JP2932878B2 - Ink jet recording device - Google Patents

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 an ink jet recording apparatus which performs recording by ejecting ink particles on a perforated film toward a recording medium with heat power.

[0002]

2. Description of the Related Art Conventionally, an ink jet recording apparatus as a non-impact recording method basically uses a nozzle ejection method in which ink droplets are ejected from nozzles to collide with a recording medium to form dots of print characters on the recording medium. Although the nozzle type is often used, the nozzle ejection type is liable to cause nozzle clogging and lacks stability as a recording apparatus. Therefore, as a recording method for eliminating the clogging of the nozzle, a vapor jet printing (Vape) combining a perforated film and a thermal head is used.
r Jet Printing (hereinafter referred to as VJP)
Have been proposed.

[0003] The basic structure of the VJP system is such that ink is impregnated into a perforated film having a large number of micropores formed thereon, the film is taken on a thermal head, and the thermal head is driven. Is rapidly heated, and the ink is caused to fly by the generation of bubbles.

FIGS. 10 to 1 show an example of the VJP system.
It is shown in FIG.

[0005] An endless tape-shaped perforated film 91 made of a polyimide resin runs in the direction of arrow F 'in the vicinity of a recording medium 99 such as paper which is moved upward by a platen 98. In the perforated film 91, 1 constituting a printing character
Many small holes 91a finer than the dots are formed in a mesh shape. The small holes 91a are several tens of μm in diameter and several tens μm in diameter.
It can be opened at m pitches. The perforated film 91, the thermal head 92, and the perforated film 91
An ink supply roller 94 for supplying ink from the ink tank 94a and a guide roller 96 for driving the perforated film 91 by a driving source (not shown) are mounted on the carriage 97. The carriage 97 moves in the film running direction F in the width direction of the recording medium 99. ′ Is moved by a driving source (not shown) in the direction of arrow C ′ opposite to ′. A plurality of heating elements 93 are provided at a predetermined pitch in the width direction of the perforated film 91 on the thermal head 92 which is in contact with the recording medium pair 99 with the perforated film 91 interposed therebetween.

In such a configuration, the thermal head 92 is driven with respect to the perforated film 91 in which ink is supplied to the small holes 91a and is running, and a desired heating element 93 necessary for forming printed characters is formed. When energized, the ink filled in the small holes 91a passing over the energized heat generating element 93 is rapidly heated, flies as ink particles 95 due to the generation of bubbles, and collides with the recording surface of the recording medium 99. Recording. That is, a large number of small holes 91 on the perforated film 91
From a, only the ink corresponding to the dot image can be used for recording. FIG. 12 shows the state of the ink particles 95 flying in one dot in this manner.
A plurality of ink particles 9 which are projected in a mesh from a plurality of small holes 91a
5 (FIG. 7A) is merged into a size corresponding to approximately one dot size on the recording surface (FIG. 7B).

In the VJP system using an endless tape-shaped perforated film as described above, it is necessary to move a recording medium, a perforated film, a thermal head, an ink supply mechanism, and the like. A wide space is required for stable running, which causes problems such as an increase in the size of the recording head and an increase in complexity of the entire film drive system.

As another example of the VJP method for solving the drawbacks of the method using the endless tape-shaped perforated film, there is a method using a disc-shaped perforated film.

Although not shown, a large number of mesh-like small holes similar to those described above are provided on the outer peripheral portion of the disk-shaped film, and the film is driven to rotate around its central axis. The disc-shaped perforated film is arranged between the recording medium and the thermal head so as to be in contact with each other, and is rotated. The printing operation is the same as described above, and the ink filled in the small holes passing over the desired heating element energized by the thermal head flies as ink particles, collides with the recording surface, and prints characters. Form. According to this method, since the rotating disc-shaped perforated film performs the same function as the above-described running endless tape-shaped perforated film, it is possible to reduce the size of the entire film drive system including the perforated film. it can.

