JPS5882767A - Picture recorder - Google Patents

Abstract

PURPOSE:To raise the quality of print by a method in which the first and second paired electrodes are independently provided from the opening portion to the inside of nozzles whose tips are put close to or contacted with a recording paper, and the level of a dielectric ink is controlled by voltage application to these paired electrodes. CONSTITUTION:A dielectric ink 1 is supplied from an ink trap 3 into nozzles 2 proided in rows, and the first paired electrodes 5a and 5b are provided near the opening of the inner wall of the nozzles 2 and the second paired electrodes 10a and 10b are independently provided from the opening portion to the inside of the nozzles 2. These paired electrodes are each connected to power sources 6a and 6b and the application of voltage to these paired electrodes is controlled by switches 7a and 7b. During non-recording period, voltage is applied only to the second paired electrode, the level of the ink is controlled to near the boundary between both the paired electrodes. Also, during recording period, voltage is applied to both the paired electrodes, the ink level is projected from the nozzles, and recording is made on a recording paper 8 on the platen 9.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image recording device using dielectric ink.

The above-described image recording apparatus has been proposed as an image recording apparatus that requires a low recording voltage and has a simple configuration, in contrast to the electrostatic inkjet recording method that requires a high recording voltage.

A brief explanation will be given below using FIG. 1. FIG. 1 is a schematic diagram of the structure of the image recording apparatus. In Figure 1, (l
) is dielectric ink (hereinafter referred to as ink), (2) is insulator nozzle (ink supply hole), (2aX2b) is nozzle wall, (3) is ink reservoir, (4) is ink reservoir (3) The ink liquid level (5a) (5b) is the nozzle wall (2g) (2
b) A parallel plate electrode pair (hereinafter referred to as an electrode pair) provided inside the electrode pair (hereinafter referred to as an electrode pair), (6) a power source that applies a voltage between the electrode pair (5a) and (5b), and (7) an electrode pair ( sa) (5b)
The switch (8) controls the voltage application between the nozzle (
2) is a recording paper brought close to the leading edge; (9) is a running guide for the recording paper. The tip of the electrode (sa) (5b) is placed at almost the same position as the tip of the nozzle (2),
2) is connected to the ink reservoir (3).

FIG. 2 shows the shape of the leading end of the recording section. As shown in the figure, it has a structure in which multiple nozzles (2) are arranged, and each nozzle (
2) A pair of electrodes (6m) (6b) are arranged inside.

The operation during recording is as follows.When not recording,
The liquid level of the ink (1) in the nozzle (2) is determined by the electrode pair (5).
a) Hold at a predetermined position (position (b)) below from the tip between (5b). This position is at a height of Hl from the liquid level (4) of the ink reservoir (3), which is controlled to maintain a constant liquid level, and is determined by the capillary suction force of the nozzle (z). At this time, no voltage is applied between the electrode pair (6a) (5b).

During recording, the switch (7) is turned on as indicated by the broken line in the figure, and a voltage is applied between the electrode pair (5m) and (6b).

Then, it is better to fill the entire space between the electrode pairs (5m) (5b) with the ink (1), which is a dielectric material, for the electrode pairs (5i) (5b).
) is large, so ink (1) receives a Coulomb force in the direction of increasing electrostatic energy, and in the figure, a force moves upward on ink (1).

By applying a sufficient voltage, the ink (1) overcomes resistance such as its own weight and moves upward, filling the entire space between the electrode pair (5a) (5b).

Further, at the tip of the electrode pair (5a) (5b), the electrode (5a)
Due to the edge effect of the ridge at the tip of (6b), an electric field is formed not only upward from the tip, but also from the electrode pair (5i+) (
The ink (1) is pulled up to the tip of the nozzle (2) (position (2) indicated by Hl in FIG. 1), which is slightly raised from the tip of the nozzle (2). Ink at this time (1)
Since the recording paper is arranged so that the ink (1) adheres to the ridge of the recording paper (0), the ink (1) adheres to the recording paper (0) to form pixels and recording is performed.

Image recording over the entire recording width is performed by selectively applying a voltage to a pair of electrodes in a nozzle corresponding to a recording position in accordance with an image signal. Furthermore, instead of arranging a plurality of nozzles, a structure in which a plurality of electrode pairs are arranged at predetermined intervals within a slit has also been proposed as an even simpler structure.

This recording method is the same as the nozzle method described above.

However, the nozzle type and slit type image recording apparatuses using dielectric ink described above have the following drawbacks.

In the nozzle type, the liquid level position of the ink (1) during non-recording is determined by the capillary suction force of the nozzle, so when the voltage application between the electrode pair is released and the state changes from the recording state to the non-recording state. The moving speed of the ink (1) liquid level (the speed of moving from H2 to Hl in FIG. 1) is slow (and noise such as trailing is likely to occur on the image).

