JPS62173260A - Ink jet printer - Google Patents

Abstract

PURPOSE:To obtain the ink jet printer capable of executing gradation recording without clogging, by setting regions of different densities of ink storing holes or different sizes of holes to an ink storing material. CONSTITUTION:A plurality of regions are established in an ink storage material 1. Though the sizes of ink storage holes 10 are same in those regions (a) and (b) of Figure A, the density of arrangement in the region (a) is higher than that in the region (b). Further, in Figure B, though the densities of arrangement of ink storage holes 10 are same, the size of the storage hole 10 in the region (a) is larger than that of the ink storage hole 11 in the region (b). That is, the ink storing amount per unit area in the ink storing material 1 is different by regions (a) and (b). Therefore, if the region (a) is selected, the recording of high density can be obtained and if the region (b) is selected, the recording of low density can be obtained.

Description

[Detailed description of the invention] [Table of contents] Overview Industrial field of application Conventional technology Problems to be solved by the invention Means for solving the problems (Fig. 1) Working example (a) First Explanation of the embodiment (Fig. 2) (b) Explanation of the second embodiment (Fig. 3) (C) Explanation of the third embodiment (Fig. 4) (d) Explanation of the fourth embodiment ( Fig. 5) (e) Description of other embodiments Effects of the invention [Summary] In an inkjet printer that ejects ink from ink storage holes of an ink container onto a recording medium by driving a thermal head, each ink container is filled with ink. A plurality of areas having different densities or sizes of accommodation holes are provided, and by selecting one of these areas, the amount of ink ejected is changed to perform gradation recording.

[Industrial application field]

The present invention relates to an inkjet printer that performs recording by bringing an ink container having a large number of ink storage holes into contact with a thermal head and ejecting ink from the ink storage holes by driving the thermal head.

In particular, it relates to an inkjet printer capable of expressing gradations.

Inkjet printers, which perform recording by ejecting ink, have advantages such as being a direct recording method and being able to perform noiseless recording, and are considered promising as printers.

However, it is technically difficult to control ink clogging and ink particles9, so it has not become as popular as expected.

[Conventional technology]

As a solution to such clogging problems.

Patent Application Publication No. 1986-71260 (Patent Application No. 1983-
178201), etc., an inkjet printer of the type shown in FIG. 6 has been proposed.

This type of inkjet printer is constructed of a combination of an ink container (film) 1 having a large number of ink storage holes 10 and a thermal head 2, as shown in FIG. 6(5).

The principle of ink ejection is explained by moving the ink container 1 in the direction of the arrow in FIG.

Ink from the ink supply section 3 is filled into each ink storage hole 10 of the ink container 1, and the ink storage hole 10 filled with ink passes over each heat generating element 20 of the thermal head 2 while being in contact with the ink storage hole 10.

When the heating element 20 is driven and the ink in the ink storage hole 10 is heated, a part of the ink is vaporized and bubbles are generated as shown in FIG. Finally, as shown in FIG. 6 (q), the ink in the ink storage hole 10 is ejected by the bubble.

In such an inkjet printer, there is no so-called ink nozzle, and the ink is ejected by heating the ink in the ink storage hole 10 of the thermal head 2, so in principle, clogging does not occur.

[Problem that the invention seeks to solve]

On the other hand, even in inkjet printers, gradation expression is required for recording shading, and this requirement is particularly strong when recording images other than characters.

However, in the conventional inkjet printer described above, the heating element 20 in the ink container 1
The number of ink storage holes 10 that are in contact with the ink storage hole 10 at one time is constant,
Since the size of the ink storage hole 10 is also constant, the amount of ink ejected by each heating element 20 is constant9.
There was a problem that gradation could not be expressed.

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide an inkjet printer that can perform gradation recording without clogging.

[Means for solving problems]

FIG. 1 is a diagram explaining the principle of the present invention.

In the figure, the same parts as those shown in FIG. 6 are indicated by the same symbols.

In the present invention, there are a plurality of ink containers (a in the figure) in the ink container 1.

The two areas (b) are set.

In regions a and b, as shown in FIG. 1(5), the ink storage holes 10 have the same size, but their arrangement densities are different, with region a having a higher density than region A.

In FIG. 1 CB), the arrangement density of the ink accommodation holes 10 is the same, but the sizes of the ink accommodation holes 10 are different, and the size of the ink accommodation holes 10 in area a is different from that in area a. The size of the ink storage hole 11 is υ larger.

That is, the ink accommodation amount per unit area υ in the ink container 1 is different between regions a and b.

Therefore, if area a is selected, high-density recording is possible, and if area s is selected, low-density recording is possible.

