JPH05330078A - Ink jet recording method and apparatus - Google Patents

Abstract

PURPOSE:To obtain the high emitting reliability of ink without lowering the throughput of image output. CONSTITUTION:Pulse signals P21, P22 having a specified pulse width are usually used as the emission signals applied to the heaters of nozzles in order to emit ink liquid droplets and, when emission is resumed after emission is interrupted for a specified time t1 or more, a pulse signal P23 having large pulse voltage is used as an emission signal is used to increase the supply energy to the heaters.

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 method and an ink jet recording apparatus.

[0002]

2. Description of the Related Art Ink jet recording apparatuses record characters and figures by ejecting ink as minute droplets from nozzles, and are excellent as means for outputting high-definition images and means for high-speed printing. Have advantages.

However, in the recording head of such an ink jet recording apparatus, the volatile components in the ink evaporate from the orifices, the viscosity of the ink in the nozzles increases, and the ejection speed of the ink droplets decreases, resulting in image deterioration. In some cases, discharge defects such as wobbling and non-discharge may occur. In particular,
In the case of an inkjet recording head that generates bubbles in the ink on the heater by heat energy of a heat generating member (hereinafter referred to as a heater) arranged in the nozzle to eject the ink as minute droplets, Because the bubble formation conditions will change due to the change,
The effect of evaporation of the volatile components in the ink on the ejection of droplets is large.

In order to solve such a problem, there has been proposed a sequence for ejecting droplets not used for recording, that is, a so-called pre-ejection sequence during standby or before or after printing operation of the ink jet recording head. ,
For example, a method of moving an ink jet recording head to a predetermined position outside the recording operation range to perform preliminary ejection (Japanese Patent Laid-Open No. Sho 5)
No. 4-99928), a method of performing preliminary ejection on a recording material at predetermined time intervals (Japanese Patent Laid-Open No. 55-139269), and the like. Further, as a specific method of preliminary ejection in the thermal ink jet recording head using the above-mentioned heater, there is a method of performing preliminary ejection and preliminary heating by a heater (Japanese Patent Laid-Open No. 61-146552),
The present applicant has already proposed a method of performing preliminary ejection with a larger thermal energy than during recording (Japanese Patent Laid-Open No. 61-146556).

[0005]

However, the above-mentioned JP-A-54-9928 and JP-A-61-1446552 are mentioned above.
The methods disclosed in Japanese Patent Laid-Open No. 61-146556 and Japanese Patent Laid-Open No. 61-146556 all involve an operation of moving the recording head to a predetermined position outside the recording operation range. For example, in the case of a serial type ink jet recording apparatus that performs recording by scanning a carriage 909 having an ink jet recording head 911 as shown in FIG. 10, in order to perform preliminary ejection during the printing operation, the printing operation is temporarily performed. The carriage 909 must be interrupted and moved to the position of the recovery device 910 that performs preliminary ejection. Therefore, there is a problem that the throughput of image output is reduced.

Further, in the case of the method described in Japanese Patent Laid-Open No. 55-139269, especially for a white recording material,
When performing highlight printing with a low average usage frequency of nozzles using ink droplets of low lightness such as black, stains due to preliminary ejection become relatively conspicuous depending on the image to be recorded. There was a problem.

An object of the present invention is to provide an ink jet recording method and an ink jet recording apparatus which can solve the above-mentioned conventional problems and can obtain high ink ejection reliability without lowering the throughput of image output. is there.

[0008]

According to the ink jet recording method of the present invention, a plurality of orifices for ejecting ink droplets, a plurality of nozzles communicating with each of the orifices, and each of the nozzles are provided. An inkjet recording head having a plurality of ejection means for ejecting ink droplets is used to supply ejection energy necessary for ejecting ink droplets to the ejection means of the recording head to perform recording. In the inkjet recording method to be performed, when a nozzle that has not ejected ink droplets for a predetermined time or longer during operation of the recording head restarts ejection of ink droplets, at least the ejection means of the nozzles The ejection energy initially supplied is equal to the total amount of energy or unit time than the ejection energy normally supplied to the ejection means. Characterized by increasing the amount of energy.

