JPH0631929A - Inkjet recording apparatus - Google Patents

Abstract

PURPOSE:To make correct discharging of ink from an inkjet recording head at all times, by providing means which performs cleaning of the recording head once only when the detecting position of the recording head when the power switch is turned ON is not at a capping position, and one or more seconds afterwards, sucks the ink again. CONSTITUTION:When a home position is detected, the actually moving distance is compared with the distance between the home position and a capping position. If the distances are not agreed, it is so presumed that an inkjet recording head 2 is not capped when the power switch is turned OFF, and therefore a carriage is moved to the capping position and a cleaning operation 2 is conducted. Since the cleaning operation 2 is intended to remove cloggings of a nozzle 21 of the head 2 or the ink having the viscosity increased, the cleaning operation is carried out by a cleaning motor 10 once, and one or more seconds later, solidified components generated when the ink is dried or the viscosity of the ink is increased are turned easy to discharge by the moisture of the ink. Then, a sucking operation is carried out again to completely remove discharging substances.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus.

[0002]

2. Description of the Related Art In general, an ink jet recording apparatus having an ink tank and an ink jet recording head for ejecting ink droplets ejects ink from a nozzle-like ejection port having a narrow tip, thereby performing printing. Due to drying and dust adhering to the discharge port, the discharge port is clogged, and printing defects are likely to occur. Therefore, in order to prevent this, a cleaning device is provided for forcibly flowing the ink into the ink jet recording head by the ink inflow means such as a suction means or a pressure means, and discharging the ink and removing the dry ink and dust. Things have been proposed. Then, the head cleaning operation by such forced ink inflow is performed by a manual operation using a switch provided in the inkjet recording apparatus or a method of injecting ink a fixed number of times immediately after the apparatus is turned on. There is.

[0003]

However, in such a conventional technique, the head cleaning performed after the power is turned on is performed a fixed number of times each time regardless of necessity or non-necessity, so that the ink flow rate increases and, as a result, Ink consumption increases. In addition, this has led to an increase in the size of the waste ink tank for storing the discharged ink,
This has a problem that it also hinders miniaturization of the inkjet recording apparatus.

The present invention solves the above-mentioned problems of the prior art and provides an ink jet recording apparatus capable of always keeping the ink jet recording head in a state in which accurate ink ejection can be performed by efficiently injecting ink into the ink jet recording head. The purpose is to provide.

[0005]

In order to achieve such an object, the present invention provides an ink inflow means for forcibly inflowing ink to an ink jet recording head to perform head cleaning, and an ink inflow means at power-on. An ink jet recording apparatus comprising: a print control unit that drives the unit to perform head cleaning; and a capping unit that protects the ink jet recording head when the power is cut off; and a position detecting unit when the ink jet recording head is turned on. , It is determined whether or not the detected position is at the capping position for protecting the inkjet recording head, and when the head cleaning sequence is changed so that the head cleaning is performed only when it is not at the capping position, the cleaning operation is performed once. After running An interval of at least 1 second, characterized by comprising a means for the suction operation again.

[0006]

According to the present invention, it is determined whether or not the detected position at the time of power-on of the inkjet recording head is the capping position for protecting the inkjet recording head during power-off, and when it is not at the capping position. By performing strong cleaning only on the head, the head cleaning can be effectively performed without consuming unnecessary ink, and the capacity of the discharged ink tank can be suppressed to contribute to downsizing of the inkjet recording apparatus. .

[0007]

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

The ink jet recording apparatus according to the first embodiment has an ink jet recording head 2 as shown in FIG.
And a carriage 3 having a cartridge type head 1 in which an ink tank (not shown) is integrated.
The carriage 3 is connected to a part of a drive belt 4 that transmits the driving force of the drive motor 5 and is movably attached to two guide shafts 6A and 6B arranged in parallel with each other. The driving force of the motor 5 causes the ink jet recording head 2 to reciprocate over the entire width of the recording paper fed from the medium feeding device (not shown) to the platen 7 which is arranged so as to face the ejection surface thereof, to the recording paper. It is configured to record.

