JPH0994959A - Ink jet recorder and ink detecting method for the recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the presence or absence of ink by detecting the infinitesimal change of a signal due to the discharged ink droplet and amplifying the change amount. SOLUTION: The ink jet recorder comprises a light emitting element 101 and a light receiving element 102 provided at predetermined positions in the moving region of an ink jet head to detect the ink discharged from the head. When the light quantity arriving at the element 102 is reduced by the ink droplet discharged from the head, the change of the reduced current is amplified by a change amount amplifier 105, and the ink discharge amount from the head is determined according to the pulse signal for comparing the amplified signal with a predetermined voltage.

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 performing recording by moving a carriage equipped with an ink jet head relative to a recording medium, and an ink detecting method in the apparatus.

[0002]

2. Description of the Related Art As a method for detecting the presence or absence of ink in an ink tank (ink cartridge) provided in an inkjet head in an inkjet printer,
Various methods have been proposed. For example, there is a method of detecting the presence or absence of ink by ejecting ink droplets between photo interrupters, simply amplifying the output of the photo interrupter, and comparing the amplified signal level with a reference voltage by a comparator. is there. Further, in order to detect the presence or absence of ink, there is also a method in which a mark for detecting the presence or absence of ink is printed on a recording medium, and it is determined by a reflective photosensor whether or not the detection mark is properly printed.

[0003]

However, in the former method among the conventional methods, a high-definition and high-quality image is desired with the advance of the technology in recent years, and high resolution of the ink jet recording apparatus is achieved. Then, the ejected ink droplets tend to be smaller than before. In addition, due to the mechanical restrictions of the photo interrupter, if the smaller ink droplet cannot sufficiently block the light reaching the light receiving element, the output of the photo interrupter changes too much from the steady state. Therefore, it is difficult to determine the presence or absence of ink by such a method.

Further, in the latter mark method, although the detection accuracy is high, in order to detect the presence or absence of ink, it is necessary to record an unnecessary mark on the recording medium.
Therefore, the recording medium is wastefully used, and a sensor for reading the mark with high accuracy is required.

The present invention has been made in view of the above-mentioned conventional example, and detects the presence or absence of ink by detecting a minute change in a signal due to an ejected ink droplet and amplifying the change amount. The present invention relates to an inkjet recording device and an ink detection method in the device.

It is another object of the present invention to provide an ink jet recording apparatus which can detect even minute ink droplets by using a photo interrupter, and an ink detecting method in the apparatus.

[0007]

In order to achieve the above object, the ink jet recording apparatus of the present invention has the following constitution. That is, an inkjet recording apparatus that performs recording by moving a carriage equipped with an inkjet head relative to a recording medium, is provided at a predetermined position within a moving region of the inkjet head, and is ejected from the inkjet head. Detecting means for detecting the ink and outputting a detection signal, an amplifying means for amplifying a variation of the detection signal, and an ink ejection amount from the inkjet head based on a signal output from the amplifying means. And a determining means.

In order to achieve the above object, the ink detecting method in the ink jet recording apparatus of the present invention comprises the following steps. That is, a method of detecting ink in an inkjet recording apparatus that performs recording by moving a carriage equipped with an inkjet head relative to a recording medium, the method comprising: moving the inkjet head to a predetermined position; Presence or absence of ink ejection by amplifying a change in the output signal from the light receiving element using a step of ejecting ink from the inkjet head and a photo interrupter having a light emitting element and a light receiving element provided at the predetermined position. To detect.

[0009]

According to the present embodiment, the detection means includes a light emitting element and a light receiving element, and the light emitted from the ink jet head between the light emitting element and the light receiving element reaches the light receiving element. A detection signal based on the amount of change is output.

Further, according to the present embodiment, the ink jet head ejects ink onto the optical axes of the light emitting element and the light receiving element.

Further, according to the present embodiment, the amplifying means is
It has a capacitor for inputting a signal from the detecting means and an amplifier circuit for amplifying the current passing through the capacitor.

Further, according to the present embodiment, the detecting means is
And a comparator for comparing a first voltage value according to the output current of the light receiving element and a second voltage value generated with a predetermined time constant according to the change of the output current of the light receiving element, and comparing the two. The output of the container is used as the detection signal.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, the structure of the ink jet recording apparatus according to the embodiment of the present invention will be described in detail with reference to FIGS.