The ink jet recording apparatus of the present invention includes a plurality of orifices for ejecting ink droplets, a plurality of nozzles communicating with each of the orifices, and ink droplets provided in each of the nozzles. An inkjet recording head having a plurality of ejection means for ejecting ink; an ejection energy supply means for supplying ejection energy necessary for ejecting ink droplets to the ejection means of the recording head; and the recording head. In an inkjet recording apparatus including a unit that relatively moves a recording medium, the ejection energy supply unit is a nozzle in which ink droplets have not been ejected for a predetermined time or more during a recording operation of the recording head. When it restarts the ejection of ink droplets, the ejection energy at least initially supplied to the ejection means is And characterized in that the at increasing the energy per total energy or unit time than the discharge energy supplied to the discharge means.

[0010]

According to the present invention, no special mechanism, that is, a mechanical structure for performing a preliminary ejection operation or the like is required, non-ejection of ink droplets is prevented, and high ejection reliability is obtained. Further, according to the present invention, the preliminary ejection operation is performed in order to prevent the non-ejection of the droplets only by changing the ejection condition of the droplets of the ink actually used for printing without performing the preliminary ejection operation during recording. The throughput of image output does not decrease as in the case of

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 5 are views for explaining the first embodiment of the present invention. This embodiment is based on FIG.
It is an application example to a serial type ink jet recording apparatus as shown in FIG.

First, the ink jet recording head used in this embodiment is, as shown in FIG. 1, provided on a substrate 102 on which a heater 101 and electrode wiring (not shown) for sending an electric signal to the heater 101 are formed. It is configured by arranging a predetermined number of nozzle partition walls 103 at a predetermined interval with a partition wall 105 forming a liquid chamber, and further joining a top plate 104 having a supply port 106. Therefore, the portion surrounded by the nozzle partition 103, the substrate 102, and the top plate 104 serves as a nozzle, and ink is supplied to the nozzle from the supply port 106 through the common liquid chamber 107. In addition, when a discharge signal is applied to the heater 101 through the electrode wiring, the heater 101 generates heat and the heater 101
Bubbles are generated in the upper ink due to film boiling, and minute droplets of the ink are ejected from the orifice 108.

FIG. 2 shows a schematic circuit configuration of the control system of this embodiment.

In this figure, the main controller 10
An image data signal 13 is received from a host computer 1014 such as an image reader and stored in a frame memory 1015 for a buffer in units of one frame. During recording, the main controller 1013 is the motor driver A
The carriage feed motor 1016 is driven and controlled through the motor driver B, and the paper feed motor 1017 is driven and controlled through the motor driver B. Also, the main controller 1
Reference numeral 013 controls the ejection signal of the inkjet recording head 1011 via the driver controller 1018 and the head driver 1019 based on the image data read from the frame memory 1015 at the timing described later.

First, a comparative example with the present invention is shown in FIG. This FIG. 3 shows one nozzle N in the inkjet recording head.
It is explanatory drawing of the application timing of the discharge signal with respect to the heater 101 arrange | positioned at i.

As shown in FIG.
In synchronization with the timing signals S21, S22, etc. of (a),
The ejection signals P21, P22, etc. of FIG. 3B are applied.
In FIG. 3A, the ejection signals P21, P22, and P2
To the first timing signal corresponding to S3, reference symbols S21 and S2
2, and S23. Conventionally, when a droplet of ink is ejected by the application of the ejection signal P21, the ejection of the droplet from the nozzle Ni is temporarily interrupted, and the ejection is restarted after a relatively long time t1, the ejection is restarted. As the ejection signal P23 at that time, a pulse signal having the same shape as the normal ejection signal P22 and the like was used. However, when the ejection interruption time t1 is long and during the time t1, the ink in the nozzle is thickened or deteriorated due to the evaporation of the volatile component of the ink from the orifice, a normal pulse signal is generated as the ejection signal P23. There is a possibility that the ink droplets may not be ejected even when the voltage is applied.

