JPH1120148A - Method for controlling ink jet recorder and the recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance an efficiency of recording by changing the degree for limiting a heating amount of a head in response to an environmental temperature or a difference between a head temperature and the environmental temperature, thereby preventing discharge fault of ink or damage of the head. SOLUTION: Detection signals are output from head and environmental temperature sensors 1 and 5 during a printing operation, head and environmental temperatures Th, Tr are respectively decided by head and environmental temperature detectors 4 and 6, and sent to an excess temperature rise detector 7. The detector 7 compares the temperature Th with a threshold value T0 of a reference temperature of whether an excess temperature rise preventing sequence will be executed or not. At the time of detecting T0<Th, the detector 7 sends a signal to a print controller 9 and head drive controller 8 in advance to conduct printing for only print data of scanning. After the printing is finished, printing of next scanning is paused. Simultaneously, by referring to a table corresponding to an optimum interrupting time with respect to a difference from the temperature Tr or the head and environmental temperatures Th, Tr, the interrupting time of printing is decided. And, the detector 7 counts up the interrupting time.

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 capable of obtaining a high-quality image on a recording material, and more particularly, to insolubilizing a recording ink and a coloring material in the recording ink on a recording medium. The present invention relates to an ink jet recording apparatus that discharges an image quality improving agent to be aggregated.

[0002] The present invention is applicable to all devices that use thermal energy to record on paper, cloth, leather, nonwoven fabric, OHP paper, and other recording media such as metal. Specific examples of applicable equipment include office equipment such as printers, copiers, and facsimiles, and industrial production equipment.

[0003]

2. Description of the Related Art Conventionally, ink jet recording methods have been used in printers, copiers, and the like in terms of low noise, low running cost, easy downsizing of apparatuses, and ease of colorization.

An ink jet recording apparatus is an apparatus which forms an image by ejecting ink from nozzles and depositing ink on recording paper. In order to improve the recording speed, a recording element for discharging ink is provided on a recording head. And a plurality of ink discharge ports and flow paths (nozzles) are integrated and arranged (hereinafter also referred to as a multi-head), and a multi-head having a plurality of multi-heads for color is used.

FIG. 15 is a schematic perspective view of such an ink jet recording apparatus. The recording medium 106 inserted into the sheet feeding position of the recording apparatus 100
By 9 the sheet is conveyed to a recordable area of the recording head unit 103. A platen 108 is provided below the recording medium in the recordable area. Carriage 101
Is configured to be movable in a direction defined by two guide shafts, a guide shaft 104 and a guide shaft 105,
The recording area is scanned back and forth. On the carriage 101, a print head unit that includes a print head that discharges a plurality of color inks and an ink tank that supplies ink to each print head is mounted. The plurality of color inks provided in the ink jet recording apparatus of this example are four colors of black (Bk), cyan (C), magenta (M), and yellow (Y). A recovery unit 110 is provided at the lower part of the left end of the area where the carriage can move, and can cap the ejection opening of the recording head during non-printing. This left end is called the home position of the recording head.

Reference numeral 107 denotes a switch unit and a display element unit.
The switch unit is used for turning on / off the power of the recording apparatus, setting various recording modes, and the like, and the display element unit serves to display the state of the recording apparatus.

FIG. 16 is a perspective view of the recording head unit 103. In this example, ink tanks 20 corresponding to black, cyan, magenta, and yellow inks are shown.
Are configured to be exchangeable independently of each other.

The carriage 101 has Bk, C, M, Y
A recording head 102 provided with a plurality of ejection ports for ejecting the ink and a nozzle (flow path) communicating with each of the ejection ports, a tank 20B for Bk, a tank 20C for cyan, a tank 20M for M, and a tank 20M for Y The tank 20Y is loaded. Each tank is connected to a recording head via a connection, and each ink is supplied to each nozzle from this tank.

In addition to such a configuration, for example, a tank having four-color tanks having an integral structure and a tank having C, M, and Y tanks having an integral structure independent of Bk are known.

FIG. 17 is a schematic enlarged cross-sectional view showing the vicinity of the heating element of the recording head. A heating element 30 as an electric / heat converter is arranged corresponding to each ink ejection port 23. A recording apparatus equipped with an ink jet recording head having such a configuration employs a recording method in which a drive signal corresponding to recording information is applied to a heating element of the head to discharge ink from nozzles. The heating element 30 is configured to be independently drivable to all nozzles. The ink in the nozzle, which is rapidly heated by the heat generated by the above-described heating element, forms bubbles due to film boiling, and the ink droplets 35 are ejected toward the recording medium 31 as shown in FIG. Form characters and images on the recording medium.
At this time, the volume of the ejected ink droplet of each color is 15 to 10
It is about 0 ng.

