JP2001096732A - Ink-jet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording device and a recording method, capable of preventing various damages by heat caused by temperature rise of a recording head. SOLUTION: This device comprises electro-thermal converters 26a-26i provided in a plurality of nozzles of recording heads, a recording mode setting means with a plurality of recording modes having quantities of heat per unit time to be generated in the electro-thermal converters different with each other set therein, a temperature detecting means 108 for detecting the temperature of the recording heads, and a power supply number calculating means 101 for calculating the number of power supplies of the electro-thermal converters necessary for a recording operation in a predetermined recording region, wherein a mode selecting means 101 for selecting a recording mode, capable of restraining the temperature of the recording heads to lower than a predetermined temperature according to the temperature of the recording heads 11a-11f and the number of power supplies of the electro-thermal converters, is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus, and more particularly, to an ink jet recording apparatus in which a liquid is foamed by heat and ink is ejected by energy generated at the time of foaming.

[0002]

2. Description of the Related Art By supplying power to electrothermal transducers arranged corresponding to a plurality of nozzles of a recording head, a recording liquid on the electrothermal transducer is heated and foamed, and the foaming energy is used. In a so-called bubble jet type ink jet recording apparatus that discharges the recording liquid, heat generated by the electrothermal converter may be accumulated in the recording head,
The heat sometimes caused excessive bubbling of the ink liquid.

[0003] In this case, an ink liquid chamber in the recording head,
In addition, a phenomenon that bubbles remain in the nozzle portion occurs, which causes inconveniences such as non-ejection of ink droplets and deviation of landing positions on a recording medium in a recording operation.

For this reason, measures have been taken to increase the heat radiation by using a metal having excellent thermal conductivity in the plate portion constituting the recording head. However, in recent years, heat has been increased due to an increase in driving frequency and an increase in the number of nozzles. There is a tendency that the amount of heat generation tends to increase further, and a situation may occur in which it is not possible to completely suppress the amount of heat storage only by taking the above measures. As a countermeasure against such a situation, conventionally, a detecting means for detecting the temperature of the recording head is provided, and when the head temperature has reached a predetermined temperature or higher, the recording operation is performed until the temperature of the recording head falls below the predetermined temperature. There is also proposed a recording device for performing such a process as stopping recording. Hereinafter, this technique is referred to as Conventional Technique 1.

In the case where an adverse effect occurs due to the amount of heat stored, for example, a detecting means for detecting the temperature of the recording head and a head based on the energy supplied to the recording head are disclosed in Japanese Patent Application Laid-Open No. Hei 6-336024. It has an estimating means for estimating the temperature, compares the head temperature at the time of inputting the energy and the estimated temperature, and when the estimated temperature and the actually measured temperature are significantly different, judges that an apparatus error has occurred, and performs a recovery process. Also, those that execute processing such as error processing and error processing are known. Hereinafter, this technique is referred to as Conventional Technique 2.

[0006]

However, in the above-mentioned prior art 1, after a temperature abnormality occurs in the recording head,
In some cases, it was not possible to sufficiently avoid heat damage because measures were taken. For example, in a recording apparatus of a line recording system for recording one image divided into a plurality of lines,
Even if an abnormal temperature rise is detected during the recording of one line, the recording operation is continued in the abnormal temperature state until the recording operation of that line is completed, and the recording operation of the next line is started for the first time. A measure is taken to suspend the recording operation based on the detection of the abnormal temperature and to wait until the temperature of the recording head decreases. For this reason, there is a possibility that the recording head may be damaged by the abnormal temperature rise during recording in the abnormal temperature state.

Further, in the above-mentioned prior art 2, when an abnormal temperature rise occurs in the recording head, this is detected, but the occurrence itself of the abnormal temperature rise is suppressed. It was not yet sufficient for protection.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to provide a recording apparatus and a recording apparatus capable of preventing the occurrence of various types of heat damage caused by a rise in the temperature of a recording head. I do.

[0009]

In order to solve the above problems, the present invention has the following configuration.

That is, the present invention has a plurality of nozzles formed in a recording head, and an electrothermal converter disposed in each nozzle, and a recording liquid is supplied by electric energy supplied to the electrothermal converter. In the ink jet recording apparatus, the recording liquid is ejected from the nozzles by the energy generated at the time of the thermal foaming, and the recording operation is performed by relatively moving the recording head and the recording medium. Recording mode setting means for setting a plurality of recording modes having different heat amounts per unit time to be generated by the heat transducer, temperature detecting means for detecting the temperature of the recording head, and recording operation in a predetermined recording area Means for calculating the number of times of energization of the electrothermal transducer required for the operation of the electrothermal transducer. Depending on the number of times, and is characterized in that the temperature of the recording head and a mode selector for selecting a recording mode which can suppress below the predetermined temperature.