Therefore, in the present invention, as shown in FIG.
As the ejection signal P23 applied after the interruption time t1 has passed,
The pulse voltage is larger than the normal ejection signals P21, P22, etc., and the temporal magnitude of the pulse (hereinafter, “pulse width”).
Uses a small pulse signal. Therefore, the discharge signal P23 supplies more energy to the heater 101 per unit time than the normal discharge signal P21 and the like, and by applying the discharge signal P23, a large bubble pressure is generated instantaneously. However, the ink in the nozzle gets a larger kinetic energy. As a result, it is possible to eject droplets as the viscosity of the ink in the nozzle increases.

By the way, the first and second timing signals are generated by the main controller 1013 in synchronism with each other, and based on these timing signals, the main controller 1013 heats the ejection signal at the timing as described above. 101 will be applied.

The following Table 1 shows the orifice area S ₀ = 160 μ
Results of an ejection test under the following different conditions 1 and 2 using an ink jet recording head having a surface area of m ² and a heater 101 having a surface area S _H = 400 μm ^{2 and} an ink having the following composition are shown. Condition 1 uses the pulse signal P41 of FIG. 5A as the normal ejection signals P21 and P22 and the ejection signal P23 when the ejection is restarted. Condition 2 is the normal ejection signal P2
The pulse signal P41 of FIG. 5 (a) is used as 1 and P22, and FIG. 5 (b) is used as the ejection signal P23 when the ejection is restarted.
Pulse signal P42 is used.

Ink composition: Dye (CI.FB2) 3.0% by weight Diethylene glycol 30.0% by weight Ethanol 3.0% by weight

[0022]

[Table 1]

Here, in the ink jet recording head used in the above test, when the pulse voltage Vh as the ejection signal is kept constant and the pulse width tw is increased, the minimum pulse width at which the droplet starts to eject, that is, Threshold pulse width t
w _th is tw _th = 1.9 μsec when Vh = 8.6 v
Is. On the other hand, the pulse widths of the ejection signals P21 and P22 in FIGS. 4A and 4B are 125% and 168% of the threshold pulse width tw _th , respectively, and droplets are ejected by these ejection signals. Will be done. Further, the amount of energy supplied to the heater 101 by the signal P22 having a large pulse width is larger than that of the signal P21 having a small pulse width.

As is clear from Table 1, condition 2 is condition 1
Compared with the above, the droplets can be ejected even after the ejection is interrupted for a longer time, and as in the method of the present invention, by supplying a larger amount of energy to the heater 101 per unit time when the ejection is restarted, the droplets are not ejected. It can be seen that the ejection can be prevented and the reliability of the ejection can be secured.

From the results shown in Table 1, it is also possible to apply a signal that supplies a larger amount of energy per unit time, such as the pulse signal P42 shown in FIG. 5B, even during normal ejection. However, in the ink jet recording head, for example, when an ejection signal having a large pulse voltage Vh is applied to continuously apply a large amount of energy to the heater 101 for a short time, the heater 101 is greatly damaged by thermal stress. As a result, the life of the heater may be significantly reduced. On the other hand, as in the above-described embodiment, during normal ejection, the droplets are ejected by applying energy to the heater 101 to the extent that a predetermined heater life can be maintained, while the ejection of droplets takes a predetermined time t1. Only when the discharge is restarted after the above interruption, a large amount of energy is supplied to the heater 101 a very small number of times (once in the above-described embodiment), so that the life of the heater is not significantly reduced.

As described above, according to the present embodiment, good droplets can be ejected when the ejection is resumed after the interruption of the ejection without performing the conventionally known preliminary ejection, and to the heater 101. There is almost no load such as heat stress.

In this embodiment, the pulse signal P42 for supplying the heater 101 with energy larger than that in the normal ejection is applied only when the first droplet is ejected after the ejection is restarted. Accordingly, the pulse signal P42 may be applied at the predetermined number of times of ejection after the ejection is restarted.