[0010]

SUMMARY OF THE INVENTION The above-described conventional VJ
In the P-type ink jet recording apparatus, in both the endless tape-shaped perforated film and the disc-shaped perforated film, small holes related to character printing are formed in a mesh shape smaller than one dot. Since the ink flies from a plurality of small holes passing over the heating element when the heating element is energized regardless of the timing,
The composition state of the ink particles in one dot shown in FIG. 12 is at random, and as a result, a problem such as a variation in print density or a failure to obtain a required print density occurs.

In order to reduce the density variation and increase the print density, it is necessary to reduce the diameter of the small holes formed in the perforated film as much as possible and to form the film at a high density. However, forming micropores at a high density in a perforated film made of a polyimide resin has drawbacks in that it is difficult to process and a problem in terms of strength of the film, and cannot be easily realized. is there.

SUMMARY OF THE INVENTION An object of the present invention is to increase the size of a hole on a perforated film up to the diameter of one dot constituting a printed character in order to solve the above-mentioned conventional drawbacks, thereby making it easier to manufacture and improving printing density. It is an object of the present invention to provide an ink jet recording apparatus which improves the recording quality.

[0013]

An ink jet recording apparatus according to the present invention includes a perforated film having a number of small holes and running close to a recording medium, and supplying ink to the small holes of the perforated film. An ink supply mechanism, a thermal head that contacts the portion of the perforated film to which the ink is supplied, and that ejects the ink particles toward the recording medium through the small holes by heat power, and the perforated film. And a carriage mounted with the ink supply mechanism and the thermal head and opposed to the recording medium and moved along the recording medium by a driving mechanism. The plurality of small holes are arranged in a large number of rows arranged in a straight line in a direction perpendicular to the running direction of the perforated film, and The diameter of each of the small holes is equal to the size of one dot forming a printed character, and the position of the thermal head is synchronized with the position of the heating element of the thermal head at a position corresponding to the row of the small holes on the perforated film. And a row of the small holes forms a group with at least two rows.
The small holes are arranged in a zigzag pattern and the detection element is
Provided in correspondence with each of the rows of the small holes;
The heating element of the head comprises at least two rows;
It is arranged corresponding to the staggered small holes .

Further, in the ink jet recording apparatus of the present invention, the perforated film may be a tape-shaped endless film, or the perforated film may be a disc-shaped and driven to rotate around its central axis. The row of small holes may be radially formed on the outer periphery of the disk at a constant pitch angle with respect to the central axis in the radial direction.

[0015]

[0016]

Next, the present invention will be described with reference to the drawings.

In the present invention, a case where a tape-shaped endless film is used as a perforated film and a case where a disc-shaped film is used are considered, and these two examples will be described below.

FIG. 1 is a perspective view of a first embodiment of the present invention, and FIG. 2 is a front view showing a positional relationship between a perforated film and a thermal head in the first embodiment.

In the first embodiment, an example in which a tape-shaped endless film is used as a perforated film will be described.

That is, as shown in FIG. 1, an endless tape-shaped perforated film 1 is provided so as to run in the direction of arrow F in the vicinity of a recording medium 10 such as paper which is moved upward by a platen 9. The perforated film 1 has a number of small holes (ink filling holes 11). The ink supply roller 4 for supplying the ink from the ink tank 4a to the ink filling hole 11 and the ink particles are ejected toward the recording medium 10 by heat power in contact with the portion of the perforated film 1 where the ink is supplied. A carriage 7 is mounted with a thermal head 2 to be driven, a guide roller 6 for running the perforated film 1 by using a film drive motor 3 as a drive source, and a magnetic mark sensor 8. The carriage 7 is arranged to face the recording medium 10 and is moved in the direction of arrow C along the width direction of the recording medium 10 by a driving source (not shown).

Here, the configuration and mutual relationship between the endless tape-shaped perforated film 1 and the thermal head 2 will be described.
This will be described with reference to FIG.

