JPH0531918A - Ink jet recording device - Google Patents

Abstract

PURPOSE:To provide an ink jet recording device which dispenses with any special fixing tool even during the replacement of a recording head or a substrate with an electric mounting, and ensures precise detection of the temperature of the recording head without increasing cost or complicating a working process due to the addition of a means for measurement of a correction value for the recording head and reading data from a main device system. CONSTITUTION:A detection temperature Td (step S230) obtained by a temperature detection member provided at a recording head is automatically calibrated (steps S240, S250) at a point of time when a non-recording time passes beyond a specified time setting (step S150), using the detection temperature Tt (step S200) of a reference temperature detection member provided on a main device system.

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 for recording by ejecting ink from a recording head onto a recording material.

[0002]

2. Description of the Related Art A recording device such as a printer, a copying machine or a facsimile is constructed so as to record an image composed of dot patterns on a recording material such as paper or a thin plastic plate based on image information. There is. The recording device can be divided into an inkjet type, a wire dot type, a thermal type, a laser beam type, and the like, depending on the recording type. Among them, the inkjet type (inkjet recording device) is
An ink (recording liquid) droplet is ejected and ejected from the ejection port of the recording head, and the ink droplet is adhered to a recording material for recording.

In recent years, a large number of recording devices have been used, and high speed recording, high resolution, high image quality, low noise, etc. are required for these recording devices. As an example of a recording device that meets such a demand, the inkjet recording device can be cited. In an inkjet recording device that performs recording by ejecting ink from the recording head,
The stabilization of the ink ejection and the stabilization of the ink ejection amount required to satisfy the above requirements are largely affected by the temperature of the ink in the ejection portion. That is, if the temperature of the ink is too low, the viscosity of the ink will be abnormally lowered and it will not be possible to eject with normal ejection energy. Conversely, if the temperature is too high, the ejection amount will increase and the ink will overflow on the recording paper. This leads to a decrease in quality.

For this reason, in the conventional ink jet recording apparatus, a temperature sensor is provided in the recording head section, and the method for controlling the temperature of the ink in the ejection section within a desired range based on the temperature detected by the recording head and the ejection recovery. A method of controlling the process was adopted. As the heater for controlling the temperature, a heating heater member joined to the recording head portion or an ink jet recording for recording by forming flying droplets by using thermal energy is used. In a device, that is, a device that ejects ink droplets by bubble growth due to film boiling of ink, the ejection heater itself may be used. In addition, when the above-mentioned discharge heater is used, it is necessary to energize so that foaming does not occur.

In a recording apparatus that obtains ejected ink droplets by forming bubbles in solid ink or liquid ink by using thermal energy, the ejection characteristics greatly change depending on the temperature of the recording head. The temperature control of the inks of the printhead and the printhead, which greatly affects it, is particularly important.

However, since the temperature detecting members of the print heads, which are important in controlling the temperature of the print heads, usually have variations, the detected temperatures may differ greatly from print head to print head. Therefore, at the time of shipment of the recording apparatus, a method of calibrating or adjusting the temperature detecting member of the recording head or a method of providing the recording head itself with a correction value of the temperature detecting member and automatically mounting the recording apparatus on the recording apparatus main body The method of correction is taken.

[0007]

However, in the method of calibrating / adjusting the recording apparatus at the time of shipment, it is necessary to replace the recording head or, conversely, the electric mounting substrate of the main body. In that case, it becomes necessary to recalibrate and readjust, and it is necessary to prepare jigs and tools for that purpose. In addition, in order to give a correction value to the recording head itself, the correction value is measured for each recording head, a special memory means is required for the recording head, and a correction value reading detection means is also required on the main body side. Therefore, it is inconvenient in terms of cost and device configuration.

Therefore, the present invention does not require a special jig or tool even when the recording head or the electric mounting substrate is replaced, and the cost and process increase due to the measurement of the correction value of the recording head and the addition of the reading means of the main body. It is an object of the present invention to provide an ink jet recording apparatus that can accurately detect the temperature of a recording head without complicating the above.

[0009]

In order to achieve the above object, the present invention uses the reference temperature detecting member provided in the main body to detect the temperature of the temperature detecting member provided in the recording head at a predetermined timing. It is provided with a calibrating means for automatically calibrating.

More specifically, it has timer means for timing the non-recording period, and is for measuring the rate of change in temperature detected by the temperature detecting member when the non-recording period has passed a predetermined time or more. When the temperature change rate measuring means is provided and the temperature change rate is smaller than a predetermined value, or when the recording head replacement signal detecting means is provided and the recording head replacement signal is input, the detected temperature of the reference temperature detecting member is detected. The detection temperature of the recording head is adjusted to.

More preferably, the calibration means has a temperature correction amount calculation means for calculating a difference between the temperature detected by the print head and the temperature detected by the main body as a temperature correction amount, and the correction amount is equal to or more than a predetermined temperature. In the case of 1, the calibration error detection means for stopping the calibration is provided to prevent erroneous calibration.

