JP3466732B2 - Ink jet recording device - Google Patents

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 ink by ejecting ink onto a recording material, and more particularly to a detection method for optically detecting the width of the recording material in the main scanning direction by a recording head. The present invention relates to an inkjet recording device having a unit.

[0002]

2. Description of the Related Art FIG. 4 shows a configuration example of a conventional ink jet recording apparatus. Here, 1 is an inkjet recording apparatus with an outer case (not shown) removed, and 100 is a host apparatus for transmitting recording data to the recording head unit 2 of the inkjet recording apparatus 1. The printhead unit 2 of this example has printheads 2Bk, 2C, 2M, and 2Y that eject black ink (Bk), cyan ink (C), magenta ink (M), and yellow ink (Y), respectively.
The recording heads 2Bk, 2C,
2M and 2Y are mounted on the carriage 3 in parallel.
4Bk, 4C, 4M and 4Y are ink tanks that are detachably held on the main body side of the recording apparatus 1 and supply respective color inks to the recording heads 2Bk, 2C, 2M and 2Y via an ink supply pipe (not shown). is there.

Reference numeral 5 is a guide shaft for guiding the movement of the carriage 3, 6 is a timing belt connected to the carriage 3 for moving the carriage 3, 7 is a motor for driving the timing belt 6 (hereinafter referred to as main scanning motor), 8 Is a platen that holds a recording sheet S that is a recording material. It should be noted that each of the recording heads 2B is reciprocally moved in the direction A of the carriage 3 with respect to the recording sheet S held on the platen 8.
Ink droplets of the respective colors are ejected from k, 2C, 2M, and 2Y, and each time one line of recording is performed, the conveyance rollers 9 and 10 that support the recording sheet S so that the recording sheet S can be conveyed in the direction of arrow B (sub-direction Sheet feed in the scanning direction)
By repeating the recording operation for one line and the sheet feeding for one line as described above, a color image is recorded on the recording sheet S. The sub-scanning motor that drives the transport rollers 9 and 10 is not shown.

Reference numeral 11 denotes an outer case (not shown) of the recording apparatus 1.
Reference numeral 12 is an operation panel 1 fixed on the upper side.
The LCD display plate on 1 and 13 are a group of operation keys. In the case of this example, the operation key group 13 includes an online / offline switching key 13A, a line feed key 13B, a form feed key 13C, a recording mode switching key 13D and the like. Reference numeral 14A is an online / offline display LED, and 14B is an alarm display LED. Reference numeral 15 is a power supply device that supplies power of various voltages to the inkjet recording apparatus 1 itself. The carriage 3 is provided with a sheet width detection sensor 201 for detecting the width of the recording sheet S in the main scanning direction. The detection operation detected by the sheet width detection sensor 201 will be described later. Detailed description. In addition, although not shown, when the carriage 3 is guided to the outside of the recording area, a cap member that covers the ink ejection surfaces of the recording heads 2Bk to 2Y, a wiper that wipes the ink ejection surface, and a cap member, Drive means are provided for operating the wiper.

FIG. 5 shows a basic structure of each of the recording heads 2Bk, 2C, 2M and 2Y incorporated in the recording head unit 2. Here, 21 is a common liquid chamber to which each color ink is supplied from each of the ink tanks 4Bk to 4Y shown in FIG. 4, 22 is a liquid channel through which the ink is guided from the common liquid chamber 21, and 23 is an individual liquid channel. An electrothermal converter (hereinafter, referred to as a heater), which is disposed in the reference numeral 24, is an ink ejection port for ejecting an ink droplet toward the recording sheet S. A common electrode 24A that supplies a common heating voltage VH and an individual drive electrode 24B are connected to each heater 23.
Reference numeral 25 is a heat driver provided for each individual drive electrode 24B, 26 is an AND gate for outputting a drive signal to the base of the heat driver 25 by a signal from a heat signal generation circuit 27 and a recording data serial / parallel conversion circuit 28, 29 Is a recording head control circuit that controls the outputs to the data conversion circuit 28 and the heat signal generation circuit 27 based on the recording data.