The number of round ink filling holes 11 formed in the perforated film 1 is approximately equal to the size of one dot constituting a character. For example, when recording at a density of 300 dots / inch, the diameter is about 90
μm, and a mesh-like small hole 91 as described in the prior art.
It is at least several times larger than a. Such an ink filling hole 11 is formed in a straight line in a direction perpendicular to the film running direction F. Similarly, in the thermal head 2, a plurality of heating elements corresponding to one dot size are arranged in a straight line.

In this embodiment, as shown in FIG. 2, the heating elements 201, 202,.
48 are divided into two rows, row A and row B, from the relationship of the dot pitch, and these are arranged in a staggered manner. In this embodiment, one character is 4
.., 248, and row B indicates the heating element 2.
, 247 are formed. Also, the ink filling holes 11 are formed in a staggered manner with the row A 11a and the row B 11b at the same pitch so as to correspond to row A and row B of the heating element, respectively. That is, the ink filling hole 11
The hole position is synchronized with the relative movement speed with respect to the thermal head 2 so that when the head position moves relative to the thermal head 2 by one dot in the direction of the arrow F, the next hole position is located exactly at the heating element. Further, on the perforated film 1, in order to take the timing with the position of the heating element of the thermal head 2,
The magnetic markers 12 and 13 are provided in correspondence with the extension lines of the hole positions of the row A 11a and the row B 11b, respectively, for the row A and the row B.

The perforated film 1 and the thermal head 2 constructed in such a relationship are connected to the carriage 7 described above.
The magnetic mark sensor 8 for detecting the magnetic markers 12 and 13 for synchronizing with the position of the thermal head 2 is mounted near the thermal head 2 on the carriage 7 so that the present embodiment can be used. A print head is configured.

In the operation of this embodiment, the running direction F of the perforated film 1 and the moving direction C of the carriage 7 are reversed. The ink is supplied from the ink supply roller 4 to the ink filling hole 11 of the perforated film 1 which is driven by the film driving motor 3 and is guided by the guide roller 6 and travels in the direction of arrow F. Between the feed speed of the perforated film 1 and the moving speed of the carriage 7, the interval between the rows A and B of the heating elements of the thermal head 2 and the perforated film 1
The speed of the film driving motor 3 and the speed of the carriage driving motor (not shown) are determined while maintaining the relationship of the pitch interval (running direction) between the ink filling holes 11a and 11b.
Further, in this film running state, the magnetic mark sensor 8
When the data for driving the row A heating element to the thermal head 2 is output to the thermal head 2 based on the signal from the magnetic mark sensor 8, the magnetic marker (for row A) 12 on the film coincides with the magnetic marker (for row A) 12 on the film. (For row A) 202, 204,..., 248, the timing is adjusted so that the row A 11a of the ink filling hole 11 is located. The row and magnetic markers (for row B) 13 match, and the heating element (for row B) 20
247 are driven so that the row 11b of the ink filling hole 11 for the row B is driven, and the heating element for the row A or the row B of the thermal head 2 is driven. By driving the heating element, the ink in the corresponding ink filling hole 11 at that time is rapidly heated, and ink of a size equivalent to one dot flies due to the generation of bubbles,
One dot is printed by colliding with the recording surface of the recording medium 10.

As described above, according to the present embodiment, the feeding of the perforated film 1 and the moving speed of the thermal head 2 are completely synchronized, so that a unit corresponding to one dot from the ink filling hole 11 of one dot size is used as a unit. The printed characters can be formed by the flying ink. Therefore, there is no need to process the ink filling hole 11 at a fine and high density as in the prior art, and a sufficient print density can be obtained.

Next, as a second embodiment of the present invention, an example in which a disc-shaped film (hereinafter referred to as a perforated disk) is used as the perforated film will be described.

The perforated disk has a structure that can be replaced by the tape-shaped perforated film described in the first embodiment, and has an endless structure by forming an ink filling hole in the outer peripheral portion and rotating. is there.