Further, a preferable recording head in the present invention is one which causes a state change in ink by thermal energy and ejects the ink based on the state change.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a perspective view showing the configuration of a suitable inkjet recording apparatus IJRA to which the present invention is applied or applied. In FIG. 1, 5001 is an ink tank (IT), and 5012 is a recording head (IJH) coupled thereto. As shown in FIG.
And an ink tank 5012 and a recording head 5012 form an integrated replaceable cartridge (IJC).
The printer 5014 prints the cartridge (IJC).
Carriage (HC) for attaching to the main body, 5
Reference numeral 003 is a guide for scanning the carriage in the sub-scanning direction. Reference numeral 5000 denotes a platen roller for scanning the print object indicated by P in the main scanning direction. 502
4 is a temperature sensor for measuring the environmental temperature in the device.
The chip thermistor is provided on the electrical mounting substrate of the recording apparatus main body. The carriage 5014 is provided with a flexible cable (not shown) for supplying a signal pulse current for driving the head 5012 and a current for head temperature adjustment to the recording head 5012, and an electric cable for controlling the printer. It is connected to a printed board (not shown) equipped with a circuit (such as the temperature sensor 5024 described above).

FIG. 2 shows a replaceable cartridge.
Reference numeral 029 is a nozzle portion for ejecting ink droplets. Further, the ink jet recording apparatus IJRA having the above structure will be described in detail. This recording device IJRA is a drive motor 50.
Driving force transmission gears 5011, 5
The carriage HC that engages with the spiral groove 5004 of the lead screw 5005 that rotates via 009 has a pin (not shown) and is reciprocated in the directions of arrows a and b.
A paper pressing plate 5002 presses the paper against the platen 5000 in the carriage movement direction. 500
Reference numeral 7,5008 is a photocoupler and a lever for the carriage HC.
This is a home position detecting means for confirming the existence of 5006 in this region and switching the rotating direction of the motor 5013. Reference numeral 5016 is a member that supports a cap member 5022 that caps the front surface of the recording head. Reference numeral 5015 is a suction unit that sucks the inside of the cap, and performs suction recovery of the recording head 5012 through the opening 5023 in the cap.

5017 is a cleaning blade.
Reference numeral 019 denotes a member that allows the blade 5017 to move in the front-rear direction, and these members are supported by the main body support plate 5018. Needless to say, a known cleaning blade can be applied to this example instead of this form. Reference numeral 5021 is a lever for starting suction for suction recovery, which moves in accordance with the movement of the cam 5020 that engages with the carriage HC, and the driving force from the driving motor is transmitted by a known method such as clutch switching. The movement is controlled by means.

The capping, cleaning, and suction recovery are configured so that the desired processing can be performed at the corresponding positions by the action of the lead screw 5005 when the carriage HC reaches the home position side area. However, any of these can be applied to this example as long as the desired operation is performed at a known timing.

FIG. 3 shows the details of the recording head 5012, and a heater board 5100 formed by a semiconductor manufacturing process is provided on the upper surface of the support 5300. The heater board 5100 is provided with a temperature adjusting heater (heat raising heater) 5110 formed by the same semiconductor manufacturing process for keeping the recording head 5012 warm and controlling the temperature. Reference numeral 5200 is a wiring board disposed on the support 5300, and the wiring board 5200, the temperature control heater 5110, and the discharge (main) heater 511.
3 and 3 are wired by wire bonding or the like (wiring is not shown). The temperature control heater 5110 may be a support member 5300 or the like to which a heater member formed by a process different from the heater board 5100 is attached.

Reference numeral 5114 is a bubble generated by being heated by the discharge heater 5113. Reference numeral 5115 indicates the ejected ink droplet. Reference numeral 5112 is a common liquid chamber for the ejection ink to flow into the recording head.

FIG. 4 is a schematic view of an ink jet recording apparatus to which the present invention can be applied. Here, 8a is an ink jet cartridge, which has an ink tank portion in the upper part and a recording head 8b (not shown) in the lower part, and the recording head 8b.
A connector is provided for receiving signals for driving the. A carriage 9 positions and mounts four cartridges (each containing different color inks, such as black, cyan, magenta, and yellow). Further, a connector holder for transmitting a signal for driving the recording head and the like is provided and is electrically connected to the recording head 8b.

A scanning rail 9a extends in the main scanning direction of the carriage 9 and slidably supports the carriage 9.
Reference numeral c is a drive belt for transmitting a driving force for reciprocating the carriage 9. Further, 10c and 10d are pairs of conveying rollers which are arranged before and after the recording position by the recording head for nipping and conveying the recording medium, and 11 is a recording medium such as paper, which flattens the recording surface of the recording medium 11. It is pressed against a regulating platen (not shown). At this time, the recording head 8b of the inkjet cartridge 8a mounted on the carriage 9 projects downward from the carriage 9 and is located between the recording medium conveying rollers 10c and 10d, and the ejection port forming surface of the recording head portion is a platen (not shown). ) The recording material 11 is pressed against the guide surface and the surface of the recording material 11 faces in parallel. The drive belt 9c is driven by the main scanning motor 63, and the conveying roller pairs 10c and 10d are driven by the sub scanning motor 64 (not shown).