The recording heads 2Bk to
In 2Y, the print data signal output from the print head control circuit 29 is supplied to the AND gate 26 via the print data conversion circuit 28, and the heat signal is supplied to the AND gate 26 via the heat signal generation circuit 27. Thus, the heater 24 selectively driven by the heat driver 25 driven by both signals causes the ink 30 in the corresponding liquid passage 24 to generate bubbles 31 due to film boiling. Then, due to the pressure change caused by the bubble 31, the ink is ejected from the ink ejection port 24 as a flying ink drop 30A, and the landing on the recording sheet S forms a dot pattern for recording. In addition, after that, the heater 23 is cooled by turning off the power supply through the heat driver 25, and the liquid passage 22 is cooled as the bubbles 31 disappear.
The ink 30 is newly replenished.

Next, the structure of the sheet width detecting sensor 201 and its detecting operation will be described with reference to FIG.

FIG. 6A shows an example of the structure of the sheet width detecting sensor 201. The sensor 201 is composed of a photocoupler including a light emitting portion 201A and a light receiving portion 201B, and a photodiode 201A which is a light emitting portion. Light such as infrared rays emitted from the platen 8 or the recording sheet S is reflected by the light receiving portion (phototransistor) 201B.
Incident on. The collector of the phototransistor 201B is connected to a 5V power source in this example via a resistor R1. Therefore, since the amount of reflected light changes between the surface of the platen 8 finished in gray or the like and the surface of the white recording sheet S, the output of the change is changed to the A / D conversion circuit 202.
Is input to the CPU 203, quantized and supplied to the CPU 203, and the width of the recording sheet S is determined by the CPU 203.

FIGS. 6A and 6B show the detection operation by the sheet width detection sensor 201. Now, as shown in (B), when the recording sheet S is not held at the main scanning position on the platen 8, when the carriage 3 performs main scanning in the A1 direction indicated by the broken line, the sheet width detection sensor 201
Sends a V _p level signal as a detection output of the platen 8 to the CP
Supply to U203. Here, V _th represents a threshold value as a recording sheet detection level. Further, (C) shows a state in which the recording sheet S is held at the main scanning position on the platen 8. In such a state, when the carriage 3 performs main scanning in the A2 direction indicated by the broken line, the sheet width detection sensor 20
In No. 1, in the area on the platen 8 where the recording sheet S is present with the V _p level as the platen detection output, the detection output V lower than the recording sheet detection level (threshold) V _Th
The signal _s is supplied to the CPU 203. Therefore, the sheet width of the recording sheet S can be detected from the time between the fall and rise of the signal V _s output.

A routine for detecting the recording sheet width based on the detection output of the sheet width detecting sensor 201 will be described below.

When the sheet width detection routine is entered, the CPU 2
In 03, first, the carriage 3 located at the left end is moved to the platen level detection position. After that, the detection level sheet width detection sensor 201 of the platen 8 reads it. At this time, it is necessary to confirm that the reflection level is above a certain level. This is because if the trailing edge of the sheet S on the platen 8 remains at the time of the previous discharge, the sheet width cannot be detected correctly, and this is detected. Thus, when the appropriate detection level (V _p ) of the platen 8 is read, a level smaller by a certain constant value (A) is calculated from this value, and this is held as the threshold level V _th . And after this, the carriage 3
6 is moved to the right end as shown in FIG. 6B, and the sheet feeding operation is performed.

After the sheet feeding operation is performed, the value of the sensor 201 is read while further moving the carriage 8 from the right end to the left. Then, the area where a value smaller than V _th is obtained at this time is recognized as the width of the recording sheet S. Further, when the carriage 8 has completed moving to the left end as shown in FIG. 6C, but there is no recording sheet S existing area (V _s area) lower than the threshold value V _th , If the delivery fails, enter the error routine.

[0013]

However, in the ink jet recording apparatus 1, ink is recorded on the recording heads 2Bk to 2Bk.
The recording is performed by ejecting from Y, but when the recording is performed densely on the recording sheet S such as thin paper, the components such as water in the ink penetrate the recording sheet S, and as shown in FIG. Dirt 300 may adhere to the platen 8. As a result, the amount of light reflected from the platen 8 decreases and the platen 8
Detection level V _p becomes large. As a result, even when the recording sheet S does not exist, the threshold value V
There is a possibility that the sheet width of the recording sheet S may be erroneously detected by detecting the value V _pc smaller than _th .