The mode selection means may set the recording mode according to the temperature of the recording head, the number of times of energization of the electrothermal transducer, and the heat radiation environment of the recording head.

[0012] Further, as the plurality of recording modes to be set, different ink ejection frequencies are used, or a recording mode with a low ink ejection frequency is selected for an image in which the number of times of power supply to the electrothermal transducer is large. For an image in which the number of times of energization of the electrothermal transducer is small, a recording mode having a high ink ejection frequency may be selected.

The recording head reciprocates relative to the recording medium in the main scanning direction and moves in a sub-scanning direction that intersects the main scanning direction, so that the recording operation on the recording medium is performed. The number of times of energization may be calculated, and the number of times of energization may be calculated for each main scan based on image data.

Further, the recording head performs a recording operation only at the time of forward movement in the main scanning direction, the number-of-energizations calculating means calculates the number of energizations at the time of forward movement, and the mode setting means responds to each calculation result. It is also possible to set a print mode having a different ejection frequency.

Further, the recording head performs a recording operation at the time of forward movement and backward movement in the main recording scanning direction, and the power supply number calculating means calculates the number of power supply to be performed at the time of forward movement and backward movement. The mode setting means may set a printing mode having an ejection frequency according to each calculation result, and further, the printing head performs a printing operation only at the time of forward movement in the main printing scanning direction. The number-of-times calculating means may calculate the number of times of energization at the time of forward movement, and the mode setting means may set the operation speed at the time of backward movement according to each calculation result.

According to the present invention having the above-described structure, the number of energizations performed to the print head during the printing operation is detected, and the current temperature of the print head is detected. Control the recording mode.
The print mode includes, for example, a discharge frequency of the print head as a setting element.If the number of times of power supply to the print head is large, a print mode with a low discharge frequency is selected, and the print operation is performed slowly to perform printing. Abnormal temperature rise in the head can be prevented. If the number of times of energization is small and the possibility of occurrence of abnormal temperature rise, which is not so high, of the current print head is low, a print mode with a high ejection frequency is selected to perform a print operation at high speed.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In this embodiment, a color recording head capable of ejecting ink of six colors of black, cyan, light cyan, magenta, light magenta, and yellow is used, and the line is moved by moving the recording head along the main scanning direction. An example in which the present invention is applied to an ink jet recording apparatus that performs recording will be described.

FIG. 1 is a perspective view schematically showing an ink jet recording apparatus to which the present invention is applied. In the ink jet recording apparatus shown here, the drive of a paper feed motor (LF motor) 6 composed of a stepping motor is transmitted to a pair of upper and lower paper feed rollers 3 via gears and the like, and is supplied between the paper feed rollers 3. The recording paper 4 is sent out in the sub-scanning direction (the direction indicated by arrow B in the figure). The paper fed by the paper feed roller 3 is supported at its lower part by a platen plate 7 and is introduced between a pair of upper and lower paper pressing rollers 8 while maintaining flatness. The paper is fed forward while being held in a planar manner by the paper holding roller 3 and the paper pressing roller 8.

In accordance with the sheet transport operation, the carriage 13 reciprocates with the head units 2a and 2b to perform a recording operation on the sheet. That is, the head carriage 13 is driven by a carriage motor (CR motor) 12 controlled by a control system circuit to be described later, along the guide shaft 5 provided in parallel with the platen plate 7 in the main scanning direction (in FIG. (Direction shown by arrow A).

In the head unit 2a, recording heads 11a, 11b, 11c are provided with a head carriage 13.
The ink tanks 1a, 1b, 1c filled with black, magenta, and cyan inks are fixed so as to be detachable while being fixed at fixed intervals in the moving direction (direction indicated by arrow A) of the head unit 2b. Has a recording head 11
d, 11e, and 11f are fixed at fixed intervals with respect to the moving direction (main scanning direction) A of the head carriage 13, and the ink tanks 1d, 1e, and 1f filled with light magenta, light cyan, and yellow ink are attached and detached. It is kept possible.