[For production]

In the present invention, since the ink container 1 is provided with a plurality of regions a and b that have different ink storage capacities per unit area, the ink storage capacity for each heat generating element 20 of the thermal head 2 also changes. .

For example, in the case of FIG. 1 (5), each heating element 2
The number of ink storage holes 10 relative to 0 is region a.

Since the numbers b are different, the number of ink droplets ejected by driving each heat generating element 20 is also different, making it possible to perform pre-recording with a different number of ink droplets per dot.

On the other hand, in the case of FIG. 1(B), each heating element 20
Since the size of the ink storage hole is different between regions a and b, the size of the ink droplet ejected by driving each heat generating element 20 is different.

It becomes possible to perform gradation recording by changing the size of ink particles per dot.

〔Example〕

(a) Description of the first embodiment FIG. 2 is a block diagram of the first embodiment of the present invention.

In the figure, the same parts as those shown in FIGS. 1 and 6 are indicated by the same symbols, and 40 and 41 are feed rollers, which connect the endless ink container 1 to the thermal head 2 and supply ink. This is for circulating between parts 3.

In this embodiment, an ink containing body (hereinafter referred to as a film) 1 is provided with a large number of ink containing holes 10 having a diameter of several tens of micrometers, and regions a, b, and C in which the ink containing holes 10 are arranged in different densities are provided. It is provided. area a,
As shown in FIG. 2, b and c, the arrangement density of ink storage holes 10 having the same diameter is different from high, medium, and low.

Then, the film 1 comes into close contact with the plurality of heat generating elements 20 of the thermal head 2 and moves around between it and the ink supply section 3.

Even in the low-density region C of the film 1, by arranging each heat generating element 20 to correspond to at least one ink storage hole 10, each heat generating element 20 of the thermal head 2 can be arranged so that the region C comes to the front. At least one ink droplet can be ejected even if the

A larger number of ink droplets can be ejected in the region A, and an even larger number of ink droplets can be ejected in the region a.

Therefore, if each heating element 20 corresponds to one pixel, high-density recording can be performed by driving one heating element 20 when area a of the film 1 comes to the front of the heating element 20, and area C of the film 1 By driving the heat generating element 20 when the light reaches the front surface of the heat generating element 20, low-density recording can be performed.

Since the film 1 is circulated by the feed rollers 40 and 41, each area arrives in the order of areas a, b, and c in front of the heat generating element 20 of the thermal head 2, so that each area is moved according to the specified density. hand.

By selectively driving the heating element 20 in accordance with the feeding of the film 1, it is possible to record at a desired density.

If the heating element 20 of the thermal head 2 is provided for one line, and the width of the film 1 is also set for one line, it can be used as a line printer, and the ink supply section 3.
By mounting the film 1 and the thermal head 2 on a carriage and moving the carriage in the main scanning direction of the recording paper, it can be used as a serial printer.

(b) Description of the second embodiment FIG. 3 is a block diagram of a second embodiment of the present invention.

In the diagram, + 1a + lb, 1c, and lcl are each F/L.
/mu, and the area al b is similar to film 1 in FIG.
.

The one with C! 2al 2bl 2e, 2d
2 are thermal heads, each of which is the same as the thermal head shown in FIG.

30, 31, 32, and 33 are ink tanks, each storing ink of a different color.

42.43 and 44.45 are sponge rollers.

Each of the endless films 1a to 1a is brought into close contact with the thermal heads 2a to 2d and sent around, and the ink from the corresponding ink tanks 30 to 33 is sucked up and filled into the ink storage holes 10 of the films 1a to 1d. .

In this embodiment, each film 1a to 1d is filled with ink of a different color 2, for example, yellow.

They are magenta, cyan, and black. Therefore, by driving each thermal head 2a to 2d, each film 1a to 1
4 colors of ink are ejected from side to side.

By mounting these on a carriage and moving them in the main scanning direction of the paper 5, a color inkjet printer can be configured.

In this case as well, each of the films 1a to 1d is provided with regions a, b, and c having different densities of ink storage holes 10, so the same procedure as in the case of FIG. 2 is performed.

Gradation recording with varying density can be achieved for each color.

(C) Description of the third embodiment FIG. 4 is a block diagram of a third embodiment of the present invention.

In the figure, the same parts as shown in FIGS. 1, 2, and 3 are indicated by the same symbols, and 6 is a platen;
7 is a carriage that supports the recording paper 5 and is provided opposite the thermal head 2;
F3a and gb are film shift mechanisms that move in the main scanning direction SP of the paper 5 along guides 70 and 71 by a carriage moving mechanism (not shown). While supporting both ends of the film 1 provided along.

The film 1 is shifted in the vertical direction 8F.

