JPH05104730A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To prevent a fall of a meniscus caused by the increase of a cap internal pressure by a method wherein when an ink jet recording head is capped, an open/close action of an atmosphere connecting port connecting to a cap is efficiently conducted. CONSTITUTION:When a detected recording head temperature is relatively as high as B deg.C or more, an atmosphere connecting port open/close action is conducted twice after 30sec and 1min in steps F8 and F9. When a relatively low recording head temperature from C to B deg.C is detected, an atmosphere connecting port open/close action is conducted after 1min. In this manner, an open/close action is controlled in an optimum manner in accordance with a recording head temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus used in a printer, a facsimile or the like, and more particularly to an ink jet recording apparatus having a recovery system for keeping good ink ejection of a recording head by sucking ink.

[0002]

2. Description of the Related Art A recording device used in a printer, a facsimile or the like is a device for recording on a sheet (recording medium such as paper or plastic thin plate) by driving a recording head based on a recording data signal. There are various recording methods such as a thermal method and a wire dot method, and an ink jet method is one of them.

The ink jet type recording apparatus is configured to perform recording by ejecting ink from a plurality of ejection openings provided on the front surface of the recording head based on a recording data signal and fixing the ink on a sheet. At this time, in order to promote fixing of the ink to the sheet (a state in which water is evaporated and dried), for example, a fixing device in which heating is performed from the back surface of the sheet by a surface heater may be used.

FIG. 1 is a vertical sectional view showing an example of the structure of an ink jet recording apparatus.

In FIG. 1, a recording sheet (recording medium) 1 such as a sheet of paper or a plastic thin plate has the form of a cut sheet, and the recording sheets 1 stacked on the cut sheet feeder are separated one by one from the uppermost layer. It is separated and fed by the cooperation of the claw 2 and the paper feed roller 3. By this feeding, the recording sheet 1 fed between the paper feed roller 4 and the pinch rollers 5 and 5 pressed against the paper feed roller 4 is controlled by controlling the rotation of the paper feed roller 4, and the recording portion ) And is set to a recording start state.

The recording head 6 is an ink jet type recording head, and the recording head 6 is attached to a carriage 7. In the case of an inkjet recording apparatus, a plurality of ink ejection ports are arranged on the front surface (ejection port surface) of the recording head 6 in the vertical direction, that is, in the same direction as the conveyance direction of the recording sheet 1 facing these. The carriage 7 on which the recording head 6 is mounted is main-scanned in the recording digit direction (the direction perpendicular to the recording sheet conveying direction) of the recording sheet 1, and ink is ejected from the recording head 6 for one line accordingly. Record the image. The paper is fed (sub-scanning) every time one line of recording is performed, and the recording is sequentially performed line by line.

A fixing device 8 which functions as a platen and a guide plate for guiding the recording sheet 1 along the sheet feeding path is installed at a position facing the recording head 6. The fixing device 8 is a surface heater having a heater wire (not shown) attached to a sheet metal.

The recording sheet 1 that has passed through the fixing device 8 is provided with a discharge roller 9 arranged on the discharge side thereof and a spur roller 10 provided in a spur roller unit 10 pressed against the discharge roller 9.
It is discharged onto the stacker 11 by a.

Below the recording area, which is the area in which the recording head 6 performs main scanning, a paper pressing plate 12 for pressing the recording sheet 1 against the fixing device 8 is arranged as close as possible to this recording area.

FIG. 2 is a plan view showing a part of the structure and arrangement of the above-mentioned ink jet recording apparatus.

In FIG. 2, clogging of the ink ejection port of the recording head 6 is removed by sucking the ink to a position different from the platen 8 at a position facing the recording head 6, and ink is ejected well. A recovery system 13 for recovering the state is provided. The recovery system 13 is connected to the recording head 6 (capping) for sucking ink (capping) 3a, and the suctioned ink is recovered by the recovery system 13.
Is provided with an ink discharge port 13b for discharging the ink to the outside of the tube 1 and the ink is connected to the ink discharge port 13b.
4 is led to the waste ink tank 15. Suction port 1
3a is used not only for ink suction as described above, but also for preventing evaporation of ink moisture in the discharge port by blocking the discharge port from the outside air by capping the ink and for preventing ink thickening. Used. The suction port 13a is provided so as to be movable back and forth with respect to the recording head 6. On the other hand, the recording head 6 is connected with a tube 17 from an ink cartridge 16 that stores ink for supply, and is filled with ink that has been consumed.

FIG. 3 is a schematic view of an ink path of the ink jet recording apparatus.