As shown in FIG. 2, the ink jet recording head 2 has a plurality of thin pipe-shaped head nozzles 21 for ejecting ink, which are arranged in parallel on the ejection surface facing the recording surface of the recording paper. , An electrothermal converter 2 for giving ejection energy that causes film boiling to ink supplied from an ink tank integrated in the cartridge type head 1.
Two are provided.

Further, in the ink jet recording apparatus of the present embodiment, the position where the ink jet recording head 2 is moved during the head cleaning operation outside the range of the reciprocating motion in the recording operation of the ink jet recording head 2 (in FIG. 1,
At the left end of the guide shaft 6A (hereinafter, referred to as a cleaning position), it is driven by the driving force of the cleaning motor 10 via the electric mechanism 11 so as to face the ejection surface of the inkjet recording head 2.
A head cleaning device 8 is provided as a capping unit that includes a cap member 8A that caps the ejection surface of the inkjet recording head 2.

During the head cleaning operation, the head cleaning device 8 sucks the ink, which is the ink inflow means, in association with the capping of the ejection surface of the ink jet recording head 2 by the cap member 8A to force the ink. Each head nozzle 2
A head cleaning operation for removing the thickened ink in 1 is performed. When the power is turned off, the head cleaning device 8 caps the ink jet recording head 2 to prevent ink from thickening and clogging due to nozzle drying.

Further, on the side surface of the head cleaning device 8, a blade 9 made of silicon rubber as a wiping member is held in a cantilever form by a blade holding member 9A, and the blade 9 is similar to the head cleaning device 8 in the same manner. It operates by the cleaning motor 10 and the transmission mechanism 11, and can be engaged with the ejection surface of the inkjet recording head 2. Thereby, after the head cleaning operation, the blade 9 is projected into the moving path of the inkjet recording head 2, and the condensation operation, the wetness, or the dust on the ejection surface of the inkjet recording head 2 is wiped off with the moving operation of the inkjet recording head 2. It is running out.

Further, in the ink jet recording apparatus of this embodiment, an optical sensor (not shown) is provided on the carriage 3, and when the guide shafts 6A and 6B are moved, the home position detecting member 12 is an optical sensor. The inkjet recording head 2 is moved to the reference position (hereinafter,
It is called Home Position HP. ) Is a position detecting means capable of detecting that there is.

The ink jet recording apparatus receives data such as text information and control commands input from an external host device by a print control means, which will be described later, so that a series of recording operations of text information can be performed according to the received data. Done.

The print control means of the ink jet recording apparatus of this embodiment will be described with reference to FIG.

The print control means 30 shown in FIG.
1, a ROM 32 and a RAM 33 that are storage units, an interface circuit 34 that is integrated with a host device 41 that is an external device, a motor control circuit 35 that drives the drive motor 5, the cleaning motor 10, and a home position sensor, The inkjet recording head 2 includes a head control circuit 36 that drives the electrothermal converter 13 and a cleaning control circuit 37 that drives the head cleaning device 8.

The CPU 31 drives the motor control circuit 35, the head control circuit 36, and the cleaning control circuit 37 in accordance with a program stored in advance in the ROM 32 or a control command input from the host device 41 via the interface circuit 34, Controls the overall operation of the inkjet recording device. In this embodiment,
The CPU 3 is stored in the ROM 32, which is a storage unit set by the above program so that the head cleaning operation is performed when the power of the inkjet recording apparatus is turned on.
In addition to storing a program for operating No. 1, a control table for head cleaning is stored in advance. The RAM 33 is also used as a work area for the CPU 31 during calculation or a temporary storage area for control data or the like input from the host device 41 via the interface circuit 34. Interface circuit 34
Is an interface unit for inputting and outputting control commands and control data from the host device 41 to the inkjet recording apparatus.

According to an instruction from the CPU 31, the motor control circuit 35 drives the drive motor 5 to move the carriage 3 during the recording operation, and drives the motor 10 for head cleaning during the head cleaning operation to perform head cleaning. Capping of the inkjet recording head 2 by the cap member 8A of the device 8 is performed, and when the head cleaning device 8 finishes sucking ink, the blade 9 is projected into the movement path of the inkjet recording head 2.

The head control circuit 36 includes a CPU 31.
The electrothermal converter 13 of the inkjet recording head 2 is driven according to the print data transferred from the head nozzles 21 to eject ink.