An object of the present invention is to provide a recording apparatus capable of performing accurate recording by controlling so as to check the reflection level from the platen 8 in order to deal with the above-mentioned problems.

[0015]

In order to achieve the above object, the present invention records an image on a recording material positioned on a platen by using a recording head capable of ejecting ink, and follows the platen. In order to detect the width of the recording material on the platen using the light amount detection means that moves in the width direction of the recording material, based on the detection level of the amount of reflected light from a predetermined position on the platen, An inkjet recording apparatus that sets a threshold value that serves as a criterion for determining whether or not the amount of reflected light is from the recording material, in order to detect the width of the recording material on the platen, A moving mechanism for moving the light amount detecting means to a position for detecting the reflected light amount from the predetermined position, and then moving the light amount detecting means in the width direction of the recording material along the platen; A memory amount detecting means for storing the detected level of the reflected light amount from the predetermined position detected earlier,
The detection level of the reflected light amount from the predetermined position detected this time by the light amount detection means is compared with the previous detection level stored in the memory, and when the difference between them is within a predetermined set value, the current Means for setting the threshold value based on the detection level and not setting the threshold value based on the current detection level when the difference between them is not within the set value. .

[0016]

According to the present invention, the change of the reflected light amount from the platen and the recording material held on the platen is detected by the light amount detecting means during the movement scanning along the platen by the recording head, and the change of the reflected light amount is detected. It is possible to detect the width of the recording material in the moving scanning direction based on it, and to detect the stain of the ink adhering to the platen from the platen in which the recording material is not held by the light amount detection means,
It is possible to prevent the above-described width of the recording material and the presence or absence of the recording material from being erroneously detected by the light amount detection means due to the contamination of the ink on the platen.

[0017]

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

FIG. 1 shows an example of a circuit configuration of a control system according to the present invention.

In FIG. 1, a CPU 203 in the form of a microprocessor is connected to a host device 100 via an interface 204, and has a program memory 205 in the form of a ROM and a data memory 20 in the form of an EEPROM.
The recording operation is controlled on the basis of a program and recording command data stored in 6 and the like, and a command signal (command) and a recording information signal read from the host device 100 into the working memory 207 in the RAM form. Furthermore, CPU2
Reference numeral 03 denotes a transport mechanism by driving the carriage motor 7 via the output port 208 and the carriage motor control circuit 209 to move the carriage 3 or driving the sheet feed motor 211 via the sheet feed motor control circuit 210. 212 is operated. Further, the CPU 203 can record a desired image on the recording sheet S by driving the recording heads 2Bk to 2Y via the head control circuit 29 based on the recording information stored in the working memory 207.

The operation panel 11 is provided for setting the operating state of the recording apparatus 1 or displaying the operating state of the recording apparatus 1. A signal from each operation key group 13 on the operation panel 11 is C through the input port 213.
It is transmitted to the PU 203. Further, control signals are sent to the LEDs 14A and 14B for displaying the operation status of the recording apparatus 1 and the LCD 12 via the output port 214.

Further, from the power supply circuit 15, a logic drive voltage Vcc (for example, 5) for operating the control logic circuit.
V), various motor drive voltage Vm (e.g. 30 V), a heat voltage V _h for energizing and heating the electrothermal transducers 23 of the recording head 2Bk~2Y, Vcc (for example, 25V) or the like is outputted.

FIG. 2 shows the control procedure of the sheet width detection operation according to the present invention. When the sheet width detection routine is first entered, the main scanning motor 7 is driven via the carriage motor control circuit 209 in step S1, and FIG. The carriage 3 is moved from the left end to the right as shown in FIG. Next, in step S2, it is determined whether or not the sheet width detection sensor 201 of the carriage 3 has reached the platen level detection point (see FIG. 7), and after waiting for that, the process proceeds to step S3. Then, the reflection level V _p is read here. The operation of the steps up to here is the same as the conventional one.

