JPH02235643A - Ink jet type recorder - Google Patents

Abstract

PURPOSE:To prevent decrease of recording density by a method wherein a control means by which transfer speed of a film is made quicker than a recording speed in a main scanning direction is established. CONSTITUTION:A control circuit 18 is connected to a motor 12 and a thermal head 15 respectively via a film feed driver 16 and a head driver 17, and transfer speed of a film 10 is so controlled as to be made quicker than recording speed (the recording speed in a main scanning direction) of the thermal head 15 by the control circuit 18. Then, a slight gap (this gap is formed by slack of the film 10 due to high speed transfer of the film 10) is formed between the film 10 and the thermal head 15, and ink 14 staying in this gap is jetted. Therefore, recording density becomes thicker and besides, stable recording can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention 1 <<Industrial Application Field>> The present invention relates to an inkjet recording device, and more particularly, the present invention relates to an inkjet recording device, and in particular to a recording medium that uses heat power to fill ink filled into small holes formed in a film. The present invention relates to an inkjet recording device that performs recording by ejecting water.

(Prior Art) When recording methods for recording stamps are classified into class IIi, etc., they are classified into impact methods and non-impact methods. Non-impact recording devices essentially have advantages over impact recording devices, such as lower noise and smaller size.

By the way, an inkjet recording device, which is one of the non-impact recording methods fIII, is one in which dots are formed on a recording medium by ejecting ink particles from a nozzle and colliding with the recording medium.
Although it has the advantage of being easy to perform color recording, it has the problem that the nozzles are easily clogged and it lacks stability as a recording device.

Therefore, in recent years, inkjet recording devices have been proposed that can significantly reduce nozzle clogging.

FIG. 5 is a schematic diagram showing the basic structure of the inkjet recording@cocoon of A. As shown in this figure, film 1 is
It is freely arranged to run (from left to right in the figure) close to the recording surface 2a of the recording medium 2 such as paper. The film 1 is provided with a large number of small holes 1a having a diameter of several tens of micrometers at a pitch of several tens of micrometers, and the small holes 1a are provided on the surface opposite to the recording surface 2a.
An ink supply rod 4 is abutted as an ink supply means for filling ink 3 into the ink. Further, a thermal head 5 is brought into contact with the surface opposite to the recording surface 2a on the front side of the ink supply rod 4, with the base thickness being from the left to the right in the moving direction of the film 1.

On the contact surface of the thermal head 5 with the film 1, a large number of heating elements 5a are provided at a predetermined pitch in the width direction of the film 1. The movement is controlled in the same direction.

Although not shown in the figure, the recording medium 2 and the recording medium 2 are connected to respective moving mechanisms.

The conventional inkjet recording apparatus to which the present invention is applied is configured as described above, and the ink supply rod 4 fills each small hole 1a of the film 1 with ink 3, and the ink 3 is heated by the thermal head 5. Give power and make bubbles,
Recording is performed by ejecting bubbled ink particles 6 onto the recording surface 2a (hereinafter, such a recording method will be referred to as a thermal inkjet recording method).

That is, since a plurality of heating elements 5a are attached to the contact surface of the thermal head 5 with the film 1 in the width direction of the film 1, the desired heating element 5a on the back of these heating elements 5a is energized. Only the ink 3 that has filled the small hole 1a passing over the heated heating element 5a turns into ink particles 6 and is ejected onto the recording surface 2a, making it possible to use only the ink 3 corresponding to the dot image for recording. can.

Further, the thermal head 5 performs the same operation as a thermal head in a known thermal transfer recording device, and the film 1 corresponds to the ink ribbon in the same device.

Here, the state of the ink 3 in the small hole 1a by the thermal inkjet recording 1 type described above is shown in FIGS. 6(a) to 6(a).
+) will be explained. Ink 3k filled in small holes 1a of film 1, heating element 5a of thermal head 5
By applying heat power, bubbles 7 are formed in the ink 3 (see FIGS. 6(a) to 6(c)). and,
The air bubbles 7 push out the upper part of the ink liquid, forming a so-called steam dome 8, and this steam dome 8 collapses to eject ink particles 6 (Fig. 6(d) to (e)). Ink particles 6 After being ejected, the heating element 5a is exposed for a while and comes into contact with the air, and then the ink 3 oozes out from around the small hole 1a, and the heating element 5a is covered with the ink 3 again. It returns to its original state (Fig. 6 ([) to (i
)).

