JP3247404B2 - Ink jet recording head ejection control method and ink jet recording apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the discharge of an ink jet recording head and an ink jet recording apparatus to which the method can be applied, and more particularly to a method for controlling the discharge of ink such as a discharge amount and a discharge speed.

[0002]

2. Description of the Related Art Conventionally, in an ink jet recording apparatus, in order to minimize the occurrence of density fluctuations and density unevenness in a recorded image or the like, particularly, the speed (landing accuracy) of ink ejected from a recording head and the ejection amount (hereinafter referred to as "ink ejection accuracy"). , This amount is Vd
[P / dot]), various controls have been performed to stabilize it.

[0003] The main methods employed in these controls are:
By adjusting the temperature of the ink (hereinafter referred to as temperature control), it is possible to control the viscosity of the ink, which affects the ejection speed and the ejection amount, and to provide a heating element, and the heat energy generated by the heating element allows the ink to be heated in the ink. In the method in which bubbles are generated and the ink is ejected by the growth of the bubbles, the conditions under which the bubbles are generated and the like are also controlled to stabilize the ejection amount and the like. As a specific configuration for adjusting the ink temperature, a heater for heating the recording head holding the ink (also serving as a dedicated heater or a discharging heater), a temperature sensor for detecting the temperature related to the recording head, Using
There is a configuration in which a temperature detected by a temperature sensor is fed back to a heating amount by a heater. There is also a configuration in which heating by a heater is simply adjusted without feedback of temperature.

[0004] In the above configuration, a heater and a temperature sensor are provided.
There are a case where it is provided near the recording head, for example, on a member constituting the recording head, and a case where it is provided outside the recording head.

As another method for controlling the discharge speed and the discharge amount, or as a method used together with the above-mentioned method, an electrothermal converter (hereinafter, referred to as a heat-generating element) for generating thermal energy in the method of discharging along with the generation of bubbles. In some cases, the amount of generated heat is controlled by changing the pulse width of a single pulse (hereinafter, referred to as a heat pulse) applied to a discharge heater to stabilize the discharge amount or control the discharge speed.

The control modes described above are mainly classified into the following four modes.

1) Always perform head temperature control (external / nearby).

[0008] With temperature feedback.

2) The head temperature is adjusted as needed (external / nearby).

[0010] With temperature feedback.

3) Perform high-temperature head temperature control (higher than ambient temperature). With feedback.

4) Pulse width modulation of a single heat pulse.

[0013]

SUMMARY OF THE INVENTION However, the above 1)
In the above method, the temperature of the print head is always adjusted,
The evaporation of the ink moisture accompanying the heating of the heater is promoted.
As a result, the viscosity of the ink in the ejection ports in the recording head increases,
Deterioration of recording image quality by inducing sticking, resulting in increased deflection or non-ejection in which the ejection direction is deflected, and density changes or uneven density due to the relative increase in dye density in the ink. Was invited.

In addition, as a result of the continuous heating by the heater, a change in the structure of the head and deterioration of members constituting the head are promoted, and this also causes a reduction in the reliability and durability of the recording head. In addition, this method is generally susceptible to changes in environmental temperature and self-heating (temperature rise due to ejection), which may cause variations in ejection volume and ejection speed, resulting in density changes and uneven density. there were.

The second method is a method for adjusting the temperature as needed, and is an improvement of the first method.
For example, in order to perform temperature control after a recording command is input, it is necessary to reach a predetermined temperature in a relatively short time, and a large energy for heating [for example, a heating value (W) of a heater] is required.
Must be given. For this reason, in the temperature control, the width of the temperature ripple may increase and accurate temperature control may not be performed. In such a case, the discharge amount may fluctuate due to the temperature ripple, and density change or density unevenness may occur. Conversely, if an accurate temperature control is to be performed, it is necessary to reduce the applied energy, the time required to reach the target temperature becomes longer, and the waiting time until the start of recording increases.

In the above three methods, the target temperature by the temperature control is made higher than the environmental temperature in order to reduce the influence of the environmental temperature change and the temperature change due to the self-heating. According to this, it is possible to reduce fluctuations in the discharge amount and the discharge speed during low-duty printing. However, during high-duty printing, for example, the temperature rise (self-rise When the temperature is large, the effect of the temperature rise cannot be avoided.

As a method of controlling the temperature, the temperature control outside the recording head can generally reduce the influence of the environmental temperature, but has a poor response to the self-heating, and is affected by the self-heating. It can be said that it is easy.

If the temperature is controlled in the vicinity of the recording head (for example, a heater or a temperature sensor is provided on an aluminum plate as a substrate supporting a heater board provided with a discharge heater), the response is improved, Although effective for raising the temperature, a temperature ripple may occur due to a large heat capacity of the aluminum plate serving as the substrate, and the discharge amount may fluctuate due to the temperature ripple.

Further, a single pulse of the above method 4 (hereinafter referred to as a single pulse)
The pulse width modulation method by a single pulse) is that the control width of the discharge amount and the discharge speed capable of absorbing the fluctuation of the discharge amount and the discharge speed according to the temperature change is small, particularly in the ink jet method of bubble formation, and Since it is difficult to obtain a linear increase in the ejection amount and the ejection speed with the increase in the pulse width and the reproducibility is poor, it is difficult to accurately control the ejection amount and the ejection speed.

By the way, as described above, one of the major factors that hinders the conventional ejection control by temperature control is the self-heating in which the ink in the recording head accumulates heat with the ejection.

For example, if the temperature of the ink changes due to the self-heating of the recording head, the bubble bubbling speed and the refill speed fluctuate. The characteristics may fluctuate and the image may be extremely deteriorated.

In particular, in a full-color image formed by inks of four colors, cyan, magenta, yellow, and black, if even one of the recording heads that ejects these inks has ejection characteristics different from the standard state, for example, The change in the color balance due to the difference in the discharge amount causes a change in color and a decrease in color reproducibility (increase in color difference). Or

Further, even when an image is recorded in a single color, if the recording head fluctuates in the discharge characteristics, the refill frequency is lowered or the discharge is not performed.
Streaks and density fluctuations occur especially in solid printing due to the twist. In addition, if the ejection characteristic causes a shift, the reproducibility of fine lines in an image and the quality of characters deteriorate.

On the other hand, in recent ink jet recording apparatuses, the distance between the recording head and the multi-recording medium depends on the material of the recording medium (plain paper, coated paper, OHP paper, etc.) and the recording method (1-pass, 2-pass, etc.). And the recording speed is changed. As a result, the landing accuracy of the ejected ink may decrease. In such a case, controlling the ejection speed of the ink according to the distance or the recording speed is one of the configurations for improving the landing accuracy.

The present invention has been made on the basis of the above-described viewpoint, and an object of the present invention is to improve the ejection speed and the refill frequency even when the temperature of the recording head changes due to environmental temperature or self-heating. An object of the present invention is to provide a controllable ejection control method for an inkjet recording head and an inkjet recording apparatus.