In FIG. 3, the ink reaches the recording head 6 from the supply ink tank 16 via the supply tube 17. In the capping state of the recording head 6 by the suction port 13a, the recovery system 1 is attached to the ejection port surface of the recording head 6.
The three suction ports (caps) 13a are joined. By driving the pump portion 13c in this state, ink is sucked from each ejection port of the recording head 6, and the ink is discarded from the ink ejection port 13b via the ink ejection tube 14 to the ink ejection tank 15.

When capping with the suction port 13a of the recording head 6 as described above, if capping is performed while the path after the cap 13a is in a completely sealed state, the cap 13a is generated in this path, particularly the cap 13a.
The ink inside the ejection port of the recording head 6 is pushed back into the inside of the head by the increase of the internal pressure of the recording head 6 (meniscus drop).
Occurs, which adversely affects the subsequent ejection of the first ink.

Therefore, the ink passage behind the cap 13a is provided with an atmosphere communication port 13d for adjusting the pressure inside the cap, and the communication port 13d is opened and closed by a valve 13e (shown by a solid line). (Illustrated by broken lines)
It is configured to be able to switch. Normally, at the time of capping, first, the atmosphere communication port 13d is released, and then the cap 13a is capped on the recording head 6, and then the valve 13e of the atmosphere communication port 13d is closed.
The pressure inside the cap can be kept equal to atmospheric pressure. The switching of the valve 13e is performed by the drive unit 1 by the control unit 18.
It is done via 9.

The recording head 6 is provided with a recording head temperature detecting means (thermistor) 20 so that the temperature can be controlled when recording is controlled.

[0017]

However, in an ink jet recording apparatus, the temperature of the entire recording head becomes relatively high due to the heat generated by the ink ejection when generally performing continuous recording. When capping is performed in such a case, in the conventional device, the air communication port is kept closed during capping, so the air in the cap sealed by the heat of the recording head, which is relatively hot, expands and recording is performed. The ink in the ejection port of the head is pressurized. As a result, the meniscus may be dropped.

In order to prevent the above-mentioned problem, it has been proposed to open the atmosphere communication port after capping, for example, after one minute has passed. However, the operation is wasteful or effective depending on the recording amount and the ambient temperature. There were times when there was no.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to detect the temperature of a recording head after recording and to detect the temperature of the recording head, for example, and to communicate with the atmosphere through the atmosphere after capping. By controlling the presence / absence of opening / closing operation of the device, the time until the opening / closing operation, the duration of the open state, etc. An object of the present invention is to provide an ink jet recording apparatus that can perform the operation.

[0020]

Therefore, according to the present invention,
In an inkjet recording apparatus for recording by ejecting ink onto a recording medium, a recording head having an ejection port for ejecting ink from the ejection port, and an amount corresponding to the temperature of the recording head are detected. Detection means for
A cap for covering the ejection port by contacting the recording head, a communication member for communicating the inside of the coating of the cap with the atmosphere, and opening and closing operations of the atmosphere communication port of the communication member. When the cap contacts the recording head and covers the ejection port, the opening and closing operations by the opening and closing unit are controlled according to the amount detected by the detecting unit. And a control means.

[0021]

According to the above construction, the amount corresponding to the recording head temperature is detected, and the opening / closing of the atmosphere communication port after capping of the cap is controlled according to the detected amount. Thus, when the temperature of the recording head is relatively high and the pressure inside the cap rises, the atmosphere communication port can be opened early to reduce the internal pressure.

[0022]

Embodiments of the present invention will now be described in detail with reference to the drawings.

The ink jet recording apparatus of this example is shown in FIG.
The configurations shown in 2 and 3 can be adopted. However,
The control unit 18 shown in FIG. 3 has a ROM storing the processing procedure shown in FIG. 4 and a RAM used as a work area for the processing.

FIG. 4 is a flow chart of the capping operation control after recording in the ink jet recording apparatus showing one embodiment of the present invention. The process of this example will be described below with reference to FIG.

In FIG. 4, when recording is completed (step F1), the temperature T of the recording head 6 is detected by the thermistor 20 provided in the recording head 6 (step F1).
2) The suction port 13a is operated to cap the ejection port surface of the recording head 6 (step F3). Next, it is judged whether or not the temperature T detected in step F2 is a relatively high temperature A ° C. or higher at which there is a possibility of causing failure or destruction of the recording head 6 (step F4). This operation is stopped by displaying an alarm notifying a temperature abnormality (step F7), and when the recording head temperature is lower than A ° C., the process proceeds to the next step F5.