In addition, the slit type has the same drawbacks as the nozzle type mentioned above, and there is no partition between adjacent electrode pairs like the nozzle type, and the ink (1) is connected, so the ink (1) is connected to the electrode pair next to the electrode pair to be recorded. The liquid level of the ink (1) on the non-recording electrode pair is raised, and the ink swell at the tip of the recording electrode pair becomes thicker than necessary, which increases the size of the pixels and tends to reduce the resolution of the image.

Furthermore, the ink liquid level between the two pairs of recording electrodes and the non-recording electrode pair is likely to be pulled upward from a predetermined position due to the surface tension of the ink (1), resulting in noise on the image.

The present invention solves the above-mentioned drawbacks, and each electrode pair is configured with two stages of electrode pairs in the ink supply direction, and voltages are applied independently to these pairs, thereby improving the response of the ink. The object of the present invention is to provide an image recording apparatus that has good performance and is capable of forming high-quality images with less noise as described above.

Embodiments of the present invention will be described below based on the drawings.

FIG. 3 is a schematic configuration diagram of an image recording device that is an embodiment of the present invention, FIG. 4 is an enlarged perspective view of the tip of the recording section of the same device, and FIG.
The figure is an explanatory diagram of the recording voltage application method, and FIG. 6 is an explanatory diagram of the operation inside the leading end of the recording section. The image recording device of this embodiment basically has a configuration in which a plurality of electrode pairs are arranged within a slit, and most of the schematic configuration is the same as the image recording device described in FIG. Detailed explanations of these will be omitted.

In Figure 8, (1) is dielectric ink, (2) is insulator slit (ink supply hole), (2a) (2b)
is the slit wall, (3) is the ink reservoir, (4) is always controlled at a predetermined position and the liquid level of the ink reservoir (3), (5a) (5
b) is a pair of parallel plate electrodes arranged approximately parallel to each other on the inside of the slit wall (2a+) (jb), the tips of which are located approximately at the same position as the tip of the slit (2); ), the parallel plate electrode pair (6m) and (6b) are the electrode pairs (5aX5b) and (10m) ( 10b) A power supply for applying a voltage between each of the electrodes (7a) (Wb) is an electrode pair (5aX5b)
and (10a) (Sob), (8) is a recording paper brought close to the tip of the slit (2), and (9) is a running guide for the recording paper. be. Electrode pair (5a) (5b) and electrode pair (10aX10b
) means that an insulator such as slit II (2a) (
! ! b) and are electrically independent from each other.

Next, the electrode pair will be explained with reference to FIGS. 4 and 6.

Specifically, the electrode pair has a configuration as shown in Figure 4, and is connected to a power source (6
), and the relationship with the switch (7) is schematically shown in FIG. 6. In other words, the minimum required 1 for the entire recording width is
If the number of pixels per line is n, the electrode (5a) is n
The electrodes (5b) * (
10a) and (10b) are at least n of electrode (5a)
It consists of one sheet placed opposite each other. Therefore, the number of switches (7a) is (7aX) to (7an) corresponding to the n electrodes (6at) (Ban).

Next, the operation will be explained using FIGS. 8 to 6.

To simplify the explanation, one row of electrode pairs will be explained first. FIG. 8 shows a cross section of the slit (2) at an arbitrary pair of electrodes.

The liquid level of ink (1) when no recording operation is performed is:
By controlling the liquid level (4) of the ink reservoir (3), the electrode pair (10 m
) (1ob). This position is the height at which the ink (1) rises due to the capillary suction force of the slit (2). When performing a recording operation, the liquid level of ink (1) is maintained at Hl during non-recording and at aS during recording. During the recording operation (regardless of recording or non-recording), a voltage equivalent to the recording voltage is applied between the electrode pairs (lea) (10b), and only during recording.
) by applying a recording voltage between them.

That is, during the recording operation, ink (1) is applied to the electrode pair (10 m
) (10b), and the electrode pair (10m) (10b) is held electrostatically between
) due to the edge effect of the ridge at the tip of the electrode pair (11m) (10b
), an electric field is formed slightly above the tip.
The liquid level of the ink (1) is maintained at a position slightly raised from the tips of the electrode pair (10s+) (10b). This position is H. On the other hand, during recording, an electrode pair (5m) (5b
), an electric field is formed by the recording voltage, so the ink (1) rises and is held between the electrode pair (5a) (5b). Then, the liquid level of ink (1) is the electrode pair (5aX5b
) is held in a slightly raised position from the tip. This amount is Hz. At this time, the tip of the ink (1) - the recording paper (
6) to form pixels. The reason for this is as described above.