FIG. 4 is a flow chart showing the head cleaning operation at power-on according to the present invention. The operation of this embodiment will be described below with reference to the flow chart shown in FIG.

First, when the power is turned on (step S10)
1) Move the carriage (step S102). At this time, by counting the drive pulses applied to the drive motor 5 (step S103), the actually moved distance that is proportional to the number of drive pulses is grasped. When the drive motor 5 is equipped with an encoder for position control, its output pulse may be used.

When the home position HP is detected (step S104), it is compared whether the actually moved distance is the same as the distance between the home position HP and the capping position CP (step S105). If the comparison results match, it is considered that the inkjet recording head 2 was capped even while the power was off, and the carriage is moved to the cupping position (step S10).
6) The cleaning operation 1 which is a normal recovery operation is performed (step S107).

If the comparison result does not match in step S105, the ink jet recording head 2 is not in the capping state when the power is turned off, and it is expected that the ink is dried to increase the viscosity and the nozzles are clogged. After moving to the capping position (step S20
9) The cleaning operation 2 which is a strong recovery operation is performed (step S210).

The cleaning operation 1, which is a normal recovery operation, refers to the case where the cleaning motor 10 is moved only once in the capping state. On the other hand, since the cleaning operation 2 is intended to remove the thickened ink and the clogging of the head nozzle 21 of the inkjet recording head 2 caused by the lack of capping when the power is turned off, the cleaning motor 10 is set to 1 Once for one second or more,
The components fixed by drying or thickening the ink are preferably separated by 1 to 10 seconds, more preferably 1 to 3 seconds.
The water content of the sucked ink makes it easy to discharge. After that, the suction operation is performed again to completely remove the discharged matter. As a result, the cleaning operation can be smoothly performed. The interval of 1 second or more is
This is to make it easier for the ink components that have undergone thickening, etc. to be discharged by the water content of the sucked ink, and not to exceed 10 seconds because the total time required for recording is longer than 10 seconds. It is too long and inefficient.

On the other hand, even when the home position HP is not found in step S104, the carriage 3 is known from the number of drive pulses counted in step S103.
If the moving distance exceeds a certain value, that is, the distance between the capping position CP at the left end of the carriage moving range and the home position HP, the carriage 3 is on the right side of the home position HP when the power is turned on. (Step S205), the driving direction is reversed (step S206). Further, the backward drive is continued (step S207), and the carriage is moved until the home position HP is found (step S208).

In step S208, the home position HP
Is detected in order to correctly move the carriage 3 to the capping position CP with reference to the home position HP. After that, the home position HP is used as a reference position also in a series of print recording operations.

As shown in the subsequent flow chart, when it is determined that the driving direction should be reversed (step S205), naturally, capping was not performed when the power was turned off, so that the carriage 3 was not used.
After moving to the capping position CP (step S20
8), cleaning operation 2 is performed (step S21)
0).

As described above, by detecting the position of the carriage 3 when the power is turned on by the moving distance to the home position HP, it becomes possible to determine whether or not the ink jet recording head 2 is in the capping state. The sequence of cleaning operations can be changed.

As a result, the unnecessary cleaning operation is not performed, and the ink jet recording head can be kept in a good condition while minimizing the ink consumption.

On the other hand, in the previous embodiment, the position of the carriage 3 when the power is turned on is determined by the moving distance to the home position HP. This has the advantage that the capping position CP does not need to have an independent position sensor, but also has the disadvantage that the movement control of the carriage 3 becomes complicated when the power is turned on. Therefore, depending on the configuration conditions of the device, it may be better to have a dedicated position sensor. This point is improved in the second embodiment, which will be described below with reference to FIGS. 1 and 5.

That is, in the second embodiment, a micro switch (not shown) is provided near the left end of the guide shaft 6. The micro switch is arranged to be mechanically turned on by a part of the carriage 3 main body when the carriage 3 is at the capping position CP.

FIG. 5 is a flow chart showing the operation of the second embodiment. The difference from the first embodiment is that the capping position CP is detected by the output of the microswitch.