Each of the plurality of discharge ports 23 of the recording head is provided with an ink flow path (nozzle) communicating with the discharge port, and is located on the rear side (upstream side) of the portion where the ink flow path is provided. Is provided with a common liquid chamber 32 for supplying ink to these ink flow paths. In the ink flow path corresponding to each of the ejection ports, a heating element 30 that generates thermal energy used to eject ink droplets from these ejection ports is provided.
And an electrode wiring (not shown) for supplying power thereto. These heating elements 30 and electrode wirings are formed on an element substrate 33 made of silicon or the like by a semiconductor film forming technique. Further, a protective film 36 is formed on the heating element 30 so that the ink does not directly contact the heating element. Furthermore, the above-described discharge port is formed by stacking a partition wall 34 made of resin, glass material, or the like on the element substrate.
An ink channel, a common liquid chamber, and the like are configured.

As described above, the recording method using a heating element is called a bubble jet recording method because it uses bubbles formed by applying thermal energy when ejecting ink droplets.

FIG. 18 shows a typical drive block diagram used in an ink jet recording apparatus as described above.

Data of characters and images to be recorded (hereinafter referred to as image data) is input from a host computer to a reception buffer 401 of the recording device. Further, data for confirming whether data is correctly transferred and data for notifying the operation state of the recording apparatus are output from the recording apparatus to the host computer. The data in the reception buffer 401 is C
Under the control of the PU (control unit) 402, the memory unit 403
And temporarily stored in a RAM (random access memory).

A mechanical control unit 404 includes a CPU 402
In response to a command from the controller, a mechanical unit 405 such as a carriage motor or a line feed motor is driven. The sensor / SW control unit 406 sends signals from a sensor / SW unit 407 including various sensors and SWs (switches) to the CPU 402.
Control section to send to The display element control unit 408 controls the LE of the display panel group by a command from the CPU.
It is a control unit for controlling the display element unit 409 including D and a liquid crystal display element. Recording head control unit 4
Reference numeral 10 controls the recording head 411 according to a command from the CPU. A control unit senses temperature information indicating the state of the recording head 411 and transmits it to the CPU 402.

In the ink jet recording apparatus using heat as described above (also referred to as a thermal ink jet printer), the technology for increasing the speed of the ink jet printer has been further advanced, and as a method for increasing the speed, an ink jet printer in one head is used. Techniques such as increasing the number of nozzles and increasing the driving frequency are known.

A point to be considered in a thermal ink jet printer is an excessive temperature rise of the recording head. In a thermal inkjet printer, not all of the energy input to the heating element in the head is consumed as energy for ejecting ink droplets, but much of the energy remains in the head as heat. For this reason, in the case of the configuration for further increasing the speed as described above, the amount of heat remaining in the head further increases.

In a thermal ink jet printer, if the temperature rise of the head and ink is left unchecked, not only the state of ink droplet ejection becomes unstable, but also the ink droplet ejection becomes impossible due to excessive temperature rise, The head may be physically destroyed.

For this reason, conventionally, for driving and printing control of a thermal ink jet printer, there are several methods for preventing the temperature of the head from rising. For example, the head temperature is detected and the recording is interrupted for a predetermined time when it is detected that the temperature is equal to or higher than a predetermined temperature, or when the head temperature is detected during the recording of one line and the temperature reaches the first specified temperature (temperature rise). In this case, the recording is interrupted after the recording of the line is completed, and the recording is resumed when the head temperature falls to or below the second specified temperature (Japanese Patent Publication No. 03-4394). I have.

There is also a method of preventing the temperature of the head from being increased by using other parameters in addition to the temperature of the head. For example, there is known a method (US Pat. No. 4,910,528) in which control is performed based on both a head temperature detection result and a prediction result of a temperature rise amount by pre-reading a print duty of data to be printed from now on.