[0026]

According to the present invention, there is provided:
In a method for controlling the ejection of an ink jet recording head in which a bubble is generated in ink by thermal energy generated by a heating element by application of a drive signal and the ink is ejected in accordance with the generation of the bubble, the drive signal includes causing the ink to be ejected. P ₁ for generating thermal energy without pulse, pulse pause interval P ₂ , and pulse P for ejecting ink
A plurality of pulses including _3, together with the P _{1, P 2,} P ₃ and a signal generated in the order, a predetermined width of pulses determined according to the pulse P ₃ to the ink jet recording head, depending on the temperature of the ink jet recording head, the temperature when in the predetermined temperature range, by modulating the width of pulses P ₁ to relatively preceding one of the plurality of pulses, controls the discharge of the ink together, and the width of the pulse P ₁ to be modulated, the relationship between the width of the pulse P ₂ is characterized in that it is a P _{1 <P 2.}

In addition, bubbles are generated in the ink by the heat energy generated by the heating element by application of the drive signal,
In an inkjet recording apparatus for performing recording by ejecting ink from the recording head, using an inkjet recording head that ejects ink with the generation of the bubble,
The drive signal includes a plurality of pulses including a pulse P ₁ for generating thermal energy without discharging ink, a pulse pause interval P ₂ , and a pulse P ₃ for discharging ink, and P ₁ , P ₂ and P ₃ are signals generated in this order, and the pulse P ₃ is a pulse having a predetermined width determined according to the ink jet recording head.
Depending on the temperature of the ink jet recording head, the temperature when in the predetermined temperature range, by modulating the width of pulses P ₁ to relatively preceding one of the plurality of pulses, controls the discharge of the ink together, wherein said pulse width P ₁ to be modulated, that the relationship between the width of the pulse P ₂ is equipped with drive means, for the pulse is P _{1 <P 2.}

[0028]

According to the above arrangement, the expansion speed of the bubbles generated in the ink can be controlled by modulating the waveform of the preceding signal among the drive signals composed of a plurality of signals. Can be controlled. Further, the temperature of the ink ejected by the modulation of the preceding signal can be locally controlled, whereby the temperature of the ink around the bubble when the bubble contracts can be controlled by controlling the ejection speed and the ejection amount. Can be set low regardless of As a result, the contraction speed can be increased, and the refill frequency can be increased.

[0029]

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

According to the present invention, the temperature of the ink to be ejected, that is, the temperature of the ink near the heating element, is controlled so that the ejection speed and the refill speed of the recording head can be controlled without being affected by the environmental temperature and the self-heating of the recording head. Control. Therefore, in the embodiment described below, it is assumed that the drive signal applied to the heating element for performing one ejection includes a plurality of signals. Then, the temperature of the ink is changed by modulating the waveform of the signal preceding the drive signal, and the ejection speed and the refill speed are controlled.

In the embodiment described below, the drive signal is in the form of a pulse, and this pulse is divided into two pulses to form a plurality of drive signals.

First, the ink temperature control by pulse width modulation of the divided pulse will be described with reference to FIGS.

FIG. 1 is a diagram for explaining a divided pulse according to an embodiment of the present invention.

In FIG. 1, V _OP is the drive voltage, P ₁ is the pulse width of the first pulse of the plurality of divided heat pulses (hereinafter referred to as preheat pulse), P ₂ is the interval time, and P ₃ is the second. It is a pulse width of a pulse (hereinafter, referred to as a main heat pulse). T ₁ , T ₂ , and T ₃ indicate times for determining P ₁ , P ₂ , and P ₃ . The drive voltage V _OP is an electric energy required for an electric heat conversion element (heating element) to which the voltage is applied to generate heat energy in ink in an ink liquid path formed by a heater board and a top plate. The value is determined by the area and resistance of the electrothermal transducer, the film structure, and the liquid path structure of the recording head. The divided pulse width modulation driving method is
P _1, and is to be given sequentially pulse width of P _2, P _3, the pre-heat pulse is a pulse for mainly controlling the ink temperature in the ink passage, the important role of the ejection control of the present invention It is loading. The pre-heat pulse width P ₁ is set to a value such foaming phenomenon does not occur in the ink by thermal energy electrothermal transducer is generated by the application.

The interval time is provided to provide a predetermined time interval so that the preheat pulse and the main heat pulse do not interfere with each other, and to make the temperature distribution of the ink in the ink path uniform. The main heat pulse is caused to foam in the ink in the ink passage is for discharging ink from the discharge port, the area of the width P ₃ is an electrothermal transducer, resistance, film structure and the recording head It is determined by the structure of the ink liquid path.

For example, the operation of the preheat pulse in the recording head having the structure shown in FIGS. 3A and 3B will be described.

FIGS. 3A and 3B are a schematic longitudinal sectional view and a schematic front view, respectively, showing an example of the configuration of a recording head to which the present invention can be applied.

3 (A) and 3 (B), reference numeral 1 denotes an electrothermal converter which generates heat by application of the divided pulse. The electrothermal converter 1 has an electrode for applying the divided pulse to the electrode. It is arranged on the heater board 9 together with the wiring and the like. The heater board 9 is formed of silicon, and is supported by an aluminum plate 11 forming a substrate of a recording head.
Reference numeral 12 denotes a top plate on which a groove for forming an ink path or the like is formed, and the top plate 12 and the heater board 9 (aluminum plate 11).
Are joined to form an ink path 3 and a common liquid chamber 5 for supplying ink thereto. In addition, the top plate 12 is provided with ejection ports 7, and each ejection port 7 has an ink path 3.
Are in communication.

In the recording head shown in FIG. 3, the driving voltage V _OP = 18.0 (V) and the main heat pulse width P
₃ = 4.114 and [.mu.sec], when changing the preheat pulse width P ₁ in the range of 0~3.000 [μsec], the discharge amount as shown in FIG. 4 V _d [ng / dot] and the pre-heat pulse The relationship with the width P ₁ [μsec] is obtained.

FIG. 4 is a diagram showing the dependence of the ejection amount on the pre-heat pulse. Hereinafter, the dependence of the ejection characteristics on the pre-heat pulse will be described using the ejection amount as an example. In the figure,
V ₀ indicates the ejection amount when P ₁ = 0 [μsec], and this value is determined by the head structure shown in FIG. In this connection, V ₀ in this embodiment, V ₀ in the case of the ambient temperature T _R = 25 ℃ =
It was 18.0 [ng / dot].

[0041] As shown in curve a of Figure 4, in accordance with an increase in the pulse width P ₁ of the pre-heat pulse, the ejection amount V _d is increased with a linearity from Pasuru width P ₁ is 0 to P _1LMT In the range where the pulse width P ₁ is larger than P _1LMT , the change loses linearity and saturates and becomes maximum at the pulse width P _1MAX .

[0042] Thus, the range of variation of the ejection amount V _d relative to the change in the pulse width P ₁ until the pulse width P _1LMT showing the linearity is easily control the discharge amount by changing the pulse width P ₁ It is effective as a range that can be performed. _Incidentally , in this embodiment shown by the curve a, P _1LMT = 1.87 (μs), and the discharge amount at this time is V _LMT = 24.0 [ng / do].
t]. The pulse width P _1MAX when the discharge amount V _d is saturated is P _1MAX = 2.1 [μs],
The discharge amount V _{MAX at} this time was 25.5 [ng / dot].

