JPS61132351A - Ink jet printer - Google Patents

Abstract

PURPOSE:To improve processing speed by providing a clogging detector, in a non-printing region, which is built-in a roller that has a function to protect and restore a printing head, and by permitting a series of actions other than printing without relocating the printing head. CONSTITUTION:A clogging detector 30 is fixed to the exterior by the use of a mounting plate 31, and it does not revolve, regardless of rotation of an eccentric roller 29 at the time of repairing of a clogging. A capping portion 38 of the eccentric roller 29 protrudes as if it covers a nozzle surface with rubber, and by rotation of the eccentric roller 29 a capping is provided for the head surface. And thus, the capping at non-printing time prevents drying of the nozzle surface. At the start of printing, ink is discharged to check a nozzle clogging, and if any clogging is detected, an ink is discharged forcibly from a nozzle of an ink supply means other than the nozzle for a normal printing to remove nozzle clogging. For the above, the eccentric roller 29 is rotated and the remaining ink on the nozzle surface is stuck to the recovery surface.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to an on-demand inkjet printer that ejects ink droplets according to print information, and particularly to an on-demand inkjet printer that increases the processing speed of a series of operations other than printing, and This article relates to an inkjet printer designed to be miniaturized.

Inkjet printers are extremely low-noise, capable of high-speed printing, use inexpensive plain paper, do not require development or fixing, and can record kanji characters, figures, etc.

The print head includes an electromechanical transducer such as a piezoelectric element, and when an electric signal is applied to the piezoelectric element, pressure waves generated within the head are used to eject ink from a nozzle to print.

However, due to the principle of printing, the ink used tends to dry out and cause nozzle clogging, so it is necessary to stabilize the ink particles ejected from the nozzle, and to ensure that it is stable for long-term use and does not clog the nozzle. . Therefore, there is a need for an inkjet printer that satisfies these requirements and is more compact because the device is often placed on a tabletop.

[Conventional technology]

A conventional inkjet printer has an ink supply system, for example, as shown in FIG. It will be done. In addition, a check valve 5 that prevents the ink in the sub tank z from flowing back into the main tank 3 side, a carriage 6 that moves the head 1, and a pump 7 that pressurizes the ink in the sub tank 2.
Equipped with

The head 1 and the sub-tank 2 are integrally constructed as shown in FIG. 5, and the ink in the pressure chamber 8 is driven by a piezoelectric element 9 to pass through a conduction path 10 and eject ink droplets from a nozzle 11. Ink in the pressure chamber 8 is replenished from the sub-tank 2, and ink to the sub-tank 2 is supplied from an intake port 12 connected to the main tank 3.

The sub-tank 2 is a bag inscribed in a case 13, and the amount of ink in the sub-tank 2 is controlled by a detector 14. In addition, 15
is a photo sensor.

Further, since the ink in the nozzle 11 tends to dry and become clogged, a capping mechanism 16 as shown in FIG. 6 is provided to prevent the ink from drying out.

The capping member is a protrusion 17 made of rubber or the like as shown in the figure.
It is configured to cover the nozzle surface at the non-printing position. The head 1 is configured to be movable on a carrier 20 that moves on a carrier shaft 19. 21 indicates paper.

The figure shows the state during the capping operation, in which the head 1 that has finished printing comes into close contact with the protrusion 17 of the capping mechanism 16 in a place other than the printing area, and protects the nozzle 11.

Further, there is a mechanism for moving the head 1 to a position different from the printing area and ejecting ink vigorously from the nozzle 11 to remove clogging in the nozzle portion. Conventionally, as shown in FIG. 7, there is a method of discharging into a pipe 22 that covers the nozzle part including the nozzle 11, and as shown in FIG. There is a method for recovering ink.

The former method requires a drive mechanism that brings the recovery tube 22 into close contact with the nozzle 11 surface without impacting it, and it is difficult to recover the entire amount of ejected ink, resulting in ink remaining on the nozzle 11 surface. Furthermore, the latter method requires electromagnetic drive parts such as the recovery pump 23, making it complicated and requiring a large space. Note that 25 indicates a recovery tank.

Therefore, there is a system in which a collection surface as shown in FIG. 9 is formed by an eccentric roller, and a purge mechanism for recovering from clogging which also has a capping function is miniaturized.