FIG. 2 is a side sectional view showing the construction of an ink jet recording apparatus for performing recording by a recording head according to the ink jet system which is an embodiment of the present invention.

In FIG. 2, A is a recording unit for performing recording according to an ink jet system, B is a sheet feeding unit for separating recording media such as recording sheets P stacked in a sheet feeding cassette 1 one by one and supplying them to the recording unit A. It is a department.

First, the flow of the recording paper P will be described.
The recording paper P stacked in the paper feed cassette 1 of the paper feed unit B is picked up by the paper feed roller 2 and the retard roller 3, and fed to the recording unit A by the rotation of the paper feed roller 2. In the recording unit A, the recording head 5 ejects ink onto the recording paper P to perform recording, and the recording paper P is conveyed in accordance with the recording. When the recording for one page is completed, the recording paper P is discharged by the rotation of the paper discharge roller 6 and is stacked on the paper discharge stacker 7.

Next, the specific construction of the paper feed section B will be described.

In FIG. 2, the paper feed cassette 1 for accommodating a plurality of recording papers P is provided with an intermediate plate 4 for accommodating the recording papers P. The middle plate 4 is urged upward from the back surface by a middle plate spring 10 arranged to face the feeding roller 2. Further, the middle plate 4 is pressed downward by a cam or the like in the standby state for feeding, so that the recording paper P can be easily replenished when the recording paper P becomes small or runs out.

On the other hand, when the recording signal is detected and the paper feeding operation is started, the downward pressing of the intermediate plate 4 by the cam or the like is released,
The recording paper P is picked up by the paper feed roller 2.
The retard roller 3 is at a position facing the paper feed roller 2 and changes the position of the recording paper P in conjunction with the intermediate plate 4. When the paper feeding operation is performed, the uppermost one sheet of the recording paper P, which is urged upward by the middle plate 4 and picked up by the paper feeding roller 2, serves as the paper feeding roller 2 and the retard roller 3 in the J section. They are separated and fed by cooperating action. The recording paper P separated and fed in this manner is nipped so as to be sufficiently wrapped around the feeding roller 2 and conveyed to the recording unit A.

Next, the discharge mechanism of the recording paper P recorded in the recording section A will be described.

The recording paper P ejected by the paper ejection roller 6 is ejected and stacked on the paper ejection stacker 7. The paper discharge stacker 7 is provided with a paper discharge auxiliary tray 9 whose center of rotation is the hinge K, and when the recording paper P to be used is long, the paper discharge auxiliary tray 9 is rotated and discharged. The total length of the paper stacker 7 can be increased in the paper discharge direction of the recording paper P. Further, the paper discharge stacker 7 has a structure that also serves as a cover of the paper feed cassette 1. The paper discharge stacker 7 and the paper discharge auxiliary tray 9 are provided with a plurality of ribs (not shown), and the recording paper P on which recording is performed slides on the plurality of ribs and is sequentially stacked. .

Next, the structure of the recording section A will be described in detail with reference to FIG.

FIG. 3 is a three-dimensional perspective view showing the detailed structure of the recording section A. As shown in FIG. 3, the recording head 5 is a cartridge-type recording head that has an ink tank built-in and can be replaced with a new one when the ink is exhausted.

Here, the principle of ink ejection from the recording head 5 will be described. The recording head 5 generally has a fine liquid discharge port (orifice), a liquid passage and an energy acting portion provided in a part of this liquid passage, and energy for generating droplet forming energy for acting on the liquid in the acting portion. And a generator.

The energy generating section uses an electromechanical transducer such as a piezo element, irradiates electromagnetic waves such as a laser and causes the liquid there to absorb the heat to generate heat, and the generated heat causes droplets to be generated. There are those that are made to eject and fly, or those that are made to heat the liquid by an electrothermal converter and eject the liquid. Among them, in a recording head using a method of ejecting a liquid by thermal energy, liquid ejection ports (orifices) for ejecting recording liquid droplets to form flying liquid droplets can be arranged at high density. Therefore, it is possible to record at high resolution.