Here, the meniscus drop due to the expansion of air in the cap closed by the capping is 1
The lower limit temperature that occurs within minutes is B ° C, and the upper limit temperature that does not cause meniscus drop regardless of time is C
If the temperature T detected in step F2 is B ° C. or higher and lower than A ° C. (step F5), the atmosphere communication port 13d is opened / closed after 30 seconds, which is a relatively short time after capping. (Step F8), then 1
By opening and closing the atmosphere communication port 13d again after a minute (step F9), the pressure in the cap is adjusted to prevent the meniscus from dropping.

If the temperature T of the head is relatively low and lower than B ° C. and higher than C ° C. (step F6), step F9
After 1 minute, only the opening / closing operation of the atmosphere communication port 13d is performed to prevent the meniscus from dropping. Further, when the temperature T of the recording head 6 is lower than C ° C., it is not necessary to open / close the atmosphere communication port, so the operation is ended as it is and the recording standby state is set (step F10).

The opening / closing operation of the atmosphere communication port performed in steps F8 and F9 is the operation of opening the atmosphere communication port 13d and then closing the atmosphere communication port 13d after a predetermined time (about 200 msec in this example). Say.

The present invention is not limited to the above embodiment.

That is, in the above-mentioned embodiment, the time until the atmosphere communication port is opened and the number of times the atmosphere communication port is opened (including 0 times) are changed depending on the temperature. For example, when the temperature is high, the atmosphere communication in the opening / closing operation is changed. It is also possible to control the opening / closing time according to the detected temperature by, for example, lengthening the above predetermined time for opening the mouth and shortening it when not so high.

Further, in the above-mentioned embodiment, the opening / closing operation of the atmosphere communication port is controlled by the temperature of the recording head, but since the temperature of the recording head has a correlation with the recording amount, the number of characters recorded or The same effect can be obtained by controlling the opening / closing operation of the atmosphere communication port according to the number of characters or the number of ejection pulses, etc.

Further, in the above example, the recording operation time (time from capping to capping) may be used instead of the number of characters to be recorded.

In addition, it goes without saying that the temperature range that serves as a criterion for the opening / closing operation is not limited to the above example, and is set according to the specifications of the recording head.

(Others) The present invention is particularly provided with means for generating thermal energy as energy used for ejecting ink (for example, an electrothermal converter or a laser beam) even in the ink jet recording system. The present invention provides excellent effects in a recording head and a recording apparatus of the type in which the thermal energy causes a change in ink state. This is because such a system can achieve high density recording and high definition recording.

Regarding the typical structure and principle thereof, see, for example, US Pat. No. 4,723,129 and US Pat. No. 4,740.
What is done using the basic principles disclosed in 796 is preferred. This method is a so-called on-demand type,
It can be applied to any of the continuous type, but especially in the case of the on-demand type, it can be applied to the sheet holding the liquid (ink) or the electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal corresponding to the recorded information and giving a rapid temperature rise exceeding nucleate boiling, heat energy is generated in the electrothermal converter, and film boiling is caused on the heat acting surface of the recording head. Liquid (ink) corresponding to this drive signal as a result
This is effective because bubbles can be formed inside. Due to the growth and contraction of the bubbles, liquid (ink) is ejected through the ejection openings to form at least one droplet. It is more preferable to make this drive signal into a pulse shape, because the bubble growth and contraction are immediately and appropriately performed, so that the ejection of the liquid (ink) with excellent responsiveness can be achieved. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. If the conditions described in US Pat. No. 4,313,124 of the invention relating to the rate of temperature rise on the heat acting surface are adopted, more excellent recording can be performed.

As the constitution of the recording head, in addition to the combination constitution of the ejection port, the liquid passage, and the electrothermal converter (the linear liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned respective specifications. US Pat. No. 4,558,333, US Pat. No. 4,558,333, which discloses a configuration in which a heat acting portion is arranged in a bending region.
The configuration using the specification of No. 59600 is also included in the present invention. In addition, Japanese Unexamined Patent Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of the electrothermal converter for a plurality of electrothermal converters, and an opening for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration corresponding to the ejection portion is disclosed in Japanese Patent Laid-Open No. 59-138461. That is, according to the present invention, recording can be surely and efficiently performed regardless of the form of the recording head.

Further, the present invention can be effectively applied to a full line type recording head having a length corresponding to the maximum width of a recording medium which can be recorded by the recording apparatus. Such a recording head may have a configuration that satisfies the length by a combination of a plurality of recording heads or a configuration as one recording head integrally formed.