[0043] When the pulse width is greater than the P _1MAX, the discharge amount V _d is smaller than V _MAX. This phenomenon is that when a preheat pulse having a pulse width in the above range is applied, micro bubbling (a state immediately before film boiling) occurs on the electrothermal transducer,
This is because the next main heat pulse is applied before the bubble disappears, and the minute bubble disturbs the bubbling by the main heat pulse, thereby reducing the ejection amount. This region is called a pre-foaming region, and in this region, it becomes difficult to control the discharge amount via a preheat pulse.

If the slope of a straight line indicating the relationship between the discharge amount and the pulse width in the range of P ₁ = 0 to P _1LMT [μs] shown in FIG. 4 is defined as the preheat pulse dependence coefficient, the preheat pulse dependence coefficient is:

[0045]

(Equation 1)

Is as follows. This coefficient K _P is determined by the head structure, driving conditions, physical properties of the ink, and the like irrespective of the temperature. That is, curves b and c in FIG. 4 show the case of another print head, and it can be seen that the discharge characteristics change when the print head is different. As described above, since the upper limit value _P1LMT of the preheat pulse P1 is different when the recording head is different, the ejection control is performed by setting the upper limit value _P1LMT for each recording head as described later. Incidentally, in the recording head and the ink indicated by the curve a in the present embodiment, K _P = 3.209 [ng / μ].
sec · dot].

That is, another factor that determines the ejection amount of the ink jet recording head is the recording head temperature (ink temperature).

FIG. 5 is a diagram showing the temperature dependence of the discharge amount. As shown in curve a of Figure 5, the ejection amount V _d relative to the increase in environmental temperature T _R of the recording head (= head temperature T _H) increases linearly. If the slope of this line is defined as a temperature-dependent coefficient, the temperature-dependent coefficient:

[0049]

(Equation 2)

Is as follows. This coefficient K _T does not depend on the driving conditions, but is determined by the structure of the head, the physical properties of the ink, and the like. FIG.
Also, curves b and c show the cases of other recording heads.
Incidentally, in the recording head of this embodiment, K _T = 0.3 [n]
g / ° C. · dot].

FIG. 2 relates to one embodiment of the present invention and is a diagram for mainly explaining the discharge amount control by pulse width modulation.
The principle of controlling the discharge amount will be described with reference to FIG.

As shown in FIG. 2, the discharge amount control is constituted in the following three modes. That is, according to the temperature T _H of the recording _{head, (1) T H ≦ T} 0 ... discharge amount control by the temperature control _{(2) T 0 <T H} ≦ T L ... discharge amount control by the divided pulse width modulation method (3 ) T _L uncontrolled where by _{<T H <T C ... P} 1 = 0, T H is T _C or more is an area that exceeds the foam limit of the ink jet recording head.

[0053] Thus, in the following head temperature T _H is relatively low T ₀ (for example 25 ° C.) performs the ejection amount by temperature control of the recording head described above, at T ₀ or more relatively high temperature, FIG. The discharge amount is controlled by changing the pulse width of the preheat pulse described in 4 (hereinafter, also referred to as PWM control).

As described above, the manner of controlling the discharge amount in accordance with the head temperature is that in a relatively low temperature region, foaming when heat is applied to the ink becomes unstable due to an increase in ink viscosity. Therefore, the ejection itself may not be performed properly, and therefore, it is difficult to control the ejection amount by pulse width modulation. Therefore, when the head temperature is low, the head temperature is previously set to a predetermined temperature (T ₀ ) by temperature control, whereby the ejection amount is controlled to a constant amount,
When the head temperature is high, the ejection amount is controlled by modulating the preheat pulse at the time of ejection.

The above-mentioned temperature T ₀ is the print head temperature targeted by the temperature control. When the print head is at this temperature, the target discharge amount V
_d0 (for example, 30 [ng / dot]) is obtained. The temperature T _{L at} which the discharge amount control shown in FIG.
Can be set as the temperature corresponding to the control limit discharge amount V _LMT shown in FIG. 4 in the relationship shown in FIG.

The mode (1) corresponds to the temperature control area of FIG. 2 and is for securing a predetermined amount of discharge mainly in a low-temperature environment as described above. The recording head temperature (ink temperature) Is controlled to the target temperature T ₀ by temperature control. As a result, the ejection amount V _d0 when the print head temperature T _H = T ₀ is obtained.

In this embodiment, a relatively low temperature T ₀ = 2 is used in order to minimize the above-mentioned adverse effects due to temperature control (thickening, sticking, and temperature control ripple due to evaporation of ink moisture).
5 ° C. This is because, for example, in a normal use environment, the room temperature is maintained at approximately 20 to 25 ° C., and if the recording head temperature is maintained at approximately this temperature, the above-described adverse effects can be reduced. Further, the pulse width P ₁ of the pre-heat pulse at this time is set to P ₁ = P _1LMT, so that the maximum discharge amount V _LMT is obtained by T _H = 25 ℃. further,
In this embodiment, the control mode of (1), that is, each pulse width at the time of temperature control is P ₁ = 1.87 as shown in FIG.
(Μsec), P ₂ = 2.618 (μsec), P ₃ =
4.114 (μsec) was set. In addition, this state is a state corresponding to 1 in a table shown in FIG.

The control mode (2) corresponds to the pulse width modulation area in FIG. This area is in the relatively high print head temperature by high temperature self heating or environmental temperature is above T ₀ due to the discharge region (for example, 26 ° C. ~ 44 ° C.)
, And the changing the preheat pulse width P ₁ according to the table showing the temperature of the temperature sensor detects Figure 7. FIG. 6 shows each state of the pulse width corresponding to each of the table numbers in FIG. FIG. 8 shows a pulse width modulation sequence at this time. In the case of the recording head of this example, the pulse P ₁
The upper limit P _1LMT of the width of O is indicated by table number 1 in FIG.
A [Hex], that is, the value indicated by 1 in FIG. This upper limit is set by table pointer information as described later.

Hereinafter, referring to the sequence of FIG.
The discharge amount control by pulse width modulation shown in FIG. 2 will be described.

The sequence shown in FIG. 8 is, for example, 20 ms
It is started by an interrupt for each ec. First, in step S81, the printhead temperature is detected. Next, in step S82, the in order to prevent the temperature erroneous detection of by the heat flux or electrical noise entering the temperature sensor, the average value T _n a head temperature of the last three times the head temperature and the temperature detected in step S81 T _H ' Is performed. In the next step S83 compares the = T _n-1 'head temperature T _H to obtain = T _n and the previous' that this average value T _H. Where the difference T _n −
T _n-1 is the predetermined temperature step width [Delta] T, that is, the pulse width P _1, 1 unit pulse width corresponding to the change of the pulse width of each step corresponding to the table number shown in FIG. 7 (0.18
If the discharge amount is kept within a temperature range in which the discharge amount is kept constant (that is, ± ΔT corresponds to the temperature range ± 1 ° C. (2 ° C.) shown in FIG. 7) at step S7.
Pulse width P ₁ at 85 and it is this difference proceeds to step S86 if there is greater than + [Delta] T, by increasing one reference table number of the table of Figure 7, P
₁ was reduced one lowered discharge amount, and if the difference is less than -ΔT proceeds to step S84, the increased discharge amount of P ₁ one raised by lowering one table number, Control is performed such that the discharge amount always becomes a constant amount V _d0 . In the process, in order to prevent the occurrence of density jump reason for the change in the pulse width P ₁ for changing the one unit pulse width to prevent feedback malfunction (temperature sensors erroneous detection, etc.) depending on the temperature change is there.