[0021]

However, since the rate of temperature rise or temperature drop largely depends on the ambient temperature around the head and the head temperature at that time, the ratio is not always constant. Therefore, for example, in the above-described method in which recording is interrupted when the head temperature exceeds a threshold value, the interruption time must be considered more than necessary for safety, and the overall recording speed is reduced. There was a case. On the other hand, in the means for predicting the print duty and estimating the amount of temperature rise, setting the prediction parameter in consideration of the rate of temperature rise in a high-temperature environment causes excessive control in a normal-temperature environment. In some cases, printing speed may be reduced.

When the temperature control in the thermal ink jet printer is performed by using the temperature detection result of the temperature sensor provided on the element substrate of the head, the temperature sensor itself has a large error due to manufacturing variations. There is a problem that it is difficult to directly use the output value of the temperature sensor as the head temperature. This can be alleviated to some extent by suppressing variations in the manufacturing of the temperature sensor, but it increases the cost of the head. Therefore, in many cases, the output value of the temperature sensor is corrected, and the temperature of the thermal inkjet printer is controlled using the correction result. However, this correction is complicated, and depending on the correction conditions, even after the correction, a certain amount of error may be detected as a detection value, and the purpose of the control at the time of the detection of the excessive temperature rise may not be sufficiently fulfilled. Was.

SUMMARY OF THE INVENTION The present invention solves the above-described problems. An object of the present invention is to more stably control the temperature rise of a head of a thermal ink-jet printer by recording, thereby stabilizing discharge and preventing non-discharge. Prevention, as well as thermal damage to the head.

[0024]

Means for solving the above-mentioned problems include means for detecting the head temperature of the ink-jet head and the environmental temperature outside the head by using means for detecting the head temperature of the ink-jet head. In the control method of the ink jet recording apparatus for limiting the heat generation amount of the head when it is recognized that the degree of the limitation is changed according to the environmental temperature or the difference between the head temperature and the environmental temperature. A control method of the ink jet recording apparatus, or a means for detecting a head temperature of the ink jet head, a means for detecting an environmental temperature outside the head, Means for limiting the amount of heat generation, and control means for changing the degree of the limitation according to the environmental temperature or the difference between the head temperature and the environmental temperature An ink jet recording apparatus, comprising a.

According to such a configuration, by preventing excessive temperature rise of the ink jet head, it is possible to prevent defective ink ejection and damage to the head, and it is not necessary to perform more than necessary standby time or divided recording. Recording efficiency can be improved, and high-speed recording can be achieved as a whole.

[0026]

Embodiments of the present invention will be described below with reference to the drawings. Note that the above-described configuration can be applied to the present invention except for the features of the device configuration, the head configuration of the device, and the drive block that are characteristic of the present invention, and therefore the description thereof is omitted here.

(First Embodiment) A first embodiment of the present invention will be described in detail with reference to FIGS.

FIG. 1 is a control block diagram of the present invention for detecting and controlling the head temperature and the ambient temperature of the head. Inside the thermal inkjet head, a heater board (element substrate) which is a Si substrate on which a heating resistor for discharging ink, an electric circuit for controlling the heating resistor, and a driving element are arranged. In the drawing, reference numeral 1 denotes a head temperature detection sensor provided on the heater board. In the present embodiment, the temperature detection is performed by using the temperature characteristics of the output voltage of the diode as the head temperature detection sensor. However, a temperature sensor using the temperature characteristics of the resistance value of the electric resistor or any other device may be used. Can be. Reference numeral 2 denotes a heating resistor for discharging recording ink droplets, and reference numeral 3 denotes a signal line (flexible wiring) for exchanging signals between the head and the apparatus main body.

Reference numeral 4 denotes a head temperature detection circuit, a detection circuit for receiving an output signal from a head temperature sensor, an A / D conversion circuit for converting the data into digital data, and a format capable of operating the result of the A / D value for control. It is composed of a temperature data conversion / correction circuit and the like. The results here are treated as head temperatures and various controls such as PWM control (pulse width control) of head drive pulses are performed.

Reference numeral 5 denotes a head environment temperature sensor for detecting the temperature around the head (ink). The sensor is provided on a substrate provided on a carriage on which the head is mounted, and uses a thermistor or the like. . Reference numeral 6 denotes an environmental temperature detection circuit, which comprises a circuit for detecting the output of the thermistor, an A / D conversion circuit, a correction / conversion circuit, and the like, as in the case of the head temperature detection section, and treats the output result therefrom as the environmental temperature.