Further, the recording head using the electrothermal converter as the energy generating portion can be easily miniaturized as a whole, and the IC technology and the micro-technology which have been remarkably improved in the technological progress and reliability in the recent semiconductor field. Since the advantages of processing technology can be fully utilized and it is easy to make it long and flat (two-dimensional), it is easy to make multiple nozzles and high-density mounting, and mass production is possible. It is also possible to reduce the manufacturing cost.

A recording head manufactured through a semiconductor manufacturing process using an electrothermal converter in the energy generating section as described above is generally provided with a liquid passage corresponding to each ink ejection port, and each liquid passage has a liquid passage. An electrothermal converter is provided as a means for applying thermal energy to the liquid that fills the liquid and ejecting the liquid from the corresponding ink ejection port to form droplets for flight. The liquid is supplied from a common liquid chamber that is in communication with each other.

The configuration of the recording unit A will be described with reference to FIG.

In FIG. 3, the carriage 15 holds the recording head 5 with high precision, and in the direction (main scanning direction, arrow H direction) orthogonal to the conveying direction of the recording paper P (sub scanning direction, arrow G direction). It is moved back and forth. The carriage 15 includes a guide rod 16, a belt 18 and a carriage 15.
It is slidably held by an abutting portion 15a for fixing and. The reciprocating movement of the carriage 15 is performed by a pulley 17 and a timing belt 18 driven by a carriage motor 30 (FIG. 4). Supplied from the circuit. The recording head 5 and the flexible cable 19 are connected by press-contacting each other. A cap 20 is provided at the home position of the carriage 15 of the recording unit A and functions as an ink receiving unit. The cap 20 moves up and down as needed, and when it rises, it comes into close contact with the recording head 5 to cover its nozzle portion and prevent evaporation of ink and adhesion of dust.

In this apparatus, the recording head 5 and the cap 2
A carriage home sensor 21 provided on the apparatus main body and a light shielding plate 15b provided on the carriage 15 are used for positioning so that 0 and 0 are relatively opposed to each other. A transmission type photo interrupter is used for the carriage home sensor 21, and when the carriage 15 moves to the standby position, the light emitted from a part of the carriage home sensor 21 is blocked by the light shielding plate 15b. By utilizing this, it is detected that the recording head 5 and the cap 20 are relatively opposed to each other.

The recording paper P is fed upward from the lower side in the drawing,
The sheet is bent in the horizontal direction by the feeding roller 2 and the paper guide 22 and is conveyed in the arrow G direction (sub-scanning direction). The feeding roller 2 and the paper discharging roller 6 are respectively provided with a conveyance motor 31.
The recording paper P is driven by the rotation of (FIG. 5) and, if necessary, interlocks with the reciprocating movement of the carriage 15 to convey the recording paper P with high accuracy in the sub-scanning direction. Further, in the sub-scanning direction, there is provided a spur 23 which is made of a material having high water repellency and which comes into contact with the recording paper P only at its blade-shaped circumferential portion. The spur 23 is the discharge roller 6
The bearing member 23a is provided at a plurality of positions at predetermined positions in the main scanning direction at a position facing each other, and even if the unfixed image on the recording paper immediately after recording is contacted, the image is not affected and recording is performed. The paper P is guided and conveyed.

The ink detecting section 8 has a light emitting element (LED) 101 and a light receiving element (phototransistor) 102 which will be described later with reference to FIG. 1, and as shown in FIG.
0 and the paper edge of the recording paper P are arranged at positions facing the nozzle row 5c of the recording head 5, and the ink droplet rows ejected from the plurality of nozzles of the recording head 5 are arranged in the longitudinal direction of the nozzles. A transmission type phototransistor that directly optically detects when viewed from the direction is provided, and the ink-free state of the recording head 5 can be determined from its output. The ink detection unit 8 used here uses an infrared LED for the light emitting element 101, and a lens is integrally formed on the light emitting surface of the infrared LED, so that light can be projected substantially parallel to the light receiving element 102.
Further, on the light receiving surface of the light receiving element 102, a 0.7 mm × 0.7 mm hole is formed on the optical axis by a molding member, and the detection range is set in the height direction in the entire area between the light receiving element 101 and the light emitting element 102. 0.7 mm, width direction 0.7 m
I have narrowed down to m.