By performing the above-described control, the discharge amount can be controlled in the range of ± ΔV with respect to the target discharge amount V _{d0 in the} temperature range that can be managed by the table of FIG. The state of the change in the discharge amount changes, for example, as indicated by an arrow a in FIG.

When the variation in the discharge amount falls within this range, the density variation occurring during printing of one sheet is suppressed to about ± 0.02 even in the case of, for example, solid printing with a 100% duty, and for example, serial printing. The occurrence of uneven density and streaks that are remarkable in the method do not pose a problem. When the average number of temperature detections is increased, noise and the like are increased, resulting in a smoother change. On the other hand, in real-time control, detection accuracy is impaired and accurate control cannot be performed. In addition, when the average number of temperature detections is reduced, the temperature is weakened to noise and the like, and a rapid change occurs. On the other hand, in real-time control, the detection accuracy is increased and accurate control is possible.

The control mode (3) corresponds to the non-control area shown in FIG. 2. This temperature range is outside the normal printing range of the recording head and is a range that is not often used. However, for example, when recording is performed with 100% duty, the temperature may rise to this temperature range. In this case, P ₁ = 0 (μsec
As c), recording is performed only with a single main heat pulse, thereby preventing self-heating as much as possible. T _C indicates the operating limit temperature of the head.

In this embodiment, by using the table shown in FIG. 7 and performing the sequence shown in FIG.
Until _H = 46 ° C., Δ V centered on V _d0 = 30 [ng / dot]
The discharge amount can be controlled in a fluctuation range of V = ± 0.3 [ng / dot].

FIG. 9 shows a heater board of a recording head which can be used in the above embodiment. On the heater board,
A temperature sensor, a temperature control heater, a discharge heater, and the like are provided.

FIG. 9 is a schematic top view of a heater board.
In the figure, temperature sensors 20A and 20B are disposed on the left and right sides of an array of a plurality of discharge heaters 1 on a Si substrate 9, respectively. These discharge heater 1 and temperature sensor 20
A and 20B are similarly arranged in a pattern together with the temperature control heaters 30A and 30B arranged on the left and right sides of the heater board, and are collectively formed in a semiconductor process. In this example, as for the temperature detected by the temperature sensor, the average value of the temperatures detected by the temperature sensors 20A and 20B is set as the detected temperature.

FIG. 10 shows an ink jet recording apparatus employing the ejection amount control method of the present invention. This apparatus is a full-color serial type printer having replaceable recording heads corresponding to four color inks of black (Bk), cyan (C), magenta (M), and yellow (Y). The head used in this printer has a resolution of 400 dpi, a driving frequency of 4 KHz, and has 128 ejection ports.

In FIG. 10, C denotes four recording head cartridges corresponding to the respective inks of Y, M, C, and Bk, and the recording head and an ink tank storing ink for supplying ink to the recording head are integrally formed. Is formed. Each recording head cartridge C is detachably mounted on the carriage by a configuration (not shown). The carriage 2 is slidably engaged along the guide shaft 11 and is connected to a part of a drive belt 52 that is moved by a main scanning motor (not shown). As a result, the recording head cartridge C can be moved for scanning along the guide shaft 11. 15,
Reference numerals 16, 17, and 18 denote conveying rollers extending substantially parallel to the guide shaft 11 on the inner side and the lower side in the drawing of the recording area by scanning of the recording head cartridge C. The transport rollers 15, 16 and 17, 18 are driven by a sub-scanning motor (not shown) to transport the recording medium P. The conveyed recording medium P faces the surface of the recording head cartridge C on which the ejection port surface is provided, and forms a recording surface.

A recovery system unit is provided facing a movable area of the cartridge C adjacent to a recording area of the recording head cartridge C. In the recovery unit,
Reference numeral 300 denotes a cap unit provided for each of the plurality of cartridges C having a recording head. The cap unit 300 is slidable in the left-right direction in the figure as the carriage 2 moves, and is movable up and down in the figure. When the carriage 2 is at the home position, the carriage 2 is joined to the recording head and capped. Further, in the recovery system unit, 401 and 402 are a first and a second blade as a wiping member, and 403, respectively.
Is a blade cleaner made of, for example, an absorber for cleaning the first blade 401.

Further, 500 is a cap unit 300
And a pump unit for absorbing ink and the like from the ejection port of the recording head and the vicinity thereof through the recording head.

FIG. 11 is a block diagram showing an example of the configuration of a control system in the ink jet recording apparatus.

Here, reference numeral 800 denotes a controller constituting a main control unit, which executes, for example, a microcomputer 801 for executing the above-described sequence in FIG. 8, a program corresponding to the procedure, a table shown in FIG. A ROM 803 stores pulse voltage values, pulse widths, and other fixed data, and a RAM 805 provided with an area for developing image data, a work area, and the like. 81
Reference numeral 0 denotes a host device (which may be a reader unit for image reading) serving as a supply source of image data.
F) Transmission / reception with the controller via 812.

Reference numeral 820 denotes a power switch 822, a copy switch 824 for instructing the start of recording (copying), and a large recovery switch 826 for instructing activation of large recovery.
, Etc., are a group of switches for receiving a command input by an operator. Reference numeral 830 denotes a sensor group for detecting the state of the apparatus, such as a sensor 832 for detecting the position of the carriage 2 such as a home position and a start position, and a sensor 834 including a leaf switch 530 and used for detecting a pump position.

Reference numeral 840 denotes a head driver for driving the electrothermal transducer of the print head according to print data and the like. Part of the head driver is a temperature heater 30A,
It is also used to drive 30B. Further, the temperature detection values from the temperature sensors 20A and 20B are transmitted to the controller 80.
Enter 0. 850, a main scanning motor for moving the carriage 2 in the main scanning direction (the horizontal direction in FIG. 10);
52 is the driver. A sub-scanning motor 860 is used to convey (sub-scan) a recording medium.

The above-described ink jet recording apparatus has recording head cartridges for four colors of ink, cyan, magenta, yellow, and black, and each of these recording head cartridges has an EEPROM 128 for storing information.
Is provided. The information stored in the ROM 128 is
It is read when the power of the ink jet recording apparatus is turned on.
As the ROM data, a table pointer (hereinafter, also referred to as a table number) of a table storing control conditions of the PWM control is read together with the print head ID number, ink color, driving conditions, head shading (HS), and data. The table pointer is set for each head in accordance with the ejection capacity. In accordance with this table pointer, the main body defining an upper limit value of the width of the preheat pulse P ₁ in the divided pulse width modulation driving method. That is,
In the example shown in FIGS. 6 and 7, and the table pointer (ID) is set, thereby the maximum width of P ₁ "OA"
(1.87 μsec).