In the ink jet recording apparatus of this example, the recovery system unit is arranged on the home position side on the left side of FIG. 300 in the recovery unit
Is a cap unit provided corresponding to each of the plurality of ink jet cartridges 8c having the recording head 8b. The cap unit can slide in the left-right direction in the drawing as the carriage 9 moves, and can move up and down in the vertical direction. When the carriage 9 is at the home position, it is joined to the recording head 8b to cap the same, thereby preventing the ink in the ejection port of the recording head 8b from evaporating and thickening / fixing to cause ejection failure.

Further, in the recovery system unit, 500 is a pump unit communicating with the cap unit 300, and if the recording head 8b is defective in ejection, suction is performed by joining the cap unit 300 and the recording head 8b. Used to generate negative pressure during recovery processing. Further, in the recovery system unit, 401 is a blade as a wiping member formed of an elastic member such as rubber, and 402 is a blade holder for holding the blade 401.

The four ink jet cartridges mounted on the carriage 9 are black ink (hereinafter abbreviated as K), cyan ink (hereinafter abbreviated as C), magenta ink (hereinafter abbreviated as M), and yellow ink (hereinafter Y). Is abbreviated), and the inks are superposed in this order. The color intermediate color can be realized by appropriately overlapping the ink dots of C, M, and Y colors. That is,
It can be realized by overlapping M and Y for red, C and M for blue, and C and Y for green. Black can be realized by superimposing three colors of C, M, and Y. However, it is difficult to accurately superimpose black at this time, and it is difficult to accurately superimpose it. The implantation density of is too high. Therefore, only black is ejected separately (using black ink).

(Control Configuration) Next, a control configuration for executing recording control of each unit of the above-described apparatus configuration will be described with reference to FIG.
Will be described with reference to. In the figure, 60 is a CPU, 6
Reference numeral 1 is a program ROM for storing a control program executed by the CPU 60, and 62 is an EE for storing various data.
It is a PROM. Reference numeral 63 is a main scanning motor for conveying the recording head, and 64 is a sub scanning motor for conveying the recording paper.
It is also used for suction operation by a pump. Reference numeral 65 is a wiping solenoid, 66 is a paper feeding solenoid used for paper feed control, 67 is a cooling fan, and 68 is a paper width detection LED that is turned on during the paper width detection operation. Reference numeral 69 is a paper width sensor, 70 is a paper floating sensor, 71 is a paper feed sensor, 72 is a paper discharge sensor, and 73 is a suction pump position sensor that detects the position of the suction pump. 74 is a carriage HP sensor that detects the home position of the carriage, and 75 is a door open sensor that detects the opening and closing of the door.

Reference numeral 78 is a gate array for controlling the supply of recording data to the four color heads, 79 is a head driver for driving the heads, 8a is an ink cartridge for four colors,
8b is a recording head for four colors, and here, 8a and 8b
Is shown as a representative of black (Bk). The ink cartridge 8a has an ink remaining amount sensor 8f for detecting the remaining amount of ink. The head 8b has a main heater 8c for ejecting ink, a sub-heater 8d for controlling temperature control of the head, and a ROM 85 storing various information of the head.
Have 4.

FIG. 6 is a schematic view of a heater board (HB) 853 of the head used in this embodiment.
A temperature control (sub) heater 8d, a discharge (main) heater 8c, a discharge portion array 8g, and a drive element 8h are formed on the same substrate in the positional relationship shown in FIG.
By arranging each element on the same substrate in this manner, the head temperature can be detected and controlled efficiently, and the head can be made compact and the manufacturing process can be simplified. Further, in the figure, H.264. The positional relationship of the outer peripheral wall cross section 8f of the top plate that divides B into a region filled with ink and a region not filled with B is shown.

(Embodiment 1) Next, Embodiment 1 of the present invention in which a temperature detecting member capable of directly detecting the temperature of a recording head and a temperature calculation circuit thereof are added to the above-described recording apparatus will be described with reference to the drawings. To explain.

FIG. 6 shows a temperature detecting member of the recording head in this embodiment. In FIG. 6, the head temperature sensor 8e is arranged on the heater board 853 of the recording head together with the ejection heater 8g and the sub heater 8d, and is thermally coupled to the heat source of the recording head. In this embodiment, a temperature sensor (Di sensor) is used by using the output temperature characteristic of a diode for temperature detection, which is formed at the same time as the diode formed on the heater board as a part of the drive circuit of the discharge heater.
I am trying.

FIG. 13 shows the temperature characteristic of the temperature detecting member of the recording head of this embodiment. In this embodiment, constant current driving of 200 μA is performed, and the output voltage V _F at 25 ° C. is 57.
It shows an output characteristic of 5 ± 25 mV and a temperature dependence of approximately −2.5 mV / ° C. Although there is little variation in the temperature dependence in manufacturing the device, the output voltage may fluctuate greatly, and a variation of about 25 ° C. may occur. The temperature detection accuracy required in this embodiment is about 2 ° C., and in order to measure the correction value at the time of shipment of the recording head and to provide the recording head with information, 12
Rank identification information is required. Although it is possible to suppress variations in the temperature sensing element during the manufacturing process, it is clear that the manufacturing cost of the recording head will increase, and in the case of a recording head that is supposed to be replaced as in this embodiment, Is very disadvantageous.

