JPS58107359A - Ink jet printer - Google Patents

Abstract

PURPOSE:To accelerate an ink jet printer by connecting vibrating means for vibrating the ink injecting direction to the specific direction to an ON-demand type head having two ink chambers, thereby almost eliminating the time of folding at the moving end of vertical direction. CONSTITUTION:Two stays 33 are stood on a carriage 34 which opposes a drum 31 for engaging a recording sheet 32, thereby rotatably securing the right and left sides of an ink head 35. A bracket 35a is projected backwardly at the center on the back of the head 35, a projection 41 projected from the end side of a bimorph type rectangular piezoelectric vibrator 40 sidewisely is engaged with a long hole 35b opened at the bracket, thereby connecting the head 35 to the vibrator 40. A voltage is applied to the vibrator 40, thereby elevationally rotating the head 35. The rotation of the head 35 may be also performed by an electromagnet 42 and a permanent magnet 43.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inkjet printer, and an object thereof is to provide a flat scanning inkjet printer equipped with an on-demand ink head.

Among the on-demand type ink heads, a type called a stem type ink head having two ink-presenting chambers is known. 1st
The figure shows one example of this, in which the large-diameter opening of the cut-out part of the internal ink chamber 2 formed inside the head body is covered with a plate-shaped piezoelectric vibrator 3, and the small-diameter opening at the front of the internal ink chamber 2 is communicated. Hole 4a
A front plate 6 is installed parallel to the partition plate length to form an ink narrow (another ink chamber) 5 at a slight distance from this partition plate length, and this front plate 6 has an orifice 6ai formed concentrically with the communication hole 4a, and ink is supplied to this ink reservoir 5 via a tube 1 etc.
A square plate 8 is installed in parallel with a slight distance from the box, and an air outlet 8ai is opened in parallel with the oriice 6a, and compressed air is supplied from a tube 9 to the sealed space outside the air outlet 8a. I'll do it□It's sea urchin. When a pulse is applied to the piezoelectric vibrator 3, the piezoelectric vibrator 3Fi vibrates to apply pressure to the ink inside the internal ink chamber 2, ejecting ink droplets through the communication hole 4a and orifice 6af, and furthermore, this ink droplet is ejected by air. The air S ejected from the hole 8a assists the flight and directs it toward the recording paper (not shown). Since such an ink head (1) generates ink droplets only when printing is necessary; and (2) mechanically ejects ink droplets, the head system is simple.

■ The operating frequency is 10-20% higher than that of the single ink chamber type.
It is about 5 times higher than kHz.

It has the same length.

Contrary to fL, (2) The structure is a little more complicated than that of the one-chamber ink chamber type, and it is difficult to make it into a multi-nozzle type.

(2) As mentioned above, since multi-nozzle printing is difficult, the printing method is limited to the drum scanning method, such as the single head type.

There are disadvantages such as

In the drum scanning method, recording paper 12 is wound around a drum 110 as shown in FIG.
3. While rotating continuously at step 3, if the carriage is facing the drum 11, the scratches will be recorded from the ink head 15 with fixg.
The carriage 14 is connected to a wire F which is intermittently driven to rotate by a pulse motor 16, so that the carriage 14 and the ink head 15 can be moved in the longitudinal direction of the drum 11. The main scanning is performed by the rotation of the drum 11, and the sub-scanning is performed by the movement of the carriage 14.

On the other hand, in the plane scanning method, as shown in FIG.
is moved in the longitudinal direction of the drum 21 to perform printing.

In the latter method, the recording paper 22 is fed flatly, so the mechanism for feeding the recording paper is simple, and since the recording paper 22 can be used continuously, it is possible to print on long sheets of paper. It has the following advantages. On the other hand, if we pay attention to the ink head 25, it moves as shown in FIG. Sub-scanning is performed by moving the recording paper 22 one step, and the ink droplet 1 is added to the ink droplet 1 at the desired position.
*Shoot. When performing such scanning, since the dot generation rate by ejecting ink droplets is 10-gokHz, in order to print at a density of 4 pieces/bait, the if movement is set to 200 μs.

Now, if the width of the recording paper is 200B, then 200X20+)=4XlO'μa=40m8ec・
...(2i, and one main scan movement requires 40m5ec.

Assuming that 60 m5 ec is spent on turning back, 100 m5 ec is required per main scanning line, and as in the example shown in the figure [for printing one line in the case of a 5x7 dot matrix display], it takes OOmsec, f, and Kanji printing. Since 24 vertical dots is the standard, one line of printing rc2. Number s
ea, making it unsuitable as a printing device, and for this reason, it is impossible to put a planar scanning type inkjet printer into practical use with an on-demand type ink head with two ink chambers, such as a stator drum type. Ta.