(Problem to be Solved by the Invention) By the way, in the thermal inkjet recording method described above, after the ink particles 6 are ejected, the heating element 5a is exposed until the ink 3 enters from the surroundings (see FIG. 6(f)).
)reference". If an attempt is made to record without the ink 3, not only will the ink particles 6 not be ejected and "dry firing" will occur, but the temperature of the heating element 5a will rise higher than necessary and the heating element 5a will deteriorate. There was a problem of shortened lifespan.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide an inkjet recording device that can perform high-quality recording by preventing "dry firing" in which ink particles do not reach the recording medium during recording. It is something to do.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the present invention provides a film having a large number of small holes and provided to run close to the Bts body. an ink supply means for supplying ink to the small holes of the film, and applying heat power to the small holes of the film to which the ink is supplied by the ink supply means to transfer the ink in the small holes to the recording medium. The inkjet recording apparatus has a thermal head that ejects jets toward the inkjet recording apparatus, characterized by comprising a control means for controlling the moving speed of the film to be faster than the recording speed in the main scanning direction.

Further, a film having a large number of small holes and provided close to a recording medium, an ink supply means for supplying ink to the small holes of the film, and an ink supply means when the film is stationary. 1r where ink is supplied by
In an inkjet recording apparatus having a thermal head that applies heat power to small holes in an i-distributed film to eject ink in the small holes toward the recording medium, the head driving frequency of the thermal head during recording is 20°C.
It is characterized by having v1611 means for controlling the frequency to be 0 Hz or less.

(Function) According to the present invention, ink can always be filled into the small pores of the film during recording, and high-quality recording without "dry firing" can be performed.

(Example) Hereinafter, the present invention will be explained in detail based on the illustrated example.

FIG. 1 is a configuration diagram showing an inkjet recording device according to claim (1) of the present invention. As shown in this figure,
An endless film 10 made of polyimide or the like having a predetermined width is rolled between two rollers 11a. 1lb, and is moved by the drive of a motor 12 connected to a roller 11a. In film 10,
A large number of small holes 10a formed with a pitch of several tens of microns and a diameter of several tens of microns are arranged in a staggered manner, for example, in an equilateral triangle shape.

Further, the lower part of the film 10 is connected to an ink supply vat 13.
The film 1 is penetrated by the ink 14 injected into the film 1.
The heating element 15a of the thermal head 15 is tightly attached to the inside of the thermal head 15. The heating element 15a is the thermal head 1
5 are provided at a predetermined pitch in the width direction.

A control circuit 18 is connected to the motor 12 and the thermal head 15 via a film feed driver 16 and a head driver 17, respectively. The recording speed in the main scanning direction is controlled to be faster (the R details will be described later).

In addition, in front of the film 10, a recording medium 20 such as paper that is movably supported by a platen roller 19 is disposed adjacent to the recording surface 20a of the recording medium 10 and the inside of the film 10. The thermal head 15 provided on the front side faces the thermal head 15 . The recording medium 20 moves in the same direction as the film 10 (in the direction of the arrow) by a movement mis (not shown).

Next, the operation of the above-described inkjet type recording apparatus according to the present invention will be explained. To perform recording on the recording medium 20, first, the small holes 10a are filled with the ink 14 at the bottom of the film 10 that has permeated with the ink 14, and the motor 12 is driven to rotate the rollers 11a and 11b.
is moved in the direction of the arrow, and the recording medium 20 is moved in the same direction as the film 10 (in the direction of the arrow) by a moving mechanism (not shown).

Then, when the small hole 10a filled with the ink 14 comes to the position of the thermal head 15 due to the movement of the film 10,...
A voltage is applied to the thermal head 15 to generate the desired heating element 1.
The ink 14 in the small hole 10a is heated by applying heat power to the ink 5a.
The ink particles are turned into bubbles and the pulverized ink particles are transferred to the recording surface 20a.
to record according to the dot pattern (6th
See Figures (a) to (i>).

