JPH02235763A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To use a film continuously for a long period of time by supplying solvent to holes of the film after printing, and diluting high viscosity component, though remaining in the holes, with the solvent. CONSTITUTION:Since a film 23 is immersed in cleanser 15 at the time of stop of an ink jet recorder, ink remaining in the small. holes of the film 23 is diluted and cleaned with the cleanser 15. Thus, ethylene glycol, diethylene glycol, etc. contained in ink are not retained in the film 23 as high viscosity components. Since the cleanser 15 introduced into the holes of the film 23 at the time of printing is supplemented into the ink 13, reduction of solvent due to evaporation of the ink 13 in an ink cassette 14, and particularly reduction of water is supplemented to be continuously stably printed. The evaporation of the ink 13 in the cassette 14 is also prevented by sealing a head cover 25 by a head cap 27 as such as possible, and hence the concentration of the ink 13 in the cassette 14 is always held at suitable value.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to an inkjet recording device.

(Prior Art) Recording methods for printing on paper or the like are classified into impact methods and non-impact methods. Recording devices that use the non-impact method inherently have advantages such as lower noise and can be made smaller than those that use the impact method.

By the way, recording devices that use the non-impact method are further classified into several types, and among these are recording devices that use the inkjet recording method. This inkjet recording device basically forms dots on the recording medium by ejecting ink particles from a nozzle and colliding with the recording medium, and has the special advantage of being able to easily perform color recording. It is equipped with But on the other hand,
The problem was that the nozzle was easily clogged, and it lacked stability as a recording device. Recently, inkjet recording devices have been proposed that can significantly reduce clogging. FIG. 4 schematically shows the main parts of a typical inkjet recording device.

In this inkjet recording apparatus, a film 4 is arranged so as to be close to a recording surface 2 of a recording medium 1 such as paper and run in the direction indicated by a solid arrow 3 in the figure.

This film 4 is provided with a large number of small holes 5 having a pitch of several 10 cm and a diameter of several 10 r ttm J. At a position facing the recording surface 2, each small hole 5 is in contact with the surface opposite to the surface facing the recording surface 2 of the film 4.
An ink supply mechanism, for example an ink supply tray 7, for filling the ink 6 is arranged. Further, a thermal head 8 is arranged at a position ahead of the ink supply shaft 7 with respect to the traveling direction of the film 4 so as to be in contact with a surface of the film 4 opposite to the surface facing the recording surface 2. . The contact surface of the thermal head 8 with the film 4 has a film 4
A large number of heating elements are provided at a predetermined pitch in the width direction. The ink supply rod 7 and the thermal head 8 are operated at a speed slower than the traveling speed of the film 4, for example.
The movement is controlled in the same direction as the running direction. That is, in this recording apparatus, each small hole 5 of the film 4 is filled with ink 6 using an ink supplying shaft 7, and the filled ink 6 is
Heat power is applied to the ink by a thermal head 8 to form bubbles, and the ink particles 9 formed by the bubbles collide with the recording surface 2. Since a plurality of heating elements are attached to the contact surface of the thermal head 8 with the film 4 in the width direction of the film 4, if a desired heating element among these is made to generate heat, the light passes over that heating element. Only the ink 6 filled in the small holes 5 becomes ink particles 9 and collides with the recording surface 2. Therefore, film 4
Only the ink 6 corresponding to the dot image can be used for recording through the small holes 5 provided in the dot image. The thermal head 8 used in this recording device operates in the same way as the thermal head in a known thermal transfer recording device.
Further, the film 4 corresponds to the ink ribbon in the recording apparatus.

In the inkjet recording apparatus configured as described above, the amount of ink present in one film hole is minute, and there is no concern that the solid components contained therein will clog the hole. In addition, in this recording method, multiple film holes correspond to one heating element, so even if one hole is not filled with ink, ink particles from other holes will cause dots to form on the recording paper. Because of this, it is difficult to cause missing dots.

