JP2013063601A - Liquid level determination device, inkjet recording device, and liquid level determination method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a detection device that does not perform mis-detection of the volume of an ink drop due to paper powder and dust, etc.SOLUTION: A liquid level determination device includes: a light receiving means that receives scattered light generated when the ink drop intersects the laser beam; and a mask 67 that interrupts the laser beam irradiating the photodiode 66. A detection device determines the volume of the ink drop based on the light received amount of the forward-scattered light received by the photodiode 66. Thereby, the effect is achieved to prevent the mis-calculation of the volume of the ink drop caused by mis-detection of interruption of the ray, when the substance other than the ink drop interrupts the ray.

Description

  The present invention relates to a liquid amount determination apparatus that determines a liquid amount of discharged droplets.

  2. Description of the Related Art Conventionally, an ink jet recording apparatus is known as one of image forming apparatuses such as a printer, a facsimile machine, a copying machine, a plotter, and a multifunction machine of these. The ink jet recording apparatus records images such as characters and graphics on paper by ejecting ink droplets from nozzles onto the conveyed paper.

  In an ink jet recording apparatus, when the ink viscosity increases or solidifies due to the evaporation of the solvent from the nozzle, or dust adheres to the nozzle, the volume of the ink droplets ejected from the nozzle may be reduced. is there. If recording is performed in a state where the volume of the ink droplet is reduced, a gap is generated in the image, and the image quality is deteriorated.

  In view of this, an inkjet recording apparatus has been proposed that calculates the volume of ejected ink droplets and adjusts the drive waveform of a nozzle that ejects ink droplets based on the calculated volume or the like (Patent Document 1). This ink jet recording apparatus measures the amount of ink droplets blocking the light beam at predetermined time intervals, obtains the cross-sectional shape in the ink droplet ejection direction from the measurement result, and crosses the ink droplet in the direction perpendicular to the ink droplet ejection direction. Is assumed to be circular, and the volume of the ink droplet is calculated.

  In addition, it has a detecting means in which a light source and an optical sensor are arranged so that the optical axis is substantially parallel to the arrangement surface of the ink droplet discharge ports, and based on the detection signal of the detecting means when the droplet is discharged into the light beam There has been proposed a droplet detection device that determines the ejection state of ink droplets (Patent Document 2). This droplet detection device detects the drop amount of the output signal from the ink drop detection signal, and calculates the droplet size using this drop amount.

  However, when the volume of the ink droplet is calculated based on the amount of the ink droplet that blocks the light beam by the conventional method, the blocking of the light beam may be erroneously detected due to the paper dust or dust blocking the light beam. was there. That is, when the conventional apparatus is used, when a substance other than the ink droplet blocks the light beam, there is a problem that the blockage of the light beam is erroneously detected and the volume of the ink droplet is erroneously calculated. .

  According to a first aspect of the present invention, there is provided an ejection unit that ejects a droplet, a light emitting unit that emits a laser beam so as to intersect a path of the droplet ejected by the ejection unit, and an optical axis of the laser beam. A light receiving means arranged to intersect and receiving forward scattered light generated when the droplet intersects the laser light; a light shielding means for blocking the laser light from irradiating the light receiving means; and the light receiving Determining means for determining the liquid amount of the droplet based on the received light amount of the forward scattered light received by the means.

  According to a fourth aspect of the present invention, there is provided an ejection unit that ejects droplets, a light emitting unit that emits laser light so as to intersect a path of the droplets ejected by the ejection unit, and a passage through which the laser light passes. A light receiving means for receiving forward scattered light generated when the liquid droplet intersects the laser light, and a light receiving amount of the forward scattered light received by the light receiving means. And a determination means for determining a liquid amount.

  According to a sixth aspect of the present invention, there is provided a discharge step of discharging a droplet, a light emission step of emitting a laser beam so as to intersect a path of the droplet discharged by the discharge step, and an optical axis of the laser beam. A light receiving means arranged so as to intersect with each other, does not receive the laser light, and receives a forward scattered light generated when the droplet intersects the laser light; and received in the light receiving process And a determination step of determining the liquid amount of the droplet based on the received light amount of the forward scattered light.

