JPS63193846A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To enable an ink to be sucked from a liquid passage in a recording head before a non-ejectable condition is generated, by guiding the recording head to a home position at predetermined time intervals and sucking the ink through an ejecting port by a suction device, with a predetermined spacing maintained between the head and a capping means, during recording. CONSTITUTION:A capping means 13 provided at a home position comprises an elastic frame 14 on the side for facing an ink-ejecting surface 3A of a recording head 3. When the head 3 is guided to a position for facing the elastic frame 14 during recording, a predetermined spacing is maintained between the ink- ejecting surface 3A of the head 3 and the elastic frame 14 of the capping means 13. The capping means 13 can be moved in the direction of an arrow (f). When recording operation of a recorder is finished and the head 3 is returned to the home position, the head 3 is so moved that the elastic frame 14 of the capping means 13 makes contact with the ink-ejecting surface 3A of the head 3. Thus, an ink liquid raised in viscosity and bubbles can be sucked out of nozzles by a suction pump 17.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an inkjet recording device, and more particularly to an inkjet recording device provided with a capping means for stably ejecting ink.

[Conventional technology]

In an inkjet recording device that performs recording by selectively ejecting ink from a plurality of ejection ports, a capping means that can be joined to the tip of the liquid path of the head is provided, which tends to cause clogging of the nozzles when the nozzle is not in use. When not recording, the ink ejection surface is joined to the capping means, the recording head is sealed from the surrounding air as if it were covered with a lid, and the space at the joint is filled with ink vapor to maintain saturated vapor pressure. A device has been developed that prevents the ink liquid in the nozzle from drying out and increasing its viscosity.

1, As1-Pl "11-A?p+'ieJ&ff*+
Even if Lf-Fl, AeMr, IJe, +/Fu are used, an increase in the viscosity of the ink is unavoidable in a low humidity environment or when recording is stopped for a long period of time, completely preventing ink failure during recording. It's not enough to do that.

Therefore, in order to solve this inconvenience, suction is forcibly performed through a capping means to bring the joint space into a low pressure state and suck out the ink from the liquid path.
Alternatively, there is an inkjet recording apparatus in which the ink liquid in the nozzles is pressurized automatically or manually by a pump provided on the side of the ink supply system including the recording head, and the ink is discharged from all the nozzles.

[Problem that the invention seeks to solve]

However, just by providing a means for forcibly discharging ink as described above, it is not possible to connect the capping means to the recording head during recording.
Regarding the recording head, especially in the case of a multi-nozzle in which a large number of nozzles, for example 128 nozzles, 256 nozzles, or more, are arranged, this problem may occur because some nozzles eject ink at long intervals. 7
At night, the ink evaporates due to the low humidity environment and becomes highly viscous, making it difficult to eject or causing ejection failure.This tendency is especially true for color inkjet, or when ink liquid with a high dye concentration is used to form a dark image. It occurs noticeably when

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to focus on the above-mentioned problems, and to solve the problems, it is an object of the present invention to suck ink from a liquid path of a recording head before a state where ink is not ejected occurs during recording. An object of the present invention is to provide an inkjet recording device that enables the following.

[Means for solving problems]

In order to achieve this object, the present invention mounts a print head on a carriage, moves the carriage from a home position to a print area, and performs printing by ejecting ink from the ejection ports of the print head. At other times, the discharge port is NM at the home position by capping means.
In the inkjet recording apparatus, the capping means includes a suction device, and during recording, the recording head is guided to the home position at predetermined time intervals, and a predetermined gap is maintained between the capping means and the capping means. It is characterized in that ink is sucked from the ejection port by a suction device.

(Function) According to the inkjet recording apparatus of the present invention, the recording head is guided to the home position at predetermined intervals, and the suction pump performs a suction operation while maintaining a predetermined distance from the capping means. Since the recording head is returned to the position, it is possible to eliminate the situation where good ejection cannot be obtained due to being left undischarged for a long time.

〔Example〕

Embodiments of the present invention will be described in detail and specifically below based on the drawings.