The optical axis connecting the light emitting element 101 and the light receiving element 102 is arranged parallel to the nozzle row 5c of the recording head 5, and the distance between the light receiving element 101 and the light receiving element 102 is
When the length of the nozzle row 5c of the recording head 5 is longer and the optical axis thereof coincides with the position of the nozzle row 5c of the recording head 5, all ink droplets ejected from each nozzle of the recording head 5 are emitted from the light emitting element 101. It is configured such that it can pass through the detection range between the light receiving elements 102. Then, when the ink droplet passes through the detection range, the amount of light that the ink droplet blocks the light from the light emitting element 101 and reaches the light receiving element 102 is reduced, and thus the output of the phototransistor, which is the light receiving element 102, changes. Is obtained and the ink ejection amount is detected.

Incidentally, in order to position the nozzle row of the recording head 5 and the ink detecting section 8 so as to be relatively opposed to each other, similarly to the positioning with the cap 20, a carriage home sensor provided in the main body of the apparatus. 21 is used.

In this embodiment, as shown in FIG. 4, the distance (L) from the position of the nozzle row 5c of the recording head 5 at the home position (HP) to the optical axis of the photo sensor 8 is set to the carriage 15. It is set as a constant in a control program for converting the number of steps of the driven carriage motor 30 and executing the recording operation in advance. In this way, after detecting the home position, the carriage 15 is moved by a certain amount, whereby the position of the ink ejection row of the recording head 5 and the optical axes of the light emitting element 101 and the light receiving element 102 of the ink detection unit 8 are set. Are accurately positioned.

FIG. 5 is a block diagram showing the control arrangement of the ink jet recording apparatus of this embodiment.

In FIG. 5, reference numeral 24 is a control unit for controlling the entire apparatus, and the control unit 24 is a CPU 25 and a CP.
It has a ROM 26 that stores a control program executed by the U 25 and various data, and a RAM 27 that is used as a work area when the CPU 25 executes various processes and that temporarily stores various data. .

As shown in FIG. 5, the recording head 5 is connected to the control section 24 via a flexible cable 19, and the flexible cable 19 includes a control signal line from the control section 24 to the recording head 5, an image signal line and the like. Has been.
The output of the ink detection unit 8 is input to the control unit 24,
The CPU 25 can analyze the ink ejection amount according to the pulse width. The carriage motor 30 rotates according to the phase excitation signal output from the motor drive circuit 32 based on the signal from the control unit 24. Further, the control unit 24 controls the carriage motor 3 via the motor drive circuit 33.
0 controls the rotation of the carry motor 31 via the motor drive circuit 32.

Furthermore, the control unit 24 is a printer / receiver which receives a recording command and recording data from the external computer 56.
The interface 54 and the like are connected. Control unit 2
4 is connected to an operation panel 58 for the user of the apparatus to perform various operations and instructions. The operation panel 58 has a display unit (L) for displaying various messages to the operator.
CD) 59 is provided.

Next, the configuration of the ink detecting section 8 which is a characteristic part of this embodiment will be described in detail.

FIG. 1 is a circuit diagram showing the configuration of the ink detecting section 8 of this embodiment.

In the figure, 101 is an LED which is a light emitting element, 102 is a phototransistor which is a light receiving element, 103 and 104 are resistors, 105 is a change amount of the collector current of the phototransistor 102, and the current is detected. Is a change amount amplification unit that amplifies and outputs a signal according to the change amount. Reference numeral 106 indicates a comparator.

In the above structure, the LED 101 emits light by the current determined by the power supply voltage V CC applied to the LED 101 and the resistance value of the resistor 103. When the phototransistor 102 receives light from the LED 101,
A reflector current IC is generated according to the amount of light. here,
When ink is ejected between the LED 101 and the phototransistor 102 and the amount of light reaching the phototransistor 102 decreases, the collector current IC decreases accordingly. As a result, the potential input to the variation amplification section 105, which is determined by the collector current IC and the resistance 104, changes.