Further, the pulse signal P42 may be continuously applied for a predetermined time after the restart of ejection.

(Other Embodiments) In the above-described embodiment, the discharge signal having a larger amount of energy supplied per unit time is applied at the time of discharging the droplet than at the time of normal discharging, but the effects of the present invention are as follows. It can also be obtained by applying a discharge signal having a larger total amount of supplied energy when the discharge is restarted than when the normal discharge is performed.

Further, in the ink jet recording head used in the above-mentioned embodiment, when the pulse voltage Vh as the ejection signal is kept constant and the pulse width tw is increased, the minimum pulse width at which the liquid droplet starts to be ejected, that is, Threshold pulse width t
w _th is tw _th = 1.9 μsec when Vh = 8.6 v
Is. On the other hand, the pulse signal P4 of FIG.
1 and the pulse width of the pulse signal P51 of FIG. 6 described later are 125% and 168%, respectively, of tw _th , and by applying these as ejection signals, droplets can be ejected continuously. Further, the amount of energy supplied from the pulse signal P51 to the heater 101 is the pulse signal P4.
Greater than that of 1.

Further, according to the experiment, in the above embodiment, instead of the pulse signal P42 at the time of restarting the ejection, a pulse signal P51 (see FIG. 6) having a pulse width tw larger than the normal pulse signal P41 is applied. Also by this, it was possible to obtain an effect that is substantially the same as that when the pulse signal P42 is used.

Further, when the ejection is restarted, a pulse signal whose supply energy per unit time is larger than that in the normal ejection and the total energy amount itself is larger may be applied.

Furthermore, when the ejection is restarted, a preliminary signal that does not eject droplets may be applied prior to the ejection signal. For example, instead of the pulse signal P42 described above,
You may apply the signal shown in. In these figures, the signals Pr61 and Pr71 are preliminary signals for supplying energy to the heater 101 to the extent that droplets are not ejected by their application, and the signals P61 and P71 are the signals P61 and P71.
This is an ejection signal for supplying sufficient energy for ejecting liquid droplets by the application immediately after the application of r61 and Pr71. Further, the time from the start of application of the preliminary signals Pr61, Pr71 to the start of application of the ejection signals P61, P71 immediately after that is less than several times the pulse width of the ejection signals P61, P71, and at time t1. It is desirable that the time is sufficiently shorter than the above. The preliminary signal raises the temperature around the heater by its application, and increases the power of the bubble on the heater formed by the ejection signal applied immediately after that. It is possible to obtain ejection.

Further, in the above-mentioned embodiment, as the ejection signal applied when the ejection of the droplet is restarted, only one kind of ejection signal different from the ordinary ejection is used.
As shown in FIG. 9, a plurality of types of ejection signals P83, P84, P85, etc. capable of supplying the heater 101 with energy larger than the normal ejection signals P81, P82 when the ejection is restarted after the interruption time t2 of a predetermined time or more elapses. May be selectively used. Note that in the example of FIG. 9, the ejection signal P8 is taken into consideration in consideration of the fact that the ejection becomes easier after the ejection is restarted.
1 to P85 have the same pulse voltage, and the pulse width tw1 of the normal ejection signals P81 and P82 and the pulse width tw of the ejection signals P83, P84, and P85 when the ejection is restarted.
3, tw4 and tw5 have a relationship of tw3 ≧ tw4>
It was set so that tw5> tw1.

When different ejection signals are selected during normal ejection when the ejection is restarted after the ejection is interrupted for a predetermined time t1 or more, the time t1 is appropriately set according to the structure of the ink jet recording head or the ink composition used. Just set it. It should be noted that the present invention is not limited to the numerical values, ink composition, nozzle structure, etc. of the above embodiments. Also,
It is not necessary to limit the specific shapes of the ejection signal and the preliminary signal to pulse waves, and the configurations of the ejection signal and the preliminary signal do not have to be limited to those in the above embodiment.