Hereinafter, the process of reading the head information stored in the ROM 128 will be briefly described.

First, the printhead-specific I
The D number (serial number) is read, and it is checked whether the value of the serial number is, for example, FFFFH. If the serial number is FFFFH, it is determined that there is a head or an error occurs. If the serial number is not FFFFH, the color information of the head is read. Next, it is checked from the color information whether the head is mounted at the correct position specified for each color. If the head is mounted correctly, the next data is read as it is. Is displayed.

Next, it is checked whether the installed recording head cartridge is new by comparing the serial number of the head with the serial number currently stored in the main body. If the head is not a new head, the head information reading process ends. New long if new header information a head (serial number, color information, the pulse width of the main pulse P _3, the PWM control table pointer, the temperature sensor correction value, the head position correction value, date of manufacture, and other information) Is stored in the RAM 805 in the apparatus, and a flag indicating that a new head is mounted is set. Next, the shading information (HS) of the head is read, and the head information reading process ends.

Next, the setting of the driving conditions of the recording head will be briefly described.

[0080] Here, the driving conditions are those showing a main pulse P ₃ involved in discharging, when the power supply is turned on as described above, ID number, color information as ROM information of the head,
Table pointer of the pulse P ₃ is read as a head driving condition with table pointer concerning pulse P _1. In accordance with this table pointer, the main body defining a main heat pulse P ₃ width of the divided pulse width modulation driving control described later.

For the table pointer information of the pulse P ₃ , the optimum driving conditions for each head are set by previously measuring the ejection characteristics of each head in the head manufacturing process, and stored as information in the ROM 128 of the recording head. deep.

As described above, by reading the table pointer for setting the head drive conditions as the ROM information of the head, it is possible to change the set conditions (drive conditions) on the main body side. Thus, the image quality can be easily stabilized even in the case of the present example using the replaceable recording head.

The table pointer information relating to the preheat pulse is also set in the same manner as the table pointer, and will be described briefly below.

In the head manufacturing process, the discharge amount of each head was measured in advance under standard driving conditions (for example, head temperature: _TH = 2).
Drive voltage in an environment of 5.0 (° C.): V _OP = 18.0 (V)
, P ₁ = 4.87 (μsec) and P ₃ = 4.11
4 (μsec) pulse), and the value is set as a measured ejection amount: _VDM . Next, the standard discharge amount: V _DO = 3
The difference from 0.0 [ng / dot] is calculated as V _DO -V _DM, and a table pointer is set based on this. As described above, the upper limit of the preheat pulse is classified according to the amount of ejection depending on the characteristics of each recording head, and this rank is stored in the ROM 128 as table pointer information.

In the ranking by the discharge amount, the range of one rank is equal to the change ± ΔV of one table of the preheat pulse width P ₁ shown in FIGS.

[0086] In the table pointer setting for the pre-heat pulse P ₁ described above, the discharge a large amount of recording head, the environmental temperature (head temperature) standard temperature, e.g., 5.0 preheat pulse width P ₁ of the upper limit value when the ℃ Is shorter than the upper limit value of the standard driving conditions (for example, P ₁ = 1.87 μsec) to reduce the ejection amount, and the standard ejection amount V _DO = 30.
0 [ng / dot].

On the other hand, in a recording head having a small discharge amount, the value of the preheat pulse width P ₁ when the environmental temperature is the standard temperature is set longer than the standard driving condition to increase the discharge amount, and the standard discharge amount V _DO = 30. 0.0 [ng / dot].

As described above, P of the preheat pulse P ₁
The table pointer for performing WM control is set to the RO of the head.
By reading as M information, it is possible to change the setting conditions (driving conditions) on the main body side, it is possible to absorb variations in the discharge amount of each head, and easily stabilize the image quality even in the main body using the replaceable recording head. Not only is it possible to improve the yield of the head, but also to reduce the cost of the cartridge head.

As described above with reference to FIGS. 1 to 11, by modulating the first pulse of the divided pulses as the driving signal for the heating element, the ejection amount can be stabilized, while the recording head It is also possible to control the temperature efficiently. Then, the control width of the print head temperature can be made relatively wide from T ₀ to T _L , for example, as shown in FIG.

The relationship between the ink ejection speed and the ink temperature is generally as shown in FIG. That is, as the temperature increases, the ejection speed increases, and up to a certain temperature, the ejection speed linearly increases with an increase in the ink temperature. Such a relationship between the ink temperature and the ejection speed can be explained as follows.

That is, the discharge speed is set to V _INK and the discharge amount is set to M
_INK, when the volume of the bubbles generated in the ink by heat heating elements is generated and V _B, the following equation holds.

[0092]

V _INK = k (INV _B / ∂t) / M _INK where k is a proportional constant and ∂ / ∂t is a partial derivative with respect to time.

As understood from the above equation, the discharge speed is
It is proportional to the bubble expansion speed and inversely proportional to the discharge rate. Therefore,
For example, if the discharge amount is reduced and / or the expansion speed of the bubble is increased, the discharge speed increases. here,
Reducing (changing) the discharge amount is shown in FIGS.
As described with reference to FIG. 11, since the density unevenness and the like are not preferable, the control for stabilizing the ejection amount is generally performed as described above. Therefore, the ink ejection speed is often determined by the bubble expansion speed. The expansion speed of the bubble differs depending on the ink temperature (print head temperature).

FIG. 13 shows the bubble generation time t and the volume V of the bubble.
FIG. 3 is a diagram showing a relationship with _B.

In the figure, curves a and b are single pulses in which the drive signal is not divided and the recording head temperature is 2
5C and 40C are shown. As can be seen, when the volume V _B of the bubble increases (when inflated), the slope of the curve, i.e. the expansion rate is larger curve b when the recording head temperature is relatively high.

From the above, it is possible to explain the relationship shown in FIG. 12 that the higher the temperature of the recording head, that is, the higher the temperature of the ink filling the ink path and the common liquid chamber, the higher the ejection speed.

However, when the temperature of the recording head is increased as described above, the ejection speed can be increased.
As shown in FIG. 13, towards the curve b when possible to increase the discharge speed, the speed of decreasing the bubble volume V _B (shrinkage rate) is small bubble defoaming time is prolonged. As a result, the refill frequency is reduced, and the above-described problem occurs.

Such a phenomenon is better in the case of the curve b.
This can be explained by the fact that the temperature of the ink around the bubbles is high and the time for defoaming is prolonged.

Therefore, in the present invention, the temperature of the recording head,
In other words, while keeping the ink temperature around the bubble low when the bubble is in the process of contracting, the temperature of the ink required for ejection is increased to increase the ejection speed.

FIG. 14 is a diagram showing the relationship between the pulse for driving the heating element and the temporal change of the bubble volume.