  The invention according to claim 7 is a discharge step of discharging a droplet, a light emission step of emitting a laser beam so as to intersect a path of the droplet discharged by the discharge step, and a passage through which the laser beam passes A light receiving means for receiving forward scattered light generated when the droplet intersects the laser light, and a light receiving amount of the forward scattered light received in the light receiving process. And a determination step for determining the liquid amount of the droplet.

  As described above, according to the present invention, the liquid amount determination device receives forward scattered light generated when the liquid droplet intersects with the laser light, and the liquid droplet amount determination apparatus receives the forward scattered light based on the received light amount of the forward scattered light. Determine the amount of liquid. Since the liquid amount determination device does not calculate the amount of droplets based on the amount that blocks the laser beam, when a substance other than the droplets blocks the light beam, the blocking of the light beam is erroneously detected and the liquid amount is erroneously determined. There is an effect of preventing the calculation.

1 is a schematic diagram of an ink jet recording apparatus including a detection device according to an embodiment of the present invention. It is the schematic diagram which looked at the vicinity of the printing position of the inkjet recording device provided with the detection apparatus which concerns on one Embodiment of this invention from the side surface. It is the schematic diagram which looked at the vicinity of the printing position of the inkjet recording device provided with the detection apparatus which concerns on one Embodiment of this invention from the upper surface. It is sectional drawing which showed the one cross section (AA) of FIG. It is a schematic diagram of the detection apparatus which concerns on one Embodiment of this invention arrange | positioned in the printing position of an inkjet recording device. It is a schematic diagram of the photodiode of a light receiving unit. It is a block diagram which shows the light-receiving part circuit of a light-receiving unit. It is a block diagram for demonstrating the control part of the inkjet recording device of this embodiment. It is the processing flowchart which showed the processing method of the liquid quantity determination. It is a schematic diagram of a detection waveform. It is explanatory drawing which showed the relationship between a particle size and the intensity | strength of scattered light. It is a schematic diagram of a detection waveform. It is a schematic diagram of the detection apparatus which concerns on the comparative example arrange | positioned in the printing position of an inkjet recording device. It is a detection waveform of the light-receiving unit of the detection apparatus which concerns on a comparative example. It is a schematic diagram which shows the other example of a photodiode.

<< Overall Configuration of Embodiment >>
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, the overall configuration of the present embodiment will be described with reference to FIGS. FIG. 1 is a schematic diagram of an ink jet recording apparatus including a detection apparatus according to an embodiment of the present invention. FIG. 2 is a schematic view of the vicinity of the printing position of the ink jet recording apparatus provided with the detection device according to the embodiment of the present invention as seen from the side. FIG. 3 is a schematic view of the vicinity of the printing position of the ink jet recording apparatus provided with the detection device according to the embodiment of the present invention, as viewed from above. FIG. 4 is a cross-sectional view showing one cross section (AA) of FIG.

  The ink jet recording apparatus 1 shown in FIG. 1 is also called a line printer, and is configured to record on a sheet as an example of a transported recording medium by disposing a head for a printing width. As shown in FIG. 1, an inkjet recording apparatus 1 includes a paper feeding unit 10 that loads and feeds paper as an example of a recording medium, a transport unit 20 that transports the fed paper, The head unit 30 that forms an image by ejecting ink droplets as an example of droplets onto the paper, the paper discharge unit 40 that includes a paper discharge tray on which the paper on which the image is formed, and the head unit 30 are maintained. A maintenance unit 50, a detection device 60 that detects an ink droplet as an example of a droplet, and a control unit 70 that controls the overall operation of the inkjet recording apparatus 1.

  The paper feed unit 10 includes a paper feed tray for stacking paper and a paper feed roller for feeding paper stacked in a paper feed cassette one by one. The paper feed tray is configured to be applicable to various paper sizes. The paper feed unit 10 is designed so that the paper size and paper direction (vertical / horizontal) can be distinguished when paper is loaded in the paper feed tray, and so that paper out and paper feeding errors can be detected. A sensor may be provided.