The change amount amplifying section 105 amplifies only the charge amount of the input potential. The comparator 106 compares the reference potential Vref with the output potential of the variation amplification section 105, and outputs a low level signal 107 when the output potential of the variation amplification section 105 exceeds Vref. Thereby, the control unit 24
Measures the time width (pulse width) in which the signal 107 is at a low level, and determines that ink is present if the low level time is a predetermined time or more (ink ejection amount is a predetermined amount or more).

FIG. 6 shows a variation amplification section 10 of the present embodiment.
5 is a circuit diagram showing a configuration example of the ink detection unit 8 centering on a specific circuit configuration of No. 5, parts common to FIG. 1 described above are denoted by the same reference numerals, and description thereof will be omitted.

In the figure, 201 is a voltage follower circuit for impedance conversion, 202 is a capacitor, 2
Each of 03 and 204 is an input resistance and a feedback resistance of an amplifier circuit 210 including an operational amplifier 205, and the amplification degree of this amplifier circuit 210 is determined by Rf / Ri.

With this configuration, since the DC component is cut by the capacitor 202, the DC component of the output signal of the voltage follower circuit 201 is the operational amplifier 205.
Not entered in. Therefore, the potential of the signal generated by the collector current IC and the resistance value of the resistor 104 in the steady state is not amplified by the amplifier circuit 210.

In this state, the light emitting element (LED) 101 and the light receiving element (phototransistor) 1 are moved from the recording head 5.
When ink is ejected between the two, the amount of light detected by the phototransistor 102 decreases and the collector current IC changes (decreases). As a result, the collector current IC
The potential determined by the resistor 104 and the resistance 104 also decreases, and the amount of change in the potential, that is, the AC component is input to the amplifier circuit 210 through the capacitor 202 and amplified, and then the comparator 1
06 is compared with the reference potential Vref. When the reference potential Vref is exceeded, the comparator 106 outputs a low level signal. FIG. 7 shows the relationship between the potential at point a and the output signal of the comparator 106 at this time.

Here, since the amplifier circuit 210 amplifies only the amount of change in the potential, if the amplification degree is set large, it is possible to absorb the variation in the collector current IC due to the variation in the sensitivity of the phototransistor 102, and it is stable. Then, the ejection amount of ink can be determined. Further, since it is possible to detect a minute change amount of the collector current IC,
It is possible to reduce the amount of ink used for determining the ink ejection amount of the recording head 5. [Second Embodiment] FIG. 8 is a circuit diagram showing a circuit configuration of an ink detecting section 8 according to a second embodiment of the present invention. The parts common to those in FIG. .

In FIG. 8, 821 to 824 are resistors and 8
Reference numeral 25 indicates a capacitor, and 826 indicates a comparator.

Here, the potentials at points b and c in the steady state are expressed by the following equations, where I C is the current flowing through the phototransistor 102.

B = IC × (R1 + R2) c = IC × R2 At this time, since the potential at the point b is higher than the potential at the point c, the output signal 107 of the comparator 826 is at a high level.

Next, by ejecting ink from the recording head 5 between the light emitting element 101 and the phototransistor 102, the collector current IC of the phototransistor 102 decreases and becomes IC '(IC>IC'). To do. At this time, the potential b ′ at the point b is b ′ = IC ′ × (R1 + R2). However, the potential at point c is
Since it decreases with the time constant (C1 × R4) determined by the product of the capacitance (C1) of 5 and the resistance value (R4) of the resistor 824, if this time constant (C1 × R4) is set sufficiently large, the collector current will increase. When it decreases to IC ', the potential at point c becomes (IC
XR2) can be considered as it is.

Therefore, immediately after the collector current decreases,
b ′ <c, and the output signal 107 of the comparator 826
Is inverted to low level.

From the above equation, the comparator 826
In order to invert the output of, the following is required: IC '* (R1 + R2) <IC * R2 (R1 / R2) <{(IC / IC')-1}. Since the collector currents IC and IC 'are determined by the amount of light received by the phototransistor 102, the detection sensitivity can be adjusted by changing the ratio of the resistance values R1 and R2 of the resistors 821 and 822.

Then, as in the above-described first embodiment,
The control unit 24 measures the time (pulse width) during which the output signal 107 of the comparator 826 is at low level, and determines that ink is present if the output signal 107 is at low level for a predetermined time or longer.