However, since this method uses the ink drop ejection (boiling phenomenon), there is a problem that when the ink becomes difficult to boil, the ink particles become difficult to eject.This point will be explained below.Usually used in inkjet printers. The solvent used in the ink used in inkjet recording devices contains a volatile component with a low viscosity and low boiling point as a main component, and a nonvolatile component with a low saturated vapor pressure as an evaporation inhibitor. As a solvent for
Examples include water and ethylene glycol, or water and diethylene glycol. In this combination, water is the volatile component and ethylene glycol and diethylene glycol are the non-volatile components. Therefore, if ink remains in the film pores, the water component evaporates and only high viscosity components such as ethylene glycol and diethylene glycol remain in the film pores. When a film in such a state is used for recording, the ink may not boil, or even if it boils, the viscosity of the solution is high, making it difficult for bubbles to grow, and ink particles may not be ejected. In the inkjet recording method, the film has countless holes, and it is extremely difficult to remove high viscosity ink from all of them.
In some cases, it was thought that it would be impossible to use film. (Issues to be Solved by the Invention) As described above, in the past, high viscosity components contained in ink remain in the film pores, resulting in the ink in the film pores not boiling or bubbles forming. In view of the above points, the present invention allows the film to continue to be used for a long period of time even if high viscosity components remain in the film pores. The purpose is to provide an inkjet recording device.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a film having a plurality of holes and provided close to a recording medium;
a first supply means for supplying a mixture of a colorant and a solvent to the pores of the film; and applying heat power to the pores of the film;
The inkjet recording apparatus has a thermal head that performs printing by colliding particles of a mixed liquid onto a recording medium, and a second supply means that supplies a solvent to holes in the film after printing.

(Function) As described above, since the solvent is supplied to the pores of the film after printing, even if high viscosity components remain in the pores, they are diluted by this solvent. Therefore, the film can be used continuously for a long period of time.

(Example) The present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing the main parts of an inkjet recording apparatus of the present invention. Note that drawing (a) is during printing operation,
The figure (b) shows the state when the apparatus is stopped. Recording media such as paper 1
1 is fixed to a drum-shaped platen 12, and the platen 12
The printing position in the circumferential direction is determined by the rotational movement of. The ink 13 for printing on this recording medium 11 contains dyes and pigments for expressing arbitrary colors such as black and red, and (water + ethylene glycol) and (water + diethylene glycol). The ink cassette 14 is filled with a solvent. Further, the cleaning liquid 15 made of a component having a lower viscosity than the solvent is supplied to the cleaning liquid cassette 1.
6 is filled. As a component of the cleaning liquid, for example, ink 13
The solvent components are 60% water and 40% diethylene glycol.
In the case of 80% water, about 20% diethylene glycol (
Approximately 5cρ) is desirable, but the components may be exactly the same. These ink cassettes 14 and cleaning liquid cassettes
6 forms the first and second supply means, and the rotating shaft 1
The ink cassette 14, which is the first supply means, is supported so as to be positioned upward in the drawing by the rotation of the lever 18 about the lever 18, and the roller 19 is stopped in a state where it is immersed in the ink 13.

The rollers 19, 20, 21, 22 have rotating shafts in the direction perpendicular to the drawing, and the film 23 whose ends are fixed to the rollers 19, 22 is sequentially wound up as the rollers 19, 20, 21, 22 rotate. It's getting worse. Here, most of the films 23 are wound around the roller 19, and the roller 22 rotates to wind up these films 23. The film 23 is provided with many small holes, and the rollers 19, 2
0, 21. 22 rotates the ink cassette 14.
Ink is supplied to the film 23 carried out from the ink l3. The thermal head 24 is located at the home position here, but when printing starts, it moves in a direction approaching the recording medium 11, and the heat generated by the many heating elements provided on the surface in contact with the film 23 causes the thermal head 24 to move toward the recording medium 11. The ink supplied to the small holes obtains heat power from this heat generation, becomes bubbles, and collides with the recording medium l1 as ink particles to perform printing. The above-mentioned printing device is housed in the head force bar 25, and the head force bar 25 is indicated by the arrow 2.
By moving in the direction 6, printing is performed continuously.

Ru. The cleaning liquid cassette 16 is supported so as to be positioned upward in the drawing by the rotation of the lever 18 about the rotating shaft 17, and the roller 22 is stopped in a state where it is immersed in the cleaning liquid 15. At this time, most of the film 23 is wound around the roller 22.