FIG. 2 is a perspective view schematically showing the recording head. Since the recording heads 11a to 11f have substantially the same configuration, the recording head 11a that discharges black ink will be described here as an example. FIG.
As shown in FIG.
6i and an electrode for supplying power thereto (not shown)
Further, on the substrate 25, there are formed nozzles 24a to 24i for independently accommodating the respective electrothermal transducers 26a to 26i and the respective electrodes, and a common liquid chamber 23 communicating with the nozzles. At the end of each nozzle, ink discharge ports 27a to 27i are formed.

In the common liquid chamber 23 of the recording head 11a, black ink is supplied from the above-described ink tank 1a as shown in FIG.
It is supplied from the direction of the arrow C in the middle, and is supplied to the common liquid chamber 23 after impurities such as dust are removed by the filter 22. The black ink supplied to the common liquid chamber 23 is sucked and supplied into the nozzles 24a to 24i by capillary action, and forms and holds a meniscus near the ink discharge ports 27a to 27i.

In this meniscus forming state, when electricity is supplied to the electrothermal converters 26a to 26i, the electrothermal converter 26a
The ink is heated on a to 26i to foam, and the foaming energy causes the ink droplets to be discharged from the ink discharge ports 27a to 27i in the direction of arrow D in FIG. And
When ink is ejected from the ink ejection ports 27a to 27i, ink is supplied from the common liquid chamber 23 into the nozzles 24a to 24i again by the action of the capillary phenomenon, and an image is formed on the entire recording paper by repeating the above operation. Is done.

Incidentally, the electrothermal transducers 26a to 26i
When the recording heads 11a to 11
An increase in the amount of current flowing through the wiring portion f causes a large voltage drop, and the voltage required for ink discharge may not be obtained. For this reason, the electrothermal transducer is usually divided into a plurality of groups, and the drive timing of each group is shifted. Here, the electrothermal converters 26a, 26d, and 26g are group A, the electrothermal converters 26b, 26e, and 26h are group B, and the electrothermal converters 26c, 26f, and 26i are group C, and the timing of each group is small. Is turned on.

FIG. 3A shows the waveform of the energizing pulse P to the electrothermal transducers 26a to 26i in this embodiment, and FIG. 3B shows one pulse shown in FIG. It is a figure which expands and shows P. One energizing pulse P shown in FIG. 3A is a pulse for generating the amount of heat necessary to cause one bubbling of the ink, and the energizing time is determined so that the bubbling of the ink is stabilized. I have. In the ink jet recording apparatus of the present embodiment, the energization is performed twice by the double pulses P1 and P2 as shown in the figure, and the group A, the group B, and the group C , The energizing pulses P slightly shifted in timing are supplied.

In each group, the interval between adjacent pulses (t in the figure) determines the interval between ink ejections (ejection frequency (f)).
From the moment when the ink is discharged from the nozzles 24a to 24i and the ink in the nozzles 24a to 24i is exhausted, the time required until the ink is replenished into the nozzles 24a to 24i again by the capillary phenomenon and the meniscus is normally held is minimized. Determined as time. Actually, the pulse interval t is determined in consideration of, for example, further stabilizing the ejection state with respect to the minimum required time until the meniscus is formed.

It should be noted that not only the black ink recording head 11a described above but also other recording heads 11b, 11d, 11e and 11f to which inks such as magenta, cyan, light magenta, light cyan, and yellow are supplied. ,
The ink is heated and foamed by applying the above-described energizing pulse P to the electrothermal transducers 26a to 26i disposed in the nozzles 24a to 24i, and the ejection ports 27a of the nozzles 24a to 24i are formed by the foaming energy of the ink. To 27i to eject ink droplets.

FIG. 4 is a block diagram showing a configuration of a control system circuit according to this embodiment. In this embodiment, reference numeral 100 denotes a main control unit. The main control unit 100 includes a CPU 101 that executes processing operations such as calculation, control, determination, setting, and control, and a control program and the like to be executed by the CPU 101. ROM 102 for storing;
A RAM 103 used as a print data buffer, a work area for processing by the CPU 101, and an input / output port 104 are provided.

The input / output port 104 is connected to the above-described paper transport motor (LF motor) 6, carriage motor (CR motor) 12, and recording heads 11a to 11f.
Drive circuits 105, 106 and 107 are connected, a head temperature sensor (head temperature detecting means) 108 for detecting the temperature of the recording heads 11a to 11f, and a home for detecting the home positions of the recording heads 11a to 11f. Sensors such as the position sensor 109 are connected. Further, the main controller 100 is connected to a host computer (not shown) via an interface circuit 110.