FIG. 9 is a flow chart showing the ink amount detection processing of the ink cartridge in the ink jet recording apparatus of the first and second embodiments. The control program for executing this processing is stored in the ROM 26 of the control unit 24. And is executed under the control of the CPU 25.

First, in step S1, the carriage motor 3
0 is rotationally driven to move the carriage 15 toward the home position. When the home position is reached in step S2, the process proceeds to step S3, print data in which all dots are "1" is output to the print head 5, and ink is ejected by simultaneously driving all nozzles of the print head. In step S4, the signal 10
7 is input, and it is checked whether the signal level of the signal 107 is low level. If it is at a low level, the process proceeds to step S6 and, for example, the address of the RAM 27 is used as a counter and the content of the address is incremented by 1. And step S
This process is repeated until the signal 107 becomes high level at 7.

When the time when the signal 107 is at the low level is measured in this way, the process proceeds to step S8, based on the measured value (low-level pulse width). Determine the amount of ink in the ink cartridge. Then, the process proceeds to step S9, the result is displayed on the display unit 59, and the process ends.

On the other hand, if the signal 107 does not go to the low level in step S5, the process proceeds to step S10 to check whether or not a predetermined time has passed since the recording head 5 was driven. If not, the process returns to step S5. The signal level of the signal 107 is checked again. Then, if the signal 107 does not become the low level even after the lapse of the predetermined time, the process proceeds to step S11, it is determined that there is no ink, and the fact is displayed in step S9.

As described above, according to the present embodiment, in the ink amount detecting method for detecting the presence or absence of ink in the recording head by ejecting the ink between the photo interrupters, the ink is ejected between the photo interrupters. It is possible to easily detect the presence or absence of ink by amplifying only the change in the output of the photo interrupter caused by Can be possible.

Further, since a minute change in the output signal of the photo interrupter can be detected, it is possible to reduce the amount of ink used when determining the presence or absence of ink.

In the above embodiment, particularly in the ink jet recording system, a means (for example, an electrothermal converter or a laser beam) for generating heat energy as energy used for ejecting ink is provided, High density and high definition recording can be achieved by using a method of causing a change in ink state by energy.

With regard to its typical structure and principle, see, for example, US Pat. Nos. 4,723,129 and 4740.
What is done using the basic principles disclosed in 796 is preferred. This method can be applied to both the so-called on-demand type and continuous type, but especially in the case of the on-demand type, liquid (ink)
By applying at least one drive signal corresponding to the recorded information and providing a rapid temperature rise exceeding the film boiling to an electrothermal transducer arranged corresponding to the sheet or the liquid path in which 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. The liquid (ink) is ejected through the ejection openings by the growth and contraction of the bubbles to form at least one droplet. 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. 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 configuration of the recording head, in addition to the combination of a discharge port, a liquid path, and an electrothermal converter (a linear liquid flow path or a right-angled 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 converters,
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.

Further, it is preferable to add recovery means for the recording head, preliminary means, etc. to the structure of the recording apparatus described above because the recording operation can be made more stable. If these are specifically mentioned, capping means for the recording head, cleaning means, pressure or suction means,
There is an electrothermal converter, a heating element other than this, or a preheating means by 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 a single 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 is 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, 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 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, as a form of the recording apparatus according to the present invention, in addition to those provided integrally or separately as an image output terminal of an information processing apparatus such as a computer, a copying apparatus combined with a reader or the like, It may take the form of a facsimile machine having functions.

Further, the present invention may be applied to a system composed of a plurality of devices or an apparatus composed of one device. Further, it goes without saying that the present invention can be applied to the case where it is implemented by supplying a program to a system or an apparatus. In this case, the storage medium storing the program according to the present invention constitutes the present invention. Then, by reading the program from the storage medium to the system or device, the system or device operates in a predetermined manner.

[0076]

As described above, according to the present invention, a minute change in a signal due to an ejected ink droplet is detected,
There is an effect that the presence or absence of ink can be detected by amplifying the amount of change.

Further, according to the present invention, there is an effect that even a minute ink drop can be detected by using the photo interrupter.

[0078]

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of an ink detection unit according to a first embodiment of the present invention.