As mentioned above, the present invention takes a long time to print one line because of the long turnaround time, and if this problem is solved, the advantage of the two-chamber ink head, which has a high operating frequency, can be utilized. This was done based on the viewpoint of That is, the plane scanning method in the inkjet printer of the present invention scans in such a way that the vertical direction is the main scanning direction and the horizontal direction is the sub-scanning direction, as shown in FIG. This vertical scanning is performed by vibrating the ink head and changing the direction of ink droplet ejection in the vertical direction. In this scanning method, only a small part (light weight) of the ink head is vibrated with a narrow amplitude, so almost no time is spent turning around at the end of the vertical movement, making it easy to increase the speed. FIG. 6 is a schematic diagram showing the structure of the main parts of the inkjet printer of the present invention. Drum 31 on which recording paper 32 is wound
Two stays 33 (only one stay 33 is shown in the figure) are erected on the carriage 34 which faces the ink head 350 and is movable in the longitudinal direction of the drum 31, separated by the width dimension of the ink head 350. At the upper end of the stay 33, approximately the center in the height direction of the left and right sides of the ink rack 35 is rotatably supported. A bracket 35ai protrudes rearward from the center of the back surface of the ink head 35, and a bimorph strip-shaped piezoelectric vibrator 40 protrudes laterally from the side surface of the tip end of a bimorph strip-shaped piezoelectric vibrator 40 in the elongated hole 35b. The ink head 35 and the piezoelectric vibrator 4 are loosely fitted into each other.
It communicates with 0. The tip of the piezoelectric vibrator 40ij is connected to the bracket 35a so as to be curved upward and downward when a voltage is applied to the piezoelectric vibrator 40ij, and the base end is fixed to the vertical portion of the carriage 34. An electrical signal of 200 to 400 Hz is applied to this piezoelectric vibrator 40 through a lead wire (not shown), and the piezoelectric vibrator 40 is moved up and down as shown by the two-dot chain line.
Curve repeatedly. As a result, the ink head 35 also rotates vertically and repeats vibrations. Now, suppose that 25 dots are recorded in the vertical direction, and the dot generation rate is 20 kHz as described above, 1 dot is 50 dots.
μsea f9, so +50X25X2=2.5m5
ec...(31) At 400H2, vibration of the ink head 35 corresponding to the dot generation speed of 20 kHz can be obtained. Note that X2ij on the left side of equation (3) represents the reciprocation of the head.

Note that it is effective to increase the amplitude and excitation force by utilizing the resonance point of the piezoelectric vibrator 40d.

FIG. 1 shows an example in which an electromagnet 42 is used in place of the piezoelectric vibrator 40 as the vibration excitation means, and a permanent magnet 42 attached to an arm extending behind the ink head 35 is placed between the opposing magnetic poles of the electromagnet 42. The magnet 43 is positioned and the electromagnet 41 has two
Apply AC of 0ON400H2 and stay is3,33
In addition to the zero vibration excitation means that rotates the ink head 35 up and down around the fulcrum of the ink head 35 to vibrate it, a crank mechanism is used to convert the rotation of the motor into linear motion. Note that it is desirable that the vibration angle θ of the ink head 35 be approximately 12°. These are the nozzles of the recording paper 32 and the ink head 35 (air ejection holes 8a in the one shown in FIG. 1).
The standard distance between t-! =main-,-U=O,X... (4)2
This is because it becomes 15 and becomes 0ki12@.

In the case of such an inkjet printer of the present invention, the signal application timing tSfE electric vibrator 40 for ejecting ink droplets to the piezoelectric vibrator 3 of the ink head 35
(or the electromagnet 4j) By synchronizing the period of the voltage applied to the head vibration with respect to K, it becomes possible to form an ink dot tube at a predetermined vertical position.O Also, the voltage applied to the piezoelectric vibrator 40 The carriage 34. Sub-scanning is performed by moving the ink horizontally by 9 degrees 359.

Note that the horizontal transport of the ink head 36, etc. may be continuous instead of a sidewalk, but in that case, the vertical ls drawn by the ink drive (ink drive)
is a slightly oblique K 0. Similar to the inkjet printer of the present invention, a plane scanning printer lamp with the main scanning direction as the vertical direction is conventionally used. It is a device that adds deflection, and has a structural [11MK] 0 Also, it is a multi-head type with multiple heads arranged in parallel in the vertical direction, a wire pin is provided for counting, and dots lined up vertically are printed as -★. There are some, but they still have a complicated structure. In contrast, in the case of the present invention, the 1 Jll construction is simple, and the present invention is not only effective in reducing the weight of the small lid, but also has a low failure rate and stable operation over a long period of time. As such, the inkjet printer according to the present invention f14 is equipped with an on-demand type ink head having two ink chambers, and this ink head is connected to an excitation means for vibrating the ink droplets in a fixed direction Is. Since it is designed to perform scanning, it has become possible to perform flat scanning using an on-demand type ink head, which was previously thought to be practically impossible, and has improved the loading of recording paper, the area around the ink head, etc. An inkjet printer with a simple mechanism can be realized.

[Brief explanation of the drawing]

Figure 1 is a longitudinal sectional view of an ink head with two ink chambers, Figure 2 is a structural diagram of the main parts of a drum scanning type printer,
FIG. 3 is an explanatory diagram of a plane scanning type printer, the fourth factor is an explanatory diagram showing an example of an ink head scanning method, FIG. 5 is an explanatory diagram of an ink head scanning method according to the present invention, and FIG. FIG. 1 is a schematic structural diagram of the circumference of an ink head of an inkjet printer according to the present invention, and FIG. 2 is a schematic structural diagram showing another embodiment of the present invention. 34... Carriage 35... Ink head 40.
... Piezoelectric vibrator 42 ... Electromagnet 43 ... Permanent magnet Patent applicant Noboru Kawano, Patent attorney representing Sanyo Electric Co., Ltd. No. 6 Closed Fig. v

Claims (1)

[Claims] 1. In a plane scanning inkjet printer, 2.
The on-demand ink head 1 has two ink chambers, and is characterized in that a vibrating means for vibrating the ink droplet ejection direction in a specific direction is connected to the core ink. inkjet printer. 2. The inkjet printer according to claim 1, wherein the ink head is pivotally supported so as to be rotatable in the direction of the object. 3. When the vibration excitation means is a piezoelectric vibrator: i ¥1: The inkjet printer according to item 1 or 2 of the desired range. An inkjet printer according to claim 1 or 2, wherein the vibration excitation means has a magnetic effect.