FIG. 3 is a perspective view of a second embodiment of the present invention, FIG. 4 is an exploded perspective view of a disk head according to the second embodiment, and FIGS. 5A and 5B are used in this embodiment. It is the figure which shows the front view of the perforated disk and its principal part in enlarged scale.

In the second embodiment, the carriage 2 is opposed to a recording medium 30 such as paper which is moved upward by a platen 29.
The carriage 28 is moved in the arrow C direction along the width direction of the recording medium 30 by a driving source (not shown). A disk head 20 for printing characters on a recording medium 30 is mounted on the carriage 28.

As shown in FIG. 4, the disk head 20 has a perforated disk 21, a step motor 23 for rotating the perforated disk 21, and an ink tank 24
a, an inking roller 24 for supplying ink from a, a thermal head 22 for heating and flying ink for printing characters from small holes on the perforated disk 21, and a perforated disk 21.
A disk position detection sensor 25 for timing the positions of the small holes and the heating elements on the thermal head 22;
It has a housing 26 which has an ink discharge hole 26a at one end and houses all the above-mentioned components together with a cover 27.

As in the case of the perforated film shown in the first embodiment, the thermal head 22 has a plurality of heating elements corresponding to one dot of a character in a zigzag pattern in two rows A and B. Are located. On the other hand, the perforated disk 21 of the present embodiment is as shown in FIG. The ink filling holes 31a for the row A and the ink filling holes 31b for the row B are provided on the entire circumference and correspond to the rows A and B of the heating elements of the thermal head 22.
Are formed in a staggered manner and radially in a straight line in the radial direction while maintaining a constant pitch angle with respect to the center of the perforated disk 21. Further, on the extension of the arrangement of the ink filling holes 31a and 31b, the magnetic markers 32,
33 are provided so as to correspond to each other, and are respectively used for column A and column B.

The perforated disk 21 shown in FIG. 5 shows a case where one character is recorded at a density of 300 dots / inch at 48 dots vertically. Two rows of ink filling holes 31a, 31
b are formed at a pitch of 0.9 ° with respect to each other, and this pitch angle is determined by the resolution of the step motor 23. If a DC servo motor is used as a drive source instead of a step motor, this pitch angle The corners may be free,
It is not limited to 0.9 °. The diameter of the perforated disk is 5
0 mm, but this diameter is determined by the pitch between the ink filling holes 31 located at the innermost periphery,
By setting the arrangement pitch angle of the ink filling holes 31 to be large, the diameter can be made smaller than 50 mm. However, it is necessary to increase the rotational speed of the disk as the arrangement pitch angle of the ink filling holes 31 increases, so the diameter of the perforated disk 21 is determined in consideration of the rotational speed.

The perforated disk 21 and the thermal head 22 having such a structure are incorporated in the disk head 20 as described above, and mounted on the carriage 28 to constitute the print head of this embodiment.

In the operation of the present embodiment, the carriage 28 is moved in the direction of arrow C (FIG. 3) while rotating the perforated disk 21 in the direction of arrow D (FIG. 4). The ink is supplied from the inking roller 24 to the ink filling hole 31 of the perforated disk 21 rotated in the direction of arrow D by the step motor 23. Relationship between the rotation speed of the perforated disk 21 and the moving speed of the carriage 28, the distance between the rows A and B of the heating elements of the thermal head 22, and the pitch distance between the ink filling holes 31a and 31b on the perforated disk 21. And the speed of the step motor 23 and the carriage drive motor (not shown) are determined. Further, in the rotating state of the perforated disk 21, based on the signal from the disk position detection sensor 25, when the data for driving the column A heating element is output to the thermal head 22, the data for the column A of the disk position detection sensor 25 And the magnetic marker (for row A) 32 on the disk coincides, the timing is adjusted so that the ink filling hole 31a for row A comes at the heating element for row A, and the data for driving the heating element for row B is adjusted. On output,
For the row B of the disk position detection sensor 25 and the magnetic marker (B
33), the timing is set such that the ink filling hole 31b for the B row is located at the heating element for the B row, and the heating element for the A row or the B row of the thermal head 22 is driven. I do. By driving the heating element, the ink in the ink filling hole 31 corresponding at that time is rapidly heated, and the ink corresponding to one dot flies due to the generation of the bubble, and jumps out of the ink discharge hole 26a of the housing 26 to form the recording medium 30. Collision with the recording surface causes printing of one dot.