That is, when the power is first turned on (step S301), it is determined from the output of the microswitch whether the carriage 3 is at the capping position CP (step S302). As a result, when it is in the capping position CP, the cleaning operation 1, which is a normal recovery operation, is performed as in the first embodiment (step S303). If the carriage 3 is not at the capping position CP, the carriage 3 is moved to the capping position CP (steps S305 and S).
306), the cleaning operation 2 is performed (step S30).
7).

As a result, the same effective cleaning for the ink jet recording head 2 as in the case of the first embodiment can be performed without complicating the control program of the print control means 30.

It should be noted that the present invention includes means (for example, an electrothermal converter or a laser beam) for generating heat energy as energy used for ejecting ink, particularly in the ink jet recording system, and the above heat The effect is excellent in a recording head and a recording apparatus of a system that causes a change in ink state by energy. 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,
Although it can be applied to any of the continuous type, in particular, 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 recording 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 in a one-to-one correspondence
It is effective because bubbles can be formed inside. Due to the growth and contraction of the bubbles, the liquid (ink) is ejected through the ejection opening to form at least one droplet. It is more preferable to make this drive signal into a pulse shape because bubbles can be immediately and appropriately grown and contracted, so that liquid (ink) ejection 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, further excellent recording can be performed.

As the constitution of the recording head, in addition to the combination constitution of the discharge 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 structure 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 JP-A-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 ink from the main body of the apparatus is electrically connected to 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 for the recording head, preliminary auxiliary means, etc. because the effects of the present invention can be further stabilized. Specifically, heating is performed by using a capping unit, a cleaning unit, a pressure or suction unit 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 it may be either the recording head is integrally formed or a plurality of combinations may be used. The present invention is also extremely 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 system, it is common to control 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. Sometimes, a liquid ink may be used. In addition, the temperature rise due to thermal energy is positively prevented by using it as the energy of the state change from the solid state of the ink to the liquid state, or in order to prevent the evaporation of the ink, it is solidified and heated in the 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-A-54-56847 or JP-A-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 further a facsimile apparatus having a transmitting / receiving function. It may be a form or the like.

[0044]

As described above with reference to the embodiments shown in the drawings, according to the ink jet recording apparatus of the present invention, whether the detected position of the ink jet recording head when the power is turned on is the capping position or not. Determine whether or not
When changing the sequence so that the head cleaning is performed only when the head is not at the capping position, the cleaning operation is performed once, and then the suction operation is performed again at intervals of 1 second or more. Since the amount can be suppressed and the capacity of the waste ink tank can be reduced, it is possible to contribute to downsizing of the inkjet recording apparatus.

[Brief description of drawings]

FIG. 1 is a perspective view showing an overall configuration of an inkjet recording apparatus according to the present invention.

FIG. 2 is an enlarged perspective view of an inkjet recording head included in the inkjet recording apparatus of the present invention.

FIG. 3 is a block diagram of print control means.

FIG. 4 is a flowchart showing a cleaning operation at power-on in the first embodiment of the present invention.

FIG. 5 is a flow chart showing a cleaning operation at power-on in the second embodiment of the present invention.

[Explanation of symbols]

 1 Cartridge type head 2 Inkjet recording head 3 Carriage 4 Drive belt 5 Drive motor 6A, 6B Guide shaft 7 Platen 8 Head cleaning device 8A Cap member 9 Blade 9A Blade holding member 10 Cleaning motor 11 Transmission mechanism 12 Home position detection member 21 Head nozzle 22 Electrothermal converter 30 Printing control means

Claims (2)

[Claims] 1. An ink inflow means for forcibly inflowing ink into an inkjet recording head to perform head cleaning, a print control means for driving the ink inflow means at the time of power-on to perform head cleaning, and a power supply. An inkjet recording apparatus comprising: a capping unit that protects the inkjet recording head when disconnected; a position detection unit that is provided when the inkjet recording head is turned on; and a detected position is a capping position that protects the inkjet recording head. If the head cleaning sequence is changed so that the head cleaning is performed only when the head is not at the capping position, the cleaning operation is performed once, and then an interval of 1 second or more is set, and the suction operation is performed again. Means to do An ink jet recording apparatus characterized by comprising. 2. The ink jet recording head has an electrothermal converter that generates thermal energy that causes film boiling in the ink, as an energy generating element used to eject the ink. 1. The inkjet recording device according to 1.