For an inkjet recording device with such a configuration,
Since the film 23 is immersed in the cleaning liquid 15 when the apparatus is stopped, the ink remaining in the small pores of the film 23 is diluted and cleaned by the cleaning liquid 15. Therefore, ethylene glycol, diethylene glycol, and the like contained in the ink do not remain on the film 23 as high-viscosity components. During the printing operation, the film 23 is immersed in the ink 13 again, but since the cleaning liquid 15 that has entered the small holes of the film 23 is replenished into the ink 13, the solvent is removed by the evaporation of the ink 13 in the ink cassette l4. The decrease in water, especially the decrease in water, is compensated for, resulting in continuous and stable printing. The evaporation of the ink 13 in the ink cassette 14 is also prevented as much as possible by sealing the head force bar 25 with the head cap 27, so that the concentration of the ink 13 in the ink cassette 14 is always maintained at an appropriate value. dripping By doing so, even if a highly viscous component remains in the small pores of the film 23, it is quickly diluted, so the film 23 can be used continuously for a long period of time. According to this embodiment, the film 23 is immersed in the ink 13 and the cleaning liquid 15. By doing this, the ink 13 is completely supplied to the small holes of the film 23 in the ink cassette 14,
On the other hand, it is possible to more reliably prevent high viscosity components from remaining in the cleaning liquid cassette 16. Also, each cassette 14.1
As the rollers 19 and 22 rotate within the container 6, the ink 13 and the cleaning liquid 15 flow. Therefore, the density of the ink 13 within the ink cassette 14 is uniform, resulting in stable printing density. On the other hand, in the cleaning liquid cassette 16, high viscosity components are more effectively removed by this flow. roller 19,2
The rotational movements of 0, 21, and 22 can also be performed in a state where no printing is performed, and in this case, the above-mentioned effect due to the flow becomes even more pronounced.

In the above embodiment, the cleaning liquid 15 used had substantially the same composition as the solvent of the ink 13, but in order to be able to handle even when the film 23 was particularly dirty, an ethyl alcohol solution or an organic solvent was used as the cleaning liquid 15. Good too. Also, the film 23 is immersed in the ink 13 and the cleaning liquid 15.
Any portion of the entire structure in which a small hole is provided is sufficient.

FIGS. 2 and 3 are schematic diagrams showing other embodiments of the present invention. In FIG. 2, a pump 28 is used to supply the cleaning liquid 15 to the cleaning liquid cassette l6. During the printing operation, the cleaning liquid 15 is stored in the cleaning liquid tank 29, and when the apparatus is stopped, the cleaning liquid 15 is supplied to the cleaning liquid cassette l6 by the pump 28 through the pipe 30.

The cleaning liquid tank 29 may be located at a position separate from the cleaning liquid cassette 16. Cleaning liquid 15 is replenished from cleaning liquid tank 2.
You can also do this with 9. In FIG. 3, the cleaning liquid 15 is supplied by a manually operated hand pump 31 using a cylinder mechanism. Cleaning liquid 1 in cleaning liquid cassette 16
5 decreases, the hand pump 31 can supply the necessary amount of cleaning liquid 15.

Of course, mechanisms such as the pump 28 and hand pump 31 may be connected to the ink cassette 14 and the ink 13 may be supplied by these pumps 28 and hand pump 31. With such a mechanism, the pump 28 and hand pump 31
As a result, the ink 13 and the cleaning liquid 15 flow more widely, so that the concentration of the ink 13 is made uniform and the high viscosity components are removed by the cleaning liquid 15 more effectively than in the first embodiment.

〔Effect of the invention〕

As described above, according to the present invention, an inkjet recording device is realized which allows the film to be used continuously for a long period of time even if high viscosity components remain in the film holes.

[Brief explanation of the drawing]

1 to 3 are schematic diagrams showing an inkjet recording device of the present invention, and FIG. 4 is a diagram showing a printing portion of a conventional inkjet recording device. 1l...Recording medium 13...Ink (mixture of colorant and solvent) 14...
- Ink cassette (first supply means) 15...Cleaning liquid (solvent) 16...Cleaning liquid cassette (second supply means) 19,2
0,21.22...Roller 23...Film 24...Thermal head

Claims (4)

[Claims] (1) a film having a plurality of holes and provided close to a recording medium; a first supply means for supplying a mixed liquid of a colorant and a solvent to the holes of the film; a thermal head that applies heat power to the holes and causes particles of the mixed liquid to collide with the recording medium to perform printing; and a second supply means that supplies the solvent to the holes of the film after printing. An inkjet recording device comprising: (2) The ink jet recording apparatus according to claim 1, wherein the solvent supplied by the second supply means has a lower viscosity than the solvent supplied by the first supply means. (3) At least one of the liquid mixture contained in the first supply means and the solvent contained in the second supply means is made to flow within these supply means. The inkjet recording apparatus according to claim 1. (4) The inkjet recording apparatus according to claim 1, wherein the film supplies the first supplying means with the solvent supplied by the second supplying means.