JP2001113677A - Recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a convenient and inexpensive recorder in which a sensor for detecting the ink ejection state requires no cleaning and the effect of external light onto the sensor can be eliminated. SOLUTION: When the ink ejection state of an ink jet type recording head is detected using a photointerrupter type sensor, the light emitting element of that sensor is covered with a first protective member and the light receiving element of that sensor is covered with a second protective member. Air is taken externally into the first and second protective members and discharged from air outlets provided in the first and second protective members such that the optical path between the light emitting element and the light receiving element is not intercepted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a printing apparatus, and more particularly to a printing apparatus capable of detecting a discharge failure of a print head that performs printing in accordance with an ink jet system.

[0002]

2. Description of the Related Art A recording apparatus using a recording head according to an ink jet system prints an image on a recording medium such as paper, film, cloth, or the like by discharging minute ink droplets from fine nozzles provided in the recording head. Record. However, if dust, ink mist, or the like adheres to the fine nozzles, normal ink ejection is not performed, and white streaks are generated along the moving direction of the recording head, which may degrade image quality.

Therefore, conventionally, it has been necessary to monitor the state of ink ejection from the print head and perform printing control based on the monitoring result. For example, using a photo-interactive type sensor, the light emitted from the light emitting element of the sensor is blocked by ink droplets ejected from the recording head, and the change in the amount of light caused by the light blocking is detected by the light receiving element of the sensor. A method of monitoring the ejection state of the print head by detecting the print state has been proposed.

However, in such a method, while the recording apparatus is used for a long period of time, the ink ejected from the recording head is not adsorbed and absorbed by a recording medium such as paper, film, cloth, etc. And the floating thing gradually adheres to and accumulates on the light-emitting element and light-receiving element,
There has been a problem that the detection accuracy of the sensor that has detected the ejection state of minute ink droplets gradually decreases.

In order to solve such a problem, for example, US Pat. No. 5,255,009 discloses a method in which a cleaning member is provided in a recording apparatus and an optical portion of a sensor is always kept in a clean state. .

[0006]

However, in the above-mentioned prior art, the provision of the cleaning member makes the recording apparatus complicated and expensive, and if the apparatus is used for a long period of time, the cleaning member itself becomes dirty and maintenance is required. There was a problem.

Further, when detecting the ink ejection state from the recording head using a photo-interactive type sensor, the effect of external light on the light receiving element must be eliminated as much as possible in order to perform the detection with high accuracy. . However, the recording apparatus needs to be provided with an opening to supply the recording medium into the apparatus and to discharge the recording medium on which recording has been completed to the outside of the apparatus. It was not easy to do.

The present invention has been made in view of the above problems, and does not require cleaning of a sensor for detecting an ink discharge state, and can eliminate the influence of external light on the sensor, and is simple and inexpensive. It is an object to provide a simple recording device.

[0009]

In order to achieve the above object, a recording apparatus according to the present invention has the following arrangement.

That is, a printing apparatus capable of detecting the state of ink ejection from a print head in accordance with an ink jet system using a photo-interactive type sensor, comprising: a first protective member covering a light emitting element of the sensor; A second protection member that covers a light receiving element of the sensor, and an intake unit that takes in air from outside into the first and second protection members, wherein the first and second protection members have Is provided with an outlet for air taken in by the intake means so as not to block an optical path between the light emitting element and the light receiving element.

Here, it is desirable that the insides of the first and second protection members be black, and that the air pressure inside the first and second protection members be higher than the outside air pressure.

Further, it is desirable that a columnar projection is provided at the air outlet.

The light emitting element is an infrared LED for irradiating infrared light, the light receiving element is a phototransistor, the recording head has a plurality of recording elements, and ink liquid ejected from the plurality of recording elements is provided. A drop may be provided to block the infrared light. In this case, it is preferable that the light emitting element and the light receiving element are provided so that the optical axis of the infrared light intersects the arrangement direction of the recording elements of the recording head.