In this embodiment, as shown in FIG. 4(B), the film 1
Areas a, b, and c are provided in the width direction of the area, and each area a,
In b and c, the arrangement density of ink storage holes is the same,
Ink receiving holes 10, 11, 12 of different sizes are provided.

Therefore, by the shift mechanism $a, 13b, the film 1
By associating area a with the heating element 20 of the thermal head 2, ink is ejected from the ink storage hole 10 in area a, allowing high density recording.

If area C is associated with the heat generating element 20 of the thermal head 2, ink is ejected from the ink storage hole 11 of the area C, allowing medium density recording.If area C is associated with the heat generating element 20 of the thermal head 2, the area Ink is ejected from the ink storage hole 12 of C, allowing low density recording.

Further, the film 1 is provided along the moving direction SP of the carriage 7 and is fixed in this direction.

As the carriage 7 moves, each of the ink storage holes 10 to 12 of the film 1 is filled with ink from the ink supply section 3 on the carriage 7. Therefore, there is no need to move the film 1 around in order to fill the ink storage holes 10 to 12 of the film 1 with ink, and the film 1 is automatically filled with ink by the movement of the carriage 7.

In this way, the thermal head 2 moves in the main scanning direction by the movement of the carriage 7, and the shift mechanisms 8a, 8b
Area a of film 1 selected in .

Serial inkjet recording becomes possible by ejecting ink from b and c.

(d) Description of the fourth embodiment FIG. 5 is a block diagram of a fourth embodiment of the present invention.

In the figure, the same parts as those shown in Fig. 4 are indicated by the same symbols, and ga and gb are the film winding 9 iso structure.
The film 1 provided along the moving direction SL of the carriage 7 is wound up and moved along the moving direction SL.

In this embodiment, as shown in FIG. 5(B), the film 1
Regions a, b, and c are provided in the longitudinal direction of the paper width, and each region a, b, and c has the same density of ink storage holes, but different sizes of ink storage holes 10. 11.
12 are provided.

Therefore, by the operation of the two winding mechanisms 9a, 9b.

If area a of the film 1 is selected and positioned in front of the paper 5, the carriage 7 is moved using the ink storage hole 10 of area a.
By moving the thermal head 2, serial printing is performed by ejecting ink from the thermal head 2, and high-density recording is possible.Similarly, if area C is selected, medium-density recording is possible, and if area C is selected,
Low density recording is possible.

In this case as well, as in the embodiment shown in FIG. 4, the ink storage holes 10 to 12 of the film 1 are filled with ink from the ink supply section 3 on the carriage 7 as the carriage 7 moves.

(e) Description of other embodiments In the embodiments described above, the shape of the ink storage hole is shown as a prototype, but other shapes can be used as necessary. Although it is an open hole, it may be a recessed portion.

Further, the configuration of the embodiment shown in FIG. 2 (5) may be changed to a vertical type, and a monochrome serial printer may be used, as shown in FIG.

The film 1 shown in FIG. 2 may be applied to the serial printer shown in FIG. 5, or conversely, the film 1 shown in FIGS. 4 and 5 may be applied to the configuration shown in FIG. 2.

Although the present invention has been described above with reference to examples, the present invention can be modified in various ways according to the gist of the present invention.

These are not excluded from the present invention.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to perform gradation recording in an inkjet printer using an ink container and a thermal head, which can solve the problem of ink clogging, and to use other ink nozzles. Multi-tone recording, which is considered difficult even with conventional inkjet printers, can be achieved by inkjet recording.

Further, the necessary means for this purpose is simple and easy, which has an excellent practical effect, and can be realized simply and easily.

[Brief explanation of drawings]

FIG. 1 is a diagram explaining the principle of the present invention. FIG. 2 is a configuration diagram of a first embodiment of the present invention. FIG. 3 is a configuration diagram of a second embodiment of the present invention. FIG. 4 is a configuration diagram of a third embodiment of the present invention. FIG. 5 is a configuration diagram of a fourth embodiment of the present invention. FIG. 6 is an explanatory diagram of the prior art. In the figure, 1... ink container. 2.2a, 2b, 2c, 2d...-f--qh)"
. 3... Ink supply section. 10.11.12 ... Ink accommodation hole. a, b, c... area.

Claims (1)

[Scope of Claims] Ink is supplied to the ink storage holes of an ink storage body (1) having a large number of ink storage holes (10, 11), the ink storage body is brought into contact with the thermal head, and the ink storage body (10, 11) is brought into contact with the thermal head. In an inkjet printer that ejects ink from the corresponding ink storage hole of the ink container onto a recording medium by driving, the ink container has a plurality of regions (a) each having a different density or hole size of the ink storage hole. ,b,
c), and performs gradation recording by selecting a desired area of the ink container and changing the amount of ink ejected from the ink container by driving the thermal head.