FIG. 1 shows an embodiment of the present invention, where 1 is a roller for recording paper or the like, which is driven by a motor (not shown);
The recording material in the form of continuous paper or cut paper is transferred to the recording head 3.
and the platen roller 1 while being held by a pinch roller (not shown). The recording head 3 is mounted on a carriage 4, and is driven along two guide rails 5A and 5B in the direction S in the figure, during which recording is performed on the recording material. In addition, the carriage 4 is
It is connected to a belt 7 stretched between pulleys 6A and 6B, and is driven by a motor 8 provided coaxially with the pulley 6A.

Further, the recording head 3 in this example is, for example, yellow (Y).
, magenta (M), cyan (C), and black (B
), and each of these recording units has a supply pipe (pipe).
OY, IOM, IOc, and 10B are connected, and ink is supplied to ink tanks IIY, IIM, and 11 from IIB.

Reference numeral 13 is provided at a position facing the ejection part of the head 3 at the home position of the recording head 3, and is 8ffJ in the f direction.

Thus, in the inkjet recording apparatus of this example, when recording is not being performed and ink is not being ejected, the recording head 3 joins with the capping means 13 to shut off the nozzle ejection ports from the outside air and at the same time fill the internal space with ink liquid vapor. The ink liquid in the flow path is prevented from drying, and during printing, printing is performed by reciprocating the printing head 3 in the S direction.

Furthermore, in this example, even during recording as the rad 3 moves toward recording, ink is forcibly ejected as necessary to prevent clogging. In this state, the recording head 3 is guided to a position facing the capping means 13.

That is, in this figure, the capping means 13 provided at the home position is connected to the ink ejection surface 3 of the recording head 3.
An elastic frame 14 is provided on the side facing A, and when the recording head 3 is guided to such a facing position during recording operation as described later, the ink ejection surface 3A of the recording head 3 and the capping A predetermined distance is maintained between the means 13 and the elastic frame 14. Regarding this interval, for example, in the case of an example of an apparatus configured to scan an A1 size recording material in about 8 minutes, 128 nozzles 16 are arranged on the ejection surface 3A at intervals of 63.5 μm. , 1-8 m
/m, and the suction force of the suction pump 17 when performing suction is approximately
~5 m/sec is sufficient. Furthermore, in this figure,
18 is a liquid chamber, 19 is an ink supply pipe, and 20 is a driver for driving the ejection means in the nozzle 16.

Further, as mentioned above, the capping means 13 is movable in the f direction, and when the recording operation by the recording device is completed and the recording pad 3 is returned to the home position, the elastic frame 14 of the capping means 13 is moved. The head 3 may be moved so as to come into contact with the ink ejection surface 3^ of the recording head 3. In this way, the suction pump 17 can suck out the highly viscous ink liquid and air bubbles inside the nozzle.

Next, with reference to FIG. 3, a circuit for controlling preliminary ejection, which is implemented to prevent ejection failure of the print head nozzles, will be explained. Here, 20 is a main control unit (CPU) for recording control.
The main control unit 20 can drive the head driver 21 using a print command signal Sp including color information to eject ink from a selected head nozzle ejection port of the print head 3, and can also drive a carriage control circuit. Main scanning and sub-scanning are performed via 30 and platen l.

31 is a resistor, 32 is a capacitor, and when the power is turned on by a main switch (not shown), the output taken out from the contact between the resistor 31 and the capacitor 32 is sent to the inverter 33.
goes to H" level and is supplied to the OR gate 34. Therefore, the OR outputs of the OR gate 34b1 and others become "H" level.
As a result, the output terminal Q of the flip-flop circuit 35 to the AND gate 36 is maintained at the "H" level.

In such a state, the main controller 20 outputs the recording signal S.
A signal S output to the AND gate 36 at the same time as p
When A becomes H level, the AND output from the AND gate 36 to the preliminary ejection circuit 37 becomes H level, the preliminary ejection circuit 37 drives the carriage motor 8 via the carriage control circuit 30, and the carriage 4 is activated. Return to the predetermined home position.