Reference numeral 7 denotes a head overheat detection control unit which determines whether or not to perform a head overheat prevention sequence based on a head temperature detection result from the head temperature detection circuit unit 4 and an environmental temperature result from the environmental temperature detection circuit unit 6. I do. Here, the head temperature rise prevention sequence is a sequence for preventing instability of ejection, non-ejection, and damage or destruction of the head due to the temperature rise of the head. A sequence for preventing a temperature rise such as lowering the frequency is known, and any sequence may be used here.

The condition of the combination of the head temperature and the environmental temperature as a criterion for judging whether or not to start the temperature rise prevention sequence will be described later. Hereinafter, the conditions for starting and ending the temperature rise prevention sequence will be described. Either one or both cases are shown.

Reference numeral 8 denotes a head drive control unit, which determines the drive condition of the heating resistor in the print head based on the detected value of the head temperature from the head temperature detection circuit 4 and the information from the print control unit 9 and drives. A signal is generated, and a drive control of a head warming heater (not shown) is performed.

Reference numeral 9 denotes a print control unit which determines which nozzle should be actually driven and which ink droplet should be ejected at what timing based on print data from the host or conditions such as a print mode set by the user on the panel or the like. It has a function of deciding, and determining a drive timing and a drive amount of a drive motor or a paper feed motor for driving the carriage in accordance with the determination.

Hereinafter, a temperature control process performed by the printer according to the present embodiment will be described with reference to FIG. During the printing operation, a detection signal is always output from the head temperature detection sensor 1 (S1).
01), converted and corrected by the temperature detection circuit of the main body (S10)
2), the head temperature Th is determined (S103). Then, the head temperature Th is sent to the excessive temperature rise detecting section 7.

Similarly, a detection signal is output from the environmental temperature detecting sensor 5 (S113), and the environmental temperature detecting circuit 6
Are converted and corrected (S114), and the environmental temperature Tr is determined (S115). Then, the environmental temperature Tr is sent to the excessively high temperature detecting section 7.

In the excessive temperature rise detecting section 7, a threshold temperature T0 which is a reference temperature for determining whether or not to carry out the above-mentioned temperature rise prevention sequence.
Is compared with the head temperature Th (S104), and T0 <Th
Is detected, a predetermined signal is sent to the print controller 9 and the head drive controller 8. When the print control unit 9 and the head drive control unit 8 receive the signal, they print only the print data of the scan (line) (S10).
7, S108), and after this printing, the printing of the next scan is paused.

Simultaneously with detection of T0 <Th, the interruption time t0 is determined with reference to the interruption time t table for the environmental temperature Tr as shown in FIG. 3 (S105) (S1).
06). On the other hand, when the interruption of printing is started, the excessive temperature rise detecting section 7 starts a suspension time timer for measuring the suspension time (S109) and counts up the suspension time t. When the interruption time t becomes t> t0 (S111), a print restart command is sent to the print controller 9 and the head drive controller 8 to restart printing (S112).

Hereinafter, a method of setting the interruption time by the temperature control processing of this embodiment will be described. The amount of temperature decrease of the recording head when the recording head whose temperature has been raised is stopped after recording is left largely depends on the difference (ΔT = Th−Tr) between the recording head temperature Th and the surrounding environmental temperature Tr (ΔT = Th−Tr) and the elapsed time. By the way, since the temperature at which the recording head causes a discharge failure or the temperature at which the head is thermally damaged can be determined by the absolute temperature, the above-described threshold temperature T0 can be made substantially constant. For this reason, the temperature drop characteristic of the head largely depends on the environmental temperature Tr. When the environmental temperature Tr is low, the temperature drops quickly, and when the environmental temperature Tr is high, the temperature drops slowly. Therefore, the print interruption time t0 needs to be lengthened when the environmental temperature Tr is high, and can be shortened when it is low.

In this embodiment, the interruption time is set in accordance with a table as shown in FIG. 3 in which the optimum interruption time t0 is associated with the environmental temperature Tr in advance. In the table of FIG. 3, Tr1 <Tr2 <... <Trn <.
1 <t2 <... <Tn <.
The higher the environmental temperature Tr, the longer the interruption time t0.

As a result, instability of printing in a high-temperature environment due to shortage of the interruption time that occurs when a constant interruption time that does not depend on the environmental temperature is used as in the related art, and excessive lengthening in a low-temperature environment It is possible to perform stable printing even in various environments while preventing the interruption of printing at the same time and preventing the printing speed from lowering as much as possible.