As described above, according to the present embodiment, the ink filling hole of the perforated disk 21 is synchronized with the heating element of the thermal head 22 so that the ink filling hole 31 of the one-dot size is formed. A print character having a high density can be formed by the flight of ink equivalent to one dot, and the perforated disk 21 rotating with the ink filling hole 31 on the outer periphery performs the same operation as running an endless film. Can be simplified and downsized.

The present invention is not limited to the embodiment described above, but can be variously modified.

For example, as shown in FIG. 6, a magnetic mark sensor 52a for reading a magnetic marker for timing the positions of the small holes on the perforated film or perforated disk and the heating elements 53a and 53b of the thermal head. , 52b
Are integrally provided on the thermal head 51, so that the head structure can be further simplified as compared with the conventional case where the magnetic mark sensor is mounted at a position different from the thermal head.

In the above-described embodiment, the shape of the ink filling hole is exemplified as a round shape. However, the ink filling hole may be square as shown in FIG. Can be expected to be further improved.

Further, in the case of a perforated disk, a cartridge type which is detachable and easily replaceable can be used. As shown in FIG. 8, a perforated disk 72 is loaded into a cartridge 71 having an ink discharge material 71 with an ink discharge hole 71a at one end and containing an ink-containing material 73 therein. An attachment 74 having a thermal head and a disk position detection sensor mounted thereon and a motor 75 can be easily mounted on the cartridge 71, and these cartridge units can be detachably mounted on the carriage by one-touch operation. When the ink in the ink-containing material 73 is depleted, the cartridge 71 may be replaced together with the perforated disk 72, and maintenance of the print head unit is facilitated.

In the case of a perforated disk, the thickness of the outermost peripheral portion of the disk may be increased. As shown in FIG. 9, in the perforated disk 81, the outermost peripheral portion 82 is formed to be thicker than the portion 83 provided with the ink filling holes 83a. By doing so, the thermal head 8
4 can prevent the perforated disk 81 from being deformed when pressed in the direction of arrow H.

Also, the arrangement of the ink filling holes on the film and the heating elements of the thermal head described in the above embodiments can be variously modified from a single-row arrangement to a plural-row arrangement. The index of the print density as to how many dots the print character is composed of is dot / inch (hereinafter, DPI).
When the value of I is small, that is, when characters are printed with a coarse density configuration, the arrangement of the ink filling holes and the heating elements may be one row. In the case of a printing density of about 300 DPI as in this embodiment, it is necessary to form a staggered two-row array, and when a fine printing density of 300 DPI or more is required, a staggered three or more rows are required. Can be used.

[0043]

As described above, according to the present invention, the size of the ink filling hole provided on the perforated film is increased to the size of the printed character equivalent to the size of one dot, and the ink filling hole and the thermal head are heated. By taking the means of synchronization so that the parts coincide with each other, it is not necessary to process and provide fine holes at a high density as in the prior art, so that the production becomes easy, and the print density can be increased. This has the effect of reducing the variation in density.

In the case of a disc-shaped perforated film, by rotating the film, an endless film can be achieved with a simple structure, and the print head can be reduced in size and simplified.

[Brief description of the drawings]

FIG. 1 is a perspective view of a first embodiment of the present invention.

FIG. 2 is a front view showing a positional relationship between a perforated film and a thermal head according to the first embodiment of the present invention.

FIG. 3 is a perspective view of a second embodiment of the present invention.