The above-mentioned recording head is a recording head for discharging ink by using thermal energy, and preferably includes a thermal energy converter for generating thermal energy to be applied to the ink.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a three-dimensional perspective view showing a detailed configuration of a printer having a recording head for performing recording in accordance with an ink jet system, which is a typical embodiment of the present invention.

As shown in FIG. 1, the recording head 5 is a cartridge type recording head having a built-in ink tank and which can be replaced with a new one when the ink runs out.

In FIG. 1, while the carriage 15 holds the recording head 5 with high precision, the carriage 15 moves in a direction (main scanning direction, arrow H direction) orthogonal to the recording paper P transport direction (sub-scanning direction, arrow G direction). Move back and forth. The carriage 15 is slidably held by a guide rod 16 and an abutting portion 15a. The carriage 15 reciprocates by pulley 1 driven by a carriage motor (not shown).
The recording signal and the electric power supplied to the recording head 5 at this time are supplied from an electric circuit of the apparatus main body by a flexible cable 19. Recording head 5 and flexible cable 1
9 is connected by pressing the contact points of each other.

A cap 20 is provided at the home position of the carriage 15 and functions as an ink receiver. The cap 20 is moved up and down as needed, and when it rises, it is in close contact with the recording head 5 and covers its nozzle to prevent evaporation of ink and adhesion of dust.

In this apparatus, in order to position the recording head 5 and the cap 20 so as to be relatively opposed to each other, a carriage home sensor 21 provided on the apparatus main body and a light shielding provided on the carriage 15 are provided. Board 15b
Is used. As the carriage home sensor 21, a transmission type photo interrupter is used. When the carriage 15 moves to the standby position, light emitted from a part of the carriage home sensor 21 is blocked by the light shielding plate 15b. Using the recording head 5
And that the cap 20 is at a relatively opposed position.

The recording paper P is fed upward from the lower side in FIG.
It is bent in the horizontal direction by the feed roller 2 and the paper guide 22 and is conveyed in the direction of arrow G (sub-scanning direction). The feed roller 2 and the discharge roller 6 are each driven by a recording motor (not shown), and a carriage 15
The recording paper P is conveyed in the sub-scanning direction with high precision in conjunction with the reciprocating movement of the recording paper P. Further, a spur 23 which is made of a material having high water repellency in the sub-scanning direction and comes into contact with the recording paper P only at its blade-shaped circumferential portion is provided. The spurs 23 are arranged at a plurality of locations facing the paper discharge roller 6 at predetermined intervals in the main scanning direction by a bearing member 23a. The recording paper P is guided and conveyed without affecting the recording paper P.

As shown in FIG. 2, the photo sensor 8 is arranged between the cap 20 and the end of the recording paper P at a position facing the nozzle row 5a of the recording head 5, and discharges from the nozzles of the recording head 5. This is a transmission type photo interrupter that directly and optically detects the ink droplet to be discharged.

FIG. 2 is an enlarged perspective view showing a detailed configuration near the photosensor of the printer shown in FIG.

The photo sensor 8 used here uses an infrared LED as a light emitting element, a lens is integrally formed on the LED light emitting surface, and a light emitting section 81 capable of projecting a light beam substantially parallel to the light receiving element. And a light receiving section 82 using a phototransistor as a light receiving element.

The optical axis 83 connecting the light emitting section 81 and the light receiving section 82 is disposed so as to intersect the nozzle row 5a of the recording head 5 at an angle θ, and the interval between the light emitting section 81 and the light receiving section 82 is 5 is wider than the nozzle row 5a. As the ink drops pass through the detection range, the ink drops block the light from the light emitting side and reduce the amount of light to the light receiving side,
A change in the output of the phototransistor is provided by being provided in the light receiving section 82.

In FIG. 2, P1 is an area on which recording has already been performed on the recording paper P, P2 is an area on which recording is to be performed, and S1, S2, and Sn are drops of ink droplets ejected from the recording head. Reference numeral 71 denotes a scale attached in parallel along the moving direction of the recording head 5, and reference numeral 72 denotes a linear encoder attached to the recording head 5.