Furthermore, the present invention is not limited to the above-mentioned ink jet recording head, that is, the ink jet recording head which ejects ink droplets by utilizing the thermal energy of the electrothermal converting element such as the heater 101. It can be applied to the inkjet recording head of.

(Others) The present invention is provided with a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for ejecting ink, particularly 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 straight liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned respective specifications. U.S. Pat. No. 4,558,333, U.S. Pat. No. 44, 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 and 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, in addition to 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 can be used. It may be a form or the like.

[0046]

As is apparent from the above description, according to the present invention, no ejection of ink droplets is required without requiring a special mechanism, that is, a mechanical structure for performing a preliminary ejection operation. Can be prevented and high ejection reliability can be obtained. Further, according to the present invention, the preliminary ejection operation is performed in order to prevent the non-ejection of the droplets only by changing the ejection condition of the droplets of the ink actually used for printing without performing the preliminary ejection operation during recording. The throughput of image output does not decrease as in the case of

[Brief description of drawings]

FIG. 1 is an exploded perspective view for explaining the structure of an inkjet recording head.

FIG. 2 is a schematic circuit configuration diagram of a control system showing an embodiment of the present invention.

FIG. 3 is an explanatory diagram of an application timing of an ejection signal showing a comparative example with the present invention.

FIG. 4 is an explanatory diagram of application timing of an ejection signal as an embodiment of the present invention.

5A and 5B are explanatory diagrams of pulse signals used as the ejection signals of FIG. 4B, respectively.

FIG. 6 is a diagram for explaining another example of a signal used as an ejection signal of the present invention.

FIG. 7 is a diagram for explaining still another example of the signal used as the ejection signal of the present invention.

FIG. 8 is a diagram for explaining still another example of the signal used as the ejection signal of the present invention.

FIG. 9 is an explanatory diagram of application timing of an ejection signal as another embodiment of the present invention.

FIG. 10 is a schematic perspective view of an inkjet recording apparatus.

[Explanation of symbols]

 101 Heater 102 Substrate 103 Nozzle Partition 104 Top Plate 105 Partition 106 Supply Port 107 Common Liquid Chamber 108 Orifice 909 Carriage 910 Recovery Device 911 Inkjet Recording Head

Claims (4)

[Claims] 1. A plurality of orifices for ejecting ink droplets, a plurality of nozzles communicating with each of the orifices, and a plurality of nozzles provided in each of the nozzles for ejecting ink droplets. An inkjet recording head having a discharging means for discharging the ink droplets is supplied to the discharging means of the recording head to discharge ink, thereby performing recording. When the nozzle that has not ejected the ink droplet for a predetermined time or more restarts the ejection of the ink droplet, the ejection energy at least initially supplied to the ejection means of the nozzle is The total energy amount or the energy amount per unit time is made larger than the discharge energy supplied to the means. Jet recording method. 2. The recording head according to claim 1, further comprising, as the ejection unit, an electrothermal conversion element that generates thermal energy that causes film boiling of the ink in order to eject ink droplets. The inkjet recording method described in 1. 3. A plurality of orifices for ejecting ink droplets, a plurality of nozzles communicating with each of the orifices, and a plurality of nozzles provided in each of the nozzles for ejecting ink droplets. An ink jet recording head having an ejection unit for ejecting the ink, an ejection energy supply unit for supplying ejection energy necessary for ejecting ink droplets to the ejection unit of the recording head, and a relative movement between the recording head and the recording medium. In the inkjet recording apparatus, the discharge energy supply unit discharges ink droplets from nozzles in which ink droplets have not been discharged for a predetermined time or more during operation of the recording head. When restarting
An ink jet recording apparatus, characterized in that the ejection energy at least initially supplied to the ejection means of the nozzle is larger than the ejection energy normally supplied to the ejection means in the total energy amount or the energy amount per unit time. .. 4. The recording head according to claim 3, further comprising, as the ejection unit, an electrothermal conversion element that generates thermal energy that causes film boiling of the ink for ejecting ink droplets. The ink jet recording apparatus according to item 1.