In this embodiment, after the detection of the excessive temperature rise, the printing of the scan is completed, and then the printing is interrupted (scan stop).
However, even during printing, control is performed to stop the heating of the discharge heater of the head at the same time as the detection of Th> T0 and restart the remaining printing again after a certain period of time. Control may be performed such that printing is resumed after performing an idle scan for a fixed time after interruption, and even in such a case, the heat interruption time is determined by the environmental temperature Tr as in the present embodiment. A similar effect can be obtained by determining.

(Second Embodiment) In the first embodiment, the interruption time is selected based on the environmental temperature Tr. However, in the present embodiment, not only the environmental temperature Tr but also the head temperature is determined. It is an embodiment in which an interruption time is set based on a value taken into consideration.

The configuration of the control block in this embodiment is the same as that in FIG. FIG. 4 is a diagram illustrating a temperature control process performed by the printer of the present embodiment. The difference from the first embodiment is the step of referring to the interruption time t0, and other steps are the same as those of the first embodiment.

In the previous embodiment, the interruption time t0 was determined based on the environmental temperature Tr.
In order to appropriately determine 0, the interruption time t0 is determined based on the difference ΔT between the recording head temperature Th and the surrounding environmental temperature. As described in the previous embodiment, the amount of temperature decrease of the print head greatly depends on the difference between the temperature Th of the print head and the surrounding environmental temperature (ΔT = Th−Tr) and the elapsed time. When ΔT is large, the temperature falls rapidly, and when ΔT is small, the temperature falls slowly. Therefore, the print interruption time t0 can be shortened when ΔT is large, and must be lengthened when ΔT is small. In the present embodiment, step S205 in FIG.
The interruption time is set in accordance with a table as shown in FIG. 5 in which the optimal interruption time t0 is previously associated with ΔT.

In the table of FIG. 5, ΔT1 <ΔT2 <.
Tn <..., T1>t2>...>Tn>..., And when ΔT is large, the interruption time t is shortened.

As described above, since the table defining the relationship between ΔT and the print interruption time is used, an appropriate interruption time can be set with higher accuracy.

(Third Embodiment) The third embodiment is an example in which the operation control of the printer after detecting an excessive temperature rise in which the head temperature is higher than the threshold temperature is different from the first and second embodiments. . In this embodiment, the configuration of the drive control block is the same as that of the previous embodiment (FIG. 1).

The temperature control process of this embodiment will be described with reference to FIG.

As in the first embodiment, a detection signal is always output from the head temperature detection sensor 1 during the printing operation (S6).
01), converted and corrected by the temperature detection circuit of the main body (S60)
2), the head temperature Th is determined (S603). Then, the head temperature Th is sent to the excessive temperature rise detecting section 7.

Similarly, a detection signal is output from the environmental temperature detection sensor 5 (S612), and the environmental temperature detection circuit 6
Are converted and corrected (S613), and the environmental temperature Tr is determined (S614). Then, the environmental temperature Tr is sent to the excessively high temperature detecting section 7.

The excessive temperature detecting section 7 has a threshold temperature T0 as a reference temperature for determining whether or not to perform the above-described temperature raising prevention sequence.
Is compared with the head temperature Th (S604), and T0 <Th
Is detected, a predetermined signal is sent to the print controller 9 and the head drive controller 8. When the print control unit 9 and the head drive control unit 8 receive the signal, they print only the print data of the scan (line) (S60).
7, S608), the printing of the next scan is divided into a plurality of times and printing is performed. At this time, the maximum printing width (maximum number of usable nozzles) n of the divided printing is determined with reference to a table showing the relationship with the environmental temperature Tr as shown in FIG. 7 (S605) (S606).

FIG. 8 shows the state of division printing at this time. An area 10 indicates an image area of the original print width (the number of nozzles) N in one scan. Here, the number of nozzles of the head 11 and the printing width are the same, but in reality, it corresponds to the number of nozzles used for printing in the scan, and the number of nozzles of the head 11 and the printing area width N are always It is not limited to being the same. In the first scan after detecting that the head temperature Th has exceeded the threshold temperature T0, n in the upper part of the figure among the total number N of nozzles of the head 11 is shown.
Printing is performed using only the nozzles, and printing in the printing area 10a is completed (S609). Thereafter, the paper is fed by the print width n (S610), and the print area 10 is printed in the second scan.
b is printed. At this time, if the relationship between the head temperature and the threshold temperature at this time is Th> T0, printing is performed again with the print width n according to the environmental temperature Tr.