Therefore, in this embodiment, calibration is performed so that the temperature sensor of the recording head is corrected by the reference sensor provided in the recording apparatus main body. By correcting the detection temperature, the temperature of the ink in the common liquid chamber surrounded by the top plate 8f, which is important for stabilizing the ejection, particularly the ink temperature of the ejection portion can be detected with high accuracy. It has become possible to achieve stabilization.

(Outline of Ejection Stabilization) In this embodiment, an example is shown in which ejection is stabilized by using the temperature detection value of the recording head. In the present embodiment, the exchangeable recording head has been described, but it goes without saying that a permanent type recording head which does not require head replacement may be used. In that case, the effects of the present invention when an abnormality occurs in the recording apparatus as described above. Needless to say, is demonstrated.

In this embodiment, the PWM discharge amount control described later based on the temperature change of the ink attempts to control the discharge amount to be constant. That is, by stabilizing the ejection amount, it is possible to eliminate the density change within one line and the density change within the page. At the same time, by optimizing the recording conditions and the recovery conditions, the deterioration of the image quality due to ejection failure or ink overflow on the recording paper is prevented.

(PWM Control) Next, the PWM discharge amount control method of this embodiment will be described in detail with reference to the drawings. FIG. 7 is a diagram for explaining the divided pulse according to the present embodiment. In the figure, VOP is the drive voltage, P1 is the pulse width of the first pulse (hereinafter referred to as pre-pulse) of the plurality of divided heat pulses, P2 is the interval time,
P3 is the pulse width of the second pulse (hereinafter referred to as the main pulse). T1, T2 and T3 are P1, P2 and P3
Shows the time to decide. The driving voltage VOP is one of the electric energy necessary for the electrothermal converter to which this voltage is applied to generate thermal energy in the ink in the ink liquid path formed by the heater board and the top plate. is there. The value depends on the area of the electrothermal converter, the resistance value, the film structure and the liquid path structure of the recording head.

The PWM ejection amount control of the present embodiment can be said to be a pre-pulse width modulation driving method. When ejecting one ink droplet, pulses are sequentially applied in the widths of P1, P2 and P3, and the width of the pre-pulse depends on the ink temperature. To modulate. The pre-pulse is a pulse mainly for controlling the ink temperature in the liquid passage, and plays an important role of the ejection amount control of the present invention. The preheat pulse width is preferably set to a value that does not cause a bubbling phenomenon in the ink due to the thermal energy generated by the electrothermal converter when it is applied.
The interval time secures a time for transmitting the energy of the prepulse to the ink in the ink liquid path. The main pulse is for causing bubbling in the ink in the liquid path and ejecting the ink from the ejection port,
The width P3 is preferably determined by the area of the electrothermal converter, the resistance value, the film structure and the structure of the ink liquid path of the recording head.

For example, the action of the pre-pulse in the recording head having the structure shown in FIGS. 8A and 8B will be described. FIGS. 1A and 1B are a schematic vertical 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, along an ink liquid path. In the figure, the electrothermal converter (discharge heater) generates heat by the application of the divided pulse. This electrothermal converter is arranged on the heater board together with electrode wiring for applying a divided pulse thereto. The heater board is made of silicon and is supported by an aluminum plate that forms the substrate of the recording head. A groove for forming an ink liquid path or the like is formed on the top plate, and the top plate and a heater board (aluminum plate) are joined together to form an ink liquid path or a common liquid chamber for supplying ink to this. Is configured. In addition, ejection ports are formed on the top plate, and ink liquid paths communicate with the respective ejection ports.

In the recording head shown in FIG. 8, the driving voltage VOP = 18.0 (V) and the main pulse width P3 =
4.114 [μsec] and prepulse width P1 is 0 to
When changing in the range of 3,000 [μsec], FIG.
The relationship between the ejection amount Vd [pl / drop] and the pre-pulse width P1 [μsec] is obtained as shown in FIG. This figure is a diagram showing the prepulse width dependence of the ejection amount. In the figure, V0 shows the ejection amount when P1 = 0 [μsec], and this value is determined by the head structure shown in FIG. Incidentally, V0 in this embodiment is V when the ambient temperature TR is 25 ° C.
It was 0 = 18.0 [pl / drop].

As shown by the curve a in FIG. 9, as the pulse width P1 of the pre-pulse increases, the ejection amount Vd linearly increases from the pulse width P1 of 0 to P1LMT, and the pulse width P1 becomes larger. In the range larger than P1LMT, the change loses the linearity and is saturated at the pulse width P1MAX and becomes maximum. In this way, the range up to the pulse width P1LMT in which the change in the ejection amount Vd with respect to the change in the pulse width P1 shows linearity is the pulse width P1.
It is effective as a range in which the discharge amount can be easily controlled by changing Incidentally, in the present embodiment shown by the curve a, P1LMT = 1.87 (μs), and the discharge amount at this time was VLMT = 24.0 [pl / drop]. Also,
The pulse width P1MAX when the discharge amount Vd becomes saturated is
P1MAX = 2.1 [μs] and the discharge amount VMA at this time
X = 25.5 [pl / drop].