In the present embodiment, the reflection level V _p from the platen 3 read in accordance with the above-mentioned operation in the next step S4 is read during the preceding sheet width detection operation, and the reflection level V _p stored in the memory 207 is read. _It is compared with _p and it is determined in step S5 whether or not the difference is within a preset value (a limit value at which there is no risk of erroneous detection of the recording sheet S). Here, first, the memory 207
The V _p stored in the HDD may be stored at the time of factory shipment or may be read in the initial operation when the power of the recording apparatus is turned on. Then, if there is no risk of erroneous detection, that is, if it is within the range of the above set value, the process proceeds to step S6, and the V _p read this time is stored in the memory 207. If the difference exceeds the set value in step S5, the process proceeds to step S30, where L
The user is notified of the abnormality by the ED 14A, 14B, the LCD 12, the buzzer or the like, and the error processing is performed in step S31.

The error processing referred to herein means, for example, that the user wipes the platen 8 from dirt and then operates the operation keys 13 on the operation panel 11 according to the set rules. It is a series of processings such as discharging the recording sheet S held at and re-feeding the new recording sheet. The point is that the recording sheet S is newly fed after the platen 8 is wiped. Good.

[0025] Then, the memory in step S7, similarly to the conventionally V _p of the reflected level currently read, a value of A (in FIG. 6 (B), (C) see) as live value V _th to a value obtained by subtracting the 207, and in FIG.
(B), the carriage 3 is moved to the right end, and then the feeding of the recording sheet S is started in step S9.
Then, in order to enter the sheet width detection operation in the following steps, the carriage 3 is moved from the right end to the left end in step S10 as shown in FIG. 6C. During the movement, V _s based on the reflection level from the recording sheet S is read from the sheet width detection sensor 201 in step S11. Therefore, the reflection level detected during the movement in step S12 is lower than the threshold level V _th described above. It is determined whether or not it is low, and in step S13, the time when it becomes low is recognized as the right end of the recording sheet S, and this is stored in the memory 207. Further, in order to detect the case where the sheet S is not set at a fixed position on the platen due to a sheet feeding error, steps S40, S
In addition, the routine of step 41 is performed in steps S42 and S to detect the case where the sheet is obliquely fed.
43 routines are provided.

Next, in step S14, the carriage 3 is further moved to the left, the reflection level V _S is read again in step S15, and it is determined in step S16 whether the reflection level V _S is _{equal to} or higher than the threshold level V _th. To judge.
Then, the time when it becomes V _th or more is recognized as the left end of the recording sheet S in step S17, and this is stored in the memory 207. Then, in step S18, it is determined whether or not the carriage 3 has reached the left end by a detection signal from a home position sensor or the like.
The recording sheet S read out from the memory 207 in 9
The recording sheet width is calculated from the positions of the right edge and the left edge of, and the sheet width detection routine is ended. If the left end is not reached in step S18, it is determined that there is an abnormality in the moving mechanism in the main scanning direction, the process branches to step S22 and is treated as an error, and the sheet width detection routine is performed again.

FIG. 3 shows another control procedure of the sheet width detecting operation according to the present invention.

Since the basic operation from step S1 to step S19 in the control procedure according to this example is the same as that shown in FIG. 2, its explanation is omitted. However,
In the example shown in FIG. 2, the reflection level V _p from the platen 8 is compared with the previous level in steps S4 to S5, and if the difference exceeds the allowable range, the process branches to steps S30 to S31 to perform error processing. Was doing. On the other hand, FIG.
In the control procedure shown in FIG. 5, V _th as a threshold value corresponding to the previously read V _p is stored each time, and in the case of negative determination in step S5, step S30 is performed. branches to, wherein, the point of using this V _th at step S7 reads the V _th of the above is different. Therefore, according to the procedure of this example, the recording operation can be continued without the user performing extra work such as error processing.

However, the procedure shown in FIG. 2 is selected or the procedure shown in FIG.
It is also possible to let the user specify the mode, etc., by selecting the procedure shown in FIG.

In the embodiment described above, the width of the recording material in the moving and scanning direction is detected by the optical sheet width detecting sensor mounted on the carriage. However, the present invention is such a sheet width detecting sensor. It is not limited to the inkjet recording apparatus having, as long as it has a means for detecting a change in the amount of reflected light from the platen and the recording material by the optical detection means during the moving scanning related to the recording of the recording head, For example, the presence or absence of the recording material on the platen may be simply detected by this.

It should be noted that the present invention includes means (for example, an electrothermal converter or a laser beam) for generating heat energy as energy used for ejecting ink, particularly in the ink jet recording system, and the heat treatment is performed. The effect is excellent in a recording head and a recording apparatus of a system that causes a change in ink state by energy. This is because such a system can achieve high density recording and high definition recording.