In the figure, an eccentric roller 22 is rotatable by a motor 18, and a capping member 23 is disposed on the eccentric roller 22 to cap the eccentric roller 22 when not printing. The head 1 is movable by a carriage drive mechanism, and when a clog is recovered, it moves to a position shown in the figure that is different from the printing area (see Figure 4), and pressurizes the ink in the sub-tank 2 by driving the pump 7, causing the nozzle 11 to move with force. Eject ink well to remove any clogs.

A collection tank 24 for collecting ink is located below the eccentric roller 22, and the ink is collected along the surface of the eccentric roller 22.

Further, a clogging detector 25 for detecting whether or not the nozzle 11 is clogged is installed between the printing section (the position of the paper 21 in the figure) and the eccentric roller 22 as shown by the dotted line in FIG. and printing is performed.

Inside the box of the clogging detector 25, as shown in FIG. 10, ink particles 26 discharged from the navel 1 fly through the air and detect when they reach the detection electrode 27. The amplifier 28 amplifies and outputs the charging current of the ink particles.

[Problem that the invention seeks to solve]

Conventional inkjet printer functions of capping to prevent clogging, purging to restore clogged nozzles, and clogging detection to detect the presence or absence of clogging required the head 1 to be moved for each operation. . Therefore, there are problems in that it takes time to move the carriage and the processing speed is slow.

Another problem is that the nozzle pitch is small, and in order to satisfy the functions of each operation, precision in each stop position is required, and a large space is required to house the individual units.

Furthermore, the clogging device 25 charges the ink particles 26 and detects the charging current, but since the ink particles 26 are extremely small with a diameter of several tens of μm and have a small amount of charge, it is easy to falsely detect them due to noise ( , there is a problem that it is affected by the position and distance d between the electrode 27 and the nozzle 11.

[Means for solving problems]

The above problem is solved by incorporating the clogging detector inside the roller that has the printing nozzle protection and recovery function, and printing a series of operations other than the nozzle protection, clogging detection, and clogging recovery printing. This problem is solved by the inkjet printer of the present invention, which operates without moving the head.

[Effect]

That is, by having a capping mechanism for protecting the print head and a purge mechanism for recovering a clogged head on the circumference of the eccentric roller, and storing a clogging detector inside the roller, a series of operations other than printing, i.e. The operations of nozzle protection, clogging detection, and clogging recovery can be performed with the print head stopped, without the need to move the print head as in the past. Therefore, there is no time for moving the carriage to move the lid 1 to print for each operation, so the processing speed is high.

Furthermore, since one roller is provided with each function, it is easy to achieve stop position accuracy for each operation, it is easy to satisfy each function, and the space for arranging units for each function is reduced.

Furthermore, since the clogging detector 25 is located inside the eccentric roller and is not affected by the position and distance d between the electrode 25 and the nozzle 11, the detection accuracy can be stabilized.

〔Example〕

Hereinafter, the gist of the present invention will be specifically explained with reference to the drawings.

FIG. 1 and FIG. 2 are cross-sectional views showing one embodiment of the present invention.
The figure shows a state diagram when the clogging detector is placed at the same position as the cap position, Fig. 2 shows a state diagram when the clogging detector is shifted from the cap position, and Fig. 3 is a cross-sectional view of the eccentric roller of the present invention. It is. Note that the same reference numerals throughout the figures indicate the same objects.

In the figure, the eccentric roller 29 of the present invention is replaced by the conventional eccentric roller 22 with capping and purging functions shown in FIG.
A clogging detector 30 is housed inside. That is,
In Fig. 1, the inward recovery surface is formed by an eccentric roller as in the conventional case, and the inside of the eccentric roller which also has a canoping function is made into a cavity, and a jam detector 30 is arranged in the cavity. .The clogging detector 30 is the third
As shown in the figure, it is attached to the outside via a plate 31, and is structured so that it does not rotate even if the eccentric roller 29 rotates when clogging is restored. Note that one of the eccentric rollers 29 is fixed via a fixed shaft 32 and a hair ring 33, and the other is fixed via a housing 34 and a bearing 35, and a boot IJ 36 for rotating the eccentric roller 29 is provided.