When the pulse width is larger than P1MAX, the ejection amount Vd becomes smaller than VMAX. This phenomenon is such that when a pre-pulse having a pulse width in the above range is applied, minute bubbles (a state immediately before film boiling) are generated on the electrothermal converter, and the next main pulse is applied before the bubbles disappear. The minute bubbles disturb the bubbling due to the main pulse, so that the discharge amount becomes small. This area is called a pre-foaming area, and it is difficult to control the ejection amount through the pre-pulse in this area.

When the slope of the straight line showing the relationship between the discharge amount and the pulse width in the range of P1 = 0 to P1 LMT [μs] shown in FIG. 9 is defined as the prepulse dependence coefficient, the prepulse dependence coefficient: KP = ΔVdp / ΔP1 [pl / Μsec · drop]. This coefficient Kp is determined by the head structure, driving conditions, ink physical properties, etc., regardless of temperature. That is, the curves b and c in FIG. 9 show the case of other recording heads, and it can be seen that the ejection characteristics change when the recording heads are different. As described above, since the upper limit P1LMT of the pre-pulse P1 is different when the recording heads are different, the ejection amount control is performed by setting the upper limit P1LMT for each recording head as described later. Incidentally, in the case of the recording head and ink shown by the curve a in this embodiment, KP = 3.209 [pl / μsec
・ Drop].

On the other hand, another factor that determines the ejection amount of the ink jet recording head is the ink temperature of the ejection portion (the temperature of the recording head may be a substitute). Figure 10
FIG. 4 is a diagram showing the temperature dependence of the discharge amount. Curve a in the figure
As shown in, the ejection amount Vd increases linearly with the increase of the temperature TH of the recording head (in this case, it is equal to the ink temperature of the ejection portion because of the static temperature characteristic). When the slope of this straight line is defined as the temperature dependence coefficient, the temperature dependence coefficient: KT = ΔVdT / ΔTH [pl / ° C./drop]. This coefficient KT is determined by the structure of the head, the physical properties of the ink, etc., not by the driving conditions. Also in FIG. 10, curves b and c show cases of other recording heads. In the recording head of this embodiment, KT = 0.3 [pl / ° C.
drop].

The relationship shown in FIGS. 9 and 10 is shown in FIG. 11 as an actual control diagram. In the figure, T ₀ is a heat retention temperature of the recording head, and when the ink temperature of the ejection portion is lower than T ₀ , the recording head is heated by the sub heater. Therefore, the PWM control, which is the ejection amount control according to the ink temperature, is performed at a temperature of T ₀ or higher.

The temperature range shown as the PWM region in FIG. 11 is a temperature range in which the ejection amount can be stabilized, and in this embodiment, the ink temperature of the ejection portion is 34 to 54 ° C. FIG. 11 shows the relationship between the ink temperature of the ejection portion and the ejection amount when the pre-pulse is changed in 11 steps. Even if the ink temperature of the ejection portion changes, the temperature step width ΔT is changed according to the ink temperature. By changing the pulse width of the pre-pulse,
The discharge amount can be controlled within a range of ΔV with respect to the target discharge amount V _d0 .

FIG. 12A is a correspondence table of ink temperature and prepulse. In this embodiment, the replaceable IJC is used as the recording head, but if the ejection amount differs for each cartridge, the correspondence table of the ink temperature and the prepulse may be changed for each head. For example, the table of FIG. 12 (B) may be used for a cartridge having a small discharge amount, and the table of FIG. 12 (C) may be used for a large cartridge, and the pre-pulse dependence coefficient and temperature dependence coefficient of the discharge quantity may be used. You may have a table according to your needs.

(Temperature Calibration) The temperature detecting member of the recording head in the present embodiment is calibrated by using the chip thermistor 5024 provided on the main body electrical board at the time of non-recording in which the ink temperature of the ejection portion fluctuates little. I am trying. The chip thermistor 5024 is provided on the electrical board together with its detection circuit, and is calibrated before shipment of the recording device, including variations in the detection circuit.

Since the chip thermistor 5024 can detect the temperature inside the recording apparatus main body, it is considered that the temperature of the recording head and the detected value are equal to each other in a state where energy for heat retention and ejection is not applied to the recording head. Further, even when such energy is applied to the recording head, the temperature inside the recording apparatus main body and the temperature of the recording head become substantially equal after a predetermined time elapses after the energy is applied.