In FIG. 14, when a single pulse A is applied to the heat generating element, the temperature of the heat generating element and the volume of the bubble change as time elapses, as indicated by the broken line and the solid line indicated by A, respectively. That is, the driving pulse rises at time t _p, the bubble begins film boiling in t _{the as} starts expanding. Thereafter, the drive pulse falls at t ₂ , but the volume of the bubble continues to increase, and reaches a maximum at a predetermined time t _amax , and then begins to contract and disappears at a time t _af . Even when the double pulse B is applied, the bubble volume changes similarly.

Here, the defoaming time (the time from when the bubble volume is the maximum to the time when the bubble is defoamed) and the expansion time (the bubble volume from the start of the expansion to the bubble volume) when the single pulse A is applied and when the double pulse B is applied Comparing (up to the maximum), when the defoaming time is almost equal, the expansion time is shorter when the double pulse B is applied. That is, the expansion speed increases. This can be shown by comparing curves a and c in FIG.

Therefore, even if the same defoaming time is used,
The discharge speed can be made higher when a double pulse is applied. This is because the temperature of ink required for ejection is increased by the first pulse of the double pulse, whereby the ejection speed can be increased. Therefore, the ejection speed can be controlled by modulating the width P1 of the _first pulse.

When the heating element is driven by this double pulse, as described with reference to FIGS. 1 to 11, the temperature of the recording head can be controlled relatively easily. At the same time as the foaming time can be shortened, the discharge amount can be stabilized.

Now, with respect to the above-mentioned double pulse (divided pulse), a preferred method of setting the pulse width for the driving conditions of the recording head and the conditions for forming an image on a recording medium will be described.

1) Considering the signals P ₁ , P ₂ , and P ₃ , the conventional double pulse merely considers the input of the signals P ₁ and P ₃ , so that the given pause interval is kept constant. It is assumed that However, when changing the pre-heating amount (P _1), when the pause time P ₂ constant, pre-heating amount (P ₁₎ is the actual foaming during pulse P ₃
Has become an unstable element that easily affects the

[0107] In the present invention, as a result of consideration of this point, with respect to application time P ₁ before heating pulses, the pause interval P
₂ satisfies P ₁ ≦ P ₂ , whereby the stepwise gradation region by the applied pulse P ₁ can be expanded, and the desired condition can be efficiently achieved. In addition, time P ₂ is equal to pulse P ₃
By satisfying P ₂ <P ₃ with respect to the application time P ₃ , it is possible to efficiently form desired ink droplets within a given driving cycle of the apparatus. If P ₂ ≧ P ₃ , the balance between pre-heating (P ₁ ) and bubble formation (P ₃ ) is relatively difficult to stabilize, and the dispersion of ink droplets becomes large.

Therefore, in the substantial device, P ₁ ≦ P ₂
<Thus it is most preferable to satisfy the P _3. It is well known to those skilled in the art in recent devices that the layer thickness and resistance value of the heating resistor are within a certain limited range when bubbles are formed using thermal energy in this double pulse. 15 (V) to 30
(V) is set. The above condition P ₁ ≦ P ₂ <P ₃
Is particularly effective in the range of this voltage value, and has an extremely excellent effect in a high frequency range of 5 KHz or more, preferably 8 KHz or more, and ideally 10 KHz or more.

Also, considering the value of P ₃ , from the stabilization of bubble formation, by satisfying ₁ μsec ≦ P ₃ ≦ 5 μsec, the above condition P ₁ ≦ P ₂ <P ₃ has an extremely effective effect. Can be

2) The prescribed size of the ejection amount according to the recording medium will be described below.

It can be said that the ink ejection amount V _{d (pl / dpt)} is determined by the pixel density and the ink bleeding rate of the recording medium (considering the area factor). For example,
To enable solid recording at a pixel density of 400 dpi,
An ink ejection amount of about 8 nl / mm ² is required for the recording medium. For this reason, in order to secure this ejection amount once or several times, the ejection amount Vd is 5 to 50 _{(pl / dot)} .

Therefore, as a more specific device setting,
The P ₁ ≦ P ₂ <so as to obtain the discharge amount Vd while satisfying P _3, by changing the P _1, the driving condition suitable for the recording medium and the recording method can be easily set.

3) The maximum range of the driving frequency will be described.

The drive frequency f (KHz) is determined by the recording speed, refill characteristics, and the like. When the ejection amount is set under the above condition 1), the drive frequency is determined accordingly. That is, if the ejection amount is small, the driving frequency increases,
The more it is, the lower it is. As a result, considering the range where Vd is 5 to 50, the driving frequency f is 2 KHz to 20 K
Hz range.

4) The number of ejections of the recording head is n _N, and the drive system for ejecting from the n _N ejection openings is block driving (the ejection is sequentially performed for each block; the number of blocks: n _B). , Number of segments (number of outlets / block):
N _seg ).

Here, the pulse width P _d of the above double pulse
Is defined as P _d = P ₁ + P ₂ + P ₃ , the maximum of P _d can theoretically be T / n _B (T: drive cycle). However, if P _d = T / n _B , electrical crosstalk may occur during the driving of each block, causing unnecessary foaming in the ink. Alternatively, the switching time of the transistor for switching the drive block is required. Therefore, a pause time of the pulse is required between the driving of each block. If this time is α, the time _Pn required for one double pulse is _Pd + α.

Therefore, under the above conditions 1) to 5), P _n
Maximum _{(P n) max} is _{(P n) max = T /} N B
= 1 is / _(n B f), _{also, P d <1 / (n} B
f). For example, since 2 ≦ f ≦ 20 from the condition 3), when the driving frequency is within this range, P _d <1 /
(2n _B ). Here, when one block of eight discharge ports, the number n _N are 64 each discharge port 1
If there are 28 and 256, n _B is 8, 1 respectively.
6, 32. When the division drive is not performed, n _B = 1 regardless of the number of discharge ports. Therefore, for example, when n _B = 8, P _d
<1 / (2 × 8) _msec , that is, 6.25 μsec
c <P _d <62.5 μsec.

[0118] _{Similarly, P d <1 / (5n} B) when each 5 ≦ f (≦ 20), when 8 ≦ f of (≦ 20), P _d
<1 / (8n _B ), P _d <1 when 10 ≦ f (≦ 20)
/ Become (10n _B).

As described above, P _d = P ₁ + P ₂ +
P ₁ , P ₂ , P ₃ satisfying the relationship of P ₃ <1 / (n _B f)
Has the following relationship.

1) No matter how small P ₁ is, P ₃ must be large enough to foam. 2) The maximum value of P _1, it does not only foam pulse P _1. 3) resting pulse width P ₂ is preferably longer as long as it can be in the condition not exceeding the range of (P _{n) max.}

Next, an ink jet recording apparatus in which the ejection speed control described in the above embodiment is performed by changing the distance between the recording head and the recording medium (hereinafter, also referred to as the sheet distance) according to the material of the recording medium. An example in which the present invention is applied will be described.

For example, when coated paper is used, the distance between the papers can be made relatively short, and when the ink absorption is poor, such as plain paper or OHP paper, the recording head and the recording medium are separated by cockling or beading. In this case, the distance between the sheets is increased because the contact between the sheets is likely to occur. In such a case,
In the case of coated paper, the distance between papers = 0.7 mm, discharge speed = 1
2 m / s, and in the case of plain paper etc., the paper distance = 1.2 m
m, discharge speed = 16 m / s.