Regarding the typical structure and principle thereof, see, for example, US Pat. No. 4,723,129 and US Pat. No. 4,740.
What is done using the basic principles disclosed in 796 is preferred. This method is a so-called on-demand type,
It can be applied to any of the continuous type, but especially in the case of the on-demand type, it can be applied to the sheet holding the liquid (ink) or the electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal corresponding to the recording information and giving a rapid temperature rise exceeding nucleate boiling, heat energy is generated in the electrothermal converter, and film boiling is caused on the heat acting surface of the recording head. Liquid (ink) corresponding to this drive signal in a one-to-one correspondence
It is effective because bubbles can be formed inside. Due to the growth and contraction of the bubbles, the liquid (ink) is ejected through the ejection opening to form at least one droplet. It is more preferable to make this drive signal into a pulse shape, because the bubble growth and contraction are immediately and appropriately performed, so that the ejection of the liquid (ink) with excellent responsiveness can be achieved. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. If the conditions described in US Pat. No. 4,313,124 of the invention relating to the rate of temperature rise on the heat acting surface are adopted, more excellent recording can be performed.

As the constitution of the recording head, in addition to the combination constitution of the discharge port, the liquid passage, and the electrothermal converter (the linear liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned respective 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.
The structure using the specification of No. 59600 is also included in the present invention. In addition, Japanese Unexamined Patent Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of the electrothermal converter for a plurality of electrothermal converters, and an opening for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration corresponding to the ejection portion is disclosed in JP-A-59-138461. That is, according to the present invention, recording can be surely and efficiently performed regardless of the form of the recording head.

In addition, even in the case of the serial type as in the above example, the recording head fixed to the main body of the apparatus or the electrical connection to the main body of the apparatus or the ink from the main body of the apparatus by being mounted on the main body of the apparatus. The present invention is also effective when a replaceable chip-type recording head that can be supplied or a cartridge-type recording head in which an ink tank is integrally provided in the recording head itself is used.

Further, as the constitution of the recording apparatus of the present invention, it is preferable to add ejection recovery means of the recording head, preliminary auxiliary means and the like because the effects of the present invention can be further stabilized. Specifically, heating is performed by using a capping unit, a cleaning unit, a pressure or suction unit for the recording head, an electrothermal converter or a heating element other than this, or a combination thereof. Examples thereof include a preliminary heating unit for performing the discharge and a preliminary discharge unit for performing discharge different from the recording.

Regarding the type and number of recording heads to be mounted, for example, only one is provided corresponding to a single color ink, and a plurality of inks having different recording colors and densities are supported. A plurality of pieces may be provided. That is, for example, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, but it may be either the recording head is integrally formed or a plurality of combinations may be used. The present invention is also extremely effective for an apparatus provided with at least one of full-color recording modes by color mixing.

In addition, in the above-described embodiments of the present invention, the ink is described as a liquid, but an ink that solidifies at room temperature or lower and that softens or liquefies at room temperature may be used. Or, in the inkjet system, it is common to control the temperature of the ink itself within the range of 30 ° C. or higher and 70 ° C. or lower to control the temperature so that the viscosity of the ink is within the stable ejection range. Sometimes, a liquid ink may be used. In addition, the temperature rise due to thermal energy is positively prevented by using it as the energy of the state change of the ink from the solid state to the liquid state, or in order to prevent the evaporation of the ink, it is solidified and heated in the standing state. You may use the ink liquefied by. In any case, by applying thermal energy such as ink that is liquefied by applying thermal energy according to the recording signal and liquid ink is ejected, or that begins to solidify when it reaches the recording medium. The present invention can be applied to the case where an ink having a property of being liquefied for the first time is used. In this case, the ink is
JP-A-54-56847 or JP-A-60-7
As described in Japanese Patent No. 1260, it may be configured to face the electrothermal converter in a state of being held as a liquid or a solid in the concave portion or the through hole of the porous sheet. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, as the form of the ink jet recording apparatus of the present invention, besides the one used as an image output terminal of information processing equipment such as a computer, a copying apparatus combined with a reader or the like, and further a facsimile apparatus having a transmission / reception function. It may be a form or the like.