The linear encoder 72 detects the position of the recording head 5 by reading the scale of the scale 71 while the recording head 5 is moving. This position serves as a reference in image recording, realizes ideal ejection of ink droplets on the recording paper P, contributes to improvement in image quality, and also serves as reference information for detecting a defective nozzle described later.

A member 84 is a member for receiving ink droplets ejected for detecting a defective nozzle. The member 84 is attached to a support base 85. And ink is discharged together with the water by a suction pump (not shown).

It should be noted that, as the number of nozzles provided in the recording head increases, it is necessary to detect ink droplets stably over a relatively long distance. It is more advantageous to use one. Therefore, for example, a semiconductor laser or another laser light source may be used in addition to the infrared light from the LED. Ink droplets are sequentially ejected from the recording head in units of one nozzle. Since the ejection cycle is a short cycle of 200 μs or less, a photosensor 8 having a high-speed response, such as a PIN silicon photodiode, is used. It is desirable. Further, the output of the light source may be adjusted according to the characteristics of the photosensor 8 (such as the absolute rating of the intensity of incident light), and the light amount may be adjusted using, for example, an ND filter.

FIG. 3 is a block diagram showing a detailed configuration of the light emitting section 81 and the light receiving section 82.

In FIG. 3, reference numeral 81a denotes an infrared LED serving as a light emitting element; and 82a, a phototransistor which receives light emitted from the light emitting element and generates an electric signal corresponding to the amount of received light.

As can be seen from FIG. 3, the light emitting section 81 and the light receiving section 82 protect the infrared LED 81a and the phototransistor 82a from dust and ink mist in the air, respectively, and protect the infrared LED 81a and the phototransistor 82a from entering external light. , 82b. In addition, the front surface of the light receiving surface of the phototransistor 82a is, for example, 0.7 mm ×
A hole of about 0.7 mm is formed on the optical axis 83 and the infrared ray L
In the entire area between the ED 81a and the phototransistor 82a, the detection range is narrowed to 0.7 mm in the height direction and 0.7 mm in the width direction.

The reason is that the ink droplet is smaller than the light flux of the light beam and the diameter of the sensor by 1/10 or less, and the amount of change in the amount of light obtained by the sensor is also small. , It is possible to increase the ratio (S / N ratio) between the amount of light obtained when the ink droplet is present in the area and the amount of light obtained when the ink droplet is not present in the light beam. This is because accuracy can be improved.

The means and shape for narrowing the detection area are not limited to the pinholes of the mold member, and slits or the like may be used.

Further, as shown in FIG. 3, the protective members 81b and 82b are provided with openings 81c and 81d, respectively, which do not block the light flux around the optical axis 83, and an air suction port 8b.
1d and 82d are provided, and air taken in in the direction of the arrow by an air fan 86 driven by a motor (not shown) and sufficiently taken in from the outside by a filter 87 passes through a tube 88. Protecting members 81b, 82b from the air suction holes 81d, 82d
Sent to

Therefore, since the insides of the protection members 81b and 82b are always at a slightly higher pressure than the outside air pressure, the inhaled air transfers the air from the protection members 81b and 82b to the outside through the openings 81c and 82c. It is being sent out. Therefore, the dust and the ink mist floating without being attached to and absorbed by the recording medium are protected by the protection members 81b and 82.
Even in the vicinity of b, these do not enter the insides of the protection members 81b and 82b, so that the infrared LED 81a and the phototransistor 82a can always be kept in a clean state.

FIG. 4 is a perspective view showing the appearance of the light emitting section 81 and the light receiving section 82.

FIG. 5 is a block diagram showing a control configuration of the printer shown in FIG.