At this time, if the recording speed of the thermal head 15, that is, the frequency of the voltage application signal (drive signal) to the heating element 15a (head drive frequency) is f, and the dot pitch to be recorded intersects, then the main scanning speed of the thermal head 15 is Directional record speed r! lv
becomes v-f-official...《1》. Therefore, in the present invention, in order to run the film 10 at a speed higher than the main scanning recording speed determined by the formula
outputs the l a signal to control the drive of the motor 12,
The movement of the film 10 is controlled. FIG. 3 is a graph showing the relationship between the moving speed of the film 10 and the recording density. Each recording speed in the graph is the main scanning direction recording speed when recording using the serial recording method, and is 8 dots.
/ When recording at srs resolution. The head drive frequency corresponding to each recording speed is 8.
In case of 0 as/sec, 600Hz, 40mm
/sec, 300Hz, 2011/SeG
In this case, it is 150Hz.

As is clear from this graph, the head drive frequency is 1
In the case of 50Hz, the recording density does not decrease even if the film movement speed is below the above speed, whereas when the head drive frequency is 300Hz. It can be seen that in the case of 600 HZ, when the film moving speed becomes slower than the recording speed, the recording density decreases to the lti end. Also, the head drive frequency is 200H.
It can be seen that when it is higher than z (driving frequency limit value when the film is stationary), it is necessary to move the film 10 at a speed equal to or higher than the recording speed. Further, when the film 10 is moved at a speed higher than the recording speed, the film 10 and the thermal head 15 are
A slight gap (this gap is formed when the film 10 lifts up due to the high speed movement of the film 10) is formed in the darkness, and the ink 14 accumulated in this gap is ejected, causing the recording density to fall. This allows for stable recording. This action and effect can only be obtained when the film 10 is moved at a recording speed or higher, and its advantages are great. Also, the head drive frequency is 200
When the driving frequency is lower than Hz (driving frequency limit value when the film is stationary), the film 10 may be moved slower than the recording speed.

The film 10 used in the measurement was an equilateral triangular pattern with a thickness of 15 μm, a diameter of the small holes 10a of 30 μm, and a distance between the centers of each small hole 10a of 45 μm. Further, the head pressing force of the thermal head 15 against the film 10 is 1 g/IllIl. As a result of experimenting with the film 10 having the small holes 10a arranged in this manner using a heating element 15 of 1OOμIXIOOμ, it was possible to perform the best recording.

FIG. 2 is a configuration diagram showing an inkjet recording apparatus according to claim (2) of the present invention. As shown in this figure,
A film 30 made of polyimide or the like is fixed by a head cartridge 31.

In the noilum 30, a large number of small holes 30a, which are formed at a pitch of several tens of microns and have a diameter of several tens of microns, are arranged in a staggered manner, for example, in a triangular shape. Further, the heating element 15a of the thermal head 15 fixed to the head cartridge 31 is closely attached to the inside of the film 30, and the ink 14 is filled around the heating element 15a. The heating element 15a is the thermal head 15
A large number of them are provided at a predetermined pitch in the width direction. A control circuit 18 is connected to the thermal head 15 via a head driver 17, and this control circuit 18 allows
The head drive frequency of the thermal head 15 is 200
Hz or less (details will be explained later)
.

Further, in front of the film 30, a recording medium 20 such as paper, which is movably supported by four platen rollers 19, is disposed close to the recording medium 20, and a recording medium 20 is disposed on the recording surface 20a of the recording medium 20 and on the inside of the film 30. The thermal head 15 is opposite to the thermal head 15 . The recording medium 20 is moved by a moving mechanism (not shown).

Next, the operation of the inkjet recording device according to the present invention described above will be explained. To record on the recording medium 20, first, the small holes 30a of the film 30 are filled with ink 14, and the recording medium 20 is moved by a moving machine groove (not shown).
At this time, the film 30 is stationary. Then, a voltage is applied to the legal head 15 to apply heat power to a desired heating element 15a to bubble the ink 14 in the small holes 30a, and eject the bubbled ink particles onto the recording surface 20a to form a dot pattern. (Figure 6 (a)
) to (f)).