Therefore, in this embodiment, a non-recording time measuring timer for measuring the non-recording time is provided, and the temperature detecting member of the recording head is calibrated when the non-recording state exceeds a predetermined time. Then, a correction value for matching the actual measurement value of the temperature detection member of the recording head with the detection temperature of the chip thermistor of the main body is calculated, and the RAM or the EEPROM 6
The temperature of the recording head is calculated by adding the correction value to the actually measured value. Here, the non-recording time in this embodiment does not include the time when the recording head is kept warm as a preliminary recording operation because energy is not applied to the recording head.
Further, if the battery means can also be used as the timer means with the battery backed up, the power off time may be measured in order to simplify the control of the timer.

Further, as the calibration execution time, the calibration may be performed every time when the non-recording time becomes a predetermined time or more, but when the non-recording time becomes a predetermined time or more, the calibration request signal is sent. It may be performed only after it has been generated, but not at that point, but before the next recording is started or immediately after the power is turned on, before the new energy is applied to the recording head.

As a heat source inside the printing apparatus, a power source section of the printing apparatus and a control element itself on an electrical board may be mentioned as a heat source, and in some cases, a reference temperature sensor of the main body. The temperature detected by the chip thermistor 5024 may be higher than the temperature of other places in the printing apparatus including the print head. Therefore, in this embodiment, the temperature detected by the chip thermistor 5024 is set to the power supply of the recording device.
I am trying to make corrections based on time. Table 1 is a correction table for that purpose, and the power-on time is measured by using the same timer as that for measuring the non-recording time.

[0049]

[Table 1] In the present embodiment, the power-on time timer measures a simple elapsed time from when the power is turned on until the time when the temperature sensor of the printhead is corrected. However, the heat generation amount of the power supply and the drive of the printhead are measured. When the amount of heat generated by the circuit has a great influence, the temperature rise amount calculated based on the energy input to the recording head in addition to the power-on time may be corrected. Further, the correction may be performed based on all the past power-on times that affect the local temperature rise of the chip thermistor 5024 of the main body and the energy input to the recording head.

FIG. 14 is a processing flow for calibrating the temperature detecting member of the recording head in this embodiment, and the calibration processing will be specifically described with reference to the block diagram of FIG.

First, when the power is turned on in step S100, the CPU 60 reads the Di sensor correction value (a) stored in the EEPROM 62 into the RAM in the CPU 60, and the Di sensor can be used for correction (S11).
0). Next, the power on timer is reset / started to prepare for temperature rise correction of the chip thermistor 5024 of the main body (S120). Next, the non-recording time timer for determining the timing of Di sensor correction is reset / started (S140). In this state, the non-recording time timer is u
p (S150) or print signal is input (S1)
It stands by while judging 60).

When the print signal is input first, the head heat retention is started in preparation for printing (S170). in this case,
For temperature detection to keep warm, EE the Di sensor of the recording head
The correction is carried out with the correction value stored in the PROM 62. A recording operation (printing) is performed following the heat retention (S
180), the head heat retention is stopped (S190). During printing, as described above, the ejection can be stabilized by the PWM ejection amount control method based on the detected temperature of the recording head. Further, since energy is applied to the recording head in the above-described head heat retention and recording operation, the temperature of the recording head is generally high unlike the temperature of the chip thermistor 5024 on the main body electrical component substrate. Therefore, after recording is completed, the non-recording time timer is reset / started (S
140) and waits for the correction timing of the Di sensor.

When the non-recording time timer is up during standby, that is, when it is considered that the temperature inside the recording apparatus main body (the temperature of the chip thermistor 5024) and the temperature of the recording head have become almost equal, the Di sensor Make a correction. In this embodiment, the non-recording time timer is set to be up after 30 minutes have passed. To correct the Di sensor, first, the temperature (Td) of the reference thermistor (chip thermistor 5024) is read (S200), and the data of the power-on timer for temperature rise correction is referenced (S210) to raise the reference thermistor temperature. Perform temperature correction. The temperature rise correction is performed using the correction value b in the table of Table 1 stored in the program ROM 61 (Tt + b).

Next, the Di sensor temperature (Td) is read (S230), and the correction value (a) of the Di sensor is calculated (S240). The correction value of the Di sensor is obtained as a difference (Tt + b-Td) between the temperature (Tt + b) of the reference thermistor 5024 after the temperature rise correction and the Di sensor temperature (Td). The correction value (a) of the Di sensor which is the temperature sensor of the recording head obtained as described above is used as the backup EE.
CPU to store in PROM and use for the next temperature control
It is left in the RAM in 60 (S250). Since the correction of the Di sensor is completed, the process returns to S140 in preparation for the next correction timing or printing.

Since the temperature detecting member of the recording head can be easily calibrated as described above, even if the recording head of the present embodiment can be replaced, the temperature control of the recording head can be stably performed. . Also, by controlling using the temperature detection member of the recording head that is simply calibrated as described above,
The actual ejection amount can be controlled stably regardless of the ink temperature,
It is possible to obtain a high-quality recorded image with uniform density.

In this embodiment, the correction is made after 30 minutes of non-recording time, but the required calibration (correction)
It may be set appropriately according to the accuracy of.