  The head unit 30 includes a head 31 for ejecting ink, a sub tank (not shown) for supplying ink to the head 31, and an ink cartridge (not shown) for supplying ink to the sub tank via a tube.

  The head 31 is provided with nozzles, from which, for example, yellow, cyan, magenta, and black inks are ejected. In the present embodiment, the head 31 has a piezo element. This piezo element pressurizes the ink supplied to the head 31. As a result, the head 31 ejects ink droplets from the nozzles. The size of the ejected ink droplet can be changed based on the driving waveform of the piezo element. The head 31 can also form a large size droplet by discharging a plurality of small droplets continuously and merging them.

  In the present embodiment, the plurality of heads 31 are arranged side by side in a staggered pattern so that the ink ejection direction is downward (see FIG. 3). The head unit 30 is not necessarily provided with a plurality of heads, and may be provided with one head as a line head. Further, the number of ink colors and the arrangement order of the heads 31 in the paper transport direction are not limited to the above configuration. The head unit 30 may include a supply pump unit in the ink cartridge loading section in order to supply the ink in the ink cartridge to the sub tank.

  The head unit 30 is driven by a motor (not shown), and moves between a position (printing position) on the paper transport unit 20 and a position on the maintenance unit 50 (see FIG. 1). In this case, the head unit 30 moves to a printing position on the transport unit 20 when printing is started. Further, the head unit 30 moves to a position on the maintenance unit 50 when printing is finished, when the power is shut off, or when the head 31 is cleaned.

  The maintenance unit 50 includes a cap, and caps the head 31 of the head unit 30 that has moved onto the maintenance unit 50. Thereby, the maintenance unit 50 prevents the ink from drying from the nozzle openings of the head 31.

  The transport unit 20 accommodates a roller composed of a driving roller 21 and a driven roller 22, an endless transport belt 23 stretched between these rollers, a suction fan 24 for sucking paper, and idle ink. And a waste liquid unit 25.

  The conveyor belt 23 moves around as the driving roller 21 is rotated by a motor (not shown). The distance (gap) between the head 31 and the conveyor belt 23 is not particularly limited, but can be about 1 mm. In addition, a plurality of suction holes 26 are formed in the transport belt 23 in a staggered pattern corresponding to the arrangement pattern of the heads 31 of the head unit 30 (see FIG. 3). The suction holes 26 are arranged uniformly over the entire circumference of the conveyor belt 23. As a result, the sheet is sucked onto the conveyor belt 23 by the suction fan 24 and is conveyed one by one by the circular movement of the conveyor belt 23. The shape of the suction hole 26 is not particularly limited, but is usually circular in order to accurately convey the paper.

  When the ink jet recording apparatus 1 performs continuous printing, the control unit 70 controls both the paper transport speed by the transport unit 20 and the paper feed speed by the paper feed unit 10. Thereby, the interval of the conveyed paper is adjusted according to the paper size and the printing speed. The printed paper is discharged to the paper discharge unit 40 and accumulated in the paper discharge tray.

  The waste liquid unit 25 detects the waste liquid tray that stores the ink ejected from the head 31 through the suction hole 26 of the transport belt 23, and that the ink stored in the waste liquid tray has reached a predetermined capacity limit. Sensor. Accordingly, the user can discard the ink in the waste liquid tray as waste liquid based on the detection of the sensor.

  The detection device 60 includes a light emitting unit 61 that emits laser light disposed on the left hand side with respect to the paper conveyance direction P in FIG. 3 and a light receiving unit 62 that is disposed on the right hand side with respect to the conveyance direction P. ing. In the present embodiment, eight sets of detection units are provided corresponding to each row of the heads 31 arranged perpendicular to the paper transport direction P.

  The control unit 70 controls the overall operation of the inkjet recording apparatus 1. Therefore, the control unit 70 includes storage devices such as a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory), which will be described later.