In the ink jet recording apparatus having the above configuration, when recording, first, the CR motor 12 is driven via the drive circuit 106 while the recording paper 4 is stopped.
Is driven to move the head carriage 13 in the forward main scanning direction (hereinafter, simply referred to as the forward direction) A1, and the electrothermal transducers 2 at necessary locations based on the print data are moved.
6a to 26i, the recording head 1
1f, yellow ink from the recording head 11e, light magenta ink from the recording head 11d, cyan ink from the recording head 11c, magenta ink from the recording head 11b, and black ink from the recording head 11a. The color printing for one line is performed by overprinting.

At this time, the moving speed of the head carriage 13 is determined in accordance with the ejection frequency (f) determined by the driving conditions of the recording heads 11a to 11f. That is, if the ejection frequency (f) is low, the moving speed of the head carriage 13 is set to a correspondingly low speed,
If the ejection frequency (f) is high, the moving speed of the head carriage 13 is set to be correspondingly high, so that the number of ink dots landed per unit area of the paper is the same even if the ink ejection frequency is different. Is controlled.

When the recording operation of one line is completed in this way, the LF motor 6 is driven via the drive circuit 105, and the recording paper 4 is fed out by a fixed amount in the direction of arrow B. The head carriage 13 moves in the backward main scanning direction (hereinafter, simply referred to as the backward direction) A2 while the recording paper 4 is being fed stepwise. During this time, since the electrothermal transducers 26a to 26i of the recording heads 11a to 11f are not energized, the ink ejection is temporarily stopped.

When the step feed of the recording paper 4 is completed and the recording paper 4 is stopped, and the head carriage 13 returns to a predetermined recording start position set based on the home position, the head carriage 13 moves to the arrow. The movement in the direction A is started again at a constant speed. At the same time, the ejection of ink from each of the recording heads 11a to 11f is started, and the color recording is started again. By repeating such operations a plurality of times, color printing can be performed on the entire surface of the recording paper 4. In the above-described printing operation, the recording heads 11a to 11i are provided with electrothermal transducers 26a for foaming ink. In some cases, heat is stored in the recording heads 11a to 11f due to heat generated from the heaters 26 to 26i. The amount of heat storage is determined by the amount of heat generated by one energization of each electrothermal transducer and the energization of the electrothermal transducer determined by print data. The amount of heat such as the amount of heat generated per unit time determined by the frequency and the ejection frequency (f), the amount of heat emitted by the ejected ink droplets, and the recording head 1
1a to 11f and the thermal conductivity of the members constituting the recording head 1
It is determined by the balance with the amount of heat released per unit time, which is determined by various conditions such as the ambient temperature around 1a to 11f and the wind speed (flow velocity).

Therefore, the amount of heating per unit time is suppressed,
It is possible to increase the heat radiation amount per unit time by using the recording head 11.
This is important in reducing the amount of heat stored in a to 11f and suppressing abnormal temperature rise. The ink jet printer of the present embodiment controls the amount of heat stored in the recording heads 11a to 11f by changing the ejection frequency (f) among the above parameters. That is, the electrothermal transducers 26a to 26i in one line determined by the recording data
If the number of energization times is large, the discharge frequency (f) is lowered,
By increasing the time required to record one line and reducing the amount of heat generated per unit time, the recording head 11
When the number of energizations of the electrothermal transducers 26a to 26i in one line is small by suppressing the heat storage amounts of the recording heads 11a to 11f, the recording head 11a during recording is controlled by increasing the ejection frequency and increasing the recording speed. -11i are controlled so as not to exceed a predetermined temperature.

For the purpose of simply suppressing the calorific value,
It is sufficient to set the ejection frequency (f) to a low value in advance, but in order to achieve printing at a higher distance while maintaining a stable printing state, one-line electrothermal converters 26a to 26i corresponding to the output image are required. Means is employed in which head drive modes having different ejection frequencies (f) are selectively used depending on the number of times of power supply to the head.

Hereinafter, the control operation of the ejection frequency (f) in the recording head will be described in more detail with reference to the flowchart shown in FIG. When the recording start command is input, the recording data corresponding to the first one line of the recording image data transmitted by the host PC or the like is transferred to the CPU 101 as the recording mode selecting means, and at the same time, the recording heads 11a to 11a. Head Carriage 1 with 11i
3 starts moving from the standby position to the recording start position to prepare for recording of one line (step 1).