In this embodiment, the double-pulse PWM for controlling the ejection amount is used as an example of calibrating and using the temperature detecting member of the recording head. However, even if the single-pulse PWM is used, the triple pulse is used. PW of the above pulse
You may use M. Further, in the present embodiment, an example is shown in which control is performed so as to perform optimum ejection according to the temperature of the print head. However, for example, the print speed may be changed so that the temperature of the print head falls within a predetermined range. It may be used for control such as postponing (standby) recording. Further, not only the drive control of the print head, but also a known recovery system as a discharge stabilization means, for example, detection of a temperature detection member calibrated for control of ink forced discharge means from the print head, wiping means and preliminary discharge means It is also possible to use temperature.

(Embodiment 2) This embodiment shows an example in which the calibration timing of the temperature detecting member (Di sensor) of the recording head is determined by measuring the temperature change rate detected by the temperature detecting member. The present invention is not limited to the structure of the recording head or the structure of the temperature detecting member itself of the recording head, and therefore, the same as those in the above-described first embodiment, focusing on the calibration timing determination method, and referring to FIG. explain. In addition,
15, the same steps as those in FIG. 14 are designated by the same reference numerals.

In this embodiment, D is set immediately after the power is turned on.
The rate of change in the temperature detected by the i sensor is measured (S300).
The rate of change of the detected temperature is measured by calculating the temperature deviation for each predetermined time. In this embodiment, the detected temperature is read every one minute, and the R in the CPU 60 is read.
Stored in the AM, the difference between the current detected temperature and the detected temperature one minute before is calculated as the detected temperature change rate (α). Step S
At 310, when the rate of change is less than 0.2 deg / min, that is, when it is considered that the temperature inside the recording apparatus main body (the temperature of the chip thermistor 5024) and the temperature of the recording head are almost equal, The Di sensor is calibrated (S310). However, in this embodiment, in order to avoid frequent calibration, it is determined whether or not the correction is performed so that the correction is performed only once for each power-on (S32).
0). In the case of the first time, the calibration is performed in the same manner as the above-mentioned embodiment, and the calibration completion is recorded at the end (S33).
0).

In the present embodiment, since the sensor correction need only be performed once when the head is replaced, the power source o
I think it is enough to do it at least once after n.
Therefore, the power supply on for a relatively long time shown in the above embodiment is turned on.
The temperature rise correction of the main body reference temperature sensor, which is a later temperature correction method, may be omitted. In this embodiment, since it is considered that the recording head is calibrated relatively early after the power is turned on, if the power on / off is not frequent, even if there is no rewritable memory element such as the EEPROM 62, the power is turned on after the power is turned on. The printing of several sheets may be performed using the average value of temperature correction stored in the ROM in advance.

If the replacement of the recording head can be detected in some way, such as the mechanical SW detecting the attachment / detachment of the recording head, the rate of change is smaller than a predetermined value after the replacement signal of the recording head is input. In that case, the calibration may be performed only once.

In this embodiment, the rate of change is 0.2 deg.
If it is less than / min, the Di sensor of the recording head is calibrated. However, the reference rate of change can be set according to the required accuracy of calibration (correction).

(Embodiment 3) In this embodiment, an example of a method for preventing erroneous correction of the temperature detecting member of the recording head will be described. There is a case where a normal temperature cannot be detected due to a failure such as a disconnection of the temperature detecting member of the recording head or an abnormality of the detection circuit of the main body. In particular, in the case of a replaceable head, the electrical connection of the temperature detecting member may be temporarily defective. In addition, the electrostatic noise may cause a temporary abnormality of the detection circuit.

Therefore, in this embodiment, when a temporary abnormality occurs as shown in FIG. 16, the calibration of the temperature detecting member is postponed or stopped. In FIG. 16, the same steps as those in FIG. 15 are designated by the same reference numerals.

When the correction value is 10 or more as shown in step S340 in FIG. 16, it is determined that the above-mentioned above has occurred and the correction value is not stored / updated. If the correction value is less than 10, the correction value is updated (S25).
0). In this embodiment, when a correction value abnormality occurs, the next correction timing is waited for, but a warning may be displayed to the user as a temperature abnormality and the recording head may be reattached.

The present invention brings excellent effects particularly in a recording head and a recording apparatus of a system utilizing thermal energy among the ink jet recording systems.

With regard to its typical structure and principle, see, for example, US Pat. Nos. 4,723,129 and 4740.
What is done using the basic principles disclosed in 796 is preferred. This method can be applied to both the so-called on-demand type and continuous type, but especially in the case of the on-demand type, liquid (ink)
By applying at least one drive signal to the electrothermal converter arranged corresponding to the sheet or liquid path in which the is held, which corresponds to the recorded information and gives a rapid temperature rise exceeding nucleate boiling, This is effective because heat energy is generated in the electrothermal converter to cause film boiling on the heat acting surface of the recording head, and as a result, bubbles can be formed in the liquid (ink) in one-to-one correspondence with this drive signal. The liquid (ink) is ejected through the ejection openings by the growth and contraction of the bubbles to form at least one droplet. It is more preferable to make the driving signal into a pulse shape because bubbles can be grown and contracted immediately and appropriately, and thus a liquid (ink) with excellent responsiveness can be ejected. This pulse-shaped drive signal is disclosed in U.S. Pat. No. 4,463,359 and No. 43.
Those as described in 45262 are suitable. If the conditions described in US Pat. No. 4,313,124, which is an invention relating to the rate of temperature rise on the heat acting surface, are adopted, more excellent recording can be performed.