<Configuration of detection device>
Next, the configuration of the detection device 60 will be described with reference to FIGS. FIG. 5 is a schematic view of a detection apparatus according to an embodiment of the present invention that is disposed at a printing position of the inkjet recording apparatus. FIG. 6 is a schematic diagram of a photodiode of the light receiving unit. FIG. 7 is a block diagram illustrating a light receiving unit circuit of the light receiving unit.

  As shown in FIG. 5, each detection unit of the detection device 60 irradiates laser light, and detects forward scattered light generated when the ink droplets T ejected from the nozzles of the head 31 intersect the laser light. The light emitting unit 61 emits laser light so as to intersect the path of the ink droplet T ejected from the head 31. Therefore, the light emitting unit 61 includes a laser diode 63 as a light emitting element, a collimating lens 64 disposed near the laser diode 63 and condensing the laser light, and an aperture 65 for narrowing the beam diameter of the laser light. . The shape of the aperture 65 is determined according to the application and is not particularly limited. In the present embodiment, a shape having a circular hole is used.

  The light receiving unit 62 is arranged so as to intersect perpendicularly with the optical axis X of the laser light emitted from the light emitting unit 61, and receives a forward scattered light generated when the ink droplet T intersects the laser light. And a mask 67 for blocking the laser light from irradiating the photodiode 66, and a light receiving unit circuit 68 for converting a current output from the photodiode 66 into a voltage. Note that the light emitting unit 61 and the light receiving unit 62 are normally attached with high accuracy while adjusting the optical axis of the laser light emitted from the light emitting unit 61 using an attachment jig or the like. Further, the photodiode 66 does not necessarily intersect the optical axis X perpendicularly as long as it can detect forward scattered light.

  The photodiode 66 only needs to be larger than the beam diameter of the laser light emitted from the light emitting unit 61, and a known one is used depending on the application. In the present embodiment, the beam diameter on the light receiving surface of the laser beam is not particularly limited, but is 0.5 mm or less. In the present embodiment, the size of the photodiode 66 is not particularly limited, but is 5 mm × 5 mm or less.

  As shown in FIG. 6, a mask 67 for shielding laser light is provided on the upper surface of the center of the light receiving surface of the photodiode 66. The member of the mask 67 is preferably a black member that absorbs laser light without reflecting it. As a result, it is possible to suppress detection errors caused by reflection or disturbance of the laser beam.

  The area of the mask 67 is appropriately selected based on the beam diameter on the light receiving surface of the laser beam, but can be a square having sides with a length that is 1 mm to 1.5 mm larger than the normal beam diameter. In the present embodiment, the mask 67 has a square shape, but may be a polygon or a circle having the same diameter. The light emitting unit 61 irradiates the masked portion with laser light. As a result, the photodiode 66 detects forward scattered light at a light receiving portion other than the masked portion 67. In this case, since the photodiode 66 can detect forward scattered light in all directions on a plane perpendicular to the optical axis, the ink droplet T can be detected with high accuracy even if the output of the laser light is small.

  As shown in FIG. 7, the light receiving unit circuit 68 of the light receiving unit 62 includes a current-voltage conversion unit, a high-pass filter, and a low-pass filter. The current-voltage conversion unit performs current-voltage conversion and amplifies the current output from the photodiode 66 based on the amount of forward scattered light received. The high-pass filter and the low-pass filter obtain a detection waveform by deleting a frequency band that is not necessary for the signal detected by the photodiode. The output detection waveform is amplified by the operational amplifier until it reaches a predetermined level. The detection device 60 can electrically detect the ink droplet T based on the amount of forward scattered light received.

  The detection waveform output from the light receiving unit circuit 68 is used for determining the liquid amount of the ink droplet T. In the present embodiment, the liquid amount includes the volume, diameter, mass, and the like of the ink droplet T. As a result, it is possible to determine whether the nozzle of the head 31 is defective or the ejection state. If it is determined that the nozzle is missing, the inkjet recording apparatus 1 may move the head unit 30 onto the maintenance unit 50 and execute the recovery operation of the head 31 and the nozzle. Further, when it is determined that there is no problem in the ejection state, the inkjet recording apparatus 1 may start printing without performing the above recovery operation.