Hereinafter, a method of dividing the print area by the temperature control processing according to the present embodiment will be described.

The amount of temperature rise of the head by printing is determined by the environmental temperature Tr.
Greatly affected. When the same printing is performed at different environmental temperatures Tr, the lower the Tr, the smaller the amount of temperature rise.
The higher the temperature, the greater the temperature rise. In the embodiment, the maximum number of usable nozzles is limited according to the environmental temperature as shown in the table of FIG. In the table of FIG. 7, Tr1 <Tr2 <... <Trn
<..., n1>n2>...>nn> ..., the maximum number of usable nozzles is small when the ambient temperature Tr is high, and the maximum number of usable nozzles is low when the environmental temperature Tr is low. Is increasing. As a result, printing can be performed using the maximum number of nozzles at each environmental temperature, preventing excessive printing interruption by the conventional split printing method that does not depend on the environmental temperature, preventing the printing speed from decreasing as much as possible, Stable printing can be obtained even in various environments.

In this embodiment, only the case of one-pass printing has been described. However, a similar method can be used in the case of multi-pass printing which is known as an ink-jet printing method. 9 and 10 show examples of pass printing)
Shown in

FIG. 9 shows, for comparison, an example of conventional multi-pass printing in which division printing is not performed in consideration of the environmental temperature and the head temperature according to the present invention. As described above, the multi-pass printing is to perform printing by dividing the number of nozzles N of the head by a predetermined number of nozzles. In this example, the necessary number of nozzles is divided into two and the number of nozzles of the head is divided into two to scan three times. The width N has been completed. In the first scan (A), recording is performed by thinning out the number of print dots to 領域 in the print width N / 2 area using the lower N / 2 nozzles of all the nozzles of the head.

In the second scan (B), using all the nozzles N of the head, the number of print dots is reduced to １ ／ in the area of the recording width N.
And record it. By this scan, in the area where the printing was performed in the first scan, 100% printing is achieved by performing the １ ／ thinning printing again.

Subsequently, in the third scan (C), the number of print dots is set to 1 in an area of a print width N / 2 where printing is not completed by using upper N / 2 nozzles among all nozzles of the head. / 2 is recorded.

In this case, since the number of divided nozzles is fixed at N / 2 without considering the environmental temperature Tr, even if the number of divided nozzles is divided into N / 2, the temperature may be further increased.

On the other hand, in the example shown in FIG. 10, when the head temperature exceeds the threshold position temperature, the maximum number of nozzles that can be used is limited, and the division method of divided printing is changed according to the limited number. ing. Here, printing is performed with the maximum number n of nozzles that can be used in the first scan, 2n printing is performed in the second scan, and printing is performed in the third scan.

[0062]

[Outside 1] The remaining area is recorded by the nozzles of (N−n) in the fourth scan. For this reason,
It is possible to improve the recording speed while preventing an excessive temperature rise of the head.

(Fourth Embodiment) In the third embodiment, the environmental temperature Tr is used to determine the maximum number of usable nozzles in the case of performing divided printing. In the present embodiment, not only the environmental temperature Tr but also the environmental temperature Tr is used. Similar to the second embodiment, division printing is controlled with higher accuracy by using the difference (ΔT = Th−Tr) between the recording head temperature Th and the surrounding environmental temperature Tr. FIG. 11 shows the procedure of the temperature control process of the present embodiment. Steps similar to those of the third embodiment are denoted by the same reference numerals, and description thereof is omitted here. How steps S620 and S
A method of determining the maximum number of usable nozzles in 606 will be described.

When the same printing is performed at different ΔT, ΔT
The larger the value, the smaller the amount of temperature rise, and the smaller the ΔT, the larger the amount of temperature rise. In the present invention, as shown in the table of FIG. 12, the number of nozzles used is limited by the environmental temperature. In the table of FIG. 12, ΔT1 <ΔT2 <... <ΔTn <..., n1 <n2
The relationship of <... <nn <... is such that when ΔT is large, the number of usable nozzles is large, and when ΔT is small, the number of nozzles used is small. As a result, printing can be performed using the maximum number of nozzles at each environmental temperature, preventing excessive printing interruption by the conventional split printing method that does not depend on the environmental temperature, preventing the printing speed from decreasing as much as possible, Stable printing can be obtained even in various environments.

