink supply section is provided on the thermal head side, and a cover plate is provided on the platen side. 3. The line type inkjet recording apparatus according to claim 1, wherein the thin plate-shaped ink supply section is provided on the platen side, and the cover plate is provided on the thermal head side.