1a is the center of the outer circumference of the roller, 1b is the center of the inner circumference of the roller, which is the center of rotation, e is the eccentricity, and 37 is a lead wire.

As shown in FIG. 1, the cap portion 38 of the eccentric roller 29 is made of rubber and protrudes to cover the nozzle surface, caps the head surface by rotation of the eccentric roller 29, and has a groove 39 inside the camp portion 38. Ink droplet 4 from head 1
0 passes through the clogging detector 30. In addition, A
indicates a high temperature member.

Also, Fig. 2 shows the case where the clogging detector 30 and the camp position are shifted, and the difference from Fig. 1 is that the cap part 38 position and the high temperature member A is contained in the camp part, but other things are the same. .

The clogging detector 30 has an electrode 41 and an amplifier (not shown) temporarily mounted on a printed circuit board (see FIG. 10) arranged inside a box, and further includes metal guides 42a and 42b along the inner circumference of the roller.
are provided outside the box, and the tightness of the clogging detector 30 is maintained by the guides 42a and 42b even when the rollers rotate. In addition, since the roller is rotated around 1b, the distance between the electrode 41 and the nozzle of the head 1 is constant, and a small amount of ink charge can be detected, and clogging can be detected with high accuracy.

Furthermore, since the cap portion 38 covers and seals the nozzle surface during non-printing, drying of the nozzle surface can be prevented.

In the non-printing area, before printing, ink is ejected to detect nozzle clogging, and when a clogged nozzle is detected, ink is ejected vigorously from the nozzle using an ink supply means different from normal printing, and the nozzle is clogged. remove. When ejecting ink, the eccentric roller 29 is rotated in synchronization with the natural falling of the residual ink on the nozzle surface, and the gap between the collection surface of the eccentric roller and the nozzle is changed, and the residual ink on the nozzle surface is removed from the collection surface. The ink on the collection surface is transferred to another collection section 2.
4 (see Figure 9).

As mentioned above, by storing the clogging detector inside the roller that has a canoping to protect the print head and a purge mechanism to recover the clogged head on its circumference, it is possible to prevent printing without moving the print head. The processing speed is fast because it can be performed in one area and there is no need to move the carriage and move the print head for each operation as in the conventional method. Moreover, by arranging all the functions in one place, it does not take up space unlike the conventional arrangement of each function individually, so it can be made smaller.

〔Effect of the invention〕

As explained above, according to the present invention, a capping mechanism for protecting the print head and a purge mechanism for recovering a clogged head are installed, and a clogging detector is housed inside the roller, thereby protecting the print head. Processing time is fast because each operation can be performed without moving. Furthermore, since all functions are housed in one place, the device can be made smaller.

[Brief explanation of drawings]

Figures 1 and 2 are cross-sectional views showing one embodiment of the present invention. Figure 1 is a state diagram when the clogging detector is placed at the same position as the cap position, and Figure 2 is a diagram showing the clogging detector at the same position as the cap position. Fig. 3 is a cross-sectional view of the capping roller of the present invention, Fig. 4 is a diagram showing the ink supply system of an inkjet printer, and Fig. 5 shows the integrated head and sub-tank. 6 is a perspective view showing a conventional capping mechanism; FIG. 7 is a perspective view showing a conventional clogging recovery mechanism; FIG. 9 is a perspective view showing a purge mechanism having a conventional capping function; FIG. 10 is a diagram showing the inside of the box of the clogging detector. In the figure, 1a is the center of the outer circumference of the roller, 1h is the center of the 6th roller inside the roller, 29 is an eccentric roller, 30 is a clogging detector, 31 is a mounting plate, 32 is a fixed shaft, 33.35 is a bearing, 34 is a housing , 36 is a pulley, 37 is a leader line, 38 is a cap part, 39 is a groove, 40 is an ink droplet, 41 is an electrode, and 4@! Neg @ Ne7in stem? g

Claims (1)

[Claims] In an inkjet printer equipped with a clogging detector that detects ink droplet ejection from a nozzle and a roller that has a print head nozzle protection and recovery function, the clogging detector is equipped with a roller that has the print head nozzle protection and recovery function. It is built inside and configured to protect the nozzle, detect clogging,
An inkjet printer characterized by performing a series of operations other than printing for clogging recovery without moving the print head.