After the recording is completed, the voltage application between the electrode pair (5a) (sb) is stopped by the switch (7a), so that the ink level position returns to the Hl position.

Recording over the entire recording width is performed as follows. 6th
In the figure, during the recording operation, switches (7ax) to (〒in) are turned on in accordance with the image signal.

FIG. 6 shows the inside of the slit (2) during recording, and is a view of a central cross section of the tip of the slit (2) during recording, viewed from the direction of the arrow in FIG. In Figure 6, ink (1) is placed at ■2 at the position of the recording position electrodes (5as) (5a,)
It is shown that the ink (1) has descended to the Hl position at other non-printing positions.

Here, the voltage applied between the electrode pair (5m) (5b) is V.

When the voltage applied between the electrode pair (xoa) (tab) is V, the relationship is V≧V. This means that when v<v, the electrode pair (1
This is because the electric field between the electrode pairs (10b) becomes stronger than the electric field between the electrode pairs (5iX5b), and the liquid level of the ink (1) does not rise from H during recording. The optimal value of V is v=V. Under this condition, the holding force of the ink (1) between the electrode pair (10a) (10b) is the strongest.

As explained above, since the liquid level of the ink (1) is held electrostatically during non-recording, the liquid level of the ink (1) is not determined simply by the capillary suction force of the slit, unlike conventional devices. Stronger surface holding power. Therefore, when changing from the recording state to the non-recording state, the moving speed of the ink (1) liquid level (the speed of moving from Hl to Hl in FIG. 8) is faster than in the conventional apparatus,
The occurrence of noise such as trailing on images is reduced.

In addition, the liquid level of the ink (1) between the pair of electrodes that are not to be recorded next to the pair of electrodes that are to be recorded is raised, and the rise of the ink (1) at the tip of the pair of electrodes that are to be recorded becomes larger than necessary. This also eliminates the disadvantage that the image resolution decreases due to the increase in size.

Furthermore, it is possible to solve the problem that the ink liquid level between the two pairs of recording electrodes and the non-recording electrode pair is pulled up by the surface tension of the ink (1) and adheres to the recording paper, causing noise on the image. .

Although a slit-type image recording apparatus is shown as an example, the above-mentioned effects of reducing problems such as trailing noise can be similarly obtained even when applied to a nozzle-type image recording apparatus.

In addition, although the example shows the case where the slit faces upward, there is no problem even if the slit is tilted, and since the ink liquid level is held by an electric field, the holding force is strong (the slit is placed almost horizontally). No problem.

As explained above, according to the present invention, the first and second electrode pairs, which are electrically independent of each other, are provided in order from the dielectric ink supply hole opening of the head member to the back side, and when not recording, the second electrode pair is provided.
By applying a voltage to the electrode pair, the liquid level of the dielectric ink was maintained near the boundary between the first and second electrode pairs.
An image recording device capable of recording high-quality images with an overall better S/N than conventional devices has been obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an image recording device, FIG. 2 is an enlarged perspective view of the tip of the recording section of the same device, and FIG. 8 is an image showing an embodiment of the present invention improved from FIGS. 1 and 2. A schematic configuration diagram of the recording device, FIG. 4 is an enlarged perspective view of the tip of the recording section of the device, and FIG.
The figure is an explanatory diagram of the recording voltage application method, and FIG. 6 is an explanatory diagram of the operation inside the leading end of the recording section during recording. (1)...Dielectric ink, (2)...Slit or nozzle, (5m) (5b)-first electrode pair, (6a)
(6b)...Power supply, (7b)...Switch, (8)...Recording paper, (tea) (lob)...
Second electrode pair agent Yoshihiro Morimoto Figure 1, Figure 2, Figure 5, Figure 4, Figure 5

Claims (1)

[Scope of Claims] 1. Inside the supply hole on the back side from the dielectric ink supply hole opening of the insulating head member, with the tip thereof positioned at the supply hole opening of the head member and opposed to each other at a predetermined distance. An electrode pair consisting of two electrodes is provided, and the liquid level position of the dielectric ink filled in the supply hole of the head member is controlled by the presence or absence or degree of voltage application to the electrode pair, and recording is performed. In an image recording apparatus in which dielectric ink is sometimes deposited on a recording paper that is in close proximity to or in contact with the head member, the electrode pairs are arranged in order from the supply hole opening side of the head member into first and second electrodes that are electrically independent of each other. The liquid level position of the dielectric ink is determined near the boundary between the first and second electrode pairs by applying a voltage to the second electrode pair when not recording.
An image recording apparatus characterized in that during recording, a voltage is applied to both the first and second electrode pairs so that they are held near the supply hole opening of the head member. 1 The voltage applied to the first and second electrode pairs is
2. The image recording apparatus according to claim 1, wherein the relationship is V≧V, where V and V.