<<< Hardware Configuration and Functional Configuration of Control Unit >>>
The hardware configuration and functional configuration of the control unit 70 of the inkjet recording apparatus 1 of the present embodiment will be described with reference to FIG. FIG. 8 is a block diagram for explaining the control unit 70 of the inkjet recording apparatus 1 of the present embodiment.

  The control unit 70 of the inkjet recording apparatus 1 according to the present embodiment includes a CPU 101 that controls the overall operation of the inkjet recording apparatus 1, a ROM 102 that stores a predetermined program, a RAM 103 that is used as a work area for the CPU 101, and a power source for the inkjet recording apparatus 1. Non-volatile memory (NVRAM) 104 that retains data even while the image is shut off, various signal processing for image data, image processing such as rearrangement, or input / output signals for controlling the entire inkjet recording apparatus 1 ASIC (Application Specific Integrated Circuit) 105, I / F (Interface) 106 for transmitting / receiving data and signals to / from an external device such as a host computer, and I / O (Input) for inputting a detection waveform of the detection device 60 / Output) port 107.

  Further, the control unit 70 of the inkjet recording apparatus 1 is realized by operating according to a command from the CPU 101 according to a program stored in the ROM 102, and is realized by a conveyance control unit 71, a head control unit 72, and a maintenance control unit. 73, a detection control unit 74, and a liquid amount determination unit 75.

  The conveyance control unit 71 controls the operations of the paper feeding unit 10 and the conveyance unit 20 according to instructions from the CPU 101 according to a program stored in the ROM 102. For example, when the conveyance control unit 71 transmits a signal to start feeding, the sheet feeding roller of the sheet feeding unit 10 feeds the sheets stacked on the sheet feeding tray one by one. Further, when the conveyance control unit 71 transmits a signal indicating that the conveyance of the sheet is started, the driving roller 21 of the conveyance unit 20 is driven, and the conveyance belt 23 moves around.

  The head control unit 72 controls the operation of the head unit 30 according to a command from the CPU 101 according to a program stored in the ROM 102. For example, the head control unit 72 generates a drive waveform for driving and controlling the piezo element of the head 31 and performs control for ejecting ink.

  The maintenance control unit 73 controls the operation of the maintenance unit 50 according to a command from the CPU 101 according to a program stored in the ROM 102. For example, the maintenance control unit 73 performs control to cap the head 31 of the head unit 30 with the cap of the maintenance unit 50 by transmitting a signal to cap the head 31.

  The detection control unit 74 controls the operation of the detection device 60 according to a command from the CPU 101 according to a program stored in the ROM 102. For example, the detection control unit 74 performs control to cause the laser diode 63 of the light emitting unit 61 to emit light by transmitting a signal to emit laser light.

  The liquid amount determination unit 75 determines the liquid amount based on the area (light reception amount) of the detection waveform output by the detection device 60 according to a command from the CPU 101 in accordance with a program stored in the ROM 102.

<< Processing and Operation of Embodiment >>
Next, a processing method for determining the volume of the ink droplet T as an example of the liquid amount in the inkjet recording apparatus 1 according to the present embodiment will be described with reference to FIGS. 9 to 12. FIG. 9 is a process flow diagram showing a processing method for determining the liquid amount. FIG. 10 is a schematic diagram of a detected waveform. FIG. 11 is an explanatory diagram showing the relationship between the particle diameter in Mie scattering and the intensity of scattered light. FIG. 12 is a schematic diagram of a detection waveform of the light receiving unit 62.