When it is confirmed that the head carriage 13 has reached the recording start position as described above and that the transfer of one line of recording data into the CPU 101 recording mode setting unit has been completed, the recording heads 11a to 11i are next.
The temperature of the recording heads 11a to 11i is detected by the head temperature sensor 108 attached to the printer (steps 3 to 6). Further, based on the transferred recording data for one line, the CPU 101 determines the total number of times of energization to the electrothermal transducers 26a to 26i in the line from which recording is to be started (all of the electric currents applied to the recording heads 11a to 11f). The total number of times of energization of the electrothermal transducers 26a to 26i) is calculated for each of the recording heads 11a to 11f, and each recording head 11a is calculated based on the recording head temperature immediately before the start of recording and the calculated total number of energizations of the electrothermal transducer. -11i to select the optimum recording mode to be executed (step 7).

The recording mode set here is shown in FIG.
As shown in (b), the recording modes have different ejection frequencies. In this embodiment, for example, four types of recording modes A to D are set, and the ejection frequency of each mode is 10 KHz, 8 KHz, and 10 KHz, respectively. 6 kHz and 4 kHz. In this embodiment, the recording mode is selected by referring to a look-up table (recording mode setting means) shown in FIG. In the look-up table, the temperature of the print heads 11a to 11f does not rise to a predetermined temperature or higher in accordance with the print head temperature immediately before the start of printing and the total number of energizations to the electrothermal transducers 26a to 26i. The ejection frequency (f) at which the fastest printing operation can be performed is set. Then, of the print modes derived from the look-up table for each of the print heads 11a to 11f, the print mode with the lowest ejection frequency (f) is set as the print mode for one line.

When the recording mode is set in this manner, the head carriage 13 starts moving in the forward movement direction A1 at a speed corresponding to the ejection frequency (f) of the recording mode, and accordingly, the head carriage 13 first moves. The recording of one line is started in the recording mode determined in step (8) (step 8). When the recording data for one line is completed, the movement of the head carriage 13 stops (step 11). If the recording data for all lines has been recorded, the recording operation is terminated. If there is a line to be recorded, the head carriage 13 returns to the recording start position in preparation for recording the next line.
Starts moving in the return direction A2 (step 12).

Here, it is determined whether or not the print data of the line to be printed remains (step 13). If it is determined that the print data remains, the carriage 13 starts to return and the next line is started. CPU 10 records the recorded data of
1 is started (steps 14 and 15), the head carriage 13 returns to the start position, and the next 1
When the transfer of the print data for the line is completed, the process proceeds to step 3, where the head temperature is detected and the print mode is determined again, and the printing of the next line is started according to the determined print mode.

As described above, in the present embodiment, the printing is performed by setting the printing mode of the optimum ejection frequency (f) in accordance with the image data for each line, thereby performing the printing operation during the printing operation. The abnormal temperature rise of 11f can be prevented.

In the above embodiment, the recording mode is set for each line. However, the setting of the recording mode may be changed for a plurality of lines or for each recording area within one line. Further, the present invention is applicable not only to an ink jet recording apparatus that performs one-way recording that performs a recording operation only at the time of forward movement, but also to a two-way recording type ink jet recording apparatus that performs a recording operation at the time of both forward movement and backward movement. The present invention is applicable, and the present invention is not particularly limited to the above embodiment.

(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, for example, in 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 recording information and providing 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. Cause
As a result, bubbles in the liquid (ink) corresponding to this drive signal one-to-one can be formed, which is effective. 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 of the discharge port, the liquid path, and the electrothermal converter (linear liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned specifications, U.S. Pat. No. 4,558,333 and U.S. Pat. No. 44,558 which disclose a configuration in which a heat acting portion is arranged in a bending region.
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 converter for a plurality of electrothermal converters, 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 in which the length is satisfied by a combination of a plurality of recording heads, or a configuration as a single recording head integrally formed.

In addition, even in the case of the serial type as described above, the recording head fixed to the apparatus main body or the electric connection with the apparatus main body or the ink from the apparatus main body is attached to the apparatus main body by being attached to 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 ejection 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.

Regarding the type or number of print heads to be mounted, for example, only one print head is provided corresponding to a single color ink, and a plurality of inks having different print colors and densities are provided. A plurality may be provided. That is, for example, the printing mode of the printing apparatus is not limited to the printing mode of only a mainstream color such as black, but may be any of a printing head integrally configured 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 in a liquid state may be used. 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 ink from evaporating, 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 to solidify when reaching 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 is disclosed in JP-A-54-56847 or JP-A-60
As described in Japanese Patent Application Laid-Open No. 71260/1992, a configuration may be adopted in which a liquid sheet or a solid substance is held in a concave portion or a through hole of a porous sheet so as to face an electrothermal converter. 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, 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.