Even when the determination is made using ΔT as in the present embodiment, the present invention can be applied to the multi-pass printing described in the third embodiment.

(Fifth Embodiment) This embodiment will be described with reference to a control diagram block diagram of FIG. In FIG. 13, the detection of the head temperature and the detection of the environmental temperature are the same as those in the above-described embodiment, and thus the description thereof is omitted. In the present embodiment, the duty D (= the actual number of print dots / the total number of print areas / the entire print area) is developed on the print buffer of the print control unit 9 simultaneously with the detection of the head temperature and the environmental temperature, and is printed in the next scan from the next scan print data. Data count). Head temperature is Th>
At T0, the print duty D of the next scan is
If the print duty D is larger than the threshold value Dn at the time of Trn by referring to the environmental temperature Tr-print duty threshold Dth conversion table shown in FIG.
The printing method is switched to the division printing as follows.
The divided printing referred to here is a method of reducing the printing duty by restricting the nozzles used as described in the third embodiment, or completing the image by scanning the printing area a plurality of times while using all the nozzles, This refers to a method of lowering the substantial print duty per scan (regardless of whether or not paper is fed until the image in the print area is completed).

Here, the printing method described in this embodiment will be described in more detail. In the third embodiment, the number of nozzles to be used is limited regardless of the print amount in the print scan. However, in this case, the print duty is low and even if the print data does not actually raise the temperature much, the print is performed. The duty (the number of nozzles used) may be excessively limited. In this embodiment, the relationship between the environmental temperature Tr and the printing duty threshold value Dth as shown in FIG.
rn <..., D1>D2>...>Dn>. Where Dn
Is set as a printing duty corresponding to a printable temperature increase amount at the environmental temperature Tr. By comparing this Dn with the print duty D, the print duty in the actual scan is always set to be equal to or less than Dn, and when the print duty D is equal to or less than Dn, the printing that has occurred in the second embodiment is performed. The speed does not decrease, and printing can be continued at a stable and appropriate printing speed.

Although the method of calculating the print duty D is not described in detail in the above description, the calculation may be performed by the printer itself or the function may be given to the host.

Regarding the count of the print duty D, all data may be sequentially counted, but the vertical, horizontal or both are divided into a plurality of blocks, and the print duty is counted for each block. A method of calculating the sum can be used. Further, the present invention does not substantially affect the present invention even if the number of nozzles used in actual printing is a control method for each specific block, and the present invention is not limited to this.

Also in this embodiment, not only the environmental temperature Tr but also the environmental temperature Tr-print duty threshold Dth table used in step S135, ΔT-
By using the printing duty threshold Dth table,
Control based on ΔT can be performed.

[0071]

According to the present invention as described above, by preventing excessive temperature rise of the ink jet head, it is possible to prevent defective ink ejection and damage to the head, and to perform unnecessary standby time and divided recording. Since there is no need, recording efficiency can be improved, and high-speed recording can be achieved as a whole.

[Brief description of the drawings]

FIG. 1 is a control block diagram of the present invention for detecting and controlling a head temperature and a head peripheral environment temperature.

FIG. 2 is a flowchart illustrating a temperature control process according to the present invention.

FIG. 3 is a table of an interruption time t with respect to an environmental temperature Tr.

FIG. 4 is a flowchart illustrating a temperature control process according to the present invention.

FIG. 5 is a table in which an optimum interruption time t0 is associated with ΔT in advance.

FIG. 6 is a flowchart illustrating a temperature control process according to the present invention.

FIG. 7 is a table of the maximum number of usable nozzles with respect to the environmental temperature Tr.

FIG. 8 is a schematic diagram for explaining a state of divided printing.

FIG. 9 is a schematic diagram for explaining multi-pass printing.

FIGS. 8 and 9 are explanatory diagrams of a third embodiment of the present invention.

FIG. 11 is a flowchart illustrating a temperature control process according to the present invention.

FIG. 12 is a table of the maximum number of usable nozzles with respect to ΔT.

FIG. 13 is a flowchart illustrating a temperature control process according to the present invention.

FIG. 14 is a table of a threshold duty with respect to an environmental temperature Tr.

FIG. 15 is a schematic perspective view illustrating the configuration of an ink jet recording apparatus.

FIG. 16 is a schematic perspective view for explaining a recording head unit.