In FIG. 5, reference numeral 24 denotes a control unit for controlling the entire apparatus. The control unit 24 includes a CPU 25 and a CP.
A ROM 26 storing a control program and various data executed by the U 25, a RAM 27 used as a work area when the CPU 25 executes various processes, and a RAM 27 for temporarily storing various data, A head controller 48 and the like for controlling the recording operation are provided.

As shown in FIG. 5, the recording head 5 is connected to a control unit 24 via a flexible cable 19, and the flexible cable 19 is connected to the recording unit 5 by the control unit 24.
, A control signal line and an image signal line. The output of the photo sensor 8 is transferred to the control unit 24, and can be analyzed by the CPU 25 via the head controller 48. The carriage motor 30 is a motor drive circuit 32
The motor is rotatable according to the number of pulse steps. Further, the control unit 24 controls the carriage motor 30 via a motor drive circuit 33 and the transport motor 31 via a motor drive circuit 32, and inputs an output from the carriage home sensor 21.

Further, the control section 24 has a printer interface 54 for receiving recording commands and recording data from an external computer 56. Further, the control unit 24 is connected to an operation panel 58 on which the apparatus user performs various operations and instructions. The operation panel 58 is provided with an LCD 59 for displaying a message.

Next, the process of monitoring the ink ejection state using the recording apparatus having the above configuration will be described with reference to the flowchart shown in FIG. This process is executed as a part of the preliminary ejection operation performed before the actual printing operation.

First, in step S10, the infrared LED 8
1a is emitted, and in step S82, the carriage 15
Is moved to the position of the photo sensor 8, and preliminary ejection of ink is performed from the recording head 5 so as to cross the LED light. Next, in step S83, the phototransistor 8
At 2a, the LED light is received.

Further, in step S40, it is checked whether or not the decrease (ΔL) in the amount of received light in the phototransistor 82a is equal to or less than a predetermined threshold (TH). here,
If ΔL ≦ TH, the process proceeds to step S50, and it is determined that the ink ejection is normal. On the other hand, ΔL
If> TH, the process proceeds to step S60, where it is determined that there is an ink ejection failure.

Here, although not described in detail, if it is determined that the ejection is defective, the suction recovery process or the wiping process is automatically executed, or a warning message is displayed on the LCD 59. The user is urged to take some action (for example, recovery of suction by manual operation or replacement of the recording head).

Therefore, according to the embodiment described above, the protection members 81b and 82b for covering the infrared LED 81a and the phototransistor 82a are provided, and the inside thereof is always higher than the outside air pressure to prevent the air from flowing into the inside. By this, floating particles and ink mistakes
1a and the phototransistor 82a, and the influence of external light on the infrared LED 81a and the phototransistor 82a can be reduced. it can.

The appearance of the protection members 81b and 82b is as follows.
The shape is not limited to the shape as shown in FIG. 4. For example, as shown in FIG. 7, a columnar projection 89 may be provided from the opening to suppress the invasion of external light.
Further, the shape may be rounded so as to reduce the flow resistance of the air.

Further, in order to take in air into the inside of the protection members 81b and 82b, air may be continuously sent by a pump instead of the air fan 86, and when the recording apparatus is used in a factory or the like, it is usually used. Compressed air laid in the factory can be used instead.

Further, by blackening the insides of the protection members 81b and 82b, even if a small amount of external light enters, the reflection inside the protective members 81b and 82b is suppressed, and the entry of external light into the phototransistor 82a is further reduced. And the accuracy of detecting the ink ejection state can be further improved.

The above-described embodiment is particularly provided with a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for causing ink to be ejected even in an ink jet recording system. By using a method in which a change in the state of the ink is caused by energy, it is possible to achieve higher density and higher definition of recording.