[0052]

As described above, according to the present invention, recording mode setting means for setting a plurality of recording modes having different heat values and temperature detecting means for detecting the temperature of the recording head are provided. Since the optimum print mode is selected according to the print head temperature immediately before the operation and the print data to be output, printing is performed, the head temperature during printing does not rise above a predetermined temperature, and the print head malfunctions. It is possible to prevent the occurrence of heat damage such as ejection failure due to the temperature rise, and to always perform stable recording.

If the heat radiation environment of the print head is taken into consideration when selecting the print mode, abnormal temperature rise of the print head can be prevented with higher accuracy.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a schematic configuration of an inkjet printer according to an embodiment of the present invention.

FIG. 2 is a perspective view schematically showing a recording head according to the embodiment of the present invention.

3A is a diagram illustrating an example of an energizing pulse according to the embodiment of the present invention, and FIG. 3B is an enlarged view of the double pulse illustrated in FIG.

FIG. 4 is a block diagram according to an embodiment of the present invention.

FIG. 5 is a flowchart showing an operation in the embodiment of the present invention.

FIG. 6 is an explanatory diagram showing a look-up table in the embodiment of the present invention.

[Explanation of symbols]

 11a to 11i Recording heads 24a to 24i Nozzles 26a to 26i Electrothermal converter 108 Head temperature sensor (temperature detecting means) 101 CPU (mode selecting means)

Claims (9)

[Claims] 1. A recording head comprising: a plurality of nozzles formed in a recording head; and an electrothermal converter disposed in each nozzle, wherein the recording liquid is heated and foamed by electric energy supplied to the electrothermal converter. An ink jet recording apparatus configured to perform a recording operation by relatively ejecting a recording liquid from the nozzle by energy generated at the time of bubbling and moving the recording head and a recording medium relative to each other; A print mode setting means for setting a plurality of print modes having different amounts of heat per unit time to be generated; a temperature detection means for detecting a temperature of the print head; and a print operation in a predetermined print area. Means for calculating the number of times of energization of the electrothermal transducer, and according to the temperature of the recording head and the number of times of energization of the electrothermal transducer. An ink jet recording apparatus characterized by comprising a mode selection means for selecting a recording mode which can reduce the temperature of the recording head below a predetermined temperature. 2. The ink jet recording apparatus according to claim 1, wherein said mode selection means sets a recording mode according to a temperature of the recording head, the number of times of energization of the electrothermal transducer, and a heat radiation environment of the recording head. apparatus. 3. The ink jet recording apparatus according to claim 1, wherein the plurality of recording modes set in the mode setting means have different ink ejection frequencies. 4. The mode selecting means selects a recording mode having a low ink ejection frequency for an image in which the number of times of power supply to the electrothermal transducer is high, and selects a recording mode in which the number of times of power supply to the electrothermal transducer is small. The ink jet recording apparatus according to claim 3, wherein a high recording mode is selected. 5. The printing head performs a printing operation on a printing medium by reciprocating relative to the printing medium in a main scanning direction and moving in a sub-scanning direction that intersects the main scanning direction. The ink jet recording apparatus according to any one of claims 1 to 4, wherein: 6. The ink jet recording apparatus according to claim 6, wherein the number of times of energization calculation means calculates the number of times of energization of the electrothermal transducer required for the printing operation for each main scan based on the image data. apparatus. 7. The recording head performs a recording operation only at the time of forward movement in the main scanning direction, the number-of-energization calculating means calculates the number of energization at the time of forward movement, and the mode setting means responds to each calculation result. 7. An ink jet recording apparatus according to claim 1, wherein a recording mode having a different ejection frequency is set. 8. The printing head performs a printing operation at the time of forward movement and backward movement in the main printing scanning direction, and the number-of-energizations calculating means calculates the number of times of powering to be performed at the time of forward movement and backward movement. 8. The ink jet recording apparatus according to claim 1, wherein the mode setting means sets a recording mode having an ejection frequency according to each calculation result. 9. The ink jet recording apparatus according to claim 1, wherein the number of times of energization calculation means calculates the number of times of energization of the electrothermal transducer required for a one-line printing operation.