As the constitution of the recording head, in addition to the combination constitution of the ejection port, the liquid passage, and the electrothermal converter (the linear liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned specifications, US Pat. No. 4,558,333, US Pat. No. 4,558,333, which discloses a configuration in which a heat acting portion is arranged in a bending region.
A configuration using the specification of No. 459600 is also included in the present invention. In addition, Japanese Laid-Open Patent Publication No. 123670/1984 discloses a configuration in which a common slit is used as a discharge portion of the electrothermal converter for a plurality of electrothermal converters, and an opening for absorbing a pressure wave of thermal energy. The present invention is also effective as a configuration based on Japanese Patent Laid-Open No. 138461/1984, which discloses a configuration that corresponds to the discharge portion.

[0069]

As described above, according to the present invention, the temperature detecting member provided in the recording head is simply calibrated by the reference temperature sensor provided in the main body, which is important for stabilizing the ejection. It is possible to detect the temperature of the recording head with high accuracy and obtain a high-quality image.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of a suitable inkjet recording apparatus to which the present invention is applied or applied.

FIG. 2 is a perspective view showing a replaceable cartridge.

FIG. 3 is a cross-sectional view of a recording head.

FIG. 4 is a schematic perspective view of a recovery system unit.

FIG. 5 is a block diagram showing a control configuration for executing a recording control flow.

FIG. 6 is a diagram showing a positional relationship among a sub heater, a discharge (main) heater, and a temperature sensor of a head used in this embodiment.

FIG. 7 is an explanatory diagram of drive pulses of a recording head involved in temperature stabilization control of ejection.

8A and 8B are a schematic vertical 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, along an ink liquid path.

FIG. 9 is a diagram showing pre-pulse dependency of ejection amount.

FIG. 10 is a diagram showing the temperature dependence of the discharge amount.

FIG. 11 is an explanatory diagram related to discharge amount control.

FIG. 12 is an ink temperature and pre-pulse conversion table for controlling the ejection amount.

FIG. 13 is a diagram showing the output characteristic of the temperature sensor of the recording head used in this embodiment.

FIG. 14 is a flowchart showing calibration of the temperature detection member of the recording head in the first embodiment.

FIG. 15 is a flowchart showing calibration of the temperature detecting member of the recording head in the second embodiment.

FIG. 16 is a flowchart showing calibration of the temperature detecting member of the recording head in the third embodiment.

[Explanation of symbols]

8b recording head 8c Discharge (main) heater 8d sub heater 8e Temperature sensor 9 carriage 60 CPU 78 gate array 78b print buffer 78c line duty buffer 108 outlet 5012 recording head 5013 Discharge (main) heater 5014 Sub heater 5025 Chip thermistor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical indication location 9012-2C B41J 3/04 104 K (72) Inventor Kiichiro Takahashi 3-30 Shimomaruko, Ota-ku, Tokyo No. 2 Canon Inc.

Claims (6)

[Claims] 1. A head temperature detecting member provided on a recording head for ejecting ink, a reference temperature detecting member provided on a main body, and the head temperature based on the reference temperature detected by the reference temperature detecting member. An inkjet recording apparatus comprising: a calibration unit that calibrates a head temperature detected by a detection member at a predetermined timing. 2. The calibration means has a timer means for timing the non-recording period, and based on the reference temperature detected by the reference temperature detection member when the non-recording period has passed a predetermined time or more. The ink jet recording apparatus according to claim 1, wherein the head temperature detected by the head temperature detecting member is calibrated. 3. The calibration means includes temperature change rate measuring means for measuring a reference temperature change rate of the temperature detecting member within a predetermined time, and when the temperature change rate is smaller than a predetermined value, The ink jet recording apparatus according to claim 1, wherein the head temperature detected by the head temperature detection member is calibrated based on the reference temperature detected by the reference temperature detection member. 4. The calibration means has a replacement detection means for detecting replacement of the recording head, and based on the reference temperature detected by the reference temperature detection member when the replacement of the recording head is detected. The ink jet recording apparatus according to claim 1, wherein the head temperature detected by the head temperature detecting member is calibrated. 5. The temperature correction amount, wherein the calibration means calculates a difference between a head temperature detected by the temperature detection member before calibration and a reference temperature detected by the reference temperature detection member to obtain a temperature correction amount. 5. The ink jet recording apparatus according to claim 1, further comprising a calculating means, and a calibration abnormality detecting means for stopping the calibration when the temperature correction amount is equal to or higher than a predetermined temperature. 6. The ink jet recording apparatus according to claim 1, wherein the recording head causes a state change in the ink by thermal energy and ejects the ink based on the state change. .