The typical configuration and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,740.
It is preferable to use the basic principle disclosed in the specification of Japanese Patent No. 796. This method can be applied to both the so-called on-demand type and continuous type. In particular, in the case of the on-demand type, liquid (ink)
By applying at least one drive signal corresponding to the recorded information and providing a rapid temperature rise exceeding the nucleate boiling to an electrothermal transducer arranged corresponding to the sheet or the liquid path holding the Since thermal energy is generated in the electrothermal transducer and film boiling occurs on the heat-acting surface of the recording head, bubbles in the liquid (ink) corresponding to this drive signal on a one-to-one basis can be formed. It is valid. By discharging the liquid (ink) through the discharge opening by the growth and contraction of the bubble, at least one droplet is formed. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of the liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable.

As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further, if the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

As the configuration of the recording head, in addition to the combination of the discharge port, the liquid path, and the electrothermal converter (linear liquid flow path or right-angle liquid flow path) as disclosed in the above-mentioned respective specifications, A configuration using U.S. Pat. No. 4,558,333 or U.S. Pat. No. 4,459,600, which discloses a configuration in which a heat acting surface is arranged in a bent region, is also included in the present invention. In addition, for multiple electrothermal transducers,
JP-A-59-123670 which discloses a configuration in which a common slot is used as a discharge part of an electrothermal transducer, and JP-A-59-123670 which discloses a configuration in which an opening for absorbing a pressure wave of thermal energy corresponds to a discharge part. A configuration based on 138461 may be adopted.

Further, as a full-line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus, the length is determined by combining a plurality of recording heads as disclosed in the above specification. This may be either a configuration satisfying the above requirements or a configuration as a single recording head formed integrally.

In addition to the cartridge type recording head in which the ink tank is provided integrally with the recording head itself described in the above embodiment, the recording head is electrically connected to the apparatus main body by being mounted on the apparatus main body. A replaceable chip-type recording head, which enables a simple connection and supply of ink from the apparatus main body, may be used.

It is preferable to add recovery means for the print head, preliminary auxiliary means, and the like to the configuration of the printing apparatus described above, since the printing operation can be further stabilized. Specific examples thereof include capping means for the recording head, cleaning means, pressurizing or suction means, preheating means using an electrothermal transducer or another heating element or a combination thereof. It is also effective to provide a preliminary ejection mode for performing ejection that is different from printing, in order to perform stable printing.

Further, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, but may be an integral recording head or a combination of plural recording heads. Alternatively, the apparatus may be provided with at least one of full colors by color mixture.

In the above-described embodiment, the description has been made on the assumption that the ink is a liquid. However, even if the ink solidifies at room temperature or lower, it is possible to use an ink that softens or liquefies at room temperature. Or, in the ink jet method, generally, the temperature of the ink itself is controlled within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range.
It is sufficient that the ink is in a liquid state when the use recording signal is applied.

In addition, in order to positively prevent temperature rise due to thermal energy as energy for changing the state of the ink from a solid state to a liquid state, the temperature is positively prevented.
Alternatively, in order to prevent evaporation of the ink, an ink which solidifies in a standing state and liquefies by heating may be used. In any case, the application of heat energy causes the ink to be liquefied by application of the heat energy according to the recording signal and the liquid ink to be ejected, or to start to solidify when reaching the recording medium. The present invention is also applicable to a case where an ink having a property of liquefying for the first time is used. In such a case, as described in JP-A-54-56847 or JP-A-60-71260, the ink is held in a liquid state or a solid state in the concave portion or through hole of the porous sheet. It is good also as a form which opposes an electrothermal transducer. 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 to the above, the recording apparatus according to the present invention may be provided not only as an image output terminal of an information processing apparatus such as a computer but also integrally or separately, a copying apparatus combined with a reader, etc. It may take the form of a facsimile machine having functions.

Even if the present invention is applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), an apparatus (for example, a copying machine, a facsimile) including one device Device).