The control of the discharge speed is performed as shown in FIGS.
This can be performed by setting the temperature of the print head by controlling the print head temperature described in 1 and further modulating the first pulse of the double pulse.

As described above, when the inter-paper distance is large, by increasing the ejection speed, it is possible to prevent the displacement of the landing position of the ejected ink droplet from occurring, and to prevent the landing accuracy from being lowered.

Next, an example of the configuration when the present invention is applied to a monochrome printer will be described.

This printer employs a detachable recording head which is detachably mounted. Therefore, it is desirable to set an optimum refill frequency for the printhead according to the use conditions of the printer to which the printhead is mounted. For example, in the case of a monochrome printer having a relatively low driving frequency (slow recording speed), the refill frequency may be relatively low. Therefore, the ejection speed can be controlled by pulse width modulation of the double pulse without lowering the print head temperature.

In the above embodiment, the ink temperature is controlled by performing the preheat pulse control of the double pulse, thereby controlling the discharge speed.
The control of the ejection speed is not limited to the above example, and may be performed by, for example, irradiating the ink with laser light.
In this case, it is possible to control the ejection speed by changing the temperature, viscosity, and surface energy of the ink by making a part of the top plate or the like of the recording head transparent and irradiating the ink with laser light through this part. it can.

(Others) It should be noted that the present invention includes a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for performing ink ejection, particularly in an ink jet recording system. An excellent effect is obtained in a recording head and a recording apparatus of a type in which the state of ink is changed by the thermal energy. This is because according to such a method, it is possible to achieve higher density and higher definition of recording.

The typical configuration and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,740.
It is preferable to use the basic principle disclosed in the specification of Japanese Patent No. 796. This method is a so-called on-demand type,
Although it can be applied to any type of continuous type, in particular, in the case of the on-demand type, it can be applied to a sheet holding liquid (ink) or an 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 the nucleate boiling, heat energy is generated in the electrothermal transducer, and film boiling occurs on the heat acting surface of the recording head. Liquid (ink) corresponding to this drive signal on a one-to-one basis.
This is effective because air bubbles inside can be formed. The liquid (ink) is ejected through the ejection opening by the growth and contraction of the bubble to form at least one droplet. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of a liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further, if the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

As the configuration of the recording head, in addition to the combination configuration (a linear liquid flow path or a right-angle liquid flow path) of the combination of the discharge port, the liquid path, and the electrothermal converter as disclosed in the above-mentioned respective specifications, U.S. Pat. No. 4,558,333 and U.S. Pat.
A configuration using the specification of Japanese Patent No. 59600 is also included in the present invention. In addition, Japanese Unexamined Patent Application Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal transducer for a plurality of electrothermal transducers, and an aperture for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration is based on JP-A-59-138461, which discloses a configuration corresponding to a discharge unit. That is, according to the present invention, recording can be reliably 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 on which a recording apparatus can record. 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 integrally formed recording head.

In addition, even in the case of the serial type as described above, a recording head fixed to the apparatus main body or an electric connection with the apparatus main body or ink from the apparatus main body by being mounted on the apparatus main body. 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 provided integrally with the recording head itself is used.

Further, it is preferable to add a recording head discharge recovery unit, a preliminary auxiliary unit, and the like as the configuration of the recording apparatus of the present invention since the effects of the present invention can be further stabilized. If these are specifically mentioned, the recording head is heated using capping means, cleaning means, pressurizing or suction means, an electrothermal transducer, another heating element or a combination thereof. Pre-heating means for performing the pre-heating and pre-discharging means for performing the discharging other than the recording can be used.

The type and number of recording heads to be mounted are not limited to those provided only for one color ink, for example, and for a plurality of inks having different recording colors and densities. A plurality may be provided. That is, for example, the printing mode of the printing apparatus is not limited to a printing mode of only a mainstream color such as black, but may be any of integrally forming a printing head or a combination of a plurality of printing heads. The present invention is also very effective for an apparatus provided with at least one of the recording modes of full color by color mixture.

In addition, in the embodiments of the present invention described above, the ink is described as a liquid. However, an ink which solidifies at room temperature or lower and which softens or liquefies at room temperature may be used. In general, the ink jet method generally controls the temperature of the ink itself within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range. Sometimes, the ink may be in a liquid state. In addition, in order to positively prevent temperature rise due to thermal energy by using it as energy for changing the state of the ink from a solid state to a liquid state, or to prevent evaporation of the ink, the ink is solidified in a standing state and heated. May be used. In any case, the application of heat energy causes the ink to be liquefied by the application of the heat energy according to the recording signal and the liquid ink to be ejected, or to start solidifying when it reaches the recording medium. The present invention is also applicable to a case where an ink having a property of liquefying for the first time is used. In such a case, the ink
JP-A-54-56847 or JP-A-60-7
As described in Japanese Patent Publication No. 1260, it is also possible to adopt a form in which the sheet is opposed to the electrothermal converter in a state where it is held as a liquid or solid substance in the concave portion or 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.

Further, the form of the ink jet recording apparatus of the present invention is not limited to those used as image output terminals of information processing equipment such as computers, copying apparatuses combined with readers and the like, and facsimile apparatuses having a transmission / reception function. It may take a form.

[0137]

As is apparent from the above description, according to the present invention, the expansion speed of the bubbles generated in the ink is controlled by modulating the waveform of the preceding signal among the driving signals composed of a plurality of signals. This makes it possible to control the ink discharge speed. Further, the temperature of the ink ejected by the modulation of the preceding signal can be locally controlled, whereby the temperature of the ink around the bubble when the bubble contracts can be controlled by controlling the ejection speed and the ejection amount. Can be set low regardless of As a result, the contraction speed can be increased, and the refill frequency can be increased.

As a result, even if the temperature of the recording head changes due to the environmental temperature or self-heating, the ejection speed and the refill frequency can be controlled well, and a high-quality image can be recorded.

[Brief description of the drawings]

FIG. 1 is a diagram showing a pulse waveform of a pulse width modulation driving method of a divided pulse according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining a discharge amount control method according to one embodiment of the present invention.

FIGS. 3A and 3B are a cross-sectional view and a front view, respectively, of a recording head used in Examples.

FIG. 4 is a diagram showing a relationship between a discharge amount and a pulse width according to the present invention.

FIG. 5 is a diagram showing a relationship between a discharge amount and a head temperature according to the present invention.

FIG. 6 is a waveform diagram of pulses set in a table according to an embodiment of the present invention.

FIG. 7 is an explanatory diagram showing a head temperature and a preheat pulse modulation control table corresponding to the head temperature according to the embodiment of the present invention.

FIG. 8 is a flowchart of a pulse width modulation sequence according to one embodiment of the present invention.

FIG. 9 is a schematic top view of a heater board used in one embodiment of the present invention.

FIG. 10 is a perspective view of a full-color printer according to one embodiment of the present invention.

FIG. 11 is a block diagram illustrating a control configuration of the printer.

FIG. 12 is a diagram showing a relationship between ink temperature and ejection speed.