FIG. 2 is a side sectional view showing a configuration of an inkjet recording apparatus that performs recording by a recording head according to an inkjet system that is a typical embodiment of the present invention.

3 is a three-dimensional perspective view showing a detailed configuration of a recording unit A of the recording apparatus shown in FIG.

4 is a diagram showing a detailed configuration around an ink detection unit of a recording unit A. FIG.

FIG. 5 is a block diagram showing the configuration of the inkjet recording apparatus according to the present embodiment.

FIG. 6 is a circuit diagram mainly showing a configuration of a change amount amplification section of the ink detection section according to the first embodiment of the present invention.

FIG. 7 is a diagram illustrating an output signal of the circuit of FIG.

FIG. 8 is a diagram showing a specific circuit example according to the second embodiment of the present invention.

FIG. 9 is a flowchart showing an operation under control of the inkjet recording apparatus according to the present embodiment.

[Explanation of symbols]

 101 light emitting element (LED) 102 light receiving element (phototransistor) 103, 104, 821 to 824 resistance 105 change amount amplification section 106, 826 comparator

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Atsushi Saito 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Shigeyuki Sugiyama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Ken Kenno 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (11)

[Claims] 1. An inkjet recording apparatus for recording by moving a carriage carrying an inkjet head relative to a recording medium, the inkjet head being provided at a predetermined position within a moving region of the inkjet head. Detecting means for detecting the ejected ink and outputting a detection signal; amplifying means for amplifying a change in the detection signal; and ink ejection amount from the inkjet head based on the signal output from the amplifying means. An inkjet recording apparatus, comprising: a determining unit that determines 2. The detection means includes a light emitting element and a light receiving element, and a detection signal based on a change amount of light reaching the light receiving element due to ink ejected from the ink jet head between the light emitting element and the light receiving element. The inkjet recording apparatus according to claim 1, wherein 3. The ink jet recording apparatus according to claim 2, wherein the ink jet head ejects ink onto the optical axes of the light emitting element and the light receiving element. 4. The ink jet recording apparatus according to claim 1, wherein the amplification unit has a capacitor for inputting a signal from the detection unit and an amplification circuit for amplifying a current passing through the capacitor. 5. An inkjet recording apparatus for performing recording by moving a carriage having an inkjet head relative to a recording medium, the inkjet head being provided at a predetermined position within a moving area of the inkjet head. A light emitting element and a light receiving element that detect the ejected ink and output a detection signal, a first voltage value according to the output current of the light receiving element, and a predetermined value according to the change of the output current of the light receiving element. It has a comparison means for comparing with a second voltage value generated with a time constant, and a determination means for determining the ink ejection amount from the inkjet head based on the output signal of the comparator. Inkjet recording device. 6. The detection means includes a light emitting element and a light receiving element, and a detection signal based on a change amount of light reaching the light receiving element by ink ejected from the ink jet head between the light emitting element and the light receiving element. 6. The inkjet recording apparatus according to claim 5, wherein the inkjet recording apparatus outputs. 7. The ink jet recording apparatus according to claim 5, wherein the ink jet head ejects ink onto the optical axes of the light emitting element and the light receiving element. 8. The ink jet head includes an electrothermal converter, wherein heat applied to the ink by the electrothermal converter causes a state change in the ink, and the ink droplet is ejected by the state change. The inkjet recording apparatus according to claim 1, wherein the inkjet recording apparatus comprises: 9. An ink detection method in an inkjet recording apparatus for recording by moving a carriage carrying an inkjet head relative to a recording medium, the method comprising: moving the inkjet head to a predetermined position; A step of ejecting ink from the inkjet head at a position, and a photo interrupter having a light emitting element and a light receiving element provided at the predetermined position is used to amplify the variation of the output signal from the light receiving element An ink detection method characterized by detecting the presence or absence of ejection. 10. The ink detecting method according to claim 9, wherein the inkjet head ejects ink onto the optical axes of the light emitting element and the light receiving element. 11. The ink jet head includes an electrothermal converter, wherein the heat applied to the ink by the electrothermal converter causes a state change in the ink, and the ink droplet is ejected by the state change. The ink detection method according to claim 9 or 10.