  The liquid amount determination process starts when the I / O port 107 of the control unit 70 receives the detection waveform output from the light receiving unit 62 of the detection device 60 (step S1). The light receiving unit 62 detects forward scattered light for a time (Δt) from when the ink droplet T starts to intersect with the laser light (t1) to when it finishes intersecting (t2). For this reason, the detection waveform output from the light receiving unit 62 has a predetermined area (see FIG. 10).

Subsequently, the liquid amount determination unit 75 calculates the area of the detection waveform of the light receiving unit 62 (step S2). The area of the detection waveform of the ink droplet T is generally indicated by a value obtained by integrating the voltage variable with the time variable. Here, the area S of the detected waveform is obtained by the following equation.
S = 1/2 × (Δt × ΔV)

Subsequently, the liquid amount determination unit 75 calculates the ink volume based on the area value of the detection waveform (step S3). From the relationship between the diameter of the ink droplet T and the wavelength of the laser beam, it is considered that when the laser beam is irradiated to the ink droplet T, a light scattering phenomenon due to Mie scattering occurs. As shown in FIG. 11, in Mie scattering, the forward scattered light in the optical axis direction increases as the particle size increases. As a result, the area of the detection waveform of the light receiving unit increases in accordance with the size of the ink droplet T. For example, detection waveforms of forward scattered light in the optical axis direction of laser light of small ink droplets (3 pl), medium droplets (10 pl), and large droplets (20 pl) are as shown in FIG. In this case, the area value of the detection waveform is substantially proportional to the ink cross-sectional area. Therefore, the ink volume V can be calculated using the area value S of the detection waveform as the cross-sectional area of the ink droplet T.
V = 3/4 × S ^1.5

  In order to avoid the influence of direct light, it may be better to dispose the photodiode 66 away from the optical axis of the laser light in the light receiving unit 62. However, when the photodiode 66 is arranged away from the optical axis, the volume of the ink droplet T cannot be calculated accurately. The reason will be described with reference to FIGS. FIG. 13 is a schematic diagram of a detection device according to a comparative example arranged at a printing position of the inkjet recording apparatus. FIG. 14 is a detection waveform of the light receiving unit of the detection apparatus according to the comparative example.

  The detection device of FIG. 13 is different from the detection device 60 of the present embodiment in that the photodiode 66 is shifted from the optical axis X in the vertical direction. In Mie scattering, the light A scattered away from the optical axis increases as the particle size increases (see FIG. 11), but the amount of increase is small compared to the scattered light in the optical axis X direction. For example, the detection waveforms of ink droplets T of small droplets (3 pl), medium droplets (10 pl), and large droplets (20 pl) are as shown in FIG. That is, as the particle size increases, the change in the area value of the detection waveform becomes smaller, and it becomes difficult to calculate the ink volume.

<< Supplement of Embodiment >>
In the above embodiment, the liquid amount determination unit 75 is provided in the control unit 70 of the inkjet recording apparatus 1. However, the present invention is not limited to the above embodiment. The liquid amount determination unit 75 may be provided in an external information processing apparatus. In this case, the detection waveform of the light receiving unit 62 of the inkjet recording apparatus 1 is transmitted to an external information processing apparatus, and the liquid amount of the ink droplet T is determined by the liquid amount determination unit 75 of the external information processing apparatus.

  In the above embodiment, the mask 67 for shielding the laser beam is provided on the light receiving surface of the photodiode 66. However, the present invention is not limited to the above embodiment. Another embodiment will be described with reference to FIG. FIG. 15 is a schematic diagram illustrating another example of the photodiode 66. In the photodiode 66 of FIG. 15, a passing portion 69 through which the laser light L passes is formed. The passage portion 69 may be a space or a material through which laser light passes, such as glass or plastic. Thus, the photodiode 66 can receive forward scattered light generated when the ink droplet T intersects the laser light without receiving the laser light. The shape of the passage portion 69 is not limited to a quadrangle, and may be a polygon other than a quadrangle, a circle, an ellipse, or the like.