FIG. 17 is a schematic enlarged cross-sectional view of the vicinity of a heating element of a recording head.

FIG. 18 is a drive block diagram used in an ink jet recording apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Head temperature detection sensor 2 Heating resistor 3 Signal line (flexible cable) 4 Head temperature detection circuit part 5 Environmental temperature detection sensor 6 Environmental temperature detection circuit part 7 Excessive temperature rise detection control part 8 Head drive control part 9 Print control part

Claims (18)

[Claims] An ink jet head for limiting a heat generation amount of a head when it is recognized that the head temperature is equal to or higher than a predetermined threshold value by using means for detecting a head temperature of the ink jet head and an environmental temperature outside the head. A method for controlling a recording apparatus, comprising: changing the degree of the restriction according to the environmental temperature or a difference between a head temperature and the environmental temperature. 2. The method according to claim 1, wherein the degree of the restriction is performed by changing a parameter for determining the restriction amount according to the environmental temperature or a difference between the head temperature and the environmental temperature. . 3. The method according to claim 2, wherein the parameter is selected from a difference between a head temperature and an environmental temperature or a table in which the environmental temperature is associated with the limit amount. . 4. The limitation of the heat generation amount includes interrupting printing for a predetermined time, performing thinning printing, limiting the maximum number of usable nozzles of the head, or interrupting printing until the head temperature falls below a predetermined temperature. 2. The method according to claim 1, wherein at least one of the steps is performed. 5. The method according to claim 2, wherein the parameter for determining the limit amount is an interruption time for limiting a heat generation amount of the head by interrupting printing for a predetermined time. 6. The method according to claim 2, wherein the parameter for determining the limit amount is a thinning rate for limiting a heat generation amount of the head by performing thinning printing. 7. The control of the ink jet printing apparatus according to claim 2, wherein the parameter for determining the limit amount is a maximum number of usable nozzles for limiting the heat generation amount of the head by limiting the number of nozzles used in the head. Method. 8. The ink jet printing apparatus according to claim 2, wherein the parameter for determining the limit amount is a predetermined temperature for limiting the heat generation amount of the head by interrupting the printing until the head temperature becomes equal to or lower than the predetermined temperature. Control method. 9. The method according to claim 1, wherein the head generates bubbles based on a film boiling phenomenon in the ink by the generated heat, and discharges the ink from a discharge port by a pressure at the time of the generation of the bubbles. . 10. A means for detecting a head temperature of an ink-jet head, a means for detecting an environmental temperature outside the head, and limiting a heat generation amount of the head when it is recognized that the head temperature is equal to or higher than a predetermined threshold value. And a control unit for changing the degree of the restriction in accordance with the environmental temperature or a difference between the head temperature and the environmental temperature. 11. The control unit according to claim 10, wherein the control unit changes a degree of the limit by changing a parameter for determining a limit amount according to the environmental temperature or a difference between the head temperature and the environmental temperature. Inkjet recording device. 12. The ink jet recording apparatus according to claim 11, wherein a table in which the difference between the head temperature and the environmental temperature or the environmental temperature is associated with the limit amount is held. 13. The method according to claim 1, wherein the heat generation amount is limited by interrupting printing for a predetermined time, performing thinning printing, limiting the maximum number of usable nozzles of the head, or interrupting printing until the head temperature falls below a predetermined temperature. The inkjet recording apparatus according to claim 10, wherein at least one of the operations is performed. 14. A parameter for determining the limit amount,
12. The ink jet recording apparatus according to claim 11, wherein the printing is stopped for a predetermined time to limit the amount of heat generated by the head. 15. A parameter for determining the limit amount,
12. The ink jet recording apparatus according to claim 11, wherein the thinning rate is a thinning rate that limits a heat generation amount of the head by performing the thinning printing. 16. A parameter for determining the limit amount,
The ink jet recording apparatus according to claim 11, wherein the number of usable nozzles of the head is limited so as to limit the amount of heat generated by the head. 17. A parameter for determining the limit amount,
2. A predetermined temperature for limiting the amount of heat generated by the head by suspending printing until the head temperature falls below a predetermined temperature.
2. The ink jet recording apparatus according to 1. 18. The ink jet recording apparatus according to claim 11, wherein the head generates bubbles based on a film boiling phenomenon in the ink by the generated heat, and discharges the ink from a discharge port by a pressure when the bubbles are generated.