[0039]

As described above, according to the present invention, recording is performed by ejecting ink toward the recording material by the recording head which moves and scans along the platen which holds the recording material at the recording position. In addition to the above, a light amount detection unit that detects a change in the amount of light reflected from the platen and the recording material during the moving scan and a control unit that controls the light amount detection unit to detect dirt on the platen are provided. Since it is provided, the width of the recording material in the main scanning direction can always be accurately detected even if the platen that holds the recording material at the recording position is soiled, and the reliability of the recording operation related to the width detection. You can improve your sex.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a control circuit according to the present invention.

FIG. 2 is a flowchart showing a procedure of a width detection operation in a main scanning direction of a recording material according to the present invention.

FIG. 3 is a flowchart showing another procedure of the width detection operation in the main scanning direction of the recording material according to the present invention.

FIG. 4 is a perspective view showing a configuration example of an inkjet recording apparatus to which the present invention can be applied.

FIG. 5 is a block diagram schematically showing a circuit configuration of an inkjet recording head to which the present invention can be applied.

FIG. 6 is an explanatory view showing an operation relating to width detection of a recording material in a main scanning direction, with a configuration diagram of a sheet width detection sensor (A), output level change diagrams (B) and (C) at the time of sheet width detection. It is a figure.

FIG. 7 is an explanatory diagram of a problem that occurs when detecting a sheet width in a main scanning direction of a recording material.

[Explanation of symbols]

1 Inkjet recording device 2 Recording head unit 2Bk, 2C, 2M, 2Y recording head 3 carriage 4Bk, 4C, 4M, 4Y ink tanks 7 Main scanning motor 8 Platen 11 Operation panel 13 Operation keys 15 power supply 23 Electrothermal converter 29 recording head control circuit 30 inks 100 host device 201 Sheet width detection sensor 201A light emitting unit 201B Light receiving part 203 CPU 209 Carriage motor control circuit 210 Sheet feed motor control circuit

─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Takayuki Murata 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Masahiko Umezawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-6-122259 (JP, A) JP-A-3-163951 (JP, A) JP-A-53-137629 (JP, A) JP-A-4-197947 (JP, A) A) Actual Kaihei 6-27521 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B41J 11/42

Claims (7)

(57) [Claims] 1. A light amount detecting means for recording an image on a recording material positioned on a platen by using a recording head capable of ejecting ink and for moving the recording material along the platen in the width direction of the recording material. In order to detect the width of the recording material on the platen, whether the amount of reflected light is from the recording material is determined based on the detection level of the amount of reflected light from a predetermined position on the platen. An inkjet recording device that sets a threshold value that serves as a determination reference, in order to detect the width of the recording material on the platen, the light amount detection means is set to a position for detecting the amount of reflected light from the predetermined position. A moving mechanism for moving the light amount detecting means in the width direction of the recording material along the platen after moving, and an amount of light reflected from the predetermined position previously detected by the light amount detecting means. A memory for storing the detection level, the detection level of the reflected light amount from the predetermined position detected by the light amount detection means this time, and the previous detection level stored in the memory are compared, and the difference between them is set to a predetermined value. When the value is within the value, the threshold value is set based on the current detection level, and when the difference is not within the set value, the threshold value based on the current detection level is not set. An inkjet recording device comprising: 2. The ink jet recording apparatus according to claim 1, wherein the means performs error processing for notifying an abnormality when the difference between the current detection level and the previous detection level is not within the set value. Recording device. 3. The means sets the threshold value based on the previous detection level when the difference between the current detection level and the previous detection level is not within the set value. The inkjet recording device according to claim 1. 4. The ink jet recording apparatus according to claim 1, wherein the set value is a limit value at which there is no risk of erroneous detection of the recording material. 5. The ink jet recording apparatus according to claim 1, wherein the moving mechanism includes a carriage that mounts and moves the recording head and that is provided with the light amount detecting means. . 6. The ink jet recording apparatus according to claim 1, wherein the previous detection level is stored in the memory when the recording apparatus is shipped from the factory. 7. The recording head has an electrothermal converter that generates thermal energy that causes film boiling in the ink, as an energy generating element for ejecting the ink. The inkjet recording device according to item 1.