<< Main effects of embodiment >>
As described above, the detection device 60 according to the above-described embodiment blocks the photodiode 66 that receives the scattered light generated when the ink droplet T intersects the laser light and the laser light from irradiating the photodiode 66. And a mask 67. Accordingly, the detection device 60 determines the volume of the ink droplet T based on the amount of forward scattered light received by the photodiode 66. Since the detection device 60 of the present embodiment does not calculate the volume of the ink droplet T based on the amount that blocks the light beam of the laser beam, the blocking of the light beam is erroneously detected when a substance other than the ink droplet blocks the light beam. This has the effect of preventing the volume of ink droplets from being erroneously calculated.

  Further, the mask 67 of the detection device 60 of the above embodiment is provided on the photodiode 66. Thereby, there is an effect that it is possible to block the laser light from directly irradiating the photodiode 66.

  Moreover, the member of the mask 67 of the detection apparatus 60 of the said embodiment is a black member which absorbs a laser beam without reflecting. As a result, it is possible to suppress detection errors caused by reflection or disturbance of the laser beam.

  Further, the photodiode 66 of the detection device 60 of the above embodiment is replaced with one that is formed in an annular shape so as not to directly receive the laser beam. Thus, the photodiode 66 can receive forward scattered light in the vicinity of the optical axis without receiving the laser light without providing the mask 67.

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 10 Paper supply unit 20 Conveyance unit 21 Drive roller 22 Driven roller 23 Conveyor belt 24 Suction fan 25 Waste liquid unit 26 Suction hole 30 Head unit (an example of discharge means)
31 Head 40 Paper discharge unit 50 Maintenance unit 60 Detection device 61 Light emitting unit (an example of light emitting means)
62 Light receiving unit (an example of light receiving means)
63 Laser diode 64 Collimating lens 65 Aperture 66 Photo diode 67 Mask (an example of light shielding means)
68 Light-receiving unit circuit 69 Passing unit 70 Control unit 71 Transport control unit 72 Head control unit 73 Maintenance control unit 74 Detection control unit 75 Liquid amount determination unit (an example of determination means)

JP 2003-127430 A JP-A-2005-280351

Claims (7)

Discharging means for discharging droplets;
A light emitting means for emitting a laser beam so as to intersect with a path of the droplet ejected by the ejection means;
A light receiving means disposed so as to intersect with the optical axis of the laser light, and receiving forward scattered light generated when the droplet intersects the laser light;
Light shielding means for blocking the laser light from irradiating the light receiving means;
A liquid amount determination apparatus comprising: a determination unit configured to determine a liquid amount of the droplet based on a received light amount of the forward scattered light received by the light reception unit.   The liquid amount determination apparatus according to claim 1, wherein the light shielding unit is provided on the light receiving unit.   The liquid amount determination apparatus according to claim 1, wherein the light shielding unit includes a material that absorbs the laser light. Discharging means for discharging droplets;
A light emitting means for emitting a laser beam so as to intersect with a path of the droplet ejected by the ejection means;
A light receiving means for receiving forward scattered light generated when a passing portion through which the laser light passes is formed and the droplet intersects the laser light;
A liquid amount determination apparatus comprising: a determination unit configured to determine a liquid amount of the droplet based on a received light amount of the forward scattered light received by the light reception unit.   An ink jet recording apparatus comprising the liquid amount determining apparatus according to claim 1. An ejection process for ejecting droplets;
A light emitting step of emitting a laser beam so as to intersect the path of the droplets ejected by the ejection step;
A light receiving means arranged so as to intersect the optical axis of the laser light, not receiving the laser light, and receiving forward scattered light generated when the droplet intersects the laser light; and
And a determination step of determining a liquid amount of the droplet based on a received light amount of the forward scattered light received in the light receiving step. An ejection process for ejecting droplets;
A light emitting step of emitting a laser beam so as to intersect the path of the droplets ejected by the ejection step;
A light receiving unit in which a passing portion through which the laser beam passes is formed, and a light receiving step of receiving forward scattered light generated when the droplet intersects the laser beam;
And a determination step of determining a liquid amount of the droplet based on a received light amount of the forward scattered light received in the light receiving step.

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