FIG. 4 is an exploded perspective view of a disk head according to a second embodiment of the present invention.

FIGS. 5A and 5B show a perforated disk used in the second embodiment, wherein FIG. 5A is a front view and FIG. 5B is an enlarged view of a main part.

FIG. 6 is a perspective view showing another embodiment of the thermal head.

FIG. 7 is a perspective view showing another embodiment of a perforated film.

FIG. 8 is a perspective view showing an embodiment of a cartridge type perforated film.

FIG. 9 shows another embodiment of a perforated disk, and FIG.
Is a perspective view, and FIG. 2B is a sectional view.

FIG. 10 is a perspective view showing an example of a conventional ink jet recording apparatus.

FIG. 11 is a perspective view showing a perforated film and a thermal head in a conventional example.

FIG. 12 is a diagram illustrating a configuration of ink particles in one dot.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Perforated film 2,22 Thermal head 7,28 Carriage 8 Magnetic mark sensor 10,30 Recording medium 11,31 Ink filling hole 12,13,32,33 Magnetic marker 20 Disk head 21 Perforated disk 25 Disk position detection sensor

Claims (9)

(57) [Claims] 1. A perforated film having a number of small holes and running near a recording medium, an ink supply mechanism for supplying ink to the small holes of the perforated film, and the ink of the perforated film And a thermal head for injecting the ink particles through the small holes toward the recording medium by heat power in contact with the portion where the ink is supplied, the perforated film, the ink supply mechanism, and the thermal head. An ink jet recording apparatus comprising: a carriage that is disposed to face the recording medium and moves along the recording medium by a driving mechanism; wherein the plurality of small holes in the perforated film are in a running direction of the perforated film. Are arranged in a large number of rows arranged in a straight line in a direction perpendicular to the direction, and the diameter of the small hole is the size of one dot constituting a printing character. And equivalent to, the perforated fill
A detection element for the on-time at a position corresponding to a row of small holes synchronize the position of the heating elements of the thermal head is provided, one group in the column of the small holes at least two rows
The small holes are formed in a staggered arrangement and the detection element
Are provided corresponding to each of the rows of the small holes, and
The heating element of the thermal head comprises at least two rows.
In addition , the ink jet recording apparatus is arranged so as to correspond to the staggered small holes . 2. An ink jet recording apparatus according to claim 1, wherein said perforated film is a tape-shaped endless film. 3. The perforated film is disk-shaped and is rotatably driven around its central axis, and the row of small holes has a radius at a constant pitch angle with respect to the central axis on the disk-shaped outer peripheral portion. 2. The structure according to claim 1, wherein the second member is formed radially in the direction.
The ink-jet recording apparatus as described in the above. 4. The disk-shaped perforated film, and the disk
Connected to the central axis of the perforated film in the shape of a circle and driven to rotate
A rotating mechanism and the outer peripheral portion of the disc-shaped perforated film.
The thermal head provided in contact with the ink supply;
Mechanism and sensors for the sensing element, all of which
A housing that houses and has the ink ejection hole;
The carriage that moves with the housing mounted thereon
The ink jet recording apparatus according to claim 3, further comprising: 5. A sensor for reading the detection element is provided with a sensor.
The claim is characterized by being provided integrally with the mulled head.
An ink jet recording apparatus according to any one of claims 1 to 4 . 6. The method according to claim 6, wherein the small holes are round.
An ink jet recording apparatus according to claim 1 . 7. The method according to claim 7, wherein the small holes are square.
An ink jet recording apparatus according to claim 1 . 8. The disk-shaped perforated film is detachable.
Housed in a cartridge, and
4. The method according to claim 3, further comprising:
5. The ink jet recording apparatus according to item 4 . 9. An outermost peripheral portion of the disc-shaped perforated film.
Thickness compared to the thickness of the portion provided with the small holes
Claims 3 and 4 or Claim 8
An ink jet recording apparatus according to any one of the above.