FIG. 13 is a diagram illustrating a generation process of bubbles generated in the ink.

FIG. 14 is a diagram showing a change in a heating element temperature and a bubble volume with respect to a driving pulse applied to the heating element.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electrothermal transducer (discharge heater) 2 carriage 3 ink liquid path 7 discharge port 9 heater board (Si substrate) 11 aluminum plate 20A, 20B temperature sensor 30A, 30B temperature control heater 801 CPU 803 ROM 805 RAM

Claims (12)

(57) [Claims] 1. A discharge control method for an ink jet recording head that generates bubbles in ink by thermal energy generated by a heating element by application of a drive signal, and discharges ink along with the generation of the bubbles. , Heat energy without discharging ink
A pulse P ₁ to generate , a pulse pause interval P ₂ , and
A plurality of pulse including a pulse P ₃ for ejecting fine ink
Consists scan is generated to _{P 1,} P 2, _{P 3} in the order
And the signal, corresponding to the pulse P ₃ to the ink jet recording head
A pulse of a predetermined width determined in
According to the temperature of the jet recording head, the temperature is set to a predetermined value.
When in the temperature range, by modulating the width of pulses P ₁ to relatively preceding one of the plurality of pulses, said Lee
Control the discharge of the ink and modulate the pulses
P ₁ width and the pulse relationship is _P 1 and the width of _{P 2 <P 2}
Ejection control method for an ink jet recording head, characterized in that it. Wherein the width of the pulse _{P 2,} the pulse _{P 1}
And the pulse P ₂
The relationship between the width of the pulse P ₃ is, P when the width is smallest
_{2 <-in} according to claim 1, characterized in that the P ₃
An ejection control method for a jet recording head. 3. The temperature of said ink jet recording head is
When in the temperature range exceeding the predetermined temperature range, the
Claim, characterized in that the width of the pulse P ₁ is zero 1
Or the ejection control of the inkjet recording head according to item 2.
Method. 4. An ink jet having a plurality of heating elements.
Using a recording head, the heating element by the application of drive signals ink by generating bubbles by heat energy is generated, a discharge control method for an ink jet recording head for ejecting ink is accompanied to the generation of bubble, the The drive signal is used to generate thermal energy without discharging ink.
A pulse P ₁ to generate , a pulse pause interval P ₂ , and
A plurality of pulse including a pulse P ₃ for ejecting fine ink
And P ₁ , P ₂ , and P ₃ are generated in that order.
And the signal, corresponding to the pulse P ₃ to the ink jet recording head
And a pulse having a predetermined width
The width of P ₁ and the width of the pulse _{P 2} as _P 1 _{<P 2,}
The temperature of the inkjet recording head is within a predetermined temperature range;
On one occasion, ejection of ink by modulating the width of pulses P ₁ to relatively preceding one of the plurality of pulses in response to the temperature
Controlling the output, dividing the plurality of heating elements into a plurality of blocks,
When the drive signal is applied for each block to drive sequentially,
The number of locks and n _B, the drive signal to the heating element
When applied to the drive frequency for driving is in the range of f kHz to 20 KHz, the plurality of pulses _{P 1,} P 2, _{P 3} its
An ejection control method for an ink jet recording head, wherein the sum of the respective widths (P ₁ + P ₂ + P ₃ ) is P ₁ + P ₂ + P ₃ <1 / ( f × n _B ). 5. The driving frequency f (KHz) is 2, 5,
5. The method according to claim 4, wherein
The discharge control method for an ink jet recording head according to the above. 6. The amount of the ejected ink is 5 to 50 (p
1 / ink drop), and the voltage of the pulse is 15-30.
(V), the pulse width of the pulse _{P 3} is 1 _<P 3 _<5 (μ
The method according to claim 4, wherein the method is ( sec) . 7. A heating element is generated by applying a drive signal.
The generated thermal energy generates bubbles in the ink,
Ink jet recording that ejects ink as bubbles are generated
In an ink jet recording apparatus for performing recording by ejecting ink from the recording head using a recording head , the drive signal is used to generate thermal energy without ejecting ink.
A pulse P ₁ to generate , a pulse pause interval P ₂ , and
A plurality of pulse including a pulse P ₃ for ejecting fine ink
Consists scan is generated to _{P 1,} P 2, _{P 3} in the order
And signal, the ink jet recording f the pulse P ₃
A pulse of a predetermined width determined according to the
According to the temperature of the ink jet recording head, the temperature
When the degree is in a predetermined temperature range, by modulating the width of pulses P ₁ to relatively preceding one of the plurality of pulses, to control the discharge of the ink is modulated
The width of the pulse P _1, the relationship between the width of the pulse P ₂
P 1 _<ink jet recording apparatus characterized in that comprises driving means for pulse and a P _2, a. Wherein said driving means, the width of the pulse P ₂
And when modulated according to the modulation of the width of the pulse P ₁ together
The pulse P ₃ when the width of the pulse P ₂ is the minimum.
Characterized in that the relation with the width of P is P ₂ <P ₃
The inkjet recording apparatus according to claim 7 . 9. The ink jet recording apparatus according to claim 1 , wherein
Temperature range in which the recording head temperature exceeds the predetermined temperature range
When in, especially to the width of the pulse P ₁ to zero
Inkjet recording <br/> apparatus according to claim 7 or 8, symptom. 10. An ink jet device having a plurality of heating elements.
A preparative recording head, ink bubbles are generated by the thermal energy the calling <br/> thermal element is produced by application of the drive signals, using an ink jet recording head for discharging ink is accompanied to the generation of bubble To record
In a jet recording apparatus, the drive signal is converted into thermal energy without discharging ink.
A pulse P ₁ to generate , a pulse pause interval P ₂ , and
A plurality of pulse including a pulse P ₃ for ejecting fine ink
And P ₁ , P ₂ , and P ₃ are generated in that order.
And signal, the ink jet recording f the pulse P ₃
A pulse of a predetermined width determined according to the
The pulse width and the _P 1 in the width and the pulse _{P 2} of _{P 1} <P
₂ , the temperature of the ink jet recording head is a predetermined
When in the temperature range, by modulating the width of pulses P ₁ to relatively preceding one of the plurality of pulses in response to the temperature
Driving means for controlling ink ejection , dividing the plurality of heating elements into a plurality of blocks,
When the drive signal is applied for each block to drive sequentially,
The number of locks and n _B, the drive signal to the heating element
When applied to the drive frequency for driving is in the range of f kHz to 20 KHz, the plurality of pulses _{P 1,} P 2, _{P 3} its
An ink jet recording apparatus, wherein the total width of respectively _{(P 1 + P 2 + P} 3) is an _{P 1 + P 2 + P 3} <1 / (f × n B). 11. The driving frequency f (KHz) is 2,
Claims, characterized in that at 5, 8, 10, whichever is
An ink jet recording apparatus according to claim 10 . 12. The amount of ink to be ejected is 5 to 50.
(Pl / ink drop), and the voltage of the pulse is 15-30.
(V), the pulse width of the pulse _{P 3} is 1 _<P 3 _<5 (μ
The ink jet recording apparatus according to claim 10, wherein sec) .