FIG. 4 is a graph showing the relationship between the ink filling time into the small holes 30a of the film 30 and the head pressing force of the thermal head 15 against the film 30 when the film 30 is stationary on the thermal head 15. It is. As is clear from this graph, the larger the head pressing force, the longer the ink filling time (the time from when the ink 14 is ejected from the small hole 30a until the heating element 15a of the thermal head 15 is covered with the ink 14 again) becomes longer. This is because the larger the head pressing force, the smaller the gap between the thermal head 15 and the film 30, making it difficult for the ink 14 to bleed. Furthermore, the higher the applied energy density, the longer the ink filling time.

This is because the higher the applied energy density, the more the ejected ink 14 hangs, and the more the exposed portion of the heating element 15a becomes. Furthermore, it can be seen that it takes at least about 51 seconds to fill the ink 14. Therefore, if the film 30 is stationary during recording, the thermal head 1
5, that is, the voltage application signal to the heating element 15a (
The limit value of the frequency (head drive frequency) of the drive signal is 2.
It becomes 00Hz.

The film 30 used in the measurement had a thickness of 15 .mu.m, a diameter of the small holes 30a of 30 .mu.m, and an equilateral triangular arrangement with a distance between the centers of the pores 30a of 45 .mu.m. In this way, small hole 3
08G: 100μ x 100μ of the 1f film
As a result of experiments using the first heating element 15a, it was possible to perform the best recording.

[Effects of the Invention] As described above in detail based on the embodiments, since the inkjet recording apparatus of the present invention is configured as described above, it produces the effects described below.

In the ink jet recording apparatus according to claim <<1>>, M is set such that the moving speed of the film is faster than the recording speed in the main scanning direction.
Because of this, during recording, the small holes filled with ink in the film always move near the heating element of the thermal head, preventing the recording arm from deteriorating and allowing high-quality recording to be performed at high speed.

Further, in the inkjet recording device according to claim (2),
By keeping the head drive frequency below 200Hz (the head drive frequency limit when the film is stationary), the small holes in the film are always filled with ink, which prevents "dry firing" in which ink does not eject, and improves quality. Furthermore, since "dry firing" in which ink does not eject during recording is prevented, the alt of the heating element of the thermal head is not increased more than necessary, and the life of the apparatus is extended.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the inkjet recording@cod according to claim <<1>> of the present invention, and FIG.
Fig. 3 is a graph showing the relationship between film moving speed and recording density, and Fig. 4 is a graph showing the relationship between the pressing force of the thermal head against the film and the ink filling time. The graph showing the relationship, Figure 5, is
FIG. 6, which is a schematic diagram showing the basic configuration of an inkjet recording apparatus, is an explanatory diagram showing a state in which ink is ejected to fill small holes in a film. 10.30...Film 10a. 30a...Small hole 12...Motor 14...Ink 15...Thermal head 15a...Heating element 16
・・・Film advance driver

Claims (2)

[Claims] (1) A film that has a large number of small holes and is provided to run close to a recording medium, an ink supply means that supplies ink to the small holes of the film, and an ink supply means that supplies ink to the small holes of the film. In an inkjet recording apparatus having a thermal head that applies heat power to small holes in the film being supplied and ejects ink in the small holes toward the recording medium, the moving speed of the film is set in the main scanning direction. An inkjet recording apparatus characterized by comprising a control means for controlling the recording speed to be faster than the recording speed. (2) a film having a large number of small holes and provided close to a recording medium; an ink supply means for supplying ink to the small holes of the film; and an ink supply means for supplying ink when the film is stationary. In an inkjet recording apparatus having a thermal head that applies heat power to small holes in the film to which ink is supplied by a means to eject ink in the small holes toward the recording medium, during recording, the thermal head The head drive frequency of the head is 200H.
1. An inkjet recording apparatus characterized by comprising a control means for performing control so that the inkjet recording apparatus is controlled to be equal to or less than z.