Another object of the present invention is to provide a storage medium storing a program code of software for realizing the functions of the above-described embodiments to a system or apparatus, and to provide a computer (or CPU) of the system or apparatus.
And MPU) read and execute the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD
-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) running on the computer based on the instruction of the program code. ) May perform some or all of the actual processing, and the processing may realize the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, based on the instructions of the program code, It goes without saying that the CPU included in the function expansion board or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0067]

As described above, according to the present invention, when the state of ink ejection from the recording head according to the ink jet system is detected using a photo-interactive type sensor, the light emitting element of the sensor is the first light emitting element. The light-receiving element of the sensor is covered with a protective member, the light-receiving element of the sensor is covered with a second protective member, and air is taken in from the outside into the first and second protective members. Since the air is exhausted from the air outlets provided in the first and second protection members so as not to block the optical path between them, dust and ink mist in the air may adhere to and accumulate on the light emitting element and the light receiving element. This eliminates the need for cleaning the sensor for detecting the ink ejection state, and at the same time prevents external light from being incident on these elements. There is an effect that it can maintain the detection state always with high accuracy.

Further, since a mechanism for cleaning the sensor is not required, the structure of the apparatus can be simplified and the production cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a three-dimensional perspective view showing a detailed configuration of a printer including a recording head that performs recording according to an ink jet system, which is a typical embodiment of the present invention.

FIG. 2 is an enlarged perspective view showing a detailed configuration near a photo sensor of the printer shown in FIG.

FIG. 3 is a block diagram illustrating a detailed configuration of a light emitting unit 81 and a light receiving unit 82;

FIG. 4 is a perspective view showing the appearance of a light emitting unit 81 and a light receiving unit 82.

FIG. 5 is a block diagram showing a control configuration of the printer shown in FIG.

FIG. 6 is a flowchart illustrating a process of monitoring an ink ejection state.

FIG. 7 is a perspective view showing an appearance of a light emitting unit 81 and a light receiving unit 82 according to another embodiment.

[Explanation of symbols]

 5 Recording Head 5a Nozzle Array 8 Photo Sensor 15 Carriage 19 Flexible Cable 21 Carriage Home Sensor 24 Control Unit 25 CPU 26 ROM 27 RAM 30 Carriage Motor 32, 33 Motor Drive Circuit 48 Head Controller 54 Printer Interface 56 External Computer 58 Operation Panel 59 LCD 71 Scale 72 Linear encoder 80 Mold member 81 Light emitting part 81a Infrared LED 81b, 82b Protective member 81c, 82c Opening 81d, 82d Inlet 82 Light receiving part 82a Phototransistor 83 Optical axis 86 Air fan 87 Filter 88 Tube P Recording paper

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasushi Yasura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Shigeru Watanabe 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (72) Inventor Masashi Shimizu 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term (reference) 2C056 EA24 EB07 EB40 FA03 KD06

Claims (7)

[Claims] 1. A printing apparatus capable of detecting a state of ink ejection from a printing head according to an ink jet system using a photo-interactive type sensor, comprising: a first protection member covering a light emitting element of the sensor; A second protection member that covers a light receiving element of the sensor; and an intake unit that takes in air from outside into the first and second protection members, wherein the first and second protection members include The recording apparatus according to claim 1, further comprising a discharge port for air introduced by the intake unit so as not to block an optical path between the light emitting element and the light receiving element. 2. The recording apparatus according to claim 1, wherein the insides of the first and second protection members are black. 3. The recording apparatus according to claim 1, wherein the air pressure inside the first and second protection members is higher than the air pressure outside. 4. The recording apparatus according to claim 1, wherein a cylindrical projection is further provided at the air outlet. 5. The light emitting element is an infrared LED that emits infrared light, the light receiving element is a phototransistor, the recording head has a plurality of recording elements, and is ejected from the plurality of recording elements. 2. The recording apparatus according to claim 1, wherein an ink droplet is provided so as to block the infrared light. 6. The light-emitting element and the light-receiving element according to claim 5, wherein the light-emitting element and the light-receiving element are provided such that an optical axis of the infrared light intersects with an arrangement direction of recording elements of the recording head. Recording device. 7. The recording head according to claim 1, wherein the recording head ejects ink using thermal energy, and includes a thermal energy converter for generating thermal energy applied to the ink. Item 2. The recording device according to Item 1.