After the carriage 4 returns to the home position in this manner, a drive signal is further supplied from the circuit 37 to the suction pump 17, and preliminary forced ejection from seven predetermined short-time ejection ports is performed. Note that, until the carriage 4 returns to the home position and the pre-forced ejection for a predetermined period of time is completed, a signal SA is output from the pre-ejection circuit 37 to the main control unit 18 to inhibit the recording operation. When the preliminary ejection described above is completed, the signal ST disappears, and the main control section 20 resumes the printing operation by moving the carriage 4 and selectively ejecting ink from the print head nozzles in response to the signal Sp.

Further, at the same time as the preliminary ejection ends, the completion signal SE is supplied to the timer circuit 38, and the timer circuit 38 starts counting time pulses from that point. At the same time, the flip-flop circuit 35 is reset by the completion signal S6, and the output to the AND gate 36 becomes "L" level.

Therefore, in this state, even if the recording signal +Sp and the signal SA from the main control section 20 to the AND gate 36 go to "H" level, the preliminary ejection circuit 37 is not driven.

Then, when the count value in the timer circuit 38 reaches the set value, the set terminal S of the flip-flop circuit 35 is set to the "H" level via the OR gate 34. Therefore, the signal from the output terminal of the flip-flop circuit 35 to the AND gate 36 is kept at the "H" level, and when the signal SA is generated by the ejection command in the main control section 20, it causes a series of pre-ejection signals to be sent via the pre-ejection circuit 37. Although the ejection operation is performed, the main control unit 20 outputs the recording signal S.
Unless p is output, the AND output from the ant game 36 does not go to the "H" level, and preliminary ejection is not performed, resulting in a waiting state.

The time at which the timer is set as the time interval at which the above-described preliminary ejection is performed may be, for example, about every minute.

Furthermore, although not shown in the drawings, for example, a position detection sensor is provided near the left margin position of the carriage 4, and an AND output is performed using the detection signal from this position detection sensor and the AND output from the AND gate 36 shown in FIG. It is also possible to perform a series of preliminary ejection operations by the preliminary ejection circuit 37 in such a manner as to obtain the following.

In addition, in the above explanation, preliminary ejection was performed by suction at regular intervals, but for example, by detecting the temperature near the print head, it is also possible to perform the preliminary ejection as described above even when the environment becomes low temperature. It is also possible to have it performed.

(Effects of the Invention) As described above, according to the present invention, the recording head is moved to the home position at predetermined intervals during the recording operation, and the ink discharge operation by suction is performed through the capping in a non-contact state. As a result, especially in multi-nozzle heads, nozzles that have not had a chance to eject for a long time will no longer become clogged and stable ejection cannot be obtained. This makes it possible to improve the recording speed.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of the configuration of an inkjet recording apparatus according to the present invention, FIG. 2 is a perspective view showing an outline of a capping means according to the invention, and FIG. 3 is a perspective view showing preliminary ejection of ink by the inkjet recording apparatus according to the present invention. FIG. 2 is a configuration diagram of a circuit for implementation. DESCRIPTION OF SYMBOLS 1... Platen, 3... Recording head, 4... Carriage, 11... Ink tank, 13... Capping means, 16... Nozzle, 17... Suction pump, 20... Main control section, 21... Head driver, 30... Carriage control circuit, 35... Flip-flop circuit, 36... AND gate, 37... Preliminary ejection circuit, 38... Timer circuit.

Claims (1)

[Claims] A recording head is mounted on a carriage, the carriage is moved from a home position to a recording area, and ink is ejected from the ejection ports of the recording head to perform recording, except when performing the recording. In the inkjet recording apparatus, the ejection port is covered by a capping means at the home position, and the capping means includes a suction device, and during the recording, the recording head is moved to the home position at predetermined time intervals. The inkjet recording apparatus is characterized in that the suction device suctions the ink from the ejection port while maintaining a predetermined gap between the ink and the capping means.