In addition, even in the case of the serial type as in the above example, the recording head fixed to the main body of the apparatus, or the electrical connection to the main body of the apparatus or the ink from the main body of the apparatus by being attached to the main body of the apparatus. The present invention is also effective when a replaceable chip type recording head that can be supplied or a cartridge type recording head in which an ink tank is integrally provided in the recording head itself is used.

Further, as the constitution of the recording apparatus of the present invention, it is preferable to add ejection recovery means of the recording head, preliminary auxiliary means and the like because the effects of the present invention can be further stabilized. Specifically, heating is performed by using a capping means, a cleaning means, a pressure or suction means for the recording head, an electrothermal converter or a heating element other than this, or a combination thereof. Examples thereof include a preliminary heating unit for performing the discharge and a preliminary discharge unit for performing discharge different from the recording.

Regarding the type or number of recording heads to be mounted, for example, only one is provided corresponding to a single color ink, or a plurality of inks having different recording colors and densities are supported. A plurality of pieces may be provided. That is, for example, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, but may be either integrally formed of the recording heads or a combination of a plurality of them. The present invention is also very effective for an apparatus provided with at least one of full-color recording modes by color mixing.

In addition, in the above-described embodiments of the present invention, the ink is described as a liquid, but an ink that solidifies at room temperature or lower and that softens or liquefies at room temperature may be used. Or, in the inkjet method, it is common to adjust the temperature of the ink itself within the range of 30 ° C. or higher and 70 ° C. or lower to control the temperature so that the viscosity of the ink is within the stable ejection range. At times, a liquid ink may be used. In addition, the temperature rise due to thermal energy is positively prevented by using it as the energy for changing the state of the ink from the solid state to the liquid state, or in order to prevent the evaporation of the ink, it is solidified and heated in a standing state. You may use the ink liquefied by. In any case, by applying heat energy such as ink that is liquefied by applying heat energy according to the recording signal and liquid ink is ejected, or that begins to solidify when it reaches the recording medium. The present invention can be applied to the case where an ink having a property of being liquefied for the first time is used. In this case, the ink is
JP 54-56847 A or JP 60-7.
As described in Japanese Patent No. 1260, it may be configured to face the electrothermal converter in a state of being held as a liquid or a solid in the concave portion or the through hole of the porous sheet. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, as the form of the ink jet recording apparatus of the present invention, besides the one used as an image output terminal of information processing equipment such as a computer, a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmission / reception function It may be in a form or the like.

[0043]

As is apparent from the above description, according to the present invention, the amount corresponding to the recording head temperature is detected, and the opening / closing of the atmosphere communication port after capping of the cap is controlled according to the detected amount. It Thus, when the temperature of the recording head is relatively high and the pressure inside the cap rises, the atmosphere communication port can be opened early to reduce the internal pressure.

As a result, it is possible to effectively perform the opening / closing operation of the atmosphere communication port, and prevent the meniscus of the recording head from falling off, and perform good recording.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an example of the configuration of an inkjet recording apparatus.

2 is a configuration of the inkjet recording apparatus shown in FIG.
It is a top view which shows a part of arrangement | positioning.

FIG. 3 is a schematic view of an ink path of the inkjet recording apparatus shown in FIG.

FIG. 4 is a flowchart of capping operation control after recording in the inkjet recording apparatus according to the embodiment of the present invention.

[Explanation of symbols]

 6 Recording Head 13 Recovery System 13a Suction Port (Cap) 13d Atmosphere Communication Port 13e Opening Valve 18 Control Section 20 Thermistor

Claims (4)

[Claims] 1. An ink jet recording apparatus for recording by ejecting ink to a recording medium, the recording head having an ejection port for ejecting ink from the ejection port, and corresponding to the temperature of the recording head. The detection means for detecting the amount of discharge, a cap for covering the ejection port by contacting the recording head, a communication member for communicating the inside of the coating of the cap with the atmosphere, and the communication member. An opening / closing means for performing opening and closing operations of the atmosphere communication port of the member; and the opening according to the amount detected by the detection means when the cap contacts the recording head to cover the ejection port. An inkjet recording apparatus comprising: a control unit that controls the opening and closing operations of the opening and closing unit. 2. The ink jet recording apparatus according to claim 1, wherein the detection unit detects the temperature itself of the recording head as the detected amount. 3. The ink jet recording apparatus according to claim 2, wherein the control unit controls the number of times of opening and closing operations by the opening / closing unit according to the temperature detected by the detection unit. 4. The recording head according to claim 1, wherein the recording head uses the thermal energy to generate bubbles in the ink and ejects the ink based on the generation of the bubbles. Inkjet recording device.